# Jun MuramatsuNippon Telegraph and Telephone · NTT Communication Science Laboratories

Jun Muramatsu

Ph.D.

## About

107

Publications

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Introduction

**Skills and Expertise**

Additional affiliations

November 1995 - present

## Publications

Publications (107)

Stochastic encoders for channel coding and lossy source coding are introduced
with a rate close to the fundamental limits, where the only restriction is that
the channel input alphabet and the reproduction alphabet of the lossy source
code are finite. Random numbers, which satisfy a condition specified by a
function and its value, are used to const...

This paper reviews an approach to secret-key distribution based on the bounded observability (BO) model. First, the information-theoretic framework of secret-key agreement from a correlated random source is reviewed. Next, the BO model is introduced. In the context of this model, the BO condition is presented as a necessary and sufficient condition...

This paper revisits the theory of binary polar source/channel codes based on the bit error probability of successive-cancellation decoding. The polarization theorem is introduced based on the bit error probability and then techniques to compute the bit error probability are introduced. These techniques can be applied to the construction of polar co...

This paper investigates the achievability of the interference channel coding. It is clarified that the rate-splitting technique is unnecessary to achieve Han-Kobayashi and Jian-Xin-Garg inner regions. Codes are constructed by using sparse matrices (with logarithmic column degree) and the constrained-random-number generators. By extending the proble...

Channel codes for relayless networks with the general message access structure is introduced. It is shown that the multi-letter characterized capacity region of this network is achievable with this code. The capacity region is characterized in terms of entropy functions and provides an alternative to the regions introduced by [Somekh-Baruch and Ver...

We propose a two-level dimmer based on binary distribution matching where a low-rate signal controls the output probability distribution of a high-rate bit sequence, which can be used in region-of-interest (RoI) signaling applications. To reduce the rate loss of the dimmer, we propose the extended multiset-partition distribution matching (EMPDM) al...

We propose a probabilistic shaping approach for region-of-interest signaling, where a low-rate signal controls the desired probabilistic ranges of a high-rate data stream using a flexible distribution controller. In addition, we introduce run-length-aware values for frozen bit indices in systematic polar code to minimize the run-length without usin...

This paper introduces algorithms for the successive-cancellation decoding and the successive-cancellation list decoding of binary polar source/channel codes. By using the symmetric parametrization of conditional probability, we reduce both space and time complexity compared to the original algorithm introduced by Tal and Vardy.

Secret key distribution is a technique for a sender and a receiver to share a secret key, which is not known by any eavesdropper, when they share no common secret information in advance. By using this technique, the sender and the receiver can transmit a message securely in the sense that the message remains secret from any eavesdropper. We introdu...

We propose a novel decoding algorithm called “sampling decoding”, which is constructed using a Markov Chain Monte Carlo (MCMC) method and implements Maximum a Posteriori Probability decoding in an approximate manner. It is also shown that sampling decoding can be easily extended to universal coding or to be applicable for Markov sources. In simulat...

In 1989 we organized the first Benelux‐Japan workshop on Information and Communication theory in Eindhoven, the Netherlands. This year, 2019 we celebrate 30 years of our friendship between Asian and European scientists at the AEW11 in Rotterdam, the Netherlands. Many of the 1989 participants are also present at the 2019 event. This year we have man...

This year, 2019 we celebrate 30 years of our friendship between Asian and European scientists at the AEW11 in Rotterdam, the Netherlands. Many of the 1989 participants are also present at the 2019 event. This year we have many participants from different parts of Asia and Europe. It shows the importance of this event. It is a good tradition to pay...

This paper investigates the error probability of several decoding methods for a source code with decoder side information, where the decoding methods are: 1) symbol-wise maximum a posteriori decoding, 2) successive-cancellation decoding, and 3) stochastic successive-cancellation decoding. The proof of the effectiveness of a decoding method is reduc...

A construction of a channel code by using a source code with decoder side information is introduced. For the construction, any pair of encoder and decoder of a source code with decoder side information is available. Constrained-randomnumber generators, which generate random numbers satisfying a condition specified by a function and its value, are u...

A general multi-terminal source code and a general multi-terminal channel code are presented. Constrained-random-number generators with sparse matrices, are used in the construction of both encoders and decoders. Achievable regions for source coding and channel coding are derived in terms of entropy functions, where the capacity region for channel...

In this paper, we investigate the problems of uniform random number generation, independent uniform random number generation, and secret key agreement, which provide the information theoretic security. We consider the strong uniformity and strong independence, where it has been unclear whether or not sparse matrices can be applied to these problems...

We demonstrate physical implementation of information-theoretic secure oblivious transfer based on bounded observability using optical correlated randomness in semiconductor lasers driven by common random light broadcast over optical fibers. We demonstrate that the scheme can achieve one-out-of-two oblivious transfer with effective key generation r...

The 10th Asia-Europe workshop in "Concepts in Information Theory and Communications" AEW10 was held in Boppard, Germany on June 21-23, 2017. It is based on a longstanding cooperation between Asian and European scientists. The first workshop was held in Eindhoven, the Netherlands in 1989. The idea of the workshop is threefold: 1) to improve the comm...

In this talk, we introduce the concept of CoCoNuTS (Codes based on Constrained Numbers Theoretically-achieving the Shannon limits). This concept provides building blocks for codes achieving the fundamental limits. Our study on the construction of codes achieving the Shannon limits has been continued for over ten years. Tools for the code constructi...

This paper investigates the error probability of a stochastic decision and the way in which it differs from the error probability of an optimal decision, i.e., the maximum a posteriori decision. It is shown that the error probability of a stochastic decision with the a posteriori distribution is at most twice the error probability of the maximum a...

The construction of a channel code by using a source code with decoder side information is introduced. For the construction, any pair of encoder and decoder is available for a source code with decoder side information. A constrained-random-number generator, which generates random numbers satisfying a condition specified by a function and its value,...

A variable-length lossy source code is introduced with a rate-distortion pair close to the rate-distortion function. Random numbers that satisfy a condition specified by a function and its value are used to construct a stochastic encoder. The proof of the theorem is based on the balanced-coloring property of an ensemble of functions. Since an ensem...

A variable-length lossy compression algorithms for a stationary memoryless source with a continuous alphabet are introduced with a rate-distortion pair close to the rate-distortion function.

Limit superior/inferior in probability are fundamental tools for the information spectrum method developed by Han and Verdú, where there is no restriction on the source or channel such as stationarity. The equivalent expressions of these limits are derived and alternative formulas for the fundamental limits of source coding, uniform random number g...

The coding problem for a wiretap channel with a noncausal state is investigated, where the problem includes the coding problem for a channel with a noncausal state, which is known as the Gel'fand-Pinsker problem, and the coding problem for a wiretap channel introduced by Wyner. The secrecy capacity for this channel is derived, where an optimal code...

In 1973, D. Slepian and J. K. Wolf proved a theorem on the coding problem of correlated sources. The history of this theorem is reviewed from the viewpoint of achievability proofs (code construction). This article is written in Japanese.

We experimentally investigate common-signal-induced synchronization in cascaded semiconductor lasers for the purpose of secure key distribution. We show that information-theoretic secure key distribution can be achieved using this system.

The aim of this paper is to investigate relationship between inner regions for broadcast channel codes transmitting common and private messages. One of the regions is known as the Marton inner region, another region was derived by Gel'fand and Pinsker, and yet another is obtained from the saturation property and collision-resistance property. Altho...

It has been proposed that a secure key distribution scheme using correlated random bit sequences can be implemented using common random-signal induced synchronization of semiconductor laser systems. In this scheme it is necessary to use laser systems consisting of multiple cascaded lasers to be secure against a powerful eavesdropper. In this paper,...

A stochastic encoder for channel coding is introduced with a rate close to the channel capacity, where the only restriction is that the channel input alphabet is finite. Random numbers, which satisfy a condition specified by a function and its value, are used to construct the stochastic encoder. The proof of the theorem is based on the hash propert...

There is a flaw in the statement of Lemma 5 in the above titled paper (ibid., vol. 56, no. 5, pp. 2143-2167, May 2010), which is used in the proof of Ths. 4, 6, and 7 in the same paper. Revisions are presented here.

We report physical random bit generation with on-chip chaos lasers. The design of the laser device is based on a theoretical model for non-deterministic random bit generation by amplification of microscopic noise. It is shown that the bit sequences generated at rates up to 2.08 gigabit per second (Gbit/s) pass a standard statistical test suite of r...

The aim of this paper is to introduce the construction of codes for a general
discrete stationary memoryless multiple access channel based on the the notion
of the hash property. Since an ensemble of sparse matrices has a hash property,
we can use sparse matrices for code construction. Our approach has a potential
advantage compared to the conventi...

We investigate the problem of (independent) uniform random number generation and secret key agreement. A generator for the (independent) uniform random numbers is constructed by using a sparse matrix and it is applied to a secret key agreement protocol with strong secrecy. It is proved that the rate of the proposed codes can achieve the fundamental...

An LDPC matrix is used as a local encoding kernel at each link to construct a universal code to address network coding problems. It is also shown that at each terminal node the global encoding kernel that constructs a decoder becomes an LDPC matrix. This provides the perspective that decoding complexity can be reduced to a linear order of a block l...

We experimentally and numerically observe the synchronization between two semiconductor lasers induced by common optical injection with constant-amplitude and random-phase modulation in configurations with and without optical feedback. Large cross correlation (~0.9) between the intensity oscillations of the two response lasers can be achieved altho...

There are flaws in the proof of Ths. 1 and 3 in the above titled paper (ibid., vol 56, no. 6, pp. 2688-2698, Jun. 2010). Corrections are provided here.

We theoretically show that completely stochastic fast physical random bit generation at a rate of more than one gigabit per second can be realized by using lasers with optical delayed feedback which creates high-dimensional chaos of laser light outputs. The theory is based on the mixing property of chaos, which transduces microscopic quantum noise...

We propose a secure key distribution scheme based on correlated physical randomness in remote optical scramblers driven by common random light. The security of the scheme depends on the practical difficulty of completely observing random optical phenomena. We describe a particular realization using the synchronization of semiconductor lasers inject...

The aim of this paper is to prove coding theorems for the wiretap channel and the secret key agreement based on the the notion of a hash property for an ensemble of functions. These theorems imply that codes using sparse matrices can achieve the optimal rate. Furthermore, fixed-rate universal coding theorems for a wiretap channel and a secret key a...

Sparse matrix codes for the channel coding problem and the lossy source coding problem on a continuous alphabet are constructed. The constructed codes are universal codes that do not depend on the statistical property of the communication systems. Coding theorems are shown for each problem.

A strongly secure wiretap channel code is proposed. The construction is based on the strong hash property introduced in Proc. ISIT2010, pp. 575-579. Since an ensemble of sparse matrices satisfies the conditions for the strong hash property, the rate of the proposed code using sparse matrices can achieve the secrecy capacity.

This paper introduces the notion of a hash property for an ensemble of functions and the basic lemmas of this property. This notion provides a sufficient condition for the achievability of coding theorems. A lossy source code, and a channel code for a general (asymmetric) channel are introduced based on the hash property. Since an ensemble of q-ary...

In the above titled paper (ibid., vol. 56, no. 5, pp. 2143-2167, May 10, there is a gap in the proof of Theorem 4. The corrections are provided here.

The aim of this paper is to prove the fixed-rate universal coding theorems by using the notion of the hash property. These theorems are the fixed-rate lossless universal source coding theorem and the fixed-rate universal channel coding theorem. Since an ensemble of sparse matrices (with logarithmic column degree) satisfies the hash property require...

The aim of this paper is to prove theorems for the Slepian-Wolf source coding
and the broadcast channel coding (independent messages and no common message)
based on the the notion of a stronger version of the hash property for an
ensemble of functions. Since an ensemble of sparse matrices has a strong hash
property, codes using sparse matrices can...

The aim of this paper is to construct a code for broadcast channel (independent messages and no common message) based on the the notion of a stronger version of the hash property for an ensemble of functions. Since an ensemble of sparse matrices has a strong hash property, codes using sparse matrices can achieve an inner bound of capacity region.

The aim of this paper is to prove the achievability of rate regions for several coding problems by using sparse matrices (with logarithmic column degree) and maximum-likelihood (ML) coding. These problems are the Gel'fand-Pinsker problem, the Wyner-Ziv problem, and the one-helps-one problem (source coding with partial side information at the decode...

Under the condition that all users can observe a common object, each using an observation function independently chosen from
the same limited set of observation functions, we show necessary and sufficient conditions for users to be able to generate
secret keys by public discussion.

The aim of this paper is to construct wiretap channel codes based on the the notion of a hash property for an ensemble of functions (sparse matrices). The theorem implies that codes using sparse matrices can achieve the optimal rate. Furthermore, the fixed-rate universal coding theorem for a wiretap channel is also presented.

The aim of this paper is to prove the achievability of the general (asymmetric) channel coding problem based on the hash property. Since an ensemble of q-ary sparse matrices (the maximum column weight grows logarithmically in the block length) satisfies the hash property, it is proved that the rate of codes using sparse matrices can achieve the cha...

The aim of this paper is to prove coding theorems for the wiretap channel
coding problem and secret key agreement problem based on the the notion of a
hash property for an ensemble of functions. These theorems imply that codes
using sparse matrices can achieve the optimal rate. Furthermore, fixed-rate
universal coding theorems for a wiretap channel...

A lossy source coding algorithm is presented that employs lossless multi-terminal source codes. By using nearly optimal lossless multi-terminal source codes, the proposed algorithm achieves the rate-distortion limit. The construction of lossless multi-terminal source codes, which are needed for the lossy source coding algorithm, can be realized by...

We studied synchronization induced by a common external noise in scalar time-delay systems. We have found a set of sufficient conditions for the synchronization. This set of conditions shows that the synchronization occurs in a wide class of time-delay systems. Numerical evidence for the analytically obtained conditions is also presented.

A channel code is constructed using sparse matrices for stationary memoryless channels that do not necessarily have a symmetric property like a binary symmetric channel. It is also shown that the constructed code has the following remarkable properties: 1) Joint source-channel coding: Combining with lossy source code, which is also constructed by s...

The aim of this paper is to prove the achievability of the Wyner-Ziv source coding problem by using sparse matrices and maximal-likelihood (ML) coding. To this end, the notion of a hash property for an ensemble of functions is introduced. For example, an ensemble of q-ary sparse matrices satisfies the hash property. Based on this property, it is pr...

Research into applying LDPC code theory, which is used for channel coding, to source coding has received a lot of attention in several research fields such as Distributed Source Coding. In this paper a source coding problem with a fidelity criterion is considered. Matsunaga et al. [6] constructed a lossy code under the conditions of a binary alphab...

Chaos synchronization of two semiconductor lasers commonly driven by a chaotic semiconductor laser subject to optical feedback was observed. Strongly correlated chaos synchronization between the two response lasers was observed even when the correlation between the drive and response lasers was low. It is shown that the cross correlation between th...

This paper introduces some results related to secret key agreement. We consider the situation in which legitimate users Alice and Bob and an eavesdropper Eve each has access to a correlated source. To transmit messages securely, Alice and Bob must agree on a secret key. Secret key agreement is the procedure for agreeing on a secret key by exchangin...

An operation that permutes symbols in a sequence is used for several coding algorithms. The probability distribution of the permuted source is investigated, where the permutation is selected at random with a uniform distribution. Moreover, the entropy of the permuted source and the mutual information shared by the original and permuted sources are...

We experimentally and numerically observe synchronization of two semiconductor lasers commonly driven by a chaotic semiconductor laser subject to optical feedback. Under condition that the relaxation oscillation frequency is matched between the two response lasers, but mismatched between the drive and the two response lasers, we show that it is pos...

The capacity for secret key agreement for permutation-invariant and symmetric sources under a sampling attack is investigated. The supremum of the normalized secret key capacity is introduced, where the supremum is taken over all permutation-invariant sources or all symmetric sources and the normalized secret key capacity is the secret key capacity...

Our results on secret key agreement from correlated sources are presented.

Secret key agreement is a procedure for agreeing on a secret key by exchanging messages over a public channel when a sender, a legitimate receiver (henceforth referred to as a receiver), and an eavesdropper have access to correlated sources. Maurer [6] defined secret key capacity, which is the least upper bound of the key generation rate of the sec...

Secret key agreement is a procedure for agreeing on a secret key by exchanging messages over a public channel when a sender, a legitimate receiver and an eavesdropper have access to correlated sources. Maurer, IEEE Trans. Inf. Theory 1993 defined secret key capacity, which is the least upper bound of the key generation rate of the secret key agreem...

This paper deals with a secret key agreement problem from correlated random numbers. It is proved that there is a pair of linear matrices that yields a secret key agreement in the situation wherein a sender, a legitimate receiver, and an eavesdropper have access to correlated random numbers. A relation between the coding problem of correlated sourc...

Linear codes for a coding problem of correlated sources are considered. It is proved that we can construct codes by using low-density parity-check (LDPC) matrices with maximum-likelihood (or typical set) decoding. As applications of the above coding problem, a construction of codes is presented for multiple-access channel with correlated additive n...

A threshold system is a typical sys-tem that shows noise-induced response to weak in-put, called stochastic resonance. When this system is considered as a digital communication channel, noise-assisted information transmission can in some cases be observed in the sense that a subthreshold binary sig-nal can be transmitted by adding moderate noise in...

This paper considers the capacity for secret key agreement under a sampling attack. Given the number of the eavesdropper's sources, we evaluate the secret key capacity bound which is defined as the supremum of the secret key capacity divided by the description length of the alphabet, where the supremum is taken over a set of probability distributio...

The explicit construction of a universal source code for correlated sources is presented. The construction is based on a technique of simulated random coding algorithms [5]. The proposed algorithm simulates the random generation of linear codes. For every pair of correlated sources whose achievable rate region includes a given pair of encoding rate...

We propose source coding algorithms that use the randomness of a past sequence. The proposed algorithms solve the problems of multi-terminal source coding, rate-distortion source coding, and source coding with partial side information at the decoder. We analyze the encoding rate and the decoding error rate in terms of almost-sure convergence.

In 1973, Slepian and Wolf clarified the necessary and sufficient conditions for coding rate of the correlated source coding problem, where the sources are separately encoded and codewords are decoded by a single decoder with an arbitrarily small decoding error. The purpose of this paper is to introduce theorems stating that such a code can be appli...

High-dimensional neural networks, such as complex neural networks and three-dimensional neural networks, have been proposed. They are capable of learning high-dimensional motions, which cannot be done by real-valued neural networks. In this paper, high-dimensional neurons are defined as vectors, and certain high-dimensional neural networks, such as...

This paper considers linear matrices for a coding problem for correlated sources. It is proved that we can construct codes by using sparse matrices, which are also called low density parity check (LDPC) matrices.

Source coding algorithms that use the randomness of a past sequence are proposed. The encoding rate and the decoding error rate in terms of almost-sure convergence are analyzed.

Recently, Muramatsu proposed source coding algorithms that use the randomness of a past sequence. The technique of his source coding algorithms is one method of constructing codes from the technique of random coding. By using his technique, we propose a channel coding algorithm with random numbers which can be observed by both the encoder and the d...

The paper considers linear matrices for a coding problem for multiple access networks. It is proved that we can construct codes by using sparse matrices, which are also called low density parity check (LDPC) matrices.

Bounds on the redundancy of the recency-rank and block-sorting
universal lossless data compression algorithms for finite-length
sequences are presented. These algorithms are asymptotically optimal for
infinite-length sequences, stationary ergodic sources in the almost-sure
sense, and asymptotically mean stationary sources in the average and
almost-...

Wyner and Ziv considered the rate-distortion function for source coding with side information at the decoder (we call the Wyner-Ziv problem). In this paper we show an information-spectrum approach to the Wyner-Ziv problem for general class of nonstationary and/or nonergodic sources with side information at the decoder, where the distortion measure...

We consider the new problem of generating asymptotically mutually independent and uniformly distributed random numbers from correlated sources and determine the achievable rate region for this problem.

We present that the output distribution of lossless source encoders with correlated side information is asymptotically independent of the side information. Based on this, we can construct a random number generator that produces mutually asymptotically independent random sequences from random sequences emitted from correlated sources

Source coding theorems for general sources are presented. For a
source μ, which is assumed to be a probability measure on all strings
of an infinite-length sequence with a finite alphabet, the notion of
almost-sure sup entropy rate is defined; it is an extension of the
Shannon entropy rate. When both an encoder and a decoder know that a
sequence is...

For a source μ, which is assumed to be a probability measure on
all strings of infinite length sequence with a finite alphabet, the
notion of the almost-sure entropy rate is defined; it is an extension of
the Shannon (1948) entropy rate. When both an encoder and a decoder know
that a sequence is generated by μ, the optimal almost sure source
coding...

## Projects

Projects (5)

Constructions of universal lossy source codes based on the complexity of sequence