This article is a summary of an interpretive-systemic study of the University of Los Andes in Venezuela. Following the methodological guidelines of interpretive systemology, three interpretive contextual systems were ...
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作者：
SHOVAL, PInformation Systems Program
Department of Industrial Engineering and Management Ben-Gurion University P.O. Box 653 Beer-Sheva 84105 Israel
A methodology that combines and integrates the major stages of information systems development is presented. The methodology is based on hierarchical data-flow diagrams which are used to perform a functional analysis ...
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A methodology that combines and integrates the major stages of information systems development is presented. The methodology is based on hierarchical data-flow diagrams which are used to perform a functional analysis of the system. This enables the conducting of process design on the one hand, and information structure analysis and database schema design on the other. Specifically, we describe a method that connects the transactions of the system (the product of the process design stage) with the record-types (the product of database design stage). This connection closes the gap between the "procedural" and "structural" aspects of the system, and enables a smooth transition to the stage of system construction. It also facilitates the designing of sub-systems and their sub-schemas. Software tools that support all stages of the methodology are reviewed, emphasizing the tool DS2DS that connects the transactions with the record-types.
In the execution of a functional program, a large number of function instances are dynamically created, and these created function instances are executed as fine grain concurrent processes. In order to implement massi...
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An iterative decomposition method is presented for computing the values in an infinite-horizon discounted Markov renewal program (DMRP). The states are partitioned into M groups, with each iteration involving disaggre...
作者：
SHIRMOHAMMADI, AMAGETTE, WLSHOEMAKER, LL1 Adel Shirmohammadi is assistant professor of Agricultural Engineering at the University of Maryland
College Park (Agricultural Engineering Department 1108 Shriver Lab The University of Maryland College Park MD 20742-5711). He received his B.S. in Iran and his M.S. and Ph.D. from the University of Nebraska and North Carolina State University respectively. His current research interests include transport and shallow water table management modeling to quantify the hydrologic and water quality responses of agricultural watersheds.2 William L. Magette is assistant professor of Agricultural Engineering at The University of Maryland College Park (Agricultural Engineering Department 1126 Shriver lab The University of Maryland College Park MD 20742-5711). He received his B.S. M.E. and Ph.D. from Virginia Polytechnic Institute and State University. Currently his research and extension programs address water quality impacts of agricultural best management practices.3 Leslie L. Shoemaker is a former USDA National Needs Fellow in the Department of Agricultural Engineering where she is pursuing a Ph.D. degree (Agricultural Engineering Department University of Maryland College Park MD 20742-5711). The focus of her research program is on augmentation of the GLEAMS model to describe the hydrologic behavior of the vadose zone. She previously has been extensively involved in model applications for non-point source pollution control both in a graduate degree program at Cornell University and as an engineer with the Interstate Commission on the Potomac River Basin. She is currently employed as a water resources engineer with Green-home and O'Mara Greenbelt Maryland.
Non-point source pollution of ground water systems has become a national concern in recent years. Researchers and regulatory agencies are investigating the source and processes of the contamination. Agricultural best ...
Non-point source pollution of ground water systems has become a national concern in recent years. Researchers and regulatory agencies are investigating the source and processes of the contamination. Agricultural best management practices (BMPs) traditionally developed to reduce non-point source pollution of surface water resources are being investigated for their impact on ground water quality. This study used the CREAMS model to simulate the long-term effects of seven different BMPs on nitrate nitrogen (NO3-N) loadings to a shallow, unconfined ground water system. Two representative watersheds, 5.8 and 8.9 hectares (14.3 and 22 acres) in area, in the Coastal Plain physiographic region of Maryland were selected for study. Soils in these watersheds belong to the Matapeake silt loam series and have moderate infiltration capacity. Results from this study indicated that BMP's used in conjunction with winter cover (barley) reduced NO3-N leaching to the ground water system. It was also found that turfgrass reduced surface losses of water and nitrogen, but increased leaching losses of water and NO3-N significantly. All of the BMPs simulated in this study resulted in leachate NO3-N concentrations exceeding 10 ppm, the U.S. EPA health standard for public drinking water, indicating a need for alternate practices for reducing nitrate leaching.
作者：
KING, JFBARTON, DEJ. Fred King:is the manager of the Advanced Technology Department for Unisys in Reston
Virginia. He earned his Ph.D. in mathematics from the University of Houston in 1977. He has been principal investigator of research projects in knowledge engineering pattern recognition and heuristic problem-solving. Efforts include the development of a multi-temporal multispectral classifier for identifying graincrops using LANDSAT satellite imagery data for NASA. Also as a member of the research team for a NCI study with Baylor College of Medicine and NASA he helped develop techniques for detection of carcinoma using multispectral microphotometer scans of lung tissue. He established and became technical director of the AI Laboratory for Ford Aerospace where he developed expert scheduling modeling and knowledge acquisition systems for NASA. Since joining Unisys in 1985 he has led the development of object-oriented programming environments blackboard architectures data fusion techniques using neural networks and intelligent data base systems. Douglas E. Barton:is manager of Logistics Information Systems for Unisys in Reston
Virginia. He earned his B.A. degree in computer science from the College of William and Mary in 1978 and did postgraduate work in London as a Drapers Company scholar. Since joining Unisys in 1981 his work has concentrated on program management and software engineering of large scale data base management systems and design and implementation of knowledge-based systems in planning and logistics. As chairman of the Logistics Data Subcommittee of the National Security Industrial Association (NSIA) he led an industry initiative which examined concepts in knowledge-based systems in military logistics. His responsibilities also include evaluation development and tailoring of software engineering standards and procedures for data base and knowledge-based systems. He is currently program manager of the Navigation Information Management System which provides support to the Fleet Ballistic Missile Progr
A valuable technique during concept development is rapid prototyping of software for key design components. This approach is particularly useful when the optimum design approach is not readily apparent or several know...
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A valuable technique during concept development is rapid prototyping of software for key design components. This approach is particularly useful when the optimum design approach is not readily apparent or several known alternatives need to be rapidly evaluated. A problem inherent in rapid prototyping is the lack of a "target system" with which to interface. Some alternatives are to develop test driver libraries, integrate the prototype with an existing working simulator, or build one for the specific problem. This paper presents a unique approach to concept development using rapid prototyping for concept development and scenario-based simulation for concept verification. The rapid prototyping environment, derived from artificial intelligence technology, is based on a blackboard architecture. The rapid prototype simulation capability is provided through an object-oriented modeling environment. It is shown how both simulation and blackboard technologies are used collectively to rapidly gain insight into a tenacious problem. A specific example will be discussed where this approach was used to evolve the logic of a mission controller for an autonomous underwater vehicle.
The measurement or estimation of metabolic workload is an essential base for the evaluation of activities to make work assignment and the development of work-rest schedules and work methods. This paper describes a mic...
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The measurement or estimation of metabolic workload is an essential base for the evaluation of activities to make work assignment and the development of work-rest schedules and work methods. This paper describes a microcomputer program which performs systematic workload estimation based on the input descriptions of activity.
In software engineering, computer-aided software engineering tools are used to implement the methodologies of development in an automated or semiautomated environment. A number of tools are presented that were develo...
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In software engineering, computer-aided software engineering tools are used to implement the methodologies of development in an automated or semiautomated environment. A number of tools are presented that were developed to support ADISSA (Architectural Design of Information systems Based on Structure Analysis), a comprehensive methodology that treats analysis, design, and data modeling aspects as stages of a continuous process. This methodology covers in a unified way the stages of functional analysis, transactions (process) design, interface design, database schema design, input-output design, and structured prototyping. The personal computer-based ADISSA-supporting tools provide an automated environment that enables the analysts or designers, who work according to the methodology, to draw hierarchical dataflow diagrams and check their correctness, to design the transactions of the systems, the interface - a menu-tree - and the database schema, and to maintain an integrated data dictionary.
Discusses the design of a knowledge-based system (KBS), or a computer program which embodies knowledge about a particular domain or domains. Need for KBS design to focus on the types of reasoning required in the appli...
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Discusses the design of a knowledge-based system (KBS), or a computer program which embodies knowledge about a particular domain or domains. Need for KBS design to focus on the types of reasoning required in the application domain; Identification of reasoning tasks involved in expert problem solving knowledge needed to solve problems in the domain; Inclusion of an explicit design phase in the KBS development process.
The guide path layout for an automated guided vehicle system (AGVS) is a critical component in the overall design of a flexible manufacturing system (FMS) that utilizes AGVs for materials handling. Not only does it af...
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