bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling by MDL criterion for adaptive data compression
Authors: Yokoo Hidetoshi 
Published: July 2007

AbstractThis paper proposes a high‐performance noiseless data compression model which can compress strings generated by a binary Markov information source without prior knowledge of the source. The adaptive expression of the existing universal codes is described by a model with separated sampler and encoder, and the learning structure of each code and the encoding process are described. Through such a discussion, the intuitive reasons are clarified as to why the codes, despite their asymptotic optimality, do not compress well at the start, pointing out room for improvement. Then, the MDL criterion is introduced into each encoder, to improve the performance, while keeping the sampler fixed. The MDL criterion is an estimation for the minimum code length, including the representation cost of the parameters. Based on this criterion, the Markov order which is to be assumed for each symbol is adaptively determined. Since the same determination can be made at the time of decoding, the unique decodability is guaranteed. In the second half of this paper, more detailed techniques are discussed, and a remarkable improvement is demonstrated by a computer simulation. It is also shown that the sampler of the proposed universal code is of a high‐performance, realizing two kinds of encoders.
A design method of fir filters suitable for SAW filters
Authors: Fushimi Shigeo , Morimoto Mikio 
Published: July 2007

AbstractThe surface acoustic wave (SAW) filter is usually designed as a finite‐impulse response (FIR) filter. The SAW filter, which faithfully realizes the arbitrarily specified amplitude and group‐delay characteristics, has been designed using linear programming, nonlinear programming and other techniques. In such design methods, the coefficients of the FIR filter are approximated iteratively. Consequently, a long computation time is required for a higher‐order FIR filter, and convergence is also a problem. This paper presents a design method which can realize a higher‐order FIR filter with arbitrary amplitude and group‐delay characteristics without using an iterative approximation. The design procedure is as follows: (a) the method by McClellan et al. is combined with the discrete‐Fourier transform (DFT) method, and the FIR filter with arbitrarily specified amplitude characteristics is designed; (b) for the group‐delay characteristics which are specified arbitrarily a cosine expansion is formed. By applying Bessel function, the FIR filter with the arbitrarily specified group‐delay characteristics is designed; (c) the two results are convolved and truncated to reach the required FIR filter. The design algorithm and example are presented. An SAW filter was constructed for the video signal extraction using an LiTaO3 substrate. The frequency characteristics and the electrode structure of the experimental filter are described.
Search for electromagnetic wave sources using the maximum entropy method
Authors: Kikuchi Jun'Ichi , Nagasawa Yoji 
Published: July 2007

AbstractUndesirable electromagnetic waves radiated from various electrical and electronic apparatus recently have become social problems. Research to prevent these effects is in progress in various fields. This paper presents a method of determining the location of electromagnetic wave sources two‐dimensionally. The analysis method is based on the deduction of the power spectrum by applying the maximum entropy method to time‐series information, i.e., the location of electromagnetic‐wave sources in two‐dimension, corresponds to the power spectrum. It is confirmed by computer simulation that the location can be determined with very high accuracy. The relationship between the amount of data measured and the accuracy of location determination, and the relationship between the accuracy of a source‐location detection and the offset of the measuring position, were examined. The number of measurements was found to be almost twice the number of electromagnetic sources, and the detection of the location of a source can have a very high resolution if the measuring position is kept at a high accuracy. The results show that this method is very effective in determining the position of sources, for example, radiated from a system consisting of subsystems.
Structural analysis of t‐invariance of petri nets
Authors: Onaga Kenji , Ge Qi‐Wei 
Published: July 2007

AbstractThis paper studies the t‐invariance of a Petri net by introducing two concepts of the rigidity for its existence and the marked‐graph‐reducibility for its efficient computation. Some characteristics and composition rules of rigidly connected Petri nets are given and an algorithm is designed to determine efficiently t‐invariants of a marked‐graph‐reducible Petri net.
On the multi‐commodity flow problem in certain planar directed networks
Authors: Nagamochi Hiroshi , Ibaraki Toshihide , Hasegawa Toshiharu 
Published: July 2007

AbstractThis paper introduces the concept of capacity balance (CB) to show that multicommodity flow problems for classes CB and CS (capacity semibalanced) directed networks have efficient graph‐theoretic algorithms.In a wide variety of applications, multicommodity flows are used to represent many important problems. Such applications include the assignment of traffic in roads or communication networks, and routing in VLSI design.For these networks it is possible to develop polynomial time graph‐theoretic algorithms. It is shown that the integral flow property holds for CB, and class CS networks, which are an extension of CB, are considered. As a special case, this class contains a certain multiterm, multistage production scheduling problem [3]. Its importance in practical applications is shown.
Multifrequency holography on near region using range curvature correction
Authors: Tajiri Katsuhiro , Sakamoto Yuji , Aoki Yoshinao 
Published: July 2007

AbstractThe authors have developed a radar to search an object buried in snow based on multifrequency holography. Multifrequency holography has a deficiency in that the quality of the reconstructed image is degraded. This phenomenon is called the range curvature. This paper proposes a method for correcting this phenomenon to obtain a correct image. The experimental results based on this method are presented. Multifrequency holography is based on the principle similar to that of the synthetic aperture radar. In both multifrequency holography and synthetic aperture radar, the range curvature is a problem. This phenomenon is especially significant in the near region. In this paper, this region is studied and the formula for range‐curvature correction and the simulation for confirmation of this formula, as well as the experiment, are introduced. Two experiments have been carried out with X‐band signals at 8.3 to 9.3 GHz for the object separated from the antenna by about 1 m. One of the experiments used a metal post while another used two metal posts. From these experimental results, it is confirmed that the range‐curvature correction is an effective method.
Almost‐periodic oscillation and generation of chaos in a parametric excitation circuit having an external force
Authors: Kitagawa Takaaki , Tomiyasu Ryuichi , Itoh Makoto 
Published: July 2007

AbstractThis paper considers the generation of almost‐periodic oscillation and chaos which occur in a parametric excitation circuit having an external force, and the region in which they occur.In a resonance circuit, if one of the reactances is excited with a frequency which is almost twice the resonance, a subharmonic parametric oscillation of one‐half order, i.e., the parametric oscillation for short, is sustained. If an external force with frequency near the resonance is applied to the circuit, the parametric oscillation disappears. The characteristics of this oscillation disappearance are analyzed by using the nonlinearized Mathieu equation with a forcing term which describes this system. For this we assume a solution containing only two harmonic components and apply the method of harmonic balance.In this paper, using a more detailed investigation of the characteristics of the oscillation disappearance, it is clarified that chaotic phenomena occur in a part of the response curves. Advancing the forementioned method, we obtain a set of four autonomous differential equations. Plotting the solution curve of these equations in the phase plane, we may investigate the behavior of this system. Consequently, it is clarified that under proper condition of circuit parameters, the solution curve tends to a limit cycle or chaos, by only several percent variation of the frequency of the external force. A limit cycle is correlated with an almost‐periodic oscillation. Therefore, the behavior of this system is revealed in more detail.
Radar clutter suppression schemes using multisegment MEM
Authors: Watanabe Hideaki , Azuma Ryuichi 
Published: July 2007

AbstractThis paper proposes a new adaptive suppression scheme for radar clutters. This scheme applies a multisegment MEM which has been known as a means for power spectral analysis and for classification of radar clutters. This adaptive suppression scheme is applied to the multisegment MEM based on the work by Zhang and Haykin who assumed that clutter data in neighboring range rings have a high correlation. Actual clutter data (ground, sea, and weather clutters) collected by an experimental L‐band radar with a low PRF wave were used. A comparison was made of performances based on improvement factors between the new suppression scheme for clutters and the suppression scheme used by Zhang and Haykin. The new processing method is shown to give an improved level by a few decibels for the numerical values of improvement factors. This was confirmed by the detection efficiency of an object signal which was buried in clutters using topological figures. It was clarified that the new suppression scheme for clutter possesses an enhanced capability in detecting the object signal easily compared with the method of Zhang and Haykin.
Design of three‐dimensional separable‐denominator digital filters via singular‐value decomposition
Authors: Hinamoto Takao , Hamanaka Takashi , Maekawa Sadao 
Published: July 2007

AbstractThis paper considers the situation in which the desired three‐dimensional impulse response is represented as a finite series, and discusses the spatial domain design of the three‐dimensional recursive digital filter, which approximates the desired response by a separable‐denominator three‐dimensional local state‐space model. As the first step, a necessary and sufficient condition is derived for the separable‐denominator three‐dimensional local state‐space model to be separately locally controllable and separately locally observable. It is shown that the condition is equivalent to the minimality of three one‐dimensional systems. Then the given three‐dimensional impulse response is represented formally in terms of three one‐dimensional impulse responses, and the coefficients of the separable‐denominator local state‐space model are designed through the singular‐value decomposition of the Hankel matrices. Finally, the validity of the proposed method is verified by a numerical example.
Variable region vector quantization
Authors: Matsuyama Yasuo 
Published: July 2007

AbstractGeneralized algorithms for vector quantization are presented and their convergences are proved. The generalized vector quantization is called variable region vector quantization since the method allows adjusted variable dimensional vectors covering variable subregions of source data.Algorithm I is the generalization of the LBG algorithm into the variable region case. This is called full‐gain variable region vector quantization. Algorithm II, on the other hand, is the variable region generalization of the gain‐shape type. The formation of each variable subregion is due to the grouping of elements so that the resulting set of variable dimensional super‐vectors has the minimum distortion to a given codebook. Algorithm III considers encoding‐decoding. Algorithm IV gives the suboptimal minimization for the alleviation of computational load.Methods presented here are applicable to various pattern handling including artificial neural nets. However, data compression terminologies are adopted in this research. All of the foregoing algorithms are introduced without any physical entity to data. Later, the cases of speech and images are discussed using their specific natures. The examples of the region optimization on speech and images are given.
Consideration on parallel type structure of IIR type adaptive algorithm
Authors: Kurosawa Kaoru , Tsujii Shigeo 
Published: July 2007

AbstractThe IIR type adaptive algorithm can be classified by its structure into the series‐parallel type and parallel type. Most of the FIR type adaptive algorithms can be applied to the series‐parallel type. However, this type has the problem that a bias error is produced in the estimated transfer function in the presence of observation noise. On the other hand, while the parallel type is expected to suffer less from observation noise, it may produce oscillation. It is difficult to insure the convergence and only the method by Landau is known. His method, however, necessitates matrix manipulation, which increases the computational complexity. Discussion has not been made on convergence when observation noise is present. This paper shows that the high‐speed least‐mean‐square method can be applied to the parallel type. In this method the computational complexity is small, being proportional to the number of coefficients. The convergences of the proposed method and the least‐mean‐square method applied to the series‐parallel type are analytically compared in the presence of observation noise.
Analysis of a nonpreemptive σ Mi/G/1(σ Ni) system
Authors: Takenaka Toyofumi 
Published: July 2007

AbstractHigh‐speed packet switching is a promising technology for multimedia communications in such wide‐band ISDN as speeches, images, and data. In this type of high‐speed packet switching, priority‐transmission technology will be effective, since a different packet‐transmission quality (e.g., transmission delay and loss‐rate) is required for each medium. This paper analyzes a nonpreemptive Mi/G/1( Ni) system which is the basis of the priority transmission system. In addition, n‐priority classes (where n is arbitrary) are treated using models of the Poisson arrival, general service‐time distribution, and individual waiting‐position type, while conventional analyses are limited to two priority classes. To obtain packet loss‐rate and delay characteristics, this paper analyzes mainly the marginal distribution of each priority class. The results of the analysis include an extension of the Cooper‐Gebhardt relationship which formulates the relationship between distributions at an arbitrary moment and after the completion of a service. For the packet loss characteristic and delay‐time characteristic and their approximate calculation methods, the reader is referred to the author's work in [6].
Characteristics and approximation methods of a nonpreemptive σ Mi/G/1(σ Ni) system
Authors: Takenaka Toyofumi , Akaike Takeshi , Takami Kazumasa 
Published: July 2007

AbstractHigh‐speed packet switching is a promising method in the wide‐band ISDN system for such multimedia as speeches, images and data. In high‐speed packet switching, conditions (e.g., transmission delay and loss rate) required for the transmission quality of packets are different in each medium. The priority‐packet transmission method will satisfy these conditions. This paper is based on the results of analysis of the non‐preemptive Mi/G/1( Ni) method [6], describes the evaluation of the characteristics of the priority‐transmission system, and proposes their approximation methods. Numerical computation of a three‐priority‐class model was carried out assuming such multimedia as speeches, images and data. The results show that:

It is possible to design the number of buffers independently for each priority‐class
the traffic characteristic of each Priority‐class is not affected significantly by changes of traffic ratio of the class Saving a higher priority than its own.
Two approximation methods are proposed: a method based on an approximation that marginal distribution is independent in ch priority class; and 2 a method using result (2); both methods are evaluated.
Vector correlation detection‐type interference canceller
Authors: Matsue Hideaki 
Published: July 2007

AbstractThe following is a method to eliminate an interference signal. The interference signal is obtained from the source, and the amplitude and the phase of the interference signal is adjusted to the same amplitude and the opposite phase of the interference component, and is added to the received signal. One important problem is how to control automatically the amplitude and the phase of the interference signal. This paper proposes a vector correlation detection‐type interference canceller for the digital system. An orthogonal error signal detector is employed which produces the in‐phase and quadrature error signals. Combining the circuit and the given interference signal, the correlation detection is performed between the two to perform the automatic control of the amplitude and the phase of the interfering signal. In the first part of this paper, the operation principle is described theoretically. Then, the configuration is shown. An experiment was carried out where the desired signal is 16 QAM or 256 QAM, and the interference signal is an FM signal (telephone 3600 ch.). The improvement factor was 26 dB for 16 QAM and 21 dB for 256 QAM. The control response was 50 to 140 ms. The result indicated the validity of the theory and the effectiveness of the proposed canceller.
Harmonic analysis of a capacitor‐filtered rectifier with line impedance
Authors: Kim Duk‐Gyoo , Nakajima Tatsuhito , Masada Eisuke 
Published: July 2007

AbstractAlthough the amount of harmonics generated from home electronic equipment such as televisions is small, the number of sets is large and they are used at the same time. Therefore, the harmonics generated from the power supplies of the electronic equipment is a cause of harmonic interference in the power distribution systems [1, 2]. In this paper, the input current of a capacitor‐filtered rectifier used widely as a power supply for electronic equipment is calculated with the impedance of the distribution system taken into consideration. As a result, an accurate expression became possible for the capacitor‐filtered rectifier current which had been treated by means of an approximate equation in the case where a line impedance, particularly inductance, exists [1, 2]. Also, an accurate prediction became possible for the current waveforms and harmonic behaviors according to the variations of the circuit parameters. The results computed as the parameters are varied indicate that the diode current path width, current waveforms and harmonic distributions, are strongly dependent on the inductance variation. The load circuits of a constant‐resistance type and of a constant‐power type were studied. As the inductance is increased, the harmonics are decreased whereas the amplitude and the average power of the fundamental wave are also decreased in the case of a constant resistance load. On the other hand, in the case of a constant power load, the amplitude of the fundamental wave tends to increase as the inductance is increased. When several of the capacitor‐filtered rectifiers are connected in parallel to a power distribution system, the amplitude of the harmonic cannot be evaluated by a linear sum of the harmonic contents of individual rectifiers.
Performance evaluation and optimization of ALOHA scheme with capture effect
Authors: Du Rongping , Nakanishi Hikaru , Tezuka Yoshikazu , Okada Hiromi , Sanada Hidehiko 
Published: July 2007

AbstractThis paper presents an analysis of the frame ALOHA scheme in the multiple‐access broadcasting channel with the capture effect, which has not been taken into consideration in past analysis. First, the transmission‐success rate, together with its expectation and variance, are determined, which indicate the basic performance of the group with various capture rates. The case is discussed where the capture rate is physically limited. Then two optimization problems are considered to maximize the number of terminals with access success. The first approach considers only a particular group, and a necessary condition is derived for the optimization of that group. Second, the performance of the whole system is improved, and the optimum solution is derived for the group assignment from the viewpoint of the capture rate. Finally, a discussion is made based on the numerical example, and it is shown that a higher throughput than in the past is realized in the multiple‐access broadcasting transmission with capture effect. Furthermore, it is shown that a higher performance is realized if all terminals are optimized utilizing the capture effect.
Multichannel CSMA/CD with hybrid load distribution/region distribution scheme
Authors: Ikebata Hiromi , Okada Hiromi 
Published: July 2007

AbstractA multichannel CSMA/CD scheme has been proposed which aims at utilizing the merits of CSMA/CD, a typical access control scheme in bus‐type LAN, while overcoming the demerits. For this multichannel CSMA/CD scheme, the following three schemes have been proposed: node distribution, region distribution, and load distribution schemes. First, this paper compares and discusses the proposed schemes, especially the load and region distribution schemes. The effective range for each scheme is determined. Then a hybrid load distribution/region distribution scheme is proposed which aims at improving the performance and enlarging the range of applications by dynamically switching between the load distribution and the region distribution schemes, according to the load level of the network.Discussions and qualitative performance evaluations are presented for the protocol, realizability and reliability of the scheme. It is shown that the load distribution/region distribution scheme in the multichannel CSMA/CD scheme exhibits a very satisfactory performance over the entire range of the load, with excellent reliability and expandability.
An adaptive orthogonal transform coding algorithm for images utilizing classification technique
Authors: Kato Yoichi , Mukawa Naoki , Okubo Sakae 
Published: July 2007

AbstractAn adaptive orthogonal transform coding algorithm utilizing the classification technique is presented. Coding efficiency for natural images can be improved by adjusting coding parameters in accordance with the local property of images. “Classification” is used to categorize small areas of an image into classes based on their characteristics. High coding efficiency results from changing coding parameters adaptively according to the classification index. Classification methods using ac energy, binary pattern and vector quantization index are compared, and the advantage of the classification method with the vector quantization technique is shown. Also, an orthogonal transform coding algorithm with an adaptive variable length coding method is proposed, and its structure and characteristics are described. A coding parameter normalization method to avoid mismatches between input images and coding parameters is also described. Coding experiments show excellent performance of this algorithm, for example, the number of bits for obtaining 40‐dB SNR of monochrome “GIRL” is 0.65 bits/pel, which is 20 percent smaller than conventional methods.