Subcarrier multiplexing (SCM) transmission over optical fiber for microcelluler mobile communication systems has been actively studied. However, as increasing the number of channels, intermodulation distortion (IMD) becomes the intrinsic problem. On the other hand, coherence multiplexed (CM) system for broad-band access communications has been developed and may find wide spread application because of its simplicity and flexibility. However the interference noise produced by the mixing of different optical channels at a photodetector is the serious problem. Therefore, on the down link for fiber optic microcell systems, it is attractive to consider the combination of SCM and CM: coherence multiplexed/subcarrier multiplexing (CM/SCM). In this hybrid scheme, since each optical channel is modulated by M microwave subcarriers, the bandwidth allocation is very flexible. In addition, the same microwave subcarrier frequency may be used among the different optical channels, because the optical channels are uncorrelated each other. We derive the received carrier-to-noise ratio (ONR) characteristics of CM/SCM system with optical amplifier as preamplifier or in-line amplifier for the optical down link from central station to base stations. The system performance of CM/SCM system is compared with those of coherent SCM (C-SCM) and CM systems from the viewpoint of the maximum number of base stations to be admitted. It is shown that the performance of CM/SCN system is superior to those of C-SCM and CM systems when optical power at the input to in-line amplifier is limited. CM system has good performance when preamplifier gain and optical power are large, and C-SCM system is the best when in-line amplifier is used.

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.

In the traditional note symbol extraction processes, extracted candidates of note elements were identified using complex if-then rules based on the note formation rules and they needed subtle adjustment of parameters through many experiments. The purpose of our system is to avoid the tedious tasks and to present an accurate and high-speed extraction of note heads, stems and flags according to the following procedure. (1) We extract head and flag candidates based on the stem positions. (2) To identify heads and flags from the candidates, we use a couple of three-layer neural networks. To make the networks learn, we give the position informations and reliability factors of candidates to the input units. (3) With the weights learned by the net, the head and flag candidates are recognized. As an experimental result, we obtained a high extraction rate of more than 99% for thirteen printed piano scores on A4 sheet which have various difficulties. Using a workstation (SPARC Station 10), it took about 90 seconds to do on the average. It means that our system can analyze piano scores 5 times or more as fast as the manual work. Therefore, our system can execute the task without the traditional tedious works, and can recognize them quickly and accurately.

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.

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.

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.

The E-polarized plane wave diffraction by a perfectly conducting strip located at the plane interface between two different media is analyzed by the Wiener-Hopf technique. Applying the boundary conditions to the integral representations for the unknown scattered field, the problem is formulated in terms of the modified Wiener-Hopf equation(MWHE), which is reduced to a pair of simultaneous integral equations via the factorization and decomposition procedure. The integral equations are solved asymptotically for large strip width via the method of successive approximations leading to the first, second and third order solutions, which are valid at high frequencies. The scattered far field expression is derived by taking the inverse Fourier transform and applying the saddle point method. It is shown that the high-frequency scattered far field comprises the geometrical optics field, the singly, doubly and triply diffracted fields and the lateral waves. Numerical examples of the radar cross section(RCS) and the lateral waves are presented, and the far field scattering characteristics discussed in detail.

Through comparing the results of two successive IPTP Character Recognition Competitions which focused on 3-digit handprinted postal codes, we herein analyze the methodologies of the submitted algorithms along with the substituted or rejected patterns of these algorithms. Regarding their methodologies, lesser diversity was apparent specifically concerning the contour-chain code based on local stroke directions and statistical discriminant functions for feature extraction and discrimination. Analysis of the patterns demonstrated that the misrecognized patterns being most often improved were categorized as a decrease in peculiarly shaped handwritten characters or heavy-handed and disconnected strokes. However, most of the remaining misrecognitions were still classed as peculiarly shaped handwriting as commonly shared between the best three algorithms. From these analyses, we could delineate a direction to be taken for developing more effective methodologies and clarify the remaining problems to be overcome by the subsequent intensive research. Furthermore, we evaluate in this article our multi-expert recognition system for achieving higher recognition performances by means of combining complementary recognition algorithms. We performed a subsequent investigation of the Candidate Appearance Likelihood Method using novel experimental conditions and a new examination of the application of the neural network as the combining method for accumulating the broader candidate appearances. The results obtained confirm that combining through the neural network constitutes one of the most effective ways of making the multi-expert recognition system a reality.

This paper is described on the realization of simulated inductance cercuit with parallel negative conductance and its application for an oscillator. The design's condition for realizing the circuit needs stability, narrow expance of elements, larger dynamic-range and lower sensitivity. A new floating simulated inductance circuit with parallel nagative conductance with two operational amplifiers, four resistors, and four capacitors is created by using the design's algorithm. And the elements sensitivity of the simulated circuit is superior to that of the conventional circuits. By experimenting with a resonance circuit, the author tested the sinusoidal oscillator's circuit of a parallel -GLC as an application in order to confirm the operation of the simulated inductance circuit with parallel negative conductance.

A clique of a graph G(V,E) is a subset of V such that every pair of vertices is connected by an edge in E. Finding a maximum clique of an arbitrary graph is a well-known NP-complete problem. Recently, several polynomial time energy-descent optimization algorithms have been proposed for approximating the maximum clique problem, where they seek a solution by minimizing the energy function representing the constraints and the goal function. In this paper, we propose the binary neural network as an efficient synchronous energy-descent optimization algorithm. Through two types of random graphs, we compare the performance of four promising energy-descent optimization algorithms. The simulation results show that RaCLIQUE, the modified Boltzmann machine algorithm, is the best asynchronous algorithm for random graphs, while the binary neural network is the best one for k random cliques graphs.

Induced noises from breaking contact arc discharge and sliding contact discharge of dc motor are measured by pick up coil and current probe. Statistical properties, amplitude distribution probability (APD), of induced noise waveform are analyzed by simple method using intermediate frequency of spectrum analyzer. It is shown that APD characteristics can be used to estimate statistical characteristics and peak value of induced noise. Simulation model of the noise made by the combination of Gaussian noise is mentioned. The model called the composite noise generator (CNG) can be good fit to the real characteristics of both noises from breaking arc and dc motor. Applications of the CNG for noise filter using toroidal coil shows that the CNG is useful to realize the test of noise suppression characteristics. What parameters of the CNG should be considered is described for further applications.

GaAs 10 Gb/s 64:1 Multiplexer/Demultiplexer chip sets have been successfully developed. The 64-bit 156 Mb/s parallel data output or input of these chip sets can be directly connected to CMOS LSIs. These chip sets consist of a 10Gb/s 4: 1 MUX IC, a 10 Gb/s 1: 4 DEMUX IC, four 2.5 Gb/s 16: 1 MUX LSIs and four 2.5 Gb/s 1: 16 DEMUX LSIs. This multi-chip construction is adopted for low power dissipation and high yield. The basic circuit employed in the 10 Gb/s4: 1 MUX/DEMUX ICs is an SCFL circuit using 0.4 µm-gate FETs with a power supply of -5.2 V, and that in 2.5 Gb/s 16: 1 MUX/DEMUX LSIs is a DCFL circuit using 0.6 µm-gate FETs with a power supply of -2.0 V. These chip sets have functions for synchronization among these ICs and to enable bit shift to make the system design easier. In the 10 Gb/s 4: 1 MUX IC, a timing adjuster is adopted. This timing adjuster can delay the timing of the most critical path by 50 ps. Even if the delay times are out of order due to fluctuations in process, temperature, power supply voltage and other factors, this timing can be revised and the 4: 1 MUX IC can operate at 10 Gb/s. Furthermore, a 48-pin quad flat package for 10 Gb/s 4: 1 MUX/DEMUX ICs has been newly developed. The measured insertion loss is 1.7 dB (at 10 GHz), and the isolation is less than -20 dB (at 10 GHz). These values are sufficient in practical usage. Measurements of these chip sets show desirable performance at the target 10 Gb/s. The power dissipations of the 64: 1 MUX/DEMUX chip sets are 10.3 W and 8.2 W, respectively. These chip sets is expected to contribute to high speed telecommunication systems.

Protective layers in AC plasma display panels (PDP) are usually formed by vacuum vapor deposition or sputtering. It is important to study the protective MgO layer by means of screen-printing for fabricating a large size PDP and reducing its cost. With the objectives of enlarging the panel size and reducing cost, we studied the fabrication of the protective MgO layer by means of screen-printing. In this study, we succeeded in lowering the drive voltage by using a MgO powder prepared by vapor phase oxidation instead of conventional decomposition of the magnesium salt. Further, by adding a MgO liquid binder, we attained a good luminous efficiency twice as high as that attained with a sputtered protective layer and lowered the drive voltage. When this protective layer was combined with He-Xe gas enclosure, the half-life of luminance was 5,000 hours. With Ne-Xe gas, the luminance deteriorated no more than 40% after 5,000 hours. A screen-printed protective MgO layer containing no MgO liquid binder showed a short half-life of 800 hours even with the use of Ne-Xe gas. In this case, the discharge voltage changed greatly and some cells did not discharge. It is concluded that the combination of an ultrafine MgO powder prepared by vapor phase oxidation and a MgO liquid binder can clear the way for making AC PDPs with a long lifetime, high efficiency, and low voltage a practical reality.

The local moment functions for discrete Wigner trispectrum are examined in ambiguity and in time-frequency domain. A concept of multiple and multidimensional circular convolution in frequency domain is introduced into the discrete Wigner higher order time-frequency signal representation of any order. It is shown that this concept based on the 1st order spectra of the signal offers an insight into the properties of inconsistent local moment functions and their representation both in ambiguity and time-frequency domain. It allows to prove that midfrequency crossterms of a multicomponent signal can not be removed by any generalized 4th order ambiguity function which employ kernel function in the ambiguity domain. It is shown, that the concept of multiple convolution in frequency domain can lead to the crossterm-reduced discete time-frequency representations of any order

Arc discharge at switching contacts is one of the key phenomena, because it strongly affects material wear/transfer, contact resistance and electromagnetic interference (EMI). The arc discharge is classified into various types from the viewpoint of its sustaining mechanism and voltage waveform. They are mainly steady arc, showering arc and initial arc. Furthermore, a steady arc consists of two stages named metallic phase arc and gaseous phase arc. In the metallic, phase arc, metal ious from the electrodes mainly sustain the arc. On the other hand, gas ions from the surrounding atmosphere play an important role in the gaseous phase. Each phase arc has different influence on contact performance and EMI. The purpose of this paper is to review the arc discharges at light duty electrical contacts, and to survey the effects of arc discharges on material transfer and EMI.

Digital halftoning is a well-known technique in image processing to convert an image having several bits for brightness levels into a binary image consisting only of black and white dots. A great number of algorithms have been presented for this problem, some of which have only been evaluated just by comparison with human eyes. In this paper we formulate the digital halftoning problem as a combinatiorial problem which allows an exact solution with graph-theoretic tools. For this, we consider a d-dimensional grid of n := Nd pixels (d 1). For each pixel, we define a so-called k-neighborhood, k {0,...N - 1}, which is the set of at most (2k + 1)d pixels that can be reached from the current pixel in a distance of k. Now, in order to solve the digital halftoning problem, we are going to minimize the sum of distances of all k-neighborhoods between the original picture and the halftoned one. We show that the problem can be solved in linear time in the one-dimensional case while it looks hopeless to have a polynomial-time algorithm in higher dimension including the usual two-dimensional case. We present an exact algorithm for the one-dimensional case which runs in O(n) time if k is regarded to be a constant. For two-dimensional case we present fast approximation techniques based on space filling curves. An experimental comparison of several implementations of approximate algorithms proves that our algorithms are of practical interest.

The charge neutralized at a small gap discharge has been evaluated from measured electromagnetic fields by two methods. The small gap discharges simulate ESD events. The evaluated charge decreases rapidly as a step shape immediately in a moment of the discharge. The accumulated static charge and the risetime of the neutralization step increase with the gap length. When the gap length is 0.1mm, risetime and the initial static charge are about 0.3ns and 5.6nC, respectively.

A high speed and low power consumption SCFL circuit design with low supply voltage is proposed. Focusing on the relationship between logic swing and supply voltage, the lower limit for the supply voltage is presented. Theoretical analysis and circuit simulation indicates that the logic swing needs to be optimized to maintain high average gm within the swing. An SCFL D-FF fabricated using a 0.25 µm n-AlGaAs/i-InGaAs HJFET process operates at up to 10 Gbps with power consumption as low as 19 mW at a supply voltage of 1.3 V.

A new superresolution technique is proposed for high-resolution estimation of the scattering analysis. For complicated multipath propagation environment, it is not enough to estimate only the delay-times of the signals. Some other information should be required to identify the signal path. The proposed method can estimate the frequency characteristic of each signal in addition to its delay-time. One method called modified (Root) MUSIC algorithm is known as a technique that can treat both of the parameters (frequency characteristic and delay-time). However, the method is based on some approximations in the signal decorrelation, that sometimes make problems. Therefore, further modification should be needed to apply the method to the complicated scattering analysis. In this paper, we propose to apply a time-domain null filtering scheme to reduce some of the dominant signal components. It can be shown by a simple experiment that the new technique can enhance estimation accuracy of the frequency characteristic in the Root-MUSIC algorithm.

Surface discharge is widely used for industrial ozonizers and toxic gas treatments, and is noise source. In this paper, an experimental investigation from the point of view of electromagnetic compatibility (EMC) has been conducted to evaluate the noise characteristics of surface discharge combustion flue gas cleaning systems. Mechanisms of propagation, coupling and formation are proposed based on the experimental observations.