@conference {
	title = {Efficient and Robust Communication Topologies for Distributed Decision Making in Networked Systems},
	author = {Baras, John S., Hovareshti, Pedram.},
	year = {2009},
	month = {12/2009},
	abstract = {Distributed decision making in networked systems depends critically on the timely availability of critical fresh information. Performance of networked systems, from the perspective of achieving goals and objectives in a timely and efficient manner is constrained by their collaboration and communication structures and their interplay with the networked system{\textquoteright}s dynamics. In most cases achieving the system objectives requires many agent to agent communications. A reasonable measure for system robustness to communication topology change is the number of spanning trees in the graph abstraction of the communication system. We address the problem of network formation with robustness and connectivity constraints. Solutions to this problem have also applications in trust and the relationship of trust to control. We show that the general combinatorial problem can be relaxed to a convex optimization problem. We solve the special case of adding a shortcut to a given structure and provide insights for derivation of heuristics for the general case. We also analyze the small world effect in the context of abrupt increases in the number of spanning trees as a result of adding a few shortcuts to a base lattice in the Watts-Strogatz framework and thereby relate efficient topologies to small world and expander graphs.},
	address = {Shanghai, China},
	booktitle = {48th IEEE Conference on Decision and Control},
	pages = {pp. 3751-3756}
}
@conference {
	title = {Dynamic Self-Organization and Clustering in Distributed Networked Systems for Performance Improvement},
	author = {Baras, John S., Hovareshti, Pedram., Perumal, Senni.},
	year = {2009},
	month = {09/2009},
	abstract = {We consider two closely related dynamic self-organization problems in networked control systems. Both are forms of the~dynamic clustering of nodes. The structure of networked control systems is often abstracted using graph theory. In this abstraction, the nodes of the graph represent the agents and the edges between them represent the relation(s) or the possibility of communication between the corresponding agents. The topology of the communication network supporting a networked control system has critical consequences for its performance. The first problem we address is the development of a distributed self-organization algorithm, resulting into a dynamic two level hierarchy of leader and regular agents, which substantially improves the convergence speed of distributed algorithms utilized by the networked control system. For the second problem, we consider the collaborative control of a group of autonomous mobile agents (e.g. vehicles, robots) supported by a mobile wireless network, consisting of many grounds and a few aerial nodes. The agents collaborate to achieve a common goal or objective, like to move in a particular area and cover it, while avoiding obstacles and collisions. Building upon our earlier work on deterministic, randomized and hybrid distributed coordination algorithms we consider the communication needs of the agents, and in particular, the connectivity of their communication network as they move. We develop distributed algorithms that automatically select some agents and move them appropriately so as to maintain a~certain degree of desired connectivity among the moving agents. We characterize the trade-off between the gain from maintaining a certain degree of connectivity vs. the combined cost of communications and the associated dynamic re-positioning of agents. We also describe classes of efficient communication topologies and in particular their similarity to dynamic small-world topologies and extensions.},
	address = {Montecello, Illinois},
	booktitle = {Forty-Seventh Annual Allerton Conference on Communication, Control, and Computing (Allerton Conference 2009)},
	pages = {pp. 968-975},
	organization = {University of Illinois at Urbana-Champaign}
}
@conference {
	title = {Coalition Formation and Trust in Collaborative Control},
	author = {Baras, John S., Jiang, Tao., Hovareshti, Pedram.},
	year = {2009},
	month = {08/2009},
	abstract = {We consider the collaboration of autonomous agents as a coalitional game subject to constraints, like communication, trust or reputation. We analyze the tradeoff between the benefits of collaboration and these constraints (or costs of collaboration) via dynamic, iterative stochastic games. The agents can observe locally the actions of other agents in their neighborhood and decide whether to collaborate or not in a distributed asynchronous manner. Trust values are taken into consideration when agents act and collaborate. Specifically they affect the selection of agents to collaborate with. We consider only problems where the information used for either estimating reputations or deciding on strategies is mostly local; i.e. from the neighbors of each agent. We show that randomized algorithms emerge as the agents try to reach the maximum payoff. We also investigate the topology of the formed network by studying the second largest eigenvalue of the corresponding graph, and describe its effects on control performance.},
	address = {Budapest, Hungary},
	booktitle = {European Control Conference 2009 (ECC {\textquoteright}09)},
	pages = {pp.1197-1202}
}
@conference {
	title = {Event Triggered Distributed Collaborative Control},
	author = {Baras, John S., Hovareshti, Pedram., Perumal, Senni.},
	year = {2009},
	month = {08/2009},
	abstract = {We consider the collaborative control of a group of autonomous mobile agents (e.g. vehicles, robots). The agents collaborate to achieve a common goal or objective, like to move in a particular area and cover it, while avoiding obstacles and collisions. Building upon our earlier work on deterministic, randomized and hybrid distributed coordination algorithms we consider the communication needs of the agents, and in particular, the connectivity of their communication network as they move. We develop algorithms that automatically sense the possibility or inset of loss of connectivity among the agents. We also consider the automatic detection of path disconnection when more than one paths need to be maintained between pairs of agents. Using local probing schemes we formulate such problems as event-triggered control problems. We develop distributed algorithms that automatically select some agents and move them appropriately so as to maintain a~certain degree of desired connectivity among the moving agents. We characterize the trade-off between the gain from maintaining a certain degree of connectivity vs the combined cost of communications and the associated dynamic re-positioning of agents. The results illustrate the efficiency achieved by the~event-triggered control in such problems. We also describe the resulting communication topologies and in particular their similarity to dynamic small-world topologies.},
	address = {Budapest, Hungary},
	booktitle = {European Control Conference 2009 (ECC {\textquoteright}09)},
	pages = {pp.3797-3802}
}
