Article de revue avec comité de lecture (7)
BEN-AMEUR Walid, DIDI BIHA Mohamed
On the minimum cut separator problem. Networks, january 2012, vol. 59, n° 1, pp. 30-36
abstract
Given G = (V,E) an undirected graph and two specified nonadjacent nodes a and b of V, a cut separator is a subset F =delta (C) E such that a,b are in V / C and a and b belong to different connected components of the graph induced by V / C. Given a non-negative cost vector, the cut separator problem is to find a cut separator of minimum cost. This new problem can be seen as a generalization of the vertex separator problem. In this article, we give a polynomial time algorithm for this problem. We also present six equivalent linear programming formulations, and we show their tightness. Using these results we obtain an explicit short polyhedral description of the dominant of the cut separator polytope.
HUANG Cuiting, LEE Gyu Myoung, CRESPI Noel
A semantic enhanced service exposure model for a converged service environment. IEEE communications magazine, march 2012, vol. 50, n° 3, pp. 32-40
abstract
Service exposure, as a prerequisite for the reuse of existing services, plays a significant role in next-generation service delivery. However, some issues such as cross-domain interoperability and user-centricity are still unresolved. Therefore, this article proposes a semantic enhanced converged service exposure model that enables services derived from different domains (i.e., telecom/web/device/user) to be integrated into a composite service regardless of their underlying heterogeneities. Meanwhile, the user-centric feature is enhanced by applying the semantic annotation to both the service description and the user request, as well as empowering a user to publish and share his/her created service in a user-friendly way. Moreover, a variety of interfaces, including APIs, widgets, and natural-language-based tools, are provided to satisfy the multilevel user requirements, enabling users to profit from a highly personalized, meaningful communication and interaction experience.
LAGA Nassim, BERTIN Emmanuel, GLITHO Roch, CRESPI Noel
Widgets and composition mechanism for service creation by ordinary users . IEEE communications magazine, march 2012, vol. 50, n° 3, pp. 52-60
abstract
Significant research work has been conducted in software engineering to facilitate and speed up the process of service creation by experienced developers. Recently, however, service creation by ordinary users has attracted more and more attention as non-technical people have begun to play an active role in service life cycles, especially in a Web 2.0 context. In addition, service creation by ordinary users tackles the heterogeneity, the dynamicity, and the spontaneous nature of users needs. We show that current technologies are mainly inspired by previous approaches and architectures conceived for experienced developers, which means that they are not really adequate for service creation by ordinary users. This article proposes a novel service creation environment for ordinary users. It is made up of a new Widget abstraction layer that exposes the graphical user interface of services as reusable components, and relies on a two-step mechanism to compose these services at runtime. A proof of concept prototype has been built. The new abstraction layer offers interfaces that are much more user friendly than the current service creation tools. It also enables the different capabilities of a service to be seamlessly handled throughout its usage lifecycle.
SONG Songbo, MOUSTAFA Hassnaa, AFIFI Hossam
IPTV services personalization using context-awareness. Informatica, 2012, vol. 36, n° 1, pp. 13-20
abstract
The advances in IPTV (Internet Protocol Television) technology enable a new user-centric and interactive TV model, in which context-awareness is promising in making the user's interaction with the TV dynamic and transparent. Our research interest is how to achieve user-centric personalized IPTV services applying context-awareness. In this paper, we present a solution for IPTV services personalization introducing context-awareness on top of the IPTV architecture on one hand to gather different information about the user and his environment and on the other hand allowing each user to be distinguished to the system in a unique manner. Consequently, IPTV services personalization is achieved in a real-time manner for each user. We implemented the proposed solution on top of an IPTV platform considering the NGN IPTV architecture as a proof of concept and as a means to evaluate the performance.
SONG Songbo, MOUSTAFA Hassnaa, AFIFI Hossam
A survey on personalized TV and NGN services through context-awareness. ACM computing surveys, january 2012, vol. 11, n° 1
abstract
The advances in IPTV (Internet Protocol Television) technology enable a new user-centric and interactive TV model, in which context-awareness is promising in making the user's interaction with the TV dynamic and transparent. Our research interest is how to achieve TV service personalization applying context-awareness to the NGN IPTV architecture. In this article we present the different existing contributions that employ context-awareness to allow interactive services. Some of these contributions directly focus on TV, while others are proposed for specific NGN services. We present a technical analysis for these solutions and give some guidelines for future deployment of personalized IPTV services.
SYUE Syue-Ju, WANG Chin-Liang , AGUILAR Teck, GAUTHIER Vincent, AFIFI Hossam
Cooperative geographic routing with radio coverage extension for SER-constrained wireless relay networks. IEEE journal on selected areas in communications, february 2012, vol. 30, n° 2, pp. 271-279
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abstract
Cooperative communication for wireless networks has been extensively investigated from the perspective of physical-layer design. However, the impact of physical-layer cooperation on the network-layer routing design still remains unclear. In this paper, we examine the potential benefit of radio coverage extension from cooperation, and present how to incorporate this feature into the routing design. Specifically, with a series of mathematical formulations and derivations, we quantitatively identify direct and cooperative radio coverages based on the average symbol error rate (SER) performance requirement, elucidating how cooperative diversity gain can be translated into radio coverage extension. We then propose a cooperative geographic routing protocol with cross-layer design, namely the Relay-Aware Cooperative Routing (RACR) protocol, that exploits the merit of radio coverage extension for improving the non-cooperative geographic routing. Simulation results show that the RACR protocol performs significantly better than the non-cooperative geographic routing in terms of the average path length in dense ad hoc networks.
ZHANG Hongguang, BOUTABIA Mohammed, NGUYEN Hang, CRESPI Noel, PANG Ai-Chun, ZHOU Liang, WEI Jianming
Mobile WiMAX field trial test through multimedia performance evaluation. EURASIP journal on wireless communications and networking, february 2012
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abstract
IEEE 802.16e is a mobile version of Worldwide Interoperability for Microwave Access (WiMAX) that plays an important role in the evolution towards 4G. In this work, we focus on multimedia performance measurement for the purpose of a more realistic mobile WiMAX network test. Our work aims to make a contribution in better understanding the mobile WiMAX performance for multimedia applications. For that purpose, we employ Voice over Internet Protocol (VoIP) and video streaming to test the network performance, where two distinct evaluation systems are used, professional and user-friendly. Our test results show that the mobile WiMAX network can support well the bandwidth-intense and delay-sensitive multimedia application. We find that the VoIP quality at the cell center is perfect, where the value of Perceptual Evaluation of Speech Quality (PESQ) exceeds 4. At the cell edge, the quality is degraded but still adequate. We also observe that the downlink of mobile WiMAX network can support video streaming up to 4 Mbps with the Mean Opinion Score (MOS) value of 4.5. On the uplink, the bitrate of 1Mbps is supported with MOS 4.5 at the cell center and with MOS 3.2 at the cell edge respectively. Our experiments further indicate that a smooth playback of YouTube 480P video is consistently provided. Finally, the handover case has very limited impact to the overall quality degradation of both VoIP and video streaming.
Communication dans une conférence à comité de lecture (6)
FLOREA Alina Alexandra, MARTINOD Laurent , MÈGE Philippe, NGUYEN Hang
Multi-layer realistic voice capacity evaluation in LTE rel. 9 and performance comparison with PMR and GSM. WTC '12 : World Telecommunications Congress , IEEE, 04-07 march 2012, Miyazaki, Japan, 2012, pp. 1-6, ISBN 978-1-4577-1459-7
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abstract
This paper proposes a multi-layer realistic voice capacity evaluation method for long term evolution (LTE) Release 9 downlink transmission, from a private mobile radio (PMR) perspective. The obtained voice spectral efficiency is also compared with existent PMR networks and global system for mobile communications (GSM). The realistic system model considers both transmission protocols overhead, including internet protocol (IP) and robust header compression (ROHC), and air frame overhead. As LTE is not designed for low bit rate voice communications, we propose to optimize the layer one transmission parameters. We modify the standard algorithm by calculating the minima normalized values for both coding rate and transport block size, considering radio allocation possibilities. The newly computed values are optima for PMR voice transmission. The LTE voice communications capacity is given for the realistic and ideal values of the protocol stack overhead. The realistic results are compared to GSM and PMR voice spectral efficiencies, with the appropriate voice coders. LTE Release 9 seems promising for future data transfers, but is not yet favourable to voice services. Even though the air frame is highly configurable, the protocol stack overhead and the standard resource allocation constraints are not designed for real-time voice packets transmission. The ROHC compressed protocol overhead remains large for voice frames and demands important air resources. On the other hand, resource allocation is not foreseen for small packets transmission. Considering the proposed allocation algorithm, results show that the voice capacity may double if the protocol overhead only were reduced to ideal values.
HADJI Makhlouf, ZEGHLACHE Djamal
Minimum Cost Maximum Flow Algorithm for Dynamic Resource Allocation in Clouds. IEEE Cloud 2012, IEEE, USA : IEEE, 24-29 june 2012, Honolulu, United States, 2012, pp. 1-7 (document in press)
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abstract
A minimum cost maximum flow algorithm is proposed
for resources (e.g. virtual machines) placement in clouds
confronted to dynamic workloads and flows variations. The
algorithm is compared to an exact method generalizing the
classical Bin-Packing formulation using a linear integer program.
A directed graph is used to model the allocation problem for
cloud resources organized in a finite number of resource types; a
common practice in cloud services. Providers can use the minimum
cost maximum flow algorithm to opportunistically select the
most appropriate physical resources to serve applications or to
ensure elastic platform provisioning. The modified Bin-Packing
algorithm is used to benchmark the minimum cost maximum
flow solution. The latter combined with a prediction mechanism
to handle dynamic variations achieves near optimal performance.
for resources (e.g. virtual machines) placement in clouds
confronted to dynamic workloads and flows variations. The
algorithm is compared to an exact method generalizing the
classical Bin-Packing formulation using a linear integer program.
A directed graph is used to model the allocation problem for
cloud resources organized in a finite number of resource types; a
common practice in cloud services. Providers can use the minimum
cost maximum flow algorithm to opportunistically select the
most appropriate physical resources to serve applications or to
ensure elastic platform provisioning. The modified Bin-Packing
algorithm is used to benchmark the minimum cost maximum
flow solution. The latter combined with a prediction mechanism
to handle dynamic variations achieves near optimal performance.
LAGA Nassim, BERTIN Emmanuel, CRESPI Noel
Promoting mashup creation through unstructured data extraction . ICOIN '12 : International Conference on Information Networking, IEEE, 01-03 february 2012, Bali, Indonesia, 2012, pp. 59-64 , ISBN 978-1-4673-0251-7
[PDF]
abstract
Service composition tools are usually based on an input/output mapping pattern. Inputs and output are declared by the service developer when publishing his service. However, services might also generate unstructured data such as email and instant messages content. That data are hardly expectable by developers. Consequently, much data are unavoidably left out by current service composition tools. In this paper we firstly propose and implement an enhancement to current SOA in order to facilitate capturing unstructured data. Secondly, we define and implement a new service composition pattern and tool in order to enable end-users to easily create Mashups based on structured and unstructured data (unstructured data are neither declared nor formatted by the service developer when publishing services). Finally, we validate this proposal by creating a rich communication environment using the composition tool we have implemented. As a consequence, this work impacts significantly service composition research communities by introducing a novel architecture and a new pattern for composing services.
LAGHARI Khalil Ur Rehman, KHAN Imran, CRESPI Noel
Quantitative and qualitative assessment of QoE for multimedia services in wireless environment. MoVid '12 : The 4th Mobile Video workshop, New-York : ACM, 24 february 2012, Chapel Hill, North Carolina, United States, 2012, pp. 7-12, ISBN 978-1-4503-1166-3
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abstract
Quality of Experience (QoE) is emerging as the holy grail of human-centric multimedia services. QoE is a multi-disciplinary field based on social psychology, cognitive science, economics and engineering science, focused on understanding overall human quality of experience requirements. QoE has been viewed as the pivotal set of metrics in determining the success or failure of any product or service. In real time environment, QoE is influenced by multiple service factors such as application and network level QoS parameters, content, and business aspects. We emulate wireless environment and analyze the combined impact of the network and application level QoS parameters and content characteristics over user perceived quality for video streaming service. We use Rough Set Theory (RST) for quantitative assessment and simple CCA frame work for qualitative assessment of user data in order to understand the influence of multiple multimedia service parameters over QoE.
PENGYAN Yao, HU Zheng, CRESPI Noel, ZHAO Zhenzhen
A study of social behavior in collaborative user generated services. ICUIMC '12 or IMCOM '12 : ACM International Conference on Ubiquitous Information Management and Communication , New-York : ACM, 20-22 february 2012, Kuala Lumpur, Malaysia, 2012, ISBN 978-1-4503-1172-4
abstract
User-generated content has become more and more popular. The success of collaborative content creation such as Wikipedia shows the level of user's accomplishments in knowledge sharing and socialization. In this paper we extend this research in the service domain, to explore users' social behavior in Collaborative User-Generated Services (Co-UGS). We create a model which is derived from a real social network with its behavior being similar to that of Co-UGS. The centrality approach of social network analysis is used to analyze Co-UGS simulation on this model. Three Co-UGS network actors are identified to distinguish users according to their reactions to a service, i.e. ignoring users, sharing users and co-creating users. Moreover, six hypotheses are proposed to keep the Co-UGS simulation. The results show that the Co-UGS network constructed by the sharing and co-creating users is a connected group superimposed on the basis of the social network of users. In addition, the feasibility of this simulation method is demonstrated along with the validity of applying social network analysis to the study of users' social behavior in Co-UGS.
ZHAO Zhenzhen, LIU Ji, CRESPI Noel
Dig-event : let's socialize around events. CSCW '12 : The ACM Conference on Computer Supported Cooperative Work, New-York : ACM, 11-15 february 2012, Seattle, United States, 2012, pp. 279-280, ISBN 978-1-4503-1051-2
[PDF]
abstract
Traditional social networks socialize around the contents that have uploaded to these sites and discover interesting contents uploaded by others. In this demo we aim to explore the idea of activity-oriented social networks. We design a novel social networking site called Dig-Event (Do-it-together Event), where people are able to share events through calendar, while discover interesting events shared by others. Our demo has been inspired by previous research on calendaring and popular social network applications like Facebook and Google+. It allows users to share their activities to the customized social circle, conduct events by selecting activity-based gadgets. The features of event recommendation and integration with existing social networks further boost the event socialization experience.
