摘要:

AbstractTo use multiprocessor systems efficiently, several load balancing algorithms have been adopted widely. However, most of the algorithms proposed so far can be applied to FCFS systems, and only a few can be applied to time‐sharing systems in wide use today. This paper proposes a load balancing algorithm designed to reduce the average response time of processes, introducing a load measure which takes into account the distribution of the work demand of each kind of process. This algorithm can be applied to a multiprocessor system with round‐robin scheduling discipline. This algorithm also seems easy to implement on actual systems because load balancing is made by assigning new processes to the lightest loaded processor rather than migrating running processes. According to the simulation experiment, the algorithm proposed here improves the average response time compared with that of the “Join the Shortest Queue” algorithm over all situations inves

ISSN:0882-1666    

DOI:10.1002/scj.4690210801

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe RSA public key cryptosystem is one of the cryptosystems which can be applied not only to the security protection but also to the verifications of other users and messages. It is one of the most important techniques in ensuring the security of information. To construct a secure RSA public key cryptosystem, the key must be generated using primes which are robust against a “(p+ 1) factorizing attack.” For this purpose, Gordon proposed a method of generating the key by sieving using known primes less than 8 bit and by employing the higher‐order exponential calculation. This paper is an extension of Gordon's approach. The range of known primes is defined optimally through an evaluation for the sieving primes less than 32 bit. The exponential calculation is simplified. The method is implemented on a program. Numerical experiment is made on a 32‐bit workstation, and the practical usefulness of the method is v

ISSN:0882-1666    

DOI:10.1002/scj.4690210802

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

年代:1990

数据来源: WILEY

摘要:

AbstractA method for extending the behavioral specification and verification of state machine networks by event sequences to non‐deterministic behavior is presented. The nondeterministic behavior is described by a function between sets of event sequences instead of between sequences. Both the module composition and loop connection operations are modeled by the function composition and the least fixed point, respectively, just as in the deterministic case. Two application examples are described. The example with alternating bit protocol via unreliable communication lines indicates that the method detects the possibility of message stack just as the verification by temporal logic does, while the proof steps of our method are shorter. The second example discusses the cause of the Brock‐Ackerman anomaly and a condition to avoid

ISSN:0882-1666    

DOI:10.1002/scj.4690210803

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

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper proposes a virtual optical disk method which uses the write‐once optical disk as a rewritable secondary memory on existing operating systems. The method also provides revision history of all files on an optical disk. The virtual disk method realizes a virtually rewritable disk (virtual disk), using the write‐once optical disk. The rewriting is simulated using the disk sector as the unit. It completes re‐writability and revision control without additional rewritable memory devices such as magnetic disks. The method is actually built into an OS for a personal computer, and the access speed of a virtual disk is made almost equal to that of a floppy disk by adding an optical disk cache memory. The virtual disk method has a merit in that it can cope with write‐errors in a write‐once optical disk, which may occur consecutively at writing process. Thus, it is seen that the virtual optical disk method is a useful means of this medium m

ISSN:0882-1666    

DOI:10.1002/scj.4690210804

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

年代:1990

数据来源: WILEY

摘要:

AbstractA tremendous amount of time is spent in testing in the development of software products. Most of the test methods at present, however, are inefficient since the characters of the software defects are not well considered. From such a viewpoint, an efficient software test should be executed, taking into consideration the characteristics of the software defects. Examining the actual defects, it is found that a large number of defects exist due to specification changes. On the other hand, no testing method has been developed aiming at the detection defects of this type. Thus, it is necessary to develop a method of testing that can effectively detect the incorrect modifications accompanying the specification changes. As a result of detailed examinations of the actually produced defects due to specification changes, a concept called restriction element is introduced, and it is shown that the defects can adequately be described as the incorrect elimination/addition of that element. A theorem is shown which indicates when an incorrect elimination/addition of restriction element is produced, which of the input areas contain the data producing a behavior different from the specification. A method of determining test input areas is proposed based on that theorem. The test, based on the proposed determination of the test input area, can securely and effectively detect the incorrect modification accompanying the change of external specifications.

ISSN:0882-1666    

DOI:10.1002/scj.4690210805

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe robust fault tolerance is a property that even if an error occurs in the arithmetic circuit, the result of operation does not differ much from the correct value. Such a property will become more important in the construction of a highly safe system. In the present digital system, the weighted code is used in representing numerical information. In this scheme, when an error occurs in a bit with a large weight, the result of operation will differ greatly from the correct value, affecting the safety of the whole system. from such a viewpoint, this paper proposes the distributed coding, i.e., the arithmetic circuit based on the number system with uniform weight 1. It is shown theoretically together with the result of execution that such a circuit is much better than the arithmetic circuit based on the weighted traditional code, in terms of the robust fault tolerance, i.e. the safety.

ISSN:0882-1666    

DOI:10.1002/scj.4690210806

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

年代:1990

数据来源: WILEY

摘要:

AbstractImage recognition technology using computers has been active recently. In image recognition, it is necessary to automatically extract elements such as straight lines, circles, numerical letters, and symbols from a picture. There are many cases in which the extraction of such elements is not easy because some elements overlap. This paper describes a method for extracting individual overlapping elements from a binary image. This method can extract an element which has a constant shape with arbitrary size or rotation angle, or with both an arbitrary size and an arbitrary angle. The method uses a single key point and several feature points on the model element to be extracted. The extraction is carried out by checking if the pixels corresponding to the feature points are present, with each pixel regarded as a key point of the model. This paper describes the algorithm, a method of extracting some important straight lines and circles in the picture using the algorithm, and experimental applications of the method to mechanical drawings. The results of the experiments demonstrate the successful extraction of straight lines, circles, arrows, and alphanumerics, and this confirms the usefulness of the proposed method.

ISSN:0882-1666    

DOI:10.1002/scj.4690210807

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

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper considers the continuous‐time model and the discrete‐time model for the neural network, and discusses the stability of the model and the convergence of the sensitivity computation algorithm. First, a sufficient condition is given for the global asymptotic stability of the model. Then the speed with which the solution approaches the equilibrium is evaluated. Based on the results obtained, the local asymptotic stability of the equilibrium solution of the multi‐stable circuit is discussed. The fault‐tolerant property of the model is discussed briefly. Finally, it is shown that under the same condition as the sufficient condition for the asymptotic stability of the model, a certain kind of general sensitivity computation converges in the globa

ISSN:0882-1666    

DOI:10.1002/scj.4690210808

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

年代:1990

数据来源: WILEY

摘要:

AbstractIn solving an optimization problem using a neural network, the representation schema which codes the solutions of the problem onto the configurations of the states of neurons must first be defined. The coding schema is called an internal representation of the problem and the representation is considered redundant when the schema uses only those configurations which are separate from each other at long Hamming distances. Under some conditions, the redundant representation is shown to be very effective in eliminating the local minima problem, which is one of the most crucial problems in the application of neural networks to optimization problems. In the redundant representation, a stochastic property which appears asymptotically when increasing the number of neurons plays an important role when the solution is read reliably from the random and erroneous states of networks. In these networks, a probabilistic states transition schema is introduced so that the network can escape from the local minima. By introducing the redundancy, the randomly changing configuration can keep the order in which the solution can be read while sufficiently preserving the randomness to escape from the local minima. The result in this paper shows a novel optimization capability of the network which has a highly parallel and nondeterministic computation schema as described in the foregoing.

ISSN:0882-1666    

DOI:10.1002/scj.4690210809

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

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper describes a prototype monochromatic X‐ray CT using synchrotron radiation and evaluates its spatial resolutions, noise in reconstructed images, and quantitatively. A monochromatized X‐ray using a crystal spectrometer is passed through a slit (width 25 mm, variable height 25 μm to 2.5 mm), and then irradiated on a rotating sample. The X‐ray passed through the sample is converted into an electrical signal by using an X‐ray detector with 1024 channels, and then fed into a computer input. This monochromatic X‐ray CT has a view field 25 mm in diameter. The CT has an X‐ray spectroscopy function and a direct magnifying function of projection using an asymmetrical Bragg reflection, as well as a function for conventional cross‐sectional images. This paper describes theoretical analyses of the spatial resolution and noise in reconstructed images which determine the capability of an X‐ray CT, and the experimental evaluation of the prototype CT. Theoretically, the spatial resolution is expected to be greater than 25 μm at a magnification of 5, and this agreed with experimental results, as well as the theoretically determined noise in reconstructed images. The prototype apparatus has an energy resolution of 0.1 percent (full width of half maximum) in an energy range of 7 to 40 keV. This makes an absolute‐value measurement of the X‐ray absorption coefficient possible, and this has been confirmed experimentally. By using this apparatus, it is possible to produce an image quantitatively indicating the distribution of a partic

ISSN:0882-1666    

DOI:10.1002/scj.4690210810

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

年代:1990

数据来源: WILEY