bluuebunny/crossref_metadata_2025 huggingface dataset:
Computer-assisted modeling and simulation for time oriented systems
Authors: Retti Johannes
Published: January 2007

Most simulation systems are able to cope with large 'white box' problems, but their application proves to be difficult in case of 'grey box' and 'black box' problems in the social sciences. Even recently developed interactive tools for simulation and structural modeling cannot manage large scale models without difficulties. A computer-aided method is missing for the modeling and simulation of large-scale real-world problems. At the Department of Medical Cybernetics of the University of Vienna Medical School simulation languages and 'modeling tools' are applied in different non-technical fields. First our experience with four systems (CSMP, QSIM3, SPIN, SISSY) is described. A methodological concept is presented for computer-assisted modeling and simulation of time oriented systems. It provides among other features: user defined types of structural elements and relations by means of a meta-definition language; relational networks for the structural representation; defined interfaces between structural representation and processes; support of top-down and bottom-up approaches by incorporation of ordering relationships within the model entities; communication, useability and documentation for the novice and advanced modeler. The aim of the proposed new system is to encourage experimental modeling and simulation of comlex real world problems and to gain an appropriate level of detail. The concepts for the realization are presented.
Modeling the lines at the gas stations
Authors: Schneider Alan M. , Papadopoulos Gregory
Published: January 2007

A simulation model of the gasoline delivery system demonstrates the panic and formation of long lines at service stations. The dynamics of this process are similar to those observed in Southern California in the Spring of 1979.
To be, or not to be
Authors: Nance Richard E.
Published: January 2007

To elaborate on my paraphrase of the famous line of the Danish prince, I suggest that we pause to consider (perhaps reconsider) the proposed exercise in simulation language standardization. My intent is not to be obstructive, and I beg the indulgence of those of you who are already muttering about "the same old tired arguments against standardization." 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. If the questions are irrelevant, inappropriate, or inconsequential, please accept my apologies. If the questions are relevant, appropriate, and of consequence and, more important, the answers seem meaningful, then perhaps we can perceive clearer directions toward the improvement of simulation methodology.
Systems hierarchy as a basis for simulation model description
Authors: Zeigler Bernard P.
Published: January 2007

This paper elaborates an integrated hierarchy of model description formalisms previously proposed. We discuss the advantages of the hierarchical approach vis a vis a standardized universal model description language. Among the principal advantages are the opportunities provided for concise model specification while at the same time enabling equivalence testing of models expressed in diverse formalisms.
Standardized expression of rate-state relations
Authors: Benyon P. R.
Published: January 2007

It is unlikely that the Workshop will get far towards drawing up detailed standards in only two days, so priorities need to be considered. I believe first priority should be given to the parts of the language(s) concerned with defining the model and second priority to the parts concerned with running it, although these parts too are important.
Choosing a language for an MBA system modeling and simulation course
Authors: Archer Norman P.
Published: January 2007

Simulation languages develop and evolve over time, and the courses in which modeling and simulation are taught must also evolve to keep pace. In the McMaster University MBA program, a study was undertaken in order to select a new simulation language for a system modeling and simulation course in which GPSS had previously been used, in order to demonstrate a broader possible selection of possible application areas for simulation. The language which was selected was SLAM II, and this selection was confirmed by monitoring the reactions and perceptions of the students to both the old and new languages, which were taught concurrently in two separate sections.
A high speed list processor for discrete event multiprocessor
Authors: Barel Meir
Published: January 2007

List processing plays a central role in simulation programs. It is apparent that a distributed list processing is essential for a distributed simulation. The list processor reported here is a special microprogrammed processor, according to the co-processor concept, whose architecture 1) is optimized for the execution of list and arithmetic operations, and 2) support distributed list processing on several list processors. In order to accommodate a wide range of list applications a comprehensive basic instruction set has been implemented which allows the execution of many desired list operations, e.g. complex searching and sorting algorithms. For a specific application (e.g. event list manipulation) a high level instruction set can be built by using these basic instructions. For attribute manipulation an arithmetic instruction set (floating point) is also included.
A network interface unit simulation using micro PASSIM
Authors: Vayda Tom P.
Published: January 2007

This paper describes how micro PASSIM, a GPSS based simulation system, was transported from the Apple II to the HP 9836. The problems associated with moving a large program form one UCSD Pascal system to another are discussed. Micro PASSIM was transported to the HP system so that an Ethernet to HPIB interface board could be modeled. The model is described and the results obtained from the simulation are discussed. A discussion of the advantages and disadvantages of using micro PASSIM rather than a standard language, such as GPSS, is also included.
A simplified stopping rule for simulations
Authors: Solomon Susan L.
Published: January 2007

When running a computer simulation it is often a matter of debate whether the run length is sufficient to yield an 'acrruate' estimate of population parameters. Since the run could continue indefinitely, the population is potentially infinite and no limited sample will provide perfect point estimates. However, confidence intervals can be computed in the customary fashion, with options to vary sample size, confidence level and degree of precision. For example, suppose it is desired to estimate the true utilization rate, ϕ, for some facility. The simulation run yields the sample utilization rate, [EQUATION], for the total run length. If the assumptions of the Central Limit Theorem can be applied,[EQUATION]where 100 (l - α) is the level of confidence selected and the sample size is assumed to exceed 30 to justify the general use of
z
statistics.
Features of a general continuous systems network simulator
Authors: Whipple Walter L.
Published: January 2007

In the last few years, a large number of simulation programs has been developed for the solution of specialized problems. These programs differ in a number of respects, but the most important reason for their development seems to be an unwillingness to use a tool which does not use input-output forms which are familiar to the user. Of course, the algorithms and problem formulations also differ, but it is not obvious to the author that there is any reason why different algorithms would be necessary for electrical and electronic circuits analysis, for example. Many simulation studies need a network analysis capability whether the investigation involves electronics, structures, thermodynamics, or industrial dynamics. Yet no general purpose simulation language seems to provide the capability with sufficient flexibility to replace the many special purpose programs now being used. It is the thesis of this paper that such a general purpose simulator is feasible and desirable.
The clinical microscopy laboratory system
Authors: Dumas M. Barry , Valinsky David
Published: January 2007

This paper deals with the simulation of hospital laboratories --- in particular the clinical microscopy laboratory system. This system is representative of those that deal with the patient indirectly. While analyses are made of samples drawn from patients, the patients' presence is not required for test performance.The nature of the simulator which has been developed is discussed. Special reference is made to five particular aspects whose treatment defines the basic characteristics of any such simulator: event definitions and timing; demand characterization; decision variables; output data management; measures of effectiveness. Emphasis is on the approaches taken rather than the programming details used.
An approach to the collection, representation and simulation of program execution behavior
Authors: Feingold Robert S.
Published: January 2007

Most computer system modeling efforts must address two important implementation questions: first, how will hardware resource characteristics be modeled and second, how will program resource demand characteristics be represented. The first question, although extremely interesting, is deferred for another time. This paper describes a technique developed to partially answer the second question.
6th annual simulation symposium
Authors: Baldonado Orlino C.
Published: January 2007

This paper uses the computer simulation studies of bulk mail flow through the New York Bulk Mail Center. The model was used primarily to assess the sack and parcel processing capacity of the Bulk Mail Center and to predict how the system will perform under various mail volumes and equipment malfunction conditions. The model provides a tool to be used for controlling resources.
Uniform random numbers in APL
Authors: Franta William R.
Published: January 2007

In the article by R. Wheeler, the author laments the integer nature of the APL operator ? when faced with the need to construct a generator which produces random numbers uniformly distributed on (0, 1). The difficulty arises in that the definition specifies that
? X
returns a random integer from 1 to X inclusive. It is indeed unfortunate, since in many ways APL is ideally suited to Monte Carlo experiments. Recently when designing and implementing an APL processor for the CDC 6600, the deficiency was clearly recognized. Under such conditions three possibilities exist in choosing a course of action, namely: (1) the deficiency can be ignored, (2) the operator definition can be altered, and (3) the operator definition can be extended. The design effort dictated that the processor be consistent (in every conceivable way) with the specifications given in [2] thus disallowing (2). This is important so that APL remains APL rather than a series of dialects all labeled APL. The only possible route for emmendation of the deficiency that remains, therefore, is (3).
The Astro-spiral jump
Authors: McHenry Raymon R.
Published: January 2007

An unusual application of a digital simulation of automobile dynamics to the design of a thrill show stunt is described. The rationale for development of the simulation, which is intended primarily for highway safety applications, is discussed and the general analytical approach is described. Computer graphics displays of simulation outputs, consisting of detailed perspective drawings of the vehicle and terrain features or obstacles at selected intervals of time during a simulated maneuver, are presented as figures in the text. For the presentation of the paper, computer graphics displays of simulation outputs will be animated through the use of motion picture film. Also, motion picture coverage of both developmental tests and public performances of the Astro Spiral Jump will be shown.
MIT Simpl
Authors: Jones Malcolm M.
Published: January 2007

Simpl is a simulation system (i.e., a specialized programming language and an associated run-time support system) specifically designed to provide a high degree of interaction between an individual researcher and a complex simulation model, in all the stages of the simulation process, by taking advantage of the sophisticated interaction possible in a modern, on-line, man-computer environment.
University simulation models
Authors: Wartgow Jerome F.
Published: January 2007

Recent years have seen much activity in simulation modeling for research and planning, and several organizations have developed simulation models designed especially for use by administrators of higher education. Although the power and sophistication of this tool have been proven in areas of business and government, many questions remain to be answered about the effectiveness of these models as an aid to administrators of higher education.
Report on selected readings on digital computer simulation
Authors: Bazjanac Vladimir
Published: January 2007

The title of this text immediately reveals who it is written for: architects who are interested in computer applications. The author is assuming that the general reader in the field of architecture has absolutely no background in the field of computing and the text is therefore written on a very low level of sophistication, at which the simplicity is exaggerated. Though the text as a whole is probably helpful for an uninformed reader to learn about applications of computers to architecture, a more sophisticated reader will find reading of all but a few sections a waste of time. For a person with specific interests in the field of architecture and computer applications, those few more successful parts are probably quite worth reading, if for nothing else, then just for exposure to what is actually being done in that area. Besides that, an uninformed reader may find it interesting to get exposure to British hardware and ALGOL-based programming practice, as well as British terminology.
Algorithmic generality in memory management design
Authors: Kumar Dinesh
Published: January 2007

As computer systems grew in complexity, the area of memory management has become increasingly important. In future operating systems what is needed is a generalized, flexible, modular, and open ended-design of the functional modules (e.g. memory management modules). To achieve these properties, sufficient ingenuity and effort are required during both design and implementation. This paper outlines an approach which should lead to a design having these properties. A memory management system was designed using this generalized approach. The system was subsequently modeled and implemented in SIMSCRIPT I.5 as a test case. The model and the successful results prove the feasibility of the approach and can be used to evaluate different memory management schemes. The functional modules within the model are general so that their mode of operation can be set from outside (this may be called parametric generality). However, the actual algorithm employed for memory management can be tailored at the site generation (or system generation) time using a convenient specification language. This design strategy is best characterized by the term "Algorithmic Generality."
The academic department head game
Authors: Chapman Stephen C. , Osborne John E.
Published: January 2007

"The Academic Department Head Game" is a computerized management exercise (computer programs are written in American National Standard Fortran IV) designed to emphasize the more important decisions that must be made by an academic department head. The player assumes the position of head (or chairman) of the Department of Statistics at the State University of Id, a typical land-grant institution, with the objective of maximizing his departmental reputation.
On the control of a clinker cooler through state variable techniques and simulation
Authors: Cronhjort B. T.
Published: January 2007

This paper relates to an exploratory computer control project for the digital control of a cement plant. The control of the clinker cooler was part of the project. State variable techniques were applied for the synthesis of the control system. Here, the emphasis will be on off-line simulation. A control law will be generated for the control of the over grate differential pressure. It is claimed that simulation techniques are essential tools for the successful design and implementation of digital control in industry.
A problem in production management
Authors: Schriber Thomas J.
Published: January 2007

In a certain factory, a tentative operating objective is to keep 50 machines of a particular kind in production 8 hours a day, 5 days a week. Management owns 50 machines of the kind in question, and employs 50 machine operators to run the machines. An operator can only run one machine at a time. And, because of production restrictions, it is infeasible to have any of these machine operators work overtime. Under ideal conditions, the tentative operating objective could be met with the 50 machines and 50 operators. Unfortunately, each of the machines is subject to random failure. A machine's production lifetime is 160±25 hours (uniformly distributed). Whenever a machine fails, it is sent to an in-house repair shop, which is manned by two repairmen.
Simulation of networks using multidimensional Fast Fourier Transforms
Authors: Barto Andrew G.
Published: January 2007

A fast method is presented for simulating a class of systems that includes certain regular neural networks based on neurons that perform a weighted spatial summation as a part of their operation. The method employs high-speed convolution via the Fast Fourier Transform. Some important aspects are emphasized: first, even though the FFT is essential, the neurons do not need to be completely linear (they can have time varying thresholds for example); second, simulations of networks with very dense interconnections are encouraged (they take no more time then sparse ones using this method); and finally, the method is suggestive of similar but more general computational schemes.
A simulation approach to the design of dynamic feedback scheduling algorithms for time-shared computer systems
Authors: Bauer Madeline J.
Published: January 2007

The goal of a scheduling algorithm for a time-shared computer system is to provide acceptable request response time and resource utilization through effective resource allocation. In order to do this, it is necessary for the algorithm to be capable of adjusting itself to handle the various situations, precipitated by the set of active user requests and the computing system's status, which may occur. An effort is now underway to design the structural framework of a scheduling algorithm which will dynamically formulate its resource allocation policies and adjust its policy formulation depending on the success or failure of those policies. Once designed, the framework will then be used to construct the scheduling algorithm for a given time-shared computer system.The approach chosen for determining the practicability of the algorithm design is the inclusion of the algorithm in the simulation of a swapping time-shared computer system model. The simulation contains four basic activities: processor, input/output, swapper, each of which contains a resource allocation policy for determining a priority ordering among those requests which have asked for the respective resource, and the user activity. User activities follow one of a number of simulated scripts which may be composed of several types of requests. Each request is given behavioral traits dependent on its type.While the complete algorithm is not yet implemented within the simulation, preliminary results suggest that some improvement in response time may be possible.
GASP IV can broaden your modeling perspective
Authors: Pritsker A. Alan B.
Published: January 2007

Simulation modeling can be constrained by the simulation language with which you are familiar. GASP IV eliminates many constraints by combining discrete and continuous concepts into one language.
A ship off-loading problem
Authors: Teorey Toby J.
Published: January 2007

Sea Port operations consist of the off-loading of ships and transfer of cargo away from the pier so that other ships may be efficiently processed. The major system components of such an operation are the ship, the pier area, intransit storage approximately 2 miles from the pier area, and an inland storage depot at a distance of 56 miles from the sea port. Transportation for the cargo is provided by 2 hooks on board ship, 4 forklifts (12,000 lb.) at the pier, 10 5-ton trucks and 2 additional forklifts available at both the intransit storage area and the inland depot. The cargo on board ship is of three categories: containerized in 20' x 8' x 8' boxes, palletized on 7' x 8' pallets, and bulk cargo.
A multiprocessor memory interface simulator
Authors: Taylor D. S. , Williams T. , Weatherbee J. E.
Published: January 2007

A simulater is described which models the interference produced at the interface between a common central memory (CM) and a number of microprogrammed central processing units (CPU's) operating under the control of a microprogram read-only memory (MROM).Results of the interference study may be used to determine the optimum combination of the CM/ CPU bus width and the CPU Microprogram MROM cycle time.
An introduction to the application of simulation in Computer Performance Evaluation
Authors: Tryggestad Thomas N.
Published: January 2007

The purpose of this paper is to outline, very briefly, the application of simulation techniques to Computer Performance Evaluation (CPE) problems. It covers situations where the use of simulation is appropriate and some cases when it is not. It also includes a discussion of the types of questions simulation can help to answer and how to go about finding the answer.It must be kept in mind always that simulation is a part of the larger world of CPE, in general. The other elements are hardware monitoring, software monitoring, statistical analysis, benchmarking and other analytical tools. Each of these tools has its strengths and weaknesses and must, therefore, be properly applied. Another factor to keep in mind is that the use of these tools is not mutually exclusive, i.e., they should be used to complement each other whenever appropriate rather than totally by themselves. This discussion deals with simulation as a CPE tool, not the CPE tool. More and more, the various tools are being used together to find solutions to problems. Some of these instances will be brought out in the discussions to follow.
Simulators and assemblers for minicomputers
Authors: Fisher Donald D.
Published: January 2007

Program debugging for minicomputers with paper tape input can be a frustrating and time consuming process. One way to simplify this process is to develop a simulator for the minicomputer which operates on a large host computer. The assumption is made that turn around time on the host computer is reasonable and that debug diagnostics are included. The first step of the simulator design is to develop a hardware reference language description of the instruction set. This step is useful even if a simulator is not developed because it requires one to obtain a complete understanding of the instruction set, the registers, and the interactions of all of the control signals. Such understanding is a prerequisite to the development of successful programs for the mini, especially at the assembler level. This paper describes the implementation of simulator-assembler packages for minicomputers.
An introduction to CAPS
Authors: Hutchinson G. K.
Published: January 2007

This paper describes CAPS, a simulation system which enables an analyst without programming experience to quickly produce (in hours) guaranteed executable programs through the use of an interactive dialog. The result is a substantial reduction in both time and effort from the point of problem definition to the availability of model output for decision making. CAPS was developed by Dr. A. T. Clementson of the University of Birmingham and this paper draws heavily upon his work. (See Ref. 1) The user dialog with CAPS is described and examples of the ease of use are given, including an actual model.
Simulation of error detection in computer programs
Authors: Schneidewind Norman F. , Green Thomas F.
Published: January 2007

The relationship between computer program complexity and error detection capability is investigated by representing a program as a directed graph and simulating the detection and correction of errors. Variables of interest are test coverage, number of inputs, residual errors, execution time, correction time and node-arc-loop relationships. One application is in software design where the information provided by the model would be used to select program structures which are easy to test. A second application is in software testing where test strategies and allocation of test effort would be based on error detection and complexity considerations.
The relationship between the multiplicative and mixed generators modulo 2
b
Authors: Overstreet C. L.
Published: January 2007

In 1951, D. H. Lehmer [4] first proposed the linear congruential technique, X
n+1
≡ aX
n
+ c (Mod M) as a source of random numbers. This technique has since become known as the multiplicative random number generator for c = 0 and as the mixed random number generator for c ≠ 0.
Putting statistics into a SIMULA program
Authors: Palme Jacob
Published: January 2007

Statements for outputting a trace of what happens during a simulation, and for collecting statistics to be output after the end of the simulation, should not clutter up the main logic of the simulation program.This paper shows with a simple example how a SIMULA program can be structured such that the tracing and statistics and the main logic of the simulation program are partioned into different segments of the program.The paper will, at the same time, show the general facilities which SIMULA has for this kind of program structuring.
Corporate simulation models
Authors: Naylor Thomas H. , Jeffress Charles
Published: January 2007

Within a period of less than five years, computer-simulation techniques have penetrated corporations in the United States, Canada, and Europe at the highest possible level. This paper summarizes the results of a survey of 346 corporations, most of which are either using, developing, or planning to develop some form of corporate simulation model. Among the questions addressed by the survey for which empirical answers have been sought are: Who is actually using corporate simulation models? Why are they being used? What resources are required to develop them? What techniques are employed? How much do they cost? What are the benefits to be derived from their use?The paper concludes with a series of specific recommendations for improving the effectiveness of corporate simulation models. First, corporate models should be made more user-oriented. Second, more attention needs to be given to the production activities of firms. Third, the possibility of integrating optimization models into corporate models needs to be explored further. Fourth, financial, marketing, and production models should be linked together. Fifth, the use of models to simulate the global environment of corporations should be considered. Sixth, greater emphasis should be placed on the "politics" of corporate model building.
Event
Authors: Katz Leon
Published: January 2007

A standard set of event-scheduling simulation program modules is presented. The basis for these program modules is empirical and subjective. In the author's experience, the arrangement of a program into these modules has proven beneficial.
Modeling the ice-age climate
Authors: Gates W. Lawrence
Published: January 2007

The last great (Wisconsin) ice age has long held the interest of climatologists, geologists, and geographers as the best documented of the several ice ages of the last million years. Although local glaciation maximums varied by several thousand years, the time 18,000 B.P. (years before present) is globally representative of this event. The changes of flora and fauna that accompanied this ice age are recorded in an extensive paleoclimatic literature, and are supplemented by widespread evidence of changes in the physical character of the earth's surface, such as changes in sea level, sea-ice extent, and local orography. From these and other evidence, estimates of the local nature of the ice-age climate itself have been derived at selected sites in terms of such variables as the local wind, temperature, or rainfall. Although they are insufficient to portray the overall global climatic regime, these estimates indicate that the ice-age climate was substantially different from today's in many regions of the world.
A computer simulation model for medical school planning
Authors: Milch Robert Austin , Bhatia Narain D.
Published: January 2007

Management and management accounting concepts and practices---which at an earlier time were of interest to only a few medical school administrators and to still fewer medical school faculty members---have suddenly taken on urgent proportions for many, perhaps even most, American medical schools. Faced with an unhappy combination of increasing demands for ever-broadening public service and public accountability on the one hand, and of an inflation economy with steadily escalating scarcities of manpower, materials, time and, especially, financial resources on the other, medical school faculties and administrators all too frequently now find themselves in the distinctly unenviable position of having to make complex policy and operating decisions of a nature and scope never before required.
Some mathematical properties of simulation models
Authors: Iazeolla Giuseppe
Published: January 2007

A mathematical style of description of simulation models is introduced by using the formalism of system theory. Discrete event simulation models which use pseudorandom number generators are regarded as abstract objects described by a family of input-output time-functions and are proved to hold the property of aggregates.
Modular modeling for planning hospital emergency facilities
Authors: Johnson G. Miles , Winter James A.
Published: January 2007

The emergency facility is the entry point for different classifications of patients, various types of treatments are carried out, and some of the patients are hospitalized, although most are treated and sent home.Processing procedures are modeled under specific sets of assumptions to assess relative advantages of alternative design configurations. Parameters such as mean service times and resulting queues are examined and recommendations made. To assist hospital planners without specialized knowledge of simulation techniques, a tutorial account presents how to utilize recently developed modular modeling techniques in terms of model development. A step-by-step discussion details how modular modeling can pinpoint design-induced bottlenecks in planned facilities prior to implementation. Specific attributes modeled are:• Patient arrivals, by classification.• Patient waiting line, due to registration procedures.• Registration procedures (delays).• Patient waiting line, prior to treatment.• Treatment service times.• Total patient transit times.
Review of "Theory of Modeling and Simulation, by Bernard P. Zeigler", Wiley-Interscience Publication, John Wiley & Sons, 1976
Authors: Highland Harold Joseph
Published: January 2007

Simulation to many outside our field is the 'tool of last resort,' when all else fails ...... To many in the simulation field, we are conent in our modeling and simulation techniques primarily because, through experience, we have found that they work, at least most of the time. On the other hand, many computer scientist has looked askance at simulation since it is not a true hard science discipline; consider, for example, the many papers in which simulation is still considered an art.
An automatic data generating system for data base simulation and testing
Authors: Lyons Norman R.
Published: January 2007

It would seem in this age where much is heard of the "information explosion," the last thing the world needs is an automatic system for the generation of data. And yet, there are many instances in management systems design where such a system is very useful.
Combination of an optimization model for hardware selection with data determination methods
Authors: Scheer A.-W.
Published: January 2007

The selection of an EDP configuration often fixes a firm to a single manufacturer for a long time and the capabilities of the chosen computer will continually influence the firm's organization. Only few approaches exist to give assistance to the investors by developing useful decision models based on the investment theory /11, 12/. The hardware selection methods /4, 13/ used up to now, like benchmark tests, don't meet these demands. In this paper an investment model based on mathematical programming is developed which considers the aspects of investment for hardware selection.
Nonparametric selection procedures applied to state traffic fatality rates
Authors: McDonald Gary C.
Published: January 2007

This article reviews the practical aspects of several nonparametric subset selection rules useful in block design problems, and discusses advantages and disadvantages of these methods. The populations are assumed stochastically ordered by the parameter of interest. Rules based on ranked observations are given for selecting a subset of populations which contains, with a specified confidence level, the population characterized by the smallest (or largest) parameter value. These procedures are applied to state traffic fatality rates recorded yearly (1960-76). New England states and Middle Atlantic states comprise most of the subset asserted, with a 90% confidence level, to contain the state with the smallest fatality rate; whereas, Southern states, Southwestern states and Rocky Mountain states generally comprise the subset for the state with the largest fatality rate. Note that while this example is not based on simulation data, such data would be analyzed in exactly the same fashion.
The role of statistical methodology in simulation
Authors: Kleijnen Jack P. C.
Published: January 2007

In practice, a most popular method to study complex systems is simulation. However, a major practical drawback of simulation is its ad hoc character. After spending much mental effort and computer time to develop, program, and run a computer simulation, strictly speaking, the results are valid only for the specific parameter values and structural relationships of the executed simulation program (or programs). Changing a parameter or relationship means that the simulation program has to be run again. Yet, such changes are necessary to answer "what if" questions, to find optimal system configurations and, not to be forgotten, to establish the sensitivity of the conclusions to specific model assumptions.
Simulation and optimization techniques in scheduling farm operations
Authors: van Elderen E.
Published: January 2007

Planning a farm concerns the selection of activities, crops and cattle (what to grow), the selection of machinery, tractors, equipment and installations and the scheduling of operations (how to produce). A sequence of operations is needed to achieve the final products or materials; for example, mown alfalfa needs field drying, windrowing, baling and storing. From one material, alfalfa on a field, two others result, bales in the store and a field with aftermath for a next cut or a field needing soil cultivation for growing another crop next year. The operations are performed by gangs consisting of men, tractors and equipment. Only some gangs can operate simultaneously due to the limited number of men, tractors and equipment. There exists a finite set of combinations consisting of the gangs operating simultaneously. The weather influences directly or indirectly the possibility to perform operations by the moisture content of the soil (trafficability) or of the processed material itself, for example, alfalfa hay for baling may not be too wet.
Simulation optimization using response surfaces based on spline approximations
Authors: Daughety Andrew F. , Turnquist Mark A.
Published: January 2007

This paper presents an approach designed to increase the efficiency and utility of search for optima of simulation models. Specifically, spline functions (odd-order polynomials fitted between simulation run outputs that match curvature at the end points) are used to approximate the simulation along suitably chosen directions of search. The splines are used to generate "pseudo-experiments" which enrich the data base formed from actual simulation runs. An overall (grand) function is then fit to this data base, yielding new direction(s) of search for the next iteration. Several characteristics of this technique are examined, including its sensitivity to experimental budget, number of iterations allowed, and size of feasible region.This approach results in not only an estimate of the optimal response from the simulation, but also a response surface estimated over a larger domain useful both for sensitivity analysis and in some cases as an approximate representation of the simulation for use in other modeling efforts. The paper describes an application of the technique to a model of a railroad classification yard. The objective is to find the numbers and sizes of inbound and outbound trains, and the dispatching policy within the yard, which minimize total car delay.
Financial modeling...simulating your way to planned objectives
Authors: Centofanti Joseph J. , Evans David C.
Published: January 2007

The objective of this report is to relate our experience in developing, implementing and maintaining a financial model in a capital goods manufacturing enterprise. Particular attention will be given to the practical aspects of financial modeling, and to the impact upon all levels of management within the organization. Actual examples will be presented throughout to emphasize the practicality and simplicity of the model.The model was developed to meet the specific needs of a division. Since its inception almost two years ago, the model's proven reliability has led to its acceptance throughout The Warner & Swasey Company as the corporate and divisional financial planning standard. Thus the model has been used successfully for several industries, ranging from machine tools to construction equipment, textile equipment and electronic accessories. We hope to share the perspective gained through this development and acceptance process.
Management oriented documentation of simulation
Authors: Silbey Val
Published: January 2007

Simulation documentation for management is the written report that describes what a simulation does. It acts as a communications medium between the simulation modeller and the recipient of the report.The major problem with most management reports is the level of difficulty that reader faces. Wading through paragraph after paragraph of turgid prose makes a management report difficult to read.This problem can be overcome by careful attention to the rules of good technical writing. It is best handled by a documentation specialist rather than the simulation modeller, because the skills required for clear documentation are different from the skills required to design and program a simulation.Management oriented documentation is oriented toward the presentation of conclusions and recommendations. It will add about 10% to the cost of a simulation project. But without good documentation the project may be wasted.
Dynamic simulation of a national resource sharing computer network
Authors: Segal Ronald , O'Neal Beverly
Published: January 2007

A national computer network for research and educational institutions has frequently been proposed as a means for meeting selected computing needs in an effective manner. Although many technical problems remain, it is generally believed that the most difficult issues facing such a network revolve around economic, political, and organizational considerations. In order to investigate these issues, a model of a computer network was developed to test a variety of networking alternatives, and to evaluate the ways in which a network would impact its member institutions.This paper describes the use of the simulation model in a three day gaming exercise by sixteen institutional teams who made decisions about their likely participation in a network that "progressed" through several years of simulated time. Participants were able to interact dynamically with the decisions and actions of other participants, to deal with a variety of network issues, and to explore the relative advantages and disadvantages of various modes and levels of network participation.This project represented an unusual and different application of a simulation game in that it concentrated on the policy and behavioral aspects (i.e., people concerns) of what is usually considered to be a technical design problem. The players were real decision makers, playing themselves as they relate to their own institutions, rather than students. Consequently, it was possible to focus on learning about the implications of national networking, rather than merely demonstrate or teach known principles.
Examining alternative End-Stage Renal Disease (ESRD) therapies through simulation
Authors: Roberts Stephen D. , Gross Thomas L. , Maxwell Douglas R.
Published: January 2007

To examine the costs and effects of alternative treatments for End-Stage Renal Disease (ESRD), we constructed a simulation model which estimates patient survival and lifetime cost for those with ESRD. The model, written in the INS simulation language, considers home and center hemodialysis as well as live related and cadaver donor transplantation. After the model was validated, the cost per life year gained for each therapy was computed. Center hemodialysis was found to have the poorest cost-effectiveness and shifts from center hemodialysis could save society up to $284 million annually. We conclude that the model may be very helpful in designing cost-effective care for End-Stage Renal Disease.
Effective management of simulation and modeling projects
Authors: Clema Joe K. , Rowe Dale , Roth Paul
Published: January 2007

Effective management and control of modeling and simulation projects can provide significant savings in the development of large-scale, complex, multidisciplinary systems. With the evolution of the techniques of modeling, simulation and software engineering from "art to science", must come discipline. Discipline is the responsibility of the manager, and for him to effectively control the development of today's projects he must have a detailed understanding of the simulation software phased, cascading life-cycle. With this knowledge, the manager can develop an effective simulation methodology to attack the major cost problems of analysis, design, visibility, testing (verification/validation), standards, concurrent documentation, configuration management, reliability and quality control. To understand the software life-cycle, one must first understand that it is unlike any other product and thus an effective modeling and simulation methodology will require some techniques and mechanisms which differ from the classical management patterns.
Problems, prospects, and an alternative approach in simulation modeling
Authors: Fetter Robert B.
Published: January 2007

Early work (1950's) in simulation and first attempts at modeling of health care facilities utilization are described. Lessons learned from this work are given together with perceived limitations of available technology, the development of the Conversational Modelling Language and its implications for OR in general and simulation in particular are described.
The use of computer simulation to develop hospital systems
Authors: Hancock Walton M. , Walter Paul F.
Published: January 2007

The use of computer simulation in the development of hospital systems, which has a major effect on the cost and quality of operation, is presented. Discussion of results achieved in specific areas include: inpatient admissions scheduling and control systems, surgical scheduling systems, maximum average occupancy prediction models, and patient classification systems for predicting the size of nursing staffs. The paper concludes with a discussion of the general problems encountered with computer simulation.
"RAD SIM"
Authors: Harvey Robert O.
Published: January 2007

"RAD SIM" is a GPSS model developed to simulate Radiology Room utilization. The model provides reports that facilitate the interaction of the management consultant and the appropriate client. The simulation methodology provides the users with the ability to respond to "what if" questions, and to test changes to the Radiology operating system without implementing the modifications.The model requires data to be collected on patient arrivals, procedure scheduling criteria, and radiology room capabilities. Output from the model reports individual room utilization and waiting lines. Other statistical information is provided in the simulation report."RAD SIM" has been used in a number of consulting engagements with major success. Radiologist and consultant interface has proved to be quite beneficial for the long-term success of systems changes.
Simulation as a decision aide
Authors: Marsh John J.
Published: January 2007

The environment and growth of management problems found in a modern health care institution are briefly discussed. The techniques of computer simulation are suggested as a realistic approach to the solution of some of the complex operations problems, especially from a planning perspective. Two examples of the application of simulation analysis are cited with particular attention given to the interaction of the analysts and the diverse participants/clients of the studies which ultimately resulted in the successful solution of the problem.
Some thoughts on the use of simulation in the health services sector
Authors: Reisman Arnold
Published: January 2007

Simulation has been used in a number of modes in conducting studies for the health care industry. This paper briefly presents these usage modes and references each to more extensive write-ups of studies performed by teams which included the author of this article.
Emergency health care system models
Authors: Uyeno Dean , Vertinsky Ilan
Published: January 2007

Many models of emergency health care systems have been created, aided by the openness of the system to inspection, and the ready availability of data and research assistants. Simulation has been particularly popular due to the complex nature of models and I/0, the interest in the tails of response time distributions, and the probabilistic nature of performance criteria.In Vancouver, Canada, a number of simulation models have been created and results have been implemented. Current interest lies in multi-level ambulance models due to the relative scarcity of paramedic ambulances. Research in emergency health care systems is likely to continue
Analysis of simulation with common random numbers
Authors: Kleijnen Jack P. C.
Published: January 2007

If different random number streams are used then traditional Analysis of Variance can be applied. However, the standard errors of the estimated effects should account for heterogeneity of variance. If common random numbers are used then the quite complicated procedure proposed by Heikes et al. in 1976, may be replaced by the simple Student t-statistic combined with the so-called Bonferroni - inequality. The statistical techniques are illustrated with a simple case study.