Vers une plateforme holistique de protection de la vie privée dans les services géodépendants

Les services géodépendants (LBS : Location-Based Services) sont présents dans la plupart de nos activités quotidiennes, ils représentent l’ensemble des services en ligne qui fournissent des informations basées sur la géolocalisation des individus. On peut les retrouver dans plusieurs domaines tels que les soins médicaux, le divertissement, le transport, et de nombreuses autres activités. En outre, avec leur présence dans presque toutes les tâches quotidiennes, leur utilité ne peut être négligée, ainsi que leur impact sur la façon dont les données des individus sont traitées n’est plus la même. De plus, avec la croissance du nombre de propriétaires de dispositifs mobiles, il est devenu plus facile de localiser un individu, rendant ainsi presque inévitables les problèmes liés à la confidentialité. Par conséquent, des solutions plus sévères sont fortement nécessaires afin de gérer les problèmes de confidentialité et de conserver l’utilité de LBS. Nous présentons dans cette thèse une recherche qui porte sur la protection de la vie privée des utilisateurs dans un LBS tout en gardant un maximum d’utilité des services. Autre que l’état de l’art et les fondements théoriques, ce travail est divisé en trois parties principales, chacune d’elles décrit un ensemble des composants connexes de la plateforme proposée, nommée Deloc. En conclusion, nous proposons une plateforme collaborative de protection de la confidentialité des utilisateurs LBS, qui est à la fois efficace, performante, et qui surtout n’affecte pas l’utilité estimée de l’utilisation d’un LBS donné.Location-Based Services (LBS) are present in most of our daily activities, and they repre sent all online services used to provide information based on the location of individuals. These services can be found in several fields such as healthcare, entertainment, transportation, and many other daily activities. Besides, along with their presence in almost all daily tasks, their utility cannot be ignored, and as a result, their impact on how individuals’ data are processed is no longer the same. With smartphone ownership growth, it has become easier to locate an individual, and privacy issues have become almost inescapable. Hence, more severe solutions are strongly required to handle privacy issues while keeping the utility of LBS. We present in this thesis a research work about protecting the privacy of users in an LBS while keeping maximum utility of the service. In addition to the state of the art and the theoretical background, this work is divided into three main parts when each one describes a set of related components of the proposed framework, called Deloc. We present in this thesis a research into about privacy protection in LBSs while maintaining the maximum utility of these services. In addition to the state of the art and the theoretical background, this work is divided into three main parts, where each one describes a set of related components of the proposed framework named Deloc. • Delegation concept. We propose in this part the main concept behind this re search. The goal is to propose a collaborative mechanism where each user participates in the protection of other users without the need for transforming his geographical coordinates, nor losing the utility of the service. We also evaluate the concept on data issued from real-world users in a finely simulated environment with tuneable parameters, and we demonstrate its high guarantees of privacy, efficiency, and utility facing most of the current LBS applications. • Quantification of risks and trust. This part is based on the fact that the dependence of delegation concept on the LBS users may imply privacy issues. This part of the paper discusses two models of quantification and measurement of risks and trust in the context of LBS. First, we propose a model based on the theory of mutual information that is used to assess the risks associated with the use of the delegation concept. Then we discuss a model based on Markov chains that helps to estimate the level of trust for each of the collaborators. We also discuss the applicability of both models and their theoretical and empirical validation. • Privacy Metric for Collaborative Systems. The lack of a metric designed for collaborative systems is the main motivation behind this part. We discuss our proposal for a privacy metric based on the theory of fuzzy sets. We propose three models that each one of them deals with a subset of Delocprivacy requirements. The attacker, the privacy, and the utility model are the three models used to define the privacy metric named d-fuzziness. We also discuss the validation of the metric, and its measurement efficiency in the case of collaborative mechanisms, especially Deloc. In conclusion, we propose a collaborative location privacy-preserving framework, which is at the same time efficient, powerful, and which does not affect the estimated utility of using LBSs

The Effects of Bilingualism and Language Attitudes on Algerian Students’ Academic Proficiency in Medical Sciences

This study examines learners’ Cognitive Academic Language Proficiency and Basic Interpersonal Communicative Skills in L2 in order to determine the accuracy level of French oral language proficiency and academic achievement of students in Medical sciences (Tlemcen University). Adopting a few sociolinguistic research tools, the researcher has obtained some results confirming that students often lag behind in academic performance due to the delay in the development of Cognitive Academic Language Proficiency (CALP) and to the complexity of bilingual language acquisition despite their apparent language fluency which reflects their achievement in Basic Interpersonal Communication Skills interpreted as communicative success. Another important aim in this research was to analyze the effects of students’ attitudes towards French

STR-based genetic structure of the Berber population of Bejaia (Northern Algeria) and its relationships to various ethnic groups

Patterns of genetic variation in human populations have been described for decades. However, North Africa has received little attention and Algeria, in particular, is poorly studied, Here we genotyped a Berber-speaking population from Algeria using 15 short tandem repeat (STR) loci D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA from the commercially available AmpF/STR Identifiler kit. Altogether 150 unrelated North Algerian individuals were sampled across 10 administrative regions or towns from the Bejaia Wilaya (administrative district). We found that all of the STR loci met Hardy-Weinberg equilibrium expectations, after Bonferroni correction and that the Berber-speaking population of Bejaia presented a high level of observed heterozygosity for the 15 STR system (>0.7). Genetic parameters of forensic interest such as combined power of discrimination (PD) and combined probability of exclusion (PE) showed values higher than 0.999, suggesting that this set of STRs can be used for forensic studies. Our results were also compared to those published for 42 other human populations analyzed with the same set. We found that the Bejaia sample clustered with several North African populations but that some geographically close populations, including the Berber-speaking Mozabite from Algeria were closer to Near-Eastern populations. While we were able to detect some genetic structure among samples, we found that it was not correlated to language (Berber-speaking versus Arab-speaking) or to geography (east versus west). In other words, no significant genetic differences were found between the Berber-speaking and the Arab-speaking populations of North Africa. The genetic closeness of European, North African and Near-Eastern populations suggest that North Africa should be integrated in models aiming at reconstructing the demographic history of Europe. Similarly, the genetic proximity with sub-Saharan Africa is a reminder of the links that connect all African regions.Instituto Gulbenkian de Ciência, Laboratoire d'Excellence (LABEX) entitled TULIP: (ANR-10-LABX-41)

A cytogenetic and pollen study of annual Medicago species from Soummam Valley (Northeastern of Algeria)

This paper reports a cytogenetic study of eight Medicago L. species sampled from the Soummam Valley (northeastern Algeria). Chromosome numbers and meiosis irregularities during microsporogenesis were explored. Pollen viability rate and pollen size were also examined. The studied taxa are diploid and display bivalent pairing and regular chromosome segregation during meiosis. Although meiosis appears regular, some anomalies were detected in relatively high cumulated rates (14.66%–26.14%). The most common meiotic abnormality examined here is related to cytomixis (from 14.66% in M. littoralis to 25.83% in M. laciniata). Other anomalies were also etected, including chromatic bridges, asynchronous divisions, micronuclei and multipolar cells. Consequently, the species exhibited varying ercentages of pollen viability (from 70.11% in M. laciniata to 99.14% in M. littoralis). Pollen viability was negatively correlated with meiotic abnormalities (Pearson correlation coefficient R = −0.72, p = 0.043). The pollen grains were also heterogeneous in size. Medicago truncatula Gaertn. and M. laciniata (L.) Miller presented the most variable pollen size (relative standard deviation exceeding 19%). Medicago littoralis is distinguished from other species by possessing homogeneous and large sized pollen (relative standard deviation RSD = 6.73 %). The cytogenetic and pollen data provided by this study are discussed in the context of species systematics and in the perspective of genetic improvement

Synthèse et propriétés physicochimiques d’oxydes de structure Spinelle

Les oxydes NiFe2-xCuxO4 (0 ≤ x ≤ 0.5), de type spinelle ont été préparés par la méthode sol-gel pour déterminer l'effet de la substitution de fer par le cuivre sur les propriétés de l'oxyde. Les résultats de l'analyse thermique thermogravimétrique et différentielle(ATG/ATD) indiquent que la décomposition du précurseur à l'oxyde s'est terminée à 880°C. Les composés étudiés montrent une phase spinelle pure dans la gamme de température de calcination à (600-1000°C) et la solubilité du cuivre dans la structure NiFe2O4 était limitée à x =0,4. L'analyse par spectroscopie IR montre que les échantillons présentent deux modes de vibration actifs observés à 602 et 408 cm-1 sont les liaisons M-O aux sites tétraédriques et octaédriques de la structure spinelle.Les images MEB montrent l'agglomération des particules de différentes formes et tailles . L'étude de la réaction de dégagement d'oxygène (OER) sur chaque catalyseur oxyde dans 1 M KOH ,indiquent clairement que la meilleure électroactivité vers l'OER peut être obtenue avec l'électrode NiFe2O

A Novel Small Molecule Targeting Oncogenic miR-10b in Gastric Cancer

https://openworks.mdanderson.org/sumexp21/1206/thumbnail.jp

Breaking seed coat dormancy of six tree species

Breaking physical dormancy in some forest seeds is a challenge for scientists and forest managers to obtain an homogeneous germination for larger seed samples. The role played by the seed coat in seed dormancy of six trees with great interest in agroforestry (Robinia pseudoacacia, Leucaena leucocephala, Erythrostemon gilliesii, Styphnolobium japonicum, Acacia dealbata and Brachychiton populneus) was tested by the effects of the pretreatment and its duration on the performance of seed germination, by considering the final germination percentage (FGP) and the mean germination time (MGT). These parameters are estimated at various times of incubation (5, 10 and 15 days) in Petri dishes and stored in darkness at (25 ± 2°C). The pretreatment consists of an immersion of seeds in concentrated sulphuric acid during 30, 60 and 90 minutes. Sowing without pretreatment (control) revealed no germination induction for B. populneus and A. dealbata, except for R. pseudoacacia, L. leucocephala and S. japonica where the germination does not exceed 12% for all the experience duration. Generally, pretreatments were very useful to improve seed germination. The time of immersion into sulphuric acid significantly affected (P < 0.0001) the FGP and the MGT in all studied species. A duration of 30 minutes of soaking was adequate to give a very high rate of germination for L. leucocephala, E. gilliesii, S. japonica and A. dealbata with respective FGP of 100%, 95%, 100% and 100%. However, an extended duration of pretreatment of 60 minutes was necessary for a maximal germination for R. pseudoacacia and B. populneus with FGP of 85% and 100%, respectively. A prolonged duration of 90 minutes of presowing was very fatal for L. leucocephala, A. dealbata and B. populneus. An excellent germinative strength is characterized by a higher FGP and a reduced MGT

Mechanism and Kinetic Parameters of the Thermal Decomposition of Gibbsite Al(OH) 3 by Thermogravimetric Analysis

In this study, the mechanism and the kinetic parameters of the thermal decomposition of gibbsite Al(OH)3 were studied by differential thermogravimetry technique under non-isothermal conditions, between room temperature and 1200 K at heating rates of 5, 10, 15 and 20 The obtained differential thermogravimetry curves show clearly three distinct peaks. The first peak is due to the partial dehydroxylation of gibbsite. Among the 32 types of differential equations of non-isothermal kinetics, we have found that the most suitable mechanism is (A 3/2 : 2/3 ) also called Avrami-Erofeev equation of order 2/3. The values of the activation energy EA and of the pre-exponential factor K are 157 kJ mol −1 and 7.58 × 10 15 s −1 , respectively. The second peak corresponds to the decomposition of gibbsite to boehmite. Decomposition is controlled by the rate of second-order reaction (F2: g(x) = (1 − x) −1 − 1), under the applied conditions. The activation energy EA and pre-exponential factor K correspond to 243 kJ mol −1 and 3.73 × 10 22 s −1 , respectively. The third peak is due to transformation of boehmite to alumina. However the mechanism for such transformation is better described by the 3/2 rate order reaction (F 3/2 : g(x) = (1 − x) −1/2 − 1). In addition, the values of EA and K were determined to be around 296 kJ mol −1 and 1.82 × 10 19 s −1 , respectively. The results of differential thermogravimetry were supplemented by the differential thermal analysis. X-ray powder diffraction analysis was carried out for samples of gibbsite treated at different temperatures between 200 and 1200 • C in 200 • C steps