Qualitative reasoning about engineering artifacts using qualitative process theory

Over the past few years Qualitative Reasoning about physical systems has emerged strongly as an important area in Artificial Intelligence. Many qualitative reasoning formalisms have been developed and applied to varied domains, namely, hydraulic systems, electrical systems, industrial control etc. This paper examines Qualitative Process Theory [Forbus 84] formalism in view of its abilities and limitations in reasoning about physical systems. The main motivations of this endeavor are - to study the nature of problems involved in reasoning about complex physical systems - to investigate the applicability of Qualitative Process Theory formalism for reasoning about engineering artifacts - to extend the original QP theory to deal with complex physical systems. For this purpose a DC Shunt Generator is modelled using Qualitative Process Theory. The generator is modelled at different levels of complexity. The working Of the various models is discussed and then the the inferences sanctioned by QP theory for that model is examined. The investigation brings out the nature of the tasks involved in reasoning about such complex physical systems and demonstrates the abilities and limitations of the QP theory as a formalism for physical reasoning. Closed loop systems seem to offer tough chaHenge to the investigators in qualitative reasoning. It is in reasoning about closed loop models, that the QP theory fails to reason appropriately. It will be shown how the theory its too abstract quantity space representation and its too-general dependency structure makes the theory a weak one in reasoning about complex physical systems. The quantity space representation of the QP theory is extended and a new dependency propagation scheme is proposed. The generator is modelled on the extended QP theory and the inferences sanctioned by this extended theory are compared with the behavior of the system. The organization of the rest of the paper is as follows: Section 2, covers the modelling of the DC generator using the original QP theory and lists various inference categories involved in reasoning with engineering artifacts. Section 3, deals with the extensions to the QP theory. In section 4, the DC generator is modelled using the extended QP theory and the inferences sanctioned by the extended theory models are compared with the actual behavior of the generator. Some future research avenues and relevant reference materials are included. An algorithm for extracting the qualitative dependencies from quantitative equations is given in the Appendix.1987 best estimate for issue date based on available information

Making intelligent systems team players: Case studies and design issues. Volume 1: Human-computer interaction design

Initial results are reported from a multi-year, interdisciplinary effort to provide guidance and assistance for designers of intelligent systems and their user interfaces. The objective is to achieve more effective human-computer interaction (HCI) for systems with real time fault management capabilities. Intelligent fault management systems within the NASA were evaluated for insight into the design of systems with complex HCI. Preliminary results include: (1) a description of real time fault management in aerospace domains; (2) recommendations and examples for improving intelligent systems design and user interface design; (3) identification of issues requiring further research; and (4) recommendations for a development methodology integrating HCI design into intelligent system design

System Concepts and Formal Modelling Methods for Business Processes

The major quality breakthrough of the 1980s was the realisation by management that business and manufacturing processes are the key to customer service and organisational performance. This thesis is concerned with the overall problem of modelling of business processes. Of special interest is the study of business processes through an interdisciplinary approach that cuts across the boundaries of management and information technology. The overall effort is placed on being able to move from a purely conceptual level of describing a business process to a more formal one, enabling decision making, and driving the analysis away from experience, intuition, and informal debate. The extended review and presentation of the various modelling methodologies given here, serve as a guide to their basic concepts and capabilities. A particular case study - the management of the human resources in a consulting company - has been used in this thesis to enable the evaluation of the modelling techniques. Hence, models have been produced, as well as simulation results to indicate the limitations, the advantages and the information gained. Through this application, the understanding of requirements for modelling analysis and decision making of business processes was acquired. Particularly, two very important techniques were investigated. System Dynamics and Petri nets provide the answers when process models are geared to deliver not only qualitative but also quantitative results. However, Petri nets provide the mathematical notation and the plethora of analysis tools needed for the validation, verification, and performance analysis of the model. Additionally, two different simulation software packages were used, based on these methodologies; Ithink®, which is based on System Dynamics, and Alpha/Sim®, based on Petri nets theory. The model produced in the case study depicts perfectly the capabilities of the two techniques. Petri nets is not the total business modelling solution, it can be complemented by other methods, such as System Dynamics and discrete-time modelling as shown in Chapter 6. The feasibility of all these modelling techniques lies entirely on the analyst, who should use them alternately to satisfy the requirements of the problem