bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deterministic chaos in the beer production‐distribution model
Authors: Mosekilde Erik , Larsen Erik Reimer 
Published: July 2007

AbstractDepending upon the assumed ordering policy, the classical Beer Distribution Model shows a great variety of complex dynamic behaviors, including limit cycle oscillations of different periodicities and deterministic chaos. This article presents an overview of these phenomena. The ordering policy is expressed in terms of two parameters that measure the fraction of the supply line and the fraction of the anticipated shipments accounted for in the placement of orders. Our results indicate that, in certain regions of parameter space, any neighborhood to a given solution will contain qualitatively different solutions. The complexity of the system is revealed in two‐ and three‐dimensional reconstructions of chaotic attractors as well as in Poincaré sections obtained from such reconstructions.
Deterministic chaos in models of human behavior: Methodological issues and experimental results
Authors: Sterman John D. 
Published: July 2007

AbstractRecent work has shown that several well‐known models in the system dynamics literature contain previously unsuspected regimes of deterministic chaos. Two of the most extensively analyzed are Sterman's model of the economic long wave and the production‐distribution model of the Beer Distribution Game. The significance of these theoretical developments hinges on whether the chaotic regimes lie in the realistic region of parameter space. There are also questions regarding the descriptive accuracy of models of human systems that exhibit chaos. Because of data limitations and the inability to conduct controlled experiments, empirical studies at the aggregate level are not likely to resolve these questions.An alternative approach is based on laboratory experiments in which models provide a simulated environment for the study of human decisionmaking behavior. Recently, laboratory experiments have been conducted to analyze decision‐making behavior in the longwave model and the Beer Distribution Game. This article describes these experiments and shows that the behavior of the subjects is explained well with a simple heuristic long used in system dynamics modeling and well grounded in behavioral decision theory. The parameters of the proposed decision rule are estimated econometrically for each subject. The parameters that characterize a significant minority of the subjects are shown to produce chaos. This direct experimental evidence that chaos can be produced by the decision‐xnaking behavior of real people has important implications for the formulation, analysis, and testing of models of human behavior.
Sustaining economic growth with a nonrenewable natural resource: The case of oil‐dependent Indonesia
Authors: Arif M. Tasrif , Saeed Khalid 
Published: July 2007

AbstractThis study uses a system dynamics model based on an integration of micro‐and macroeconomic theories to understand economic growth with a nonrenewable natural resource. The case of oil‐dependent Indonesia is used as an empirical reference for the study. Long‐run growth patterns resulting from various intuitively appealing development policies are analyzed, and an attempt is made to identify the best policy set for attaining a sustainable growth pattern. The study shows that influencing factor prices to facilitate adoption of capital‐intensive technologies accelerates development and is a key policy for sustaining growth in the long run.
Simplification and understanding of models
Authors: Eberlein Robert L. 
Published: July 2007

AbstractThe theory of model simplification is presented as a means of increasing model understanding. Simplification is based on a selection of the behavior modes defined by the linearized representation of the model and results in a smaller and more easily understood model. To allow understanding, the variables in the simplified model must be easy to interpret relative to those in the original model. This interpretation is complete in an exact simplification, a concept used to derive measures of the importance of different variables in generating selected behavior modes. These measures are used to select which variables to retain and which to omit in forming the simplified model. Issues in the application to nonlinear models are considered, and software that facilitates model simplification is discussed.
System dynamics meets the press
Authors: Meadows Donella H. 
Published: July 2007

AbstractThe shared paradigms of society, the public discourse, the deepest assumptions about how the world works, these are the ultimate sources of system structure and the primary obstacles to structural change. The reigning paradigms of the western world are astonishingly unsystematic, and they give rise to badly structured, difficult‐to‐manage large‐scale social systems with persistent problems, such as pollution, poverty, and war. One way to contribute to the restructuring of those systems is to bring more clear, accurate, and inclusive systems concepts into the public discourse—to communicate systems insights regularly and powerfully through the press.Even the simplest ideas of system dynamics—stocks, flows, positive and negative feedback, the effect of delays, the importance of nonlinearity—can help to clarify public discussion and improve public policy. They must be communicated without jargon, without mathematics, without loop diagrams. That can be done, and the best partners in doing it are those who are already professionals in the art of public communication—the members of the press.
Projecting the future value of a variable in a system dynamics model
Authors: Clark Rolf , Omholt Clark A. 
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.
Software productivity: Potential, actual, and perceived
Authors: Abdel‐Hamid Tarek K. , Madnick Stuart 
Published: July 2007

AbstractIn this article, we investigate the dynamics of software development productivity throughout the software development lifecycle. Our investigation discerns three forms of productivity, namely, potential, actual, and perceived. This conceptual dissection of productivity provides a useful lens for focusing on two distinct sets of managerial concerns: losses in the efficiency of software production, and losses in the effectiveness of managerial control. Losses in production efficiency stem from faulty processes associated with motivation and communication and lead to a gap between potential productivity and actual productivity. Losses in the effectiveness of managerial control arise, particularly in the early stages of a software project, from the discrepancy between what management perceives productivity to be and what it actually is.
Rangelands destruction under population growth: The case of Iran
Authors: Mashayekhi Ali Naghi 
Published: July 2007

AbstractAs population and income per capita grow in a developing country like Iran, demand for meat increases but a potential nutrition crisis also arises. Meat production becomes more profitable, and the number of sheep or other meat‐producing animals in the country rises. Growth of the sheep population increases the demand for fodder, which is obtained from two major domestic sources: rangelands and farmlands. However, as a result of population growth in the country, the demand for non‐meat food, which is produced on the farmlands, also rises and increases the demand for the farmlands themselves. Since cultivable land is limited, the price of farmlands increases and makes farm hay production more expensive. As a result, the pressure on the rangelands to feed the growing sheep population rises. The sheep population in the rangelands finally surpasses their carrying capacity, causing rangelands destruction and a collapse in range grass production. Eventually, the domestic food supply falls sharply, producing a serious crisis in meat supply and nutrition of the human population. To prevent such a crisis, different policy alternatives are examined. The key to a successful policy is identified to be balancing the number of sheep in the rangelands with the production capacity of the rangelands. In addition, lower population growth and higher investment in the rangelands can keep domestic meat production per capita at a higher level.
A structured approach to knowledge elicitation in conceptual model building
Authors: Vennix Jac A. M. , Gubbels Jan W. , Post Doeke , Poppen Henk J. 
Published: July 2007

AbstractPolicy‐oriented modeling demands client involvement in the model‐building process. This poses a knowledge elicitation problem, i.e., how to obtain the necessary knowledge from a group of people. Traditionally, interviews and freely interacting groups have been employed most frequently for this purpose. In this article, we present an approach to knowledge elicitation that employs a combination of different techniques to arrive at a conceptual model of a regional health care system. The adopted approach is sufficiently general to be employed in other model development processes as well.
The impact of exchange rate policy on inflation rate in an oil‐exporting economy
Authors: Mashayekhi Ali Naghi 
Published: July 2007

AbstractExchange rate policy is one of the most important economic policies to be decided by governments. In countries (like the OPEC countries) where a major part of government revenues is in the form of foreign exchange earned from exports of nationalized products and minerals, the exchange rate influences government finance and budgets directly. This paper describes the structure and behavior of a model formulated to explore fixed and floating exchange rate policies in such an economy. Model‐based policy analyses show that when the government of such an economy faces a decline in foreign exchange revenues, a fixed formal exchange rate intensifies inflationary pressures and leads to a higher market exchange rate. In addition, under a fixed exchange rate policy, a decline in foreign exchange revenues results in a drastic fall of the government budget at fixed prices, while with a floating rate policy, such an erosion of government purchasing power does not occur.
Dynamics of commodity taxation: An example of an energy tax
Authors: Wirl Franz 
Published: July 2007

AbstractCommodity taxation represents one means of raising public revenues. Recently, this proposal has received considerable support from environmentalists, who argue that commodity taxation, besides raising revenues, will have the positive effect of controlling externalities and limiting negative environmental side‐effects of commodity production. This article considers the dynamics of such taxation when taxpayers must solve a costly and intertemporal adjustment problem. Applying recent data from Austria, the author analytically and quantitatively explores the implications of sluggish consumption on the design of a revenue‐stable tax policy. If demand is elastic, the stability of such a tax regime is questionable for theoretical reasons. In practice, its stability may be questionable even if demand is inelastic.
Qualitative simulation and system dynamics
Authors: Dolado José Javier 
Published: July 2007

AbstractThis article explores some requirements for applying qualitative simulation algorithms to system dynamics models. The field of qualitative simulation lacks a specific procedure for modeling systems (subjects of its models are generally physical systems). Bringing together qualitative simulation techniques and system dynamics modeling techniques could benefit both fields. The structural correctness of system dynamics models is defined using constraint theory. An attempt is made to alleviate some problems of qualitative simulation algorithms by drawing upon system dynamics modeling methods and by establishing the structure for the propagation of constraints in these models.
Food self‐sufficiency in Vietnam: A search for a viable solution
Authors: Bach Nguyen Luong , Saeed Khalid 
Published: July 2007

AbstractThis article attempts to assess the effects on an agricultural resource system of policies to maintain food self‐sufficiency in a centrally planned economy. Vietnam's case serves as an illustration. Experimentation with a system dynamics model of the food production system, incorporating relations concerning soil ecology and agricultural land management policy, serves as a basis for this assessment. Short‐run policies to increase production appear to be detrimental to maintaining food self‐sufficiency in the long run. it appears that a sustainable food production policy must incorporate soil conservation and improvement, and population control. Although difficult to implement in a market system, such a policy agenda may be feasible in a centrally planned economy.
A system dynamics model of aircraft carrier survivability
Authors: Coyle R. G. 
Published: July 2007

AbstractThe use of aircraft carriers in offensive operations in waters where an enemy can deploy strong air forces is the subject of much debate, and it is sometimes asserted that the carriers could not survive long enough to discharge a mission. This article analyzes that proposition and shows that a wide range of possible outcomes exists, depending on the carrier commander's actions.By considering the fundamental mechanics of the problem, a number of options for technological improvement are suggested, and it is shown that they have widely differing, and sometimes very unexpected, effects on the outcome.The model requires a blend of discrete and continuous modeling, the main features of which are discussed in the Appendix.
Complex dynamics in low‐dimensional continuous‐time business cycle models: The Šil nikov case
Authors: Lorenz Hans‐Walter 
Published: July 2007

AbstractWhile most examples of complex motion in economic dynamics employ a discrete‐time concept, chaos can also emerge in continuous‐time, nonlinear economic models. It is argued that, (depending on the level of aggregation in the economy) the use of the continuous‐time concept can be mandatory in economic dynamics. The Šil'nikov scenario, based on the existence of homoclinic orbits, is used as a formal means to illustrate the emergence of complex motion in two simple examples from traditional business cycle theory. The consideration of slight nonlinearities in a generalized version of the standard Metzler model with inventories and in Phillips' multiplier‐accelerator model can imply chaotic behavior.
Dynamics of rural development in southern Sudan
Authors: Bontkes Tjark E. Struif 
Published: July 2007

AbstractThis article presents the results of a dynamic simulation study of a rural area in southern Sudan. In order to improve the living conditions of the rural population in this area, three intervention packages were planned: improved veterinary care; improved agricultural practices; and better general facilities like medical care, clean drinking water, schools, and roads. Although these interventions initially seem to benefit the rural population, some worsen the situation after a number of years when compared to the case without interventions, and others are not able to bring about a sustainable development of the area. Especially the improvement of the general infrastructure causes problems in the long run because it accelerates migration from the rural areas to the town. This increases the share of imported sorghum purchased by the town dwellers and diminishes the ability of the rural population to purchase food after a year of a low Productivity. It is concluded that analyzing the dynamics of the system can foster planning of appropriate interventions.
System dynamics as an organizing framework for pre‐college education
Authors: Forrester Jay W. 
Published: July 2007

AbstractPre‐college education is under attack for poorly serving the needs of society. Unless a superior concept for improving education emerges, public displeasure is apt to result in still more of what is already not working. But now, a fundamentally new and more effective approach to education is emerging from advances in system dynamics. System dynamics offers a framework for giving cohesion, meaning, and motivation to public school education at all levels. A second important ingredient, learner‐centered learning, imports to pre‐college education die challenge and excitement of a research laboratory. Together, these two innovations harness the creativity, curiosity, and energy of young people. System dynamics improves on the traditional educational sequence, in which years of learning facts precede use of those facts, by introducing synthesis at an early stage in a student's experience. Such synthesis can be based on facts that even elementary school students have already gleaned from life. Learner centered learning relieves teachers from having to lecture facts to resistant students. Learners take charge of their own learning as they explore, gather information, and create unity out of their educational experiences. A teacher in this new setting acts as a guide and participating learner rather than as an authoritarian source of all wisdom.
Systems, science, and schools
Authors: Mandinach Ellen B. , Cline Hugh F. 
Published: July 2007

AbstractThe Systems Thinking and Curriculum innovation Network (STACIN) Project is a multiyear implementation and research effort intended to examine the impact of a systems thinking approach using mulation modeling software. The purpose of the project is test the potential and effects of using are technology‐based oproach in pre‐college curricula as teach problem‐soliving skills as well as content‐specific knowledge.
System dynamics, determinism, and choice: Toward a reconsideration of the image of “systems man”
Authors: Bowen Michael G. 
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, Universitat Stuttgart, Keplerstr. 17, D‐7000 Stuttgart 1, Germany.
Reality check: A bridge between systems thinking and system dynamics
Authors: Peterson David W. , Eberlein Robert L. 
Published: July 2007

AbstractSystem dynamics models are suppose to be more robust than other kinds of simulation models. However, tests of robustness are usually underused and underdocumented. To allow the extensive use of robustness tests, we have included in the Vensim software a language for defining qualitative and quantitative tests, and a facility for automatically executing the tests on a simulation model. Such automatic tests are called Reality Check tests. These tests provide an explicit indication of model quality and an effective way of comparing models.
Causal policy maps of managers: Formal methods for elicitation and analysis
Authors: Hall Roger I. , Aitchison Peter W. , Kocay William L. 
Published: July 2007

AbstractA connection is traced from the informal policy maps of managers, to some formal methods that have been reported for eliciting causal policy maps from the minds of managers, to commercially available computer‐driven methods for storing, displaying, and analyzing policy maps in a group setting. A gap in available techniques for analyzing policy maps is identified, and a path‐finding algorithm built into an artificial intelligence program is put forward as a step toward closing this gap. It is used to demonstrate a causal‐map analysis as an aid to a group policy meeting.
Simulating the controllability of feebates
Authors: Ford Andrew 
Published: July 2007

AbstractSystem dynamics is used to simulate the impact of feebates to encourage the sale of cleaner vehicles in southern California. With a feebate system, fees would be imposed on dirty vehicles to finance rebates for clean vehicles. The model is used to learn whether the State of California could operate a feebate system in a financially prudent manner. I consider an example in which fees are imposed on conventional vehicles, and rebates are used to encourage the sale of electric vehicles. The simulations show that feebates can be controlled despite the many uncertainties in predicting the future sales of both conventional and electric vehicles.
Loop polarity, loop dominance, and the concept of dominant polarity (1984)
Authors: Richardson George P. 
Published: July 2007

AbstractFounded in the mid‐1950s, the field of system dynamics has intellectual roots reaching much further into the past. This section seeks to publish material from that past that can contribute to current theory and practice. It 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 material, 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.
The dynamics of resource sharing: A metaphorical model
Authors: Morecroft John D. W. , Larsen Erik R. , Lomi Alessandro , Ginsberg Ari 
Published: July 2007

AbstractMost system dynamicists have used the example of a simple shower to explain feedback and to introduce the cyclical dynamic behaviour characteristic of a balancing loop. The damped system's temperature is relatively easy to manage. But with two showers sharing the same limited supply of hot water it is much harder to control the water temperature, because a person “managing” one shower is unaware of the other, yet must react to the aggregate temperature outcome resulting from “joint management” effort. A system dynamics model of a two shower system is presented and is simulated to illustrate the causes and consequences of interdependence in resource allocation, and to explore changes that can improve the coordination of decision‐makers. Insights from the two shower model are then applied to understanding coordination in multinational subsidiaries with overlapping geographical markets. The article ends with some reflections on the value and limits of a metaphorical model.
Non‐participation and system dynamics
Authors: Romme A. Georges L. 
Published: July 2007

AbstractNon‐participation is currently one of the most pertinent problems confronting large organizations. The non‐participation problem is related to two untested assumptions made by the conventional wisdom of participative management: first, power is assumed to flow from top to bottom rather than the other way around and, second, participation schemes provide sufficient opportunities for worker participation. The sociocratic organization provides a participative management model derived from system dynamics concepts which challenges both assumptions. Sociocratic organizations are based on a circle structure, decision making by consent, and double linking between circules. The circular and reflexive nature of these organizations appears to open up real opportunities for participation at all levels.