Simulation directe 2D et 3D de la dispersion d'agglomérats sous cisaillement dans une matrice polymère

Nous avons développé une méthode de simulation directe de la dispersion de charges sphériques dans une matrice polymère soumise à un cisaillement. L'agglomérat est immergé dans un fluide newtonien et incompressible. Il est considéré comme un assemblage de sphères liées entre elles par une énergie de cohésion, modélisée par une viscosité de cohésion. Les paramètres de ce modèle sont la contrainte hydrodynamique et la longueur caractéristique de la zone d'influence des sphères. Ce modèle simple permet une première approche du phénomène de dispersion dans un écoulement de cisaillement. Les tendances observées lors des simulations menées en 2D et 3D montrent qu'une augmentation du taux de cisaillement entraîne une érosion plus rapide de la charge

Modeling the Egyptian Path to Energy Efficiency towards 2035

This paper offers a tool to evaluate the implementation of energy efficiency actions for the residential sector with a focus on Egypt which adopted a path to achieve 8.6 Mtoe energy savings through 2035. The Country has been divided in climate zones and users classified according to the kind of their typical household in the cities and in the rural areas. The National Energy Efficiency Plan (NEEP) has been taken as a reference, technologies' improvement has been evaluated in terms of savings and costs and a plan from 2017 through 2035 has been detailed by the means of an easy-to-use optimization model. The novelty lies in offering this model a tool allowing an analysis where to spot possible bottlenecks but also hidden potentials in the targeted users, among which photovoltaic for residential applications

A Content-oriented Web Cache Policy

The increasing popularity of network-based multimedia applications poses many challenges for multimedia content providers to supply efficient and scalable multimedia services. Peer-to-Peer (P2P) networks have been shown to be a promising approach to provide large scale video services over Internet since these networks increase scalability and robustness. In this paper, we propose and analyze an object management policy approach for videos web cache in a P2P context, taking advantage of object's meta-data, e.g video popularity, and object's encoding techniques, e.g Scalable Video Coding (SVC). We carry out trace-driven simulation so as to evaluate the performance of our approach and compare it against traditional object management policy approaches. The experiment results show that our proposed approach can improve the performance of the cache substantially. © 2009 IEEE.Institute of Electrical and Electronics Engineers,Communications SocietyYoutube website, , http://www.youtube.comDailymotion website, , www.dailymotion.comPodlipnig, S., Böszörmenyi, L., A survey of web cache replacement strategies (2003) ACM Comput. Surv, 35 (4), pp. 374-398Wang, J., A survey of web caching schemes for the internet (1999) SIGCOMM Comput. Commun. Rev, 29 (5), pp. 36-46F. Benevenuto, F. Duarte, V. Almeida, and J. Almeida, Web cache replacement policies: properties, limitations and implications, in Web Congress, 2005. LA-WEB 2005. Third Latin American, Oct.-2 Nov. 2005, pp. 8 pp.-Michael Zink, Y.G., Suh, K., Kurose, J., Watch Global Cache Local: YouTube Network Traces at a Campus Network - Measurements and Implications (2008) IEEE MMCNCha, M., Kwak, H., Rodriguez, P., Ahn, Y.-Y., Moon, S., I Tube, You Tube, Everybody Tubes: Analyzing the World's Largest User Generated Content Video System (2007) ACM Internet Measurement Conference, , OctoberBalakrishnan, H., Kaashoek, M.F., Karger, D., Morris, R., Stoica, I., Looking up data in p2p systems (2003) Commun. ACM, 46 (2), pp. 43-48http://www.skype.comNadjib Achir, K.S., Pujolle, G., Object-based Unequal loss protection for Multi-Object Video Delivery (2003) 4th EURASIP Conference focused on Video/Image Processing and Multimedia Communications, , Jul

Accurate gingival recession quantification using 3D digital dental models

Objectives: To develop and validate a method for accurate quantitative assessment of gingival recessions based on superimposition of serial 3D digital models. Materials and methods: Gingival recessions of mild (0.5–2 mm) and increased (3–7 mm) severity were simulated on stone casts and surface models were created. The outlines of the gingival margins of the mild (A) and severe recessions (B) were compared to the original gingival margins following 3D best fit superimposition through a gold standard technique (GS), which used intact adjacent structures, and the tested method (CC), which used single tooth crowns at the position of recessions, as superimposition reference. The primary outcome was the distance between the most apical point of each corresponding gingival margin along the respective tooth long axis. Results: For mild recessions, the median difference of the test methods (CC_A) from the reference method (GS_A) was 0.008 mm (IQR: 0.093; range: − 0.143, 0.147). For severe recessions, the median difference of the test method (CC_B) from the reference method (GS_B) was 0.009 mm (IQR: 0.091; range: − 0.170, 0.198). The proposed method (CC) showed very high intra- and inter-operator reproducibility (median: 0.025 and 0.033 mm, respectively). Conclusions: The suggested method offers highly accurate monitoring of gingival margin changes and diagnosis of gingival recessions using 3D digital dental models. The method is applicable irrespective of changes in tooth position or form, allowing for assessments over any time span. Clinical relevance: The accurate detection and visualization of gingival margin changes in 3D will enhance diagnosis and patient-doctor communication. © 2022, The Author(s)

Initial Approach Toward Self-configuration and Self-optimization in IP Networks

The growing heterogeneity and scalability of Internet services has complicated, beyond human capabilities, the management of network devices. Therefore, a new paradigm called autonomic networking is being introduced to control, in an efficient and automatic manner, this complex environment. This approach aims to enhance network elements with capabilities that allow them to choose their own behavior for achieving high-level directives. This so called autonomic network element should be able to optimize its configuration, ensure its protection, detect/repair unpredicted conflicts between services requirements and coordinate its behavior with other network elements. In this paper, we present a research activity that investigates this new concept, and applies it to facilitate the configuration and the optimization of a multi-services IP network. This approach is a first step toward building a self-configured and self-optimized IP network that automatically supports the QoS requirements of heterogeneous applications without any external intervention. Different paradigms have been explored in order to model this behavior and to render network equipment autonomic. A laboratory prototype has been developed to highlight the autonomic behavior of the network to achieve heterogeneous QoS requirements of multimedia and data applications

A Content-Oriented Web Cache Policy under P2P Video Distribution Systems

International audienceThe increasing popularity of network-based multimedia applications poses many challenges for content providers to supply efficient and scalable services. Peer-to-peer (P2P) systems have been shown to be a promising approach to provide large-scale video services over the Internet since, by nature, these systems show high scalability and robustness. In this paper, we propose and analyze an object management policy approach for video web cache in a P2P context, taking advantage of object's metadata, for example, video popularity, and object's encoding techniques, for example, scalable video coding (SVC). We carry out trace-driven simulations so as to evaluate the performance of our approach and compare it against traditional object management policy approaches. In addition, we study as well the impact of churn on our approach and on other object management policies that implement different caching strategies. A YouTube video collection which records over 1.6 million video's log was used in our experimental studies. The experiment results have showed that our proposed approach can improve the performance of the cache substantially. Moreover, we have found that neither the simply enlargement of peers' storage capacity nor a zero replicating strategy is effective actions to improve performance of an object management policy