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-
- Type:
- Document
- Date Created:
- 1983
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, cf82ceba47eedd73f41b00918de16477, and b0aa2a699b54f0d19f6a9d93bdbcfa18
- Description:
- As a step towards increasing our understanding of the dynamics of growth in solar markets, a simlpe generic System Dynamics model describing market penetration by a characteristic renewable energy technology is employed. The analysis demonstrates that for some classes of renewable energy, incentives are now adequate to provide for the necessary rates of growth. Technologies with slightly different features in our model are never able to sustain themselves in the market, no matter what federal subsidies they receive. A third group of solar technologies still needs support, even though it will evolve to become very competitive in the market without any subsidies as little as a decade from now. Relatively modest federal supports of these technologies now can bring them quickly to levels where they are economically, environmentally, and socially attractive energy options that provide significant oil savings. For these technologies federal support through initial stages of commercialization would be appropriate.
-
- Type:
- Document
- Date Created:
- 1983
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, cf82ceba47eedd73f41b00918de16477, and b0aa2a699b54f0d19f6a9d93bdbcfa18
- Description:
- In this paper we outline and evaluate a simple technique for analyzing the ability of a model to reproduce an oscillatory behavior mode. The technique consists of using a model as a predictor, and then performing spectral analysis on the prediction errors. The technique is referred to as the spectral analysis of residuals or SAR test. The paper motivates the use of prediction residuals and illustrates the technique with a simple model of inventory oscillation. The SAR test appears to yield a substantial amount of information about the performance of a model. However, the technique breaks down if the observed behavior is a result of the system being subjected to shocks with similar dynamic characteristics to the system output or if the system has more than one set of mechanisms generating the behavior of interest. The SAR test is not capable of distinguishing between models which can explain the behavior equally well using different state space representations.
-
- Type:
- Document
- Date Created:
- 1983
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, cf82ceba47eedd73f41b00918de16477, and b0aa2a699b54f0d19f6a9d93bdbcfa18
- Description:
- The aircraft survivability model developed is comprised of five submodels: 1) Economy Submodel, 2) Budget Submodel, 3) Procurement Submodel, 4) Attrition Submodel, and 5) Survivability Submodel. The economy submodel generates the annual “Gross National Product” of the United States and “Federal Government Budget”. The budget Submodel uses the military output of the economy Submodel to determine the “Department of Defense Military Budget”. The DOD budget is broken down by service and function (Procurement, Operations and Maintenance, and RDT&E). In the Procurement Submodel, the “Procurement Budget for combat Aircraft” determined in the Budget Submodel is used to generate the parameters: “Acquisition Budget for Combat Aircraft” and “Modification Budget for Combat Aircraft”. The outputs of this submodel are the “Procurement Rate for Combat Aircraft”, and the “Modification Rate for Combat Aircraft”. The Attrition Submodel acts on the inventory of “Combat Aircraft” in the event of war. The number of combat aircraft increased by the outputs of the Procurement Submodel over years of peacetime are reduced in wartime through the “Attrition rate for Combat Aircraft”, which depends on the number of “Combat Aircraft”, the “Sortie Rate for Combat Aircraft”, “Mission Survivability for Combat Aircraft”, and the “Availability of Combat Aircraft”. The Survivability Submodel outputs are the “Mission Survivability for Combat Aircraft” and the “Availability of Combat Aircraft”. The former is the product of the “Susceptibility of Combat Aircraft” and “Vulnerability of Combat Aircraft”, both of which depend on the magnitude of the “Aircraft Survivability RDT&E Budget” outputed from the Budget Submodel. Reductions in the “Susceptibility of Combat Aircraft” and “Vulnerability of Combat Aircraft” affect the “Acquisition Cost of combat Aircraft” and “Modification Cost of Combat Aircraft” used in the Procurement Submodel. Additional feedback lops between the submodels are generated by monitoring the “Relative Strengths of U.S.S.R./U.S. Airpower” and incorporating the effects of this perception on the Economy Submodel, the Budget Submodel, the Procurement Submodel, and the Survivability Submodel. Thus the five submodels interact to form a series of interacting positive and negative feedback loops. The positive loops reinforce themselves leading to increased air power over time. The negative loops act through such constraints as resource availability and spiraling procurement costs to suppress the growth of air power.
-
- Type:
- Document
- Date Created:
- 1983
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, cf82ceba47eedd73f41b00918de16477, and b0aa2a699b54f0d19f6a9d93bdbcfa18
- Description:
- The need for grand unifying principles of the evolution of societal systems is stressed. Examples of such principles from other sciences are given. The economic long-wave or Kondratieff cycle is taken as a reference basis for the study fo the evolution of contemporary technological societies. A number of qualifications to the basic paradigm are made. Several areas of recent structural stability theory are discussed in terms their relevance to societal evolution. Particular stress is placed on the nonequilibrium and bifurcation situations. Structure-function-behavior interrelationships at and near critical points are considered the most important features pertinent to system change or reconfiguration. Attempts are made to provide a fuller integrated theory of societal evolution and structural change. A number of problems relative to system dynamics theory and modeling, and to the use of models in societal management, are introduced and suggestions for improvements are made.
-
- Type:
- Document
- Date Created:
- 1983
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, cf82ceba47eedd73f41b00918de16477, and b0aa2a699b54f0d19f6a9d93bdbcfa18
- Description:
- Recent developments in mathematics show that more-or-less random behavior and spontaneously evolving structures can be given analytical and deterministic representations. Both empirical simulation and theoretical models have been developed in economics that have similar capacities. This suggests that we are entering a new period when structural change and inherently unpredictable events can be explained or understood in terms of endogenous economic forces.
-
- Type:
- Document
- Date Created:
- 1983
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, cf82ceba47eedd73f41b00918de16477, and b0aa2a699b54f0d19f6a9d93bdbcfa18
- Description:
- The Argentine energy authorities elaborated a Plan for the Electricity National Sector, made known in 1979, where the policies to be followed for the period 1979-2000, were established. The Plan proposed basically a dramatic change in the structure of the present generating capacity configuration at the national level, toward a scheme predominantly hydro based. Apparently, the idea of an Electricity Sector less oil dependent, together with the utilization of a huge hydro-potential, which had been neglected until that moment, appeared promising. However, the study of the robustness of such plan, that is, its capability to perform well under different scenarios, became indispensible. The System Dynamics technique provided the possibility of analysing such robustness, by means of a continuous-time simulation model of the Argentine Electricity Sector. This paper presents the results of experimenting with that model, in order to determine the soundness of the policies proposed.
-
- Type:
- Document
- Date Created:
- 1983
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, cf82ceba47eedd73f41b00918de16477, and b0aa2a699b54f0d19f6a9d93bdbcfa18
- Description:
- The present paper carries these converging strands of work forward to address the problem of parameter selection for a given control structure and the comparison of the resultant performance of two competing policy designs.
-
- Type:
- Document
- Date Created:
- 1983
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, cf82ceba47eedd73f41b00918de16477, and b0aa2a699b54f0d19f6a9d93bdbcfa18
- Description:
- Just as the cobbler's children are the last to have their shoes repaired, simulators—individuals who spend careers structuring the world into systematic models—have not developed tools and techniques to systematize and structure their own procedures. As a result, quick and easy communication among all interested parties during modek development is often made extremely difficult. Inputs which might be helpful to the modeller are consequently lost. It is also typically impossible for a client to maintain control over the implementation of his or her model design especially when the client and model builder are physically separated. Finally, when a version of the model is completed, there can be a considerable delay while an entirely new model description, in laymans terms, is prepared. Unfortunately, as a result of time constraints such as a description is sometimes never completed. Based on the work done at Purdue University and the frustration of designing and overseeing the implementation of a system dynamics simulation model at the Department of Energy, this paper describes a structured development and documentation approach to modelling. A systematic approach of this type forces the analyst to think out the implications of a given representation of the world before sitting down at a terminal. It provides a living (continually updated), standardized, written document which not only helps improve the quality of the work but allows for efficient communication between the client and the implementor and eliminates the need for most post model development documentation efforts.
-
- Type:
- Document
- Date Created:
- 1983
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, cf82ceba47eedd73f41b00918de16477, and b0aa2a699b54f0d19f6a9d93bdbcfa18
- Description:
- The research reported in this paper was directed toward understanding and modeling acquisition policy within the DOD. The acquisition model presented was developed at the departmental level and primarily is intended to portray the strategic policy structure of the acquisition system. Lower levels of aggregation were used only where the detail involved was required to capture a major concept. The model parameters and outputs were designated to show what trends would be associated with the implementation of various policy alternatives. Emphasis was placed on the dynamic nature of the relationships within the acquisition system and how they are affected by the policies and external pressures. Exogenous factors input to the model include broad representations of the United States and Soviet economic conditions. The Soviet threat, so key to many of the political battles surrounding weapon acquisition, is generated in the model as a response to threat perceived by them, subject to the economic and political constraints. Incorporation of these and other key relationships was controlled through careful application of a design methodology.
-
- Type:
- Document
- Date Created:
- 1983
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, cf82ceba47eedd73f41b00918de16477, and b0aa2a699b54f0d19f6a9d93bdbcfa18
- Description:
- The U.S. Navy's need for better long-range planning is discussed in light of recent dynamic increases to force plans. The difficulties embedded in the current planning and programming process, and the problems they cause in developing valid approaches are reviewed. The ongoing “Navy Resource Dynamics” project at The George Washington University is then presented as a means of overcoming the difficulties, and providing a timely planning model. The basis of the model is a lagged feedback analysis linking budget “flows” over time to weapon system asset “stocks.” The trade-off between naval force levels and the cost of owning the forces is emphasized with force readiness being a relevant measure.