bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the synthesis of constant‐resistance distributed‐coupled‐line networks by stationary responses of periodic impulse train
Authors: Watanabe Toshiaki , Sakagami Iwata , Hatori Kozo , Kuri Takaki 
Published: July 2007

AbstractIn synthesis of multistage two‐wire conductor constant‐resistance distributed‐coupled‐line networks, a method had previously been applied in which the element values are determined from the transient response to the given unit impulse. Until now a method did not exist in which the network is synthesized from the stationary response to the periodic impulse train. This paper presents a method wherein the element values of the n‐section multistage constant‐resistance distributed‐coupled line network are determined from the stationary response to the periodic positive‐polarity impulse train 1 1 1 1 …, or both‐polarity impulse train 1 – 1 1 – 1 …. Simplification of this method is also discussed. The transfer function of the network considered in this paper has both the numerator and the denominator of nth order in z−1, and the element values of the network are uniquely determined from the transfer function. When the network is an all‐pass type, the element values may not be uniquely determined; this is discussed herein. The method of synthesis is simplified by utilizing the fact that, when the network to determine is of all‐pass type, the numerator and denominator of the network transfer function are inverse polynomials of z−1 to each other.
A fast computation algorithm of the two‐dimensional cosine transform using chebyshev polynomial transform
Authors: Morikawa Yoshitaka , Hamada Hiroshi , Watabu Kazuyoshi 
Published: July 2007

AbstractThe two‐dimensional discrete cosine transform (2D‐DCT) is the important orthogonal transform in the pattern recognition of images or highly efficient coding. This paper proposes a new method of fast computation for the 2D‐DCT for N × N (N = 2v) points. It is shown first that the 2D‐DCT can be reduced to a Chebyshev polynomial transform (TPT) and N 1D‐DCT's by rewriting the 2D‐DCT into the residue expression of polynomials. TPT is a polynomial transform with the same structure as the 1D‐DCT, which is defined on the polynomial‐residue ring P[z]/TN(z) with the Nth order Chebyshev polynomial TN(z) as the modulus. Then the successive factorization of the Nth order Chebyshev polynomial TN(z) on P[z]/TN(z) is derived, and by utilizing the factorization, a fast computation of TPT is derived. The computation of TPT is composed only of approximately 2N2 log2 N additions. Consequently, the algorithm of the 2D‐DCT proposed in this paper has slightly less than twice the high speed, compared with the traditional two‐column decomposition method necessitating 2N 1D‐DCT's.
Image signal processing LSI for facsimile
Authors: Tadauchi Masaharu , Tanno Kiyohiko , Hamada Nagaharu , Sato Kunio 
Published: July 2007

AbstractThe basic function of the facsimile reader is to correct the shading distortion (low‐frequency distortion due to low peripheral intensity) produced by the optical system in the analog signal from the one‐dimensional image sensor and to produce the correct black‐and‐white binary signal. Based on quantitative evaluation of the shading distortion, the authors developed LSI for signal processing, realizing a high‐precision binary signal transformation. The LSI first memorizes the shading distortion in the RAM in digitized form and then the information read from the RAM goes to the DA converter in synchronization with the input image signal. Comparing the reproduced analog distortion signal and the input image signal, highly precise distortion correction is realized. In this scheme the analog distortion is proportional to the input signal level and the operation can follow the change of source intensity and the change of manuscript background brightness. This function is realized by division between the reference voltage and the input voltage of the AD converter. The binary slice level is set with an accuracy within ±3%. The proposed LSI was fabricated by 5‐μm N–MOS technique and it was verified that the realized LSI satisfies the requirement for facsimile.
Degradation process and fluctuation mechanism of contact resistance for twisted conductor splice
Authors: Kuribayashi Masashi , Tokuda Masamitsu , Kawaguchi Tokihiro , Fujiwara Mitsugu 
Published: July 2007

AbstractDynamic and static properties of the contact resistance of twisted conductor splices have been investigated. The splice resistance in a static condition increases (degraded) with time. This is described in terms of a probability density function in which the logarithm of the splice resistance is regarded as a Markovian process. Furthermore, properties of the splice resistance when different mechanical qualities are involved in it are described by a composite probability density function. The theoretical prediction agrees well with observation. The dynamic properties are attributed to temporal change in the displacement of the conductors and in the contact force of the core conductors which is caused by an external force applied on them. Their dependence is given explicitly and a formula for evaluating the aging effect has been derived. Finally, the validity of this model is confirmed by the experimental results.
Signal smoothing by summation–generalized fejer method and generalized lanczos method
Authors: Imiya Atsushi , Sasaki Toshio , Ogawa Hidemitsu 
Published: July 2007

AbstractTruncation of a Fourier series causes ripples in the neighborhood of a discontinuous point. This is known as the Gibbs phenomenon. These ripples can be removed by the use of properly weighted Fourier coefficients. The smoothing is the summation method of the series theory applied to the Fourier series. The Fejer method is the Cesàro summation of series applied to the Fourier series. The Lanczos smoothing takes into consideration periodicity of the trigonometric functions. This paper extends the smoothing methods based on the summation so that they can be applied to general orthogonal functions. The Fejer method is developed as a weighted Fourier expansion, to which a geometrical explanation is given. It is shown also that the Fejer method yields a signal identified with a solution to a minimization problem. Periodicity of the trigonometric functions is extended to general orthogonal functions in such a way that the Lanczos method can be extended to cover them.
Minimax observers
Authors: Yahagi Takashi 
Published: July 2007

AbstractThis paper discusses the design of the regulator using output feedback, and describes a method of control using the observer. In the regulator using the observer, the evaluation function is increased, compared with the state‐feedback control. In this paper, the minimax evaluation is adopted, which considers the worst case in regard to the initial state. Consequently, the optimal observer, i.e., the minimax observer can be determined by the proposed method, in the sense that the worst value in regard to the initial state is minimized. Since the initial state is not known in the regulator problem using the output feedback control, the minimax evaluation is practically very important. This paper discusses first the discrete‐time system, and the design of the minimax observer is discussed for the linear quadratic form and the model‐following control problems. Then, the result of applying the idea to the continuous‐time system is shown. It is also possible to design the minimax observer for the continuous‐time system, in the same way as for the discrete‐time system. The proposed method can be applied, not only to the observer with the minimum dimension but also to the observer with the same dimension. As the numerical example, a solution of the minimum problem is presented using the proposed method.
A method for estimating biases in the measurement system of a height finding radar
Authors: Nagaoka Sakae 
Published: July 2007

AbstractAn analytical method is described based on data to be obtained by flight experiments for estimating biases of the range and depression angle measurement systems of a simple height finding radar (called NAMS) which uses a rotating fan beam antenna in a vertical plane. This method is based on the principle that the effects of biases on the height estimation error vary according to the geometric position of an aircraft relative to the radar head. Height estimation errors are estimated using the difference between the measured height of the aircraft by the radar and that by a barometric altimeter aboard the aircraft. Since the height estimation errors of NAMS can be approximated by a linear regression equation whose coefficients include biases of range and depression angle, the coefficients can be estimated by using the least squares method. In this paper, the derivation of the linear regression equation is given first. Then the algorithm for height estimation is described. Finally, the validity of assumptions and height estimation accuracy by the proposed method are examined by computer simulation. As a result, the feasibility of this method for estimating the biases of range and depression angle and the estimation accuracy is shown.
Electromagnetic wave excitation in a two‐dimensional impedance tunnel with a T‐junction
Authors: Uchida Kazunori , Matsunaga Toshiaki , Noda Takeaki 
Published: July 2007

AbstractAs an example of tunnels with a branch and a bend, the one with a T‐junction is selected for analysis of electromagnetic wave propagation when it is excited with a line source. As the boundary condition on the tunnel wall, a surface impedance approximation has been introduced. The calculations have been performed with the introduction of a two‐dimensional model. In the calculation, the tunnel is divided into the source region (Tunnel I) and the remainder (Tunnel II). The field in the former is modal expanded in a series with unknown coefficients; in the latter a Fourier transform is introduced so that the field is treated in the transform domain. The field matching at the aperture is performed in the Fourier‐transformed domain so that the unknown expansion coefficients described above can be obtained as the solutions of an infinite set of simultaneous equations. Finally, the numerical results are compared with those of a model experiment and the effectiveness of the surface impedance approximation is discussed. It is found that the numerical and experimental results agree rather well for the electric field intensity distribution in Tunnel II.
Analysis of the CSMA/CD protocol with deterministic contention resolution
Authors: Kimura George 
Published: July 2007

AbstractThe CSMA/CD DCR (CDMA/CD with Deterministic Contention Resolution) is a multiaccess protocol for local area networks. With this protocol a packet collides with another only once at most, so that high throughput and small delay characteristics are achieved. This paper presents a method of analyzing this protocol using a slotted model. First, for the equal arrival rate case, numerical results are obtained and the performance is evaluated on a throughput‐delay characteristic basis. As for the delay characteristic, not only its average but also its variance and distribution are evaluated. Also, the delay characteristics for right‐ and leftmost stations are clarified. Next, the unequal arrival rate case is analyzed and the delay characteristic is studied. Finally, the performance of CSMA/CD DCR is compared with those of CSMA/CD and token scheme, and the application field of CSMA/CD DCR is clarified.
Priority Exhaustive‐Service‐Type Multipacket Transmission
Authors: Komatsu Masaharu , Mayeda Wataru 
Published: July 2007

AbstractMultipacket transmission achieves higher channel utilization efficiency than single‐packet transmission, and also improves packet delay. Some multipacket transmission systems have been proposed. However, none has been proposed yet which takes account of priority level. This paper proposes a Priority Exhaustive‐Service‐Type Multipacket Transmission (PESMPT) method. This method is modeled as an exhaustive‐service‐type queueing system having traffic sources with different priority levels. We analyze PESMPT for the case of two priority levels and derive channel utilization efficiency, number of packets in a frame, packet transmission delay, etc. Also, from numerical examples, the performance of PESMPT is clarified and is compared with those of non‐priority exhaustive‐service‐type multipacket transmission method and HOL priority method which is the most general single‐packet transmission method with priorities.
Concept of space modification and a theory of function measuring the centrality (or mediality) of a point in a network
Authors: Shinoda Shoji , Sengoku Masakazu 
Published: July 2007

AbstractOften, in a system with a network structure, such as the communication network, traffic network and social relationships, the centrality of a point is discussed. The centrality of a point is usually measured by its relation to other points, and the distance has been used as a measure for the relation. Recently, a method based on the capacity has also been proposed. In contrast to the past theory of centrality function, which discriminated the cases into the relation between points into the distance and the capacity, this paper presents a unified theory by introducing the concept of modification of the space with respect to a point. Based on the modification of the space, the axiomatic system concerning the centrality and semi‐centrality functions are newly defined, extracting the properties shared by the past centrality functions. The characterization of the real‐valued function defined on a point is made based on the proposed axiomatic system, and it is shown that the proposed theory includes the past major results concerning the centrality function. Finally, the theory is applied to the network, where the weight is assigned to the point, and the length and capacity are assigned to the edge. Thus, the theory is a generalization of the centrality function which is applicable to the network, where weight is assigned to the point and the length and capacity are assigned to the edge.
Vector quantization of speech signals using principal component analysis
Authors: Kohata Minoru , Sone Hideaki , Echigo Hiroshi , Takagis Tasuku 
Published: July 2007

AbstractA new method of designing a vector quantizer is presented for bandwidth compression of speech signals, and some experimental results are shown. In this method, spectral parameters are extracted first from the DFT spectrum of input speech signals using a psychological frequency scale‐the so‐called Mel scale. This parameter is called the Mel‐scaled spectrum. The number of Mel‐scaled spectrum is reduced and the cepstrum of this parameter is calculated. Then this Mel‐scaled cepstrum is vector quantized and the codebook‐vector of the vector quantizer is determined by the algorithm using principal component analysis. With this algorithm, codebook‐vectors can be designed considering the statistical characteristics of the Mel‐scaled cepstrum. Also, the reduction of parameters by Mel‐scale can decrease the size of the codebook memory without greatly degrading the synthesized speech quality.Using the forementioned method two codebooks are designed: one contains 256 vectors, and the other contains 2048 vectors. The quantization error is compared with those designed by the well‐known LBG algorithm. The simulation results show that the codebooks designed by the proposed method present less quantization error and degradation of synthesized speech quality than those designed by LBG algorithm.
Optical observation of finite amplitude ultrasonic fields
Authors: Nishida Yukihiro , Asada Ichiro , Nakajima Masato , Yuta Shin‐Ichi 
Published: July 2007

AbstractWhen a coherent light is passed through an ultrasonic field of finite amplitude, the diffraction spectrum has an asymmetrical form around the Oth order component due to the harmonic generation corresponding to the waveform distortion in the propagation of ultrasound. This paper demonstrates that the asymmetry depends on the phase relationships among the harmonic components of the ultrasound. A method is proposed which can reconstruct the original ultrasonic waveform by a simple measurement and calculation. The method is to separate the symmetric and antimetric components of the diffracted light by calculating the sum and difference of the positive‐ and negative‐order components, and to determine the amplitude and phase from the sum and the difference, respectively. Using the proposed method, the CT techniques are applied to the optically measured data which are a line‐integral of the ultrasonic pressure. The ultrasonic field distribution is visualized for arbitrary cross section for each harmonic component, making it possible to observe the two‐dimensional distribution of the harmonic generation accompanying the propagation of finite amplitude ultrasound.
Numerical analysis of transmission lines with branches and junctions
Authors: Ichikawa Satoshi , Nakamura Yuichi 
Published: July 2007

AbstractSome of the analyses which are important in practice are: the analysis of induction noise between lines on the printed board; and the analysis of extraordinary phenomena in the multiline transmission system. These problems can be reduced to the transient analysis of the transmission‐line network composed of a number of transmission‐lines with different phases, their branches and junctions, as well as a number of lumped‐constant elements. By the analysis in the s‐domain through Laplace transform, the general solution for the basic equation for the transmission‐line is obtained containing arbitrary constants, and the arbitrary constants can be determined from the system of linear equations derived from the boundary conditions. This paper presents a method of deriving this system of linear equations for the case with only lumped sources and for the case with distributed sources. By determining the arbitrary constants, the solution is obtained in the operator domain, and the time‐solution is obtained by the inverse transform. The solution in the time‐domain is obtained by the numerical inverse Laplace transform, and the computation is performed by substituting a sequence of complex values into s. The effectiveness of the proposed method is verified by applying the method to several examples.
An adaptive equalizer based on parallel computation scheme
Authors: Hashimoto Koichi , Kimura Hidenori 
Published: July 2007

AbstractEqualizers which compensate the transmission characteristics of the transmission channels are important for ensuring the quality of data transmission and are inevitable especially in the data transmission using telephone networks.This paper describes a method of applying the parallel architecture (PA) which we have already proposed to an adaptive equalizer which utilizes the recursvie least square (RLS) method. The RLS method which is used to estimate and update the parameters of equalizers, is attractive as an effective algorithm because of its fast conversion. However, the complexity of its computation makes this method less popular than the least mean square (LMS) method, especially for adaptive equalizers which require the fast update of the parameters.Utilizing the parallel architecture with the method described herein it is able to execute the RLS method with the same amount of calculation time as that of the LMS method. The parallel architecture is expected to be applicable in practice because it has an architecture of regular structures and localized interconnections which are suitable for implementation in VLSIs.
An analysis of the multi–channel CSMA/CD protocol by non–slotted model
Authors: Kimura George 
Published: July 2007

AbstractThe multi‐channel CSMA/CD (M‐CSMA/CD) is a multiple‐access protocol which is suitable for broadband bus local area networks consisting of parallel channels. This protocol can achieve such good characteristics as a large capacity and a high degree of adaptability. Most of the CSMA/CD and M‐CSMA/CD protocols have been analyzed by slotted models in the past. There is one customer at a terminal (finite source) and he sends and/or receives data by the M‐CSMA/ CD protocol. The time required for the transmission start to be detected by another terminal within the same network is approximated by an exponential distribution, resulting in an irreducible Markov model. This paper presents a method of analyzing this protocol using a non‐slotted model. Numerical results are compared with computer simulation results and the approximation accuracy is discussed. The difference of the numerical results for non‐slotted models from those for slotted models is also discussed.
Synthesis of stray‐insensitive switched‐capacitor circuits which realize several transfer functions simultaneously
Authors: Nishi Tetsuo , Kunihiro Takushi 
Published: July 2007

AbstractIt is important in implementing circuits as LSI to realize several transfer functions by a single circuit. This paper considers a problem of realizing simultaneously several transfer functions with the same denominator polynomial by a single stray‐insensitive switched‐capacitor circuit, and presents a synthesis method. First, we derive a standard form of a system equation realizing 2n transfer functions of z−1 of degree n. Then we propose a technique for realizing the system equation as a stray‐insensitive switched‐capacitor circuit. As a result, it is shown that the 2n transfer functions above are realized by at most (2n + 3) (n + 1) capacitors and at most (n + 1) operational amplifiers. Finally, two examples are presented for stray‐insensitive switched capacitor circuits realizing four transfer functions of degree 2: one is realized by using two operational amplifiers, and the other needs three operational amplifiers.
Performance degradation of PN matched filter with clock frequency offset and its compensation
Authors: Hasegawa Takaaki , Nakagawas Masao 
Published: July 2007

AbstractOne of the important problems in the spread‐spectrum communication system is the despreading of the received signal in the receiver. The CCD delay‐line matched filter is a kind of device realizing the despreading. It has a problem in that the sampling frequency must be exactly the same as the clock frequency of the spread signals contained in the received signal. When there is an offset between the two frequencies, the performance of despreading is degraded in the delay‐line matched filter. However, for this problem, no quantitative analysis has been made so far. This paper presents a theoretical analysis by the new method and under several assumptions, for the degradation of the peak output in the CCD delay‐line matched filter when there exists an offset of the clock frequency. The results are compared with the results of computer simulation. Based on these results, a CCD matched filter loop is proposed which has the function to follow the various frequency offsets. Its performance is demonstrated by the simulation.
Four polarizations filter for frequency reuse
Authors: Umehara Tadatoshi 
Published: July 2007

AbstractAs a means to remedy the crowded use of frequencies in wireless communication, a system based on the orthogonal two‐polarizations with the same frequency is employed, which doubles the frequency utilization. This paper proposes a method which increases the use of the frequency by four times by using the four‐polarizations, adding two‐polarizations between the orthogonal polaritions. For this purpose, a device is needed which can select one of the four polarizations at the single frequency. The principle of the polarization rotation device to be used for such a purpose is described. The device is shown by an experiment to be practically useful.