One of the most interesting and most analyzed aspects of the CPU design is the instruction set design. How many and which operations to be provided by hardware is one of the most fundamental issues relaing to the instruction set design. This paper describes a novel method that formulates the instruction set design of ASIP (an Application Specific Integrated Processor) using a combinatorial appoach. Starting with the whole set of all possible candidata instructions that represesnt a given application domain, this approach selects a subset that maximizes the performance under the constraints of chip area, power consumption, and functional module sharing relation among operations. This leads to the efficient implementation of the selected instructions. A branch-and-bound algorithm is used to solve this combinatorial optimization problem. This approach selects the most important instructions for a given application as well as optimizing the hardware resources that implement the selected instructions. This approach also enables designers to predict the perfomance of their design before implementing them, which is a quite important feature for producing a quality design in reasonable time.

A wavelength-insensitive reflector is demonstrated with a fibre loop which has an asymmetry in the constituent coupler. The reflector is made by thinning one of two identical fibres. The reflected power is more than 0.6 dB (87%) over the wavelength region of 1.2-1.35 µm and 1.42-1.65 µm. The transmitted power is less than 30 dB in the 1.23-1.63 µm region and less than 40 dB at 1.3 and 1.55 µm.

A cylindrical active phased array antenna was developed. A primary surveillance radar (PSR) antenna and a secondary surveillance radar (SSR) antenna are integrated conformally. The PSR antenna employs two-dimensional electronic beam scanning. The SSR antenna employs electronic beam scanning in azimuth. Advantages of this antenna, design architecture employed and measured characteristics are described.

A fully focused Synthetic Aperture Radar (SAR) image can be obtained only if the raw data processing procedure takes into account the space-variance of the SAR system transfer function. This paper presents a nonconventional Fast Fourier Transform (FFT) algorithm which allows an efficient compensation of the space-variant effect. It is specially designed for the SAR data of the Japanese Earth Resources Satellite (JERS-1) but can be extended to different cases.

In this paper we present a method to generate test sequences for stuck-at faults in sequential circuits which have distinguishing sequences. Since the circuit may have no distinguishing sequence, we use two design techniques for circuits which have distinguishing sequences. One is at state transition level and the other is at gate level. In our proposed method complete test sequence can be generated. The sequence consists of test vectors for the combinational part of the circuit, distinguishing sequences and transition sequences. The test vectors, which are generated by a combinational test generator, cause faulty staes or faulty output responses for a fault, and disinguishing sequences identify the differences between faulty states and fault free states. Transition sequences are necessary to make the state in the combinational vectors. And the distinguishing sequence and the transition sequence are used in the initializing sequence. Some techniques for shortening the test sequence is also proposed. The basic ideas of the techniques are to use a short initializing sequence and to find the order in concatenating sequences. But fault simulation is conducted so as not to miss any faults. The initializing sequence is obtained by using a distinguishing sequence. The efficiency of our method is shown in the experimental results for benchmark circuits.

We describe K-NET, a support system for development of sequence control programs. The K-NET description model is based on the colored Petri net and timed Petri net. K-NET concisely expresses sequence control flow including synchronization, interlock and concurrence, and provides high-level data processing by being combined with a conventional procedural language. K-NET has an editor, simulator, generator, reporter and monitor to support the control program development procedure ranging from basic and detail design to programming and testing. We have added a new function to K-NET so it assists development of control programs for programmable controllers, and have applied it to an automatic bolt supplying system. The operation results are satisfactory.

This paper first proposes a fast fingerprint identification method based on a weighted-mean of binary image, and further investigates optimization of the weights. The proposed method uses less computer memory than the conventional pattern matching method, and takes less computation time than both the feature extraction method and the pattern matching method. It is particularly effective on the fingerprints with a small angle of inclination. In order to improve the identification precision of the proposed basic method, three schemes of modifying the proposed basic method are also proposed. The performance of the proposed basic method and its modified schemes is evaluated by theoretical analysis and computer experiment using the fingerprint images recorded from a fingerprint read-in device. The numerical results showed that the proposed method using the modified schemes can improve both the true acceptance rate and the false rejection rate with less memory and complexity in comparison with the conventional pattern matching method and the feature extraction method.

This paper tends to analyze the trends of the research in logic synthesis. The first part is devoted to an expertise of the efficiency of factorization methods developed during the last decade and to the proposal of dedicated methods for complex logic blocks. The second part shows the importance of Binary Decision Diagrams as representation of Boolean functions. Their use in the technology mapping phase of multiplexor-based FPGAs in an industrial tool is taken as illustration.

A complete analysis for the quantization noises and the reconstruction noises of the wavelet pyramid coding system is given. It is shown that in the (orthonormal) wavelet image coding system, there exists a simple and exact formula to compute the reconstruction mean-square-error (MSE) for any kind of quantization errors. Based on the noise analysis, an optimal bit allocation scheme which minimizes the system reconstruction distortion at a given rate is developed. The reconstruction distortion of a wavelet pyramid system is proved to be directly proportional to 2-2, where is a given bit rate. It is shown that, when the optimal bit allocation scheme is adopted, the reconstruction noises can be approximated to white noises. Particularly, it is shown that with only one known quantization MSE of a wavelet decomposition at any layer of the wavelet pyramid, all of the reconstruction MSE's and the quantization MSE's of the coding system can be easily calculated. When uniform quantizers are used, it is shown that at two successive layers of the wavelet pyramid, the optimal quantization step size is a half of its predecessor, which coincides with the resolution version of the wavelet pyramid decomposition. A comparison between wavelet-based image coding and some well-known traditional image coding methods is made by simulations, and the reasons why the wavelet-based image coding is superior to the traditional image coding are explained.

Corresponding to the development of B-ISDN, integrated services for data, voice, etc. are imperatively required for the so called third generation wireless communication networks. In this paper, I-ISMA (Idle Signal Multiple Access for Integrated services) is proposed to transmit integrated voice and data traffic from dispersed terminals to a base station. In the system, data packets and the first packets of talkspurts of conversational speeches are transmitted using ISMA protocol over a shared channel while subsequent packets of talkspurts are sent with time reservation technique. The channel capacity of I-ISMA is evaluated and compared with that of PRMA. The region in which I-ISMA has larger capacity than PRMA is figured out. Generally speaking, I-ISMA has larger capacity than PRMA when the duration for transmitting and detecting an idle signal is not too long and the channel is not too congested by the reserved voice transmissions. When we concern real time voice transmission, delay is one of the most important performance measures. Only is a qualitative discussion on delay performance given here. The quantitative evaluation is obtained by the dynamic analysis in our succeeding paper.

This paper considers the problem of finding a largest common subgraph of graphs, which is an important problem in chemical synthesis. It is known that the problem is NP-hard even if graphs are restricted to planar graphs of vertex degree at most three. By the way, a graph is called an almost tree if E(B)V(B)+ K holds for every block B where K is a constant. In this paper, a polynomial time algorithm for finding a largest common subgraph of two graphs which are connected, almost trees and of bounded vertex degree. The algorithm is an extension of a subtree isomorphism algorithm which is based on dynamic programming. Moreover, it is shown that the degree bound is essential. That is, the problem of finding a largest common subgraph of two connected almost trees is proved to be NP-hard for any K0 if degree is not bounded. The three dimensional matching problem, a well known NP-complete problem, is reduced to the problem.

In this paper, a definitce relation between the TSP's optimal solution and the attracting region in the parameters space of TSP's energy function is discovered. An many attracting region relating to the global optimal solution for TSP is founded. Then a neural network algorithm with the optimized parameters by using Orthogonal Array Table Method is proposed and used to solve the Travelling Salesman Problem (TSP) for 30, 31 and 300 cities and Map-coloring Problem (MCP). These results are very satisfactory.

A new method by which images are coded with predictable and controllable subjective picture quality in the minimum cost of bit rate is developed. By using wavelet transform, the original image is decomposed into a set of subimages with different frequency channels and resolutions. By utilizing human contrast sensitivity, each decomposed subimage is treated according to its contribution to the total visual quality and to the bit rate. A relationship between physical errors (mainly quantization errors) incurred in the orthonormal wavelet image coding system and the subjective picture quality quantified as the mean opinion score (MOS) is established. Instred of using the traditional optimum bit allocation scheme which minimizes a distortion cost function under the constraint of a given bit rate, we develop an "optimum visually weighted noise power allocation" (OVNA) scheme which emphasizes the satisfying of a desired subjective picture quality in the minumum cost of bit rate. The proposed method enables us to predict and control the picture quality before the reconstruction and to compress images with desired subjective picture quality in the minimum bit rate.

Fiber-optic passive double star (PDS) network is described as an access network for microcellular radio communication systems. The intrinsic characteristics of the PDS network, reduction in the optical fiber count and flexible access capability, are examined. A unit cell structure is introduced which enables the PDS network to be effectively incorporated into the access portion of microcellular radio communication systems. The reduced total fiber length in the unit cell structure based on the PDS network is discussed in comparison with the conventional architecture. Calculations show that there is an optimum splitting ratio that minimizes the total fiber length. When the microcell radius and service area radius are 100m and 10km, respectively, the total fiber length of the PDS network is reduced to only about 9% of that of the conventional single star (SS) network for a splitting ratio of 34. Resource sharing and handover between microcells in a unit cell are performed by using the dynamic channel allocation function of the PDS system. Substantial performance improvement for loaded traffic can be obtained by resource sharing. When the splitting ratio is 32, the available traffic of a base station (BS) increases from 0.9 [erl/BS] to 3.4 [erl/BS] by adopting dynamic channel allocation for the lost call probability of 0.01.

Fiber-optic microcellular system has been studied actively as an excellent system for solving the equipment cost problems in microcellular systems. However, the occurrence of intermodulation distortion (IMD) arising from the nonlinearity of the laser diode used for E/O conversion which degrades the transmission quality is a serious problem in this system. In this paper, we propose a new frequency switching/IM3 reduction method, which dynamically reassigns the carrier frequencies to minimize the carrier to IMD power ratio under the hostile environment with time-varying received carrier strength, and analyze the performance improvements by the proposed method. The improvements obtained both for the worst value of the overall CNR and for the overall CNR in a specific user are numerically made clear. It is also shown that if the interval between frequency reassignings is set less than one second, a sufficient improvement in the overall CNR is achievable.

A new arithmetic multiple-valued algebra with functional completeness is introduced. The algebra is called Neuro-Algebra for it has very similar formula and architecture to neural networks. Two canonical forms of multiple-valued functions of this Neuro-Algebra are presented. Since the arithmetic operations of the Neuro-Aglebra are basically a weighted-sum and a piecewise linear operations, their implementations are very simple and straightforward. Furthermore, the multiple-valued networks based on the Neuro-Algebra can be trained by the traditional back-propagation learning algorithm directly.

This paper summarizes basic system design for an optical fiber feeder for microcellular mobile communication systems. The optical feeder enables compact and low cost base stations, easy radio channel control and flexible mobile communication systems. Basic transmission characteristics are investigated through optical transmission experiments. By using these results, feeder performance is estimated and optimal system parameters are designed.

We have achieved the room temperature cw lasing operation of GaInAsP/InP surface emitting lasers for the first time. By employing a buried heterostructure with 1.3 µm range active region and a MgO/Si heat sink mirror, cw operation was obtained up to 14 with the threshold current of 22 mA.

This paper analyses the amplification characteristics of a two-loop controlled switching power amplifier for a digital portable telephone and presents the amplifier which has a flat gain and small phase delay from dc to 100kHz. This amplifier is a modification of a switching regulator and it uses two-loop control to achieve a wideband amplification characteristic. Optimum amplification characteristics, however, can't be designed by using the conventional method for designing a switching regulator because a flat gain and small phase delay in an amplification characteristic has not been considered for most switching regulators. This paper analyses in detail the small-signal transfer functions of the switching power amplifier and shows the behaviour of zero and poles. It also shows the boundary condition of large-signal operation. A new design procedure of a switching power amplifier is presented, and the analytical results are verified by experiments.

We propose a decoding algorithm for the t-EC/AUED code proposed by Böinck and Tiborg. The proposed algorithm also reveals some remarkable properties of the code.