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Hitoshi Yanami

Bio: Hitoshi Yanami is an academic researcher from Fujitsu. The author has contributed to research in topics: Quantifier elimination & Symbolic computation. The author has an hindex of 11, co-authored 79 publications receiving 453 citations.


Papers
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Proceedings ArticleDOI
03 Aug 2009
TL;DR: An effective symbolic-numeric cylindrical algebraic decomposition (SNCAD) algorithm and its variant specially designed for QE are proposed based on the authors' previous work and the implementation of those is reported.
Abstract: Recently quantifier elimination (QE) has been of great interest in many fields of science and engineering. In this paper an effective symbolic-numeric cylindrical algebraic decomposition (SNCAD) algorithm and its variant specially designed for QE are proposed based on the authors' previous work and our implementation of those is reported. Based on analysing experimental performances, we are improving our design/synthesis of the SNCAD for its practical realization with existing efficient computational techniques and several newly introduced ones. The practicality of the SNCAD is now examined by a number of experimental results including practical engineering problems, which also reveals the quality of the implementation.

54 citations

Book ChapterDOI
02 Apr 2001
TL;DR: A new symmetric key block cipher SC2000 with 128-bit block length and 128-,192-,256- bit key lengths and the fast software implementations are available by using the techniques of putting together S-boxes in various ways and of the Bitslice implementation.
Abstract: In this paper, we propose a new symmetric key block cipher SC2000 with 128-bit block length and 128-,192-,256- bit key lengths. The block cipher is constructed by piling two layers: one is a Feistel structure layer and the other is an SPN structure layer. Each operation used in two layers is S-box or logical operation, which has been well studied about security. It is a strong feature of the cipher that the fast software implementations are available by using the techniques of putting together S-boxes in various ways and of the Bitslice implementation.

35 citations

Proceedings ArticleDOI
02 Sep 2004
TL;DR: A MATLAB toolbox for robust parametric control based on a parameter space approach accomplished by QE, and how to merge the numerical computation and the symbolic operation to make the new design methods more efficient in practical control design is developed.
Abstract: We propose a new method with a software tool for parametric robust control synthesis by symbolic-numeric computation. The method is a parameter space approach and it is especially effective for analysis and design of fixed structure controllers of rational type. The real quantifier elimination (QE), which is one of the recent progresses in the symbolic computation, plays a key role in our development The QE-based approach can uniformly deal with a lot of important design specifications for robust control such as frequency restricted H/sub /spl infin// norm constraints, stability (gain/phase) margin and stability radius specifications, and pole location requirement by reducing such specifications to a particular type of formulas called a "sign definite condition (SDC)". This is also useful for improving the efficiency of QE computations since we can utilize an efficient QE algorithm specialized to the SDC. We have developed a MATLAB toolbox for robust parametric control based on a parameter space approach accomplished by QE. The QE-based parameter space approach and numerical simulation of specifications for specific controller parameter values taken from a controller parameter space are integrated conveniently in our toolbox with the assistance of a graphical user interface. This enables control engineers to achieve multi-objective robust controller synthesis smoothly. We also discuss how to merge the numerical computation and the symbolic operation to make our new design methods more efficient in practical control design.

24 citations

Patent
01 Jun 2001
TL;DR: In this paper, an extended key-preparing equipment for the case where a common key cryptosystem is applied is described, and a recording medium used therefor is provided.
Abstract: Intermediate data ai, bi, ci, and di are prepared by an intermediate data preparing equipment 4 from a cryptographic key through a nonlinear type function operation and the like, an extended key preparing equipment 5 selects a [Xr], b [Yr], c [Zr], and d [Wr] corresponding to the number of stages r from the intermediate data, and rearranges the data as well as conducts that of bit operation to prepare extended keys, whereby an extended key preparing apparatus by which an extended key required in the case where common key cryptosystem is applied can be safely prepared at a high speed, a process for preparing such an extended key, and a recording medium used therefor are provided.

20 citations

Book ChapterDOI
Hitoshi Yanami1, Hirokazu Anai1
06 Jun 2004
TL;DR: New functions in Maple-package SyNRAC, for solving real algebraic constraints derived from various engineering problems, are presented, including new simplifiers of formulas on Maple.
Abstract: In this paper we present newly developed functions in Maple-package SyNRAC, for solving real algebraic constraints derived from various engineering problems. The current version of SyNRAC provides quantifier elimination (QE) for the quadratic case and an environment dealing with first-order formulas over the reals (including new simplifiers of formulas) on Maple.

20 citations


Cited by
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Patent
31 Aug 2011
TL;DR: In this article, a method for modifying an image is presented, which consists of displaying an image, the image comprising a portion of an object; determining if an edge of the object is in a location within the portion; and detecting movement in a member direction, of an operating member with respect to the edge.
Abstract: A method is provided for modifying an image. The method comprises displaying an image, the image comprising a portion of an object; and determining if an edge of the object is in a location within the portion. The method further comprises detecting movement, in a member direction, of an operating member with respect to the edge. The method still further comprises moving, if the edge is not in the location, the object in an object direction corresponding to the detected movement; and modifying, if the edge is in the location, the image in response to the detected movement, the modified image comprising the edge in the location.

434 citations

Book ChapterDOI
01 Aug 2003

349 citations

Patent
21 May 2004
TL;DR: In this paper, a data storage and retrieval device and method is described, which includes at least one magnetic storage medium configured to store target data and at least a re-configurable logic device comprising an FPGA coupled to the at least 1 magnetic medium and configured to read a continuous stream of target data therefrom, having been configured with a template or as desired to fit the type of search and data being searched.
Abstract: A data storage and retrieval device and method is disclosed. The device includes at least one magnetic storage medium configured to store target data and at least one re-configurable logic device comprising an FPGA coupled to the at least one magnetic storage medium and configured to read a continuous stream of target data therefrom, having been configured with a template or as otherwise desired to fit the type of search and data being searched. The re-configurable logic device is configured to receive at least one search inquiry in the form of a data key and to determine a match between the data key and the target data as it is being read from the at least one magnetic storage medium. This device and method can perform a variety of searches on the target data including without limitation exact and approximate match searches, sequence match searches, image match searches and data reduction searches. This device and method may be provided as part of a stand-alone computer system, embodied in a network attached storage device, or can otherwise be provided as part of a computer LAN or WAN. In addition to performing search and data reduction operations, this device may also be used to perform a variety of other processing operations including encryption, decryption, compression, decompression, and combinations thereof.

255 citations

Journal ArticleDOI
TL;DR: One of the key aims of this paper is to present results such that one can perform the relevant set computations using polyhedral algebra and computational geometry software, provided the system is piecewise affine and the constraints are polygonal.
Abstract: This paper presents new results that allow one to compute the set of states that can be robustly steered in a finite number of steps, via state feedback control, to a given target set. The assumptions that are made in this paper are that the system is discrete-time, nonlinear and time-invariant and subject to mixed constraints on the state and input. A persistent disturbance, dependent on the current state and input, acts on the system. Existing results are not able to address state- and input-dependent disturbances and the results in this paper are, therefore, a generalization of previously published results. One of the key aims of this paper is to present results such that one can perform the relevant set computations using polyhedral algebra and computational geometry software, provided the system is piecewise affine and the constraints are polygonal. Existing methods are only applicable to piecewise affine systems that either have no control inputs or no disturbances, whereas the results in this paper remove this limitation. Some simple examples are also given that show that, even if all the relevant sets are convex and the system is linear, convexity of the set of controllable states cannot be guaranteed.

190 citations

Book
30 Oct 2011
TL;DR: This book provides a technically detailed, yet readable, account of the state of the art of block cipher analysis, design, and deployment and provides an overview of some of the most important cryptanalytic methods.
Abstract: Block ciphers encrypt blocks of plaintext, messages, into blocks of ciphertext under the action of a secret key, and the process of encryption is reversed by decryption which uses the same user-supplied key. Block ciphers are fundamental to modern cryptography, in fact they are the most widely used cryptographic primitive useful in their own right, and in the construction of other cryptographic mechanisms. In this book the authors provide a technically detailed, yet readable, account of the state of the art of block cipher analysis, design, and deployment. The authors first describe the most prominent block ciphers and give insights into their design. They then consider the role of the cryptanalyst, the adversary, and provide an overview of some of the most important cryptanalytic methods. The book will be of value to graduate and senior undergraduate students of cryptography and to professionals engaged in cryptographic design. An important feature of the presentation is the authors' exhaustive bibliography of the field, each chapter closing with comprehensive supporting notes.

186 citations