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ALI H. SAYED | Professor and Chairman
Electrical Engineering
Overview of Electrical Engineering Department
Ali H. Sayed is Professor and Chairman of Electrical Engineering at UCLA, where he founded and directs the Adaptive Systems Laboratory. He is a Fellow of the IEEE for his contributions to adaptive filtering and estimation algorithms. His research has attracted several recognitions and awards. He has published 5 books and over 300 articles.
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AJEY JACOB |
Intel
Overview of Western Institute of Nanoelectronics (WIN)
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DANIEL SOLI | Postdoctoral Fellow
Electrical Engineering
Optical Rogue Waves
Maritime folklore tells tales of giant rogue waves that can appear and
disappear without warning in the open ocean. Now, we have discovered optical rogue wavesfreak brief pulses of intense light analogous to the infamous oceanic monsterspropagating through optical fiber.
Daniel Soli is a postdoctoral fellow in the Electrical Engineering Department at
UCLA, and recently received the UCLA Chancellor's Award for Postdoctoral Research. His recent work on optical rogue waves was published in the journal Nature, and was widely covered by the news media. His research interests include optical rogue waves, supercontinuum generation, real-time spectroscopy, silicon photonics, and biophotonics. He holds a Ph.D. in physics from UC Berkeley.
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SHERVIN MOLOUDI |
Electrical Engineering
An outphasing Power Amplifier for a Software Defined Radio
A programmable PA for a software-defined radio with 20dBm
maximum output power operates based on the principle of outphasing. A
switching scheme is designed to solve the problem of power combining in
outphasing. The system is tested for GSM, EDGE, and WCMDA signals with 56%, 44%, and 30% efficiency, respectively.
Shervin Moloudi received his BS in Electronics from Sharif
University of Technology, Iran, in 1995, his MS in Digital Signal
Processing from Tampere University of Technology, Finland in 1998, and his PhD from UCLA in Integrated Circuits and Systems in 2008. He has held various technical positions in wireless and semiconductor companies, including Nokia and Broadcom, for more than 10 years and has US and international patents and publications in high speed and RF integrated circuits. He is currently a consultant and teaches at UCLA.
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JU-LAN HSU | Ph.D. Candidate
Electrical Engineering
Cross-Layer Routing and Transmission Rate Control Algorithms
for Wireless Multi-Hop CSMA/CA Ad Hoc Networks
We investigate multi-hop wireless ad hoc networks in which nodes use
software controlled radios and 802.11-based CSMA/CA MAC. Each node
independently selects its cross-layer parameter vector for each packet
that it forwards. The latter consists of the setting of the
transmission data rate and the identification of the neighboring node
to which the packet is forwarded (and thus the selection of the
route). We present an analytical model to calculate, for each
candidate parameter vector, the corresponding attainable throughput
and transport throughput capacity rates. To enable the network to
transport traffic in a throughput-effective manner, we present
cross-layer schemes under which each node configures its parameter
vector by using the corresponding link transport capacity measure as a
key metric. Depending upon whether certain neighborhood activity
status data is collected, we present two such datagram-based
cross-layer parameter vector selection schemes. We compare the
throughput performance behavior attained through the use of these
schemes, as well as with that exhibited by schemes that do not use the
link transport capacity function as a metric. Our results confirm the
precision of our analysis and demonstrate the distinct effectiveness
demonstrated by schemes that employ the link transport capacity
measure.
Ju-Lan Hsu received the B.Sc. from National Taiwan University in 2002
and the M.Sc. from University of California at Los Angeles in 2004,
both in Electrical Engineering. She is currently a Ph.D. candidate in
the Electrical Engineering Department, University of California at Los
Angeles. Her research interests include the area of cross-layer design
for ad hoc networks and wireless LANs.
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JONAS BORGSTROM | Ph.D. Candidate
Electrical Engineering
Efficient HMM-Based Estimation of Missing Features, with Applications to Robust Speech Recognition
Recently, HMM-based estimation techniques have been applied to missing feature reconstruction within various signal processing tasks. Although they have been shown to be effective in the estimation of lost features, HMM-based methods can be restrictive due to their computational load. This constraint is especially true in speech communication or speech
recognition applications, where clients may be distributed and applications may be delay-sensitive. We present efficient approximations to HMM-based estimation methods for the task of missing feature reconstruction, by means of HMM downsampling. We utilize a tree-structured mapping of quantizer centroids, allowing HMMs to be downsampled, and corresponding statistical parameters to be adapted accordingly. We derive the downsampled HMM framework in a generalized fashion, and it can thus be applied to feature estimation within a variety of applications. For illustrative purposes, we apply the proposed estimation method to channel mitigation for Remote Speech Recignition. We also utilize the proposed methods for the novel approach of HMM-based spectral reconstruction for noise robust speech recognition.
Bengt J. Borgstrom received his B.S. and M.S. from the University of California, Los Angeles, in 2004 and 2005 respectively, both in electrical engineering. He is working towards his Ph.D. in electrical engineering, also at UCLA. He is part of the Speech Processing and Auditory Perception Lab (SPAPL), directed by Professor Abeer Alwan. His interests include
noise robust recognition, audio-visual speech processing, distributed
speech recognition, and speech coding.
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ALI PARSA | Ph.D. Candidate
Electrical Engineering
New Transceiver Architecture for the 60-GHz Band
The design of RF transceivers operating in the 60-GHz band poses
many challenges at the circuit and architecture levels. In
addition to generic difficulties such as noise and high frequencies,
design in this band must deal with three critical issues:
LO (quadrature) generation, LO division, and LO distribution.
This research explores the concept of "synthesizer-friendly"
transceiver architectures so as to relax these three issues.
This presentation introduces a new transceiver architecture that
employs a 30-GHz (non-quadrature) LO, the lowest possible LO frequency if
multiplication is ruled out due to its drawbacks. With such a
choice, the third harmonic of the LO downconverts (or upconverts)
and corrupts the signal. The architecture therefore incorporates
a polyphase filter to suppress this effect. Experimental results
for prototypes realized in 90-nm CMOS technology are also
presented.
Ali Parsa was born in Tehran, Iran in 1976. He received the B.S. and M.S. degrees in electrical engineering from Sharif University of Technology in 1997 and 1999, respectively. In 1998, he joined Unistar-Micro Technology where he was involved in research and design of high-speed Analog ICs for wireless communications both in Bipolar and CMOS technologies. He is currently pursuing his PhD degree at the department of Electrical Engineering, UCLA. His major research interests are design of high-speed integrated circuits for wireless communications.
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ZHI QUAN | Ph.D. Candidate
Electrical Engineering
Spectrum Sensing Techniques for Cognitive Radio Networks
Cognitive radio has recently emerged as a promising technology to revolutionize spectrum utilization in wireless communications. In a cognitive radio network, secondary users continuously sense the spectral environment and adapt transmission parameters to opportunistically use the available spectrum. A fundamental problem for cognitive radios is spectrum sensing; they need to reliably detect very weak primary signals of possibly different types over a targeted wide frequency band. There is growing awareness that collaboration among several cognitive radios can yield considerable performance gains. This talk provides an overview of recently developed techniques for the design of cooperative sensing in cognitive radio networks. In particular, we show that cooperative spectrum sensing can utilize signal processing gains at the physical layer to mitigate strict requirements on the RF front-end and that exploiting spatial diversity through
Zhi Quan is currently pursuing his Ph.D. degree in Electrical Engineering at University of California, Los Angeles. He was a Visiting Scholar with Princeton University, Princeton, NJ. His current research interests include statistical signal processing, wireless communications and networking, multimedia communications, and cognitive radios.
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XIAOJING XU | Ph.D. Candidate
Electrical Engineering
Direct Antenna Modulation – A Promise to Go Beyond the Antenna Size Limitation
Traditionally the antenna size can not be minimized because its high radiation Q limits the system performance. The radiation physics dictates that the smaller an antenna’s size is, the higher its radiation Q becomes. And the high radiation Q is equivalent to a small efficiency-bandwidth product in a linear radiation system.
Nevertheless, the relationship between radiation Q and efficiency-bandwidth product can be broken in a non-linear time-variant system. Direction Antenna Modulation is one technique that realizes this new system concept. The proposed system integrates switches with an antenna and directly modulates the instantaneous radiation energy in the time domain. Therefore, the system optimally circulates the energy and improves the efficiency, with a modulation rate beyond the Q limitation. The Direct Antenna Modulation technique is applied to two different types of antennas and shown as examples. Simulation results of both cases show the promise of going beyond the Q and size limitation.
Xiaojing Xu received her B.S. in Electrical Engineering in University of Science and Technology of China in 2004. In the same year she started studying in Electrical Engineering department of University of California, Los Angeles. Currently she is a Ph.D. candidate. Her research interests include electrically small antennas and antenna arrays, and direct antenna modulation techniques.
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