A Discrete Event System (DES) is a system that is modeled by a finite automaton. A Cooperating Discrete Event System (CDES) is a distributed system which consists of several local DESs which are synchronized with each other to accomplish its own goal. This paper describes the automatic synthesis of a CDES from a modular temporal logic specification. First, MPTS (Modular Practical Temporal Specification language) is proposed in which the new features (modular structure and domain specification) are appended to temporal logic. To overcome the "state explosion problem", which occurs in generating a global automaton in former synthesis methods using temporal logic, a compositional synthesis is proposed where automata are reduced at every composition step.

It is important to develop methods of measuring radiated electromagnetic interference level that will produce identical results at all measuring locations. We have considered a number of problems which prevent the achievement of identical results, and proposed some solutions. However, agreement of measurement values adequate for practical purposes has not been achieved. After our successive studies, we finally became aware that there is a causal relationship with changes in the line-to-ground impedance of the power supply. It is presumed that power cables of AC-powered devices operate as antenna elements that produce emission. Thus changes in the power line-to-ground impedance cause variations in the radiation efficiency to produce a different EMI level. We therefore made plans to measure the values of line-to-ground impedance at the AC power outlet for the frequency range of 100kHz to 500MHz at various locations where measurements are made of EMI from EUT (Equipment Under Test). The impedance varies greatly between 6ohms and 2 k-ohm, not only according to the frequency, but also according to the measurement location. In such cases, the EMI level shows a different value even with the same EUT, and it usually increases-especially for vertical polarization. We have developed a new type of LISN (Line Impedance Stabilization Network or Artificial Mains Network) to stabilize the power line-to-ground impedance to get consistent measurement conditions. The LISN consists of feed-through capacitors and an disk type RF resistor. The measurements confirm the consistency in the impedance value which is maintained at 50 ohms in the frequency range from 1MHz to 500MHz. Thus the newly developed LISN improves consistency of measurement values at all locations, while it was difficult to obtain good correlation before employing the LISN. We feel confident that incorporation of the method discussed here in the pertinent technical standards of EMI measurements, such as CISPR, would lead to a major improvement in getting consistent measurements values.

A new model for a computer simulation of RF capacitive type hyperthermia has been developed by taking account of the following points. Blood flow is usually determined by many physiological parameters, but is regarded as a function of only blood temperature under some conditions. The temperature dependence of blood flow of tumors and normal tissues is assumed by referring the data obtained by Song et al. and Tanaka. The blood temperature which is elevated by externally applied power significantly affects temperatures of the body and the tumors. The transport of heat from the body surface is studied by considering air convection. These points are examined by experiments on a computer with simple phantom models and real patients. The results of simulation on the patient have shown a good agreement with clinical inspection based on CT images and a temperature of the stomach.

We present schemes for disseminating information in the n-dimensional hypercube with some faulty nodes/edges. If each processor can send a message to t neighbors at each round, and if the number of faulty nodes/edges is k(kn), then this scheme will broadcast information from any source to all destinations within any consecutive n+[(k+l)/t] rounds. We also discuss the case where the number of faulty nodes is not less than n.

Suppose that there are terminals on two concentric circles, Cin and Cout, with Cin inside of Cout. We are given a set of nets each of which consists of a terminal on Cin and a terminal on Cout. The routing area is the annular region between the two circles. In this paper, we present an O(nk-1) time algorithm for testing whether the given net set is k-layer routable without vias, where k2 and n is the number of nets.

In this paper, we propose a new algorithm for the problem of floorplanning of the mixed design of macro and standard cells. The proposed algorithm which is based on partitioning and slicing approach, uses a modified min-cut bipartitioning heuristic. The heuristic bipartitions a block of a mixture of macro and standard cells to minimize the netcut, which are the number of nets connecting both sub-blocks, with size constraints. A sub-block is a resulting descendant block. Before starting the bipartitioning of the block, the macro cell with the longest side in the block is selected first. Using edges of the selected macro cell, bipartitionings are performed twice fixing the location of the macro cell on one of 4 corners of the block with its rotation and reflection. Bipartitioning of blocks is repeated until each block has either a macro cell or standard cells without macro cells. As a result of bipartitioning, a slicing tree is constructed. Using the proposed floorplan algorithm, we developed an automatic placement and routing tool, Cell Designer, for the mixed design of macro and standard cells. According to the floorplanner, macro cells are placed and standard cells are grouped into standard cell blocks. Standard cells are placed and routed within estimated area of block using conventional tools. They form a fixed-shaped block like a macro cell. Interconnections between the two adjacent blocks are performed with a conventional channel router. The channels and the order of channel routing are determined following the hierarchy of the slicing tree. Cell Designer has a dedicated graphics editor to provide interactive services to users. Experimental results on well-known benchmark data are shown.

In this paper we review the recent progress and basic technology of vertical cavity surface emitting lasers together with related parallel surface operating optical devices. First, the concept of surface emitting lasers is presented, and then currently developed device technologies will be reviewed. We will feature several technical issues, such as multi-layer structures, 2-dimensional arrays, photonic integration, etc. Lastly, future prospects for parallel lightwave systems will be discussed.

There have been several studies related to a reduction of the amount of computational resources used by Turing machines. As consequences, Linear speed-up theorem", tape compression theorem" and reversal reduction theorem" have been obtained. In this paper, we discuss a leaf reduction theorem on alternating Turing machines. Recently, the result that one can reduce the number of leaves by a constant factor without increasing the space complexity was shown for space- and leaf-bounded alternating Turing machines. We show that for time- and leaf-bounded alternating Turing machines, the number of leaves can be reduced by a constant factor without increasing time used by the machine. Therefore, our result says that a constant factor on the leaf complexity does not affect the power of time- and leaf-bounded alternating Turing machines.

Circuit complexity of a Boolean function is defined to be the minimum number of gates in circuits computing the function. In general, the circuit complexity is established by deriving two types of bounds on the complexity. On one hand, an upper bound is derived by showing a circuit, of the size given by the bound, to compute a function. On the other hand, a lower bound is established by proving that a function can not be computed by any circuit of the size. There has been much success in obtaining good upper bounds, while in spite of much efforts few progress has been made toward establishing strong lower bounds. In this paper, after surveying general results concerning circuit complexity for Boolean functions, we explain recent results about lower bounds, focusing on the method of approximation.

Suppose that there are terminals on two concentric circles Cin and Cout, with Cin inside of Cout. A set of two-terminal nets is given and the routing area is the annular region between the two circles. In this paper, we present an O(n2) time algorithm for testing whether the given net set is two-layer routable, where n is the number of nets. Applying this algorithm repeatedly, we can find, in O(n3) time, a maximal subset of nets which is two-layer routable.

We describe two information disseminating schemes, t-disseminate and t-Rdisseminate in a computer network with N processors, where each processor can send a message to t-directions at each round. If no processors have failed, these schemes are time optimal. When at most t processors have failed, for t1 and t2 any of these schemes can broadcast information within any consecutive logt+1N2 rounds, and for an arbitrary t they can broadcast information within any consecutive logt+1N3 rounds.

We review the role of optics in interconnects, analog processing, neural networks, and digital computing. The properties of low interference, massively parallel interconnections, and very high data rates promise extremely high performance for optical information processing systems.

We review the role of optics in interconnects, analog processing, neural networks, and digital computing. The properties of low interference, massively parallel interconnections, and very high data rates promise extremely high performance for optical information processing systems.

In this paper we review the recent progress and basic technology of vertical cavity surface emitting lasers together with related parallel surface operating optical devices. First, the concept of surface emitting lasers is presented, and then currently developed device technologies will be reviewed. We will feature several technical issues, such as multi-layer structures, 2-dimensional arrays, photonic integration, etc. Lastly, future prospects for parallel lightwave systems will be discussed.

The characteristics of a LiNbO3 light modulator using the resonant YBa2Cu3Oy superconducting electrode were studied on the basis of the calculated results of surface resistances and transmission losses. The two-fluid model and the conventional transmission theory were used for the calculations. It was found that the modulation depth of this modulator using the YBCO electrode at 77 K was 7.5 times that using the Al electrode at room temperature. The drive voltage for the phase modulation of π radians was estimated to be a very low value of 2.3 V.

We studied transient fields on a perfectly conducting sphere excited by a half sine pulse wave and examined the Poynting vectors, the energy densities and the energy velocities of the creeping waves. We used FILT (Fast Inversion of Laplace Transform) method for transient analysis. We compared the amplitudes of the creeping wave with that of steady state high frequency approximation obtained by the Watson transformation. The main results are: (1) We confirmed in the transient response that the pulse propagates clockwise and counterclockwise along the geodesic circumference. (2) In the transient electromagnetic field observed in the E-plane we can recognize creeping waves clearly. (3) The existence of creeping waves is not clear in the H-plane. (4) The pulse wave propagation on the sphere is seen more clearly from the Poynting vectors and the energy densities than the field components. (5) The energy velocity of the wave front is equal to the light velocity as should be. The energy velocity of the wave body becomes smaller with the passage of time. (6) The amplitude of the creeping wave for a beat pulse and the amplitude obtained by the Watson transform for mono spectrum agree in the order of relative error below 25%.

We study the computational power of PC=P. We give a characterization of the class via single Turing machines. Based on the characterization, we give combinatorial problems that are Pm-complete for the class.

The characteristics of a LiNbO3 light modulafor using the resonant YBa2Cu3Oy superconducting electrode were studied on the basis of the calculated results of surface resistances and transmission losses. The two-fluid model and the conventional transmission theory were used for the calculations. It was found that the modulation depth of this modulator using the YBCO electrode at 77 K was 7.5 times that using the Al electrode at room temperature. The drive voltage for the phase modulation of π radians was estimated to be a very low value of 2.3 V.