@conference {
	title = {Tuning the TCP Timeout Mechanism in Wireless Networks to Maximize Throughput via Stochastic Stopping Time Methods},
	author = {Papageorgiou, George., Baras, John S.},
	year = {2010},
	month = {07/2010},
	abstract = {We present an optimization problem that aims to maximize the throughput of a Transmission Control Protocol (TCP) connection between two nodes in a wireless adhoc network. More specifically, we focus on a persistent TCP connection between two nodes that are one hop away in a wireless unslotted Aloha network. The optimization is over the TCP timeout period, i.e. the problem is to find the optimal waiting period before the TCP sender declares a timeout event in the absence of a received acknowledgement for a transmitted packet. The problem is formulated as an optimal stochastic stopping time problem. In the absence of a tractable analytical solution to the problem, a numerical method based on dynamic programming is used instead. We verify the performance increase by comparing our solution to the standard TCP timeout mechanism using simulations for a range of values of the involved parameters.},
	address = {Budapest, Hungary},
	booktitle = {The 19th International Symposium on Mathematical Theory of Networks and Systems (MTNS 2010)},
	pages = {pp. 1539-1545}
}
@conference {
	title = {Performance Metric Sensitivity Computation for Optimization and Trade-off Analysis in Wireless Networks},
	author = {Baras, John S., Tabatabaee, Vahid., Papageorgiou, George., Rentz, Nicolas.},
	year = {2008},
	month = {11/2008},
	abstract = {We develop and evaluate a new method for estimating and optimizing various performance metrics for multihop wireless networks, including MANETs. We introduce an approximate (throughput) loss model that couples the physical, MAC and routing layers effects. The model provides quantitative statistical relations between the loss parameters that are used to characterize multiuser interference and physical path conditions on the one hand and the traffic rates between origin-destination pairs on the other. The model takes into account effects of the hidden nodes, scheduling algorithms, IEEE 802.11 MAC and PHY layer transmission failures and finite packet transmission retries at the MAC layer in arbitrary network topologies where multiple paths share nodes. We apply Automatic Differentiation (AD) to these implicit performance models, and develop a methodology for sensitivity analysis, parameter optimization and trade-off analysis for key wireless protocols. Finally, we provide simulation experiments to evaluate the effectiveness and performance estimation accuracy of the proposed models and methodologies.},
	address = {New Orleans, LA},
	booktitle = {IEEE Global Communications Conference (IEEE Globecom 2008)},
	pages = {pp. 1-5}
}
@conference {
	title = {Modelling and Optimization for Multi-hop Wireless Networks Using Fixed Point and Automatic Differentiation},
	author = {Baras, John S., Tabatabaee, Vahid., Papageorgiou, George., Rentz, Nicolas.},
	year = {2008},
	month = {03/2008},
	abstract = {We develop and evaluate a new method for estimating and optimizing various performance metrics of multi-hop wireless networks, including MANETs. We introduce a simple approximate (throughput) loss model that couples the physical, MAC and routing layers effects. The model provides quantitative statistical relations between the loss parameters that are used to characterize multiuser interference and physical path conditions on the one hand and the traffic rates between origin-destination pairs on the other. The model considers effects of the hidden nodes, node scheduling algorithms, MAC and PHY layer failures and unsuccessful packet transmission attempts at the MAC layer in arbitrary network topologies where multiple paths share nodes. We apply Automatic Differentiation (AD) to these implicit performance models~and develop a methodology for sensitivity analysis and parameter optimization for wireless protocols. Finally, we provide simulation experiments to evaluate the effectiveness and performance estimation accuracy of the proposed models and methodologies.},
	address = {Berlin, Germany},
	booktitle = {6th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt{\textquoteright}08)},
	pages = {pp.  295 -300}
}
@conference {
	title = {Loss Model Approximations and Sensitivity Computations for Multi-Hop Wireless Network Design},
	author = {Baras, John S., Tabatabaee, Vahid., Papageorgiou, George., Rentz, Nicolas., Shang, Yadong.},
	year = {2007},
	month = {10/2007},
	abstract = {We develop and evaluate a new method for estimating various performance metrics of multi-hop wireless networks, including MANETs. The estimates depend implicitly on network design parameters, and therefore the method can form the basis for designing such networks so as to achieve predictable performance bounds. Explicit simulation models for large wireless networks are too complex and can not be used for analysis and design of wireless networks in realistic settings. We introduce a simple approximate (throughput) loss model that couples the physical, MAC and routing layers. The model provides quantitative statistical relations between the loss parameters used to characterize multiuser interference and physical path conditions on the one hand and traffic rates between origin-destination pairs on the other. We use a fixed point approach together with recently proposed models for the MAC layer to find a consistent solution satisfying all equations in the set. The result is an implicit model of performance metrics, such as throughput, packet loss, delay, parameterized by design variables, such as path routing probabilities, power levels, noise levels. We next apply Automatic Differentiation (AD) to these implicit performance models and develop a methodology for design and parameter selection/tuning of wireless protocols.},
	address = {Orlando, FL},
	booktitle = {2007 Military Communication Conference},
	pages = {pp. 1-7}
}
@conference {
	title = {Performance Evaluation and Traffic Analysis for Routing Protocols in a Real MANET},
	author = {Chen, Huigang., Jou,  Jia-Shiang., Dharmaraju, Dinesh., Papageorgiou, George., Baras, John S.},
	year = {2003},
	month = {04/2003},
	abstract = {Mobile Ad-hoc NETworks (MANETs) are characterized by bandwidth constrained links, multiple hops, varying link qualities and highly dynamic topologies. In this paper, we evaluate the performance and analyze the traffic of a mobile ad-hoc network in a realistic setting. Using simulation, we provide results of performance evaluation in terms of various metrics. We study performance with scenarios of different propagation matrices, different traffic mixes, and different routing protocols (DSDV, DSR, AODV). The results show that in most cases, the performance is sensitive to the routing protocol, path loss, and traffic characteristics. This provides rationale and insight for choosing the right protocols to provide quality of service in terms of different metrics in different environments. Also, we find that in a MANET, we obtain long-range dependency traffic regardless of source file size distribution. This discovery will help in providing methodology to tackle the network dimensioning problem in ad hoc networks.},
	address = {College Park, Maryland},
	booktitle = {Collaborative Technology Alliances (CTA) Communications \&amp; Networks (C\&amp;N) Alliance - 2003 Annual Symposium},
	pages = {pp.147-151},
	organization = {University of Maryland Conference Center}
}
