Hakima Chaouchi

Wireless sensor networks: a survey on recent developments and potential synergies

Wireless sensor network (WSN) has emerged as one of the most promising technologies for the future. This has been enabled by advances in technology and availability of small, inexpensive, and smart sensors resulting in cost effective and easily deployable WSNs. However, researchers must address a variety of challenges to facilitate the widespread deployment of WSN technology in real-world domains. In this survey, we give an overview of wireless sensor networks and their application domains including the challenges that should be addressed in order to push the technology further. Then we review the recent technologies and testbeds for WSNs. Finally, we identify several open research issues that need to be investigated in future.Our survey is different from existing surveys in that we focus on recent developments in wireless sensor network technologies. We review the leading research projects, standards and technologies, and platforms. Moreover, we highlight a recent phenomenon in WSN research that is to explore synergy between sensor networks and other technologies and explain how this can help sensor networks achieve their full potential. This paper intends to help new researchers entering the domain of WSNs by providing a comprehensive survey on recent developments.

Broker-based Cross-Cloud Federation Manager

Cloud federation is the next step in creating a new cloud computing ecosystem. The absence of suitable business models for federation managers is hindering the wide deployment of this critical feature. In this paper we will study existing federation managers, specifically CCFM (Cross-Cloud Federation Manager) and analyze its strengths and limitations. To overcome its limitations and make cloud federation more competitive in the current business trends, we introduce a new node called “broker” which will play a significant role in the enhanced CCFM mechanisms. The discovery and match-making agents in CCFM will be modified to enforce a new business model which is more interesting for private investors. Finally, our new business model will be discussed and possible versions are stated.

fractional frequency reuse for hierarchical resource allocation in mobile WiMAX networks

We propose a frequency planning based on zone switching diversity scheme for multicell OFDMA mobile WiMAX networks. In our approach, we focus on the use of Fractional Frequency Reuse (FFR) for guaranteeing the quality of service for the different service flows in the system. We investigate an architecture that coordinates the allocation of resources in terms of slots (the basic allocation unit in time and frequency domain in an OFDMA frame) between the Radio Resource Controller (RRC) and the Radio Resource Agent (RRA) which resides in the Base Station (BS). The proposed algorithm attempts to capture three types of diversity, namely, mutual interference diversity, traffic diversity, and selective fading channel diversity. As a consequence, the proposed algorithm for slot allocation makes a trade-off between maximizing overall throughput of the system while guaranteeing the Quality of Service (QoS) requirements for a mixture of real-time and non-real-time service flows under different diversity configurations. Our algorithm is evaluated under various cell configurations and traffic models. The results reveal important insights on the trade-off between cell interference suppression and QoS assurance.

Platform and experimentation of secure service location with P2P/Client-Server over ad hoc networks

Ad hoc networking is considered as an inexpensive solution for easy and fast wireless network coverage. However, for real service deployment, security and availability in such networks are still under research even though some experimentation has shown its viability. Additionally, peer-to-peer (P2P) networking has emerged as a key technology to enable resource sharing among users. As a result, the load charge on servers can be reduced by using P2P, but this approach presents a drawback related to the services availability; when a peer is not connected, its resources are not reachable. Alternatively, Client-Server architecture provides a centralized approach; but a high demand on client requests might deteriorate service response and capacity. In the case of ad hoc networks, offering services securely is even more challenging since all nodes are anonymous until being authenticated. In this paper, we propose to offer a secure location of services in an ad hoc environment. We focused on the development of a proxy-based solution to combine a P2P-client/server network overlay in order to provide securely the location information of network services (e.g. AAA service, Kerberos) and to set a platform that can include application services (e.g. multimedia content service). More precisely, we deployed a network overlay P2P platform using JXTA; a set of peer to peer protocols, and we developed simple peer nodes and a proxy server for providing and ensuring service access control. Other security services can also be deployed such as Kerberos, PKI, among others. In our platform, the JXTA was combined; through the proxy server, with a distributed Radius AAA server to perform authentication tasks prior to discovering the location of the required services in the ad hoc network. We added encryption and message authentication code mechanisms to provide a complete secured solution. GPS Bluetooth devices were used to obtain nodes location but other location systems are also possible. Finally, a detailed description of the system architecture and platform is provided describing all the modular components as well as numerical results derived from a simple test bed.

Privacy using mobile cloud computing

Crowdsourcing mobile applications are of increasing importance due to their suitability in providing personalized and better matching replies. Crowdsourcing location based services inherit the querying mechanism from its legacy predecessors and this is where the threat lays. In this paper we are going to prove mathematically that the mechanism with highest privacy level “Footprint” does not satisfy the privacy level needed by crowdsourced location based services and then prove that higher privacy level and lower overhead is achieved when these services are implemented in Operator centric mobile cloud architecture.

A Prediction Based Mobility Extension for eHIP Protocol

By revealing of heterogeneous networks, importance of cooperation of different technologies and mobility management became an important issue of wireless and mobile networks. The idea of separation the role of IP addresses for location and identification of a mobile node in the network has also increased its importance. In this study, our motivation is to extend our previously proposed handover management method (early update for host identity protocol (eHIP). We propose to introduce the idea of simply employing movement prediction idea to regular eHIP and so enhancing the handover latency.

Micro-economy effect on cloud federation

Cloud federation is considered the future of cloud providers, and for its importance, many researchers proposed federation mechanisms and automatic pricing schemes. To the best of our knowledge, all the proposed federation mechanisms fall in the same fatal hazard by selecting very far cloud providers to establish federation with and this severely decrements their customer satisfaction. In this paper, we raise the awareness on the hazards of price-based cloud selection mechanisms and propose views on how to solve the discussed hazards.