Adaptive vectorial lifting concept for convolutive blind source separation

This paper describes a new multi-resolution approach for the blind separation of convolutive image mixtures in transform domain. The proposed method uses an Adaptive Vectorial case of Quincunx Lifting Scheme (AVQLS), based on wavelet decomposition, and a geometric unmixing algorithm. It proceeds in three steps: first, the mixed images are decomposed by AVQLS. Then, the unmixing algorithm is applied to the more relevant component to get a transformed estimate of the original images. An inverse transform is, thereafter, applied to obtain an estimate of the original images. Experiments carried out on medical images showed that the proposed method yields better separation results than many widely used blind source separation algorithms.     

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.     

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...     

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.     

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...     

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.     

Current Approaches for Solving Over-Constrained Problems

We summarize existing approaches to model and solve overconstrained problems. These problems are usually formulated as combinatorial optimization problems, and different specific and generic formalisms are discussed, including the special case of multi-objective optimization. Regarding solving methods, both systematic and local search approaches are considered. Finally we review a number of case studies on overconstrained problems taken from the specialized literature.     

Résistance à la traction et module d’élasticité des bétons calcaires: application à des mélanges tunisiens

This article presents the results of the tensile strength and the elastic modulus obtained between one day and a year on a vast set of mortars, micro-concretes and concretes carried out with limestone aggregates out coming from five Tunisian careers. For the tensile strength, the results were compared with the compression strength measured on the same mixtures. The obtained evolutions do not coincide with the power-laws generally adopted for the predicted tensile strength. An approach, where the law parameters (coefficient, exponent) can be adjusted, gives better results. The resort to another more precise model, described by a hyperbolic law, makes it possible to provide a physical interpretation to the tensile strength behavior of the hydraulic mixtures. Its parameters are linked to the aggregate strength and cohesion in the paste-aggregate transition zone. For the elastic modulus, the use of a model taking into account the properties of the granular phase and the binding phase made it possible to reach the elastic modulus of the aggregates.