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A TWO-LEVEL METADATA DICTIONARY APPROACH FOR SEMANTIC QUERY PROCESSING IN MULTIDATABASE SYSTEMS

International Journal of Software engineering and Knowledge engineering 1993年第2期3卷 231-255页

作者： MIIN-JENG PAN SHI-KUO CHANG CHIEN-CHIAO YANG Department of Electronic Engineering National Taiwan Institute of Technology 43 Keelung Road Section 4 Taipei 10772 Taiwan R.O.C. phone: (412)–624–8423 fax: (412)–624–8465. Department of Computer Science University of Pittsburgh Pittsburgh PA 15260 USA

A multidatabase system (MDBS) is a system that integrates several autonomous database systems and provides users with a uniform access to all the databases. In this paper we developed a two-level active metadata dictionary approach for semantic query processing. To capture the global view of data schemas of participating databases which may be heterogeneous, a Hornclause data model is used. The lower-level metadata dictionaries (LLMDs) keep metadata for each corresponding local database in MDBS. The higher-level metadata dictionary (HLMD) integrates the metadata about all LLMDs. The database integration strategy includes two phases: schema translation and schema integration. It is a bottom-up approach integrating schema from the underlying database schemas. The evaluation strategy is a top-down approach. It starts with a query as a global goal to be achieved, unifies and optimizes the query to decompose the goal into subgoals that can be evaluated against extensional database, then translates these subgoals into corresponding queries against underlying DBMSs. To solve the control problem, we employ a G-net model for procedure control and inference control. An experimental implementation in Prolog is described.

关键词： multidatabase system metadata dictionary Horn clause database integration deductive database system semantic query optimization

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A real-time telerobot simulation and control environment through parallel processing

A real-time telerobot simulation and control environment thr...

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International Conference on Industrial Electronics, Control and Instrumentation

作者： G. Dodds T. Ogasawara School of Electrical Engineering and Computer Science Queen''s University Belfast Belfast UK Intelligent Machine Behaviour Section Japan

Telerobot systems require the commitment of robots and provision of mockup environments to permit training and facilitate the development of new techniques. Simulation in real time can test control strategies. Each of the possible configurations for an operation can be tested and the response can be used to produce optimum path and task plans. Parallel processing on transputers is considered to perform real-time dynamic simulation, for a seven degree-of-freedom robot, by a balanced division of the Newton-Euler formulation. Interfaces are provided to the actual hardware through both an advanced transputer/robot hardware interface and also a graphical interface to the user on a low-cost PC displaying real-time force and position information.< >

关键词： Parallel processing Hardware Computational modeling Manipulator dynamics Intelligent robots Parallel robots Costs Signal processing algorithms Testing computer science

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Enforcement of integrity constraints against transactions with transition axioms

Enforcement of integrity constraints against transactions wi...

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IEEE Annual International computer Software and Applications Conference (COMPSAC)

作者： S.H. Lee L.J. Henschen M.H. Kim Y.-J. Lee Database Section Electronics and Telecommunications Research Institute South Korea Department of Electrical Engineering and Computer Science Northwestern University IL USA Department of CS and Center for AI Research Korea Advanced Institute of Science and Technology South Korea

The authors address an enforcement technique of integrity constraints against transaction updates in a relational database system. Transition axioms have been used effectively in checking integrity constraints for single update statements. The authors extend the idea of transition axioms to a transaction which is a sequence of read and update statements. Integrity constraints in this scheme are simplified without database access before the actual operations are performed avoiding the need to undo an illegal transaction. Transaction partitioning, which can reduce the overhead of checking integrity constraints significantly, is proposed. Partitioning a transaction becomes crucial when a transaction is associated with multiple integrity constraints.< >

关键词： Transaction databases Relational databases Database systems computer science Artificial intelligence Control systems Law Legal factors

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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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Simulation of electromagnetic radiation and scattering using a finite difference-time domain technique

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computer Applications in engineering Education 1992年第1期1卷 45-45页

作者： Li, K. Tassoudji, M.A. Shin, R.T. Kong, J.A. Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge Massachusetts 02139 Kevin Li:received his BS and SM degrees (1990) in Electrical Engineering and EE (Electrical Engineer's) degree (1991) from the Massachusetts Institute of Technology where he is currently pursuing his PhD in Electrical Engineering. Since 1990 he has been the recipient of a United States Air Force Laboratory Graduate Fellowship. His main research interests include electromagnetic scattering radar cross section prediction and numerical techniques. Mr. Li is a member of Tau Beta Pi and a student member of IEEE. M. Ali Tassoudji:received his BS (1987) and MS (1989) degrees in Electrical Engineering from the University of Michigan Ann Arbor. Since 1989 he has been a research assistant at the Massachusetts Institute of Technology where he is currently working towards his PhD in Electrical Engineering. His research interests include electromagnetic scattering and propagation modeling of microwave circuits and numerical techniques. Mr. Tassoudji is a member of IEEE and Eta Kappa Nu. Robert T. Shin:received his SB (1977) SM (1980) and PhD (1984) in Electrical Engineering from the Massachusetts Institute of Technology. Since 1984 he has been a member of the Air Defense Techniques Group at MIT Lincoln Laboratory as a Research Staff member and as a Senior Staff member from 1989. His research interests are in the areas of electromagnetic wave scattering and propagation theoretical model development and data interpretation for microwave remote sensing. He is the coauthor ofTheory of Microwave Remote Sensing(Wiley 1985). Dr. Shin is a member of The Electromagnetics Academy IEEE American Geophysical Union Tau Beta Pi Eta Kappa Nu and Commission F of the International Union of Radio Science. Since 1987 he has served on the Editorial Board of theJournal of Electromagnetic Waves and Applications(JEWA). Jin Au Kong:is Professor of Electrical Enginee

The finite difference-time domain (FD-TD) technique is applied to the solution of Maxwell's equations. A computer program, which can be used to simulate and study numerous electromagnetic phenomena, is developed and implemented on an IBM 386 compatible personal computer. The FD-TD technique is a useful tool for students in electromagnetics. The technique is flexible and can be applied to many basic EM scattering and radiation problems. Because field solutions are found as a function of time, visualization of the propagation of the EM fields is possible. The FD-TD technique is implemented for a two-dimensional rectangular grid in conjunction with a second-order absorbing boundary condition. Both E- and H-field polarizations are analyzed. Finite objects consisting of dielectric, magnetic and conducting materials, and perfectly conducting infinite ground planes are modeled. Plane wave and line current sources are implemented. In addition to the capability of animating the propagation of the EM fields, radiation and scattering patterns can be generated.

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CAD CAM GOES TO SEA - THE SAAR-5 DESIGN AND CONSTRUCTION

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NAVAL ENGINEERS JOURNAL 1992年第3期104卷 148-155页

作者： LINDGREN, JR SOLITARIO, WA MOORE, AP STREIFF, MA John R. Lindgren Jr:. is vice president for engineering at Ingalls Shipbuilding Inc. a Division of Litton Industries in Pascagoula Miss. He joined Ingalls in 1958 and has held various positions in the Engineering Division and participated in the design of numerous merchant ships drill rigs submarines and surface combatants and auxiliary support ships. Mr. Lindgren is a 1958 graduate of the University of Southwest Louisiana. His degree is in mechanical engineering and he is also a licensed professional engineer. William A. Solitario:is the director of advanced technology at Ingalls Shipbuilding Inc. in Pascagoula Miss. He received his B.S. degree in chemical engineering from the City University of New York and has 28 years experience in marine engineering and design. His current responsibilities include the direction of Ingalls' IRAD programs and several Navy-funded R&D programs to improve ship's performance and reduce ship's operating costs. He is a member of the Society of Naval Architects and Marine Engineers and past chairman of the Gulf Section East Area. Arnold P. Moore:is the director design engineering at Ingalls Shipbuilding where he is responsible for all new construction design and engineering activities. Prior to promotion to his current position Mr. Moore served as chief naval architect at Ingalls. He has 24 years experience in ship design construction and repair. Mr. Moore holds the professional degree of ocean engineer as well as a master's degree in naval architecture and marine engineering from MIT. He also earned a bachelor's degree in naval science from the U.S. Naval Academy and is a registered professional engineer. Mr. Moore served as an engineering duty officer in the U.S. Navy and is currently a captain in the Naval Reserve. He is a past chairman of the Gulf Section of the Society of Naval Architects and Marine Engineers and a member of the American Society of Naval Engineers and Sigma Xi. Michel A. Streiff:is the manager of CAD/CAM applications at Ingalls Shipbuilding Inc. His

The SA'AR-5 Corvette Program is the first major warship construction to be entirely accomplished using a 3-dimensional, interference checked computer based design. This paper discusses the organization and approach used to create the design models which form the basis for interference checking as well as the source of extracted production data. The design or product model is the nucleus of the computer data base that defines the configuration of the entire ship. The data base includes geometry, weight, and material, as well as production control data. The ability of the computer to link such diverse information is the key to maintaining configuration control during the course of the design and construction. The ease with which formatted manufacturing data (both N.C. fabrication and installation) can be extracted enables the preparation of detailed packages containing the desired geometry as well as the associated material and sequencing data, thus assuring the producibility of the design. The SA'AR-5 design is CAD/CAM's state of the art in U.S. shipbuilding.

关键词： Warships

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ON THE POLYNOMIAL REPRESENTATION OF GENERALIZED LIOUVILLE OPERATORS

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JOURNAL OF SYMBOLIC COMPUTATION 1991年第3期12卷 373-379页

作者： SAILER, V MORALESLUNA, G Department of Electrical Engineering Section of Computer Science Centro de Investigación y de Estudios Avanzados del IPN Apdo. Postal 14-740 07000 México DF

The generalized Liouville operators are given as determinants of square matrices whose entries are higher order derivatives of real valued functions in two variables. The composition of these operators has very interesting properties in connection with polynomials over these operators. Their expansions grow so quickly that it is necessary to build efficient computer algorithms in order to manage them symbolically and to check inclusion properties. We prove that a general polynomial representation of the operator composition cannot exist, and we recognize other polynomial expressions, included in the composition, which group a great quantity of terms.

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Improving the performance of CELP-based speech coding at low bit rates

Improving the performance of CELP-based speech coding at low...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： T. Taniguchi F. Amano M. Johnson Radio Communication Processing Technology Section Fujitsu Laboratories Limited Kawasaki Japan Department of Electrical Engineering and Computer Science MIT Cambridge MA USA

The authors review the CELP (code excited linear prediction) coding algorithm, and the efforts recently made for improving the performance and reducing the complexity. The efforts for improving the coding performance have been aimed not only at making the quality better, but also at further reducing the bit rate without degrading the quality. A sparse-delta codebook is introduced as an example of a codebook with a computationally efficient structure. Multimode coding is then described for improving the perceptual quality of CELP at low bit rates.< >

关键词： Speech coding Bit rate Speech synthesis Speech processing Vector quantization Speech analysis Computational complexity Search methods Degradation Signal synthesis

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LPF and MPLω — A logical comparison of VDM SL and COLD-K 4th

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4th International Symposium of VDM on Formal Software Development Methods, VDM 1991

作者： Middelburg, C.A. Renardel De Lavalette, G.R. Dept. Of Computer Science PTT Research Dr. Neher Laboratories P.O. Box 421 Leidschendam2260 AK Netherlands Software Engineering Research Centre P.O. Box 424 Utrecht3500 AK Netherlands Section Applied Logic University of Utrecht P.O. Box 80126 Utrecht3508 TC Netherlands

ISBN: (纸本)9783540548348

This paper compares the finitary three-valued logic LPF and the infinitary two-valued logic MPLω, the logics underlying VDM SL and COLD-K. These logics reflect different approaches to reasoning about partial functions and bringing recursive function definitions into proofs. The purpose of the comparison is to acquire insight into the relationship between these approaches. A natural translation from LPF to MPLω is given. It is shown that what can be proved remains the same after translation, in case strictness axioms are added to LPF or removed from MPLω. The translation from LPF to MPLω is extended to recursive function definitions and this translation is next used to justify some ways of bringing the definitions of partial functions into proofs using LPF. © Springer-Verlag Berlin Heidelberg 1991.

关键词： Recursive functions

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A comparative study of three token ring protocols for real-time communications

A comparative study of three token ring protocols for real-t...

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International Conference on Distributed Computing Systems

作者： C.-C. Lim L. Yao W. Zhao Department of Electrical & Electronic Engineering University of Adelaide Adelaide SA Australia Net work Analysis Section Telecom Research Laboratories Clayton VIC Australia Department of Computer Science Texas A and M University College Station TX USA

When developing distributed scheduling algorithms such as communication protocols, issues in achieving optimal policy and minimizing overhead must be addressed. This problem is examined in the context of a specific distributed system-the token ring communication network. Three token ring protocols are considered which are representative of many existing ones in the sense that they incorporate message time constraints at different levels and implement the earliest deadline first transmission (scheduling) policy at different degrees with different overheads. Through a worst-case analysis, the performance of these three token ring protocols is compared. It is concluded that to evaluate a distributed scheduling algorithm such as a communication protocol, it is necessary to not only consider the scheduling policy employed but also to take into account the overhead incurred due to the implementation of the scheduling policy.< >

关键词： Token networks Protocols Time factors Scheduling algorithm Communication networks Telecommunications Laboratories computer science Context Performance analysis

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