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Islamabad, Pakistan

Khan S.U.,Isra University of Pakistan | Qureshi I.M.,Air University | Qureshi I.M.,Institute of Signals | Zaman F.,IIU | And 3 more authors.
The Scientific World Journal | Year: 2014

Three issues regarding sensor failure at any position in the antenna array are discussed. We assume that sensor position is known. The issues include raise in sidelobe levels, displacement of nulls from their original positions, and diminishing of null depth. The required null depth is achieved by making the weight of symmetrical complement sensor passive. A hybrid method based on memetic computing algorithm is proposed. The hybrid method combines the cultural algorithm with differential evolution (CADE) which is used for the reduction of sidelobe levels and placement of nulls at their original positions. Fitness function is used to minimize the error between the desired and estimated beam patterns along with null constraints. Simulation results for various scenarios have been given to exhibit the validity and performance of the proposed algorithm. © 2014 S. U. Khan et al. Source

Atta-Ur-Rahman,Pmas Arid Agriculture University | Atta-Ur-Rahman,Institute of Signals | Zaidi D.-E.-N.,Pmas Arid Agriculture University | Salam M.H.,The University of Lahore | Jamil S.,Pmas Arid Agriculture University
13th International Conference on Hybrid Intelligent Systems, HIS 2013 | Year: 2014

In this paper a novel technique for user behavior classification is proposed using Fuzzy Rule Based System (FRBS). Using this technique a network user can be monitored and his/her behavior can be classified depending on his/her activities like unauthorized websites usage, attempting to breach in network security, firewalls, unauthorized services access and frequency of attempts etc. The information about a user is obtained by his/her web, database, hardware and other applications logs. FRBS classifies a user to one of the predefined categories based on the information extracted from user logs. This would great help in network security and privacy as well as users may be guided for sincere mistakes and other measures may be taken by the organization. Significance of the proposed scheme is shown by examples and results. © 2013 IEEE. Source

Basit A.,International Islamic University, Islamabad | Qureshi I.M.,Air University | Qureshi I.M.,Institute of Signals | Khan W.,International Islamic University, Islamabad | And 2 more authors.
International Journal of Antennas and Propagation | Year: 2014

A novel design of a cognitive radar (CR) hybridized with a phased array radar (PAR) having a low probability of intercept (LPI) transmit beam forming is proposed. PAR directed high gain property reveals its position to interceptors. Hence, the PAR high gain scanned beam patterns, over the entire surveillance region, are spoiled to get the series of low gain basis patterns. For unaffected array detection performance, these basis patterns are linearly combined to synthesize the high gain beam pattern in the desired direction using the set of weight. Genetic algorithm (GA) based evolutionary computing technique finds these weights offline and stores to memory. The emerging CR technology, having distinct properties (i.e., information feedback, memory, and processing at receiver and transmitter), is hybridized with PAR having LPI property. The proposed radar receiver estimates the interceptor range and the direction of arrival (DOA), using the extended Kalman filter (EKF) and the GA, respectively, and sends as feedback to transmitter. Selector block in transmitter gets appropriate weights from memory to synthesize the high gain beam pattern in accordance with the interceptor range and the direction. Simulations and the results validate the ability of the proposed radar. © 2014 Abdul Basit et al. Source

Atta-Ur-Rahman,Barani Institute of Information Technology | Atta-Ur-Rahman,Institute of Signals
2013 World Congress on Nature and Biologically Inspired Computing, NaBIC 2013 | Year: 2013

Optimum allocation of resources is demand of every modern communication system. In this way the transmission parameters like code rate, modulation size and power are optimally chosen to enhance the overall system throughput while satisfying certain constraints at the same time. A similar constrained optimization problem is focused for OFDM environment and solved by proposed Fuzzy Rule Based System (FRBS) and Particle Swarm Optimization (PSO). In this proposal FRBS is used for adapting code rate and modulation size while PSO is used for adaptive power. Significance of the proposed scheme is shown through the simulations. © 2013 IEEE. Source

Ghani A.,International Islamic University, Islamabad | Naqvi H.A.,International Islamic University, Islamabad | Sher M.,International Islamic University, Islamabad | Khan Z.S.,Institute of Signals | And 2 more authors.
Telecommunication Systems | Year: 2015

Due to resource limited nature of nodes in body area networks (BAN), it is often very difficult to replace or recharge its power source. To prolong the network’s life, only way out is energy efficient communication system. In this article an energy efficient communication system based on collaborative communication is proposed for BAN. Signals from the implanted nodes are received out-of-phase at the base station with no line-of-sight through an AWGN channel. Mathematical model derived here is based on three figures of merit i.e, received power, bit error rate and energy consumption. Analysis of the proposed model and Monte Carlo simulation show that the gain in received power increases as the number of collaborative nodes increase whereas BER is directly related to SNR (Formula presented.). To evaluate energy consumption of the proposed system, it is compared with single-input-single-output (SISO) system. In this comparison it has been found that SISO performs well at short distances but collaborative communication outperforms SISO in case of long distances. It is also found that collaborative communication requires “N (Formula presented.) Transmitted power”, less transmission power in comparison to SISO systems. It is observed that collaborative communication achieve energy saving very close to 99 %. On the basis of these results it is safe to recommend collaborative communication for resource limited BAN. © 2015 Springer Science+Business Media New York Source

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