Abstract:

Severe delay and resource (energy, bandwidth) constraints are typical in emerging communications and networking applications within a variety of scientific and engineering disciplines. This is particularly the case in highly constrained sensor networks. Such applications strongly motivate foregoing the convenience of digital communication and revisiting the potential benefits, and even necessity of analog communication, albeit in the modern context of distributed source-channel coding. In the first part of the talk, I will present the major challenges and my research efforts in analog networking, i.e., zero delay source-channel coding, including the derivation of a theoretical foundation from estimation and information theoretic principles, developing effective practical algorithmic approaches and the analysis of the fundamental limits. In digital communications, "structured" codes, such as linear, lattice codes etc., are commonly used. Fortunately, these structured codes can achieve the fundamental limits, i.e., structure comes free. In resource constrained communications,  this is not the case in general. I will present the necessary and sufficient conditions for the optimal zero-delay encoding and decoding mappings to have structure. A particular focus will be on the conditions for linearity of optimal estimation and their implications. 

Analog networking is intrinsically connected to stochastic control. The theoretical results obtained  from analog networking shed light on the stochastic control problems and some numerical approaches are directly applicable in open control problems as well. As an example, I will present a numerical solution, based on the ideas developed to solve analog networking problems, to Witsenhausen's counter-example, a well known open problem in decentralized control.  Potential applications of the basic ideas in broad stochastic networked control systems will also be discussed.


Bio:

Emrah Akyol received the B.Sc. degree in 2003 from Bilkent University, the M.Sc. degree in 2005 from Koc University (both in Turkey), and the Ph.D. degree in 2011 in electrical and computer engineering from UC Santa Barbara. From 2005 to 2007, he held positions at Hewlett-Packard Laboratories and NTT Docomo Laboratories (both in Palo Alto, CA) where he worked on several topics in multimedia compression and networking.

Currently, Dr. Akyol is a postdoctoral researcher at UC Santa Barbara. His research focuses on source coding, joint source-channel coding, energy efficient communications.