HAL - Lille 3
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Insula : blog d'une bibliothèque ?
No full textNational audienceLa Bibliothèque des sciences de l'Antiquité (BSA) de l'université Lille 3 a créé un blog en 2010 : Insula. Ce blog, qui s'intéresse principalement à l'Antiquité, sous toutes ses formes, est une publication collaborative. Plus de trente contributeurs y ont en effet publié un ou plusieurs textes : enseignants, personnels des bibliothèques et étudiants. Les aspects formels du blog lui ont valu d'obtenir un ISSN de la part de la Bibliothèque nationale de France.La communication, qui a pour cadre le séminaire sur les humanités numériques organisé par la Mehs de Lille, présente l'histoire de ce blog, son évolution au fil de plus de 400 billets publiés, et la manière dont il s'articule avec le reste des activités d'une bibliothèque universitaire spécialisée. Mais Insula est-il encore le blog d'une bibliothèque
Tractable Lineages on Treelike Instances: Limits and Extensions
No full textInternational audienceQuery evaluation on probabilistic databases is generally intractable (#P-hard). Existing dichotomy results [19, 18, 23] have identified which queries are tractable (or safe), and connected them to tractable lineages [36]. In our previous work [2], using different tools, we showed that query evaluation is linear-time on probabilistic databases for arbitrary monadic second-order queries, if we bound the treewidth of the instance.In this paper, we study limitations and extensions of this result. First, for probabilistic query evaluation, we show that MSO tractability cannot extend beyond bounded treewidth: there are even FO queries that are hard on any efficiently constructible unbounded-treewidth class of graphs. This dichotomy relies on recent polynomial bounds on the extraction of planar graphs as minors [10], and implies lower bounds in non-probabilistic settings, for query evaluation and match counting in subinstance-closed families. Second, we show how to explain our tractability result in terms of lineage: the lineage of MSO queries on bounded-treewidth instances can be represented as bounded-treewidth circuits, polynomial-size OBDDs, and linear-size d-DNNFs. By contrast, we can strengthen the previous dichotomy to lineages, and show that there are even UCQs with disequalities that have superpolynomial OBDDs on all unbounded-treewidth graph classes; we give a characterization of such queries. Last, we show how bounded-treewidth tractability explains the tractability of the inversion-free safe queries: we can rewrite their input instances to have bounded-treewidth.</p
The importance of considering intra-individual variability and inter-individual differences for studying the effect of positive psychology interventions
No full textInternational audienc
A convolution approach for parameters and delay systems identification
No full textInternational audienceThis paper deals with on-line parameters and delay estimation of systems involving retarded phenomena. Using a convolution based approach, it generalizes to arbitrary inputs existing estimation results based on structured ones, while keeping the generalized eigenvalue structure. The proposed estimation algorithms allow for updated estimations, avoiding possible singularities in the matric pencil. Theoretical results are supported by numerical simulation
Are REST APIs for Cloud Computing Well-Designed? An Exploratory Study
No full textInternational audienceCloud computing is currently the most popular model to offer and access computational resources and services. Many cloud providers use the REST architectural style (Representational State Transfer) for offering such computational resources. However, these cloud providers face challenges when designing and exposing REST APIs that are easy to handle by end-users and/or developers. Yet, they benefit from best practices to help them design understandable and reusable REST APIs. However, these best practices are scattered in the literature and they have not be studied systematically on real-world APIs. Consequently, we propose two contributions. In our first contribution, we survey the literature and compile a catalog of 73 best practices in the design of REST APIs making APIs more understandable and reusable. In our secondcontribution, we perform a study of three different and well-known REST APIs from three cloud providers to investigate how their APIs are offered and accessed. These cloud providers are Google Cloud Platform, OpenStack, and Open Cloud Computing Interface (OCCI). In particular, we evaluate the coverage of the features provided by the REST APIsof these cloud providers and their conformance with the best practices for REST APIs design. Our results show that Google Cloud follows 66% (48/73), OpenStack follows 62% (45/73), and OCCI 1.2 follows 56% (41/73) of the best practices. Second, although these numbers are not necessarily high, partly because of the strict and precise specification of best practices, we showed that cloud APIs reach an acceptable level of maturity
Le Vase qui parle : une rencontre inouïe avec l’Antiquité
No full textArticle qui revient sur la genèse du Vase qui parle, sa réalisation, mais aborde également les retombées techniques et économiques ainsi que le rôle du Vase comme ambassadeur de la médiation scientifique en SHS. Ce projet a en effet pu démontrer une fois encore, en particulier au grand public, que l’innovation technologique n’est pas seulement constitutive des sciences et techniques mais qu’elle est également partagée par les sciences humaines et sociales
Biobjective Performance Assessment with the COCO Platform
No full textArXiv e-prints, arXiv:1605.01746This document details the rationales behind assessing the performance of numerical black-box optimizers on multi-objective problems within the COCO platform and in particular on the biobjective test suite bbob-biobj. The evaluation is based on a hypervolume of all non-dominated solutions in the archive of candidate solutions and measures the runtime until the hypervolume value succeeds prescribed target values
Adaptabilité et Encapsulation dans les Langages Dynamiquement Typés: Dompter la Réflexion et les Méthode d'Extension
No full textUsers expect modern software to be both continually available and updated on the fly. Introduction of new features and integration of bug fixes should not trouble the smooth running of an application. Developers also benefit from dynamic mod- ifications of software, e.g. they can adapt code to new unanticipated situations or they can run dynamic analyses to get feedback about the behavior of running applications for monitoring, debugging and optimization purposes. Programming languages and their runtimes should thus provides developers with mechanisms that improve software adaptability.At the same time, the increasing size and complexity of software call for ap- plications made up of many interacting components developed by different parties. In this context, either all components are trusted or each component needs to be properly protected from other ones. For example, a plugin should not be able to manipulate the internal structures or leaks private data of its host application unre- strictedly. Likewise, a malicious library should not be able to corrupt its clients or interfere with their operations. Programming languages should thus provide devel- opers with mechanisms that improve software isolation, such as encapsulation and custom access control policies.The need for dynamic adaptations that can change nearly every aspect of an application on the one hand and the need for properly confined components on the other hand pulls programming language design in two opposite directions: ei- ther more flexibility or more control. This dissertation studies this tension in the context of dynamically-typed object-oriented languages with two language mech- anisms that promote software adaptability: reflection and extension methods. For both mechanisms, we demonstrate their usefulness, their harmful effect on encap- sulation and propose solutions to retain their power while maintaining encapsula- tion.Les utilisateurs s’attendent à ce que les logiciels d’aujourd’hui soient à la fois con- tinuellement disponibles et mis-à-jour à la volée. L’introduction de nouvelles fonc- tionnalités et l’intégration de correctifs ne doit pas perturber la bonne marche d’une application. Les développeurs bénéficient aussi de la modification dynamique des logiciels: par exemple, ils peuvent adapter le code à de nouvelle situations non anticipées ou bien ils peuvent exécuter des analyses dynamiques pour obtenir du retour sur le comportement d’applications en cours d’exécution, et ce, à des fins de monitorage, de déboggage et d’optimisation. Les languages de programmation et leurs environments d’exécution doivent donc fournir aux développeurs des mécan- ismes qui améliorent l’adaptabilité logicielle.Dans le même temps, l’augmentation de la taille et de la complexité des logi- ciels requièrent des applications faites de nombreux composants développés par différents groupes. Dans ce contexte, soit tous les composant sont supposés dignes de confiance ou bien chaque composant doit être convenablement protégé des autres. Par exemple, un greffon logiciel ne doit pas être capable de manipuler les structures internes ou bien de divulguer les données privée de son application hôte de manière non contrôlée. De la même manière, une bibliothèque malveillante ne doit pas pouvoir corrompre ses clients ou interférer dans leurs opérations. Les lan- guages de programmation doivent donc fournir aux développeurs des mécanismes qui améliorent l’isolation logicielle, tels que l’encapsulation et des politiques de contrôle d’accès sur mesure.Le besoin de supporter des adaptations dynamiques qui peuvent change quasi- ment chaque aspect d’une application d’un côté, et le besoin d’avoir des com- posants convenablement confinés d’un autre côté, poussent la conception des lan- guages de programmation dans deux directions opposées: soit plus de flexibilité, soit plus de contrôle. Cette dissertation étudie cette tension dans le contexte des languages orientée-objet dynamiquement typés via deux mécanismes qui promeu- vent l’adaptabilité logicielle: la réflexion et les méthodes d’extension. Pour cha- cun de ces mécanismes, nous démontrons leur utilité, leurs effets néfastes sur l’encapsulation et proposons des solutions qui conservent leurs forces tout en main- tenant l’encapsulation
Parallel Branch-and-Bound in Multi-core Multi-CPU Multi-GPU Heterogeneous Environments
No full textInternational audienceWe investigate the design of parallel B&B in large scale heterogeneous compute environments where processing units can be composed of a mixture of multiple shared memory cores, multiple distributed CPUs and multiple GPUs devices. We describe two approaches addressing the critical issue of how to map B&B workload with the different levels of parallelism exposed by the target compute platform. We also contribute a throughout large scale experimental study which allows us to derive a comprehensive and fair analysis of the proposed approaches under different system configurations using up to 16 GPUs and up to 512 CPU-cores. Our results shed more light on the main challenges one has to face when tackling B&B algorithms while describing efficient techniques to address them. In particular, we are able to obtain linear speed-ups at moderate scales where adaptive load balancing among the heterogeneous compute resources is shown to have a significant impact on performance. At the largest scales, intra-node parallelism and hybrid decentralized load balancing is shown to have a crucial importance in order to alleviate locking issues among shared memory threads and to scale the distributed resources while optimizing communication costs and minimizing idle time
