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A study on degradation of spatial resolution in frequency-modulated continuous wave reflectometry due to nonlinear optical frequency sweep

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eLeCTRONICS AND COMMUNICATIONS IN JAPAN PART II-eLeCTRONICS 1995年第10期78卷 28-35页

作者： Wang, LT Iiyama, K Hayashi, K Faculty of Technology Kanazawa University Kanazawa Japan 920 Koichi liyama:received his B.E. M.E. and Dr. of Eng. degrees in Electronic Engineering all from Kanazawa University Kanazawa Japan in 1985 1987 and 1993 respectively. From 1987 to 1988 he worked at Yokogawa Hewlett-Packard Ltd. Since 1988 he has been working as a Research Associate in the Department of Electrical and Computer Engineering Kanazawa University and is now a Lecturer. His current research interest is fiber-optic sensors optical fiber science including Er-doped fibers optical waveguides and the optical reflectometry. Dr. liyama is a member of the IEEE and the Japan Society of Applied Physics. Members Ken-ichi Hayashi:received his B.E. degree in Electronic Engineering from Kanazawa University Kanazawa Japan in 1966 and his Dr. of Eng. degree from Nagoya University Nagoya Japan in 1977. Since 1966 he has been with the Department of Electronics Kanazawa University where he is now a Professor in the Department of Electrical and Computer Engineering. He is currently engaged in research on applications of Er-doped optical fibers fiber-optic sensors optical waveguides and optical reflectometry. Dr. Hayashi is a member of the SICE and the IEEE.

The degradation of the spatial resolution in frequency-modulated continuous wave (FMCW) reflectometry due to the nonlinearity in the optical frequency sweep are discussed both experimentally and theoretically. The response lag in the optical frequency change of a laser diode behind the injection current change was experimentally measured, showing that there were several time constants in the optical frequency response. The interference signals in the FMCW reflectometry were theoretically calculated by taking account of the response lag. From these calculations, the beat frequency becomes low just after the turning point of the optical frequency sweep;this is due to the response lag in the optical frequency response. As a result, the spectrum of the interference signal is spread out toward the low frequency region and spatial resolution is degraded. Moreover, the spatial resolution is seriously degraded with increasing the diagnosing distance due to the nonlinearity in the optical frequency sweep. The calculated results agree well with the measured results.

关键词： laser diode optical frequency sweep modulation reflectometry

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Method for distance estimation of single‐phase‐to‐ground faults in electrical distribution networks with an isolated or compensated neutral

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european Transactions on electrical Power 1995年第3期5卷 193-198页

作者： Lehtonen, M. Matti Lehtonen (1959) received his degrees of Master of Science and Licenciate of Technology both in electrical engineering from the Helsinki University of Technology Helsinki/Finland in 1984 and 1989 respectively. From 1984 to 1987 he was with the Consulting Company Ekono planning industrial power systems and developing computer-aided design systems. Since 1987 he has been with Technical Research Centre of Finland. His main areas of interest are harmonics reactive power compensation ground-fault protection and automation in electrical distribution networks. (Technical Research Centre of Finland Otakaari 7 B SF-02150 E s p Finland T +35 80/4566455 Fax +35 80145665 38)

The paper discusses how current and voltage measurements derived from the substation can be used for single‐phase‐to‐ground fault location in medium‐voltage distribution lines. The networks considered are assumed to be radially operated with either an isolated or compensated neutral. In these networks the fundamental frequency ground fault currents usually are so small that no reasonab.e fault‐distance estimate can be based on them. A possib.e solution is the utilisation of ground‐fault initial transients. In this paper a method for ground‐fault distance estimation, based on the least squares estimation of transient parameters, is presented. Copyright © 1995 John Wiley & Sons, Ltd.

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ISDN LOOP eXTeNSION USING A MID-SPAN AMPLIFIeR

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INTeRNATIONAL JOURNAL OF COMMUNICATION SYSTeMS 1995年第3期8卷 219-224页

作者： eRKeR, GJ DODDS, De KRZYMIeN, WA David E. Dodds was born in Saskatoon Canada in 1945. He received the B. Eng. and MSc. degrees from the University of Saskatchewan in 1966 and 1968 respectively. He worked with Bell Northern Research (Ottawa) on PBX design in 1969 1972 and 1978. Since 1969 he has been with the University of Saskatchewan where he is currently Professor of Electrical Engineering. He teaches courses in electronics and communications and also presents short courses on the fundamentals of telephony. Current research interests are in data transmission signal processing architecture and frame synchronization for PCM and spread spectrum systems. He has been granted five patents relating to commercial products in delta-modulation telephone line interfacing and computer data transmission. In 1986 he was on sabbatical leave at BNR Inc. and worked with an ANSI committee on the standardization of FDDI-II a combined voice and data system. Mr. Dodds is a Registered Consulting Engineer in Saskatchewan. Witold A. Krzyden received his MSc. (Eng.) and Ph.D. degrees (both in Electrical Engineering) in 1970 and 1978 respectively from the Poznan Technical University in Poznan Poland. He was awarded the Minister's of Science and Technology Prize of Excellence for his Ph.D. thesis. From 1970 to 1978 he was a Research Engineer and Teaching Assistant and then from 1978 to 1980 an Assistant Professor of Electrical Engineering at the Poznan Technical University. In 1980 he won a Dutch Government Research Fellowship at the Twente University of Technology in Enschede the Netherlands for the year of 1980/1981. In the following year of 1981/82 he was a Research Assistant Professor there. From 1982 to 1986 he was an Assistant Professor of Electrical Engineering at Lakehead University in Thunder Bay Ontario Canada. In 1986 he joined the Univeristy of Alberta and Alberta Telecommunications Research Centre (now Telecommunications Research Laboratories or TRLabs) as an Associate Professor of Electrical Engineering. Currently he is a Professor of E

The 5.5 km range of the basic rate ISDN loop has b.en extended by using a negative impedance amplifier and by using a 2 wire/4 wire (2w/4w) amplifier. The negative impedance amplifier extends the range of the loop by 1.0 km, whereas the 2w/4w amplifier extends the range by 1.5 km at the expense of increased complexity. As part of the amplifer design, a resistor/capacitor network has b.en developed which closely matches the characteristic impedance of telephone cab.e. error rate tests have b.en conducted using various lengths of cab.e and an operating ISDN line.

关键词： ISDN PHYSICAL LAYeR bASIC RATe LOOP RANGe eXTeNSION

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Numerical validation method for nonlinear equations using interval analysis and rational arithmetic

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eLeCTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMeNTAL eLeCTRONIC science 1995年第7期78卷 99-112页

作者： Kashiwagi, M Oishi, S School of Science and Engineering Waseda University Tokyo Japan 169 Members Shin'ichi Oishi received his B.E. and Dr. of Eng. degrees in 1976 and 1981 respectively from Waseda University. Since 1980 he has been affiliated with Waseda University and ispresently Professor in the Department of Inf. Sch. Sci. Eng. He was a Visiting Researcher from March 1987 to March 1988 at the University of California Berkeley. He is engagedin research on mathematical information engineering focusing on nonlinear systems. He received the Paper Award in 1991. This paper proposes an algorithm with a guaranteed accuracy for the finite-dimensional nonlinear equation. First an algorithm is shown which can determine the interval containing the true solution based on the given approximiate solution. the method is based on the interval analysis and considers the representation error of the equation. Then the interval iteration method is shown which can arbitrarily reduce the interval. the rational number arithmetic is used and the rounding of the rational number is utilized effectively. Finally an experimental implementation of the algorithm on a computer is presented together with some numerical examples.

This paper proposes an algorithm with a guaranteed accuracy for the finite-dimensional nonlinear equation. First, an algorithm is shown which can determine the interval containing the true solution, based on the given approximate solution. The method is based on the interval analysis and considers the representation error of the equation. Then the interval iteration method is shown which can arbitrarily reduce the interval. The rational number arithmetic is used and the rounding of the rational number is utilized effectively. Finally, an experimental implementation of the algorithm on a computer is presented, together with some numerical examples.

关键词： numerical validation interval analysis rational arithmetic Krawczyk's interval function nonlinear equation

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Virtual hand tool with force feedback 94

Virtual hand tool with force feedback

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Conference on Human Factors in Computing Systems, CHI 1994

作者： balakrishnant, Ravin Ware, Colin Smith, Tim Faculty of Computer Science University of New Brunswick P.O. Box 4400 FrederictonNBE3B 5A3 Canada Dept. of Mechanical Engineering University of New Brunswick P.O. Box 4400 FrederictonNBE3B 5A3 Canada

ISBN: (纸本)0897916514

We present a system which simulates working with a hand held machine tool on a piece of soft material. A two degree-of-freedom force reflecting joystick allows the user to feel the reactive forces between the virtual toolbit and material. An experiment to investigate the effects on performance in a high precision task when the standard visual display is augmented by our force display system shows a 44% (p © 1994 ACM.

关键词： Degrees of freedom (mechanics)

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Analysis of the effect of size of omega network on its fault tolerance behaviour in presence of multiple faults

Analysis of the effect of size of omega network on its fault...

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Ieee Region 10 International Conference TeNCON

作者： S. Das K. Chaudhuri Departmentt. of Computer Science & Technology B.E. College (D.U.) Howrah India Departmentt of Computer Science & Engineering Jadavpur University Calcutta India

The paper deals with comprehensive treatment of the fault tolerant characteristics of a class of nonredundant multistage interconnection network. The ob.ervations and results presented are around omega networks, as a representative member of the class of topologically equivalent nonredundant multistage interconnection network. As fault model, the paper considers that the multiple switching element fault may be in the same stage or in different stages. Several relations and expressions on different parameters and size of the network are derived to estimate the behaviour of the network of different spread towards variety of fault distribution.< >

关键词： Fault tolerance Intelligent networks Redundancy Fault detection Switches Costs Network topology Multiprocessor interconnection networks

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electron and hole real space transfer in InAlAs/InGaAs heterostructure device 24

Electron and hole real space transfer in InAlAs/InGaAs heter...

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24th european Solid State Device Research Conference, eSSDeRC 1994

作者： berthold, G. Mastrapasqua, M. Canali, C. Manfredi, M. Zanoni, e. bahl, S.R. Del Alamo, J.A. Dipartimento di Elettronica e Informatica Via Gradenigo 6A Padova35131 Italy AT and T Bell Laboraties Muray HillNJ07974 United States Dipartimento di Scienze Dell' Ingegneria Via Campi 213/B Modena41100 Italy Dipartimento di Fisica Viale delle Scienze Parma43100 Italy Department of Electrical Engineering and Computer Science MIT CambrigeMA02139 United States

ISBN: (纸本)2863321579

We report a detailed experimental analysis of both electron and hole Real Space Transfer occurring in InAlAs/InGaAs heterostructure devices grown on InP. At high drain-source voltages electrons are heated and holes are created by impact ionization. both electrons and holes contribute to the gate current whereas the relative size of these contribution depends on the magnitude and polarity of the bias applied to the control and to the drain electrode. © 1994 editions Frontieres.

关键词： Impact ionization

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NUMeRICAL-MeTHOD FOR CALCULATING SURFACe CURReNT-DeNSITY ON 3-DIMeNSIONAL SMOOTH SCATTeReRS

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eLeCTRONICS AND COMMUNICATIONS IN JAPAN PART II-eLeCTRONICS 1994年第2期77卷 1-11页

作者： IKUNO, H GONDO, M NISHIMOTO, M Faculty of Engineering Kumamoto University Kumamoto Japan 860 Himyoshi Ikmo received his B.E. M.E. and Ph.D. from Kyushu University in 1962 1964 and 1979 respectively. From 1967 to 1970 he was a Research Associate in Computer Science and Communication Engineering at Kyushu University. He joined the Department of Electrical Engineering and Computer Science of Kumamoto University in 1970 and is currently a Professor there. During 1983 to 1984 he was a Visiting Professor at the Polytechnic University Brooklyn NY. His research interests are in the areas of scattering diffraction and wave propagation in the theory of electromagnetics. Dr. Ikuno is a member of IEEE and IEE of Japan. Michim Gondo graduated from National Defense Academy Yokosuka in 1985 and received his M.E. from Kumamoto University in 1990. He is currently in the doctoral program at Kumamoto University. His research interest is in three-dimensional electromagnetic scattering. Masahiko Nkhimoto received his B.S. in Electronic Engineering from Kumamoto University in 1982 and an M.S. and Ph.D. from Kyushu University in 1984 and 1987 respectively. Since 1987 he has been a Research Associate in the Department of Electrical Engineering and Computer Science Kurnamoto University. His research interests are in the areas of scattering and diffraction of electromagnetic waves.

This paper shows that the surface current density can be calculated by using approximate total tangent magnetic vector fields which are expressed by finite number of linear combination of tangent vectors of spherical wave functions. Sampling points are determined by considering the property of associated Legendre functions and trigonometrical functions. by setting a number of sampling points to twice the largest mode number, a computer-aided algorithm is obtained. The accuracy of the solutions is checked and the polarization dependence of the surface current densities is clarified.

关键词： YASUURA MeTHOD 3-DIMeNSIONAL PROb.eM bODY OF ReVOLUTION LeAST-SQUAReS PROb.eM

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3-D eDGe eLeMeNT ANALYSIS OF DIeLeCTRIC-LOADeD ReSONANT CAVITIeS

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INTeRNATIONAL JOURNAL OF NUMeRICAL MODeLLING-eLeCTRONIC NeTWORKS DeVICeS AND FIeLDS 1994年第1期7卷 35-41页

作者： ZHU, ZL DAVIeS, Jb FeRNANDeZ, FA Department of Electronic and Electrical Engineering University College London WC1E 7JE U.K. On leave from the Department of Radio Electronics Peking University Beijing 100871 People's Republic of China. Le-zhu Zhou was born in Guizhou China in 1944. He received the B.S. degree in Physics and M.S. degree in Electronics from Peking University Beijing China in 1968 and 1981 respectively. Since 1981 he has been on the staff of the Department of Radio-Electronics of Peking University. In 1983 he was appointed as a Lecturer. In 1989 he became an Associate Professor. Since September 1991 he has been doing research as an Academic Visitor at the Department of Electronic and Electrical Engineering of University College London. He has been engaged in the electromagnetic field theory and its application. Recently his research interest has been in the computer modelling of optical and microwave structures by using edge element methods. J. Brian Davies was born in Liverpool England in 1932. He received the B.A. degree in mathematics in 1955 from Jesus College Cambridge England. He received the M.Sc. degree in mathematics the Ph.D. degree in mathematical physics and the D.Sc. (Eng) degree in engineering in 1957 1960 and 1980 respectively from the University of London England. From 1955 to 1963 he worked at the Mullard Research Laboratories Salford Surrey England except for two years spent at University College London. In 1963 he joined the academic staff of the Department of Electrical Engineering University of Sheffield England. Since 1967 he has been on the staff at University College London where he is now Professor of Electrical Engineering. From 1971 to 1972 he was Visiting Scientist at the National Bureau of Standards Boulder CO. In 1983 he was a Visitor at the Department of Engineering Science University of Oxford England. From 1988 to 1989 he was a Visiting Professor at the University of Colorado Boulder CO. His research interests have included microwave and optical aspects of electr

The eigenmodes in electromagnetic cavities, loaded with arbitrarily shaped dielectric materials, are computed by the edge element method. The computation shows that the well known 'spurious modes' no longer appear. Formulae are given and verified so that the number of zero eigenvalues, which come from del x H = 0, may be accurately predicted. Formulae for the order and density of the global matrices are given for a rectangular cavity regularly divided into bricks and tetrahedra, allowing an associated comparison between the contrasting edge and nodal element formulations. Comparison of the computed results with availab.e theoretical and previously published data show the edge element approach to be a robust, accurate and effective method.

关键词： Dielectric waveguides

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TRACING eVACUATION ROUTe USING PARALLeL ALGORITHM IN THe CASe OF FIRe IN COAL MINeS

TRACING EVACUATION ROUTE USING PARALLEL ALGORITHM IN THE CAS...

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计算机，通信，控制与电力工程国际会议

作者： Suman banerjee Sourav K Dutta Dept.of Mining Engineering B.E CollegeHowrah.India. Dept.of Computer Science & Engineering Jadavpur University

Fire in coal mines is quite common and the hazard of fire always looms *** present paper deals with the situation of accidental fire b.eaking up In a board and pillar *** board and pillar has b.en taken as a particular instance,the idea can however be applied to any working district having different method of extraction. The paper highlights the capabilities of a parallel algorithm executing in a message-passing multi-processing environment in *** idea appears to be superior to the ordinary procedural algorithm using record type data structures and employing arrays and pointers for search methods as suggested by Kozielski[1].

关键词： Coal mines Route tracing Parallel processing Transputers Real-time.

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