bluuebunny/crossref_metadata_2025 huggingface dataset:
ChemInform Abstract: Diels‐Alder Cycloadditions: 3‐(p‐Toluenesulfonyl)‐2‐propenal as Dienophile.
Authors: RIAHI A. , MUZART J. , PETE J.‐P.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Structures of 6‐Aryl‐1,5‐dimethoxycarbonyl‐2‐methyl‐4‐ morpholino‐1,3‐cyclohexadienes and Related Compounds.
Authors: NITTA H. , TAKIMOTO K. , UEDA I.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: The Catalytic Pinacol Rearrangement of 1,2‐Diols Using an Antimony(V) Salt.
Authors: HARADA T. , MUKAIYAMA T.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Arene 1,4‐Diradical Formation from o‐Dialkynylarenes.
Authors: SEMMELHACK M. F. , NEU T. , FOUBELO F.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Highly Sterically Hindered Carbon Acids: The Intrinsic Reactivity of 5, 5′,5′′‐Trimethyl‐ and 3,3′,3′′,5,5′,5′′‐Hexamethyl‐2,2′,2′′,4,4′,4′′‐ Hexanitrotriphenylmethanes.
Authors: TERRIER F. , XIAO L. , FARRELL P. G. , MOSKOWITZ D.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Oxidative Dehydrogenation of Ethane and the Coupling of Methane over Sodium Containing Cerium Oxides.
Authors: KENNEDY E. M. , CANT N. W.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Nucleophilic Fluorination of Chlorinated N‐Heterocycles with Tetrabutylphosphonium Hydrogendifluoride and Dihydrogentrifluoride.
Authors: UCHIBORI Y. , UMENO M. , YOSHIOKAI H.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Transformation of Amino Acids. Part 9. Chemoenzymatical Synthesis of N6‐Carbamoyl‐D‐4‐thialysine and N7‐Carbamoyl‐D‐homo‐5‐thialysine.
Authors: DRAUZ K. , KOTTENHAHN M. , KLENK H.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: The Structures and Stereochemistry of the Diels‐Alder Adducts from (E)‐ 2‐Styrylchromones. A Revision of the Xanthene Structures.
Authors: LETCHER R. M. , YUE T.‐Y.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Condensed Heterocyclic Lactams. Part 2. Synthesis of New 4‐ Arylquinolin‐2(1H)‐one Derivatives.
Authors: HAZAI L. , DEAK GY. , TOTH G. , SOHAR P. , TAMAS J. , GYOERGY L.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Efficient Synthesis of 3H,5H‐Pyrrolo(3,2‐d)pyrimidin‐4‐one.
Authors: BRAKTA M. , DAVES G. D. JUN.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis of 9‐Hydroxyalkyl‐Substituted Purines from the Corresponding 4‐(C‐Cyanoformimidoyl)imidazole‐5‐amines.
Authors: BOOTH B. L. , DIAS A. M. , PROENCA M. F.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Platinum‐Catalyzed Novel Reaction of Nitriles and an Azirine with o‐ Bis(dimethylsilyl)benzene.
Authors: REDDY N. P. , UCHIMARU Y. , LAUTENSCHLAGER H.‐J. , TANAKA M.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: A Novel Method for the Preparation of Optically Active Dipeptide. Chemo‐ and Stereoselective Reduction of 2‐Hydroxyimino Amides with Samarium Diiodide.
Authors: MUKAIYAMA T. , YOROZU K. , KATO K. , YAMADA T.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis of Some Halogenated and Disubstituted Amino Benzylacyclouridine Derivatives.
Authors: PAN B.‐C. , CHEN Z.‐H. , ROWE E. C. , CHU S.‐H.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Developments of the New “Experimental Theory” of Sonochemistry Initiated in Grenoble
Authors: LUCHE J. L.
Published: July 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Guidelines for direct marketers to aggregate and analyze third-party complaints
Authors: Schibrowsky John A. , Lapidus Richard S.
Published: July 2007

Most direct marketers have invested in complaint programs designed to handle individual complaints. However, an increasing number of direct marketing customers are filing third-party complaints. This article is designed to help in reversing that trend by forwarding a proactive approach to managing complaints. It presents a method to aggregate, analyze, and manage third-party complaints. This is a necessary part of a total complaint management program.
Issues and problems in applying neural computing to target marketing
Authors: Zahavl Jacob , Levin Nissan
Published: July 2007

Applying a neural network (NN) to the targeting and prediction problems in target marketing poses some unique problems and difficulties unparalleled in other business applications of neural computations. We discuss several of these issues in this article, as applied to solo mailings, offer remedies to some, and discuss possible solutions to others. A numerical example, using NN backpropagation models and involving realistic data, is used to exemplify some of the resulting issues.
Performance evaluation of a multi‐microprocessor simulator for communications networks
Authors: Inamori Hisayoshi , Toda Akira
Published: July 2007

A parallel processing simulator, NEWTS, composed of a number of microprocessors has been developed to evaluate communications networks. This paper describes the key design objectives of NEWTS. We examine the memory size required in a processor to simulate an exchange node and synchronization scheme between processors. We also compare the parallel simulator with a serial simulator from the viewpoint of simulation speed. As a result it is shown that one processor can simulate several queues, the method of updating by one clock is an excellent system synchronization scheme from the viewpoint of simulation speed, and the processing capability of NEWTS is nearly proportional to the number of processors.
Performance of dll for PN sequences with bit errors
Authors: Yamarnoto Zenichi , Nomura Tamiya
Published: July 2007

Tracking performance of DLL (Delay‐Lock Loop) for PN sequences with bit errors is discussed and the relationship between the average bit error rate and the normalized r.m.s. tracking error of one‐Δ DLL, is analyzed using the concept of “error sequence.” As a result, it is clarified that the tracking error is nearly proportional to the average bit error rate pe when the loop band width is narrow and is nearly proportional to Pe when the loop band width is wide. The performance of BPSKC (Binary Phase Shift Keyed Correlation) system is analyzed and compared with conventional noise residual systems. It is demonstrated that the BPSKC system is disadvantageous for the input SNR below a certain level but it has some advantage over other systems for the input SNR beyond this level.
Analysis of roundoff noise in separable‐denominator two‐dimensional digital filters
Authors: Kawamata Masayuki , Kawada Etsuo , Higuchi Tatsuo
Published: July 2007

A tradeoff among filter wordlength, processing precision, and processing speed, is an important subject in realtime twodimensional (2‐D) digital filtering. This paper analyzes the roundoff noise in implementing separable‐denominator 2‐D digital filters with finite wordlength. Separable‐denominator 2‐D digital filters with infinite and finite wordlength are described by Roesser's state space model. The output error variance due to roundoff noise in 2‐D digital filters with finite wordlength is obtained in the state‐space formulation. It is shown via equivalent transformations that the output error variance due to roundoff noise in 2‐D digital filters depends slightly on filter structures. The l2‐norm of 2‐D digital filters is defined, and the l2‐norm scaling is introduced to fully utilize the dynamic range without causing excessive overflows. Finally, the validity of the proposed analysis method of the roundoff noise in separable‐denominator 2‐D digital filters and the structural dependency of the roundoff noise are clarified through numerical examples.
Waveguide type power combining amplifiers
Authors: Toyoda Sachihiro
Published: July 2007

This paper is concerned with the waveguide power combining amplifier of reflection type and of transmission type. The structure of the waveguide reflection type power combining amplifier consists of an IMPATT diode (to be called the active element) under a post at the center of the waveguide and of a shorting plunger. At the distanceZin front of the active device, another active device is placed under a post and an inductive window is located atZin front of this second device. On the other hand, the transmission type (power combining) amplifier consists of an active device under a post located atZfrom an inductive window. Another device is placed under a post atZfurther down the waveguide and an exit inductive window atZfrom the second device. The waveguide height of the two amplifiers are 3 mm for which the stability condition is satisfied for the amplifier. Tapered sections are installed from the reduced height waveguide to standard waveguides.

The equivalent circuits of the two amplifiers have been derived from the electromagnetic field equations. The experiment of the power combining amplifiers have been performed at the 10‐GHz range. The output power is 2.5 mW to 103 mW when the input power was changed from 0.5 mW to 20 mW. The calculated results from the equivalent circuits agree well with the measured data.
Adaptive filtering with input estimation–a tracking filter with input estimation
Authors: Nomoto Kohei , Nojima Hideo , Sato Chikara
Published: July 2007

This paper proposes a tracking filter to track the maneuvering target, controlled by the input which is unknown to the observer. The method estimates the constant component of the acceleration input, which is then utilized in the estimation and prediction of the position and the velocity. In the constant velocity, straight‐line motion, the acceleration of the moving target is only a perturbation of trajectory by turbulence, etc., which can be considered as a noise in the system. However, in circular motion, a considerably large acceleration is continuously added to the fluctuation. Consequently, the acceleration is divided into the system noise and the bias or deterministic input. The latter component is estimated under the assumption that it changes only slowly. The tracking filter is then constructed using the result of the above analysis to the estimation and prediction of the position and the velocity. The proposed tracking filter aims at the adaptation to the nonstationary motion of the maneuvering target and the tracking to both circular and straight line motions. The filtering can be generalized as a method of state estimation including the estimation of input, and one can expect other applications. Finally, the effectiveness of the proposed filter is demonstrated by a simulation.
Estimation method of direct‐radiator loudspeaker system parameters in low‐frequency range by nonlinear optimization technique
Authors: Nomura Yasuo , Ai Takaharu , Fukuda Keiji
Published: July 2007

This paper proposes an estimation method for the system parameters in the low‐frequency range of the direct‐radiator loudspeaker system. The system parameters considered in this paper are defined by the elements in the electrical and mechanical equivalent circuit in the low‐frequency range. In previous estimations of the system parameters, the impedance measurement was required for the driver speaker in the free space or in the standard box. On the other hand the proposed method can provide estimations for the system parameters, including the proper additional air mass and the effective volume of the box for the driver speaker and the passive radiator (drone cone or port), only by the measurement of the system impedance. Consequently, it is a practically useful method. The estimation is made by minimizing (optimizing) the evaluation function by the nonlinear optimization, which is composed of the square sum of the difference between the measured and calculated impedances at the voice‐coil terminals of the driver speaker at a finite number of discrete frequencies. Eight kinds of methods are examined for efficient estimation. By computer simulation and two examinations, the validity and usefulness of the method are indicated. Since the method can provide estimations of the true system parameters, it can present effective means for the system design.
Electromagnetic scattering by perfectly conducting polygonal cylinders
Authors: Sugimoto Satoru , Kawabata Masayuki , Kozaki Shogo
Published: July 2007

Analytical results by the integral equation method are described for the problem of electromagnetic scattering from perfectly conducting polygonal cylinders with TE and TM wave incidence. This approach is extended to the case of TE wave scattering by a set of perfectly conducting polygonal cylinders. In the presence of several conducting cylinders the mutually interacting surface current densities are used for deriving the integral equations. The latter are reduced to simultaneous equations by step function approximations of the current distributions. Numerical examples include the surface current distributions on a concave conducting cylinder and multiple rectangular cylinders and their scattering patterns as well as the near field distributions, which have not been evaluated extensively to date. It is found that a strong standing wave is caused in the electric field between the rectangular cylinders due to multiple scattering. To confirm validity of the theory, a model experiment is performed at microwave frequency. It is confirmed that the theoretical experimental results are in good agreement. The results of the present paper provide a calculation model for wave propagation in an urban community. They can be used as a basis of such propagation.
An approach to the continuous‐time stability criterion of polynomial matrices via orthogonal polynomial matrices
Authors: Nagaoka Hiroshi , Monden Yoshimi , Arimoto Suguru
Published: July 2007

The stability of a scalar polynomial can be tested by the Routh‐Hurwitz method, but a stability criterion for polynomial matrices is not known yet. A square polynomial matrix D(s) is said to be (continuous‐time) stable when all the zeros of det D(s) have negative real parts. In this paper, orthogonal polynomial matrices (Rj(s); j = 0, 1,…; associated with an inner product are considered in studying the stability of D(s). A recursive algorithm to produce {Rj(s)} is presented which elucidates the relation between the stability and the polynomial matrix structure of D(s). When D(s) is a scalar polynomial the algorithm is shown to be equivalent to the Routh‐Hurwitz test. The results are applied to the construction of the Schwartz‐form realizations and the Routh approximations of multi‐variable linear systems.
Construction and analysis of frame synchronization systems taking into account the channel state
Authors: Fuji Tsuyoshi , Sato Masashi , Kasahara Masao , Namekawa Toshihiko
Published: July 2007

When a channel falls out of synchronism, the approximate frame sync position can normally be estimated and this fact can be applied in the design of frame synchronization systems. This paper presents a new multicounter method for the realization of a fast frame synchronization system taking into account the probability distribution of the sync position. There are two typical ways of realizing a multicounter system: the intensive method, and the division method. The refraining characteristics of a multicounter system are demonstrated for particular probability distributions of the sync position. It is shown that the multi‐counter method provides a flexible synchronization strategy by taking account of the state of the channel.
Gain/shape vector quantizer for multidimensional spherically symmetric random source
Authors: Saitoh Takahiro , Takeo Hideya , Harashima Hiroshi , Miyakawa Hiroshi
Published: July 2007

The probability density of normalized ac orthogonal transform coefficients of image data can be modeled as a spherically symmetric distribution. On the other hand, the gain/shape vector quantizer [8] proposed by Buzo et al. is expected to provide a good quantization performance and a flexible design method for spherically symmetric random source. Therefore, it may be possible to realize a flexible vector quantizer by designing a gain/shape vector quantizer in the orthogonal transform domain. With this expectation the asymptotic performance and optimal allocation of the number of quantization levels of the gain/shape vector quantizer for an n‐dimensional spherically symmetric random source was derived and it was shown that for n ≤ 10 the gain/shape vector quantizer yields the asymptotic performance between its upper bounds derived by Zador [10] and those by Conway and Sloane [11], and that for n > 11 its asymptotic performance is similar to the Zador's upper bounds. Also, comparison with the asymptotic performance of scalar quantizers [12] was made and it was shown that possible improvement of coding performance can be obtained by applying the gain/shape vector quantizer to orthogonal transform image coding, for which conventionally scalar quantizers have been used. Furthermore, a simple and flexible design method for the suboptimal gain/shape vector quantizer for a given spherically symmetric distribution was presented.
Approximation of characteristics of networks containing several kinds of variable elements
Authors: Kawakami Atsushi
Published: July 2007

In recent years, the problem of synthesis for frequency characteristics containing several independent variable characteristics has become important in various technical fields (mainly measurement‐control systems and communication systems). This paper proposes a method to approximate such frequency characteristics by rational transfer functions containing several kinds of variable parameters. We restrict ourselves for approximated transfer functions to the sum of rational transfer functions containing only one kind of variable parameter from the viewpoint of easiness of the stability test, and network construction. Moreover, a method is proposed to obtain the approximated transfer functions which are stable in the designated variable range of each variable parameter.
Magnetostriction insensitive dual‐mode phase shifter
Authors: Asao Hideki , Matsunaga Makoto , Takeda Fumio
Published: July 2007

The dual‐mode phase shifter is known as a reciprocal ferrite phase shifter. However, in the dual‐mode phase shifter made of ferrite with magnetostrictive effect such as YIG for high power and low insertion loss applications, the reciprocal characteristics of the insertion phase shift is degraded when an external force is applied. This paper shows theoretically and experimentally that this nonreciprocal insertion phase shift is caused by the circumferential magnetization in the Faraday rotator known as the inverse Wiedemann effect, one of the magnetostrictive effects. The paper describes a method for constructing a dual‐mode phase shifter in which the nonreciprocal insertion phase is cancelled and summarizes the results of the trial fabrication. In the dual‐mode phase shifter cancelling the non‐reciprocal insertion phase developed for the X band application, the nonreciprocal insertion phase shift is less than 2 degrees, that is, one‐tenth that in a conventional device made of identical material.
Transient analysis of coupled microstrip‐slot‐line in three‐dimensional space
Authors: Koike Shoichi , Yoshida Norinobu , Fukai Ichiro
Published: July 2007

Recently, with a view to obtaining an effective function in microwave techniques, double‐side planar circuit technology is being studied. The microstrip‐slot‐line is one such configuration. By changing the strip width, the dispersion characteristics and the impedance can be adjusted. Use of this transmission line in a number of applications has been studied. With the advances in pulse techniques today, it is necessary to perform a three‐dimensional analysis including the transient response so that the structure is rigorously considered in three‐dimensional space. In this paper, a three‐dimensional analysis in the time domain is performed for this transmission line. It is found that the complicated three‐dimensional electromagnetic field can be related to the static pattern corresponding to the even and odd mode at each instance. Hence it became possible to analyze the effects of the conductor shape and the medium conditions. The characteristic impedances and the effective dielectric constants of the even and odd modes have been calculated from the three‐dimensional electromagnetic field distributions. The results have been compared with available numerical results and fundamental agreement has been found. The analysis has also been performed in the wider range of structural parameters and satisfactory results have been obtained. From the steady‐state characteristics, the transient propagation characteristics have been found and the difference in the dispersion characteristics obtained. The property of this transmission line has been described.
Performance characteristics of QPSK signal passing nonlinear channel in digital ship earth station system
Authors: Okinaka Hideo
Published: July 2007

This paper presents the out‐of‐band emission characteristics and the BER performance of the QPSK signal passing a class‐C power amplifier in a ship earth station transmitter and compares them with those of the QPSK signal passing a solid‐state linear power amplifier operating near saturation. The study is made mainly by computer simulation. The results show that the BER performance degradation for the class‐C power amplifier is approximately 0.9 dB at BER of 10‐6 with appropriate filtering when adjacent‐channel interference is absent. This BER performance is almost the same as that for the linear power amplifier. However, the class‐C power amplifier generates a higher level of out‐of‐band emission over a wide frequency range than the linear power amplifier, which in an SCPC system degrades the BER performance of adjacent channels. It is quantitatively shown that larger carrier spacing should be adopted for class‐C power amplifiers than for linear power amplifiers to cope with this degradation. Finally, the feasibility of using a class‐C power amplifier for the ship earth station transmitter is discussed for the digital system employing 36‐kbps QPSK which has been developed for possible INMARSAT application. It is concluded that system operation with 50‐kHz carrier spacing is feasible, while operation with 25‐kHz carrier spacing is infeasible when class‐C transmitters are used. On the other hand, system operation with 25‐kHz carrier spacings is feasible when linear transmitters are used.
A neural network model for the discrimination of spatio‐temporal patterns
Authors: Futami Ryoko , Hoshimiya Nozomu
Published: July 2007

A neural network model which learns to discriminate spatio‐temporal patterns is proposed. This model is composed of pulse‐type neuron models taking account of its realization with hardware. Input pulse trains whose dynamic features are emphasized by ON‐type neurons propagate through the uniform neural chains and are then fed to plastic neuron models which are laterally interconnected with suitable inhibitory/excitatory weights. After iterative training steps, various phases of input spatio‐temporal patterns are reproduced on the spatial patterns of synaptic weights, and plastic neurons are organized to form some functional groups that respond only to some voice features.
An improved Ziv‐lempel coding scheme for universal source coding
Authors: Yokoo Hidetoshi
Published: July 2007

This paper proposes a universal information source code (improved ZL code) based on the Ziv‐Lempel (ZL) incremental parsing algorithm. It is known that a ZL code is asymptotically optimum for a stationary ergodic information source, although it does not utilize the source structure. Its convergence, however, is very slow and it cannot provide efficient compression for an input string of limited length. This paper considers the redundancy of ZL code, which is the reason for the slow convergence. In order to eliminate the redundancy a coding scheme is presented in which only the substring obtained by incremental parsing is used in the next stage. When the substrings of the incremental parsing are separately coded the improved ZL code obtained by the proposed scheme is the least redundant in the sense that the mean code length for the substrings is minimized. In the coding a data structure called modified ZL tree is introduced and its properties discussed together with two coding algorithms based on that structure. The coding is actually performed for the output string from a memory‐less binary source and binary Markov source. It is shown that sufficient compression is realized for a binary code string length of 103 to 104, indicating the possibility as a practical data compression algorithm.
Consideration on a nonlinear multicommodity flow problem in a packet switching network
Authors: Kurosawa Kaoru , Hasebe Takayuki
Published: July 2007

In a packet switching network it is important to route traffic flow so as to minimize message delay. This problem is formulated as a multicommodity flow problem with a nonlinear objective function and it is solved by the steepest descent method. It is also necessary to control the traffic demand at each node so that the total message delay is below a certain level. This paper presents an algorithm to obtain the region vectors consisting of traffic demand at each node which can be transmitted simultaneously under the given delay time. Despite its importance this region has not been adequately considered. A nonlinear T‐cut condition is introduced by which the region is obtained. This paper is a nonlinear extension of the authors' recent work.
Proximity feed microstrip antenna
Authors: Haishi Katsuyuki , Itoh Kiyohiko
Published: July 2007

The proximity feed microstrip antenna (PMA) fed via a gap enables switching of the polarization with a simple operation of opening or shorting the end of the feed. However, since the PMA is coupled electromagnetically with the feed line printed on the same surface as the antenna, the effect of the feed line on the antenna characteristics is expected. In this paper, the full‐wave analysis developed by Itoh et al. is used for the analysis of the antenna system including the feed line. In this method, Galerkin's method is used in the Fourier transform domain. The effects of the feed line on the resonant frequencies and the radiation patterns of the PMA are investigated. The application of the PMA to a circularly polarized antenna has been tried and actual generations of circular polarizations have been confirmed. The effect of the feed line on the circular polarization characteristics (axial ratio) has been studied.
An interactive fuzzy satisficing method for multiobjective nonlinear programming problems with fuzzy parameters
Authors: Sakawa Masatoshi , Yano Hitoshi
Published: July 2007

The fuzziness induced in the decision making in the actual system in general, comprises fuzziness in the formulation of the problem and that in the judgments of the decision maker (DM) as a human being. This paper proposes an interactive fuzzy satisficing method, which takes into consideration the fuzziness in problem formulation as well as that in the judgments of DM. The multiobjective nonlinear programming problem containing fuzzy parameters is transformed into the α ‐multiobjective nonlinear programming problem. After determining the fuzzy goal of DM for each objective function by eliciting the membership function, the following reference values are set: the fuzziness index α of DM for the fuzzy parameter; and the reference membership values, which are reference for the membership functions. For the specified α and the reference membership values, the corresponding augmented minimax problem is solved, and DM is supplied with the α‐Pareto optimal, together with the trade‐off ratios among membership functions and the trade‐off ratios between α and the membership functions. Obtaining the result, the DM takes the information concerning current α‐Pareto optimal solution and the trade‐off ratios into consideration, and respond by updating the reference membership values and the value of α if necessary. In this way the satisficing solution finally is derived for DM, thereby ensuring the α‐Pareto optimality. This is the proposed interactive fuzzy satisficing method. The interactive process is demonstrated for a numerical example by the interactive computer program.
A signal‐flow graph representation for switched‐capacitor networks and its application to SC circuit design
Authors: Kaneko Mineo , Onoda Mahoki
Published: July 2007

The n‐phase switched‐capacitor (SC) circuit operates by taking successively connection configurations. Consequently, even if the same edge voltage is considered, it takes n different kinds of voltages in general in a period. This makes it difficult to describe the operation of the SC circuit. Although several methods have already been proposed for representing the operation of the SC circuit, the representation by equivalent active RC circuit, which is presently used most widely, cannot provide a clear‐cut description of this essential point. From such a viewpoint, this paper first derives the primitive signal‐flow graph (SFG) representation for adequate representation of the SC circuit, which is formulated based on the common tree in the SC circuit. Then the simplified SFG representation is derived which is obtained by simplifying the representation, eliminating the cotree‐edge variables from the primitive SFG representation. The simplified SFG representation is a network representation, in which only the tree‐edge voltage and the tree‐edge stored‐charge in each phase are used as the variable‐node. It can adequately provide an intuitively clear representation of the relation between the variables in each phase and the relation between the timing of the switch connection and the operation of the circuit. The condition for the structure of SFG is derived, which corresponds to Hasler's structure condition in order that the stray capacitance does not affect the operation. By this method, the problem of constructing an SC circuit insensitive to the stray capacitance is reduced to the problem of constructing an SFG satisfying a certain condition.
A consideration in wave optics on the partial reflected wave by a Gaussian beam propagating through a square‐law medium
Authors: Kozaki Shogo , Ohki Makoto
Published: July 2007

This paper describes the numerical results and derivation of the partial reflected waves from a square‐law medium in which a Gaussian beam is incident. First the WKB solution for the wave equation in the square‐law medium is presented along with approximate solution for the first, second and third reflected waves. The investigated partial reflected waves can not be found by means of the WKB solution. An approximate expression for the partial reflected waves between two reflected beams is derived by Bremmer series. It is found that the partial reflected waves do not depend on the spot size of the beam and are basically proportional to the gradient of the permittivity. The theoretical results are in good agreement with the experimental results.
A formula for mean queue length of GI1 GI2/GI1 GI2/1 preemptive‐resume priority queues
Authors: Takahashi Haruhisa , Akimaru Haruo
Published: July 2007

It is difficult to perform a strict analysis for the GI1GI2/G1G2 single‐device preemptive‐resume priority queue, in which the arrival follows the renewal process and the processing time follows the general distribution. This paper discusses this kind of system and proposes a simple and accurate approximation for the mean queue length which coincides with the strict solution when the arrival is a Poisson process. The proposed approximation is derived by the moment analysis based on the two‐dimensional jump‐diffusion approximation. Furthermore, the diffusion coefficient is corrected based on the Pollaczek‐Khinchin formula for the M/G/1 queue system to improve the accuracy of approximation. The formula is extended to the case of n‐class priority customers. Although the proposed approximation is essentially for the heavy traffic situation, by comparing the result with the strict solutions for GI M/M1M2/1 system and simulations it is shown that the approximation has a sufficient accuracy also for medium and light traffic situations. The result is also compared with other approximations for M GI/G1G2/1 and GI1GI2/G1G2/1 systems, and it is indicated that the proposed approximation has a better accuracy than the past approximations.
Folded antenna loaded with a dipole for circular polarization
Authors: Nakamura Takashi , Abeta Takehiro , Yokokawa Senji
Published: July 2007

Analysis and design of a circularly polarized antenna made of a folded antenna loaded orthogonally with a dipole of an appropriate length is presented here. This antenna is developed in recognition that a folded antenna includes the characteristics of a transmission line. It is a simple single‐feed antenna without a power divider and a phase shifter commonly used in a conventional crossed‐dipole antenna. Making use of the fact that the current distribution can be decomposed into the balanced and unbalanced modes, one can derive the equivalent circuit and the equivalent crossed dipoles of the present antenna. The circular polarization condition is derived on effective lengths and impedances of dipoles. Based on investigation of this condition, a circularly polarized antenna has actually been designed and the characteristics of axial ratio and radiation pattern have been obtained. It is found that this antenna has few structural restrictions. Among them, element length is somewhat arbitrary. Validity of the theoretical results has been experimentally confirmed.
An IIR‐type echo canceller using a two‐channel lattice filter
Authors: Kurosawa Kaoru , Chao Jinhui , Tsujii Shigeo
Published: July 2007

In echo cancellation, the length of impulse response of an echo path to be estimated exceeds a few thousand. Therefore, instead of conventional FIR‐type algorithms, IIR‐type adaptive algorithms which can identify it with fewer parameters is desired. In the IIR case, the stability test of the estimated transfer function is important.

This paper presents an IIR‐type identification method which utilizes a 2‐channel lattice filter. The method estimates the unknown transfer function and tests its stability with O(n) operations per iteration where n is the number of the filter coefficients. The estimated transfer function always converges to the optimum solution when the input sequences can be modeled as an autoregressive (AR) process. An optimum approximate solution of an arbitrary order less than that of the estimated system can be obtained at the same time.
Crosstalk attenuation characteristics of unshielded flat cables considering earth effect
Authors: Kuwaki Nobuo , Sato Masaji
Published: July 2007

At present, flat cables for the under‐carpet use have a shielded structure to improve crosstalk characteristics. However, unshielded cables are advantageous when a very thin structure is desired. This paper is concerned with crosstalk attenuation characteristics of unshielded flat cables laid in close proximity to the ground. In this case not only the direct crosstalk due to electrostatic and magnetic couplings between conductors but also the indirect crosstalk via a path along the line to the ground must be considered. By defining the unbalance angle θ to express the degree of impedance unbalance to the ground, the coupling impedance between the longitudinal line and the real line was calculated and formulas to calculate the impedance unbalance to ground and the indirect crosstalk attenuation were derived under the assumption of a perfect conductor for the ground. Next, using these formulas the indirect crosstalk attenuation and the impedance unbalance to ground were studied as functions of the cable structure and actual cable layout such as the pair distance and the ground separation. As the result, the indirect crosstalk can not be improved by increasing the pair distance, and the impedance unbalance to ground is approximately proportional to the crosstalk attenuation. The results obtained are useful in the crosstalk design of unshielded flat cables.
A parallel architecture for recursive least square method
Authors: Hashimoto Koichi , Kimura Hidenori
Published: July 2007

Recent developments in computer technology have enabled the real‐time treatment of signal processing with a large amount of computation which had been considered to be impossible. Moreover, with the development of LSI technology, it has become possible to speed up the execution of the algorithms by parallel computing hardware.

This paper discusses a parallel architecture for the recursive least square method of system identification fitted for VLSI. If n is the order of system to be identified, the complexity T(n) required for updating the estimate at each measurement is Ts(n) = o(n2), using a single serial processor. However, it can be reduced to Tp(n) = o(n) by using the architecture consisting of (2n + 6) elementary processors and a set of delay units. Moreover, we discuss a method to speed up p‐time updates from Ts(n, p) = o(n2p) to TM(n, p) = o(n + p) using o(np) elementary processors by vectorizing the measurements.
Performance of matched filter detection for multiphase DPSK signal in satellite‐aircraft multipath channel
Authors: Miyagaki Yoshiya , Konishi Kenichi
Published: July 2007

Data transmission between a satellite and an aircraft is investigated in the case of a multiphase DPSK system operating in the L‐band. The error rate characteristics of matched filter detection are analyzed exactly on the basis of a multipath model consisting of a direct path wave and a relatively delayed, high‐speed, diffuse‐path Rayleigh wave due to reflection at the Earth's surface. On the basis of this model, concrete error rate (Pe) computations are performed in the case of 4‐phase DPSK (symbol rate 1/Ts) as a function of the Doppler spread (BD) and average relative delay (T) of the reflected wave. Considering the influence of varying duration of the reflected wave, the results show that the error rate Pe is maximum (worst case) for BDTs ≒ 0.40 independently of the powers of the direct wave, reflected wave and noise. Furthermore, in the range BDTs ⩽ 0.17 the diffusion wave can be treated as an AC vector. Next considering the influence of the relative delay of the reflected wave, the value of Pe is given for the 16 cases of phase difference in the delay range 0 ≦ T ≦ Ts and it is shown that the effect of relative delay is negligible for T/Ts ⩽ 1/40 and that the minimum average error rate (best case) is obtained for τ/Ts ≒ 1/5.
Experiment on searching for electromagnetic wave sources by using a synthetic aperture technique
Authors: Nagasawa Yoji , Kikuchi Jun'Ichi , Sato Risaburo
Published: July 2007

To control unwanted electromagnetic waves, it is important to estimate accurately the location of the electromagnetic source nearby. Based on the synthetic aperture technique and the signal processing algorithm of the spatial Fourier transform, the location of the source within a planar space of 10 wavelength square has been performed with an electromagnetic source model. It is confirmed experimentally that a satisfactory search of the source is possible using Mills' cross method. A parallel twin wire is used as the electromagnetic source model. Different types of discontinuities are placed along the transmission line and the electromagnetic wave is forced to radiate to create a source. In practice, 300 or 400 MHz is selected and 21 measurement points are selected along the x and y axes with each half‐wavelength spacing. The error of locating the measurement points is the cause of the wave source estimation error. It is demonstrated that the algorithm used here is rather insensitive to these errors.
Reflecting characteristics of anisotropic rubber sheets and measurement of complex permittivity tensor
Authors: Hashimoto Osamu , Shimizu Yasutaka
Published: July 2007

It is well known that rubber sheets mixed with carbon particles or carbon fiber usually exhibit large surface anisotropy due to the rolling process employed in fabrication. The use of such materials for special microwave applications requires measurement of the complex permittivity tensors. However, no reliable method for this purpose in such lossy anisotropic materials has been established. In this paper the reflection loss of anisotropic sheet materials is measured and a method for obtaining complex permittivity tensors from the experimental results is given. That is, the frequency characteristics of the reflection loss are measured for various polarization directions of incident waves at the sheet materials and each element of the tensors including nondiagonal ones can be estimated by the least squares method using these data. As a result of study of the principal direction of the sheet using measured values of this tensor, it is found that the real and imaginary parts differ largely in the principal direction for some of the rubber sheets with carbon used for this measurement.
Suppression of ground clutter using an X‐band radar
Authors: Iwama Tsukasa , Sekine Matsuo , Musha Toshimitsu
Published: July 2007

Most of the clutter received by an L‐band air route surveillance radar obeys Weibull distribution with various values of the shape parameters. The L‐band radar has a frequency of 1.3 GHz and pulsewidth of 3 μs. Hence, the spatial resolution is as large as 450 m. The X‐band radar, on the other hand, ns. frequency of 9.4 GHz and pulsewidth of 80 ns. The spatial resolution is as small as 12 m; we have found that the clutter amplitude distribution obeys a composite Weibull distribution when reflectors are ordinary terrain and such structures as buildings. Clutter suppression techniques for Weibull and non‐Weibull echos are proposed.
The optimum interpolatory approximation of waves using time limited interpolation functions
Authors: Kida Takuro
Published: July 2007

An investigation has been conducted about the interpolatory approximation of waveforms using a set of sample points in the form of groups of K generally non‐equidistant sample points which are arranged periodically over a time axis. First, we consider a set Γ of waveforms f(t) whose Fourier spectra F(ω) are bandwidth limited in |ω| ≤ ω1 and which satisfy \documentclass{article}\pagestyle{empty}\begin{document}$ \int\limits_{ - w_1 }^{w_1 } {|F(w)|^2 } /W(w)dw \le A(> 0) $\end{document} for some positive weight W(ω). The interpolation function, which minimizes the supremum of the absolute error between the original waveforms f(t) and the corresponding approximation waveforms over Γ, is derived. Here the approximate waveforms are taken to be the total sum of the values at the sample points mentioned above multiplied by the interpolation functions time‐limited to a finite time‐band centering at the corresponding sample points. A choice of time limitation of the interpolation function discussed above is fundamental for realization of interpolation functions by a FIR filter. If displacement along the time axis is ignored, the optimal interpolation functions mentioned above are divided into K groups and it is shown that they satisfy the orthogonality for a finite sum. Next, using the concept of an inner product expression of a quasi‐bilinear form, an extension of the above concept is made and the optimal interpolation function is derived. The extension includes a case in which sample values contain statistical errors and a case in which the original wave is reproduced using sample values of linearly transformed waveforms.