The user interface part of an application program can be easily and compactly constructed by combining the parallel execution primitive Linda and the state transition description language Flex with a general purpose programming language. With this approach, a wide range of interfaces can be constructed without using languages or systems specific to user interface design. Using these tools, parallel execution, separation/communication between the application and the interface part, and complicated dialogs can easily be specified. In our implementation, the specification is compiled into C and runs efficiently without any runtime system.

In this paper, the general Petri net liveness problem is discussed. First, a useful necessary condition and a simple sufficient condition for liveness of general Petri nets without time are derived by using only the concept of the deadlocks. Next, it is discussed that the strong motivations, to rebuild the expanded definitions of deadlocks and traps, and to clarify their structural properties and the mutual relationships between deadlocks and traps, result from the main theorems of this paper. It is also shown that the theorems derived in this paper are applied to some timed Petri nets because some timed Petri nets are equivalently transformed into general Petri nets without time by the proposed transformation rule, remaining the basic structural properties such as boundedness, liveness, and reachability of those timed Petri nets unchanged.

This paper proposes an analysis method of a priority scheme for mixed Continuous-Bit-Rate (CBR) and burst traffic contending based on Asynchronous Transfer Mode (ATM) which applied the future B-ISDN. The method is analyzed througn two separated source models; binary source model for burst traffic and random source model for CBR traffic. First we defines arrival process using the two source models according to traffic characteristics so that in adaptation to queueing modeling the system is analyzed through M/G/1/N. Next in view point of service process three priority schemes: push-out scheme, partial buffer sharing and separate route for each traffic loss are proposed. Here we impose two different priority classes on each source model. With the use of superposition of traffic from a number of independent random sources and binary sources, the partial buffer sharing scheme is proved to be best in three priority schemes for addmissible load and cell loss probability. In this paper, we propose partial buffer sharing scheme with priority scheme for two different traffics.

Translation of the scalable outline font data as represented by a set of control points of the cubic Bezier curve, etc. into the bitmap data for desk-top publishing (DTP) applications requires a significant amount of computation. In this paper, we propose a special purpose chip called KAFOG for the high-speed generation of bitmap font from the Hangul PostScript file for screen display as well as LBP (Laser Beam Printer) output. KAFOG chip was implemented in 1.5 µm CMOS gate array using 17 K gates. The computation throughput of the KAFOG chip is 250 K cubic Bezier curve segments (each curve segment is composed of four control points) per second at the clock frequency of 40 MHz.

In many parallel processing systems, interference among jobs, which comes from resource contention, causes performance degradation. In order to solve the problem of resource contention, an important question is: "How shall we optimize jop scheduling policy?" However, the traditional queuing theory assuming a first-come-first-served policy is not suitable for analyzing scheduling policy. A new method called Stochastic Petri Nets (SPN) is suitable for analyzing scheduling policy, because with it job arrival states, resource assignment states, and job flow due to these states can be modeled. However, the describing powers of places and transitions, elements of SPN, are as weak as Assembler in program languages. If we model scheduling logic in detail with SPN, that model becomes huge with a great number of places and transitions. Not only modeling of scheduling logic itself becomes difficult, but also analyzing of the model becomes difficult. In this paper, we consider a system in which resource contention causes job interference, and propose a method of analyzing scheduling policy for interference avoidance. In this method, for each scheduling policy, we introduce functions between job execution performance and system states. By incorporating this function into a SPN model, we cut down the size of the model. We apply the proposed method to analyzing performance of the control policy of a magnetic tape library, and show the efficiency and limit of this method.

A wide beamwidth and broad bandwidth microstrip antenna is presented. It consists of a rectangular patch antenna and a pair of parasitic short circuit patches placed over the radiating edges of the rectangular patch. The parasitic element not only widens the bandwidth of the antenna but also forms a narrowed pair of radiating edges, so the E-plane beamwidth becomes broader. An antenna trial model achieved a bandwidth of 16% (VSWR1.5) and a broad E-plane beamwidth of 165 degrees.

Past work and recent trends in the development of antenna systems for mobile communications are reviewed. Modern antenna design is not only concerned with the antenna elements, but also involves consideration of factors related to propagation, systems, and environmental condition. Major developments in the field are described, and some prospects for the future are also introduced.

In systems where the same data are distributed in plural memories, data consistency must be maintained after a failure. It is important to verify that error recovery specifications guarantee the data consistency, and it is difficult because system status is nondeterministic after a failure occurs. In this paper, a method of modeling and verifying error recovery specifications by using colored Petri nets is proposed. First, the concept of data freshness is introduced to describe the relationship between the data explicitly. Then, a flow-chart that describes data renewal sequences is converted into a Petri net. Failure events and recovery procedures are added to the model. Consistency is verified by investigating reachable markings and by checking for the existence of states in which data freshness is contradictory. The number of reachable markings is generally enormous and sometimes infinite. Thus, the condition in which two markings are identified for verification is studied. The introduction of the equivalence relation itno reachable markings reduces the number of the markings to be verified. The usefulness of the proposed approach is demonstrated by a read/write process of a disk controller with a built-in cache memory. This example makes it clear that the analysis is helpful not only for checking whether the data is consistent, but also for designing the recovery procedures maintaining the data consistency.

We present a method that uses optical flow to estimate facial muscle actions which can then be recognized as facial expressions. Facial expressions are the result of facial muscle actions which are triggered by the nerve impulses generated by emotions. The muscle actions cause the movement and deformation of facial skin and facial features such as eyes, mouth and nose. Since facial skin has the texture of a fine-grained organ, which helps in extracting the optical flow, we can extract muscle actions from external appearance. We are thus able to construct a facial expression recognition system based on optical flow data. We investigate the recogniton method in two ways. First, the optical-flow fields of skin movement is evaluated in muscle winsows, each of which defines one primary direction of muscle contraction to correctly extract muscle movement. Second, a fifteen dimensional feature vector is used to represent the most active points in terms of the flow variance through time and local spatial areas. The expression recognition system uses the feature vector to categorize the image sequences into several classes of facial expression. Preliminary experiments indicate an accuracy of approximately 80% when recognizing four types expressions: happiness, anger, disgust, and surprise.

A successive iteration algorithm for estimating the response of a parallel two-wire transmission line terminated by nonlinear protective devices in an external electromagnetic pulse is developed and implemented for numerical simulation. The validity of the presented algorithm is assured by showing that the numerical result for a particular nonlinear impedance characteristics of the protective devices approaches the rigorous solution which is also derived here analytically.

The Fourier transform grid methos (FTGM) had been proposed previously by the authors for measuring in-plane strain distibution. In this paper, two automated grid methods are proposed using the FTGM. One is a method for measuring the shape of the full surface of a cylindrical object. A new forming grid method is proposed for introducing the FTGM into the slit projection method. In order to measure the full surface of the object, the object is rotated by a constant angle, the projected line is recorded and the line image is shifted by a constant number of pixels. The next recorded projected line is superimposed in the same image memory. By repeating the above operation, a grating image is formed in the image memory. The formed grating iemage is precisely analyzed at once by the FTGM. The other is a shape and strain measurement method for a curved plate. In the conventional automated grid method, because the position of a grid point is exprssed by an integer number of pixels, it is difficult to use for accurate measurement. Using the FTGM, the position of the grating is measured by the decimal number of pixels by analyzing the phase distribution. The accuracy is higher. Moreover, since each pixel point has a phase, matching for corresponding points between different images is easily performed by comparing the phases of the points. Two applications for medical and mechanical experiments are presented.

The measuring and display system for a merathon TV program employing a realtime image processor and a fast graphic processor has been developed. The system consists of two parts, the step frequency subsystem and the Computer Graphic display subsystem. In the first subsystem, the step frequency for a marathon runner is detected from the image signal by tracking the motion of the runner's face. In the second subsystem, the data for the position of each joint in the runner's leg are prepared beforehand. By applying the step frequency to those prepared data, the runner's motion is drawn out as an animation.

This letter presents a cancellation technique of parasitic poles of operational amplifier (op amp) in active filter design. To minimize the effect of the parasitic poles, a three-pole model of op amp is utilized. A second order highpass filter is evaluated both theoretically and numerically.

A new system for high speed and continuous 3-D measurement is presented. It is based on slit-ray projection method. Remarkable features of our system--high speed and continuous measurement--mainly come from its image plane constructed by PSD array which is horizontally non-divided and linear, whereas vertically divided in numbers. Each row PSD element is attached to respective analog signal processor, A/D converter and memory element. By the virtue of this configuration of the image plane, we can store the positional information of slit-like image on the image plane into memory elements in real time, without waiting for one frame interval as is required in the conventional methods with scanning type image grabbers. As the result, we can scan the slit-ray at a constant high angular velocity and calculate the deflection angle of the slit-ray from scanning time of it, which is set on the address bus of memory elements in our system. Thus, basic datum for 3-D measurement are acquired during only one scanning of slit-ray at high speed in the form of addresses of memory elements and datum stored in them. Moreover, if we use large capacity and/or dual port memories, we may continuously obtain 3-D datum of as many scenes as we want. Trial system has verified our method showing data acquisition time per scene within a few milliseconds and enabling us to obtain 3-D datum continuously at a rate of hundreds scenes per second.

In this paper, methods to analyze the convergence and steady-state characteristics of an adaptive notch filter with two input structure are proposed. The adaptive detection of a sinusoid with additive Gaussian noises has been investigated. Expressions for the necessary iteration of convergence are derived. An analysis of steady-state coefficient error has been also obtained. The analysis of this paper clarifies the effects of colored Gaussian noise and the noise correlation between primary input and reference input. Finally, the results of computer simulations are shown which confirm the theoretical predictions.

In hypercube multiprocessors it is important for the resource manager to be able to recognize and allocate subcubes of adequate sizes. Known allocation schemes, such as Gray code allocation strategy, do not consider hypercube in which there are faulty processors. However, faulty processors destroy some of the subcubes which resource manager can recognize searching on the current allocation list. This decreases the allocation performance. We propose a fault tolerant allocation algorithm which reconstucts allocaton list in order to remedy damege caused by faults. First, one measure of goodness of allocation list is introsuced referred to as a subcube recogizability. Then, general rules for allocation list restructuring are formulated. Accordingly, a two-step algorithm is developed which builds a new allocation list with improved subcube recognizability. Namely, the number and/or size of fault-free recognizable subcubes on the new list are maximal, for the given distribution of faults. Such a graceful degradation of allocation performance in injured hypercube is achieved just by means of prosessor readdressing. At last, the correctness and optimality of the algorithm are proved.

Image labeling is a process of recognizing each segmented region properly exploiting the properties of the regions and the spatial relationsships between regions. In some sense, image labeling is an optimization process of indexing regions using the constraints as to the scene knowledge. In this paper, we further investigate a method of efficiently labeling images using the Markov Random Field (MRF). MRF model is defined on the region adjacency graph and the labeling is then optimally determined using the simulated annealing. To endow the adaptability to the MRF-based image labeling, we have proposed a parameter estimation technique based on error backpropagation. We analyze the proposed method through experiments using the real natural scene images.

In this paper, two methods for improving the performance of DSBC (Dynamic bit allocation Sub-Band Coder) are proposed. One is to modify the bit allocation algorithm since conventional dynamic bit allocation algorithm is computationally heavy, while the other one is to weight the subband to reduce hissing noise. Instead of inserting the Gaussian noise in regeneration of empty band, the subband weighting method is to utilize shaped subband signal as empty band signal. The simulation result shows that computational complexity is reduced about 10%, and perceptual hissing noise is suppressed noticeably.