SIMULATION: Transactions of The Society for Modeling and Simulation International

Belpedio, Ron

doi: 10.1177/003754979105600101pmid: N/A

Wildberger, A. Martin

doi: 10.1177/003754979105600102pmid: N/A

Fishwick, Paul

doi: 10.1177/003754979105600103pmid: N/A

This column focuses on a single topic within the field of computer simulation. All the material comes directly from the electronic news group (bulletin board) called Simulation Digest. The Digest can be obtained over INTERNET by accessing the news group 'comp.simulation' or by sending e-mail to: 'simulation [email protected]'

Unger, Brian

doi: 10.1177/003754979105600104pmid: N/A

Obaidat, M.S.; Radaideh, M.A.

doi: 10.1177/003754979105600105pmid: N/A

This paper presents a comparative simulation modeling of the performance of the uniprocessor, single-bus multiprocessor, and two-bus multipro cessor computer systems. The performance indexes of the single-bus and two-bus multiprocessor systems compared to the uniprocessor system, that are used in the modeling, are processor speedup factors SP1 and SP2 respectively. A third perfor mance index, Bus-speedup factor, SB, is derived to compare the performance of the two-bus and single- bus systems. The first two indexes provide measures of the processing speedup improvement of both multiprocessors with respect to the uniprocessor system, while the third index provides a measure of the performance improvement resulting from adding an extra bus to the single- bus multiprocessor system. Three data transfer protocols are considered in this work: First Come First Served (FCFS), Token Ring (TR), and the Priority (PR) Policy. Simulation experiments show that increasing the number of processors in the considered multiprocessor architectures does not necessarily improve the overall performance. Moreover, adding an extra bus to the single- bus architecture provides some speedup improvement that depends on the nature of the task program and the data transfer protocol. Simulation results show that FCFS and TR scheduling policies provide better performance than the PR policy. However, FCFS requires relatively less hardware and software complexity than the TR.

Pachter, M.; Briggs, M.M.

doi: 10.1177/003754979105600106pmid: N/A

We address the problem of how to properly handle the application of white Gaussian process noise to a digital simulation of a continuous-time linear dynamical system, given the standard device of a Gaussian random numbers generator.

Pearce, Bruce A.; Young, John F.

doi: 10.1177/003754979105600107pmid: N/A

A demonstration simulation program was developed on an IBM AT personal com puter to aid students in understanding the effects of altering rate constants on simple one and two compartment pharmacokinetic models. This menu driven system graphi cally presents specific sets of simulated curves illustrating how all components of a model interact. The student selects one of the five models and also determines which portion of the model is to be altered. The aim of the program is to teach the user to anticipate the outcome of the model alteration and interactions. The program was developed with the use of PC Storyboard, a demonstration software package, which provided the tools necessary for an elegant program presentation. This interactive presentation graphic program illustrates a viable means of conveying simulation models to a novice audience.

Malbasa, Veljko

doi: 10.1177/003754979105600108pmid: N/A

The basic goal of the project reported in. this paper was to design and implement an experimental multimicroprocessor system dedicated to the real-time parallel simulation of dynamic systems of various degrees of complexity. The implemented multimicroprocessor called RAMS is also used to study the parallelization concepts of dynamic system models. Potential applica tion of RAMS is in the process control area. The RAMS hardware architecture and software concepts, in particular the auto matic synthesis of RAMS application software, are given in some detail. The problems of both task creation and schedul ing in the non-deterministic RAMS environment are addressed. The experimen tal results show the power of RAMS through the parallel simulation of a case study dynamic system.

Nolan, Paul J.; Lane, Gearóid M.; Fegan, Joseph M.

doi: 10.1177/003754979105600109pmid: N/A

Present day approaches to discrete event simulation can be broadly classified as using either special purpose data-driven simula tion systems or general purpose simulation languages. Although the latter embrace a far wider range of applications and offer much greater flexibility in modeling for a particu lar application, their user base is restricted by the high level of expertise required.An Expert System interface to general purpose simulation languages, ISI (the Intelligent Simulation Interface), is pre sented here. Models are constructed and simulation runs are performed in an integrated environment comprising interactive menu-driven graphics, a knowledge base system and a general purpose simulation language. The features of ISI include hierarchical model construc tion, interactive experiment specification, automatic code generation, run-time animation and interactive graphical post- processing of results. An example case study is presented illustrating the main aspects of ISI. The ISI interface is shown to extend a general purpose language into an intelligent simulation environment.

doi: 10.1177/003754979105600110pmid: N/A