13,949 research outputs found
Optimality in Goal-Dependent Analysis of Sharing
We face the problems of correctness, optimality and precision for the static
analysis of logic programs, using the theory of abstract interpretation. We
propose a framework with a denotational, goal-dependent semantics equipped with
two unification operators for forward unification (calling a procedure) and
backward unification (returning from a procedure). The latter is implemented
through a matching operation. Our proposal clarifies and unifies many different
frameworks and ideas on static analysis of logic programming in a single,
formal setting. On the abstract side, we focus on the domain Sharing by Jacobs
and Langen and provide the best correct approximation of all the primitive
semantic operators, namely, projection, renaming, forward and backward
unification. We show that the abstract unification operators are strictly more
precise than those in the literature defined over the same abstract domain. In
some cases, our operators are more precise than those developed for more
complex domains involving linearity and freeness.
To appear in Theory and Practice of Logic Programming (TPLP
Tidal instability in a rotating and differentially heated ellipsoidal shell
The stability of a rotating flow in a triaxial ellipsoidal shell with an
imposed temperature difference between inner and outer boundaries is studied
numerically. We demonstrate that (i) a stable temperature field encourages the
tidal instability, (ii) the tidal instability can grow on a convective flow,
which confirms its relevance to geo- and astrophysical contexts and (iii) its
growth rate decreases when the intensity of convection increases. Simple
scaling laws characterizing the evolution of the heat flux based on a
competition between viscous and thermal boundary layers are derived
analytically and verified numerically. Our results confirm that thermal and
tidal effects have to be simultaneously taken into account when studying
geophysical and astrophysical flows
Sociologie de l’État en recomposition
Dans cet article introductif, King et Le Galès rappellent tout d'abord les enjeux de la sociologie de l'Etat, champ de recherche en recomposition, tout comme l'Etat qu'elle vise à étudier. Ils mentionnent, d'une part, l'importance de l'Etat dans la structuration, la régulation des conflits, les inégalités, le pilotage des sociétés européennes et, d'autre part, les arguments mis en avant dans la littérature qui justifient l'intérêt pour la recomposition de l'état, notamment les processus d'européanisation et de mondialisation. Les auteurs évoquent ensuite brièvement des exemples de chantiers de recherche empiriques contemporains sur l'Etat en soulignant les difficultés de conceptualisation. Ils présentent ensuite une partie des travaux récents de sociologie de l'Etat à partir de deux controverses : la première a pour objet les questions de définition et les variables à prendre en compte pour analyser l'Etat, ce qui recoupe le débat sur la distinction entre Etat fort et Etat faible et la contestation des modèles traditionnels centrés sur l'Europe. La seconde controverse poursuit cette question des variables. Les auteurs, en s'appuyant notamment sur les travaux de Michael Mann, développent l'idée selon laquelle l'analyse des politiques publiques est centrale pour comprendre les recompositions de l'Etat contemporain. La présentation des articles réunis dans ce numéro, organisée autour de ces deux controverses, complète cette introduction. [Résumé éditeur
Case Based Reasoning for Chemical Engineering Design
With current industrial environment (competition, lower profit margin, reduced time to market, decreased product life cycle, environmental constraints, sustainable development, reactivity, innovation…), we must decrease the time for design of new products or processes. While the design activity is marked out by several steps, this article proposed a decision support tool for the preliminary design step. This tool is based on the Case Based Reasoning (CBR) method. This method has demonstrated its effectiveness in other domains (medical, architecture…) and more recently in chemical engineering. This method, coming from Artificial Intelligence, is based on the reusing of earlier experiences to solve new problems. The goal of this article is to show the utility of such method for unit operation (for example) pre-design but also to propose several evolutions for CBR through a domain as complex as the chemical engineering is (because of its interactions, non linearity, intensification problems…). During the pre-design step, some parameters like operating conditions are not precisely known but we have an interval of possible values, worse we only have a partial description of the problem.. To take into account this imprecision in the problem description, the CBR method is coupled with the fuzzy sets theory. After a mere presentation of the CBR method, a practical implementation is described with the choice and the pre-design of packing for separation columns
Experiments on a telluride ore and design of plant for treating same
The ore used in these experiments was a double telluride of gold and silver coming from L Plata, Colorado --page 1
HEAD IMPACT MONITORING: WHAT NEW METHODOLOGIES COULD DO FOR CONCUSSION BIOMECHANICS
Concussion has become a world-wide concern for sports participants. In-vivo head impacts monitoring has long been proposed as a way of identifying and even helping to prevent concussions. Several head impact devices were developed to measure head kinematics on the field, allowing the study of a wide range of sports. However, after fifteen years of data collection and despite a better understanding of injury mechanisms, concussion biomechanics still presents numerous challenges. This study aimed to summarize current knowledge of head impact monitoring via narrative and systematic reviews. The discussion was focused on how technology might have limited previous research, and how innovative analyses approaches might provide new opportunities to further our appreciation of concussion biomechanics
Bilateral Panner’s disease in sickle cell anaemia: Case report
Avascular necrosis is common in sickle cell disease in various vulnerable areas such as in the femoral or humeral heads. Panner’s disease however is described as avascular necrosis of the capitellum, which commonly occurs in a younger age group. It is a pathological process believed to be caused by interference in the blood supply to the growing capitellar epiphysis. A 17 year old boy with sickle cell disease presented with pain on pronation and supination of both elbows, particularly on the lateral side. These movements were restricted in both elbows. Plain radiograph of his elbows showed fragmentation of the capitellum with signs of revascularisation. We have performed a thorough literature search and have not found other reported cases of Panner’s avascular necrosis of the capitellum in association with sickle cell disease. We conclude that Panner’s disease is a possible complication of sickle cell anaemia
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