A System Dynamics Model for Cocaine Prevalence Estimation and Trend Projection

1993 ◽  
Vol 23 (2) ◽  
pp. 251-279 ◽  
Author(s):  
Jack B. Homer
Keyword(s):  
System Dynamics ◽  
Crack Cocaine ◽  
Simulation Models ◽  
Policy Implications ◽  
Dynamics Simulation ◽  
Prevalence Estimation ◽  
National Indicator ◽  
Sensitivity Tests ◽  
Indicator Data ◽  
Alternative Scenarios

In this article the author presents a system dynamics simulation model that reproduces a variety of national indicator data reflecting cocaine use and supply over a fifteen-year period and provides detailed estimates of underlying prevalence. Sensitivity tests are conducted that clarify observed trends such as growth in the compulsive use of crack cocaine and decline in the casual use of cocaine powder. Alternative scenarios with possible policy implications are simulated and projected through the year 2002 and the results are assessed. Researchers and decisionmakers hoping to understand and anticipate the dynamics of illicit drug use may benefit from simulation models that are realistic in detail and broad in scope.

Dealing with Multiple Models in System Dynamics

2014 ◽  
Vol 3 (4) ◽  
pp. 17-35 ◽  
Author(s):  
Willem L. Auping ◽  
Erik Pruyt ◽  
Jan H. Kwakkel
Keyword(s):  
System Dynamics ◽  
Simulation Models ◽  
Dynamics Simulation ◽  
Multiple Models ◽  
Top Down ◽  
Bottom Up ◽  
New Approach ◽  
Behavioural Patterns ◽  
Copper Availability

This paper introduces an approach to compare simulation runs from multiple System Dynamics simulation models. Three dynamic hypotheses regarding the uncertain evolutions of long-term copper availability are introduced and used to illustrate the new approach. They correspond to three different perspectives on the copper system (global top-down, global bottom-up, and regional top-down). Although each of these models allows to generate a wealth of behavioural patterns, the focus in this paper is on the differences in trajectories caused by different models for identical values of shared parameters and identical settings of other assumptions, not on differences in behavioural patterns caused by each of the models. Hence, differences in trajectories between the three models are identified, quantified, and classified based on a quantified measure of difference. For these models, small differences between the trajectories are only found in stable runs, while the alternative perspectives are largely responsible for medium to large differences. Hence, it is concluded that multiple dynamic hypotheses may have to be modelled when dealing with uncertain issues.

scholarly journals A System Dynamics Simulation Applied to Healthcare: A Systematic Review

2020 ◽  
Vol 17 (16) ◽  
pp. 5741 ◽  
Author(s):  
Mohammad Reza Davahli ◽  
Waldemar Karwowski ◽  
Redha Taiar
Keyword(s):  
System Dynamics ◽  
Patient Flow ◽  
Simulation Models ◽  
Dynamics Simulation ◽  
Research Areas ◽  
System Dynamics Simulation ◽  
Systematic Selection ◽  
Dynamics Models ◽  
Developing System

In recent years, there has been significant interest in developing system dynamics simulation models to analyze complex healthcare problems. However, there is a lack of studies seeking to summarize the available papers in healthcare and present evidence on the effectiveness of system dynamics simulation in this area. The present paper draws on a systematic selection of published literature from 2000 to 2019, in order to form a comprehensive view of current applications of system dynamics methodology that address complex healthcare issues. The results indicate that the application of system dynamics has attracted significant attention from healthcare researchers since 2013. To date, articles on system dynamics have focused on a variety of healthcare topics. The most popular research areas among the reviewed papers included the topics of patient flow, obesity, workforce demand, and HIV/AIDS. Finally, the quality of the included papers was assessed based on a proposed ranking system, and ways to improve the system dynamics models’ quality were discussed.

scholarly journals Consolidating findings from business process change case studies using system dynamics: The example of employee morale

2012 ◽  
pp. 455-480
Keyword(s):  
System Dynamics ◽  
Case Studies ◽  
Business Process ◽  
Business Process Management ◽  
Process Management ◽  
Simulation Models ◽  
Dynamics Simulation ◽  
Employee Morale ◽  
Process Change ◽  
Complex Relationships

In this paper, we explore system dynamics as a useful approach to consolidate findings from case studies on business process change (BPC) projects. We compile data from 65 BPC case studies to develop a system dynamics simulation model that helps us to investigate ‘employee morale’ as an important construct in BPC projects. We show that such simulation models consolidate the complex and often non-linear findings from BPC case studies in a way that makes it available to discourse among researchers, lecturers and students as well as BPC professionals. Thus, this paper contributes to knowledge management and learning by suggesting system dynamics as a valuable approach to illustrate and convey the complex relationships between important constructs in BPC. This paper also contributes to the domain of business process management by demonstrating the benefits of system dynamics as a way to review and consolidate the abundance of BPC case studies.

A Model-Based Exploration and Policy Analysis Related to Prostitution and Human Trafficking

2014 ◽  
Vol 3 (4) ◽  
pp. 36-64 ◽  
Author(s):  
András Kővári ◽  
Erik Pruyt
Keyword(s):  
System Dynamics ◽  
Policy Analysis ◽  
Simulation Model ◽  
Human Trafficking ◽  
Simulation Models ◽  
Dynamics Simulation ◽  
Supply Side ◽  
Demand Side ◽  
Deep Uncertainty ◽  
Model Based

This paper presents a model-based exploration and policy analysis related to prostitution and prostitution-related human trafficking. After a brief introduction to prostitution and prostitution-related human trafficking, the paper zooms in on the Dutch situation. A System Dynamics simulation model related to the Dutch situation developed to explore and provide policy insights is subsequently presented. Using the simulation model, policies are first of all tested, and preliminary conclusions are drawn. These preliminary conclusions are further tested under deep uncertainty, using variants of the simulation models. The final conclusions are that supply side measures alone are counter-productive and that demand side measures are necessary but insufficient to solve prostitution-related human trafficking.

scholarly journals Analysis of the performance of the ship steam boiler using simulation

2009 ◽  
Vol 13 (4) ◽  
pp. 11-20
Author(s):  
Josko Dvornik ◽  
Enco Tireli ◽  
Srdjan Dvornik
Keyword(s):  
System Dynamics ◽  
Simulation Models ◽  
Simulation Modelling ◽  
Dynamics Simulation ◽  
Steam Boiler ◽  
Linear Character ◽  
New Information ◽  
Non Linear ◽  
Steam Boilers ◽  
Non Linear System

The aim of this paper is to demonstrate the successful application of system dynamics simulation modelling at investigating performance dynamics of the ship steam boiler. Ship steam boiler is a complex non-linear system which needs to be systematically investigated as a unit consisting of a number of subsystems and elements, which are linked by cause-effect feedback loops, both within the system and with the relevant surrounding. In this paper the authors will present the efficient application of scientific methods for the research of complex dynamic systems called qualitative and quantitative simulation system dynamics methodology, which will allow for production and use of higher number and kinds of simulation models of the observed elements, and finally allow for the continuous computer simulation, which will contribute to acquisition of new information about the non-linear character of performance dynamics of ship steam boilers in the process of designing and education. Ship steam boiler will be presented in POWERSIM simulation language in mental-verbal, structural, and mathematical computer models.

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