Online Content
Number of results to display per page
Search Results
-
- Type:
- Document
- Date Created:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Description:
- When distribution of economic goods, equipments, ... takes place among different regions, it is expected to carry out in an optimal way, considering "optimal" the way of distribution that assigns more to the neediest regions; thus, numerous factors such as economic conditions, actual equipments, social conditions, population, etc, should be taken into account. The presented model has a double aim: firstly to show the present behaviour of distribution system of investment in Comunidad Autonoma de Murcia, regionally, and secondly to get this distribution to optimize a linear function that represents the regional social welfare as a consequence of the social welfare in each region of the Community and dependent on linear constraints. To reach these objectives, a mixed model that combines both System Dynamics and Linear Programming techniques is constructed; a relation between both procedures is established in order to simulate both the natural behaviour of the distribution system and those decisions that make this distribution to be optimal. Along this report the method carried out to handle mixed models as well as the particular model MURCIA A/I are described.
-
- Type:
- Document
- Date Created:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Description:
- SDSE is a microcomputer based, interactive and integrated system designed to facilitate the teaching and use of System Dynamics in Education. In this way teachers and students without extensive Computer training are able to construct and simulate system models after short period of learning. System Dynamics has been included in Atenea, a Spanish Ministry of Education and Science project in order to introduce computers in Education. Nowadays, SDSE is being used as a supporting program to teach System Dynamics to school and high school teachers in Atenea project courses run by Comunidad Aut6noma in Murcia. In this paper, functional characteristics of the system are described, at the same time that SDSE is applied to build and simulate the simple·and classical example of the inventory control system. Nowadays, SDSE is programmed in FBASIC (FUJITSU FM/7 ) and GWBASIC ( IBM PC and compatible)
-
- Type:
- Document
- Date Created:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Description:
- We propose a functional design for a software system whose aim is to provide support for an structured methodology of modelling and simulation in System Dynamics. The design follows mainly the ideas of Multifacetted Modelling developed by Zeigler. Our approach has been to give a hierarchical version of DYNAMO and a collection of functions for the handling of simulation elements in an unified system.
-
- Type:
- Document
- Date Created:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Description:
- A great interest has been raised recently on chaotic behavior in system dynamics models. This interest is largely justified. The discovery that deterministic systems can show chaotic behavior has deep consequences for the system dynamicist. Among other things, it is well known that strange attractors show a pathological sensitivity to initial conditions. This property impedes the use of a single trayectory (obtained by simulation) as representative of the system behavior. So, the traditional working way of the system dynamicist should be deeply reconsidered if these strange attractors are exhibited by their models. This last is higly possible due to the nonlinear character of these models. Therefore, the system dynamicist should be able to study whether or not those attractors appear in his models. If they appear, then the classical study through the analysis of the trajectory should be rejected, and studies of an stochastic nature -not yet well understood- should be undertaken.
-
Tabucanon, M.T. with K. Saeed and Q. Suhail, "Modeling Fuel Pricing Policy and Consumption Patterns"
- Type:
- Document
- Date Created:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Description:
- This paper examines the domestic energy consumption in Pakistan in the backdrop of the government's pricing policies using a system dynamics model as an explanatory tool. In the context of policy analysis, the simulated behavior of the system are tested based on various pricing schemes of the competing fuels. The simulation experiments reveal, among others, that Pakistan's energy system structure is such that any policy involving government control over the prices will eventually result in an increase in burden on family income of rural and urban poor classes mainly and urban middle class partially. It seems that the only way to redistribute the burden on family income, minimize the burden on national economy, and also achieve conservation of fuels, is by allowing the price of fuels to be determined by the supply-demand conditions of the market.
-
- Type:
- Document
- Date Created:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Description:
- The decision rules in simulation models purport to describe decision-making behavior as it is and not as it should optimally be. Without the criterion of optimality to judge the appropriateness of a decision rule, simulation modelers must rely on empirical confirmation of the structure of their models. In models of small organizations, traditional social science methods may be used. But these methods are infeasible in models of larger systems such as industries or the macroeconomy. This paper shows how direct experiment can be used to confirm or disconfirm the decision rules in simulation models. Direct experiment uses interactive gaming in which human subjects play a role in the system being modeled. The subjects play the game in the same physical and institutional context assumed in the model, and are given the same information set, but are free to make decisions any way they wish. The behavior of the subject can then be directly compared against the behavior produced by the assumed decision rules of the model. An example is described in detail and the correspondence of the experiment to reality is discussed.
-
- Type:
- Document
- Date Created:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Description:
- A three sector system dynamics model (clams, natural predators, and baymen who harvest the clams) was developed to evaluate measures to counter the sharp decline in New York's hard clam (Mercenaria mercenaria) fishery. Six management alternatives were evaluated: effect of shellfish hatchery production on increasing the abundance of clams; growing seed clams on racks to protect them from predators; a maximum size limit on the harvesting of clams; limiting entry of baymen into the fishery; a bounty on predators; and setting aside a portion of the bay as a natural nursery. Model results, which were largely unanticipated, are described.
-
- Type:
- Document
- Date Created:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Description:
- The paper studies with the help of a model the employment decisions of a firm through a business cycle which maximizes its discounted income and assumes that the forecasts are perfectly corred.The firm produces a output function of number of workers employed by the firm at time t. The firm's labor force increases over time as a result of layoffs and quits. The firm can recalls workers at time t only if it has an inventory of previonsly laid off workers. The firm's output is supposed superior or equal to demand (function of price and time) at any time. The solution to the maximization problem will then yield an optimal output and employment plan which the firm proceeds to implement until its expectations about demand at time t.
-
- Type:
- Document
- Date Created:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Description:
- The population of the Tokyo Metropolitan Region increased by about 3 millions in the five years between 1965 and 1970. This increase was due mainly to the flow of populations from the outer field of the Tokyo Metropolitan Region. Until around 1955, population increases were noticeable within the special wards of the metropolis. However, while there has been a recent lull in the increase rate of in-migration, there has been a remarkable increase in the amount of out-migration from the special wards to the four adjoining districts, the Tama district, Chiba Prefecture, Saitama Prefecture, and Kanagawa Prefecture. Out-migration exceeded in-migration in 1967 for the first time since the end of the War and the gap has been increasing year by year. On the other hand there has been gradual rise due to natural increase (the difference between births and deaths) in recent years, which has come to occupy a greater part of the population increase within the area of the Tokyo Metropolitan Region. Our model therefore was formulated to represent such relations between the ward area and the four adjoining districts, as migration, residential effect and commutation. We have divided the whole system into 5 sectors, corresponding to the ward area, the Tama district, Chiba Prefecture, Saitama Prefecture and Kanagawa Prefecture. Each sector is subdivided into population, residence, and enterprise sub-sectors.The simulation was run for the 150 years from 1900 to 2050 and the results contained World War II effect on the population, the number of residences and enterprises of the ward area.
-
- Type:
- Document
- Date Created:
- 1986
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 8be0def879466bb233ec7ae0e7a56898, a6ba3d432669bb4e7e5d1d631a535030, and 23d738ba88f8333bc39725f9cb5bd0b8
- Description:
- The study aims to assess the potential of the forest sector to maintain its leading role in the Finnish economy. The long range future alternatives are simulated by means of a System Dynamics model called MESSU. It is shown that within the limits set by the availability of wood and the low profitability of the forest industry, the growth of total production in the forest industries cannot meet the projected increase in international demand with the present product mix. MESSU covers the whole forest sector (forestry and the forest industry), which makes it possible to study the interaction between the different parts of the sector. The model is built up of seven submodels (modules): forest, forest ownership, roundwood market, harvesting, forest industry, end product market and capital market.MESSU does not only consider economic features of the forest sector, even though they are a central part of the model. Biological (timber growth) and technical (e.g. efficiency of forest industry production and harvesting) features are also included. Further, sosio-economic issues, such as population, urbanization and labor supply dynamics, are considered.