bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthetic design of policy decisions in system dynamics models: A modal control theoretical approach
Authors: Mohapatra Pratap K. J. , Sharma Sushil K. 
Published: July 2007

AbstractResearchers and practitioners in system dynamics usually follow a trial‐and‐error process to design new policy decisions. They mainly use influence diagrams for this purpose. However, these diagrams portray the direction of influence but not its strength. Therefore, the process of policy design becomes time‐consuming, especially for beginners and those working with insufficient computer facilities. This paper presents an alternative approach for policy design using modal control theory. Policy variables are treated as control variables by delinking them from other variables. This generally leads to greatly simplified models that are free from many nonlin‐earities. Provided that this reduced system is linear and controllable, it is possible to synthetically generate control policies by modal control theory to ensure any prescribed degree of stability. These theoretical control policies then can be used to design realistic policy decisions. This approach has been used in a test example.
The use of optimization methods for policy design in a system dynamics model
Authors: Coyle R. Geoffrey 
Published: July 2007

AbstractOptimization methods have the potential to improve the processes of policy analysis and design in system dynamics models. To demonstrate the use of optimization approaches, this article applies routines developed by Keloharju to a simple model of unstable inventory dynamics. Policies derived from the optimization approach are compared with policies obtained in earlier, more intuitive analyses. The results suggest that optimization methods could significantly improve both the speed and power of policy analysis in formal models.
“The” model versus a modeling “process”
Authors: Forrester Jay W. 
Published: July 2007

AbstractFounded in the mid‐1950s, the field of system dynamics has intellectual roots reaching much further into the past. The Archives section of the Review seeks to publish material from that past which can contribute to current theory and practice. The section welcomes previously unpublished but deserving system dynamics work, classics from past system dynamics literature that should receive renewed attention, and previously published articles from other disciplines of particular significance to current system dynamicists. Contributions emphasizing the philosophy and theory of model building, validation, implementation, education, and generic structures are particularly encouraged. Submissions may range in length from notes to main articles but may be edited. Send suggested material, together with a brief introduction placing it in historical and current contexts, to John D. Sterman, System Dynamics Group, M.I.T. E40–294, Cambridge, MA 02139, U.S.A.
Dominant structure
Authors: Richardson George P. 
Published: July 2007

AbstractIn this section the System Dynamics Review presents problems having the potential to stimulate system dynamics research. Articles may address real‐world dynamic problems that could be approached fruitfully from the system dynamics perspective, or methodological problems affecting the field. A paper submitted to the Research Problems section should concisely motivate and define a problem and start a process of conceptualization or formulation that can open the way for further studies.
Methods of conceptualization
Authors: Mass Nathaniel J. 
Published: July 2007

AbstractFounded in the mid‐1950s, the field of system dynamics has intellectual roots reaching much further into the past. The Archives section of the Review seeks to publish material from that past which can contribute to current theory and practice. The section welcomes previously unpublished but deserving system dynamics work, classics from past system dynamics literature that should receive renewed attention, and previously published articles from other disciplines of particular significance to current system dynamicists. Contributions emphasizing the philosophy and theory of model building, validation, implementation, education, and generic structures are particularly encouraged. Submissions may range in length from notes to main articles but may be edited. Send suggested material, together with a brief introduction placing it in historical and current contexts, to John D. Sterman, System Dynamics Group, M.I.T. E40‐294, Cambridge, MA 02139, U.S.A.
Distribution of body fluids, plasma protein, and sodium in dogs: A system dynamics model
Authors: Hansen Jan E. , Bie Peter 
Published: July 2007

AbstractA whole‐body model of the microvascular and lymphatic transfer of fluid and plasma protein in dogs is presented. The model includes five compartments corresponding to well‐defined fluid spaces in the body: plasma, interstitial, lymphatic, erythrocyte, and cellular compartments. The transcapillary solute and solvent fluxes are computed from the Kedem‐Katchalsky and Patlak‐Bresler equations, respectively. A quantitative application of interstitial volume‐dependent exclusion of macromolecules is also included. Good agreement is found between simulated quantities and experimental data from conscious dogs in steady state and during two protocols of acute hypotonic overhydration. The model is a means of obtaining detailed quantitative descriptions of interactions between capillary and interstitial parameters that cannot be assessed experimentally.
14 “obvious truths”
Authors: Forrester Jay W. 
Published: July 2007

AbstractFounded in the mid‐1950s, the field of system dynamics has intellectual roots reaching much further into the past. The Archives section of the Review seeks to publish material from that past which can contribute to current theory and practice. The section welcomes previously unpublished but deserving system dynamics work, classics from past system dynamics literature that should receive renewed attention, and previously published articles from other disciplines of particular significance to current system dynamicists. Contributions emphasizing the philosophy and theory of model building, validation, implementation, education, and generic structures are particularly encouraged. Submissions may range in length from notes to main articles but may be edited. Send suggested material, together with a brief introduction placing it in historical and current contexts, to John D. Sterman, System Dynamics Group, M.I.T. E40‐294, Cambridge, MA 02139, U.S.A.
Chaotic structures in generic management models: Pedagogical principles and examples
Authors: Andersen David F. , Sturis Jeppe 
Published: July 2007

AbstractRecently published evidence suggests that deterministic chaos may be one of the possible modes in a number of commonly occurring structures in ecological, biological, macroeconomic, and managerial systems. Teaching bifurcations and chaos may therefore be an important part of the system dynamics curriculum. In this paper we present a catalog of structures for teaching lessons about chaos in an introductory system dynamics course. The catalog begins with a simple work force inventory oscillator and culminates with a fully chaotic structure. Techniques and principles for presenting chaos in the classroom and for formulating classroom examples are discussed.
Using system dynamics for conservation policy analysis in the Pacific Northwest
Authors: Ford Andrew , Bull Michael 
Published: July 2007

AbstractThe Bonneville Power Administration uses system dynamics to assist in its analysis of conservation policies for the Pacific Northwest electric system. This article describes the system dynamics models—the Conservation Policy Analysis Models—and explains why they are useful. After briefly describing model design and assumptions, the article gives examples of model application. One example involves simulation studies of a hypothetical policy by contractors. The second example involves Bonneville's own study of policies under consideration in the 1986 resource strategy. Key features that have made the models useful at Bonneville are noted.
Control theory heuristics for improving the behavior of economic models
Authors: Özveren Cüneyt M. , Sterman John D. 
Published: July 2007

AbstractThe usefulness of control theory techniques in economic simulations is examined. A model of the capital investment accelerator is used for illustration. It is shown that behavior approaching optimality can be achieved in a highly nonlinear system with simple heuristics based on linearization and constant state feedback with an appropriate choice of desired closed‐loop poles. Applications to real‐life situations are discussed, and suggestions are made for approaching potential problems using similar control theory techniques.
A reference approach for policy optimization in system dynamics models
Authors: Macedo Julio 
Published: July 2007

AbstractIn this article we develop a formal method, the reference approach, that can be used as a tool for policy optimization in a system dynamics model. The obtained policy is expressed in terms of feedback loops, which master the behavior of the system so that it reaches a dynamic according to the objectives of the designer.The reference approach utilizes three models: a system dynamics model, a reference model, and a control model. The first one is built using Forrester's principles. The second is a large optimization nonlinear model whose solution yields the dynamic desired by the planner. The third is a linear quadratic optimal control model with closed‐loop solution, which minimizes the gap between the observed dynamic (in the system dynamics model) and the desired dynamic expressed by the reference model.We illustrate the operation of the reference approach by using it to find the optimal policy of a well‐known system dynamics model. For this same model the best policy obtained with a heuristic approach is known. Finally, we compare the performance of these two policies.
Stochastic dynamics of instabilities in evolutionary systems
Authors: Bruckner Eberhard , Ebeling Werner , Scharnhorst Andrea 
Published: July 2007

AbstractThis article develops a modeling framework that allows a formal description of evolutionary processes in social and biological systems. An enumerable set of fields (chemical sorts, biological species, technologies, areas of scientific endeavor, and so on) is considered, each field being characterized by the number and properties of its representatives (occupying elements). By introducing probabilities for the elementary processes of spontaneous generation, identical self‐reproduction, error reproduction, death, and transition to other fields, we define a Markov process in occupation number space. At any time, only a finite set of fields is occupied, and the appearance of a representative of a field with “better” properties produces an instability in the system. The characteristic dynamics of such “innovative instabilities” are investigated by simulation. As a particular example, we consider the nonlinear growth properties associated with the emergence of new areas of scientific research.
Reference modes and the optimal shape parameter
Authors: Radzicki Michael J. 
Published: July 2007

AbstractNotes and Insights is a forum for discussion and debate about current issues in the philosophy and application of the system dynamics approach, and a marketplace for the exchange of information about current research, policy issues, and teaching experiences. Manuscripts treating material particularly suited to presentation in short form (less than 2,000 words) should be sent to Erich Zahn, Betriebswirtschaftliches Institut, Abt. IV, Universität Stuttgart, Keplerstr. 17, D‐7000 Stuttgart 1, F.R.G.
Control theory: A model of organisms
Authors: Powers William T. 
Published: July 2007

AbstractThe concepts of feedback and systems analysis are compatible with a control system model of human behavior. Control theory can contribute a model of the individual for use in larger models of social systems, in which more general feedback phenomena can be found. A review of the properties of control systems shows that they act to make their own input match internal standards or reference signals.Competent control systems create illusions of stimulus‐response causality. While stimulus‐response theory can approximate the relationship between disturbance and action, it is unable to predict the consequences of behavior. Control theory shows how consequences are maintained despite disturbances.A control theory view of individual human behavior is applicable in all sciences that deal with social systems—not as a metaphor for social control systems but as a description of the properties of the individuals who generate social phenomena.
Analyzing who gains and who loses: The case of school finance reform in new york state
Authors: Andersen David F. 
Published: July 2007

AbstractDo better models lead to better decisions? This case study assesses three computer‐based models designed to examine the distributional effects of a single school finance reform in the state of New York. The three models—a tactical simulation model, an econometric model, and a system dynamics simulation model—differ from each other in terms of five classes of assumptions applied to the analysis. Within a political decision‐making environment, the simpler tactical simulation model (essentially a data base management system) produces the most useful results because it requires few assumptions on the part of analysts. However, this class of models also fails to analyze more complex interactions within the school finance system and hence tends to lock decision makers into a myopia defined by one‐year projections. The net effect of introducing computer‐based models into the decision‐making process is to make school finance decision making more myopic. For politically based decisions about distributional impacts, the availability of more sophisticated models does not appear to lead to more sophisticated decision‐making processes.
Learner‐directed systems education: A successful example
Authors: Draper Frank , Swanson Mark 
Published: July 2007

AbstractNotes and Insights is a forum for discussion and debate about current issues in the philosophy and application of the system dynamics approach, and a marketplace for the exchange of information about current research, policy issues, and teaching experiences. Manuscripts treating material particularly suited to presentation in short form (less than 2,000 words) should be sent to Erich Zahn, Betriebswirtschaftliches Institut, Abt. IV, Universität Stuttgart, Keplerstr. 17, D‐7000 Stuttgart 1, F.R.G.
Replication and revision of a classic system dynamics model: Critique of “population control mechanisms in a primitive agricultural society”
Authors: Kampmann Christian 
Published: July 2007

AbstractFounded in the mid‐1950s, the field of system dynamics has intellectual roots reaching much further into the past. The Archives section of the Review seeks to publish material from that past which can contribute to current theory and practice. The section welcomes previously unpublished but deserving system dynamics work, classics from past system dynamics literature that should receive renewed attention, and previously published articles from other disciplines of particular significance to current system dyn‐amicists. Contributions emphasizing the philosophy and theory of model building, validation, implementation, education, and generic structures are particularly encouraged. Submissions may range in length from notes to main articles but may be edited. Send suggested material, together with a brief introduction placing it in historical and current contexts, to John D. Sterman, System Dynamics Group, MIT E40‐294, Cambridge, MA 02139, U.S.A.
On the very idea of a system dynamics model of Kuhnian science
Authors: Wittenberg Jason 
Published: July 2007

AbstractValidation strategies for models of theories have received scant attention in the system dynamics literature. Yet if system dynamics is to be an effective tool for, evaluating the dynamic consistency of theoretical systems, such strategies will need to be developed. This article illustrates how such validation might take place by analyzing an already published model of Thomas S. Kuhn's theory of scientific revolutions. The results indicate that the model, while capturing many important aspects of Kuhnian science, distorts certain fundamental features of the theory, in particular the process of paradigm change. The article concludes by discussing some of the problems associated with incorporating truly Kuhnian paradigm change into any system dynamics model.
Improving education in public schools: Innovative teachers to the rescue
Authors: Brown Gordon S. 
Published: July 2007

AbstractNotes and Insights is a forum for discussion and debate about current issues in the philosophy and application of the system dynamics approach, and a marketplace for the exchange of information about current research, policy issues, and teaching experiences. Manuscripts treating material particularly suited to presentation in short form (less than 2,000 words) should be sent to Erich Zahn, Betriebswirtschaft‐liches Institut, Abt. IV, Universität Stuttgart, Keplerstr. 17, D‐7000 Stuttgart 1, Germany.
An analysis of the cost effectiveness of U.S. energy policies to mitigate global warming
Authors: Naill Roger F. , Belanger Sharon , Klinger Adam , Petersen Eric 
Published: July 2007

AbstractThe issue of global warming has sparked debate among scientists and policymakers over the past two years. Many studies have been undertaken in the U.S. and other nations to determine the potential severity of global climate change and appropriate policy responses. The U.S. Department of Energy is now conducting one such study of energy technology and policy options to mitigate greenhouse gas emissions. The study attempts to assess the emissions reduction potential and costs of several policies, using the FOSSIL2 integrated energy model. This article focuses on the preliminary results of a subset of eight policy cases. It discusses the modeling methodology, the formulation of these policies, draft results, and some policy insights.
Are we losing one of the best features of system dynamics?
Authors: Machuca José A. D. 
Published: July 2007

AbstractNotes and Insights is a forum for discussion and debate about current issues in the philosophy and application of the system dynamics approach, and a marketplace for the exchange of information about current research, policy issues, and teaching experiences. Manuscripts treating material particularly suited to presentation in short form (less than 2,000 words) should be sent to Erich Zahn, Betriebswirtschaft‐liches Institut, Abt. IV, Universität Stuttgart, Keplerstr. 17, D‐7000 Stuttgart 1. Germany.
A system dynamics model of national cocaine prevalence
Authors: Homer Jack B. 
Published: July 2007

AbstractA system dynamics model reproduces a variety of national Indicator data reflecting cocaine use and supply over a 15‐year period and provides detailed estimates of actual underlying prevalence. Sensitivity testing clarifies the source of observed trends, such as growth in the compulsive use of crack cocaine and decline in the casual use of cocaine powder. Alternative scenarios with possible policy implications are simulated and projected for 12 years, and the results are assessed.
Introducing system dynamics in schools: The Nordic experience
Authors: Davidsen Pal I. , Bjurklo Margaretha , Wikström Hugo 
Published: July 2007

AbstractThis article describes two pilot studies of introducing system dynamics into schools in the Nordic countries. The first study describes the use of system dynamics in a high school economics class. One group of students was taught by the standard economics teaching approach; the other group, by a system dynamics approach. The second study tested the ability of 15‐ and 17‐year‐old students to understand the dynamics of social and ecological systems. The results of these pilot studies suggest that incorporating system dynamics into teaching leads to a better understanding of complex dynamic problems. A list of recommendations for designing educational systems using system dynamics was compiled.
A proposed sequence for developing systems thinking in a grades 4—12 curriculum
Authors: Draper Frank 
Published: July 2007

AbstractBarry Richmond described seven systems thinking skills needed to become a successful systems thinker. These skills are woven throughout the grades 4‐12 curriculum. The seven systems thinking skills can each be further defined by three distinct levels of competence, with an increase in cognitive capability required at each successive level. A proposed sequence is presented for the skills themselves, and suggestions are given for activities at each level within the skills. Level I activities may begin with ten‐year‐old students, but level II activities are best mastered by the senior students (about 18 years old). More research is needed to justify the proposed developmental sequence.
Using human judgment in system dynamics models of social systems
Authors: Nuthmann Conrad 
Published: July 2007

AbstractThis article addresses concerns about the validity of system dynamics models that rely on the quantification of human judgment. It reviews epistemological and semantic problems associated with scientific discourse, summarizes properties of four levels of scientific discourse (nominal, ordinal, interval, and ratio), and describes the judgmental conditions that must obtain when high‐level (interval and ratio) mathematics are applied to human judgment. Two simple system dynamics models employing continuous and discrete limens are used to illustrate the dynamic consequences of inappropriate uses of human judgment in system dynamics models. The author concludes that unless we have specific evidence that the judgmental phenomena we are modeling behave according to additive, multiplicative, or averaging models, we can not assume we are dealing with anything other than ordinal phenomena.
Skill formation and its impact on the adaptation process of new production systems
Authors: Diawati Lucia , Kawashima Hironao , Hayashi Yoshio 
Published: July 2007

AbstractA system dynamics model is developed to facilitate the study of a firm's introduction of a new, more technologically sophisticated production facility. The system must adapt in three areas: production facilities, labor, and management. Emphasizing industrial situations commonly encountered by producers in developing countries, this study focuses on the ways management efforts and the learning process influence the development of labor expertise.The firm's performance is found to move through three phases of adaptation: fluctuations, growth, and adjustment to external change. Three approaches to improving the firm's performance are investigated: better preparation for the new technology, quicker initiatives to develop labor skills, and better‐designed skill training. Comparative simulations show that better skill formation yields better system performance than faster response alone because of its ability to accelerate the development of new skills. However, better preparation can reduce the length of the initial unstable phase in the adaptation process and produce higher system performance when combined with the other skill formation policies.