The strategy to recover components from discarded electrical and electronic equipment to obtain spare parts is promising, especially during the final service phase. In that phase, the original product is no longer produced and the sources of new parts are often limited. Controlling those closed-loop supply chains is challenging. Decision makers have to choose when to acquire discarded equipment, when to recover used parts, and when to produce new parts. We developed a generic system dynamics model that provides a test for various proposed policies to control closed-loop supply chains with parts recovery and spare-parts supply.
In banks decisions are made in a speedy and complex environment often with huge uncertainty. This risk must be managed proactively on an enterprise level. To accomplish this task, a systemic view of the bank is essential. Up to now there is no standardised approach for analysing the overall risk dynamics of a bank that is capable of describing the forces inherent in risk management. Most risk models are constrained by their static view, so that they hardly capture the rapid and discontinuous changes. This paper examines the dynamics by applying system dynamics to enterprisk risk management, with the aim of understanding the banks risk dynamics. In order to simulate the risk dynamics of a universal bank a dynamical enterprise risk model was developed. By combining the disciplines of enterprise risk management and system dynamics, this paper shows how a systemic view can improve structures in bank risk management and the need for large system thinking.
This paper proposes a contribution to the domain of systems thinking skills. Empirical studies have repeatedly shown surprising misperceptions and inabilities in subjects confronted with tasks involving very simple stock and flow systems. Here it is proposed to represent these skills as implicit integration, by which Polanyi modeled our ability to know. In this framework, Dreyfus and Dreyfus five stage model of learning is used to construct three hypotheses concerning the learning of systems thinking and its importance for learning from modeling and interaction with models. The tests elaborated by Ossimitz are adapted for this purpose and some tasks are added, to serve in the experimental corroboration of the hypotheses. Since the empirical work is currently under way, only few results can be presented; consequently the main contribution is the conceptual construction of the hypotheses.
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.