bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation as an Aid To Understanding Cognitive Processes
Authors: Newsted Peter R. 
Published: March 2008

Computer simulation of cognitive processes requires con structing an explicit model of human thinking behavior in the form of a computer program. Such a program cannot avoid being explicit and unambiguous. Thus it serves as a hypothesis to be tested against the corresponding human behavior. Models that don't "work" suggest questions to ask. Recent work in simulating cognition suggests that the basic elements in cognitive processes are attention, conscious ness, and memory. In this paper, a hypothesis is presented describing probable interactions among these elements for a simple cognitive process. To facilitate simulation a paradigm is presented which characterizes experimenter subject interactions in such a way as to allow an investiga tor to more easily attempt a simulation. A sample simu lation of concept identification behavior is included to illustrate the use. of this paradigm.
The course of French society (1955-73) — a simulation
Authors: Rastogi P.N. 
Published: March 2008

This paper analyzes the course of French society in terms of the time path of a set of variables: exoge nous politico-military pressure, economic growth, unemployment, price rise, population growth, ethnic tension, public unrest, administrative effectiveness, expectations of socii, and an overall measure of societal viability termed Government Stability (Z or GS). The variables reflect the performance of interacting societal institutions that together constitute a complex adaptive total-society system. Government operates as the regulatory subsystem of society. The values of the variables during a given period represent the state of the system. They are ob tained through a simulation algorithm which simu- Zates a societal flow graph representing the pattern of internal system dynamics. The extension of simulation to past and future periods permits retrodictive confirmation and predictive inference. The correspondence and consistency of the generated results with the reported and available data makes possible the validation of the analysis. The simu lation algorithm, which is applicable to all socie tal systems, is here applied to chart the course of French society for the two decades from 1955 to 1973. Values of economic growth, price rise, unemployment, and change of government generated by simulation are directly confirmable from known empirical facts. The confirmation of qualitative variables like ethnic tension, administrative effectiveness, and expectations of socii as gener ated by the model is, however, based on inference. They conform to the broad empirical pattern as outlined in the secondary sources of data.
Similarity between computer control systems and community planning
Authors: Light Richard A. , Johnson R. Curtis 
Published: March 2008

The planning of a community's development and opera tions, whether for a small town or an international project, requires the allocation of resources to various areas of endeavor. These resources can best be allocated if a reasonably accurate estimate is made of the needs for corrective action and the effectiveness of it as a function of the type and amount of expenditure. For example, an estimate may be made of the amount of pollution and social conflict which may develop and of the effectiveness of various physical and human countermeasures (sewage disposal facilities, air pollution control, police, hospitals, etc.); on this basis a reasonable allocation may be made. Such a procedure forces one to establish value systems in order to assess social costs on a basis compatible with real costs. This is difficult. Few planners understand the philosophical and long- term implications of their actions. The approach adopted in this paper bears great similarity to optimal process control by computer, but it cannot solve problems unless suitable value systems can be established. Even when values cannot be adequately established, however, this approach to examining community problems allows decision- makers to better understand the implications of their actions. This approach helps educators to better plan programs which differ from the tradi tionally narrow engineering curricula and to intro duce the concept that technical tools and techniques have important applications in politics and philosophy.
A generalized model for simulating lake ecosystems
Authors: Park Richard A. 
Published: March 2008

CLEAN, a generalized lake-ecosystem model with strong ecological realism, has been developed in response to one aspect of the growing need for models suitable for helping man to manage his environment. The model currently consists of twenty-eight ordinary differ ential equations which represent approximately six teen compartments, including attached aquatic plants, phytoplankton, zooplankton, bottom-dwelling aquatic insects, fish, suspended organic matter, decomposers, sediments, and nutrients. These equations can be linked in any meaningful combination to simulate a given point in a lake (a separate model for lake cir culation is available to represent spatial variations and to couple simulations of different regions of the lake). Subprogram functions exist for each principal physiological and ecological process, and a submodel for lake water balance is presently being implemented. The program is written in FORTRAN for UNIVAC and IBM time-sharing systems. The model has provided intuitionally realistic simu lations and has given us insight into the effects of nutrient enrichment on the functioning of the lake ecosystem as a whole. Sensitivity analysis has in dicated priorities for further studies to obtain more precise estimates of parameters. Also, evalua tion of the logic and organization of the model by experimenting with it are providing information to use in planning new experimental approaches. CLEAN is presently being tested using data from Lake George, New York, and Lake Wingra. Wisconsin.
Gasp IV urban model of cadmium flow
Authors: Talavage Joseph J. , Triplett Mark 
Published: March 2008

The 60-square-mile region of extreme northwest Indiana, which includes the cities of Gary and East Chicago, is a highly urbanized and industrialized area. Pollution data over the region show high levels of cadmium, a toxic metal. There are several hundred sources of cadmium in the area, and the impact of each type of source is unclear. An accurate representation of the flow of cadmium would make it possible to structure a reasonable and efficient policy for controlling cadmium pollution. This paper describes a GASP IV computer model for that flow. The basic model is an aggregate continuous model which displays the time behavior of cadmium levels in each of nineteen compartments over a two-year period. This aggregate model raises several ques tions regarding the effects of discrete events such as rainfall. Since the GASP IV language is capable of combined continuous-discrete simulation, these new factors are easily incorporated into the model. Results of the simulation show the relative impact of the various types of sources and provide some insight into control policies. A continuous model was first constructed. Then modifications based on real-world data were implemented as discrete events. The successive forms of the model proved useful for studying at least two of the characteristics of cadmium flow in an urban ecosystem.
Diogenes revisited -the search for a valid model
Authors: House Peter W. 
Published: March 2008

PETER W. HOUSE has, since November of 1971, been with the U.S. Environmental Protection Agency where he is assistant director of the Washington Environ mental Research Center in the office of Research and Development. He is the former president of Envirometrics, Inc. During his four and one-half years at the Washington Center for Metropolitan Studies and Envirometrics (April 1967-October 1971) he directed the development of three urban operation al simulation models, including the CITY models and the RIVER BASIN MODEL. Dr. House received his master's degree in economics from Clark University and thereafter went to work for the U.S. Department of Agriculture as a research economist in the Economic Research Service (ERS). During his tenure at ERS (February 1960-March 1967) he performed a number of studies concerning suburban/ farmland and preferential tax assessment, and was selected to attend Cornell University to complete work on his doctorate. Currently, at EPA, Dr. House and his staff conduct studies and develop forecasts which can move EPA to a position of being able not only to enhance the environment but also to provide for long-term preven tion of pollutants. He is project leader of the team responsible for development of the Strategic Environmental Assessment System (SEAS). Two books under his authorship have recently been published: The Urban Environmental System: Modeling for Research, Policy-Making and Education, published by Sage Publications: and, with Edward R. Williams, The State of the System (SOS) Model, published by EPA.
CHINA 1: a model of growth for the People's Republic of China
Authors: Brinton William , Rosenberg Gerald H. , Wolfe John 
Published: March 2008

This paper describes a simulation model of population growth in the People's Republic of China from 1953 to 2103. Our model, CHINA1, is based on the WORLD3 model of D. L. Meadows et al., and thus it analyses population growth in the context of a large, inter related economic and environmental system. It assumes that China will continue her present policy of material self-sufficiency. Model simulation runs based on current trends in China show continued population growth well into the twenty-first century, despite a falling birth rate. A precipitous decline in population then ensues due to resource depletion, collapse of the industrial sector, and mass starva tion. Policies designed to avert such an outcome are tested in the model. The simulation indicates that a successful policy must include all of the following: 1. The family size norm declining to two children by 1985 2. Industrial output per capita stabilizing at the level projected for 1990 3. Dependency on nonrenewable resources lessening over the long-run.
Correlated simulation experiments
Authors: Fishman George S. 
Published: March 2008

This paper studies the effects of using correlated random-number streams in replications of a simula tion experiment in which output is to be related to input by linear or quadratic response surfaces. For the linear case, it is shown that either positively or negatively correlated streams produce a smaller generalized variance for the least-squares estimates than occur when the streams are independent. Al though the prediction variance is small with nega tively correlated streams, positively correlated streams produce a smaller variance for the estimated slope. In the quadratic case it is shown that of twenty- seven possible input correlation designs only six guarantee a smaller generalized variance. Only one of these produces a smaller prediction variance. However, no plan will guarantee a smaller slope variance. In the quadratic case one often wants the slope variance to be as small as possible since the objective of the study may be to determine where the maximum or minimum response occurs in terms of the input.
Analysis of Harvesting, Loading, and Transportation of Farm Grains
Authors: Baker C.H. , Horrocks R.D. , Braaten M. 
Published: March 2008

Selecting harvesting equipment for greatest capacity is often a compromise between excess capacity for some years and too limited capacity for others. We expected that the harvester capacity producing the highest long-run profit would also produce a higher year-to-year variability of profit than would a larger-capacity machine which would also produce a lower long-run profit. To balance the long-run profit against the higher risk, the decision- maker needs a measure of the risk involved. Simulating production systems is an effective way to develop decision-making information. Trans forming observations of the behavior of real-world systems into the kind of information which can form a basis for decisions is a challenging task in agri cultural-production systems. This paper discusses a harvesting and transportation system simulator that can help the decision-maker to determine the size and amount of machinery needed to complete a har vesting operation in a given amount of time. Inputs to the model include the size and number of fields and their distance from a farm elevator, elevator and storage-bin sizes, combine and truck sizes, and certain timeliness factors such as dryer time and trips per day to market. The simulator was tested and found to be logically correct.
Evaluating analog-to-digital converters
Authors: Polge R.J. , Bhagavan B.K. , Callas L. 
Published: March 2008

Dynamic performance of an A/D converter cannot be assessed by conventional tests since they employ slowly varying inputs. In this paper, a digital computer procedure is developed to determine the presence and extent of errors due to time jitter, nonlinearity, gain, quantization, and locked bits. The procedure is based on discrete power-spectrum analysis of recorded outputs of the A/D converter using a weighted or nonweighted sine wave input. In the latter case, a discrete weighting of the recorded output must be performed before power-spectrum analysis. Outside of the narrow band containing the signal spectrum, the power spectrum corresponds to the errors in the A/D converter. Error models are suggested and implemented in a simulation program which is executed to show the power spectra for various combinations of errors. On this basis an A/D converter evaluation procedure is proposed and illustrated by an example.
Corporate simulation models: a survey
Authors: Naylor Thomas H. , Jeffress Charles 
Published: March 2008

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 recom mendations for improving the effectiveness of cor porate simulation models. First, corporate models should be made more user-oriented. Second, more attention needs to be given to the production acti vities of firms. Third, the possibility of inte grating 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 con sidered. Sixth, greater emphasis should be placed on the "politics" of corporate model building.
TACL - a timeshared hybrid system for control laboratories
Authors: Volz Richard A. , Aravena Jorge 
Published: March 2008

A generalized control-system model encompassing a wide variety of systems has been programmed on the analog portion of a hybrid computation system. Five terminals with storage oscilloscopes are con nected to the hybrid computer and are serviced on a round-robin basis. The generalized system can be configured in milliseconds to a specific problem by setting the values of the digital coefficient units and switches of the analog system. A library of specific problems is kept on the system's digital disk. Students use the system by referencing a problem in the library and entering parameter values to define the problem from their terminals. The per-solution time varies with the time scale seZect ed, but averages around a few hundred milliseconds. A user-oriented compiler helps the instructor define new problems to be added. Digital values are assigned by the student to select ed parameters of specific problems, and families of curves representing system performance as a function of control settings may be displayed on the student's terminal. The terminals also display digital data and alphanumerical information.
Simulation of cell-cycle kinetics based on a multicompartmental model
Authors: Jansson Birger 
Published: March 2008

Biological cells, healthy or malignant, perform in most respects similar activities: (a) They proliferate by growing and maturing and, after reaching a certain level of maturation, they divide into daughter cells. (b) They differentiate by changing irreversibly to new types of cells. (c) They compete by participating in ecological struggles with other cells that share the same ecological niche. Through the principle of com petitive exclusion, slower-dividing cells may be eradicated from a mixture of cells. This paper presents a mathematical model of the above processes and describes a computer simulation which includes the effects of chemotherapy or radiation therapy on a system consisting of healthy and malig nant cells. The simulation develops qualitatively and quantitively the kinetic properties during treat ment of the mixture of the two types of cells in tissues and shows how the favorable protocols for treatment can be found. Such knowledge can, among other things, be used to devise good strategies for the treatment of cancer by radiation or chemotherapy and to increase the efficiency of research in their use. The example described is a simplified one in which only two types of cells are considered, but the simu lation model can be applied to much more complex and realistic situations.
Digital computation of frequency response
Authors: Mitchell E. Eugene , Olsen Charles F. 
Published: March 2008

This paper describes three algorithms for the digital computation of the frequency response of linear sys tems and discusses their advantages and disadvantages. The third method presented is a novel one which applies the standard polynominal quadratic synthetic division algorithm in a unique way to the problem. The method allows the forward and feedback-path transfer functions to be inputted in any form; it computes the open-loop and closed-loop frequency responses in one pass; and, most importantly, it does not require numerical factoring at any point. The method is easy to use and appears to run effi ciently, particularly for high-order systems. The paper concludes with FORTRAN and BASIC programs which implement the algorithm of Method Three.
HAPS, a Handy Analog Programming System
Authors: Højberg K. Søe 
Published: March 2008

HAPS (Hybrid Analog Programming System) is an analog compiler that can be run on a minicomputer in an interactive mode. Essentially HAPS is written in FORTRAN. The equations to be programmed for an ana log computer are read in by using a FORTRAN-like notation. The input must contain maximum and minimum values for the variables. The output file includes potentiometer coefficients and static-test 'measuring values.' The file format is fitted to an automatic potentiometer-setting and static-test program. Patch instructions are printed by HAPS. The article describes the principles of HAPS and emphasizes the limitations HAPS puts on equation structure, types of computing circuit, scaling, and static testing.
Practical and ethical issues of development in traditional societies
Authors: Picardi Anthony C. 
Published: March 2008

The results of a system dynamics model of pastoralism in the sahel region of West Africa are presented and analyzed, and the conclusion is drawn that not all the desired objectives for developing the region can be attained simultaneously. The fact that practical tradeoffs exist leads to a consideration of some ethical issues which may enter into the choice of alternative development policies. The principal data source for this study is the sahel and subdesert region of Niger north of Tahoua, where herdsmen practice traditional animal husbandry, seeking pastures in the north during the rainy sea son and descending south toward the agricultural zones in the dry season. The probable effects of aid efforts in the past were analyzed, with the con clusion that if they had any effect at all, it was to increase the severity of the drought disaster in both ecological and human terms. A set of seven desirable long-term objectives is defined and policies to achieve them are simulated. The simulation results indicate definite tradeoffs among the desired objectives. The existence of mutually exclusive attainable objectives leads to a consideration of the ethical issues involved in the choice of alternate development policies. This case study serves as an example of how system dynamics may be used to reduce complex social prob- Zems to a set of relevant ethical questions.
Hybrid simulation- key to successful flight-test program
Authors: Driscoll Thomas R. , Eckenroth Howard F. 
Published: March 2008

The purpose of this paper is to focus on the applica tion of modern analog- and hybrid-computer analysis techniques for both the planning of control test vehicle (CTV) flights, which was instrumental to the success of the flights, and the verification of the design of the missile. The hybrid simulation had features generally not available in existing programs and reflected major advancements in simulation and modeling technology. It permitted tolerances to be analyzed by use of either the individual parameter variation or the Monte Carlo approach. Error sources were modeled as they existed in the actual hardware. The SAM-D hybrid simulation program was designed to use automatic data-reduction techniques to provide the analyst with detailed technical data on both nominal and toleranced flight performance. Special routines allowed statistical predictions to be made on all important parameters within the system to en sure that all requirements were met under toleranced conditions. The use of a detailed hybrid simulation, including nominal and comprehensive tolerance models, and of automatic data-reduction techniques, provided a high degree of confidence in a successful flight under all possible military flight conditions. The simulation program described herein was supported by a comprehensive wind-tunnel test program and other subsystem ground tests to provide input data of high quality compatible with the extent of the detailed simulation. The value of this approach to modern flight-vehicle design was confirmed by the close agreement between predicted and flight-test data. Thus the simulation not only enhanced the success of the flight tests, but also enabled the simulation to be used for evaluating system performance under conditions not covered by flight tests.