In many actual applications of the adaptive filtering, input signals as well as output signals often contain observation noises. Hence, it is necessary to develop an adaptive filtering algorithm to such an errors-in-variables (EIV) model. One solution for identifying the EIV model is a total least squares (TLS) algorithm based on a singular value decomposition of an off-line processing. However, it has not been considered to identify the EIV IIR system using an adaptive TLS algorithm of which stability has been guaranteed during adaptation process. Hence we propose a normalized lattice IIR adaptive filtering algorithm for the TLS parameter estimation. We also show the effectiveness of the proposed algorithm under noisy circumstances through simulations.

The present paper investigates a two-dimensional (2-D) adaptive lattice filter used for modeling 2-D AR fields. The 2-D least mean square (LMS) lattice algorithm is used to update the filter coefficients. The proposed adaptive lattice filter can represent a wider class of 2-D AR fields than previous ones. Furthremore, its structure is also shown to possess orthogonality in the backward prediction error fields. These result in superior convergence and tracking properties to the adaptive transversal filter and other adaptive 2-D lattice models. Then, the convergence property of the proposed adaptive LMS lattice algorithm is discussed. The effectiveness of the proposed model is evaluated for parameter identification through computer simulation.

Intending to contribute to constructing better multimedia network systems, we propose a new concept of image database system of which form of storage is featuring exponential or graceful oblivion and abrupt recollection like the human memory property. By virtue of this property of database storages that is realized by employing hierarchical or pyramidal image coding, the database memory and transmission costs can be significantly reduced. In this paper we will describe the details of the concept, the results of theoretical analysis based on a simplified model which reveals the effectiveness of the proposed system, the structure of an experimental prototype system and the result of an experimental image retrieval service carried out by implementing it over ATM high speed channels.

Stable phase locked states" are found amongst the equiliblia of the phasor model known as a generalized Hopfield model having complex-valued local states on the unit circle with centre at the origin. The asynchronous updating rule is assumed, and the energy decreasing characteristic is used to investigate a property of the equilibrium states. Some of the equilibria are shown to be fragile" in the sense that the energy is not locally convex. It is also shown that the local convexity of the energy is assured by a sort of consistency between the equilibrium and the connection weights.

This paper discusses a massively parallel interconnection scheme for multithreaded architecture and introduces a new class of direct interconnection networks called the hierarchical Multidimensional Directed Cycles Ensemble (hMDCE). Its suitability for massively parallel systems is discussed. The network is evolved from the Multidimensional Directed Cycles Ensemble (MDCE) network, where each node is substituted by lower-level sub-networks. The new network addresses some serious problems caused by the increasing scale of parallel systems, such as longer latency, limited throughput and high implementation cost. This paper first introduces the MDCE network and then presents and examines in detail the hierarchical MDCE network. Bisection bandwidth of hMDCE is considerably reduced from its ancestor MDCE and the network performs significantly higher throughput and lower latency under some practical implementation constraints. The gate count and delay time of the compiled circuit for the routing function are insignificant. These results reveal that the hMDCE network is an important candidate for massively parallel systems interconnection.

We proposed a graphical user interface (GUI) that provides users with multimedia information, including dynamic images. On the Internet, there are many WWW browsers that read the Hypertext Markup Language (HTML). As various browsers extend the HTML tags and attributes independently to expand and/or improve layout, the HTML compatibility between browsers is lost. We have developed a WWW browser to solve this problem. Our browser presents all multimedia information, including text, images, and dynamic images as a block and renders them without the need to extend the HTML specifications. It independently interprets and draws HTML objects using a layout manager. It has a layout rule, and manages the hierarchical data structure and the block data of HTML documents. This browser also allows layout-rule changes. The layout manager efficiently displays information while checking the available display area size. The structure of this browser is such that the portion that manages the formatting of the document is separated from the portion that displays the individual parts. In this browser, the layout rule allows text to be placed around an image without the need to modify the existing HTML contents. It is also relatively easy to change the presentation of multiple screens, such as a two-page book-like layout or the conventional single-page scroll-bar format by changing the layout rule. The incorporation of media decoders into the browser enables the displaying of various multimedia information, such as sounds, pictures, and moving images.

The up and coming multimedia services are based on real-time high-speed networks. For efficient operation of such services, real-time and precise network management is essential. In this paper, we show that presently available MIB designs are severely inadequate to support real-time network management. We point out and analyze the management constraints and bottlenecks. The concept of quality of management of management information is introduced and its importance in practical network management is discussed. We have proposed a new MIB architecture that will raise the quality of management information to meet the requirements of managing high-speed networks and multimedia services. Experimental results from a prototype implementation of the new MIB architecture are presented.

In this paper, quantization method which can keep the phase and gain characteristics of a reference filter is proposed. The proposed method uses a genetic algorithm and a simulated annealing algorithm. The objective function used in this method is described with two kinds of weighting functions for identifying the phase and gain characteristics respectively. Therefore, the quantization accuracy on the gain characteristic is independent of the accuracy on the phase characteristic. Further, the proposed algorithm can be applied to any types of filters, because the chromosome expresses only their coefficients values. The efficiency of the proposed algorithm is verified by some experiments.

This paper presents the results of a simulation study of blocking and non-blocking switching for hierarchical ring networks. The switching techniques include wormhole, virtual cut-through, and slotted ring. We conclude that slotted ring network performs better than the more popular wormhole and virtual cut-through networks. We also show that the size of the node buffers is an important parameter and that choosing them too large can hurt performance in some cases. Slotted rings have the advantage that the choice of buffer size is easier in that larger than necessary buffers do not hurt performance and hence a single choice of buffer size performs well for all system configurations. In contrast, the optimal buffer size for virtual cut-through and wormhole switching nodes varies depending on the system configuration and the level in the hierarchy in which the switching node lies.

This paper proposes new algorithms for diagnosing (detection, identification and location) baseline multistage interconnection networks (MIN) as one of the basic units in a massively parallel system. This is accomplished in the presence of single and multiple faults under a new fault model. This model referred to as the geometric fault model, considers defective crossing connections which are located between adjacent stages, internally to the MIN (therefore, a fault corresponds to a physical bridge fault between two connections). It is shown that this type of fault affects the correct geometry of the network, thus requiring a different testing approach than previous methods. Initially, an algorithm which detects the presence of bridge faults (both in the single and multiple fault cases), is presented. For a single bridge fault, the proposed algorithm locates the fault except in an unique pathological case under which it is logically impossible to differentiate between two equivalent locations of the fault (however, the switching element affected by this fault is uniquely located). The proposed algorithm requires log2 N test vectors to diagnose the MIN as fault free (where N is the number of input lines to the MIN). For fully diagnosing a single bridge fault, this algorithm requires at most 2 log2 N tests and terminates when multiple bridge faults are detected. Subsequently, an algorithm which locates all bridge faults is given. The number of required test vectors is O(N). Fault location of each bridge fault is accomplished in terms of the two lines in the bridge and the numbers of the stages between which it occurs. Illustrative examples are given.

The use of high-performance portable computers has become widespread. It is expected that many people will carry large amounts of multimedia information in these portable computers. In face-to-face communication, however, few systems are capable of exchanging multimedia information. Previously, we developed the Nomadic Collaboration Support System, which supports face-to-face communication through conversation and the distribution of documents. The system makes it possible for each participant in face-to-face communication to distribute electronic documents to other participants and edit them synchronously. However, it is often impossible for participants to obtain suitable amounts of information during face-to-face communication because of the difficulty in tailoring the documents for each participant. In this paper, we propose a technique to exchange hypertext documents on the Nomadic Collaboration Support System, which will allow each participant to obtain the most suitable amount of information possible from the distributor without his tailoring documents for each participant.

We develop a simulation environment for designing and examining a neural network model at the network level. The aim of our research is to enable researchers investigating neural network connective models to save time by being equipped with a graphical user interface and database of the network models. This environment consists of three parts: (1) the kernel of the simulation system, (2) NNDBMS (Neural Networks DataBase Management System), and (3) a system for displaying simulation results in various ways.

Communication latency is central to multiprocessor design. This study presents the design principles of the EM-X distributed-memory multiprocessor towards tolerating communication latency. The EM-X overlaps computation with communication for latency tolerance by multithreading. In particular, we present two types of hardware support for remote memory access: (1) priority-based packet scheduling for thread invocation, and (2) direct remote memory access. The priority-based scheduling policy extends a FIFO ordered thread invocation policy to adopt to different computational needs. The direct remote memory access is designed to overlap remote memory operations with thread execution. The 80-processor prototype of EM-X is developed and is operational since December 1995. We execute several programs on the machine and evaluate how the EM-X effectively overlaps computation with communication toward tolerating communication latency for high performance parallel computing.

A mesh spiral network (MSnet) and a mesh random (MRnet) are proposed. The MSnet consists of the 2-D torus and bypass links that keep the degree at six. The MRnet consists of the 2-D torus and random bypass links that keep the degree at six. The diameter and the average distance are calculated by using a computer program. The cost of the MSnet is slightly higher than that of the de Bruijn graph, and is about the same as the Star graph. The cost of the MRnet is better than that of the de Bruijn graph. The MSnet is proven to be maximally fault-tolerant. The upper bound of the MRnet size is also discussed.

The ringing occurred in the step response causes an undesirable stripe pattern in TV signals. A simultaneous approximation with both the frequency and the step response is required in the designing filter which is used in the image signal processing in order to prevent the ringing. The wellknown Remez algorithm for designing FIR filters approximates the response only in the frequency domain. As the result, the filters designed by this algorithm causes the large ringing in the step response. In this paper, we propose the method of design for FIR filters with minimum amplitude in the stopband, under the condition that the step response has no ringing and the prescribed rise characteristics. For this end, we use the constrained successive projections method.

This paper proposes fast FIR digital filter structures using the minimal number of adders. Filter coefficients are expressed with canonic signed digit (CSD) code and Hartley's technique is used to minimize the number of adders and subtractors. The proposed filters implemented as wired logic are fast because the structure having the shortest critical path is selected. Two algorithms are given to obtain such fast structures. In many examples the critical path length of the filter structures obtained using the proposed method is equal to that of the conventional CSD structures. This paper also presents a new design method of FIR filters using the mixed integer programming (MILP). Utilization of common expressions in Hartley's technique widens the CSD coefficient space. Thus the MILP may lead to better frequency responses. Superior frequency responses are actually obtained in many simulations.

This paper presents a new method for designing IIR Nyquist filters with zero intersymbol interference. It is shown that IIR Nyquist filters with zero intersymbol interference have some constraints on frequency response, i.e., both magnitude and phase error in passband are dependent on stopband error. Therefore, the frequency response is required to optimize only in stopband. The proposed procedure is based on the formulation of an eigenvalue problem by using Remez multiple exchange algorithm in stopband. Then, the filter coefficients can be computed by solving the eigenvalue problem, and the optimal solution with equiripple stopband response is easily obtained by applying an iteration procedure. The proposed procedure is more computationally efficient than the conventional methods.

In this paper the normalized lease mean square (NLMS) algorithm based on clipping input samples with an arbitrary threshold level is studied. The convergence characteristics of these clipping algorithms with correlated data are presented. In the clipping algorithm, the input samples are clipped only when the input samples are greater than or equal to the threshold level and otherwise the input samples are set to zero. The results of the analysis yield that the gain constant to ensure convergence, the speed of the convergence, and the misadjustment are functions of the threshold level. Furthermore an optimum threshold level is derived in terms of the convergence speed under the condition of the constant misadjustment.

An image obtained by ultrasonic medical equipment is poor in quality because of speckle noise, that is caused by the quality of ultrasonic beam and so on. Thus, it is very difficult to detect internal organs or the diseased tissues from a medical ultrasonic image by the processing, which is used only gray-scale of the image. To analyze the ultrasonic image, it is necessary to use not only gray-scale but also appropriate statistical character. In this paper, we suggest a new method to extract regions of internal organs from an ultrasonic image by the discrimination function. The discrimination function is based on gray-scale and statistical characters of the image. This function is determined by using parameters of the multi-dimensional autoregressive model.

In retrieving information from databases widely distributed in a network, the first thing to do is to search and find the database where the required information is stored. We call this the information searches rather than the retrievals. In this paper, we present a search and retrieval method for multimedia information, especially images. First, we formalize the general elements of information search and introduce a new search concept based on entropy reduction. Next, we discuss recent new technologies for image retrieval and introduce a new image retrieval system called VideoReality. Third, we present several methods of searching in the network- for example, the Internet robot TITAN, and a new search method for images distributed in the network that is based on the hierarchical structure of image retrieval. Finally, we discuss the network control and design concepts appropriate for information search and retrival.