bluuebunny/crossref_metadata_2025_split huggingface dataset:
Speech quality of adaptive delta modulation (ADM) codec with syllabic companding
Authors: Itoh Kenzo , Kitawaki Nobuhiko , Kakehi Kazuhiko , Hayashi Shinji 
Published: July 2007

AbstractDelta modulation with syllabic companding is one of the voice digitalization systems for which experimental studies have been conducted to evaluate speech quality. First, appropriate circuit constants are provided by use of the objective evaluation measure S/NO for the experiments and then studies are made on the features of the quantization noise in the system. Second, the cepstrum distance measure obtained from linear prediction analysis is introduced as an objective evaluation measure and its relationship to subjective evaluation is also studied. The following conclusions are made. (1) Lowering the sampling frequency to 32 kHz has little effect on articulation and can provide fair or better than fair quality if appropriate signal input levels and received speech volumes are maintained. (2) The effect of circuit noise at about 2.0 mV at the encoder input on voice articulation is deemed to be equivalent to having the same circuit noise at the decoder output. (3) The detectability threshold of transmission errors is about 2.4 × 10−4, which proves that the system is less prone to code errors than the log‐PCM system. In addition, the coincidence of the cepstrum distance measure with the subjective evaluation value is better than that of the segmental SNR.
Analysis of monopole antenna erected on circular conductor
Authors: Iwashige Jiro 
Published: July 2007

AbstractA vertical monopole antenna erected on the base of a circular cone is analyzed by the equivalent edge current (EEC) and the geometrical theory of diffraction (GTD). The cone may be converted into a disk, column or truncated cone. The current distribution and input impedance are calculated by the moment method. The multiple diffraction on the circular plane is considered in the calculation of radiation patterns by the EEC method (or GTD). The experimental results agree approximately with the calculation.
Hierarchical structure of telecommunication network with independent transversal trunks
Authors: Akiyama Minoru , Tanaka Yoshiaki , Yamashita Mikio , Iio Makoto 
Published: July 2007

AbstractThe main objective of setting up the hierarchical structure for telecommunication network is to concentrate the traffic in order to increase the efficiency of transmission lines, thereby reducing the total cost of the network. The optimum structure of the network is determined by such factors as traffic, its flow pattern, the costs of transmission line and switching equipment. The costs of components of the switching network change rather rapidly due to recent technological development. The change of cost and the role of transversal trunks in handling traffic calls have made the reconsideration of installing transversal trunks worthwhile. This paper presents a geometrical model for the Japanese public telephone network. The optimization of the hierarchical structure of the network is performed taken into consideration such parameters as costs of transmission lines, switching facility, and traffic threshold for transversal trunk. It is concluded that the three‐stage network with end offices, toll centers, and district centers seems appropriate in the near future. The district center of this network should be about the same scale as the existing regional center. The traffic threshold for installing the transversal trunk should be almost several tens of erlangs.
Theoretical method for the analysis of queueing system with overflow traffic
Authors: Matsumoto Jun , Watanabe Yu 
Published: July 2007

AbstractThe theoretical analysis and design of queueing systems with overflow traffic are presented. The non‐random traffic is approximated by an interrupted Poisson process with which the 3‐moment matching method is used for obtaining the average, variance and the 3rd‐order moment. The analysis of a queueing system with finite capacity with overflow traffic can be considered to be a G/M/1 type queueing matrix to which the interrupted Poisson process and known equations apply. For analysis, the overflow traffic moments and formulas for the overflow probability and average waiting time of the finite‐capacity queueing system with overflow traffic are so derived that they can be used in their practical forms very easily. In the case of finite‐capacity queueing systems, the theoretical overflow probability and average waiting time are derived for single‐ and multiple‐overflow traffic models, overflow and random traffic models as well as the two‐stage overflow traffic model. From comparison with the simulated experimental values, the accuracy of the theoretical approximations is shown to be excellent.
Simultaneous realization of some system matrices by networks containing switches
Authors: Nishi Tetsuo , Iwasaki Kazuto 
Published: July 2007

AbstractThis paper discusses simultaneous realization of some system matrices Fi defined by x‐y =f1 x‐y where × is an n‐dimensional state vector, by a network composed of resistors, capacitors, amplifiers and switches. Based on a weak assumption, we obtain the following results: (1) The minimum number of switches required for realization of F1 and F2 (or F1, F2 and F3) equals r(F1 − F2) (the minimum value of r(H1) + r(H2) + r(H3) where r(A) denotes the rank of a matrix A and Hi (i = 1, 2, 3) satisfies F1 − F2 = H1 + H2 and F1 − F3 = H1 + H3; (2) At most (n + 1) amplifiers are required; (3) There is an example in which (n + 1) amplifiers are required.
Nonreciprocal devices in open‐boundary structures for millimeter‐wave integrated circuits
Authors: Muraguchi Masahiro , Naito Yoshiyuki 
Published: July 2007

AbstractAlthough a number of components for millimeter‐wave integrated circuits based on an open dielectric waveguide have been proposed, little has been reported on nonreciprocal devices and no significant results have been obtained. In this paper we discuss experimental verification of nonreciprocal propagation phenomena in an open ferrite waveguide and their application to open nonreciprocal devices. Based on the results, we propose a circulator of directional coupler type which makes use of nonreciprocal propagation phenomena in an open ferrite waveguide. We also propose a pillbox resonator type circulator and a junction type circulator using the nonreciprocal resonance of an open cylindrical ferrite. Circulators of the directional coupler type and the pillbox type do not need any conductor in principle. The radiation loss can be reduced without significant increase of the conductor loss if a conductor shield is used in the E‐plane of the junction circulator. A junction circulator with practical characteristics is developed for millimeter‐wave integrated circuits.
Considerations of a multi‐address message delivery system consisting of multiple centers
Authors: Takenaka Toyofumi , Yoshida Yutaka , Saito Joichi , Watanabe Naoya 
Published: July 2007

AbstractThe multi‐address message delivery system is a communication technique for sending identical messages to plural addresses and is applicable to various information such as in data transmission, facsimile or even voice. It is promising as one of the important communication techniques for office automation. In this report, we take up a multi‐address message delivery scheme in which there are plural multi‐address message centers in a network. We compare two message delivery systems from centers to addressed terminals. One is the source center delivery system by which direct transmission is made at a source center to which a multiaddress delivery has requested. The other is the destination center delivery scheme by which transmission is made from a destination center via the source center. It is concluded that the source center delivery scheme is preferable with respect to the costs of processing and storage in the center, while the destination center delivery scheme is prefereable with respect to the cost of transmission between service areas. Further, the network cost, which is the total of both, depends on various conditions and, accordingly, their application regions are shown.
A light intensity modulator using p‐n junction
Authors: Ohke Shigeaki , Kusunoki Akira , Cho Yoshio , Matsuo Yukito 
Published: July 2007

AbstractThis paper investigates the basic operation of a new type of cut‐off optical modulator using a GaAlAs layer on a GaAs substrate as waveguide whose p*nn* structure is suitable for monolithic optical devices. A new numerical solution for the field in the depletion layer of a reverse‐biased pn junction diode is presented. This method is applied to the above‐mentioned cut‐off type optical modulator for calculation of the field in the two‐dimensional layer as the modulation space. For the modulator a three‐layer slab structure is assumed and the modulation is analyzed with respect to the applied voltage by the method of eigenmode expansion from the waveguide viewpoint. Results show that for a modulator with length of several mm modulation of 90% and above can be achieved.
On pair relationships in time‐division switching network
Authors: Saito Tadao , Ogino Nagao , Goto Fumihiro , Inose Hiroshi 
Published: July 2007

AbstractSince a PCM transmission path can carry voice signals in one direction, the time‐division switching network at any PCM telephone exchanges employs a four‐wire configuration. Therefore, a pair of paths is required to form one connection. A general way of preparing such pairs is to establish the pair relationships between switches or links in the switching networks and to create paths automatically based upon those relationships. Having implemented these pair relationships, the blocking probability, the amount of path hunting and the required amount of control hardware for switching networks can be reduced considerably. Pair relationships are quite important in the efficient composition of time‐division switching networks. However, no general theory exists yet for the pair relationships. This report presents an overall study on the pair relationships in time‐division switching networks. First, we define the pair relationships and classify them into several forms and then present practical examples. We then describe how to compose the more important pair relationships and briefly review the connection patterns that are produced by forming the pair relationships and modifying link connection patterns. Finally, we explain how to compose favorable pair relationships based on the above study conclusions.
New doubly orthogonal functions and their application to pattern synthesis
Authors: Tokumaru Shinobu , Nakahara Masatoshi , Yamamoto Shigeru 
Published: July 2007

AbstractThe double orthogonality of spheroidal wave functions has been used in pattern synthesis. However, because of difficulty in calculating spheroidal wave functions and in determining double orthogonality, its application to pattern synthesis is limited. In this paper, a new eigenintegral equation is derived to obtain general doubly orthogonal function systems in which the integral section and weighting functions can be determined freely. The new doubly orthogonal functions are applied for pattern synthesis under constraints.
Application of bifurcation theory to nerve excitations
Authors: Toko Kiyoshi , Nitta Junsaku , Urahama Ki‐Ichi , Yamafuji Kaoru 
Published: July 2007

AbstractAn expression for the amplitude of stable steady self‐oscillatory solutions for the inverted bifurcation is obtained by applying bifurcation theory to the BVP equation, which is a model describing nerve excitations. Up to the fifth‐power term with respect to the amplitude is included in the calculation, assuming that the amplitude of the steady self‐oscillatory solution is of small order. The obtained expression for the inverted‐bifurcation can continuously be transformed, leading to an expression for the normal‐bifurcation by merely varying one parameter. Further, utilizing that expression and employing the reductive perturbation method in which the amplitude is regarded as an infinitesimal parameter, an expression describing the relaxation phenomenon in the neighborhood of the stable steady solution is derived for the inverted‐bifurcation as well as for the normal‐bifurcation, the nature of which is close to that of the inverted‐bi‐furcation. Since this expression has the form of the usual time‐dependent Ginzburg‐Landau(TDGL) equation and an additional term, the behavior of those bifurcations which considerably differ from the usual normal‐bifurcation can well be described by the derived expression.
An integral equation for electromagnetic wave scattering from a dielectric cylinder
Authors: Chiba Michitane , Ishiai Teizo 
Published: July 2007

AbstractThis paper describes an analysis of the problem of electromagnetic scattering by a dielectric cylinder with an arbitrary cross section by means of an integral equation a‐long the boundary. The integral equation used by Wu and Tsai for two‐dimensional boundaries for TM‐wave scattering from biological bodies is superior in simplicity to Muller's integral equation. However, the solution to the former has the disadvantage that it is susceptible to resonance of the interior region. To remove such resonance, it is effective if the boundary conditions are extended so that additional equations are included which ensure that the field inside the scatterer is zero. However, a basis for selecting the interior points is not clarified. On the other hand, for problems involving conductors, it is well known that mixing of the resonant solutions occurs in the process of solving the integral equation on the boundary. A number of methods have been reported on the construction of integral equations unaffected by the interior resonance. From this point of view, an integral equation is derived which satisfies all the boundary conditions from the integral equation by Wu and Tsai. By means of numerical calculations, it is confirmed that this integral equation is not affected by the interior resonance.
Surface fields excited by a vertical electric point source located on a conducting concave spherical surface
Authors: Inami Kazuyoshi , Sawaya Kunio , Mushiake Yasuto 
Published: July 2007

AbstractWith the appearance of dome antenna in recent years, the necessity for analyzing the electromagnetic fields produced by a wave source placed on the concave side of a solid conducting surface has arisen. Some research on this problem for a conducting concave cylindrical surface has beem reported. However, no research which is of practical importance, has been conducted on the concave sphere. This paper describes the result of an analysis of the surface magnetic field produced by an electric point source placed on the concave side of an open conducting sphere. The analytical technique is based on the case of a concave cylindrical surface. First, a wave component traveling along the boundary is obtained from a representation of the field inside a closed conducting sphere and the field representation for an open sphere is derived. Next, the surface magnetic field for the case where the radius of the sphere is sufficiently large compared to the wavelength is represented in the form of the fields of geometrical optics and integrals. As in the cylindrical case, the result of concrete calculation shows that the resulting field agrees with the field near the wave source in the case of a vertical electric point source placed on an infinite ground plane and that a complicated interfering pattern is produced at a distance far from the wave source. Also, the appropriateness of this analytical result is confirmed through an experimental study.
Modeling and analysis of an intersection on AGT
Authors: Hamamatsu Yoshio , Nakada Katsuhiro , Kaji Ikuo , Doi Osamu 
Published: July 2007

AbstractA model for automated guideway transit (AGT) is proposed, formulating the behavior of traffic at an intersection using the Markov chain technique. It is assumed that the intersection is composed of overpasses and underpasses and the traffic from the sub‐line to the main line goes through an offline. The vehicles coming from the subline must form a queue in order to avoid colliding with the vehicles through the main line, but the queue cannot be made indefinitely long, considering its effect on the following traffic. Two kinds of restrictions on the queue on the subline are considered, which are (1) restriction on the number of vehicles in the queue (model I), and (2) restrictions on the number of vehicles in the queue and the waiting times (change of MT) of the top vehicle (model II). The relation between the incoming vehicles in the main line and subline and the behavior of traffic at the intersection (average number of vehicles in the queue and the derouting rate) are discussed.
Spatial decay properties of L‐type horizontal cell response in the retina
Authors: Fukurotani Kenkichi 
Published: July 2007

AbstractThis paper discusses the propagation of potentials in the receptor field of horizontal cells in the retina and the linearity of response of horizontal cells with respect to the photoreceptor input. A microelectrode is inserted into the L‐type horizontal cells of carp and, by stimulating various portions of the retina by a small light spot, the response potential of L‐type horizontal cells is measured. As a result, the amplitude of the response potential exhibits a decay depending only on the distance between the horizontal cell and the point of stimulus, without any directivity in the propagation of potential. In other words, it is shown that the receptor field of the L‐type horizontal cells is spatially uniform with respect to the propagation of potential. On the other hand, when the input from the photoreceptor, is increased by increasing the light spot intensity or by using a wavelength of higher sensitivity, the spatial decay of the response potential of L‐type horizontal cells decreases. This result seems to indicate that L‐type horizontal cells have a saturating nonlinearity in regard to the input from the photoreceptor. The response characteristics of the horizontal cells in this paper are essential in the analysis of color information processing or picture information processing in the retina.
Idle signal multiple‐access (ISMA) scheme for terrestrial packet radio networks
Authors: Mukumoto Kaiji , Fukuda Akira 
Published: July 2007

AbstractThis report proposes a new random‐access packet communication system which is appropriately applied to terrestrial radio and called the idle signal multiple‐access (ISMA) scheme. The characteristics of the system and its realization are studied. In this field, the CSMA system has received particular attention as a system with large channel capacity which can substitute for the ALOHA system. However, an assumption for this system is that all terminal pairs can observe each other's transmitted signals, thus imposing a severe requirement on a centralized system, which does not take into account direct communication between terminals. To cope with this problem, the BTMA system was proposed, but the ISMA system proposed herein shows its superiority to the BTMA system (a frequency‐division method) in such aspects as channel capacity and structural simplicity because the entire frequency band can be used owing to the application of time division to the transmitted control signals. The channel capacity of the ISMA system is generally close to that of the CSMA system and it can be applied to a system operating with dynamic time division of channels for calls in both directions, upward and downward.
Conditions for invariant polarization in a single‐mode optical fiber in pulse wave transmission
Authors: Kusano Kiyonobu , Nishida Shigeo 
Published: July 2007

AbstractConditions are determined for maintaining polarization when pulse waves propagate in a single‐mode fiber in which both non‐uniformity in distribution of the core dielectric constant and cross sectional deformation exist. The coupling coefficient between the waves with left‐ and right‐handed circular polarizations is denoted by β( = β1 − β2). Deformation of the core cross section from a perfect circle and deviation from uniform dielectric distribution can always be expanded into circumferential Fourier series. The values of β1 and β2 are determined by the second‐order Fourier coefficients. The condition of invariant polarization in the fiber is β1 = β2 = 0. The condition for time‐invariance of the plane of polarization is frequency independency of β1 and β2. We also study the effect of twisting of fibers satisfying these condtions. Denoting the rigidity by G, the optoacoustic constant by C and the index of refraction by N, we show that if G·C/N is frequency‐independent, the degree of polarization is maintained in the fiber with invariant polarization although the plane of polarization rotates. When a fiber time‐invariant polarization plane time is twisted, the characteristics remain unchanged. We show several examples of core cross‐sectional shapes and dielectric distributions needed for maintaining the polarization.
Resolution improvement in an analog‐to‐digital converter by the superposed dither signal
Authors: Shimizu Hiroshi , Iikura Yoshikazu , Sasano Yasuhiro , Takeuchi Nobuo 
Published: July 2007

AbstractThis paper discusses a method to improve the resolution of an analog‐to‐digital (A‐D) converter to detect differences less than 1 LSB (least significant bit) in the input signal. Resolution is improved by superposing dither on the input signal and averaging over many measurements. The theory and experimental verification for this method are described.This analysis calculates numerically the expectation value of the result of A‐D conversion and the expectation value of the variance, with the dither superposed on the input signal. The results show that for larger amplitude of dither, the expectation value of A‐D conversion comes closer to the real value, and the expectation value of the variance becomes larger.The relation between the amplitude of dither and the improvement of resolution is calculated as a function of the number of measurements. For example, when the number of measurements is 100 and the amplitude of dither is 0.4 LSB, the resolution can be improved to 0.05 LSB.This analysis is verified experimentally by using a white noise generator as a dither source, dc voltage standard as a signal source, and a transient recorder as an A‐D converter.
Synthesis of sliding discrete fourier transform and sliding hadamard transform circuits
Authors: Fujii Tetsurou , Harashima Hiroshi , Miyakawa Hiroshi 
Published: July 2007

AbstractThe sliding DFT algorithm is a technique for determining the DFT coefficients for time‐series samples. The conventional sliding DFT circuit used in the frequency‐sampling filter, however, is recursive and has an instability problem because of the accumulation of errors in the feedback path. A new sliding DFT circuit is proposed which is also of recursive type but does not accumulate errors. Its behavior is analyzed in detail. The circuit proposed is relatively simple and can easily be translated into hardware. It is also shown that a sliding Hadamard transform circuit is easily constructed, and the design of a sequence sampling filter is shown.