The effects of α-particle-induced parasitic bipolar current on soft errors in submicron 6-transistor SOI SRAMs were numericaly studied. It was shown that the bipolar current induces soft errors and that there exists a critical quantity which determines the soft error occurrence in the SOI SRAMs. Simulated soft error rates were in the same order as those for bulk SRAMs.

Three dimensional model based coding methods are proposed as next generation image coding methods. These new representations need 3D reconstruction techniques. This paper presents a method that extracts the surfaces of static objects that occlude other objects from a spatiotemporal image captured with straight-line camera motion. We propose the concept of occlusion types and show that the occlusion types are restricted to only eight patterns. Furthermore, we show occlusion type pairs contain information that confirms the existence of surfaces. Occlusion information gives strong cues for segmentation and representation. The method can estimate not only the 3D positions of edge points but also the surfaces bounded by the edge points. We show that combinations of occlusion types contain information that can confirm surface existence. The method was tested successfully on real images by reconstructing flat and curved surfaces. Videos can be hierarchically structured with the method. The method makes various applications possible, such as object selective image communication and object selective video editing.

Time-critical-communication, which should guarantee a time limit of a communication service is getting important in multimedia and factory automation fields. This paper proposes an IP-based protocol, Network Protocol with Performance (NPP) to provide the advanced best-effort service which takes a time constraint into account for real-time applications on the Internet. NPP uses the packet-scheduling function to make an effort to guarantee time constraints. Packet-scheduling algorithm chooses a packet in a NPP queue by a precedent level and a time constraint of each packet. We also discuss an application of NPP to multimedia communication system, and investigate performance of NPP by simulation.

In order to display complicated virtual spaces in real time, such as spaces consisting of a dynamic natural scenery, we earlier proposed a method for simplifying the shape data of 3-D trees whereby the amount of shape data is efficiently reduced. The method generates tree shapes based on a fractal model according to the required level of details (LOD). By using a texture-mapping technique, we experimentally showed that our method can display 3-D tree images with allowable image quality in real time. However, methods for controlling the LOD of 3-D tree shapes in virtual spaces have yet to be discussed. In this paper, quantitative evaluations were made on the effect of a data simplification method employing such visual properties as resolution difference between the central vision and peripheral vision. Results showed that it is possible to display a complicated scene containing many trees in real time by controlling the LOD of tree shapes in the virtual space considering such visual properties. Furthermore, so that reality can be added to the virtual space, we consider that it is important to display the natural sways of wind-blown trees and plants in real time. Therefore, we propose a method for generating sway data for simplified tree shape data based on a simple physical model, in which each branch is connected to several other branches by springs, and also a new texture-mapping technique for rendering simplified tree shapes, making it appear as if the shapes have a high LOD. Finally, we show some examples of images of trees generated in real time by using our method, in which many trees exist and sway due to wind.

Neural network hardware using time-shared bus and integer representation architecture has already been fabricated and reported from the design viewpoint. However, nothing related to performance evaluation of hardware has yet been presented. Computation-speed, scalability and learning accuracy of hardware are evaluated theoretically and experimentally using a Back Propagation (BP) algorithm. In addition, a mirror-weight assignment technique is proposed for high-speed computation in the BP. NETTalk, an English-pronunciation-reasoning task, has been chosen as the target application for the BP. In the experiment, recently-developed neuro-hardware based on the above architecture and its parallel programming language are used. An outline of the language is described along with BP programming. Mirror-weight assignment allows maximum speed at 55.0 MCUPS (Million Connections Updated Per Second) using 256 neurons in the hidden-layer (numbers of neurons in input-and output-layers are fixed at 203 and 26 respectively in NETTalk). In addition, if scalability is defined as a function of the number of neurons in the hidden-layer, the machine retains high scalability at 0.5 if such a maximum speed needs to be used. No degradation in learning accuracy occurs when experimental results computed using the neuro-hardware are compared with those obtained by floating-point representation architecture (workstation). The experiment indicates that the present integer representational design of the neuro-hardware is sufficient for NETTalk. Performance has been evaluated theoretically. For evaluation purposes, it is assumed that most of the total execution-time is taken up by bus cycles. On the basis of this assumption, an analytical model of computation-speed and scalability is proposed. Analytical predictions agreed well with experimental results.

This paper describes methods in which natural language is used to describe video contents, knowledge of which is needed for intelligent video manipulation. The content encoded by natural language is extracted by a language analyzer in the form of subject-centered dependency structures which is a language-oriented structure, and is combined in an incremental way into a single structure called a multi-path index tree. Content descriptors and their inter-relations are extracted from the index tree in order to provide a high speed retrieval and flexibility. The content-based video index is represented in a two-dimensional structure where in the descriptors are mapped onto a component axis and temporal references (i.e., video segments aligned to the descriptors) are mapped onto a time axis. We implemented an experimental image retrieval systems to illustrate the proposed index structure 1) has superior retrieval capabilities compare to those used in conventional methods, 2) can be generated by an automated procedure, and 3) has a compact and flexible structure that is easily expandable, making an integration with vision processing possible.

The finite-difference beam-propagation method is applied to the analysis of a bent step-index slab optical waveguide. The results obtained in the rectangular coordinates with a modified index profile are compared with those in the cylindrical coordinates with a real index profile. It is found that the attenuation constant for TMo mode is larger than that for TEo mode. The polarization dependence of bending loss is negligible, provided the refractive index difference is less than 2%.

The most troublesome problem in automated X-ray mask inspection is how to exactly determine the threshold level for extracting the pattern portions of each scanning electron microscopic (SEM) image. An exact determination is difficult because the histogram shows, in most cases, a complicated multi-modal pattern and the true threshold level often varies with each successive image. This paper presents a novel thresholding approach for segmenting SEM images of X-ray masks. In this approach, the shape of the histogram of each image is iteratively analyzed until a threshold value minimizing the cost of the correspondence with a reference histogram and satisfying criteria for determining thresholds is obtained. This new approach is used in an automated inspection system. When the input image resolution is set to 0.05µm/pixel, experiments confirm 0.1µm defects are unfailingly detected.

This paper presents the computer simulation results on frequency reuse efficiency and soft handoff statistics in the CDMA forward link according to path loss and cell loading. The soft handoff threshold effect on the handoff statistics is also evaluated. The frequency reuse efficiency is not a fixed value but varying as function of distance from the home cell, path loss slopes, and cell loading. The total soft handoff pecentile ranges from 0.0 to 64.9 according to cell loading, even if path loss slope is constant.

Full-search block-matching motion estimation is a popular method to reduce temporal redundancies in video sequence. Due to its excessive computational load, parallel processing architectures are often required for real-time processing. One of the architectures is Hsieh's architecture based on systolic array processor and shift register arrays. Serial input characteristic of his scheme can reduce the number of pixel inputs to one, at the expense of significantly increasing the initialization time. This paper presents a modified and generalized Hsieh's architecture to reduce the initialization time. The proposed architecture can easily control data flows by rearranging shift register arrays and input-pin counts by using multiplexers on input stage, while retaining good properties of Hsieh's. The proposed architecture has the following advantages: (1) it allows controllable data inputs to save the pin counts, (2) it is flexible to the dimensional change of the search area via simple control, (3) it can operate in real time for video conference applications, and (4) it has simple and modular structure which is quite suitable for VLSI implementation. For verification of the proposed architecture, VHDL simulations are performed and some results are given.

For a fuzzy control of manipulated variable so as to match a required output of a plant, tuning of fuzzy rules are necessary. For its purpose, various methods to tune their rules automatically have been proposed. In these method, some of them necessitate much time for its tuning, and the others are lacking in the generalization capability. In the fuzzy control by the steepest descent method, a use of piecewise linear membership functions (MSFs) has been proposed. In this algorithm, MSFs of the premise for each fuzzy rule are tuned having no relation to the other rules. Besides, only the MSFs corresponding to the given input and output data for the learning can be tuned efficiently. Comparing with the conventional triangular form and the Gaussian distribution of MSFs, an expansion of the expressiveness is indicated. As a result, for constructing the inference rules, the training cycles can be reduced in number and the generalization capability to express the behavior of a plant is expansible. An effectiveness of this algorithm is illustrated with an example of a parallel parking of an autonomous mobile robot.

This paper proposes a new approach for inputting handwritten Distribution Facility Drawings (DFD) and their maps into a computer automatically by using the Facility Management Database (FMD). Our recognition method makes use of external information for drawing/map recognition. It identifies each electric-pole symbol and support cable symbol on drawings simply by consulting the FMD. Other symbols such as transformers and electric wires can be placed on drawings automatically. In this positioning of graphic symbols, we present an automatic adjustment method of a symbol's position on the latest digital maps. When a contradiction is unsolved due to an inconsistency between the content of the DFD and the FMD, the system requests a manual feedback from the operator. Furthermore, it uses the distribution network of the DFD to recognize the street lines on the maps which aren't computerized. This can drastically reduce the cost for computerizing drawings and maps.

For similarity methods to work well, the image must be blurred before being input. However, the relationship between the blurring operation and the similarity is not fully understood. To solve the problem of this relationship, in this paper, the effect of blurring is investigated by expressing figure f(x) in the form of the sum of higher derivatives of f (x,σ), and then a simple similarity between figures was mathematically formulated in terms of the relation between visual patterns. By modifying this formulation, we propose pluralized simple similarity to increase the allowance in different view of multiple similarity. The similarity maintains higher allowance without any discernible loss of distinguishing power. We verify the effectiveness of the pluralized simple similarity throughout some experiments.

Fundamental microwave key devices used in achieving compact mobile/portable telephones (raidio units) are discussed. The historical development flow of the systems and radio units are introduced, with respect to the 800-/900-MHz and 1.5-GHz Japanese cellular radio systems. The design concept of the developed radio units is briefly described. Tehnical requirements for RF circuits are reviewed and the developed key devices are practically applied to the circuits. Key factors in the requirements are also shown. Finally. future trends fro the key devices are surveyed from the stand point of achieving a smaller and more light weight pocket radio unit.

Handprinted Kanji character recognition was the most important research topic for 1980s. Today there are several commercial products of handprinted Kanji OCR, but there are many unsolved problems. In this paper three types of research approach are focused for handprinted Kanji character recognition. The first approach is directional pattern matching, which is generally applied to handprinted Kanji character recognition. The second approach is potential field feature extraction, which activated Kanji character recognition research in the early stage of research. The third approach is shape matching. This paper surveys these research approaches, and both contributions and problems of them are discussed.

Among various characters invented by the human being ,Kanji (Chinese character) is outstanding in its diversity and complexity, in contrast to Roman alphanumerics. So machine recognition of handwritten characters requires particular technics. This paper concerns commercially available optical character readers (OCRs) and the recognition techniques using therein. Methods of character recognition is classified the pattern types and the method of extracting features, to discuss the present states of the character recognition. In regard to the structural analysis, the proposed techniques are classified and discussed in accordance with the extraction method of line segment and axial correlation. Finally, various techniques are compared with one another by using a common database, so as to understand the present states of character recognition and to discuss the technical trends.

This paper describes advances in the study of handwritten Kanji character recognition mainly performed in Japan. The research focus has shifted from the investigation of the possibility of recognition by the stroke structure analysis method to the study of the feasibility of recognition by the feature matching methods. A great number of features and their extraction methods have been proposed according to this approach. On the other hand, studies on pattern matching methods of recognizing Kanji characters using the character pattern itself have been made. The research efforts based on these two approaches have led to the empirical fact that handwritten Kanji character recognition would become more effective by paying greater attention to the feature of directionality. Furthermore, in an effort to achieve recognition with higher precision, active research work has been carried out on pre-processing techniques, such as the forced reshaping of input pattern, the development of more effective features, and nonlinear flexible matching algorithms. In spite of these efforts, the current character recognition techniques represent only a skill of guessing characters" and are still on an insufficient technical level. Subsequent studies on character recognition must address the question of how to understand characters".

We proposed a new thchnique using saw wave modulation light to measure the thermal diffusivity of a transparent adhesive by photoacoustic microscope. In this technique, the time required for the measurement of it can be reduced by one-fifth compared with that of a conventional method.

Processor networks connected by buses have attracted considerable attention. Since a reconfigurable array is more powerful than a PRAM and more practical, it becomes the focus of attention. The Processor Array with Reconfigurable Bus System (PARBS) and the Reconfigurable Multiple Bus Machine (RMBM) are both models of parallel computation based on reconfigurable bus and processor array. The PARBS is a processor array that consists of processors arranged to a 2-dimensional grid with a reconfigurable bus system. The RMBM is also made of processors and reconfigurable bus system, but the processors are located in a row and the number of processors and the number of buses are independent of each other. Four versions of RMBM has been proposed and Extended RMBM (E-RMBM) is regarded as the most powerful one among them. In this paper, we describe that a PARBS of size N M can be simulated in constant time by a E-RMBM of 4NM processors, M + 3 buses and 1 read buffer, and that a E-RMBM of P processors, B buses and D read buffers can be also simulated in constant time by a PARBS of size B P. A PARBS or RMBM that solves a computational problem of size n is polynomially bounded iff the product of the number of processors and buses and red and write ports is O (nc), for some constant c. When a PARBS is polynomially bounded, the E-RMBM which simulates it is also polynomially bounded, and vice versa.

Both available bit rate (ABR) service and unspecified bit rate (UBR) service with early packet discard (EPD) schemes have been considered for supporting data applications in ATM networks. Since transmission control protocol (TCP) is perhaps the most widely used transport layer protocol in existing data networks, the performance of TCP over ATM using ABR service and UBR service with EPD schemes is of great interest to ATM equipment vendors and service providers. In this paper, we present a simulation study of this interesting issue in a LAN environment using some benchmark network configurations proposed in the ATM Forum. Our simulation results show the following: (1) With UBR service and EPD schemes, TCP suffers significant performance degradation in terms of fairness and requires relatively large switch buffer even with a small number of active virtual connections over a LAN configuration, and (2) for the same set of network configurations and with ABR service using explicit rate feedback schemes, TCP achieves good performance in terms of fairness and link utilization, and requires relatively small switch buffer.