摘要:

AbstractFor some distributed control applications, a highly reliable, high‐speed time‐critical communication network is required. Time‐critical communication ensures completion of data transmission for an application, or that of transaction within a time specified by the application. A protocol has been presented for time critical communication that achieves highly effective traffic ratio of time critical data using two‐level data queues. Estimates of effective traffic ratio are derived for the authors' protocol. Estimation parameters are input traffic load, ratio of time critical data in offered load, and time width for completion of data trans

ISSN:0882-1666    

DOI:10.1002/scj.4690270401

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

年代:1996

数据来源: WILEY

摘要:

AbstractIn this paper an optimum algorithm to translate control flow graphs to dataflow graphs is proposed for dataflow execution of sequential programs. Some of the existing analysis methods restrict the specification of a program to be processed while others require a very high analysis cost. The algorithm proposed in this paper (CDtranslation algorithm), (1) with a very low cost, and (2) for any control structure that can be described by a control flow graph, (3) can generate dataflow programs that give an optimum dataflow execution. Furthermore, this proposed analysis algorithm is designed to handle task level control flow graphs as well as instruction level control flow graphs, which are accepted by the existing methods, so that optimum control is possible for task level dataflow execution.

ISSN:0882-1666    

DOI:10.1002/scj.4690270402

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe VPP500 system is a commercial, distributed memory, parallel computer system based on vector parallel architecture. The software of the VPP500 system is described here. The OS is UNIX‐based, enhanced with distributed parallel features. A system that is easy to use and has high performance requires a (1) realized one‐system image; (2) pursued ultrahigh performance; and (3) enhanced operation of the system. To satisfy two fundamental requirements of a language processor system, (1) effective use of the existing program assets and (2) extraction of potential performance of hardware system, we have implemented VPP Fortran (the standard FORTRAN77 enhanced with the features of parallel processing). The various data on VPP Fortran show that the VPP500 system, which consists of hardware, OS and language processor system, has both high performance and high efficie

ISSN:0882-1666    

DOI:10.1002/scj.4690270403

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe super database computer SDC‐II is a back‐end massively parallel SQL server, designed for superhigh‐speed processing of queries in relational database systems. The experimental system is composed of tightly coupled parallel processing modules, each containing up to seven CPUs, four disks and two data network interfaces, and a highly functional omega network connecting eight such modules.This paper describes first the parallel relational database processing system, and then proposes a query execution model for its efficient realization. The execution model uses four basic primitives (getPage, putPage, getFree and putFree), which are functions. Processing is performed pagewise using these basic operations. GetPage fetches a page from the disk read buffer, followed by getFree to acquire a free page from the free page pool. The results are sent to a disk write buffer with putPage, and putFree frees the page fetched from the read buffer. In other words, the processing progresses with the page moving around the system. The dataflow control for the input/output processes in the secondary memory for the efficient query processing are discussed in detail later. The method for avoiding and recovering from deadlock are described. Finally, the software system implemented on the SDC‐II is considered describing its components and functions. Measurement results for the execution of the TPC‐D benchmark are shown, indicating that efficient operation is

ISSN:0882-1666    

DOI:10.1002/scj.4690270404

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

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper studies the hypercrossbar network which has high flexibility and extensibility as a massively parallel computer network. Its performance is evaluated in nonroutine processing by computer simulation and theoretical analysis. To improve its performance, an implementation method of adaptive routing based on dynamic path determination is proposed, and its performance is evaluated by computer simulation. It is verified that the hypercrossbar network with adaptive routing has about 45 percent of the peak throughput at random transfer. Furthermore, its effectiveness is extremely high for applications with hot‐spot. It can attain about 8 times throughput compared with fixed routin

ISSN:0882-1666    

DOI:10.1002/scj.4690270405

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

年代:1996

数据来源: WILEY

摘要:

AbstractA self‐stabilizing algorithm is a distributed algorithm that achieves its intended behavior regardless of the initial configuration.This paper discusses the self‐stabilizing algorithm for the ring orientation problem (ROP). ROP is a problem where all processors on a ring network are to be oriented either clockwise or counter clockwise. It is known up to now for the network composed of an even number of processors that there does not exist a deterministic self‐stabilizing algorithm to solve ROP under the D‐daemon or the R/W daemon. On the other hand, a probabilistic self‐stabilizing algorithm is known for ROP on a ring network with an arbitrary size under the D‐daemon. This paper also presents a self‐stabilizing algorithm for ROP on a ring network with an arbitrary size under the C‐daemon. The result indicates that the classes of problems that can be solved by the C‐daemon and the D‐daemon, respectively, are subs

ISSN:0882-1666    

DOI:10.1002/scj.4690270406

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

年代:1996

数据来源: WILEY

摘要:

AbstractInterpolative DPCM has superior prediction capabilities compared to the commonly used extrapolative DPCM, but since quantization errors accumulate during decoding, and since quantization errors are expanded by expansive coefficients that are proportional to the image size, IDPCM has the weakness that coding errors become excessive. In this paper, offsets are added to the pixel values of the image that is to be coded, where a new method is proposed for the offset adjustments such that a transformed image with smaller quantization errors results. The effectiveness of this algorithm is confirmed by simulations with real images. Since the offset values are determined by the solution of a nonlinear minimization problem with an evaluation function that is the coding error derived from the function of the offsets values and quantization errors of the adjusted image, a minimization algorithm that combines a descent method with a one‐dimensional search and which exploits properties of the evaluation function is used. Furthermore, coded data rates are estimated, and rate‐distortion curves are determined with the use of a hypothesized image probability model. By combining this method with a previously proposed subsampling method, it is possible to improve the image quality by 3 [dB], or reduce the coded rate by 0.3 [bits/pix

ISSN:0882-1666    

DOI:10.1002/scj.4690270407

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

年代:1996

数据来源: WILEY

摘要:

AbstractEstimating the gradient of a plane from a single still image is an important procedure in the 3‐dimensional reconstruction of an object. This paper proposes a method of detection of a gradient from the distortion of textures on an object and the rate of its change. It is assumed that the 3‐D object consists of a single plane having uniform textures. The gradient of the plane is estimated from 2‐D frequency data considering that the image signal obtained by a projection has a variation of its local frequency characteristic. A peak frequency is extracted as a local frequency by estimating a non‐stationary spectrum, and the gradient is obtained from the rates of variations of its direction and magnitude. In this way, the gradient can be obtained quantitatively, even if the data of spectrum of a texture (without any gradient) are not known.Two methods of estimating a nonstationary spectrum are proposed i.e., the short‐time Fourier transformation method (STFT), and a method using AR model, and they are compared. The proposed method is applied to an image having periodic patterns, and to a statistical image. The results show the usefulness of t

ISSN:0882-1666    

DOI:10.1002/scj.4690270408

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

年代:1996

数据来源: WILEY

摘要:

AbstractIn conventional digital image processing, topological properties have been studied only for selected types of neighborhoods such as a 4‐ or 8‐pixels connection. This paper analyzes properties of a finite topological space by defining it as a topological space with no restriction on the shape of a neighborhood. This leads to the identification of topological properties which are independent of the shape of a neighborhood and can be applied to image processing using neighborhoods other than a 4‐ or 8‐connection. Since a finite topological space can treat only a single neighborhood this cannot be applied to image processing which uses multiple neighborhoods simultaneously. A finite topological space has been extended to a formal topological space having multiple neighborhoods, and its properties are analyzed in this paper.This theory is then applied to image processing. It has been difficult to detect scratches on a surface with patterns, such as a hard disk or a hairline‐finished metal, by using a conventional digital topology because the scratches often consist of many small blocks and their images are stained by noise. The properties obtained through the formal topology have successfully been applied to these problems, and its effectiveness has been

ISSN:0882-1666    

DOI:10.1002/scj.4690270409

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

年代:1996

数据来源: WILEY