bluuebunny/crossref_metadata_2025_split huggingface dataset:
A queueing system with server's walking‐time and serial service
Authors: Fukagawa Yukinori , Yanaru Torao , Yoshida Sho 
Published: July 2007

AbstractThis paper considers two queueing systems with the server's walking process, where the service of the job is composed of more than one serial process. The first system is the scheme where the server arriving at the station serves in the last service stage for a job. The second system is the scheme where the server arriving at the station can serve more than one service‐stage from the last to the first stage in the reverse order. When a job goes through a service at a certain stage, either it proceeds to the next service stage or leaves the system, following a specified probability. For both systems, the case of three serial stages in the stationary state is considered where the service time and the walking time follow general distributions. For the first system, the generating function for the number of jobs at the arrival of the server, the generating functions for the number of jobs at the departure of the job, queue waiting time and the stationary‐state condition are derived. For the second system, the equilibrium equation is presented for the generating function of the number of jobs at the arrival of the server, but the explicit solution is not derived.
Hierarchical coding method of still pictures with component separation
Authors: Ishibashi Satoshi , Ogura Kenji 
Published: July 2007

AbstractIn the interactive information retrieval system using images with wide areas such as aerial photographs, in general, it is difficult to display the entire image with a sufficient resolution because of the limited number of pixels that can be displayed by the device. Consequently, it is desirable in such a system that an arbitrary subarea of the image can be retrieved and displayed with a high speed. From such a viewpoint, this paper proposes and discusses the hierarchical component separation coding. In the proposed method, the image information is separated into two components such as the gray level and the resolution components in the block truncation code, and the two components are coded hierarchically in regard to the resolution from rough to detailed levels. By this scheme, an arbitrary part of the image can be retrieved and displayed with the specified resolution. An experiment was made by computer simulation, wherein the block truncation code is applied to the proposed code. It is shown that hierarchical representation of the image in regard to the resolution as well as the code compression of one‐half to four‐fifths can be realized. It is shown also, by applying the proposed coding to the actual image retrieval system that, the code complexity in terminal transmission for the retrieval of the object image can be reduced from one‐fifth to one‐half the traditional method, leading to a high‐speed retrieval and display.
Equivalent transformations and sensitivity of wave digital filters
Authors: Watanabe Eiji , Nishihara Akinori 
Published: July 2007

AbstractWave digital filters (WDF's) are well known to have a low‐sensitivity property in general. In addition to several existing design approaches, new circuit realizations of series and parallel sections are proposed in this paper. Also, equivalent transformations are presented which enable new WDF's to be derived from those of Fettweis. Accordingly, many kinds of equivalent WDF's can be designed from a single analog prototype filter. The comparison of sensitivity characteristics of these circuits shows that far less sensitive WDF's can be realized by an appropriate choice from the conventional and the new sections depending on the value of their internal multiplier coefficients.
An array fed multibeam antenna using equal phase–shift active elements
Authors: Egami Shunichiro , Kawai Makoto 
Published: July 2007

AbstractA multibeam antenna allows a large communication capacity and is suitable for satellite‐borne instrument. The present paper proposes a new array antenna with a reflector. The array is composed of active elements with equal phase shifts and is spatially fed by a multibeam horn. The array emits a spherical wave to a reflector. Its compact size fits satellite‐borne instrument and at the same time a good quality is expected for the gain and the sidelobe properties. Optimal values of the parameters are theoretically determined for S band operation with array construction, array position, number of elements, and apertures, and the properties of this antenna are derived. It is theoretically predicted that the space feed gives rise to a uniform power distribution over the elements. This prediction has been experimentally verified with a 19‐element array antenna. High power repeaters are no longer required and an arbitrary power distribution over the elements is readily realized.
A new image data compression method–extrapolative prediction–discrete sine transform coding (in the case of one–dimensional coding)
Authors: Yamane Nobumoto , Morikawa Yoshitaka , Hamada Hiroshi 
Published: July 2007

AbstractThis paper proposes the extrapolative prediction‐discrete sine transform as a new highly efficient coding for the gray‐level image. In the proposed method, an extrapolative prediction is made from the immediately preceding pixel to the present pixel block, and the prediction error signal is encoded by the orthogonal transform. Assuming that the information source for the image is a stationary first‐order Markov process in the wide sense, it is shown that the orthogonal transform which decorrelates the prediction error signal can be approximated by a certain kind of sine transform. An algorithm is presented for the high‐speed execution of this data. The rate‐distortion characteristic is discussed for the case of one‐dimensional coding, and it is shown theoretically that the coding efficiency of the proposed method is nearly the same as those of the discrete 16‐pixel cosine transform with block length of 4 pixels and the 8‐pixel fast Karhunen‐Loéve transform. Comparing the coding complexities of those methods, the proposed method is shown to be especially advantageous in the hardware realization. Computer simulations were made for actual images using the fixed‐rate coding and variable‐rate coding (entropy coding), and the result supports the idea.
Beam scanning characteristics of front fed offset cassegrain–type multibeam antenna
Authors: Makino Shigeru , Kobayashi Yuji , Urasaki Shuji , Katagi Takashi 
Published: July 2007

AbstractThis paper shows theoretically and experimentally that the front‐fed offset Cassegrain (FFOC) antenna is suited as a multi‐beam antenna to be borne on an international satellite. First, the problems are identified for conventional reflector configurations. Then the beam deflection characteristics are shown numerically in the case where an FFOC reflector surface is used as a multibeam antenna. The performance of the test antenna is confirmed experimentally. From the measured results of a test antenna of 120 wavelengths, it is found that the reduction of the gain in the beam deflection within a circle of the visible radius of 10° is less than 1.8 dB which agrees well with the computed results. The cross‐polarization level is less than‐34 dB. Because the cross‐polarization component generated by the primary radiator is −40 dB, the cross polarization generated by the reflector system is quite small.
Analysis of queueing systems with randomly changing population states
Authors: Fukuda Akira 
Published: July 2007

AbstractThe queueing system, in which the property of the population is changing randomly, frequently is observed in various problems, and it is important to know its property. However, the analysis of the characteristics of such a system in general is difficult. From such a viewpoint, this paper considers the simplest example of the M/M/1 system, where the inter‐arrival‐time distribution or service‐time distribution changes following a two‐stage Markov chain. A strict solution is derived for the behavior of the system. Using the state‐transition rate diagram of the system, the system equation for the steady‐state is derived. Then the z‐transform of the steady‐state probability distribution and the Laplace transform of the waiting time distribution are obtained. Their inverse transforms and the mean behaviors such as the mean number of waiting customers and mean waiting time are derived. Then the fundamental properties of the system are examined. For example, when the systems have the same mean load, the mean waiting time is longer if the load difference between the two states is large, or if the mean sojourn time at each state is long. These properties have been noticed by simulation, but they are verified quantitatively by analysis. However, in this paper the major aim is only to present an accurate method of analysis, and a detailed examination of the system is left for another paper.
Estimation of random modulating signals in transmission systems with nonlinearly coupled noises and additive non‐gaussian noises
Authors: Amano Masaaki 
Published: July 2007

AbstractNoise in a transmission system often is assumed to be additive to and independent of the signal of interest. This paper discusses estimation of random modulating signals, where noise is assumed to be either nonlinearly coupled to the signal or additive non‐Gaussian. Such noise appears in an optical link, biological system, or control system.
Structural analysis for instantaneous waveform by natural observation method
Authors: Iijima Taizo 
Published: July 2007

AbstractIt is fundamentally important in waveform recognition to provide a method for systematic description of the changing nature of the given waveform at an arbitrary time. This paper presents a solution to this problem based on the natural observation method proposed by the author. After the definition of the instance is introduced, regulating the infinitesimal time interval at the time of interest, the instantaneous derived waveform series is derived from the input waveform by successive observations. A set of practical analysis methods has been studied theoretically for determining the mathematical structure of the instantaneous waveform for the observations.
Bandwidth necessary and sufficient for the determination of a periodic quantized signal
Authors: Sakaniwa Kohichi 
Published: July 2007

AbstractThe periodic quantized signal in this paper is defined as a piecewise constant signal which has a finite number of jumps in a period and has constant levels between adjacent jumping points. Periodic quantized signals are classified into four groups according to whether the jumping points and/or the height of jumps at the jumping points are, respectively, restricted to integer multiples of prescribed quantities or not.This paper considers the two groups among them: (1) the set of signals whose levels {aK} between adjacent jumping points are allowed to take arbitrary real values but the jumping points {tk} are restricted to integer multiples of T/N, where T is the time interval of a period and N is the number of jumping points in a period (signal set III); and (2) the set of signals whose levels aK} between adjacent jumping points and jumping points {tK} are restricted to integer multiples of a specified step size δ and respectively (signal set IV). We have studied the smallest amount of Fourier coefficients required for the determination of the original periodic quantized signal having N jumping points in a period. Our results assert that the Fourier coefficients necessary and sufficient for the determination of the original periodic quantized signal are given by:

Up to the [N/2]th order for signals belonging to the signal set III, where [x] denotes the maximum integer not exceeding x.
Up to the N0 ( N/p1)th order for signals belonging to the signal set IV, where p1 is the smallest prime factor of N.
Local convergence of waveform relaxation method
Authors: Urahama Kiichi 
Published: July 2007

AbstractThis paper discusses convergence of the waveform relaxation method based on the decomposition of the circuit, and presents several sufficient conditions for the numerical procedure to converge locally. Then the block‐diagonal dominant property is defined for the block matrix, and some properties of the block‐diagonal dominant matrix are indicated. The algorithm in RELAX, which is a typical simulator based on the waveform relaxation method, is discussed. It is shown that the numerical procedure converges locally if the capacitance or conductance matrix is a block‐diagonal dominant matrix.
A newton algorithm for steady‐state analysis of nonlinear oscillatory circuits
Authors: Yamamura Kiyotaka , Horiuchi Kazuo 
Published: July 2007

AbstractFor the steady‐state analysis of nonlinear oscillatory circuits, the Newton algorithm proposed by Aprille and Trick is well known. However, often the conventional algorithm needs too many iterations or may not converge, because of the discretization error of numerical integration. This paper discusses in detail the Newton algorithm for the steady‐state analysis, and proposes an efficient algorithm which retains the quadratic convergence in the presence of the error of numerical integration.First, a method of computing the exact Jacobians of the functions obtained by numerical integration is proposed. Then it is shown that the quadratic convergence of the Newton algorithm is retained by suitably controlling the truncation errors of the inner Newton iterations for the corrector equations. The proposed Newton algorithm converges to a solution quadratically even if the step length of the numerical integration is large. Utilizing this property, a mesh refinement strategy is proposed which improves the computational efficiency of the algorithm by determining first an inaccurate solution which is computed by using a large steplength. Then this approximate solution is used for the starting point of the next Newton iteration with a smaller steplength to obtain an accurate numerical solution. Also, it is shown that the foregoing technique can also be applied to the Newton algorithm for computing the bifurcation value of the periodic solutions. The validity and the effectiveness of the proposed method are also verified by numerical examples.
An active‐r all‐pass circuit compensating influence with second‐order pole of the operational amplifier
Authors: Okine Mitsuo 
Published: July 2007

AbstractWith the widespread application of such transmission systems as TV and data transmissions, increasing demands are produced for wideband and high‐performance transmissions. As is well known, numerous all‐pass circuits without amplitude distortion are employed for the equalization of the delay distortion of the transmission channel. Several structures have been proposed which employ the operational amplifier, which is easy to construct and easy to design. A remaining problem, however, is that the operating frequency is low. This paper proposes a first‐order, active‐R, all‐pass circuit with a very simple structure and working frequency extending up to several hundred kilohertz. In this kind of circuit, the amplitude characteristics are affected adversely if the ratio of the center frequency and the second‐order pole frequency of the operational amplifier is large. In the construction in this paper, this effect is compensated to realize a wideband performance. Two methods of compensations are presented: (1) the compensation of the element values in the original circuit; and (2) adjustment of the divider ratio of the resistor‐voltage divider connected to the original circuit. Similar compensating characteristics are obtained by either circuit. However, the latter seems more desirable since the compensation can be made by a single variable‐resistor with less effect on the phase characteristics.
Radiation phenomenon from transmission lines of finite length
Authors: Kami Yoshio , Sato Risaburo 
Published: July 2007

AbstractThis paper presents analytically electromagnetic fields radiated from finite‐length transmission‐lines. The method is based on the fact that the measured power patterns radiated from the finite‐length transmission line are the same as that measured for the coupling, which is a phenomenon when a plane wave excites a transmission line. Under the hypothesis, reciprocity is assumed between the radiation and the coupling. The power radiated from the finite‐length transmission line, which is received by the measuring antenna, is obtained by the use of a circuit‐concept approach, the transmission‐line equation for the coupling. By comparing the computed values with the measured ones, the reciprocity between them is verified. A discussion is also made on the model with a bend, in addition to the straight line, to confirm the validity. As a result, the fields radiated from the finite‐length transmission line are determined from the power received by the antenna.
Transient analysis of electromagnetic field for resonance‐type absorber in three‐dimensional space
Authors: Aoto Tadahisa , Yoshida Norinobu , Fukai Ichiro 
Published: July 2007

AbstractTV and radar ghosts are becoming an increasingly serious problem, and the radio wave absorber has been developed to solve this problem. This paper presents a systematic analysis of reflection, scattering and diffraction of an electromagnetic wave which is incident on an object covered with a special radio wave absorber of resonance type. The basic formulation is given and the VSWR is calculated with a coaxial cable loaded with the absorber. The result shows the validity of the present method. The electromagnetic field is calculated near a square pillar with and without the absorber and, finally, the time evolution of a wave packet field incident on a square pillar is obtained.
Leapfrog‐type active RC filters with reduced number of operational amplifiers
Authors: Ishibashi Yukio 
Published: July 2007

AbstractIt is known that the active RC filter which simulates a ladder‐type filter has a lower element‐sensitivity than a cascade‐connected active RC filter. Many methods to construct this type of filter have recently been proposed. This paper introduces a method in which an active RC filter is used to realize the relationship between the node voltages and the closed‐circuit currents in a circuit obtained by scaling the impedance of each element of the original LC filter with the s‐function. By choosing the scaling function appropriately, the inverting‐integration circuit in a conventional leapfrog‐type filter can be replaced by an inverting double integrator with two capacitors; and the noninverting‐integration circuit in the same filter can be replaced by an RC first‐order, low‐pass circuit. This reduces operational amplifiers in the circuit to less than half a conventional leapfrog‐type active filter. The element‐sensitivity was analyzed, and the conditions for a low element‐sensitivity were obtained. A fifth‐order Cheby‐shev low‐pass filter was constructed, and its measured element‐sensitivity was compared with the results of a computer simulation.
Electromagnetic wave scattering by a plane metallic grating loaded with three dielectric layers
Authors: Uchida Kazunori , Noda Takeaki , Matsunaga Toshiaki 
Published: July 2007

AbstractIn this paper, electromagnetic wave scattering by a plane metallic grating loaded with three dielectric layers is precisely analyzed by use of a new type of spectral domain method combined with the sampling theorem. Two different polarizations, E‐ and H‐waves, are considered here. Induced surface currents on the conducting strips are expanded in terms of weighted Fourier series taking into account the field singularity near an edge and spectral expressions for the scattered fields are given. Then the unknown coefficients related to surface current expansions are solved in spectral domain by imposing the boundary condition associated with a conducting strip. Accuracy of the numerical results is checked in comparison with extrapolated values, and numerical calculations are carried out for frequency characteristics of reflectivity and transmittivity as well as surface current distributions. Insertion loss of dielectric layers is also described in connection with a polarization discriminator of antennas. Although we cannot compare the numerical results with the rigorous ones as in the case of no dielectric loading, it seems that the present numerical results are considerably good.
Boundary element formulation for sound field problems
Authors: Kagami Shin , Fukai Ichiro 
Published: July 2007

AbstractSince the sound field is a scalar field, the steady‐state field is expressed by a scalar Helmholtz equation. In application of the boundary element method to this problem, many techniques which have been developed in the two‐dimensional boundary element method can be used, and a technique of spherical trigonometry also is used in evaluating a solid angle. The radiation impedance of a breathing sphere which was evaluated by the present method agreed very well with the analytical value. The present method is applicable to other scalar wave fields as well as to vector fields if the boundary conditions are treated carefully.
The number of spanning trees in an iterative contact graph composed of general cells
Authors: Sato Kimio , Onodera Rikio 
Published: July 2007

AbstractThis paper derives a formula for the number of spanning trees in a contact graph with an iterative structure having k general graphs as cells. Mainly, the cascade, wheel, and prism types of contact graphs which are representative among them, are considered. Until now, G has been restricted to an m‐ cycle Cm or n‐point complete graph Kn, and the calculating formula of electrical networks has been applied to unit‐conductance networks of these contact graphs. Then by considering the equi‐electric potential property, etc., the number of spanning trees with k and m or n being variables has been derived. When cells are general G, however, there are no variables corresponding to m and n because of the instability of its structure. Therefore, in this paper we use the formula between conductance of each branch of a network obtained by equivalence transformation of G into K3 or K4 with respect to vertices of G concerned with contact, that is, contact points and the numbers of spanning trees of G and graphs constructed by shorting contact point pairs of G. Also, we represent traditional point‐contact and branch‐contact in the extensive manner of s‐contact by adding s‐multiple branches to contact portions of contact graphs. In other words, the number of spanning trees of these contact graphs is given by a function of the numbers of spanning trees of G and graphs obtained by shorting specific contact point pairs of G and k and s. Furthermore, this result can be applied directly to the derivation of the formula for the summation of all possible tree admittance products in an admittance network which has no mutual coupling with the forementioned graphs as its interconnection structure.
Traffic characteristics of multimedia packet‐switching system with sources generating packets in bursts
Authors: Takenaka Toyofumi , Akaike Takeshi 
Published: July 2007

AbstractIn a multimedia packet‐switching system handling voice, moving images, data, etc., the bursty traffic generated by moving image terminals can have an unfavorable effect on the traffic quality of other media. To avoid this problem, the handling of bursty traffic should be established.In this paper, the packet bursts are modelled by a batch arrival and the effect of burstness on packet overflow characteristics is examined by analyzing batch arrival queueing systems with finite waiting rooms. The results obtained are summarized in the following.(1) To achieve the practical range of packet overflow probabilities (e.g., 10–6) in a system handling burst traffic only, a high buffer size indicator k (the ratio of the buffer size to the number of packets in a burst) is needed to utilize the transmission lines efficiently.(2) To provide efficient utilization of the transmission lines and to realize practical packet overflow probabilities (e.g., 10−6) in systems transmitting a mixture of burst and nonburst traffic, the share of burst traffic should be very small.