Principles Of System Dynamics Research Articles

Multi-Project Management in Software Engineering Using Simulation Modelling

Multi-project management is crucial in Software Engineering as it draws the resources from common pools, affects the completion date of other projects, determines the priority of use of resources among various projects, involves the judgment of multi-tasking of a common resource, and eventually, determines the success or failure of the projects. Hence, this paper argues that a formal simulation model using System Dynamics principles should be built to study the dynamics of software multi-project management. However, System Dynamics modelling by itself lacks the capability to construct the multi-project network, and thus confines the use of simulation in a single project environment. Thus, this paper is proposing an integration of the System Dynamics model with a multi-project network constructing method, called Critical Chain Project Management (CCPM). CCPM, not only constructs the network, but also recognizes the interdependencies of the multiple projects. However, the combination of these two principles does not simulate unexpected situations, change of policies and strategies that may be encountered during the project development. Hence, a Scenario model is proposed to be integrated with the System Dynamics and CCPM. With such integration, the project manager can identify the restraining factors in various possible scenarios in the multi-project environment, and provide feasible solutions to the senior management.

MANUFACTURING SYSTEMS MODELLING USING SYSTEM DYNAMICS: FORMING A DEDICATED MODELLING TOOL

Discrete event simulation is a popular aid for manufacturing system design; however in application this technique can sometimes be unnecessarily complex. This paper is concerned with applying an alternative technique to manufacturing system design which may well provide an efficient form of rough-cut analysis. This technique is System Dynamics, and the work described in this paper has set about incorporating the principles of this technique into a computer based modelling tool that is tailored to manufacturing system design. This paper is structured to first explore the principles of System Dynamics and how they differ from Discrete Event Simulation. The opportunity for System Dynamics is then explored, and this leads to defining the capabilities that a suitable tool would need. This specification is then transformed into a computer modelling tool, which is then assessed by applying this tool to model an engine production facility.

Combining multicriteria decision aid and system dynamics for the control of socio-economic processes. An iterative real-time procedure

The 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.

Software-Engineering Process Simulation model (SEPS)

This paper describes the Software-Engineering Process Simulation (SEPS) model developed at JPL. SEPS is a dynamic simulation model of the software project-development process. It uses the feedback principles of system dynamics to simulate the dynamic interactions among various software life-cycle development activities and management decision-making processes. The model is designed to be a planning tool to examine trade-offs of cost, schedule, and functionality, and to test the implications of different managerial policies on a project's outcome. Furthermore, SEPS will enable software managers to gain a better understanding of the dynamics of software project development and perform postmortem assessments.

A simulator of the manufacturing of induction motors

The main purpose of the simulator is to provide feedback in the form of motor cost and production scheduling during the process of motor design. The paper concentrates on modeling and simulating a factory, modeling production costs, and providing examples of how the design of electric motors can be improved by taking manufacturing information into account via software. The simulator uses principles of system dynamics and technical cost modeling to model the flows of materials and the evolution of product through manufacturing stages across the factory floor. The inputs to the simulator are blueprint data for motor design, and the status of the factory. The output from the simulator is cost and schedule information. The simulator also provides a mechanism whereby design variables can be tested for variations that produce cost improvements.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Lessons learned from modeling the dynamics of software development

Software systems development has been plagued by cost overruns, late deliveries, poor reliability, and user dissatisfaction. This article presents a paradigm for the study of software project management that is grounded in the feedback systems principles of system dynamics.

Using computer models in corporate planning

This paper explores the applicability of system dynamics principles in the corporate long range planning exercise of an enterprise. The tools and techniques used for the purpose of corporate planning are grossly inadequate and lamentably unsophisticated to capture the inherent dynamics of the enterprise and its interaction with it's environment. In this paper the different facets of corporate planning have been examined in order to visualize the modelling requirements. An attempt has been made to review and classify the existing corporate planning models. A taxonomy of different types of corporate planning models is provided by classifying these according to parameters, modelling strategy, characteristics and consolidation. Further, the system dynamics methodology is introduced as an appropriate modelling strategy to suit the needs of corporate planners.

A simulation model for corporate planning in a steel plant

A simulation model for corporate planning has been designed for a steel plant based on system dynamics principles. This model has been designed for material flow that takes place through a group of twelve production shops arranged in six stages of production. The model requires a time variant input of demand of seventeen categories of finished steel products and three categories of raw materials. The model generates behaviour of various objectives based on assumptions of the environment. The model is being used by the management for simulating the impact of their strategic policy decisions on corporate objectives. The model also assists the management in designing their long term investment policies related to expansion, modernisation and for smooth flow of production.

Simulating Economic Sanctions and Incentives: Hypothetical Alternatives of United States Policy on South Africa

This paper reports on a part of a pure computer simulation model concerning the inter dependencies and mutual influence of the dyad US — South Africa within the international system. The feedback model is based on several theoretical assumptions and constructed along the principles of Forrester's system dynamics; its initial values and parameters are based on empirical data, the latter calculated by means of statistical procedures. The model attempts to find out how computer simulation can contribute to better knowledge and to the analysis of process behaviour in the international system. The main question is to what extent a change in US policy on South Africa can influence the socio-economic and the political development of South Africa towards liberalizing the government's racial policy. Five experiments were run to answer this question. One models the actual relationship between the US and South Africa, whereas the others deal with strategies of economic sanctions and incentives on the part of the US. The results of the different experiments show hardly any impact on the socio-economic situation, especially on the apartheid policy of South Africa. Economic crises simulated in the model are shifted to the black population. The consequences are reflected more strongly in the relational aspect itself. A US economic boycott strategy spills over into the political field of the dyadic relation, whereas an incentive strategy strengthens cooperation with South Africa and thereby benefits the white power elite.