ISSN:0883-7066    

DOI:10.1002/sdr.4260040102

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0883-7066    

DOI:10.1002/sdr.4260040103

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractIncreasing computational power in the last decade has led to a breakthrough in the understanding of nonlinear dynamic systems. Deterministic chaos, a distinct mode of behavior qualitatively different from linear modes, can arise in systems with instabilities constrained by nonlinearities.This article overviews this new field. It is observed that deterministic chaos is associated with the presence of a basic instability, often associated with a negative loop with high‐gain and significant delay, that allows small random fluctuations to be amplified and eventually dominate the behavior of the system.The mathematical tools of qualitative analysis of nonlinear systems are applied to familiar models of urban dynamics. Spatial disaggregation in an urban migration model is shown to yield a route to chaos through period‐doubling. Alternative routes to chaos are discussed. Examples from the natural and social sciences are used to demonstrate the applicability of the tools and the ubiquity of such complex nonlinear dynamic phenom

ISSN:0883-7066    

DOI:10.1002/sdr.4260040104

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThis article deals with the application of qualitative analysis techniques to system dynamics ecological models. Examples include the predator‐prey and the Kaibab plateau models. In the former, we study the appearance of periodic motions. Bifurcation analysis allows us to determine the essential parameter that controls the appearance of the limit cycle through a Hopf bifurcation. We also study the limit case in which the model tends to be of the Lotka‐Volterra type.The Kaibab plateau model shows a collapse related to the limited availability of resources in a finite habitat. When we combine the structure of the predator‐prey and Kaibab models, we obtain a model representing the chain predator‐prey‐food. Such a model can show a huge variety of behavior modes, including chaos, which w

ISSN:0883-7066    

DOI:10.1002/sdr.4260040105

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractEmpirical and theoretical investigations of chaotic phenomena in macroeconomic systems are presented. Basic issues and techniques in testing economic aggregate movements are discussed. Evidence of low‐dimensional strange attractors is found in several empirical monetary aggregates. A continuous‐time deterministic model with delayed feedback is proposed to describe the monetary growth. Phase transition from periodic to chaotic motion occurs in the model. The model offers an explanation of the multiperiodicity and irregularity in business cycles and of the low dimensionality of chaotic monetary attractors. Implications for monetary control policy and a new approach to forecasting business cycles are sugges

ISSN:0883-7066    

DOI:10.1002/sdr.4260040106

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe basis of systems modeling has been the Newtonian paradigm that states that the behavior of a system can be understood and anticipated by identifying its components and the causal links between them. This assumption leads to a set of deterministic differential or difference equations that governs the behavior of the system. However, such description is achieved by classifying elements into categories and supposing that only the most probable events in fact occur. But real systems evolve, that is, they add and subtract mechanisms, components, and interactions over time; the deterministic model does not reflect this. Clearly, evolution must therefore result from what has been removed in the reduction process. If we are to understand evolving systems better, to anticipate structural changes, and to explore the real impacts of decisions, we must study the effects on system dynamics of nonaverage behavior. We can then gain new insights into the nature of evolutionary processes and build better models that include the adaptive responses from within the system.

ISSN:0883-7066    

DOI:10.1002/sdr.4260040107

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

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 reconstruct

ISSN:0883-7066    

DOI:10.1002/sdr.4260040108

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

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 b

ISSN:0883-7066    

DOI:10.1002/sdr.4260040109

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractWe demonstrate that different kinds of dynamic behavior may occur in a general migration system. The deterministic nonlinear coupled mean value equations are introduced. The intergroup and intragroup interactions of the subpopulations determine the dynamics of the system. First, the route to chaotic motion in the case of two subpopulations migrating between three regions is briefly presented. In the special case of three interacting sub‐populations migrating between three regions, we then show in detail that all kinds of attractors (fixed points, limit cycles, and strange attractors) exist. Characteristics of the motion, namely the Fourier spectrum, Lyapunov exponents, and the fractal dimension of the attractors, are analyzed. Finally, we discuss the relevance of the results for real migration system

ISSN:0883-7066    

DOI:10.1002/sdr.4260040110

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractNotes and Insightsis 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, F

ISSN:0883-7066    

DOI:10.1002/sdr.4260040111

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY