Mohamed Wahbi

Mohamed Wahbi
University College Cork | UCC · Insight Centre for Data Analytics

Post-doctoral research

About

25
Publications
1,733
Reads
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100
Citations
Introduction
Mohamed Wahbi is currently Post-doctoral research at University College Cork, Republic of Ireland. He started his Ph.D. in 2009. He received his Ph.D. in July 2012 from LIRMM, University Montpellier 2, France and LIMIARF, Mohammed V University-Agdal, Morocco. His researchs focused on Distributed Constraint Reasoning. The title of his thesis is: ``Algorithms and Ordering Heuristics for Distributed Constraint Satisfaction Problems’’.
Additional affiliations
October 2013 - present
University College Cork
Position
  • Post-doctoral research
September 2012 - August 2013
IMT Atlantique
Position
  • Professor (Assistant)
Description
  • Maître-assistant associé
September 2011 - August 2012
French National Centre for Scientific Research
Position
  • Professor (Assistant)
Description
  • Attaché temporaire d'enseignement et de recherche
Education
July 2009 - July 2012
October 2008 - July 2012
Mohammed V University of Rabat
Field of study
  • Computer Science
September 2006 - July 2008
Mohammed V University of Rabat
Field of study
  • Computer Science

Publications

Publications (25)
Article
Distributed constraint satisfaction problems (DisCSPs) can express decision problems where physically distributed agents control different decision variables, but must coordinate with each other to agree on a global solution. Asynchronous Backtracking (ABT) is a pivotal search procedure for DisCSPs. ABT requires a static total ordering on the agent...
Conference Paper
The geographically distributed data centres problem (GDDC) is a naturally distributed resource allocation problem. The problem involves allocating a set of virtual machines (VM) amongst the data centres (DC) in each time period of an operating horizon. The goal is to optimize the allocation of workload across a set of DCs such that the energy cost...
Conference Paper
Reordering agents during search is an essential component of the efficiency of solving a distributed constraint satisfaction problem. Termination values have been recently proposed as a way to simulate the min-domain dynamic variable ordering heuristic. The use of termination values allows the greatest flexibility in reordering agents dynamically w...
Conference Paper
Full-text available
The expressiveness of Distributed CSP has been recently enhanced to include global constraints. Careful reformulation of contractible global constraints has been shown to improve efficiency. In this paper, we first show that explained global constraints further improves the efficiency in distributed problems , sometimes by over two orders of magnit...
Conference Paper
Full-text available
Distributed constraint satisfaction (DisCSP) models decision problems where physically distributed agents control different decision variables, but must communicate with each other to agree on a global solution. Most DisCSP research assumes an abstract communication layer based on a peer-to-peer wired network. However, many practical applications o...
Conference Paper
Full-text available
The Distributed Constraint Optimization Problem (DCOP) is a powerful framework for modeling and solving applications in multi-agent coordination. Asynchronous Forward Bounding (AFB BJ) is one of the best algorithms to solve DCOPs. We propose AFB BJ + , a revisited version of AFB BJ in which we refine the lower bound computations. We also propose to...
Article
Full-text available
We propose two new algorithms for solving Distributed Constraint Satisfaction Problems (DisCSPs). The first algorithm, AFC-ng, is a nogood-based version of Asynchronous Forward Checking (AFC). Besides its use of nogoods as justification of value removals, AFC-ng allows simultaneous backtracks going from different agents to different destinations. T...
Chapter
This chapter provides the state of the art in the area of distributed constraint reasoning. The chapter gives preliminary definitions of the distributed constraint satisfaction problem (DisCSP) framework. A DisCSP is composed of a group of autonomous agents, where each agent has control of some elements of information about the whole problem, i.e....
Chapter
This chapter provides the state of the art in the area of centralized constraint programming. It defines the constraint satisfaction problem (CSP) formalism and presents some academic and real examples of problems modeled and solved by centralized CSP. These examples range from academic problems to real-world applications. Then, the chapter overvie...
Chapter
Nogood-based asynchronous forward checking (AFC-ng) is an efficient and robust algorithm for solving distributed constraint satisfaction problems (DisCSPs). AFC-ng performs an asynchronous forward-checking (FC) phase during synchronous search. This chapter proposes two synchronous search algorithms based on the same mechanism as AFC-ng. However, in...
Chapter
This chapter introduces a synchronous algorithm for solving distributed constraint satisfaction problems (DisCSPs). This algorithm is a nogood-based version of asynchronous forward checking (AFC). Hence, it is called nogood-based asynchronous forward checking (AFC-ng). Besides its use of nogoods as justification of value removal, AFC-ng allows simu...
Chapter
This chapter proposes Agile asynchronous backtracking (Agile-ABT) for solving distributed constraint satisfaction problems (DisCSPs), an asynchronous dynamic ordering algorithm that does not follow the standard restrictions in ABT algorithms. The order of agents appearing before the agent receiving a backtrack message can be changed with a great fr...
Chapter
This chapter proposes a corrigendum of the protocol designed for establishing the priority between orders in the asynchronous backtracking algorithm with dynamic ordering using retroactive heuristics (ABT_DO-Retro). It presents an example that shows how ABT_DO-Retro can enter an infinite loop following the natural understanding of the description g...
Chapter
This chapter proposes an algorithm that is based on nogood-based asynchronous forward-checking (AFC-ng) algorithm and is called asynchronous forward-checking (AFC)-tree algorithm. The main feature of the AFC-tree algorithm is using different agents to search non-intersecting parts of the search space concurrently. In AFC-tree, agents are prioritize...
Chapter
This chapter presents the new version 2.0 of the DisChoco platform for solving distributed constraint reasoning (DCR) problems. This version contains several interesting features: it is reliable and modular; it is easy to personalize and to extend; it is independent of the communication system; and it allows a deployment on a real distributed syste...
Book
DisCSP (Distributed Constraint Satisfaction Problem) is a general framework for solving distributed problems arising in Distributed Artificial Intelligence. A wide variety of problems in artificial intelligence are solved using the constraint satisfaction problem paradigm. However, there are several applications in multi-agent coordination that are...
Conference Paper
Full-text available
We recently proposed No good-Based Asynchronous Forward Checking (AFC-ng), an efficient and robust algorithm for solving Distributed Constraint Satisfaction Problems (DisCSPs). AFC-ng performs an asynchronous forward checking phase during synchronous search. In this paper, we propose two new algorithms based on the same mechanism as AFC-ng. However...
Article
Full-text available
The asynchronous backtracking algorithm with dynamic ordering (ABT_DO), proposed in Zivan and Meisels (Constraints 11(2–3):179–197, 2006), allows changing the order of agents during distributed asynchronous complete search. In a later study (Zivan et al., Constraints 14(2):177–198, 2009), retroactive heuristics which allowed more flexibility in the...
Conference Paper
Full-text available
Distributed constraint reasoning is a powerful concept to model and solve naturally distributed constraint satisfaction/optimization problems. How-ever, there are very few open-source tools dedicated to solve such problems: DisChoco, DCOPolis and FRODO. A distributed constraint reasoning platform must have some important features: It should be reli...
Conference Paper
Full-text available
Asynchronous Backtracking is the standard search procedure for distributed constraint reasoning. It requires a total ordering on the agents. All polynomial space algorithms proposed so far to improve Asynchronous Backtracking by reordering agents during search only allow a limited amount of reordering. In this paper, we propose Agile-ABT, a search...
Conference Paper
Full-text available
Résumé Le Backtracking Asynchrone est la procédure de recherche standard pour le raisonnement par contraintes distribué. Cette procédure nécessite un ordre total sur les agents. Tous les algorithmes avec une complexité spatiale polynomiale proposés jusqu'à présent pour améliorer le Backtracking Asynchrone ne permettent de réordonner les agents que...
Conference Paper
Full-text available
We propose two new asynchronous algorithms for solving Distributed Constraint Satisfaction Problems (DisCSPs). The first algorithm, AFC-ng, is a nogood-based version of Asynchronous Forward Checking (AFC). The second algorithm, Asynchronous Inter-Level Forward-Checking (AILFC), is based on the AFC-ng algorithm and is performed on a pseudo-tree orde...

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Projects

Project (1)
Archived project
Distributed Optimization