In this paper, we present simulation algorithms among enhanced mesh models. The enhanced mesh models here include reconfigurable mesh and mesh with multiple broadcasting. A reconfigurable mesh (RM) is a processor array that consists of processors arranged to a 2-dimensional grid with a reconfigurable bus system. The bus system can be used to dynamically obtain various interconnection patterns among the processors during the execution of programs. A horizontal-vertical RM (HV-RM) is obtained from the general RM model, by restricting the network topology it can take to the ones in which each bus segment must be along row or column. A mesh with multiple broadcasting (MWMB) is an enhanced mesh, which has additional broadcasting buses endowed to every row and column. We present two algorithms:1) an algorithm that simulates a HV-RM of size nn time-optimally in θ(n) time on a MWMB of size nn, and 2) an algorithm that simulates a RM of size nn in θ(log2 n) time on a HV-RM of size nn. Both algorithms use a constant number of storage in each processor. Furthermore, we show that a RM of size nn can be simulated in θ((n/m)2 log n log m) time on a HV-RM of size mm, in θ ((n/m)2 m log n log m) time on a MWMB of size mm (m < n). These simulations use θ((n/m)2) storage in each processor, which is optimal.

In order to improve the efficiency of the feature extraction of backpropagation (BP) learning in layered neural networks, model switching for changing the function model without altering the map is proposed. Model switching involves map preserving reduction of units by channel fusion, or addition of units by channel installation. For reducing the model size by channel fusion, two criteria for detection of the redundant channels are addressed, and the local link weight compensations for map preservation are formulated. The upper limits of the discrepancies between the maps of the switched models are derived for use as the unified criterion in selecting the switching model candidate. In the experiments, model switching is used during the BP training of a layered network model for image texture classification, to aid its inefficiency of feature extraction. The results showed that fusion and re-installation of redundant channels, weight compensations on channel fusion for map preservation, and the use of the unified criterion for model selection are all effective for improved generalization ability and quick learning. Further, the possibility of using model switching for concurrent optimization of the model and the map will be discussed.

Dynamical theory of cellular automata on groups is developed. Main results are non-Euclidean extensions of Sato and Honda's results on the dynamics of Euclidean cellular automata. The notion of the period of a configuration is redefined in a more group theoretical way. The notion of a co-finite configuration substitutes the notion of a periodic configuration, where the new term is given to it to reflect and emphasize the importance of finiteness involved. With these extended or substituted notions, the relations among period preservablity, injectivity, and Poisson stability of parallel maps are established. Residually finite groups are shown to give a nice topological property that co-finite configurations are dense in the configuration space.

The minimum mean-squared error (MMSE) linear detector has been proposed to successfully suppress the multiple access interference and mitigate the near-far problem in direct-sequence code-division multiple access communication systems. In the presence of unknown or time-varying channel parameters, the MMSE linear detector can be implemented by the blind Griffiths' algorithm, which uses the desired signal vector instead of a training sequence of symbols for initial adaptation. In this paper, a variable step-size (VSS) Griffiths' algorithm is proposed for accelerating the convergence speed, especially in the presence of strong interference. Numerical results show that the convergence properties of the VSS Griffiths' algorithm are robust against the wide eigenvalue-spread problem of the correlation matrix associated with the received signal vector compared to the Griffiths' algorithm using a fixed step-size.

Tail-biting trellises of linear and nonlinear block codes are addressed. We refine the information-theoretic approach of a previous work on conventional trellis representation, and show that the same ideas carry over to tail-biting trellises. We present lower bounds on the state and branch complexity profiles of these representations. These bounds are expressed in terms of mutual information between different portions of the code, and they introduce the notions of superstates and superbranches. For linear block codes, our bounds imply that the total number of superstates, and respectively superbranches, of a tail-biting trellis of the code cannot be smaller than the total number of states, and respectively branches, of the corresponding minimal conventional trellis, though the total number of states and branches of a tail-biting trellis is usually smaller than that of the conventional trellis. We also develop some improved lower bounds on the state complexity of a tail-biting trellis for two classes of codes: the first-order Reed-Muller codes and cyclic codes. We show that the superstates and superbranches determine the Viterbi decoding complexity of a tail-biting trellis. Thus, the computational complexity of the maximum-likelihood decoding of linear block codes on a tail-biting trellis, using the Viterbi algorithm, is not smaller than that of the conventional trellis of the code. However, tail-biting trellises are beneficial for suboptimal and iterative decoding techniques.

In this paper, we consider sufficient conditions for ruling out some useless iteration steps in a class of soft-decision iterative decoding algorithms for binary block codes used over the AWGN channel using BPSK signaling. Sufficient conditions for ruling out the next single decoding step, called ruling-out conditions and those for ruling out all the subsequent iteration steps, called early termination conditions, are formulated in a unified way without degradation of error performance. These conditions are shown to be a type of integer programming problems. Several techniques for reducing such an integer programming problem to a set of subprograms with smaller computational complexities are presented. As an example, an early termination condition for Chase-type decoding algorithm is presented. Simulation results for the (64, 42, 8) Reed-Muller code and (64, 45, 8) extended BCH code show that the early termination condition combined with a ruling-out condition proposed previously is considerably effective in reducing the number of test error patterns, especially as the total number of test error patterns concerned grows.

Optical Code Division Multiple Access (OCD- MA) has been emerging as an attractive scheme in fiber optic communication systems as well as in space communication systems in past few years. In OCDMA systems, M-ary Pulse Position Modulation (PPM), has been regarded as an efficient signalling format which has the capability to reduce the channel interference caused by the other users and also to increase the number of simultaneous users. We apply error control coding to improve the system performance of pulse position modulated OCDMA (PPM/OCDMA) systems and this paper investigates the performance of M-ary PPM/OCDMA systems with M-ary convolutional coding. Dual-k code is used as the M-ary convolutional code and Optical Orthogonal Codes with the maximum cross correlation value of 1 and 2 are employed as the signature sequences. We derive an expression for the bit error probability of the new system and show that combining M-ary convolutional coding and M-ary PPM results in an improved error performance. Also it is shown that the number of simultaneous users can be significantly increased with the proposed system compared to the uncoded PPM/OCDMA system with the same bit error probability and with the same information bit rate. We also analyze the system with binary convolutional coding and a comparison with the proposed system is given.

We prove that binary images of irreducible cyclic codes C over GF(2m) and binary concatenated codes of C and a binary [m+1,m,2] even-parity code are optimal (in the sense that they meet the Griesmer bound with equality) and proper, if a root of the check polynomial of C is primitive over GF(2m) or its extensions.

In this paper, we propose a preemptive priority handoff scheme for integrated voice/data cellular mobile systems. In our scheme, calls are divided into three different classes: handoff voice calls, originating voice calls, and data calls. In each cell of the system there is a queue only for data calls. Priority is given to handoff voice calls over the other two kinds of calls. That is, the right to preempt the service of data is given to a handoff voice call if on arrival it finds no idle channels. The interrupted data call returns to the queue. The system is modeled by a two-dimensional Markov chain. We apply the Successive Over-Relaxation (SOR) method to obtain the equilibrium state probabilities. Blocking and forced termination probabilities for voice calls are obtained. Moreover, average queue length and average transmission delay of data calls are evaluated. The results are compared with another handoff scheme for integrated voice/data cellular mobile systems where some numbers of channels are reserved for voice handoff calls. It is shown that, when the data traffic is not very light, the new scheme can provide lower blocking probability for originating voice calls, lower forced termination probability for ongoing voice calls, and shorter average queue length and less average transmission delay for data calls.

The growth behavior of copper particle on crystalline and amorphous silicon surfaces has been investigated. The study reveals that the growth behavior of copper particle depends on the substrate condition. When samples are intentionally contaminated in ultrapure water, both crystalline and amorphous silicon surfaces show no difference in their contamination levels. However, copper particles were not observed on an amorphous silicon surface except dipping in dilute CuCl2 solution. The copper concentration on an amorphous silicon surface after dipping in a 0.5% HF solution is similar to the level after contaminating in ultrapure water. The copper contamination level on a crystalline silicon surface, except from CuCl2 solution, decreased two orders of magnitude as compared with ultrapure water. The copper impurity level on crystalline silicon surface was reduced by two orders by cleaning in a sulfuric acid-hydrogen peroxide mixture. The sulfuric acid-hydrogen peroxide mixture cleaning was not effective on an amorphous silicon surface. When native oxide pre-existed on an amorphous silicon surface before contamination, however, the sulfuric acid-hydrogen peroxide mixture cleaning was effective for removing copper impurity. Our results suggest that copper contamination on an amorphous silicon surface have the characteristics of bonding directly with silicon and/or existing in the native oxide, in contrast with the situation on crystalline silicon surface. After contamination with 1000 ppm copper in CuF2 solution, the etch rate of an amorphous silicon film in a 0.5% HF solution was approximately one order of magnitude faster than that of crystalline silicon. This is attributed to the difference in crystalline structure between crystalline silicon and amorphous silicon.

This paper shows the method of theoretical analysis for the bit error probability of the trellis-coded partial response continuous phase modulation (TCM-PR-CPM) over the correlated Rician fast frequency nonselective fading channel. In the analysis, the fading correlation of the channel and the effect due to finite interleaver are taken into account. By applying the method to the rate 1/2 (7, 2) trellis code with the raised cosine pulse of length 2 (2RC) partial response signaling, we show that the tighter upper bounds of the bit error rate are obtained than those in the preceding report.

Synchronization and continuity are essential for multimedia presentation, but because network resources and available bandwidth are both limited, synchronization quality and continuity quality have to be traded off in response to the fluctuating network conditions. This paper therefore introduces an algorithm for intramedia synchronization with adaptive quality of service (QoS) control handled at different layers of multimedia streams. The work described here is an extension of our earlier proposal of a synchronization algorithm by delay compensation protocol with two resynchronization mechanisms: retrieval offset adjustment and data unit skipping. That algorithm has been extended by the introduction of QoS control mechanisms in the QoS plane of a distributed control platform. The extended approach results not only in better synchronization and continuity, but also integrates the QoS adjustment into the existing architecture. Unexpected QoS variations are coped with by an adaptive QoS control designed to maintain the desired application qualities within the fluctuating environment. Simulations implemented on a UDP/IP network have verified the effectiveness of the proposed scheme.

In this paper, we focus on regularity and set-valued functions. Regularity was first introduced by S. C. Kleene in the propositional operations of his ternary logic. Then, M. Mukaidono investigated some properties of ternary functions, which can be represented by regular operations. He called such ternary functions "regular ternary logic functions". Regular ternary logic functions are useful for representing and analyzing ambiguities such as transient states or initial states in binary logic circuits that Boolean functions cannot cope with. Furthermore, they are also applied to studies of fail-safe systems for binary logic circuits. In this paper, we will discuss an extension of regular ternary logic functions into r-valued set-valued functions, which are defined as mappings on a set of nonempty subsets of the r-valued set {0, 1, . . . , r-1}. First, the paper will show a method by which operations on the r-valued set {0, 1, . . . , r-1} can be expanded into operations on the set of nonempty subsets of {0, 1, . . . , r-1}. These operations will be called regular since this method is identical with the way that Kleene expanded operations of binary logic into his ternary logic. Finally, explicit expressions of set-valued functions monotonic in subset will be presented.

We proposed a soft-decision decoding algorithm for cyclic codes based on energy minimization principle. This letter presents the algorithm which improves decoding performance and decoding complexity of the previous method by giving more initial positions and introducing a new criterion for terminating the decoding procedure. Computer simulation results show that both the decoded block error rate and the decoding complexity decrease by this method more than by the previous method.

For the realization of low-voltage full-color FEDs, requirements for phosphor for the FED are proposed. Especially, the influence of released gases or substances from phosphors on the field emission within the FED was made clear. It was clarified that the analysis of F-N plots of the V-I curve of field emission characteristics was helpful to know the interaction of field emission and phosphors. In the experiment, we first obtained the depth from the phosphor surface of the low voltage electron excitation in case of ZnGa2O4, where the region available for cathodoluminescence at the anode voltage of 400 V is about 63 nm deep from the surface. The characteristic of the 12.4 cm-320(trio)240 pixels low-voltage full-color FED is reported. The luminance of 154 cd/m2 was attained at the anode voltage of 400 V and the duty factor of 1/241. Supported by the high potential of the FED as a flat panel, each problem shall be steadily solved to secure the firm stand as a new full color flat display in new applications.

We proposed a new method to evaluate display legibility as a function of resolution. This method was able to evaluated display legibility without being restricted to the display resolution. Using this method, subjective psychological experiments were carried out to investigate display resolution, which provides legibility, in observing small characters. Samples viewed by subjects were images displayed on a high-resolution TFT-LCD that we developed, CRT images and printed documents for comparison. We have found that TFT-LCD legibility was much better than that of CRT, and that minimum resolution of about 175 dpi was needed for use in legible document viewers.

This paper describes numerical analyses of resistive mixer operation, followed by measured performances of a V-band (50 - 75 GHz) monolithic InP HEMT resistive mixer operable with a very low LO power. Our model assumes that the channel conductance of the InP HEMT can be described by three linear functions according to the applied gate voltage. The calculated results obtained with the model have shown that the LO power level required for mixer operation is determined by the gate bias voltage and that a device with abrupt conductance shifts is suited to low LO power operation for a resistive mixer. It is also shown that conversion loss saturation of a resistive mixer is caused by its channel conductance saturation. A V-band monolithic resistive mixer has been designed and fabricated using Coplanar Waveguides (CPW) and a 0.15 mm InP HEMT with abrupt channel shifts. Good agreement between measured and simulated conversion losses are obtained. A minimum conversion loss of 8.4 dB is achieved at the 55 GHz RF-frequency and the -2 dBm LO power. It also exhibits an excellent IF output linearity to allow the 1 dB compression RF input level to be comparable with LO power, indicating good intermodulation performance. It is demonstrated that the proposed simple model of the channel conductance can easily calculate conversion characteristics of a resistive mixer with high accuracy.

We have realized excellent viewing angle characteristics for the π cell, by combining a discotic negative birefringence film, which has a hybrid alignment structure, and a positive a-plate. The negative birefringence of the film completely compensates the positive birefringence of the π cell liquid crystals in the dark-state. The roll of a c-plate, which should be accompanied by the a-plate to suppress the light leakage from crossed polarizer at oblique incident angles, was substituted for the vertically aligned component of the π cell liquid crystal. Taking into account the fast electrooptical response, which is one order faster than that of the twisted-nematic liquid-crystal display, the π cell is one of the most promising liquid-crystal-display modes.

In this paper, we describe an experimental evaluation of visual fatigue in a binocular disparity type 3-D display system. To evaluate this fatigue, we use a subjective assessment method and focus on mismatching between convergence and accommodation, which is a major weakness of binocular disparity 3-D displays. For this subjective assessment, we use a newly-developed binocular disparity 3-D display system with a compensation function for accommodation. Because this equipment only allowed us to compare the terms of the mismatching itself, the evaluation is more accurate than similar previous works.

Experiment is reported of enhanced backscattering of light in binary and ternary suspensions of rutile and/or alumina particles. With a conventional CCD camera system for observing the phenomena, the angular line shape and the enhancement factor were agreed with the theoretically predicted curve and value. Observation of the angular distribution scattered at the backscattered direction supported the hypothesis proposed by Pine et al. , in which the transport mean free path of the polydisperse mixture can be expressed in terms of summing its reciprocal values weighted over the particle sizes.