N. Ghani

University of New Mexico, Albuquerque, New Mexico, United States

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Publications (161)113.82 Total impact

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    ABSTRACT: Packet loss of video streams cannot be avoided at wireless links for limited wireless bandwidth and frequently changed environments. To provide differentiated Quality of Service (QoS) guarantees between multimedia and data services, IEEE 802.11e was proposed. However, its performance and flexibility need to be further improved. In this paper, after a survey on various modifications of IEEE 802.11e, we formulate the problem of video transmission over IEEE 802.11e networks to help scheme design and performance analysis. Then accompanied with in-depth analysis, an adaptive unequal protection schema is proposed, which is composed of three mechanisms: (1) Insert each video packet into the access category (AC) with the minimum relative queuing delay; (2) Assign each packet dynamically to a proper AC based on several parameters to guarantee the transmission of high priority frames; (3) Apply fuzzy logic controllers to adjust parameters so as to reply quickly to the variation of video data rate, coding structure and network load. Finally, regarding MPEG-4 codec as the example, we perform extensive evaluations and validate the effectiveness and flexibility of proposed scheme. Simulations are divided into WLAN and multihop parts, involving different video sequences and various traffic modes of data streams. Beside performance comparison between proposed scheme and other ones, influence of parameter setting and combination with routing algorithms are also evaluated.
    Multimedia Tools and Applications 09/2014; · 1.06 Impact Factor
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    ABSTRACT: A scalable and analytically tractable probabilistic model for the cascading failure dynamics in power grids is constructed while retaining key physical attributes and operating characteristics of the power grid. The approach is based upon extracting a reduced abstraction of large-scale power grids using a small number of aggregate state variables while modeling the system dynamics using a continuous-time Markov chain. The aggregate state variables represent critical power-grid attributes, which have been shown, from prior simulation-based and historical-data-based analysis, to strongly influence the cascading behavior. The transition rates among states are formulated in terms of certain parameters that capture grid's operating characteristics comprising loading level, error in transmission-capacity estimation, and constraints in performing load shedding. The model allows the prediction of the evolution of blackout probability in time. Moreover, the asymptotic analysis of the blackout probability enables the calculation of the probability mass function of the blackout size. A key benefit of the model is that it enables the characterization of the severity of cascading failures in terms of the operating characteristics of the power grid.
    IEEE Transactions on Power Systems 07/2014; 29(4):1767-1779. · 3.53 Impact Factor
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    ABSTRACT: This paper studies reconfiguration design for cloud-based virtual network services mapped over optical substrates. A novel scheme is proposed to improve resource efficiency and its results are analyzed versus some existing strategies.
    Optical Fiber Communication Conference; 03/2014
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    ABSTRACT: Natural and man-made disasters, such as tsunamis, earthquakes, floods, and epidemics pose a significant threat to human societies. To respond to emergencies in a fast and an effective manner, Multi-Criteria Decision Making (MCDM) is very important for the decision-making process. The provision of information concerning the ''ground-zero'' situation to the emergency management stakeholders is an essential prerequisite for MCDM. In this paper, we propose a strategy to form a community-based virtual database, which connects local resource databases of suppliers that provide information and human resources for emergency management. Such a virtual database enables collaborative information sharing among community-based NGOs, public, and private organizations within a community. Moreover, to mobilize resources, the aforementioned process raises awareness within the community and aids in assessing local knowledge and resources. In our work, we present the design, implementation, and evaluation of such a community-based database, which maximally utilizes all of the available information and network resources of a community to better manage natural and man-made disasters.
    Computers & Operations Research 02/2014; 42:116-124. · 1.72 Impact Factor
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    ABSTRACT: An efficient resource allocation is a fundamental requirement in high performance computing (HPC) systems. Many projects are dedicated to large-scale distributed computing systems that have designed and developed resource allocation mechanisms with a variety of architectures and services. In our study, through analysis, a comprehensive survey for describing resource allocation in various HPCs is reported. The aim of the work is to aggregate under a joint framework, the existing solutions for HPC to provide a thorough analysis and characteristics of the resource management and allocation strategies. Resource allocation mechanisms and strategies play a vital role towards the performance improvement of all the HPCs classifications. Therefore, a comprehensive discussion of widely used resource allocation strategies deployed in HPC environment is required, which is one of the motivations of this survey. Moreover, we have classified the HPC systems into three broad categories, namely: (a) cluster, (b) grid, and (c) cloud systems and define the characteristics of each class by extracting sets of common attributes. All of the aforementioned systems are cataloged into pure software and hybrid/hardware solutions. The system classification is used to identify approaches followed by the implementation of existing resource allocation strategies that are widely presented in the literature.
    Parallel Computing 11/2013; 39(11):709–736. · 1.89 Impact Factor
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    ABSTRACT: The advance reservation (AR) of connections is becoming an increasingly important requirement for many emerging commercial bandwidth and scientific computing users. However, most studies in this area have focused on scheduling algorithm design and have not addressed implementation challenges in larger realistic networking environments, particularly multidomain. As a result, this paper develops a detailed solution for distributed AR in multidomain networks. Novel link-state routing extensions and update triggering policies are introduced to exchange interdomain bandwidth-timeline state information. Distributed path scheduling algorithms are then designed to leverage this state and schedule user requests across domains based upon various traffic engineering policies. The proposed solutions are then analyzed in detail using network simulation.
    IEEE Systems Journal 06/2013; PP(99):1-10. · 1.75 Impact Factor
  • F. Gu, H. Alazemi, A. Rayes, N. Ghani
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    ABSTRACT: Many users are adopting cloud computing services to expand applications across interconnected data-centers. Since these new paradigms require common data exchange, they impose further virtual network (VN) mapping demands for operators. However, to guarantee reliable services, survivability is a key concern, especially for large regional stressors. Hence this paper presents a novel failure region-disjoint VN mapping scheme to achieve efficient survivability. Namely, the solution divides failure regions into two groups and then computes failure region-disjoint VN mapping pairs. The scheme is analyzed using simulation and compared against some existing survivable VN mapping schemes.
    Computing, Networking and Communications (ICNC), 2013 International Conference on; 01/2013
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    ABSTRACT: A multi-objective optimization model is developed for lightpath provisioning in hierarchical multi-domain optical networks. The proposed formulation is then solved and its results compared against some existing distributed heuristic strategies.
    Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference (OFC/NFOEC), 2013; 01/2013
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    ABSTRACT: Multi-domain optical network provisioning is a key focus area as users continue to demand scalable bandwidth services across wider network regions. To date, a range of distributed schemes have been proposed to achieve lightpath routing across domain boundaries. In general, these solutions rely upon hierarchical routing and provisioning strategies and are mostly heuristics based. As such, it is difficult to gauge their true load-carrying capacity and effectiveness. Hence in order to address this concern, this effort proposes a formal optimization-based model for multi-domain lightpath setup pursuant to several key objectives, i.e., including throughput maximization, resource minimization, and load balancing. This model is then solved for some sample network topologies, and the results are compared versus existing heuristic strategies.
    Journal of Optical Communications and Networking 01/2013; 5(12):1413-1424. · 1.55 Impact Factor
  • J. Crichigno, J. Khoury, N. Ghani
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    ABSTRACT: We present a routing scheme for MPLS networks with probabilistic failures. Our routing scheme simultaneously maximizes the expected satisfied demand and minimizes the maximum link utilization of the network. Our approach is novel in that it is the first to jointly address the traffic engineering and the routing through reliable paths problems. In addition to the optimal routing algorithm, we present a lower complexity heuristic algorithm based on Linear Programming and Yen's algorithm. Finally, numerical results are presented to demonstrate the effectiveness of both our optimal and heuristic algorithms.
    Communications (ICC), 2013 IEEE International Conference on; 01/2013
  • F. Gu, M. Peng, S. Khan, A. Rayes, N. Ghani
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    ABSTRACT: This paper studies virtual network service provisioning over substrate optical networks and presents a novel reconfiguration scheme to improve efficiency. Simulation results show lower blocking and increased revenues as compared to existing strategies.
    Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference (OFC/NFOEC), 2013; 01/2013
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    ABSTRACT: Cloud computing services are being adopted to expand applications across dispersed data-center sites. As these new paradigms require active data exchange, they impose further virtual network (VN) mappings over operator networks. Now clearly, service recovery after large catastrophic events is a key concern for mission-critical cloud services. Hence in order to address this challenge, this paper presents several post-fault restoration schemes to improve VN survivability based upon partial and full remapping. Detailed simulation analyses are also presented to show the improved efficacy of the restoration approach.
    System of Systems Engineering (SoSE), 2013 8th International Conference on; 01/2013
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    ABSTRACT: Network service recovery from multiple correlated failures is a major concern given the increased level of infrastructure vulnerability to natural disasters, massive power failures, and malicious attacks. To properly address this problem, a novel path protection solution is proposed to jointly incorporate traffic engineering and risk minimization objectives. The framework assumes probabilistic link failures and is evaluated against some existing multi-failure recovery schemes using network simulation.
    IEEE Communications Letters 08/2012; 16(8):1320-1323. · 1.46 Impact Factor
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    ABSTRACT: The advance reservation of network connections is an area of growing interest and a range of service models and algorithms have been proposed to achieve various scheduling objectives, i.e., including optimization-based strategies and heuristic schemes. Now given the time-shifted nature of future requests, rerouting strategies have also been considered to improve resource allocation and carried loads. However, most existing rerouting schemes have focused on minimizing connection disruptions and have not considered further link load information. Along these lines, this paper develops novel rerouting strategies to improve connection scheduling in advance reservation networks. Specifically, a dynamic optimization formulation is presented to handle “on-line” arrivals along with a new heuristic load-balancing strategy. The performance of these proposed solutions is then evaluated for a wide range of network topologies and also compared against some existing rerouting schemes.
    Computer Communications 07/2012; 35(12):1411–1421. · 1.35 Impact Factor
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    Feng Xu, Tamal Das, Min Peng, Nasir Ghani
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    ABSTRACT: Although multi domain survivability is a major concern, few studies have considered post fault restoration schemes. This paper proposes two such strategies (based upon hierarchical routing and signaling crankback) to handle single link failures in multi domain IP/MPLS networks (also extendible to optical DWDM networks). The performance of the proposed solutions is then compared via simulation. I. INTRODUCTION Network survivability is a major issue and pre#planned protection and post#fault restoration schemes have been developed for IP multi protocol label switching (MPLS) and optical generalized MPLS (GMPLS) networks (1). In the former, backup paths are pre#computed and reserved for rapid recovery, i.e., fast switching, whereas in the latter, active re# routing procedures are used to recompute routes after faults. However, most of these strategies have only been applied to single#domain instead of multi domain settings where only selected nodes have partial "global" views due to scalability and confidentiality concerns (2). Although some studies have also looked at multi#domain recovery, most have focused on pre#provisioned protection. For example, (3) and (4) propose sequential/parallel strategies for working/backup routes with improved path diversity, but they are subject to inter#domain "trap" topology or significant routing overheads. Moreover, most multi#domain protection schemes can only perform single#fault recovery. Given the above, it is imperative to study multi#domain post#fault restoration. Even though this approach may yield longer recovery times, it is well#suited to most data services. More importantly, restoration is more resource efficient than protection and can offer a viable "last# gap" alternative in case of multiple failures as part of a tiered survivability framework. Along these lines, two multi#domain restoration schemes are studied here based upon hierarchical routing and signaling crankback strategies. These solutions are presented in Section II and then compared in Section III.
    Optical Switching and Networking. 04/2012; 9:147-155.
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    ABSTRACT: This paper proposes a distributed lightpath protection scheme for diverse routing in multi-domain optical networks with correlated and probabilistic failures. This novel solution jointly considers traffic engineering and failure risk reduction objectives.
  • Mahmoud Ayesh Alayesh, Nasir Ghani
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    ABSTRACT: Power control is a crucial concern in cognitive radio networks where secondary users compete in an opportunistic way to access idle spectrum of primary users. However, most existing studies in this space have only looked at the interactions between secondary users, without considering the impact of primary user behaviors. In this study a novel realistic primary-secondary game-theoretic scheme with a linear pricing function is proposed to obtain a more efficient solution, which rewards primary users for sharing their spectrum to allow secondary users to achieve energy-efficient transmissions. The performance of the proposed realistic power control algorithm with pricing under Rayleigh fast flat fading channels is analyzed, where a closed-form expression is also derived for the average utility function. The existence of a unique Nash equilibrium is also shown and the numerical results are compared to both the realistic power control game model without pricing and to basic additive white Gaussian noise (AWGN) channel model.
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    ABSTRACT: With the increased penetration of real-time systems into our surroundings, the selection of an efficient schedulability test under fixed priority system from a plethora of existing results, has become a matter of primary interest to real-time system designers. The need for a faster schedulability tests becomes more prominent when it applies to online systems, where processor time is a sacred resource and it is of central importance to assign processor to execute tasks instead of determining system schedulability. Under fixed priority nonpreemptive real-time systems, current schedulability tests (in exact form) can be divided into: response time based tests, and scheduling points tests. To the best of our knowledge, no comparative study of these test to date has ever been presented. The aim of this work is to assist the system designers in the process of selecting a suitable technique from the existing literature after knowing the pros and cons associated with these tests. We highlight the mechanism behind the feasibility tests, theoretically and experimentally. Our experimental results show that response time based tests are faster than scheduling points tests, which make the response time based tests an excellent choice for online systems.
    The Journal of Supercomputing 01/2012; 59:1419-1430. · 0.84 Impact Factor

Publication Stats

824 Citations
113.82 Total Impact Points


  • 2008–2014
    • University of New Mexico
      • Department of Electrical and Computer Engineering
      Albuquerque, New Mexico, United States
  • 1970–2014
    • North Dakota State University
      • • Department of Electrical and Computer Engineering
      • • Department of Computer Science
      Fargo, North Dakota, United States
  • 2013
    • University of South Florida
      Tampa, Florida, United States
  • 2010
    • Shanghai Jiao Tong University
      Shanghai, Shanghai Shi, China
  • 2009
    • George Washington University
      Washington, Washington, D.C., United States
    • Massachusetts Institute of Technology
      Cambridge, Massachusetts, United States
  • 2006–2009
    • Indian Institute of Technology Bombay
      • Department of Computer Science & Engineering
      Mumbai, Mahārāshtra, India
  • 2007–2008
    • Institute of Chemical Technology, Mumbai
      Mumbai, Mahārāshtra, India
    • University of Mumbai
      Mumbai, Mahārāshtra, India
    • California Southern University
      Irvine, California, United States
    • National University of Science and Technology
      Islāmābād, Islāmābād, Pakistan
  • 1996–2008
    • University of Waterloo
      • Department of Electrical & Computer Engineering
      Waterloo, Quebec, Canada
  • 2003–2007
    • Tennessee Technological University
      • Department of Electrical and Computer Engineering
      Cookeville, Tennessee, United States
  • 2005–2006
    • Concordia University Montreal
      • Concordia Institute for Information Systems Engineering
      Montréal, Quebec, Canada
    • The University of Western Ontario
      • Department of Electrical and Computer Engineering
      London, Ontario, Canada
  • 2004
    • University of the Western Cape
      Kaapstad, Western Cape, South Africa
    • Lakehead University Thunder Bay Campus
      • Department of Electrical Engineering
      Thunder Bay, Ontario, Canada
  • 1998–2000
    • Nokia Research Center (NRC)
      Helsinki, Southern Finland Province, Finland