@conference {
	title = {Distributed Medium Access and Opportunistic Scheduling for Ad-Hoc Networks: An Analysis of the Constant Access Time Problem},
	author = {Chen, Hua., Hovareshti, Pedram., Baras, John S.},
	year = {2011},
	month = {12/2011},
	abstract = {In this paper, we study the problem of medium access and distributed opportunistic scheduling to exploit channel fluctuations for wireless ad-hoc networks. This work focuses on the Constant Access Time (CAT) problem, where the total time duration of channel probing and data transmission is slotted into fixed block length. In particular, we consider the dependence between channel rates at different time instances during the channel probing phase and its impact on the overall system throughput. We first analyze the system performance of the CAT problem under independent channel rate assumption and compare our result to the existing work on the Constant Data Time (CDT) problem. We then propose a protocol to reduce the channel probing costs based on this analysis. We show analytical results of the proposed protocol for systems with a sufficiently large number of users. We compare the system performance of the proposed protocol with that of the original protocol under independent channel rate assumption. We mathematically prove that the proposed protocol improves the system performance.},
	address = {Houston Texas},
	booktitle = {IEEE Globecom 2011},
	pages = {pp. 1-6}
}
@conference {
	title = {Communication Network Challenges for Collaborative Vehicles},
	author = {Chen, Hua., Hovareshti, Pedram., Baras, John S.},
	year = {2011},
	month = {11/2011},
	abstract = {Networked systems of autonomous mobile agents have emerged in a variety of applications such as collaborative robotics, unmanned aerial/ground vehicles, mobile sensor networks and disaster relief operations. These agents utilize wireless communications for distributed computing, control and decision-making. Due to their limitations on energy supply, design and implementation of efficient distributed algorithms are crucial for these systems. This paper reviews different design aspects of networks of collaborative vehicles. We survey existing methods of addressing physical (PHY) and medium access control (MAC) layer, routing, and geometric connectivity issues for such networks and show limitations of these designs that address only single layer issues. We argue that a system engineering framework is needed for the design of such systems.},
	address = {Pacific Grove CA},
	booktitle = {Asilomar Conference on Signals, Systems, and Computers},
	pages = {pp. 1472-1476}
}
@conference {
	title = {Motif-based Topology Design for Effective Performance by Networks of Mobile Autonomous Vehicles},
	author = {Hovareshti, Pedram., Chen, Hua., Baras, John S.},
	year = {2011},
	month = {06/2011},
	abstract = {To design efficient local connectivity patterns, we have used the idea of network motifs, which was first proposed in the context of biological networks. Network motifs are task specific local connectivity patterns, which exist with much higher frequency in real biological networks compared to those in random networks. These are sub-networks of a low number of nodes (usually 3-4) whose persistence in networks performing similar tasks in different contexts, imply their efficiency in the sense that they optimize certain performance metric in a local scale. We use a simulation test bed to find network motifs for local level communication structures in a collaborative vehicles framework. Here, the group mission consists of several tasks that the agents participate in. The tasks include search operation, data gathering/processing, target finding and leader-follower explorations. Each task gives rise to certain motifs that are specific to that task and the partial knowledge of the environment specifications that the agents operate in. In this way, given the subtasks that are necessary for the mission accomplishment, the most efficient task-specific local topologies are extracted. Switching suitable graphs when the mode of operation is changing can be handled by solving the resulting reachability problem using methods for symbolic planning such as graph grammars. Based on such switching, we also address the effects of split/merge operations on the spectral characteristics of the resulting connectivity graphs.},
	address = {Quincy, MA},
	booktitle = {Eighth International Conference on Complex Systems (ICCS 2011),},
	pages = {pp.  571-573}
}
