Towards a smarter directional data aggregation in VANETs

World Wide Web - In the last decade, Vehicular Ad hoc NETworks (VANETs) have attracted researchers, automotive companies and public governments, as a new communication technology to improve the...     

Fatty acid methyl esters (FAME) from oleaginous seeds grown in arid lands. Part II: Ibicella lutea,Onopordum nervosum,Peganum harmala,Smyrnium olusatrum and Solanum elaeagnifolium

The properties of fatty acid methyl esters (FAMEs) obtained from Tunisian oleaginous seeds, grown in arid places with no need of supplementary water, are studied to assess their potential use as biodiesel: devil horn Ibicella lutea, cotton thistle Onopordum nervosum arabicum, Sirian rue Peganum harmala, horse celery Smyrnium olusatrum and silverleaf nightshade Solanum elaeagnifolium. Some key properties such as cloud point, pour point, cold filter plugging point, oxidation stability, cetane number, density, kinematic viscosity, heating value and oxygen extended sooting index have been predicted using equations that correlate the above properties with their ester profiles.     

Use of limestone sands and fillers in concrete without superplasticizer

This paper deals with the effects of the amount of limestone fillers with respect to the rheological, mechanical, and dimensional properties of concretes without superplasticizer. These concretes were made with two limestone coarse aggregates and one limestone sand from the same quarry, in order to avoid any artifact. Five sand containing fillers rate between 1.8% and 24% – representative rates of the categories defined in the EN 12260 norm for aggregates for concretes – were produced by mixture of original sand with its fine fraction or its grained fraction extracted beforehand by washing. The concretes were mix designed with the BetonlabPro2 software, whose algorithms take into account the presence of the limestone fillers. The experimental results show that the concretes containing from 100 to 150 kg/m³ limestone fillers often present optimal properties, with equal consistency. But, higher quantities of fillers do not deteriorate significantly the properties of the concretes, even if their packing density decreases. This behavior is explained not only by the binding effect allotted to the limestone fillers, but also by an improvement of the paste-aggregates bond.     

Facial-expression recognition based on a low-dimensional temporal feature space

Multimedia Tools and Applications - This paper suggests a facial-expression recognition in accordance with face video sequences based on a newly low-dimensional feature space proposed. Indeed, we...     

Study of electromagnetic waves diffraction by bi-dimensional fractal structures using the renormalization method

The analysis of fractal structures by conventional methods gets harder and harder when the number of length scales rises. In this study, we try to combine the renormalization method and the surface impedance model to help rigorous studying of electromagnetic diffraction of fractal structures at their final (infinitum) iteration. As an application, we applied the method to a couple of fractal structures: Cantor Iris 1D and 2D.     

Contribution des fillers calcaires à l’adhérence pâte-granulat. Exemples tunisiens

This article presents compressive test results carried out on a series of hydraulic concrete mixes without admixtures based on Tunisian limestones aggregates. Their estimated strength was calculated with the French model of LCPC (Laboratoire Central des Ponts et Chaussées), which takes into account the effect of bond to the paste and the ceiling effect of the aggregates. To check the experimental values, the parameter of bond had to be associated the content of fillers aggregates, because the performances predicted by the model are lower than the measurements, at least beyond 10% of fillers. The assumption is that the presence of these fine elements, of comparable nature that the aggregates, improves adherence or linking between paste and aggregate, thanks to bringing together the properties of rigidity of the two materials and to a better homogeneity of the system. The relationship found between the calcareous filler ratio and the bond coefficient then makes it possible to extend the forecasts of the model to the hydraulic mixtures containing aggregates crushed limestones, naturally rich in fillers.      

Formal concept analysis based user model for distributed systems

User profile has contributed to customize user access and adjusts applications to its needs. In this respect, automatically building of user profiles issue is an important research area. Nevertheless, standardizing these profiles in terms of representation and acquisition schemes, more especially in large scale systems like Peer-to-Peer systems (P2P), is a complex task. In this paper, we introduce a distributed user profile modelling approach based on user search topics history without the need of any external knowledge resource (e.g., ontology). This model learns from past interests to guess correlations between user requests, associated topics, relevant documents and nodes (i.e., peers) to enhance any information retrieval process. The solution is based on an extension of Formal Concept Analysis (FCA) theory. We also study, the integration of our model in query routing (i.e., content discovery) and results aggregation processes for P2P systems. Carried out experiments, performed under a P2P simulator environment, showed that our model outperforms its competitors in terms of effectiveness and efficiency.     

MPC: A RSUs deployment strategy for VANET

A Vehicle AdHoc Network is mainly composed of mobile vehicles and fixed Road Site Units (RSUs). The latter is usually very expensive to deploy and has a crucial role in maintaining the network connectivity. Therefore, the design of an efficient RSU deployment strategy that enables a high coverage ratio and a lower deployment cost has been of paramount importance. In this respect, we introduce in this paper a new spatiotemporal coverage strategy for nonsafety Vehicle AdHoc Network applications like driving assistance and business promotion, called Minimal Mobility Patterns Coverage (MPC). The main thrust of MPC is to (1) depict the mobility patterns of moving vehicles from their trace files and then (2) compute the adequate RSU locations in order to cover the extracted mobility patterns by the minimal possible number of RSUs. To this end, we firstly provide a new method to depict the mobility patterns of vehicles by mining the correlations between the kept track connections of vehicle trajectories versus crossed junctions. Secondly, we introduce a new way to compute the adequate RSU locations through the instantiation of the well‐known problem of extracting minimal transversals of a hypergraph. Experimental results show that our RSUs deployment strategy performs better than baseline strategies.