This letter proposes the method using a filter to suppress the very large noise obstructive to the radio pulsar surveys. This noise suppression filter is constructed from the average of the amplitude spectrum of pulsar signal for each channel. Using this method, the dispersion measure, one of the important parameters in the pulsar surveys, can easily be extracted.

We describe the characteristics of scattering and diffraction of plane E-waves by a lossy dielectric elliptic cylinder. The computational programs for calculating the analytic solutions for the diffraction of a lossy dielectric elliptic cylinder can be achieved. From the calculated results of the backscattering cross section (BSCS) (usually the radar cross section: RCS) and the forward-scattering cross section (FSCS) due to the cross-sectional shape and complex dielectric constant of the elliptic cylinder, the features of the BSCS and FSCS can be clarified as follows. (1) There is a cross-sectional shape of the cylinder which results in a minimum BSCS with a complex dielectric constant of the cylinder. (2) The BSCS and FSCS of the lossy dielectric scatterer approach zero as the scatterer approaches a strip. This result means that no material composing such a strip exists, and the features are very different from those in a perfectly conducting strip. (3) The influence of conductivity, σ, of the cylinder on a scattered wave is small for the relative dielectric constant of εr6. (4) The total scattering cross section of the lossy dielectric elliptic cylinder which causes the minimum BSCS is not small. Hence, it may be considered that the minimum BSCS is determined mainly by interference based on the cross-sectional shape and complex dielectric constant of cylinder, and is not caused by incident wave absorption due to the lossy dielectric.

A simple numerical method for calculating paths of creeping rays around an arbitrary convex object is presented. The adventage of this method is that the path of creeping ray is iteratively determined from initial values of incident point and incident direction of the creeping ray without solving differential equation of geodesic path. As the numerical examples, the path of creeping ray on the prolate spheroid and the resonance path of natural modes are shown.

For medical imaging, non-rigid motion analysis of the heart deformability is a nontrivial problem. This paper introduces a new method to analyze the gated SPECT (Single Photon Emission Computed Tomography) imges for 3-D motion information of left ventricular. Our motion estimation method is based on a new concept called normal direction constraint" in that the normal of a surface patch of some deforming objects at certain time instant is constant. This paper consists of the following processes: contour extraction, slices interpolation, normal vector field generation, expanding process, motion estimation for producing a 2-D motion vector field, and deprojection for a 3-D motion vector field. In the experiments, we will demonstrate the accuracy of our method in analyzing the 3-D motion field of deforming object.

In general, message passing multiprocessors suffer from communication overhead and shared memory multiprocessors suffer from memory contention. Also, data I/O overhead limits performance. In particular, computer vision tasks that require massive computation are strongly affected by these disadvantages. This paper proposes new parallel architectures for computer vision, a Flexibly (Tightly/Loosely) Coupled Multiprocessor (FCM) and a Flexibly Coupled Hypercube Multiprocessor (FCHM) to alleviate these problems. FCM and FCHM have a variable address space memory in which a set of neighboring memory modules can be merged into a shared memory by a dynamically partitionable topology. FCM and FCHM are based on two different topologies: reconfigurable bus and hypercube. The proposed architectures are quantitatively analyzed using computational models and parallel vision algorithms are simulated on FCM and FCHM using the Intel's Personal SuperComputer (iPSC), a hypercube multiprocessor, showing significant performance improvements over that of iPSC.

This paper describes a procedural detailed compaction method for the symbolic layout design of CMOS leaf cells and its algorithmic aspects. Simple symbolic representations that are loosely designed by users in advance are automatically converted into densely compacted physical patterns in two phases: symbolic–to–pattern conversion and segment–based detailed compaction. Both phases are executed using user-defined procedures and a specified set of design rules. The detailed compaction utilizes a segment–based constraint graph generated by an extended plane sweep method where various kinds of design rules can be applied. Since various kinds of basic operations can be applied to the individual segments of patterns in the procedures, the detailed procedure for processing can be described in accordance with fabrication process technologies and the corresponding sets of design rules. This combined stepwise procedure provides a highly flexible framework for the symbolic layout of CMOS leaf cells. The proposed approach was implemented in a symbolic layout system called CAMEL. To date, more than 300 kinds of symbolic representations of CMOS leaf cells have been designed and are stored in the database. Using several different sets of design rules, symbolic representations have been automatically converted into compacted patterns without design rule violations. The areas of those generated patterns were averaged at 98% of the manually designed patterns. Even in the worst case, the increases in area were less than about 10% of the manually designed ones. Furthermore, since processing times are much shorter than manual design periods, for example, 300 kinds of symbolic representations can be converted to corresponding physical patterns in only a day. It is evident, through these practical design experiences with CAMEL, that our approach is more flexible and process–tolerant than conventional ones.

A new algorithm, which is incorporated into the waveform relaxation analysis, for efficiently simulating the transient response of single lossy transmission lines or lossy coupled multiconductor transmission lines, terminated with arbitrary networks will be presented. This method exploits the inherent delay present in a transmission line for achieving simulation efficiency equivalent to obtaining converged waveforms with a single iteration by the conventional iterative waveform relaxation approach. To this end we propose 'line delay window partitioning' algorithm in which the simulation interval is divided into sequential windows of duration equal to the transmission line delay. This window scheme enables the computation of the reflected voltage waveforms accurately, ahead of simulation, in each window. It should be noted that the present window partitioning scheme is different from the existing window techniques which are aimed at exploiting the non–uniform convergence in different windows. In contrast, the present window technique is equivalent to achieving uniform convergence in all the windows with a single iteration. In addition our method eliminates the need to simulate the transmission line delay by the application of Branin's classical method of characteristics. Further, we describe a simple and efficient method to compute the attenuated waveforms using a particular form of lumped element model of attenuation function. Simulation examples of both single and coupled lines terminated with linear and nonlinear elements will be presented. Comparison indicates that the present method is several times faster than the previous waveform relaxation method and its accuracy is verified by the circuit simulator PSpice.

On ranging system on short distance using spread spectrum, we examine waveform responses to predict the state of electromagnetic waveform propagation while the signal is received after scattered by a target. Then this system and the numerical results are discussed.

An optimal control theory has been applied to a biological compartment system to show a method to analyze the control principle of biological system represented by compartments. Present theory has been proposed to afford a theoretical back ground and validity for the strategy of drug administration or control of the anesthetic agent in practical medicine. The instantaneous change of the concentration of a given material within a biological system has been expressed by differential equations. Each compartment has been set to be transferred a material from all other compartments and conversely each compartment sends it to all other compartments. The control input was restricted to be one kind. The performance function involved the deviation from the target value, the rate of change in concentration and the amount of the control variables. The biological system was defined to operate optimally only when the performance function has been minimized during a given time period. By the optimal control theory of Pontoriagin, above biological problem has been converted to a mathematical problem and was solved numerically by multiple shooting method. The calculated trajectory of the optimal control has been asymmetric parabolic one with the maximum at its initiation and the minimum at the middle of total reaction time. This pattern has been consistent with that of probable transient change of the concentration of anesthetic agent when it has been inhalated under the most up to date "Rapid Inhalation Induction" method. The optimal trasient change of the concentration at each compartment has beeb affected by the difference in time dependent nature and the magnitude of the transfer rate. Present theory afforded a method to analyze the control strategy of biological system expressed by compartments model and showed an availability for actual clinical medicine. The optimal control principle must be a most adequate one to describe the Homeostasis in biological system.

In this letter we present an electronic circuit based on a neural net to compute the discrete Walsh transform. We show both analytically and by simulation that the circuit is guaranteed to settle into the correct values.

Fractal image coding using iterated transformations compresses image data by exploiting the self–similarity of an image. Its compression performance has already been discussed in [2] and several other papers. However the relation between the performance and the self–similarity remains unclear. In this paper, we evaluate fractal coding from the perspective of this relationship.

Some qualitative properties of an inductively coupled circuit containing two Josephson junction elements with a dc source are investigated. The system is described by a four–dimensional autonomous differential equation. However, the phase space can be regarded as S1×R3 because the system has a periodicity for the invariant transformation. In this paper, we study the properties of periodic solutions winding around S1 as a bifurcation problem. Firstly, we analyze equilibria in this system. The bifurcation diagram of equilibria and its topological classification are given. Secondly, the bifurcation diagram of the periodic solutions winding around S1 are calculated by using a suitable Poincar mapping, and some properties of periodic solutions are discussed. From these analyses, we clarify that a periodic solution so–called "caterpillar solution" is observed when the two Josephson junction circuits are weakly coupled.

In this letter we propose an interpolation technique for low-quality fingerprint images for highly reliable feature extraction. To improve the feature extraction rate, we extract fingerprint features by referring to both the interpolated image obtained by using a directional Laplacian filter and the high-contrast image obtained by using histogram equalization. Experimental results show the applicability of our method.

This paper proposes a new class of unidirectional byte error locating codes, called single symmetric bit error correcting and single unidirectional byte error locating codes, or SEC–SUbEL codes. Here, "byte" denotes a cluster of b bits, where b2. First, the necessary and sufficient conditions of the codes are clarified, and then code construction method is demonstrated. The lower bound on check bit length of the SEC–SUbEL codes is derived. Based on this, the proposed codes are shown to be very efficient in some range of the information length. The code design concept presented for the SEC–SUbEL codes induces the generalized unidirectional byte error locating codes with single symmetric bit error correction capability.

A coupled-mode analysis of a symmetric planar nonlinear directional coupler (NLDC) is presented by using a singular perturbation scheme. The effects of linear coupling and nonlinear modification of refractive index are treated to be small perturbations, and the modal fields of isolated linear waveguides are employed as the basis of propagation model. The self-consistent first-order coupled-mode equations governing the transfer of optical power along the NLDC are obtained in analytically closed form. It is shown that tha critical power for optical switching derived from the coupled-mode equations is in close agreement with that obtained by the numerical analysis using the finite difference beam propagation mathod.

This paper presents a cost-effective network for very large ATM cross-connects. In order to develop it, we propose the delta network with expanded middle stages. This proposed network is the intermediate network between a nonblocking network and the delta network with respect to the cost of hardware and internal blocking probability. Using this network, we explore the tradeoff between the cost and internal blocking probability, and derive the optimum configuration under temporarily deviating traffic. Internal blocking occurs when input traffic temporarily deviates from its average value. However, we cannot evaluate the internal blocking probability by using conventional traffic models. In this paper, we adopt temporarily deviating traffic such that all traffic is described as the superposition of the paths which are defined by traffic parameters. As can easily be seen, the path corresponds to virtual path (VP) or virtual channel (VC). Therefore, we believe that our model describes actual traffic more exactly than conventional models do. We show that the optimum configuration is the proposed network whose expansion ratio γ=3 when the maximum number of paths that can be accommodated in one link is greater than 22. This network achieves the internal blocking probability of 10-10. As an example of this network, we show that the proposed network of size 7272 is constructed with only 40% of the hardware required by the nonblocking network.

Measuring mechanical characteristics of optical disks is significant not only for designing drives but also for assuring disk interchangeability. This paper shows that the lens-movement detection method has the greatest overall potential and thus fits to a practical system for measuring mechanical characteristics. A system based on this method was constructed by developing simple and accurate capacitive sensors that can be built into an optical head to detect lens movement. The system configuration includes a precision turntable and a high-duarability reference disk to fully extract the potential. Test results show that this measuring system has adequate measuring range, accuracy, and stability. Some applications of this system are described in this paper. They show that the system is useful for evaluating and improving optical disk mechanical characteristics.

The electric or electronic circuits have many contact devices such as relay and switch. The contact between two nominally conducting flat surface has a lot of micro contact spots. The constriction resistance of the contact is known to determine the sum of the parallel resistance of the micro contacts and the interaction of them. The constriction resistance of two circular conducting spots was approximately formulated by Greenwood. This formulation shows that the interacted resistance of two circular spots is in inverse proportion to the distance between two conducting spots. It was known that this effect is introduced by the interaction between two conducting spots. However, the condition of interaction in the spots is not clear. Calculating the current density distribution in the spots is important to clarify the condition of interaction. The numerical analysis is very suitable to calculate the current density in the spots. In the fundamental case of the computation of the current density the boundary element method (BEM) is more efficient and accurate than that of the finite element method (FEM) because the boundary condition at the infinite is naturally satisfied and is not required a great number of the element in a wide space. In this paper the current density in the square spots is computed by the BEM. As the distance between two conducting spots becomes small, the current density in the two spots decreases. It becomes clear that the constriction resistance of conducting spots is increased by this effect. The decrease of current density by interaction is not uniformly, that at the near location to the opposite spot is larger than that at the far location in the same spot. In this paper the constriction resistance of two conducting spots is also considered. It was known that the constriction resistance of one conducting spot is not influenced by the form of spot very much. However, that of two conducting spots is not clear. The constriction resistance of two square spots is also computed by the BEM. The computed values of the constriction resistance of two square spots are compared with that of two circular spots by Greenwood's formulation and other results. As the result, it is clear that they have the considerable discrepancy. However, the trend of the variations is almost agree each other.

A new method for the accurate extraction of glottal source parameters is proposed. This method, called Heuristic Analysis-by-Synthesis (HAbS), has been developed specifically to overcome the weaknesses of other methods of glottal source parameter extraction. The specific features of this method are the use of the AbS method for extraction of glottal source and vocal tract parameters, the use of a parametric glottal source model during vocal tract analysis, the use of alternating glottal source and vocal tract analyses, and simultaneous, time-domain analysis of the glottal source parameters and the first formant. This method has been implemented in such a way that user interaction is not required. The performance of the HAbS method is evaluated using both synthetic-speech and natural-speech data. Error is measured in both the time domain and the spectral domain, and the standard deviation of extracted parameter values is computed. In addition, the error in analysis of each glottal-source parameter is computed using synthetic-speech data. In order to assess the accuracy of the HAbS method as compared to other methods, three other methods (LPC, AIF, and AbS) are evaluated using the same data methods of error measurement. From these evaluations, it is clear that the HAbS method yields results that are more accurate than these other methods.

Single-crystal LiNbO3 and LiTaO3 piezo-electric resonators were developed for surface-mount technology (SMT) used in electronic equipment manufacturing. Using an energy-trapping design, a shear-mode piezoelectric resonator chip is bonded directly to the board with conductive resin and covered with a ceramic cap. The process occasionally produces nonlinear resonators, however, which led us to study the frequency characteristics of impedances for the abnormal samples. Their input impedances at the resonant frequency depended on the driving voltage. The insulator between the thin film metal electrode on the crystal strip or the thick film electrode on the ceramic base, in conjunction with silver balls in the adhesive resin, apparently caused the problem. Assuming that the insulator makes diode contacts, which show stable nonohmic phenonena or cause a discharge in a conductor causing a drastically changing in the impedance, we proposed the following corrective action：subject the nonohmic contacts to a high-voltage frequency-swept signal near the resonant frequency. The samples subjected to the high voltages recovered metalic contact and maintained even after severe thermal cycle testing.