The meaning of analogical reasoning in locally stratified logic programs are described by generalized stable model (GSM) semantics. Although studies on the theoretical aspects of analogical reasoning have recently been on the increase, there have been few attempts to give declarative semantics for analogical reasoning. This paper takes notice of the fact that GSM semantics gives meaning to the effect that the negated predicates represent exceptional cases. We define predicates that denote unusual cases regarding analogical reasoning; for example, ab(x)p(x)g(x), where p(s), q(s), p(t) are given. We also add rules with negated occurrences of such predicates into the original program. In this way, analogical models for original programs are given in the form of GSMs of extended programs. A proof procedure for this semantics is presented. The main objective of this paper is not to construct a practical analogical reasoning system, but rather to present a framework for analyzing characteristics of analogical reasoning.

Spread spectrum (SS) communication systems have been studied and developed for commercial applications such as mobile communications, consumer communications and so on. The reason is that SS communication systems have various characteristic features, such as, robust immunity to interference and jamming, achieving privacy in communication and random access capability (spread spectrum multiple access: SSMA). The performance of the systems, mainly, depends on modulation method of spreading the spectrum. This paper introduces recent several methods of modulation in SS communication systems. First, direct-sequence (DS), which is a fundamental modulation in SS communication system, and M-ary/SSMA, which can increase the number of multiple access users, are described. For increasing the data rate per user, parallel SS, parallel combinatory SS and a code division multiplex using orthogonal Manchester coded M-sequences are introduced. Second, frequency hopping (FH), in which the spectrum of signal is spread by hopping carrier frequency, and related systems are shown. Finally, from a viewpoint of communication theory, spectral efficiency (i.e., data rate the number of multiple access users/bandwidth) of systems relating spreading codes are discussed. As a result, maximum spectral efficiency can be obtained by appropriate spreading factor for each spreading code.

By close analogy of annealing for solids, we devise a new algorithm, called APS, for the time evolution of both the state and the synapses of the Hopfield's neural network. Through constrainedly random perturbation of the synapses of the network, the evolution of the state will ignore the tremendous number of small minima and reach a good minimum. The synapses resemble the microstructure of a network. This new algorithm anneals the microstructure of the network through a thermal controlled process. And the algorithm allows us to obtain a good minimum of the Hopfield's model efficiently. We show the potential of this approach for optimization problems by applying it to the will-known traveling salesman problem. The performance of this new algorithm has been supported by many computer simulations.

New methods are needed for accessing very large information services. This paper proposes the use of a user model neural network to allow better access to a news service. The network is constructed on the basis of articles read, and articles marked as rejected. It adapts over time to better represent the user's interests and rank the articles supplied by the news service. Using an augmented keyword search we can also search for articles using keywords in conjunction with the user model neural network. Trials of the system in a USENET news environment show promising results for the use of this approach in information retrieval.

Optical couplers which are composed of three channel waveguides arranged two-dimensionally are investigated numerically. The mode-matching method that matches the boundary conditions in the sense of least squares is applied to this problem, using the hybrid-modal representation. The precise numerical results of the dispersion relations and field distributions are presented for the lowest three modes near the cutoff. The arrangement of three waveguides can be optimized so as to satisfy the condition for maximum power-transfer efficiency.

Serious failures of the latest electronic equipments occur easily due to electrostatic discharge (ESD) , which can be caused frequently by the electrification phenomena of human-body walking on the floor. The number of the above damaging incidents has significantly been increasing with an increased use of integrated semiconductor elements with lower operation power. The most effective measures against the ESD consist in preventive ones, which are to obtain dynamic behaviors of the electric charge before the ESD happens, thereby preventing the charge accumulation. From this point of view, this paper describes new approaches for measurement of the static electricity directed toward preventing the ESD. First, a two-dimensional measurement method for visualizing charge distributions is described. This principle is based on visualizing the potential distribution induced in the array electrodes from the electrostatic fields. For showing usefulness of the visualization measurement, a prototype was built and attempts were made on the visualizations for the static electricity distributions of charged bodies. Second, a potential calculation of the human body charged by walking on the floor is described. A model was shown for analyzing the human-body potential on the floor, and the theoretical equation for describing the potential attenuation process was derived in the closed form in the Laplacian transformation domain. In order to obtain the typical half-life of the human-body potential, numerical computations were performed using a reverse Laplacian transformation. The experiments were also conducted for confirming the validity of the computed results. Finally, a new method is described for estimating dynamic behaviors of the occurrence charges of the human body electrified by walking-motions. Statistical measurements of the charges and potentials were made for the fundamental walking-motions specified here. The pace transitions of the potentials due to continuous walking and stepping were also measured and their results were explained from the electrification properties for the fundamental walking-motions.

One performance limitation of the "Leaky Bucket algorithm" for usage parameter control and traffic management in Asynchronous Transfer Mode (ATM) networks is analyzed. Simulation results show that the conventional statistical bandwidth allocation method, which uses the most bursty pattern permitted by the Leaky Bucket algorithm, can not guarantee the QOS of established Virtual Channels/Paths (VC/VP). As a result, the VC/VP bandwidth allocation method based on the Leaky Bucket algorithm is proven to be unsatisfactory.