Domain knowledge specification for energy tuning

To overcome the challenges of energy consumption of HPC systems, the European Union Horizon 2020 READEX (Runtime Exploitation of Application Dynamism for Energy-efficient Exascale computing) project uses an online auto-tuning approach to improve energy efficiency of HPC applications. The READEX methodology pre-computes optimal system configurations at design-time, such as the CPU frequency, for instances of program regions and switches at runtime to the configuration given in the tuning model when the region is executed. READEX goes beyond previous approaches by exploiting dynamic changes of a region's characteristics by leveraging region and characteristic specific system configurations. While the tool suite supports an automatic approach, specifying domain knowledge such as the structure and characteristics of the application and application tuning parameters can significantly help to create a more refined tuning model. This paper presents the means available for an application expert to provide domain knowledge and presents tuning results for some benchmarks.Web of Science316art. no. E465

Flowering plants preferred by native wild bees (hymenoptera, apoidea, apiformes) in the Algerian Littoral Region

This study considered the plant floral resources visited by native wild and honey bees in Algiers (northern Algeria). Three botanical families accounted for almost 2/3 of all visits: Asteraceae (44.1%), Boraginaceae (15.3%) and Brassicaceae (13%). Plants in other families were visitedless frequently (e.g.Ranunculaceae (0.1%)). At the species level, the most frequently visited plant was Anchusa azurea (Boraginaceae), reaching 15.2% of the total bee  visitation. Our work showed that Apis mellifera Linnaeus, 1758 is, typically, a polylectic species and that the majority of solitary bees exhibited the more specialised trait of oligolectics. The narrowest trophic niche varied between 0.01 and 0.06 bits for Halictus rufipes (Fabricius, 1793), Halictus scabiosae (Rossi, 1790) (Halictidae), Osmia pinguis Pérez, 1895 and Osmia tricornis Linnaeus, 1811  (Megachilidae).Key-words: Wild bees, floral choices, natural habitat, northern of Algeria

Study of genitalia morphometric variability of the two Species Helix aperta and Helix aspersa (gasteropoda, pulmonata)

Our research aims for, firstly, the study of genitalia morphometric variability of the two species Helix aperta and Helix aspersa, and the relation of this variability with individual’s weight and shell size. Secondly, differences in dimensions of the genital organs between the two studied species were investigated. This study showed, first, the existence of an important dimensional variability of genital organs in both studied species, then, a positive correlation between organs’ measurements and those of weight and shell. Finally, two genital organs, that are flagellum and proximal duct of bursa copulatrix, proved to be interesting to discriminate between the two species Helix aperta and Helix aspersa, because both organs are greater in Helix aspersa.Key-words: Genitalia, Helix aperta, Helix aspersa, morphometric variability, positive correlation, weight, shell size, discriminating characters

Study of trophic relationships between diaspididae family species -host plants -predators and parasitoids in Algeria

The use of parasitoids and predators in biocontrol contribute to the development of sustainable agriculture, respects environment and human health. In this context, we undertook the identification of natural Diaspididae enemies located on the Algerian territory. Results highlight three predatory families: Coccinellidae, Nitidulidae and Coniopterygidae families, the first represented by the most voracious species as Rhyzobius lophantae living on 19 Diaspines observed on 121 plants, from the northern, and two parasitoid families lived on 39 Diaspididae species affecting 125 plants and were represented by four genera and 23 species such as Aphytis and Encarcia (Aphelinidae) lived on 31 diaspididae species found on 125 host plants. The most voracious and polyphagous species identified are interesting for IPM.Keywords: Diaspididae, Predators, Parasitoids, Host-plant, Algeri

Généralisation de l’analyse de performance décrémentale vers l’analyse différentielle

A crucial step in the process of application performance analysis is the accurate detection of program bottlenecks. A bottleneck is any event which contributes to extend the execution time. Determining their cause is important for application developpers as it enable them to detect code design and generation flaws.Bottleneck detection is becoming a difficult art. Techniques such as event counts,which succeeded to find bottlenecks easily in the past, became less efficient because of the increasing complexity of modern micro-processors, and because of the introduction of parallelism at several levels. Consequently, a real need for new analysis approaches is present in order to face these challenges.Our work focuses on performance analysis and bottleneck detection of computeintensive loops in scientific applications. We work on Decan, a performance analysis and bottleneck detection tool, which offers an interesting and promising approach called Decremental Analysis. The tool, which operates at binary level, is based on the idea of performing controlled modifications on the instructions of a loop, and comparing the new version (called variant) to the original one. The goal is to assess the cost of specific events, and thus the existence or not of bottlenecks.Our first contribution, consists of extending Decan with new variants that we designed, tested and validated. Based on these variants, we developed analysis methods which we used to characterize hot loops and find their bottlenecks. Welater, integrated the tool into a performance analysis methodology (Pamda) which coordinates several analysis tools in order to achieve a more efficient application performance analysis.Second, we introduce several improvements on the Decan tool. Techniquesdeveloped to preserve the control flow of the modified programs, allowed to use thetool on real applications instead of extracted kernels. Support for parallel programs(thread and process based) was also added. Finally, our tool primarily relying on execution time as the main concern for its analysis process, we study the opportunity of also using other hardware generated events, through a study of their stability, precision and overheadUne des étapes les plus cruciales dans le processus d’analyse des performances d’une application est la détection des goulets d’étranglement. Un goulet étant tout évènement qui contribue à l’allongement temps d’exécution, la détection de ses causes est importante pour les développeurs d’applications afin de comprendre les défauts de conception et de génération de code. Cependant, la détection de goulets devient un art difficile. Dans le passé, des techniques qui reposaient sur le comptage du nombre d’évènements, arrivaient facilement à trouver les goulets. Maintenant, la complexité accrue des micro-architectures modernes et l’introduction de plusieurs niveaux de parallélisme ont rendu ces techniques beaucoup moins efficaces. Par conséquent, il y a un réel besoin de réflexion sur de nouvelles approches.Notre travail porte sur le développement d’outils d’évaluation de performance des boucles de calculs issues d’applications scientifiques. Nous travaillons sur Decan, un outil d’analyse de performance qui présente une approche intéressante et prometteuse appelée l’Analyse Décrémentale. Decan repose sur l’idée d’effectuer des changements contrôlés sur les boucles du programme et de comparer la version obtenue (appelée variante) avec la version originale, permettant ainsi de détecter la présence ou pas de goulets d’étranglement.Tout d’abord, nous avons enrichi Decan avec de nouvelles variantes, que nous avons conçues, testées et validées. Ces variantes sont, par la suite, intégrées dans une analyse de performance poussée appelée l’Analyse Différentielle. Nous avons intégré l’outil et l’analyse dans une méthodologie d’analyse de performance plus globale appelée Pamda.Nous décrirons aussi les différents apports à l’outil Decan. Sont particulièrement détaillées les techniques de préservation des structures de contrôle du programme,ainsi que l’ajout du support pour les programmes parallèles.Finalement, nous effectuons une étude statistique qui permet de vérifier la possibilité d’utiliser des compteurs d’évènements, autres que le temps d’exécution, comme métriques de comparaison entre les variantes Deca

Using two-dimensional graphene lenses to increase the effectiveness of solar panels

We aim to enhance the efficiency of solar panels by covering them with graphene lenses that collect and concentrate light rays onto the panels. The simulation was performed using the Monte Carlo method and provided precise results regarding the improvement of solar panel performance. The simulation showed a substantial increase in the intensity of electrical current at critical densities of the graphene lenses used, suggesting the need for further research to enhance the utilization of renewable energy sources, even in regions with limited sun exposure and varying weather conditions

Domain Knowledge Specification for Energy Tuning

The European Horizon 2020 project READEX is developing a tool suite for dynamic energy tuning of HPC applications. While the tool suite supports an automatic approach, domain knowledge can significantly help in the analysis and the runtime tuning phase. This paper presents the means available in READEX for the application expert to provide his expert knowledge to the tool suite

Andrena (Hymenoptera: Apoidea: Andrenidae) fauna of Western Algeria, with a preliminary assessment of their pollen preferences

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