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-
- Type:
- Document
- Date Created:
- 1995
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 6214ef14bd960d7be5cd8a816a71dc52, and 12420ec6bd5f758d2b4dea59aabd75a9
- Description:
- The evaluation of investments in flexible assembly system lacks of an appropriate methodology. First a brief review of decision making process regarding complex investments is given. Such decisions have to be made in the tension of hard and soft decision criteria which often produce a dilemma for the decision maker: Considering only short-term effects in terms of hard criteria will usually kill investments proposals. In contrast managers feel the need for the investment but have difficulties to justify their intuitive insights. As a possible solution a System Dynamics based approach is proposed to bridge the gap between rational and intuitive judgment. The approach combines qualitative and quantitative criteria by using a computer-aided step-by-step modelling concept.
-
- Type:
- Document
- Date Created:
- 1995
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 6214ef14bd960d7be5cd8a816a71dc52, and 12420ec6bd5f758d2b4dea59aabd75a9
- Description:
- This paper attempts to build a coherent picture of the way in which various system problem solving methodologies relate to one another. The work builds on the discussion and views expressed at the 1994 System Dynamics Conference that held at Stirling and expressed in the special edition of the System Dynamics Review entitled "System Thinkers, System Thinking". The underlying premises, assumptions and terminology of a number of such approaches are reviewed, contrasted and summarized. It is argued that, in philosophical and academic terms, System Thinking should be considered as a total framework which subsumes all system approaches to understanding human activity. Further, that there exists a range of System Thinking methodologies which can defined and contrasted by positioning them dependent on the degree of vagueness (to be relevant) and their degree of rigour (to be meaningful). It also suggested that their base position may shift dependent on their area of application. It is hoped that this paper or a derivative of it might be used as a reference by practitioners to explain to end-point users if system methods how their own approached fits into a wider and integrated framework.
-
- Type:
- Document
- Date Created:
- 1995
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 6214ef14bd960d7be5cd8a816a71dc52, and 12420ec6bd5f758d2b4dea59aabd75a9
- Description:
- When firms face the possibility of making fundamental change, as opposed to incremental improvements, to maintain their competitiveness, their senior teams face particularly uncertain times. This paper focuses on a system dynamics model that captures that situation of an industry experiencing the switching of its production plans to a new process technology. The model enables the complexity of this situation to be represented, and facilitates a clearer understanding of the expected industry dynamics. The results show that an individual firm facing the up-grade decision must consider the impacts of the change across a number of dimensions, and demonstrates that the point in time along the industry's endemic capacity-building / price cycle may have an important impact on the economics of the decision. The paper is also able to draw some comparisons between this and the other approaches to modelling technology change decision-some comparisons between this and other approaches to modelling technology change decision-making.
-
- Type:
- Document
- Date Created:
- 1995
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 6214ef14bd960d7be5cd8a816a71dc52, and 12420ec6bd5f758d2b4dea59aabd75a9
- Description:
- Resent evidence suggests the connection between quality improvement and financial results may be weak. Consider the case of Analog Devices, Inc., a leading manufacturer of integrated circuits. Analog's TQM program was a dramatic success. Yield doubled, cycle time was cut in half, and product defects fell by a factor of ten. However, financial performance worsened. To explore the apparent paradox we develop a detailed simulation model of Analog, including operations, financial and cost accounting, product development, human resources, the competitive environment, and the financial markets. We used econometric estimation, interviews, observation, and archival data to specify and estimate the model. We find that improvement programs like TQM can present firms with a tradeoff between short and long run effects. In the long run TQM can increase productivity, raise quality, and lower costs. In the short run, these improvements can interact with prevailing accounting systems and organizational routines to create excess capacity, financial stress, and pressures for layoffs that undercut commitment to continuous improvement. We explore policies to promote sustained improvements in financial as well as nonfinancial measures of performance.
-
- Type:
- Document
- Date Created:
- 1995
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 6214ef14bd960d7be5cd8a816a71dc52, and 12420ec6bd5f758d2b4dea59aabd75a9
- Description:
- This paper carefully examines the classical system dynamics practice in the context of human learning process and attempts to explicitly state an implementation procedure that should enhance the use of modeling as a thinking companion at a wide scale. A generic model of learning is used to delineate the principles of conduct of system dynamics modeling. Further, the various activities called for are grouped into a set for four core competencies which are based on four key human abilities. The organizing principles which must be superimposed on the learning abilities to deliver the core competencies are also discussed. A clear statement of the principles of the learning process in system dynamic practice should transform system dynamic modeling from an art learnt mostly through apprenticeship of experts to craft acquired through written word.
-
- Type:
- Document
- Date Created:
- 1995
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 6214ef14bd960d7be5cd8a816a71dc52, and 12420ec6bd5f758d2b4dea59aabd75a9
- Description:
- The field of system dynamics first envisioned by Forrester in 1956 is approaching its fortieth anniversary. It has experienced two significant revolutions: changes in practice wrought by the development of iconographic software and the shift from modeling to improve a process to modeling for the purpose of improving people's mental models (Forrester 1992). Its third revolution---expanding the pool of practicing modelers far beyond the nucleus who have received university training ---has been underway since STELLA hit the schools in the late 1980s. A fourth revolution moving to the forefront qualitative modeling based on word-and-arrow archetypes---began quietly in the mid 1980s (e.g., Wolstenholme and Ciyle 1983) and exploded on the scene with the publication of The Fifth Discipline (Senge 1990). These resent and ongoing revolutions carry promise and potential pitfalls for the field.
-
- Type:
- Document
- Date Created:
- 1995
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 6214ef14bd960d7be5cd8a816a71dc52, and 12420ec6bd5f758d2b4dea59aabd75a9
- Description:
- An elegantly simple and understandable model composed of generic structures is shown to move from damped oscillations to repeated period doubling, leading eventually to chaos. The third order structure contains a balancing loop with a delay and integral control that attenuates as the accumulated pressure gets relatively large. The model and its behavior are so classic and it so quickly converges on its attractor that it may well serve as an ideal structure with which to introduce complex nonlinear behavior and deterministic chaos. Unfortunately, the model contains a subtle error, which, when corrected, destroys in model's ability to exhibit complex behavior. Reflection on these results suggests a number of cautions about modeling practice.
-
- Type:
- Document
- Date Created:
- 1995
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 6214ef14bd960d7be5cd8a816a71dc52, and 12420ec6bd5f758d2b4dea59aabd75a9
- Description:
- The idea of sustainable cities has become central to the concept of sustainable economic development. This paper demonstrates that system dynamics modeling can be effectively used to study the forces preventing the sustainable development of cities. The problems being experienced by cities located in both the less industrialized and industrialized nations are examined, and a slate of current policy prescriptions is described. Simulation runs from a system dynamics model created to examine some of the barriers to the sustainable development of cities are presented and their implications for public policy are discussed.
-
- Type:
- Document
- Date Created:
- 1995
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 6214ef14bd960d7be5cd8a816a71dc52, and 12420ec6bd5f758d2b4dea59aabd75a9
- Description:
- This paper deals with an extension of the "Polis" model that focuses on the subject of Sea Power. The presentation follows two complementary lines: the simulation of the naval conflict arising from Greek colonization westward during the last millennium BC; the discussion of this model within the general approach to Sea Power adopted by the leading authors in the field, Mahan and Kennedy. The conclusions concern the actual limits of the Polis in modeling Sea Power and further steps in its development. Finally, the main difficulties involved in issues of this kind are briefly discussed.
-
- Type:
- Document
- Date Created:
- 1995
- Collection:
- System Dynamic Society Records
- Collecting Area:
- University Archives
- Collection ID:
- ua435
- Parent Record(s):
- 23d738ba88f8333bc39725f9cb5bd0b8, 6214ef14bd960d7be5cd8a816a71dc52, and 12420ec6bd5f758d2b4dea59aabd75a9
- Description:
- As the filed of system dynamics matures, and the number of available tools increases, the problems related to incompatible model formats consume increasingly large portions of researchers, educators, and model users time. Manifestations of these problems are many: Researchers may be unable to communicate models because they are using different tool (or different versions of the same tool). Educators face problems distributing models because schools use different tools. Authors have problems including a model disk with their books, as readers use different tools. Similar problems have been experienced with other tools, like word processors and drawing programs. The kind of solutions that are used for transferring documents between word processors can be applied also to system dynamics models. One solution would be to implement a series of model conversion filters in each SD tool. (This corresponds to the way MS-Word may load and store files in WordStar, Word Perfect, Works, and Write format). Another solution would be to define a common standard file format for interchanging models. (This corresponds to formats like plain text and Rich Text Format for documents, and BMP, EPS, GIF, PCX, TIFF, and WMF for graphics.) The latter approach has several advantages. 1) Each software tool need only support one foreign file format, in addition to its native file format. 2) The software tools need no knowledge of each native file formats. The benefits of developing a model interchange file format are many; 1) Models may be stored in a common format (e.g., in libraries). 2) Models may be transferred in a common format (e-mail, diskettes included in text books, etc.). 3) Co-development of models. 4) Easier use of several tools by the same user.
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