Detection of separable predicates on series-parallel systems

In this thesis, we address part of the predicate detection problem on distributed computations. We introduce two new classes of predicates, the monotonic predicates and the separable predicates. These classes generalize several classes of well-known predicates as the conjunctive predicates. We show that these classes are detected efficiently on distributed computations having the series-parallel property. This deviates from the approach used in the past where the detection problem was addressed for small classes of predicates to be detected on general distributed computations. The detection algorithm is based on a decomposition of the state lattice into simple subsets called concurrent intervals. This decomposition has its own interest since it helps understanding the relation between the complexity of the state lattice and the complexity of the event structure. At the heart of this relation is a new structure: the communication graph. We show that the communication graph gives a suitable level of abstraction to deal with the predicate detection problem

Geographic Concentration as a Dynamic Process

The degree of geographic concentration of individual manufacturing industries in the U.S. has declined only slightly in the last twenty years. At the same time, new plant births, plant expansions, contractions and closures have shifted large quantities of employment across plants, firms, and locations. This paper uses data from the Census Bureau's Longitudinal Research Database to examine how relatively stable levels of geographic concentration emerge from this dynamic process. While industries' agglomeration levels tend to remain fairly constant, we find that there is greater variation in the locations of these agglomerations. We then decompose aggregate concentration changes into portions attributable to plant births, expansions, contractions, and closures, and find that the location choices of new firms and differences in growth rates have played the most significant role in reducing levels of geographic concentration, while plant closures have tended to reinforce agglomeration. Finally, we look at coagglomeration patterns to test three of Marshall's theories of industry agglomeration: (1) agglomeration saves transport costs by proximity to input suppliers or final consumers, (2) agglomeration allows for labor market pooling, and (3) agglomeration facilitates intellectual spillovers. While there is some truth behind all three theories, we find that industrial location is far more driven by labor mix than by any of the other explanatory variables.

Effect of Tuned Parameters on a LSA MCQ Answering Model

This paper presents the current state of a work in progress, whose objective is to better understand the effects of factors that significantly influence the performance of Latent Semantic Analysis (LSA). A difficult task, which consists in answering (French) biology Multiple Choice Questions, is used to test the semantic properties of the truncated singular space and to study the relative influence of main parameters. A dedicated software has been designed to fine tune the LSA semantic space for the Multiple Choice Questions task. With optimal parameters, the performances of our simple model are quite surprisingly equal or superior to those of 7th and 8th grades students. This indicates that semantic spaces were quite good despite their low dimensions and the small sizes of training data sets. Besides, we present an original entropy global weighting of answers' terms of each question of the Multiple Choice Questions which was necessary to achieve the model's success.Comment: 9 page

Killing spinors and spectral properties of the Dirac operator

A survey of the spectral properties of the classical Dirac operator on a Riemannian spin manifold is made. Killing spinors, which are special eigenfunctions of the Dirac operator, are studied and necessary conditions for their existence are given. Killing spinors on $IR sp{n}$, $S sp{n}$ and $H sp{n}$ are also computed explicitly. Finally the transformation law for Dirac operator under conformal change of the metric is computed and a lower bound for the eigenvalues is given

Revue d'histoire du Bas Saint-Laurent, vol. 6 (2-3)

Éditorial: Du deux en un -- Mot de présentation -- Quelques jalons historiques de notre développement -- L'Est du Québec se rappelle du mouvement des années trente -- L'église de Rimouski et le développement régional : 1963-1972 -- Entrevue avec Pierre Jobin du CRD -- L'OPDQ et le développement régional selon Gendron Jean-Paul -- La naissance d'un mouvement populaire dans l'Est du Québec -- Formulation collective d'une "Formation" en développement régiona