摘要:

AbstractGroup and multicast communication provide basic functions for many applications in distributed computing. In such a communication, the causal ordering property among messages should hold throughout distributed sites. Several communication protocols for this purpose have been designed so far. They are designed mostly under the strong assumptions: there is no loss of messages in the communication channel or the order of the messages is preserved or both.However, in WAN environment, it is desirable to design such a protocol without assuming these conditions from the efficiency point of view.In this paper, a protocol which provides the causal ordered broadcast in a non‐FIFO network is investigated. The non‐FIFO network is defined as the network in which there exists possibilities of loss and disorder of messages. The purpose of this paper is to perform experimental evaluations to a causal ordering protocol which is specially designed for a non‐FIFO network.The protocol is implemented as a software system, and the performance evaluation of the system is done by experiments. In addition, a simple approximation of the queue length of the system is proposed. The applicability of the approximation also is investi

ISSN:0882-1666    

DOI:10.1002/scj.4690260801

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA multiple‐access method is proposed for simultaneously providing video data to more than 100 terminals in a video‐on‐demand system. The proposed method divides up each video program into segments, stores the segments on multiple disk drives, and performs time‐division‐multiplex reading based on the time‐slot sequences for each disk drive that are periodically phase shifted with respect to each other. This method features: 1) theoretical limit on the maximum number of multiple accesses that can be implemented, and straightforward upscaling of the maximum number of multiple accesses because the amount of buffer memory needed for each terminal is fixed; 2) no request loss, even when many terminals request the same program because the load for reading each video program is always distributed across all the disk drives; and 3) system control that guarantees read‐request response times within a specified value by allowing the skipping of a very small amount of leading information in each video program. Numerical examples show that this access method makes it possible to design a system having no request losses and a guaranteed response time within one second, even for simultaneous accesses by

ISSN:0882-1666    

DOI:10.1002/scj.4690260802

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractRecent anatomical studies have clarified that local image velocity is detected by a sequence of cells on the magnocellular pathway of the visual cortex. To the authors' knowledge, however, neither neurophysiological nor theoretical studies have been able to clarify the roles of these cells in velocity detection.The authors propose that the cell sequence constitutes a function hierarchy for detecting velocity. Lateral geniculate nucleus cells first introduce a time delay. They are followed by two simple cell types that perform a Hough transform and a spatio‐temporal correlation. Complex cells then perform an accumulation to convert the velocity into a sine wave composed of activated cells in the complex cell array. The amplitude and phase of the wave correspond to the velocity speed and direction components. Finally, motion‐detection cells in the middle temporal area perform an inverse Hough transform to extract the wave.Five types of cells are modeled as a series of formulas that represent the synaptic functions of neurons. The modeled cells exhibit the same selectivities to stimuli as actual cells. They detect the velocity from various moving stimuli, including dots, straight lines and cur

ISSN:0882-1666    

DOI:10.1002/scj.4690260803

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe relationship between the recognition rate of handwritten numerals and the normality of the distribution of their features has been investigated experimentally with a large amount of data in various combinations of quantized orientations and regions. The recognition method is based on the histogram of local orientation of contours of each numeral. To obtain a more accurate orientation quantization, the effectiveness of the orientation quantization using the gray‐scale gradient has also been investigated. The results show that: (1) to increase the dimensionality of features, it is better to increase the number of quantized orientations, keeping the number of regions small (e.g., 4 × 4 or 5 × 5); (2) in the same dimensionality, the better the normality of a feature distribution, the higher the recognition rate; (3) a quantization of orientations using gray scales is effective for normalizing a feature distribution; and (4) the filter processing in reduction of the number of quantization scales improves the normality and recognition rate. The recognition of handwritten numerals collected from actual posts were carried out by using the gray‐scale local‐orientation histogram (400 dimensions). A correct recognition rate of 99.18 percent (mean value) has been o

ISSN:0882-1666    

DOI:10.1002/scj.4690260804

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractTechnology of recognizing a 3‐dimensional object and finding its direction from a 2‐dimensional image is important in practical applications such as classification of industrial products. A typical conventional method for this purpose uses the 3‐dimensional structure of the object such as its edges and surface shapes. However, extraction of a 3‐dimensional structure with a high accuracy, notably that of an arbitrary shaped object, is difficult.This paper proposes a method of recognizing a 3‐dimensional object by using a 2‐dimensional collation. A 2‐dimensional collation which requires no 3‐dimensional feature has never seriously been examined, because it has been considered that the amounts of computation and a memory for learning the 2‐dimensional image data (which are very complex due to the variations of viewing and lighting angles) are not acceptable. The proposed method can learn a 3‐dimensional object as a set of 2‐dimensional images by using a new parametric eigenspace approach with a small memory capacity. The proposed method can easily learn a 3‐dimensional object from its 2‐dimensional image, and can recognize the object and estimate its pose. This paper includes experimental comparisons between the proposed method and other 2‐di

ISSN:0882-1666    

DOI:10.1002/scj.4690260805

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThere has already been a report on the method to improve stereo measurement accuracy by integrating stereo data from multiple viewpoints, which employs a local optimization technique, the nonlinear optimization method using iterative calculation. The problem is that estimated results depend on the initial values of the iterative calculation. If the calculation begins with unsuitable values, a correct estimation cannot be made. This paper presents a new method utilizing a genetic algorithm to search for initial values for the nonlinear optimization process in multiple viewpoint stereo measurement. In this method, a one‐dimensional matrix is created. Called an “individual,” it consists of parameters to be determined. Next, a population is formed which consists of several individuals. Then three kinds of genetic operations are performed on this population, crossover, mutation and selection, which evolve the population to fit the environment. This evolution process is repeated and the evolved result is used as the initial values for the iteration calculation. The efficiency of this method is confirmed by simulation and an outdoor exper

ISSN:0882-1666    

DOI:10.1002/scj.4690260806

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper proposes a new recognition method of coronary arterial stenosis in DSA image, because conventional evaluation algorithms have not been satisfactory to medical doctors. To solve this problem, the neural network which takes into account the experience of the medical doctor is employed. This method consists of the extraction of characteristic parameters which are highly correlated with stenosis and the recognition of stenosis by the neural network. By means of phantom experiments and clinical evaluation, the efficiency of the proposed method has been shown.

ISSN:0882-1666    

DOI:10.1002/scj.4690260807

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA physically based environment of Artificial RealiTY for dress simulation (PARTY) which shows fully dressed humans in various environments is described. In PARTY, a dynamically deformable cloth model of a dress plays the central role. This paper proposes a new dynamically deformable cloth model that can handle actual nonlinear kinetic properties of cloth measured by mechanical experiments, and also propose a numerical method appropriate for PARTY. The numerical results of the Drape Test are compared with the shape of real cloth in experiments.

ISSN:0882-1666    

DOI:10.1002/scj.4690260808

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe expert systems (ES) in the past have mostly been constructed to solve particular problems, and it is difficult to share or reuse the obtained knowledge. This has been a serious drawback in efficiently constructing an ES. Since practical application of ES is in progress, and the practical usefulness is recognized widely in society at present, it is very significant to work for sharing reuse of knowledge.The authors considered the accident restoration assist of the primary substations, and attempted to construct a reusable knowledge base. In this paper, first, the conventional ES to assist the accident restoration of the primary substations is analyzed, and it is pointed out that the knowledge is restricted to particular substations and, consequently, cannot directly be reused. Then the methodology for constructing the reusable knowledge base is discussed.Based on the presented methodology, the constructing procedure for the reusable knowledge base for the accident restoration of the primary substations is discussed in detail. The knowledge of the expert in problem‐solving is analyzed and is divided into the following three classes: 1) the object model; 2) the general rules; and 3) the knowledge specific to the particular primary substations.Finally, the procedure‐generation system for the accident restoration of the primary substations is described. Through the test using the case data of 10 accidents in 2 primary substations, it is verified that the same operation sequence can be generated as the one by the exp

ISSN:0882-1666    

DOI:10.1002/scj.4690260809

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY