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- Type:
- Document
- Fecha de Creacion:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Descripción:
- A new approach to Environmental Impact Assessment (EIA), based on system dynamics concepts is presented in this paper. System dynamics models will however be useful in EIA only if people are able to develop"good" models. The conceptual basis for building an expert system designed to guide people in developing system dynamics models is introduced in this work. Such an expert system will have two main modules: a system dynamics component, which will include basic system dynamics concepts and heuristics; and a specific application component, which will consist of the main relations and rules governing a givenenvironmental area. The system will also include an interface with a dynamic simulation language and with a decision aiding formulation.
-
- Type:
- Document
- Fecha de Creacion:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Descripción:
- The analysis of the evolution of non linear dynamical systems is a complex task. The cases where: i) the model equations can be regarded as a careful and reliable representation of the real system and, therefore, need no revision or modification; ii) the parameter values are precisely known; iii) the initial conditions are precisely known, are rather rare. At least one of the previous conditions is not fulfilled in most of the systems of interest for System Dynamicists. Therefore qualitative analysis of dynamical systems, i.e. the study and classification of their asymptotic behaviours, is of extreme importance, at least in long term models.The methodologies of knowledge representation recently developed in the field of expert systems can be applied to this problem. We therefore developed MAPS, an expert advisor for the qualitative analysis of dynamical systems. MAPS takes the system equations as input, classifies them according to their features and performs the necessary calculations at each stage, sending appropriate messages to the modelist. At present MAPS deals with autonomous second order systems of ordinary differential equations. Further developments are foreseen concerning the study of higher order sytems and the design of an "equations database" for comparison with previously analyzed equations.
-
- Type:
- Document
- Fecha de Creacion:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Descripción:
- The United States Occupational Safety and Health Administration (OSHA) regulates the level of occupational safety and health within firms and inspects firms for violations of its regulations. Regression-based evaluations of occupational health and safety conditions in the United States generally conclude that OSHA's regulation fails to increase either the level of safety or safety-related investment. However, case studies and other forms of qualitative research suggest that regulation does increase both. Resolving this discrepancy requires a research strategy that combines elements of qualitative research and quantitative research. Simulation modelling can be used to bridge these two methods. Generally, the research project constructs a simulation model of accident generation within firms, generates synthetic data from variations of the model, and evaluates the sensitivity of regression methods to variations in the model. This paper presents the structure and base run behavior of the model used in this research project.
-
- Type:
- Document
- Fecha de Creacion:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Descripción:
- A field study carried out during the last seven years on a wintering population of Common Cranes (Grus grus) in Spain allowed us to gather accurate field data on-certain relevant demographic parameters: (a) the size of the Western Palearctic population of this species is estimated to be around 40000 birds, and (b) the age composition in autumn is estimated for 1979-85 to be around 13.5% young. These data enabled us to develop and test a population dynamics model which combines the density- and age-dependent effects on productivity and survival rates. The parameters of the productivity and survival functions were varied within biologically reasonable limits. From the series of possible combinations we selected those that fitted our field data on population size and age structure best. Each variable was then varied to study their influence on the model.
-
- Type:
- Document
- Fecha de Creacion:
- 1985
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 8cc5e98280358f60c3a33cc99e75a20e, and 11576afb39e5cd4a779a3912c119ca81
- Descripción:
- This paper tries to develop a simulation model for managing the parking systems for the city of Kaohsiung . The system dynamics methodology is employed to formulate the model. The causal structure is compartmented into five sectors: (1) the urban activity/travel sector, (2) the modal split sector, (3) the parking sector, which comprises parking supply and parking demand subsystems for both curb and off-street parkings, (4) the traffic/parking interaction sector, and (5) the financial management sector, which attempts to develop causal links between the revenue sources and expenses of the parking system. The model provides the city administrators a policy lab for parking systems management.
-
- Type:
- Document
- Fecha de Creacion:
- 1985
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 8cc5e98280358f60c3a33cc99e75a20e, and 11576afb39e5cd4a779a3912c119ca81
- Descripción:
- This article describes a tool called KBSIM and its use in model preprocessing. KBSIM consists of a knowledge acquisition system and a systems knowledge modeler which translate the responses of human tutors into structural models and facts housed in a system knowledge base. KBSIM accesses and manipulates the knowledge base through an iterrogation engine to produce information on the structure and function of a described system. KBSIM's knowledge base is a hierarchical set of matrix mapped structural models of a system to an expert level of detail. The tool is useful in integrations and strategic management, technology selection and systems modeling and analysis.
-
- Type:
- Document
- Fecha de Creacion:
- 1985
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 8cc5e98280358f60c3a33cc99e75a20e, and 11576afb39e5cd4a779a3912c119ca81
- Descripción:
- Northwest will be a strategically key region for the economic: development of China in the early next century. The Macro-soeioeconomic Model-·SD for a northwestern province (abbreviated to MASEM-SD) has been built. The main purpose of the model is to research into the internal and external conditions and the proper policies which are necessary to realize the great goal in 2000 set by the People's Government of the province. The model further exhibits prospects for the province in the next century and put forth some potential problems that should be paid attention to.
-
- Type:
- Document
- Fecha de Creacion:
- 1985
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 8cc5e98280358f60c3a33cc99e75a20e, and 11576afb39e5cd4a779a3912c119ca81
- Descripción:
- This paper is based on the premise that there is a need to formalise the procedures used in system dynamics. outside the area of computer simulation analysis, to create a stepwise procedure for systemic analysis. This need arises within the subject when applications encroach on areas where quantification is difficult or unacceptable or when a full qualified analysis is not an economic proposition or limited by time factors. The paper suggests that qualitative system dynamics should be propogated through the medium of a general framework for system enquiry. The need for general systemic methodologies is examined and the major elements of system dynamics are used to formulate the basis of such a methodology. This formulation presents a means for qualitative problem analysis in terms of the organisational structure and process control structure of systems using generally proven results developed from quantitative system dynamics models.
-
- Type:
- Document
- Fecha de Creacion:
- 1985
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 8cc5e98280358f60c3a33cc99e75a20e, and 11576afb39e5cd4a779a3912c119ca81
- Descripción:
- The purpose of this paper is to describe a proposed framework for policy analysis and design in complex systems based on the transfer to such systems of control modules developed for simplier and more easily quantified systems. The framework is demonstrated by outlining the development of a dynamic allocation algorithm within a system dynamics model of an engineering system and describing its application in a much larger scale amanagement system. A generalised form of the algorithm is presented based on this experience which serves to highlight its isomorphic qualities. It is suggested that this framework provides an integrated approach to structural policy analysis in complex systems which can also be used to generate significant insights and perspectives into both the physical and control structure systems.
-
- Type:
- Document
- Fecha de Creacion:
- 1985
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 8cc5e98280358f60c3a33cc99e75a20e, and 11576afb39e5cd4a779a3912c119ca81
- Descripción:
- The control policies of a dynamic system are manifest in the rates of change of state variables or levels. Irregular variation in a control will introduce random delay of the flow into the related level. Of particular interest are exogenous rapid disturbances to the rate constants of feedback loops. These disturbances lead to small random delays which build up as the system develops in time. A statistical description of this process can be obtained for a simple feedback loop as a function of the spectrum of the time series of exogenous disturbances. An understanding of this behaviour is useful for modelling stochastic systems.