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The traditional approach to the engineering design of process plant is highly sequential with decisions made early in the design phase having a large knock on effect to downstream design processes. A lack of consideration to downstream concerns will either result in design re-work or compromise. Concurrent engineering has been proposed as a design method for resolving the problems inherent in the sequential design process by bringing the different engineering disciplines together at key decision points in the design process, thereby preventing design problems before they occur. Computational support for concurrent engineering aims to develop tools to help team members in sharing knowledge and keep track of the others' needs, constraints, decisions and assumptions [Cutkosky, et al. 93]. Such systems would enable engineering disciplines from each of the design life-cycle stages to communicate and review design strategy. As a group they would be able to explore design alternatives in search of a good solution [Talukdar, Fenves 89]. Knowledge based systems can support the engineering design process by providing advice that accounts for the global concerns. It is argued that such a system should be distributed, due to the problems in maintaining a single large knowledge base, and computational power required to operate a single system. However, wherever expertise is distributed, conflict exists that has to be resolved. The aims of this research are to identify the needs of a computational support environment to aid concurrent engineering design, and to develop a framework to enable disparate design systems to cooperate and produce designs acceptable from the global viewpoint. The 'needs' were identified from a study of the engineering design process, and a detailed analysis into the design and selection of pumping systems to provide a rich example of the problems faced in a specific design process. Cooperation is achieved through 'Negotiation', which resolves conflicts between the various objectives involved in design and is a central theme of this research. Through the provision of a framework to support negotiation the aim is to provide the basis on which individual design programs can cooperate to produce rational designs from a global perspective, thereby bringing life cycle design advice to the earlier design stages.

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The present experiment was designed to investigate the effects of staging (the sequencing of information) and readers' prior content knowledge on the on-line processing and acquisition of procedural text information. An "expert model" of the procedure was used to manipulate text staging as well as to evaluate readers' processing and comprehension of the procedure. / The experimental design consisted of four experimental groups, with six subjects in each group. Subjects at two levels of prior knowledge, experts and novices, were randomly assigned to read one of two differently staged texts, hierarchical and enactment. Various properties of the frame model were used to predict subjects' performance. The experimental design was a mixed between-within subjects repeated-measures multivariate design. / Statistical analyses of data obtained from subjects' reading times and verbal protocols coded against the expert model provided support for a frame construction model of text processing where readers use a top-down application of grammar rules for selectively processing high level procedural information as it becomes available. Both text staging and prior content knowledge affected readers' comprehension on-line. It appears as though these processes are highly automatic since prior content knowledge had limited significant on-line effects.

This thesis studies planning problems whose solution plans are program-like structures that contain branches and loops. Such problems are a generalization of classical and conditional planning, and usually involve infinitely many cases to be handled by a single plan. This form of planning is useful in a number of applications, but meanwhile challenging to analyze and solve. As a result, it is drawing increasing interest in the AI community. In this thesis, I will give a formal definition of planning with loops in the situation calculus framework, and propose a corresponding plan representation in the form of finite-state automata. It turns out that this definition is more general than a previous formalization that uses restricted programming structures for plans. For the verification of plans with loops, we study a property of planning problems called finite verifiability. Such problems have the property that for any candidate plan, only a finite number of cases need to be checked in order to conclude whether the plan is correct for all the infinitely many cases. I will identify several forms of finitely-verifiable classes of planning problems, including the so-called one-dimensional problems where an unknown and unbounded number of objects need independent processing. I will also show that this property is not universal, in that finite verifiability of less restricted problems would mean a solution to the Halting problem or an unresolved mathematical conjecture. For the generation of plans with loops, I will present a novel nondeterministic algorithm which essentially searches in the space of the AND/OR execution trees of an incremental partial plan on a finite set of example instances of the planning problem. Two different implementations of the algorithm are explored for search efficiency, namely, heuristic search and randomized search with restarts. In both cases, I will show that the resulting planner generates compact plans for a dozen benchmark problems, some of which are not solved by other existing approaches, to the best of our knowledge. Finally, I will present generalizations and applications of the framework proposed in this thesis that enables the analysis and solution of related planning problems recently proposed in the literature, namely, controller synthesis, service composition and planning programs. Notably, the latter two require possiblynon-terminating execution in a dynamic environment to provide services to coming requests. I will show a generic definition and planner whose instantiation accommodates and solves all the three example applications. Interestingly, the instantiations are competitive with, and sometimes even outperform, the original tailored approaches proposed in the literature.