Euchi J.,University of Sfax |
Mraihi R.,University of Sousse
Swarm and Evolutionary Computation | Year: 2012
The problem statement tackled in this paper is concentrated on the school bus routing problem (SBRP) in urban areas. This problem is a variant of the vehicle routing problem where we identify three simultaneous decisions that have to be made: determining the set of stops to visit, for each student which stop he should walk to and the latter case occurs when determining the routes visited with the chosen stops, so that the total traveled distance is minimized. Accordingly, to the Tunisian case study and the difficulty to solve it in a manual manner we resort to metaheuristic approaches. We have developed a hybrid evolutionary computation based on an artificial ant colony with a variable neighborhood local search algorithm. Empirically we demonstrate that our algorithm yields consistently better results. © 2011 Elsevier B.V. All rights reserved.
Agency: Cordis | Branch: FP7 | Program: CSA-SA | Phase: REGPOT-2009-2 | Award Amount: 989.00K | Year: 2009
The project foresees the synergic work of participants of various scientific profiles by improvement of scientific relationships, exchange of know-how and experience between the participating centres, including training in MS of Ph.D. students and/or post-doctoral researchers, to upgrade S&T research capacities of centres in MED countries dealing with waste treatment technologies both conventional, advanced and nanoscience based. The proposal includes one SME (Environmental Engineering) in order to give to the project a complementary and applied - business dimension. To be able to participate in the project on an equal-footing basis, the different technological developments of the groups should be balanced by reinforcement of MED countries research infrastructure and improvement of their human potential. This will be achieved by upgrading research equipment in the laboratories of less developed countries and by hiring new senior researchers in these groups. Thus, the transfer and exchange of know-how will be accelerated and the potential of the groups can be better exploited. This approach will prepare laboratories from MED countries to participate more efficiently in European projects. Moreover, it will enable MED countries to increase their contribution in the ERA, making them interesting partners to scientists from MS.
Rhouma D.,University of Monastir |
Romdhane L.B.,University of Sousse
Expert Systems with Applications | Year: 2014
Detecting communities in social networks represents a significant task in understanding the structures and functions of networks. Several methods are developed to detect disjoint partitions. However, in real graphs vertices are often shared between communities, hence the notion of overlap. The study of this case has attracted, recently, an increasing attention and many algorithms have been designed to solve it. In this paper, we propose an overlapping communities detecting algorithm called DOCNet (Detecting overlapping communities in Networks). The main strategy of this algorithm is to find an initial core and add suitable nodes to expand it until a stopping criterion is met. Experimental results on real-world social networks and computer-generated artificial graphs demonstrate that DOCNet is efficient and highly reliable for detecting overlapping groups, compared with four newly known proposals.© 2014 Elsevier Ltd. All rights reserved.
Zardi H.,University of Monastir |
Romdhane L.B.,University of Sousse
Knowledge-Based Systems | Year: 2013
In the study of complex networks, a network is said to have community structure if it divides naturally into groups of nodes with dense connections within groups and only sparser connections between them . Community structures are quite common in real networks. Social networks often include community groups based on common location, interests, occupation, etc. One of the most widely used methods for community detection is modularity maximization . Modularity is a function that measures the quality of a particular division of a network into communities. But in , it is shown that communities that maximize the modularity are certainly groupings of smaller communities that need to be studied. In this work, we define a new function that qualifies a partition. We also present an algorithm that optimizes this function in order to find, within a reasonable time, the partition with the best measure of quality and which does not ignore small community. © 2012 Elsevier B.V. All rights reserved.
Aydi H.,University of Sousse |
Postolache M.,Polytechnic University of Bucharest |
Shatanawi W.,Hashemite University
Computers and Mathematics with Applications | Year: 2012
In this paper, we establish coupled coincidence and common coupled fixed point theorems for (ψ,φ)-weakly contractive mappings in ordered G-metric spaces. Presented theorems extend, generalize and improve many existing results in the literature. An example is given. © 2011 Elsevier Ltd. All rights reserved.
Farhani S.,University of Sousse |
Ozturk I.,Cag University
Environmental Science and Pollution Research | Year: 2015
The aim of this paper is to examine the causal relationship between CO2 emissions, real GDP, energy consumption, financial development, trade openness, and urbanization in Tunisia over the period of 1971–2012. The long-run relationship is investigated by the auto-regressive distributed lag (ARDL) bounds testing approach to cointegration and error correction method (ECM). The results of the analysis reveal a positive sign for the coefficient of financial development, suggesting that the financial development in Tunisia has taken place at the expense of environmental pollution. The Tunisian case also shows a positive monotonic relationship between real GDP and CO2 emissions. This means that the results do not support the validity of environmental Kuznets curve (EKC) hypothesis. In addition, the paper explores causal relationship between the variables by using Granger causality models and it concludes that financial development plays a vital role in the Tunisian economy. © 2015, Springer-Verlag Berlin Heidelberg.
Sebri M.,University of Sousse
Environment, Development and Sustainability | Year: 2014
Although widely studied, the residential water demand remains a controversial issue. The purpose of the current study is to investigate systematic variations across related studies using meta-analysis approach. Particularly, a meta-analytical regression is performed to assess the sensitivity of the price, income and household size elasticities to a number of characteristics including demand specification, data characteristics, price specification, tariff structure, functional form, estimation technique and location of demand. The empirical results of the study reveal that these characteristics have differing influence on the reported elasticities. Obviously, these findings lie in their importance for regulators and policy makers and for academics alike. Among others, two important conclusions emerge. First, water use in summer and winter seasons and water use for indoor and outdoor purposes are found to be important factors affecting the price elasticity. This suggests that peak-load water pricing may be an effective tool for managing water demand. Second, the three elasticities tend to be differently estimated across various regions of the world as well as between developed and developing countries. Therefore, decision makers in a given country would not rely on the findings of studies conducted on other countries in formulating their policies. © 2013 Springer Science+Business Media Dordrecht.
Meddeb A.,University of Sousse
IEEE Communications Magazine | Year: 2016
While time-to-market constraints are accelerating the deployment of a variety of fragmented and proprietary IoT products, there is still a lack of understanding of what an IoT service is meant to be, what its consequences are, and how to promote standard IoT services. This article gives a concise but comprehensive survey of IoT service definition, regulation, and standardization activities. We discuss mainstream standards as well as emerging, independent, and state-funded projects. © 2016 IEEE.
Sebri M.,University of Sousse
Journal of Environmental Planning and Management | Year: 2013
This paper investigates the demand function for residential water in Tunisia, using the discrete/continuous choice model. The analysis uses data for all Tunisian governorates. The main empirical results suggest that water demand is both price and income inelastic, but with high elasticity values (in an absolute sense) estimated for the non-coastal governorates compared to the coastal governorates. Overall, one may argue that combined pricing and non-pricing policies should be implemented in order to save water resources. However, some disparities between Tunisian governorates should be taken into account when applying these policies in order to reach social equity in water consumption. © 2013 Copyright Taylor and Francis Group, LLC.
Haddad M.S.,University of Sousse
Energy Economics | Year: 2011
This paper proposes a simple two-period model that captures the seasonal pattern of water inflows and electricity demand observed in many countries where hydropower is a major source of electricity supply. The model characterizes the effects of different inflows pattern on the optimal water management, capacity, and the associated electricity production and price. The first best capacity is a non-monotonic function of water inflows, which provides a rationale for the observed differences in reservoirs sizes across hydropower systems around the world. The monopoly solution is qualitatively similar to the first best outcome, and the privatization of hydroelectric power generation systems does not always imply a social welfare loss. © 2010 Elsevier B.V.