Since the dynamic input-output method was put forward by W. Leontief, some results have been obtained to a greater or less degree in various fields of quantitative economy, which have played an important role in the application of the method. Yet, insolving the delay-having dynamic input-output models, whether the matrix converse exists or not has not had sufficient mathematical proofs. Having taken these problems into consideration, our paper attempted to solve the problem of multiyear delay-having dynamic input-output model with the application of the properties of system dynamics in structure and time sequence, the properties of BOXLIN and SUM functions, and has combined these two models, the combination of which is possible in the sense of the economy. The DIOSD (Dynamic Input-Output and System Dynamic Model) not only has the advantage of man-and-machine conversation as well as screen display, but also we can put the DIOSD completely into the SD model with the consideration of the overall system structure. Therefore, we can make full use of the advantages of the dynamic input-output model in economy planning and forcasting, and also provide an efficient tool for its future application.
The economy in Taiwan grew rapidly in the last decade. This steep increase strongly affects its transportation system: the number of cars in the urban areas increased dramatically. Some studies forecasted that the number of car in Taiwan urban areas in 2000 will be three times of that in 1984. However, those studies did not consider the feedbacks from the traffic and parking conditions to the car ownership. In addition, some of the possible changes in the system environment are also not being considered, such as the increasing life expectancy of the car, the shortening car renewal period and more and more attractive car purchasing loans policies. This study is an attempt to apply system dynamics methodology to analyze the trend with inclusion of feedback and the above mentioned system environment changes. The results show that due to feedbacks from the limited capacity of roadway and parking and the influence from the system environment, the number of cars in urban areas will only be doubled in the year of 2000. Although the data for this research were very limited, by using the system dynamics methodology we are able to have a better picture of the future trend of car ownership in Taiwan.
This paper provided a two-stage invertory system. It Descrips its problem behavior and structure implement. Analyse the policy design: use inventory and backlog to absorb differences between production and demand, change production to match change in demand, change demand to match production abilities, finally, forecasting reslove permanat and temorory change and lag in production's responce to change.
This paper establishes a system dynamics model to analyse a dynamic productive procedure of an enterprise in Shanghai. The model consists of five sectors, order and supply sector, production sector, material sector, advertising sector and financial sector.There are many products which the enterprise expects to produce, and in the model these products are transformed into two standard products according to the kind of products. The paper analyses the impacts of some soft factors, such as worker's quality, bonus, advertising, etc., on the profit, and also the policy of purchasing materials. The model presents the strategy of how to work out plans between two standard products when the input surpasses the productive capacity of the enterprise.The model is run by using real initial input values in 1985 and 1986. The results are very close to real situations of the enterprise. The sensitivity tests shows that the model is insensitive. So it is adquate to consider that the model is reliable and can be used as basis for dicision making by managers.
Some principle conceptions in microeconomics are simulated by System Dynamic (in brief S.D) in this article. The simulating of two fundamental theories in microeconomics concerned with balanced prices and margin analysis leads to some significant conclusions. Most of these conclusions are now in heated argument in microeconomic field. Our achievement is provided as a test of the proceeding ideas.
There are a large number of references in the literature to the problem of evaluating Information Systems in terms of both efficiency (the technical aspects) and effectiveness (the user's view, and the effect the system has on the organisation). Whereas the efficiency can be defined clearly in mathematical terms, measurement of effectiveness tends to be subjective and is usually measured retrospectively (i.e. some time after installation) using a questionnaire approach, or by expensive simulators, prior to installation.This presentation deals with the initial thinking behind the development of a quick and less costly system dynamics approach to measuring effectiveness, by using a simple model to examine the effect the proposed system will have on the organisation into which it is to be installed.
The most fundamental health studies issue is the discrepancy between expected and actual performances of the Health Care System: the deployment of curative biomedicine is expected to decrease morbidity and costs, but we see everywhere a rise in both. Technological lag, environmental damage, administrative slippage, professional pressures, and new wealth consumption are conventional but, at best, partial explanations. It appears that the rationale is flawed by the use of an inappropriate image of the system out of which morbidity phenomena emerge. The Socio-Ecological Model proposed here links HCS operations with a more appropriate morbidity construct. The individual's subsystems interact with the social-physical environment to create two distinguishable types of morbidity: anatomico-physiological conditions constituting the 'lesions' of the disease process, and interacting experiential, behavioural, and role changes of the illness state. The HCS becomes a significant part of the sick person's environment, and affects the four resulting sub-populations differentially. Care and prevention goals are to move sick individuals/populations toward illness-free and disease-free quadrants and to prevent/slow movement away from them. The counter-intuitive HSC production of morbidity (through, e.g., coronary care, increased life expectancy, pursuit of fitness, early diagnosis, and psychosocial counselling) is no longer surprising. The model suggests a revision of health planning goals, with major shifts in resource allocation.
This study describes policy making and its implementation in water resources to facilitate proactive policy making. A system Dynamics model is constructed, evaluated, and revised with extensive inputs of the actual actors/interested parties in the policy arena.
Model development for policy purposes often involves consulting one or more experts to acquire knowledge about the system that cannot be found in the literature. This poses a knowledge acquisition problem: how to derive the necessary knowledge from the expert(s). This is particularly acute if the number of potential experts to be consulted is large, as might be the case in public policy making. In this paper we will discuss a structured approach to consult a great number of potential experts. The approach was developed for the construction of a simulation model of a regional health care system. The adopted approach, however, is sufficiently general to be employed in other model development processes as well.