4 citations · 18 across the 15 of their papers we have counts for
15 papers
Asymmetric Encoding-Decoding Schemes for Lossless Data Compression
Hirosuke Yamamoto, Ken-ichi Iwata
This paper proposes a new lossless data compression coding scheme named an asymmetric encoding-decoding scheme (AEDS), which can be considered as a generalization of tANS (tabled v…
Reduction of Sufficient Number of Code Tables of -Bit Delay Decodable Codes
Kengo Hashimoto, Ken-ichi Iwata
A -bit delay decodable code-tuple is a lossless source code that can achieve a smaller average codeword length than Huffman codes by using a finite number of code tables and all…
Encoding and Decoding Algorithms of ANS Variants and Evaluation of Their Average Code Lengths
Hirosuke Yamamoto, Ken-ichi Iwata
Asymmetric Numeral Systems (ANS) proposed by Jarek Duda are high-performance distortionless data compression schemes that can achieve almost the same compression performance as ari…
The Optimality of AIFV Codes in the Class of -bit Delay Decodable Codes
Kengo Hashimoto, Ken-ichi Iwata
AIFV (almost instantaneous fixed-to-variable length) codes are noiseless source codes that can attain a shorter average codeword length than Huffman codes by allowing a time-varian…
Properties of k-bit Delay Decodable Codes
Kengo Hashimoto, Ken-ichi Iwata
The class of k-bit delay decodable codes, source codes allowing decoding delay of at most k bits for k >= 0, can attain a shorter average codeword length than Huffman codes. This p…
Optimality of Huffman Code in the Class of 1-bit Delay Decodable Codes
Kengo Hashimoto, Ken-ichi Iwata
For a given independent and identically distributed (i.i.d.) source, Huffman code achieves the optimal average codeword length in the class of instantaneous code with a single code…
Countably Infinite Multilevel Source Polarization for Non-Stationary Erasure Distributions
Yuta Sakai, Ken-ichi Iwata, Hiroshi Fujisaki
Polar transforms are central operations in the study of polar codes. This paper examines polar transforms for non-stationary memoryless sources on possibly infinite source alphabet…
Modular Arithmetic Erasure Channels and Their Multilevel Channel Polarization
Yuta Sakai, Ken-ichi Iwata, Hiroshi Fujisaki
This study proposes \emph{modular arithmetic erasure channels} (MAECs), a novel class of erasure-like channels with an input alphabet that need not be binary. This class contains t…
Asymptotic Distribution of Multilevel Channel Polarization for a Certain Class of Erasure Channels
Yuta Sakai, Ken-ichi Iwata, Hiroshi Fujisaki
This study examines multilevel channel polarization for a certain class of erasure channels that the input alphabet size is an arbitrary composite number. We derive limiting propor…
Proceedings of Workshop AEW10: Concepts in Information Theory and Communications
Kees A. Schouhamer Immink, Stan Baggen, Ferdaous Chaabane +31
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 cooperati…
Sharp Bounds on Arimoto's Conditional Rényi Entropies Between Two Distinct Orders
Yuta Sakai, Ken-ichi Iwata
This study examines sharp bounds on Arimoto's conditional Rényi entropy of order with a fixed another one of distinct order . Arimoto inspired the relation between the…
Sharp Bounds Between Two Rényi Entropies of Distinct Positive Orders
Yuta Sakai, Ken-ichi Iwata
Many axiomatic definitions of entropy, such as the Rényi entropy, of a random variable are closely related to the -norm of its probability distribution. This study consider…
A Generalized Erasure Channel in the Sense of Polarization for Binary Erasure Channels
Yuta Sakai, Ken-ichi Iwata
The polar transformation of a binary erasure channel (BEC) can be exactly approximated by other BECs. Arıkan proposed that polar codes for a BEC can be efficiently constructed by u…
Relations Between Conditional Shannon Entropy and Expectation of -Norm
Yuta Sakai, Ken-ichi Iwata
The paper examines relationships between the conditional Shannon entropy and the expectation of -norm for joint probability distributions. More precisely, we investigate th…
Extremal Relations Between Shannon Entropy and -Norm
Yuta Sakai, Ken-ichi Iwata
The paper examines relationships between the Shannon entropy and the -norm for -ary probability vectors, . More precisely, we investigate the tight bounds of th…