### Article de revue avec comité de lecture (9)

ANGILELLA Vincent, BEN-AMEUR Walid, CHARDY Matthieu**Design of fiber cable tree FTTH networks**. Electronic notes in discrete mathematics, february 2018, vol. 64, pp. 235-244

abstract

*This paper introduces the problem of backfeed fiber cables network design. It considers cable separation operations and costs as well as a non-linear cable line cost, and the feedback technique. An integer programming based solution is proposed, and some associated valid inequalities are introduced. The problem is proven to be NP-Hard. The formulation is assessed on real-life instances*

ANGILELLA Vincent, CHARDY Matthieu, BEN-AMEUR Walid**Fiber cable network design in tree networks**. European journal of operational research, september 2018, vol. 269, n° 3, pp. 1086-1106

abstract

*This work focuses on a fiber cable network design problem in the context of Fiber To The Home (FTTH) where separation techniques such as splicing and tapping are considered. Assuming the civil engineering structure is a tree, the problem is proven to be NP-hard and even hard to approximate. Two exact integer programming models taking into account some operator's engineering rules are introduced. Enhancements are provided for both models leading to significant computing time reduction. Computational experiments are performed on real-life instances with real costs including both manpower and material costs incurred by the network operator*

BEN-AMEUR Walid, DIDI BIHA Mohamed**A note on the problem of r disjoint (s,t)-cuts and some related issues**. Operations research letters, may 2018, vol. 46, pp. 335-338

abstract

*In this paper we consider the problem of finding a minimum-cost set of r disjoint (s, t)-cuts. We establish the link between this problem and some of its variations. We give a full description of the dominant of the convex hull of the incidence vectors of sets of r disjoint (s, t)-cuts. This generalizes the well-known result for the r = 1 case*

BEN-AMEUR Walid, GLORIEUX Antoine, NETO José**On the most imbalanced orientation of a graph**. Journal of combinatorial optimization, august 2018, vol. 36, n° 2, pp. 637-669

URL: https://hal.archives-ouvertes.fr/hal-01497902/document

abstract

*We study the problem of orienting the edges of a graph such that the minimum over all the vertices of the absolute difference between the outdegree and the indegree of a vertex is maximized. We call this minimum the imbalance of the orientation, i.e. the higher it gets, the more imbalanced the orientation is. The studied problem is denoted by MAXIM. We first characterize graphs for which the optimal objective value of MAXIM is zero. Next we show that MAXIM is generally NP-hard and cannot be approximated within a ratio of 1/2+ε for any constant ε>0 in polynomial time unless P=NP even if the minimum degree of the graph δ equals 2. Then we describe a polynomial-time approximation algorithm whose ratio is almost equal to 1/2. An exact polynomial-time algorithm is also derived for cacti. Finally, two mixed integer linear programming formulations are presented. Several valid inequalities are exhibited with the related separation algorithms. The performance of the strengthened formulations is assessed through several numerical experiments*

BEN-AMEUR Walid, GLORIEUX Antoine, NETO José**Complete formulations of polytopes related to extensions of assignment matrices**. Discrete optimization, 2018, pp. 1-15 (document in press - published online 04 May 2018)

abstract

*Let k, n denote two positive integers and consider the family of the polytopes defined as the convex hull of pairs of the form (Y, h) where Y is a 0/1-matrix with k rows, n columns, containing exactly one nonzero coefficient per column, and where h stands for the smallest index of a nonzero row of Y. These polytopes and some variants naturally emerge in formulations of different classical combinatorial optimization problems such as minimum makespan scheduling and minimum span frequency assignment. In this paper, we provide complete formulations for these polytopes and show the associated separation problem can be solved in polynomial time. The complete formulations in the original space of variables generally contain an exponential number of inequalities. Alternative extended compact formulations are also presented*

BEN-AMEUR Walid, OUOROU Adam, WANG Guanglei, ZOTKIEWICZ Mateusz**Multipolar robust optimization**. EURO journal on computational optimization, 2018, pp. 1-40 (document in press - published online 13 Dec 2017)

abstract

*We consider linear programs involving uncertain parameters and propose a new tractable robust counterpart which contains and generalizes several other models including the existing Affinely Adjustable Robust Counterpart and the Fully Adjustable Robust Counterpart. It consists in selecting a set of poles whose convex hull contains some projection of the uncertainty set, and computing a recourse strategy for each data scenario as a convex combination of some optimized recourses (one for each pole). We show that the proposed multipolar robust counterpart is tractable and its complexity is controllable. Further, we show that under some mild assumptions, two sequences of upper and lower bounds converge to the optimal value of the fully adjustable robust counterpart. We numerically investigate a couple of applications in the literature demonstrating that the approach can effectively improve the affinely adjustable policy*

CAO HUU Quyet, MADHUSUDAN Giyyarpuram, FARAHBAKHSH Reza, CRESPI Noel**Policy-based usage control for a trustworthy data sharing platform in smart cities**. Future generation computer systems (FGCS), 2018, pp. 1-13

abstract

*Although data is a key part in smart cities, traditionally there has been no systematic effort to enable the sharing of data in a trustworthy manner among applications or services. In order to promote sharing of data, mechanisms need to be put into place to provide the different actors - data producers, data consumers, etc. means to control and visualize how their data or requests are being processed and used. In this paper we deal with a key issue involved in trust which is usage control, i.e., how data is used once access to it has been granted. We propose a Data Usage Control Model (DUPO) to capture the diversity of obligations and constraints that data providers impose on the use of their data. Based on the DUPO model and semantic technologies, we propose a trustworthy data sharing platform which enhances transparency and traceability of data usage in smart cities. Lastly a proof-of-concept is developed to evaluate our solution and results show that the performance of the added trust does not impact negatively on the system*

EL-FAKIH Khaled, YEVTUSHENKO Nina, KUSHIK Natalia**Adaptive distinguishing test cases of nondeterministic finite state machines: test case derivation and length estimation**. Formal aspects of computing, march 2018, vol. 30, n° 2, pp. 319-332

abstract

*A top-down approach is presented for checking the existence and derivation of an adaptive distinguishing test case (called also an adaptive distinguishing sequence) for a nondeterministic finite state machine (NDFSM). When such a test case exists, the method returns a canonical test case that includes all other distinguishing tests of the given complete observable NDFSM. In the second part of the paper, a constructive approach is provided for deriving a class of complete observable NDFSMs with n states, n > 2, and 2^n − n − 1 inputs such that a shortest adaptive distinguishing test case for each NDFSM in the intended class has the length (height) 2^n − n − 1. In other words, we prove the reachability of the exponential upper bound on the length of a shortest adaptive distinguishing sequence for complete observable NDFSMs while for deterministic machines the upper bound is polynomial with respect to the number of states. For constructing the intended class of NDFSMs for a given n, we propose a special linear order over all the non-empty subsets without singletons of an n-element set. The obtained tight exponential upper bound initiates further research on identifying certain NDFSM classes where this upper bound is not reachable.*

SHU Lei , MUKHERJEE Mithun, PECHT Michael, CRESPI Noel, HAN Son**Challenges and research issues of data management in IoT for large-scale petrochemical plants**. IEEE systems journal, 2018, pp. 1-15

abstract

*The Internet of Things (IoT), which seamlessly interconnects heterogeneous devices with diverse functionalities, is an attractive choice for the large-scale petrochemical industry to develop an integrated system. With the industrial revolution, efforts have mainly been focused on factory automation, transportation security, and surveillance. The IoT plays a major role in factories with its new methods of data management and data collection. However, the IoT is still at an early stage in large-scale petrochemical plants due to the multiple coexisting heterogeneous networks in harsh and complex large-scale industrial networks. This paper presents a comprehensive survey on the IoT in large-scale petrochemical plants as well as recent activities in communication standards for the IoT in industries. This paper addresses the key enabling middleware approaches, e.g., an industrial intelligent sensing ecosystem (IISE), which allows rapid deployment and integration of heterogeneous wireless sensor networks with advancements in crowdsensing based services. In addition, this survey highlights the research issues of data management in the IoT for large-scale petrochemical plants*

### Communication dans une conférence à comité de lecture (5)

ANGILELLA Vincent, CHARDY Matthieu, BEN-AMEUR Walid**Fiber cable network design with operations administration & maintenance constraints**. ICORES 2018: 7th International Conference on Operations Research and Enterprise Systems, Setúbal : Scitepress, 24 january - 26 may 2018, Funchal, Portugal, 2018, pp. 94-105, ISBN 978-989-758-285-1

abstract

*We introduce two specific design problems of optical fiber cable networks that differ by a practical maintenance constraint. An integer programming based method including valid inequalities is introduced for the unconstrained problem. We propose two exact solution methods to tackle the constrained problem: the first one is based on mixed integer programming including valid inequalities while the second one is built on dynamic programming. The theoretical complexities of both problems in several cases are proven and compared. Numerical results assess the efficiency of both methods in different contexts including real-life instances, and evaluate the effect of the maintenance constraint on the solution quality*

CARVALLO Pamela, CAVALLI Ana Rosa, MALLOULI Wissam**A platform for security monitoring of multi-cloud applications**. PSI 2017 : 11th International Adrei Ershov Informatics Conference, Cham : Springer, 27-29 june 2017, Moscou, Russian Federation, 2018, pp. 59-71, ISBN 978-3-319-74312-7

URL: http://www.mallouli.com/recherche/publications/psi2017.pdf

abstract

*This paper presents a security assurance platform to monitor and control the security in the context of multi-cloud applications. Indeed, this property is a crucial issue in multi cloud-based environments where many aspects need to be faced, including risk management, data privacy and isolation, security-by-design applications, and vulnerability scans. Moreover, it also becomes necessary to have an efficient system that interrelates and operates all security controls that are configured and executed independently on each component of the system. In addition, as new attacks emerge every day, threat detection systems play a fundamental role in security monitoring schemes, identifying possible attacks. These systems handle an enormous volume of data, as they detect unknown malware by monitoring different activities from different points of observation, as well as adapting to new attack strategies and considering techniques to detect malicious behaviors and react accordingly. In this paper, we describe a monitoring platform for securing multi-cloud applications, from a Service Level Agreement perspective. Moreover, we present a case study depicting the multi-cloud monitoring of a smart-city transport application for the citizens of Tampere, Finland. Considering the nature of the application under study, the service requires continuous execution and availability functionalities, as end-users may utilize the service at any time*

DHAMAL Swapnil Vilas, BEN-AMEUR Walid, CHAHED Tijani, ALTMAN Eitan**Resource allocation polytope games: uniqueness of equilibrium, price of stability, and price of anarchy**. AAAI 2018 : 32nd AAAI conference on Artificial Intelligence, Palo Alto : Association for the Advancement of Artificial Intelligence, 02-07 february 2018, New Orleans, United States, 2018, pp. 997-1006

abstract

*We consider a two-player resource allocation polytope game, in which the strategy of a player is restricted by the strategy of the other player, with common coupled constraints. With respect to such a game, we formally introduce the notions of independent optimal strategy profile, which is the profile when players play optimally in the absence of the other player; and common contiguous set, which is the set of top nodes in the preference orderings of both the players that are exhaustively invested on in the independent optimal strategy profile. We show that for the game to have a unique PSNE, it is a necessary and sufficient condition that the independent optimal strategies of the players do not conflict, and either the common contiguous set consists of at most one node or all the nodes in the common contiguous set are invested on by only one player in the independent optimal strategy profile. We further derive a socially optimal strategy profile, and show that the price of anarchy cannot be bound by a common universal constant. We hence present an efficient algorithm to compute the price of anarchy and the price of stability, given an instance of the game. Under reasonable conditions, we show that the price of stability is 1. We encounter a paradox in this game that higher budgets may lead to worse outcomes*

HADDED Mohamed, LAOUITI Anis**A study on priority-based centralized TDMA slot scheduling algorithm for Vehicular Ad hoc NETworks**. CSCEET 2017 : 4th International Conference on Computer Science, Computer Engineering, and Education Technologies, Hong Kong : The Society of Digital Information and Wireless Communications, 26-28 april 2017, Beirut, Lebanon, 2018, vol. 8, n°2, pp. 124-128, ISBN 2412-6551

URL: http://sdiwc.net/digital-library/request.php?article=e11a7ad81a1dbda0b83a28ab03bb176f

abstract

*Vehicular Ad hoc NETworks, known as VANETs, are deployed to reduce the risk of road accidents as well as to improve passenger comfort by allowing vehicles to exchange different kinds of data. Medium Access Control protocols play a primary role in providing efficient delivery while minimizing data packet loss. In fact, one of the major challenges of vehicular networks is designing an efficient MAC protocol which can cope with the frequent changes in topology and the different Quality of Service QoS requirements of VANET applications. However, safety applications of VANETs require that vehicles should be able to disseminate messages quickly to their neighboring vehicles with a high degree of reliability and by giving a higher priority to sensitive data to get access to the network. In this paper, we propose a Priority-based Qos Centralized Tdma MAC protocol (PQCTMAC) for vehicular networks in which data priority levels are used to differentiate among slot reservation requests. The main goal of this work is to propose a priority-based scheduling algorithm to make better the use of the single common channel by giving high access priority to safety traffic. Simulation results showed that PQCTMAC significantly improves the efficiency of safety message broadcasting in VANET*

HASROUNY Hamssa, SAMHAT Abedellatif, BASSIL Carole, LAOUITI Anis**Trust model for group leader selection in VANET**. CSCEET 2017 : 4th International Conference on Computer Science, Computer Engineering, and Education Technologies, Hong Kong : The Society of Digital Information and Wireless Communications, 26-28 april 2017, Beirut, Lebanon, 2018, vol. 8, n°2, pp. 139-143, ISBN 2412-6551

URL: http://sdiwc.net/digital-library/request.php?article=291e882d3cffcf1675a19f9d6dbf574f

abstract

*In this paper, we propose a Trust Model for VANETs. It is a combination between centralized and distributed cooperation between vehicles and infrastructure to achieve the selection of the trustiest node as a Group Leader. The proposed model is based on different metrics to analyse the behaviour of the vehicles in the group while preserving the privacy of the participants and maintaining low network overhead. The evaluation of the proposed trust model is done by simulations using GrooveNet. Results show the efficiency of the proposed model to select the trusty vehicles*

Modifié le 20 octobre 2012