43 research outputs found

    Scalable and Cost Efficient Algorithms for Virtual CDN Migration

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    Virtual Content Delivery Network (vCDN) migration is necessary to optimize the use of resources and improve the performance of the overall SDN/NFV-based CDN function in terms of network operator cost reduction and high streaming quality. It requires intelligent and enticed joint SDN/NFV migration algorithms due to the evident huge amount of traffic to be delivered to end customers of the network. In this paper, two approaches for finding the optimal and near optimal path placement(s) and vCDN migration(s) are proposed (OPAC and HPAC). Moreover, several scenarios are considered to quantify the OPAC and HPAC behaviors and to compare their efficiency in terms of migration cost, migration time, vCDN replication number, and other cost factors. Then, they are implemented and evaluated under different network scales. Finally, the proposed algorithms are integrated in an SDN/NFV framework. Index Terms: vCDN; SDN/NFV Optimization; Migration Algorithms; Scalability Algorithms.Comment: 9 pages, 11 figures, 4 tableaux, conference Local Computer Networks (LCN), class

    Comparative Study of Different Active Control Systems of High Rise Buildings under Seismic Excitation

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    Large number of active vibration control systems existing in the literature has brought lot of confusion for engineers and junior researchers. This study deals with the comparison of different active control systems of a 20-storey building under seismic excitation for three control devices: Active Mass Damper (AMD), Active Bracing System (ABS) and Connected Building Control (CBC). Two different control configurations are considered to add active damping to the building. The first one employs force actuator and displacement sensor and is examined with first and second order Positive Position Feedback, Lead compensators and Direct Velocity Feedback. The second configuration employs a displacement actuator collocated with a force sensor and an Integral Force Feedback control law. A total number of 15 control cases are compared from the point of view of stability, robustness, performance and control effort

    Pulmonary Barotrauma Including Huge Pulmonary Interstitial Emphysema in an Adult with Status Asthmaticus: Diagnostic and Therapeutic Challenges

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    Introduction: Pulmonary interstitial emphysema is a rare finding defined as abnormal air collection inside the lung interstitial tissues. Described more frequently in ventilated new-borns, pulmonary interstitial emphysema is an uncommon barotrauma-related complication in adults. Management and clinical sequelae are poorly described. Patient: We describe the case of a 64-year-old man who presented with huge pulmonary interstitial emphysema together with simultaneous pulmonary barotrauma in status asthmaticus requiring invasive ventilation. Discussion: There are no guidelines for the management of such complications and their possible sequelae but conservative treatment seems to be effective. The treatment of our patient is described

    Cerebral Vasculitis Complicating Pneumococcal Meningitis

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    Introduction: Cerebral vasculitis is an uncommon life-threatening complication of community-acquired bacterial meningitis. Patient and methods: We report the case of a 64-year-old woman with pneumococcal meningitis who developed parainfectious vasculitis causing ischaemic brain damage. Cerebral magnetic resonance imaging (MRI) confirmed the diagnosis. Clinical and radiological recovery after delayed addition of corticosteroid was achieved. Discussion: This report shows that the onset of neurological deficits following pneumococcal meningitis can be caused by cerebral vasculitis. Underdosing with antibiotics and delayed adjunctive dexamethasone seem to favour this complication. There are no guidelines for treatment but high doses of steroids led to resolution in this case

    Regularized multiframe super-resolution image reconstruction using linear and nonlinear filters

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    The primary goal of the multiframe super-resolution image reconstruction is to produce an image with a higher resolution by integrating information extracted from a set of corresponding images with low resolution, which is used in various fields. However, super-resolution image reconstruction approaches are typically affected by annoying restorative artifacts, including blurring, noise, and staircasing effect. Accordingly, it is always difficult to balance between smoothness and edge preservation. In this paper, we intend to enhance the efficiency of multiframe super-resolution image reconstruction in order to optimize both analysis and human interpretation processes by improving the pictorial information and enhancing the automatic machine perception. As a result, we propose new approaches that firstly rely on estimating the initial high-resolution image through preprocessing of the reference low-resolution image based on median, mean, Lucy-Richardson, and Wiener filters. )is preprocessing stage is used to overcome the degradation present in the reference low-resolution image, which is a suitable kernel for producing the initial high-resolution image to be used in the reconstruction phase of the final image. then, L2 norm is employed for the data-fidelity term to minimize the residual among the predicted high-resolution image and the observed low-resolution images. Finally, bilateral total variation prior model is utilized to restrict the minimization function to a stable state of the generated HR image. )e experimental results of the synthetic data indicate that the proposed approaches have enhanced efficiency visually and quantitatively compared to other existing approaches

    Assessment of urban green space dynamics influencing the surface urban heat stress using advanced geospatial techniques

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    Urban areas are mostly heterogeneous due to settlements and vegetation including forests, water bodies and many other land use and land cover (LULC) classes. Due to the overwhelming population pressure, urbanization, industrial works and transportation systems, urban areas have been suffering from a deficiency of green spaces, which leads to an increase in the variation of temperature in urban areas. This study investigates the conceptual framework design towards urban green space (UGS) and thermal variability over Kolkata and Howrah city using advanced remote sensing (RS) and geospatial methods. The low green space is located in the highly built-up area, which is influenced by thermal variations. Therefore, the heat stress index showed a high area located within the central, north, northwestern and some parts of the southern areas. The vegetated areas decreased by 8.62% during the ten years studied and the other land uses increased by 11.23%. The relationship between land surface temperature (LST) and the normalized difference vegetation index (NDVI) showed significant changes with R2 values between 0.48 (2010) and 0.23 (2020), respectively. The correlation among the LST and the normalized difference built-up index (NDBI) showed a notable level of change with R2 values between 0.38 (2010) and 0.61 (2020), respectively. The results are expected to contribute significantly towards urban development and planning, policymaking and support for key stakeholders responsible for the sustainable urban planning procedures and processes

    Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

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    Contains fulltext : 172380.pdf (publisher's version ) (Open Access

    Utilisation de technologies d'édition du génome afin de générer des cardiomyocytes matures à partir de cellules souches pluripotentes humaines induites

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    Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a very promising model for several scientific and therapeutic applications ranging from disease modeling to drug discovery, and from predictive toxicology to regenerative medicine. Despite numerous efforts, current protocols do not yet lead to a maturation phenotype equivalent to adult human myocardium. Indeed, key features of hiPSC-CMs remaining closer to fetal stages of development, such as gene expression, electrophysiology and function. Transcriptome analysis performed at Sanofi have confirmed these findings at the genome-wide level. Indeed, KCNJ2 and CASQ2 which are implicated in the two major physiological characteristics of cardiac cells, their electrophysiological behavior and calcium handling, respectively, were expressed at very low levels in hiPSC-CMs in comparison with adult cardiomyocytes. This thesis aimed to improve the maturation of hiPSC-CMs by using genome editing technologies. We generated stable hiPSC-CMs with inducible expression of KCNJ2, or CASQ2 or both genes (KCNJ2-CASQ2 hiPSC-CMs) and studied their functional and electrophysiological phenotype by several complementary methods. Upon doxycycline induction of KCNJ2 and CASQ2, KCNJ2-CASQ2 hiPSC-CMs displayed phenotypic benefits expected from previous studies of each maturation gene, including a drastic reduction of spontaneous beating, hyperpolarized resting membrane potential, shortened action potential duration and enhanced calcium transients. In addition, co-expression of the two genes enhanced Na+ spike slope of extracellular field potential and Ca2+ handling. We tested four reference drugs and observed signatures of known cardiac effects in KCNJ2-CASQ2 hiPSC-CMs, including arrhythmias induced by QT prolonging drug (E-4031), which were more easily detected than in control hiPSC-CMs. Therefore, KCNJ2-CASQ2 hiPSC-CMs exhibited a more mature phenotype than hiPSC-CMs and such genetically engineered hiPSC-CMs could be useful for testing cardiac toxicity of novel candidate drugs.Les cardiomyocytes dérivés des cellules souches pluripotentes humaines induites (hiPSC-CMs) représentent des modèles in vitro prometteurs pour plusieurs applications scientifiques et thérapeutiques allant de la modélisation de pathologies à la découverte de médicaments et de la toxicologie prédictive à la médecine régénérative. Malgré les nombreux progrès dans ce domaine, les protocoles de différenciation actuels ne permettent pas d’atteindre le stade de maturité que l’on retrouve chez le myocarde adulte de l’Homme. En effet, certaines caractéristiques majeures des hiPSC-CMs demeurent similaires à celles de cardiomyocytes fœtaux telles que l’expression de plusieurs gènes cardiaques, l’électrophysiologie ou leur fonction contractile. En effet, des analyses transcriptomiques réalisés au sein de notre laboratoire à Sanofi ont révélé que les gènes KCNJ2 et CASQ2, impliqués respectivement dans l’électrophysiologie et la gestion du calcium, étaient sous-exprimés dans les hiPSC-CMs en comparaison aux cardiomyocytes adultes. Cette thèse avait pour objectif d’améliorer la maturation des hiPSC-CMs en utilisant des technologies d’édition du génome. Ainsi, nous avons généré des lignées stables de hiPSC-CMs qui expriment de manière inductible KCNJ2 ou CASQ2 ou les deux gènes simultanément puis nous avons examiné leurs phénotypes fonctionnels et électrophysiologiques par le biais de méthodes d’analyses complémentaires. A la suite à l’induction de l’expression de KCNJ2 et CASQ2 par la doxycycline, les hiPSC-CMs montraient des bénéfices phénotypiques tels que la diminution drastique de la fréquence des battements spontanés, une hyperpolarisation du potentiel de repos membranaire, la diminution de la durée du potentiel d’action et l’amélioration du flux de calcium transitoire. En plus de ces bénéfices attendus, l’expression concomitante de ces deux gènes a amélioré la pente de la pointe du potentiel de champ extracellulaire associée au courant sodique ainsi que la gestion du calcium. Nous avons ensuite évalué le bénéfice de l’expression de ces transgènes sur la toxicologie prédictive en testant des molécules agonistes ou antagonistes de canaux ioniques utilisées classiquement dans le cadre des essais précliniques de toxicité cardiaque. Nous avons notamment observé plus d’arythmies induites par l’E4031 avec les hiPSC-CMs exprimant conjointement KCNJ2 et CASQ2 par rapport aux cardiomyocytes contrôles. Ainsi, les hiPSC-CMs exprimant simultanément KCNJ2 et CASQ2 présentent un phénotype plus mature que les hiPSC-CMs natifs et de tels cardiomyocytes édités génétiquement peuvent être utiles pour l’évaluation de la toxicité cardiaque de nouveaux médicaments candidats

    L'acoustoélasticité dans les solides isotropes et son expérimentation

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    Doctorat en sciences appliquées -- UCL, 199
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