231 research outputs found
THE OBJECTIVES AND REQUIREMENTS OF MODEL MANAGEEMENT
Model management is a technology evolving by necessity, pushed by the attempts to deal with increasingly complex systems and the perceived inadequacies of past efforts. This rapid evolution of Model Management Systems
(MMS) has created different perspectives of the role of the MMS; one arising
the user's interaction with a model data bank and the other view from the
in the database and decision support systems research community stressing
modeling community emphasizing the model development functions. These two
perspectives are clarified and reconciled by relating each to the model life
cycle, which leads to a more comprehensive statement of MMS requirements
IMPLEMENTATION OF FORTRAN RANDOM NUMBER GENERATORS ON COMPUTERS WITH ONE'S COMPLEMENT ARITHMETIC
No abstract available
THE MIXED METHOD OF RANDOM NUMBER GENERATION: A TUTORIAL
Several motivations are recognized for user-defined random number generators
in preference to built-in generators. The mixed method of random number generation is discussed) and the conditions for achieving full period with a modulus of 2^b
are explained. Implementation of mixed random number generators is affected
both by the computer and language used. Guidelines are presented for realizing
acceptable mixed generators on several machines using the FORTRAN, PL/l and
SNOBOL4 languages
Systems and Methods for the Electrodeposition of a Nickel-cobalt Alloy
Systems and methods for electrodepositing a nickel-cobalt alloy using a rotating cylinder electrode assembly with a plating surface and an electrical contact. The assembly is placed within a plating bath and rotated while running a plating cycle. Nickel-cobalt alloy deposition is selectively controlled by controlling current density distribution and/or cobalt content in the plating bath while running the plating cycle to deposit an alloy of a desired yield strength onto the plating surface in a single plating cycle. In various embodiments, the rotating cylinder may be used as an insitu monitoring method to assist in obtaining the properties desired
A PROCESSOR UTILIZATION MODEL FOR A MULTIPROCESSOR COMPUTER SYSTEM
A processor utilization model for a simplified multiprocessor computer
system is developed. Jobs are assumed to arrive according to a general input
process, and each job is assigned randomly to an available processor. A
finite capacity input buffer is used if no processor is available. The mathematical model is based on the busy period analysis, and two utilization
measures are derived:
(1) processor utilization when the system is busy (the fraction of processor occupation time during a busy period), and
(2) global processor utilization (the fraction of processor occupation time during a busy cycle).
Additionally, the arbitrary time state probability distribution is obtained
and serves as the basis for the above measures in addition to others. Several
approximations enable the development of a computational model from the mathematical model. Experimentation with the computational model reveals the sensitivity
of the model to variability in the arrival process. Comparison of 2-processor
and 4-processor systems from the operator perspective indicates a qualified
preference for the behavior of the 2-processor system. This preference must
be carefully interpreted since processor costs, the increase in overhead with an
increase in processors, and behavioral variables reflecting the user perspective
are excluded
TO BE, OR NOT TO BE -- IS THAT THE QUESTION?
My purpose is to identify three fundamental questions regarding language
standardization, to share with you my answers to these questions, and to
explore the rationale emanating from these answers
STYLITISM, SYNERGISM AND SYNCRETISM: THE INTERFACE OF COMPUTER SCIENCE AND OPERATIONS RESEARCH
The interface of computer science and operations research is described from a stylitic perspective. This position enables an honest appraisal of the disciplinary synergism often claimed for the two. Operations research emphasizes the development of algorithms and the implications therein; while computer science gives primary emphasis to the representation of algorithms and the implications of execution on
a digital computer. The realization of a syncretic state can be claimed only for discrete event simulation and, to a lesser extent, for scheduling theory. To the extent that the "algorithm" can serve as common ground for both disciplines, a broader, more fundamental form
of syncretism might be achieved
A COMPARISON OF DISCRETE EVENT SIMULATION COURSES BASED ON A SMALL SAMPLE SURVEY
No abstract available
MODEL REPRESENTATION IN DISCRETE EVENT SIMULATION: THE CONICAL METHODOLOGY
Beginning with a brief review and classification of model development approaches, we characterize the simulation model life cycle
as comprised of seven phases:
the conceptual model, the communicative
model, the programmed model, the experimental model, model results, use of the model for integrated decision support, and the modification and
extension of of the model.
This characterization places severe
requirements on the task of model management (creation, acceptance, use,
revision or extension,
and reuse).
The Conical methodology has been developed in response
to the needs that
predominate the model
development
phases (from conceptual
model
to model
results).
Definitions used in the Conical Methodology are explained, and the approach is illustrated with a machine repairman example. An incomplete critigue of the result and the approach concludes the paper
Contemplations of A Simulated Navel
The Model Development Environment Project has the goal of defining the software utilities and the database support needed for creating, validating, and experimenting with complex simulation models. This project review, emphasizing the needs and explaining some of the guiding concepts and principles, serves to underscore key issues extending beyond discrete event simulation. An introspective summary presents an optimistic reaction to the fear that technically naive modelers might use the more sophisticated capabilities to produce catastrophic results
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