bluuebunny/crossref_metadata_2025_split huggingface dataset:
Network constructing algorithm based on link significance evaluation‐nable
Authors: Ikeuchi Noriyuki 
Published: July 2007

AbstractA new network design algorithm called “NABLE” (network constructing algorithm based on link significance evaluation) is proposed for constructing future circuit‐switched telecommunications networks. First, this algorithm creates synthetically a backbone network by utilizing a new concept called “link significance.” Then it adds other links to the created network. The flowchart for constructing a network based on this concept is explained. Design examples on digital 64 kbit/s and high‐speed/ broadband circuit‐switched networks show that NABLE is a powerful heuristic algorithm for total network optimization. NABLE can be used in practice for the long‐range planning of various types of networks.
Design and implementation of protocol conversion equipment for layered protocols
Authors: Ideguchi Tetsuo , Nonmember Yuuji Koui, , Tsuchida Mitsuru , Nonmember Yukio Ushisako, , Ishizaka Michihiro 
Published: July 2007

AbstractIn the information communication system it is necessary to establish the protocol conversion, network connection and media conversion techniques to realize communications among computers and terminals with different communication protocols. This paper considers the hierarchical protocol defined based on the OSI basic reference model, and discusses the protocol conversion method together with its realization. A versatile method is introduced in the proposed hierarchical protocol conversion system, in which a protocol conversion can be made from PAD function for various terminals as well as from the nonprocedural level to the personal computer communication protocol recommended by the Ministry of Posts and Telecommunications. The protocol conversion equipment developed based on the proposed idea is demonstrated, and its usefulness is indicated.
Test sequence generation method for systems‐based finite automata–single transition checking method using w set
Authors: Sato Fumiaki , Munemori Jun , Mizuno Tadanori , Ideguchi Tetsuo 
Published: July 2007

AbstractWhen testing communication systems, it is necessary to select the test sequence from the specification. Since the test sequence must be selected manually, the confidence in the testing is low and the testing cost is high. Therefore, we are studying a tool to generate the test sequence automatically from the state table, based on a finite state machine (FSM) model.The PW method and the DS method are presently used to generate a sequence that has a great error detection capability. However, both the PW method and the DS method have disadvantages.This paper presents a new method for the generation of the test input sequence for a system based on an FSM. The method is called the SW method (single transition checking method using W set), and uses the state transition checking approach and the characterization set (W set) for state distinction. This paper also presents an evaluation of this method in terms of its generated test sequence length, its error detection capability, and its general applicability. The results of the evaluation show that the SW method improves some of the weak points of the existing PW and DS methods.
Theoretical analysis of optical fiber strength by bending test
Authors: Tachikura Masao 
Published: July 2007

AbstractThe bend strength of an optical silica fiber tested by deforming fibers in a U‐shape in a pair of parallel plates has been analyzed theoretically by considering the dynamic fatigue of fibers. By assuming that the fiber initial strength follows Weibull distribution, the following results are obtained:

The bend strength follows Weibull distribution but the Weibull exponent is different from that of the tensile strength.
The fatigue constant n of fibers can be evaluated by using the bending velocity dependence of the bend strength.
The distribution of the bend strength can easily be translated into the tensile strength by an approximate calculation without integration.
Automatic pursuit routing for mobile communications network
Authors: Nakajima Akihisa , Yamamoto Koji , Sawada Hiroshi 
Published: July 2007

AbstractThis paper describes an automatic pursuit routing capability necessary for a public land mobile network because mobile stations move freely through service areas. The purpose of pursuit routing is to automatically deliver calls to the called mobile station through the best route. Callers can dial without knowing the actual location of the called mobile station. Automatic pursuit routing requires three logical functions of the mobile communication control center (MCC): the gateway MCC, the home MCC, and the visited MCC. The charging method, numbering plan, and the signaling architecture for implementation are also described, and the effects of the APR and the MCC logical function capabilities are discussed.
Survey on traffic control in atm networks based on traffic theory
Authors: Murata Masayuki , Miyahara Hideo , Oie Yuji 
Published: July 2007

AbstractThis paper presents a survey on the result of researches on the traffic control in the ATM network, together with future problems. In the ATM network, all data are transmitted, being divided into fixed‐length blocks of several tens Bytes called cells. Consequently, a new traffic model is required which is different from the conventional models.As the traffic model suited to the ATM network, this paper discusses first the model which considers the burstiness of the traffic. The purpose in constructing an ATM network is to provide an efficient channel for various media with diversified traffic patterns, from the low speed to the high speed, in the multimedia environment by utilizing the effect of the statistical multiplexing.Next, the traffic multiplexing effect is discussed considering the burstiness of the traffic. Finally, as the traffic control required in the ATM network to satisfy the “communication quality depending on each medium,” a control method is discussed which considers more than one processing class.
Cell loss protection using hierarchical coding in video packet communication
Authors: Katto Jiro , Yasuda Yasuhiko 
Published: July 2007

AbstractAs a promising means of realizing broadband ISDN, the ATM (asynchronous transfer mode), which is based on fast packet switching, is considered interesting. In video communication by ATM, the constancy and improvement of picture quality by variable rate coding is expected, while the quality deterioration by cell loss is a serious problem.This paper proposes a video coding method introducing hierarchical coding to cope with the cell loss problem. The proposed hierarchical coding extracts the low‐frequency components of the image by iterating the hierarchical processing based on the spatial filter. Then it is possible to suppress the effect of the quality deterioration caused by cell loss, as long as the low‐frequency components are retained.First, the configuration of the proposed system is discussed. Simulations are executed to observe the effect of the cell loss and the coding characteristics, demonstrating the effectiveness of the proposed method in coping with the cell loss. Then discussions are made on the optimal number of hierarchical processings to cope with the cell loss and the protection level for hierarchical information. Furthermore, it is shown that a new type of video communication can be realized by introducing hierarchical coding.
Design of a nondissipative lc snubber in a forward converter
Authors: Ninomiya Tamotsu , Tanaka Tetsuro , Harada Koosuke 
Published: July 2007

AbstractA snubber circuit protects semiconductor switches in a dc‐dc converter from voltage stresses. The snubber composed of a resistor and a capacitor, namely theRCsnubber, is used widely for protection circuit, although the power dissipation inRCsnubbers deteriorates the power efficiency of converters. To remedy this drawback, a nondissipativeLCsnubber composed of an inductor, a capacitor and diodes has been developed.TheLCsnubber is not only nondissipative in principle but also has a feature to reduce the switching power‐loss in semiconductor switches. As for the design of the snubbers, for theRCsnubbers the power dissipation in the snubber circuit is the point to be considered; and for theLCsnubber, the power loss in the semiconductor switch is taken as a criterion from its features.In this paper, the design procedure of theLCsnubber in a forward converter is discussed in the following order: First, the operation of a forward converter with theLCsnubber is examined. Next, the energy loss in a switching transistor is evaluated, and the condition to minimize this energy loss is provided. As a result, the procedure to determine the optimum values of the snubber capacitor and snubber inductor is reported.
Properties of linearly steep tapered cutoff waveguide filters
Authors: Suga Takashi , Shirasaki Hirokimi , Ishihara Fujio 
Published: July 2007

AbstractThe properties of linearly steep, tapered cut‐off waveguide filters are analyzed by the eigenmode expanding method. Coupling from higher modes to the fundamental mode and coupling between higher modes have been taken into account in order to get exact results. The numerical results of the reflectional loss are in good agreement with the experimental results over a wide range from one‐wavelength tapered waveguides to a step‐connected waveguide. The effect of higher modes is marked in asymmetric waveguides and very steep waveguides, and is shown by the down shifting of the first resonant frequency.
Satellite and terrestrial link switching control method using high‐speed time‐division multiplexer
Authors: Shinnai Kohsuke , Nakamura Tsutomu , Suzuki Michio , Sasaki Ryoichi , Takahashi Hiroaki , Matsuura Akio 
Published: July 2007

AbstractThe mixed media network including the terrestrial and the satellite communication links is considered, aiming at the realization of a highly reliable information network. This paper proposes a method of physical level switching control in the highspeed multiplexer between the terrestrial and the satellite links.The following three aspects of the physical level switching control method are described. The high‐speed digital network management system instructs the link switching to the high‐speed multiplexer according to detected faults. The high‐speed multiplexer has a function to handle equally the high‐speed digital link and the satellite link.The Earth station has the interface function which enables the high‐speed multiplexer to switch the master clock. This paper outlines the switching control method at the physical level using the high‐speed multiplexer in the transmission network. It discusses also the technical issues as well as their solutions in the implementation, such as the loss of paths for managing information, management of intermittent faults and switching of the master clock.The link switching experiments actually are made between the earth and the satellite in the “pilot study for use of satellite,” underwritten by the Min. Post & Telecomm. The time from the fault detection to the complete link switching in the proposed network management system is within 30 s, indicating the effectiveness of the proposed switching control method.
An approximate analysis of a queueing system with markov‐modulated arrivals
Authors: Takahashi Haruhisa , Wang Li‐Sheng 
Published: July 2007

AbstractThis paper presents an excellent two‐moment approximation via an N‐environment diffusion model of a queueing system with Markov modulated Poisson process (MMPP) arrivals and general service time distribution. By choosing residual workload as a performance criterion, an approximation error of less than 3 percent can be achieved.We give a closed form solution for all moments of the waiting time distribution with two‐state MMPP arrivals. We also propose an algorithm for the approximate solution of single server queueing systems with n‐state MMPP arrivals. The proposed sufficiency condition for the existence of a stationary solution has not been proved for the n‐state case with n ≥ 3.
Small‐signal dynamic analysis of class e resonant dc‐dc converter regulated by an auxiliary switch
Authors: Gu Wen‐Jian , Harada Koosuke 
Published: July 2007

AbstractSmall‐signal dynamic analysis of a class E resonant dc‐dc converter is presented where voltage regulation is done by an auxiliary switch without changing the switching frequency. This converter is suitable for high‐frequency operation because both the main and the auxiliary switches can be turned ON/OFF at zero voltage level and the switching loss is very low.Small‐signal dynamic characteristics are determined by an averaging model obtained by the use of Fourier series expansion where the terms higher than second order have been neglected. Experiments are performed on a 1‐MHz switching converter and the applicability of this analysis is verified.
A token‐passing scheme in a time‐division multiplexed local area network and its performance evaluation
Authors: Ishizaka Michihiro , Shikama Toshihiro 
Published: July 2007

AbstractThis paper considers an access scheme to realize a packet switching function using the time‐division multiplexed frame which circulates on a ring‐type backbone LAN. A slotted token‐passing scheme is proposed which enables a long packet transmission by concatenating the time‐division slots available by dividing the frame. Its access control algorithm and the recovery mechanism from ring failure are shown, along with the numerical analysis of the mean transfer time of the proposed scheme by comparison with the token ring access scheme of ISO (ISO 8807/5). The communication performance is evaluated from the viewpoints of the number of stations, packet length, transmission rate, etc. As a result, it is demonstrated that the slotted token passing scheme proposed as the packet switching function for the time‐division multiplexed ring is effective for high‐speed LANs having heavy traffic loads with a large number of stations and a long transmission line.
High‐performance unidirectional bus lan in the case of large‐sized network
Authors: Asano Hitoshi , Masuda Takao 
Published: July 2007

AbstractA new unidirectional LAN called SURVIVALNET, suitable to high‐speed integrated (HSI) LAN, is proposed. It has a function of controlling transmission by sensing a carrier not only on the outbound as in the case of DAMA but also on the inbound channel. Therefore, high channel utilization and short packet delay can be realized even if the network size becomes large.This paper describes first the principle of SURVIVALNET. Second, its channel utilization is discussed analytically under both light and maximum load and analyzed numerically under medium load using computer simulation. Finally, it is shown that the SURVIVALNET is applicable to HSI LAN.
A numerical method to evaluate frequency modulation/demodulation limit of phase‐locked loop
Authors: Takahashi Yutaka , Bamba Eiichi , Kinemura Kazuhiro 
Published: July 2007

AbstractA method is presented in this paper to determine the FM modulation/demodulation limit by numerical calculation. This is the synchronization limit when a phase‐locked loop is used as an FM modulator or demodulator. It is shown that the same differential equation can be used both for modulation and demodulation to describe the behavior of the phase‐locked loop for the FM signal. An algorithm is shown which solves the derived equation, which is nonlinear in general, by the harmonic analysis, and derives the periodic solution with the same period as that of the modulating signal by a numerical calculation. The limit of existence for the stable periodic solution is the limit of synchronization.A method is presented which can determine the limit. A phase‐locked loop with a sinusoidal phase comparator and an adequate loop filter is considered as an example. The periodic solution is actually calculated and the FM modulation/demodulation limit is determined from the limit of stability. The obtained result can be accounted for qualitatively and agrees with the experimentally obtained result.
Error rate analysis in mdpsk and mcpsk with a pilot on satellite‐aircraft multipath channel
Authors: Miyagaki Yoshiya 
Published: July 2007

AbstractThe multipath channel between a satellite and an aircraft is modeled as direct wave + mirror reflected interference wave + scattered interference wave + receiver thermal noise. The symbol error rate in the channel is analyzed theoretically by strict and approximate methods for the case where the multiphase phase‐modulated wave is received by delayed detection (MDPSK) and for the case where the pilot wave is added and synchronous detection is made (MCPSK). As a result, it is seen that MDPSK is better when the direct wave‐to‐noise power ratio is less than 20 dB and MCPSK is better when it is larger than 20 dB.
Overlapping block discrete cosine transform coding and its fast algorithm
Authors: Sawami Hideo , Morikawa Yoshitaka , Hamada Hiroshi 
Published: July 2007

AbstractThe discrete cosine transform (DCT) method is well known for a highly efficient coding for still images. A problem in this method is that the block distortion is observed in low‐rate coding. The overlapping block transform (OBT) has recently been proposed, aiming at the reduction of the block distortion. OBT is derived as a frequency analyzer/synthesizer with the origin of the spatial coordinate at the mid‐point between the sampling points and the main processing operation results in a DCT of unordinary type. This increases the computational complexity compared to the ordinary DCT.From such a viewpoint, this paper first derives the overlapping block DCT (OBDCT) with the same main processing as that of the ordinary DCT, by placing the origin of the spatial coordinate at the sampling point. OBDCT has the same coding efficiency as that of the traditional OBT, and OBDCT with the transform length 8 has the same coding efficiency as that of DCT with the transform length 16. A fast OBDCT algorithm is derived by integrating and simplifying the proposed OBDCT and the transform processing. Finally, it is shown that the fast OBDCT with the forementioned transform length can be executed by 55 percent of multiplications of the fast OBT and 67 percent of the fast DCT.
An estimation formula of received power space correlation coefficient using three‐ray model
Authors: Sasaki Osamu , Satoh Akio , Hosoya Yoshio 
Published: July 2007

AbstractThis paper derives an estimating equation for the received power space‐correlation coefficient needed for the design of a space diversity receiving system for improved transmission performance of a microwave relay system as a semiempirical equation based on the theoretical investigation, with corrections by measured data, from a three‐ray model in which the received wave consists of the direct wave, reflected wave, and duct refractive wave. This equation is determined from the amplitude statistics of the three waves, the propagation conditions such as the distance and the transmitter and receiver heights, the frequency and the radio meteorological statistics. This model contains the two‐ray model method intended for a propagation path with a strong reflection (strong reflection link) and the Makino‐Morita method which assumes Rayleigh fading for a propagation path with a weak reflection (weak reflection link). The measured results of the spatial‐correlation coefficient of the received power in about 30 links measured in Japan, including both the strong and weak reflection links, are found to agree well with the estimated values based on the present equation. Hence, the effectiveness of the estimation equation proposed in this paper is confirmed.
Analysis of a planar inverted‐f antenna by spatial network method
Authors: Taga Tokio , Tsunoda Kikuo 
Published: July 2007

AbstractBy means of the spatial network method, the characteristics of a planar inverted‐F antenna on an infinite ground plane are analyzed. The electric field between the planar element and ground plane and the surface current distribution on the antenna for different values of the width of the short‐circuit plate are found. In addition, by Fourier transform of the impulse response of the antenna, the resonant frequency and the bandwidth are derived. The relationship between the width of the short‐circuit plate and the path length of the antenna current flowing on the planar element, short‐circuit plate and ground lane also is studied. An approximate formula is investigated for the resonant frequency as a function of the width of the short‐circuit plate, dimensions of the planar element and antenna height. Further, by comparison with the measured results, the validity of the analysis results is confirmed.
Interference canceling characteristics of diversity reception with least‐squares combining—MMSE characteristics and ber performance
Authors: Suzuki Hiroshi 
Published: July 2007

AbstractThis paper discusses theoretically several characteristics of diversity reception with least‐squares combining. Least‐squares combining minimizes the combined signal error from a reference signal by the least‐squares method. Values of complex coefficients and resulting minimum mean‐square error (MMSE) are derived first on the assumption that the desired and interference signals are mutually independent. The general solutions are applied to two‐branch diversity reception, and an explicit formula that determines the CNR of the combined signal is obtained.The diversity performance is discussed from two aspects: signal combining and interference canceling. The discussions show that: (i) maximal ratio combining is achieved if there is no interference; (ii) if there is a single interference source, the interference can be canceled completely and one branch signal reception performance is obtained; and (iii) if there are two or more interference sources, the interference cannot be canceled completed and the diversity performance degrades severely. Furthermore, computer simulations determined the instantaneous CNR distribution functions and average BER performance characteristics.
Validation method for telecommunications protocol with internal events
Authors: Wakahara Yasushi , Kakuda Yoshiaki 
Published: July 2007

AbstractThis paper proposes a new method for efficient validation of the telecommunication protocol, containing the internal events, including those for the timer and resource management. The proposed validation method first converts the protocol containing the internal event into the equivalent protocol not containing the internal event. Then the original protocol is validated by applying the already‐proposed validation method for the protocol not containing the internal event to the result of conversion.This paper discusses mainly the principle and the algorithm of the protocol equivalent conversion. The features of the proposed validation method are that the protocol is validated with the minimum processes and signals, which reduces the processing time and the memory capacity needed in the validation and also improves the efficiency.
HDTV/TV compatible coding based on intrafield/interframe adaptive LOT and its characteristics
Authors: Jozawa Hirohisa , Watanabe Hiroshi , Hashimoto Hideo 
Published: July 2007

AbstractThis paper describes an HDTV/TV compatible coding method based on lapped orthogonal transform (LOT). With this method, TV signals are obtained by performingN/2‐point inverse LOT to low‐orderN/2 coefficients. It is shown that the LOT domain decimation reduces the aliasing noise in TV images more efficiently than the DCT‐based method. In addition, intrafield/inter‐frame adaptive LOT coding is examined. The experimental results show that the coding efficiency of intrafield/interframe adaptive LOT coding is higher than that of intrafield/interframe adaptive DCT coding. LOT coding improves the SNR by 1 dB in fixed bit rate HDTV coding at 130 Mb/s. By using LOT as a decimation filter as well as a bit rate reduction algorithm in compatible HDTV coding, the quality of the TV images and the coding efficiency are better than with the DCT‐based method.