bluuebunny/crossref_metadata_2025_split huggingface dataset:
Centralized data collection systems via meteor burst
Authors: Mukumoto Kaiji , Nagashima Noriaki , Fukuda Akira 
Published: July 2007

AbstractIonized trails caused by the entry of meteors into the atmosphere provide probabilistic communication paths between two points over the horizon. Three protocols for a data collection system via meteor burst communication channels are studied and evaluated. the first is merely the pure ALOHA protocol applied to the probabilistic channel. the second is called the IT protocol. It has a frequency division idle‐tone channel. A terminal which has a message observes this channel and determines whether the main channel is open or closed for it. the third protocol, the so‐called ITT protocol, also has idle‐tone channel. Messages are divided into many blocks (this message structure is called “Tokage (lizard)” type) and go‐back‐N ARQ protocol is utilized. We show that the idle‐tone and the lizard‐type message with ARQ, are extremely effective to increase the channel utilization in such systems. It is also shown that high channel utilization can be achieved by the use of the ITT scheme even in a probabilistically generated and terminated communication channel such as meteor burst communication path.
Axis misalignment and splice loss estimation of single‐mode optical fiber splicing using core direct monitoring
Authors: Kawata Osamu , Hoshino Koichi , Miyajima Yoshiaki , Ohnishi Masatoshi , Ishihara Koushi 
Published: July 2007

AbstractThis paper examines the splicing loss due to axis misalignment in the splicing of single‐mode optical fibers using direct core monitoring and discusses the methods for reducing such loss and the techniques for estimating it. Axis misalignment is strongly dependent on the offset between the monitoring location and the actual position due to the fiber lens effect and core eccentricity as well as on the precision of the core monitoring system. Taking into consideration the indeterminateness of the relative position of the fibers, we analyze this relationship by means of a statistical technique and, using a direct core monitoring system with transmitted light, verify the appropriateness of the theory by means of experimental studies. Further, it is shown that it is necessary to reduce the alignment error due to core eccentricity and that it is possible to align the cores to a precision of better than 0.5 μm by correcting the core center position from the observed eccentricity. In addition, by considering the surface tension effects during fusion we can explain the relationship to axis shift before and after splicing and, if the axis alignment precision is given prior to splicing, we can estimate the splicing loss distribution. We also show that it is theoretically possible to achieve an average splicing loss of less than 0.1 dB with single‐mode fibers using this direct core monitoring method when the axes are aligned to within 0.5 μm.
Quasi‐optical diplexer by rectangular metallic mesh
Authors: Sato Ikuro , Tamagawa Susumu , Iwata Ryuichi 
Published: July 2007

AbstractThis paper provides the results of theoretical and experimental studies to realize a broadband quasi‐optical diplexer with polarization‐independent characteristics, using multilayer rectangular metal meshes. A rectangular metal mesh is usually used in the inductive region below the mesh resonant frequency. In the theoretical analysis based on the mode matching method, it is concluded that the anomalous resonance of the mesh appearing below mesh resonant frequency in TM oblique incidence is caused by the higher‐order modes generated on the metal mesh surface. This phenomenon can not be explained by the equivalent circuit analysis, in which metal mesh is decomposed to two orthogonal metal strip gratings. A bricktype rectangular metal mesh is proposed in which the anomalous resonance can be eliminated from the operating frequency region. It is shown theoretically and experimentally that one can realize a new metal mesh of which the transmission characteristics below the mesh resonance do not vary in accordance with the incident polarization mode. A design method of quasi‐optical diplexer using this brick‐type metal mesh is described and the experimental results of the filter designed for diplexing the six, 4 GHz and fourteen, 11 GHz signals are reported. It is confirmed that broadband diplexing is possible with a stacked rectangular metal mesh and that the design method is legitimate.
High‐precision automatic ellipsometer and whereby evaluation of a very thin silicon‐oxide layer
Authors: Iwamura Soichi , Nishida Yasuaki 
Published: July 2007

AbstractTo measure automatically both the thickness and the refraction of films of several tens of angstroms, e.g., a barrier oxide for MNOS memory with high precision, a high‐speed automatic ellipsometer has been developed which can measure accurately the extinction positions of polarizer and analyzer. Hence, the polarizer/analyzer extinction positioning accuracy of 1 × 10−4 degrees has been obtained in the repeatability test during the same sample measurements. By aligning and calibrating many optical components, a perfect extinction has been obtained in crossed Nicols with a quarterwave plate (PCA). For the position detection, the optical encoder scales drawn by electron beam exposure system are read by a laser beam detector, resulting in positioning accuracy of 10−4 degrees. Next, an example is shown where the thickness of a native oxide formed on a silicon wafer is measured by this system. the possibility is shown of evaluating the oxide surface roughness with the standard deviation around the average thickness from the polarizer/analyzer extinction curve, the measured extinction factor, and the deduced value from the oxide model.
Three‐level optimization algorithm for nonconvex problems with block angular structures
Authors: Sakawa Masatoshi , Member Regular 
Published: July 2007

AbstractA three‐level optimization algorithm is proposed for a large‐scale nonlinear programming problem with nonconvexity and block angular structures based upon the general duality theorem. In the three‐level optimization algorithm the augmented Lagrangian function as well as the auxiliary variables of the second term in the augmented Lagrangian function are introduced to resolve the so‐called duality gap and conversion is done to obtain an additively separable form. Then, an independent partial problem is solved and the dual function is determined by using the sum of the object functions in the partial problem. Further, an example of application with simple numerical data and nonconvexity is shown to confirm appropriateness of the proposed three‐level optimization algorithm.
Simulation of a noise source with a 1/f spectrum by means of an RC circuit
Authors: Motoishi Kohji , Koga Tosiro 
Published: July 2007

AbstractThe fact that a power spectrum is inversely proportional to frequency is of interest in the fields of engineering, physics, and physiology. This paper presents a theoretical design method for a network whose power spectrum response to noise is a good approximation to the so‐called 1/f‐response in a given frequency band between lower and upper limiting frequencies. The network is a filter whose transfer function to white noise is 1/√s. The input impedance of a cascade connection of semi‐elementary sections composed of symmetrical RC lattices whose image impedances are 1/√s is a close approximation to 1/√s. Design formulas and diagrams of the approximating function, showing the relationships between the parameters of the frequency band, the approximation and the degree of the approximating function are given. A filter whose transfer function is an approximating function is realized by a cascade of symmetrical RC lattices and an operational amplifier. An experimental test of a tenth degree filter shows good characteristics in the frequency band 1 Hz ‐ 100 kHz. It is shown that the approximating function is applicable in the design of a Wiener filter for the reduction of 1/f fluctuations.
Speech synthesis using generalized cepstrum
Authors: Kobayashi Takao , Imai Satoshi 
Published: July 2007

AbstractAs a speech analysis method using the generalized cepstrum there is a method based on a generalized logarithmic function instead of a logarithmic function as an evaluation scale. This paper presents a speech synthesis system using the generalized cepstrum, which is defined as the Fourier coefficients of the generalized logarithmic spectrum. The direct approximated digital filter using the Padé approximation, which is the inverse function of the generalized logarithmic function, is used as a synthesis filter. Since this filter not only gives a good approximation of the desired generalized logarithmic spectrum by a generalized cepstrum but also since the values of generalized cepstra correspond to the filter coefficients as they are, it is easy to determine the synthesis filter coefficients. Since the synthesis system in this paper is fully compatible with the one based on the conventional cepstrum method, it is possible to synthesize speech by the generalized cepstrum without changing the speech synthesis system based on the conventional cepstrum method. Also, using this synthesis system, it is possible to synthesize speech by the conventional cepstrum method as a special case of this method. With proper choice of the parameters of the generalized logarithmic function, the synthesized speech by this method is of higher quality than that by the conventional cepstrum method.
An analysis of pulse response with phase delay in transistor circuits by means of state variable approach
Authors: Ishibashi Shinichiro , Member Regular 
Published: July 2007

AbstractThe fact that the pulse response of a transistor circuit is accompanied by a phase delay is well known. The quantity β(s), which plays the role of the frequency response of α(s), is expressed in terms of polynomials and the transformation formulas are obtained by introducing a state variable into β(s). After α(s) is set equal to d0e−sm/ωa, this transformation gives a response that agrees satisfactorily with measurement. This is true even when the measured pulse response has a phase delay from the start of response to the steady state conditions. This paper also gives the phase delay element value. When the delay time contained in the element is compared to m/ωα obtained from the response, the delay time of the pulse response can be directly determined within the phase interval from 45° to 90°. In addition, the relationship between the location of centroid of the impulse response coordinate axis and the 50% rise time of the indicial response and the carrier transit time is also investigated.
A new reliability evaluation method based on using the parasitic MOS formation phenomenon
Authors: Kumura Masao , Fujita Kazuya , Hayakawa Masao , Aoki Yoshimasa 
Published: July 2007

AbstractOne of the instabilities in plastic‐encapsulated MOS LSI is due to leakage caused by parasitic MOS formation. This paper uses this parasitic MOS leakage phenomenon to evaluate the surface reliability of new MOS. In this investigation the center of the gate electrode is omitted, and an MOS transistor with a partial gate structure is fabricated; plastic encapsulations are used, and the source‐drain leakage current variation with time is investigated with a voltage applied between source and drain. The results are shown to be different with different plastic encapsulation. The maximum leakage current increase rate is denoted by α. The parameter α is temperature‐dependent and a linear relationship exists between the logarithm of α and the reciprocal of the absolute temperature T. The activation energy is found to be 1.1∼1.4 eV. The theoretical formula of the physical meaning of α shows that α is proportional to the diffusion constant of the parasitic MOS formation, and the correctness of the new evaluation method using α is confirmed. Our method has good repeatability. In addition, it permits an easier and, because of high sensitivity, a faster evaluation than the conventional method using variations of the threshold voltage VT.
An optical guided‐wave dye laser and directional coupling amplifier
Authors: Hamano Osamu , Sasaki Keisuke 
Published: July 2007

AbstractThe properties of a new type active thin‐film optical waveguide with layers of Corning glass 7059, Pyrex, and Rh 6 G dye formed on a fused quartz substrate are discussed. It generates superradiant emission when excited by a pulsed N2UV laser. When the top layer is shaped as a square, resonant behavior is observed between the corner reflectors formed by the edges on the diagonal. When the optical path is displaced normal to the diagonal, a distinct resonance is observed. This structure was used as a directional coupler and the coupling efficiency was found to depend on the waveguide length. These properties can be treated theoretically relatively simply in terms of a complex propagation constant with a positive imaginary part.
Performance analysis of some ARQ protocols
Authors: Iisaku Syun‐Ichi , Hatori Kozo 
Published: July 2007

AbstractARQ (Automatic Repeat Request) schemes are methods for controlling the error in data transmission. Among the schemes previously proposed are the selective repeat, the GO‐BACK‐N, and the combinations as well as the modifications of these schemes. The analysis of these schemes has been performed on the basis of a simplified model. This paper presents the analysis of several ARQ schemes using a more complex model which takes into account the long propagation delay (such as satellite links), transmission delay associated with retransmission, the system internal time, and the buffer size of the sending station. A concept of equivalent channel holding time is used in conjunction with a M/G/1 queueing model for the analysis of the system throughput as well as other characteristics.
Optical time domain reflectometer for backscattered light
Authors: Nakahira Mizuho , Tokuda Masamitsu , Omote Koji , Kosugi Takayuki , Kitagawa Kazumaro 
Published: July 2007

AbstractIt is possible to detect the point of breakdown and to obtain the loss of optical fibers by measuring the backscattered light caused by Rayleigh scattering. This paper describes design and test results for a small, light‐weight, high‐performance optical time‐domain reflectometer. To obtain masking functions for excessive pulses such as those obtained by Fresnel reflection, we use an image dissector as the detector and obtain a 50‐dB masking attenuation. A digital averager is used to improve the S/N ratio. The time required for 1000 averagings is only 40 seconds. To prevent drift, an AC coupled amplifier and a zero‐level sampling system are used and sufficient temperature stability is realized. The experimental reflectometer is able to detect the breakdown point as far away as 8 km with backscattered light and at 14 km with perfect end Fresnel reflection. The error in the loss measurement is less than 0.05 dB for the distances up to 4 km. From these results, the tested reflectometer is found usable in practice.
Evaluation of large scale T‐S‐T types of networks controlled by homing‐type path hunting strategies
Authors: Ogino Nagao , Saito Tadao , Inose Hiroshi 
Published: July 2007

AbstractOne of the important problems in the design of switching systems is to arrive at a switching network with high efficiency. In order to obtain a switching network satisfying economical requirement for the total switching system including the processing devices, the system must be evaluated from the viewpoint of the amount of processing in path‐hunting, as well as traffic efficiency and hardware cost. From such a viewpoint, the authors conducted evaluations based largely on simulation of the path‐hunting processing in the switching network. However, since simulation involves practical difficulties in the evaluation of a large‐scale switching network, a simple and theoretical method is desired to evaluate the amount of processing in path‐hunting. This paper presents a theoretical method of evaluation for the homing‐type path‐hunting system, which is superior from the viewpoint of blocking probability and the amount of processing. The effectiveness of the proposed method is demonstrated. Using the proposed method, the relation between the path‐hunting scheme and the blocking probability is derived and actual large‐scale T‐S‐T switching networks are evaluated from the viewpoint of the amount of processing in path‐hunting. The result of evaluation indicates that a switching network with higher traffic efficiency tends to require a larger amount of processing in a large‐scale switching network as well. The optimum switching network type is indicated, considering the amount of processing in path‐hunting.
Some comments on the analysis of electromagnetic fields in inhomogeneous media
Authors: Yamaguchi Shoji , Hosono Toshio 
Published: July 2007

AbstractAmong the principal approaches to electromagnetic field analysis in an homogeneous medium are numerical methods. The homogeneous multilayer approximation used in numerical methods is invalid when there is wave equation singularity. This paper demonstrates that the finite difference method is equivalent to the homogeneous multilayer approximation methods when the number of subdivision is increased; further, it is shown that finite difference methods also can be invalid. To analyze electromagnetic fields in the medium for which the wave equation contains a singularity, we propose here an inhomogeneous multilayer approximation method (a piecewise linear approximation) based on the power series solutions. A technique is presented for improving the homogeneous multilayer approximation method and the finite difference method by using the results of piecewise linear approximations. We further propose a modified multilayer approximation method by combining advantages of various methods. The principal features of the modified multilayer approximation method are as follows: 1) Calculations are possible even when the wave equation has several singularities; 2) the method is applicable to the structure with arbitrary medium profile; 3) the solution near the singularities can be obtained relatively easily; 4) a desired degree of accuracy can be obtained by increasing the number of subsections; and 5) no extensive mathematical background is required.The modified multilayer approximation method is used to analyze the reflection of a plane wave from an inhomogeneous plasma slab. Presented in graphical manner are the power reflection coefficient, the energy absorption, the electromagnetic field distribution inside the slab and the power flow.
Grating diplexer using dielectric waveguides for millimeter wavelengths
Authors: Shinonaga Hideyuki , Kurazono Sadao 
Published: July 2007

AbstractA new grating diplexer using dielectric waveguides is proposed for millimeter‐wave applications. It consists of two symmetric rectangular dielectric waveguides in which two 3‐dB hybrids and two gratings for band‐stop filters are contained. Hence, it is convenient for integration. In the analysis of grating structures, we introduce equivalent circuits to which F, S, and T matrices are applied to obtain the dispersion properties and the frequency characteristics of reflection and transmission. Experimental data obtained at millimeter‐wave frequencies agree well with theoretical values. It is found that millimeter‐wave grating diplexers can be used as bandsplitting diplexers and channel diplexers in millimeter‐wave communication equipment.
Network control system using traffic database in public telephone network
Authors: Mase Kenichi , Kajiwara Masaichi , Yamamoto Hisao , Shinohara Masaaki 
Published: July 2007

AbstractA traffic ontrol system using geographically distributed traffic databases is proposed. Each data base maintains nationwide network information such as the busy/idle statuses of customer lines and trunk groups.A local switching system accesses the regional database to process each outgoing call adequately. Each database periodically obtains local network information from all switching systems within the region of its coverage, transferring it to other data bases. Used in this system are, for example, satellite broadcast channels which update simultaneously the information stored in the data bases.For this traffic control system, (1) an acceptable time delay required to update the databases and to set up calls is obtained; (2) the effectiveness of this control system for dealing with focused overload is evaluated; and (3) loads on signaling channels, the satellite channel and the database system also are evaluated.
Characteristics of signal error and signal‐to‐noise ratio in γ‐Fe2O3 thin film disks
Authors: Ishii Yoshikazu , Terada Akira , Ishii Osamu , Ohta Satoshi , Nakagawa Takehiko 
Published: July 2007

AbstractSignal errors and signal‐to‐noise ratios of reaction‐sputtered γ‐Fe2O3 high‐speed magnetic disks (diameter 210 mm) have been investigated with a memory density of 620–640 bit/mm and a core width of 15 ‐ 16 um. The results are summarized: (1) Errors have been reduced by removing substrate surface and exfoliation defects of the sputtered magnetic film. (2) Errors on a single surface are reduced to less than 10 with a high purity substrate having a small number of impurity segregations. (3) Exfoliation errors have been completely removed by adopting triple sputtering. (4) Investigation of the results obtained with various sputtering processes and sputtering conditions shows that the signal‐to‐noise ratio is closely related to the crystal grain size of the γ‐Fe2O3 magnetic film. (5) Addition of Cu is found to be effective in suppressing crystal grain growth, and can improve the signal‐to‐noise ratio.
High‐rate, low‐temperature sputtering method of facing‐targets type and its application for deposition of magnetic films
Authors: Hoshi Youichi , Naoe Masahiko , Yamanaka Shun'Ichi 
Published: July 2007

AbstractTo realize high‐rate, low‐temperature sputtering, two parallel targets were used and a magnetic field was applied perpendicular to them. The γ‐electrons emitted by the targets contribute to formulation of a high‐density plasma between the targets and to controlling the γ‐electrons striking the substrates. As a result, the authors were successful in depositing such magnetic materials as iron and nickel on a substrate without heating at 50 times the rate in ordinary diode sputtering. This method also prevents high‐energy ions from hitting the substrate and permits deposition of a film of large area with uniform thickness. The observed profile of the film thickness agreed with the calculated one in which the cosine law of sputtering was assumed. A practical model of the present sputtering apparatus was fabricated with permanent magnets and its performance was investigated.
An algorithm for generating circuit diagrams of LSIs
Authors: Nishiguchi Nobuyuki , Kawanishi Hiroshi , Nakao Masumi , Kishimoto Aritoyo 
Published: July 2007

AbstractThe degree of IC integration has shown yearly increases. Hence, the amount of layout data also has increased. Therefore it is very important to verify that a given circuit is realized correctly on a layout. To simplify verification we reconstruct the diagram of a given circuit from its layout data. We present an algorithm for reconstruction and describe a system which incorporates it. The circuit diagrams reconstructed by this algorithm resemble these drawn by layout designers. Hence it is a very effective means of layout verification. In this algorithm we use a graph to show the interconnections of transistors given by layout data. We group transistors into a number of subgroups so that each group forms a logical unit. Then we determine the positions of the transistors within each group and the positions of the logical units. Finally we reconstruct a circuit diagram resembling the hand drawn one by determining the final positions of the transistors of the circuit based on those positions.