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 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.
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.
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.
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.
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.
This paper demonstrates the use of System Dynamics as a device to simulate a system of infantry and artillery cooperating in joint combat operation.The system under study does not represent a real or actual battle-field. The model represents a scenario describes hypothetical system of accepted theoretical structure of how infantry and artillery may co-operate in order to achieve a desired advance on a real battle-field.The paper will give attention to the planning and controlling of any need to such co-operation, and will give better insights to decision makers before and during such joint operations.We make no claim for revealing analysis of any army strategy, and seek only to show how a System Dynamics model could do if it were constructed by people who fully understood the problems and had access to information at which we can only make guesses.
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.
Rapidly growing cities cause inadequate transformation in the use of land. Government policies tend to be obsolete shortly after implementation, supply of basic services becomes insufficient and expensive, and food prices tend to increase. All these factors are certainly the case in many developing countries where large amounts of population often migrate to settle down, sometimes in dangerous or unhealthy locations, but other times in areas suitable for agricultural purposes in the periphery of the city.The land surrounding the metropolis enters a transitional stage. The territory becomes uneconomical for rural exploitation, but it requires to be supplied with basic services for urban housing. The System Dynamics approach is then appropriate to study and plan these unstable systems.This paper presents a model to assess the growth of peripheral districts of the city. It is a useful aid for policy making in land use issues and a good tool for planning basic services such as health, schooling, transport and recreation.A simulation is carried out for the Periurban District of El Corazon in Medellin, Columbia. A good approximation between historical data and model results can be appreciated. Some scenarios of future growth are explored and the consequence of land-use policies are confronted.
The purpose of this paper is to show some of the schemes used by systems researchers and consultants to collect data about their clients' perceptions of problem situations. These various schemes--which use both words and graphics, consisting more or less of curved lines and arrows-- are useful for 1. helping clients express their perception of a problem situation 2. organizing clients' thinking 3. helping to overcome traditional rivalry between individuals and between groups 4. helping “to create a consensus and commitment to action in a team” (Eden, 1988,2).My paper will discuss three such schemes, proceeding from the 'soft' systems methodology (Checkland, 1981); then 'cognitive mapping' (Eden, 1988); and finally, two system dynamics studies dealing with health care systems.