Group model building is nascent the latest years. However, only few educational institutions offer professional education and research in the field. Furthermore, detailed empirical literature about group model building is rather rare. Hence, this paper will serve three purposes connected to group model building. First, it will document and critically reflect upon a group model session and derive lessons learned. Second, it will create a comprehensive group model building framework based on existing streams of research. The result is a framework that includes context and stakeholder analysis as basic preparation tools for a group model building project. In the more modeling session oriented stages, the approaches of Vennix and Andersen et al. will be integrated. And
thirdly, it will apply the developed framework to a current research project in which the diffusion of energy-efficient innovations will be modeled. Further research will concentrate on validation and elaboration of the developed framework.
Traffic congestion is a significant problem for modern society, but it is a necessary evil. Congestion is the principal mechanism to resolve the surplus demand for road space during peak traffic areas. There is universal agreement that traffic from privately owned vehicles (POVs) will greatly increase in most parts of the world in the next 5-15 years. Acknowledging that traffic congestion will continue to be societys main solution to the competition for scarce road space, this paper proposes additional teleworking facilities with a door-to-door shuttle services with mini-offices. Whether stuck in traffic or not, time spent driving in POVs is unproductive, whereas near office conditions provided in trains, ferries and, nowadays, also in planes make it possible for passengers to stay productive . Teleworking in a door-to-door shuttle service with mini-offices would increase the attractiveness of public transit services in some large cities and, possibly, in larger quasi-urban areas in heavily populated countries. Such condition might provide leverage to deal with heavy traffic, especially traffic congestion. We suggest niches for an experimental transition to door-to-door shuttle services with mini-offices. We propose further systemic studies to find out what kind of industrial synergies would arise and how large societys leverage to deal with heavy traffic could be.
Formal model analysis remains an important and challenging area in system dynamics. This paper proposes a method to incorporate eigenvectors to the now more common eigenvalue analysis of dynamic models. We provide a description of the application of the method to a linear system example.
As a consequence of faster time-to-market and shorter product life cycles, companies today introduce new products more frequently. While new products can potentially bring tremendous value, they also pose enormous challenges as companies are most vulnerable during new product transitions. Due to the high stakes of new product transitions, planning and execution cannot be overemphasized. Nevertheless, our discussions with product transition teams suggested that a recurring handicap during transitions was the lack of a formal process to guide managerial decisions. This work develops a process to facilitate decision making during new product transitions. The proposed process analyzes the risks impacting a transition, identifies a set of factors across departments tracking those risks, monitors the evolution of these factors over time, and develops a playbook mapping scenarios of risks and responses. Our studies show that the transition process helps level expectations across the organization, lessens the chance and impact of unanticipated outcomes, and helps synchronize responses among different departments.
Cancer is a problem that has long been wrought over by philosopher and biologist alike. It provides a tremendous insight into the diversity of complex phenomena, into the ontogeny of order, into the deepest deterministic principles of life itself. Here we try to sketch dynamically the emergence of such a metastatic and invasive process, tying together chemical, molecular, and physiological insights to more clearly define the problem. We follow the progression of small-cell lung cancer in a population of brachial lung cells tracing the molecular, cellular, and systems etiology of this complex disease.
Model analysis in system dynamics (SD) entails articulating exactly how the structure of circular, feedback relations among variables in a system determines its performance through time. This article combines disruptive innovation (DI) theory with SD to show the use and benefits of model analysis with the pathway participation metric (PPM), implemented in the Digest® software. The model replicates the hard-disk makers overshoot and collapse dynamics that DI allegedly caused. Multiple insights emerge from the dynamics the model computes. Model analysis shows that, over five distinct time phases, four different feedback loops become most prominent in generating the hard-disk makers population dynamics from 1973 to 1993. And Digest® helps detect exactly how changes in loop polarity and prominence determine system performance.
We investigate irreversible acceptance dynamics, leading to phenomena typical for paradigm change not described by widely used reversible and static behavioral models, e.g., multistability, hysteresis, critical parameter values (tipping points), irreversible state changes. Based on a recycling model, we explain these phenomena and develop a simple, generic mathematical model describing the basic traits of acceptance dynamics. Analytical investigations and numerical experiments with this generic model show reproduction of the above mentioned phenomena. In addition, the generic model shows the interplay between internal and external forces. The relation of their time constants is shown to play a crucial role, leading to reversible elasticity dynamics or irreversible acceptance dynamics. Critical parameter values (tipping points) separating elasticity dynamics from acceptance dynamics can be deduced from the generic model. We show that some simplifications applied to the waste recycling model lead to the generic acceptance model. Further, the acceptance model is shown to comprise also the well-known Bass model to describe market diffusion of new products. Finally, we discuss benefits of the generic model, its possible extensions to include additional phenomena, and its research implications.
In irrigation systems over-abstraction of water and/or neglected maintenance are common problems
faced by their users. For a generalized system with head- and tail-users, which interact through water
abstraction and maintenance, a feedback structure is presented. It builds on causal relationships derived
from theoretical work on collective action and irrigation. The concept of the model can be looked upon as
a general formulation of two mutually but asymmetrically dependent groups of users with regard to a
common resource. Main objective of the study is to provide a systems framework allowing for a deeper
understanding of the social and institutional nature of irrigation problems. It is embedded in
transdisciplinary research in Kyrgyzstan and Kenya aimed at developing strategies for a sustainable future
in semi-arid rural areas.
Virtual teams are fast becoming the norm in organizations and strategies are needed to deal with the new challenges that they create. Software Project Dynamics is a field of research that uses system dynamics simulation to explore software engineering issues. The objective of this research effort was to enhance systematically the understanding of virtual software engineering by using the system dynamics methodology and existing software project dynamic models. To accomplish the research objective, the following tasks were accomplished: First, an extensive literature review was done. Second, a Software Project Dynamics model was reproduced. Third, the model was used as an experimentation vehicle. This paper suggests that system dynamics is a viable tool in the exploration of virtual software engineering challenges. A new field of research is recommended to deal with additional challenges of virtual software project teams by using system dynamics with the proposed name: Virtual Software Project Dynamics.
Decision makers are often faced with insufficient and incomplete information, yet are forced to make decisions on this basis. The result may often be unintended consequences or situations where too few or too many resources have been allocated to solve the problem. Practicing decision making is often realised through live-exercises, which tend to be extremely expensive, or by using table-top games, providing a much lesser amount of realism to the game. MindLab allows for more sophisticated training arenas to a relatively low cost. The idea is to create a simulation model general enough to accommodate different decision making scenarios, accompanied by relatively rich user interfaces and an experiment setting that gives the game a high level of realism. This paper looks into how the MindLab architecture functions, as well as presenting two different simulation models with accompanied user interfaces that are currently being used with MindLab.