In this paper we describe the pipeline design and enhanced hardware for fast message handling in a RICA-1 processor, a processing element (PE) in the RWC-1 multiprocessor. The RWC-1 is based on the reduced inter-processor communication architecture (RICA), in which communications are combined with computation in the processor pipeline. The pipeline is enhanced with hardware mechanisms to support fine-grain parallel execution. The data paths of the RICA-1 super-scalar processor are commonly used for communication as well as instruction execution to minimize its implementation cost. A 128-PE system has been built on January 1998, and it is currently used for hardware debugging, software development and performance evaluation.

In this study, a coupled chaotic circuits network is realized by real circuit elements. By using a simple circuit converting generating spatial patterns to digital signal, irregular self-switching phenomenon of the appearing patterns can be observed as real physical phenomenon.

Recent technologies of organic film devices are reviewed. New technologies of fabrication and characterization of organic thin films, electro-mechanical conversion materials, and applications for electrical and optical devices are discussed. In this review paper, especially organic light emitting diodes, tunneling junctions using polyimide Langmuir-Blodgett films, tunneling spectroscopy and high-density recording, plastic actuators using conducting polymers, molecular self-assembly process for fabricating organic thin film devices are reviewed.

For people with serious disability, it is most significant to be able to use the same communication methods, for instance a telephone and an electronic mail system (e-mail), as ordinary people do in order to get a normal life and communicate with other people for leading a social life. In particular, having communications access to an e-mail is a very effective method of communication that enables them to convey their intention to other people directly while at the same time keep their privacy. However, it takes them much time and effort to input an e-mail text on the computer. They also need much support by their attendants. From this point of view, we propose a multi-modal communication system that is composed of a voice recognizer, a pointing device, and a text composer. This system intend to improve the man-machine interface for people with physical disability. In this system, our voice recognition technology plays a key role in providing a good interface between disabled people and the personal computer. When generating e-mail contents, users access the database containing user keywords, and the guidance menu from which they select the appropriate word by voice. Our experimental results suggest that this communication system improves not only the time efficiency of text composition but also the readiness of disabled people to communicate with other people. In addition, our disabled subject on this paper is not able to move his body, legs and hands due to suffer from muscular dystrophy. And he is able to move only his fingers and speak command words with the assistance of a respirator.

The switch-block architecture of FPGAs is discussed to see a good balance between programmable-switch resources and routability. For the purpose, FPGAs are assumed to have certain extremal structures, whose switch-blocks consist of parallel or complete switch-sets where a switch-set is a set of switches between two sides of the switch-block. A polynomial time detailed-routing algorithm for a given global-routing is presented if the switch-block consists of two or less parallel switch-sets or three that form a cycle. For other FPGAs, the corresponding decision problem is proved to be -complete. A best compromise between switch resources and routability is offered.

Many image-processing techniques are based on texture features or gradation features of the image. However, Landsat images are complex; they also include physical features of reflection radiation and heat radiation from land cover. In this paper, we describe a method of constructing a super-resolution image of Band 6 of the Landsat TM sensor, oriented to analysis of an agricultural area, by combining information (texture features, gradation features, physical features) from other bands. In this method, a knowledge-based hierarchical classifier is first used to identify land cover in each pixel and then the least-squares approach is applied to estimate the mean temperature of each type of land cover. By reassigning the mean temperature to each pixel, a finer spatial resolution is obtained in Band 6. Computational results show the efficiency of this method.

In this paper we consider a parallel and distributed computation of genetic algorithms on loosely-coupled multiprocessor systems. Loosely-coupled ones are more suitable for massively parallel processing and also more easily VLSI implementation than tightly-coupled ones. However, communication overhead on parallel processing is more serious for loosely-coupled ones. We propose in this paper a parallel and distributed execution method of genetic algorithm on loosely-coupled multiprocessor systems of fixed network topologies in which each processor element carries out genetic operations on its own chromosome set and communicates with only the neighbors in order to save communication overhead. We evaluate the proposed method on the multiprocessor systems with ring, torus, and hypercube topologies for benchmark problem instances. From the results, we find that the ring topology is more suitable for the proposed parallel and distributed execution since variety of chromosomes in the ring is kept much more than that in the others. Moreover, we also propose a new network topology called cone which is a hierarchical connection of ring topologies. We show its effectiveness by experimental evaluation.

We introduce a subclass of context-free languages, called pure context-free (PCF) languages, which is generated by context-free grammars with only one type of symbol (i. e. , terminals and nonterminals are not distinguished), and consider the problem of identifying paralleled even monogenic pure context-free (pem-PCF) languages, PCF languages with restricted and enhanced features, from positive data only. In this paper we show that the ploblem of identifying the class of pem-PCF languages is reduced to the ploblem of identifying the class of monogenic PCF (mono-PCF), by decomposing each string of pem-PCF languages. Then, with its result, we show that the class of pem-PCF languages is polynomial time identifiable in the limit from positive data. Further, we refer to properties of its identification algorithm.

As expert system technology gains wider acceptance in digital system design, the need to build and maintain a large scale knowledge base will assume greater importance. However, how to build a correct and efficient rule base is even a hard part in the knowledge-based system development. In this paper, we develop FARHDL (Frame-And-Rule-based Hardware Description Language) to form a knowledge base. The FARHDL is simple but powerful to specify the hardware requirements and can be directly simulated by PROLOG. Through the knowledge base transformed from FARHDL, a formal method can be developed to design, implement, and validate the digital hardware systems. Furthermore, behavioral properties, anomaly properties, structural properties, and timing properties are applied to analyze the requirements specification. The purposes of those properties are used to detect explicit/implicit incorrect specification clauses and to capture some desired requirements, such as completeness and consistency. Finally, the analysis results can be a useful tool for finding obscure problems in tricky digital system designs and can also aid in the development of formal specifications.

In this paper, we study bifurcations of equilibrium points and periodic solutions observed in a resistively coupled oscillator with voltage ports. We classify equilibrium points and periodic solutions into four and eight different types, respectively, according to their symmetrical properties. By calculating D-type of branching sets (symmetry-breaking bifurcations) of equilibrium points and periodic solutions, we show that all types of equilibrium points and periodic solutions are systematically found. Possible oscillations in two coupled oscillators are presented by calculating Hopf bifurcation sets of equilibrium points. A parameter region in which chaotic oscillations exist is also shown by obtaining a cascade of period-doubling bifurcation sets.

This paper proposes a secure electronic sealed-bid auction protocol (SEAP) that provides an auction service on the Internet by combining three providers: an auction service provider, a key service provider, and a time service provider. The SEAP uses public key cryptography and the concept of a time-key certificate. The most important property of this protocol is that time-dependent security requirements can be strictly satisfied. The SEAP satisfies the following nine security requirements: (a) no one can deny having made a bid; (b) the protocol should be secure against malicious acts; (c) no bidder can act for another bidder; (d) no one can know who else is bidding until the time comes for the bids to be opened; (e) no one can discover the contents of any of the bids until the time comes for the bids to be opened; (f) the successful bid must have been submitted before the bidding deadline; (g) all bidders can verify that the auction policy has been correctly implemented; (h) the successful bidder can be identified without being required to make himself or herself known; and (i) the bidding contents cannot be altered. The protocol consists of three subprotocols: the Registration Subprotocol, the Bidding Subprotocol, and the Auction Subprotocol. The protocol parameters and algorithm are described in detail.

Fiat-Shamir's identification and signature scheme is efficient as well as provably secure, but it has a problem in that the transmitted information size and memory size cannot simultaneously be small. This paper proposes an identification and signature scheme which overcomes this problem. Our scheme is based on the difficulty of extracting theL-th roots modn (e. g.L=2 1020) when the factors ofnare unknown. We prove that the sequential version of our scheme is a zero knowledge interactive proof system and our parallel version reveals no transferable information if the factoring is difficult. The speed of our scheme's typical implementation is at least one order of magnitude faster than that of the RSA scheme and is relatively slow in comparison with that of the Fiat-Shamir scheme.

In this paper, we propose a new type of authentication system, one-time zero-knowledge authentication system. Informally speaking, in this authentication system, double usage of the same authentication is prevented. Based on these one-time zero-knowledge authentication systems, we propose a new untraceable electronic cash scheme satisfying both untraceability and unreusablity. This scheme overcomes the problems of the previous scheme proposed by Chaum, Fiat and Naor through its greater efficiency and provable security under reasonable cryptographic assumptions. We also propose a scheme, transferable untraceable electronic cash scheme, satisfying transferability as well as the above two criteria. Moreover, we also propose a new type of electronic cash, untraceable electronic coupon ticket, in which the value of one piece of the electronic cash can be subdivided into many pieces.

This paper proposes high-speed similitude retrieval schemes for a viewpoint-based similarity discrimination system (VB-SDS) and presents analytical and experimental performance evaluations. The VB-SDS, which contains a huge set of semantic definitions of commonly used words and computes semantic similarity between any two words under a certain viewpoint, promises to be a very important module in analogical and case-based reasoning systems that provide solutions under uncertainty. By computing and comparing similarities for all words contained in the system, the most similar word for a given word can be retrieved under a given viewpoint. However, the time this consumes makes the VB-SDS unsuitable for inference systems. The proposed schemes reduce search space based on the upper bound of a similarity calculation function to increase retrieval speed. An analytical evaluation shows the schemes can achieve a thousand-fold speedup and confirmed through experimental results for a VB-SDS containing about 40,000 words.

A numerical method is presented for calculating transverse and non-transverse (or tangent) types of homoclinic points of a two-dimensional noninvertible map having an invariant set that reduces to a one-dimensional noninvertible map. To illustrate bifurcation diagrams of homoclinic points and transitions of chaotic states near the bifurcation parameter values, three systems including coupled chaotic maps are studied.

A new multiple-valued current-mode (MVCM) integrated circuit using a switched current-source control technique is proposed for a 1.5 V-supply high-speed arithmetic circuit with low-power dissipation. The use of a differential logic circuit (DLC) with a pair of dual-rail inputs makes the input voltage swing small, which results in a high driving capability at a lower supply voltage, while having large static power dissipation. In the proposed DLC using a switched current control technique, the static power dissipation can be greatly reduced because current sources in non-active circuit blocks are turned off. Since the gate of each current source is directly controlled by using a multiphase clock whose technique has been already used in dynamic circuit design, no additional transistors are required for currentsource control. As a typical example of arithmetic circuits, a new 1.5 V-supply 5454-bit multiplier based on a 0.8µm standard CMOS technology is also designed. Its performance is about 1.3 times faster than that of a binary fastest multiplier under the normalized power dissipation. A prototype chip is also fabricated to confirm the basic operation of the proposed MVCM integrated circuit.

In this study, we show how changing a frequency in one of N chaotic circuits coupled by a resistor effects our system by means of both circuit experiment and computer calculation. In these N chaotic circuits, N-1 circuits are completely identical, and the remaining one has altered the value of the oscillation frequency. It is found that for the case of N = 3 when a value of a coupling resistor is gradually increased, only one circuit with different frequency exhibits bifurcation phenomena including inverse period-doubling bifurcation, and for larger value of coupling resistor, the chaotic circuit with different frequency suddenly stops oscillating and the remaining two chaotic circuits exhibit completely anti-phase synchronization.

Characteristics of a distortion, gain and efficiency of a power amplifier grow worse extremely by different phases of the load reflection coefficient when load impedances of the power amplifier are far from 50 Ω. It was found that the value of the distortion, gain and efficiency showed the tradeoff behavior when the phase of the reflection coefficient was different in 180 degrees. Therefore we have proposed new two- and four-parallel unit power amplifiers combined in 90 degree and 45 degree different phases each in order to accomplish low distortion and high efficiency in wide range of load impedances without an isolator. We studied the power amplifiers by simulation based on experiments and realized an amplifier in that adjacent channel leakage power of π/4-DQPSK modulation (for Japan's digital cellular system) is less than -45 dBc and efficiency is over 45% in range of load VSWR less than 3.

In this paper a cyclic place-timed controlled marked graph (PTCMG), which is an extended class of a cyclic controlled marked graph (CMG), is presented as a model of discrete event systems (DESs). In a PTCMG, time constraints are attached to places instead of transitions. The time required for a marked place to be marked again is represented in terms of time constraints attached to places. The times required for an unmarked place to be marked under various controls, are calculated. The necessary and sufficient condition for a current marking to be in the admissible marking set with respect to the given forbidden condition is provided, as is the necessary and sufficient condition for a current marking to be out of the admissible marking set with respect to the forbidden condition in one transition. A maximally permissive state feedback control is synthesized in a PTCMG to guarantee a larger admissible marking set than a CMG for most forbidden state problems. Practical applications are illustrated for a railroad crossing problem and an automated guided vehicle (AGV) coordination problem in a flexible manufacturing facility.

This paper presents a theory based on combined differential- and common-mode propagation for crosstalk and transient analysis of pairs of asymmetric coupled interconnects with arbitrary time-invariant linear termination circuits. Time-domain solutions are obtained by an exact numerical inversion of Laplace transform (NILT). Two example circuits (coupled coplanar stripline and microstrip structures) are studied to examine the accuracy and efficiency of the present method.