A survey on pseudonym changing strategies for Vehicular Ad-Hoc Networks

The initial phase of the deployment of Vehicular Ad-Hoc Networks (VANETs) has begun and many research challenges still need to be addressed. Location privacy continues to be in the top of these challenges. Indeed, both of academia and industry agreed to apply the pseudonym changing approach as a solution to protect the location privacy of VANETs'users. However, due to the pseudonyms linking attack, a simple changing of pseudonym shown to be inefficient to provide the required protection. For this reason, many pseudonym changing strategies have been suggested to provide an effective pseudonym changing. Unfortunately, the development of an effective pseudonym changing strategy for VANETs is still an open issue. In this paper, we present a comprehensive survey and classification of pseudonym changing strategies. We then discuss and compare them with respect to some relevant criteria. Finally, we highlight some current researches, and open issues and give some future directions

THE INTEGRATION OF WEB 2.0 TOOLS IN ENGLISH LANGUAGE TEACHING

The present study aims at investigating the integration of Web 2.0 tools among EFL high school teachers in English language teaching. To evaluate the state of art in the Moroccan context; both, quantitative and qualitative data is collected with the help of a questionnaire and an interview administered to forty seven high school teachers in Fes city. The results of the study revealed that the integration of Web 2.0 tools in English language teaching is still in its infancy stage since only 12,77 % of the whole sample make use of Web 2.0 tools in their teaching practices; especially, YouTube, and Facebook. This study also shows that the use of Web 2.0 tools among teacher is limited either to providing online resources for students or as teaching aids in classrooms. The low percentage of high school teachers who use Web 2.0 tools in their teaching practices is attributed to the challenges that hinder the integration of Web 2.0 tools in English language teaching. This is so, because 93,62% of teachers state that there are certain challenges that hinder the integration of Web 2.0 tools in English language teaching. These challenges according to the respondents are categorized into the lack of knowledge in using Web 2.0 tools in teaching, the lack of digital materials in classrooms, and their negative attitudes toward the integration of Web 2.0 tools in educational purposes. Based on the findings of this study some pedagogical implications are directed to EFL teachers, and educational policy makers.  Article visualizations

HPDM: A Hybrid Pseudonym Distribution Method for Vehicular Ad-hoc Networks

AbstractProtecting the location privacy of drivers is still one of the main challenges in Vehicular Ad-hoc Networks (VANETs). The changing of pseudonym is commonly accepted as a solution to this problem. The pseudonyms represent fake vehicle identifiers. Roadside Units (RSUs) play a central role in the existing pseudonyms distribution solutions. Indeed, the VANET area should totally be covered by RSUs in order to satisfy the demand of vehicles in terms of pseudonyms. However, the total coverage is costly and hard to be achieved, especially in the first phase of VANETs deployment. In addition, RSUs could be overloaded due to the large number of pseudonyms requests that could be received from vehicles. In this paper, we propose a new hybrid pseudonyms distribution method, called HPDM that relies not only on RSUs but also on vehicles to perform the pseudonyms distribution. The analysis demonstrate that HPDM is privacy and accountability preserving. The performance evaluation of the proposed method is carried out using veins framework based on OMNet++ network simulator and SUMO mobility engine and shows its feasibility

dSDiVN: a distributed Software-Defined Networking architecture for Infrastructure-less Vehicular Networks

In the last few years, the emerging network architecture paradigm of Software-Defined Networking (SDN), has become one of the most important technology to manage large scale networks such as Vehicular Ad-hoc Networks (VANETs). Recently, several works have shown interest in the use of SDN paradigm in VANETs. SDN brings flexibility, scalability and management facility to current VANETs. However, almost all of proposed Software-Defined VANET (SDVN) architectures are infrastructure-based. This paper will focus on how to enable SDN in infrastructure-less vehicular environments. For this aim, we propose a novel distributed SDN-based architecture for uncovered infrastructure-less vehicular scenarios. It is a scalable cluster-based architecture with distributed mobile controllers and a reliable fall back recovery mechanism based on self-organized clustering and failure anticipation.Comment: 12 pages, 5 figures, accepted in I4CS201

Primjena umjetne neuronske mreže i regresije potpornih vektora u modeliranju kvantitativnog odnosa strukture-svojstva i topljivosti otopljenih čvrstih tvari u superkritičnom CO2

In this study, the solubility of 145 solid solutes in supercritical CO2 (scCO2) was correlated using computational intelligence techniques based on Quantitative Structure-Property Relationship (QSPR) models. A database of 3637 solubility values has been collected from previously published papers. Dragon software was used to calculate molecular descriptors of 145 solid systems. The genetic algorithm (GA) was implemented to optimise the subset of the significantly contributed descriptors. The overall average absolute relative deviation MAARD of about 1.345 % between experimental and calculated values by support vector regress SVR-QSPR model was obtained to predict the solubility of 145 solid solutes in supercritical CO2, which is better than that obtained using ANN-QSPR model of 2.772 %. The results show that the developed SVR-QSPR model is more accurate and can be used as an alternative powerful modelling tool for QSAR studies of the solubility of solid solutes in supercritical carbon dioxide (scCO2). The accuracy of the proposed model was evaluated using statistical analysis by comparing the results with other models reported in the literature. This work is licensed under a Creative Commons Attribution 4.0 International License.U ovom je istraživanju korelirana topljivost 145 čvrstih otopljenih tvari u superkritičnom CO2 (scCO2) primjenom tehnika računalne inteligencije zasnovanim na modelima kvantitativne strukture i svojstva (QSPR). Baza podataka 3637 topljivosti prikupljena je iz prethodno objavljenih radova. Program Dragon primijenjen je za izračunavanje molekularnih deskriptora 145 čvrstih sustava. Genetski algoritam (GA) implementiran je kako bi se optimizirao podskup deskriptora sa značajnim doprinosom. Ukupno prosječno apsolutno relativno odstupanje MAARD od oko 1,345 % između eksperimentalnih i izračunatih vrijednosti pomoću regresije potpornih vektora modelom SVR-QSPR dobiveno je za predviđanje topljivosti 145 čvrstih otopljenih tvari u superkritičnom CO2, što je bolje od onog dobivenog primjenom modela ANN-QSPR (2,772 %). Rezultati pokazuju da je razvijeni model SVR-QSPR precizniji i da se može primijeniti kao alternativni alat za modeliranje QSAR studija topljivosti otopljenih čvrstih tvari u superkritičnom ugljikovu dioksidu (scCO2). Točnost predloženog modela procijenjena je statističkom analizom uspoređivanjem rezultata s ostalim modelima zabilježenim u literaturi. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Clustered chain founded on ant colony optimization energy efficient routing scheme for under-water wireless sensor networks

One challenge in under-water wireless sensor networks (UWSN) is to find ways to improve the life duration of networks, since it is difficult to replace or recharge batteries in sensors by the solar energy. Thus, designing an energy-efficient protocol remains as a critical task. Many cluster-based routing protocols have been suggested with the goal of reducing overall energy consumption through data aggregation and balancing energy through cluster-head rotation. However, the majority of current protocols are concerned with load balancing within each cluster. In this paper we propose a clustered chain-based energy efficient routing algorithm called CCRA that can combine fuzzy c-means (FCM) and ant colony optimization (ACO) create and manage the data transmission in the network. Our analysis and results of simulations show a better energy management in the network

Alloimmunisation foeto-maternelle Rhésus grave à propos d’un cas et revue de la littérature

L’incompatibilité foeto-maternelle Rhésus peut être à l’origine d’un syndrome hémolytique dont l’expression clinique est l´anémie foetale éventuellement compliquée par une anasarque foeto-placentaire ou à l’extrême une mort foetale in utéro. Nous rapportons l’observation d’un cas d’allo immunisation Rhésus à 34 SA ayant aboutit un hydrops foetalis, l’extraction foetale par césarienne en vue d’une exsanguino-transfusion a été réalisée, mais le nouveau né est décédé au cours de l’exsanguino-transfusion. Le dépistage des femmes à risque et l’utilisation d’Immunoglobulines anti D ont permis une réduction importante de l´incidence des accidents d’incompatibilité. La mesure du pic systolique de vélocité dans l’artère cérébrale moyenne a bouleversé la surveillance et la prise en charge prénatale des anémies foetales secondaires à une allo-immunisation Rhésus. Son utilisation dans la surveillance des cas d’allo-immunisation Rhésus permettrait ainsi de réserver les procédures invasives (cordocentèse) comme geste thérapeutique qui permet la transfusion foetale in utéro. Grâce à une collaboration multidisciplinaire cohérente, l’extraction foetale peut être programmée, ce qui permet une prise en charge adéquate et rigoureuse, même des nouveaux nés avec atteinte sévère.Pan African Medical Journal 2015; 2

Caesarean scar endometriosis: a case report

Endometriosis is a common disorder in women of reproductive age but is rarely observed in abdominal scar after caesarean section. The authors report a case of 35-year-old woman referred for a painful lump at caesarean scar. Preoperative diagnosis of caesarean scar endometriosis was made on the basis of clinical examination and radiological imaging and confirmed histologically after large surgical excision of the mass. Increasing awareness of this rare entity among clinicians can help in early diagnosis and appropriate treatment

Giant placental chorioangioma discovered at 29 weeks’ gestation: a case report

Chorioangiomas are the commonest non-trophoblastic tumors of placenta with an estimated incidence of 1%. The majority of them are small, asymptomatic and only found by careful pathologic examination of the placenta. Occasionally, they can attain a large diameter (≥ 4-5cm) resulting in what is termed ‘giant chorioangioma’ with a high feto-maternal morbidity and mortality rates. We report a case of giant chorioangioma discovered accidentally during a routine obstetric ultrasound. Expectant management was adopted. Ultrasound follow-up revealed several fetal complications; an elective caesarean section was made giving birth to a premature new-born with enormous hepatosplenomegaly, died on the first day of life. Diagnosis and management of chorioangioma represents a stringent challenge for obstetricians due to its potentially serious antenatal complications