Interactive Simulation Model Research Articles

An Interactive Stochastic Simulation Model of a Health Service District

An Interactive Stochastic Simulation Model of a Health Service District

An interactive stochastic simulation model of a health service district.

This paper describes the role and structure of a model of a U.K. health district and its extensive use in the U.K. as a training aid in developing corporate planning skills.

Modeling and analysis of biomass production systems

BIOMET is an interactive simulation model that is used to analyze specific biomass and methane production systems. The system model is composed of crop growth models, harvesting, transportation, conversion and economic submodels. By use of menus the users can configure the structure and set selected parameters of the system to analyze the effects of variables within the component models. For example, simulations of a water hyacinth system resulted in yields of 63, 48 and 37 Mg ha −1 year −1 for different harvest schedules. For Napiergrass, unit methane costs were $3·04, $2·86 and $2·98 for various yields of biomass.

Energetic electron precipitation due to gyroresonant interactions in the magnetosphere Involving coherent VLF waves with slowly varying frequency

A test particle simulation model (Inan et al., 1982) of the gyroresonance wave‐particle interaction in the magnetosphere is extended to study the transient particle precipitation fluxes induced by various coherent VLF waves with slowly varying frequency propagating along the earth's magnetic field lines. For moderate wave intensities (Bw ≤ 10 pT at L = 4) a comparison between input signals with linearly rising and falling frequencies shows that they induce the same amount of precipitated particle energy deposition. However, when the wave growth near the principal interaction region is considered, the precipitation induced by a riser is considerably higher than that induced by a faller. The effect of the frequency‐time slope (df/dt) of the input signal on the induced precipitation energy flux is found to be small. Our results indicate, however, that the precipitation energy flux depends strongly on the falloff in energy of the trapped particle distribution function. The model is applied for computing the transient precipitation energy fluxes induced by a triggered rising emission, a hooklike signal and a one‐hop whistler. The total precipitated energy deposition for these various signals is found to be comparable to that induced by a linear ramp having the same input wave energy density.

SKIDLOG--An Interactive Skidding Model

Abstract SKIDLOG is a deterministic "what-if?" interactive computer simulation model designed to evaluate the potential performance of a 4-wheel-drive articulated log skidder under a variety of assumptions and constraints. The model considers the effect of tire size, soil strength, tree size and load geometry, slope, and skidder size, type, horsepower, and speed to determine the ability of a skidder to move a load of logs.

MANAGE - An interactive simulation model for evaluating the effects of management structure on organization performance

This research reports on progress to date in developing a com puterized simulation-optimization model of the general man agement structure of a firm. This model, called MANAGE, of fers a framework wherein the profit performance of a company can be simulated and assessed under a variety of structural con figurations. MANAGE also incorporates certain behavioral parameters that impact upon successful communication within corporate organizations. The paper describes the general framework of the model; the manner in which various struc tural, behavioral, and economic variables are incorporated into the model or can be set as desired by the user; and the nature of the outputs that are produced. Also described is the man ner in which MANAGE generates profit solutions under various combinations of behavioral, hierarchical, and economic con ditions and compares them with traditional optimal economic results. The paper concludes with a brief discussion of the potential applications of MANAGE.

An Interactive Model of Soil Mixing

ABSTRACT AN interactive computer simulation model for a continuous soil mixing operation has been developed which can be used as a research, developmental, and an analysis tool. The model is developed with the understanding that a user may not be aware of programing and does not particularly care to or have time to learn its intricacies. An example problem is also included to explain the type of results obtained and how to interactively maximize machine and labor outputs.

Simulation: An Operational Planning Device for the Bell System

One of the many important tasks facing Bell System planners in setting up the fully separated Bell subsidiary involves determining efficient configurations for regional trouble-reporting operations. This paper describes a user-friendly, interactive (GPSS) simulation model developed to assist operational planners and discusses some of the current and anticipated applications of the model.

Dynamic Simulation of Radially Oriented Permanent Magnet-Type Electronically Operated Synchronous Machines with Parameters Obtained from Finite Element Field Solutions

A dynamic model for simulation of the transient interaction between radially oriented permanent magnet-type synchronous machines and their corresponding transistorized current source power conditioners is presented. Some key machine parameters used in this dynamic model were obtained from finite element field solutions. This dynamic model was used to obtain the transient interaction between a 15-hp samarium cobalt radially oriented permanent magnet electronically operated synchronous machine and its corresponding power conditioner. This machine was constructed for electric vehicle propulsion. Excellent correlation between various digitally simulated and actual test current and voltage waveforms, in various branches of the machine-conditioner network, has been achieved. These results are given. This modeling approach is applied to machines during the design stage, where the finite element modeling is the only way to obtain the necessary machine parameters for dynamic simulation. It is shown how such a combination of the computer-aided design tools can help in prevention of design mis-judgements that can prove costly to remedy once the hardware is in place. This is done through an actual design example of an additional machine being manufactured for electric propulsion applications.

A methodology for achieving the aims and objectives of theForum Humanum:The approach of the Venezuelan group

The Venezuelan group of the Forum Humanum has adopted a procedural approach which might serve as a standard methodology for all the research centers in the Forum Humanum. This approach involves utilization of the Delphi method, cross‐impact analysis, systems impact analysis, and scenario construction. The findings of these methods as they emerge from the various research centers are to be combined into a simulation model of global interactions.

An Interactive Simulation Model of Batchwise, Chemical Production – A Tool to Improve the Communication Between the Plant Operators and the Production Process

The development of an interactive simulation model for batchwise, chemical production is discussed. The model consists of a plant submodel written in GPSS and a control centre submodel written in Fortran. The design of the plant submodel is based on developed methodologies for systematic descriptions of the production line and of the discontinuous production dynamics, and closely reflects the real control system. The control centre submodel consists of a number of subroutines, each corresponding to a particular section of the real control panel. The developed design principles were successfully tested by experienced plant operators.

Mr. Babbage, the difference engine, and the problem of notation: An account of the origin of recursiveness and conditionals in computer programming

Contrary to the opinion of Lady Lovelace and others the origin of programmed conditionals and recursiveness may be traced back to the Difference Engine of Charles Babbage. To prove this is the aim of the present inquiry which is supported by contemporary quotations, based on a rather extensive historical research, and by computational experiments performed on an interactive simulation model in APL of the Difference Engine. It is attempted in the article to document the use of APL in such a manner that the few figures of particular interest for readers knowlegeable of APL, may be skipped without any general loss of meaning by the common reader.

Visual Interactive Simulation Using a Mini-Computer

Visual Interactive Simulation models have, to date, only been run on mainframe time-sharing systems. This note presents details of the first implementation of the technique on a dedicated mini-computer.

A stochastic CAI model for assisting in the design of football strategy

This article describes a FORTRAN based interactive stochastic simulation model intended to assist collegiate football strategists in the design and evaluation of various offensive strategies. The model does exist and has been partially validated.

Optimal Pesticide Application for Controlling the Boll Weevil on Cotton

AbstractA simulation model of interaction between the boll weevil insect subsystem and the cotton plant subsystem is presented. Field experiments provide the basis for validation of the model. Pesticide control scheme is introduced, and optimal control is achieved by using a numerical nonlinear dynamic optimization technique. Results of sensitivity analysis with respect to price changes are provided. Optimal policy for a single producer calls for three applications. Timing is robust, but dosage levels are sensitive to price changes.

Operational Research and Organization Development

A large research program concerned with the contribution of operational research (OR) to the design of organizations led indirectly to an OR project concerned with constructing a man-computer interactive simulation model for a department in local government. The simulation model was to map the decision-making activities of the department and their influence on critical features of the environment which were of interest. The most difficult part of this project was the application of new methodologies for eliciting the values, norms, objectives, goals, and views of the environment in order that the model of decision-making could be constructed. The key concepts underlying the method were drawn from the psychology of personal constructs and the sociology of defining situations. The data analysis resulting from an application of these concepts led to the organization wishing to become involved in an organization development (OD) exercise. How this request evolved, the conceptual basis of the OR, and some of the repercussions of the OD work on effective OR are what the paper is about.

Interfacing Large Interactive Systems Models and the User: The Case of a Beef Cattle Enterprise Model for Decision Assistance

The interface between a large interactive simulation model and the user is discussed along with and in the context of a general beef cattle enterprise model designed to be used as a decision assistance tool. Emphasis in this model is on the cow/calf land extensive form of operation. A highly disaggregated herd population model allows full exploration of population dynamics. Using total digestible nutrients (TDN) as the basic feed quality description, and net energy for growth and maintenance where possible, the nutrient impact component predicts rates of weight gain and reproductive dynamics as a function of feed intake. Forage growth is modeled as a function of the exogenous variables of solar radiation, temperature, and rainfall. As an enterprise model, attention is focused on the planning and management decisionmaking needs of decisionmakers. The model is viewed as a tool for exploration of alternative strategies to assist the traditional and intuitive method of management. The model is interactive, with straightforward decisions made using endogenous decision rules, while complex decisions require the input of the model user. The design of the interface between the model and the user to allow effective interaction is discussed in detail. A demonstration of the model's capability is given using a project investment planning example.

MAPS

By approaching two and three-dimensional problems from the spatial viewpoint taken by the geographic sciences, the <u>M</u>ulti-dimensional <u>A</u>nalysis <u>P</u>rocessing <u>S</u>ystem (MAPS) is able to achieve high efficiency and large capacity in many types of interactive graphics, simulation modeling, and image processing. Spatial relationships are presented by means of color images, rather than line drawings, facilitating interpretation and display of complex, continuous data sets. By integrating data base and CRT refresh storage into a single subsystem, MAPS is able to make extensive use of analog devices. This analog processing permits complex image transformations to be done at high speed and low cost. User interface is handled by the system-control minicomputer, and is designed to allow MAPS to serve as a powerful "perception amplifier", even for nontechnical users.

AN ANALYSIS OF FINANCIAL DECISIONS FOR RETIREMENT: AN EXPLORATION OF SEVERAL METHODOLOGIES WHERE THERE IS UNCERTAINTY OF INVESTMENT RETURNS AND MORTALITY

THIS THESIS DEALS with three studies of methodological approaches to the decision problem concerning provision for retirement. The first study is made of the decision problem during the accumulation period, the working years before retirement. Background investigations are made concerning the institutional and investment environment within which the decisions and investment growth occur. Based on these investigations, a probabalistic simulation model of the accumulation period up to retirement is constructed with various elementssome beyond the decision maker's control and others which are decision variables. Experimental evidence with several subjects is discussed. One major conclusion is that within reasonably broad limits decision makers can select appropriate strategies by direct observation of the probability distributions of consequences, i.e., without more complete decision analysis involving explicit assessment of utility and backward induction. Secondly, it is felt that the summary statistics of aggregate wealth at retirement might be too brief since what the decision maker is really interested in is the standard of living he will enjoy during the retirement period, i.e., consumption levels. The second study investigates the institutional, investment and mortality environments during the period beyond the date of retirement in order to develop a simulation model which replicates the essential elements of the retirement period. Again several subjects are exposed to an interactive computer simulation model and evidence is gathered. From the experimental studies it is found that there is considerable educational value in such a model to the subjects. Individuals tend to prefer a specific annuity option; probably spend too little in the early years of retirement; and should probably spend more out of capital in these early years. The model is found to be cumbersome for analytical purposes but quite useful for educational uses. Suggestions are made for improving the model. As part of the second study utilities for wealth at retirement are assessed for several decision makers. Finally, the third, more theoretical study examines the structure of the utility for consumption during the retirement period when the lifetimes of both the decision maker and spouse, as well as investment returns, are uncertain. The theoretical underpinnings of the structure are developed and assessment techniques are investigated. Since the assessment task can be enormous there is a discussion of means by which the task can be simplified.