bluuebunny/crossref_metadata_2025_split huggingface dataset:
A method of two‐dimensional filter image with a nonseparable autocovariance function
Authors: Mizuno Harunobu , Omatsu Shigeru , Soeda Takashi 
Published: July 2007

AbstractRecently, various methods have been reported for two‐dimensional image enhancement with the development of satellite image and medical image processing. This paper proposes a two‐dimensional filter for the image with a nonseparable autocovariance function in order to reduce the memory storage and processing time. Also, a simple method of estimating the necessary statistics to compose the filter is considered. The proposed two‐dimensional filter is a stable one which satisfies an estimation criterion of unbiasness and minimum variance. Also, the filter introduced here is completely equivalent to the Kalman filter algorithm when the filter parameters a1, a2, a3 are such that a3 = 0 and a1 or a2 = 0. Thus, the proposed filter is a natural extension of a classical Kalman filter into a two‐dimensional system. Finally, we compare existing methods with the proposed method by simulation, and examine qualitatively the contention that the estimation accuracy and computation time of the proposed method are superior to the others.
Synthesis of lattice digital filters by the state variable method
Authors: Takizawa Masao , Kishi Hisao , Hamada Nozomu 
Published: July 2007

AbstractOne method for realizing a rational transfer function as a lattice digital filter is the procedure of Gray et al. using tap coefficient devices. Use of these devices should be avoided from the viewpoint of minimizing the number of multipliers. We have derived a discrimination condition and divided the structures into two classes; those realizing the rational transfer functions with lattice structures only and those requiring tap coefficient structures. A method is proposed for constructing lattice digital filters based on the state‐variable procedure. This method is systematic and suited for computer‐based design. The analysis is also simple. In the case of a general nth order filter it is shown that the coefficient sensitivity is low and a zero‐input limit cycle never occurs in complement truncation.
Method of random image systhesis by means of computer
Authors: Yoshida Yasuo , Ogura Hisanao , Sakura Yasuo 
Published: July 2007

AbstractFor fundamental research on image filtering, spectral estimation, identification, coding etc., it is beneficial to use a digital computer to generate a random image satisfying a given statistical property. The present paper defines random image as a random field satisfying a stochastic difference equation. The image is linearly syhthesized from a white‐noise field, namely, a series of independent random numbers. In terms of the 2‐dimensional prediction theory a detailed method to determine the 2‐dimensional autoregressive representation for the random field is given. Next, a hybrid method is given which uses Fourier transform in one dimension and 1‐dimensional prediction theory in the other dimension. The method of Green function is given for a special application, and a method which uses 2‐dimensional Fourier transform is described briefly. A concrete calculation is given using the cross‐type partial difference equation for the random field with an isotropic spectrum. Comparison of these four methods shows that there is little difference in the number of multiplications in the processing. However, the first method aids in generation of a large image by a computer with small memory.
Multi‐source‐sink pairs connection in a network and its heuristic algorithm
Authors: Onaga Kenji , Arimoto Atsushi , Kishimoto Kazuo 
Published: July 2007

AbstractThe problem of providing the required numbers ri of paths between specified q pairs of sources si and sinks ti (i = 1, 2,…, q) in a graph with edges having capacities which limit the numbers of their usages is called the realization problem of multi‐source‐sink pair connection in a network. Since this is an NP‐hard problem there are no suitable heuristic algorithms to solve it; however, it has a wide range of applications. This paper presents a heuristic algorithm based on Onaga's necessary and sufficient condition (called supply‐consumption inequality). Its effectiveness is examined by measuring its speed and accuracy with computational experiments. The connection time per a connection was proportional to the number of nodes of a graph (≦ 132) and accuracy was more than 96%.
Microwave endless phase shifter using dual‐gate FET
Authors: Ichikawa Hirohumi , Komaki Shozo 
Published: July 2007

AbstractEndless phase shifters in which phase angles up to 360° can be endlessly varied are required in such areas as space diversity. Conventional endless phase shifters are large in size because they employ waveguides. To make these phase shifters in an MIC form, this paper adopts a method in which the input signal is divided into two with a 90° phase difference and then vector‐combined with appropriate amplitude ratios. To reduce the loss caused by an MIC, we use the dual‐gate GaAs MESFET as an active element. Realization of an FET endless phase shifter requires a dual‐gate FET amplitude adjustment circuit with a small amount of phase shift for a second gate bias. A method of optimizing the second gate terminating impedance to minimize the phase shift has been experimentally studied, although no theoretical analysis is available to date. In this paper, we analyze an equivalent circuit including the bias dependence of the circuit parameters of the FET and numerically compute the amplitude and phase of a dual‐gate FET. The results are compared with those of experiments. It is found that a theoretical design of the second gate terminating impedance is possible. Finally, the results for a fabricated FET endless phase shifter are described.
A general theory of the raman‐type free‐electron laser
Authors: Shiozawa Toshiyuki 
Published: July 2007

AbstractA theoretical consideration is given for the stimulated Raman scattering by a relativistic electron beam uniformly magnetized with finite magnitude in the direction of its motion, assuming an intense electromagnetic wave for the pumping source. With the aid of analytical and numerical approaches, special attention is paid to the behavior of the scattered wave in the vicinity of electron cyclotron resonance. The interesting results obtained by the cyclotron resonance are summarized as follows. First, according to the conditions imposed on the pump wave, the scattered wave becomes either the electromagnetic wave mode or the electron cyclotron wave mode, or it is not excited. In addition, in the presence of a finite static magnetic field, the spatial growth rate for the electromagnetic scattered wave takes a maximum value for a particular set of various parameters, and the maximum growth rate becomes one order of magnitude or more (about 20 times in the specific numerical examples illustrated) as large as the growth rate for the case with no static magnetic field applied.
Millimeter wave video detection using pb thin film microbridge josephson junction
Authors: Yoshimori Shigeru , Kawamura Mitsuo 
Published: July 2007

AbstractAn experiment in video signal detection at 70 GHz was conducted with a Pb micro‐bridge prepared by electron‐beam exposure and the lift‐off method. It was found that for the dc Josephson effect the external noise is dominant over the internal noise of the specimen and that the equivalent noise becomes large near the critical temperature. The response to 100 kHz amplitude‐modulated signals was found to be ten times more rapid than that of the superconductor bolometer. Theoretically the maximum responsivity is obtained near the first Shapiro step, which, however, does not give a stable bias; maximum responsivity was actually observed near the zeroth Shapiro step, where it exceeded 6.3 × 104 V/W. The responsivity was found to increase with increasing IcRn.
Circularity of the pitch of complex tones and its application
Authors: Member Kengo Ohgushi, Regular 
Published: July 2007

AbstractPaired comparison experiments were performed for the pitch of complex tones composing the endless scale as proposed by Shepard and those of two kinds of complex tones which are obtained by modifying the spectrum structure of the former complex tones. The results were analyzed by the multidimensional scaling program by Kruskal. As a result, it is shown that the pitch of the one, which is one of the three fundamental psychological attributes of the tone, has the mixed one‐ and two‐dimensional property in the case of the above complex tones. The tendency in the pitch comparison greatly differed by individuals, which can be accounted for by considering that the emphasis of the two elements of the pitch, which are tone height and tonality, differs by individuals. Using complex tones composing endless scale over 7 intervals, a melody over 10 intervals could be composed in a natural way.
Appearance of spatial sine‐wave pattern by exposure time
Authors: Member Haruo Sakata, Regular 
Published: July 2007

AbstractThe appearance of the temporal step pattern of the spatial sine‐wave (frequency 1.2 cpd) confirmed that the visual information pathways consist of two systems with different time response (they are assumed to be spatial and temporal dominant systems). In the foveal vision, the sensitivity shows a peak of about 50 ms exposure time. On the other hand, in the peripheral vision, the sensitivity reaches a peak of about 64 ms exposure time and shows a recess around 110 ms. These results at least indicate that there are two parallel pathways of difference temporal frequency bandwidths at the retinal periphery.
Bilevel rendition method for documents including gray‐scale and bilevel image
Authors: Tetsutani Nobuji , Ochi Hiroshi 
Published: July 2007

AbstractThe demand of facsimile transmission of printed matter as well as photographs is becoming strong daily as the variety of information is increasing. The disadvantage of the previous methods is that the character quality is deteriorated because in the case of artificial half‐tone reproduction using black and white recording, the resolution is sacrificed and tonal reproduction is performed. In this paper, a method to solve this problem is reported in which each block consisting of multiple picture elements is distinguished as bilevel region or gray‐scale region, and the processing suitable to each region is performed. This paper also describes the results of computer simulation obtained by applying this method to reproduce the characters and photographs. Moreover, the case of gray‐scale region lying inside the character region is discussed and it is shown that a simple region correction method is very effective.
Decrease in induced voltage on buried coaxial cable due to direct lightning stroke by earthing of metallic sheath
Authors: Member Toshiharu Nagano, Regular 
Published: July 2007

AbstractWhen a direct lightning stroke hits a cable in which the metallic sheath is insulated from ground a high voltage is induced between the metallic sheath and the cable core and this may result in multiple insulation breakdowns in the cable and associated equipment. Compared to the case in which the sheath is in direct contact with the ground, attenuation of the lightning current in the cable is relatively small and it has been found that this is the reason for the low attenuation of the distributed electromotive force in the circuit formed by the core and the metallic sheath. If the metallic sheath is grounded to cause a distributed flow of lightning current into the earth, attenuation of the sheath current can be greatly increased and it can be expected that the induced voltage will be lowered, reducing the failure rate. Using the inverse Laplace transformation, the sheath current and induced voltage are computed for the case where the coaxial cable is grounded at equal intervals in a repeater section. It is found that grounding at 450‐m intervals results in induced voltage between the inner and outer conductors of the coaxial pair which is about 60% of the voltage for grounding at 3600 m intervals and the failure rate is reduced to about one‐fourth. This method permits accurate determination of the crest value of the inflowing current which will not cause insulation breakdown failure in the cable and permits us to devise lightning countermeasures which will hold the failure occurrence rate to allowable limits.
Appearance of short‐exposure colorlight–two successive colors and single color
Authors: Member Haruo Sakata, Regular 
Published: July 2007

AbstractWhen comparing the three primary colors red, green and blue of equal luminance, the perceptual latency of blue is proved to be longer than that of red and green. Also, when two of the three primary colors are presented successively, the resultant color appears close to the second. This latter phenomenon suggests the presence of a temporal masking effect in the color mechanism. From these two phenomena, the fact that light from dark conditions of cyan and magenta presented for a short, rather than long, time appears close to blue because the perceptual latency of blue is longer compared to the other two. This is reasonably attributable to the color masking effect.
Analysis of probabilistic behavior of the system with nonregeneration points interpreted as Petri net by Markov renewal processes
Authors: Sugasawa Yoshio , Murata Koichi , Kurabayashi Yoshio 
Published: July 2007

AbstractA Petri net is a system in which a meaning of simple interpretation is assigned to a set of signals. Petri nets can provide a particularly effective means of modeling a parallel operation. One of the advantages to be derived by modeling a system with a Petri net is the establishment of relationships between certain net structures and dynamic behavior. We begin by introducing a simple semaphore system interpreted as a Petri net. At the occurrence of a transition, the system states can be classified into regeneration points and nonregeneration points. Limiting probabilities of the system behavior are derived by applying a Markov renewal process. Finally, the time‐ratio concept is introduced and system deadlock is studied by analyzing the realtion between the change‐of‐time ratio and the limiting probability.
Complex bases in active CR networks and their relations with the network excitation
Authors: Ozawa Takao , Itoh Hiroshi 
Published: July 2007

AbstractA complex basis can be defined for a set X of variables, such as branch currents and voltages (excluding the exciting currents and voltages), of a linear lumped‐constant network in the sinusoidal steady state. If a subset Xβ of X satisfies the condition that any variable in X – Xβ can be expressed as a linear combination of variables in Xβ with constant (not including the frequency) coefficients, then Xβ is called a complex basis of X. This paper derives general graph‐theoretical expressions for complex bases of the set of branch voltages and the set of modified branch voltages (= capacitor voltages x j, and/or resistor voltages) of an active CR network which satisfies certain conditions. The expressions derived have the same form as that in the case of a passive CR network. Second, the independence of the modified branch voltages which are obtained by varying both the phasor‐values (= effective values and phases) and the frequency of the excitation, is discussed. Let Xβ(k) be the vector of complex basis variables obtained by the kth excitation and let Xβ = [Xβ(1) ‐Xβ(k) ‐ Xβ(±) ] be the matrix obtained by A excitation. Then it is shown that there always exist some excitations which make Xβ regular. Finally, excitations which make Xβ regultvr can be actually specified, if the network satisfies certain conditions.Acknowledgements. This research was partly supported by the Grant‐in‐Aid for Scientific Research by the Ministry of Education, Science and Culture of Japan, under Grant General Research (C) 58550232 (1983).
Coded octal PSK system performance disturbed by imperfect recovered phase reference
Authors: Fujino Tadashi , Umeda Yoshiaki , Yamazaki Eizo 
Published: July 2007

AbstractThere have been various investigations on the PSK modulation technique which is encoded by a convolutional code. For the bandwidth constrained transmission, such as satellite communications, it is important to hold a high information transmission rate. From this viewpoint, the coded 8‐phase PSK (8PSK) system seems advantageous.This paper investigates the coded 8PSK system performance using the theoretical analysis and computer simulation when disturbed by the recovered carrier phase error and jitter. The results obtained here should be useful for coded PSK modem design.
Fault diagnosis of compartmental systems
Authors: Ohta Yoshito , Maeda Hajime , Kodama Shinzo , Itoh Takafumi 
Published: July 2007

AbstractThis paper investigates the fault diagnosis problems of compartmental systems from the viewpoint of linear algebra and graph theory. A system is considered faulty if a part of the system parameters (rate constants) takes an abnormal value. The problems of whether or not one can detect faults (fault detectability) and whether or not one can distinguish different faults (distinguishability) through observation of steady states are discussed. First, it is shown that the difference between the value of an observation vector for a faulty system and that for the normal system lies in a linear subspace corresponding to the fault, and a specific subspace is given. According to which linear subspace the difference in the observation vector belongs, a fault is detected and distinguished. Next, it is shown that conditions for fault detectability and distinguishability can be represented by using the dimension of the linear subspace corresponding to the fault and that an equivalent representation can be given in terms of the rank condition of a certain matrix. Finally, as the main result of this paper a representation is given for the distinguishability conditions on a compartment graph. In particular, when the number of the rate constants taking an abnormal value is at most one, these conditions can be replaced by directed path conditions which can be tested easily.
Tri‐reflector antennas with no cross‐polarized component
Authors: Urasaki Shuji , Makino Shigeru , Katagi Takashi 
Published: July 2007

AbstractSince offset antennas have good wide angle characteristics, they are used frequently for ground stations in microwave communications‐ However, when the frequency reuse is considered via two orthogonal polarizations, the cross‐polarization components generated on the reflector surface create a problem. A method was reported in which the cross‐polarization components are cancelled in the geometric optics sense in the offset Casegrainian and Gregorian systems. In such a method, the degree of freedom in design is not large. For instance, the inclination of the axis of the conical horn used as the primary radiator is restricted. This paper studies tri‐reflector antennas in which the degree of freedom is larger. The geometrical condition for eliminating the cross polarization is derived and the shape of the reflector system satisfying the condition is found. To confirm the theoretical results, an antenna has been constructed. The cross‐polarization components are less than about ‐30 dB and hence the validity of the theory has been confirmed.
Physical considerations on multimode oscillations using the probability density
Authors: Takase Fuyuto , Kuramitsu Masami 
Published: July 2007

AbstractIn an oscillator with multiple degrees of freedom using one active element, stable multimode oscillation is produced sometimes while only single‐mode oscillation is produced at other times, depending on characteristics of the active element. To account for this difference, the generation mechanism of multimode oscillation is discussed. First, the averaging procedure in time in the averaged potential method is represented as an expectation in terms of the probability density function of the voltage impressed on the active element. Using this expression, the probability density minimizing the averaged potential, i.e., the oscillation waveform, can be determined for the given element characteristics. Thus, the generation mechanism for multimode oscillation is described and the relation of the element characteristics to the conditions for the single‐mode or double‐mode oscillations can be presented. It is especially hoped that by using suitable element characteristics, a double‐mode oscillation can be produced with unequal amplitudes not presently known. Furthermore, several conclusions can be made with respect to general properties such as the fact that the double‐mode oscillation cannot be produced using only one active element with soft‐excitation properties.
Design of ARMA digital filters by simultaneous specification of magnitude and group‐delay response
Authors: Kunimoto Toshifumi , Aoki Yoshinao 
Published: July 2007

AbstractA method to design ARMA digital filters is proposed in which simultaneous specifications of magnitude and group‐delay are used. The properties of rational transfer function of z, and unique relation of magnitude and group‐delay response of minimum/maximum phase transfer function are presented. A design procedure is described based on these characteristics. The method consists of the Levinson‐Durbin algorithm and fast Fourier transform, which makes it very efficient in obtaining a recursive filter that has arbitrary magnitude and group‐delay responses.An example is illustrated for comparison with group‐delay compensation.
On products of two‐dimensional linear recurring arrays
Authors: Sakata Shojiro 
Published: July 2007

AbstractThe two‐dimensional linear recurring array over a finite field is one of the important subjects of study in error‐correcting codes and in discrete image models. In order to derive arrays or codes of a wider class from arrays or codes belonging to a class, not only linear operations such as sum, scalar product and shift, but also their combination with a fundamental nonlinear operation (component‐wise product) can be used. A theoretical investigation has been made of the algebraic properties of the product of one‐dimensional linear recurring arrays. The result of the studies has the practical implication that a direct‐product code of a cyclic code can be constructed with fewer shift‐register stages, using the product in the sense of this paper. This paper is to extend the fundamental properties of the product of one‐dimensional linear recurring arrays to the two‐dimensional case. The paper mainly discusses how the characteristic ideal I of the product G(I) = G(Ii) G(l2) can be determined for the additive groups G(Il) and G(I2) for the two‐dimensional linear recurring arrays defined by the polynomial ideals Ii and I2, respectively.