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Thesis (Ph. D.)--University of Kentucky, 2001. / Title from document title page. Document formatted into pages; contains vii, 121 p. : ill. Includes abstract. Includes bibliographical references (p. 116-119).

Thesis (M.S.)--Rochester Institute of Technology, 1989. / "References": leaves 26-28.

Thesis (MSc (Hons.)) -- University of Western Sydney, Nepean, 2000. / "A thesis submitted for the degree of Master of Science (Honours)-Computing at University of Western Sydney - Nepean" Includes bibliographical references (leaves 117-121).

Thesis (M.S.)--Oregon Graduate Center, 1987.

The expressive power of logic-programming languages allows utilization of conventional constructs in development of computer systems based on logic programming. However, logic-programming languages have many novel features and capabilities. This thesis investigates how advantage can be taken of these features in the development of a logic-based computer system. It demonstrates that innovative approaches to software, hardware, and computer system design and implementation are feasible in a logic-programming context and often preferable to adaptation of conventional ones. The investigation centers on three main ideas: executable specification, declarative I/O, and implementation through transformation and meta-interpretation. A particular class of languages supporting parallel computation, committed-choice logic-programming languages, are emphasized. One member of this class, Concurrent Prolog, serves as the machine, specification, and implementation language. The investigation has several facets. Hardware, software, and overall system models for a logic-based computer are determined and examined. The models are described by logic programs. The computer system is represented as a goal for resolution. The clauses involved in the subsequent reduction steps constitute its specification. The same clauses also describe the manner in which the computer system is initiated. Frameworks are given for developing models of peripheral devices whose actions and interactions can be declaratively expressed. Interactions do not rely on side-effects or destructive assignment, and are term-based. A methodology is presented for realizing (prototypic) implementations from device specifications. The methodology is based on source-to-source transformation and meta-interpretation. A magnetic disk memory is used as a representative example, resulting in an innovative approach to secondary storage in a logic-programming environment. Building on these accomplishments, a file system for a logic-based computer system is developed. The file system follows a simple model and supports term-based, declarative I/O. Throughout the thesis, features of the logic-programming paradigm are demonstrated and exploited. Interesting and innovative concepts established include: device processes and device processors; restartable and perpetual devices and systems; peripheral devices modelled as function computations or independent logical (inference) systems; unique, compact representations of terms; lazy term expansion; files systems as perpetual processes maintaining local states; and term- and unification-based file abstractions. Logic programs are the sole formalism for specifications and implementations. / Science, Faculty of / Computer Science, Department of / Graduate

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The general area of developing, applying and studying new and parallel models of computation is motivated by a need to overcome the limits of current Von Neumann based architectures. A key area of research in understanding how new technology can be applied to Al problem solving is through using logic languages. Logic programming languages provide a procedural interpretation for sentences of first order logic, mainly using a class of sentence called Horn clauses. Horn clauses are open to a wide variety of parallel evaluation models, giving possible speed-ups and alternative parallel models of execution. The research in this thesis is concerned with investigating one class of parallel logic language known as Committed Choice Non-Deterministic languages. The investigation considers the inherent parallel behaviour of Al programs implemented in the CCND languages and the effect of various alternatives open to language implementors and designers. This is achieved by considering how various Al programming techniques map to alternative language designs and the behaviour of these Al programs on alternative implementations of these languages. The aim of this work is to investigate how Al programming techniques are affected (qualitatively and quantitatively) by particular language features. The qualitative evaluation is a consideration of how Al programs can be mapped to the various CCND languages. The applications considered are general search algorithms (which focuses on the committed choice nature of the languages); chart parsing (which focuses on the differences between safe and unsafe languages); and meta-level inference (which focuses on the difference between deep and flat languages). The quantitative evaluation considers the inherent parallel behaviour of the resulting programs and the effect of possible implementation alternatives on this inherent behaviour. To carry out this quantitative evaluation we have implemented a system which improves on the current interpreter based evaluation systems. The new system has an improved model of execution and allows several

With 92% of today’s browsers supporting WebAssembly the need for decompilers to discover malicious code is greater than ever. The introduction of the Datalog to C++ compiler Soufflé, in 2016, enables the implementation of effective Datalog-based decompilers. This thesis investigates if a Datalogbased approach to decompilation can be used to implement a WebAssembly decompiler. Such a decompiler is implemented and then evaluated in terms of decompilability, recompilabilty and semantic equivalence using randomly generated programs of various complexity. Each generated program is first decompiled, then recompiled if the decompilation was successful, and finally executed if the recompilation was successful. The results showed that the implementation can decompile all generated programs and that most of the decompiled programs are recompilable. However, only 70% of the lowest complexity programs maintained the output of the original program. As the complexity increased this percentage fell below 20%, a result of more complex programs being more likely to contain code structures that are not handled correctly. If the similarity of the decompiled programs were instead measured by recompiling the decompiled programs to WebAssembly and observing the number of instructions differing from the original WebAssembly binary the percentages were slightly more satisfying with the percentage of instructions differing ranging from 25% for the lowest complexity programs to 65% for the highest complexity programs. While the results are not distinct enough to draw the conclusion that a Datalog-based approach to decompilation is suitable for implementing a WebAssembly decompiler they instigate the need for further research on the topic, e.g. by supporting more WebAssembly instructions as well as supporting WebAssembly binaries compiled from other languages than C. / Idag stödjer 92% av alla webbläsare WebAssembly och behovet av dekompilatorer för att upptäcka skadlig kod är större än någonsin. Datalog-kompilatorn Soufflé som introducerades 2016 gjorde det möjligt att implementera effektiva Datalog-baserade dekompilatorer. Detta arbete undersöker om en Datalogbaserad dekompilator kan användas för att implementera en WebAssemblydekompilator. Detta genomförs genom att en Datalog-baserad WebAssemblydekompilator implementeras och sedan utvärderas i termer av dekompilerbarhet, återkompilerbarhet och semantisk ekvivalens med hjälp av slumpmässigt genererade program av varierande komplexitet. Varje genererat program dekompileras och kompileras sedan igen för att slutligen exekveras. Resultaten visade att dekompilatorn kunde dekompilera alla genererade program och att de flesta av de dekompilerade programmen var omkompilerbara. Däremot gav endast 70% av programmen med lägst komplexitet samma utdata som respektive ursprungsprogram. När komplexiteten ökade sjönk denna procentsats till under 20%, en följd av att program av en högre komplexitet i högre grad innehåller kodstrukturer som hanteras felaktigt. Om likheten mellan de dekompilerade programmen istället mättes genom att kompilera om de dekompilerade programmen till WebAssembly och titta på antalet instruktioner som skiljer sig från den ursprungliga WebAssembly-binären var resultaten något mer tillfredsställande med endast 25%’s skillnad för programmen med lägst komplexitet upp till 65%’s skillnad för programmen med högst komplexitet. Trots att resultaten inte är tillräckligt tydliga för att dra slutsatsen att en Datalog-baserad dekompilator är lämplig för att implementera en WebAssembly-dekompilator, tydliggör de behovet av vidare forskning på ämnet, t.ex genom att stödja fler WebAssembly-instruktioner samt genom att stödja WebAssembly-binärer kompilerade från andra språk än C.

This thesis implemented a prototype of an expert system shell for support of engineering design activities in the way of logic programming. The development of the system is based on the theoretical framework for knowledge-based system design and the formal modeling concepts. Under the above methodologies, two knowledge representations, production rule system and system entity structure, are incorporated into the knowledge base for figuring design structures. Here the production system scheme is employed for synthesis of design models represented in the system entity structure. The whole system is coded in Turbo Prolog and a specific domain knowledge, namely a local area network, is currently used as a testbed environment.