Construction et maintenance d'une dorsale virtuelle dans les réseaux AD HOC mobiles

Un réseau ad hoc mobile est un réseau complètement distribué ne nécessitant pas d'infrastructure fixe. Les terminaux sont libres de se déplacer n'importe quand et dans n'importe quelle direction. L'absence d'une infrastructure nécessite la collaboration de tous les terminaux pour acheminer le trafic d'une source vers une destination. De nombreux protocoles de routage ont été proposés pour assurer le relayage multi saut, utilisant différentes approches (réactives, proactives et hybrides). Toutefois, les performances de ces protocoles se dégradent en présence de la mobilité. Dans cette thèse, nous proposons d'améliorer la performance des protocoles de routage dans les réseaux ad hoc en construisant une dorsale virtuelle. Une dorsale virtuelle est un sous-ensemble de noeuds sélectionnés de façon à ce que chaque noeud dans le réseau possède au moins un voisin dans la dorsale. L'ensemble des noeuds qui forment la dorsale doit être toujours maintenu connecté même quand les noeuds changent de position. Plus la taille de la dorsale est minimale, plus la maintenance est efficace. Pour construire la dorsale, nous avons proposé un nouvel algorithme basé sur l'approximation de l'ensemble de domination connexe de taille minimale (MCDS). Un réseau ad hoc est généralement modélisé par un graphe à disque unitaire UDG (Unit Disc Graph). Trouver l'ensemble MCDS dans un graphe UDG est un problème NP-Complet. Dans le but de réduire cette complexité, nous avons décomposé le problème en deux étapes: la première étape consiste à déterminer l'ensemble de domination connexe (MDS) au moyen d'une formulation en programmation linéaire et la deuxième étape consiste à trouver l'arbre de recouvrement de l'ensemble MDS et en déduire l'ensemble MCDS. Les résultats de simulations montrent bien que la solution donnée par notre algorithme est très proche de celle fournie par l'analyse théorique. De plus, la taille de la dorsale est nettement inférieure comparée à d'autres algorithmes proposés dans la littérature quand la taille du réseau augmente. Nous avons également proposé une procédure de maintenance distribuée. Cette procédure est basée sur un échange simple des messages de contrôle hello modifiés, ces messages étant utilisés pour la découverte au voisinage. Un noeud qui change de position va alors appliquer cette procédure pour se connecter à la dorsale. Une maintenance locale de la dorsale sera effectuée dans la zone où le noeud va se retrouver dans sa nouvelle position. Les résultats de simulation ont démontré l'efficacité et la fiabilité de cette approche. En effet, plus de 90% des noeuds restent connectés pour une mobilité élevée (vitesse moyenne égale à 30 m/s). De plus, cette procédure est peu sensible au facteur de mise à l'échelle (Scalability). La nature distribuée de la procédure de maintenance s'adapte bien à la dynamique de la structure du réseau engendrée par le mouvement des noeuds. Dans le but de vérifier l'amélioration apportée par la présence d'une dorsale pour les protocoles de routage dans les réseaux ad hoc mobiles, nous avons comparé les performances de certains protocoles de routage, en fonction de la mobilité, en présence de la dorsale avec leurs performances dans leurs versions standards. Les résultats de simulations ont démontré qu'une amélioration de leurs performances peut atteindre 20% pour certains protocoles même pour une mobilité élevée. En conclusion, ce travail de recherche présente de nouvelles solutions pour différents problèmes reliés au routage dans les réseaux ad hoc mobiles

Sexuality after breast cancer: cultural specificities of Tunisian population

Introduction: Women’s sexuality may be particularly affected after breast cancer. The objectives of this study were to evaluate the changes insexual life after treatment of breast cancer in Tunisian women and to identify the influence of demographic and clinical factors on sexuality.Methods: We recruited 50 patients who were in remission for at least 3 months after initial treatment of breast cancer. Sexuality and body imagewere evaluated using the Arabic version of the specific scale of breast cancer QLQ-BR23. Screening for emotional disorders has been done with theArabic version of HAD scale (Hospital anxiety and depression scale). Results: Patients had poor sexual functioning and sexual satisfaction and themean scores were respectively 45.3% and 43.9%. Only menopausal status and sexual difficulties in the partner was significantly related to poorersexual satisfaction (p respectively 0.018 and 0.014). According to the HAD scale, 42% of patients had anxiety and 44% had depression. The sexualsatisfaction was statistically associated with the presence of anxiety symptoms (p=0.0003). Conclusion: Results suggest that the psychologicalside and the sexual difficulties in partner are the most important factors that appear to be involved in sexual satisfaction of Tunisian women afterbreast cancer. So, those factors need to be taken into account in therapeutic process and psychological counseling to maintain and enhancepatient’s psychological well-being

New scheduling algorithm for Uplink LTE system

International audienceIn the LTE (Long Term Evolution) System, packet scheduling is considered the most important step of RRM (Radio Resource Management) to have better resource utilization. In this context, we proposed a new Uplink scheduling scheme for LTE networks and compared its performances with other well known algorithms such as the RME (Recursive Maximum Expansion), the RR (Round Robin) and the BCQI (Best-CQI) Uplink scheduler's algorithms. The RR scheduler is characterized by a high fairness, but low data rates at cell level. On the other hand, the RME scheduler is characterized by its low complexity, but poor fairness. Also, the BCQI scheme is characterized by high data rates, but poor fairness. The main goal of our proposed scheme was to use the Tabu method for to schedule and optimize the allocation of a PRBs (Physical Resource Blocks) efficiently between different users. Simulation results show that the newly proposed scheduling algorithm allows a fair distribution of available LTE resources while keeping an high system's throughput

Neural network approach for component carrier selection in 4G/5G networks

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Antimicrobial resistance genes, virulence markers and prophage sequences in Salmonella enterica serovar Enteritidis isolated in Tunisia using whole genome sequencing

International audienceSalmonella Enteritidis causes a major public health problem in the world. Whole genome sequencing can give us a lot of information not only about the phylogenetic relatedness of these bacteria but also in antimicrobial resistance and virulence gene predictions. In this study, we analyzed the whole genome data of 45 S. Enteritidis isolates recovered in Tunisia from different origins, human, animal, and foodborne samples. Two major lineages (A and B) were detected based on 802 SNPs differences. Among these SNPs, 493 missense SNPs were identified. A total of 349 orthologue genes mutated by one or two missense SNPs were classified in 22 functional groups with the prevalence of carbohydrate transport and metabolism group. A good correlation between genotypic antibiotic resistance profiles and phenotypic analysis were observed. Only resistant isolates carried the respective molecular resistant determinants. The investigation of virulence markers showed the distribution of 11 Salmonella pathogenicity islands (SPI) out of 23 previously described. The SPI-1 and SPI-2 genes encoding type III secretion systems were highly conserved in all isolates except one. In addition, the virulence plasmid genes were present in all isolates except two. We showed the presence of two fimbrial operons sef and ste previously considered to be specific for typhoidal Salmonella. Our collection of S. Enteritidis reveal a diversity among prophage profiles. SNPs analysis showed that missense mutations identified in fimbriae and in SPI-1 and SPI-2 genes were mostly detected in lineage B. In conclusion, WGS is a powerful application to study functional genomic determinants of S. Enteritidis such as antimicrobial resistance genes, virulence markers and prophage sequences. Further studies are needed to predict the impact of the missenses SNPs that can affect the protein functions associated with pathogenicity

Comparison of conventional molecular and whole-genome sequencing methods for subtyping Salmonella enterica serovar Enteritidis strains from Tunisia

International audienceWe sought to determine the relative value of conventional molecular methods and whole-genome sequencing (WGS) for subtyping Salmonella enterica serovar Enteritidis recovered from 2000 to 2015 in Tunisia and to investigate the genetic diversity of this serotype. A total of 175 Salmonella Enteritidis isolates were recovered from human, animal, and foodborne outbreak samples. Pulsed-field gel electrophoresis (PFGE), multiple locus variable-number tandem repeat analysis (MLVA), and wholegenome sequencing were performed. Eight pulsotypes were detected for all isolates with PFGE (DI = 0.518). Forty-five Salmonella Enteritidis isolates were selected for the MLVA and WGS techniques. Eighteen MLVA profiles were identified and classified into two major clusters (DI = 0.889). Core genome multilocus typing (cgMLST) analysis revealed 16 profiles (DI = 0.785). Whole-genome analysis indicated 660 single-nucleotide polymorphism (SNP) divergences dividing these isolates into 43 haplotypes (DI = 0.997). The phylogenetic tree supported the classification of Salmonella Enteritidis isolates into two distinct lineages subdivided into five clades and seven subclades. Pairwise SNP differences between the isolates ranged between 302 and 350. We observed about 311 SNP differences between the two foodborne outbreaks, while only less or equal to 4 SNP differences within each outbreak. SNP-based WGS typing showed an excellent discriminatory power comparing with the conventional methods such as PFGE and MLVA. Besides, we demonstrate the added value of WGS as a complementary subtyping method to discriminate outbreak from non-outbreak isolates belonging to common subtypes. It is important to continue the survey of Salmonella Enteritidis lineages in Tunisia using WGS

Gonadal dysgenesis and the Mayer-Rokitansky-Kuster-Hauser Syndrome in a girl with a 46, XX karyotype: A case report and review of literature

Mayer-Rokitansky-Kuster-Hauser (MRKH) is a characteristic syndrome in which the Mullerian structures are absent or rudimentary. It is also associated with anomalies of the genitourinary and skeletal systems. Its association with gonadal dysgenesis is extremely rare and appears to be fortuitous, independent of chromosomal anomalies. We report such a case in a 21-year-old girl who presented primary amenorrhea and impuberism. The endocrine study revealed hypergonadotrophic hypogonadism. The karyotype was normal, 46, XX. No chromosome Y was detected at the fluorescence in situ hybridization (FISH) analysis. Internal genitalia could not be identified on the pelvic ultrasound and pelvic magnetic resonance imaging. Laparoscopy disclosed concomitant ovarian dysgenesis and MRKH syndrome. There were no other associated malformations. Hormonal substitution therapy with oral conjugated estrogens was begun. The patient has been under regular follow-up for the last two years and is doing well