bluuebunny/crossref_metadata_2025_split huggingface dataset:
A composite sinusoidal model applied to spectral analysis of speech
Authors: Sagayama Shigeki , Itakura Fumitada 
Published: July 2007

AbstractA new technique of speech analysis based on a composite sinusoidal model is proposed. In this model, parameters (frequency and intensity of each sinusoid) are determined such that the lower‐order autocorrelation functions of the finite number for the reference signal (a sum of several sinusoidal waves) is equal to those for the observed speech signal. The model is classified into four types: (1) the frequencies of the sinusoids are free; (2) one frequency is fixed to 0; (3) one frequency is fixed to π; and (4) two frequencies are fixed to 0 and π. For all of these, the parameters are solved easily by the basic algebraic method. While the problem is essentially related to the theory of orthogonal polynomials, it is proven that the roots exist if only the autocorrelation function is a positive definite matrix. The efficient algorithm is introduced. Itakura's theory of line spectral representation of linear predictive coefficients can be considered as the conversion theory from the LPC to the composite sinusoidal model. Some experiments of speech analysis are demonstrated. Applications to the speech analysis and synthesis, synthesis by rule, speech recognition, speaker identification, etc., are suggested.
Chromatic spatial frequency response of the human vision—chromatic axes with spatial frequency bandwidth at colored point
Authors: Sakata Haruo 
Published: July 2007

AbstractA chromatic spatial sinusoidal pattern composed of a complementary color‐pair is displayed on a color‐monitor screen, and, on adding color (saturated Y, M, C and B) to the screen, the color‐difference discrimination threshold for the colored chromatic sinusoidal pattern is determined at low frequency (0.36 cpd) and high‐frequency (3.6 cpd). The direction of the complementary color‐pair, along which the high‐frequency sensitivity decreases most at each color, passes through a point on the u‐axis of the CIE u v chromaticity diagram and almost coincides with the color‐confusion locus of the third color‐abnormal case. On the other hand, the direction of the complimentary color‐pair along which the high‐frequency sensitivity decreases least is almost parallel to the U‐axis. These results indicate that the spatial frequency characteristic of the chromatic channel can be considered to be independent of the average chrominance.
Propagation paths of cyclotron harmonic waves with curvature of geomagnetic field taken into account
Authors: Utsunomiya Toshio 
Published: July 2007

AbstractThe propagation path of cyclotron harmonic waves in the ionosphere and magnetosphere was derived by J. Bitoun. However, the propagation path at low altitude has not yet been investigated. This has been due to the complexity in the analysis in which the curvature of the earth's magnetic field must be considered. In this paper, the propagation path is expressed in a simple equation which considers the curvature of the earth's magnetic field. With this expression, the traveling distance varies depending on the magnetic latitude and altitude of the location of the wave exciter. With the assumed electron density distribution, the corresponding regions in the ionosphere and magnetosphere are clarified. Then the propagation path is calculated with two representative points in these regions. When kX0 > 0, the traveling distance becomes maximum after the reflection point. When kX0 < 0, the effect of the curvature is large, causing a large variation in the traveling distance.
An erasing method of hard magnetic recording media
Authors: Matsumoto Mitsunori , Morisako Akimitsu 
Published: July 2007

AbstractA two‐step erasing method (dc and ac erasures) is proposed for hard magnetic recording media and test results obtained using experimental erasing heads are presented. The ac erasing characteristics of the commercially available voice‐recording magnetic tapes are measured. The metal tape with 1.06 kOe coercive force requires 2.1 kOe erasing field to obtain 60 dB erasing rate. In the two‐step erasing method, only a 1.2–1.3 kOe field is needed to obtain 60 dB erasing rate for the metal tape when the tape is dc‐erased up to 30 dB. An experimental dc erasing head (permalloy head with 0.08–0.36 mm air gap, 900–3000 windings and 0.81–2.1 mm core width) is fabricated and its dc erasing characteristics are examined. The erasing state is observed by the Bitter method. The gap length of the erasing head must be 1/4 ‐ 1/5.6 of the recording tack width. The effectiveness of the two‐step erasing method is confirmed experimentally.
Nonvolatile memory effects of chalcogenide amorphous semiconductor doped with AG
Authors: Hirose Yooichi , Hirose Haruo , Kunioka Akio 
Published: July 2007

AbstractWith Ag‐photodoped amorphous As2S3 specimens that have nonvolatile memory effect, the electric conduction, temperature and frequency characteristics and thermoelectromotive force are investigated. The fabrication yield of this specimen is almost 100%. This device has a switching function, and the off‐state has a semiconductor type electric conduction with energy gap of 2 eV. The on‐state has metallic conduction and its temperature coefficient is almost the same as that of Ag, 4.0 × 10−3/°C. With a lateral‐type specimen (Au‐Ag electrodes), Ag dendrites are observed under a microscope. The dendrites bridge the two electrodes, resulting in memory action. The bridging of an Ag dendrite played the same role as a crystalline‐amorphous phase change in ordinary semiconductor memory operation.
A new sampling theorem based on the minimum energy principle
Authors: Kishi Genya , Sakaniwa Kohichi 
Published: July 2007

AbstractAmong those low‐pass band‐limited waveforms which take specified sampled values at a specified finite number of sampling points, the one with minimum energy is called the minimum‐energy waveform. This paper first derives the minimum‐energy waveform and strictly proves its uniqueness. Discussion is then devoted to the minimum‐energy waveform which is determined by sampled values of a low‐pass band‐limited waveform of finite energy, and it is shown that the sequence obtained by successively adding sampling points uniformly converges to a low‐pass band‐limited waveform. In general, when a low‐pass band‐limited waveform is uniquely determined from the sampled values at the sampling points, the sampling point sequence is called complete. This paper shows that various kinds of sampling theorems can be derived, by prescribing sampled values for the low‐pass band‐limited waveform for the complete sampling point sequence given by Levinson and constructing the limiting waveform of minimum energy. Especially, a new reconstruction formula is obtained which restores the original band‐limited waveform solely from the past sampled values. It is shown that the traditional Someya‐Shannon interpolation formula can be obtained by specifying particular sampling points in the above restoration formula. The relation between the two formulas is also discussed.
Probability distributions for ratios of fading signal envelopes and their generalization
Authors: Okui Shigehiko 
Published: July 2007

AbstractThis paper describes statistical characteristics of the ratios of fading signal envelopes. The Rayleigh fading is contained as a special case. We derive the ratios of the fading signals following the m distribution, generalized Nakagami‐Rice distribution and generalized Nakagami‐Hoyt distribution. An extension to the case of multiple variable distribution is attempted under some conditions. The results in this paper are given in simple functional forms appropriate for theoretical analysis. The distributions of the ratios of fading signal envelopes can be applied to a wide range of problems of radio wave interference such as evaluation of the ratio of desired signal to unwanted interference signal (DU ratio) and of degradation of cross‐polarization discrimination (XPD) in a microwave transmission channel, determination of frequency reuse distance and of modulation types for mobile communications, and analysis of ratio detection in radar technology.
Generation of defects at Si‐SiO2 interface in electron beam lithography
Authors: Sugano Takuo , Yeh Ching‐Fa 
Published: July 2007

AbstractIt is found that the Si‐SiO2 interface‐state density generated by 25‐keV electron beam lithography does not depend on thickness of the resist. With delineation by a 2‐keV electron beam, interface states are mainly generated by the characteristic × rays, Kα of an Al electrode which the beam strikes. These trapping centers are holes trapped in the interface and they remain when the specimen is annealed in an inert gas at 800°C. However, after annealing in a hydrogen gas at 400°C for 30 min they disappear, but when annealed further in a neutral gas at a higher temperature they reappear. On the other hand, interface states which disappear by annealing in a carbon tetrachloride gas at 800°C for 1 hour, never reappear by annealing at 1000°C in the same atmosphere.
Approximation and construction of the network containing variable elements
Authors: Kawakami Atsushi , Takahashi Shin‐Ichi , Tajima Jun 
Published: July 2007

AbstractA variable network is a network in which a designated input‐output characteristic can be obtained continuously by varying continuously a specific parameter. This paper describes two methods of approximating the desired variable characteristics by a rational transfer function and constructing it as a concrete network. In the conventional method, an approximation with good accuracy is obtained by raising the orders of the complex frequency s and the variable parameter λ. The actual construction of the network becomes difficult because of the higher orders. Two methods are proposed in this paper to avoid this difficulty. In the first method, the approximated transfer function is divided into unit blocks, lower order for the complex frequency s and a bilinear form for the variable parameter λ. By this method, the actual construction of a network can be simplified considerably. In the second method, the desired characteristics are approximated in the form of a transfer function in which the denominator polynomial is resolved into the polynomials of s and λ, respectively. The approximated transfer function in this form has a merit in that it can be realized with a minimal number of dynamic elements and variable elements in the network construction. Moreover, its stability is independent of λ.
A theory of a nonuniform transmission line and the structure of signal flow
Authors: Ito Chiaki , Sato Risaburo 
Published: July 2007

AbstractThis paper deals principally with the phenomenological description and structural analysis of the signal flow of a nonuniform transmission line and presents a theoretical discussion, including the traditional theories, of the uniform transmission line. Due to the existence of local multiple reflections caused by nonuniformity, the phenomena on the nonuniform transmission line cannot be as clearly described as in the case of the uniform transmission line. The reason for existence of the local multiple reflections, however, is the lack of appropriate selection of the incident and reflected waves from the solutions of the transmission line equation. From such a viewpoint, this paper newly defines the incident and reflected waves as waves obtained by exciting a semiinfinite transmission line in the positive or negative direction. According to this definition, the two waves are not coupled and do not produce the local multiple reflections due to the nonuniformity. Thus, using such incident and reflected waves, a unified analysis can be made for the transmission line, independently of whether it is uniform or nonuniform. At the same time, the signal‐flow structure for such phenomena as reflection, matching and resonance can clearly be described. Using the concept of signal flow, the ultimate expressions for various quantities can easily be reached.
Considerations on diameter of communication networks
Authors: Kurosawa Kaoru , Tsujii Shigeo 
Published: July 2007

AbstractThis paper discusses the relation between the diameter and the number of nodes of a regular graph; also discussed is the relation between a regular graph with minimum diameter and minimal d‐connectivity from the viewpoint of graph theory for the construction of a communication network with high reliability and quality of communication.First, it is shown that the upper bound of the number of nodes n for given diameter k is Nk−2 in almost all cases, where Nk is Moore's upper bound. Second, it is derived that a regular graph with diameter k and degree d is minimal d‐connected when k ≧ 3 and Nk−d ≦ n < NK or k = 2 and n = N2−2.
DPCM variable length coding system for image using bifix‐free pattern
Authors: Saito Tadao , Inose Hiroshi , Yanaka Kazuhisa 
Published: July 2007

AbstractIn the past, variable length DPCM coding of gray scale image utilized block coding such as Hoffman coding scheme. However, if the midriser quantizer is used, the two levels close to zero level will occur with high probability. In such a case, the Huffman coding without extending the information source still results in a considerable level of redundancy. This is because the codewords can exist only at the tips of the branches of the coding‐tree, which is the constraint for the instantaneously decodable block code. This paper proposes a coding scheme which applies a technique similar to that used for transparency acquisition in the HDLC scheme, to insert a dummy bit into the non‐blocked codewords. In principle, it uses the properties of the bifix‐free pattern. When the two quantized levels close to zero occur with high probability, the proposed coding scheme yields a higher compression factor than does the Huffman code. Furthermore, the coding parameters can be varied adaptively depending on the properties of the image. Both the theoretical aspect of the proposed scheme and the simulation based on the standard test images are discussed in this paper.
Display methods of laser radar data using a computer system
Authors: Shimizu Hiroshi , Sasano Yasuhiro , Yasuoka Yoshihumi , Matsudo Osamu , Takeuchi Nobuo , Okuda Michio 
Published: July 2007

AbstractIn the computerized laser radar data processing, it is important to utilize effective data‐display techniques. This paper examines two‐dimensional data display methods using the computer peripheral systems. Five methods (color level slicing, grey level slicing, dot density, contour and perspective methods) are selected and their advantages and disadvantages are examined. According to the quantitative examination on the output efficiency, the number of data per one display, etc., the density method is the best among all methods.
Realization of open‐input type second‐order active RC filters using two operational amplifiers
Authors: Arai Ikuo , Suzuki Tsutomu 
Published: July 2007

AbstractOne of the active RC circuit realization methods is the inductance simulation method. Conventionally, the modeling of the floating inductance is aimed at the bi‐directional inductance L. In this paper, the authors consider the case where realization of the “unilateral” inductance is simpler than the bidirectional inductance and perform the realization using two operational amplifiers. It is shown also that the unilateral FDNR can be realized by the same procedures. These unilateral L and FDNR are applied in the realization of the open‐input type (∞‐0 type) second‐order filters which are new circuit types. Moreover, it is shown that the ∞‐0 type second‐order filters can also be derived from the ∞‐0 type for the realization of the open‐input/voltage source‐output circuits. In either circuit type, all the second‐order transfer functions are realized in the ∞‐0 type filters by using the L and FDNR circuits. The second‐order filter groups proposed in this paper have advantages in that the number of elements is less and the sensitivity is lower than in the ∞‐0 type filters. As an experimental example, the measured and calculated values are shown for the frequency characteristics of the ∞‐0 type second‐order low‐pass filters. Their operations are then verified.
A periodically sampled queuing system with load regulation
Authors: Yoshida Makoto 
Published: July 2007

AbstractIn connection with the periodical registration processing systems, which is uniquely applied to real‐time processing systems, analysis and evaluation are conducted for a system that has load regulation by restricting registration to finite central processor buffers and CP systems. Under the conditions of a single processor, a constant period T, Poisson arrival calls and holding times (average value h) with negative exponential distribution, the author formulates the population function representation of calls in systems immediately after a certain period, and, based on this, calculates the overflow rate and the maximum traffic to be carried per period. Next, using the above distribution, the average number of waiting calls in the CP buffers and outside the CP system at any time are formulated and the average waiting time is calculated by using Little's formula. The continuity of various characteristics in the above nonsaturated state are then examined based on analysis of the saturation states where there always exist waiting calls in the queue outside the CP system. Finally, numerical computations show that as certain evaluation measures such as the number of CP buffers n vary and saturate at about n = 30 if T/h < 30, then at n greater than T/h, T/h < 30. From the above it can be concluded that load regulation has some effect without decreasing the maximum traffic a0 on the conditions that as many CP buffers as economically possible are installed and the period T (T/h) is kept large enough within the allowable range of the average waiting time.
Characteristics of the dominant mode in a dielectric tape line
Authors: Wakabayashi Toshio , Mihara Yoshio 
Published: July 2007

AbstractA dielectric tape line consists of a dielectric material of rectangular or semi‐elliptical cross section having a small thickness‐to‐width ratio and placed on a conducting plane. Analysis is here conducted by using an elliptical coordinate system. Because of the use of new field functions in the interior of the tape line, convergence of the solution of the characteristic equation is much faster than other cases. In this paper, we study theoretically and experimentally the characteristics of the dominant mode. First, the analytical results are outlined. Next, the formula for the attenuation is derived and the attenuation mechanism is explained from numerical examples. The relative strength of the electric field in the horizontal and vertical directions is computed outside the tape and the results are given. We also study the relative intensity distribution of the interior electric field, the ratio of the power carried inside the tape to the total power transmitted, and the spread of the electromagnetic field. Analytical results of the attenuation characteristics and the relative intensity distribution of the external field agree very well with experimental results.
Scattering of a plane electromagnetic wave by a conducting circular cylinder of finite length
Authors: Kinoshita Teruhiro , Sekiguchi Toshio 
Published: July 2007

AbstractThis paper presents an exact solution for scattering of a plane EM move (TM mode) by a perfect conducting circular hollow cylinder having no end caps. The scattered field is evaluated in the Fourier domain using the Wiener‐Hopf technique. The scattered field is divided into the IPO (improved physical optics) field, TE and TM modes in the cylinder and the diffracted fields at two edges. The range of the scattering angle where the IPO field gives good approximation is almost independent of the cylinder length if the cylinder length is larger than several wavelengths.
Traffic analysis of an alternate routing method for store‐and‐forward switching network
Authors: Kawashima Konosuke 
Published: July 2007

AbstractIn a packet switching type of store‐and‐forward switching network, one of the important problems is that of routing. Traffic analysis of networks has hitherto been done mainly by simulation. This paper, however, studies the problem analytically and gives a basic theory for traffic design. When the queue length of the output channel of the 1st‐choice group is full, the arriving call (packet, message, etc.) is routed to the 2nd‐choice group by means of an alternate routing scheme.In the case of a telephone network (instantaneous network), the alternate relay theory has already been established. Based on this theory, a similar queueing system is described here. First, the properties (moment) of overflow calls from a multiple line system having finite waiting room size is gradually determined. Next, the overflow call process is approximated by the interrupted Poisson process and the mean waiting time of an overflow call routed to the 2nd‐choice group is determined. On the other hand, considering both the 1st‐ and 2nd‐choice groups simultaneously, the exact mean waiting time is determined. By comparing the numerical values of the two, it is shown that the interrupted Poisson process approximation of the overflow call process is more or less accurate. Finally, as an application of this approximation, a single‐channel system with finite waiting buffer fed from two sources‐Poisson and interrupted Poisson (overflow traffic)—is analyzed and it is clearly shown that the properties of the overflow call traffic becomes worse than those for the Poisson call traffic.
Simultaneous approximation for two kinds of system characteristics using descent method
Authors: Kiranon Wimat , Machida Toichi , Yoneyama Masao 
Published: July 2007

AbstractThe descent method is applied for simultaneous approximation for system characteristics with two different characteristic requirements. With given initial parameters, the descent directional vectors which derease two performance functions simultaneously are determined from the gradient vector of the performance function of each characteristic and the successive approximation is made from approximated parameters. In the algorithm, both performance functions always decrease at each step under given conditions. Next with newly defined weighting coefficients, both performance functions are decreased simultaneously at a given rate. The convergence limit of this simultaneous approximation is made clear. The effectiveness of the present method and examples of weighting coefficients are discussed.
Adaptive detection of unknown signal in colored noise of unknown parameters
Authors: Miki Shigehiko , Yoshida Kunihiko , Kaneku Seiko 
Published: July 2007

AbstractThis paper describes the adaptive detection of an unknown signal in colored noise. Given the statistical parameters of the observed noise, the Gremlin machine is well known as a learning scheme for the signal pattern. When this scheme is extended to unknown noise parameters, the correlation of observations based on noise poses a problem.Here, additive colored noise is modelled by a self‐recursive process of Gaussian type of past‐dependent width k and the dispersion of its random component is unknown. Its coefficient group is taken as one of the elements of a known finite collection. Further, k does not exceed the observation space width, etc. Based on these premises, first an optimal supervised learning scheme is derived using a Bayesian scheme. Next, the theoretical convergence is studied for this learning scheme and it is shown that, under certain conditions, the detection scheme converges to that for all known parameters. Further, for a special case, the theoretical error probability of a case with assumed estimated noise parameters is computed. The importance of study of correlation between observations is pointed out at the same time the case in which the true values of the noise parameters are not included in the known finite collection is also studied. Thus, the effectiveness of the present learning scheme is clearly shown. Finally, characteristics of the learning scheme are also studied by computer simulation.