HAL Portal usj Université Saint-Joseph de Beyrouth-Liban
Not a member yet
1220 research outputs found
Sort by
Deep-IRSA: A Deep Reinforcement Learning Approach to Irregular Repetition Slotted ALOHA
No full textInternational audienceThe Internet of Things (IoT) aims to connect billions of devices, most of which are power and memory-constrained. Such constraints require efficient network access. "Irregular Repetition Slotted Aloha'" (IRSA) meets such requirements. In this paper, we optimize IRSA using Deep Reinforcement Learning to obtain Deep-IRSA, and introduce variants that allow re-transmission and user priority classes. We observe the learned degree distribution and throughput, showing that Deep-IRSA performs excellently, is generic, and could well replace known approaches for smaller frame sizes and IRSA variants
Cross-cultural validation of the Arabic version of the Developmental Coordination Disorder Questionnaire DCDQ’07, in a Lebanese sample of children
No full textInternational audienceBackground: The revised version of the Developmental Coordination Disorder Questionnaire (DCDQ'07) is a parent questionnaire designed to identify Developmental Coordination Disorder in 5-15-year-old children.Aim: The aim of this study was to carry out the translation and cross-cultural adaptation of the DCDQ'07, to examine psychometric properties, and to define the cut-off scores of the Arabic-Lebanese version of the questionnaire (DCDQ-AL).Method: 38 parents of children with and without motor difficulties participated in the translation and cross-cultural phase. As for the validation phase and the study of the psychometric properties, a total of one hundred and twenty-four typically developing children (N=124) aged between 5 and 15 years were recruited through schools in different districts across Lebanon, whereas the clinical sample (N = 56) of children with motor difficulties was recruited via psychomotor rehabilitation centers in Beirut and psychomotor therapists working in private clinics across the country. This study used the Movement Assessment Battery for Children - second edition (MABC-2) motor test developed to classify children according to their degree of motor impairment.Results: For test-retest reliability and inter-rater reliability, excellent Intraclass Correlation Coefficients (ICC) were shown with values of 0.94 and 0.9, respectively. The internal consistency value for the DCDQ-AL was high (Cronbach's alpha = 0.947). Correlations between the DCDQ-AL scores and Movement Assessment Battery for Children (MABC-2) show adequate convergent validity (ρ = 0.65, p < .001). Differences in DCDQ-AL scores between children with and without motor difficulties (p < .001) provide clear evidence of discriminative validity. The Lebanese cut-offs are very similar to the Canadian version, except for the 5-7 age band. The DCDQ-AL shows a sensitivity of 0.91 and specificity of 0.77. The adapted questionnaire showed solid psychometric properties, allowing us to conclude that the DCDQ-AL can be used to support a diagnosis of DCD.Conclusion: The results provide evidence that the DCDQ-AL is a valid clinical screening tool for DCD that can assist Arabic speaking professionals in screening children aged 5-15 years old who are at risk of having DCD
POWER MANAGEMENT POLICY FOR LEBANESE TELECOM OPERATORS BASED ON RENEWABLE-ENERGY: A RESPONSE TO THE ECONOMIC CRISIS
No full textInternational audienceThe current economic crisis in Lebanon, which started at the end of 2019, has been exacerbated by the significantdevaluation of the Lebanese pound falling down to previously unseen levels and creating an acute burden onpopulation as well as government institutions. Furthermore, COVID-19 pandemic has reached a peak in 2021forcing the Lebanese government to order several lockdowns and establish online teaching for both scholarinstitutions and universities. This situation has pushed for higher internet data demand, which inevitably led to anincrease in the telecom networks’ power consumption and operating expenditure. In addition, the recent reductionin electrical power production brought a serious concern as for the interruption of telecom services. In this paper,recommendations to design a power-supply management policy for Lebanese internet and mobile carriers inresponse to the aforementioned challenges are proposed. The proposed policy relies on the efficient and optimaluse of renewable-energy (RE), and provides guidelines on Why, Where, What and to Which Extent RE equipmentshould be installed on sites to achieve a solution for an uninterrupted telecom service at the lowest cost possible.Some safety recommendations are also included
A New Arm Voltage Control Scheme for a Single Phase Modular Multilevel Converter
No full textInternational audienceModular Multilevel Converters (MMCs) are widely used in medium to high voltage/power applications such as in energy transformation and grid connected systems. MMCs benefit from being redundant and allowing transformer-less operations. Unfortunately, they suffer from having a high cost due to the high number of sub-modules (SMs). Moreover, they are hard to control. In order to operate the MMCs properly, the load current, the circulating current and the capacitor voltages should be controlled. The usual control methods are synthesized in order to control the average lower and upper arm capacitor voltage as well as the load current. However, in some special cases, the capacitor values could change due to the aging of the capacitors, or the SM may stop working completely. Thus, creating an imbalance in the capacitor voltages of each arm in the system. This paper presents a new control scheme that allows to control the voltage of the upper and lower arms separately while controlling the load current at the same time. The usual and the new proposed controllers are developed and compared through software simulation. Finally, the conclusion is drawn
Calcium Silicate-Based Root Canal Sealers: A Narrative Review and Clinical Perspectives
No full textInternational audienceOver the last two decades, calcium silicate-based materials have grown in popularity. As root canal sealers, these formulations have been extensively investigated and compared with conventional sealers, such as zinc oxide–eugenol and epoxy resin-based sealers, in in vitro studies that showed their promising properties, especially their biocompatibility, antimicrobial properties, and certain bioactivity. However, the consequence of their higher solubility is a matter of debate and still needs to be clarified, because it may affect their long-term sealing ability. Unlike conventional sealers, those sealers are hydraulic, and their setting is conditioned by the presence of humidity. Current evidence reveals that the properties of calcium silicate-based sealers vary depending on their formulation. To date, only a few short-term investigations addressed the clinical outcome of calcium silicate-based root canal sealers. Their use has been showed to be mainly based on practitioners’ clinical habits rather than manufacturers’ recommendations or available evidence. However, their particular behavior implies modifications of the clinical protocol used for conventional sealers. This narrative review aimed to discuss the properties of calcium silicate-based sealers and their clinical implications, and to propose rational indications for these sealers based on the current knowledge
Pentacyclic triterpenes modulate liposome membrane fluidity and permeability depending on membrane cholesterol content
No full textInternational audienceSince the membrane-related processes represent an integral part of the biological activities of drugs, their effect on the membrane dynamics is actually considered. In this study, we investigated the effect of pentacyclic triterpenes (TTPs), oleanolic acid (OA) and erythrodiol (ER), on the fluidity and permeability of liposomes membranes differing by their cholesterol content. All liposomes were prepared by reverse phase evaporation technique (REV). Spin-labeled liposomes exposed or not to TTPs were used for fluidity studies by using 5-and 16-doxyl stearic acids (DSA). TTPs-loaded liposomes (phospholipid:cholesterol of 1:1), and preformed vesicles exposed to TTPs were used for permeability studies by monitoring the release of sulforhodamine B (SRB) at 37˚C. The apparent release constants of SRB were determined by Higuchi model based on a biphasic curve shape (0-10 h; 10-48 h). TTPs-loaded liposomes were characterized for their size and homogeneity. Results showed that ER increased the membrane fluidity at the upper region of the membrane while the both TTPs produced a condensing effect at the deeper region of the membrane. The membrane composition was a critical parameter modulating the effect of TTPs on the membrane permeability. Also, this study consolidated the fact that a fluidizing membrane agent is not necessarily a permeabilizing-membrane compound
Finite element methods for the Darcy-Forchheimer problem coupled with the convection-diffusion-reaction problem
No full textInternational audienceIn this article, we consider the convection-diffusion-reaction problem coupled the Darcy-Forchheimer problem by a non-linear external force depending on the concentration. We establish existence of a solution by using a Galerkin method and we prove uniqueness. We introduce and analyse a numerical scheme based on the finite element method. An optimal a priori error estimate is then derived for each numerical scheme. Numerical investigation are performed to confirm the theoretical accuracy of the discretization
APOE gene variants in primary dyslipidemia
No full textInternational audienceApolipoprotein E (apoE) is a major apolipoprotein involved in lipoprotein metabolism. It is a polymorphic protein and different isoforms are associated with variations in lipid and lipoprotein levels and thus cardiovascular risk. The isoform apoE4 is associated with an increase in LDL-cholesterol levels and thus a higher cardiovascular risk compared to apoE3. Whereas, apoE2 is associated with a mild decrease in LDL-cholesterol levels. In the presence of other risk factors, apoE2 homozygotes could develop type III hyperlipoproteinemia (familial dysbetalipoproteinemia or FD), an atherogenic disorder characterized by an accumulation of remnants of triglyceride-rich lipoproteins. Several rare APOE gene variants were reported in different types of dyslipidemias including FD, familial combined hyperlipidemia (FCH), lipoprotein glomerulopathy and bona fide autosomal dominant hypercholesterolemia (ADH). ADH is characterized by elevated LDL-cholesterol levels leading to coronary heart disease, and due to molecular alterations in three main genes: LDLR, APOB and PCSK9. The identification of the APOE-p.Leu167del variant as the causative molecular element in two different ADH families, paved the way to considering APOE as a candidate gene for ADH. Due to non mendelian interacting factors, common genetic and environmental factors and perhaps epigenetics, clinical presentation of lipid disorders associated with APOE variants often strongly overlap. More studies are needed to determine the spectrum of APOE implication in each of the diseases, notably ADH, in order to improve clinical and genetic diagnosis, prognosis and patient management. The purpose of this review is to comment on these APOE variants and on the molecular and clinical overlaps between dyslipidemias
Identification of a variant in apob gene as a major cause of hypobetalipoproteinemia in lebanese families
No full textInternational audienceFamilial hypobetalipoproteinemia (FHBL) is a codominant genetic disorder characterized by reduced plasma levels of low-density lipoprotein cholesterol and apolipoprotein B. To our knowl-edge, no study on FHBL in Lebanon and the Middle East region has been reported. Therefore, we conducted genetic studies in unrelated families and probands of Lebanese origin presenting with FHBL, in order to identify the causes of this disease. We found that 71% of the recruited probands and their affected relatives were heterozygous for the p.(Arg490Trp) variant in the APOB gene. Haplotype analysis showed that these patients presented the same mutant haplotype. Moreover, there was a decrease in plasma levels of PCSK9 in affected individuals compared to the non-affected and a significant positive correlation between circulating PCSK9 and ApoB levels in all studied probands and their family members. Some of the p.(Arg490Trp) carriers suffered from diabetes, hepatic steatosis or neurological problems. In conclusion, the p.(Arg490Trp) pathogenic variant seems a cause of FHBL in patients from Lebanese origin, accounting for approximately 70% of the probands with FHBL presumably as a result of a founder mutation in Lebanon. This study is crucial to guide the early diagnosis, management and prevention of the associated complications of this disease