The Special Interest Group on Model Analysis (SIG-MA) focuses on the development, use and advancement of formal model analysis methods in System Dynamics. These methods currently include: Pathway Participation Metric, Fordâs Behavioural Analysis and Eigenstructure-based methods, amongst others. The focus of this group is not so much on the validity of model equations as, given the equations, how can they best be analyzed and interpreted back to reality. The activities of SIG-MA include facilitating communication amongst model analysts by moderated listserve discussions. These focus on theoretical developments as well as improving the means of communication of analysis results. We are expanding our activities to the further development of tools for model analysis and clear communication of their use (and benefits) in applications. The SIG-MA is open to all system dynamicists interested in formal analysis. Please contact Jill Slinger ( j.h.slinger@tudelft.nl) to join our listserve ( sdsigma@listserv.tudelft.nl).
A simple model allows a rapid comparison of some typical policy scenarios which might be considered under international programs to avoid CO2 emissions caused by forest clearing (Reducing Emissions from Deforestation and Forest Degradation). These REDD policy scenarios can also include consideration of CO2 stored in forest products. The value of avoided emissions can also be determined if expected carbon prices are included. The model focuses on specific simple scenario comparisons. The paper also discusses feedback effects within larger scale setting of CO2 offset availability, CO2 price and emissions reductions.
Graduate degree programs in system dynamics are rare and thus of critical importance to the future of the field of system dynamics. However, to a large extent such programs have not yet been made transparent to the system dynamics community as a whole. The present paper describes the design and rationale for one such program, WPI's M. S. degree program in system dynamics. The goal of the paper is to invite feedback from the SD community about our specific program as well as to facilitate wider discussion about the appropriate content, design, and pedagogy of degree programs and courses in system dynamics.
There is a long-standing debate in the field of social psychology as to which is the primary determinant of behavior, the situation or system in which people act or the personalities of the role players. Psychologists have long studied this problem with controlled experiments on human subjects, and have now come to a general resolution of the debate. However, the field of psychology still lacks an efficient method for teasing apart the relative contributions of personal and situational variables in applied domains. An alternative to human subjects experiments is to employ system dynamics models of role systems, as was demonstrated by Barry Richmond when he attempted to model two classic experiments in social psychology: the Milgram and Stanford Prison experiments. In this paper, we replicate and discuss Barry Richmond's models to present them to a new audience. In addition, we use the models as a springboard to explore the relationship between social psychology and system dynamics and the potential for useful collaboration between the two fields.
This paper focuses on Italy in the context of the Kyoto Protocol. According to the Annex I to the last National Allocation Plan (NAP), Italy's emissions are 95 Mt. CO2 eq. above the Kyoto target of -6.5%, i.e. 19% over the goal. This paper proposes a critical analysis of the Government plan and NAP (National Allocation Plan) based on the analysis of recent Italian energy history and a wide set of policy measures that have been stated in formal documents and not implemented. The study is performed using the ICE (Italy's Carbon Emissions) model. ICE generates energy and carbon emission paths up to 2020 and elaborates sensitivity analysis on caps, carbon prices, and other variables. In particular, the research focuses on the Italian power sector under alternative scenarios of emissions and caps. A conclusion of our analysis is that a significant purchase of carbon credits on the international ET market is necessary. Given the troubled Italian public finance situation, buying carbon credits could represent an unplanned, and maybe not feasible, heavy burden.
Cholesterol metabolism and other factors affecting its dynamics comprise a complex system. The goal of this study is to construct a system dynamics simulation model that can generate long term dynamics of cholesterol metabolism in healthy and hypercholesterolemic subjects, with respect to body weight, diet, and exercise. For both healthy and hypercholesterolemic subjects, the model generates realistic behavior patterns for different types of blood cholesterol and body weight. It is shown in this study that a person can have healthier cholesterol levels by changing her diet and/or doing more exercise. Also itâs observed that exercise is more effective than diet even in cases when the subject does not lose weight. In the case of hypercholesterolemic patients, the model effectively mimics the way typical drugs work and shows how the patient can reach healthier cholesterol levels.
Policy recommendations in public policy venues take on several forms. In some cases, they are well-crafted arguments in favor of a particular course of action. Strong policy recommendations will frame issues in a way that lead decision-makers towards a preferred set of solutions. This paper presents a codebook for developing causal maps from policy recommendation reports and texts. The codebook's strengths and weaknesses are discussed, as applied to a set of recommendations made to reduce flood damages and increase the quality of floodplain management in the U.S. This paper shows how the internal validity of causal maps constructed from qualitative data will be improved by developing codebooks that are reliable, consistent, and transparent.
The present research on the growth of enterprise information technology applications is to build an effective system dynamics model which can reveal the internal laws of the general process experienced by an enterprise integrating the application of modern information technology and management. Based on the literature review and surveys on more than two hundred companies, we sum up the mechanism among the information technology application and key impact factors. In accordance with the conventional modeling methods of system dynamics, a model has been built and tested. The model is also supported by the empirical evidence.