@conference {
	title = {A Coalitional Game Based Approach for Multi-Metric Optimal Routing in Wireless Networks},
	author = {Stai, Eleni., Papavassiliou, Symeon., Baras, John S.},
	year = {2013},
	month = {09/2013},
	abstract = {Future communications consist of an increasing number of wireless parts, while simultaneously need to support the widespread multimedia applications imposed by social networks. These human-machine systems, driven by both real time social interactions and the challenges of the wireless networks{\textquoteright} design, call for efficient and easy to implement, distributed cross-layer algorithms for their operation. Performance metrics such as throughput, delay, trust, energy consumption, need to be improved and optimized aiming at high quality communications. We investigate the coveted throughput-delay trade-off in static wireless multihop networks based on a {\textquotedblleft}computer-aided{\textquotedblright} design of the backpressure scheduling/routing algorithm for networks embedded in hyperbolic space. Both routing and scheduling exploit the hyperbolic distances to orient the packets to the destination and prioritize the transmissions correspondingly. The proposed design provides us with the freedom of controlling its theoretical throughput optimality and of counterbalancing its practical performance through simulations, leading to significant improvements of the throughput-delay trade-off.},
	address = {London, UK},
	booktitle = {Proceedings of IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications: Mobile and Wireless Networks},
	pages = {pp. 1935-1939}
}
@conference {
	title = {Social Networks over Wireless Networks},
	author = {Stai, Eleni., Baras, John S., Papavassiliou, Symeon.},
	year = {2012},
	month = {12/2012},
	abstract = {We consider the formation, operation and maintenance of dynamic social networks (among human users) supported by technological communication networks such as wireless networks, or hybrid wireline-wireless networks. The technological (physical) networks of interest display dynamic behavior in several dimensions, including variable connectivity, variable congestion, variable link characteristics. As broadband wireless devices and networks are becoming ubiquitous these human-machine systems, that combine the social aspects and behavioral activities of humans with the technological characteristics of the underlying physical networks, provide several important challenges in efforts to model them, evaluate their performance and dynamically control them so certain performance requirements are met. These include combinations of performance, trust, privacy, energy efficiency. In this paper we develop novel models for these complex human-machine systems that incorporate social network behavioral models and wireless network models that are inspired from statistical physics (hyperbolic graphs). We investigate the performance of wireless network protocols that support and respond to the constraints implied by the social network they support.},
	address = {Maui, Hawaii},
	booktitle = {51st IEEE Conference on Decision and Control},
	pages = {pp. 2696-2703}
}
@conference {
	title = {A Class of Backpressure Algorithms for Networks Embedded in Hyperbolic Space with Controllable Delay-Throughput Trade-off},
	author = {Stai, Eleni., Baras, John S., Papavassiliou, Symeon.},
	year = {2012},
	month = {10/2012},
	abstract = {Future communications consist of an increasing number of wireless parts, while simultaneously need to support the widespread multimedia applications imposed by social networks. These human-machine systems, driven by both real time social interactions and the challenges of the wireless networks~design, call for efficient and easy to implement, distributed cross-layer algorithms for their operation. Performance metrics such as throughput, delay, trust, energy consumption, need to be improved and optimized aiming at high quality communications. We investigate the coveted throughput-delay trade-off in static wireless multihop net- works based on a {\textquotedblleft}computer-aided{\textquotedblright} design of the backpressure scheduling/routing algorithm for networks embedded in hyperbolic space. Both routing and scheduling exploit the hyperbolic distances to orient the packets to the destination and prioritize the transmissions correspondingly. The proposed design provides us with the freedom of controlling its theoretical throughput optimality and of counterbalancing its practical performance through simulations, leading to significant improvements of the throughput-delay trade-off.},
	address = {Paphos, Cyprus Island},
	booktitle = {15th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM 2012), pp. no. 15-22, Paphos, Cyprus Island},
	pages = {pp. 15-22}
}
@conference {
	title = {Throughput-Delay Trade-off in Wireless Multi-hop Networks via Greedy Hyperbolic Embedding},
	author = {Stai, Eleni., Baras, John S., Papavassiliou, Symeon.},
	year = {2012},
	month = {07/2012},
	abstract = {Real time applications over wireless multihop networks, demand routing/scheduling algorithms that achieve desirable delay-throughput trade-offs, with high throughput and low end-to-end delay. The backpressure algorithm, has received much attention by the research community in the past few years, as it satisfies the throughput optimal requirement. The backpressure algorithm performs routing and scheduling based on congestion gradients, by allowing transmission to the links that maximize the differential backlog between neighboring nodes. However, by deploying routing without using any information about the position or distance to the destination, it explores all possible source-destination paths leading to undesirable high delays. In this paper, we propose a method of restricting the number of paths used by the backpressure algorithm, with the aid of the greedy embedding of a network in the hyperbolic space. We propose two algorithms, the {\textquotedblleft}Greedy{\textquotedblright} backpressure and the {\textquotedblleft}Greediest{\textquotedblright} backpressure for both static and dynamic networks, which consider the network embedded in the hyperbolic space and combine the greedy routing in hyperbolic coordinates with the backpressure scheduling. We prove analytically their throughput optimality and study through simulations the induced improvement in the delay-throughput trade-off compared with the backpressure algorithm.},
	address = {Melbourne, Australia},
	booktitle = {20th International Symposium on Mathematical Theory of Networks and Systems (MTNS 2012)},
	pages = {pp. 1-8}
}
@article {
	title = {Performance-Aware Cross-layer Design in Wireless Multihop Networks via a Weighted Backpressure Approach},
	author = {Stai, Eleni., Papavassiliou, Symeon., Baras, John S.},
	year = {2016},
	month = {02/2016},
	abstract = {In this paper, we study, analyze, and evaluate a performance-aware cross-layer design approach for wireless multihop networks. Through network utility maximization (NUM) and weighted network graph modeling, a cross-layer algorithm for performing jointly routing, scheduling, and congestion control is introduced. The performance awareness is achieved by both the appropriate definition of the link weights for the corresponding application{\textquoteright}s requirements and the introduction of a weighted backpressure (BP) routing/scheduling. Contrary to the conventional BP, the proposed algorithm scales the congestion gradients with the appropriately defined per-pair (link, destination) weights. We analytically prove the queue stability achieved by the proposed cross-layer scheme, while its convergence to a close neighborhood of the optimal source rates{\textquoteright} values is proven via an epslon-subgradient approach. The issue of the weights{\textquoteright} assignment based on various quality-of-service (QoS) metrics is also investigated. Through modeling and simulation, we demonstrate the performance improvements that can be achieved by the proposed approach{\textemdash}when compared against existing methodologies in the literature{\textemdash}for two different examples with diverse application requirements, emphasizing respectively on delay and trustworthiness.},
	pages = {pp. 245-258},
	volume = {Vol. 24},
	number = {Issue 1},
	journal = {IEEE ACM Transactions on Networking}
}
