Development of Insulation Diagnostic Techniques forDistribution Line Using FDTD Method
Partial Discharge
Transformer

Ez (V/m)

Antenna
s
1.5
1
0.5
0
-0.5
-1
-1.5

Direction of Arrival
Estimationᶁᶐᵿᶁᶉᴾ
0

20

40

60
Time (ns)

80

100

120

Electromagnetic Waves Emitted from a Partial Discharge Source,which is a Symptom of Deterioration of Insulating Materials.

Detection of Abnormal Vibration Using Wavelet Transform䣃䣥䣥䣧䣴䣧䣮䣣䣶䣫䣱䣰䢢䢪䣰䣱䣴䣯䣣䣮䣫䣼䣧䣦䢫

䢴䢲
䢳䢲
䢲
䢯䢳䢲
䢯䢴䢲

䢲

䢲䢰䢲䢲䢷

䢲䢰䢲䢳

䢲䢰䢲䢳䢷

䢲䢰䢲䢴
䢲䢰䢲䢴䢷
䣖䣫䣯䣧䢢䣝䣵䣟

䢲䢰䢲䢵

䢲䢰䢲䢴
䢲䢰䢲䢴䢷
䣖䣫䣯䣧䢢䣝䣵䣟

䢲䢰䢲䢵

䢲䢰䢲䢵䢷

䢲䢰䢲䢶

Keywords䠖Radio Sensing and Signal Processing
E-mail: kawada@ee.tokushima-u.ac.jp
Tel. +81-88-656-7460
Fax: +81-88-656-7460䢴䢶䢲䢲䢲䣈䣴䣧䣳䣷䣧䣰䣥䣻䢢䣝䣊䣼䣟

䢳䢴䢲䢲䢲
䢸䢲䢲䢲
䢵䢲䢲䢲
䢳䢷䢲䢲
䢹䢷䢲
䢵䢹䢷

䢲

䢲䢰䢲䢲䢷

䢲䢰䢲䢳

䢲䢰䢲䢳䢷

Content:
1. Subject
Can faults due to deterioration over time or unexpectedfaults occurring in power equipment be detected
beforehand ?
2. Research Contents
How to detect a symptom of faults ?
(1) Radio Sensing, to locate the positions of deteriorationof insulating materials(2) Signal Processing, to locate abnormal positions inturbines, generators, and pumps
3. Record of Joint Research(1) Chubu Electric Power Co. Inc. and Mitsubishi Heavy
Industries Ltd. for diagnosing turbine generators(2) Chubu Electric Power Co. Inc. and Hitachi Ltd. fordiagnosing pumps(3) Railway Technical Research Institute for diagnosing
ground coils of superconducting Maglev

䢲䢰䢲䢵䢷

䢲䢰䢲䢶

Time-Frequency Visualization of Abnormal
Vibration

HP: http://pub2.db.tokushima-u.ac.jp/ERD/
person/25080/profile-ja.ht䡒mlᶁᶐᵿᵿᶁᶉ
ᶁᶐᵿᶁᶉᴾ

Fig.1 Feedback control of a time delay system

Content:
㻌 Systems with time delay belong to a class of infinite
dimensional systems. To construct a linear quadratic
regulator of such a system, generally a solution of an
infinite dimensional Riccati equation is required to
calculate the feedback gain and a real-time integral
operation is included in the feedback law.
To stabilize such systems, we propose a method toconstruct an inverse linear quadratic regulator. The
feedback gain can be calculated from a solution of afinite dimensional Riccati equation or a finite dimensional
linear matrix inequality, and the feedback law is so-called
the memoryless feedback which doesn’t include a realtime integral operation as shown in Fig. 1. The resulting
closed loop system can be shown to be stable (compare
Fig. 2 and Fig. 3 for example), and to be a linear
quadratic regulator for some quadratic cost functional.
Moreover, it is assured to have a good robustness
property against a class of static nonlinear perturbations
or dynamic linear perturbations in the input channel aswell as a linear quadratic regulator for systems without
time delay.
Keywords䠖time delay, LQ regulator, robust stability
E-mail: kubo@ee.tokushima-u.ac.jp
Tel. +81-88-656-7466
Fax: +81-88-656-7466

Fig.2 Open loop system

Fig.3 Closed loop system

Content:
㻌 Research of heuristic algorithm
㻌 for optimization problems in LSI layout design㻌㻌 For example,
㻌 䞉 Obstacle avoiding rectilinear steiner tree (Fig.1)
㻌 䞉 Voltage assignment in floorplan (Fig.2)
㻌 䞉 3D-IC floorplanning with TSV co-placementᶁᶐᵿᶁᶉᴾ

Fig.1 Obstacle avoiding
rectilinear steiner tree

Keywords䠖Heuristic Algorithm, Optimization Problem,
LSI Design
E-mail: simamoto@ee.tokushima-u.ac.jp
Tel. +81-88-656-7483
Fax: +81-88-656-7471
Fig.2 Voltage assignment in floorplan

Voltage [kV]

Power

150

10GW
X
10ns

100W X 1s

100
50
0
-10

Time

Fig.1 What is pulsed power

0

10Time [ns]20

Fig.2 Ns voltage pulseᶁᶐᵿᶁᶉᴾ㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌㻌Fig.4 Steamer
discharges
Stainless Steel Wires

Gas
Inlet

Glass
Pipe

Fig.3 Pulsed power application㻌 㻌 㻌 㻌 㻌 㻌 㻌 㻌 㻌 㻌 㻌 㻌 Fig. 5 Water
Treatment

Gas
OutletFlow ofWater㻌 㻌 㻌 㻌 㻌 㻌 㻌 㻌 㻌 Fig.6 Cancer therapy

Pump
Valve

Cu Tape

Content:
Pulse power is the technology of utilizing high power
pulses obtained by compressing energy. We focus on green
technologies and applications in bioengineering.
Nanosecond pulsed power has been applied on environmental protection technology. It can efficiently produce
streamer discharges as which were suitable for dischargechemical processing. There are the high-efficient ozone
production, the exhaust gas treatment of nitrogen oxide(NOx), and the water treatment for persistent substances.
Applications in bioengineering utilize the influence ofelectric pulses and discharges on biological body. The
influences can be controlled by the pulse width (spectrum),various applications can be expected. There are theproduction technology of micro algae biomass fuel andgrowth control of plants. We are developing the new cancer
therapy and the control method of endoplasmic-reticulumstress response aiming at prevention of disease, using
nanosecond pulsed powers.
Keywords䠖pulsed power, bioelectrics, pulse electric fieldE-mail: simon@tokushima-u.ac.jp>
Tel. +81-88-656-7463
Fax: +81-88-656-7463

㻌
W
D
M

W
D
M

Optical Amplifiers(Repeaters)
Optical transmission distance

OpticalTransmitters

OpticalReceivers

㻿㼕㼓㼚㼍㼘㻌
㼘㼕㼓㼔㼠㻌

㻱㼘㼑㼏㼠㼞㼕㼏㼍㼘㻌㼒㼕㼑㼘㼐㻌㻭㼙㼜㻚㻌Fig.1 Configuration of backbone optical fiber transmission system

S/2ᶁᶐᵿᶁᶉᴾ㼐㼑㻙㼍㼙㼜㼘㼕㼒㼕㼏㼍㼠㼕㼛㼚㻌㻽㼡㼍㼐㼞㼍㼠㼡㼞㼑㻌㻵㼚㻙㼜㼔㼍㼟㼑㻌㻼㼡㼙㼜㻌㼘㼕㼓㼔㼠㻌㼍㼙㼜㼘㼕㼒㼕㼏㼍㼠㼕㼛㼚㻌㻰㼕㼟㼠㼍㼚㼏㼑㻌(a)㻌 Fundamental㻌 operation of PSAᶁᶐᵿᶁᶉᴾ

Pump Laser
Input

Optical㻌 PLL* (*PLL : Phaselock loop)

Optical Hybrid
Photo Diode
Optical Parametric Medium

Output(b)㻌 Basic configuration of PSA
Fig. 2 Optical parametric phase sensitive amplifier (PSA)

Content:㻌 The performance of communication㻌 network㻌 has been㻌drastically 㻌 enhanced 㻌 by 㻌 adopting 㻌 fiber-optic㻌
transmission㻌 technologies㻌 into the backbone networks
and access networks. Recently, the demand forcommunication capacity is increasing even more,because of popularization of cloud type-application andtransportation of ultra-broadband contents such as highdefinition moving pictures. The purpose of our laboratoryis bringing a significant progress of communication
network by introduce novel functionality into the opticalcommunication network.
㻌 One of our topics of research is expanding opticaltransmission distance - capacity in backbone networks(Fig.1) by introducing phase-sensitive optical amplifiers(PSA) (Fig.2) as optical amplifier repeaters. PSAs
amplify in-phase and de-amplify quadrature component
with reference to phase-locked pump light in parametricamplifiers. Significant extension of optical transmission
distance is expected by numerical simulation ontransmission system. We have also successfully
demonstrated the principles of PSA functionality.
Keywords䠖optical communication,
optical fiber, optical amplifier
optical signal processing
E-mail: takada@ee.tokushima-u.ac.jp
Tel. +81-88-656-7465

nbar

s

1
3HULRGȁ:DYHOHQJWKȜ(b) Periodic distribution ofrefractive index for light(a) Schematic diagramᶁᶐᵿᶁᶉᴾ grating structure
Fig.1 Sub-wavelengthᶁᶐᵿᶁᶉᴾ

Fig.2 Electrical field distribution Fig.3 Fabricated sub-wavelengthgg on UV-LED surface
grating
for TM light by FDTD theory
LQFDVHRIȜȁ Content:
㻌 Highly polarized UV emission devices were expected
to develop the applications, such as high resolution
imaging, high sensitive sensors, etc. The compact
polarization control device with high transmittance isrequired in order to develop integrated device for theseapplications.
One of the candidates to overcome the issue is thedevice using high contrast dielectric subwavelength
grating (SWG) structure. In SWG, the pitch of the grating
is shorter than the wavelength of incident light. The Blochlike eigen-modes within SWG region resulting from thespatial periodicity of refractive index distribution interacts
with incident light. As a result, the desirable opticalcharacteristics such as broadband high reflectivity andpolarization sensitivity are obtained with optimal
structures.
We have investigated the polarization characteristics of
AlGaN-based UV-LED with SWG fabricated on the top of
LED surface, and demonstrated the feasibility of highpolarized UV-LED grown on c-plane sapphire.
Keywords 䠖 photonic device, sub-wavelength grating,polarization control, nano device
E-mail: naoi@ee.tokushima-u.ac.jp
Tel. +81-88-656-7447
Fax: +81-88-656-7447

Fig.4 Emission spectrafrom UV-LED

Fig.5 Polarization ratio from UV-LED
with sub-wavelength grating㻴㻼㻦㼔㼠㼠㼜㻦㻛㻛㼏㼙㼟㻙㼘㼐㼍㼜㻚㼐㼎㻚㼠㼛㼗㼡㼟㼔㼕㼙㼍㻙㼡㻚㼍㼏㻚㼖㼜㻌㻌㻌㻌㻌㻌㻌㻛㻰㻭㼂㻛㼜㼑㼞㼟㼛㼚㻛㻿㻝㻜㻣㻜㻟㻛㼃㻱㻮㻛㼕㼚㼐㼑㼤㻚㼔㼠㼙㼘㻌Fig. 1: Logistic map,
Fig. 2: One-parameterᶁᶐᵿᶁᶉᴾ
one of the most famousbifurcation diagram of the
one-dimensional map
Logistic map.
generating chaos.

Fig. 3: Four autonomouschaotic circuits coupledby one resistor.

Fig. 4: Four-phasequasi-synchronizationof chaos observed fromthe circuits in Fig. 3.

Content:
1. Chaos Cryptosystems
Sensitive dependence of chaos on initial conditions
and parameters is exploited for various security
issues.
2. Chaos Communication Systems
Continuity of chaotic sequences generated from an
identical chaotic map is exploited to recover data
correctly.
3. Complex Networks
Various synchronization phenomena in coupledchaotic circuits are good models of various complex
networks.
4. Nonlinear Time Series Analysis
Chaos analysis is utilized to predict a trend of
nonlinear time series or to diagnose medical signals.
5. Data Mining
Self-organizing feature of artificial neural networks is
exploited to carry out clustering of various data.

Keywords䠖 chaos, chaos cryptosystems,
chaos communication systems, complex
systems, nonlinear time series analysis
E-mail: nishio@ee.tokushima-u.ac.jp>
Tel. +81-88-656-7470
Fax: +81-88-656-7471
HP : http://nlab.ee.tokushima-u.ac.jp/nishio.htm

Topics
1. Phasor measurements at demand sides and its applications
Developing an online monitoring of power system by multiple phasor
measurement units with monitoring voltages at the outlets on the
wall.

㻌㻌

2.

Management of distribution network with high penetration ofphotovoltaic generation units
Investigating reasonable voltage regulation on high and low voltage
distribution lines by cooperation of photovoltaic generation units andother apparatus.

3.

Advanced power conversion to integrate multiple dc energy sources
Integrating multiple dc voltage terminals to connect solar cells,
batteries and loads easily, based on multilevel converter topology
with flying capacitors.

4.

Series-connected dc-dc converter for multi-end dc powertransmission
Developing a high frequency dc-dc power converter in series with a dc
power transmission or distribution line to provide multi -ends.

5.

Power modulations of distributed energy resources for frequency
control
Developing a voltage phasor modulation of grid-connected converters
to regulate the system frequency as much as possible.

ἅὅἅὅἑἁἚɧᑣᴾὅἑἁἚɧᑣ

Fig. 1 My major researches.

Keywords: Smart Grid, Reliability, Stability,
Power Quality
Field: Power system and power electronics
E-mail: hojo @ ee.tokushima-u.ac.jp
Fig. 2 Grid monitoring.

Fig. 3 Dc sources integration.

Tel/Fax. 088-656-7452

Wind Turbine

Powercrack
assist suit Electric wheelchair

Multi-legged robot

Pesticide spraying robot

Electric Vehicle

Environmental monitoring

Content:
In recent years, demands for higher performance andadded value in industrial and life support equipment thatis designed to coexist with humans has been growing. In
order to satisfy these demands, we are conducting
research on the application of intelligent information
processing technology based on a bio-inspired approach.
The main research themes are as follows, and we arepromoting the realization of the elemental technologies
obtained in the research process through collaboration
research.
 Prediction of wind and solar power output based on
weather prediction models
 Control of automatic driving systems and cooperative
control of swarm mobile robots
 Motion control for legged robots and robot
manipulators
 Safe driving support system for electric wheelchairs
 Development of various agricultural support robots
Keywords：intelligent control, robot, wind energy andphotovoltaic power generation,
rehabilitation system
E-mail: yasuno.takashi@tokushima-u.ac.jp
顔写真
（省略可）
Tel. +81-88-656-7458
Fax: +81-88-656-7458
HP : https://www-sky.ee.tokushima-u.ac.jp

Content:

１ Introduction
Recently, structural and functional brain network havebeen made clear (Fig. 1). And, several research group havereported that the synaptic connection has heavy taildistribution as shown in Fig. 2. In this project, we investigate
synchronization of brain network model of macaque visualcortex with heavy tail coupling distribution.

２ Proposed system and results
Fig. 1Structural and functional brain networks

Figure 4 shows brain network model of macaque visualcortex. the node of network model is expressed by van der
Pol oscillator (Fig. 3). Figure 4 shows the simulation resultsof global synchronization. The network with heavy taildistribution synchronized to avoid global synchronization.

３ Future works
Fig. 2 Heavy tail distribution

Fig. 3 van der Pol oscillator

Investigation of more large brain network and make clear
the relationship between synchronization and high-functionof brain are our future works.
Keywords：coupled oscillators, synchronization,clustering
E-mail: uwate@ee.tokushima-u.ac.jp
Tel. 088-656-7662
Fax: 088-656-7471

Fig. 4 Brain network modelof macaque visual cortex

Fig. 5 Global synchronization

HP : http://nlab.ee.tokushima-u.ac.jp/uwate.htm

crack

Fig.1 A sample of snoring sound recordings

Content:
There are a lot of patients who suffer from chronic disease(e.g. obstructive sleep apnea and a bowel disease etc.).
Recently the prevalence of these diseases is likely to be
increasing in many countries. Polysomnography (PSG) andendoscopic test have been used for the diagnosis. Howeverthese tests are inconvenience and expensive. Our researchgroup hypothesizes that the information on these diseases
should be embedded in biological sounds (e.g. snoring andbowel sounds) obtained from the patients. Biological sounds
can be simply acquired via non-contact and/or non-invasive
measurements. The target of our study is to develop the
automated diagnosis system based on the analysis of
biological sounds. We are currently in the process ofdeveloping new sophisticated techniques for future medical
applications. Biological sound-based techniques can be
expected to provide an attractive alternative to theconventional test for chronic disease.

Keywords： Biomedical signal processing and bio-medical
instrumentation
E-mail: emoto@ee.tokushima-u.ac.jp
Tel. +81-88-656-7476
Fig.2 A sample of bowel sound recordings

Epitaxial graphene devices

コンタクト不良

Protein & amino acid adsorption
PBS
100 pM500
1 nM
5Drain current (µA)

28
24
20
-0.5

-0.4

-0.3

-0.2

Solution-gate voltage (V vs Ag/AgCl)

Net voltage change at KD (V)

0.15

0.05
0.00

CHT

-0.05
-0.10
-0.15

ILY
BSA

5

Hb

6

7

CytC

8

9

Isoelectric point (pH)

10

0.12

CHT

pH 6.8 (+)
pH 9.0 (-)
Fit

0.09
0.06
0.03
0.00
10-1

100

101

102

103

CHT concentration (pM)

104

Keywords：graphene, device, biosensor
E-mail: ohno@ee.tokushima-u.ac.jp
Tel. +81-88-656-7439
Fax: +81-88-656-7439
HP : http://graphene2.ee.tokushima-u.ac.jp/

Positively charged
Negatively charged

0.10

0.15

Net voltage change (V)CHT, pH 6.8

32 Positively charged

Since the electrical characteristics of graphene fieldeffect transistors (FETs) are very sensitive for theirenvironmental condition, the graphene FETs have highpotential for chemical and biological sensors. In ourlaboratory, various sensors based on graphene FETs areinvestigated. The graphene FETs can be operated in thebuffer solution by top-gated operation from a referenceelectrode without any passivation film owing to their large
potential window.
The most original point of our work is to use the epitaxial
graphene film on a SiC substrate, which has single
crystal with large area. The epitaxial graphene FET isexpected to obtain the inherent characteristics ofgraphene owing to the free of defects and dislocation.
Now we have investigated protein and amino acidadsorption characteristics. They showed always electron
doping to graphene, indicating the cleanness surface ofthe epitaxial graphene film. We now try to realize thespecific target detection beyond the Debye screening
length owing to the small quantum capacitance.

11⁤⁗⁥⁡⁞⁧⁦⁛⁡⁠‒⁗⁠⁚⁓⁠⁕⁗ ⁗⁠⁦‒⁞⁓⁫⁗⁤‒⁔⁓⁥⁗‒⁞⁓⁫⁗⁤‒⁦⁛ ⁗‒‸⁛⁙†‣‬‒›†․ …‡⁅⁈‵‒⁛⁠⁦⁗⁤‒⁞⁓⁫⁗⁤‒⁢⁤⁗⁖⁛⁕⁦⁛⁡⁠‒‒⁗⁠⁕⁡⁖⁛⁠⁙‒⁘⁡⁤‒⁗⁠⁚⁓⁠⁕⁗ ⁗⁠⁦‒⁞⁓⁫⁗⁤‒⁢⁤⁗‟⁢⁤⁡⁕⁗⁥⁥⁛⁠⁙‒⁘⁡⁤‒⁗⁠⁚⁓⁠⁕⁗ ⁗⁠⁦‒⁞⁓⁫⁗⁤‒⁢⁤⁗‟⁢⁤⁡⁕⁗⁥⁥⁛⁠⁙‒⁘⁡⁤‒⁔⁓⁥⁗‒⁞⁓⁫⁗⁤‒⁗⁠⁕⁡⁖⁛⁠⁙‒⁘⁡⁤‒⁔⁓⁥⁗‒⁞⁓⁫⁗⁤‒
ᶁᶐᵿᶁᶉᴾ⁀⁡⁨⁗⁞‒⁢⁤⁗⁖⁛⁕⁦⁛⁡⁠‒ ⁗⁦⁚⁡⁖⁥‒⁆⁤⁓⁖⁛⁦⁛⁡⁠⁓⁞‒⁢⁤⁗⁖⁛⁕⁦⁛⁡⁠‒⁗⁦⁚⁡⁖⁥≋›†․ …‡⁅⁈‵≌‒‸⁛⁙†․‬‒⁆⁚⁗‒⁢⁤⁡⁢⁡⁥⁗⁖‒⁕⁡⁖⁛⁠⁙‒⁥⁦⁤⁧⁕⁦⁧⁤⁗‒

With the widely spread of video applications, novel coding
algorithms which can answer many kinds of emerging
demands are highly required. Our research group is devoting
to propose good ideas concerning the following themes.
1. Improvements of the algorithms of HEVC and its low
complexity and low power VLSI architecture for the next
generation applications which are over 4K resolutions. The
algorithms and architectures are concerning the intra
coding, motion estimation, and deblocking filter.
2. Scalable video coding algorithms which are suitable forhigh resolution applications. We will make full use of thehigh correlations between base layer and enhancement
layer to propose new algorithms to improve the coding
efficiency.
3. Highly parallel processing video coding algorithms on
many core platforms. Most of traditional coding algorithms
utilize the coding parameters of adjacent blocks to
improve coding efficiency. However, this coding structure
has essential demerit for parallel processing. As shown in
Fig.2, our motivation is to find new coding structure which
can achieve higher parallel coding performance.

Keywords 䠖 H.265/HEVC, Scalable Video coding(SVC),
Parallel Video Coding㻱㻙㼙㼍㼕㼘㻦㻌㼠㼕㼍㼚㼟㼛㼚㼓㻬㼑㼑㻚㼠㼛㼗㼡㼟㼔㼕㼙㼍㻙㼡㻚㼍㼏㻚㼖㼜㻌㼀㼑㼘㻚㻌㻜㻤㻤㻙㻢㻡㻢㻙㻣㻠㻤㻠㻌㻲㼍㼤㻦㻌㻜㻤㻤㻙㻢㻡㻢㻙㻣㻠㻣㻝㻌㻌(b) Discharge plasmaἅὅἑἁἚɧᑣᴾ

(a) Configuration(c) Application to ozone generator

Fig. 1 Compact plasma reactor using piezoelectric device and its
application
Ozonizer

Content:㻌 㻌 Discharge plasma reactors consisting of a massive highvoltage generator and discharge electrodes are more likely to
become large-scale system. We have proposed and studied
various types of compact plasma reactors using piezoelectric
devices. Piezoelectric transformers (PTs) that act as compact
high-voltage generator have been widely embedded in abacklight invertor for LCDs. Our proposed plasma reactors
feature compact configurations because the devices serve as
both high-voltage source and discharge electrode. Nonthermal plasmas, such as corona discharge, glow discharge
and dielectric barrier discharge (Fig. 1(a)(b)) can be produced
using the plasma reactors. Several applications of the plasma
reactors to ozone generators (Fig. 1(c)) andvacuumultraviolet light source have been demonstrated.
We have also promoted actively other research ingeneration, diagnosis and applications of non-thermal
atmospheric pressure plasma, including in-situ measurementof ozone density inside DBD ozone generator (Fig. 2) andsusurrounding
gas-fed (SGF) plasma jet (Fig. 3).

DPSS laser(a) He/Air
Photodetector(b) He/O2
Fig. 2 In-situ O3 measurement bylaser optical absorption

FFig.
ig 3 SGF Plasma jet

Keywords䠖Dielectric barrier discharge,
Kozone, plasma jet
E-mail: teranishi@ee.tokushima-u.ac.jp
ETel.
T
e +81-88-656-7454
Fax: +81-88-656-7454
F
http://pub2.db.tokushimahtu.
u.ac.jp/ERD/person/155803/profile-ja.html

㻌㻌㻌㻌㻌 㻌The㻌 㻌 material modification due to the femtosecond laser
irradiation on wide bandgap semiconductors has been studied.
The spontaneous formation of nano-periodic structures andthe amorphization due rapid heating and cooling process
occurs after femtosecond laser irradiation. Wide bandgap
semiconductors can be processed through the multi-photon
process because of their transparency to femtosecond laser

Fig.1 : Raman spectra with femtosecond laser irradiation on theinterface between nickel and silicon carbide

beam.
Fig. 1 shows Raman spectra after the femtosecond laser
irradiation on the interface between silicon carbide and nickel.
D and G bands due to carbon was observed, and thisindicates that the carbon atom reached the nickel surface.
㻌 Fig. 2 shows the schematic of electrical conduction control
by fs laser modification. The femtosecond laser beam isirradiated between two metal contacts on semiconductor. With
increasing

theirradiation

fluence,

the

local

electricalconductivity abruptly decreased at the threshold fluence.

Fig.2 : Electrical conduction control by fs laser modification

Keywords䠖femtosecond laser, ablation
E-mail: tomita@tokushima-u.ac.jp
Tel. +81-88-656-7445
Fax: +81-88-656-7445
HP : http://pub2.db.tokushima-u.ac.jp/
ERD/person/ 82121/profile-en.html

30

45

60

2θ[deg.]Fig.1 XRD patternof BaSi2 thin film

Intensity[arb.unit]

411

222

111
201
211

400

200

600

301

Intensity[arb.unit]
15

200

Eg+Fg
Eg Fg

Ag

Fg

400
600
Raman shift[cm -1]

Fig.2 Raman spectrumof BaSi2 thin film

We are studying on crystal growth and device
applications of two kinds of semiconductors.
1. BaSi2 has suitable properties for thin film solar cells,such as a bandgap, high absorption coefficients, andlong minority carrier diffusion length. We grow BaSi2 thinfilms on Si(100) substrates by conventional vacuum
evaporation. Obtained films are a-plane oriented (Fig.1)
and of high quality estimated by Raman scattering
spectroscopy as shown in Fig.2. We are currently
investigating the crystal quality, electrical and opticalproperties in detail for solar cell applications.
2. Ga2O3 is a widegap semiconductor and is expected asa material for high-power devices and various kinds ofsensors. Among some polymorphs of Ga2O3 , we growthin films and nanowires of most thermally stable βphase by a direct synthesis method, which utilizes direct
reaction of Ga and O2 gas. Fig.3 shows a surface SEM
image of a β-Ga2O3 thin film. The film has the stepterrace structure on the surface and is high quality withenough thickness. β-Ga2O3 nanowires with a diameter ofabout 100nm and a length of 10µm or longer can begrown on c-plane sapphire and glass substrates asshown in Fg.4.

1μm

Fig.3 Surface SEM imageof β-Ga2O3 thin film

Fig.4 SEM image of
β-Ga2O3 nanowires

Keywords：BaSi2, Ga2O3, Nanowire
E-mail: knishino@tokushima-u.ac.jp
Tel. +81-88-656-7464
Fax: +81-88-656-7464

ᶁ ᶐ ᵿ ᶁᶉᶁᶐᵿᶁᶉᴾ

Fig.1 overview of design for testability

Fig.2 Boundary scanwith TDC

Fig.3 layout ofan experimental chipContent:
㻌 In recent highly integrated VLSIs, cost of testing is amajor problem. To alleviate the difficulty in testing, designfor testability techniques are widely used. In our researchlab, we develop methods for reducing test cost such as
test data volume, test application time, area overhead oftest circuit, and for improving test quality especially indelay testing. One of the techniques is design for
testability method for small delay faults using time-todigital converter embedded in boundary scan called
TDCBS, shown in the figures. The boundary scan cells
are modified to be able to form a time-to-digital converter
that is utilized for detecting delay. Using this architecture,defects like opens and shorts can be detected as extra
delay caused by such defects even if the delay is small
and cannot be detected by conventional logic test. The
feasibility of the proposed methods is estimated by both
simulation and experiments of fabricated chips.
Keywords䠖design for testability, VLSI testing,delay faults, test cost reduction
E-mail: h.yotsuyanagi@tokushima-u.ac.jp
Tel. +81-88-656-9183
Fax: +81-88-656-9183

Fig 1. Prototype of a measurement device for bloodflow velocity(BFV) and typical waveform of BFV in the
carotid arteryᶁ ᶐ ᵿ ᶁᶉᶁᶐᵿᶁᶉᴾFig 2. Change of BFV waveforms with age and exercise

Content:
㻌 According to the vital statistics from Ministry of Health,Labour and Welfare, 33% of Japanese are died bydiseases related to the circulatory system. It is wellknown that diet modification and an appropriate exercise
are effective to prevent these diseases. If we have aportable device which can evaluate the circulatory
system and exercise habit, it is expected to suppress
these diseases and medical care costs.
We have developed a portable measurement device(Fig. 1) for blood flow velocity (BFV) and investigated therelationship to various conditions for hundreds ofsubjects. As results of them, BFV waveforms show
remarkable trends corresponding to aging and exercise
habit as shown in Fig. 2. These trends may reflect extent
of atherosclerosis. We confirmed that they are caused bycompliance of the arteries by use of the multi-branchedarterial segment as shown in Fig.3.

Keywords 䠖 Ultrasound doppler, atherosclerosis, bloodflow velocity
E-mail: makutaga@ee.tokushima-u.ac.jp
Tel. +81-88-656-7477
Fax: +81-88-656-7477
Fig 3. Change of BFV waveforms for different
compliance of the arteries (computer simulation)

<図表>Photocatalytic Thin Film
New energy
production

Environmental
conservation
light

crack

human

earth
TiO2 thin film

Semiconductor Plasma Electronics

X-ray intensity (Arb. unit)

PVD sputtering

DBD plasmas

Anatase (101)

20

30

40
2θ (deg.)

50

Content:
Photocatalyst has been attracting much attention as amaterial for environmental conservation and new energy
production. The advantage is that the photocatalytic activity is
activated semipermanently while the surface is irradiated withlight. TiO2 is a leading candidate as the photocatalyst. This
reason is that the photocatalytic activity is activated easily
under irradiation with near UV-visible light and that TiO2 ishardly dissolved by its own photocatalytic activity. Since TiO2
is an inorganic compound, TiO2 is harmless for human andearth, and is stable in aqueous media and reactive gas. The
thin films, rather than the powders, are required from theviewpoint of the practical application such as large area
coating. The photocatalytic activity induced by use of the thinfilms, however, is less enhanced than that induced by use of
the powders.
We have been studying TiO2 thin films with excellent
photocatalytic activity by using a magnetron facing target
sputtering deposition device developed by our group. The
characteristic of the deposition device is that the anatase thinfilms is fabricated without heating the substrate andperforming the post-annealing. We have also been studying
the anatase films treated by using an atmospheric pressureplasma device developed by our group, in order to further
enhance the original photocatalytic activity. The characteristicof the treatment device is that the surface treatment isperformed easily in the absence of expensive vacuum pumps.

Keywords： Photocatalyst, Wide band-gap semiconductor,
Plasma electronics
E-mail: retsuo@ee.tokushima-u.ac.jp
Tel. +81-88-656-7441
Fax: +81-88-656-7441

 Prediction pixels generation using machine learning

crack

Fig. 1 Comparison of a conventional prediction pixels
and proposed
 LSI design of neural network for image processing
Represent complex neural network with ODE(Ordinary Differential Equation)

Applicable to image processing

Content:
As the AI ​/ IoT environment spreads to society, video
will continue to play a major role as a technique of
information transmission. In order to provide accurate
and detailed moving images, video codec technology isimplemented to various familiar devices. In the next
generation codec technology, because parallel
processing is difficult, an application to ultra-highresolution becomes more and more challenging. In thiswork, HEVC encoder is divided into two parts, ananalysis circuit (machine learning module) and an
encoding circuit (encoder) in order to establish a new
encoding structure with high compression whileachieving easy hardware implementation (Fig. 1).
Predicted pixels value close to ground truth can begenerated by embedding a machine learning module. In
the future, we will implement FPGA of ODE Network toestablish real-time processing of the image generation
network (Fig. 2, 3).
By completing this work, we aim to make a significant
contribution to the next-generation social infrastructure
environment called AI, IoT, and 5G.
Keywords：Video coding, Machine learning, LSI design
E-mail: t.katayama@tokushima-u.ac.jp
Tel. 088-656-7482
Fax: 088-656-7471
HP : http://pub2.db.tokushima-u.ac.jp/ERD/person/350321/profile-ja.html

Fig.2 ResNet and ODE Net structure

Fig. 3 FPGA(PYNQ-Z1)

Input Layer

Output Layer

Hidden Layer

TG x  i  TG y

R[ k ]Tx  i  R[ k ]Ty

V[ k ] x  i  V[ k ] y

12DesiredOutputR[ k ]R *[ k ] x  i  R[ k ]R *[ k ] y11Complex-valued NN

Swarm robots
150

t = 0.0 sᶁᶐᵿᶁᶉᴾ125

ermax

Y Axis [cm]100

Conveyance
TargetMobileRobotst = 31.0 s

75Desired conveyance orbit
50

Trajectory of conveyance target25

t = 63.0 s
0
0

25

50

75

100

125

150

175

X Axis [cm]150
St art125

Experimental Resultt = 0s200

Content:
The swarm robotics has a problem on the control
system design cause of voluminous measured
information and motion patterns. Therefore, we propose
the control system which uses soft computing scheme
e.g. neural networks (NN), fuzzy system and genetic
algorithm (GA).
The left figures are our proposed cooperative control
system for swarm robots using complex-valued NN(CVNN) and GA. The CVNN can treat a two dimensional
position information and adaptable for control of mobile
robots. The system inputs a position information for
CVNN and outputs a velocity vector and parameters of
CVNN are optimized by GA. We confirmed a tracking
performance for desired conveyance orbit, and a fault
tolerance performances of some robot’s breakdown.
Moreover, we propose an extraction system of humanoperation skills using datamining method and analyze abehavior of robots basis on simple motion rules.

t = 20 sY[c
Y AxisAxis [cm]100

75

ConveyanceOrbitt = 40 s

50

t = 67 s
Conveyance
T raject ory

25

Goal

0
0

25

50

75

100

125

150

X Axis [cm]Fault tolerance

175

200

Keywords䠖Swarm robotics, Machine learning,
Cooperative control
E-mail: suzuki.hiroshi@tokushima-u.ac.jp
Tel. +81-88-656-7455
Fax: +81-88-656-7455
HP : http://www-sky.ee.tokushima-u.ac.jp/

Incident
wavelength

Eigenmodes

Considerable
reflectivity variation
10-times forthat without MS

PeriodGas or Virus
adhesion
Minuscule RI change owing
crackto Gas or Virus adhesion→Eigenmode amplitudes and phases strongly depend on
the RI value of the ambient
Fig.1 Operation principle of RI sensing with meta-surface
Significant reflectivity
decreasing

Meta-surface(a)(b)
200 nmFig. 2 fabricated meta-surface(a)Optical image (b)SEM image
10-4 order RI change
can be detected
Fig. 3 Dependence of reflectivity
on the ambient RI value ns

Content:
Optical refractive index (RI) sensors is highly desirable
for many applications, such as gas-detection and biosensing. For these applications, high sensitivity andcompactness are required.
Highly sensitive compact RI sensor was demonstrated
with periodic meta-surface (MS), whose dimension issmaller than the incident wavelength (Fig.1). The
amplitude and phase of the optical eigenmodes resulting
from the subwavelength periodicityof the MS
considerably depend on the ambient RI. As a result,highly sensitive RI sensing can be realized.
We fabricated the MS on GaN substrate (Fig. 2). The
Blue-violet light is strongly reflected owing to thestructure. Utilizing the eigenmodes in the MS, 10-4 order
RI can be experimentally detected with very compact andsimple optical system, as shown in Fig. 3. Our sensor isvery suitable for the integrated devices for gas- and biosensing due to its high sensitivity and compactness
Keywords ： Meta-surface, Subwavelength, Refractive
index sensor
E-mail: takashima@tokushima-u.ac.jp
Tel. <電話番号 +81-88-656-7438>
Fax: <fax番号 +81-88-656-7438>