The Advanced Fuel Cycle Initiative is developing a system dynamics model as part of their broad systems analysis of future nuclear energy in the United States. The model will be used to analyze and compare various proposed technology deployment scenarios. The model will also give a better understanding of the linkages between the various components of the nuclear fuel cycle that includes uranium resources, reactor number and mix, nuclear fuel type and waste management. Each of these components is tightly connected to the nuclear fuel cycle but usually analyzed in isolation of the other parts. This model will attempt to bridge these components into a single model for analysis. This work is part of a multi-national laboratory effort between Argonne National Laboratory, Idaho National Laboratory and United States Department of Energy. This paper summarizes the basics of the system dynamics model and looks at some results from the model.
Past performance may not be a not true indicator of future performance. Everyone has seen this disclaimer at one time or another. Although this may certainly be true, past performance should certainly be considered when planning for the future. Executives are always seeking ways to make decisions that will help their company to perform better. This paper examines a model that was developed to take a companys financial records and transform them into easy to understand trends and long-term predictors. In addition, it allows the user to adjust system parameters to see the long-term effects to performance.
This study applies system dynamics to explore the long-term influences of multiple policies on handling the financial imbalance of the National Health Insurance (NHI). In order to improve the financial imbalance of the NHI, three policies and three scenarios are proposed. Each policy is evaluated for each scenario. According to the simulation results, the policy of a 20% increase in premium rate, plus a 2% decrease each year in annual rate of change of benefit payments per beneficiary can improve the financial imbalance. However, the benefit payments will be greater than premium revenues from 2008. So, the financial imbalance of the NHI will present again.
The National Health Insurance (NHI) program has implemented in Taiwan since March 1995. The initial balance of revenues and expenditures was stable, but there has been a deficit since 1998. As the deficit problem was mostly caused by the payment system of fee-for-service, the Bureau of NHI (BNHI) implemented global budget (GB) payment system. Under GB, the benefit payments were under control as planned. Since the benefit payments from BNHI are the most part of revenues of hospitals, some hospitals have financial imbalance.
This study uses system dynamics to explore the strategies of hospitals facing GB and evaluate its effects on hospitals and patients. This research is still ongoing and will reach two achievements. First, submitting the stock-flow diagrams can provide the managers of hospitals to have a further understanding on their strategies. Second, building the model can simulate and evaluate the effects of multiple strategies on hospitals and patients.
A new solid waste collection model, called MST, has been developed. It is a result of combining System Thinking and Aggregation Theory and it takes into account real world constraints such as collection frequency, labor shifts and both preventive and corrective maintenance.
MST is a paradigm shift in solid waste collection systems design and operation. It makes possible a more efficient utilization of resources (vehicles and labor) and it is robust against variability sources. MST is the result of having challenged and invalidated a deeply rooted assumption in all models developed up to date.
Simulation and Design Of Experiments were used to compare MST against existing models. Experimental results show significant reduction in the number of trips (Up to 33%), crews (Up to 49%) and vehicles (Up to 40%), which means dramatic operation cost and investment improvements.
Given that systems thinking is a useful methodology in organization learning, the main purpose of this study was to identify and evaluate how and in what ways we could use systems thinking on curriculum/instruction planning in schools. In this study, we used ethnographic methods of observation and in-depth interviewing to gather information. The study took place in six public elementary schools. The evaluation was focused on the following questions: (a) What happened when the model were used?, (b) What did participants think about using the model in planning and instruction? and (d) In what ways did the use of the model influenced professional development? Evaluation data was collected from three primary sources: (a) principals and administrators interview (b) teachers curriculum, lesson plans, interview, and responses to an attitude survey; and (c) researchers observational notes. Conclusions made based on the results of this study. First, systems thinking can increase the quality of administrator-teacher and teacher-teacher interaction, teachers curriculum/instruction planning, continuous assessment of curriculum/instruction, and immediate and formative feedback. Secondly, it can also decrease overall time required on task of curriculum/instruction designing in the long run. Consequently, it promises curriculum/instruction design with more accountable quality.
System dynamics has always held the potential to synthesize and advance theories in social science. Increasingly, social scientists and policy makers are recognizing the importance of complexity and turning to methods like system dynamics, geographic information systems, social network analysis, and agent based modeling. All of these approaches draw on some underlying modeling mathematical framework. This research reports on a method for integrating system dynamics with social network analysis and geographic information systems. The method is then applied to the specific problem of improving city residents perceptions of crime and safety in a model based on existing social theory.
Mental health service systems are inherently complex, both in their detail and dynamics. System dynamics offers great potential to help policy makers, administrators, and researchers make better decisions about service system changes. However, efforts have been constrained by not being able to construct numerical reference modes without making strong assumptions about the structure of the case flows. This paper presents a novel approach to generating numerical reference modes from administrative databases that is based on computation theory. The method is validated with simulated datasets, and its feasibility and substantive significance demonstrated in an analysis of a merged child welfare database containing 10,250 children and adolescents.
Skilled human movement is apparently easily produced and highly coordinated despite the high number of degrees of freedom controlled during its execution. Here, we examine the learning of a whole body movement over practice from three levels of analysis: 1) elemental, 2) subsystem, and 3) macroscopic order parameter, with respect to the role of constraints in motor skill acquisition. With practice, the body segments were re-organized to achieve the 3 sub-tasks, namely: 1) a medio-lateral forcing torque, 2) a vertical downward force and 3) an anterior-posterior equilibrating torque. The output complexities of the two subsystems, the forcing (medio-lateral) and equilibrating (anterior-posterior) motions of the center of mass changed in a compensatory manner, increasing or maintaining the stability of the overt behavior. This pattern of findings supports the ideas of dynamical approaches to motor learning and holds interesting parallels to tenets of the Theory of Constraints (Goldratt, 1990) for system (re)organization.
The members of the Health Policy SIG agreed at the Oxford conference in 2004 to begin a collaborative effort to examine national health care system reform from an SD perspective. The first product of this collaboration is a paper being presented at one of this years parallel sessions, entitled Achieving health care reform in the United States: Toward a whole-system understanding. The paper includes a series of causal loop diagrams laying out an initial theory of why reform efforts have largely failed in the U.S. and outlining the characteristics of more effective reform. This paper was recently distributed to all HPSIG members for their comments, and also to some U.S. health system experts from outside SD. During the special Sunday afternoon session we will review the comments we have received and also hear directly from a few of the outside experts who are able to join us in person. We will also look to non-U.S. HPSIG members for an international perspective, and talk about how we can best expand our collaboration both internally and externally during the year to come.