The aim of the System Dynamics Model KEYNEO is to model the German economy over a long time period (40 years). Keynesian and neoclassical elements form the base of KEYNEO. In the first step a complex feedback structure was developed to model the main economic variables on an aggregate level. The equations for the supply and the demand side of the economy were defined in the second step.
The results of different runs demonstrate that KEYNEO mimics historic data quite good. With the use of optimization tools the parameters could be estimated. The statistical analysis of KEYNEO shows that the results are highly significant. This verification underlines the quality of KEYNEO to model an economy.
In addition, the structure of KEYNEO may serve as input for much more sophisticated models.
The aim of the System Dynamics Model ESCOT is to describe a path towards a sustainable transport system in Germany and to assess its economic impacts. ESCOT was developed within the environmentally sustainable transport (EST) project of the OECD that was designed to set-up the ecological and technical framework of a transition towards sustainable transportation. ESCOT comprises five models: the macroeconomic, the transport, the regional economic, the environmental and the policy model.
The economic assessment for environmentally sustainable scenarios shows that the departure from car- and road freight-oriented transport policy is far away from leading to an economic breakdown. By expanding the time period for the transition we derived even more encouraging economic results.
For the economic assessment it is important that ESCOT considers not only first round effects but also secondary effects. This ability makes ESCOT a powerful instrument for the assessment of such large system changes.
A system dynamics (SD) model without an instructional overlay is not a sufficient learning tool (Spector and Davidsen 1997, Alessi 2000). We propose Cognitive Load Theory (CLT, Sweller 1988) as a theoretical framework for devising effective instructional context for SD models. Providing a systematic distinction between the several sources of cognitive load, CLT specifies what (and why) should be considered when the instructional overlay for a learning environment is designed. Having developed a simple SD model of the theory, we use it to explore how various instructional choices might impact effectiveness of the learning process. Finally, we consider the CLT recommendations in the context of SD-based learning environments and discuss how they may provide input to developing a set of guidelines for design of effective ways to communicate insights of SD models to a broader audience.
CSIRTs are security incident handling organizations serving a parent organization or a constituency of independent organizations. CSIRTs struggle coping with the increasing number and sophistication of incidents; staff is overloaded with work; managers 'over-utilize' their teams. The CSIRT 'mismanagement' problem can be framed as a case of natural resource management. Studies by Moxnes suggest that misperception of dynamics may contribute to natural resources mismanagement. We replicate experiments by Moxnes (2004), reframing the one-stock reindeer rangeland management task as a challenge in sustainable CSIRT management. Our results suggest: 1) The misperception of dynamics persists when the problem context changes; 2) people employ a simplistic anchoring-and-adjustment decision rule to deal with the problem; 3) our data do not support the version of the rule proposed by Moxnes. We hypothesize that the observed misperception might at least in part depend on the way in which the task was presented.
Information Systems are a key factor for firms competitiveness. Thus, their efficient management has become a key concern and security management one of the most relevant issues. An empirical study has been developed to determine the characteristics of security management within Small and Medium sized Enterprises (SMEs). A summary of the main data from this study is presented.
The results of this study have showed that the evolution of security management within firms has evolved through similar patterns of behaviour. Some phases have been defined to explain the evolution of security management within SMEs. The defined phases are: Growth, Integration, Formalization and Involvement. To explain these phases causal loop diagrams and behaviour over time graphs have been used. Both elements help to more accurately understand the mental models of the people in charge of managing the security of information systems.
The implementation of an ERP (Enterprise Resource Planning) demands the development of a complex project. On one hand, the scientific literature presents some key factors which allow the project to reach the expected objectives. However, these researches do not consider the dynamic relationships that take place among these key factors, although interrelations can benefit or stop the project development. On the other hand, there are different useful strategies for an ERP implementation that directly affect the project development. This paper develops a generic model to identify the relationships among the main key factors (best fit with current business process, resistance to change and training). The model has been validated by a company dedicated to ERP implementation in Spain. Finally, the model will also be useful to analyze the impact of the different strategies in the management of an ERP implementation project according with the project cost study.
The quest for the right E-Learning business model is a strategic issue for E-Learning-companies management. But like any new concept, it is not short of confusion and ambiguity. This article gives a short review of the controversial discussion of the value of E-Learning business models and presents a simulation model built on system dynamics concepts to analyse and evaluate formalized E-Learning business models. This simulation model has been initialized and validated by empirical data gathered from literature research and five structured expert interviews. The simulation for different pricing and licensing scenarios for E-Learning products reveals the complex feedback structures in the pricing setting process and their impacts on the performance of a E-Learning content provider.
This paper has two goals: The first is to present a computerized version of Beer Game originally developed as a board game to teach managers the principles of supply chain management. The multiplayer interactive simulation game we develop is 100 percent faithful to the original game, so that experimental results from the physical and computerized environments can be safely compared. The simulation model used to represent the game also illustrates some subtleties that a model builder must be careful about while simulating a discrete and physical game. Secondly, the game was used as an experimental platform and experiments were done in order to analyze game medium (computer vs. board), demand pattern and learning effects on performances of players. One striking result is the fact that subjects who played the board game scored significantly better than those who played the computerized version under the same conditions.
This paper analyzes the design and functionality of the nuclear reactor, and the human failures on on-line operations, which had led to the accident at the Chernobyl power plant, In April 26, 1986. The paper finds that the combination of the Chernobyl-reactor characteristics and freak infringements of safety rules did cause the accident. The former aspect is due to the process of graphite-moderated uranium fission, which tends to increase in reactivity in the case of a malfunction or faulty operation. The latter is caused by the effect that infringements which did not cause accidents in the past lead to more violation of safety rules in the future. Transferred to organizational improvement programs, a corporation has to redesign its structure in the vein that failures cannot spread quickly (i.e. loosely coupled system elements), and to generate an atmosphere in order to encourage and utilize the full benefits of employees participation.
In this paper, we develop a comprehensive eigenvalue analysis for linear models, in order to identify the leverage points in models. The analysis is comprehensive as we develop a closed-form analytic function relating the behavior of any state variable to all parameters in the model. Moreover, by decomposing the behavior into several modes of behavior each characterized by an eigenvalue and an eigenvector it is possible to develop a closed-form analytic function relating a certain mode of behavior to all parameters in the model. In the first section of this paper, we explain the mathematical foundation of eigenvalue analysis. In the second section we identify the origin of the modes of behavior. This enables us to pinpoint the leverage points of the model. Finally, in the last section, for illustration purpose, we apply the method to a linearized version of the classical market growth model. The analysis of this linearized model enables us to explain the model behavior as a superposition of a number of behavior modes, and set the stage for analyzing the original, non-linear version of the model.