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Kron's Diakoptics is well known as a solution method of large-scale network problems by tiering. It interconnects all tiered subnetworks with tiered branches simultaneously by one step. We introduce Multistep Diakoptics (MSD), which interconnects tiered subnetworks partially with subsets of tiered branches step-by-step, and completes interconnections by multiple steps. By using the parallel computation method, the MSD algorithm uses less computation time than is the case with the standard Diakoptics algorithm. This paper introduces the MSD algorithm and the program that is executed by each computer in a multiple computer system and solves only a tiered subnetwork problem. We also explain the contents of data which must be transmitted to other computers. Furthermore, computation complexity, communication complexity, and organization of block data used in each computer for simulation of large-scale nonlinear networks are discussed, and a simple method for applying MSD in practice is introduced. It is concluded that, characteristically, MSD reduces the computation time in accordance with the number of computers if the data transmission time can be neglected. [ABSTRACT FROM AUTHOR]

This paper discusses the structural analysis algorithm for line patterns, based on the distance transformation of a line pattern by iterative local parallel processing. Although parallel processors have been applied recently to image processing, the processing of line patterns in the past was based primarily on the transformation of the object pattern into the list structure or symbol strings. Few studies have been made on the parallel processing algorithm for a line pattern. From such a viewpoint, this paper presents parallel-type algorithms for loop counting, loop extraction and arc decomposition, among the procedures for processing line patterns. Properties of these algorithms also are discussed. The method proposed here is based on the distance transformation (Min. type) for line patterns we developed, and can be performed by iterative local parallel processing, in the same way as the distance transformation itself. [ABSTRACT FROM AUTHOR]

The specification for a communication protocol is generally represented by a finite-state machine, and the operation of the machine is represented by transitions among states. The device implementing such specification is called the implementation under test (IUT). It is important for the IUT that its operation should be verified for all state transitions on the finite-state machine given in the specification. This test is called the conformance testing. In such testing it is important to generate efficiently a route containing all state transitions from the initial state. This problem is called the test sequence generation problem. This paper considers the test sequence generation problem for a communication protocol and proposes an application of an algorithm for satisfiability problem (SAT) that can flexibly handle various constraints, such as the order constraint and the time constraint among multiple constraints. The proposed method is applied to the dynamic host configuration protocol (DHCP) and its effectiveness is demonstrated. © 2003 Wiley Periodicals, Inc. Syst Comp Jpn, 34(11): 20–29, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10482 [ABSTRACT FROM AUTHOR]

In general, systems are comprised of a large number of elements and might be very symmetric. In verification of such systems, they are reduced while upkeeping their global structure and verified with the intuitive expectation that the verification of such reduced systems will yield almost the same results as those of the original ones. However, such verifications do not guarantee the success of original system verifications. In this paper, the target is verification of arbitrary scale systems with star-shape configuration which can be expressed by Petri nets. The proposed algorithm explores the reachable state space with no dependency on system scale. © 2001 Scripta Technica, Syst Comp Jpn, 32(14): 41–53, 2001 [ABSTRACT FROM AUTHOR]

This paper proposes a quasi-competitive network in which the mass reaction intensity of the elements in the intermediate layer is kept constant as a model that approximates the continuous nonlinear function. As the loss function, the local loss function is considered. It is composed of the error and the local model loss term reflecting the local model size. The learning algorithm of the quasi-competitive network including the change of the number of elements is derived from the local loss function. It is shown by numerical experiment that the quasi-competitive network can form quickly the structure reflecting the target function and has a high generalization power. It is shown also that the high generalization power is due to the constant mass reaction intensity of the elements in the intermediate layer of the quasi-competitive network. [ABSTRACT FROM AUTHOR]

This paper describes algorithms of magnifying/reducing, rotation, and border following for binary document images by using a segmented block code. Document images such as facsimile images are composed of a large number of binary data. Thus it is difficult for a small-sized conventional computer to process efficiently a whole document image in a pixel-by-pixel manner. Our algorithms described herein use segmented block coded data instead of pixel data. In the segmented block coding scheme, blocks which are two-dimensional contiguous black pixel areas are extracted and coded by their locations and shapes. Since this coding scheme compresses the amount of data required to process and produce the data form which is suitable to deal with by conventional computer, our algorithms using this coded data work efficiently. Also, there is another advantage in that the results of magnifying/reducing or rotation of Images are obtained in the form of a segmented block code. This means that we can manage document images in a unified manner. [ABSTRACT FROM AUTHOR]

This paper presents basic concepts and fundamental algorithms for processing three- dimensional digitized images (3D images). A 3D image is a pictorial datum obtained by measuring physical quantities distributed at every point in 3D space and arranging the measurements on a 3D array. First, we present several basic concepts concerning geometrical properties of 3D images, which include connectivity, the connected component, the Euler number, and deletability. Then we explain outlines of basic algorithms derived by using the forementioned concepts based on research results by the authors' group. Procedures referred to here are as follows: calculation of the Euler number, deletability test of 1-voxels, shrinking, thinning, and border following. Finally, we add 51 refer- ences which may aid more detailed research; these references also will supplement the brief explanations and small number of procedures we are limited to in this article. [ABSTRACT FROM AUTHOR]

The median filter is used frequently in image processing for smoothing while retaining edges. This paper describes an efficient method to calculate the rank filter, which is a generalization of the median filter and includes it as a special case. The presented method is simpler than the method proposed previously by Danielsson. A strict proof is given for its validity. An application to the construction of a logical circuit realizing the algorithm is also described. [ABSTRACT FROM AUTHOR]