This paper presents a theoretical expansion of the 3-step modelling approach (Costanza & Ruth, 1998), which proposes an incremental progress from scoping models to research and management models. The trade off for increased detail and resolution in model building is a decrease in transparency. This paper aims to provide a context for Mediated Modelling (which happens at the scoping level) and similar system dynamics based participatory modelling approaches, as a missing link toward Adaptive Management. An emphasis is placed on reflective capacity among relevant stakeholders to evaluate the behaviour of systems at various scales and integrated dimensions. A theoretical Multi-Scale Integrated Modelling for Sustainable Adaptive Systems (MIMSAS) framework is discussed as a foundation for three, 6-year research programmes on (1) urban systems, (2) energy systems and (3) watershed and coastal ecosystem services.
There is an increasing concern on the part of corporate sector of the importance to harness knowledge as their most valuable resource. The purpose of this work is to identify the effects of knowledge reuse in service systems. In order to achieve this, a system dynamics model of a software-house's technical support service in Brazil is developed, emphasizing on the use of knowledge bases and its effects over the service system. It concludes that i) the model aids the designer in evaluating several aspects of the system as well as its performance, including the effects of knowledge reuse and ii) based on the simulation results, knowledge management enhances service system performance.
HISTORY OF JAPAN CHAPTER: System Dynamics history in Japan commenced in 1960s; several textbooks of Industrial Dynamics were published in those days. After that, many researchers used system dynamics in their own field individually for about 30 years. Thereafter, system dynamics researchers gathered and founded the Japan Chapter of the System Dynamics Society in 1990. Since then, members were beginning to prepare the International System Dynamics Conference. We held the 1995 conference hosted by Gakushuin University in Tokyo. In 2006, Japan Chapter had over 100 members. As research activities, the Japan Chapter publishes an annual journal and holds regular research meetings and symposiums, usually in Tokyo. The recent theme of the public symposium was "Sustainable Management for the Economic Crisis once in a century". This conference site was in Nagoya University, the first conference outside Tokyo. We always welcome System Dynamics Society members or users who visit Japan. Several system dynamics researchers have already had meetings hosted by the Japan Chapter. Contact with our office is greatly appreciated.
In this paper we use Object-Role Modeling (ORM) to complement System Dynamics (SD). The art of SD modeling lies in discovering and representing feedback processes and other elements that determine the dynamics of the system. However, SD shows a lack of instruments for discovering and expressing precise, language-based concepts in domains. At the same time, the field of conceptual modeling has long since focused on deriving models from natural expressions. We therefore turn to ORM as a prime example to integrate a strong natural language based conceptual modeling approach into the creation of SD models. ORM is a formal fact-oriented approach for modeling information at a conceptual level. In this study we investigate the basic building blocks of these methods using examples. Investigating the foundation of the two methods helps us to better understand their underlying concepts and their differences in update behavior due to state and decision changes. We use SD to capture the dynamic, and ORM to capture the static aspect of a system.
Recent media reports include several large systems engineering failures. These failures are especially alarming given that they span different sectors (i.e., shipbuilding and space systems), and are not isolated to one firm. Therefore we need to ask: Have we lost our systems engineering competitive edge? What can the systems engineering discipline do to correct the apparent discrepancies that appear to be at the root cause of these failures?
The mobile market in Iran is experimenting a transition period from monopoly by the incumbent service provider to a relatively competitive market by introducing the third operator. This paper describes the result of a research concerning the dynamisms of helping the churn in the mobile network by the Number Portability service. The feature adds to the attractiveness of the whole market and potentially stimulates the players to increase their individual attractiveness by either increasing their service quality or reducing prices or both. This dynamism is illustrated by a causal diagram, and a flow diagram has been constructed. The simple proposed model suffices to explore the consequences of different scenarios provided by the policy makers, and helps developing suitable policies to launch this new service. It is shown that improper settings for the service, including the costs, the time to port and the flexibility of porting can cause undamped oscillations in the system.
This paper studies the effect of particular government policies on a cluster formation using a system dynamics modeling approach. A conceptual cluster dynamic model includes the interaction of the cluster with resources, workers, jobs, unemployment, salary, market demand, and production capacity. The considered government policies are raising the cluster's attractiveness, lowering the failure rate of new firms and enlarging the amount of resources. The results show that the cluster will be developed faster and grown larger if the cluster is attractive and/or when the failure rate of new firms is low. Increase in resources also enlarges the cluster but it takes a longer time to develop.
Natural systems and society share a symbiotic relationship with each affecting the health and welfare of the other. More importantly, societyâs impacts on natural systems can lead to negative side effects on society such as increased respiratory illness from air pollution, contaminated drinking water from industrial runoff, and increased skin cancer risk from stratospheric ozone depletion. Mitigating the risks of these side effects often requires the development and implementation of public policy. But policy makers may have a limited understanding of complex natural and societal systems and their interactions. Scientists and engineers can help policy makers by offering their knowledge of these systems as well as technological solutions to mitigate the impacts of societal behavior. However, the expertise of scientists and engineers may not be fully utilized by policy makers for many reasons including scientists and engineers inability to provide the appropriate knowledge, scientists and engineers inability to effectively communicate with policy makers, or policy makers inability to incorporate scientific and engineering knowledge into policy development. The current work develops improved understanding of the interaction of scientists, engineers, and policy makers in the policy process for natural systems. This understanding is developed by constructing, testing, and analyzing a system dynamics model of stratospheric ozone depletion.
Many important risky projects are characterized by stochastic processes embedded in non-linear, feedback structures with delays. System dynamics models may be used to estimate the cash flow resulting from these projects. If these projects include managerial flexibility (real options), a correct financial evaluation of these cash flow requires the use of real options methodology. We adapt prior work on real options valuation in the decision analysis literature to develop a methodology that avoids the need to estimate a risk-adjusted discount rate for the project with options. We illustrate this approach with a model drawn from the wind power industry, which is characterized by numerous uncertainties and high managerial flexibility. We conclude with a discussion comparing this methodology to the previous methods and describe under what conditions each one might be a more appropriate choice.