Cette thèse est consacrée à l'etude de l'implantation du parallélisme OU en Prolog sur des machines sans mémoire commune. Nous présentons le modèle multi-séquentiel OU Opera, implanté par compilation (machine abstraite de Warren - WAM), en préservant la sémantique de Prolog. Les deux problèmes principaux d'un tel système, la gestion de contextes multiples et l'ordonnancement, sont détaillés. La gestion des contextes multiples s'effectue par copie incrémentale, en parallèle au calcul. Pour que ceci reste efficace et cohérent, le traitement des variables conditionnelles a été inclus dans la WAM. Notre méthode introduit une nouvelle pile pour ces variables dont l'initialisation, la déliaison été modifiées. Le coût des opérations séquentielles de la WAM est constant et indépendent du nombre de processus. Nous proposons encore une méthode simple et efficace pour la réalisation de la coupure. Un prototype Opera a été implanté sur un réseau de Transputers. Dans ce prototype, l'ordonnancement a été résolu par une méthode basée sur des heuristiques d'évaluation de charge. Cet ordonnancement est mis en ocuvre par une architecture centralisée où un processus ordonnanceur unique régule la charge des autres processus. L'ordonnanceur utilise une répresentation approximative de l'état du système. La partie séquentielle du prototype Opera constitue l'un des systèmes Prolog les plus efficaces existant actuellement sur le Transputer. Ses gains de performance en parallèle sont aussi effectifs. / This thesis is dedicated to the study of the implementation of Or-parallel Prolog over distributed memory machines. The Opera Or multi-sequential model is presented. It uses compiling techniques (Warren Abstract Machine) and preserves the Prolog semantics. Multienvironment management and scheduling, the two major problems of Opera, are described. Multi-environment management is realized by incremental copying, in parallel to the computation. The treatment of conditional variables is included in the WAM, in order to allow an efficient and coherent cooperation. Our method introduces a new pile for these variables, initialization, binding and unbinding of which are adapted. The cost of WAM sequential operations is constant and independent of the number of processes. We also propose a simple and efficient method for implementing cut in parallel. An Opera prototype has been implemented over a Transputer array. In the current prototype, scheduling is resolved by heuristics of load evaluation. This scheduling is centralized, a unique process balancing the load of the other Prolog workers, and using an approximate representation of the state of the system. The Opera prototype is one of the most efficient Prolog implementations on the Transputer, and reaches effective speed-ups in parallel.

Cette thèse est consacrée à l'etude de l'implantation du parallélisme OU en Prolog sur des machines sans mémoire commune. Nous présentons le modèle multi-séquentiel OU Opera, implanté par compilation (machine abstraite de Warren - WAM), en préservant la sémantique de Prolog. Les deux problèmes principaux d'un tel système, la gestion de contextes multiples et l'ordonnancement, sont détaillés. La gestion des contextes multiples s'effectue par copie incrémentale, en parallèle au calcul. Pour que ceci reste efficace et cohérent, le traitement des variables conditionnelles a été inclus dans la WAM. Notre méthode introduit une nouvelle pile pour ces variables dont l'initialisation, la déliaison été modifiées. Le coût des opérations séquentielles de la WAM est constant et indépendent du nombre de processus. Nous proposons encore une méthode simple et efficace pour la réalisation de la coupure. Un prototype Opera a été implanté sur un réseau de Transputers. Dans ce prototype, l'ordonnancement a été résolu par une méthode basée sur des heuristiques d'évaluation de charge. Cet ordonnancement est mis en ocuvre par une architecture centralisée où un processus ordonnanceur unique régule la charge des autres processus. L'ordonnanceur utilise une répresentation approximative de l'état du système. La partie séquentielle du prototype Opera constitue l'un des systèmes Prolog les plus efficaces existant actuellement sur le Transputer. Ses gains de performance en parallèle sont aussi effectifs. / This thesis is dedicated to the study of the implementation of Or-parallel Prolog over distributed memory machines. The Opera Or multi-sequential model is presented. It uses compiling techniques (Warren Abstract Machine) and preserves the Prolog semantics. Multienvironment management and scheduling, the two major problems of Opera, are described. Multi-environment management is realized by incremental copying, in parallel to the computation. The treatment of conditional variables is included in the WAM, in order to allow an efficient and coherent cooperation. Our method introduces a new pile for these variables, initialization, binding and unbinding of which are adapted. The cost of WAM sequential operations is constant and independent of the number of processes. We also propose a simple and efficient method for implementing cut in parallel. An Opera prototype has been implemented over a Transputer array. In the current prototype, scheduling is resolved by heuristics of load evaluation. This scheduling is centralized, a unique process balancing the load of the other Prolog workers, and using an approximate representation of the state of the system. The Opera prototype is one of the most efficient Prolog implementations on the Transputer, and reaches effective speed-ups in parallel.

Cette thèse est consacrée à l'etude de l'implantation du parallélisme OU en Prolog sur des machines sans mémoire commune. Nous présentons le modèle multi-séquentiel OU Opera, implanté par compilation (machine abstraite de Warren - WAM), en préservant la sémantique de Prolog. Les deux problèmes principaux d'un tel système, la gestion de contextes multiples et l'ordonnancement, sont détaillés. La gestion des contextes multiples s'effectue par copie incrémentale, en parallèle au calcul. Pour que ceci reste efficace et cohérent, le traitement des variables conditionnelles a été inclus dans la WAM. Notre méthode introduit une nouvelle pile pour ces variables dont l'initialisation, la déliaison été modifiées. Le coût des opérations séquentielles de la WAM est constant et indépendent du nombre de processus. Nous proposons encore une méthode simple et efficace pour la réalisation de la coupure. Un prototype Opera a été implanté sur un réseau de Transputers. Dans ce prototype, l'ordonnancement a été résolu par une méthode basée sur des heuristiques d'évaluation de charge. Cet ordonnancement est mis en ocuvre par une architecture centralisée où un processus ordonnanceur unique régule la charge des autres processus. L'ordonnanceur utilise une répresentation approximative de l'état du système. La partie séquentielle du prototype Opera constitue l'un des systèmes Prolog les plus efficaces existant actuellement sur le Transputer. Ses gains de performance en parallèle sont aussi effectifs. / This thesis is dedicated to the study of the implementation of Or-parallel Prolog over distributed memory machines. The Opera Or multi-sequential model is presented. It uses compiling techniques (Warren Abstract Machine) and preserves the Prolog semantics. Multienvironment management and scheduling, the two major problems of Opera, are described. Multi-environment management is realized by incremental copying, in parallel to the computation. The treatment of conditional variables is included in the WAM, in order to allow an efficient and coherent cooperation. Our method introduces a new pile for these variables, initialization, binding and unbinding of which are adapted. The cost of WAM sequential operations is constant and independent of the number of processes. We also propose a simple and efficient method for implementing cut in parallel. An Opera prototype has been implemented over a Transputer array. In the current prototype, scheduling is resolved by heuristics of load evaluation. This scheduling is centralized, a unique process balancing the load of the other Prolog workers, and using an approximate representation of the state of the system. The Opera prototype is one of the most efficient Prolog implementations on the Transputer, and reaches effective speed-ups in parallel.

[pt] Esta tese investiga os fatores semânticos e sintáticos que afetam a codificação do objeto direto anafórico (ODA) no português brasileiro (PB). O ODA pode ser um DP pleno [+ definido], um clítico acusativo, um pronome tônico ou um elemento nulo (cuja natureza é controversa na teoria linguística). Busca-se: (i) avaliar como fatores semânticos (animacidade, especificidade e gênero conceitual), sintáticos (função sintática) e pertinentes à interface sintaxe/semântica (papel temático) afetam a codificação da retomada, em diferentes contextos sintáticos (sentenças simples e ilha sintática) e/ou discursivos (respostas a perguntas QU e complementação de narrativas curtas ou conversas informais); (ii) verificar a influência da escolarização nas estratégias de codificação do ODA; e (iii) discutir a natureza das formas nulas produzidas. O aporte teórico parte da concepção de língua veiculada no Programa Minimalista (CHOMSKY,1995. 2005) e da perspectiva de produção trazida do modelo de computação gramatical em tempo real (CORRÊA, 2006; 2008; CORRÊA; AUGUSTO, 2007; em diante) no tratamento das questões ligadas à acessibilidade relativa do antecedente a ser retomado (ARIEL, 2001; ARNOLD, 2010; BOCK; WARREN, 1985; SANDERS; GERNSBACHER, 2004), quando da codificação gramatical do enunciado (LEVELT, 1989). Parte-se da hipótese de que a produção de ODAs é função das condições de processamento às quais o falante está submetido e que propriedades semânticas e sintáticas do antecedente afetam sua acessibilidade relativa, impondo restrições à codificação de sua retomada. Seis experimentos de produção eliciada são reportados. O contexto sintático influenciou a acessibilidade dos antecedentes, retomados predominantemente por DPs completos entre sentenças no discurso; e por formas mínimas (pronominais e elementos nulos), quando em sentenças complexas. Os efeitos de animacidade e de especificidade sugerem que o pronome tônico seja default para antecedentes acessíveis [+animado; +específico], enquanto o nulo o é para [-animados; mais ou menos específico], corroborando achados da literatura com produção espontânea. O gênero conceitual não foi decisivo para a retomada anafórica, mas pareceu aumentar a especificidade de antecedentes cujo gênero conceitual era conhecido. O papel temático, por si só, não é decisivo para a forma da retomada anafórica. Entretanto, a possibilidade de o elemento nulo recuperar um fato/evento descrito anteriormente o compatibiliza com uma alternativa ao clítico sentencial. O grau de escolaridade dos participantes elevou as taxas de clíticos acusativos, especialmente com antecedentes [+animado] (como alternativa aos pronomes tônicos), evidenciando a interferência da língua escrita sobre a língua falada, bem como a produtividade dessa forma para falantes com alto grau de escolaridade. A função sintática do antecedente não interferiu no ODA. A ocorrência do elemento nulo em contextos de ilha corrobora a visão de que este não seja uma variável no PB. À luz do modelo de computação em tempo real, considera-se que as condições de acesso do antecedente determinam a natureza da forma nula: se a representação da estrutura sintática do antecedente se mantiver ativa na memória de trabalho, este pode ser recuperado como uma elipse, a ser restaurada na interface semântica; se apenas seus traços phi ou a representação semântica de seu antecedente são acessíveis, ODA é codificado como pro. / [en] This thesis investigates the semantic and syntactic factors that affect the encoding of the anaphoric direct object (ADO) in Brazilian Portuguese (BP). The ADO can be a full DP [+definite], an accusative clitic, a stressed pronoun, or a null element (whose nature is controversial in linguistic theory). This research aims to: (i) investigate how the semantic properties (animacy, specificity and conceptual genre) of the antecedent, its syntactic function and factors pertaining to the syntax/semantic interface (thematic role) affect the encoding of the ADO in different syntactic contexts (simple sentences and syntactic island) and/or discourse (answers to WH-questions and continuations of short narratives or informal conversations); (ii) verify the influence of schooling in the strategies of ADO encoding; and (iii) discuss the nature of the null forms produced. The theoretical background incorporates the conception of language conveyed in the Minimalist Program (CHOMSKY, 1995; 2005) and an approach to issues regarding the relative accessibility of the antecedent to be resumed (ARIEL, 2001; ARNOLD, 2010; BOCK; WARREN, 1985; SANDERS; GERNSBACHER, 2004) in the grammatical encoding of a sentence (LEVELT, 1989), in the light of an on-line model of grammatical computation (CORREA, 2006; 2008; CORREA; AUGUSTO, 2007) The working hypothesis is that the production of the ODA is a function of particular processing conditions and that the semantic and syntactic properties of the antecedent affect its relative accessibility, imposing restrictions on its resumption. Six elicited production experiments are reported. The syntactic context influenced the accessibility of the antecedents, predominantly recovered by full DPs, when between-sentences in the discourse; and by minimal forms (pronominals and null elements) in complex sentences. The effects of animacy and of specificity corroborate spontaneous production data, suggesting that the full pronoun is the default option for [+animated; +specific], while the null form is the default option for [-animated; +- specific] antecedents. The conceptual genre of the antecedent was not decisive for a particular form of encoding, but it seemed to enhance the specificity of the antecedent whose conceptual gender was known. The thematic role, by itself, does not determine the form of anaphoric resumption. However, the possibility of the null resumption of an fact/event previously mentioned makes it compatible with an alternative to the sentential clitic. Schooling increased the rates of accusative clitics, especially with [+animated] antecedents (as an alternative to tonic pronouns), showing the interference of the written language on the spoken language, as well as the productivity of this form for educated speakers. The syntactic function of the antecedent did not affect ADO production. The occurrence of the null element in island contexts corroborates the view that the null element is not a variable in BP. It is argued, in the light of the on-line model, that the accessibility of the antecedent determines the nature of null element: if the representation of the syntactic structure of the antecedent is still active in working memory, it can be retrieved as an ellipsis, to be restored at the semantic interface; if it is the phi features of the antecedent or the semantic representation of its referent that remain available, ADO is encoded as a pro.