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Islamabad, Pakistan

Bashir S.,Bahria University | Bashir S.,nnah University
Multimedia Tools and Applications | Year: 2015

Online opinions are one of the most important sources of information on which users base their purchasing decisions. Unfortunately, the large quantity of opinions makes it difficult for an individual to consume in a reasonable amount of time. Unlike standard information retrieval problems, the task here is to retrieve entities whose relevance is dependent upon other people’s opinions regarding the entities and how well those sentiments match the user’s own preferences. We propose novel techniques that incorporate aspect subjectivity measures into weighting the relevance of opinions of entities based on a user’s query keywords. We calculate these weights using sentiment polarity of terms found proximity close to keywords in opinion text. We have implemented our techniques, and we show that these improve the overall effectiveness of the baseline retrieval task. Our results indicate that on entities with long opinions our techniques can perform as good as state-of-the-art query expansion approaches. © 2015 Springer Science+Business Media New York Source

Tahir F.,Imperial College London | Ahmed Q.,Ohio State University | Bhatti A.I.,nnah University
Proceedings of the IEEE Conference on Decision and Control | Year: 2013

In this paper, we present a Switched-Decentralized Model Predictive Control (S-DMPC) scheme for the real-time flight control of a Twin Rotor System (TRS). Due to highly nonlinear dynamics and unavailability of full-state information, the linearized TRS model contains modelling (linearization) errors which cause poor state-estimation and lead to controller performance degradation. In order to address this problem, we propose an MPC-based control scheme in which, the associated (linear) observer's gain is switched according to the level of linearization error present in the model. Through experimental results, we show that the proposed S-DMPC scheme significantly improves TRS tracking in comparison to the Centralized-MPC as well as the individual (non-switched) Decentralized-MPC schemes. © 2013 IEEE. Source

Shah P.A.,Petronas University of Technology | Shah P.A.,COMSATS Institute of Information Technology | Yousaf M.,Riphah International University | Qayyum A.,nnah University | Hasbullah H.B.,Petronas University of Technology
2012 International Conference on Computer and Information Science, ICCIS 2012 - A Conference of World Engineering, Science and Technology Congress, ESTCON 2012 - Conference Proceedings | Year: 2012

With the advancement of technology and evolution of heterogeneous access networks, mobile devices are equipped with multiple network interfaces. Usually these mobile devices use single access network for communication, hence in case of node's mobility across heterogeneous networks this single network interface based communication results in higher handover delay and service disruption time. As today's mobile devices are multi-homed, and coverage area of different access networks usually overlap, hence mobile devices may have more than one active network interfaces. These active interfaces can be used simultaneously for communication. In this paper, we have discussed the effectiveness of multi-homing and parallel transmission during and after the vertical handover process. Results show that through the use of multi-homing and parallel transmission, handover delay and service disruption time can be reduced significantly and throughput can be increased. © 2012 IEEE. Source

Gillani S.A.,nnah University | Shah P.A.,Petronas University of Technology | Qayyum A.,nnah University | Hasbullah H.B.,Petronas University of Technology
Advances in Intelligent Systems and Computing | Year: 2015

Vehicular ad-hoc network (VANET) is a special form of mobile ad-hoc network (MANET) in which vehicles communicate with each other by creating an ad-hoc network. Before the deployment of VANET, it is necessary to address some important issues of VANET, specially concerning about architecture, routing, mobility, and security. Medium access control (MAC) protocols specify the way in which nodes share the underlying channel. As no standard exists for VANET, the research community has previously used IEEE 802.11a and 802.11b as the MAC layer access technologies. In this paper, we have discussed that the main challenge for VANET safety applications is to design an efficient MAC, so that all safety-related messages can be sent on time and such a protocol should be reliable because human lives are involved in the case of VANET. First, the challenges and requirements of a medium access protocol for VANET are discussed and then a survey of MAC solutions available in the literature to deal with these challenges in VANET is presented. © Springer Science+Business Media Singapore 2015. Source

Gillani S.,nnah University | Shahzad F.,National University | Qayyum A.,nnah University | Mehmood R.,University of Huddersfield
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

Vehicular Ad-hoc Networks (VANETs) are the most prominent enabling network technology for Intelligent Transportation Systems. VANETs provide many new exciting applications and opportunities albeit transportation safety and facilitation applications are their core drivers. Security of vehicular networks remains the most significant concern in VANETs deployment - because it is mandatory to assure public and transportation safety. In this paper, we review the various dimensions of VANETs security including security threats, challenges in providing security in vehicular networks environment, requirements and attributes of security solutions. We also provide taxonomy and critically review of the notable security solutions - available for VANETs in literature. © 2013 Springer-Verlag. Source

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