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Interactive analysis of propagation in optical fibers

computer Applications in Engineering Education 1993年第3期1卷 197-197页

作者： Aicklen, G.H. Tamil, L.S. Erik Jonsson School of Engineering and Computer Science and Center for Applied Optics The University of Texas at Dallas Richardson 75080 Prior to returning to graduate study in 1987 Mr. Aicklen had industrial experience with the Defense Systems and Electronics Group at Texas Instruments in Dallas. In 1985 he left Texas Instruments to pursue a private venture. In 1987 he joined the staff of The University of Texas at Dallas as a research associate in the Erik Jonsson School of Engineering and Computer Science. Mr. Aicklen's research interests include fiber optics nonlinear guided wave optics integrated optical devices and numerical methods in optics. Dr. Tamil is a member of Sigma Xi Optical Society of America Electromagnetics Academy and is a elected member of Commission B and D of the International Union of Radio Science.

We have developed a set of computer codes that compute the propagation constants and field patterns for the propagating modes of cylindrical optical fibers. From a simple set of finite difference equations, solutions of the scalar Helmholtz wave-equation may be computed across a range of normalized frequencies to generate curves describing the dispersion characteristics of the fiber. Accurate cutoff frequencies for any mode can also be computed. We designed the computer codes around α-index profiles since these profiles have been extensively covered in the literature, but our system also supports arbitrary profiles within the limits of the “small index gradient” and “weakly guiding” approximations. The computer codes are accurate and fast. They may be used interactively to explore dispersion in optical fibers and the effects of finite cladding width on dispersion.

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Interactive tools for signal processing education. The signal processing instructional facility (SPIF lab) at Washington State University

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computer Applications in Engineering Education 1993年第6期1卷 517-517页

作者： Bamberger, R.H. Signal Processing Instructional Facility School of Electrical Engineering and Computer Science Washington State University Pullman WA 99164-2752 Dr. Roberto H. Bamberger:was born on January 30 1965 in Buenos Aires Argentina. He received his B.E.E and PhD from the Georgia Institute of Technology in 1986 and 1990 respectively. Currently Dr. Bamberger is an assistant professor in the School of Electrical Engineering and Computer Science at Washington State University. Dr. Bamberger's research program is focused on the design implementation and application of multidimensional multirate filter banks subband image and video compression analysis of nonstationary data and application of digital signal processing techniques in the design of analog and mixed-mode integrated circuits. Dr. Bamberger is the founder and director of the Signal Processing Instructional Facility (SPIF Lab) at Washington State University. The SPIF Lab features interactive multimedia-based tools for teaching concepts related to linear systems theory. Dr. Bamberger is active in developing multimedia-based instructional laboratories for a variety of other topics as well. In addition to his teaching and research programs Dr. Bamberger is an associate editor for theIEEE Transactions on Signal Processingand a member of the editorial board forComputer Applications in Engineering Education. Dr. Bamberger is also advisor to the WSU Student Branch of the IEEE and assistant director of the WSU Cougar Marching Band. Dr. Bamberger is a member of Phi Eta Sigma Eta Kappa Nu Tau Beta Pi and Kappa Kappa Psi.

The Signal Processing Instructional Facility (SPIF Lab) is an experiment in using in interactive multimedia for teaching concepts related to linear systems theory and signal processing. The goals of the SPIF lab are to augment, enhance, and interconnect sophomore, junior, and senior level courses with the common thread of linear systems and transforms by unifying the experimentation medium. In this fashion, physical phenomenon is returned to the forefront of engineering education. The laboratory features powerful Mathematica Notebooks (a form of hypertext) and interactive applications that use dedicated DSP microprocessors.

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A new method for the study of hazard and the uses of it

A new method for the study of hazard and the uses of it

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1992 Singapore: Communications on the Move, ICCS/ISITA 1992

作者： Nicolas, Galupa Teaching Assistant of Computer Science Polytechnic Institute of Iasi Department of Computer Science Romania

ISBN: (纸本)0780308034

The present paper tries to consider the problem of hazard in digital structures. The first stage to be achieved is a rigorous analysis of hazard in combinatorial logic circuits already existing, and whose physical implementation is well known to us. The analysis method that we suggest is developed on the scheme of the time constants method. The second stage to be passed consists of studies on the functioning of a finite automaton.. We remind that we define the automaton in a Mealy meaning being the quintuple (X,Y,Z,F,G) where X is the finite array of the input variables, V is the finite array of the state variables, Z is the finite array of the output variables, F: X × Y -> Y the transfer function (towards state) and G X × Y -> Z the output function, mentioning that F, G represent groups of functions. © 1992 IEEE.

关键词： Hazards

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Customer waiting times in an (R,S) inventory system with compound Poisson demand

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ZOR Zeitschrift für Operations Research methods and Models of Operations Research 1992年第4期36卷 315-332页

作者： van der Heijden, M.C. De Kok, A.G. Centre for Quantitative Methods AK Eindhoven 5600 P.O.Box 414 Netherlands Dept. of Mathematics and Computer Science Eindhoven University of Technology MB Eindhoven 5600 P.O.Box 513 Netherlands

Besides service level and mean physical stock, customer waiting time is an important performance characteristic for an inventory system. In this paper we discuss the calculation of this waiting time in case a periodic review control policy with order-up-to-level S is used and customers arrive according to a Poisson process. For the case of Gamma distributed demand per customer, we obtain (approximate) expressions for the waiting time characteristics. The approach clearly differs from the traditional approaches. It can also be used to obtain other performance characteristics such as the mean physical stock and the service level. © 1992 Physica-Verlag.

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Nondifferentiable design optimization problems with application to control engineering

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Optimization 1992年第1期25卷 83-90页

作者： Venkov, G.I. Krushev, N.I. Technical University of Sofia Dept. of Numerical Methods and Analysis Institute of Applied Mathematics and Computer Science Bulgaria

The problems and algorithms in question are applied to the parameter design of automatic control systems. The generality of (1-1) permits the definition of a wide range of constraints in the time and frequency domains, as well as on the eigenvalues and singular values of the system matrices. The designer can set up and satisfy direct requirements to the form of the output reaction, the locus of the return difference, the frequency characteristics, the degree of stability etc. Examples and graphics illustrate the characteristic features of the methods discussed. The algorithms are implemented in a software system for vector optimization developed by the authors. © 1992 Gordon and Breach science Publishers S.A.

关键词： control engineering design optimization Non-differentiable optimization

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COMPARISON OF DOWNHOLE AND SURFACE SAMPLING FOR THE DETERMINATION OF VOLATILE ORGANIC-COMPOUNDS (VOCS) IN GROUND-WATER

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GROUND WATER MONITORING AND REMEDIATION 1992年第1期12卷 126-133页

作者： ROSEN, ME PANKOW, JF GIBS, J IMBRIGIOTTA, TE Michael E. Rosen received his B.A. in chemistry from the State University of New York at Binghamton in 1981 and a Ph.D. in environmental science and engineering from the Oregon Graduate Institute in 1988. His research interests include trace environmental analysis of organic compounds. He is now manager of the Voluntary Cleanup Section of the Oregon Department of Environmental Quality (Environmental Cleanup Division 811 S.W. 6th Ave. Portland OR 97204) where he is working to develop streamlined procedures and processes for the investigation and cleanup of hazardous substance sites. James F. Pankow is professor and chairman of the Department of Environmental Science and Engineering at the Oregon Graduate Institute (Oregon Graduate Institute of Science and Technology Department of Environmental Science and Engineering 19600 N.W. von Neumann Dr. Beaverton OR 97006–1999). He received his B.A. in chemistry in 1973 from the State University of New York in Binghamton and his Ph.D. in environmental engineering science from the California Institute of Technology in Pasadena California in 1979. His group is involved in the study of the physical and chemical processes affecting the behavior of organic and inorganic chemicals in the environment. This work includes the development and application of sensitive analytical methods for the determination of trace organic contaminants in ground water systems. Jacob Gibs is an environmental engineer with the U.S. Geological Survey Water Resources Division (810 Bear Tavern Rd. Ste. 207 West Trenton NJ 08628). He received a B.S. in mechanical engineering in 1968 an M.S. in environmental engineering in 1975 and a Ph.D. in environmental engineering in 1983 all from Drexel University Philadelphia Pennsylvania. He is currently project chief of a study on representative sampling of ground water for trace levels of organic compounds. His research interests include evaluating ground water sampling techniques and devices for purgeable organic compounds design of sampling

The relative precision and accuracy of sampling and analysis methods for the determination of trace concentrations of volatile organic compounds (VOCs) in ground water were compared. Samples were collected from a well containing nanogram-per-liter (ng/L) to microgram-per-liter (mu-g/L) levels of VOCs. A Keck helical rotor submersible pump was used to collect samples at the surface for analysis by purge and trap (P&T) and for analysis by adsorption/thermal desorption (ATD). Downhole samples were collected by passing water through an ATD cartridge. Although slight spontaneous bubble outgassing occurred when the water was brought to the surface, the relative precisions and comparabilities of the surface and downhole methods were generally found to be equivalent from a statistical point of view. A main conclusion of this study is that bringing sample water to the surface for placement in VOC vials (and subsequent analysis by P&T) can be done reliably under many circumstances. However, care must still be taken to prevent adsorption losses and cross contamination. Samples subject to strong bubble outgassing will need to be handled in a special fashion (e.g., by downhole ATD) to minimize volatilization losses. Additionally, the higher sensitivity of the ATD method allows lower detection limits than are possible with P&T. For example, several compounds present at the ng/L level could be determined with confidence by ATD, but not by P&T.

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AN AI-BASED DECISION SUPPORT SYSTEM FOR NAVAL SHIP DESIGN

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NAVAL ENGINEERS JOURNAL 1992年第3期104卷 156-165页

作者： CHOU, YC BENJAMIN, CO Yu-Chao Chou:has served as an engineering officer in the Republic of China Navy for 20 years. He graduated from the Chung Chen Institute of Technology in 1972 with a bachelor of science degree in naval architecture. He received a master of engineering degree in naval architecture and marine engineering from the University of Michigan in 1977. He obtained his Ph.D. in engineering management at the University of Missouri-Rolla in 1991. His current research interests include artificial intelligence project management and concurrent engineering. He is a member of the American Society of Naval Engineers and the Institute of Industrial Engineers. Colin O. Benjamin:is an associate professor of engineering management at the University of Missouri-Rolla and has had several years of international teaching industrial and consulting experience. He received a Ph.D. in industrial engineering from the University of the West Indies an MBA from the Cranfield Institute of Technology U.K. and an M.Sc. in engineering production and management from the University of Birmingham U.K. His current research interests include artificial intelligence (AI) multi-criteria decision making (MCDM) facilities planning and computer integrated manufacturing (CIM). He is a Senior Member of the Institute of Industrial Engineers and the Society of Manufacturing Engineers.

Naval ship design is a complex, iterative decision-making process that requires not only qualitative reasoning and quantitative computations, but also effective handling of massive amounts of information. The development of a systematic procedure in the form of an interactive Decision Support System (DSS) incorporating artificial intelligence (AI) techniques can assist in improving the design process. The DSS reported in this paper integrates conventional naval ship design application software with an expert system. Modeling techniques such as a spreadsheet, a database management system, and graphic display capability are incorporated as well. This DSS facilitates "what-if" analysis of design problems and assessment of the trade-offs between performance and cost. The DSS will aid rapid generation of design alternatives and facilitate their evaluation. A final recommendation is made based on multiattribute decision analysis using the straightforward points allocation method and the analytic hierarchy process. During a typical consultation process, the user is prompted for inputs to the naval ship design process and is provided with a wide range of reports in graphical and numerical form. During a structured system evaluation, the DSS displayed considerable accuracy, flexibility, speed, user-friendliness, and cost-effectiveness. The reliability and validity of the system were also confirmed. These evaluation procedures provide a replicable methodology for verification and validation of this type of AI-based decision support system.

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An abstract approach to VLSI test

An abstract approach to VLSI test

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1991 IEE Colloquium on Design for Testability (Digest No. 1991/102)

作者： M. Stannett Formal Methods Group Department of Computer Science Sheffield University UK

Inherent imperfections in the VLSI fabrication processes mean that even logically correct designs may be fabricated as faulty chips. Testing of devices is therefore essential. The author considers the use of CCS to deduce testability features of VLSI. He shows first that a natural correspondence exists between circuit designs and a certain class of processes in CCS (a popular abstract language for reasoning about concurrent systems), and then use this correspondence to show how standard faults can economically be represented, and reasoned about. Questions considered include: given such and such a fault, when can it be detected? If a fault is detectable, to what extent can its location be identified? And given a design, can one construct a logically equivalent process of improved testability?.< >

关键词： Automatic test equipment Digital integrated circuits Integrated circuit testing Design automation Manufacturing testing Very-large-scale integration

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Domain reduction dependencies: A new type of dependency for statistical database security

Domain reduction dependencies: A new type of dependency for ...

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Annual computer Security Applications Conference

作者： S.C. Hansen E.A. Unger Quantitative Methods/Computer Science University of Saint Thomas Saint Paul MN USA Computing and Information Sciences Kansas State University Manhattan KS USA

A new type of data dependency, the domain reduction dependency is defined. Given a set of attributes over which a query is being made, this dependency allows one to more accurately predict the probability of release of sensitive statistics for that query than could have been done with table size alone. In addition, the properties of DRDs provide metainformation on the gain and loss of information within a lattice of queries through the addition or removal of attributes from a query set. This increased formalism on information loss and gain may provide insights which will allow the construction of better techniques for protecting the security of future statistical databases.< >

关键词： Databases Data security Statistics Lattices Information security computer security Level control Probability Protection computer science

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ADAPTING AVAILABLE FINITE-ELEMENT STRUCTURAL PROGRAMS TO SOLVE 3-DIMENSIONAL HIGH-FREQUENCY ELECTROMAGNETIC PROBLEMS

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INTERNATIONAL JOURNAL OF MICROWAVE AND MILLIMETER-WAVE computer-AIDED ENGINEERING 1991年第4期1卷 386-394页

作者： NAVARRO, EA FEMENIA, JM SUCH, V Departamento de Fisica Aplicada Universitat de València C Doctor Moliner 50.46100 Burjassot (València) Spain Enrique A. Navarro was born in Sueca (Valéncia) Spain on January 18 1965. He received the Licenciado degree in Physics from the Universitat de Valéncia Spain in 1988. After working on Systems Simulation at GMV S.A. Madrid. Spain. he returned to the Universitat de Valéncia in 1980 where he began to study for the PhD degree in the Department de Fésica Aplicada. Universitat de Valéncia Spain. He is currently Assistant Professor in the Department of Applied Physics. His rescarch interests are in the area of microwave engineering and numerical method for solving electromagnetic wave propagation problems. Jose M. Femenia was born in Segorbe (Castellón) Spain in 1962. He obtained in Physics from the the Licenciado degree in Physics from the Universitat de Valéncia Spain in 1987 Universitat. After working in Laser and Optical Technology in the Department d'Optica di la Universitat de Valéncia he received a grant to work in numerical techniques for electromagnetics in the Departnment de Fisica Aplicada. He currently works in Computer Science and Communications in the Servei d'lnformàtica de la Universitat de Valéncia. Vicente Such was born in Valéncia Spain on August 10 1943. He received the Licenciado degree in Physics in 1967 and the PhD degree in 1971 both from the Universitat de Valéncia Spain. From 1967 to 1974 he was Assistant Professor with the Department of Electricity and Magnetism Universitat de Valéncia and with the Universitat Politécnica de Valkncia. From1974 to 1981 he was Professor of Electricity and Magnetism at the Universitat de Extremadura Universitat de Valéncia and Universidad de Palma de Mallorca Spain. He is now a Professor in the Department of Applied Physics at Universitat de Valéncia. His current research interests deal with microstrip antennas arrays Microwave passsive circuits and computer methods in electromagnetics.

The adaptation of available structural mechanics software to solve microwave problems is possible by the analogy between the differential equations. A brief review of the analogy between transverse or shear waves in elasticity and electromagnetic waves is presented, followed by a more detailed discussion of the adaptation of a program to obtain the resonant frequencies of a rectangular resonant cavity, doing a three-dimensional analysis. The geometry of the electric field is also obtained for the resonant modes.

关键词： Microwaves

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