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No. 63Feb. 2020

2020 Japan Prize Laureates Announced

Prof. Robert G. Gallager

Dr. Svante Pääbo

Professor Emeritus, Massachusetts Institute of Technology

Professor, Max Planck Institute for Evolutionary Anthropology

USA

SwedenEligible Field: “Electronics, Information, Communication”

Eligible Field: “Life Science”

Pioneering contribution to informationand coding theory

Pioneering contributions to paleoanthropology
through decoding ancient human genome sequences

From general communication devices such as TVs, personal
computers and mobile phones to cutting-edge researches utilizing
big-data, such as particle physics and astronomy, digital
information communication is one of the fundamental
technologies that support today's society. However, when
performing data communication, errors can occur due to external
noise, and for many years, a lot of research was conducted on
developing detection and correction schemes for such errors.
Among them, LDPC codes (Low-Density Parity-Check
Codes), invented by Prof. Robert G. Gallager, is an extremely
reliable and practical scheme.
Starting with its adoption in the fifth-generation mobile
communication system (5G), LDPC codes are expected tosupport the coming generations of high-speed and large-capacity
communications.

Where did we humans come from?
Elucidating “the origin and evolution of modern humans” is
one of the biggest challenges in paleoanthropology. Traditionally,
the evolution and classification of humans had been approached
by analyzing the shape of excavated bone and teeth fossils.
However, from the mid-1980s, Dr. Svante Pääbo adopted the“genetic approach” , which involves extracting and analyzing
DNA, and made series of discoveries that have enabled us tounderstand modern human evolution at much greater depth.
In particular, the DNA analysis of Neanderthals revealed thatthe ancestors of modern humans interbred with Neanderthals.
Furthermore, the DNA from a fossilized bone fragment excavatedfrom the Denisova cave in Russia revealed the existence of apreviously unknown species of humans called the Denisovans.
By analyzing the DNA of ancient humans, Dr. Pääbo has shed
new light on the fundamental question of where modern humans
came from.

The creation of the Japan Prize was motivated by the Japanese
government's desire to "express gratitude to international society by
establishing a prestigious international award in the fields of science andtechnology". Supported by numerous donations, the Japan Prize wasestablished in 1983 with a cabinet endorsement.
The Japan Prize honors those who have made significant achievements that
contribute to the peace and prosperity of mankind, based not only on
contributions to the advancement of science and technology but also on social

contributions to our lives.
The award covers all fields of science and technology and takes into
consideration the developments in science and technology. Every year, thefoundation designates two fields for the award presentation.
One award is given for each field as a general rule. Each laureate receives
a certificate of merit and a prize medal. A cash prize of 50 million yen is alsopresented to each prize category.

”

row or column is odd and is 0 otherwise. Then if an error occurs intransmission in a particular row and column, the check digit for thatrow or column is odd and is 0 otherwise. Then if an error occurs incolumn and row would indicate the location of the error, and it could
transmission in a particular row and column, the check digit for thatbe corrected.
columnand row would indicate the location of the error, and it could
Much research in the 1950's was devoted to improving this approach,be corrected.
includingthe Hamming
the BCH
codes, thistheapproach,
RS codes, andMuch researchin the 1950'scodes,
was devoted
to improving
LDPC codes.
All thesecodes,
schemes
replacethe rows
andcodes,columns
includingthe Hamming
the BCH
codes,
the RSand of data
LDPC
Allarbitrary
these schemes
replacerows andcolumnsof datacheck isabovecodes.
with ancollection
ofthe
subsetsof data.
A parity
above
with an arbitrarycollectionof subsets
data.
A parityaccording
check is to thethen appended
to eachsubset anderrorsofare
corrected
thenappendedeachwhichsubset haveand errors
are correctedto theparitycheck todigitsthe wrongparity according
after transmission.
paritydigits codes
which havethe wrongparityafter transmission.
In checkthe LDPC
inventedby Prof.
Gallager,the overall block ofIn the LDPC codes invented by Prof. Gallager, the overall block ofdata
was chosen to be very large, but each of the above subsets weredata was chosen to be very large, but each of the above subsets werechosenquite
small,
a choice
to simplify
the implementation
chosen toto
bebe
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correction.
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these
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at aof error correction. He showed that these subsets could be
keptbeat keptafixedsmall
small
size
while
increasing
the length
the overall
fixed
size
while
increasing
the lengthof theof
overall
block soblock
as so asapproachchannelcapacityhighlyreliabletransmission.
totoapproachchannelcapacity
withwithhighlyreliabletransmission.

“Electronics, Information, Communication” Field“Electronics, Information, Communication” Field
Achievement : Pioneering contribution to information andcoding theory

Achievement : Pioneering contribution to information andcoding theory

Prof. Robert G. Gallager (USA)88)
Born: May
1931 (Age:Prof.29,Robert
G. Gallager(USA)
Professor
Emeritus,
Born:
May 29, Massachusetts
1931 (Age: 88) Institute of Technology

Professor Emeritus, Massachusetts Institute of Technology

Error correction schemes in digital information
Error correction schemes in digital information
communication
communication

To realize
remotesurgeries
andandautonomous
driving,
To realize
remotesurgeries
autonomous
driving,ititisisindispensindispensable toable
usetolow-latency
error-free
datadatatransmission.
use low-latency
error-freetransmission.InIn digital
digital datadatatransmission,
however,errorsmaymay
occur
in in
both
transmission,
however,errorsoccur
bothwired
wiredandand wirelesswireless
communications
due tonoisescausedby byproblems
communications
due
to noisescausedproblemsinincommunication
communicationequipmentor radiointerference.
Sincemost
mostofof these
these noises
noisesequipmentor radionoisenoiseinterference.
Since
be removed,
it is necessary
to devisea frameworktotodetect
detect andcannotcannot
be removed,
it is necessary
to devisea frameworkanderrors.
correctcorrectthese theseerrors.
the easiest
to achieve
sendduplicate
duplicate data.
data. If
One ofOne
theofeasiest
wayswaysto achieve
thisthisis is
to tosendIf
the data “01” is repeated three times and sent as “01 01 01”, even if an
the data“01”
isrepeated
three
times
and
sent
as
“01
01
01”,
even
if
an
error occurs and becomes “11 01 01” at the receiving end, the correct
error occurs
andcanbecomes“11 0101”majority
at the receiving
end, thedata “01”be recoveredby therule. The processof correct
addingdata “01”canberecoveredbythemajority
rule.
The
processofaddingextra data in such circumstances is called “coding”, and the processofextra datain suchcircumstances
is called“coding”,
the“decoding”.
process ofcorrecting
errorsand recovering
the original
data isandcalledcorrecting errors and recovering the original data is called “decoding”.

LDPC
becamemainstream
afterafter
2000 2000
LDPCcodes
codes
becamemainstream
LDPC codes were proposed by Prof. Gallager during the 1960s.
LDPC codes were proposed by Prof. Gallager during the 1960s.
However, because processing capability of computers were limited at
However,
because processing capability of computers were limited atthat time, his ideas were neglected for the next 30 years.
that
time,
ideas
were neglected
the nextrapidly
30 years.
From
the his1990s,
computerprocessingforcapability
enhanced,theinto1990s,
computerprocessingbecame
capability
and From
research
its practicalimplementation
active.rapidly
In 1998,enhanced,
itandprovenresearch
practical
implementation
becameactive.
In 1998, it
wasto beinto
the its
mosttheoreticallysuperior scheme,
and its
adoptionwastheprovento be the mosttheoreticallysuperior systems
scheme,advanced
and its adoption
intolarge-capacity
information
communication
drastically.
into the large-capacity information communication systems advanced
Since the 2000s, LDPC codes have been rapidly adopted in digital comdrastically.
munication
systems
anddigitalcodes
storagesystems.
digitalTV comSince the2000s,
LDPC
have
been These
rapidlyinclude
adoptedin digitalsatellite
broadcasting,
Gigabit
Ethernet,high-speed
data communication
systems10anddigitalstorageWiMAX
systems.
These include
digital TV
munication, and the 5th generation mobile communication system (5G),satellite
broadcasting,
10
Gigabit
Ethernet,
WiMAX
high-speed
data comas well as hard disks and solid-state drives. It has become an extremely
munication,
the 5ththat
generation
mobilecommunication
importantbasicandtechnology
supports ourmoderndigital society.system (5G),

Principle and features of LDPC codes

Principle and features of LDPC codes

This approach is, however, very wasteful of data and not very
reliable. A better approach, familiar to communication engineers inThis approach is, however, very wasteful of data and not very
the 1950's, was to arrange a block of data into rows and columns. A
reliable.
A check
betterdigit
approach,to andcommunicationengineersinparityis addedfamiliar
to each row
to each column,
as illustratthe 1950's,
to Thearrangeblockdigitof dataandofcolumns.
A
ed in wasFig. 2.
paritya checkis 1 into
if therows
numberones in thatparity check digit is added to each row and to each column, as illustrated in Fig. 2. The parity check digit is 1 if the number of ones in that

as well as hard disks and solid-state drives. It has become an extremely
important basic technology that supports our modern digital society.

Figure 1 Error correction schemes in digital information communication
Errors in digital data communication are inevitable due to noise

Errors can be detected and correctedby devising the transmitting data

Figure 1 Error correction schemes in digital information communication
Communication
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Technologies
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Currently, there are no other practical codes that can outperform LDPC

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processing
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row or column is odd and is 0 otherwise. Then if an error occurs intransmission in a particular row and column, the check digit for that
Figure 2 Ach“Life
Science”
columnand rowfieldwould indicate the location of the error, and it could
be corrected.
Nucle
Achievement: Pioneering
contributions
to paleoanthropology
Much researchin the 1950's
was devoted
to improving this approach,through decoding ancient human genome
including thesequences
Hamming codes, the BCH codes, the RS codes, and
LDPC codes. All these schemes replace the rows and columns of data
Dr.
Svante(Sweden)above
with Pääbo
an arbitrarycollection of subsets of data. A parity check is
Born:
April
20,
1955
(Age:
64)
then
appendedtoeachsubsetand errors are corrected according to theProfessor, Max Planck Institute for Evolutionary Anthropology
parity check digits which have the wrong parity after transmission.
In the LDPC codes invented by Prof. Gallager, the overall block of
data
chosenbe veryhumans
large, buteach of the above subsets were
The wasancestors
ofto
moderninterbredwith Neanderthals
chosento be quite small, a choice made to simplify the implementationof error correction. He showed that these subsets could be kept at a
fixedsmall size
the length
theexisted.
overallThey
block so as
Neanderthals
are awhile
speciesincreasingof archaic humans
that ofonce
approachchannelreliabletransmission.
lefttoAfrica
around500,000capacity
years agowith
and highly
spread acrossEuropeand theMitochondrial DN

blueprint of life,
Middle East, but became extinct about 40,000 years ago. For this reason,
becomes fragme
it was long thought that Neanderthals were unrelated to modern humans.
LDPC codes became mainstream after 2000
However, when Dr. Pääbo analyzed the DNA of excavated Neanderthal
Ancient DNbones, he discovered that modern humans had in fact inherited Neanderthal
same analo
LDPC
codes
were
proposedbyProf.
Gallagerduringthe
1960s.
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DNA.

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Figure1 The
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When the shumansinto the large-capacity informationModern
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munication systems and digital storage systems. These include digital TV
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Figure4 Technologies
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AI Intelligence
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cyberspace
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Noise
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and decoding restores

Big-data

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If the count of "1"s in a group is aneven number, the check symbol is set

match the data.
The ﬁfth "1" is incorrect because thethe original data.

“Electronics, Information, Communication” Field“Life Science” field
Achievement : Pioneering contribution to information andcoding theory

Achievement : Pioneering contributions to paleoanthropology

throughdecoding
Prof. Robert G. sequences
Gallager(USA)ancient human genome

Born: May 29, 1931 (Age: 88)Professor
Institute of Technology
Dr.Emeritus,
Svante Massachusetts
Pääbo (Sweden)

Born: April 20, 1955 (Age: 64)
Professor, Max Planck Institute for Evolutionary Anthropology

Error correction schemes in digital information
communicationar）

The ancestors of modern humans interbredwith Neanderthals
To realize remote surgeries and autonomous driving, it is indispensable to use
low-latency
data transmission.
In digital
data
Neanderthals
are aerror-free
species of archaic
humans that once
existed. Theytransmission,
however,errors may
both acrosswired Europe
and wirelessleft Africa
around 500,000
years occur
ago andinspreadand thecommunications
noisescausedby40,000
problems
communication
Middle East,due
but tobecameextinct
about
yearsinago.
For this reason,
equipment
radio
noise
Since
most toofmodern
these humans.
noisesit wasorlong
thoughtthat interference.
Neanderthals wereunrelatedcannot However,be removed,itisnecessarytodeviseaframeworktodetectandwhen Dr. Pääbo analyzed the DNA of excavated Neanderthal
correctbones,
these heerrors.
discovered that modern humans had in fact inherited Neanderthal
One DNA.
of the easiest ways to achieve this is to send duplicate data. If
the data “01” is repeated three times and sent as “01 01 01”, even if anerror occurs and becomes “11 01 01” at the receiving end, the correct
Figureancestorsby
ofthe
modernhumansinterbredwith Neanderthals
data “01”can1beTherecoveredmajorityrule.
The processof adding
extra data in500,000
such circumstances
is called“coding”, and40,000
the process of
400,000
60,000years agoand recovering
years ago
years ago data is called
years “decoding”.
ago
correcting errors
the originalorm LDPC
improve inr expand inModern humans
that were left in Africa

Principle and features of LDPC codes

The Middle East
This approach is, however, very wastefulof data and not very

e the future
Modern humans
Spread to Europein
The common
A better approach, familiar to communicationengineerso be highlyreliable.
that came out of Africa
and Asia
ancestor
was to arrange a block of data into rows and columns. A
ntly to thisthe 1950's,
in Africa
and to each column, as illustrathe variousparity check digit is added to each rowInterbred
for highered in Fig. 2. The parity check digit is 1 if the number of ones in that
Neanderthalsn.
Became extinct
Denisovans

Figure 1 Error correction schemes in digital information communication
Became extinct

ion

data

n

Errors in digital data communication are inevitable due to noise
Communication
Transmitting Achievements (1):channel
0 1
1 1
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“Electronics, Information, Communication” Field

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modernhumans interbredwith Neanderthals.

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communication

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as well as hard disks and solid-state drives. It has become an extremely
important basic technology that supports our modern digital society.

ng the theory
history, thereby contributing tremendously to the advancement of
n humans as Principle
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into the large-capacity information communication systems advanced
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ChairmanPrinciple
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emergence of d
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codingtheoryResources, Energy, Environment,
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He showedasthat
subsets
could be kept at atechnologies
relevant
to urban andsystems.
able to use
low-latency
error-free
datatransportationtransmission.
In digital data
fixed small size while increasing the length of the overall block so as
transmission, however, errors may occur in both wired and wirelessto approach channel capacity with highly reliable transmission.
Eligible Achievements:
communications due to noises caused by problems in communication
The 2021 Japan Prize in the field of "Resources, Energy, Environment, Social Infrastructure" is awarded to an individual(s) who has achieved
equipment or radio noise interference. Since most of these noises
breakthroughs in the creation, innovation or dissemination of science and technology,
therebycontributing
significantly
to thesustainable
LDPC codes
becamemainstream
after
2000
cannot be removed, it is necessary to devise a framework to detect anddevelopment of human society.
correct these errors.
One of the easiest
to achieve this is to send duplicate data. If
LDPC codes were proposed by Prof. Gallager during the 1960s.
Area waysofthe data “01”is repeatedthree times and sent as “01 01 01”, even if anLife Science,
Agriculture,
However,
because processing capability of computers were limited at
Medical Science, Medicinalthat
Scienceerror occurs and Medicine
becomes “11 01 01” at the receiving end, the correcttime, his ideas were neglected for the next 30 years.
data “01” canbe recoveredby the majority rule. The process of adding
From the 1990s, computer processing capability rapidly enhanced,
Backgroundand Rationale:
extra data inThesuchcircumstancesiscalled“coding”,
andtheprocessofand
its practicalimplementation
became active.
In 1998, it
field of medical science and medicinal science has been undergoing remarkableresearch
progress into
in recentyears. Genomic
medicine, regenerative
medicinecorrectingand
errorsand recovering the original data is called “decoding”.
was provenbe themost theoreticallysuperior
and
its adoption
medical robotics have been making rapid progress. Also, revolutionary medicines
such asto
cancerimmunotherapy
drugs andantiviralscheme,
agents are
being
into the large-capacity information communication systems advanced
developed one after another.
drastically.
Nonetheless,the needofforLDPC
new measuresdiseases associated with aging and changes in lifestyle, as well as the
Principle
and featurescodesagainst emerging infectious diseases andSince
the 2000s, LDPC codes have been rapidly adopted in digital comemergence of drug-resistant pathogens and cancers, have all come to the fore as major global issues.
munication systems and digital storage systems. These include digital TV
Today's medical science and medicinal science are expected to contribute even more to people’ s health and well-being. This is being sought through theThis approach is, however, very wasteful of data and not verysatellite broadcasting, 10 Gigabit Ethernet, WiMAX high-speed data comcreation and dissemination of new medical care that integrates other disciplines such as engineering and informatics, the development and production ofreliable. A better approach, familiar to communication engineers inmunication, and the 5th generation mobile communication system (5G),
drugs, and new drug delivery systems.
the 1950's,newwasto arrange a block of data into rows and columns. A
as well as hard disks and solid-state drives. It has become an extremely
Eligible:parity checkdigitAchievements
is added to eachrow and to each column, as illustratimportant basic technology that supports our modern digital society.
2021
Japancheck
Prize indigit
the field
Science,is awarded to an individual(s) who has achieved scientific and technologicaled in Fig. 2.The
The
parityis 1ofif"Medical
the number
ofMedicinal
ones in Science"
that“Electronics, Information, Communication” Field

Eligible Fields for the 2021 Japan Prize

breakthroughs, such as new discoveries or the development of innovative technologies on the "prevention", "diagnosis", "treatment" or "prognosis" of
diseases, thereby contributing towards the health and well-being of humankind.

Error correction
schemesin digital information
communication
Figure 1Fields
Selection
Committee
for the 2021
Japan Prize

Errors in digital
data communication are inevitable due to noiseMembers
ChairmanTransmitting
data
0 1

Distinguished Professor
Institute of Advanced Sciences

Counselor to the President, Japan Science and Technology Agency
Director, The Japan Prize
Foundation
Communication

0 1

Vice Chairman

channel(Wireless/Wired)

Errors can be detected and corrected

dataKyuma
Yozo Fujino by devising the transmitting
Kazuo

Michiharu Nakamura

Received
Yokohama NationalTransmitting
University
data Ken Furuya
data

1 1

CodingProfessor, Graduate School of Engineering
Soka University

Mariko Hasegawa

President
National Institute for Materials Science

President
SOKENDAI(The Graduate University for Advanced Studies)

Kohei Miyazono Noise

Masaru Kitsuregawa

Professor
Department of Molecular Pathology
Graduate School of Medicine, The University of Tokyo

channelEiichiNakamura(Wireless/Wired)1 1 0 1 0 1 Decoding

Endowed Professor
Office of the President and Department of Chemistry
The University of Tokyo

1 1 Professor Emeritus, The 0University
1of TokyoKazuhito Hashimoto

President
National
Agriculture and Food Research Organization
Communication

0 1 0 1 0 1

Director General, National Institute of Informatics
Professor, Institute of Industrial Science
The University of Tokyo

0 1

Yuichi Sugiyama

HeadSugiyama Laboratory, RIKEN Baton Zone Program

Noise
MarikoTakahashi
The Science Coordinator
The Asahi Shimbun

Masayuki Yamamoto

Figure 2 A simple example of using parity checks to correct errors

Professor Emeritus, The University of Tokyo
Professor Emeritus, National Institute for Basic Biology

Using the method of grouping and checking data(alphabetical order, titles as of November, 2019)

Schedule (2021-2023)

Received
data

Noise

The eligible fields100101011100010
for the Japan Prize (2021 to 2023) have100111011100010
been decided for the two research100101011
areas, respectively.
100101011
Realizing both high reliability
These fields
cycle.
Codingrotate every year in a three year
Transmission
Decoding
and eﬃciency
Every year the FieldsGroup
Selection
Committeeannounces the eligible
fields forthe next
three years.
Check
Check
Group
Group
Group
Group
Group
④
⑤
⑥
④
⑤
⑥
symbolsymbol(1) Use a large overall block length
Group
Group
1
0 Area0 of Physics,
1
0 Informatics,
0
1 Engineering100Chemistry,Areaof1（ok）
Life Science, Agriculture, Medicine①①
with randomly chosen groups in
Group
Group
0（error）
1
0
1
0
1
0
1
1
1
1
②
Year
Eligible place
Fields of horizontal and verticalYear ②
Eligible
Fields
Group
Group
0（ok）
0
1
1
0
1
1
0
0
1
1
③
③
2021
Resources, Energy, Environment, Social Infrastructure
2021
Medical Science, Medicinal Sciencegroups
Check
Check
0
1
0
Create vertical andhorizontal groups by
separating the data
into rows and columns

2022
2023

symbol0
10symbolMaterials,
Production
Electronics, Information, Communication

A check symbol is attached to each of
the vertical and horizontal groups.
If the count of "1"s in a group is aneven number, the check symbol is set（ok）（error）

（ok）

2022
2023

If there is an error in the received
data, the check symbols will notmatch the data.
The ﬁfth "1" is incorrect because the

Biological Production, Ecology/ Environment(2) Achieve simple decoding by using
Life Science

Correcting the errors
and decoding restoresthe original data.

groups of small size (low density)