21st Nov 2013

STOR-i Seminar- Natarajan Gautam

14:00-15:00, A54 PSC

Multi-timescale Model for Wireless Nodes Powered by Renewable Energy Sources

with Natarajan Gautam, Texas A&M University


Abstract: We consider a node in a multi-hop wireless network that is responsible for transmitting messages in a timely manner while being prudent about energy consumption. The node is powered by batteries that are charged by renewable energy sources such as wind or solar. To strike a balance between latency and availability, we consider a multi-timescale model. At a faster timescale, the node makes decisions based on local information such as queue lengths of packets in input buffers and available energy levels. The decisions include scheduling packets on the output buffers that would be transmitted at the next opportunity. At the slower timescale we model the energy levels in the battery using a stochastic fluid-flow model to determine the availability. Ultimately we present a unified framework that iteratively sets model parameters to satisfy latency and availability targets. The methods are based on Markov decision processes, Markov chains and semi-Markov process analysis.


Biosketch: N. Gautam is an associate professor and Jill and Charles F. Milstead `60 Faculty fellow in Industrial and Systems Engineering at Texas A&M University. He holds a courtesy appointment in the department of Electrical and Computer Engineering. Prior to joining Texas A&M University in 2005, he was on the Industrial Engineering faculty at Penn State University for eight years. He received his Ph.D. and M.S. in Operations Research from the University of North Carolina at Chapel Hill, and his B.Tech. in Mechanical Engineering from Indian Institute of Technology, Madras. Gautam's interests are in optimal design, control and performance evaluation of stochastic systems, with an emphasis on computer networks, energy and biology. He directs the Group for Research on Engineering ENergy-efficiency (GREEN) housed in the Laboratory for Energy-Sustainable Operations. Gautam's research articles have appeared in journals published by INFORMS, IIE, IEEE and ACM. He has worked on multi-disciplinary projects funded by NSF, AFOSR, DARPA, ONR and U.S. Marine Corps. Gautam received the Outstanding Young Industrial Engineer Award (education category) bestowed by IIE in 2006. In addition, he has won a few teaching awards and best paper awards. He published a book in 2012 -- Analysis of Queues: Methods and Applications. Gautam serves as an associate editor for IIE Transactions, INFORMS Journal on Computing and OMEGA.

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