In this paper, we show that the conventional BCH codes can be better than the AG codes when the number of check symbols is relatively small. More precisely, we consider an AG code on Cab whose number of check symbols is less than min {g+a, n-g}, where n and g denote the code length and the genus of the curve, respectively. It is shown that there always exists an extended BCH code, (i) which has the same designed distance as the Feng-Rao designed distance of the AG code and the code length and the rate greater than those of the AG code, or (ii) which has the same number of check symbols as that of the AG code, the designed distance not less than that of the AG code and the code length longer than that of the AG code.

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.

A practical structural representation of a segmented image is presented. The practicalness is defined according to whether or not the representation can be directly generated from its corresponding segmented image. Two structural representations have been proposed in the literature. They are hierarchical structure and relational graph. Because they are defined totally on the basis of human perception, neither of the representations can be directly generated from the corresponding segmented image. The structural representation described in this paper, however, is based on the relations among pattern primitives and generated by applying some human-oriented constraints.

To develop human interface for virtual environment, we have constructed a tensed strings based interface device called SPIDAR, which allow us to manipulate virtual object directly just like in real space. SPIDAR can both measure the movement of user's finger tip and offer force display. Since proper force feedback comes out of the proper position measurement, in this paper, we will analyze the possible reasons that may cause position measurement error, and propose an algorithm which can revise the error and improve position measurement precision.

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.

Here we investigate the unique advantages of our proposed Virtual Space Teleconferencing System (VST) in the area of multimedia teleconferencing, with emphasis to facial emotion transmission and recognition. Specially, we show that this concept can be used in a unique way of communication in which the emotions of the local participant are transmitted to the remote party with higher recognition rate by enhancing the emotions using some intelligence processing in between the local and the remote participants. In other words, we can show that this kind of emotion enhanced teleconferencing systems can supersede face to face meetings, by effectively alleviating the barriers in recognizing emotions between different nations. Also in this paper we show that it is better alternative to the blurred or mosaiced facial images that one can find in some television interviews with people who are not willing to be exposed in public.

This paper is concerned with bandwidth reservation for circuit groups which handle calls requesting asymmetric forward and backward multi-connections. A model of circuit group with sub-group configuration is treated, and two types of the bandwidth reservation schemes for the model are studied in this paper. One is a global scheme with monitoring the whole circuit group, and the other is a local scheme with monitoring each sub-group independently. The problems of optimizing the reservation parameters are formulated, and optimization methods for the problems are proposed. Numerical example are presented, and effectiveness of the reservation schemes with using the optimized parameters is numerically examined.

One of the important properties of multihop network is the mean internodal distance to evaluate the transmission delay, and the connective semi-random network achieves smaller mean internodal distance than other networks. However, the results are shown only by computer simulation and no theoretical analysis is investigated. Moreover, the network connective probability of the connective semi-random network is relatively small. In this paper, we propose the restricted connective semi-random network whose network connective probability is larger than that of the conventional connective semi-random network. And we theoretically analyze the mean internodal distance and the network connective probability of these two networks. It is shown that if the restriction is loose, the mean internodal distance of our model is almost the same as that of the conventional model, whereas the network connective probability of our model is larger than that of the conventional model. Moreover, the theoretical analyzed results of the mean internodal distance agree well with the simulated results in the conventional model and our model with small restriction.

In this paper, a simple method to investigate the dynamics of continuous-time neural networks based on the force (kinetic vector) derived from the equation of motion for neural networks instead of the energy function of the system has been described. The number of equilibrium points and limit cycles of one-dimensional neural networks with the asymmetric cyclic connection matrix has been investigated experimently by this method. Some types of equilibrium points and limit cycles have been theoretically analyzed. The relations between the properties of limit cycles and the number of connections also have been discussed.

This paper describes the results obtained of a prototype system, VeriProc/1, based on an algorithm we first presented in [13] which can prove the correctness of pipelined processors automatically without pipeline invariant, human interaction, or additional information. No timing relations such as an abstract function or β-relation is required. The only information required is to specify the location of the selectors in the design. The performance is independent of not only data width but also memory size. Detailed analysis of CPU time is presented. Further, don't-care forcing using additional data easily prepared by the user can improve performance.

A verification is made on the accuracy of Radar-AMeDAS precipitation, which represents hourly precipitation over the Japanese Islands and the surrounding sea area with a spatial resolution of 5km using data from 5cm conventional radars, 10cm Fujisan Radar, and Automated Meteorological Data Acquisition System (AMeDAS) raingauge network. By comparing with data from a very dense raingauge network of the Tokyo Metropolitan Government, it is found that 1) Radar-AMeDAS precipitation shows good agreement if a positioning error of one pixel of 5km square is allowed 2) Radar-AMeDAS precipitation represents almost the average of raingauge measurements in the 5km square for most of the precipitation caused by a large scale disturbance, and 3) Radar-AMeDAS precipitation is close to the maximum raingauge measurement in the pixel when precipitation is extremely localized such as thunderstorms or showers. Radar-AMeDAS precipitations are compared also with AMeDAS measurements statistically with respect to the appearance rates, that is (total number of pixels where specific intensity is observed) / (total number of all pixels), for different precipitation intensities. The rate of Radar- AMeDAS precipitation shows excellent agreement with that of AMeDAS if radar echoes are observed at the altitude lower than 2km. Since Radar- AMeDAS precipitation on land sometimes represents the maximum of precipitation in a pixel for the purpose of unfailingly detecting extremely localized severe precipitation, it shows a high appearance rate at high precipitation intensity than AMeDAS, which is considered to represent statistically the average of a pixel. As a result, in estimating areal rainfall amounts, Radar- AMeDAS precipitation overestimates AMeDAS measurement by 8% at 5mm/h and by 12% at 40mm/h. Radar- AMeDAS precipitation over the sea, with no local calibration by AMeDAS and with little influence of orography, is 2% weaker in intensity than AMeDAS at 10mm/h, and 12% at 40mm/h.

A maximum diameter (Dmax) of raindrop should be assumed when rainfall rate (R) is estimates from the differential reflectivity (ZDR) and the horizontal reflectivity (ZH) measured with dual-polarization radar. If the assumed Dmax is different from actual Dmax, the estimated R contains errors. Using distrometer data, it was found that ZDR correlates with Dmax, and it was verified that when Dmax is adaptively determined by an empirical relationship between ZDR and Dmax, errors in estimated R can be reduced.

Multimedia Database Systems as the tool to extract and generate additional values from multimedia 'Contents' are discussed in this paper with putting emphasis on the mediator functions between users and contents. Firstly, we discuss about 'what to do' from the view point of four promising contents sources: 'on the network,' 'in the digital broadcasting' 'in the library' and 'in the real world.' From this view pont, four types of multimedia database systems are defined. 'What to do' for each database system is also discussed. Two concrete multimedia database systems with unique mediator functions, stream-type multimedia database platform GOLS and the intelligent access and authoring system using multiple media synchronization are proposed with experimental evaluation results and concrete multimedia database applications.

This paper discusses how to derive message sequence charts (MSCs) from a set of state transition descriptions. Recently, MSC notation has received much attention in the communications software field because it graphically shows system global behavior, So MSC handling techniques are being widely studied. These studies have recommended the design a system by a set of formal MSCs in the early stages of development and then to convert them into state transition descriptions. However, it is difficult to apply those results to existing communications software products. This is because these systems are designed based on state transition descriptions and there are no formal MSCs for them. In this paper, we propose a method of deriving MSCs based on optimized reachability analysis. This method generates MCSs that avoid state explosion. A case study using Q.931 protocol shows the feasibility of this method.

A CMOS fully balanced current-mode filter is presented. A fully balanced current-mode integrator which is the basic building block is implemented by adding a very simple common-mode-rejection mechanism to fully differential one. The fully balanced operation can eliminate even order distortion, which is one of the drawbacks in previous continuous current-mode filter. Moreover, the additional circuit can work as not only common-mode-rejection mechanism but also Q-tuning circuit which compensates lossy elements due to finite output impedance of MOS FET. A prototype fifth-order low-pass lad-der filter designed in a standard digital 0.8µm CMOS process achieved a cut-off frequency (fC) of 100MHz; fC was tunable from 75MHz to 120MHz by varying a reference bias current from 50µA to 150µA. Using a single 3V power supply with a nominal reference current of 100µA, power dissipation per one pole is 30mW. The active filter area was 0.011mm2/pole and total harmonic distortion (THD) was 0.73 [%] at 80MHz, 80µA amplitude signal. Furthermore, by adjusting two bias currents, on chip automatic both frequency and Q controls are easily implemented by typical tuning systems, for example master-slave tuning systems [1].

A 2V/120 ns flash EEPROM embedded in a microcontroller has been fabricated in 0.8 µm double-metal CMOS process technology with a simple stacked gate memory cell. To achieve low voltage and high speed operation, novel circuit technology and architecture; (a) PMOS-precharging NMOS-self-boost word line circuit with a higher voltage selector, (b) new erase algorithm for reverse operation, (c) column gate boost circuit, (d) hard-verify mode for replacing weak cells, (e) efficient redundancy of row and column lines, have been developed. A 512 kb flash EEPROM core chip incorporating these circuit techniques and architecture operate at 1.8 V and accesses data in 120 ns at 2 V and 70.

The MU radar of Japan is one of important candidates for providing accurate ground truth for the TRMM precipitation radar. It can provide the dropsize distribution data together with the background atmospheric wind data with high accuracy and high spatial resolution. Special observation scheme developed for TRMM validation using the MU radar is described, and preliminary results from its test experiment are shown. The high-resolution MU radar data are also used in numerical simulations to validate the rain retrieval algorithm for the TRMM PR data analysis. Among known sources of errors in the rain retrieval, the vertical variability of the dropsize distribution and the partial beam-filling effect are examined in terms of their significance with numerical simulations based on the MU radar data. It is shown that these factors may seriously affect the accuracy of the TRMM rain retrieval, and that it is necessary to establish statistical means for compensation. However, suggested means to improve the conventional α-adjustment method require careful treatment so that they do not introduce new sources of errors.

A blind equalization algorithm which makes use of the Stop" region of the Stop-and-Go algorithm is proposed. By adaptively updating the tap weights at the Stop region as well, it is intended to improve the convergence property of the Stop-and-Go algorthm. The performance of the proposed algorithm is compared with the conventional Stop-and-Go algorithm using various communication channels. Simulation results indicate the improvement of the convergence speed while maintaining or possibly lowering the residual error.

This paper investigates the performance of an integrated voice and data transmission protocol that can be used in mobile communication networks, e.g. mobile cellular and LEOGEO satellite networks. Voice and data are concentrated at place such as base station in a cellular network. Time sensitive voices are supported by the concentrator in the manner of TDMA. Loss sensitive data are collected, stored, and transmitted using idle TDMA slots. Data users transmit data to the concentration point using ALOHA protocol. Characterization of data arrivals to the concentrator is done by the method of moment matching. The emphasis of this study is on the data performance in terms of packet loss rate, average buffer occupancy, and mean packet waiting time. It is demonstrated through numerical examples that a buffer of reasonable size is good enough to offer satisfactory performance. The analysis is also validated by computer simulations.

A structural active-object system (SAOS) is a transition-based object-oriented system suitable for rapid development of hardware logic simulators. A SAOS consists of a collection of interacting structural active objects (SAOs), whose behaviors are determined by the transition statements provided in their class definitions. Furthermore, SAOs can be structurally and hierarchically composed from their component SAOs like hardware components. These features allow SAOs to model components for circuit simulation more naturally than passive objects used in ordinary object-oriented programming. Also, we can easily create new kinds of components by using the inheritance mechanism. Executions of transition statements may be event-and/or time-driven, and hence digital, analog, and mixed-mode simulation is possible. Prototype simulation programs with graphical user interfaces have been developed as SAOS programs for digital, analog, and mixed-mode circuit simulation.