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- Type:
- Document
- Date Created:
- 2008 July 20-2008 July 24
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, ce498623f0349395d0a141a0525190a0, and 6cbae5a21467df4434abbc87da443217
- Description:
- Presently in Iran, gas-driven power stations and combined-cycle power stations compete as they share a common budget allocated by the government for their establishment. With the government offering gas at subsidized rates, the cost price of electricity production at gas-driven power stations is comparatively lower, thereby enhancing their attractiveness for the investor. Therefore, despite their decreased efficiency, the establishment of such power stations is on the increase which in turn imposes additional costs for the government. On the other hand, it would be in the best interest of the government to help increase investment in combined cycle power stations which are far superior in terms of efficiency, and which, in the long run, would be profitable. In this paper we present a model and suggest policies for the government through which a decrease in energy intensity can be achieved without incurring additional costs for the government. We suggest practical ways to optimize existing methods of power production by diverting subsidies offered by the government.
-
- Type:
- Document
- Date Created:
- 2008 July 20-2008 July 24
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, ce498623f0349395d0a141a0525190a0, and 6cbae5a21467df4434abbc87da443217
- Description:
- Planning and managing large-scale projects is non-trivial, as evidenced by the large number of projects that exceed budget and schedule targets. In many cases, rework is a key factor in project delays. Accurate rework prediction is challenging even when the tasks responsible for rework can be identified, the likely project impact is difficult to determine. The work described in this paper examines how Dependency Structure Matrix (DSM) techniques can be leveraged to support and improve System Dynamics applications. It demonstrates how the DSM can be used to identify tasks that are likely to drive rework within a project and exploits System Dynamics to quantify the associated financial and schedule downsides. Using the context of current oil and gas projects, the challenges of managing dependencies between multidiscipline teams working to identify, evaluate, and select a development concept are examined. An overview of DSM fundamentals and approaches used to help with the management of these dependencies is presented. Next a discussion of how System Dynamics can both benefit from DSM analysis and resolve known limitations are considered. The natural integration of DSM and System Dynamics for management of project dependencies is summarized and used as a basis for suggesting new research agendas.
-
- Type:
- Document
- Date Created:
- 2008 July 20-2008 July 24
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, ce498623f0349395d0a141a0525190a0, and 6cbae5a21467df4434abbc87da443217
- Description:
- This paper develops a model of economic growth when emissions are generated as a byproduct of the production process. The production of goods yields income that can be used either for consumption or investment. The production of goods also induces an undesired byproduct emissions. The emissions accumulate to a stock of pollutants which in turn impairs the economy. The consumption of good, in contrast, leads to an improvement of societal well-being. The positive impact of consumption utility and the negative impact of pollution are measured by a welfare function. In this setup of the problem there are two basic intertemporal control problems to solve: First, the society has to decide how much to consume today and how much tomorrow. Second, it has to decide how much of GDP should be invested in pollution abatement over time. The SD model developed in this paper allows simulating the consequences of policy choices and searching for optimal policy strategies. Several simulation scenarios demonstrate the scope of the modeling approach.
-
- Type:
- Document
- Date Created:
- 2008 July 20-2008 July 24
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, ce498623f0349395d0a141a0525190a0, and 6cbae5a21467df4434abbc87da443217
- Description:
- The performance of laymen on tasks testing for knowledge of basic dynamics, such as the bathtub tasks, is consistently weak. There are some reports of beneficial effects of introductory courses in system dynamics or a strong mathematical background. This study investigates the effects of a system dynamics background beyond the introductory level, and strong mathematical background including courses in differential equations and control theory, on the strategies applied to, as well as performance in, the rabbits-and-foxes task. The task objective is to establish equilibrium in a predator-and-prey system. These well-educated participants performed no better than social science students. The strategies applied differed however, and the dynamic systems educated participants did not demonstrate as much misconceptions about the system as social science students have been found to do. The weak performance raises the question if there are better ways to develop a mature concept of equilibrium.
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Jamshidy, Mohamed, "An Analysis of Residential Energy Intensity in Iran, A System Dynamics Approach"
- Type:
- Document
- Date Created:
- 2008 July 20-2008 July 24
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, ce498623f0349395d0a141a0525190a0, and 6cbae5a21467df4434abbc87da443217
- Description:
- Substantial development of counties needs to use the resources in an efficient way. One indicator that shows the degree of efficient use of energy resources is energy intensity. Statistics show that Irans energy intensity was in a bad situation during past years and if this manner of using energy resources continues, it will get worse. In this study a system dynamics approach is used to model changes of energy intensity in residential sector in Iran. By implementation and simulation of this model we found some reasons of this problem in Iran. Then we tried to introduce some policies to make steady improvement in energy intensity in the future.
-
- Type:
- Document
- Date Created:
- 2008 July 20-2008 July 24
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, ce498623f0349395d0a141a0525190a0, and 6cbae5a21467df4434abbc87da443217
- Description:
- Due to increasing market dynamics, Production Planning and Control (PPC) has become more challenging for manufacturing companies. Production plans have to adapt quickly to changing market demands. It is often stated that (1) conventional PPC methods cannot satisfyingly handle unpredictable events, disturbances and market dynamics and that (2) in practice the complexity of centralised architectures tends to grow rapidly with size, resulting in deterioration of fault tolerance, and flexibility. To manage the increasing dynamics inside and outside a production system, autonomous control (AC) of shop floor logistics is a promising approach. The paper gives an overview of the modelling and analysis of AC strategies for production logistics. A universal shop floor model, built with Vensim DSS, is introduced. AC strategies are discussed and implemented. The particularities of modelling a production logistic scenario are presented. Based on the simulation results the logistics performance as well as the influence on the systems behaviour is assessed. The main focus lies on the comparison of the effects of the different autonomous control strategies on the logistics performance of the system and its behaviour. To achieve this goal, sensitivity analysis is used to compare the robustness of the logistic system while interchanging the AC strategies.
-
- Type:
- Document
- Date Created:
- 2008 July 20-2008 July 24
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, ce498623f0349395d0a141a0525190a0, and 6cbae5a21467df4434abbc87da443217
- Description:
- Causal loop diagram largely influences the effectiveness of system dynamics. The complex interpretive nature of management problems makes it difficult to recognize all the existing causal loop relations. In order to build system dynamics models for ill-defined problems, "Group Model-Building" is developed. As discussed by Vennix, one source of these messy situations is different perceptions of individuals. In this paper, we develop an interpretive approach to drawing causal loop diagrams assuming that there are different perceptions about same concepts and the analyst is closely engaged with finding most agreed causal relationships.
-
- Type:
- Document
- Date Created:
- 2008 July 20-2008 July 24
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, ce498623f0349395d0a141a0525190a0, and 6cbae5a21467df4434abbc87da443217
- Description:
- Falls are a serious problem for older adults, often causing severe injuries leading to loss of independence and high cost. Although high effort was already put in research, the situation concerning prediction and prevention is unsatisfactory from practical point of view. A small interdisciplinary team attempt to address the issue in a holistic view using a system dynamics based approach. A simple model was developed based on workshops with experts, which is able to simulate commonly observed circumstances. This leads us to the opinion, that limited success of research up to now is caused by the fact, that modelling approaches used in common are not sufficient for the complexity of the underlying problem. A system dynamics approach would cope much better with this challenge, leading to better predictions and case specific interventions.
-
- Type:
- Document
- Date Created:
- 2008 July 20-2008 July 24
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, ce498623f0349395d0a141a0525190a0, and 6cbae5a21467df4434abbc87da443217
- Description:
- With respect to the career decisions of IT professionals around 2000 a system dynamic model using real data demonstrates how individual market orientation leads on the whole to high unemployment rates in the IT labor market. In the context of the gender equity program of the Civil Service in Germany system dynamic analysis elucidate likewise using real data the significant difference between the institutionally and the individually perceived reality.
-
- Type:
- Document
- Date Created:
- 2008 July 20-2008 July 24
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, ce498623f0349395d0a141a0525190a0, and 6cbae5a21467df4434abbc87da443217
- Description:
- Mental illness is a major social problem. In the United States, the vast majority of mental health services and supports are provided through nonprofit organizations. Recent changes in the field of mental health such as the implementation of evidence-based practices, funding cuts, and statewide policy initiatives such as transformation have increased financial pressures on these nonprofits. Yet few dynamic models exist for understanding the impact of these changes on nonprofit mental health organizations and their performance. This paper seeks to address this gap by presenting a model of financial performance of nonprofit mental health organizations. The purpose of this model is to identify some of the key mechanisms driving nonprofit financial performance. The model is based on the longitudinal financial data of 65 nonprofit organizations providing mental health services or supports in a large metropolitan community, and key informant interviews with executive leaders from a subset organizations participating in a three-year longitudinal study. A simulation model is presented along with implications for state policy makers, managers of nonprofit organizations, funders, and organizational scholars.