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Matched design method for concatenated trellis-coded modulation

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS communicationS AND computer scienceS 1996年第11期E79A卷 1911-1917页

作者： Wadayama, T Wakasugi, K Kasahara, M Faculty of Computer Science and System Engineering Okayama Prefectural University Soja-shi 719-11 Japan Department of Electronics and Information Science Kyoto Institute of Technology Kyotoshi 606 Japan

A new design method, which is referred to as the matched design method, for concatenated trellis-coded modulation (TCM) is presented. Most of the conventional concatenated TCM employs TCM designed to maximize the minimum squared Euclidean free distance, d(free)(2). With the matched design method, we maximize d(1)(2)(t) instead of d(free)(2), where d(1)(2)(t) is the effective minimum squared Euclidean distance (MSED) when the outer code has a t-error correcting capability. The effective MSED is derived from the Euclidean/Hamming (E/H) joint weight distribution of terminated TCM. We here assume the concatenated TCM whose transmitted symbol corresponds to a symbol of outer code. The new classes of 2-dimensional(2D) and 4-dimensional(4D) codes are found by a computer search. Under the performance measures of the effective MSED or the effective multiplicity, these codes are superior to the conventional codes such as the Ungerboeck's 2D-codes when those are used as an inner code. We disclose an interesting fact that the new class of codes using rate-1/2 encoder is superior to the class of codes using rate-2/3 encoder. This fact implies that the codes using rate-1/2 encoder have two advantages: 1) better overall decoding performance and 2) less decoding complexity.

关键词： trellis-coded modulation concatenated code weight distribution

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Optical Fiber Demultiplexer-Star Coupler Using a Single GRIN-Rod Lens and a Multi-Facet Grating 11

Optical Fiber Demultiplexer-Star Coupler Using a Single GRIN...

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11th Optical Fiber Sensors Conference, OFS 1996

作者： Fukushima, Takehiro Sakamoto, Toyokazu Department of System Engineering Faculty of Computer Science and System Engineering Okayama Prefectural University 111 Kuboki Soja Okayama719-11 Japan

An optical fiber multi-function device using a single GRIN-rod lens and a multi-facet blazed reflection grating is proposed for realizing the functions of both demultiplexing and optical signal distribution. © 19... 详细信息

ISBN: (纸本)0819430447

关键词： Optical fibers

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A 7/spl times/6 optical fiber grating demultiplexer-multiposition switch for 0.64-0.88 /spl mu/m band

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Journal of Lightwave Technology 1996年第5期14卷 867-872页

作者： T. Fukushima T. Sakamoto Department of system Engineering Faculty of Computer Science and System Engineering Okayama Prefectural University Okayama Japan

An optical fiber grating demultiplexer-multiposition switch having seven demultiplexing channels and six position-switching channels is demonstrated. This device consists of a unique fiber array in which 42 output fibers are aligned radially around an input fiber, a single gradient-index (GRIN)-rod lens and a rotatable blazed reflection grating. In this device, seven demultiplexing channels can be switched to six different directions by rotating blazed reflection grating. Therefore, this device can realize total transmission channels of 42. The device had a working band of 0.64-0.88 /spl mu/m, a channel separation of 35-42 nm and a 3 dB band width of 18-22 nm. The deviations of center wavelengths among the switching channels were suppressed less than 3 nm.

关键词： Optical fibers Fiber gratings Optical switches Optical fiber devices Optical filters Demultiplexing Optical films Optical devices Lenses Optical reflection

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A Self-Tuning PID Controller Fused Artificial Neural Networks

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IFAC Proceedings Volumes 1996年第1期29卷 5066-5071页

作者： Toru Yamamoto Masahiro Kaneda Toshitaka Oki Department of Communication Engineering Faculty of Computer Science and Systems Engineering Okayama Prefectural University 111 Kuboki Soja Okayama 719-11 Japan

Recently, neural network techniques have widely used in adaptive and learning control schemes for nonlinear systems. However, generally, it costs a lot of time for learning in the case applied in control systems. Furthermore, the physical meaning of neural networks constructed as a result, is not obvious. In this paper, a design method of self-tuningPID controllers is proposed, which has a fusional structure of self-tuning and neural network schemes. This method enables us to understand a physical meaning of the control parameters, and also to adjust PID gains quickly.

关键词： self-tuning control PID control neural networks intelligent control nonlinear systems

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Performance of Reed-Solomon coded type-1 hybrid ARQ scheme on fading channels

Performance of Reed-Solomon coded type-1 hybrid ARQ scheme o...

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IEEE Conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： H. Tanaka K. Sakakibara Information and Communication Systems Laboratory Toshiba Corporation Japan Faculty of Computer Science and System Engineering Okayama Prefectural University Japan

A Reed-Solomon coded type-1 hybrid ARQ scheme based on a selective-repeat (SR) ARQ with multicopy retransmission is proposed for mobile/personal satellite communication systems of a transmitter and a receiver both with finite buffer. The performance of the proposed scheme on fading channels is analyzed. The basic idea of the strategy is the use of two modes; the SR mode and the multicopy mode. In the latter mode, erroneous blocks stored in the /spl nu/N block transmitter buffer are alternatively retransmitted multiple times when /spl nu/ consecutive retransmissions in the SR mode are received in error, where N denotes round-trip-delay in blocks. Numerical and simulation results for /spl nu/=1 show that the proposed scheme presents better performance than the conventional SR+ST scheme 2 of the 2N block buffer by Miller and Lin (1981).

关键词： Reed-Solomon codes Automatic repeat request Fading Strontium Transmitters Throughput Performance analysis Buffer storage Satellite communication Buffer overflow

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Parallel complexity hierarchies based on PRAMs and DLOGTLME-uniform circuits

Parallel complexity hierarchies based on PRAMs and DLOGTLME-...

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Annual IEEE Conference on Computational Complexity

作者： K. Iwama C. Iwamoto Department of Computer Science and Communication Engineering Kyushu University Fukuoka Japan Faculty of Design kyushu Institute of Design Fukuoka Japan

Unlike the case of logspace-uniform circuits, complexity hierarchies do exist for PRAMs and DLOGTIME-uniform circuits: (i) There exist a constant d and a language L such that L is recognizable in time dT(n) by some PRIORITY CRCW PRAM but is not recognizable in time T(n) by any PRIORITY CRCW PRAM if the number of processors is fixed. (ii) There exist constants c, d and a language L such that L is recognizable by some family of DLOGTIME-uniform circuits of size (Z(n))/sup c/ and depth dT(n) but is not recognizable by any family of DLOGTIME-uniform circuits of size Z(n) and depth T(n) if T(n) is not bounded by O(log n).

关键词： Phase change random access memory Circuits Polynomials computer science

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Design of dielectric multilayer bandpass filters using fundamental thickness of layers

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ELECTRONICS AND communicationS IN JAPAN PART II-ELECTRONICS 1996年第6期79卷 31-42页

作者： Wakabayashi, I Miyauchi, K Faculty of Engineering Science University of Tokyo Tokyo Japan 162 Received his B.E. and M.E. degrees in Electrical Engineering from the Science University of Tokyo in 1974 and 1976 respectively. He joined the Science University of Tokyo as an Instructor of Electrical Engineering in 1976. Since then he was involved in research on measurements of surface topography by using evanescent wave in microwave. Since the end of 1990 he has been involved in research on optical and microwave filters. He is a member of the Society of Applied Physics (Japan) and IEEE. Nonmember Graduated from the University of Tokyo in Electrical Engineering in 1954 and joined NTT the same year. He was appointed as a member of the technical staff department director vice director-general of Research and Development Bureau director of Radio System and Network Laboratory etc. of Electrical Communication Laboratories. During this period he was involved in research development and management of microwave and millimeter wave high-speed digital communication systems satellite communication systems communication satellite on-board equipment (CS-2CS-3N-STAR etc.) submarine optical fiber communication systems mobile communications etc. In 1986 he joined the Science University of Tokyo as a Professor. He received his Ph.D. degree from the University of Tokyo in 1966 and is an IEEE Fellow. He was chairman of the Microwave Research Committee chairman of the Satellite Communications Research Committee chairman of IEEE MTT Tokyo Chapter chairman of Microwave APMC'90 International Symposium Organizing Committee Member of the Radio Science Committee of the Science Council of Japan etc. He received the Paper Award of this Society (two times) Achievement Award Mainichi Industrial Technology Award etc. He is the author ofMicrowave Circuits for Communications Digital Satellite Communications Microwave and Optical Engineering Satellite Communication Networks An Introduction to Communication Systems and other books.

The general design principle of the dielectric multilayer bandpass filters proposed by the authors is applied to the case where only the fundamental thickness of dielectric layers are used. The actual design procedure, layer structure, necessary formulation in the design, conditions, and design examples are presented. Further, with respect to various combinations of the parameters, 900 filters are designed and their characteristics are verified to show the distribution of their design errors. In actual designs, the objectives are third-, fifth-, and seventh-order Butterworth and Chebyshev filters (0.5-dB and 1-db ripples) using SiO2 and TiO2 and the center wavelength of 1.3 mu m. The percentage bandwidths am taken to be up to 10 percent with angles of incidence up to 30 deg with P or S polarizations. It is understood that, when the bandwidth is set to be less than 5 percent or when it is set in the range of 5 to 10 percent, it is possible to achieve designed filters with percentage bandwidth errors below 1 percent and 3 percent, respectively. In all Butterworth filters, the insertion loss at the center wavelength was below 0.04 dB. For the objective ripple in Chebyshev filters set at 0.5 dB, the maximum ripples of all filters distribute within 0.15 to 2 dB while, in the case of l-dB objective ripple, they are in the range from 0.4 to 2.3 dB.

关键词： dielectric multilayer bandpass filters fundamental thickness of dielectric layers Butterworth Chebyshev

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A method for understanding intentions of indirect speech acts in natural language interfaces

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systemS AND computerS IN JAPAN 1996年第1期27卷 77-91页

作者： Mima, H Aoe, J Fuketa, M Hayashi, Y Member Faculty of Engineering The University of Tokushima Tokushima Japan 770 Jun-ichi Aoe received his B.E. and M.E. degrees in Electronic Engineering from the University of Tokushima Tokushima Japan in 1974 and 1976 respectively and his Ph.D. degree in Communication Engineering from the University of Osaka Japan in 1980. Since 1976 he has been with the University of Tokushima. He is currently a Professor in the Department of Information Science and Intelligent Systems at the University of Tokushima. He is the author of about 50 scientific papers. His research interests include computer algorithms in software engineering and natural language processing. Dr. Aoe is editing Computer Algorithms Series of the IEEE Computer Society Press and author of two books: Computer Algorithms-Key Search Strategies in 1991 and String Pattern Matching Strategies in 1994. He received a Best Author Award from the Information Processing Society of Japan in 1993. He is a member of the Association for Computing Machinery the American Association for Artificial Intelligence the Association for Computational Linguistics and the Information Processing Society of Japan the Society for Software Science and Technology the Japanese Society for Artificial Intelligence and the Association for Natural Language Processing of Japan. Nonmember

In an attempt to propose a robust method for understanding natural language (NL) interface commands, a scheme is proposed that infers intentions from an indirect speech-act that does not express users' real intentions explicitly. This method classifies the real intentions of the indirect speech-act into: 1) refusal;2) reversal;3) restriction;4) benefit;and 5) disability. Further, concepts are abstracted for operations, e.g., displaying, moving, and deleting information systems;and constructing the operation knowledge base. This knowledge based comprises operational concepts and the relationships between them. These relationships are assigned the foregoing classifications for intentions. In addition, we construct the knowledge base of objects for the target of operations, e.g., files, figures, strings. This knowledge base contains the relationships: a) antonym;b) exclusive;c) part-of, between the objects;and uses these relations to infer the transitions between the objects. An algorithm is the proposed to infer concepts for operations and concepts for target objects of operations that may represent the user's actual intentions. This proposal scheme was tested with requests on UNIX and a commercially available Japanese Word Processor. The system successfully inferred the intentions for approximately 80 percent of the user's indirect speech-act.

关键词： natural language interface indirect speech act inference of intention

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Proof Method for correctness of refinements of algebraic specification in abstract sequential machine style

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systemS AND computerS IN JAPAN 1996年第5期27卷 25-38页

作者： Okano, K Higashino, T Taniguchi, K Member Faculty of Engineering Science Osaka University Toyonaka Japan 560 Teruo Hipshino received his B.E. M.E.and Ph.D. degrees in Information and Computer Sciences from Osaka University Osaka Japan in 1R9 1981 and 1984 respectively. He joined the Faculty of Osaka University in 1984. Since 1991 he has been an Associate Professor in the Department of Information and Computer Sciences at Osaka University. In 1990 he was a Visiting Researcher of Dept. I.R.O. at University of Montreal Canada. His current research interests include design and analysis of distributed systems specification and verification of communication protocols and formal approach of program design. He is a member of IEEE-CS ACM IEICE of Japan and IPS of Japan.

In this paper, new methods for providing the correctness of refinement among abstract sequential machine style programs are described. The programs are described in algebraic language ASL using some useful notions, i.e., the extended projection and the valid reachability condition for each transition function. These notions allow a designer to refine a given text (program or specification) to a concrete text more freely than the text that does not use such notions. These notions can also enhance the expressive power of the text. On the other hand, these advantages would have lost half their values, if useful methods to prove the correctness of refinement among the texts using them are not found. Thus new methods for proving the correctness of the texts are proposed, and they do not require much proof loads. First, the correctness of refinement among the ASL texts with the extended projection is defined. Second, a method is proposed for proving the correctness of refinement among such texts. Also proposed is a definition of the correctness of refinement among the texts with the valid reachability conditions and a method to prove their correctness. These methods do not require more proof loads than the usual methods for the texts that do not use such notions in the abstract sequential machine style. Therefore, these methods are useful.

关键词： abstract sequential machine ASL language proof algebraic specification

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KERR-EFFECT-INDUCED S-R FLIP-FLOP OPERATION IN AN OPTICAL-FIBER LOOP RESONATOR WITH DOUBLE COUPLERS

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OPTICS LETTERS 1995年第10期20卷 1119-1121页

作者： FUKUSHIMA, T SAKAMOTO, T []Department of System Engineering Faculty of Computer Science System Engineering Okayama Prefectural University 111 Kuboki Soja Okayama 719-11 Japan

We carry out a theoretical analysis of Kerr bistability in a double-coupler optical fiber loop resonator in a case of two coexisting input optical fields, and we propose a set-reset (S-R) flip-flop operation that uses two input ports. We found that in the optimum case set and reset operation can be achieved at relatively low optical input powers.

关键词： Optical fibers Optical fields Optical resonators Phase shift Refractive index Ring resonators

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