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Events for February 23, 2011
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EE-Electrophysics Seminar
Wed, Feb 23, 2011 @ 10:00 AM - 11:00 AM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Gianluca Piazza, University of Pennsylvania, Department of Electrical and Systems Engineering
Talk Title: AlN Piezoelectric NanoElectroMechanical Resonators and Switches for RF Signal Processing, Sensing and Computing
Abstract: NanoElectroMechanical Systems (NEMS) resonators and switches have been identified as some of the most interesting technologies that will enable the More Moore and More than Moore evolution of the semiconductor industry. These NEMS devices will yield transformational improvements over state-of-the-art semiconductor-based products by decreasing power consumption, increasing frequencies of operation and increasing sensing resolution â which will revolutionize computing, chemical/biological sensing, and radio frequency (RF) and microwave communication.
A major challenge for developing NEMS based technology is the ability to efficiently transduce the mechanical device at the chip scale. This talk presents remarkable opportunities associated with the scaling of piezoelectric AlN films to the nano realm and their application to the making of efficient NEMS resonators and switches that can be directly interfaced with conventional electronics.
Experimental data showing NEMS AlN resonators (250 nm thick with lateral features as small as 300 nm) vibrating at record-high frequencies approaching 10 GHz with Qs in excess of 500 will be presented. The extremely compact form factor of these devices permits to envision large scale integration (LSI) of NEMS to develop low power and highly reconfigurable microwave radio transceivers. Similarly, experimental results will show how these NEMS resonators can yield unprecedented sensitivities and be employed to form miniaturized gas sensor arrays and tag gas analyte concentrations that reach the part per trillion levels.
Finally, nano-piezoelectric films (50-100 nm thick) for switching applications and experimental data confirming that bimorph AlN nano-piezo-actuators achieve the same piezoelectric properties of microscale counterparts will be presented. These NEMS devices set a realistic pathway towards the development of low energy nanomechanical computing.
Biography: Gianluca Piazza is a Wilf Family Term Assistant Professor in the department of Electrical and Systems Engineering (ESE) at the University of Pennsylvania. His research interests focus on piezoelectric micro and nano electromechanicalsystems (MEMS/NEMS) for RF wireless communications, chemical/biological detection, and all mechanical computing. He also has a general interest in the areas of micro/nano fabrication techniques and integration of micro/nano devices with state-of-the-art electronics. He received his Ph.D. degree from the University of California, Berkeley in 2005. He has more than 10 years of experience working with piezoelectric materials. He holds several patents in the field of micromechanical resonators some of which have been succesfully acquired by industry (IDT and Qualcomm). He received the IBM Young Faculty Award in 2006 and has won, with his students, the Best Paper Award in Group 1 and 2 at the IEEE Frequency Control Symposium in 2008 and 2009, respectively.
Host: EE-Electrophysics
More Info: http://ee.usc.edu/news/seminars/eepLocation: Seaver Science Library (SSL) - 150
Audiences: Everyone Is Invited
Contact: Marilyn Poplawski
Event Link: http://ee.usc.edu/news/seminars/eep
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PhD Defense - Optimal Resource Allocation and Cross-Layer Control in Cognitive and Cooperative Wireless Networks
Wed, Feb 23, 2011 @ 10:30 AM - 11:30 AM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Rahul Urgaonkar, USC PhD Candidate
Talk Title: PhD Defense - Optimal Resource Allocation and Cross-Layer Control in Cognitive and Cooperative Wireless Networks
Abstract: Next generation wireless networks will be required to provide significantly higher data rates, reliability, and energy efficiency than the existing systems. Cognitive radio and cooperative communication are expected to be two essential technologies towards achieving this goal. In this thesis, we study several resource allocation problems in the area of cognitive and cooperative wireless networks. Our goal is to design optimal control algorithms that maximize time-average network utilities (such as throughput) subject to time-average constraints (such as power, reliability, etc.). This talk will present our work on two such problems.
The first problem considers opportunistic cooperation in cognitive radio networks. Specifically, we assume that a secondary user can use its resources to improve the transmission rates of the primary user. In return, the secondary user can get more opportunities for transmitting its own data when the primary user is idle. In this scenario, it is important for the secondary user to balance the desire to cooperate more (to create more transmission opportunities) with the need for maintaining sufficient energy levels for its own transmissions. Such a model is applicable in the emerging area of cognitive femtocell networks. We formulate the problem of maximizing the secondary user throughput subject to a time average power constraint under these settings as a constrained Markov Decision Problem. Conventional solution techniques to this problem are based on dynamic programming and require either extensive knowledge of the system dynamics or learning based approaches that suffer from large convergence times. However, using the technique of Lyapunov optimization, we design a novel greedy and online control algorithm that does not require any knowledge of network dynamics or explicit learning, yet is optimal.
The second problem investigates optimal routing and scheduling strategies for multi-hop wireless networks with rateless codes. Rateless codes allow each node of the network to accumulate mutual information with every packet transmission. This enables a significant performance gain over conventional shortest path routing. Further, it also outperforms cooperative communication techniques that are based on energy accumulation. However, it requires complex and combinatorial networking decisions concerning which nodes participate in transmission, and which decode ordering to use. We formulate the general problem as a combinatorial optimization problem and then make use of several structural properties to simplify the solution and derive optimal greedy algorithms. A key feature of these algorithms is that unlike prior works on these problems, they do not require solving any linear programs to compute the optimal solution.
Biography: Rahul Urgaonkar obtained the B.Tech. degree in Electrical Engineering from the Indian Institute of Technology (IIT) Bombay in 2002 and the M.S. degree in Electrical Engineering from the University of Southern California, Los Angeles in 2005. He is currently a PhD candidate in Electrical Engineering at USC working with Prof. Michael Neely. His research interest is in the area of stochastic network optimization with applications to resource allocation and scheduling problems in next generation wireless networks and data centers.
Host: Prof. Michael J. Neely
Location: Hughes Aircraft Electrical Engineering Center (EEB) - 539
Audiences: Everyone Is Invited
Contact: Gerrielyn Ramos
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Channel Coding: Non-Asymptotic Fundamental Limits With and Without Feedback
Wed, Feb 23, 2011 @ 02:00 PM - 03:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
University Calendar
Abstract: Information theory studies the question of the maximum possible rate achievable by an ideal system under certain assumptions regarding the noise generation and structural design constraints. The study of such questions, initiated by Claude Shannon in 1948, has typically been carried out in the asymptotic limit of an infinite number of signaling degrees of freedom (blocklength). However, with the ever increasing demand for ubiquitous access to real time data, such as audio and video streaming for mobile devices, as well as the advent of modern sparse graph codes, one is interested in describing fundamental limits non-asymptotically, i.e. for blocklengths of the order of 1000. By employing some of our recently developed methods it will be demonstrated that for such blocklengths the backoff from the capacity can be quite significant. On the other hand, this penalty can be considerably mitigated by employing variable-length codes with feedback.
Biography: Yury Polyanskiy received the M.S. degree (with honors) in applied mathematics and physics from the Moscow Institute of Physics and Technology, Moscow, Russia in 2005 and the Ph.D. degree in electrical engineering from Princeton University, Princeton, NJ in 2010.
In 2000-2005, he was with the Department of Surface Oilfield Equipment, Borets Company LLC, where he rose to the position of Chief Software Designer. His research interests include information theory, coding theory and the theory of random processes.
Dr. Polyanskiy won a silver medal at the 30th International Physics Olympiad (IPhO), held in Padova, Italy. He was a recipient of the Best Student Paper Awards at the 2008 and 2010 IEEE International Symposia on Information Theory (ISIT). His final year of graduate studies was supported by a Princeton University Honorific Dodds Fellowship (2009-2010).
Host: Alex Dimakis, dimakis@usc.edu and Urbashi Mitra, ubli@usc.eduLocation: Hughes Aircraft Electrical Engineering Center (EEB) - 248
Audiences: Everyone Is Invited
Contact: Gerrielyn Ramos
