Delay-based strategy for safety message dissemination in Vehicular Ad hoc NETworks: Slotted or continuous?

International audience—The diversity of applications' types in Vehicular Ad hoc NETworks (VANETs) has spawned a large variety of messages that need to be efficiently disseminated between connected vehicles. The most critical messages are those dedicated for safety applications such as road hazardous warning, signal violation warning, etc. The dissemination of this sort of messages is considered as a challenging task in mobile networks where the topology changes dynamically. Indeed, transmitted messages should achieve a high data reachability within a limited transmission delay and an acceptable overhead in a Vehicle to Vehicle (V2V) communication mode. In this work, we focus on a special type of data dissemination protocols based on the delay strategy. The purpose of this paper is to compare two basic distinguished techniques, namely the slotted technique and the continuous technique, and study in depth their impact on the data dissemination performance. A proper selection of the convenient technique according to the application's requirements is consequently deduced. For a faithful and rigorous study, simulations are performed by means of ns-3 simulator under a realistic VANET environment in terms of map layout, mobility pattern and radio model. Simulation results show that contrary to the theoretical reflection, slotted technique is approved as the most appropriate one for safety message dissemination. This technique achieves the same packet data ratio and redundancy ratio, compared to the continuous one, while reducing the data transmission delay

A Redundancy based Protocol for Safety Message Dissemination in Vehicular Ad Hoc Networks

International audienceThe diversity of applications types in vehicular ad hoc networks (VANETs) has spawned a large variety of messages that need to be disseminated in vehicle to vehicle (V2V) communication mode. The most critical messages are those dedicated for safety applications such as accident warning, road hazardous warning, signal violation warning, etc. The dissemination of this sort of messages is a challenging task in VANETs since they should be efficiently transmitted i.e. by achieving high packet delivery within a certain time limit and an acceptable overhead. In this work, we propose a robust and an original data dissemination protocol called Redundancy-based Protocol (RBP). Contrary to most of the density based protocols, the protocol is beaconless. It takes into account the surrounding vehicle density during the broadcasting process through a specific metric, named “packet redundancy ratio”, calculated locally at each vehicle. Based on this metric, each vehicle is able to dynamically determine the probability of rebroadcast in order to mitigate the broadcast storm problem. The simulation results prove that the proposed protocol outperforms the slotted 1- persistence scheme in terms of packet drop ratio, and network load while still maintaining a low End-to-End delay and high packet reachability. This scheme is suitable for safety applications, as well as for further kinds of application by saving the network capacity consumption

SEAD: A simple and efficient adaptive data dissemination protocol in vehicular ad-hoc networks

International audienceVehicular ad-hoc network (VANET) is becoming a promising technology for improving the efficiency and the safety of intelligent transportation systems by deploying a wide variety of applications. Smart vehicles are expected to continuously exchange a huge amount of data either through safety or non-safety messages dedicated for road safety or infotainment and passenger comfort applications, respectively. One of the main challenges posed by the study of VANET is the data dissemination design by which messages have to be efficiently disseminated in a high vehicular speed, intermittent connectivity, and highly dynamic topology. In particular, broadcast mechanism should guarantee fast and reliable data delivery within a limited wireless bandwidth in order to fit the real time applications’ requirements. In this work, we propose a simple and efficient adaptive data dissemination protocol called “SEAD”. On the one hand, the originality of this work lies in its simplicity and efficiency regardless the application’s type. Simplicity is achieved through a beaconless strategy adopted to take into account the surrounding vehicles’ density. Thanks to a metric locally measured, each vehicle is able to dynamically define an appropriate probability of rebroadcast to mitigate the broadcast storm problem. Efficiency is manifested by reducing excessive retransmitted messages and hence promoting the network capacity and the transmission delay. The simulation results show that the proposed protocol offers very low packet drop ratio and network load while still maintaining a low end-to-end delay and a high packet delivery. On the other hand, SEAD protocol presents a robust data dissemination mechanism which is suitable either for safety applications or for other kinds of application. This mechanism is able to adapt the protocol performance in terms of packet delivery ratio to the application’s requirements

A Redundancy based Protocol for Safety Message Dissemination in Vehicular Ad Hoc Networks

International audienceThe diversity of applications types in vehicular ad hoc networks (VANETs) has spawned a large variety of messages that need to be disseminated in vehicle to vehicle (V2V) communication mode. The most critical messages are those dedicated for safety applications such as accident warning, road hazardous warning, signal violation warning, etc. The dissemination of this sort of messages is a challenging task in VANETs since they should be efficiently transmitted i.e. by achieving high packet delivery within a certain time limit and an acceptable overhead. In this work, we propose a robust and an original data dissemination protocol called Redundancy-based Protocol (RBP). Contrary to most of the density based protocols, the protocol is beaconless. It takes into account the surrounding vehicle density during the broadcasting process through a specific metric, named “packet redundancy ratio”, calculated locally at each vehicle. Based on this metric, each vehicle is able to dynamically determine the probability of rebroadcast in order to mitigate the broadcast storm problem. The simulation results prove that the proposed protocol outperforms the slotted 1- persistence scheme in terms of packet drop ratio, and network load while still maintaining a low End-to-End delay and high packet reachability. This scheme is suitable for safety applications, as well as for further kinds of application by saving the network capacity consumption

Ultrasound cervical length in predicting preterm birth

BackgroundPreterm birth is a leading cause of perinatal morbidity and mortality and represents a major public health problem. It is associated with a 15–20 per cent mortality rate and remains responsible for 75 per cent of perinatal deaths in foetuses without anomalies.AimsThe aim of this study was to evaluate the importance of cervical length measured in the first trimester (11–14 Weeks of amenorrhea “WA”) and the second trimester (20–24 Weeks of amenorrhea” WA”) in an asymptomatic population of singleton pregnancies to assess the risk of spontaneous preterm birth compared to the digital assessment.Methods We conducted a prospective, longitudinal study involving 117 asymptomatic women with singleton pregnancies between January and December 2015.Results In our study, the clinical examination had a low positive predictive value and a low sensibility for screening women at risk of preterm delivery. Cervical length less than 35mm between 12–14WA and 30mm between 22–24WA predicts the occurrence of preterm birth with a high sensitivity (Se), and specificity (Sp).ConclusionWe conclude that ultrasound screening of preterm delivery is now highly recommended

Twin pregnancy with both complete hydatiform mole and coexistent alive fetus: Case report

Twin pregnancy consisting of a complete hydatidiform mole coexisting with a live fetus is a rare condition with an incidence of 1 in 22000 to 1 in 100000 pregnancies. Clinical information is limited and management is difficult due to the risk of pregnancy complications such as fetal death, vaginal bleeding, preeclampsia, hyperthyroidism, and the risk of persistent gestational trophoblastic disease. Thus, the report described about the change of size and implantation site of the molar mass coexisting with a live fetus is rare especially about sonographic findings such as echo patterns. Recently we experienced a case of complete hydatidiform mole with a healthy infant delivered at term

Performance Modeling of SEAD Protocol in Vehicular Environment

International audienceToward the growing number of the transport safety applications offered by VANET, a large amount of messages need to be efficiently disseminated between connected vehicles. The requirement for an efficient data dissemination in vehicular environment is ensuring the highest data reachability, using the minimum network resources within a short end to end delay. To meet these properties, researchers have addressed the data dissemination challenges, mainly the famous broadcast storm, which has lead to a wide variety of solutions. In this work, we present two Simple and Efficient Adaptive data Dissemination protocols called SEAD1 and SEAD2 that combine a probabilis-tic and a delay based approach. The originality of these protocols is that they can be adaptively tuned according to the VANET applications' requirements. Therefore, a rigorous performance evaluation of the protocols is proposed through an analytic model and a large set of NS3 simulations. The analytic results show excellent fits to the simulation results which confirm the accuracy of the proposed model. Moreover , based on our analytic model we became able to thoroughly study the protocols parameters' behavior and derive an accurate configuration. Thereby, a proper trade-off between the packet delivery ratio and the redundancy ratio is possible in attempt to tune the protocols performance according to the application criticality level

Successful pregnancy by IVF in a patient with congenital cervical atresia

Congenital cervical atresia and hypoplasia are rare abnormalities that generally require reconstructive or extirpative procedures to relieve outflow tract obstruction. Infertility is a common sequel, and only four previous pregnancies have been reported. We report a case of successful pregnancy after in-vitro fertilization in a 32-year-old patient with congenital cervical atresia diagnosed at the age of 28 years. She was referred to our unit and had a successful pregnancy after in-vitro fertilization. Caesarean section was performed at 38 weeks gestation. A healthy male baby weighing 3650 g was safely delivered

Auricular mucormycosis complicated by parotid abscess and facial paralysis: A very rare case report

Abstract Mucormycosis is a serious and relatively rare invasive fungal infection. The rhino‐orbito‐cerebral localization is the most frequent. Other localizations have been reported including: cutaneous, pulmonary, disseminated, gastrointestinal, and miscellaneous. Mucormycosis of external ear with facial palsy is extremely rare and only few cases have been reported in the literature. We describe a case of mucormycosis of the external and middle in a 44‐years‐old diabetic patient which had a very aggressive form of necrotic infection of the ear auricle complicated by parotid abscess, facial, and vagal nerve paralysis. Auricular mucormycosis was suspected and the diagnosis was established after biopsy and histological examination. The patient was treated immediately with intravenous amphotericin B followed by extensive surgical debridement of the necrotic lesions. The patient responded well to the treatment despite the persistence of facial palsy