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- Type:
- Document
- Date Created:
- 2009 July 26-2009 July 30
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, b3584c6b53c3f58e0202549d7d851f84, and 4818cb531cdd68d6ec6af3f291216fc7
- Description:
- Real-world concepts can be operationalized into variety of feedback structures which may be mathematically identical but diverse in the number of feedback loops. Factors including model purpose, the modelers perspective and the intended audience all influence the final layout of a feedback rich model. One challenge in the analysis of model behavior is to account for the variations in the appearance of its structure and the feedback loops. This paper focuses on consistency in explaining model behavior illustrates some of the issues related to the cancellation problem and figure-8 loops. Both conditions can potentially lead to poor and even contradictory explanations of model behavior based on its idiosyncratic feedback structure. The paper concludes by illustrating how the pathway participation approach addresses these two issues and calls for comparative studies to using alternative approaches to model analysis to better understand the general principles and subtleties in connecting the structure to the behavior and explaining observed dynamics. Different methods in formal analysis can learn from one another and expedite the development of user-friendly tools to aid model analysis that serve a wider audience.
-
- Type:
- Document
- Date Created:
- 2009 July 26-2009 July 30
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, b3584c6b53c3f58e0202549d7d851f84, and 4818cb531cdd68d6ec6af3f291216fc7
- Description:
- With support from the U.S. Centers for Disease Control and Prevention, we developed the HealthBound policy simulation game for those wanting to experience the possibility of transforming our troubled health system. The game's simulator tracks movement of the U.S. population among states of health, risk behavior, environmental exposures, and socioeconomic status. The model is quantified based on publicly available data from the early 2000s as well as studies from the professional literature on health care utilization and programmatic impact. Players try to steer the country's health system toward greater levels of health, equity, and cost-effectiveness. The goals are difficult to achieve, in part, because the game includes resource constraints, time delays, and side effects of intervention similar to those of the actual health system. The game allows tests of many types of interventions, individually or in combination, and at different points in time over a 25-year time horizon. Various types of output screens allow players to trace the precise reasons for their successes or failures. Those who aspire to lead change on a national scale, or in their own sphere of influence, may benefit by first testing and refining their ideas in this realistic, but simplified version of the U.S. health system, and learning its core lessons.
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- Type:
- Document
- Date Created:
- 2009 July 26-2009 July 30
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, b3584c6b53c3f58e0202549d7d851f84, and 4818cb531cdd68d6ec6af3f291216fc7
- Description:
- Air strategy planners have the difficult task of providing commanders with campaign plans prior to commencing operations, and recommending options during the campaign. BAE Systems has developed the Commanderâs Model Integration and Simulation Toolkit (CMIST), a tool for creating and using simulation models appropriate for high-level strategic decision-making. CMIST provides a unified graphical interface for a variety of methodologies appropriate for systems modeling, including System Dynamics, Bayesian cause-effect, individual agents, Coloured Petri Nets, and other families. Recent development on CMIST enables an agent to run an embedded simulation model representing its own internal, usually simplified, model of the outside world. This proactive intent model allows the agent to project the future state of the world in order to make decisions and take appropriate preventative measures before those future states occur. We discuss comparative results using reactive vs. proactive intent models in the context of our notional Insurgent Growth model.
-
- Type:
- Document
- Date Created:
- 2009 July 26-2009 July 30
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, b3584c6b53c3f58e0202549d7d851f84, and 4818cb531cdd68d6ec6af3f291216fc7
- Description:
- Determining in advance emergency supplies and personnel required for a disaster relief operation is crucial for mitigating the societal impacts of such events. Prompt and effective response to either natural or man-made emergencies requires the analysis of key information where the role of disaster relief organizations is multiple. DROs approve the assistance requested by victims and coordinate supplies and personnel collected and transported to the disaster site. They provide mental health services and shelter while more long-term government aid is decided. The dynamic framework presented here was formulated to understand the complex multi-factor dynamic processes evolving over time during a hurricane emergency. It maps the process of interdependence between resource availability and satisfaction with human services and the influence of the media reacting to victims' complaints. It hypothesizes key mechanisms governing these relationships. Exogenous factors such as customer reactions to the category event; training level of response personnel; race, social stratum, home/pet ownership and education are all taken into account. The model was built with the analysis of data collected from victims of the 2005 Katrina Hurricane and paired with real operational data provided by the American Red Cross and then calibrated/validated by real data from the 2005 Rita Hurricane.
-
- Type:
- Document
- Date Created:
- 2009 July 26-2009 July 30
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, b3584c6b53c3f58e0202549d7d851f84, and 4818cb531cdd68d6ec6af3f291216fc7
- Description:
- Many field studies are available that describe successful applications of model-driven group decision support methodologies. However, these studies might suffer from a potential bias of contextual factors. Recently, there has been a call for a more rigorous testing of the effectiveness of model-driven methodologies. The purpose of our research is to determine the effectiveness of a particular model-driven approach, Group Model Building (GMB), on decision-making in a controlled research situation. In this paper, we first clarify 'effectiveness' as a construct. Then, we describe the present study. We compared groups supported by GMB (13 groups) and not being supported (13 groups) on perceptions of the quality of decision-making and on the quality of their decisions. Preliminary results show that there are no winners. However, some differences in the perceptions of the members of decision-making groups call for further testing in the future.
-
- Type:
- Document
- Date Created:
- 2009 July 26-2009 July 30
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, b3584c6b53c3f58e0202549d7d851f84, and 4818cb531cdd68d6ec6af3f291216fc7
- Description:
- This paper presents the attempt to set up the dynamic land-use transport interaction (LUTI) model MARS (Metropolitan Activity Relocation Simulator) for a nation wide case study of Austria. To this end we adapted the existing urban MARS model. The purpose of the model is to capture the most important interactions and feedback mechanisms between the land-use- and the transport system. Particular attention was paid to the structural changes of the model and the estimation of the transport model parameters as well as the land-use model parameters, which are modelled with a gravity model approach. For this purpose we used the build-in optimizer of the modelling software Vensim by minimizing the sum of squared deviations between observed and predicted data. We present the model fit, estimated parameters and results of a first model run (30 years)
-
- Type:
- Document
- Date Created:
- 2009 July 26-2009 July 30
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, b3584c6b53c3f58e0202549d7d851f84, and 4818cb531cdd68d6ec6af3f291216fc7
- Description:
- The technological developments of our time provide the basis for a continuous flow of new applications and services. But even when allowing for significant improvements in everyday life, some of these innovations need an incredibly long time to be broadly â if at all â accepted in the market. Marketing and technical implementation are often only partially responsible. Consumers additionally need to overcome personal barriers to adopt an innovation. The height of this barrier is determined by manifold aspects like: Financials, required infrastructure, technical affinity, expected learning efforts, and safety concerns. In this article we introduce a market diffusion model that explicitly takes individual adoption barriers into account, while maintaining the top down approach of Business Dynamics. The model includes a feedback loop between the number of existing adopters and the number of consumers prepared to adopt the innovation. It explicitly allows for the adoption by only a portion of the potential customers. Furthermore, the model can reproduce tipping points and visually explain slow market developments or unexpected late successes.
-
- Type:
- Document
- Date Created:
- 2009 July 26-2009 July 30
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, b3584c6b53c3f58e0202549d7d851f84, and 4818cb531cdd68d6ec6af3f291216fc7
- Description:
- In this paper by means of a simple system dynamics model, we have addressed a cycle-producing mechanism in the owner-occupied real estate market which has not been discussed in the real estate economics literature before. This mechanism is based on accumulation of supply and demand which arises from specific stock-flow structure of a durable goods market like the owner-occupied market. Comparison between our model and a famous model of rental market (Wheaton, 1999) shows that despite the rental market, in the owner-occupied market an increase in durability of buildings leads to more intensive oscillations. Also the effect of price elasticity of supply on the cycles in the owner-occupied market is much more complex than that of the rental market. Furthermore a model integrating the two markets is developed. Model analysis reveals that the interrelations between the two markets make the effect of some parameters on the rental market cycles different from what is suggested by the rental market model. Our work uncovers the rich dynamic complexity of the real estate system and can serve as a good example of applying systems thinking principles to complex real world problems. Keywords: Real Estate Cycles; Owner Occupied Market; Durable Goods; Cycle-Producing Mechanism (CPM); Dynamic Complexity; System Dynamics Modeling.
-
- Type:
- Document
- Date Created:
- 2009 July 26-2009 July 30
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, b3584c6b53c3f58e0202549d7d851f84, and 4818cb531cdd68d6ec6af3f291216fc7
- Description:
- In this paper, we describe a model of two judges acting in parallel. We expand work related to the identification of threats by analyzing the effectiveness of including a second judge in the process and identifying its effects on performance and error rates. In addition, we explore the implications for learning under uncertainty.
-
- Type:
- Document
- Date Created:
- 2009 July 26-2009 July 30
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, b3584c6b53c3f58e0202549d7d851f84, and 4818cb531cdd68d6ec6af3f291216fc7
- Description:
- Despite the increasing frequency of cross-border mergers and acquisitions, it is accepted that the rate of success in the post-merger phase remains poor; the main reason for this is widely accepted to be the unsuccessful cultural integration of the two firms involved. Driven by limited time to obtain results, managers from the headquarters (of the acquiring firm) seek to change the culture of the subsidiary (of the acquired firm); the imperatives of a âstrong cultureâ lead them to persevere with the same narrow strategies and objectives. Though organizational culture has been widely studied in the M&A literature, there has been insufficient attention to important dynamic aspects of the process of integration. This paper, with the help of appropriate concepts of culture dynamics from anthropologists, formulates a description of the integration process. Subsequently, by simulating a mathematical model of this process (which explores the impact of two exogenous variables that characterize the context) we bring out the role of endogenous dynamics in determining the success of typical narrow strategies. Specifically, we explain how the nature and strength of the constituent feedback loops shape the non-uniform evolution of relevant constructs in the integration process. We conclude with implications for managers and researchers.