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2012Wassim Ayadi, ,
BiMine+: An efficient algorithm for discovering relevant biclusters of DNA microarray data
Knowl. Based Syst. 35: 224-234, 2012
Abstract
Biclustering is a very useful tool for analyzing microarray data. It aims to identify maximal groups of genes which are coherent with maximal groups of conditions. In this paper, we propose a biclustering algorithm, called BiMine+, which is able to detect significant biclusters from gene expression data. The proposed algorithm is based on two original features. First, BiMine+ is based on the use of a new tree structure, called Modified Bicluster Enumeration Tree (MBET), on which biclusters are represented by the profile shapes of genes. Second, BiMine+ uses a pruning rule to avoid both trivial biclusters and combinatorial explosion of the search tree. The performance of BiMine+ is assessed on both synthetic and real DNA microarray datasets. Experimental results show that BiMine+ competes favorably with several state-of-the-art biclustering algorithms and is able to extract functionally enriched and biologically relevant biclusters.
Wassim Ayadi, ,Evolutionary Biclustering Algorithm of Gene Expression Data
DEXA Workshops 2012: 206-210, 2012
Abstract
Microarrays represent a new technology for measuring expression levels of several genes under various biological conditions generating multiple data. These data can be analyzed by using biclustering method which aims to extract a maximum number of genes and conditions presenting a similar behavior. This paper proposes a new evolutionary approach to obtain maximal high-quality biclusters of highly-correlated genes. The performance of the proposed algorithm is assessed on synthetic gene expression data. Experimental results show that our algorithm competes favorably with several state-of-the-art biclustering algorithms.
Ameni Azzouz, Meriem Ennigrou, Boutheina JLIFI,Combining tabu search and genetic algorithm in a multi-agent system for solving flexible job shop problem
n International Conference on Enterprise Information Systems (Vol. 3, pp. 47-53), 2012
Abstract
The Flexible Job Shop problem (FJSP) is an important extension of the classical job shop scheduling problem, in that each operation can be processed by a set of resources and has a processing time depending on the resource used. The objective is to minimize the make span, i.e., the time needed to complete all the jobs. This works aims to propose a new promising approach using multi-agent systems in order to solve the FJSP. Our model combines a local optimization approach based on Tabu Search (TS) meta-heuristic and a global optimization approach based on genetic algorithm (GA).
Meriam Jemel, Nadia Ben Azzouna,Towards a scalable and dynamic access control system for web services
In Proceedings of the 8th International conference on Web Information Systems and Technologies(WEBIST 2012), April 18 -21 2012,Porto, Portugal, pages 161-166, 2012., 2012
Abstract
Web services are vulnerable to different types of security attacks. The problem of secure access to web-based
applications is becoming increasingly complex. Management complexity arises because of the scalability
considerations such as the large number of web services users and their invocations and the fact that the
access control system should take into account the context. In this paper we describe the architecture of
our TDRBAC (Trust and Dynamic Role Based Access Control) model which is implemented using agent
technology. In fact, this technology fulfills several requirements of web service’s access control by providing
both context awareness and scalability. In order to verify the scalability of the proposed solution, we expose
some experimental results from a prototype implemented using JADE (Java Agent DEvelopment) platform.
The performance tests show that our TDRBAC multi-agent based system meets the scaling requirements of
large distributed services.Kalthoum Rezgui, Hédia Sellemi,Competency Models: A Review of Initiatives
-, 2012
Abstract
For some years, competency-based learning and training has known a growing interest, especially in conjunction with proliferation of the terms « knowledge society », « citizen mobility », or « globalization ». Competency modeling becomes an important concept in many domains, especially in human resource development and e-Learning. In this paper, we present a review of relevant competency metadata standards and some ontology-based approaches for competency modeling.
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2011Sami Rojbi,
User modeling and Web-based customazation techniques: An examination of the published literature
2011 4th International Conference on Logistics, 2011
Abstract
This paper proposes a state of the art of the user modeling and interfaces customization techniques. It presents and discusses techniques intended to be used by application’s designers and also end-user based techniques. It specifies the characteristics modeled in these systems as well as the used technologies.
Wassim Ayadi,Biclustering of microarray data
Algorithms in Computational Molecular Biology: Techniques, Approaches and Applications, John Wiley & Sons, Inc., 2011
Abstract
Biclustering of microarray data
, Lamjed Ben Said,Greedy local improvement of SPEA2 algorithm to solve the multiobjective capacitated transshipment problem
In: Coello, C.A.C. (eds) Learning and Intelligent Optimization. LION 2011. Lecture Notes in Computer Science, vol 6683. Springer, Berlin, Heidelberg., 2011
Abstract
We consider a multi-location inventory system where inventory choices at each location are centrally coordinated through the use of lateral Transshipments. This cooperation between different locations of the same echelon level often leads to cost reduction and service level improvement. However, when some locations face embarrassing storage capacity limits, inventory sharing through transshipment may cause undesirable lead time. In this paper, we propose a more realistic multiobjective transshipment model which optimizes three conflicting objectives: (1) minimizing the aggregate cost, (2) maximizing the fill rate and (3) minimizing the transshipment lead time, in the presence of different storage capacity constraints. We improve the performance of the well-known evolutionary multiobjective algorithm SPEA2 by adequately applying a multiobjective quasi-gradient local search to some candidate solutions that have lower density estimation. The resulting hybrid evolutionary algorithm outperforms NSGA-II and the original SPEA2 in both spread and convergence. It is also shown that lateral transshipments constitute an efficient inventory repairing mechanism in a wide range of system configurations.
Ines Thabet, , ,A Multi-agent Organizational Model for Grid Scheduling
KES-AMSTA 2011: 148-158, 2011
Abstract
Multi-agent technology provides high level organizational concepts (groups, roles, commitments, interaction protocols) to structure, coordinate and ease the adaptation of distributed systems efficiently. This paper proposes to model a grid scheduling system as a multi-agent system organization. The resulting organizational model, based on the Agent Group Role meta-model of Ferber, is evaluated at the conceptual and implementation level. At the conceptual level, we evaluate the efficiency, robustness and flexibility of our model. At the implementation level, the analysis and the evaluation of our proposition, done through simulations, show its efficiency.
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2010Wassim Ayadi, ,
Iterated Local Search for Biclustering of Microarray Data
Pattern Recognition in Bioinformatics. PRIB 2010. Lecture Notes in Computer Science, vol 6282, pp 219–229, 2010
Abstract
In the context of microarray data analysis, biclustering aims to identify simultaneously a group of genes that are highly correlated across a group of experimental conditions. This paper presents a Biclustering Iterative Local Search (BILS) algorithm to the problem of biclustering of microarray data. The proposed algorithm is highlighted by the use of some original features including a new evaluation function, a dedicated neighborhood relation and a tailored perturbation strategy. The BILS algorithm is assessed on the well-known yeast cell-cycle dataset and compared with two most popular algorithms.
