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Rule-based expert systems are increasingly used to monitor and control the operations of complex real-time systems which require intensive knowledge-decision processing and human expertise. These embedded Al systems must respond to events in the rapidly changing external environment so that the results of the expert system's computation in each monitor-respond cycle are valid in safely operating the real-time system. Determining how fast an expert system can respond under all possible situations is a difficult problem. We have developed an efficient analysis methodology for a large class of rule-based EQL programs to determine whether a program in this class has bounded response time. In particular, we have identified several sets of primitive behavioral constraint assertions: an EQL program which satisfies all constraints in one of these sets of assertions is guaranteed to have bounded response time. Here, we enhance the applicability of our analysis technique by introducing a facility with which the rule-based programmer can specify application-specific knowledge that is too difficult to be mechanically detected in the new language Estella in order to determine the performance of an even wider range of programs. We also describe efficient algorithms for implementing the analysis tools. [ABSTRACT FROM AUTHOR]

This paper reports on the initial experimental evaluation of the Reusability-Oriented Parallel programming Environment (ROPE), a software component reuse system developed at the University of Texas at Austin. ROPE helps the designer find and understand components by using a new classification method called structured relational classification. ROPE is a part of a development environment for parallel programs which uses a declarative/hierarchical graphical programming interface. This interface allows use of components with different levels of abstraction, ranging from design units to actual code modules. ROPE supports reuse of all of the component types defined in the development environment. The experimental design included metrics such as fraction of code in a program consisting of reused components, development time and error rates, and qualitative metrics such as user satisfaction and user perceived utility. The subjects for the experiments were undergraduate and graduate students in the Departments of Computer Sciences and Electrical and Computer Engineering. The development time was drastically cut for all programs and the average fraction of code in a given program which was reused from the ROPE library was about 80 percent. Programs developed with the aid of ROPE were found to have error rates far less than those developed without ROPE. These results, while gratifying, are not surprising. They show that ROPE attains a high level of reuse for programs of modest size and complexity. These experiments are the necessary first step in a systematic evaluation of reuse in the CODE/ROPE environment. [ABSTRACT FROM AUTHOR]

This paper proposes a model or paradigm for the development of parallel algorithms, gives an example of the proposed paradigm, and displays algorithms developed by application of the technique. The algorithm for the merge of two ordered fists developed through application of this technique is thought to be original. The paradigm proposed is to create composite unit operations which combine data movement between data structures with a conventional operation such as compare or add. The composite operation constructed for this study is based upon partitioning the data elements into two linear lists. Exchange of data between adjacent elements in each list are then combined with compares and adds to complete the composite operations. This composite operation can be implemented on at least the following computational architectures. 1) SIMD with all processors sharing a common memory. 2) SIMD with local memories and a linear interconnection (circular pipeline or ring network of processors). 3) Vector processor with common memory, such as a CDC CYBER 205 or a Cray Research CRAY-1. The algorithms developed all have the property of linear speed-up with the number of processing elements. The algorithms developed include sorting, merging, selection among sets, set interconnection, set difference, subset testing, and string matching. [ABSTRACT FROM AUTHOR]

Discusses parallel architectures for computer systems. Usefulness of having several parts of a system simultaneously performing different parts of a task; Potential power in the systems; Models of computation; Languages and architectures; Connecting the elements; Commercial architectures; Specialized processors; Future architectures.