Awais M.,Namal College |
Qureshi J.,Namal College
IET Communications | Year: 2017
In this study the authors consider the scenario of multiple unicast flows intersecting a common router in an opportunistic wireless network. Instead of forwarding packets in each of the flows independently, the router can perform inter-session network coding and transmit codewords to improve the network throughput. Unlike coding for multicast data flow for which an optimal code can be constructed in polynomial time, coding for unicast data flows is a more complicated coding problem and has been shown to be an NP-hard problem. Opportunities for inter-session network coding have also been shown to exist in single-hop wireless data dissemination network such as Wi-Fi and WiMAX networks. In this study the authors propose an efficient coding scheme for unicast flows and demonstrate its higher coding gain over previously proposed state-of-the-art coding schemes, validated using simulation results and wireless sensor network testbed packet reception traces. The authors also show that the proposed algorithm is optimal for all 238 non-isomorphic coding instances for instances for n≤4, and for 9500 of the 9608 non-isomorphic coding instances for n = 5, where n is the number of unicast packets. © The Institution of Engineering and Technology 2017.
Shehzad M.K.,Namal College |
Ahmed A.,Namal College
ACM International Conference Proceeding Series | Year: 2016
Spectrum sensing (signal detection) under low signal to noise ratio is a fundamental problem in cognitive radio networks. In this paper, we have analyzed maximum eigenvalue detection (MED) and energy detection (ED) techniques known as semi-blind spectrum sensing techniques. Simulations are performed by using independent and identically distributed (iid) signals to verify the results. Maximum eigenvalue detection algorithm exploits correlation in received signal samples and hence, performs same as energy detection algorithm under high signal to noise ratio. Energy detection performs well under low signal to noise ratio for iid signals and its performance reaches maximum eigenvalue detection under high signal to noise ratio. Both algorithms don't need any prior knowledge of primary user signal for detection and hence can be used in various applications. © 2016 ACM.
Farooq M.U.,Petronas University of Technology |
Asif M.,COMSATS Institute of Information Technology |
Nabi S.W.,Namal College |
Qureshi M.A.,COMSATS Institute of Information Technology
Proceedings - 10th International Conference on Frontiers of Information Technology, FIT 2012 | Year: 2012
A RFID system's front-end consists of multiple tags being identified by a single (or multiple) reader. In order for the reader to uniquely identify all tags within certain range, some sort of anticollision mechanism is required. ALOHA and its variations can be used in such a scenario. EPC Global, a standardizing body for RFID technology, has proposed a Dynamic Framed Slotted ALOHA mechanism for UHF passive tags (Gen 2, Class I), and a 'Q' algorithm is used to dynamically update the size of the frame, where the size changes exponentially. Two parameters that define this Q algorithm are the initial size of the frame and the speed of frame-size estimation. In this paper we present a complete RFID system simulator which can be used to investigate various algorithms in various scenarios, in context of UHF RFID systems, and then present our simulation setup, results and analysis where the throughput for different traffic scenarios is calculated. Based on the results the trend and the optimal values are discussed for the two parameters. These results can be used by an RFID system designer to choose the right initial parameters, based on an order-of-magnitude estimate of the traffic conditions. © 2012 IEEE.
Hussain M.A.,Namal College |
Badar R.,COMSATS Institute of Information Technology
Proceedings - 2015 13th International Conference on Frontiers of Information Technology, FIT 2015 | Year: 2015
Transmission of sensitive data over some channel is a highly security constrained scenario and thus demands the application of some encryption algorithm. It is better to implement the algorithm in hardware as compared to software due to better computational speed and memory usage. Tiny Encryption Algorithm known as TEA block cipher is a light-weight and efficient cryptographic algorithm, well suited for wireless communication systems. This paper presents the successful implementation of TEA on FPGA for different design approaches to analyze the performance and resource utilization against each design approach. © 2015 IEEE.
Kashif M.F.,Namal College |
Rashid A.K.,Namal College
2016 International Conference on Intelligent Systems Engineering, ICISE 2016 | Year: 2016
A novel multilevel inverter topology with reduced number of power switches is proposed. This new topology is based on a combination of conventional diode clamped and H-bridge topologies. The proposed idea has been validated through simulation results. © 2016 IEEE.
Qureshi J.,Namal College |
Malik A.,Namal College
2015 IEEE 20th International Workshop on Computer Aided Modelling and Design of Communication Links and Networks, CAMAD 2015 | Year: 2015
It is a well-known result that constructing code-words over GF(2) to minimize the number of transmissions for a single-hop wireless multicasting is an NP-complete problem. Linearly independent codewords can be constructed in polynomial time for all the n clients, known as maximum distance separable (MDS) code, when the finite field size q is larger than or equal to the number of clients, q ≥ n. In this paper we quantify the exact minimum number of transmissions for a multicast network using erasure code when q = 2 and n = 3, such that q < n. We first show that the use of Markov chain model to derive the minimum number of transmissions for such a network is limited for very small number of input packets. We then use combinatorial approach to derive an upper bound on the exact minimum number of transmissions. Our results show that the difference between the expected number of transmissions using XOR coding and MDS coding is negligible for n = 3. © 2015 IEEE.
Qureshi J.,Namal College
Proceedings - Conference on Local Computer Networks, LCN | Year: 2014
The index coding problem is a fundamental transmission problem arising in content distribution and wireless networks. Traditional approach to solve this problem is to find heuristic/ approximation minimum clique partition solution on an appropriately mapped graph of the index coding problem. In this paper we study index code for unicast data flow for which we propose updated clique index coding (UCIC) scheme, UCIC piggybacks additional information in the coded symbol such that an unsatisfied client can update its cache. We show that UCIC has higher coding gain than previously proposed index coding schemes, and it is optimal for those instances where index code of minimum length is known. © 2014 IEEE.
Khan M.J.,Namal College
International Conference on Self-Adaptive and Self-Organizing Systems, SASO | Year: 2015
Software engineering literature is rich in terms of various architectural options to build conventional software systems but very less efforts have been put forward for generic architectures to build autonomic systems. This position paper presents a hierarchical generic service oriented architecture for developing autonomic systems. © 2015 IEEE.
Khan C.,Namal College |
Khan M.J.,Namal College
Proceedings - 2016 IEEE International Conference on Autonomic Computing, ICAC 2016 | Year: 2016
Designing efficient self-management algorithms for autonomic managers has been an ongoing and evolving research area. In literature, many machine learning paradigms have been proposed and exploited to make effective decisions in autonomic managers. This position paper proposes to optimize the decision making algorithm closer to the nature inspired decision making process. Core of the proposed framework is case-based reasoning which is an incremental learning mechanism for solving new system problems using the past experience. Fuzzy clustering has been proposed to maintain the knowledge-base of past problems in autonomic managers. New monitored problem in autonomic manager seeks fuzzy memberships amongst different clusters in the knowledge-base and problem solver in autonomic manager exploits existing solutions in different clusters with respect to their fuzzy membership value. It has been tested on a simulated case-study of Autonomic Forest Fire Application and up to 88% accurate predictions have been observed. © 2016 IEEE.
Khan M.J.,Namal College
IET Software | Year: 2014
Domain knowledge for various decision-making activities of Software Engineering (SE) is rarely available in a structured or well-formalised form. Owing to lack of the well-informed knowledge, decision making for different kinds of predictions and estimations in SE domain is a challenge. Maintenance and elicitation of domain knowledge is an overwhelming task and causes the knowledge acquisition bottleneck. Most of the artificial intelligence techniques of prediction and estimation do not work in absence of complete and structured knowledge. Case-based reasoning (CBR) is a lazy learning paradigm of artificial intelligence which takes care of this challenge and helps to reduce the knowledge availability bottleneck. This technique exploits the similar experience of past which may be available in unstructured form, and improves its learning curve with passage of time. In literature, CBR has been successfully applied in various areas of SE, but there is lack of single systematic panoramic picture which might have highlighted the potential research questions in this direction. In this study, the author has presented a comprehensive and panoramic systematic mapping study of various CBR applications in SE domain, and identified some promising future research directions. © The Institution of Engineering and Technology 2014.