This dissertation describes a system that constructs efficient, retargetable code generators and optimizers. chop reads nonprocedural descriptions of a computer's instruction set and of a naive code generator for the computer, and it writes an integrated code generator and peephole optimizer for it. The resulting code generators are very efficient because they interpret no tables; they are completely hard-coded. Nor do they build complex data structures to communicate between code generation and optimization phases. Interphase communication is reduced to the point that the code generator's output is often encoded in the program counter and conveyed to the optimizer by jumping to the right label. chop's code generator and optimizer are based on a very simple formalism, namely rewriting rules. An instrumented version of the compiler infers the optimization rules as it complies a training suite, and it records them for translation into hard code and inclusion into the production version. I have replaced the Portable C Compiler's code generator with one generated by chop. Despite a costly interface, the resulting compiler runs 30% to 50% faster than the original Portable C Compiler (pcc) and generates comparable code. This figure is diluted by common lexical analysis, parsing, and semantic analysis and by comparable code emission. Allowing for these, the new code generator appears to run approximately seven times faster than that of the original pcc.

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"Mémoire présenté à la faculté des études supérieures en vue de l'obtention du grade de maîtrise en droit des affaires LLM" / Ce mémoire analyse l'introduction et l'application de la notion d'entreprise dans le Code de commerce français et dans le Code civil du Québec. En adoptant cette notion, les deux législateurs avaient pour objet principal de pallier à la désuétude de principes traditionnels du droit commercial et d'ajuster leurs législations aux nouvelles mutations économiques et sociales. Ainsi, est évoquée présentement, en France comme au Québec, la notion d'entreprise. Cependant, force est de constater que le rôle donné à cette notion de même que le contexte dans lequel elle s'applique ne sont pas les mêmes dans les deux législations. Dans le C.c.Q., la notion d'entreprise a remplacé définitivement la notion de commerce afin d'élargir le champ d'application des règles dérogatoires propres au monde des affaires. Quant au législateur français, bien qu'il ait introduit l'entreprise dans la plupart des règles des affaires, il a opté pour le maintien du droit commercial. Dès lors, l'accent sera mis sur la méthode poursuivie par chacune des deux législations quant à l'adoption et l'application de la notion d'entreprise ainsi que sur les difficultés et les avantages inhérents à chaque démarche. La conclusion tirée de cette étude montre que les deux expériences sont aux antipodes l'une de l'autre en ce qui concerne l'état actuel de droit de chaque législation suite à l'adoption de la notion d'entreprise. En gardant la notion de commerce, le législateur français profite toujours d'une stabilité juridique certaine dérivant notamment d'un bagage doctrinal et jurisprudentiel notable, lié au droit commercial. Toutefois, cette stabilité est faite au détriment d'une structure juridique cohérente et logique. Par contre, le C.c.Q. repose sur des règles juridiques homogènes et rationnelles dignes d'un système juridique évolué. Cependant, il essuie plusieurs difficultés quant à l'interprétation et l'application de la nouvelle notion, étant donné la nouveauté de la réforme. / An analysis of the implementation of the notion of enterprise in the French Commercial Code and the Civil Code of Quebec is undertaken in this study. By adopting the concept of enterprise, both legislators wanted to overcome the obsolescence of the traditional principles of the commercial law and adjust their legislations to the modem economic and social mutations. Thus, this concept is currently referred to in France and in Quebec. However, it would be a flaw to accept the adoption and implementation of the concept of enterprise as the same in France and in Quebec. Indeed, in the Civil Code of Quebec, the enterprise concept replaced completely the concept of commerce to widen the realm of application of the rules applied in the business world. On the other hand, despite the adoption of this concept on most of the business regulations, the French legislator chose to preserve the commercial law. The emphasis in this thesis is to contrast the two paths taken by France and Quebec to adopt and implement the concept of enterprise and to highlight the advantages and disadvantages of each path. This study concludes that the two experiences are in contradiction with regard to the current state of law in France and in Quebec after adopting the notion of enterprise. By safeguarding the notion of commerce, the French legislator still profiting from stable juridical system derived essentially from the commercial law's doctrine and jurisprudence. However, this stability was maintained at the cost of a logical and coherent legal structure. On the other hand, the Civil Code of Quebec is based on rational and homogeneous rules that correspond to a modern legal system. Nevertheless, given the novelty of the legal reforms, many challenges arise when it cornes to the application and interpretation of the new concept of enterprise.

M.Sc. / ZnO nanostructures with different morphologies have been prepared by using microwave and conventional heating methods. The effect of solvent, zinc precursor, time and the concentration of sodium hydroxide on the morphology of zinc oxide were investigated, when different heating methods were employed. ZnO nanoparticles were prepared using the solvothermal method. Zinc precursor impact on the shape of zinc oxide nanoparticles formed depends on the solvent used during the synthesis. Different morphologies such as spheres, rods, hexagonal prisms, hexagonal plates, diamond-like and multipods were formed by a simple solution based method. The optical features for most of the formed shapes were typical of ZnO nanoparticles. The XRD patterns of the particles showed the most stable hexagonal phase with a high degree of crystallinity. A capping molecule has an impact on the shape of the nanoparticle. In this work, we also present the results from the study of the effect of the stabilizing molecule on the shape and formation of the core shell nanoparticles of CdSe/PbS. The capping molecules used were hexadecylamine (HDA), tri-n-octylphosphine oxide (TOPO) and stearic acid. The core shell nanomaterials were synthesized by using a method in which selenium powder was converted to TOPSe.Transmission electron microscopy was used to determine the morphology and the size of the ZnO and coreshell nanomaterials. Spherical particles were obtained when TOPO was used whereas the use of HDA induced the formation of non-spherical shapes. With both capping molecules, epitaxial shell growth was not achieved. The particles formed from both capping groups (HDA and TOPO) were large due to the long reaction time that instigates lager particle sizes. However, when stearic acid was used as a capping molecule, a perfect core shell arrangement was formed. The phase and the crystallinity of the formed particles were determined by the XRD.

This project deals with the critical evaluation of a Poisson windowed test signal which was proposed for in-service and production testing of filtered pulse code modulation systems. The Poisson windowed test signal has various advantages over the existing two test methods specified by the International Consultive Committee for Telephone and Telegraph (CCITT). The main goals of the new test signal are to minimise the test time and to accommodate the send- and reel eve filters normally found in communication systems. The evaluation process included the compilation of performance curves of signal ,to noise ratio vs. signal level and gain variation vs. signal level. These curves were compiled by simulating the codec and filters on a digital computer and processing the output data. Three sets of programs were The results obtained revealed some fundamental limitations of the proposed test signal. Using the basic properties of the Poisson windowed signal, an alternative test signal was proposed. It was the single sided exponentially windowed sinusoidal which proved to be suitable for the testing of filtered pulse code modulation stems.

University of Macau / Faculty of Arts and Humanities. / Department of English

University of Macau / Faculty of Arts and Humanities. / Department of English