This paper examines the effectiveness of different delivery methods for teaching System Dynamics to undergraduate engineering students. The paper presents the findings from a survey of the learning styles of the student population and compares that to the current breakdown of the course content by learning style. It presents the findings of several classroom assessment techniques that were conducted over the course of a semester to evaluate the effectiveness of the delivery methods utilized in the course. The classroom assessment techniques focused on an evaluation of the effectiveness of readings, lectures, labs, and case studies in teaching the material. Additionally, students participated in two self-confidence surveys mid-semester and at the end of the semester, which evaluated their confidence in their ability to accomplish the course objectives and the content delivery methods. Based on this evaluation, the paper presents recommendations for improving the content delivery methods of the course to take advantage of the student populations learning styles.
Ongoing counterinsurgency operations in Iraq present a complex, dynamic environment in which traditional analytical methods struggle to explain the behavior over time. System Dynamics is extremely well suited to analyze this environment as the methodology focuses on understanding the structure of the system and the behavior it creates. This paper proposes a system dynamics model of reconstruction projects for essential services to examine one aspect of this operating environment. One of the many challenges that exist in this environment is determining the proper balance between the use of the Commanders Emergency Response Program (CERP) for small scale and major reconstruction projects. This paper attempts to mitigate this challenge by analyzing the structure of the system, modeling the behavior of the system over time, and proposing policy recommendations to improve the system behavior. Although the model is not calibrated to historical data, it produces behavior consistent with behavior described in Army doctrine. The causal relationships provide valuable insights into the dynamic behavior of reconstruction efforts and their impact on essential services. With further calibration of the model, leaders can develop and evaluate policy alternatives for capacity development to mitigate the impact of the insurgency.
Although both India and New Zealand recognise trade between the two countries as important for their respective economies, the current and past trade in information technology between the two nations has been very low. This research seeks to study this problem situation systemically by analysing the complex interactions of factors responsible for this situation. While most of the literature on IT offshore outsourcing is based on client perspectives, this study takes a service provider perspective. A causal loop model is developed to explain the underlying structure related to this problem situation. Finally, strategies to improve the problem situation are discussed using an analysis of the feedback loops captured in the model.
Unconventional gas has raised debates all over the world following its considerable contribution to the natural gas production of some countries such as the US. The Netherlands, which is a prominent gas producer in the Western Europe, also considers unconventional resources as an alternative to conventional production, which is estimated to significantly decline in the next 25 years. However, the development of unconventional gas in the Netherlands is surrounded by several uncertainties. In addition to parameter uncertainties, uncertainties in the boundaries and structures of the models used in the analysis of this future development play an important role. This study aims to investigate the effects of such uncertainties on the production rate of unconventional gas, by combining the Exploratory Modeling and Analysis method with four different SD models. The results show a wide range of production rate possibilities, where the variety is mostly caused by the model uncertainties. This study can be extended with more model alternatives, and the results of this study can be used in further analysis for robust policy making.
Aggregate continuous time formulations used in System Dynamics models result in the implicit mixing of individual constituents of levels. Normally, this is acceptable as the heterogeneous nature of model variables implies that some individuals counted in a levels value will pass others and exit earlier. In models with a focus on chronological aging and age-related characteristics this phenomenon, which we call cohort blending, can result in large distortions. Though these distortions can be reduced by using aging chains, they persist in a significant way even when using one-year grouping in the aging chains. As an alternative, we introduce an approach we call continuous cohorting in which populations are tracked with cohorts sized the same as the computational interval of the model. This approach eliminates the blending problem with minimal notational and moderate computational burden. The resulting models display quantitative, though limited qualitative, differences from their traditional counterparts and are more easily defensible with demographers and others who study population.
There are increasing environmental concerns in México, as in many other countries, regarding the CO2 emissions tendency, due mainly, to the intensive use of fossil fuel based electric generation. Recently, several laws and amendments have been passed in Mexico with the objective of promoting non-fossil generation technologies, aiming to increase their relative participation in the energy portfolio mix. Although several mid and long term objectives in this regard have been established in Mexico, these would be hard to achieve if the investment capabilities should continue to be directed mainly to fossil fuel thermal technologies, like natural gas on combined cycle plants, and proportionally less, to investment in non-fossil technologies. This article presents and evaluates three scenarios based on a System Dynamics Model, to assess the non-fossil generation capacity investment and timing requirements, in order to achieve both ecological and safety strategic objectives, and at the same time satisfying the electric energy Mexican demand expectations.