Mahmoud Taghizadeh
Michigan State University
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Publication
Featured researches published by Mahmoud Taghizadeh.
IEEE Transactions on Mobile Computing | 2013
Mahmoud Taghizadeh; Kristopher K. Micinski; Subir Biswas; Charles Ofria; Eric Torng
This paper introduces cooperative caching policies for minimizing electronic content provisioning cost in Social Wireless Networks (SWNET). SWNETs are formed by mobile devices, such as data enabled phones, electronic book readers etc., sharing common interests in electronic content, and physically gathering together in public places. Electronic object caching in such SWNETs are shown to be able to reduce the content provisioning cost which depends heavily on the service and pricing dependences among various stakeholders including content providers (CP), network service providers, and End Consumers (EC). Drawing motivation from Amazons Kindle electronic book delivery business, this paper develops practical network, service, and pricing models which are then used for creating two object caching strategies for minimizing content provisioning costs in networks with homogenous and heterogeneous object demands. The paper constructs analytical and simulation models for analyzing the proposed caching strategies in the presence of selfish users that deviate from network-wide cost-optimal policies. It also reports results from an Android phone-based prototype SWNET, validating the presented analytical and simulation results.
IEEE Internet of Things Journal | 2014
Debasmit Banerjee; Bo Dong; Mahmoud Taghizadeh; Subir Biswas
This paper presents a new way of providing privacy for Internet of Things (IoT) in a multi-trust-domain environment. The key idea is to develop a privacy-aware slotted channel access mechanism using which IoT nodes from multiple operators or trust domains can share wireless channel without mutually exposing their identities, thus alleviating threats from cross-trust-domain traffic analysis geared toward node-profiling, link layer topology estimation, node-tracking, and flow-tracking. The proposed scheme uses a novel zero-exposure slot allocation scheme in which packet transmission timing is the only information that is used for scheduling, collision detection, and collision resolution purposes. In addition to the proposed access scheme, this paper reports the design of a custom hardware unit for implementing the proposed protocol in a test-bed of sensors, emulating IoT networks. Presented results include functional validation and performance of the proposed channel access while preventing complete cross-trust-domain identity exposure.
Eurasip Journal on Wireless Communications and Networking | 2011
Muhannad Quwaider; Mahmoud Taghizadeh; Subir Biswas
This paper presents a stochastic modeling framework for store-and-forward packet routing in Wireless Body Area Networks (WBAN) with postural partitioning. A prototype WBANs has been constructed for experimentally characterizing and capturing on-body topology disconnections in the presence of ultrashort range radio links, unpredictable RF attenuation, and human postural mobility. Delay modeling techniques for evaluating single-copy on-body DTN routing protocols are then developed. End-to-end routing delay for a series of protocols including opportunistic, randomized, and two other mechanisms that capture multiscale topological localities in human postural movements have been evaluated. Performance of the analyzed protocols are then evaluated experimentally and via simulation to compare with the results obtained from the developed model. Finally, a mechanism for evaluating the topological importance of individual on-body sensor nodes is developed. It is shown that such information can be used for selectively reducing the on-body sensor-count without substantially sacrificing the packet delivery delay.
IEEE Transactions on Mobile Computing | 2012
Anthony Plummer; Mahmoud Taghizadeh; Subir Biswas
Dynamic Spectrum Access can enable a secondary user in a cognitive network to access unused spectrum, or whitespace, found between primary user transmissions in a wireless network. The key design objective for a secondary user access strategy is to scavenge” the maximum amount of spatio-temporally fragmented whitespace while limiting the amount of disruption caused to the primary users. In this paper, we first measure and analyze the whitespace profiles of an 802.11 network (using ns-2 simulation) and a non-802.11 (CSMA)-based network (developed on TelosB Motes). Then we propose two novel secondary user access strategies, which are based on measurement and statistical modeling of the whitespace as perceived by the secondary users. Afterward, we perform simulation experiments to validate the effectiveness of the proposed access strategies under single and multiple secondary user scenarios, and evaluate their performance numerically using the developed analytical expressions. The results show that the proposed access strategies are able to consistently scavenge between 90 and 96 percent of the available whitespace capacity, while keeping the primary users disruption less than 5 percent.
international conference on computer communications | 2011
Mahmoud Taghizadeh; Amir R. Khakpour; Alex X. Liu; Subir Biswas
Firewalls are one of the essential security elements to enforce access policies in computer networks. Open network architecture, shared wireless medium, stringent resource constraints, and highly dynamic network topology impose a new set of challenges on deploying firewalls in a mobile wireless environment. The current state-of-the-art demands for self protection by personal (i.e. local) firewalls for each node; however, this requires that all unwanted traffic travels all the way to the node before it is discarded at the destination. This wastes considerable bandwidth and power of all of the nodes in a network with multi-hop routing, specially if a node is under a denial of service (DoS) attack. In this paper, we develop a novel distributed firewalling scheme for wireless networks in which nodes collaboratively perform packet filtering to address resource squandering. The proposed scheme introduces techniques to distribute discarding rules based on both proactive and reactive routing protocols. It also proposes efficient rule placement mechanisms to maximize the number of packets discarded remotely before they reach the destination and minimize the number of unwanted packet forwardings. The scheme is evaluated through various simulation scenarios. The simulation results show that by distributing only 1% of the rules, about 42% of the unwanted traffic is discarded before it reaches the destination, which significantly saves the network resources. Saving about 30% of the wasted bandwidth can be crucial for the performance of a wireless network.
ad hoc networks | 2014
Faezeh Hajiaghajani; Yogesh Piolet Thulasidharan; Mahmoud Taghizadeh; Subir Biswas
Abstract Majority of the existing Delay Tolerant Network (DTN) routing protocols attempt to minimize the message delay, forwarding count, or required storage. However, for many DTN applications such as distributing commercial content, targeting the best performance for only one index and neglecting the others is insufficient. A more practical solution would be to strike a balance between multiple of those performance indices. This paper introduces a Gain-aware Dissemination Protocol (GDP) which attempts to reach the maximum economic gain of content delivery by maintaining a balance between the value achieved via message delivery and the involved forwarding costs given out as user rebates. Economic gain from disseminating content is defined as the generated value upon content delivery minus its forwarding costs. The key concept behind the proposed protocol is to adaptively balance between dissemination latency and forwarding costs in order to maximize the economic gain. Using the DTN simulation software ONE, we characterize the GDP protocol with varying mobility models, content sources, and content generation times.
mobile ad hoc networking and computing | 2013
Mahmoud Taghizadeh; Subir Biswas
This paper presents a conceptual framework of social community based cooperative caching for minimizing electronic content provisioning cost in Mobile Social Wireless Networks (MSWNET). Drawing motivation from Amazons Kindle electronic book delivery model, this paper develops practical network, service, and pricing models which are then used for creating an optimal cooperative caching strategy based on social community abstraction in wireless networks.
ad hoc mobile and wireless networks | 2010
Mahmoud Taghizadeh; Francois Dion; Subir Biswas
This paper presents a generalized framework for integrating a wireless network simulator and a vehicle traffic simulator for rapid prototyping and evaluation of Dedicated Short Range Communication (DSRC) based vehicular communication protocols and their applications in the context of Intelligent Transportation System (ITS). A novel method of inter-simulator time synchronization has been designed to simulate the interactions between vehicles and wireless networks at resolutions of up to few tens of milliseconds. This fine grain time synchronization enables the simulation of time-critical ITS safety applications requiring less than 100 ms timing resolutions. The architecture-driven approach that has been adopted further leads to a generalized integration that is agnostic of the specific internal syntaxes used by the individual communication network and vehicle simulators that are being integrated. As a feasibility demonstration, the framework is used to integrate Paramics, a vehicular traffic simulator, with ns-2, a communication network simulator. The resulting integrated simulator is then utilized to investigate the performance of wireless message propagation in the context of a freeway car collision avoidance application.
mobile adhoc and sensor systems | 2010
Mahmoud Taghizadeh; Anthony Plummer; Subir Biswas
This paper presents a cooperative object caching mechanism for maintaining high content availability in Social Wireless Networks. Most of the existing cooperative caching schemes in wireless networks provide either high network level availability or high node level availability, but not both at the same time. The first one ensures object availability in isolated network partitions and the second one ensures object availability in individual nodes when they are completely detached from the rest of the network. In this paper, we propose a novel cache partitioning mechanism that is able to provide high network level and high node level availabilities at the same time. This scheme reduces the generated network traffic compared to the prevalent schemes in the literature. In addition to computing theoretical bounds for the availabilities and generated traffic, caching performance is evaluated using a detailed ns2 simulation model under static and mobile networks with realistic mobility patterns.
communication systems and networks | 2014
Debasmit Banerjee; Bo Dong; Subir Biswas; Mahmoud Taghizadeh
This paper proposes a novel wireless MAC-layer approach towards achieving channel access anonymity. Nodes autonomously select periodic TDMA-like time-slots for channel access by employing a novel channel sensing strategy, and they do so without explicitly sharing any identity information with other nodes in the network. An add-on hardware module for the proposed channel sensing has been developed and the proposed protocol has been implemented in Tinyos-2.x. Extensive evaluation has been done on a test-bed consisting of Mica2 hardware, where we have studied the protocols functionality and convergence characteristics. The functionality results collected at a sniffer node using RSSI traces validate the syntax and semantics of the protocol. Experimentally evaluated convergence characteristics from the Tinyos test-bed were also found to be satisfactory.