983 resultados para answer set programming
Resumo:
Technological limitations and power constraints are resulting in high-performance parallel computing architectures that are based on large numbers of high-core-count processors. Commercially available processors are now at 8 and 16 cores and experimental platforms, such as the many-core Intel Single-chip Cloud Computer (SCC) platform, provide much higher core counts. These trends are presenting new sets of challenges to HPC applications including programming complexity and the need for extreme energy efficiency.In this work, we first investigate the power behavior of scientific PGAS application kernels on the SCC platform, and explore opportunities and challenges for power management within the PGAS framework. Results obtained via empirical evaluation of Unified Parallel C (UPC) applications on the SCC platform under different constraints, show that, for specific operations, the potential for energy savings in PGAS is large; and power/performance trade-offs can be effectively managed using a cross-layerapproach. We investigate cross-layer power management using PGAS language extensions and runtime mechanisms that manipulate power/performance tradeoffs. Specifically, we present the design, implementation and evaluation of such a middleware for application-aware cross-layer power management of UPC applications on the SCC platform. Finally, based on our observations, we provide a set of recommendations and insights that can be used to support similar power management for PGAS applications on other many-core platforms.
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Trans-apical aortic valve replacement (AVR) is a new and rapidly growing therapy. However, there are only few training opportunities. The objective of our work is to build an appropriate artificial model of the heart that can replace the use of animals for surgical training in trans-apical AVR procedures. To reduce the necessity for fluoroscopy, we pursued the goal of building a translucent model of the heart that has nature-like dimensions. A simplified 3D model of a human heart with its aortic root was created in silico using the SolidWorks Computer-Aided Design (CAD) program. This heart model was printed using a rapid prototyping system developed by the Fab@Home project and dip-coated two times with dispersion silicone. The translucency of the heart model allows the perception of the deployment area of the valved-stent without using heavy imaging support. The final model was then placed in a human manikin for surgical training on trans-apical AVR procedure. Trans-apical AVR with all the necessary steps (puncture, wiring, catheterization, ballooning etc.) can be realized repeatedly in this setting.
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Large projects evaluation rises well known difficulties because -by definition- they modify the current price system; their public evaluation presents additional difficulties because they modify too existing shadow prices without the project. This paper analyzes -first- the basic methodologies applied until late 80s., based on the integration of projects in optimization models or, alternatively, based on iterative procedures with information exchange between two organizational levels. New methodologies applied afterwards are based on variational inequalities, bilevel programming and linear or nonlinear complementarity. Their foundations and different applications related with project evaluation are explored. As a matter of fact, these new tools are closely related among them and can treat more complex cases involving -for example- the reaction of agents to policies or the existence of multiple agents in an environment characterized by common functions representing demands or constraints on polluting emissions.
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La thématique des désaffiliations religieuses du milieu évangélique est le parent pauvre des études faites jusqu'à ce jour sur ce courant religieux. En effet, l'accent est généralement mis sur son développement en termes d'affiliation faisant alors l'impasse sur les pertes qu'il connaît pourtant. De plus, la question des désaffiliations religieuses est un angle d'approche sociologique particulièrement fécond pour étudier les groupes religieux en permettant, entre autres, de cerner plus en profondeur leur identité, les mécanismes qui favorisent leur pérennisation, mais aussi leur rapport à la société environnante. Dans ce travail, qui s'inscrit en sociologie des religions et qui puise autant dans la littérature sur les désaffiliations religieuses que dans celle des désengagements militants, l'analyse s'est focalisée sur les processus de désengagement au niveau microsociologique : quels sont les motifs qui président les désaffiliations, comment se déroulent ces dernières, quels effets ont-elles sur l'individu en termes identitaires et comment sont-elles perçues par ceux qui restent ? Ces principales questions ont permis de (re] questionner des éléments constitutifs de l'engagement évangélique : les processus de socialisation ; la structuration des liens intragroupe développés par le milieu et son rapport à l'extérieur ; son système normatif; son système de représentation du monde et la démarche religieuse qu'il valorise, qui sont autant d'aspects qui jouent un rôle dans les processus de désaffiliation. Plus précisément, ces éléments agissent en tant que mécanismes de rétention tant sociaux que psychologiques compliquant ainsi le désengagement. Cette thèse s'est construite sur dix-sept entretiens semi directifs menés auprès de personnes ayant grandi pour la plupart dans une famille évangélique et qui ont décidé, un jour, de ne plus fréquenter ce milieu religieux. Pour élargir la perspective analytique et pour permettre de comprendre et d'expliquer les processus de désaffiliation en lien avec le groupe quitté, un ensemble de septante-huit entretiens semi directifs et de mille cent questionnaires standardisés de membres d'Eglises évangéliques a été mobilisé. Partant des logiques du désengagement, cette thèse affine les connaissances actuelles sur l'évangélisme dans le contexte de la modernité, grâce à l'éclairage inédit qu'elle lui donne. Elle développe également le champ des connaissances sur les désaffiliations religieuses en lui fournissant un nouvel exemple de cas tout en lui offrant une autre façon de théoriser les sorties de groupes religieux qui valorisent un engagement de type militant. - Religious disaffiliations from the evangelical milieu have not yet been investigated. Indeed, former studies have usually focused on the development of the milieu by looking at conversions. However, it appears that the study of the disaffiliation processes may not only give results on the reasons and experiences of those disaffiliating, but also shed light on the attributes and the development of the evangelical milieu itself. The main goal of this thesis was to fill this gap in the literature. From a microsociological approach, this thesis sought to answer the following central question : Why, how and with what effects do individuals leave the evangelical milieu and how is this phenomenon perceived, interpreted and managed by the individuals who leave the evangelical community and by the members of the evangelical milieu? These questions enabled me to investigate the functioning of the evangelical milieu : its processes of socialization ; internal and external relationships ; normative system ; belief system or its religious engagement. This set of aspects can influence and complicate the processes of disaffiliation. The analysis of religious disaffiliation was based on seventeen qualitative interviews with former members of evangelical chrurches who decided, one day, not to attend an evangelical church anymore and who question more or less strongly the « system of evangelical thought ». Seventy-eight qualitative interviews with members of evangelical free churches and a representative survey with members of evangelical free churches (N = 1100] completed the analysis and inserted the individual disengagement in the « milieu's logics ». This thesis complements and enriches the literature on evangelism as well as on religious disaffiliation in general.
Resumo:
HIV virulence, i.e. the time of progression to AIDS, varies greatly among patients. As for other rapidly evolving pathogens of humans, it is difficult to know if this variance is controlled by the genotype of the host or that of the virus because the transmission chain is usually unknown. We apply the phylogenetic comparative approach (PCA) to estimate the heritability of a trait from one infection to the next, which indicates the control of the virus genotype over this trait. The idea is to use viral RNA sequences obtained from patients infected by HIV-1 subtype B to build a phylogeny, which approximately reflects the transmission chain. Heritability is measured statistically as the propensity for patients close in the phylogeny to exhibit similar infection trait values. The approach reveals that up to half of the variance in set-point viral load, a trait associated with virulence, can be heritable. Our estimate is significant and robust to noise in the phylogeny. We also check for the consistency of our approach by showing that a trait related to drug resistance is almost entirely heritable. Finally, we show the importance of taking into account the transmission chain when estimating correlations between infection traits. The fact that HIV virulence is, at least partially, heritable from one infection to the next has clinical and epidemiological implications. The difference between earlier studies and ours comes from the quality of our dataset and from the power of the PCA, which can be applied to large datasets and accounts for within-host evolution. The PCA opens new perspectives for approaches linking clinical data and evolutionary biology because it can be extended to study other traits or other infectious diseases.
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Between the end of August and December 2013, an internet based survey named ANSWER will collect data about sexual health, sexual behavior and risk taking among Sub-Saharan African migrants (SSAm) living in Switzerland. This research is carried out by the Institut de médecine sociale et préventive (IUMSP, Lausanne) on a mandate from the Federal Offi ce of Public Health (FOPH), in cooperation with the Swiss Aids Federation (AHS) and other institutions addressing the prevention and information needs of the African population living in Switzerland.
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Background: Microarray data is frequently used to characterize the expression profile of a whole genome and to compare the characteristics of that genome under several conditions. Geneset analysis methods have been described previously to analyze the expression values of several genes related by known biological criteria (metabolic pathway, pathology signature, co-regulation by a common factor, etc.) at the same time and the cost of these methods allows for the use of more values to help discover the underlying biological mechanisms. Results: As several methods assume different null hypotheses, we propose to reformulate the main question that biologists seek to answer. To determine which genesets are associated with expression values that differ between two experiments, we focused on three ad hoc criteria: expression levels, the direction of individual gene expression changes (up or down regulation), and correlations between genes. We introduce the FAERI methodology, tailored from a two-way ANOVA to examine these criteria. The significance of the results was evaluated according to the self-contained null hypothesis, using label sampling or by inferring the null distribution from normally distributed random data. Evaluations performed on simulated data revealed that FAERI outperforms currently available methods for each type of set tested. We then applied the FAERI method to analyze three real-world datasets on hypoxia response. FAERI was able to detect more genesets than other methodologies, and the genesets selected were coherent with current knowledge of cellular response to hypoxia. Moreover, the genesets selected by FAERI were confirmed when the analysis was repeated on two additional related datasets. Conclusions: The expression values of genesets are associated with several biological effects. The underlying mathematical structure of the genesets allows for analysis of data from several genes at the same time. Focusing on expression levels, the direction of the expression changes, and correlations, we showed that two-step data reduction allowed us to significantly improve the performance of geneset analysis using a modified two-way ANOVA procedure, and to detect genesets that current methods fail to detect.
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Business processes designers take into account the resources that the processes would need, but, due to the variable cost of certain parameters (like energy) or other circumstances, this scheduling must be done when business process enactment. In this report we formalize the energy aware resource cost, including time and usage dependent rates. We also present a constraint programming approach and an auction-based approach to solve the mentioned problem including a comparison of them and a comparison of the proposed algorithms for solving them
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Background: The variety of DNA microarray formats and datasets presently available offers an unprecedented opportunity to perform insightful comparisons of heterogeneous data. Cross-species studies, in particular, have the power of identifying conserved, functionally important molecular processes. Validation of discoveries can now often be performed in readily available public data which frequently requires cross-platform studies.Cross-platform and cross-species analyses require matching probes on different microarray formats. This can be achieved using the information in microarray annotations and additional molecular biology databases, such as orthology databases. Although annotations and other biological information are stored using modern database models ( e. g. relational), they are very often distributed and shared as tables in text files, i.e. flat file databases. This common flat database format thus provides a simple and robust solution to flexibly integrate various sources of information and a basis for the combined analysis of heterogeneous gene expression profiles.Results: We provide annotationTools, a Bioconductor-compliant R package to annotate microarray experiments and integrate heterogeneous gene expression profiles using annotation and other molecular biology information available as flat file databases. First, annotationTools contains a specialized set of functions for mining this widely used database format in a systematic manner. It thus offers a straightforward solution for annotating microarray experiments. Second, building on these basic functions and relying on the combination of information from several databases, it provides tools to easily perform cross-species analyses of gene expression data.Here, we present two example applications of annotationTools that are of direct relevance for the analysis of heterogeneous gene expression profiles, namely a cross-platform mapping of probes and a cross-species mapping of orthologous probes using different orthology databases. We also show how to perform an explorative comparison of disease-related transcriptional changes in human patients and in a genetic mouse model.Conclusion: The R package annotationTools provides a simple solution to handle microarray annotation and orthology tables, as well as other flat molecular biology databases. Thereby, it allows easy integration and analysis of heterogeneous microarray experiments across different technological platforms or species.
Resumo:
Møller-Plesset (MP2) and Becke-3-Lee-Yang-Parr (B3LYP) calculations have been used to compare the geometrical parameters, hydrogen-bonding properties, vibrational frequencies and relative energies for several X- and X+ hydrogen peroxide complexes. The geometries and interaction energies were corrected for the basis set superposition error (BSSE) in all the complexes (1-5), using the full counterpoise method, yielding small BSSE values for the 6-311 + G(3df,2p) basis set used. The interaction energies calculated ranged from medium to strong hydrogen-bonding systems (1-3) and strong electrostatic interactions (4 and 5). The molecular interactions have been characterized using the atoms in molecules theory (AIM), and by the analysis of the vibrational frequencies. The minima on the BSSE-counterpoise corrected potential-energy surface (PES) have been determined as described by S. Simón, M. Duran, and J. J. Dannenberg, and the results were compared with the uncorrected PES
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A comparision of the local effects of the basis set superposition error (BSSE) on the electron densities and energy components of three representative H-bonded complexes was carried out. The electron densities were obtained with Hartee-Fock and density functional theory versions of the chemical Hamiltonian approach (CHA) methodology. It was shown that the effects of the BSSE were common for all complexes studied. The electron density difference maps and the chemical energy component analysis (CECA) analysis confirmed that the local effects of the BSSE were different when diffuse functions were present in the calculations
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The effect of basis set superposition error (BSSE) on molecular complexes is analyzed. The BSSE causes artificial delocalizations which modify the first order electron density. The mechanism of this effect is assessed for the hydrogen fluoride dimer with several basis sets. The BSSE-corrected first-order electron density is obtained using the chemical Hamiltonian approach versions of the Roothaan and Kohn-Sham equations. The corrected densities are compared to uncorrected densities based on the charge density critical points. Contour difference maps between BSSE-corrected and uncorrected densities on the molecular plane are also plotted to gain insight into the effects of BSSE correction on the electron density