bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of characteristics of meander heat elements for a thermal printing head
Authors: Shibata Susumu , Ito Masanobu 
Published: July 2007

AbstractThis paper describes the evaluation of characteristics of meander type heat elements for facsimile thermal printing heads. Mainly rectangular type heat elements have been used for this purpose to date. However, they have some inherent weak points, such as difficulty in obtaining a uniform temperature distribution in a desired heating region and difficulty in obtaining a resistance value suitable for driving them. the authors have manufactured samples of meander type heat elements and investigated them mainly from the point of view of their applicable range and reliability. It is known that (1) in meander type heat elements, if the thickness of the element is greater than a certain value and if the elements are covered with protective layers, the elements withstand heat pulses independently from the thickness of the elements. This also prevents the deterioration of elements due to oxidation. (2) the protective layer on a meander type heat element has greater resistance to thermal shock and better printing characteristic than those of a rectangular type heat element. (3) the meander type heat element does not cause local fusion in the heat insulation layer because of uniform heating. Therefore, this has a higher reliability over a wide range of driving pulse widths. (4) the meander type heat element is inherently superior to the rectangular heat element and will make a greater contribution to improvement of the quality of thermal printing.
An arrangement of transmitter and receiver arrays for synthesizing acoustical holograms
Authors: Nagai Keinosuke , Kimura Minoru 
Published: July 2007

AbstractA method is discussed for synthesizing acoustic holograms consisting of MN pieces of data with M transmitters and N receivers in an acoustic hologram imaging system. Several methods similar to the approach presented here for reducing the total number of transmitters and receivers are examined. the distinctive feature of the proposed method lies in the arrangement of transmitter and receiver arrays on separate planes. the point‐spread function of the synthesized holographic imaging system is computed and the arrangement of transmitter and receiver arrays is restricted so that the grating lobe providing narrower separation is eliminated. the arrangement obtained is a generalization of the well‐known multibeam method in that the transmitter and receiver surfaces are separated. Hence it is applicable not only to reflection holograms but also to transmission holograms. It is also shown that under these conditions the numerical image reconstructed from a hologram can be realized by a single application of the discrete Fourier transform of the MN data. Finally, the results of experimental and numerical simulations are shown and the validity of the proposed method is confirmed.
Analysis of the GI/G/1 queue by the supplementary variables approach
Authors: Komota Yasuo , Nogami Shinya , Hoshiko Yukio 
Published: July 2007

AbstractThis paper analyzes the GI/G/ 1 queue on FIFO discipline by the supplementary variables approach. Using the residual interar‐rival time and the remaining service time of a customer being served as supplementary variables, we derive the basic equations describing the behavior of the system. From the basic equations, characteristic quantities of the system in the steady state are discussed. On the basis of Laplace transform and generating function expression, Laplace transform of actual waiting time is obtained by performing a Wiener‐Hopf decomposition. From this result, Laplace transforms of virtual waiting time, length of an idle period and inter‐departure time and the distributions of the number of customers at the moment just before an arrival and at an arbitrary moment, are derived. Furthermore, it is revealed that the analysis of busy period is reduced to a generalized Wiener‐Hopf decomposition problem. Finally, an application of the general results to the GI/Kn/1 queue is considered and by indicating that the results agree with the known results, the validity of this approach is confirmed.
A type of centrality functions for a directed graph
Authors: Kishi Genya , Takeuchi Masashi 
Published: July 2007

AbstractIn an undirected graph obtained by abstracting traffic and communication networks, evaluation of the centrality of a vertex is interesting from the viewpoint of graph theory. the purpose of discussion of the centrality function is to provide a theoretical basis for solution of the problem. This paper is an attempt to extend the notion of the centrality function defined for the ujidirected graph to the directed graph. the existence conditions of the quasi‐stable and unstable graphs for the centrality functions with general coefficients are derived from the viewpoint of structural stability of the undirected graphs, for which the classification of the graphs is made by the shift of the center by adding an edge with the central vertex as an end point. Furthermore, the stability of the directed graphs is discussed.
A synthesis method for the variable equalizers containing two kinds of variable parameters
Authors: Kawakami Atsushi , Takahashi Shin‐Ichi 
Published: July 2007

AbstractThis paper describes a synthesis method for the two‐variable variable equalizer which contains the parameter μ corresponding to the line length, and the parameter α which is independent of μ and represents the effect of the external factor. the variable transmission characteristic is represented approximately by a polynomialtype transfer function which is a mixed function of μ and a function containing α, which represents approximately the reference attenuation. This characteristic is realized by the state‐space method. By this method, an approximated transfer function is obtained taking the frequency band for the equalization into consideration, and the stability of the approximated function is secured. In addition, the construction with the minimal number of both the network providing the reference attenuation and the variable element corresponding to μ is impossible and the values of the elements are obtained directly from the coefficients of the transfer function. These are the merits of the proposed method over the traditional ones.
Strength assurance of optical fiber based on screening test
Authors: Mitsunaga Yutaka , Katsuyama Yutaka , Kobayashi Hirokazu , Ishida Yukinori 
Published: July 2007

AbstractOne of the most important problems in the practical application of optical transmission systems is to evaluate the reliability of the fiber in optical cable. This paper discusses reliability assurance by screening test, which is the most effective method for reliability evaluation of optical fiber strength. the condition for reliability assurance is discussed, considering the effect of such environments as water and of temperature, time‐varying strain and the distribution of strain along the longitudinal direction of the fiber. the parameters used in representing the strength distribution and fatigue characteristics of the optical fiber, which are needed in the reliability assurance, are quantitatively evaluated based on various kinds of test data. Through discussion of the permissible failure probability of the optical fiber which is required in reliability assurance of the optical transmission system, the condition for the screening test is stated.
A proposed adaptive control method for packet transmission delay in packet speech system
Authors: Suzuki Michio , Kashio Jiro , Toki Ryuichi , Kato Takao 
Published: July 2007

AbstractThere are two basic problems in speech packet switching systems. One is how to guarantee the synthesized speech quality against fluctuation of the mean and variance of packet transmission delay in the network due to traffic fluctuation in packet switching. the other is the problem of deciding the beginning time of the talkspurt synthesis (i.e., when to begin talkspurt synthesis at the receiver side). Under the assumption that the packet transmission delay time is approximated by an exponential function, it is shown that the jitter absorbing time for each talkspurt can be calculated by observation of the packet arrival time at the receiver side. Using this result, an adaptive control method is presented to cope with the above two problems, where the jitter absorbing time is changed according to network traffic changes and the talkspurt synthesis time is determined from several packet arrival times. It is shown from simulation and numerical calculation that application of this control method to a speech packet switching system permits guaranteeing the voice quality in spite of traffic fluctuation in the network and reducing the probability of late beginning of talkspurt synthesis.
Quasi‐one‐dimensional volume‐type hologram memory
Authors: Chang Jon‐Chi , Okoshi Takanori 
Published: July 2007

AbstractWhen two different wavelengths are used for recording and reading in a volumetype hologram memory, construction of a space modulator and photodiode array becomes difficult because unwanted patches appear on a reconstructed image. This can be avoided in a one‐dimensional hologram; however, storage density is reduced. This paper proposes a quasi‐one‐dimensional volume‐type hologram which preserves thick film memory (high density memory) while configuration of a space modulator and a photodiode array is simplified and simultaneous reading at different wavelengths is possible. With a PMMA film with thickness 400 μm a storage density of (0.3 ∼ 1.0) × 105 bits/mm2 was realized, Conditions for simultaneous reading at a different wavelength have been clarified.
An ultra‐high‐voltage high‐speed switching power transistor with new fine emitter structure
Authors: Nakatani Yasutaka , Kuryu Isanu 
Published: July 2007

AbstractAlong with the trend toward smaller size and lower energy consumption in electronic equipment, the dc stabilized power supply has been changed from the series dropping to the switching version, which tan he made more compact and light with high efficiency. the switching frequency in these efforts has increased with each year.Component parts are required for performance in higher frequency regions and it is also hoped that switching transistors will be improved in terms of high speed and large safe operating area. High‐speed switching and large safe operating area have hitherto progressed in a trade‐off relation. This was overcome by decreasing the base resistance via S‐parameter analysis. A newly developed fine emitter structure and oxide planar structure have led to creation of an excellent switching power transistor possessing ultra‐high voltage (1200 V), high‐speed switching characteristics (rise time tr = 200 ns, storage time tstg 2500 nsec, fall time tf = 70 nsec), and large safe operating area (secondary breakdown onset current Isb = 8 A, collector * emitter clamp voltage VCEX(clamp) = 90 V).
Arithmetically symmetrical digital bandpass and band‐elimination filter design by frequency transformation
Authors: Takebe Tsuyoshi , Wakabayashi Masakazu , Nishikawa Kiyoshi 
Published: July 2007

AbstractIn transmission systems of modulated data or picture signals, bandpass filters are required with symmetrical amplitude and delay characteristics around their own center frequencies on an arithmetic frequency scale. In variable attenuation equalizers, etc., band‐elimination filters are required with arithmetically symmetrical stopband amplitude characteristics around the center frequency. This paper proposes frequency transformations to make an analog bandpass filter and a band‐elimination filter (with geometrically symmetrical amplitude characteristics around the center frequencies that are obtained through reactance frequency transformation from analog lowpass filters) into a digital bandpass filter and a band‐elimination filter with arithmetically symmetrical amplitude characteristics. This transformation maps the positive imaginary axis and the negative real axis of analog frequency S to the real axis and the upper half of the unit circle on the z‐plane. the interval on the unit circle of the z‐plane mapping of the positive imaginary axis of the S‐plane is designed to cover the specified frequency region. This is done by controlling the locations of geometrically symmetrical two frequency points around the center frequency of bandpass (band‐elimination) filter by adjusting the parameters of lowpass‐bandpass (band‐elimination) transformation. Some design examples are also shown.
SbEC‐DbED codes derived from experiments on a computer for semiconductor memory systems
Authors: Itoh Hideo , Nakamichi Matsuroh 
Published: July 2007

AbstractSingle byte (= b bits) error‐correcting and double byte error‐detecting (SbEC‐DbED) codes are useful for semiconductor memory systems with memory chips of b‐bit output per one address. In this paper, codes with information length k up to k = 128 bit for 2 b 8 are derived experimentally using a computer. As a result, codes with longer code lengths than before are obtained. In particular, as for the codes of b = 2 and k = 64, 12 check bits were required in the conventional codes, but the codes requiring only 10 check bits are derived by experiments and are an excellent result from a practical viewpoint too. In the derivation, each column in an H matrix of the code is regarded as an element in a Galois field GF (qr) where q = 2b (b is the number of bits in a byte) and r is the number of check bytes. to obtain codes with large code length, as many elements as possible are selected in GF(qr) satisfying the code condition. Here, a subset in a GF(qr) whose elements are linearly independent, is used to select the columns of the H matrix. Moreover, all the elements of GF(qr) arising as operation results in the derivation process can be in correspondence to the elements of the subset. Consequently, the objective sets are restricted and the derivation through computer experiments is facilitated.
Scattering of plane electromagnetic waves by conducting rectangular cylinders ‐a horizontal polarization case ‐
Authors: Hinata Takahashi , Yamasaki Tsuneki , Tamura Masahiko , Hosono Toshio 
Published: July 2007

AbstractThis paper presents a numerical analysis for the scattering of horizontally polarized waves incident on a conducting rectangular cylinder (cross‐section = 2a × 2b) by using the point matching method (PMM). the order of simultaneous equations in the analysis has been reduced to one‐fourth by using the four‐phase symmetrical coordinate method. This has led to a high accuracy of the analysis even for large values of kp0 (k: wavenumber, p0 = √a2 + b2. This paper presents also the numerical results of scattering electromagnetic fields by a conducting rectangular cylinder lying on a flat ground (x‐z plane) which are derived from the two components of four‐phase symmetrical coordinate analysis satisfying the boundary conditions on the x‐z plane. to obtain our numerical results, we did the following: (1) made comparison with the results and discussions of others on similarities and discrepancies among those results, which have led to the justification of PMM, (2) presentation of high‐precision results by PMM for the problems which were analyzed with poor accuracy by other researchers; (3) presentation of scattered far‐field patterns by the skyscraper “Sunshine‐60” in Tokyo as an example for a large value of kp0 = 84.73, comparing vertical polarization. Lastly, a simple method is proposed to calculate approximate scattering fields for large values of kp0 the applicability limit if shown for this approximation method by comparing those results with the accurate results by PMM.
Mutual coupling effects on characteristics of turnstile spherical array antenna
Authors: Horiguchi Susumu , Ishizone Takayuki , Mushiake Yasuto 
Published: July 2007

AbstractMutual coupling between antenna elements is one of the greatest problems when a hemispherical scan coverage array antenna of the spherical type is used. Study of mutual coupling of antenna beam scanning has not been thoroughly investigated. This paper studies the method of analysis for the impedances of dipole antennas over a conducting sphere. Theoretical results have been confirmed by experiments. the active impedance distribution and its scanning characteristics are discussed taking into account mutual coupling in the turnstile spherical array antenna with this method. It is shown that mismatching of the impedance is very small at feeding points. Analysis has been extended to the effects of mutual coupling on scanning characteristics of the power gain and the axial ratio of the polarization. It is found that the turnstile spherical array antenna is suitable for wide scanning from the standpoint of the feeding system.
A realization of low‐power supplies using switched‐capacitor transformers and its analysis
Authors: Oota Ichirou , Inoue Takahiro , Ueno Fumio 
Published: July 2007

AbstractA switched‐capacitor transformer is a coil‐less transformer in which stepping‐up and ‐down of voltage is handled by switching the connections between capacitors alternately into series and parallel. This paper demonstrates that a low‐power coil‐less power supply can be created with these transformers. the proposed circuit has the following features: (1) High efficiency, comparable to that of a switching regulator, can be obtained easily. (2) Because of its coil‐less construction, it can be made small and light. Hybrid integration is also possible. (3) Coil‐less construction significantly reduces generation of magnetic fields. the operating principle is first shown for the circuit with ideal elements. State equations are then derived in which the on‐resistance of the switch element is considered, and these are numerically analyzed. an SC transformer with a transformer ratio of 1/2 and an SC dc‐dc converter with an output voltage regulator already have been constructed with discrete components. Results of the average output voltage and efficiency have been confirmed numerically by experiments on constructed circuits. A comparison of the above two circuits demonstrates that although the latter has an efficiency of about 80% (which is lower than that of the former), both have less than ±0.06% in input‐output variation. the voltage variation is at most ‐0.16% for the temperature variation of −20° ∼ 80°.
Decoding method for doubly encoded reed‐solomon codes and their error probabilities
Authors: Imai Hideki , Yashiro Mitsuhiko 
Published: July 2007

AbstractA doubly encoded Reed‐Solomon (RS) code is a code obtained by encoding the RS code twice. In general, doubly encoded codes are derived from some simple codes to achieve high error correctability. Each step of the double decoding can be implemented easier than a single step decoding of codes with long code length which have a comparable error‐correctability. Furthermore, the doubly encoded codes are suitable for correcting both random and burst errors. This paper describes a decoding scheme for doubly encoded RS codes and discusses its performance. Data and facts obtained during the first step of decoding are used in the second step of the decoding. Even though it is difficult to obtain the optimum decoding scheme, this paper describes an algorithm that renders near‐optimum outcomes. Using CIRC as an example, the selection of a decoding scheme and its superior performance compared to that of the existing scheme are demonstrated. Furthermore, equations are presented for the approximations of various decoding performance parameters. These approximations are quite accurate compared to the exact values, and can reduce a considerable amount of computation time.
Traffic analysis of PRT gradecrossed intersection
Authors: Kurihara Masahito , Kaji Ikuo , Nakada Katsuhiro , Hamamatsu Yoshio 
Published: July 2007

AbstractA gradecrossed intersection of the personal rapid transit system (PRT), which is one of the automated guideway transit systems, is modeled. Its control algorithm which assigns moving cells to avoid vehicle collision at intersection part or the merging part is presented. the algorithm is based on a “first‐come, first‐served” principle and no priority between the two intersected lines is introduced. In both lines, the same upper bound is set for the length of forward and backward maneuvering. When the maneuver length is likely to exceed this upper bound, the vehicle is forced to diverge even if it was to go straight, so that the maneuver length does not exceed the upper bound.To analyze the behavior of this model from the probability theoretical viewpoint, the state is defined based on the maneuver length of vehicles at each time instance synchronous to cell arrival. Thus, the model is formulated as a finite Markov chain (one‐dimensional random walk). As a result, the relation between vehicle traffic density and (1) delay distribution and expected delay time due to intersection passing, (2) abort rate, and (3) throughput, is obtained explicitly.
Distribution of absorbed power inside a sphere simulating the human head in the near field of of a λ/2 dipole antenna
Authors: Amemiya Yoshifumi , Uebayashi Shinji 
Published: July 2007

AbstractIn the new radio frequency protection guide for human exposures to electromagnetic fields recently accepted by ANSI C95, low power devices such as portable radio transmitters are treated as exceptions. This is based on the consideration that these devices may generate fields which, although exceeding the protection guide locally, result in a significantly lower rate of energy absorption for whole body. However, we consider that the localized fields have serious effect at least on the eyes where heat convection due to blood flow is very small. This paper presents the distribution of the absorbed power in the model of a human head exposed in the immediate vicinity of a portable transmitter. In our calculation, the head is simulated by a homogeneous lossy sphere, and λ/2 dipole antenna is used for a portable transmitter. It is found that the local absorbed power is extremely large at the nearest surface of the sphere to the antenna, although the average value is sufficiently small. the peak absorbed power is so large that we believe the reason for excluding low power devices from the ANSI guideline should be reconsidered.
Performance analysis of CSMA/CD protocol with Backoff algorithms
Authors: Iida Ichiro , Yasuda Yasuhiko 
Published: July 2007

AbstractIn recent years the CSMA/CD level area network has been in wide use. However, most of the performance analyses treating stability made so far have been based on the model of a nonpersistent protocol slotted by the propagation delay, which does not represent exactly the actual system. This paper presents the delay and stability analyses of an asynchronous 1‐persistent CSMA/CD scheme with the binary exponential backoff used in the Ethernet. Since this analysis method can be applied to a nonpersistent CSMA/CD scheme or the slotted scheme under the same model, the characteristic difference between the schemes can be clarified. Further, the backoff algorithms can be analyzed under the model representing the actual system. the results of this analysis show that the 1‐persistent CSMA/CD scheme gives smaller throughput and stability than the nonpersistent scheme, and that the previous model gives results that are too optimistic.It is shown also that the binary exponential backoff is far from optimum in the throughput‐delay characteristics and the noadaptation scheme works satisfactorily under the usual condition with small propagation delay.