Compilation efficace pour FPGA reconfigurable dynamiquement

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

A Compilation Strategy for Numerical Programs Based on Partial Evaluation

This work demonstrates how partial evaluation can be put to practical use in the domain of high-performance numerical computation. I have developed a technique for performing partial evaluation by using placeholders to propagate intermediate results. For an important class of numerical programs, a compiler based on this technique improves performance by an order of magnitude over conventional compilation techniques. I show that by eliminating inherently sequential data-structure references, partial evaluation exposes the low-level parallelism inherent in a computation. I have implemented several parallel scheduling and analysis programs that study the tradeoffs involved in the design of an architecture that can effectively utilize this parallelism. I present these results using the 9- body gravitational attraction problem as an example.

Achieving Real-Time Mode Estimation through Offline Compilation

As exploration of our solar system and outerspace move into the future, spacecraft are being developed to venture on increasingly challenging missions with bold objectives. The spacecraft tasked with completing these missions are becoming progressively more complex. This increases the potential for mission failure due to hardware malfunctions and unexpected spacecraft behavior. A solution to this problem lies in the development of an advanced fault management system. Fault management enables spacecraft to respond to failures and take repair actions so that it may continue its mission. The two main approaches developed for spacecraft fault management have been rule-based and model-based systems. Rules map sensor information to system behaviors, thus achieving fast response times, and making the actions of the fault management system explicit. These rules are developed by having a human reason through the interactions between spacecraft components. This process is limited by the number of interactions a human can reason about correctly. In the model-based approach, the human provides component models, and the fault management system reasons automatically about system wide interactions and complex fault combinations. This approach improves correctness, and makes explicit the underlying system models, whereas these are implicit in the rule-based approach. We propose a fault detection engine, Compiled Mode Estimation (CME) that unifies the strengths of the rule-based and model-based approaches. CME uses a compiled model to determine spacecraft behavior more accurately. Reasoning related to fault detection is compiled in an off-line process into a set of concurrent, localized diagnostic rules. These are then combined on-line along with sensor information to reconstruct the diagnosis of the system. These rules enable a human to inspect the diagnostic consequences of CME. Additionally, CME is capable of reasoning through component interactions automatically and still provide fast and correct responses. The implementation of this engine has been tested against the NEAR spacecraft advanced rule-based system, resulting in detection of failures beyond that of the rules. This evolution in fault detection will enable future missions to explore the furthest reaches of the solar system without the burden of human intervention to repair failed components.

Compilation of documents for the development of a state of art of the investigation of perdurability

A través del estudio y la investigación basados en bibliografía de diversas nacionalidades que data desde la década de los setenta hasta la actualidad, ha sido posible analizar la tendencia académica de las investigaciones acerca la Perdurabilidad. Esta recolección de estudios es una fuente de información para todos aquellos que deseen tener un entendimiento más profundo acerca de la teoría que sostiene el concepto de Perdurabilidad. A lo largo de esta investigación, el lector encontrará un conjunto de varios autores de distintas nacionalidades que abordaron el tema de la Perdurabilidad bajo alguna de sus concepciones (longevidad, resistencia, supervivencia); lo que permite tener una visión más amplia acerca de la importancia de ciertos estudios de acuerdo a su origen y contexto cultural. Es importante resaltar que esta investigación es netamente teórica con el propósito de aclarar el concepto de Perdurabilidad y facilitar futuras investigaciones acerca de este tema

Reusability of dictionaries in the compilation of NLP lexicons

This paper discusses particular linguistic challenges in the task of reusing published dictionaries, conceived as structured sources of lexical information, in the compilation process of a machine-tractable thesaurus-like lexical database for Brazilian Portuguese. After delimiting the scope of the polysemous term thesaurus, the paper focuses on the improvement of the resulting object by a small team, in a form compatible with and inspired by WordNet guidelines, comments on the dictionary entries, addresses selected problems found in the process of extracting the relevant lexical information form the selected dictionaries, and provides some strategies to overcome them.