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Markus Schwaninger
Former Member
Title
Prof. em. Dr.
Last Name
Schwaninger
First name
Markus
Email
markus.schwaninger@unisg.ch
Phone
+41 71 224 2382
Now showing
1 - 10 of 17
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PublicationContributions to Model Validation: Hierarchy, Process, and CessationIn the domain of dynamic modeling and simulation, the assurance of model validity is a prominent challenge. An extensive number of contributions concerning model tests, terminology, and the epistemological foundations of validation have been elaborated. These contributions, however, do not fully answer the questions for novice modelers, namely, which validation tests to choose, when and how to apply them, and at what point to cease their formal validation efforts. Our intention here is to help close this gap by introducing a complexity hierarchy of validation tests, an integrative validation process, and a decision heuristic about when to stop formal validation efforts. The paper concludes by providing directions for future research.
Scopus© Citations 61 -
PublicationSystem Dynamics as Model-Based Theory BuildingThis paper introduces model-based theory building as a feature of system dynamics (SD) with large potential. It presents a systemic approach to actualizing that potential, thereby opening up a new perspective on theory building in the social sciences. The question addressed is if and how SD enables the construction of high-quality theories. This contribution is based on field experiment type projects which have been focused on model-based theory building, specifically the construction of a middle-range theory - not a general one. The process of model building and validation is analysed from a theory-building perspective. The resulting theory is evaluated by means of a set of criteria for high-quality theories. As a conclusion, the insighths thus gained are presented and condensed in a tentative set of heuristic principles for model-based theory building.Type: journal articleJournal: Systems Research and Behavioral ScienceVolume: 25Issue: 4
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PublicationSupply System Dynamics : Distributed Control in Supply Chains and NetworksThe purpose of this article is to make a contribution to a more effective management for supply chains and networks, which we are subsuming under the title supply systems. We conceive of supply systems management as the design, control, and development of logistics along the value chain or in value networks. In this article, we concentrate on control, i.e., the regulation and steering of supply systems from production to customer and vice versa, with the help of system dynamics modeling and simulation. Traditionally, supply chain management has been heavily supported by discrete event simulation and optimization models on very detailed levels. Established tools, e.g., Manufacturing Resources Planning, Enterprise Resources Planning, and Production Planning Systems, have emphasized highly specialized functions, such as the planning for optimal capacity use and achievement of delivery goals, via the sequencing, scheduling, and dispatching of individual orders, or the global allocation of resources but without the possibility to evaluate different outcomes of the allocation process. In the quest for efficiency and effectiveness, new approaches to control, which lead beyond these functions of disposition, are needed. We present a model that combines two systemic methodologies that operate on higher levels of aggregation and complement each other: system dynamics to model and simulate the supply chain and cybernetic control to apply control-theoretical concepts, namely proportional, derivative, and integral control, in a combined mode as well as according to a recursive logic of distributed control. This way, substantial improvements in both efficiency and effectiveness can be achieved, and ultimately organizational viability can be enhanced.Type: journal articleJournal: Cybernetics and SystemsVolume: 37Issue: 5
Scopus© Citations 14 -
PublicationModeling a Control System for Organizational ProcessesIt is widely accepted that any well designed organizational process includes a control mechanism through which management decides which aspects of the process performance are to be measured and how these measurements are to be used to change the level of resources utilized in the process. Little is known, however, about the best ways to design such a control mechanism for typical service sector processes. The focus of this research is to study how a variety of control mechanisms performs in managing a business process. The goal is to identify control mechanisms that are effective in different types of environments. This requires modeling both levels, the business process (object level), and the control system (meta level). The fundamental question we ask here is why control systems so often founder. We address the logical aspect of modeling only, not the socio-logical aspects of model use and of implementation. The scenarios for which we try to establish optimal control systems are ones of stationary, dynamic, and turbulent demand patterns. For this purpose we have designed a generic system dynamics model of a business process. The extensive simulation experiments realized with this model corroborate some of the generally acknowledged, basic principles of control, while refuting some of the usually accepted common-sense knowledge about management and organization. The pertinent reflections also lead to some substantive conclusions concerning the design of control systems.Type: journal articleJournal: Cybernetics and systems : an internat. journalVolume: 33Issue: 7
Scopus© Citations 5 -
PublicationTransforming an Agricultural Trade Organization: A System-Dynamics-based InterventionThe management of agricultural trade organizations in Switzerland is characterized by completely new entrepreneurial challenges due to a progressive opening of agricultural markets and a corresponding reform in the state's agricultural policy. The need for well-suited strategic management tools has suddenly become manifest. Given this background, the intervention described in this article took place in a division of a union of cooperatives in the Swiss agribusiness, which is a typical example of a small to medium-sized enterprise (SME). The aim of the project was to search for possible ways to sustain the viability of the division in the future. The intervention started with the development of an overall descriptive network-type model of the strategically relevant issues faced by the division. A system dynamics (SD) model was built as a decision support tool for one of two crucial strategic issues: the organization of the distribution system. Based on the insights derived from model-building and simulation, the management team changed its shared mental model of the issue at hand, achieving a deeper understanding of the situation faced, the options available and their implications. Thereupon, they have started to reorganize the whole distribution system. In sum, the modeling and simulation activities undertaken had a powerful trigger function in the process by inducing organizational learning at a very fast pace.Type: journal articleJournal: System Dynamics ReviewVolume: 18Issue: 3
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PublicationCombining Multicriteria Decision Aid and System Dynamics for the Control of Socio-economic Processes. An Iterative Real-time ProcedureThe paper presents the elements of a new methodology to control complex and hypercomplex socio-economic structures. The control process is iterative, combining the principles of System Dynamics, Control theory and the PROMETHEE Multicriteria Decision Aid (MCDA) methodology. It consists of three main stages: setting up and calibration of a quantitative model, definition of long-term strategies and short-term control. The purpose is to define within a panel of decision makers appropriate strategies towards long-term goals, and to implement suitable control measures. These should in particular help cope with progressive and catastrophic variations in the behaviour of the system.Type: journal articleJournal: European Journal of Operational ResearchVolume: 109Issue: 2
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PublicationA Validation Methodology for System Dynamics ModelsThis paper joins into the effort of the System Dynamics community for higher model quality. The literature in the field has bred a number of contributions concerning tests for the validation of System Dynamics models and the epistemological foundations of validation. To date, however, little has been said about a validation methodology for simulations, especially for System Dynamics models. By validation methodology, we understand the systematic elicitation, description, and reflection of issues related to the subject ‘validation'. The paper's over-all contribution is a blueprint for a validation methodology. We explicitly address the follow-ing three topics: Complexity engineering through validation tests, integrated validation proc-ess, and finally the ‘cessation decision'. The first defines validation tests according to their capability to absorb model complexity; the second designs a validation process which ad-dresses the domains of validation (structure, behaviour and context validation) and the degree of resolution (micro, meso, macro) integratively and iteratively. And third, ‘cession decision' creates a heuristic method for the saturation of a System Dynamics model and conceptually defines when to cease with validation efforts. The paper concludes by pointing out further directions of research about a validation methodology.
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PublicationTheory-Building with System Dynamics: Principles and PracticesSystem Dynamics is a discipline for the modeling, simulation and control of complex dynamic systems. In this contribution, the methodology of System Dynamics-based modeling is argued to be a powerful and rigorous approach to theory-building. The strength od the pertinent process of theory development lies in its high standards for model validation, and in a combination of abductive reasoning with induction and deduction. The argument of the paper is underpinned by an application of System Dynamics to the elaboration of a theory in the new field of Cultural Dynamics.Type: conference paper
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PublicationSystem Dynamics and Cybernetics: A Necessary Synergy( 2004-07-08)