NTT Technical Review

April 2020 Vol. 18 No. 4
Front-line Researchers

Shigeto Furukawa, Senior Distinguished Researcher, NTT Communication Science
Laboratories

Feature Articles: R&D on Security Contributing to Creation of New Value

R&D on Security Contributing to Creation of New ValueThe Future of Data Distribution and Its Security Technology



The Forefront of Cyberattack Countermeasures Focusing on Traces of Attacks



Cutting-edge Research on Cryptography Theory in Response to Changes in Computing
Environments

Feature Articles: Keynote Speeches/Workshop Lectures at Tsukuba Forum 2019
Working toward Sharing Social Infrastructure

Pioneering a Prosperous Future with Regional InnovationsTechnical Trends in Infrastructure Maintenance ManagementWireless Systems Technologies for Present and Future Services

Regular Articles
Compact Silica-based 16 × 16 Multicast Switch with Surface Mount Technology for PLCs

Global Standardization Activities


Activities of the APT/TTC BSG (Bridging the Standardization Gap) Working Group—Holdingof Ideathons in Cooperation with Universities in Southeast Asia

Practical Field Information about Telecommunication Technologies
Troubleshooting Case on Facsimile Communication by Analyzing IP and POTS Protocol

Information

Event Report: Tsukuba Forum 2019

External Awards/Papers Published in Technical Journals and Conference Proceedings

Front-line Researchers

Come as You Are and Identify Your
Standpoint
Shigeto Furukawa
Senior Distinguished Researcher, NTT
Communication Science Laboratories
Overview
In 2017, The Lancet, a medical journal, reported that hearing
loss is a risk factor for dementia; and thus, interest in hearing isincreasing worldwide. It is often thought that hearing loss isequated with the inability to hear low-level or high-frequency
sounds; however, the root of the problem is not limited to thatinability. We asked Shigeto Furukawa, a senior distinguishedresearcher at NTT Communication Science Laboratories, who
researches the auditory mechanism based on biological responses
that seem unrelated to hearing (such as the pupil) and analyzes
information about how sounds are heard subjectively, about his
latest research activities and the role of researchers.
Keywords: hearing, auditory mechanism, brain stem

Understanding hearing from biological responses—Tell us about your current research.
Although my research area has been written as“elucidation of the neural mechanism of sensory perception,” I am now mainly studying the auditory
mechanism (Fig. 1). Recently, I have been particularly interested in how we hear. For example, different people often hear the same sound differently, andeven the same person hears the same sound differently depending on the situation. Moreover, so-called“hidden hearing loss” is a problem concerning how tohear, and it is manifested as deteriorated hearing that
registers no abnormality in a hearing test.
It is often said that signals obtained from the eardrum and inner ear (lower-order processing) are recognized, understood, and interpreted in the brain(higher-order processing), especially in the cerebral
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Vol. 18 No. 4 Apr. 2020

cortex. However, various processes are also performed in the brainstem between the ear and cerebral
cortex (“intermediate processing”). It is the brainstem that retrieves basic information, such as pitch,and selects information that reflects the degree ofimportance. The brainstem also plays an importantrole in unconscious actions such as looking back in
response to a voice spoken from behind.
—The function of the brainstem is key to elucidating
the auditory mechanism.
We are therefore focusing on the intermediate processing carried out in the brainstem. The auditory andbrain mechanisms are often analyzed by inserting anelectrode into the brain of a test animal and measuring the electrical activities in the brain. However, wecannot insert an electrode into the human brain in thismanner, so we analyze the brain in an indirect way
1Front-line Researchers

Understanding
Cerebral cortex

Interpretation

High order

ActionAttention (heed)
EmotionInformation extraction
Brainstem

Information selection“Intermediate”

ReflexAttention (heed)
EmotionInner ear
Inne

Frequency analysis

Low order

Convert to neural signal

Fig. 1. Processing flow of auditory information.

—What applications can be considered in the future?
Let’s consider listening to music as an example.
Liking or not liking a song differs from person toperson, and even if the same person listens to a song,
his/her enjoyment of the song changes from time totime. By measuring the biological response of people
listening to a song, it may be possible to objectively
measure how each person feels at that time. Although
it seems that making that possibility a reality is a longway off, I am researching the idea that we can obtainhints by elucidating the relationship between attenNTT Technical Review

Vol. 18 No. 4 Apr. 2020

Frequency

Time
1000
800
Frequency (Hz)using non-invasive measurement techniques, such as
electroencephalograms (EEG) and eye movements,
and computer modeling.
For example, an EEG of a person hearing a soundoften includes the frequency components of a patternthat is similar to the sound presented (Fig. 2). Thesefrequency components are thought to originate fromthe brainstem, so analyzing them is a means to investigate brainstem activity. Moreover, it has been shownthat pupil size is linked to arousal level and attentionrelated neuronal-cell activity in the brainstem. On thebasis of these measurements and analyses, it is possible to access the functions of the brainstem without
having to pierce the brain with electrodes. Although
we are still far from elucidating the auditory mechanism of the brainstem, we hope that by combining
various measurement methods and modeling, we will
be able to reveal—from outside the body—the mechanism of hearing that occurs naturally at an unconscious level.

600
400
200
0

100

200
Time (s)300

400

EEG signal (bottom graph) contains the same frequency
components as that of the stimulus sound (top graph).

Fig. 2. B rainstem-derived EEG (frequency-following
response).

tion and hearing.
Let me introduce some of the research my team isworking on regarding attention. For example, I’m
considering whether the sound a person is paying
attention to can be determined by measuring thepupil. In fact, it has recently been reported that the2Front-line Researchers

Explore essential problems with an open mind
because the basic research field has a high degreeof freedom

0.8

Pupil diameter (z-score)

pupil changes with perceived brightness as well as
physical brightness. We have found that this phenomenon can also be applied to auditory attention (Fig. 3).
In an experiment, a participant listened to a soundthrough headphones while looking at a screen divided
in half; bright (left) and dark (right). Different sounds
were emitted from the left and right speakers of theheadphones. We found that when the participant was
told, “Pay attention to the sound from the left speakerwithout moving your eyes,” the size of the pupilchanged according to the brightness of the screen on
the side of attention (left), despite the fact that theparticipant did not move his/her eyes. In this example, when the left side of the screen was bright, thepupil diameter decreased. In other words, the participant’s attention directed toward the sound can bedetected visually from the outside as a change inpupil size. By using this phenomenon, it may be possible to determine to which speaker a person is paying
attention when multiple people are in conversation.
Regardless of the intent of the individual, someattention is directed according to external stimuli.
This attention is called “exogenous attention,” thestudy of which is more challenging. If someone is
asked, “What are you paying attention to?”, they will
become aware of their attention, and it will be impossible to measure their spontaneous attention correctly.
Owing to this fundamental difficulty, exogenous
attention to sound has not been extensively investigated. We believe that measuring pupil and eye movements can also be used to assess exogenous attention.
Although not well organized yet, these measurements
are providing new insights.

0.6

Attention to sound from thedark side (right)

0.4
0.2
Attention to sound from thebright side (left)

0
−0.2

0

1

2

3

4

5

6

Elapsed time (s)Fig. 3. C hange in pupil diameter when attention is paid toa sound to one ear while looking at the center of ascreen divided into light on the left and dark on theright.

first enrolled, I was interested in environmental
issues. However, over time, I gradually became
unable to identify the social issues I wanted toaddress. There was a reluctance to plant the seeds ofresearch by saying, “There is a problem” when there
was no such problem, so I became fascinated by purescience. One trigger of my interest in hearing camefrom entering a lab studying noise at university, eventhough the mainstream research undertaken in thedepartment was on sewerage, water treatment, and air
pollution.

—Why did you decide to become a researcher?
According to my parents, I wanted to be a doctor
when I was a child, and I seemed to have longed to
become a researcher since I was young. As I went
through high school and university, that longing
faded; however, as I watched others get office jobs atcompanies before graduating from university, I realized that I wanted to do something different. I thinkthat my consciousness of becoming a researcher was
greatly influenced by my supervising professor atthat time. The department in which I was enrolled(sanitary and environmental engineering) is strongly
focused on solving social problems; in fact, when I
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Vol. 18 No. 4 Apr. 2020

—What is the moment like when you are glad that you
have studied something?
Because the human brain is complex, examining
neural responses gives mixed results. Even if wemake a hypothesis, it is often not possible to clearlyshow from experimental results whether the hypothesis is correct. However, during the trial and error
used as an analysis method, even the mixed data ofcomplex neural responses of the brain may reveal
something useful depending on one’s ingenuity. I feelmost satisfied when I could make such revelations.
What you see at that time of a revelation is something
3

Front-line Researchers

seen for the first time in the world. Even if similar
research has been reported, you are the only one possessing the data that you measured on site, and you
are the one who chooses the analysis method.
—What do you do to devise research and analysis
methods?
It is often said that you should first set a goal, break
down the challenges posed by that goal, and finallyaddress what you need to do from then onwards. I’m
not saying that process is wrong, but I’m not too concerned about following those steps. As for basic
research, if you come across something interesting
during one of the steps, you have to have a sense offollowing it up by taking a detour. Something unexpected always happens at the research lab. I think that
applying one’s way of thinking at such times will leadto unique research.
When I reflect back, my activities sometimes
diverge too much or sometimes I am too particular
about what is in front of me and being too committed
to not knowing if it makes sense. Such a commitment
is an important quality for a researcher to have; evenso, I think it is necessary to pursue one’s research
while continuously questioning whether a small thingis just a small thing or whether it has importance.
The field of basic research has a high degree of
freedom. However, the fact that you are responsiblefor deciding what to research is actually a great dealof pressure. You can either apply your expertise toacademic research that focuses on details or you can
aim for major easy-to-understand results that meetthe expectations of top management. Although both
approaches must sometimes be taken by researchers,
I think that to ultimately contribute to the company,
society, or learning, I must pursue things that areimportant.
However, some things are important regarding
solving social problems, while others are essential
regarding understanding the principles of the universe. Although some problems are apparent becauseof one’s uniqueness and expertise, some of the problems faced by many people in society are vague but
essential and lying dormant. Therefore, I don’t think
too much about the problems I need to solve and wantto keep an open mind.

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You can identify your standpoint only when you
look back later—Please give a word to junior researchers.
As I continue my research, there are times when I
find it tough. When I was conducting physiologicalexperiments with animals, it was physically tough,and when I was doing detailed tasks like looking at
cells, I was worried that I would not be able to see theway ahead. When you reach an impasse like that, you
can do something else or seek a way around it. For
example, an idea may be revealed by discussing certain topics with the research community and colleagues. Even in simple discussions like chats, knowing what other people are interested in can confirm
your standpoint. If you know that you are such a person without deciding what you should be, you willknow the best way to live your life.
You may be able to identify your standpoint andway of life only by looking back later. Your work as a
researcher will vary. In addition to writing papers, therole of a researcher includes teaching people and running organizations such as research institutes andacademic societies. Even if you think that it is troublesome at the time, you may realize who you reallyare one day while fulfilling the roles as requested.
Although it may seem that there is nothing you cancontrol, because researchers ought to have a strong
personality, your standpoint won’t change so easily
even though you let it be.
In interviews with young people, I tell them thatpeople do not change much, so it is better to accept
them. No matter what you do, you will have a senseof self-worth. Advice to researchers such as, “That’s
wrong, so go in a different direction.” will not work.
I tell them to concentrate on whatever is going well,and you’ll eventually get some interesting resultsover time. I think a good approach is to consult withothers and help each other while being yourself; inthis way, each of us will be able to exert our abilities.
—What is the role of researchers in society?
In one sense, a researcher conducting basic researchis like a monk. Monks practice their religion, but thatpractice does not immediately help grow vegetables
and fill bellies. However, believers donate to monks
because they appreciate something in that practice.
Basic research (i.e., “practicing”) conducted byresearchers may not be immediately useful to theworld. However, if something overlooked or that was
4Front-line Researchers

vague is elucidated and made concrete by research,some people will come to consider making that
research useful. Also, when confronting the world’s
problems, we might find clues to solving them by taking a step back and looking at them abstractly. Boththe practice of monks and basic research are exactly
transitions between the abstract world and the realworld, and I think our responsibility lies in that transition. Some monks, such as novices, set themselvesapart from the world, while other monks live in society and connect with the world. I think that researchers can also take either path. I believe that it is betterfor each of us to contribute to society through our
research while thinking about our own path.
—Please tell us about your future prospects.
Up until now, the main target of auditory researchhas been the accuracy of correctly hearing information contained in sound and the mechanisms that support that process. I think that rather than the accuracyof hearing, the content and quality of perceived
sounds in daily life could become part of the research.
Assessing subjective hearing is not straightforward. I
believe that it is necessary to investigate and understand the perception, behavior, sensory nervous system, autonomic nervous system, and their closeinteractions. Fortunately, devices that measure biological responses, such as eye movements, pupils,
and brain activity, are rapidly evolving. As seen in theboom in artificial intelligence, machine-learningtechnology has made remarkable progress, and neuroscience has benefited from the analysis and modeling that it enables. I didn’t talk about this technology
in this interview, but I’d like to try applying such newtechnology to clarify the previously unknown mechanism of hearing. We have already obtained interesting
results concerning this mechanism. We also want todevelop technologies to evaluate and design sounds
that are easy for humans to hear. While I want toachieve results that have a social impact, I also want
to work on research that will be of interest to me only.
That may sound selfish, but if you don’t find yourself

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interesting, being a researcher will be boring.
Reference[1]

S. Furukawa, S. Yamagishi, H. Liao, M. Yoneya, S. Otsuka, and M.
Kashino, “Biological Measures that Reflect Auditory Perception,”
NTT Technical Review, Vol. 13, No. 11, 2015.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=
ntr201511fa3.html

Interviewee profile
Shigeto Furukawa
Senior Distinguished Researcher, HumanI n f o r m a t i o n S c i e n c e L a b o r a t o r y, N T T
Communication Science Laboratories.
He received a B.E. and M.E. in environmental
and sanitary engineering from Kyoto University
in 1991 and 1993, and a Ph.D. in auditory perception from University of Cambridge, UK, in 1996.
He conducted postdoctoral studies in the USA
between 1996 and 2001. As a postdoctoral associate at Kresge Hearing Research Institute at the
University of Michigan, USA, he conducted electrophysiological studies on sound localization,
specifically the representation of auditory spacein the auditory cortex. He joined NTT
Communication Science Laboratories in 2001.
Since then, he has been involved in studies on
auditory-space representation in the brainstem,
assessing basic hearing functions, and thesalience of auditory objects or events. As thegroup leader of the Sensory Resonance ResearchGroup, he is managing various projects exploringmechanisms that underlie explicit and implicit
communication between individuals. He is amember of the Acoustical Society of America, theAcoustic Society of Japan, the Association for
Research in Otolaryngology, the Japanese
Psychonomic Society, the Japan AudiologicalSociety, the Japan Neuroscience Society, and theJapanese Society for Artificial Intelligence.

5

Feature Articles: Security Technologies for Creating
New Value

R&D on Security Contributing toCreation of New Value
Shinichi Hirata
Abstract

NTT Secure Platform Laboratories is engaged in research and development of security technologies
required for a smart world. In this article, an information sharing platform of secure data utilization
required for a smart world is described, and the efforts of NTT Secure Platform Laboratories to support
that world are introduced from two aspects: security that protects the smart world and security that creates the smart world.
Keywords: data utilization, cryptography, security operation

1. The smart world

2. Recent trends in security

As typified by the key phrase digital transformation, digital data are being used by people in various
real-world settings, e.g., social activities, and the way
people live their lives and work is changing rapidly.
A large amount of digital data is acquired fromphysical spaces and used in various settings concerning social activities. Our aim to make use of digital
data is threefold: (i) process this large amount of datain cyberspace in sophisticated ways, return the data to
the physical space, and use them there; (ii) make itpossible for all people to live safely and in their own
way through those data-related activities; and (iii)enable society to work smoothly. We call this world
view a smart world. It is assumed that a smart world
will enable two types of optimization: personal optimization, namely, fulfilling safe and healthy living
through a personalized and customizable living environment, and social optimization such as creating
industrial systems that can achieve total optimization
based on forecasts and work environments that aresuitable for the requirements of workers (i.e., work
hours, places, etc.). We are striving to create security
technologies necessary for safe and secure use oflarge amounts of digital data, which is indispensable
for a smart world.

Society has started to make the major changes
needed to achieve a smart world; however, should we
not determine the nature of threats present in today’s
cyberspace before achieving this?
In information technology (IT), the following
threats are noteworthy: business-email compromise(BEC), namely, stealing management informationfrom a company using email, etc. and exploiting that
information to threaten or defraud people or businesses; supply-chain attacks targeting vulnerable parties (customers, contractors, etc.) in the product lifecycle (design, manufacture, use, and disposal) of
information devices; and activation of fake news
exploiting social networking services.
BEC involves attackers who infiltrate corporateinformation systems and spoof corporate transactions
and management information. In particular, an attack
attempts to steal money or confidential informationof a company by impersonating the compromised
company and exchanging fake information withrelated parties such as customers of the compromised
company.
According to a report by the FBI Internet Crime
Complaint Center released in April 2019, there were351,937 BECs in the USA in 2018 (up 17% from theprevious year), and the damage amounted to $2.7 billion (up 46% from the previous year) [1]. Moreover,

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Feature Articles

as an attack that attempts to steal confidential information from systems and networks and stop certain
functions, a supply-chain attack penetrates the product-design, manufacturing and distribution processes
then distributes hardware, firmware, software, etc.
that can attack third parties throughout the market. It
has become clear that such attackers have successfully distributed firmware and software, including
backdoors, to commercially available personal computers and smartphones.
In operational technology (OT) (i.e., control networks) and the Internet of Things (IoT), the numberof attacks on critical infrastructure has increased.
These attacks target control networks operating
inside public facilities that support people’s lives(such as electric, gas, water, communications, broadcasting, and transportation) by targeting these facilities. Actions that lead to suspension or destruction ofthese facilities are expected to disrupt the lives of the
public, for example, by stopping power transmission
from power plants and eventually causing large-scale
blackouts. The common trend in the above securitythreats is that cyberattacks have recently impaired the
security of the general public and nations. In otherwords, they are evolving into attacks targeting larger
victims.
3. Security technologies for protecting a smart
world and for creating a smart world
What security technologies must we provide for the
coming smart world? We are focusing on two keyphrases: protecting a smart world and creating asmart world. Security technology for protecting asmart world protects various networks and IT systems (such as IT, IoT, and Internet service providers)and users from cyberattacks. Security technology forcreating a smart world create a smart world by promoting secure data utilization by applying cryptography and supporting active use of data to activate corporate activities and ensure safe daily living. These
two key phrases are positioned as the two pillars
holding up our research and development (R&D) on
security.
4. Security technology for protecting asmart world
As described above in “Recent trends in security,”
it is expected that new cyberattack techniques willappear daily and the sophistication and expansion ofthese attacks will increase. The sophistication and
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Vol. 18 No. 4 Apr. 2020

increasing number of cyberattacks increase security
risks facing companies and organizations. The elements that make up security risks are broadly divided
into threats, vulnerabilities, and assets that companies
and organizations should protect. However, even for
major companies that value security, the cybersecurity budgets that individual companies and organizations can bear are limited to about 15% of their ITsystem budgets, and that figure drops to 5% or lessfor small and medium-sized companies. To counterthe spread of cyberattacks in the future, companies
and organizations must drastically improve their ability to defend against and counter cyberattacks(Fig. 1).
To improve the defense and countermeasuresagainst cyberattacks, we are developing the following
technologies in response to the sophistication of
cyberattacks: advanced technology for detecting malware in endpoint devices; advanced technology for
determining malicious domains; and technology tocounter attacks that exploit the psychological weaknesses of users. We are also developing the following
technologies in response to increasing number ofcyberattacks: technology for improving operational
efficiency and labor-saving technology for security
operations [2].
To counter cyberattacks in OT/IoT, under theassumption that various devices (such as IoT andcontrol) are connected, it is necessary to (i) ensure
security throughout the supply chain and the productlifecycle (spanning design, manufacturing, distribution, construction, operation, and disposal) and (ii)
implement multi-layer measures through cooperation
among industrial fields. Under the assumption that
IoT is going to be applied, for example, to factories,
buildings, agriculture, and monitoring and maintenance systems, we are advancing R&D on authenticity and integrity monitoring technology for IoT
devices, which detects software tampering of IoT
devices and control devices at the manufacturing,
distribution, and operation stages, and cyber physicalanomaly detection technology, which detects illegal
behaviors during operations. Moreover, in line withadvancements in the mobility field, such as sensor
networks for cars and autonomous vehicles, we arepushing ahead with R&D on real-time anomalydetection technology for in-vehicle networks andattack-detection technology on the cloud, whichquickly and accurately detect and analyze attacks
against vehicles and attacks by vehicles that havemalfunctioning in-vehicle networks, as well as fakesensor-data detection technology, which prevents7

Feature Articles=

Threats

Significant
Increase incybersecurity risks

×

Vulnerabilities

×

Assets

Improvements inability to defend
against and countercyberattacks areneededLimited cybersecurity budgets
Now

Cybersecurity budgets

Cybersecurity risks

Risk

FutureThreats• Increase in financial and political attacks• Increase in coordinated, commercialized, automatedattacks

Vulnerabilities• Increase in vulnerable devices the security
considerations of which are not sufficient

Assets• Various and large number of devices (e.g., sensors,
cameras, factory, vehicles, and consumer electronics)
are connected to the Internet• Increase in sensitive information stored into devices
and cloud services

Cybersecurity budgets• Even for major companies that value security, budgets are limited
to about 15% of their IT system budgets. This is 5% or less forsmall and mid-sized companies• It is difficult to increase cybersecurity budgets

Fig. 1. Cybersecurity risks and budgets.

confusion regarding traffic information due to mixingof false sensor data. In addition to the above-mentioned technologies as countermeasures against
cyberattacks on OT and IoT systems, we must develop integrated countermeasures and formulate rules
based on the interdependence of IT security, functional safety, and physical security.
5. Security technology for creating asmart world
To create a smart world, it is essential to provide
technologies that support safe data distribution anduse, namely, solving problems caused by unauthorized use of data, data hoarding, and privacy breaches.
These technologies are composed of a flexible andsecure data distribution and analysis mechanism thatcan use data across fields and enable secure executionof all value-creation processes (from data generation,utilization, and analysis to disposal).
Data have thus far been held and used only within asingle business entity. However, to create a smart
world, the following mechanisms are required: forconducting advanced analysis (integrated analysis)by combining secured data to keep privacy and trade
secrets while sharing them between organizations;and for solving various issues and returning the solutions to society on the basis of the results of crosssector integrated analysis. These mechanisms will
enable secure data utilization across industries andfields while creating unprecedented new value(Fig. 2).
We are working on secure computation technology
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Vol. 18 No. 4 Apr. 2020

to compute a function on encrypted data and anonymization technology that enables safe use of personal
data as core technologies to enable such value creation [3]. When analyzing and utilizing data, the data
generally have to be decrypted; thus, data utilization
related to sensitive data (e.g., trade secrets and personal information) is not progressing. The abovementioned secure computation technology supports
the creation of a world that facilitates solving problems by taking into account the handling of information related to individuals and companies then sharing necessary data between organizations according
to the purpose. In September 2019, we announced theworld’s-first secure computation technology enables
model training with a deep neural network while
training data are kept secret [4].
Anonymization technology makes it possible tocreate various anonymously processed information,
including data concerning the proprietary technologyof NTT Secure Platform Laboratories. With theenforcement of the revised Act on the Protection of
Personal Information of 2017 in Japan, if personal
information is processed as anonymously processed
information, it can be provided to third parties without the consent of the individual. The anonymization
technology of NTT Secure Platform Laboratories,
which is in compliance with the above act, has beencommercialized as anonymously processed information creation software by NTT TechnoCross Corporation.

8

Feature Articles

Data utilization in smart world:
Creates new value while enabling
secure and safe data utilization throughcross-organizations

New value

New value creation
enabling safe and securedata utilization

Organization (corporation, supply chain, etc.)
Data analysis
platform
Current data utilization:
Limited data utilization (e.g., single company,
single supply chain, etc.)

Network

AnalysisCloud

Organization Organization …
Data
Data
analysisanalysis …
platform
platform

Edge

Endpoint

Network

Network…

Endpoint

Endpoint…

Provision of data

Utilization of data

Fig. 2. Data utilization in a smart world.

6. Activities related to Center of
Excellence (CoE)We are actively involved in activities at NTT’s CoEwith the aim of creating technology that enable thecompetitiveness necessary for the NTT Group to support a smart world.
Through the activities of the CoE, our highly
skilled human resources are taking the initiative in theacademic and professional communities. Regarding
cybersecurity, we are focusing on management ofexpert communities and global security contests aswell as development of human resources in collaboration with universities. Regarding data security, withan eye on 10 to 20 years from now, we are also
researching fully homomorphic encryption, which
can be called the next generation of secure computation; post-quantum cryptography, which maintains
security even if quantum computing becomes a reality; and quantum computing as the world’s-mostadvanced research for cryptography [5]. We are also
focusing on consulting activities to use the knowledge thus far accumulated at NTT Group companies
and supporting the development of safe and securesystems and applications that comply with privacy
protection and legal systems.

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7. Future developments
As described in this article, NTT Secure Platform
Laboratories is engaged in various R&D activities
related to security with the aim of becoming thesource of the advancement and differentiation of the
NTT Group’s security technologies while striving tocreate a safe and secure smart world.
References
[1]

[2]

[3]

[4]
[5]

Press release issued by FBI, “FBI Releases the Internet Crime Complaint Center 2018 Internet Crime Report,” Apr. 22, 2019.
https://www.fbi.gov/news/pressrel/press-releases/fbi-releases-theinternet-crime-complaint-center-2018-internet-crime-report
M. Iwamura, Y. Kanemoto, Y. Kurogome, K. Aoki, Y. Kawakoya, S.
Orihara, and J. Miyoshi, “The Forefront of Cyberattack Countermeasures Focusing on Traces of Attacks,” NTT Technical Review, Vol. 18,
No. 4, pp. 16–21, 2020.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=
ntr202004fa3.html
T. Miyazawa, T. Fukunaga, G. Takahashi, R. Kikuchi, S. Takahashi,and S. Hasegawa, “The Future of Data Distribution and Its Security
Technology,” NTT Technical Review, Vol. 18, No. 4, pp. 11–15, 2020.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=
ntr202004fa2.html
Press release issued by NTT, “Secure Computation for a Typical
Training Algorithm of a Deep Neural Network,” Sept. 2, 2019.
https://www.ntt.co.jp/news2019/1909e/190902a.html
M. Abe, Y. Tokunaga, M. Tibouchi, R. Nishimaki, and K. Xagawa,“Cutting-edge Research on Cryptography Theory in Respond to
Changes in Computing Environments,” NTT Technical Review, Vol.
18, No. 4, pp. 22–26, 2020.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=
ntr202004fa4.html

9Feature Articles

Shinichi Hirata

Vice President, Head of NTT Secure Platform
Laboratories.
He received a B.S. from Hokkaido University
in 1990. He joined NTT in 1990 and has been
engaged in R&D of cryptography, IC card technology, and authentication systems.

NTT Technical Review

Vol. 18 No. 4 Apr. 202010

Feature Articles: Security Technologies for Creating
New Value

The Future of Data Distribution and
Its Security Technology
Toshiyuki Miyazawa, Toshinori Fukunaga,
Gen Takahashi, Ryo Kikuchi, Seiji Takahashi,and Satoshi Hasegawa
Abstract

With the acceleration of digital transformation, the value of data is ever increasing, while concerns
about security risks and privacy are growing stronger. At NTT Secure Platform Laboratories, we intend
to address these issues with cryptographic technology and create a world in which data owned by individuals and organizations are provided and used at the minimum level necessary according to the purpose to enable problem solving. In this article, specific initiatives undertaken at NTT laboratories tosupport secure data distribution in such a world are introduced.
Keywords: multi-party key sharing, secure-computation AI, anonymous processing

1. The Future of data distribution
With the acceleration of digital transformation(DX) in various fields, it is expected that the digitization of people, goods, processes, etc. of companies
and organizations will progress and that advanced
analytical processing will make it possible to address
issues such as value creation and improving operational efficiency. While the value of data has increased
in line with these trends, security risks and privacy
concerns have also intensified.
With the globalization of corporate activities andthe spread of the cloud and Internet of Things, various
and diverse entities (people, terminals, organizations,etc.) have become interconnected. As various types ofdata are exchanged and shared by these entities, therisk of theft or leakage of the data affecting companies and individuals has also increased. Concerns
about legal restrictions and privacy regarding using
personal and corporate information for artificial intelligence (AI) and machine learning—which play
important roles in DX—are also growing.
To eliminate such risks and concerns, NTT Secure
Platform Laboratories wants to use cryptography tocreate a world in which data concerning products or
NTT Technical Review

Vol. 18 No. 4 Apr. 2020individuals can be safely exchanged according to the
purpose and enable problem solving (Fig. 1). The following technologies that support such secure data
distribution are introduced in this article: (i) dataencryption and related technologies for protecting allcommunications end-to-end; (ii) secure-computation
AI for enabling advanced integrated analysis while
protecting corporate secrets and privacy; and (iii)
anonymization technology for processing personal
data in a manner that does not identify individuals
and encourages the use of that information.
2. Data encryption and related technologies
Important data used in data distribution can only beexchanged and shared between multiple entities(individuals, organizations, terminals, etc.), and it isimportant that information not be leaked to other entities. In consideration of the risk of information leakage from service providers recently, it has become
increasingly necessary to keep data confidential evenfrom the companies that provide data-distribution
services and their system administrators.
To satisfy this requirement, it is desirable that (i) asecret key to the encryption is shared between trusted
11

Feature Articles

Value creation by secure data utilization
beyond industries and fields

Advanced integrated analysis while
protecting corporate secrets and privacy

Secureanalytics
platform
Network
services

Schedule,
location info.,
messages

Suggestion of
meeting place
and time

Location
info., traffic
condition,
event
schedule

Optimal route

Stock,
demands

Production
schedule

Securead-hocnetwork
Optimized delivery
plan and method

People, devices, and organizations sharing
data safely for problem solving

Fig. 1. Secure data distribution.

entities and the data to be exchanged and shared are
encrypted with the secret key and (ii) the shared data
can be searched. However, enabling these processes
faces two major technical challenges. The first challenge is efficient key sharing among multiple entities.
It is required to share keys among many entities; however, it is inefficient and impractical to repeatedly
execute a key-sharing protocol between two parties
using multiple systems.
In light of the above-described circumstance, NTT
is studying technology that enables efficient sharingof keys among multiple entities via a key-mediation
server installed by a service provider. The key-mediation server guarantees in principle that the shared
key cannot be reconstructed. We developed a method
for enabling efficient key sharing for a fixed period
regardless of the number of entities. This method
enables exchange and sharing of data concealed frominformation-distribution service providers by using
only an arbitrary number of entities involved in communication at that time.
The second challenge is to search for encryptedshared data by using the computer resources of thedata-distribution service provider. Since data-distribution services are often provided in cloud form, it isdesirable to search for shared data by using the computer resources of the data-distribution service provider; however, if the encrypted data are decrypted
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

for such a search, the data cannot be concealed fromthe service provider. With this issue in mind, NTT is
studying a method of enabling this concealed search
by encrypting the search index separately from thedata and searching with the encrypted search index.
As mentioned above, the processing is complicatedbecause shared data are frequently re-encrypted every
time an entity is added or deleted. We are thus devising a method of doing this efficiently.
For technology related to the two above-mentioned
challenges, we have also developed technology for
efficiently re-encrypting data with a new key without
encrypting the shared key (encrypted when the shared
key was updated) each time an entity is added ordeleted. Combining the above-mentioned method
and technology, we have already commercialized
communication services such as telephony and online
chat that do not leak data to service providers [1].
3. Secure-computation AI
It is generally necessary to restore (decrypt) theoriginal data during processing for data utilization,even if they were encrypted during communication orstorage. Data owners know that this processing mayleak information, so many users and organizations
are reluctant to use data related to trade secrets andpersonal privacy. This is considered a major obstacle,
12Feature Articles

Process on encrypted data

Training

Model
Prediction
resultFig. 2. Secure-computation AI.

especially when data are to be provided, actively
used, and transferred from their owner to anotherparty or even distributed within the same organization.
To help eliminate such obstacles, NTT is leading
the world in research and development (R&D) ofsecure-computation technology that can process data
while encrypting them. With this technology, dataencrypted using the confidential-data-sharing technology standardized by the ISO (International Organization for Standardization) can be analyzed without
first restoring them to the original form. This is
expected to contribute to the creation of a world inwhich information (such as confidential informationof companies and information concerning personalprivacy) can be safely and securely provided andused. This technology has reached the practical stage.
NTT is currently researching and developing
secure-computation technology that enables moreadvanced analysis. We have recently developed aworld-first technology that can process a standard
algorithm used for deep learning, which has begun to
be used in the AI field, without restoring encrypted
data to the original data [2]. In other words, all thesteps necessary for data utilization in deep learning,
namely, data provision, data storage, learning processing, and prediction processing, can be carried out
on data in the encrypted state (Fig. 2). We believe that
this technology will allow data owners to provide
data with peace of mind when using the data with AI,
leading to an increase in the amount and types of data
while enabling advanced analysis with improved
accuracy. For example, the technology is expected tomake the following possible: (i) by learning personallocation information and schedules in conjunction
with weather and corporate-event information, etc., it
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

will be possible to anticipate the most appropriate
purchases and staffing resources for restaurants; and(ii) by learning medical data (such as X-rays, magnetic resonance imaging, computed tomographyscans, and micrographs) while keeping them concealed, it will be possible to quickly and accurately
determine whether malignant tumors are present intest results.
In the future, we plan to demonstrate the effectiveness of deep learning using secure computation by
conducting proof experiments in cooperation withpartners who have AI expertise.
4. Anonymization technology
The use of personal data has recently become thefocus of attention, and the market for such use isabout to be activated in earnest. Under such circumstances, NTT is researching data-processing technology that promotes safe use of personal data.
According to the revised Act on the Protection of
Personal Information of 2017, “anonymously processed information” (namely, personal information
processed in a manner that a specific individual cannot be identified and the personal information cannot
be restored) can be provided to third-parties and used
for tasks other than the specified purpose without theconsent of the person in question. For example, byallowing manufacturers to use anonymously processed information made from purchase-history data
possessed by retailers, the manufacturers could
develop new products in accordance with consumer
attributes and purchasing habits.
If only anonymity is to be enhanced, the characteristics of the original data will be greatly impaired, andthe data will be less useful. Accordingly, to satisfy
13Feature Articles

Non-anonymized database table
Sex

Age Occupation

Sato

Shinjuku, Tokyo

Male

45

employee

Suzuki

Mitaka, Tokyo

Male

41

employee

Abe

Shinjuku, Tokyo

Female37

housewife

Nagasawa Shinagawa, Tokyo Female

35

housewife

Yamamoto Funabashi, Chiba

Male

32

employee

Kobayashi

Chiba, Chiba

Male

57

UchidaKashiwa, Chiba

Male

59

selfemployed
selfemployed

Conventional method

Address

NTT’s original methodNamekanonymization
Generalize& Suppress
Information

Name

Address

Sex

Age

Occupation

**

Tokyo

Male

40s

employee

**

Tokyo

Male

40s

employee

**

Tokyo

Female30s

housewife

**

Tokyo

Female30s

housewife

**

Chiba

Male

30s

employee

**

Chiba

Male

50s

self-employed

**

Chiba

Male

50s

self-employed

Cannot be distinguished from at least 1 individual  k = 2****

Pk-anonymization• A method for satisfying anonymity by stochasticallychanging pieces of data.
• NTT proves an anonymity equivalent to k-anonymity
by randomization for the first time.  Pk-anonymization• This method can be used with anonymity without
generalization or suppression.

Shinjuku, Tokyo

Male

53

employee

Mitaka, Tokyo

Male

41

self-employed**

Shinagawa, Tokyo Female

37

housewife**

Shinagawa, Tokyo

Male

35

housewife**

Shinjuku, Tokyo

Female32

housewife**

Chiba, Chiba

Male

45

self-employed**Kashiwa, Chiba

Female59

self-employed

Fig. 3. Pk-anonymization.

both the data owner’s need to reduce the risk of leaking
personal identification and the data user’s need toobtain data that retain the characteristics of the original data, optimal anonymous processing is needed.
NTT has thus developed anonymously processed
information-creation software for creating anonymously processed information that balances anonymity and usefulness. This software has been available
in Japan from NTT TechnoCross since 2018, and its
market development is progressing mainly in the
medical and financial fields.
This software features various anonymization andevaluation techniques to comply with Processing
Standards Nos. 1 to 5 for anonymously processed
information specified by the Personal Information
Protection Committee. One of these techniques is
NTT’s original anonymization technique called “Pkanonymization,” which ensures high usability without changing the data granularity by using a perturbative method. As the conventional technology, K-anonymization secures k-anonymity* by abstracting databy for example, changing “33 years old” to “30s” and“Chiyoda ward, Tokyo” to “Tokyo”; however, it isaffected by information loss. In contrast, when Pkanonymization (which disturbs data) is introduced,
no information is lost, and more accurate and broader
analysis is possible (Fig. 3).
With the aim of creating a world in which data are
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

more actively used, NTT is working on reducing therisk of leaking personal identification as well as ofinferring personal attributes. For data utilization, it isproblematic that when calculation results such as
statistical information are used, for example, if theaverage test scores of two people are used, a person
who knows the score of one of them can estimate thescore of the other. Privacy concerning such calculation results is called “output privacy,” which has been
widely studied in statistics. NTT is focusing on output privacy of machine learning, which is a promisingdata-analysis technology, and continuing to researchrisk-analysis and protection technologies related tomachine learning.
5. Future directions
To enable secure data distribution, as introduced at
the beginning of this article, NTT is designing anddeveloping various encryption technologies in addition to those introduced in this article. Examples ofthese efforts are (i) development of cryptosystems
and evaluation of their security in anticipation of thecreation of quantum computers (the R&D of which is*

K-anonymity: The characteristic that the corresponding individual cannot be identified from the processed data with a probabilityof 1/k or more.

14

Feature Articles

accelerating) and (ii) cryptographic program obfuscation, which makes the processing content of a program cryptographically non-analyzable and enables
distribution of secure programs [3]. On the basis of
our expertise in cryptographic theory and technology,
we will conduct R&D on data security that contributes to the resolution of problems of NTT Group’s
customers and social issues.

References
[1]

[2]
[3]

Toshiyuki Miyazawa

Manager, Research and Development Planning
Department, NTT.
He received a B.E. and M.S. in mathematics
from Waseda University, Tokyo, in 2000 and
2003. Since joining NTT in 2003, he has been
engaged in R&D of cryptography and security
management.

R. Yoshida, Y. Okano, H. Okuyama, and T. Kobayashi, “A Secure
Business Chat System that Prevents Leakage and Eavesdropping fromthe Server by Advanced Encryption Technology,” NTT Technical
Review, Vol. 15, No. 5, 2017.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=
ntr201705fa4.html
Press release issued by NTT, “Secure Computation for a Typical
Training Algorithm of a Deep Neural Network,” Sept. 2, 2019.
https://www.ntt.co.jp/news2019/1909e/190902a.html
K. Xagawa, “Research Trends in Quantum-resistant Cryptography,”
NTT Technical Review, Vol. 17, No. 3, pp. 22–26, 2019.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=
ntr201903fa4.html

Ryo Kikuchi

Research Engineer, NTT Secure Platform
Laboratories.
He received a Dr. Eng. from Tokyo Institute ofTechnology in 2015. Since joining NTT in 2010,
he has been engaged in R&D for secure data
sharing through secure multiparty computation,
anonymization, and statistical disclosure control.
He was a visiting researcher at the National Statics Center from 2016 to 2018 and has been an
expert in ISO/IEC JTC 1/SC 27/WG 2 since2013. He received ACISP (Australasian Conference on Information Security and Privacy) 2019/
Computer Security Symposium (CSS) 2012/
CSS2013/CSS2017 best paper awards and SCIS
2017 innovation paper award.

Toshinori Fukunaga

Senior Manager, Human Capital Management
Group, Research and Development Planning
Department, NTT Secure Platform Laboratories.
He received a B.E. and M.E. in electrical engineering from Chiba University in 1996 and 1998
and joined NTT in 1998. He has been engaged in
cryptographic engineering and information security management system.

Seiji Takahashi

Senior Research Engineer, NTT Secure Platform Laboratories.
He received a master’s degree in science andengineering from Ehime University in 1999.
Since he joined NTT in 2000, he has been
engaged in system development applying information security technology.

Gen Takahashi

Senior Research Engineer, Secure Data Sharing Project, NTT Secure Platform Laboratories.
He received a Master of media and governancefrom Keio University, Tokyo, in 2005 and joined
NTT in 2006. His research interests include
information security and cryptographic engineering. He received the Symposium on Cryptography and Information Security (SCIS) Paper
Award from the Institute of Electronics, Information and Communication Engineers (IEICE) in
2008.

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

Satoshi Hasegawa

Researcher, Data Security Project, NTT Secure
Platform Laboratories.
He received a Master of computer science from
University of Tsukuba, Ibaraki, in 2014.
Since joining NTT Secure Platform Laboratories in 2014, he has been engaged in R&D of
enhanced privacy-preserving technologies, especially of anonymization and secure multi-party
computation. He received the CSS Encouragement Award and DICOMO (Multimedia, Distributed, Cooperative, and Mobile) Symposium Best
Paper Award from the Information Processing
Society of Japan in 2016 and 2017.

15

Feature Articles: Security Technologies for Creating
New Value

The Forefront of Cyberattack
Countermeasures Focusing on Tracesof Attacks
Makoto Iwamura, Yo Kanemoto, Yuma Kurogome,
Kazufumi Aoki, Yuhei Kawakoya, Shingo Orihara,
and Jun Miyoshi
Abstract

Cyberattacks have become more capable of infiltrating corporate networks with malware by skillfully
deceiving the target, and it is becoming increasingly difficult to prevent infections before they occur.
Regarding web servers that are open to the public, the frequency of attacks increases and alerts occur
more frequently as attack techniques become well known. It is thus becoming difficult to determine
which attack to respond to. In this article, the forefront of cyberattack countermeasures focusing on
traces left by attacks is discussed to address this issue.
Keywords: cyberattack countermeasures, malware analysis, alert triage

1. Current status of endpoint defense
Targeted attacks aimed at companies and the malware (malicious software) used in those attacks are
becoming more sophisticated daily, and it is becoming difficult to prevent intrusions before they occur.
Under such circumstances, a technique called endpoint detection and response (EDR) is attracting
attention. EDR takes measures to be taken after an
intrusion into account under the assumption that an
intrusion by malware will be allowed.
Conventional security products prevent infection
by detecting the apparent characteristics of malware(such as patterns included in executable files of themalware) as rules before the malware is executed.
However, malware that changes its apparent characteristics and escapes detection by security products
has started to be used in recent targeted attacks. The
apparent characteristics of malware can be changed
relatively easily. On the contrary, post-infection
behavior is closely related to what the malware isintended to do, and it is considered difficult to change
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

that behavior compared to changing the apparent
characteristics. EDR is used to combat such targeted
attacks by detecting the behavior of malware after it
has begun to spread and leave traces behind.
A rule that detects traces that remain when a computer is infected with malware is called an indicatorof compromise (IOC). Depending on the EDR product used, malware infection can be detected with auser-created (“custom”) IOC. Traces left by malware
infection and how to generate an IOC to detect them
are described in the following sections.
2. Traces of malware infection andtheir detection
Let us suppose that a file named “mal_a.txt”
remains as a trace when malware infects a terminal.
To detect that trace, it seems appropriate to prepare an
IOC whose file name is “mal_a.txt.” However, when
the same malware infects another terminal, if the filename becomes “mal_b.txt,” it cannot be detected by
the original IOC. In this case, a little ingenuity is
16

Feature Articles

3. Candidate generation

1. Malware collection
and selection
AccuracyHigh

Behavior log
File Name:
mal_a.txt
mal_b.txt
mal_c.bin
Registry Value:
HKEY_LOCAL_MACHINE¥…
= ‘%System%¥zzzz.exe, …’
URL:
http://xxx.net/yyy.php?n=…
Command-line:…

Abstract level 1
mal_a¥.txt
mal_b¥.txt
mal_c¥.bin

Coverage
Low

te
ima
itim
Leg ftware gs
so iioor lo
avbeh

2. Malware analysis

4. Optimizationt
trac
Abs l 1leveorAbstract level 2

or
Abstract level 3
mal_.*¥.. *Ab
lev stra
el ct
2

e
ar .
w fo
al in
M ily
m
fa

Abst
ra
level ct3

mal_[a|b]¥.txt
mal_c¥.bin

Low

are
Malw r logs
avio
h
e
b

argmaxHighnIOCs Items×Labels i =1

weighti * funci (IOCs)
Abstract level 2

IOC

Fig. 1. Automatic generation of IOC.

applied and an IOC is created whose file name is“* .txt” (where * is an arbitrary character string). That
IOC will cover both “mal_a.txt” and “mal_b.txt” andmight cover other traces that may appear in the future.
However, normal applications that are not malware
are also running on terminals monitored using EDR.
If a normal application creates a file called “leg.txt,”
the IOC “* .txt” will detect that file as a trace of malware. Although it is harder to change post-infection
behavior than the apparent features of malware thatprior technology focuses on, an IOC must be
expressed in a manner that does not cause false detection while increasing coverage so that it can follow
the changes in traces.
One more point must be taken into account when
considering what is required of an IOC. Let us suppose an IOC detects that the malware has actuallyinfected a terminal. Much of the subsequent work isleft to security engineers, i.e., people. It will be possible to determine, for example, the path the malware
entered by, whether it has sent confidential information to the outside, whether any other terminals are
infected, and clarify those findings from remaining
logs. It may be necessary at times to know what the
IOC has detected, improve the IOC, and test otherdevices. All this is required for an IOC to make it easy
for people to see and interpret. Detection criteria arevery complex for certain types of machine learning,and some algorithms are difficult to understand, letalone improve. In the field of security, in which people exist in a series of work flows, the interpretability
NTT Technical Review

Vol. 18 No. 4 Apr. 2020of an IOC also becomes important.
3. Automatic generation of IOC
NTT Secure Platform Laboratories is researchingand developing malware-analysis technology thatcomprehensively identifies the behavior of malware
that has various anti-analysis functions. The automatic IOC generation technology [1] introduced here
generates an IOC with high detection accuracy, coverage, and interpretability by using the behavior logs
extracted with that malware-analysis technology as
input. Specifically, an IOC is generated by the following procedure (Fig. 1).
(1)	Malware collection and selection: Collect andselect malware according to the environment
to be monitored by the IOC.
(2)	Extraction of a behavior log with malwareanalysis technology: Analyze malware in a
virtual environment dedicated to malware
analysis and extract a behavior log of the malware. Our malware-analysis technology isused for this task.
(3)	Generation of IOC candidates with multiple
abstractions from malware-behavior logs:
Generate regular expressions with various
abstractions that can be candidates of an IOC
from past malware-analysis knowledge.
(4)	Calculation of optimal IOC set based on detection accuracy and ease of interpretation: Foreach of the above-generated IOC candidates,
17

Feature Articles

Administrative network
B
A

Conventional

E
H

D

IOC

G
J

C

IOC

Detect infected
hosts

F

IOC

IOC

Our
technology

user A …
user B …
user C…
user D…
user E …

user F …
user G…
user H…
user I …
user J …

user A …
user B …
user C…
user D…
user E …

user F …
user G…
user H…
user I …
user J …

I

Custom IOCs
EDR manager

Endpoint hosts

Fig. 2. Use of custom IOCs.

consider detection accuracy and ease of interpretation on the basis on the behavior logs oflegitimate software and malware and calculate
the optimal IOC for each malware family.
By adding the generated IOC to EDR products on
the market, it will be possible to detect malwareinfected terminals that have been conventionally difficult to detect (Fig. 2). Currently, we collect andselect about 10,000 samples per week, and we havestarted distributing the IOCs generated from theresults of analysis of that collection of malware to the
NTT Group. In the future, we will continue torespond to malware other than those with executable
file formats (such as script format).
4. Current state of public-server defense
Whenever a new vulnerability is discovered on aserver or application, cyberattacks target that vulnerability. Cyberattacks that exploit vulnerabilities ofservers and applications have exceeded 10 million
per day worldwide. To detect and block these attacks,
it is becoming common to deploy security devices
such as an intrusion prevention system (IPS)*1 or
web-application firewall (WAF) *2. Ideally, thesesecurity devices should correctly detect and block all
attacks. Realistically, however, it is difficult to do
this. The reason is that quality of service will degrade
due to false blocking. If the security device is nottuned sufficiently by the operator, normal communication may be detected and blocked. Due to this risk,
it is difficult to block all attacks without tuning by theoperator. Therefore, only detection, such as intrusion
detection system (IDS)*1, is conducted in most cases.

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

5. The need for more-efficient
security operations
A computer-security-incident response team
(CSIRT) or security operation center (SOC) analyst
responds to cyberattacks occurring in a company ororganization. CSIRTs and SOC analysts analyze data
daily for security breaches on the basis of alerts sentfrom security devices.
In particular, WAFs and IDSs that detect server
attacks report thousands or tens of thousands of alerts
every day, and violations are analyzed on the basis of
the knowledge and experience of the analysts. As aresult, if the alerts are not prioritized to the moreimportant ones, it will not be possible to handle allalerts generated in a limited time span.
This prioritization is something that can only bedone by a few analysts with knowledge and experience, and now that attacks are growing in scale, it is
not practical to analyze all attacks entirely manually
because not everyone can do that analysis. Moreover,
the attacker can adopt a tactic that requires only asingle instantaneous attack of choice to achieve thepurpose of the attack while launching many meaningless attacks. Such a tactic paralyzes corporate security monitoring, preventing CSIRT and SOC analysts
from noticing the real attack in a timely manner.
6. Alert-triage technology
At NTT Secure Platform Laboratories, we have
*1 IPS/IDS: A system that protects applications from attacks that
exploit vulnerabilities; IDS refers to a usage mode that performs
only detection, while IPS refers to a usage mode that blocks detected attacks.
*2 WAF: A system that protects applications from attacks in a similar manner to IPS/IDS. It has a detection capability specialized
for web applications.

18

Feature Articles

Current
WAF

ClientInvestigate large

Servernumber of alerts: AlertAlert-triage technology

Investigate only cri

tical alerts

Alert-triage
technology: High priority
alert

Fig. 3. Alert-triage technology.

(1) Extraction of
attack code

Network packets(2) Emulation

Attack code

(3) Judgement

IOC

Result• Success• Failure• Unknown

Fig. 4. Basic functions of alert-triage technology.

developed an alert-triage technology [2, 3] that automatically determines the success or failure of an
attack on a server (from a network communication)from the trace of the attack and determines whether
the alert associated with that attack should be given
priority. This is the world’s first technology for performing triage (prioritization) by focusing on the
success or failure of an attack. This technology
NTT Technical Review

Vol. 18 No. 4 Apr. 2020enables a server administrator or SOC analyst to concentrate on attacks that require immediate response(Fig. 3). The basic functions of this technology arelisted as follows (Fig. 4).
(1)	Extracting the code or command that theattacker wants to execute on the server if theattack is successful(2)	Executing the extracted attack code or command
19

Feature Articles

Time

Alert

Sourcey.y.y.yFailureResponse
priority*
Low

y.y.y.ySuccessHigh

y.y.y.yUndeterminable Medium

Destination Attack result*Dec. 2, 2019 Remote code execution
x.x.x.x
21:38:12
attack detected
Dec. 2, 2019 SQL injection attack
x.x.x.x
21:43:03
detected
Dec. 2, 2019 Cross-site scripting attack x.x.x.x
21:43:15
detected* Information added by our technologies

Fig. 5. Examples of the alert triage.

on an emulator simulating various servers andextracting the trace of the attack (i.e., IOC)(3)	Checking whether the IOC extracted from theemulator was occurring in the actual communication and judging that the attack was successful if it occurred or failed if it did notoccur.
When an alert occurs, it is possible with this technology to add information to the alert that (i) the
attack was successful, (ii) the attack failed, or (iii) the
success or failure of the attack is undeterminable(Fig. 5). If the alert has information that indicates theattack was successful, the response priority is high,and the alert should be checked first, even if otheralerts are checked later. Conversely, if information isadded to the alert that the attack failed, the priority of
the response is low, and the alert could be checked
later. This technology makes it clear at a glance
which alerts should be prioritized, and we believe that
if a large event or forum suffers an increasing numberof alerts or if an attacker carries out a campaign, theeffect of alert-triage technology will be more pronounced.
According to our evaluation using a real network
environment, about 52% of alerts were correctly
judged as failed attacks, and the priority of responseto those alerts was reduced. Moreover, it was possible
to raise the priority of related critical alerts to just
0.1% of successful attacks lost in a large number ofalerts. An example of another favorable result is that
it was also possible to recognize an attack as success-NTT Technical Review

Vol. 18 No. 4 Apr. 2020

ful at the reconnaissance stage (at which the damage
was still minimal) and, by notifying the operator, totake measures before the attack damage spread.
7. Future developments
Under the supposition that it is practically difficult
to prevent cyberattacks in advance, a technology that
determines the success or failure of a malware infection at an endpoint terminal or an attack on a public
server—by focusing on the traces left during theattack—was introduced in this article. For future
work, we will advance our research on technology for
automating the response after detection of an attack
to counter cyberattacks—which are expected to
become increasingly sophisticated and numerous.
References
[1]

[2]

[3]

Y. Kurogome, Y. Otsuki, Y. Kawakoya, M. Iwamura, S. Hayashi, T.
Mori, and K. Sen, “EIGER: Automated IOC Generation for Accurate
and Interpretable Endpoint Malware Detection,” The Annual Computer Security Applications Conference (ACSAC) 2019, San Juan,
USA, Dec. 2019.
Y. Kanemoto, K. Aoki, J. Miyoshi, H. Shimada, and H. Takakura,“Detecting Successful Attacks against Web Application based-on
Attack Code Emulation,” IPSJ Journal, No. 60, Vol. 3, pp. 945–955,
2019 (in Japanese).
Y. Kanemoto, K. Aoki, M. Iwamura, J. Miyoshi, D. Kotani, H.
Takakura, and Y. Okabe, “Detecting Successful Attacks from IDS
Alerts Based on Emulation of Remote Shellcodes,” Proc. of the IEEE
Computer Society’s signature conference on Computers, Softwareand Applications (COMPSAC) 2019, Vol. 2, pp. 471–476, Milwaukee, USA, July 2019.

20

Feature Articles

Makoto Iwamura

Distinguished Researcher, NTT Secure Platform Laboratories.
He received a B.E., M.E., and D.Eng. in science and engineering from Waseda University,
Tokyo, in 2000, 2002, and 2012. He joined NTT
in 2002. He is currently with NTT Secure Platform Laboratories, where he is engaged in the
Cyber Security Project. His research interests
include reverse engineering, vulnerability discovery, and malware analysis.

Yo Kanemoto

Researcher, NTT Secure Platform Laboratories.
He received a B.E. and M.E. in information
science from Nagoya University in 2011 and2013. Since joining NTT in 2013, he has been
researching and developing network security
technologies.

Yuma Kurogome

Researcher, NTT Secure Platform Laboratories.
His research interest lies in both defensive andoffensive perspectives on malware, that is, malware detection/analysis and evasion. His major
research results were presented at industrial venues such as CODEBLUE’15 and Black Hat
Europe’19 Arsenal, and an academic paper for
ACSAC’19.

Yuhei Kawakoya

Distinguished Researcher, NTT Secure Platform Laboratories.
He received a B.E., M.E., and D.Eng. in science and engineering from Waseda University,
Tokyo, in 2003, 2005, and 2019. Since joining
NTT in 2005, he has been involved in computer
system security research. From 2013 to 2016, hewas engaged in R&D at NTT Innovation Institute, Inc., USA, as a software engineer. His
research interests include reverse engineering,
program obfuscation, malware analysis, andforensics.

Shingo Orihara

Senior Research Engineer, NTT Secure Platform Laboratories.
He received a B.E. and M.E. in information
science from Tohoku University, Miyagi, in 2001
and 2003. Since joining NTT in 2003, he has
been researching and developing network security technologies. His research interests include
security log analysis and cloud computing.

Jun Miyoshi

Senior Research Engineer, Supervisor, Cyber
Security Project, NTT Secure Platform Laboratories.
He received a B.E. and M.E. in system sciencefrom Kyoto University in 1993 and 1995. Sincejoining NTT in 1995, he has been researchingand developing network security technologies.
From 2011 to 2016, he was engaged in R&D
strategy management of NTT Secure Platform
Laboratories. He is currently a research groupleader of Cyber Security Project in the Laboratories. He is a member of the Institute of Electronics, Information and Communication Engineers(IEICE).

Kazufumi Aoki

Senior Research Engineer, NTT Secure Platform Laboratories.
He received a B.E. and M.E. in information
science from Tohoku University, Miyagi, in 2004
and 2006. Since joining NTT in 2006, he has
been researching and developing cybersecurity
technologies. His research interests include
reverse engineering and malware analysis.

NTT Technical Review

Vol. 18 No. 4 Apr. 202021

Feature Articles: Security Technologies for Creating
New Value

Cutting-edge Research on
Cryptography Theory in Response to
Changes in Computing Environments
Masayuki Abe, Yuuki Tokunaga, Mehdi Tibouchi,
Ryo Nishimaki, and Keita Xagawa
Abstract

Triggered by the case that a government employee successfully forged a bank card in 1982, NTTestablished the first research group on cryptography around the same time. NTT Secure Platform Laboratories has contributed to building a firm theoretical ground for cryptography while developing cryptographic technologies that can respond to the changes in evolving communication and computing
environments. In this article, research activities of NTT Secure Platform Laboratories on cryptography
and information security technologies—in preparation for the emergence of rapidly developing quantum
computers—are discussed.
Keywords: quantum computer, post-quantum cryptography, attribute-based encryption

1. BackgroundThe notion of security in cryptography is definedon the basis of the amount of computational resources(i.e., memory and computational speed) that an
attacker can have. In the 1990s, when the Internet
began to spread, a public key of Rivest–Shamir–
Adleman (RSA) encryption, having about 512 bits,
was considered secure. In 2001, when the Electronic
Signature Law was enacted in Japan, public keys are
required to be 1024 bits, and in the revision to thatlaw, which has been being considered since 2008,
they will soon be required to be at least 2048 bits.
Many cryptosystems are moving toward the more
efficient elliptic curve approach. More advanced public key cryptography (such as identity-based cryptography based on pairing groups over elliptic curves),
efficient digital signature schemes protecting privacyof the signer, and highly efficient non-interactive
zero-knowledge proof systems have been developed.
Cryptography naturally has the ability to control
access to information through key-management
methods. Regarding conventional cryptographic
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Vol. 18 No. 4 Apr. 2020

communication, the sender and receiver of information have a one-to-one relation. In the more complex
scenario of encrypted communication, however,encrypted data are stored in the cloud and the embedded information is accessible by multiple recipientssatisfying the condition specified by the sender. Someadvanced cryptosystems, such as attribute-based
encryption (ABE), have been developed for such purposes.
It has been shown that if a general-purpose quantum computer is developed that can handle a large
number of qubits with sufficient precision so that
Shor’s algorithm can be executed, it will be able tobreak efficient public-key cryptographic schemes,such as RSA encryption and Diffie–Hellman key
exchange, currently in wide use [1]. Even if such
advanced quantum computers do not become viable
for several decades, it is necessary to develop cryptographic techniques that are secure against the threatsuch computers pose—so-called post-quantum cryptography—without waiting for quantum computers
to become a reality. In fact, much research and development (R&D) and standardization of post-quantum
22Feature Articles

cryptography is already underway. As well as the
motive of the providers of cryptographic systems,
there are two practical reasons for such effort. The
first is that a new encryption method takes a very longtime from development to deployment in the realworld. That is, updating a system that appears to beworking to a new system that is not compatible is not
something that every user can do in a short time. The
other reason is the concern that current privacy will
be compromised by future advances in attack techniques in a manner called long-term security compromise. It is a concern that even encrypted communications may be intercepted and stored for long periods,
and their content may be exposed by quantum computers created in the future. In other words, for content that would be difficult to leak after several
decades, a quantum-computer attack is a threat thatmust be addressed in the present. Post-quantum cryptography is not executed on a quantum computer;
instead, it is executed on current computers. It istherefore necessary to consider security in terms of
post-quantum cryptography in the current computer
environment.
The activities of NTT Secure Platform Laboratories(SC Labs) regarding quantum information processing
technology are first described. The latest topics concerning post-quantum cryptography are then discussed. Finally, SC Labs’ latest research results on
ABE, which is one of the functions of conventional
public-key cryptography, are presented.
2. Quantum information processing
2.1 Q uantum information processing technology
at SC Labs
In October 2019, news circulated that quantum
computers had finally achieved “quantum supremacy,” namely, capabilities beyond those of conventional computers [2]. SC Labs has been researchingand developing quantum computers that process
information on the basis of the principles of quantum
mechanics.
Quantum computers implemented to date can still
only process data on the order of tens of qubits, andmany issues on how to achieve scalability remainunresolved. In other words, R&D on how to constructquantum computers and achieve scalability is the litmus test for verifying the current security level ofcryptography. Quantum information technology has
also created new security technologies. The properties of quantum states differ from those of ordinary
data, for example, a state is destroyed when measured
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Vol. 18 No. 4 Apr. 2020

unnecessarily, and it cannot be copied. By making
good use of these different properties, new security
technologies can be developed.
2.2 Path to developing the quantum computer
The foremost barrier to constructing quantum computers is their vulnerability to errors. Regarding
qubits, it is difficult to reduce errors in the manner ofdigital data, which is the main information-processing unit used today; accordingly, if the scale of aquantum computer is increased, the computational
result will be buried in the noise, and correct calculation will become difficult. The only solution to thisproblem thus far has been quantum error correction.
When quantum error correction is applied, if the control of qubits is achieved below a specific error rate
within a technically feasible range, the logical error
rate of the quantum information in the encoded quantum state can be reduced, and the handling capabilityof the error can be extended.
Another issue is to increase the size of the qubit.
Increasing the scale of qubits while accurately controlling individual qubits at high speed is contradictory and has rarely been achieved with unstable
quantum states. A breakthrough in quantum engineering is expected to increase the number of qubits
while maintaining accuracy of controlling individual
qubits. At SC Labs, we (a subgroup) are participatingin the Ministry of Education, Culture, Sports, Scienceand Technology (MEXT)’s Q-LEAP project, which is
involved in the development of superconducting
quantum computers. As part of Q-LEAP, we areworking on advanced control technology that enables
quantum error correction and R&D aiming at expanding the scale of quantum computers.
3. Toward quantum-secure networks
An example of a new security technology that uses
quantum information processing is quantum cryptography (or quantum key distribution). Eavesdropping
can be detected if the quantum state is destroyedwhen measured unnecessarily, so, secure key distribution is possible in principle. However, there arethree problems with the current technology: (i) vulnerability to loss, (ii) practically limited communication distance (up to about 100 km), and (iii) inabilityof networking. The solution to these problems isusing a quantum repeater, which makes it possible tocontrol quantum states of light and matter with highprecision and to correct quantum errors in a mannerthat can withstand losses. In fact, a quantum repeater
23

Feature Articles

is therefore a technology that is fairly comparablewith constructing small to medium-scale quantum
computers. To implement a quantum repeater, wehave to conduct almost the same R&D as that for
implementing quantum computers. At SC Labs, we
are working on controlling the quantum states of lightand atoms with the high precision required for quantum repeaters while increasing the scale of the quantum states that can be handled. SC Labs is also participating in the CREST project of the Japan Scienceand Technology Agency (JST), in which we areengaged in R&D using cavity quantum electrodynamics—which enables high-precision interaction
between light and atoms.
4. Toward quantum-resistant (post-quantum)
cryptography: Secure implementation andcontribution to standardization
In addition to conventional cryptographic techniques such as RSA cryptography and elliptic-curve
cryptography, post-quantum cryptography, which isconsidered to be durable against quantum cryptography, has been studied for decades. For the most basic
functions, namely, encryption and signature schemes,
theoretical schemes based on problems that are difficult to solve with quantum computers have been
known for a long time. However, the performance of
these schemes, such as processing speed and communication traffic, is remarkably inferior to that of
RSA cryptography and elliptic-curve cryptography,
so these schemes have been determined impractical,
and implementations of post-quantum cryptography
are scarce.
As the emergence of quantum computers has
recently become a visible threat, this threat has finally started to be seriously considered. Proposing andimplementing faster and higher-performance postquantum-cryptography technologies have become
important research topics. In particular, in latticebased cryptography, which is regarded as promisingfor post-quantum cryptography, new schemes havebeen proposed and implemented by adding several
ideas and optimizations to conventional schemes thathave strong security foundations, and they have demonstrated performance comparable to that of RSA
encryption. Implementation experiments on virtualprivate network software have also begun [3].
While theoretical security foundations have beenthoroughly investigated, vulnerabilities concerning
implementation (such as side-channel attacks andfault attacks) have not been considered. Moreover,
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efficient new schemes often require sampling fromdiscrete Gaussians distributions and rejection sampling, which are not used in the conventional cryptographic schemes; thus, secure implementations ofthem are new challenges. To address these implementation issues, SC Labs assessed security against
implementation attacks, especially against the latticebased signature scheme, and discovered numerous
vulnerabilities [4, 5, 6, 7, 8]. For example, in a previous study [4], which targeted multiple implementations of the BLISS scheme, a fast lattice-based signature, we showed that measuring power consumption
and processing time when a signature is generated
makes it possible to completely recover the secret key
by using algebra and number theory. We are proposing countermeasures and implementation schemes toovercome the above-mentioned vulnerabilities andare verifying their security. We also proposed andimplemented lattice-based signature schemes thatprovide strong security against implementation
attacks while maintaining the highest level of performance [9, 10, 11].
The above-mentioned studies had a significant
impact on the ongoing post-quantum cryptography
standardization process launched by the National
Institute of Standards and Technology (NIST) in
2016 (hereafter, NIST Post-Quantum Cryptography(PQC) standardization). In particular, the implementation vulnerabilities of the BLISS scheme [4] arebeing considered as implementation threats in thedesign policy of a candidate called Dilithium.
According to reported results [4], almost all latticebased signatures in the NIST PQC standardization
avoided sampling from discrete Gaussian distribution. Even after the start of the NIST PQC standardization, SC Labs contributed to the successful results
regarding safe implementation of Dilithium and Falcon [6, 8, 10, 11] and to completely defeating andeliminating a scheme with weak security foundations[12].
5. Recent topic 1: Quantum computersand cryptography
 ethod for evaluating security of symmetric5.1 M
key cryptography using a quantum computer
A general-purpose quantum algorithm for secretkey cryptography is not currently known. Therefore,
attacks that apply the Grover algorithm or the quantum-random-walk algorithm are known to be best. At
SC Labs, we developed methods for evaluating security based on analyzing the internal details of24

Feature Articles

symmetric-key cryptographic schemes. For example,
we improved the multi-collision-finding algorithm ofhash functions, which was achieved in collaboration
with NTT Communication Science Laboratories[13].
Furthermore, anticipating the availability of quantum computers in the future, some adversaries may be
now eavesdropping and collecting information. We
are also devising safety-assessment methods for estimating the effect of such adversaries [14, 15].
5.2 T echnique for security proofs in the presenceof quantum computers
Many previous security proofs did not assume thatan adversary has a quantum computer. As a result,even if the security is proven, there is a chance thatthe adversary can breach the security by using a quantum computer. Under such a circumstance, many
security-proof techniques that take into accountquantum computers have been developed since 2010.
SC Labs is also researching such security proofs.
Some examples of this research are methods forenhancing the security of post-quantum public-key
cryptography [16, 17], quantum security of hashfunctions [18], quantum security of symmetric-key
cryptography with the Feistel structure [19], and general lower-bound evaluation of attacks on hash functions when precomputation is allowed [20].

are determined at the initialization of a system, that is,
we can thereafter no longer add attributes. To attainscalability, it is desirable to be able to add attributes
at any time. Another problem is data size. In the caseof some methods, the size of the ciphertext increases
in proportion to the size of the embedded policy andnumber of attributes used. This dependence has been
undesirable because it occupies storage. Therefore,various performance criteria have been considered inregard to actual use; however, an ABE scheme thatreaches practically desirable levels in relation to all
those criteria had not yet been proposed. Given thissituation, we developed an ABE scheme that possesses all the properties desirable in terms of practicality.
References[1][2]

6. Recent topic 2: ABE
Although public-key cryptography can be divided
into several main themes, this article focuses on one,
attribute-based cryptography with practical efficiency. For public-key cryptography, a sender of information encrypts the information with a recipient’s public
key into a ciphertext and only the recipient who has
the corresponding private key can decipher the
ciphertext to access the information. ABE schemes
allow the sender to freely specify the recipient without limiting the information to a single recipient.
More specifically, a policy is embedded in the ciphertext, and attributes of the recipient are embedded in
the secret key. A recipient can then receive information only if their attributes match the policy in the
ciphertext. Therefore, the logic is embedded in the
ciphertext and secret key, and it is possible to restrict
information exchange.
Many ABE schemes have been proposed; nevertheless, they are insufficient in terms of implementing
them in actual systems. One problem is scalability of
attributes. Many ABEs require that all attributes used
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Vol. 18 No. 4 Apr. 2020

[3]
[4]

[5]

[6]
[7]

[8]

[9]

P. W. Shor, “Polynomial-time Algorithms for Prime Factorization andDiscrete Logarithms on a Quantum Computer,” SIAM J. Comput.,Vol. 26, No. 5, pp. 1484–1509, 1997.
F. Arute, K. Arya, R. Babbush, D. Bacon, J. C. Bardin, R. Barends, R.
Biswas, S. Boixo, F. G. S. L. Brandao, D. A. Buell, B. Burkett, Y.
Chen, Z. Chen, B. Chiaro, R. Collins, W. Courtney, A. Dunsworth, E.
Farhi, B. Foxen, A. Fowler, C. Gidney, M. Giustina, R. Graff, K.
Guerin, S. Habegger, M. P. Harrigan, M. J. Hartmann, A. Ho, M.
Hoffmann, T. Huang, T. S. Humble, S. V. Isakov, E. Jeffrey, Z. Jiang,
D. Kafri, K. Kechedzhi, J. Kelly, P. V. Klimov, S. Knysh, A. Korotkov,
F. Kostritsa, D. Landhuis, M. Lindmark, E. Lucero, D. Lyakh, S.
Mandrà, J. R. McClean, M. McEwen, A. Megrant, X. Mi, K. Michielsen, M. Mohseni, J. Mutus, O. Naaman, M. Neeley, C. Neill, M. Y.
Niu, E. Ostby, A. Petukhov, J. C. Platt, C. Quintana, E. G. Rieffel, P.
Roushan, N. C. Rubin, D. Sank, K. J. Satzinger, V. Smelyanskiy, K. J.
Sung, M. D. Trevithick, A. Vainsencher, B. Villalonga, T. White, Z. J.
Yao, P. Yeh, A. Zalcman, H. Neven, and J. M. Martinis, “Quantum
Supremacy Using a Programmable Superconducting Processor,”
Nature, Vol. 574, pp. 505–510, 2019.
Post-quantum Cryptography VPN, https://github.com/Microsoft/
PQCrypto-VPN
T. Espitau, P.-A. Fouque, B. Gerard, and M. Tibouchi, “Side-channel
Attacks on BLISS Lattice-based Signatures: Exploiting Branch Tracing against strongSwan and Electromagnetic Emanations in Microcontrollers,” Proc. of the 2017 ACM SIGSAC Conference on Computer and Communications Security (CCS), pp. 1857–1874, Dallas,
Texas, USA, Oct. 2017.
J. Bootle, C. Delaplace, T. Espitau, P.-A. Fouque, and M. Tibouchi,“LWE Without Modular Reduction and Improved Side-channel
Attacks against BLISS,” Advances in Cryptology, ASIACRYPT 2018,
LNCS, Vol. 11272, pp. 494–524, Springer, 2018.
T. Espitau, P.-A. Fouque, B. Gérard, and M. Tibouchi, “Loop-abort
Faults on Lattice-based Signature Schemes and Key Exchange Protocols,” IEEE Trans. Comput., Vol. 67, No. 11, pp. 1535–1549, 2018.
M. Tibouchi and A. Wallet, “One Bit Is All It Takes: A Devastating
Timing Attack on BLISS’s Non-constant Time Sign Flips,” Journal of
Mathematical Cryptology, Special Issue on MathCrypt 2019, De
Gruyter, to appear.
P.-A. Fouque, P. Kirchner, M. Tibouchi, A. Wallet, and Y. Yu, “Uprooting the Falcon Tree?: How to Recover Secret Keys from GramSchmidt Norms,” IACR Cryptology ePrint Archive, Report
2019/1180, 2019.
G. Barthe, S. Belaïd, T. Espitau, P.-A. Fouque, B. Grégoire, M. Rossi,
and M. Tibouchi, “Masking the GLP Lattice-based Signature Scheme
at Any Order,” Advances in Cryptology – EUROCRYPT 2018, LNCS,

25

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Vol. 10821, pp. 354–384, Springer, 2018.
[10] P.-A. Fouque, B. Gérard, V. Migliore, and M. Tibouchi, “Masking
Dilithium: Efficient Implementation and Side-channel Evaluation,”
Applied Cryptography and Network Security, ACNS 2019, LNCS,
Vol. 11464, pp. 344–362, Springer, 2019.
[11] G. Barthe, S. Belaid, T. Espitau, P.-A. Fouque, M. Rossi, and M.
Tibouchi, “GALACTICS: Gaussian Sampling for Lattice-based Constant-time Implementation of Cryptographic Signatures, Revisited,”
Proc. of ACM CCS 2019, pp. 2147–2164, London, UK, Nov. 2019.
[12] J. Bootle, M. Tibouchi, and K. Xagawa, “Cryptanalysis of CompactLWE,” Topics in Cryptology – CT-RSA 2018, LNCS, Vol. 10808, pp.
80–97, Springer, 2018.
[13] A. Hosoyamada, Y. Sasaki, S. Tani, and K. Xagawa, “Improved Quantum Multicollision-finding Algorithm,” Post-Quantum Cryptography,
PQCrypto 2019, LNCS, Vol. 11505, pp. 350–367, Springer, 2019.
[14] A. Hosoyamada and Y. Sasaki, “Cryptanalysis against Symmetric-key
Schemes with Online Classical Queries and Offline Quantum Computations,” Topics in Cryptology, CT-RSA 2018, LNCS, Vol. 10808, pp.
198–218, Springer, 2018.
[15] X. Bonnetain, A. Hosoyamada, M. Naya-Plasencia, Y. Sasaki, and A.
Schrottenloher, “Quantum Attacks without Superposition Queries:

Masayuki Abe

The Offline Simon’s Algorithm,” Advances in Cryptology, ASIACRYPT 2019, LNCS, Vol. 11921, pp 552–583, Springer, 2019.
[16] T. Saito, K. Xagawa, and T. Yamakawa, “Tightly-secure Key-encapsulation Mechanism in the Quantum Random Oracle Model,” Advancesin Cryptology, EUROCRYPT 2018, Part III, LNCS, Vol. 10822, pp.
520–551, 2018.
[17] K. Xagawa and T. Yamakawa, “(Tightly) QCCA-secure Key-encapsulation Mechanism in the Quantum Random Oracle Model,” PostQuantum Cryptography, PQCrypto 2019, LNCS, Vol. 11505, pp.
249–268, Springer, 2019.
[18] A. Hosoyamada and K. Yasuda, “Building Quantum-one-way Functions from Block Ciphers: Davies-Meyer and Merkle-Damgård Constructions,” Advances in Cryptology, ASIACRYPT 2018, Part I,
LNCS, Vol. 11272, pp. 275–304, 2018.
[19] A. Hosoyamada and T. Iwata, “4-Round Luby-Rackoff Construction
is a qPRP,” Advances in Cryptology, ASIACRYPT 2019, LNCS, Vol.
11921, pp. 145–174, Springer, 2019.
[20] M. Hhan, K. Xagawa, and T. Yamakawa, “Quantum Random Oracle
Model with Auxiliary Input,” Advances in Cryptology, ASIACRYPT
2019, LNCS, Vol. 11921, pp 584–614, Springer, 2019.

Ryo Nishimaki

Senior Distinguished Researcher, NTT Secure
Platform Laboratories.
He received a Ph.D. from the University ofTokyo in 2002 and has been at NTT since 1992.
Currently, he is a senior distinguished researchscientist at NTT Secure Platform Laboratories.
He served as a program chair for CT-RSA’07,
ACM ASIACCS’08, and Asiacrypt’10. His
research interests include digital signatures,
public-key encryption, and efficient instantiationof cryptographic protocols.

Distinguished Researcher, Data Security Project, NTT Secure Platform Laboratories.
He received a B.E. and M.I. from Kyoto University and a D.S. from Tokyo Institute of Technology in 2005, 2007, and 2010. He joined NTT
in 2007, where he has been focusing on design
and foundation of cryptography. He is currently
researching cryptography and information security at NTT Secure Platform Laboratories.

Yuuki Tokunaga

Keita Xagawa

Distinguished Researcher, NTT Secure Platform Laboratories.
He received a Ph.D. in science from Osaka
University in 2007. He joined NTT in 2001,
where he has been conducting research toward
the realization of fault-tolerant universal quantum computing and long-distance secure quantum network.

Scientist, NTT Secure Platform Laboratories.
He received a B.S. from Kyoto University andan M.S. and D.S. from Tokyo Institute of Technology in 2005, 2007, and 2010. He joined NTT
in 2010, where he has been focusing on algebraic
algorithms and provable security in cryptography. He is currently researching cryptography
and information security at NTT Secure Platform
Laboratories.

Mehdi Tibouchi

Distinguished Researcher, NTT Secure Platform Laboratories.
An alumni of The École Normale Supérieure,
Paris, France. He joined NTT in 2011 after
obtaining his Ph.D. in computer science from
Univ. Paris VII and Univ. Luxembourg. He iscurrently a distinguished researcher at NTT
Secure Platform Laboratories. His research interests cover various mathematical aspects of public-key cryptography and cryptanalysis.

NTT Technical Review

Vol. 18 No. 4 Apr. 202026

Feature Articles: Keynote Speeches/Workshop
Lectures at Tsukuba Forum 2019

Working toward Sharing Social
Infrastructure
Motoyuki Ii
Abstract

This article introduces initiatives for sharing the social infrastructure
within the NTT Group, including concrete measures to resolve societal
issues and other initiatives. It was prepared based on a keynote speech
given by NTT Senior Executive Vice President Motoyuki Ii at the Tsukuba Forum 2019 held on October 31 and November 1, 2019.
Keywords: sharing of social infrastructure, smart infrastructure, smart
energy1. Introduction
As human economic development has progressed,
the burden on the environment has continued toincrease. With advances in information and communication technology (ICT), increasing amounts ofenergy and resources are being consumed. The NTT
Group has an obligation to work actively on reducing
this burden on the environment while also contributing to economic development (Fig. 1). Three key
points in this area are that (1) the NTT Group overall
must change its mindset; (2) the NTT Group mustshow these changes by concrete action; and (3) technical innovation will support this action. These threepoints form the basis for this lecture.
The main economic model has been linear economy, in which products are made from materials, soldand used, then discarded. Taking automobiles as an
example, the number of cars has increased as the
economy brought prosperity, going from one car per
household to one car per person. As a result, we areusing more materials and energy, building moreroads, and continuously increasing the load on theenvironment. The same applies to home appliances.
As people have become richer, households have airconditioners and several televisions. The situation is
the same in our field, i.e., ICT. As ICT becomes moreabundant, the amount of information being circulated
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Vol. 18 No. 4 Apr. 2020

increases, and the amount of energy needed increases. Such activity is definitely not environmentallyfriendly. However, life is more convenient, and society is safer and more secure. So what approaches are
there to reducing the burden on the environment?
1.1 Circular economy
The idea of the circular economy is now consideredobvious in Europe, particularly in the Netherlands.
This is a recycling-based economic system; re-using
items or returning them to usable base materials. If
that is not possible, then burning them to produce
energy. We need to adopt technology to reduce theload on the environment and develop the economy byproviding things as services and not owning them, or
sharing them and not having exclusive ownership.
Companies and private citizens will need to work
toward a circular economy, sharing rather than owning assets, and using as many renewable sources ofenergy as possible (Fig. 2).
1.2 Peer-to-Peer (P2P) sharing economy
The P2P sharing economy is being advanced mainly by individuals. More people register to provide
services in various categories, and users can use these
services without owning anything. Such an economy
has begun in many sectors of society, and re-using
things and using renewable resources are advancing.
27

Environmental burden

Feature Articles

Heavy burden
on theenvironmentToday
If this continues…
Paradigm shift

Industry
Agriculture
Hunting

Targetposition

Economic scaleFig. 1. Achieving both economic development and reduced environmental load.

Resources

Production

Procurement

Renewable energy
Recycling
Disposal

Use

Sharing

Sales

Technical innovation

Circular economy: sharing, recycling
Economy with cycles of “manufacture, sales, use, re-use”
Use of renewable energy and technological innovation

Fig. 2. Economic model for the future.

The background to this sharing economy is, ofcourse, sharing rather than owning. A value is emerging that it is better to share with everyone because it
is a waste to throw things away, and an economy isemerging in which buyers and sellers can trade oneto-one, immediately and every day. However, in theprevalent model in the field of communications,facilities, such as antennas, conduits, and power supplies, are equated with services, which has led providers to exclusively own facilities. In the mobile
communications field, the ability to install antennas
in good locations is an advantage for companies, so
there is a tendency for companies to install them insimilar locations. We argue that competition regarding facilities and services are the same, but this has
increased the burden on the environment. We will
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need to change this approach by separating facilities
and services, sharing as many facilities as possible,and competing in terms of services (Fig. 3).
1.3 Sharing social infrastructure in ICTWhat does the social infrastructure mean in ICT? A
social infrastructure is defined to include facilities
such as antennas, conduits, and power supplies fortelecommunication companies. Physical equipment,such as computers, servers, and storage, and evendata in cloud technology are included. To share theseassets, they must be created and used jointly, or madeopen and used in a reciprocal manner. Therefore, socalled infrastructure sharing must be considered toinclude the use of data (Fig. 4). If our efforts thus far
have been egocentric, our mindset needs to be28

Feature Articles

Increase efficiency, eliminate wasteby sharing facilities (infrastructure)

FutureCustomers

Move from competition in terms offacilities to in terms of services.

Model separating
facilities and services

Paradigm shift
Targetposition

Services
Reduceenvironmental burden
Facilities

Minimize costs

Effective use of social capital and resources

Fig. 3. Sharing economy.

Socialinfrastructure

Sharing

Antennas, conduits, power, etc.

Joint construction

Use of existing facilities:
Everyone can use whatalready exists

Data

Use of existing facilities

Joint construction:
Build required
facilities together

Open

Open:
Share and use eachothers’ data

Fig. 4. Shared use of social infrastructure in ICT.

changed to be eco-centric, moving from a linear
economy to a circular economy, and from owning tosharing at the business level.
2. Concrete initiatives at NTT
The NTT Group has qualities of both a public andprivate organization, and is required to bear some
responsibility toward society as a whole. To find solutions for various issues in society through our business activities, we need to collaborate with partners.
As a result, we are oriented toward forming a smart
world, or Society 5.0, as it is being called in Japan,
and to contribute to the United Nations’ Sustainable
Development Goals (SDGs). Below we introduce ourthree businesses working toward such collaboration:
Mobile Communications, Smart Infrastructure, and
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Vol. 18 No. 4 Apr. 2020

Smart Energy.
2.1 Mobile Communications businessSocial issues in this business are reducing the capital cost of facilities, accelerating infrastructure building for national deployment of fifth-generation
mobile communication systems (5G), and securing
space to build 5G base stations. Our theme is, “Do wereally still need to compete in terms of facilities inthese areas?” Would it not be better to share as much
infrastructure as possible, reduce costs, and use
space, which is a societal resource, more effectively?
(1) Building sharing (indoor/outdoor)
JTOWER is a company that is neutral with respect
to mobile carriers, and is working to build antennas
collaboratively. As a pure holding company, NTT has
investment and business ties with JTOWER. This is29

Feature Articles

Implement low-latency processing functions at the antenna to reduce constraints on distance tobase-station equipment
Use various buildings effectively to reduce concentration of base-station equipment on particular buildings
Ensure reliability of lines to distant buildings with loops or other redundant configurations
Base-station equipment
Company B
Company C

Base-stationequipment

Company D

Reduce constraintsof distanceCompany A

Increase flexibility
in locations to installequipment

Base-station equipment

Base-station equipment

Fig. 5. Promoting building sharing.

the first step. We would like to expand the sharing
model and overcome barriers among mobile carriersin the 5G era.
As 5G is introduced into buildings, factories, andother workplaces, construction of many antennas inbuildings will be necessary. If every company does
this, the number of antennas, cabling, power supplies,
and other facilities will be unwieldy. This has led toinitiatives toward in-building system (IBS) sharing tosimplify and share antennas and other facilities, atleast within buildings. This would help reduce costs
and energy consumption. There will be a need forneutral companies to carry such efforts into the
future. In particular, JTOWER is working with tenants, shopping malls, and other commercial buildingson IBS sharing. Since companies are building theirown separate antennas, integration of these facilities
is necessary.
There is also increasing need to build 5G antennas
outside (towers). Density is lower in rural areas, so
5G business would not be profitable, while sharing
business will have great financial significance. In
urban areas, there is little space for building facilities,
so it makes sense to share the small available space.
Even if JTOWER does not build all facilities, it would
be beneficial for carriers to open access to their own
towers and other facilities. When 5G frequencies
were first allocated, the Ministry of Internal Affairs
and Communications (MIC) divided Japan into amesh of approximately 4500 10-km2 sections. Each
carrier was asked what percentage of these sections
they would cover by 2024, and the requested frequency allocations were granted giving priority to
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

carriers that declared to provide 5G services covering
more of these sections. Four carriers overlapped inmost of these approximately 4500 sections, so we
believe that it will be an issue whether these carriers
will have separate facilities or share facilities.
Each company is also currently building their own
mobile front-haul (MFH), which connects base stations to each of their antennas, and mobile back-haul(MBH), which connects base stations and base stations to their core communications networks. We
would like to share these facilities in the future. However, for the MFH, dark fiber is used to send radiofrequency signals between base stations and antennas. If technical innovation produces a low-latencytransmission scheme, it will be possible to overcome
constraints on distances to base stations and bringsignals to neighboring buildings. This will allow
base-station equipment to be installed in various
buildings, contributing to sharing buildings and using
them more effectively. If such networks can be given
loop topology, redundancy will also increase. As
building resources are limited, it will be necessary to
promote building sharing by sharing and introducing
new technologies, which requires technical innovation (Fig. 5).
(2)	Promoting interoperability of base-stationequipment
The Open Radio Access Network (O-RAN) Alliance is an industry consortium gathering carriers andvendors from around the world. Until now, vendors
have built base-station equipment using their own
interfaces, creating an environment in which productsof a company can only be connected with each other.
30

Feature Articles

End-to-end links by combining ICT resources
Network service

API

Ctrl

Business A

Ctrl
Business C

Business B

API

Ctrl

API

Ctrl

All-Photonics Network
Transport

Public network

Optical processor(opto-electronic
integration)

Agent
DeviceSocietal system provision

Ctrl

Wholesale provision

Edge

Cloud

Ctrl
API

API

Service provision

DigitalTwin Computing

Overlay solutions

Multi-orchestrator

Rapid deployment of ICT resources andoptimization of configurations

Service provider operating societal systems

Private network

Customers

API: application programming interface
Ctrl: controller

Fig. 6. Vision of future networks.

This has made sharing difficult, so the O-RAN Alliance is defining open interfaces. For the next stage,
Advanced 5G, if vendors make their products basedon open interfaces, a testbed will be prepared tocheck these interfaces and interconnectivity andinteroperability can be checked with each product,
there will be an environment in which products fromdifferent vendors can co-exist. This kind of initiative
will contribute to sharing.
(3) Vision for networks in the future
A three-layer model (Fig. 6) describes network
issues. The bottom layer is the transport layer, consisting of communication media such as fiber or wireless. The middle layer is the network-service layer,
provided by each carrier providing various services tocustomers. The top layer contains overlay solutions,creating various services using the cloud. For example, services created by GAFA (Google, Apple, Facebook, and Amazon) are at this layer. Actual services
are provided by combining network resources withoverlay-solution resources using multi-orchestration.
Note that “sharing,” as we mentioned so far, applies
to the most basic transport layer, including antennas
and transmission channels. However, service competition will occur in the top overlay-solution layer. We
can provide new value to users by combining sharing
NTT Technical Review

Vol. 18 No. 4 Apr. 2020and competition.
2.2 Smart Infrastructure business
By infrastructure, we refer to underground facilities
such as conduits and cable tunnels, and the related
data. The underground facilities of service providers,such as those for gas, water, and electricity, as well as
communication, have become very old. Personnel
who build and maintain such facilities are also getting
older, and facilities are managed separately by eachcompany. This is inefficient and places an extra burden on the environment. Such conditions have led tothe idea of smart infrastructure, in which companies
can share data and find various efficiencies that can
reduce the burden on the environment, even if they do
not share all their facilities. To achieve this, it will benecessary to layer databases of the facilities held by
each company on a single map. Companies do notknow what facilities others have or what is buried ata certain depth. They each carry out work, such as
digging up roadways, at different times. The firstrequirement is therefore to share the data. The data
must be opened, and all facilities must be made visible based on this open data. A platform to accomplish
this is needed. When real facilities are converted todigital data and used to layer the digital world over31

Feature Articles

Smart infrastructure platform
Overallmanagementof time Communication(past to future)
Electricity
Gas
Water

Construction
site(coordinating
facilities locations)

3D spatial information

Precision positioning
information platform (3Dxt)

Electricity

Gas

Water

Triple IP
NTT Group asset

3D

Facilities/maintenance information

Electricity
Water
Gas

Central observer withaccurate information

Other
company DX

M data by
Map
NTT GEOSPACE

ManholeNTT

FutureOwn
company DX
co

MMS

Smart infrastructure business

Digital twin

BIM
CIM

SafetyWarnings
DangerPlan maintenanceefforts based on predictions of deterioration

Design cities in collaboration
with urban planning

Share infrastructure information, use as digital twins.
BIM: building information model
CIM: construction information modeling/management
DX: digital transformation

IP: Internet protocol
MMS: mobile mapping system
3Dxt: 3D xenon transientFig. 7. Smart infrastructure concept.

the real, it is called a digital twin. The success of thiseffort will depend on the quality of digital twin creation to reveal how the facilities are deployed underground. This will require three-dimensional (3D)
technology, prediction technology, and so on. Achieving such a system will enable companies to coordinate to build and maintain underground facilities,
rather than doing it separately as they have been(Fig. 7). For example, when repairing a road, a database will enable the repair work to be observed centrally by representatives from a different company.
Currently, an initiative is being promoted called
i-Construction, in which excavation equipment is
operated based on data regarding objects buried at thesite. Assuming the data are correct, this will help
avoid incidents such as accidental cutting of service
lines. We expect that the time is coming when it will
be standard to simulate work in cyberspace before
working in the real world.
Maintenance has been conducted by replacing
components based on fault criteria such as inspections or years of service life. By digitizing facility
information, prediction technologies can be used to
predict what will occur based on the data, potentiallyreducing the need for inspections (Fig. 8). We feelthat if companies having a societal infrastructure,such as communications cables, gas and water lines,
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

or electrical conduits, are able to conduct work onthem efficiently by coordinating with each other insome way, it would lessen environmental burden. To
achieve this, NTT changed the ownership of NTT
InfraNet from NTT EAST to our holding company,changed the management structure, and increased
capitalization to conduct a smart maintenance business and build a database, as described above, for the
NTT Group and for other companies. This was our
first initiative. When building smart cities, operatorsand the types of pipes and wiring will be decided in
the design stages, and it will be possible to examine
entire urban areas in cyberspace, including aspects
such as scenery.
2.3 Smart Energy businessCommunications and energy are inextricably
linked. We feel a great responsibility as a communications operator and have been developing ICT rapidly and are continuing to build datacenters, thus
dramatically increasing energy consumption. We
have our own initiatives to reduce the burden on theenvironment by supporting efforts to shift from using
fossil fuels to renewable energy sources. There havealso been repeated large-scale disasters recently,
which have damaged communications and other societal infrastructures worldwide. Providing emergency
32

Now

Previously

Feature Articles

Maintenanceafter the fact

Change or repair when a fault occurs

Preventative maintenance(time-based maintenance: TBM)

Change periodically based on equipment service life

Preventative maintenance(condition-based maintenance: CBM)

Replace or repair items beyond an inspection standard

FutureCollect inspection data, environment data, anduse artificial intelligence (AI) to predict the future.
Predictive maintenance(Beyond CBM)

MMS
Drones
3D scanners
Sensors

AI
Past to present

Estimate
optimalmaintenancetimes

Fig. 8. Utilization for smart maintenance.

power supplies at such times is becoming an important issue. To find solutions to such societal issues, wehave created a new subsidiary called NTT AnodeEnergy Corporation to share NTT’s communications
infrastructure and buildings (central offices) and contribute to building a sustainable society.
Currently, only 16% of the energy used in Japan isrenewable, and even for 2030 targets, we have given
only relatively passive figures of 22 to 24%. There arecountries in Europe achieving this in the 30% range,and some are declaring that they will increase thisrate to over 40%. It will be difficult to achieve 100%
renewable energy, but increasing this amount is necessary.
However, renewable energy has its weaknesses
compared with fossil fuel or nuclear power generation. For example, the amount of power generated
from solar power fluctuates greatly depending on theweather. Wind power is similarly unstable, varying
with the strength of the wind. There are also issues
with supply and demand. Urban areas have very highdemand for electrical power, but rural areas haveenvironments that can actually supply renewableenergy, while themselves consuming less electricity.
This balance of supply and demand has not beenachieved, and connecting everything with power lines
would be costly, even for just transmission and distribution lines. A mechanism to maximize the utilization of renewable energy is needed. One solution is
distributed energy. The supply-and-demand balanceissue can be resolved to a certain extent by consuming the energy near where it is generated. In many

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

regions, renewable energy has been introduced as a
backup for alternating current (AC) power, but when
there is sufficient AC power available, this produces
excess supply, so power generation is stopped. It
would be good if the excess could be stored in batteries and used when needed. However, such initiatives
are not currently being undertaken, and in reality, all
the renewable energy that could be generated is not
being used. We will need to somehow overlay therenewable-energy distributed-energy system on theexisting AC power system and maximize utilizationof renewable energy.
Some possibilities in such situations include placing batteries in the many buildings owned by NTT or
possibly building DC (direct current) transmission
and distribution networks though the conduits that we
also have between buildings. Communication operators are also well situated to show expertise in controlling and managing the energy network. ICT technology will be needed for controlling supply anddemand such as electricity discharge/generation
management and visualization. This will need to be
automated and autonomized with artificial intelligence, using appropriate triggers.
3. Conclusion
The NTT Group will continue in its efforts towarda sustainable environment, and we hope everyone
involved will support and collaborate with us in these
efforts.

33

Feature Articles

Motoyuki Ii

Senior Executive Vice President, NTT.
He received an M.S. in engineering from Keio University, Kanagawa, in 1983 andjoined Nippon Telegraph and Telephone Public Corporation (now NTT) the same
year. In June 2011, he became senior vice president of NTT EAST and executive
manager of the Plant Planning and Strategy Planning Departments of the Network
Business Headquarters. In June 2014, he became senior vice president of NTT
EAST and senior executive manager of the Corporate Sales Promotion Headquarters. In June 2015, he became executive vice president and representative director of
NTT EAST. In June 2016, he became its senior executive vice president. In July
2017, he became senior executive vice president and representative director of theBusiness Innovation Headquarters. In June 2018, he became senior executive vicepresident, chief technology officer, and chief information officer of NTT. In June
2019, he reached his current position as senior executive vice president of NTT.
In June 2000, he completed the Master of Science in Management course at Stanford Graduate School of Business, USA.

NTT Technical Review

Vol. 18 No. 4 Apr. 202034

Feature Articles: Keynote Speeches/Workshop
Lectures at Tsukuba Forum 2019

Pioneering a Prosperous Future with
Regional Innovations
Naoki Shibutani
Abstract

This article introduces the NTT EAST Group’s latest efforts in agriculture to make Japan more prosperous through the revitalization of small andmedium-sized enterprises and primary industries in Japan’s regions. It also
introduces the importance of collective impact in creating new value with avariety of stakeholders and a concept for creating an open social platform.
This article is an edited version of the keynote speech given by NTT EAST
Senior Executive Vice President Naoki Shibutani at Tsukuba Forum 2019,held on October 31 and November 1, 2019.
Keywords: regional innovation, open social platform, data-driven society

1. Do innovations occur in Japan?
Japan is ranked sixth in the World Economic
Forum’s global competitiveness ranking. However,from indicators of the country’s suitability for innovative business, Japan is ranked 14th, a low standing
among developed countries. The world’s grossdomestic product (GDP) has grown over the last 30
years. As part of this trend, Japan’s GDP has grown
120%. However, the GDP of European Union countries have at least doubled, while the GDP of theUnited States has grown 330% and China’s hasgrown more than tenfold. Considered in this light,
Japan has become a country that really does not grow.
Can the people of a country without economic
growth be happy? Japan is ranked 58th in the World
Happiness Report. This suggests that the Japanese,
faced with social issues such as a low birthrate, aging
society and pension crisis, have a hard time feelinghappiness that comes from having children withpeace of mind and leaving a legacy to the next generation. Many of the top spots in the happiness ranking are occupied by small countries such as those innorthern Europe. However, these countries also enjoy
growing per-capita GDP. Japan, on the other hand,does not have a view that tomorrow will be better than
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

today or a future 20 years down the road will be better
than tomorrow.
2. Have innovations by GAFA (Google, Amazon,
Facebook, and Apple) brought happiness?
What innovations should occur in Japan? Revenuesof GAFA, which have created innovations that dominate the world, have certainly been increasing sharply. However, there is a book, titled Hired: Six Months
Undercover in Low-Wage Britain about the experience of working in an Amazon.com warehouse and as
an Uber driver. I went to Seattle earlier this year andobserved an Amazon warehouse. I saw how artificial
intelligence (AI) efficiently controlled workers andsystems. Amazon workers have heavy workloads at
low wages, for which Amazon is being criticized by
the mass media. Labor’s share of the economy in the
United States has been trending downward. The theory is that large companies, such as GAFA, have kept
profits to themselves instead of returning them totheir workers.
3. Open social platform
GAFA adopt a business model based on the35

Feature Articles

Analysis,
prediction

Real-timeprocessing

Monitoring,
notification

AI

While humans can spend more time withcreative tasks, AI will take over harder tasks.

Fig. 1. Shift to AI that supports humans.

monopolization of collected data. In this model,
world data are sucked up using a variety of methods
such as social networking services and advertisingmodels, and the data are used to improve the company’s products and content. Many people worldwide
are now raising their voices in concern over this business model.
At NTT, our business model does not monopolize
data. Instead, we create data lakes that gather datafrom all sorts of places and willingly share them withthe rest of society. Together with all of you, we wantto create a society that can become more prosperous.
If we create a model with which data are used by allof society, then Japan will once again draw the attention of the rest of the world.
4. Leverage AI so that people can do morecreative work
How to promote a set of ethics of AI and people
co-existing, instead of people being used by AI, isbeing debated (Fig. 1). If we can create AI that plays
a supporting role in helping people when they are introuble instead of AI being used in place of people,
then I believe we can achieve social innovations thatcommand the attention of the world.
4.1 J apan’s renaissance will be difficult without
regional revitalization
I will now explain NTT EAST’s efforts to reinvigorate Japan based on our partnerships with our customers. Japan’s working population is continuing to
decline; therefore, we must consider how to move
Japan forward.
Japan’s per-capita productivity is ranked 20th
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Vol. 18 No. 4 Apr. 2020

among Organization for Economic Cooperation andDevelopment (OECD) countries, an extremely low
position. However, if we look at just the productivityof Tokyo, we see that its productivity exceeds that ofsixth-ranked United States. This fact shows that without thinking about how to revitalize Japan’s regions,
it will be difficult for Japan to grow again.
4.2 I nnovation by improving the productivity ofsmall and medium-sized enterprises (SMEs)
Another challenge is the disparity between SMEs
and large companies. The productivity of large companies is high. In the past ten-odd years, however, theproductivity of SMEs has not grown. SMEs make up
99.7% of all companies in Japan. We must think
about how to create digital transformations in SMEs
and improve their productivity.
More than half of all owners of Japanese SMEs areover the age of 70. Increasingly, they are shuttering
their companies, not because of stalled business leading to bankruptcy but because there are no successors
to take over the businesses, despite them still being
profitable.
Another challenge facing regional SMEs is thatthey have no information technology specialists who
can use technologies to reduce workload and improve
productivity. If AI can handle the heavy labor of a job,many farmers and manufacturers may be able to continue their business. However, it is currently difficult
to extend a helping hand to these SMEs.

36

Feature Articles

Number of people (million)

60
50

Secondary industries

80

Primary industries

70

Food self-sufficiency
rate

60
50

40

40
30

30
High economic
growth period

20

20

10
0

10
Primary industries
1951

1960

Food self-sufficiency rate (%)

Tertiary industries

70

0
1970

1980

1990

2000

2010

2018

Source: Ministry of Internal Affairs and Communications, “Labor Force Survey”

Growth in the primary industries is key factor.

Fig. 2. Industrial structure balance and food self-sufficiency rate.

5. Creating regional employment by revitalizing
primary industries
I would like to reiterate the general social trend taking place throughout Japan. Japan’s population is
falling, and in 2065, there needs to be 1.3 persons ofworking age to support one elderly individual. We
must work to grow Japan and create a path to double
its per-capita income.
Looking at the number of workers in each sector of
the economy (Fig. 2), we see that young people areheavily employed in the service sector, whose customers are mainly based in Japan. The primary industry sector, i.e., industries concerned with providing
the raw materials for manufacturing such as agriculture, fishery, and forestry, is shrinking yearly. While
Japan’s regions depend heavily on such industries,
the country has not focused on how to strengthen
them, particularly regarding agricultural production,
livestock husbandry, and fisheries. How to reinvigorate these industries will be the key to regional revitalization.
Over the past 50 years, the number of agricultural
workers has fallen 80%. What’s more, 80% of theseworkers are over the age of 60, and abandoned farmlands are increasing rapidly. If we can effectively use
land and improve productivity, then not only the
manufacturing industry but also primary industries
can become export industries and serve as anotherpillar of Japan’s economy. We therefore seek to revitalize Japan’s regions through improving SMEs’
productivity and reinvigorating primary industries.
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Vol. 18 No. 4 Apr. 2020

5.1 Regional circular symbiotic communities forJapan
At NTT EAST, we aim to support the creation ofregion-based circular symbiotic communities toimprove SMEs’ productivity and reinvigorate primary industries. For example, we can collect and convert
manure from cows and wood chips from the timberindustry into locally produced, locally consumed
energy such as heat produced by biomass plants. For
example, using this energy, caviar can be cultivatedby aquaculturists, and the remains of the fish can becomposted. To promote such communities, we seek
to engage in leveraging digital technologies forJapan’s regions.
5.2 Example of effort in the agricultural field
Based on the awareness of the issues describedabove, we at NTT EAST began to focus on agriculture. Agriculture faces a variety of challenges, such asa lack of workers, damage by wildlife, and natural
disasters. However, there are countries that have succeeded with agricultural innovations. Even though
the Netherlands has just one-tenth the surface area ofJapan and its population is only 16 million people, its
agricultural sector has expanded dramatically afterWorld War II. The country is now the second-largest
agricultural exporter in the world. The Dutch havecreated next-generation greenhouse horticulture with
5 times the crop yield per area than that of Japan. The
Netherlands have established a region called FoodValley, like Silicon Valley for technology in the
United States (Fig. 3). With Wageningen University,37

Feature Articles

Public agriculturalexperiment stations

Financial institutions
Start-up companies

Distribution facilities

Farmers
Collective impact inFood Valley(e.g. Wageningen)
Agricultural consultants
Manufacturers

Research institutions

Universities

Promoting innovations in food through research and businesscollaborations among industry, government, and academia

Fig. 3. To establish next-generation protected horticulture (Netherlands).

the world’s most advanced university in the agricultural field, at the center, Food Valley is creating asystem that connects stakeholders from a variety oforganizations, such as public agencies, research institutes, manufacturers, and farmers. This region isformed by holistically researching and solving problems from a variety of angles. Questions include how
to create high-quality seeds with biotechnology, how
to improve the crop yield and production efficiency,
and how to optimally distribute crop products to markets.
6. Collective impact
An idea that has gained attention is collective
impact, which means building up an entire industry
by bringing together the strengths of companies, government agencies, and research institutes, and sharing
goals, as done in the Netherland’s Food Valley,
because the efforts of individual companies alone
have their limits. In short, it is a philosophy that
believes that combining powers results in transformations that impact society. We see countries such as the
Netherlands that have succeeded with collective
impact. We believe that the same can happen in
Japan.

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Vol. 18 No. 4 Apr. 2020

7. Two digital transformation approaches foradvancing agriculture
As I have explained above, NTT EAST has begun
efforts to revitalize SMEs and primary industries
through digital technologies. I would like to introduce two real-world examples of efforts that we havebeen engaged in regarding agriculture (Fig. 4). There
are two approaches to digital transformation, Mode I
and Mode II. Mode I is a forward-casting approachbased on the current method of agricultural practices.
With this approach, productivity improves throughdigital technologies. Mode II, on the other hand, is abackcasting approach. It defines a completely new
future condition as the starting point and considers
what should be done to achieve that future. An example is completely changing the current agricultural
methods by, for example, optimizing the Netherland’s next-generation greenhouse horticulture forJapan. By adopting both Mode I and Mode II, regional revitalization can blossom, attracting industries
and employing young people.
7.1 Mode I: Yamanashi model
I would like to introduce our effort in Yamanashi as
an example of the Mode I approach. Shine Muscat
grape farmers in Yamanashi actively partner with the
JA (Japan Agricultural) cooperative Yamanashi
Fruits. There is a farming couple who are both over38

Feature Articles

Mode II
Mode II is neededto achieve all new
5K’s

Back casting“Kasegeru”(“can earna living”)

Creation ofadvanced agriculture“Kirei”(“clean”)
Realization of
the new 5Ks“Keisagyo”(“light work”)
Mode I
Forward casting
Improvement of
current methods“Kakkoii”(“cool”)
5K“Kyuka ga toreru”(“can take avacation”)“Kitanai”(“dirty”)“Kitsui”(“tough”)“Kyuka ga nai”(“no vacation”)“Kasegenai”(“cannot earn “Kakkowarui”(“not cool”)
a living”)

Fig. 4. Two approaches for advancing agriculture.

the age of 70 operating ten plastic greenhouses.
Because Yamanashi is extremely hot in the summer,
air conditioning must be used when the temperature
exceeds 35ºC or all Shine Muscat grapes will become
damaged. Therefore, the wife must visit the ten
greenhouses every day to manage the air conditioning, a really laborious task. If we can just lighten thistask, farming can continue for generations.
To assist such farmers, we are carrying out remotemonitoring and data gathering by attaching Internetof Things (IoT) devices externally to existing facilities. With JA Yamanashi Fruits as the center, we aregathering cultivation data from many farmers andparticipating in ventures with the University of
Yamanashi. By using temperature, carbon dioxide,
and cultivation data to improve the quality of the
Shine Muscat varietal and determine the timing of
shipments, we have been able to develop a data-driven approach for improving crop yield and providing
guidance in agricultural management (Fig. 5).
7.2 M
 ode II: Next-generation greenhouse horticulture model
As an example of the Mode II approach, we established a company called NTT AgriTechnology on
July 1, 2019 to be fully engaged in agriculture. I now
introduce NTT AgriTechnology Senior Vice President Daiki Endo’s to give his thoughts and the company’s specific efforts.
[Daiki Endo, Senior Vice President, NTT AgriTechnology]
My parents were rice farmers. Looking at the lack
NTT Technical Review

Vol. 18 No. 4 Apr. 2020of workers due to the aging of society, including myrelatives, I wondered if I could be involved in farmmanagement in the future. I wanted to study onsite
what leads to profitable and leading-edge agriculture,
so I wanted to be a trainee at Salad Bowl.
Salad Bowl is an agricultural production corporation at the leading edge of agriculture and operates
several large Dutch-style horticultural facilities inJapan. The structure and facilities of the greenhouses
have unique characteristics and are well-lighted. The
company is practicing a variety of labor-efficient
Dutch methods and achieving originality by combining Dutch expertise and Japanese techniques.
In the Netherlands, agricultural technology is centered on supplementing many insufficient components such as sunlight and carbon dioxide. However,in highly humid Japan, instead of adding (supplementing), components must be removed. Salad Bowl
has been successful in applying expertise in multiple
domains in a Japanese manner to this difficult problem as it operates several cultivated fields.
What can NTT EAST offer to this enterprise? One
key is improving productivity and reducing energy
costs. Liquid petroleum gas and electricity are used tocontrol the environment. I believe NTT EAST’s IoTtechnology and information and communication
technology (ICT) have a role in visualizing andimproving the efficiency of these resources.
In fact, NTT EAST is conducting field tests at Salad
Bowl’s cultivated fields. We are estimating the crop
yield for the next day after taking images of a field. If
the amount of harvest is known, then the number of39

Feature Articles

Yamanashi City

Internet

Internet
Cloud
service

Synaptech(Collaboration with Yamanashi
Univ. and others)
Collection ofenvironmental
information

Increase of
temperatureinside thegreenhouse

Wi-Fi
access point
Filming offarm situation

IoT sensor

IoT camera

IoT-compatible sensor devices for agriculture

Real-time
monitoring

Visualizationof data

Environmental
information

ImagesTablets,
smartphones, etc.

NTT EAST

JA Yamanashi Fruits

Occurrenceof abnormal
eventsUse in providing
farming guidance

FarmerSupport for farming and labor-saving for farmers in collaboration
with JA and local government

Fig. 5. Collaboration with Yamanashi City and JA Yamanashi Fruits.

workers can be assigned accordingly. By delivering
information on tomatoes to the market in advance, forexample, the appropriate amount of the produce canbe sold without excess inventory. IoT and ICT makethis possible.
We have received requests not only from Salad
Bowl but also various regions and municipalities.
Therefore, NTT EAST established NTT AgriTechnology to engage in agriculture and provide fieldtested solutions. By forming an even stronger partnership with Salad Bowl than before, we are contributing
to the adoption of large-scale greenhouse horticulture
nationwide and promoting community development
through building greenhouses.
8. Aiming for regional revitalization andcommunity development through“Agriculture × ICT”
Summarizing Mode I and Mode II, we at NTT
EAST, who are not experts in agriculture, want toform lasting partnerships with farmers who wish toleverage digital technologies to bring about mutual
benefits. Looking to the Netherland’s success in agriculture, we at NTT EAST want to build up a region’s
industry together with universities and consultants inthat region. In line with this goal, we wish to workwith regional stakeholders to support a circular sociNTT Technical Review

Vol. 18 No. 4 Apr. 2020

ety that carries out local production of energy for
local consumption.
9. Networks for supporting regionalsocial innovations
Because we are a network company, we must create
networks to support regional revitalization. We wish
to build them together with NTT R&D and manufacturers. Leveraging data by data scientists is the current focus. However, it is difficult to collect data
pre-formatted at a level where AI analysis is possible.
We want to create a framework for data lakes wherereliable data are gathered. For this goal, our mission
is to collect data from every conceivable source, suchas from 40 billion IoT devices and drones and satellites, and create edges for computing in regions sothese data can be openly used for social innovations.
Data obtained from sensor devices, drones, andsatellites have different characteristics concerning
data-acquisition range, resolution, and freshness. A
perspective on how to gather data by combining thesecharacteristics is critical. Previously, satellites haveused optical sensors to capture images; thus, imagesof ground surfaces could not be obtained in bad
weather. However, ground-surface information can
now be obtained regardless of the weather by using
microwave radar. By launching several hundred
40

Feature Articles

Application
layer

REIWA Project: Regional Edge with Interconnected Wide-Area Network
Cloud

AI

Data analysis
Real-time processing

Infrastructure layer

Collaborate with various partners and solve
social problems by leveraging data

Cloud

Alive monitoring

Connect
centerNetwork

AI

Autonomous control and optimization by AI

Data lake

0010100
11011

Closed network

Mechanism for efficiently storing large amountsof dataStandardization, reliability, encryption, etc. of data
Robust and large-capacity networks that securely
deliver data
Preliminary processing of image data on the edge

IoT gateway
Terminals

Mechanism for blocking threats at gateways
Terminal management, condition monitoring,connection management, etc.
Easily connect various devices

Solve the social issues faced by the regions

Fig. 6. Social infrastructures that guarantee the reliability of data.

low-earth orbit satellites, whose cost has fallen sharply, and obtaining images with microwave radar in
regular intervals, information can be obtained at very
short cycles. NTT EAST became a member of thexData Alliance on October 24, 2019 and announced
that we are fully participating in space ventures.
With regard to local fifth-generation mobile communications (5G), we cannot simply deploy local 5G.
To solve a region’s difficulties, we must build networks that use a best mix of all network types, including optical fibers, Wi-Fi, low power wide area, andlocal 5G.

works that draw out wisdom from a variety of users
for social innovations such as AI.
Specifically, through IoT gateways, we carry out
alive monitoring of devices and use inference techniques to remove data determined suspicious whenabnormal behavior is observed during monitoring.
We wish to create a regional edge network with Innovative Optical and Wireless Network (IOWN) as aset. We want to engage in this effort with the help ofresearchers, developers, and manufacturers.

10. Toward developing secure IoT

Finally, NTT EAST is visiting municipalities,
farmers, and universities to build partnerships to promote digital-technology-based regional revitalization
and a circular society (Fig. 7). Thanks to our partners,
this effort has been well-received. Many municipalities and JA said that until now, no large companies
have worked with them in this field, so they are eager
to work with us. There have been many companies
that immediately disappear after reaping the benefitsof a partnership. Therefore, they said they wanted us
to put down roots in their communities. I want toanswer with confidence that we are working on
regional revitalization and industrial developmentwith the support of everyone in the community. To
strengthen Japan, it is necessary to solve challenges
faced by regions and SMEs. We appreciate support

There are security issues with IoT technology(Fig. 6). Many IoT devices have low-spec processors
and memory and are not updated, leaving them withmany security holes. Their data handling is thus notreliable, and they cannot be used for mission-critical
purposes such as medicine and automated driving
where lives are at stake. Therefore, our mission is tomake IoT technology trustworthy for handling data.
It is critical to have an environment where data
entrances and exits are robustly protected, even whena variety of devices are connected, clean up data
while processing appropriately at edges, and enable
the data to be used by data scientists in the upper
layer. We wish to build next-generation edge netNTT Technical Review

Vol. 18 No. 4 Apr. 2020

11. To bring about regional social innovations

41

Feature Articles

Local governments

Farmer

ICT industry
Distribution
industry
non-governmentalorganization

Educational
institutions

Collective impact

Financeindustry

Consultants
Livestockfarmers
Let’s focus on our common goal to bring abouta prosperous future and create regional innovations!

Fig. 7. To generate regional social innovations.

from research institutes and related companies concerning this endeavor.

Naoki Shibutani

Senior Executive Vice President, NTT EAST.
He received a B.E. from Kyoto University in 1985. He joined Nippon Telegraphand Telephone Public Corporation (now NTT) the same year. In June 2014, hebecame senior vice president of NTT EAST and executive manager of Plant Planning Department and 2020 Preparation Department. In July 2017, he also became
director of Tokyo Olympic & Paralympic Promotion Office. In June 2018, he also
became the representative director of NTT EAST, senior executive manager of New
Business Development Headquarters of NTT EAST, and president of NTT VIETNAM. In July 2019, he also became senior executive manager of Digital Transformation Headquarters of NTT EAST.

NTT Technical Review

Vol. 18 No. 4 Apr. 202042

Feature Articles: Keynote Speeches/Workshop
Lectures at Tsukuba Forum 2019Technical Trends in Infrastructure
Maintenance Management
Minoru Tanaka
Abstract

In the Civil System Project of NTT Access Network Service Systems
Laboratories, we are working to achieve permanent infrastructure by implementing smart operation of facilities. We introduce new maintenance management for conduits, manholes, and tunnels. This article is based on alecture from a workshop held on November 1 at Tsukuba Forum 2019.
Keywords: degradation prediction technology, high-accuracy location
information acquisition technology, 3D model management

1. Direction of maintenance management
NTT has constructed many infrastructure facilities,
including underground conduits, manholes, and tunnels. Most of these facilities are over 30 years old andhalf are more than 50 years old. We have been using
the plan-do-check-action cycle of inspection, planning, and repair to extend the life of these facilities.
The cycle involves regular inspections that reveal
abnormalities, detailed inspections, selection of optimal repair methods according to the inspection
results, and repair work. This approach, known as
preventive maintenance and post-preservation, istaken only from the post-construction perspective.
Repairs are made only after facilities have deteriorated, so it is a rather defensive approach to maintenance management.
We ask the question, “What parts deteriorate, when
do they deteriorate, and how do they deteriorate?”
Knowing the condition of each facility can dramatically change maintenance work. This is a shift
towards offensive maintenance. What is most important is technology for predicting deterioration. Deterioration can be accurately predicted by identifying
which part is deteriorating and the mechanism bywhich it is deteriorating, and then estimating the deterioration period.
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

Accurately predicting deterioration makes it possible to manage the state of each facility and perform
detailed maintenance tasks such as planned repairs.
Although we can expect deterioration of facilities
built in the era of mass construction, such detailed
planning of repairs can facilitate a leveling effect on
construction. That is to say, enabling fine control on
the management side will make preservation work
greatly different from the conventional approach of
waiting until facilities have already deteriorated. Our
objective is to change how maintenance work is done.
Our approach is described in detail below.
1.1 M aintenance based on prediction and monitoring
It was not previously possible to predict where,
how, and when a structure would deteriorate. The
basic approach has been to conduct periodic inspections, decide on repairs according to how much thefacility’s functionality has decreased, and select themost appropriate repair method for the facility if
repair is needed. After repair, however, the cycle ofinspection and repair continues, so it has not beenpossible to determine the deterioration mechanism or
supplement parts for which the deterioration-reduction mechanism cannot be identified.
We are currently conducting research and43

Feature Articles

Strength

Inspection

Present

Preventive maintenanceAll facilities

RepairRepairstandard

Plan

Continuous periodic inspection (every 5 to 10 years)

Transformation of maintenance

Near future

Deterioration
prediction/
Monitoring

Prolonging life through repair

Increase inspection
efficiency

Predictive maintenance
Strength

Strength

Standard facilities

Monitoring-based maintenance
Atypical facilities(manholes, manhole
covers, tunnels)

RepairRepairstandard(considering
LCC)

Years

RepairDeterioration prediction
Repairstandard(considering
LCC)
Years

(bridges, tunnels)
Monitoring

RepairYears

New construction method
Development of new materials

FutureMaintenance-free world

LCC: life cycle cost

Fig. 1. Direction of maintenance management.

development (R&D) on clarifying deterioration
mechanisms for infrastructure facilities and havebeen successful regarding various types of facilities.
If mechanisms can be identified, periodic inspections
would not be needed to determine what parts to repair
and when to repair them. Instead, it is possible topredict deterioration and carry out predictive maintenance. We will be applying this approach to standard
facilities such as manholes and manhole covers.
However, predicting deterioration in nonstandard
facilities, such as specialized bridges and bridgeattached conduits, is difficult, so monitoring-based
maintenance will be carried out. Concerning largescale tunnels, we will move forward with a hybrid
system that combines predictive maintenance andmonitoring maintenance (Fig. 1).
1.2 S
 hifting maintenance management fromdefense to offense
We have thus far taken measures so that facilities
older than 50 years can be used for 100 years or so.
We also intend to evolve maintenance managementfrom the conventional defensive approach to an
offensive approach to further extend service life sothat facilities can be used without concern for 150 ormore years (Fig. 2). To achieve this goal, we must
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

take a new technical perspective in developing management methods to replace the conventional inspectand-repair approach from a post-construction perspective. To achieve an ultimate maintenance-freeworld, we are moving forward with new innovative
R&D regarding construction and repair methods
using new materials and inspection methods and creating new databases.
As described above, preventive maintenance basedon deterioration prediction and monitoring-based
maintenance serve as core technologies and are supported by databases. Because there is a huge amountof data and the role of the database as the foundation
for advanced management through the use of various
applications, there is a need to evolve from twodimensional (2D) management on paper towards
management in three or four dimensions with a timeaxis. Database evolution will result in changes inrelated tasks. For example, 3D management throughvisualization of underground spaces would make itpossible to understand the situation of undergroundfacilities as if a person were on-site and touchingthem. Previously, it was necessary to look at drawings
on paper and imagine the required assembly, but now
staff can easily share the same underground space without having such special skills. We call this digital
44

Feature Articles

Past

50 years fromconstruction

PSTN

FTTH

Present

FutureFurther 100 years

NGN

IOWN

???

???

Support next-generation network services

Construction era
Offensive maintenance (persistent evolution)
Inspection and repair froma post-construction perspective

Innovation!

Full use of AI/AR/VR,
skill-less,automation

Develop management method froma new perspective
Predictive maintenance
Detect deterioration using AI
Monitoring-based
monitoring
Maintenance-freemaintenance

MaintenancePreventive and expost maintenanceEngineering

Design, calculation

Automatic design and calculation
Automatic construction

Observing

Local response

Automatic detection

Disaster measures

Damaged-area identification

Accurate damage prediction
Damaged equipment identification Visualization

Facility database

2D management

Location-informationacquisition

Data acquisition and efficiency
improvement through inspection

AI: artificial intelligence
AR: augmented reality
D: dimensional
DB: database
FTTH: fiber to the home

Towards a world ofsmart operations

3D management

4D management

Data acquisition and inspection
methods from a new perspective
Longer life by developing new materials

IOWN: Innovative Optical and Wireless Network
NGN: Next Generation Network
PSTN: public switched telephone network
VR: virtual reality

Fig. 2. Transform maintenance.

transformation (DX).
We are aiming to reduce manual work by combing
artificial intelligence (AI), augmented reality (AR),and virtual reality (VR) with advanced database management. For example, the inspection of facility
structures requires automation and autonomous
operation with robots, etc., so we are pursuing R&D
on automated inspection technology using unmanned
aerial vehicles, etc.
Our R&D also includes application of AI to automatically detect deterioration using digital images
taken during inspections as well as damage prediction for infrastructure facilities using a highly accurate 3D database. In engineering, AI-assisted design
and assessment and automated machine construction
at the worksite are also possible. AR can be used toincrease efficiency in on-site inspections, and futureadvances will enable elimination of on-site inspections. Such 3D databases require highly accurate
coordinates, so R&D on highly precise acquisition oflocation data from a global navigation satellite system (GNSS) is also in progress.
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

2. R&D on infrastructure
2.1 I nfrastructure tasks (for conduits and manholes)
Correct and accurate location information is needed
to increase the efficiency of conduit and manhole
work, so technology for acquiring highly accurate
absolute coordinates is important. Specifically, using
a single-frequency GNSS to measure the location of
newly constructed conduits and ground-penetratingradar for locating existing conduits are current R&D
topics.
Highly accurate acquisition of absolute coordinates
would enable sharing of precise facility location
information with other lifeline providers in the implementation of the “i-Construction*” measures of the
Ministry of Land, Infrastructure, Transport, and Tourism. Doing so would make it possible to automate the*i-Construction: A measure initiated by the Ministry of Land, Infrastructure, Transport, and Tourism to improve productivity of
the construction industry using information and communication
technology.

45

Feature Articles

High-precisionabsolute coordinate
measurement

Drawing-management system(NTT)i-Construction(MLIT)

Addition of 3D display
and design functions

Smart infrastructure platform (tentative)
ManholeCoordinate
sharingNTT

Culvert

3D display

Electric power
Water
Gas

©NTT GEOSPACEDX of NTT

Drawingmanagement
Completion processing
operation: Decrease
Cooperation with roadmanager: Decrease

Design &Automatedcalculation
construction
Operation: Decrease

Editable

DX ofoperation

Coordinate
sharing

Reception
External work observation
reception: Zero
Obstacles removal work
reception: DecreaseOn-siteExternal work observation
reception: Zero
Buried object exploration,
prospecting: Zero

Drawing-management system(each company)
Road

Water

Gas

DB

Electric
power

MLIT: Ministry of Land, Infrastructure, Transport and Tourism

Fig. 3. Effect of acquiring high-precision absolute coordinates.

nAutomatically determine
deterioration degree using images
Captured
imagespgtio
Deteriora
degree III

Commercial
technologies

Automatically determining the degree of facility deterioration from captured images

Determine deterioration
Facilityy extraction Deterioration detection
For individual degree for each facility
facilities

Applicable to each imageacquisition method
By drone

By special equipment

By engineer
Automatic deterioration-detection technologies (Step 1)
Technologies for automatically determining deterioration degree (Step 2)

Deterioration degree III
Deterioration degree II
Deterioration degree I

Fig. 4. Determining degree of deterioration with AI.

construction-completion processing, exclusive-use
management, and design and assessment work. It
would also lead to more efficient outside inspection
work and acceptance of transfer work. In other words,
it will lead to the promotion of DX in other companies as well (Fig. 3).
We have been working on using AI for detecting
deterioration to improve the efficiency of bridge
inspection, and this work is presented in this article asa case study (Fig. 4). Currently, various types of
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

inspection images are acquired by drones, special
equipment, or cameras operated by workers, etc.
Skilled individuals who determine the degree of deterioration examine images. Our objective is to automate this process so that individuals who do not havespecialized skills can do it.
The first step in the process is to distinguish NTT
facilities from those of other companies in theobtained images. Then, the NTT facilities are examined for corrosion, and the parts where corrosion
46

Feature Articles

Fig. 5. Visualization image with 3D model.

exists are identified. It is now possible to detect corrosion with a high probability of success, and we arecontinuing this work with the goal of automating thedetermination of the degree of deterioration. Therefore, digital images can be used to determine what
facilities are deteriorating, thus increasing efficiency.
2.2 Infrastructure tasks (for tunnels)
We are conducting R&D on using 3D models inmanaging tunnels. This technique visualizes the situation of underground spaces in a manner similar tothe street-view function of satellite map services,making it possible to also reference the history of theinspection location (Fig. 5). Workers can view thefacilities in 3D with a sense of themselves being in
the tunnel. Also, a skeleton view of the tunnel makes
it possible to know the placement of the reinforcement bars. For shield tunnels, it is possible to view thestate of the primary lining, and any inspection point
can be checked in cross-section. Although research isstill in progress, it is possible to view from any angle,
direction, or cross-section at any time. Implementing
this technique will increase work efficiency.
To increase the efficiency of cable-tunnel management, we are currently focusing on three points: 1)
full automation of monitoring and inspection using
3D models, 2) central management of facility information using 3D models, and 3) remote support for
on-site personnel. Tunnels throughout the country
will be monitored at a central monitoring center, and
3D information will be used for viewing facility
information (Fig. 6). Also, data on environmental
changes, such as temperature and oxygen concentration, in tunnels can be acquired from sensors in realtime. Cameras can be used for central monitoring ofsites where work may be dangerous and the status offacilities can be checked during natural disasters. The
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

ability to quickly dispatch monitoring capabilities todisaster sites with robots and drones is also desirable.
Unified management of facility information with
3D models is another method of increasing efficiency. Facility-location data are managed as absolutecoordinates, making it possible to visualize the situation in cable tunnels in a manner similar to the streetview function of mapping programs, obtain historical
data on inspection points and the placement of reinforcement bars, and browse shield segment arrangements. Real-time monitoring with cameras is also
possible.
Remote support for workers is important because
the interior of tunnels is very complicated, especiallyin Tokyo. Workers who go into tunnels to inspect orrepair must be kept informed of environmental conditions, such as temperature, humidity, and oxygen
concentration, via real-time communication using
tablet devices, etc. Workers can also access the resultsof past inspections and repair history and determine
their current position and the route to the destinationfrom a navigation display on the screen. Emergency
evacuation guidance can also be given, the escapedirection can be displayed, and communication withthe monitoring center is possible, providing support
for workers in real time.
3. Future development
Our objective is to make daily progress in increasing the efficiency of the maintenance management of
infrastructure facilities. We also expect that the transformation of databases from 2D to 3D or even 4D will
accelerate the DX of business. To continue providing
a safe and secure infrastructure, the Civil System
Project will promote R&D that creates value throughadvanced technology in fields such as materials,
47

Feature Articles

Remote monitoring
Centralized monitoring via
monitoring base server

Hazardous locations
monitoringOn-site confirmation at disasters

Checking the premises when an
alarm is triggered

Fig. 6. Fully automated monitoring and inspection with 3D model.

information, telecommunications, and robotics, andfuse expertise in other fields. We will also contributeto the DX beyond NTT infrastructure facilities inbusinesses throughout the social infrastructure.

Minoru Tanaka

Executive Research Engineer, Civil System Project, NTT Access Network Service
Systems Laboratories.
He received a B.E. and M.E. in civil engineering from Kyoto University in 1990
and 1992. He joined NTT in 1992 and has been involved in a wide range of tasks,
including planning, maintenance, and R&D related to telecommunication infrastructures.

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

48

Feature Articles: Keynote Speeches/Workshop
Lectures at Tsukuba Forum 2019

Wireless Systems Technologies for
Present and Future Services
Takeshi Onizawa
Abstract

The NTT Group provides a wide variety of services to its customers, andwireless technologies have an important role in supporting these services.
Various methods of using wireless services are provided according to thecharacteristics of the frequency bands. This article introduces research anddevelopment directions in wireless technologies for supporting wirelessservices in the very high frequency (VHF), ultra-high frequency (UHF),
microwave, and millimeter-wave bands. We also discuss the current stateand future expansion of satellite communications and wireless local area
networks (LANs).
Keywords: VHF/UHF/microwave/millimeter-wave bands, satellite communications, wireless LAN

1. Introduction
Needs and usage scenarios for wireless communication systems as a communications infrastructure
continue to expand. In particular, traffic generated bymobile communications is increasing due to thewidespread use of smartphones and tablet terminals.
The development of wireless services and theirspread is shown in Fig. 1. Past wireless services
focused on telephone services such as subscriber systems and relay systems. This was followed by wireless services being more integrated into daily life as
diverse wireless systems were developed anddeployed independently such as cellular systems,
satellite systems, and wireless local area networks(LANs). In the near future, we can expect the linking
and fusing of these wireless systems. Current wireless systems will be enhanced by using a wide rangeof frequencies from low-frequency bands to highfrequency bands, i.e., from very high frequency(VHF) bands to millimeter-wave bands, by using new
systems applying low-earth-orbit (LEO) satellite andradio-over-fiber (RoF) technologies, and by fusing
these current wireless systems with high-density
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

wireless LANs. To meet high expectations for thesewireless services, NTT Access Network Service Systems Laboratories is researching and developing
methods of exploiting the advantages of these systems. These wireless systems enable a highly convenient world in which all manner of things are connected through wireless technologies.
At the same time, our research and development(R&D) efforts have been focused on anti-disastermeasures since the Great East Japan Earthquake of
2011. These include studies of wireless systems for
dealing with disasters by quickly restoring and constructing the communications infrastructure after awide-area disaster, which could greatly impact customers. We have been upgrading and enhancing various types of wireless systems for conventional antidisaster systems and for the revised spurious-emissions standard.
To achieve even higher transmission speeds in theface of expanding usage scenarios for wireless communication systems, recent studies considered technologies for using even higher frequencies in the
millimeter-wave band. One of these studies focusedon the rapid traffic increase in urban areas. This study
49

Feature Articles

Stationary
satellite
Anti-disastermeasures
LEO satellite

Subscriber system

Low-frequency
band

Cellular
Relay system

Wireless LAN

Wireless entrance
RoF,
high-frequency
band

Focused onphone services
Stadium
Development of diverse wireless services

Development of fused services
LAN: local area network
LEO: low-earth-orbit
RoF: radio over fiber

Fig. 1. Development of wireless services and their spread.

aimed at applying millimeter-waves to wirelessentrance systems connected to remote base stations
for small cells, large numbers of which will likely tobe necessary in the future. Connecting wirelessentrance systems to small-cell remote base stations inplace of optical fibers will enable flexible base-station-deployment design. We are studying high-frequency-band analog RoF technology for softwarizing
wireless transmit/receive functions for wireless central base stations. This study is proceeding in the
direction of minimizing power consumption of
remote base stations and inheriting the advantages ofcellular stations such as compact and low-power
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

characteristics.
Attention has also been on satellite communication
systems in the wake of the Great East Japan Earthquake because of their inherent features such as widearea and immediate communications. However, conventional satellite communication systems at thattime suffered from old equipment and obsolete operational maintenance procedures. This led to the development of high-efficiency signal-processing equipment for disaster control and earth stations on remoteislands where the laying of optical fiber is difficult.
The grouping of this equipment into systems has also
progressed. There have also been recent studies on
50

Feature Articles

140 cmConventional antenna

Compact
antenna
70 cm

Urban compact
antenna

31 cm

Fig. 2. UHF anti-disaster measures and downsized antenna.

applying LEO satellites to satellite communication
systems to explore their use in future communications.
Wireless LANs are also making great progressbeyond their conventional role of being just a meansof communications in unlicensed bands. It is becoming a system that can significantly expand the reachof users. Therefore, various rich services, i.e., thosethat have high-efficiency and high-density performances, are being provided through the current andfurther development of wireless LANs.
In the following sections, we introduce our current
R&D directions in these wireless technologies.
2. VHF/UHF /microwave-band wireless systems
We first introduce our R&D activities using theVHF, ultra-high frequency (UHF), and microwave
bands. We describe anti-disaster systems using the
UHF band for wide-area disasters that have attracted
interest following the Great East Japan Earthquake.
We used these systems including a microwave bandsystem for the torrential rain that fell over westernJapan in July 2018.
The NTT Group considers the construction of a
network robust against disasters and the means ofproviding early restoration after a disaster as critical
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

issues. Our wireless communication systems for antidisaster measures are advantageous in terms of equipment mobility and early restoration. However, theproblems of aging facilities and a lack of personnel
with specialized skills are only becoming worse.
Thus, the need has arisen for upgrading facilities andimproving their operability and maintainability.
Based on this background, we developed an antidisaster wireless communication system with a rangeof several tens of kilometers using the UHF band.
From lessons learned from the Great East Japan
Earthquake, this system was also designed to provide
a point to multi-point communication configuration,
which can consist of multiple wireless terminal stations and a single wireless base station. It was also
developed under a variety of requirements such as theprovision of Internet-connection functions in addition to special public telephones and the capability todeal with wide-area disasters brought on by mammoth earthquakes and tsunamis. We improved themobility and operability/maintainability of equipment such as through compact and lightweight
designs. We developed in parallel with this system acompact antenna using a phased array method with a
total length one-half that of conventional antennas aswell as an even smaller antenna for urban use (Fig. 2).
Examples of UHF and microwave band systems
51

Feature Articles

Soja City
OkayamaPrefecture
Kurashiki
City

Ehime
Prefecture

Location

Wireless system

NTT West Soja Bldg.

UHF anti-disastermeasuresSono elementary
schoolUHF anti-disastermeasuresOkada elementary
schoolUHF anti-disastermeasures

Mabi Comprehensive
Park Gymnasium

Anti-disastersatellite

Location

Wireless system

NTT West Ozu Bldg.
Ozu
City

Kannan wireless relay
stationMicrowaveband relay
systemHigashi-ku Assembly Hallnear NTT Moriyama Bldg.

Fig. 3. Examples of wireless systems used during torrential rain in western Japan.

used in response to the torrential rains in westernJapan are shown in Fig. 3. Specifically, UHF antidisaster systems were used in Okayama Prefecture,
and a microwave-band relay system was used in
Ehime Prefecture.
From the viewpoint of applying the VHF band toregions where wired equipment is difficult to install,such as national parks and super-rural areas outsidemobile-phone coverage, the effects of long-delay
waves must be clarified considering the need forlong-distance signal propagation. For this reason, weare conducting basic studies on signal propagation by
performing actual signal-propagation measurements
to formulate a radio propagation model. We are also
clarifying the feasibility of applying multiple-input
multiple-output (MIMO) transmission technology tosingle-carrier systems in VHF band systems.
3. Millimeter-wave band wireless systems
In this section, we introduce studies using the millimeter-wave band as an approach to using high-frequency bands. In particular, we describe wirelessentrance technology and RoF technology as countermeasures to rising volumes of traffic in urban areas.
NTT Technical Review

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Optical fibers are commonly used when connecting
many small-cell remote base stations. However, it isexpected that an even greater number of small-cell
remote base stations will be used in the future, suggesting that wide-band and high-frequency wirelessentrance technologies will become essential. We can
expect efficient construction of the front-haul section
through flexible use of wireless entrance technologies in combination with optical fibers. Therefore, we
experimentally verified the performance of a wireless-entrance approach using millimeter waves.
Assuming a front-haul interface based on a function
assignment between a central base station and remotebase stations and a transmission speed within 10
Gbit/s, we evaluated wireless transmission performance intervals of 20 and 50 m. The experimental
results indicated that no major degradation in transmission performance could be found compared withusing optical fibers.
R&D is also progressing in wireless systems using
high-frequency-band analog RoF for directly converting millimeter-wave radio signals to optical signals for transmission through optical fibers. Highfrequency-band analog RoF technology uses radiosignal-processing in a central base station and connects
52

Feature Articles(a) Analog RoF technology

E/O
conversion

Opticalfiber

O/E
conversion

Original radio signal

Remote basestation(2) Extract original radio signal
simply by O/E conversion

Radio signal
Central base station(1) Transmit optical signal in the form of radio
signal (intensity modulation of optical signal)(b) Function assignment between central base station and remote base station through analog RoF

Wireless system operation achieved bydealing only with the central base station sideNTT
Wireless system 1
Signal processing
Wireless system 2
Signal processing

Integration of signal
processing specific todifferent wireless systems

Access to multiple wirelessterminals by remote beam control

Multiple wirelesssystems share a single
remote base station

Remote basestationWireless system 1
Wireless terminal

Analog RoF interval

Central base station

Wireless system 2

E/O: electrical to optical
O/E: optical to electricalFig. 4. Wireless communication system using RoF.

antennas to a remote base station via optical fiber(Fig. 4). With this scheme, we can expect the remotebase-station side to take on a simplified and lowpower configuration. When many remote base stations come to be deployed in the future, this scheme
will make it possible to achieve remote beam control
by implementing beam forming technology, which isessential to millimeter waves, only in central basestations. These millimeter-wave technologies arebeing investigated and developed for application in
the beyond 5G (fifth-generation mobile communications) era.
4. Satellite communications
We now describe our R&D of satellite communication systems. In the aftermath of the Great East Japan
Earthquake, attention turned to the distinctive features of satellite communication systems such as
wide-area and immediate communications. ThereNTT Technical Review

Vol. 18 No. 4 Apr. 2020

fore, we developed high-efficiency signal-processing
equipment for earth stations applicable to remoteislands and anti-disaster approaches. Satellite communications are in the midst of a great transformation
on a global scale. We are investigating the applicationof communications not only to stationary satellites
used in conventional communication systems but also
to LEO satellites. To explore the expansion of satellite communications, we are studying a MIMO transmission technique for applying MIMO technology to
LEO satellite systems. A model of MIMO transmission using a LEO satellite is shown in Fig. 5. The
basic results of this study indicate that transmission
capacity can be increased when using multiple antennas on a LEO satellite to achieve large-capacity performance for downlinks. We intend to continue our
R&D efforts in this area to find new uses of space.

53

Feature Articles

Large-capacity observation data

IoT and observation satellite data canbe used through LEO satellites.

Large-capacity satellite downlinks can be usedthrough MIMO transmission technology.

Large-capacity downlinks
through LEO satellite MIMO

Accommodates manysatellite IoT devices
Basestations

IoT: Internet of Things

Fig. 5. LEO satellite MIMO transmission.

5. Wireless LANs
In this section, we describe recent R&D activities
focusing on wireless LANs. While participating in theIEEE 802.11 committee and a variety of organizations
such as the Association of Radio Industries and Business (ARIB), we have been promoting R&D of wireless LANs not only in terms of technology but also ofstandardization and regulations. Wireless LANs aredramatically advancing not only as means of communications, as in conventional LANs using unlicensed bands, but also in regards to usage scenarios.
A wireless LAN is a system that greatly extends theuser’s reach. In addition to advanced specifications
such as high-quality, large-capacity, and low-latencytransmission, wireless LANs are contributing to a

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

variety of services through new deployments in noncommunication areas such as positioning, visualization of radio quality, and object detection by radio
waves. Recent verifications involving crowds ofaround 10,000 people at large stadiums or exhibit
halls have demonstrated the huge potential of allmember new-experience-type events, which use alarge-scale Wi-Fi network environment to enable asimultaneous content-sharing experience.
6. Future outlook
For future study, we plan to continue our R&D
activities to provide our customers with wireless services, which are all the more convenient, while supporting a wide variety of existing wireless services.

54

Feature Articles

Takeshi Onizawa

Executive Research Engineer, Supervisor, Executive Manager - Wireless Entrance
Systems Project, NTT Access Network Service Systems Laboratories.
He received a B.E., M.E., and Ph.D. from Saitama University in 1993, 1995, and2003. Since joining NTT in 1995, he has been engaged in the R&D of personalcommunication systems and high data rate wireless LAN systems, future wirelessaccess systems and radio propagation. He is now in charge of management strategies
of wireless communication systems. He received the Best Paper Award, Young
Investigators Award, and Achievement Award from the Institute of Electronics,
Information and Communication Engineers (IEICE) in 2000, 2002, and 2006,
respectively. He received the Maejima Hisoka Award in 2008. He also received theBest Paper Award in International Symposium on Antennas and Propagation (ISAP)in 2016. He is a senior member of IEICE and a member of the Institute of Electricaland Electronics Engineers (IEEE).

NTT Technical Review

Vol. 18 No. 4 Apr. 202055

Regular Articles

Compact Silica-based 16 × 16
Multicast Switch with Surface Mount
Technology for PLCsAi Yanagihara, Keita Yamaguchi, Takashi Goh,and Kenya Suzuki
Abstract

We propose an electrical interconnection structure in which electrical connectors are directly solderedon a silica-based planar lightwave circuit using surface mount technology. A compact 16 × 16 multicast
switch (MCS) having five electrical connectors was successfully demonstrated. We reduced the chip size
to half that made with conventional wire bonding technology. We obtained satisfactory solder contacts
and excellent switching properties. These results indicate that the proposed structure is suitable for largescale optical switches including MCSs, variable optical attenuators, and dispersion compensators.
Keywords: optical switch, planar lightwave circuit (PLC), surface mount technology (SMT)

1. Introduction
Optical network automation is useful for accommodating increases in mobile and/or datacenter traffic
and network restoration after serious disasters. In
mobile and datacenter applications, hot and cold
spots appear in different areas of networks at different
times, which results in poor network resource utilization. Additional bandwidth or link assignments to hot
spots will contribute to improving resource utilization, leading to a reduction in the capital expenditure
for additional investment. Rapid network restoration
after disasters is also required. Optical links should
be changed from dead paths to live ones as fast as
possible. Network automation is achieved by software-defined networking and reconfigurable optical
add/drop multiplexing (ROADM) with colorless,directionless, and contentionless (CDC) functions.
Multicast switches (MCSs) are enablers for the CDCROADM system [1–3]. Large-scale MCSs, such as
those with 16 degree ports and 16 transponder ports,
are important for handling a large number of signals
to make the network more flexible.
Silica-based planar lightwave circuits (PLCs) are
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

suitable for large-scale optical switches because they
have many advantages, such as low propagation loss,
high extinction ratio, and facilitation of density integration [4–6]. M-degree ports and N-transponder
ports (M × N) MCSs are composed of M × N switch
elements. Each switch element consists of MachZehnder interferometers (MZIs), which are driven bya heater on one of its arms through the thermo-optic
effect [7]. To supply the switching power to heatersfrom a driving circuit on a printed circuit board(PCB), the switch elements are equipped with electrical wires and electrical pads. Although we need todensely integrate switch elements to fabricate largescale MCSs, the large area of the electrical wiring
limits their number. Thus, we need to reduce the areaof the electrical wiring to enable high-density integration of the switch elements. Several compact opticalswitches that overcome this problem have beenreported. One uses the interposer for electrical interconnection [8]. This is suitable for silicon photonics
but not appropriate for larger silica-based PLCs
because such PLCs have a larger chip size and thedifference in the thermal expansion coefficients
between a PLC and the interposer cannot be ignored.
56

Regular Articles

(b)

(a)
PLC chipElectrical connectors

Optical fibers
B

B’
Electrical connector
Lead pin
SolderElectrode
pads
PLC

Electrode pad

PCBElectrical cables

Fig. 1. (a) Top-view schematic of our proposed structure and (b) cross-sectional schematic of B-B’ in (a).

(a)

(b)

Switch element
Electrode pad
Electrical wire

Fig. 2. Conventional (a) and proposed (b) structures of electrical wiring in the PLC chips of an M × N matrix or MCS.

In this article, we propose an electrical interconnection structure in which electrical connectors are
directly mounted on a PLC using surface mount technology (SMT). We fabricated a 16 × 16 MCS with our
proposed structure. The chip size of the PLC was successfully reduced to half that of a conventional chipusing the bonding wire method. We obtained excellent switching performance.

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

2. Proposed structure
Figure 1(a) shows a top-view schematic of our
proposed structure. The electrical connectors are
directly mounted on the silica-based PLC chip. The
lead pins of the electrical connectors are soldered tothe electrode pads on the PLC surface, as shown in
Fig. 1(b), which is a cross-sectional view at B-B’ in
Fig. 1(a). The PLC and PCB are connected to eachother with electrical cables, such as flexible printcircuits (FPCs). Figure 2 shows the designs of electrical57

Regular Articles

60

±6 

Number of paths

50
40
30
20
10
0

−10 −8 −6 −4 −2 02
4
6
Variation in resistance ()810Fig. 3. Photograph of fabricated 16 × 16 MCS.
Fig. 4. Variation in measured resistance.

wiring in the PLC chips of an M × N matrix or MCS,
which are for a conventional electrical connection
structure and our proposed structure, respectively.
Conventionally, as shown in Fig. 2(a), a PLC and
PCB have been connected electrically using a generalwire bonding method. Electrode pads are arranged on
the edge of both the PLC and PCB to bond them withgold wire. In this design, long electrical wirings arearranged from each heater to each electrode pad on
the edge of the PLC. Thus, the arrangement of theelectrical wiring on the PLC becomes complicatedand its area increases with the number of switch elements, which limits the miniaturization of the chip.
On the other hand, the arrangement of electrical wiring with the proposed structure is simple, as shown in
Fig. 2(b). As the electrode pads can be placed near theswitch elements, the length of electrical wiring can beshortened. Therefore, this structure enables us toreduce the area of the electrical wiring and integrate
the switch elements more densely. The proposed
structure also offers advantages such as automatic
fabrication because the electrical connectors can bemounted on the PLC using general SMT widely usedin the assembly of electrical devices. The proposed
structure also makes it possible to mount the connectors automatically at the wafer level, making it suitable for mass production.
3. Experiment
3.1 Fabrication
Figure 3 shows a photograph of the 16 × 16 MCS
chip with the proposed structure. The chip was fabricated using the conventional silica-based PLC fabrication process. The 256 switch elements, consistingof MZIs and heaters, are regularly arranged in the
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

PLC, and each heater is connected to the electrodepad with electrical wires. The electrical wires areshorter than those in a conventional PLC switch withwire bonding because the electrode pads are placednear the switch elements. Therefore, the area of theelectrical wiring in the chip is greatly reduced. The
chip size is 23.5 × 72 mm. We estimated that it is twotimes smaller than a conventional 16 × 16 MCS withwire bonding. After PLC fabrication, five electricalconnectors are mounted on the PLC chip with solderusing SMT at the 6-inch wafer level. After AgSnCu(Ag: silver, Sn: tin, Cu: copper) solder paste has been
patterned on the electrode pads by screen printing,the electrical connectors are mounted and soldered by
the standard reflow process. As there are 256 heaters
in the 16 × 16 MCS chip, we mount five electricalconnectors on it. Since general electrical connectors
have approximately 50 to 80 pins, we can construct alarge-scale MCS by increasing the number of mounting electrical connectors. Therefore, our structure isscalable for constructing much larger MCSs.
3.2 Electrical characteristics
We measured the resistance of the 256 switch elements by connecting the PLC and PCB with an FPC,
as shown in Fig. 1(a). Figure 4 shows the variation in
the average resistance of the 256 heaters. This variation includes the variation in the heaters, electricalwires on the PLC, soldered connection parts between
the electrode pads in the PLC and PCB and the leadpins of the electrical connectors, and the contacts
between the FPC and electrical connectors. The
variation in the average resistance was less than ±5 Ω
and 3σ (σ: standard deviation) was 6.8 Ω. In our
switch module, the variation needs to be less than ±658

Regular Articles

(b)
80

−20
Number of paths

Transmittance (dB)

0

ON
OFF

−40
−60
−80

−100

(c)

0

32

64

96
128 160
Path number

192

224

256

60

80

Avg.: 15.2 dB
3: 1.4 dB
N: 256
Number of paths

(a)

40

20

0
13.6 14.4 15.2 16.0 16.8
Loss (dB)

Avg.: 57.6 dB
3: 4.5 dB
N: 256

60

40

20

0

50 52 54 56 58 60 62 64
Extinction ratio (dB)

Fig. 5. (a) On-state and off-state transmittance for all 256 paths, and histograms of (b) insertion loss and (c) extinction ratios.

Ω to satisfy the need to keep the variation in insertion
loss of all switch elements within ±0.1 dB. Thus, thisresult indicates that satisfactory connections wereobtained for all soldered parts. We estimate that thisvariation in the resistance resulted in the variation in
the length of the electrical wires. Thus, this variationin switch resistances can be reduced by changing thewidth or length of the electrical wires.
3.3 Optical characteristics
We evaluated the switching characteristics of all
256 connections from 16 degree ports to 16 transponder ports at the wavelength of 1550 nm. By measuring transmission changes with electric power applied
to the heater, we obtained clear switching characteristics for all 256 paths. Figure 5(a) shows the measured on- and off-state transmittance for all 256
paths. The average switching power per switch element was 0.24 mW. It was clearly observed that all
the paths operated correctly, proving that our proposed structure works well. Figures 5(b) and (c)show a histogram of the insertion loss and extinction
ratios for all 256 paths. The average insertion loss andstandard variation were 15.2 and 1.0 dB, respectively.
The insertion loss includes intrinsic loss of 12 dB.
Thus, the excess loss is as small as 3.0 dB on average.
The average and variation in the extinction ratio were
53 and ±5 dB, respectively. As described above, all
the paths operated correctly, proving that the proposed structure works well.

4. Conclusion
We demonstrated a compact 16 × 16 MCS using
our new electrical interconnection structure based on
SMT. Five connectors are soldered directly to the
PLC by the standard reflow process used for electric
devices. We successfully reduced the chip size to 23.5
× 72 mm, which is two times smaller than a conventional chip with wire bonding. We obtained satisfactory solder contacts and excellent switching properties. These results indicate that our proposed structure
is suitable for large-scale MCSs and this new electrical interconnection method with SMT can be applied
to other silica-based PLC devices.
References
[1]

[2]

[3]

[4]

[5]

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

Y. Sakamaki, T. Kawai, T. Komukai, M. Fukutoku, T. Kataoka, T.
Watanabe, and Y. Ishii, “Experimental Demonstration of Multi-degree
Colorless, Directionless, Contentionless ROADM for 127-Gbit/s
PDM-QPSK Transmission System,” Opt. Exp., Vol. 19, No. 26, pp.
B1-B11, 2011.
T. Watanabe, K. Suzuki, T. Goh, K. Hattori, A. Mori, T. Takahashi, T.
Sakamoto, K. Morita, S. Sohma, and S. Kamei, “Compact PLC-based
Transponder Aggregator for Colorless and Directionless ROADM,”
Proc. of Optical Fiber Communication Conference (OFC), OTuD3,
Los Angeles, CA, USA, Mar. 2011.
T. Watanabe, K. Suzuki, and T. Takahashi, “Silica-based PLC
Transponder Aggregators for Colorless, Directionless, andContentionless ROADM,” Proc. of OFC, OTh3D.1, Los Angeles, CA,
USA, Mar. 2012.
T. Shibata, M. Okuno, T. Goh, T. Watanabe, M. Yasu, M. Itoh, M.
Ishii, Y. Hibino, A. Sugita, and A. Himeno, “Silica-based Waveguidetype 16 × 16 Optical Switch Module Incorporating Driving Circuits,”
IEEE Photon. Technol. Lett., Vol. 15, No. 9, pp. 1300–1302, 2003.
S. Sohma, T. Watanabe, N. Ooba, M. Itoh, T. Shibata, and H.
Takahashi, “Silica-based PLC Type 32 × 32 Optical Matrix Switch,”
The 32nd European Conference on Optical Communication (ECOC59

Regular Articles

[6]

[7]

2006), Paper OThV4, Cannes, France, Sept. 2006.
M. Takahashi, S. Yamasaki, Y. Uchida, and J. Hasegawa, “Compact
and Low-loss ZrO2-SiO2 PLC-based 8 × 8 Multicast Switch for CDCROADM Application,” IEEE J. Lightw. Technol., Vol. 34, No. 8, pp.
1712–1716, 2016.
T. Goh, A. Himeno, M. Okuno, H. Takahashi, and K. Hattori, “Highextinction Ratio and Low-loss Silica-based 8×8 Thermooptic Matrix

Ai Yanagihara

Engineer, NTT Device Innovation Center.
She received a B.E. and M.E. in electricalengineering from Sophia University, Tokyo, in2013 and 2015. She joined NTT in 2015. She is amember of the Institute of Electronics, Information and Communication Engineers (IEICE).

Keita Yamaguchi

Research Engineer, NTT Device Innovation
Center.
He received a B.S. and M.S. in physics from
University of Tsukuba, Ibaraki, in 2009 and2011, and a Dr. Eng. in computational scienceand engineering from Nagoya University in
2019. In 2011, he joined NTT. His research interests include silica-based waveguides. Dr. Yamaguchi is a member of IEICE.

NTT Technical Review

Vol. 18 No. 4 Apr. 2020[8]

Switch,” IEEE Photon. Technol. Lett., Vol. 10, No. 3, pp. 358–360,
1998.
K. Tanizawa, K. Suzuki, M. Toyama, M. Ohtsuka, N. Yokoyama, K.
Matsumaro, M. Seki, K. Koshino, T. Sugaya, S. Suda, G. Cong, T.
Kimura, K. Ikeda, S. Namiki, and H. Kawashima, “Ultra-compact 32
× 32 Strictly-non-blocking Si Wire Optical Switch with Fan-out LGA
Interposer,” Opt. Exp., Vol. 23, No. 13, pp. 17599–17606, 2015.

Takashi Goh

Senior Research Engineer, NTT Device Innovation Center.
He received a B.S. and M.S. in electronics andcommunication engineering from Waseda University, Tokyo, in 1991 and 1993. In 1993, hejoined NTT Opto-electronics Laboratories,
where he was involved in research on silicabased PLCs. From 2002 to 2004, he was engaged
in the development of optical communication
systems in NTT Innovation Laboratories. From2004 to 2017, he was with NTT Photonics Laboratories and Device Technology Laboratories,
where he was involved in the research and development of integrated optical devices based on
PLC technology for optical transmission andoptical signal processing. He is currently withNTT Device Innovation Center. He received theYoung Engineer Award from IEICE in 2000. He
is a member of IEICE, the IEEE Photonics Society, the Japan Society of Applied Physics, and the
Physical Society of Japan.

Kenya Suzuki

Project Leader, Senior Research Engineer,
Supervisor, NTT Device Innovation Center.
He received a B.E. and M.E. in electrical engineering and a Dr. Eng. in electronics engineeringfrom the University of Tokyo, in 1995, 1997, and2000. He joined NTT in 2000. From September
2004 to September 2005, he was a visiting scientist at the Research Laboratory of Electronics,
Massachusetts Institute of Technology, USA.
From 2008 to 2010, he was with NTT Electronics
Corporation, where he was involved in the development and commercialization of silica-based
waveguide devices. Since 2014, he has been aguest chair professor at the Tokyo Institute ofTechnology. From 2018 to 2019, he lectured acourse of electric material at Meisei University,
Tokyo. He is also a chief director of photonic &electronic hybrid switching system research anddevelopment division of Photonics Electronics
Technology and Research Association (PETRA).
His research interests include optical circuitdesign, fabrication, integration, and signal processing. He received the Young Engineer Award
from IEICE in 2003. He is a member of IEICE,
the IEEE Photonics Society, and the PhysicalSociety of Japan.

60

Global Standardization Activities

Activities of the APT/TTC Bridging
the Standardization Gap Working
Group—Holding of Ideathons in
Cooperation with Universities inSoutheast Asia
Hideyuki Iwata
Abstract

The Bridging the Standardization Gap (BSG) Working Group of the Telecommunication Technology
Committee (TTC) of Japan has been implementing and promoting the spread of information-and-communication-technology-based solutions to address social issues in rural areas of Asian countries withsupport provided by the Asia-Pacific Telecommunity (APT). It has launched a platform designed to sharedata obtained at pilot sites in a number of countries, related to several fields including agriculture, fisheries, the environment, medical care, education, and disaster prevention. It held events at which ideas were
proposed on how to create new industries through the utilization of data across different industries. This
article presents an overview of these events.
Keywords: TTC, BSG, APT, ideathon

1. First ideathon
The first ideathon was held at the University of
Malaysia Sarawak in Kuching, Malaysia, on December 5 and 6, 2018.
1.1 oneM2M Workshop (pre-ideathon workshop)
On November 28, before the ideathon was held, a
lecturer from the University College of Technology
Sarawak in Malaysia, held a workshop for 70 students at the University of Malaysia Sarawak. He gave
an overview of oneM2M*, demonstrated how to set
up a oneM2M-compliant server and connect Internetof Things (IoT) devices to this server.
1.2 Ideathon@Malaysia
This ideathon was held over two days and wasattended by 76 students in 20 teams from the University of Malaysia Sarawak, and University College ofNTT Technical Review

Vol. 18 No. 4 Apr. 2020

Technology Sarawak (Photo 1). The teams were thenfurther divided into three groups and gave presentations and demonstrations in each group. The top teamin each group gave additional presentations in theplenary session, then the teams were ranked.
The titles of proposals and the areas targeted by theparticipating teams are shown in Table 1.
Since Kuching is a provincial city in Borneo, there
were few proposals addressing the problem of traffic
congestion. The most common topics were disasterresponse solutions to floods and forest fires andmedical issues, including problems with water quality.

*

oneM2M: A global organization that was established in 2012 bymajor standards development organizations aiming at developing
the requirements and specifications for machine-to-machine(M2M) and IoT technologies.

61

Global Standardization Activities

Photo 1. Scene from the awards ceremony at Ideathon@Malaysia.

Table 1. Titles of proposals and target areas at Ideathon@Malaysia.
No.
1

Title of proposal
Smart Indoor Hydroponic Planting

Area
e-Agriculture

Group

2

Smart Shopping System

Smart city

4896

3

IoT-based Water Quality Buoy Using oneM2M

e-Environment

Morphling
Keeper of the Light

4

Smart Badminton Stadium with Automatic Lighting System

Smart city

5

Health-monitoring System Using Motion and Pulse Sensor

Smart city

DGB

6

Parking Slot Availability Indicator

Smart city

Smart Park

7

Forest-fire Detector

e-Disaster

G-TECHNOVATORS

8

Drainage-system Sensors for Flood Prediction

e-Disaster management

IDeaITech

9

Flood Detection with Rain Sensor

Disaster

SMART LRB

10Narcolepsy Life Saver

e-Health

MedIT.com

11

Water-pollution Detection System

e-Health

Mind Bender

12

Vehicle RFID

Smart city

EE Prodigy

13

Smart Greenhousee-Agriculture

iGreen14

JAMS: Just Another Metering System

Smart city

TheBitJunkeys

15

Rainwater-collection System to Reduce Floods

e-Traffic, disaster

Alpha Minds

16

iWater Cleaner

e-Environment

Fantastic Four17

Smart Waste-management System

Smart city

HOTS

18

A+I: Mood-detecting Sensor

Smart city

LOTS

19

Forest-fire Detection Using ATIS

e-Agriculture

ZIPs

20

Life-saving System: e-Health, e-Traffic Management, Smart City Health, transportation, smart city Sffic

2. Second ideathon
The second ideathon took place at Ateneo deManila University, Manila, the Philippines, on March
6–8, 2019.

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

Award

QBF Ultimate

1st Prize

2nd Prize

3rd Prize

2.1 Technical Specifications Workshop
On March 5, the day before the ideathon was held,
Dr. Daniel of Ateneo de Manila University explainedand demonstrated to 26 students how to connect
oneM2M-compliant IoT devices to a oneM2M-compliant server.
62

Global Standardization Activities

Photo 2. Scene from Ideathon@Philippines.

Table 2. Titles of proposals, target areas, and awards at Ideathon@Philippines.
No.

Title of proposal

Area

Group

Preliminary
award

1

Potential of Smartphones in Disaster and Emergency Situations

Disaster

TriLocate2

Smart Analytics and Early-warning System that Forecasts Future Red Tideand Fish Kill Incidents

Aqua culture, disaster

Red Alert!

3

Fastest Route Cleared Smart Traffic-light Control System to Emergency
Vehicle Driver

Smart city, medicine

Lifeline

4

Provide Commuters with Accurate Estimates of Wait Times and Optimization
MovingSmart city, transportationof Train Use
Stations

5

Redistribute Foot Traffic to Save Time and Resources

Smart city

BOMS

Round 26

Food-supply Monitoring and Tracking System

Agriculture, health,logistics

Food
Enthusiasts

Round 2
/1st Prize

7

Real-time City-wide Pedestrian Traffic Monitoring and Mapping System

Disaster, smart city

Fast Pass

Round 2

8

Improve Security, Portability, and Overall Efficiency of Medical Procedures

Smart city, health

MED ID

Round 2
/2nd Prize

9

Monitor Pollen and Dust Distribution

Smart city, healthpolleNATION

10Provide New Innovative Sets of Data Concerning Human Activities within
Homes

Smart home

Home Vita

11

Monitor Trash in Drainages

DisasterImage Pulse

12

Patient-monitoring System

HealthMonitAir

13

Solve Problems of Environmental Pollution through Smart Trash Collection

Smart city

Waste Watch

14

Monitor Health and Status of Its Users Using Smart Watch

Smart city

Ligaw

15

Intersection Data Collection and Processing System to Solve Traffic Problem Smart city

IDCPS

16

Track-energy Consumption by Providing Real-time, Aggregate andPre-appliance Data and Heuristics

Smartr

2.2 Ideathon@Philippines
Before the final ideathon (Round 2), an elimination
round (Round 1) was held at Ateneo de Manila University with 34 students in 16 teams from the university, and 7 teams were selected (Photo 2). The final
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

Smart home, energy

Round 2
/3rd Prize

Round 2Round 2

ideathon (Round 2) was held with judges from Japan,
Malaysia, and the Philippines.
The titles of proposals, target areas of the participating teams, and awards presented at Ideathon@Philippines are shown in Table 2.
63Global Standardization Activities

Photo 3. Scene from the awards ceremony at Ideathon@Indonesia.

Since this region is prone to natural disasters, many
proposals addressed disaster-related issues and issues
related to a shortage of medical facilities and institutions. Also, many of the proposed solutions required
the involvement of the entire city.
3. Third ideathon
The third ideathon was convened at the Bandung
Institute of Technology, Bandung, Indonesia, on
November 8–9, 2019.
Three people from the Telecommunication Technology Committee (TTC) Bridging the Standardization Gap (BSG) Working Group, two from Malaysia,
and two from the Philippines participated in and supported the event. Twenty faculty members and students from the Bandung Institute of Technology also
assisted.
3.1 Workshop on oneM2M
Vice-Chair Kazunori Tanikawa of the TTC BSG
Working Group gave an overview of oneM2M toenable the participants to use the internationally standardized platform for providing information andcommunication technology (ICT) solutions. Also, theUniversity College of Technology Sarawak handedout oneM2M-compliant IoT tool kits and gave a tutorial on how to connect them to a oneM2M-compliant
server.
3.2 Ideathon@Indonesia
This ideathon was attended by 57 people in 19
teams. Before the final ideathon (Round 2), an elimiNTT Technical Review

Vol. 18 No. 4 Apr. 2020

nation round (Round 1) was held by the local operating organization, and 10 of the 19 teams were selected. Six people from the TTC BSG Working Groupand two from the local operating organization were
judges and evaluated the presentations (Photo 3).
The titles of proposals, target areas of the participating teams, and awards given by Ideathon@Indonesia are shown in Table 3.
The theme of many presentations was how toresolve traffic congestion, which is a common social
issue in Asian cities. In addition, since Indonesia isstudying how to transfer the capital from Jakarta to
Kalimantan (Indonesian part of Borneo), there was a
proposal on how to control peatland fires, a problem
affecting Kalimantan.
4. Future prospects
In planning ideathons, we hoped to see proposals
aimed at creating new industries by combining data
across different industries. However, most proposals
presented in these ideathons were related to solving
impending social issues with ICT. Since our priorexplanation seems to have been insufficient, it will benecessary to clarify the themes we would like participants to address in upcoming events. We plan to holdideathons in other countries in the Asia-Pacific region
and aim to expand these activities so that they will
become common events in Asia.
Cultivation of human resources skilled in ICT isessential if we are to make regional economies thrive.
Together with universities in Japan, we will contribute to this initiative through these activities.
64

Global Standardization Activities

Table 3. Titles of proposals, target areas, and awards given by Ideathon@Indonesia.
No.

Title of proposal

1

Independent Household Waste Processing and Online-based Waste
Management

Area

Preliminary

Environment

2E-MONEY with Tracking System in Toll Roads

Safety, transportation

3

Peatland Humidity-control System for Forest-fire Handling

Environment

Round 24

Firetruck Routing System

Transportation, safety

Round 2

5

Coal Mining Supervision for Borneo 2025

Safety, efficiency, mining industry

6

Smart Zebra Cross

Smart cities, road safety, IoT

Round 2

7

Smart Electricity

Smart cities

Round 28

Integrated Waste-quality-monitoring System for Borneo: Integrating the
Eco-friendly Trash Can and GoTrash Application

Environment, health, smart cities

Round 2

3rd Prize

Round 2

2nd Prize

9

WeHelp: Disaster-management App

Safety10

Smart Traffic Light Using IoT and Cloud Computing for Protanopia

Smart city, cloud computing, IoT

11

Borneo in 2025 Be a Smart City in Public Transportation

Smart city, transportation

12

Traffic Control and Monitoring

Transportation

13

E-Commerce for Fisherman

E-Commerce

14

Kalimantan (Borneo) Smart-city Car Limiter 2025

Traffic, environment, health

15

UAV Swarming Usage to Conserve Borneo’s Forest

Environment

16

Waste Management

Environment

17

Integrated Household Photovoltaic in a Smart City for New Capital Issue Smart city, green energy

Round 218

Crowd Estimation for Smart Transportation

Smart city, transportation

Round 219

Smart Building

Smart city

Round 2Award

1st Prize

Round 2

Hideyuki Iwata

General Manager, Standardization Strategy,
Research and Development Planning Department, NTT.
He received a Ph.D. in electrical engineeringfrom Yamagata University in 2011. From 1993 to
2000, he conducted research on high-density andaerial optical fiber cables at NTT Access Network Service Systems Laboratories. Since 2000,
he has been responsible for standardization strategy planning for NTT research and development.
He has been a delegate of the International
Electrotechnical Commission (IEC) Subcommittee 86A (optical fiber and cable) since 1998 andof the International Telecommunication Union Telecommunication Standardization Sector(ITU-T) Telecommunication Standardization
Advisory Group (TSAG) since 2003. He is avice-chair of the Working Group on Policy andStrategic Coordination and the Expert Group on
Bridging the Standardization Gap in the AsiaPacific Telecommunity Standardization Program(ASTAP). He received an award from the IEC
Activities Promotion Committee of Japan in
2004, the ITU Association of Japan (ITU-AJ)
International Activity Encouragement Award in2005, an ITU-AJ International Cooperation
Award in 2012, an award for contributions to an
ICT development project at the APT ICT Ministerial Meeting in 2014, the ITU-AJ Accomplishment Award in 2018, and TTC Chairman’s Prizein 2019.

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Vol. 18 No. 4 Apr. 202065

Practical Field Information about
Telecommunication Technologies
Practical Field Information about Telecommunication Technologies

Troubleshooting Facsimile
Communication by Analyzing IP and
POTS Protocols
Technical Assistance and Support Center, NTT EAST
Abstract

This article presents an investigation on a problem in which a part of a fax image is blanked out using
various measurement tools. This is the fifty-seventh article in a series on telecommunication technologies.
Keywords: fax, packet capture, key telephone system

1. Introduction
Along with the widespread use of fiber-optic broadband services, use of services and configurations ofcustomer’s network have become complicated. Thus,
several problems have occurred due to setting mistakes or protocol failures. The Network Interface
Engineering Group at the Technical Assistance andSupport Center (TASC), NTT EAST, is in charge oftechnical support for Internet protocol (IP) services
and public switched telephone network (PSTN) services such as plain old telephone services (POTS).
Our mission is to quickly solve a problem in the fieldby finding the cause of the problem and suggesting
appropriate measures to prevent such a problem forre-occurring.
To accomplish our mission, we developed andinstalled several tools for solving problems in our
telecommunication services. For IP-related services,
IP-packet capture and analysis tools are used toobtain IP packets in an IP section. For PSTN services,
however, a signal-analysis method involving an oscilloscope, analog-waveform recorder (Memory
HiCorder), and integrated services digital network(ISDN) protocol analyzer are used. In an investigaNTT Technical Review

Vol. 18 No. 4 Apr. 2020tion of terminals, especially for key telephone systems, we developed a signal-analysis tool for our key
telephone system, i.e. α series key telephone system(Fig. 1).
In this article, we introduce a facsimile troubleshooting case in which a fax image is blanked out.
First, we present the details of the problem thenexplain how to investigate it using our tools. Second,
we present the results of analyzing the data obtained
from these tools. Finally, we explain the cause of the
problem derived from our investigation.
2. Summary of problem andinvestigation method
The configuration of the network in customer
premises we investigated is shown in Fig. 2. The network had two parts, the parent office and branch site.
These sites connected to each other with a virtualprivate network (VPN) service to extend the network,and each site connected to a HIKARI IP-telephoneline to use public telephone services. A multifunction
printer manufactured by another company was connected to each part and provided facsimile and printerfunctions. However, regardless of site location or line
66

Practical Field Information about Telecommunication Technologies

Office-command
analysis
support toolHome
Wireless LAN tester

PHS
DCL

NTT
telecommunication
services

PHS analyzer
ISDN

Fiber-optic Internet
IP telephone
Virtual private network
IP television
Data storage
Subscriber telephone
International
telephone
Dedicated lines

GW, etc. ONU

Telephone Key telephonesystem 
masterequipment unit

ISDN multi-line analyzer

Wireless LAN terminal
Wi-Fi

IP

IP
RouterONU

AnalogAnalog line

Modem

PC

HGW

Telephone
Oscilloscope

Cap-two (Packetcapture tool)

Memory HiCorder

Analog Logger

ONU: optical network unit
PC: personal computer
PHS: personal handy-phone system

DCL: digital cordless telephone
GW: gateway
HGW: home gateway
LAN: local area network

Fig. 1. Effective maintenance-support tool for troubleshooting.

HIKARI
telephone
network

Parent site

ONU

VPN

NX-S
NX-

ONU

Branchsite

VPN

Cap-two measurement
point
Analog-Logger
measurement point

Multifunction printerM(of another manufacturer)

Reception path of fax
signalPoEHUBE
FV-1000
FV-1- 0

Single phone
adapter

Multifunction printer(of anothermanufacturer)

4BRU: broadband router unit
IPEU: IP extension unit
SLU: single phone-housing unit

Branchsite

FV-1000
-1

4BRU
4B
U

PoEHUB
FV-1000

ONU
O
Router
o

IPEU

SLU

SLU

IPEU

FV-1000

ONU
O
U
NX-S

Router4BRU

HIKARI
telephone
network

Parent site

Cap-two measurement
point
Analog-Logger
measurement point

Multifunction printer(of another manufacturer)

Reception path of fax
signalSinglee phonedaadapter

Multifunction printer(of anothermanufacturer)

4BRU: broadband router unit
IPEU: IP extension unit
SLU: single phone-housing unit(a) When receiving a call at the parent site(b) When receiving a call at the branch site

Fig. 2. Configuration of customer network and measurement points.

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Practical Field Information about Telecommunication Technologies

When normal

Printing
direction

When the problem occurs

Printing
direction

Blank partFig. 3. Output of multifunction printer when a problem occurs.

Features• Easy connection• Start packet capture at the push of a button (skill-free operation)• Capable of capturing packets at two locations simultaneously• Long-term monitoring possible (480-GB large-storage capacity)
Back

Internet, etc.
ONU

Router, HGW, etc.

Terminals, etc.

Fig. 4. Packet-capture tool Cap-two (developed by TASC).

used (internal or external), the received faxed image
was sometimes partially blank, as shown in Fig. 3.
According to a declaration from the customer, theproblem (i.e., a partially blank fax) occurred about
once a week, and its cause could not be found out
even though the manufacturer of the multifunction
printer investigated it. Moreover, NTT had been confirming and changing the settings of the optical network unit (ONUs), key telephone system (αNXtypeS), and VPN-terminating equipment (FV-1000)
connecting each site as well as replacing terminals,
etc. However, the problem was not resolved, so we
conducted an on-site investigation.
In the investigation, measurement tools (listed
below) were installed along the receiving paths of the
fax signal arriving by an external line to acquire andanalyze IP packets and signals passing along eachpath. As a result, the fax communication was correctat each measurement point (Fig. 2). Since occurrenceof the problem was rare, we decided to carry out longNTT Technical Review

Vol. 18 No. 4 Apr. 2020

term measurement by using our tools.
(1) Collection of IP packet data from network
For collecting IP-packet data from the customer’s
network, we used a packet-capture tool called Captwo (Fig. 4), which is a dedicated device for easilycollecting IP packet data without requiring any special skills.
(2)	Collection of electrical signals (waveform data)from analog lines
To collect waveform data from analog lines, we set
an analog-waveform recorder, called Analog Logger,on the analog telephone line. The features of the logger are shown in Fig. 5.
Analog Logger is a dedicated device for collecting
electrical signals (waveform data) from analog lines.
It has a registered jack (RJ) connector that can be easily inserted and connected to the analog line and canbe used for automatic measurement without requiring
any skills.
(3) Analysis of fax signals
68

Practical Field Information about Telecommunication Technologies

Features• Easy connection• Automatic measurement start at the push of a button(skill-free operation)• Lightweight: 1 kg or less
• Low power consumption: 10 W

Back

OUT IN

Switchor GW(Analog
port)

RJ connector

RJ connector

Analog line

Fig. 5. Analog Logger (developed by TASC).

Waveform

Fax
sequence
Packet
data

Audio
data
Image

Waveform
data

Fig. 6. Facsimile Communication Analyzer (commercial software).

The commercially available software Facsimile
Communication Analyzer ES-200 (by Egretcom) wasused to analyze the fax signals. This software cananalyze a facsimile sequence and decode a facsimile
image from audio files (wav files/au files) that record
the facsimile signal in the line, as shown in Fig. 6.
We obtained two types of waveform data from themeasurement. One is the data converted from IP
packets obtained from the IP section, and the other isthe data from the analog lines. By comparing thesedata using the software, we can evaluate the facsimile
sequence and decoded facsimile image obtained fromboth IP and analog sections.
In this investigation, we sent the measurement tools(Cap-two and Analog Logger) to on-site service personnel, and these tools were installed and operated bythose personnel. After the blank-fax problem
occurred, the tools were sent to the TASC for analyzing the measured data.
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Vol. 18 No. 4 Apr. 2020

3. Estimation of the cause of blank-fax problem
One month after installation of the tools, we recognized that the problem occurred twice (i.e., two blankfaxes were received). The fax sequence as shown in
Fig. 7 were checked when the problem occurred. As
a result, the following four points were clarified.
(1)	After successfully completing the call setup
and pre-message procedure, the sender divides
the image information and sends it.
(2)	After all the split-image information is transmitted, the partial page signal - end of procedure (PPS-EOP) signal is transmitted from thesender.
(3)	The multifunction printer is disconnected
after it does not respond to the PPS-EOP signal.
(4)	The multifunction printer outputs a blank fax.
When the received image was decoded from the69

Practical Field Information about Telecommunication Technologies

NX-S

ONU
IP section

Multifunction printerAnalog section

Call setup/pre-message procedure
Transmit splitimage information

Image information

Multi-page signal (PPS-MPS)
Message-confirmation (MCF)
Image information

End-of-procedure signal (PPS-EOP)
No
response

MCF

Facsimile Communication
Analyzer

Images without blank parts can be decodedfrom the measured data in the IP and analog sections.

Output an image
with blank parts

Fig. 7. Sequence of fax signals when blank-fax problem occurs.

packet and waveform data measured in the IP andanalog line sections, respectively, the images received
in both sections were successfully decoded. It istherefore concluded that no abnormality occurred in
the fax signals transmitted via the sections subject tomaintenance by NTT. Moreover, the multifunction
printer did not respond to the proper signal it should
be responding to; therefore, it is confirmed that theblank facsimile image occurred due to the setting/function of the multifunction printer. According to
the results of the investigation, the customer requested the manufacturer of the multifunction printer toreinvestigate the problem. After reinvestigation was
carried out, the blank-fax problem was eliminated.

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

4. Conclusion
In this article, a troubleshooting case of facsimile
communication was presented as an example of problems in a complicated customer’s network. It was
shown that by using Cap-two and Analog Logger(developed by the TASC) and commercially available
software (Facsimile Communication Analyzer) toanalyze the fax signal, it was possible to identify thecause of the problem in the network combined withIP and analog system. The TASC will continue tosolve problems in the field by supporting service personnel with our technical knowledge and developing
useful tools.

70Information

Event Report: Tsukuba Forum2019
Tomoyuki Nomura, Yusuke Koshikiya, Motoharu Sasaki,
and Ikuko Takagi
Abstract

Tsukuba Forum 2019 was held on October 31 and November 1. The theme of the forum was “Supporting the present, shaping the new era—World-leading technology for creating services and field frontline technology for transforming operation/maintenance.” This article gives a brief overview of the
speeches and exhibits presented at the forum.
Keywords: Tsukuba Forum, overview of speeches, overview of exhibits

1. Introduction
The main theme of Tsukuba Forum 2019 was “Supporting the present, shaping the new era—Worldleading technology for creating services and field
front-line technology for transforming operation/
maintenance.” It was held with the intention of creating a smart world with NTT as Your Value Partner as
it looks back on network access technologies thathave supported society to date and pioneers newaccess networks of the future. In addition to NTT
Access Network Service Systems Laboratories (ASLabs), 105 organizations, including co-hosting organizations and NTT Group companies (Table 1), participated. They introduced and exhibited the latest
research and development (R&D) and technologicaltrends.
2. Overview of speeches
The two keynote speeches were given at the Tsukuba International Congress Center on the first day.
They were relayed from the main convention hall of
Tsukuba International Congress Center to a venue at
the NTT Tsukuba R&D Center. The speeches werereceived by a large audience.

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

2.1 Keynote speech 1
Mr. Motoyuki Ii, senior executive vice president
and representative member of the Board of NTT, gavea speech titled “Towards Social Infrastructure Sharing” (Photo 1). For details, see the article in this issue[1].
2.2 Keynote speech 2
Mr. Naoki Shibutani, senior executive vice president and representative director of NTT EAST, gavea speech titled “Shaping Prosperous Future throughRegional Innovation” (Photo 2). For details, see thearticle in this issue [2].
3. Workshops
On the second day of Tsukuba Forum 2019, workshops were held at AS Labs. A business unit manager
of NTT Advanced Technology and two project managers from AS Labs conducted the workshops(Photo 3).
3.1 Workshop 1
Mr. Kazuo Kitamura, business unit manager of the
AI and Robotics Business Headquarters, Robotics
Solutions Business, NTT Advanced Technology Corporation, gave a lecture titled “WinActor Business71

Information

Table 1. List of Tsukuba Forum 2019 exhibits.
NTT Group companies
NIPPON TELEGRAPH
AND TELEPHONE EASTCORPORATIONNTT EAST-MINAMIKANTOCORPORATIONNTT EAST-KANSHINETSUCORPORATIONAIREC ENGINEERINGCORPORATIONNTT RENTAL ENGINEERING
CO., LTD.
Nippon Telematique Inc. (NTI)NIPPON TELEGRAPH
AND TELEPHONE WEST
CORPORATIONNTT Communications
Corporation
NTT PC Communications
Incorporated
NTT World Engineering Marine
Corporation
NTT COMWARECORPORATIONNTT Electronics Corporation
NTT Advanced Technology
Corporation
NTT-AT TECHNO
COMMUNICATIONSCORPORATIONNTT TechnoCross Corporation
NTT Infrastructure Network
Corporation
NIPPON CAR SOLUTIONS
CO., LTD.
Information &Telecommunications
Engineering Association ofJapan (ITEA)
EXEO TECH CORPORATIONKYOWA EXEO CORPORATION
Nippon COMSYS Corporation
MIRAIT Corporation
TOSYS CORPORATIONNDS Co., Ltd.
C-Cube Corporation Ltd.
Hokuriku Denwa Kouji Co., Ltd.
NIPPON DENTSU CO., LTD.
MIRAIT Technologies
Corporation
SOLCOM Co., Ltd.
Shikokutsuken Co., Ltd.
Seibu Electric Industry Co., Ltd.
SYSKEN Corporation
DAIWA DENSETSUCORPORATIONTTK Co., Ltd.
TSUKEN CORPORATION
Communication Line
Products Association of
Japan
AICHI CORPORATIONASABA MANUFACTURING
CO., LTD.
IWABUCHI CORPORATIONOCC Corporation
Okano Cable Co., Ltd.
KANDO Co. Ltd.
FUJIKURA HIGH OPT Co. LTD.
JFE Metal Products Corporation
JAPAN RECOM Ltd.
SHODEN SEIWA CO., LTD.
SWCC SHOWA CABLE
SYSTEMS CO., LTD.
Suzuki Giken Co., Ltd.
SUDA SEISAKUSHO Co., Ltd.

Overview.”
Mr. Kitamura first gave an overview of WinActor.
WinActor is a client PC (personal computer)-based
robot process automation (RPA) tool developed by
NTT research labs in 2010 with its unified management support system technology. It was commercialized by NTT Advanced Technology and released in
2014. As of the first half of 2019, over 4000 companies have adopted this software, giving it the largest
RPA tool market share in Japan. Over 700 companies
are currently sales partners of this software.
Next, Mr. Kitamura described WinActor’s threemajor features: simplicity, support, and scalability.
New functions to strengthen the product and promote
simplicity include a new service called Cast on Call,
which provides ready-made scenarios for task automation, contour matching, and enhanced virtualizaNTT Technical Review

Vol. 18 No. 4 Apr. 2020

Sumiden Opcom, Ltd.
Sumitomo Electric Industries,
Ltd.
Corning International K.K.
DYDEN CORPORATIONDAITO DENZAI CO., LTD.
TADANO LTD.
Tsushin Kogyo Electric Wire &Cable Co. Ltd.
TOTSU-SOKENCORPORATIONSEI Optifrontier Co., Ltd.
NISHI NIPPON ELECTRIC
WIRE & CABLE CO., LTD.
NIPPON CONCRETE
INDUSTRIES CO., LTD.
Nippon Tsushin Denzai Co., Ltd.
Fujikura Ltd.
Fujikura Dia Cable Ltd.
Furukawa Electric Co., Ltd.
MASARU INDUSTRIES, LTD.
DAINICHI CONCRETE
INDUSTRY CO., LTD
Milliken Japan G.K.
Japan Telecommunications
Equipment and Materials
Manufacturers Cooperative
Association (Zentsukyo)
Asakuraseisakusho Co, Ltd.
OTANI KOGYO CO., LTD.
Sankosha Corporation
SANWA DENKI KOGYO CO.,LTD.
SANRITZ ELECTRONICS CO.,LTD.
TAIEI Manufacturing Co., Ltd.
Takacom Corporation
TAKACHIHO SANGYO CO.,LTD.
Chuko Electric Co., Ltd.
TOMEITSUSHINKOGYO CO.,LTD.
NAGAMURA
MANUFACTURING CO., LTD.
NISSHIN ELECTRIC CO., LTD.
HACHIKO ELECTRIC CO., LTD.
MSK Technologies Co.,LtdWATANABE CO., LTD.
Other Corporations
Anritsu Corporation
NEC Corporation
NEC Magnus Communications,
Ltd.
NTEC
FXC Inc.
Oi Electric Co., Ltd.
OPT Gate Co., LTD.
SUNREC CO., LTD.
SHOSHIN Corporation
Seiko Solutions Inc.
HARADA CORPORATION
Hitachi, Ltd.
FUJITSU LIMITED
HellermannTyton Co., Ltd.
MAEDA ROAD
CONSTRUCTION Co., Ltd.
MARUBUN CORPORATIONMIKI Inc.
Mitsubishi Electric Corporation
Yokogawa Test & Measurement
Corporation / Yokogawa
Solution Service Corporation
RIKEN KEIKI Co., Ltd.

tion support. Version 7, slated for release in 2020, willfeature a refreshed user interface (UI) and multilingual support. Mr. Kitamura also discussed personnel
training to bolster support and gave examples of WinActor’s management functions and enhancements forachieving scalability. He argued that to further
strengthen collaboration with work applications for
digital transformation (DX), the key issues are how tomigrate WinActor to the cloud and implement onpremise and cloud collaboration and how to use artificial intelligence (AI) in areas where human judgment is required, which is not stereotypical, thus
considered an area RPA tools are poor at.
Finally, Mr. Kitamura stated that NTT Advanced
Technology is further pursuing customer’s DX byincreasing customer value when using WinActor
together with all NTT’s partners through the72

Information

Photo 1. Keynote speech delivered by Motoyuki Ii, senior
executive vice president and representative
member of the Board, NTT.

Photo 2. K eynote speech delivered by Naoki Shibutani,senior executive vice president and representative
director, NTT EAST.

Photo 3. W orkshop leaders (from left to right: Kazuo Kitamura, business unit manager, NTT Advanced Technology; Minoru
Tanaka, project manager, AS Labs; and Takeshi Onizawa, project manager, AS Labs ).

Technology Partner Program established in July
2019.
3.2 Workshop 2
Mr. Minoru Tanaka, executive research engineer
and supervisor of the Civil System Project, AS Labs,
gave a lecture titled “R&D Trends in Technologies
for Maintaining and Managing Telecommunication
Infrastructures.” For details, see the article in thisissue [3].

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

3.3 Workshop 3
Mr. Takeshi Onizawa, executive research engineer
and executive manager of the Wireless Entrance Systems Project, AS Labs, gave a lecture titled “Wireless
Systems Technologies for Present and Future Services.” For details, see the article in this issue [4].
4. Two-day events
4.1 30th Tsukuba Forum Exhibit
The evolution and the future of access network73

Information

Photo 4. 30th Tsukuba Forum Exhibit.

Photo 5. Panel discussion.

technologies were showcased. Changes through theeras and transformation of systems were exhibited.
Some visitors viewed the exhibit nostalgically, andmany said, “I could easily understand how thingschanged” (Photo 4).

5. Overview of exhibits

4.2 Panel discussion
Co-hosting organizations, NTT Group companies,
and the NTT research labs united to introduce efforts
and hold salon-style discussions on two themes:“Next-generation optical fiber cable technology” and“New wireless developments in the Reiwa era*.” Thepanelists introduced examples from different companies. Many attendees commented, “I learned a lot”
and “It was extremely interesting” after listening todiscussions about specific challenges for the futureand different companies’ views (Photo 5).
4.3 R adio equipment supporting the local community and disaster preparedness
A video presentation on wireless facilities that support safe living in remote islands and mountain areasand prevent the isolation of affected areas during
disasters was given.
4.4 Stamp rally
A digital stamp rally using smartphones was carriedout for the third time at Tsukuba Forum 2019 toenable visitors to navigate throughout the exhibition
hall of AS Labs. Those who gathered the sevenstamps in the venue were awarded an original utility
pole number tag. When the souvenir was handed tothe participants, they remarked, “I look forward to
this every year” and “I want to collect the utility pole
number tag every year.”
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

In addition to exhibits from AS Labs, exhibits on
the latest technologies of the co-hosting organizations and NTT Group companies were held (Photos
6 and 7).
5.1 AS Labs
The exhibition area was divided into three zones inwhich a wide range of AS Labs’ R&D results were
exhibited (Fig. 1). Recommended exhibits weremarked and presented to attendees in an easy-tounderstand manner (Photo 8).
(1) Future access network
Optical and wireless technologies that will makefuture access networks a reality were introduced.
Recommended exhibits included presentations ofanalog radio-over-fiber technology to accommodate
high-frequency multi-band radio systems, the direction of technological development to achieve futureaccess networks, protocol-free wavelength-management-control technology, and optical-fiber environment monitoring.
(2) Pioneering technologies
State-of-the-art technologies to develop futureaccess networks for a smart world were introduced. A
recommended exhibit showed the information andcommunication technology (ICT) transformation of aconduit management system.
(3) Supporting technologies
Cutting-edge technologies to support a safe andsecure society and current access networks were*

Reiwa is the name of the current Japanese imperial era, whichbegan on 1 May 2019.

74

Information

Photo 6. Main hall.

Photo 7. Outdoor exhibits.

Future access network
Introduces optical and wireless key technologies that will be responsible for futureaccess networks.

Pioneering technologies
Introduces state-of-the-art technologies that will pioneer future access networks forachieving a smart world.

Supporting technologies
Introduces cutting-edge technologies that support a safe and secure society and thecurrent access network.

Display of a model network
Introduces an overview of the access network technologies (those already deployed) ina physical sequence from an NTT building to customer’s premise.

Fig. 1. Overview of NTT exhibits.

introduced. Recommended exhibits included UI
extension technology to easily enable external collaboration, Internet of Things (IoT) wireless communication technology that extends the Wi-Fi standard(IEEE802.11ah), rule-learning-based failure location
estimation and response support AI, optimal control
technology that reflects human intentions, optimal
wiring route configuration technology to avoid cablecongestion, wiring technology with tolerance fordemand fluctuation and that does not require operation, automatic failure recovery technology with
auto-configuration and auto-wiring, multi-layer network autonomous control technology, automatedmanhole inspection technology using drones, technology for obtaining absolute coordinates of underground facilities, technology to visualize load andtechnology for understanding the relationship
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

between unbalanced loads and structural degradation,and technology for making reinforced-concrete manholes maintenance-free.
(4) Display of a model network
This exhibit visually introduced the overall pictureof access network technologies in a physical sequence
from an NTT facility building to the customer’shome.
5.2 I nformation & Telecommunications Engineering Association of Japan (ITEA)This exhibit presented ITEA’s efforts to develop
secure, safe, and reliable information communication
infrastructure facilities. These efforts include maintaining the technology and know-how that have beencultivated thus far; building, maintaining, andimproving the quality and efficiency of optical access75

Information

Photo 8. NTT exhibition zone.

Photo 9. Events of exhibiting companies.

networks; and promptly restoring facilities in theevent of a major disaster.

5.6 Events of exhibiting companies
In the AS Labs main hall and in the outdoor venue,
exhibiting companies gave demonstrations, whichdrew many visitors (Photo 9).

5.3 C
 ommunication Line Products Association ofJapan
The latest efforts and technologies of all the member companies were displayed. The technologies andproducts exhibited included optical and metal cables,
connectors, and related components for outdoor
facilities and technologies and products for datacenters and indoor facilities. Demonstrating safety considerations and diversity of needs, the offeringsemphasized workability and drew the interest of
many visitors.
5.4 J apan Telecommunications Equipment andMaterials Manufacturers Cooperative Association (Zentsukyo)
With the slogan “Contributing to the developmentof an IoT society with reliable technologies and theart of manufacturing (monozukuri),” exhibitors
belonging to Zentsukyo introduced their unitedefforts as an association to comprehend the expansionof the ICT market and environmental changes andrespond to customers’ demands with a sense ofurgency.
5.5 NTT GroupThrough their exhibits, NTT Group companies
demonstrated collaborations with business partners
as Your Value Partner through business activities. As
Your Value Partner, NTT seeks to achieve a smart
society through R&D and the use of ICT platforms.
The exhibits introduced the NTT Group’s latest technologies that contribute to solving social challenges.
NTT Technical Review

Vol. 18 No. 4 Apr. 2020

6. Conclusion
Tsukuba Forum 2019 was blessed with sunny
weather on both days. It was a success, drawing about
9400 attendees, including many international visitors. They expressed great interest in the presentations of exhibiting companies, including the latest
R&D and future trends of AS Labs. Visitor questionnaires were distributed, and the results indicated that
97% of customers achieved the purpose of their visit.
Tsukuba Forum 2019 was a rich event that allowed
NTT and participating organizations to share transformations in access networks through presentationsof short-term efforts to support current access networks and pioneering medium and long-term efforts
to create future access networks.
Acknowledgments
We thank the Information & Telecommunications
Engineering Association of Japan, the Communication Line Products Association of Japan, and theJapan Telecommunications Equipment and Materials
Manufacturers Cooperative Association (Zentsukyo)
for their support of Tsukuba Forum 2019.
References[1]

M. Ii, “Working toward Sharing Social Infrastructure,” NTT Technical Review, Vol. 18, No. 4, pp. 27–34, 2020.

76

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[2]

[3]

https://www.ntt-review.jp/archive/ntttechnical.php?contents=
ntr202004fa5.html
N. Shibutani, “Pioneering a Prosperous Future with Regional Innovations,” NTT Technical Review, Vol. 18, No. 4, pp. 35–42, 2020.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=
ntr202004fa6.html
M. Tanaka, “Technical Trends in Infrastructure Maintenance Management,” NTT Technical Review, Vol. 18, No. 4, pp. 43–48, 2020.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=
ntr202004fa7.html

Tomoyuki Nomura
Senior Research Engineer, Planning Section,
NTT Access Network Service Systems Laboratories.
He received a B.S. and M.E. from Waseda
University, Tokyo. From 1996 to 1998 he taught
access technology as a Japan Overseas Cooperation Volunteer in the Republic of Honduras. After
that, he worked mainly on network service system development at NTT WEST and NTT Network Service Systems Laboratories. He has beenwith NTT Access Network Service Systems
Laboratories since July 2017.

Yusuke Koshikiya
Senior Research Engineer, Planning Section,
NTT Access Network Service Systems Laboratories.
He received a B.E. and M.E. in mechanicalengineering and a Ph.D. in electrical engineeringfrom Waseda University, Tokyo, in 2001, 2003,
and 2015. In 2003, he joined NTT Access Network Service Systems Laboratories. He has been
engaged in research on optical fiber sensing andmaintenance technologies for optical fiber networks. He is a member of the Institute of Electronics, Information and Communication Engineers (IEICE). He was the recipient of the Institute of Electrical and Electronics Engineers(IEEE) Lasers and Electro-Optics Society Japan
Chapter Young Scientist Award and the Young
Researcher’s Award from IEICE in 2004 and2010, respectively.

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[4]

T. Onizawa, “Wireless Systems Technologies for Present and Future
Services,” NTT Technical Review, Vol. 18, No. 4, pp. 49–55, 2020.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=
ntr202004fa8.html

Trademark notes

All brand, product, and company/organization names that appear in thisarticle are trademarks or registered trademarks of their respective owners.

Motoharu Sasaki
Research Engineer, Planning Section, NTT
Access Network Service Systems Laboratories.
He received a B.E. in engineering and an M.E.
and Ph.D. in information science and electricalengineering from Kyushu University, Fukuoka,
in 2007, 2009, and 2015. In 2009, he joined NTT
Access Network Service Systems Laboratories.
He has been engaged in research on propagation
modeling for various wireless communication
systems; propagation modeling of interference
between mobile terminals for spectrum-sharing
wireless-access systems, propagation modelingin very high frequency (VHF) bands for emergency wireless systems, and propagation modeling in high frequency bands for fifth-generation
mobile wireless communication systems. He
received the Young Researcher’s Award and theBest Paper Award from IEICE in 2013 and 2014,
respectively. He received the Best Paper Award at
the International Symposium on Antennas andPropagation (ISAP) and the Young Engineer
Award from IEEE Antennas and Propagation
Society Japan Chapter in 2016. He also received
the Young Researcher Award and the Excellent
Paper Award from IEICE Technical Committee
on Antennas and Propagation in 2012 and 2018,
respectively. He is a member of IEEE.
Ikuko Takagi
Research Engineer, Planning Section, NTT
Access Network Service Systems Laboratories.
She received a B.E. in engineering and an M.E.
in information science and electrical engineeringfrom Tokyo University of Science, in 2010 and2012. In 2012, she joined NTT Access Network
Service Systems Laboratories. She has been
engaged in research on operational software forbusiness efficiency.

77External Awards
Distinguished Achievement and Contributions Award
Winner: Yutaka Miyamoto, NTT Network Innovation Laboratories
Date: June 6, 2019
Organization: The Institute of Electronics, Information and Communication Engineers (IEICE)
Dr. Miyamoto has long been engaged in research on the core technologies for high-speed, high-capacity optical transmission systems
used in optical networks and has made many achievements. In particular, he has made outstanding achievements in research on thecoherent, multicarrier, multilevel modulation/demodulation system.
Best Conversant Award
Winner: Keisuke Tsunoda, NTT Service Evolution Laboratories
Date: July 5, 2019
Organization: The Information Processing Society of Japan (IPSJ)
Committee of DICOMO 2019 symposium
He was selected because he asked interesting and thought-provoking questions at the DICOMO 2019 symposium.
Best Poster Award
Winner: Takashi Kurushima, Yoshiki Sakamoto, Kimi Ueda, Hirotake Ishii, Hiroshi Shimoda, Kyoto University; Rika Mochizuki,
Masahiro Watanabe, NTT Service Evolution Laboratories
Date: September 22, 2019
Organization: 3rd International Conference on Computer-Human
Interaction Research and Applications (CHIRA 2019)
For “A Study on Legibility with Pairwise Comparison in Simultaneous Multilingual Display on Digital Signage.”
Published as: T. Kurushima, Y. Sakamoto, K. Ueda, H. Ishii, H.
Shimoda, R. Mochizuki, and M. Watanabe, “A Study on Legibility
with Pairwise Comparison in Simultaneous Multilingual Display on

Digital Signage,” Proc. of CHIRA 2019, Vienna, Austria, Sept. 2019.
Award for Encouragement of Research in the 29th Annual
Meeting of MRS-J Symposium L
Winner: Riku Takahashi, NTT Basic Research Laboratories
Date: November 29, 2019
Organization: The Materials Research Society of Japan (MRS-J)
For “Creation of Tough Hydrogel Architectures Towards Obtaining Hydrogel Fluidic Devices.”
Published as: R. Takahashi, “Creation of Tough Hydrogel Architectures Towards Obtaining Hydrogel Fluidic Devices,” 29th Annual
Meeting of MRS-J, Yokohama, Japan, Nov. 2019.
The 2nd Hyogo-Kansai Caterpillar STEM award, Outstanding Achievement Award
Winner: Keiko Takase, NTT Basic Research Laboratories
Date: February 11, 2020
Organization: Caterpillar JapanFor her research on electrical control of spin-orbit interaction using
semiconductor nanowire.
IPSJ Yamashita SIG Research Award
Winner: Yusuke Ichikawa, NTT Service Evolution Laboratories
Date: March 6, 2020
Organization: IPSJ
For “Evaluation of Dynamic Guide Signs Control Pedestrians in
Public Facilities.”
Published as: Y. Ichikawa, A. Hayashi, Y. Mihara, K. Shimizu, and
H. Tezuka, “Evaluation of Dynamic Guide Signs Control Pedestriansin Public Facilities,” IPSJ SIG Tech. Report, Vol. 2019-CDS-24, No.
31, 2019.

Papers Published in Technical Journals andConference Proceedings
Topological Stack-queue Mixed Layouts of Graphs
M. Miyauchi
IEICE Transactions on Fundamentals of Electronics, Vol. E103-A,
No. 2, pp. 510–522, February 2020.
One goal in stack-queue mixed layouts of a graph subdivision is toobtain a layout with a minimum number of subdivision vertices peredge when the number of stacks and queues are given. Dujmovi andWood showed that for every integer s, q > 0, every graph G has an

NTT Technical Review

Vol. 18 No. 4 Apr. 2020s-stack q-queue subdivision layout with 4 log(s+q)q sn(G) (resp. 2 +4 log(s+q)q qn(G) ) division vertices per edge, where sn(G) (resp.
qn(G)) is the stack number (resp. queue number) of G. This paper
improves upon these results by showing that for every integer s, q >0, every graph G has an s-stack q-queue subdivision layout with at
most 2 logs+q–1 sn(G) (resp. at most 2 log+s+q–1 qn(G) +4) divisionvertices per edge. That is, this paper improves upon the previous
results for graphs with larger stack number sn(G) or queue number78

Papers Published in Technical Journals and Conference Proceedings

qn(G) than given integers s and q. Also, the larger the given integer s
is, the more the previous results are improved.

A Method to Determine If a Test Case Is Necessary Using
Support Vector Machine
S. Sunaga, K. Kikuma, K. Jimbo, K. Satoh, and K. Ueda
Proc. of the 2nd International Conference on Artificial Intelligencein Information and Communication (ICAIIC 2020), pp. 448–453,
Fukuoka, Japan, February 2020.
Communication software used for the Next Generation Network(NGN) is required to be highly reliable, so it incorporates manymethods to improve quality and prevent service interruptions during

NTT Technical Review

Vol. 18 No. 4 Apr. 2020

operation of public networks. However, the accumulation of quality
improvement methods has resulted in problems with longer development times and increasing costs. The authors are working to solve
such problems by automating development processes. In this paper,
we propose a method of determining if a test case is necessary using
a support vector machine. We vectorize know-how regarding thecreation of verification test cases from experts who understand therequirement specifications. The support vector machine learns thevector as the training data. Then this is used to automatically determine if a test case is necessary. We evaluated the effectiveness of themethod in automatically determining if a test case of particularrequirements is necessary through practical experiments.

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