Working Notes from the 1992 AAAI Spring Symposium on Practical Approaches to Scheduling and Planning

The symposium presented issues involved in the development of scheduling systems that can deal with resource and time limitations. To qualify, a system must be implemented and tested to some degree on non-trivial problems (ideally, on real-world problems). However, a system need not be fully deployed to qualify. Systems that schedule actions in terms of metric time constraints typically represent and reason about an external numeric clock or calendar and can be contrasted with those systems that represent time purely symbolically. The following topics are discussed: integrating planning and scheduling; integrating symbolic goals and numerical utilities; managing uncertainty; incremental rescheduling; managing limited computation time; anytime scheduling and planning algorithms, systems; dependency analysis and schedule reuse; management of schedule and plan execution; and incorporation of discrete event techniques

The Integration of Multiple and Diverse Knowledge Representation Paradigms using a Blackboard Architecture

There is increasing evidence that designers of future real-time embedded systems are turning to knowledge-based techniques in order to solve complex problems where algorithmic techniques have failed to produce a solution. In addition, many applications have been mandated to use the Ada programming language for all implementation software, including the knowledge-based components. This thesis identifies three essential requirements needed to support the construction of these systems: first, the need to provide a library of Ada knowledge-based components that supports a variety of knowledge representation paradigms to model the diverse expert domains being encountered in complex applications; second, the need to provide the user with the means of creating and controlling multiple independent instances of the knowledge-based components to cope with the complexity and scale of the implementations; and third, the need to provide an integrating architecture in which the knowledge-based components may be embedded directly into an application environment. These requirements have been satisfied by using ideas derived from the concept of abstract data types to construct a library of knowledge-based components; the components have been called abstract knowledge types. Subsequently, multiple instances of the abstract knowledge types have been integrated in modules called knowledge sources, which model specific problem knowledge domains. The knowledge sources have been used to construct a blackboard architecture. The abstract knowledge types have been used to build a prototype university timetabling system in order to demonstrate their use. The research has shown that the abstract knowledge type integration approach results in a uniform implementation strategy for both conventional and knowledge-based components

Renewal of a linear electrical network simulator into Ada

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment Of the requirements for the degree of Master of Science in Engineering. Johannesburg, 1993Renewal is the extraction of the intellectual content (algorithms, data structures) from an existing program, and then puilding a new more maiatainable program using more modem progra1Tlming methods and languages. A survey of software structure on maintenance. highlighted the different hierarchies produced by functional and object-oriented design methods. Elecsim, a linear circuit sL~ulator written in Pascal, was chosen as the existing program to be renewed, The new version follows the approach of decoupling the user interface and introducing an explicit scheduler. The object-oriented design technique is used extensively. Other issues addressed include online-help and. documentation for the program. Conclusions are drawn which are generally applicable from the specificlessons learnt from the Elecsim/Elector case study.MT201