The relation between the radiation pattern and the dimension of the conducting box for a portable telephone is illustrated both theoretically and experimentally. The Galerkin-moment method using the Fourier series expansion for the surface current of the conducting box, which has a great advantage of having a high accuracy, is employed to obtain the radiation pattern. As an example of antennas, a quarter-wavelength monopole antenna having a sinusoidal current distribution is used. As a result, it is pointed out that the radiation pattern of a monopole antenna mounted on the box tends to tilt in a lower direction both in theory and in experiment as well. The relation between the radiation pattern and the location of the monopole antenna is also described. An asymmetrical, or distorted pattern is observed when the monopole antenna moves away from the center of the top plane.

We analyze the nonlinear dynamics of PLL from the "complex" singularity structure by introducing the complex time. The most important results which we have obtained in this work are as follow: (1) From the psi-series expansion of the solution, the local behavior in the neighbourhood of a movable singularity is mapped onto an integrable differential equation: the Ricatti equation. (2) From the movable pole of the Ricatti equation, a set of infinitly clustered singularities about a movable singularity is shown to exist for the equation of PLL by the multivalued mapping. The above results are interesting because the clustering and/or the fractal distribution of singularities is known to be a characteristic feature of the non-integrability or chaos. By using the method in this letter, we can present a circumstantial evidence for chaotic dynamics without assuming any small parameters in the equation of PLL.

This paper gives a systematic approach to generate a Markov chain by a discrete-valued auto-regressive equation, which is a a nonlinear auto-regressive equation having a discrete-valued solution. The power spectrum, the correlation function and the transition probability are explicitly obtained in terms of the discrete-valued auto-regressive equation. Some computer results are illustrated in figures.

We propose a recognition method for HMM using a simultaneous generative histogram. Proposed method uses the correlation between two features, which is expressed by a simultaneous generative histogram. Then output probabilities of integrated HMM are conditioned by the codeword of another feature. The proposed method is applied to isolated digit word recognition to confirm its validity.

In this article, the autocorrelation associative neural network that is one of well-known applications of neural networks is improved to extend its capacity and error correcting ability. Our approach of the improvement is based on the consideration that negative self-feedbacks remove spurious states. Therefore, we propose a method to determine the self-feedbacks as small as possible within the range that all stored patterns are stable. A state transition rule that enables to escape oscillation is also presented because the method has a possibility of falling into oscillation. The efficiency of the method is confirmed by means of some computer simulations.

This paper gives a model to explain one phenomenon found in the process of creative concept formation, i.e. the phenomenon that people often get trapped in some state where the mental world remains nebulous and sometimes suddenly make a jump to a new concept. This phenomenon has been qualitatively explained mainly by the philosophers but there have not been models for explaining it quantitatively. Such model is necessary in a new research field to study the systems for aiding human creative activities. So far, the work on creation aid has not had theoretical background and the systems have been built based only on trial and error. The model given in this paper explains some aspects of the phenomena found in creative activities and give some suggestions for the future systems for aiding creative concept formation.

A communication LSI Set for Automotive Body control systems such as power windows, power seats, and power doors based on an in-vehicle network have been developed. The main function of the LSI is to achieve an original automotive communication protocol. The LSI set makes it possible to build a new kind of automotive control system, and reduces the number of wiring harnesses and weight below those of the conventional automotive body electronics. The communications transmitters and receivers have been integrated on-chip, so the LSI needs several external discrete components such as resistors, capacitors, and diodes. This communications LSI offers the advantages of small size and high reliability of the electronic control unit based on an in-vehicle network.

The performances of BPNN (neural network trained by back propagation) and PCANN (neural network which computes principal component analysis) for ECG data compression have been investigated from several points of view. We have compared them with an existing data compression method TOMEK. We used MIT/BIH arrhythmia database as ECG data. Both BPNN and PCANN showed better results than TOMEK. They showed 1.1 to 1.4 times higher compression than TOMEK to achieve the same accuracy of reproduction (13.0% of PRD and 99.0% of CC). While PCANN showed better learning ability than BPNN in simple learning task, BPNN was a little better than PCANN regarding compression rates. Observing the reproduced waveforms, BPNN and PCANN had almost the same performance, and they were superior to TOMEK. The following characteristics were obtained from the experiments. Since PCANN is sensitive to the learning rate, we had to precisely control the learning rate while the learning is in progress. We also found the tendency that PCANN needs larger amount of iteration in learning than BPNN for getting the same performance. PCANN showed better learning ability than BPNN, however, the total learning cost were almost the same between BPNN and PCANN due to the large amount of iteration. We analyzed the connection weight patterns. Since PCANN has a clear mathematical background, its behavior can be explained theoretically. BPNN sometimes generated the connection weights which were similar to the principal components. We supposed that BPNN may occasionally generate those patterns, and performs well while doing that. Finally we concluded as follows. Although the difference of the performances is smal, it was always observed and PCANN never exceeded BPNN. When the ease of analysis or the relation to mathematics is important, PCANN is suitable. It will be useful for the study of the recorded data such as statistics.

This letter shows that VEPs can be easily measured by using color cards as the color stimulus, and that the responses evoked by a difference in chroma could be described largely by the value of the first principal component in principal component analysis.

The Traveling Salesman Problem (TSP) can be solved by a neural network using the coding scheme based on the adjacency of city in the tour. Using this coding scheme, the neural network generates a better solution than that using other coding schemes. We, however, often get the invalid solution consisting of some subtours. In this article, we propose a method of eliminating subtours using additional neurons. On the computer simulation it is shown that we get the optimum solution by means of taking only O(n2) additional neurons and trials.

We have developed an SIMD processor on a double-height VME board. We achieved a good balance between cost and performance by combining four identical gate-array LSIs in the processor array with a 16-bit degital signal processor (DSP), standard dynamic random-access memories (DRAMs) and other peripherals. The gate-array LSIs have 168-bit processing elements (PEs), each containing a one-bit processing block and a serial multiplier. This PE structure offers high-level bit processing capability and peak performance of 512 million operations per second (MOPS) for 8-bit multiply and accumulate operations. Effective performance of more than 300 MOPS for 8-bit array data processing is achieved by using an LSI structure tuned to the DRAM access rate, although the processing speed is reduced by the DRAM access bottleneck. The LSIs also have two unique additional hardware structures that speed up various array data processes. One is an inter-PE routing register array for supporting a transmission, rotation and memory access path. The other is a tree-structure network for propagating operations among PEs. With these cost-effective structures, the SIMD processor is expected to be widely used for two-dimensional data processing, such as image processing and pattern recognition.

A soft-decision decoding algorithm for binary linear block codes is proposed. This algorithm seeks to minimize the block error probability. With careful examinations of the first hard-decision decoded results, the candidate codewords are efficiently searched for. Thus, we can reduce the decoding complexity (the number of hard-decision decodings) and lower the block error probability. Computer simulation results are presented for the (23, 12) Golay code. They show that the decoding complexity is considerably reduced and the block error probability is close to that of the maximum likelihood decoder.

This paper describes a planning method for ATM networks. The method is based on evaluation of two design items, VC routing and VP routing, as well as on consideration of VPI constraints. In the evaluation, VC routing is compared with VP routing in separate case studies undertaken from the point of view of various parameters such as traffic volume, cost function and network scale. The results suggest the vertical relationship between VC and VP levels in optimally designed ATM networks. VC and VP network levels are then studied separately, and design methods are proposed for individual levels. In addition a perturbation method is proposed for the VC and VP routing use, whose optimum is varied as a function of the parameters described above. Evaluation results show the proposed perturbation method provides cost-effective networks.

In our preceding paper, I-ISMA (Idle Signal Multiple Access for Integrated services), a combination of ISMA and time reservation technique, was proposed to transmit an integrated voice and data traffic in third generation wireless communication networks. There, the channel capacity of I-ISMA was evaluated by the static analysis. To fully estimate performance of contention-based channel access protocols, however, we also need dynamic analysis to evaluate stability, delay, etc. Particularly, in systems concerning real-time voice transmission, delay is one of the most important performance measures. A six-mode model to describe an I-ISMA system is set up. With some assumptions for simplification, the dynamic behavior of the system is approximated by a Markov process so that the EPA (Equilibrium Point Analysis), a fluid approximation method, can be applied to the analysis. Then, numerical and simulation results are obtained for some examples. By means of the same analysis method and under the same conditions, the performance of PRMA is evaluated and compared briefly with that of I-ISMA.

A method for constructing a compact non-blocking, large matrix-size, optomechanical switch is proposed. It can be switched arbitrarily by disconnecting and reconnecting ferrules on the matrix board. A 250500, 25-mm-ferrule-pitch, 800W855D945H (mm) switch is fabricated. Although the space above the board is densely packed with many ferrule-terminated-fibers, because of the way in which they are arranged and the control of their length, there is no discernible excess loss due to fiber bending.

The design of a high speed self-routing network switch module is described. Clock distribution and timing design to achieve high-speed operation are considered. A 88-port self-routing Benes network switch prototype on multi-chip module is fabricated using 44-port space division switch LSIs. The switch module achieves a maximum measured clock frequency of 750MHz under switching operation. Resultant total throughput of the switch module is 12Gbit/s.

Space-time tradeoff is a very fundamental issue to design a fault-tolerant real-time (called responsive) system. Routing a message in large computer networks is efficient when each node knows the full topology of the whole network. However, in the hierarchical routing schemes, no node knows the full topology. In this paper, a tradeoff between an optimality of path length (message delay: time) and the amount of topology information (routing table size: space) in each node is presented. The schemes to be analyzed include K-scheme (by Kamoun and Kleinrock), G-scheme (by Garcia and Shacham), and I-scheme (by authors). The analysis is performed by simulation experiments. The results show that, with respect to average path length, I-scheme is superior to both K-scheme and G-scheme, and that K-scheme is better than G-scheme. Additionally, an average path length in I-scheme is about 20% longer than the optimal path length. On the other hand, for the routing table size, three schemes are ranked in reverse direction. However, with respect to the order of size of routing table, the schemes have the same complexity O (log n) where n is the number of nodes in a network.

The emerging discipline of responsive systems demands fault-tolerant and real-time performance in uniprocessor, parallel, and distributed computing environments. The new proposal for responsiveness measure is presented, followed by an introduction of a model for responsive computing. The model, called CONCORDS (CONsensus/COmputation for Responsive Distributed Systems), is based on the integration of various forms of consensus and computation (progress or recovery). The consensus tasks include clock synchronization, diagnosis, checkpointing scheduling and resource allocation.

A responsive network architecture is essential in future open distributed systems. In this paper, a framework that provides the foundations for a responsive network architecture for an internetworking environment is proposed. It is called the Virtually Separated Link (VSL) model. By incorporating this framework, communication of both data and control information can be completed in bounded time. Consequently, a protocol can initiate a recovery mechanism in bounded time, or allow an application to do the same. Its functionalities augment existing resource reservation protocols that support multimedia communication. An overview of a real-time network protocol that is based on this framework is also presented.

Responsive protocols are communication protocols which ensure timely and reliable recovery when error events occur. Protocol synthesis for design of responsive protocols is to derive a protocol specification based on a service specification. In the previous methods, if the service specification includes simultaneous transmission of primitives from a high layer to a low layer through different service access points, then the derived protocol specification includes protocol errors of unspecified reception caused by message collisions. Also, they only includes a recovery function such as retransmission of messages. This is not enough for recovery from abnormal states due to coordination loss. This paper extends a class of derived protocol specifications to include message collisions which usually occur in real communication protocols. Furthermore, this paper proposes a new method for synthesis of a responsive protocal specification derived from a service specification such that the derived protocol specification is free from protocol erros of unspecified receptions caused by message collisions and includes two recovery functions: message retransmission and checkpoint restart functions.