Graduate Seminar - Fall 2008

All seminars to be held at 3:00 p.m. on Fridays in Kaufman 224. For more information, contact Dr. Sacharia Albin at (757)683-3741 or e-mail salbin@odu.edu. Refreshments will be provided.

Date	Seminar Details
August 29	Albin/Graduate Advising
September 5	Dr. Shu Xiao Assistant Professor Electrical & Computer Engineering and Frank Reidy Research Center for Bioelectrics Old Dominion University, VA   Host: Dr. Albin   Title: "SUBNANOSECOND ELECTRICAL PULSES FOR MEDICAL THERAPIES AND MEDICAL IMAGING"   Abstract: The use of prolate-spheroidal reflectors as part of a sub-nanosecond Impulse Radiating Antenna (IRA) allows us to generate near-field electric fields with high spatial resolution in biological tissue. If the power of such ultrashort electrical pulses is very high, it becomes possible to deposit substantial electromagnetic energy into deep-lying tissue, even at the rather high conductivity and consequently strong absorption of most tissues. This electromagnetic energy may be used either to stimulate bioelectric effects, such as pulsed electric field induced apoptosis of tumor cells, or to generate local hyperthermia. Besides using ultrashort electrical pulses for medical therapies, the use of Impulse Radiating Antennas in the hundred-picosecond temporal range leads to medical imaging methods with sub-centimeter spatial resolution based on diffraction limit. The method is based on the measurement of changes in the complex permittivity of tissue, and may complement imaging methods based on the measurement of other physical parameters. For example, breast tumors are characterized by conductivity and permittivity approximately a factor of five higher than surrounding healthy tissue. The design and construction of subnanosecond pulse generators has resulted in a 160 ps, 50 kV, 50 W generator. The design of prolate-spheroidal antennas for these medical applications is pursued in cooperation with C.E. Baum at the University of New Mexico. A three-dimensional, time-dependent electromagnetic code (MAGIC) is used to model the electric field distribution in tissue. The pulse power research efforts are complemented by studies on the biological effect of subnanosecond electrical pulses.
September 12	Dr. Gon Namkoong Assistant Professor Department of Electrical and Computer Engineering Old Dominion University, VA Host: Dr. Albin Title: "Current Trend of III-Nitride Research and Renewable Energy Sources" Abstract: Reliable energy source will be an important part of the future strategy to meet economic development, national security and clean environment in the United States. Most of current power sources come from fossil fuel and nuclear power. This will result in increased payments for imported energy sources to meet an increasing consumption. To sustain the reliable energy, the use of finite fossil resources has to be gradually replaced by developing renewable energy technologies so that green house gas emissions have to be decreased substantially. This requires the development of novel materials for next-generation energy sources. III-nitride materials and their devices can offer new advanced technologies which can reduce power saving and develop high efficiency renewable energy sources. Furthermore, nitride materials can replace bulky and energy-hungry UV sources by solid state UV diodes. Current development of III-nitride materials will be introduced, including white light emitting diodes (LEDs), UV LEDs and high efficiency solar cells which have a potential of more than 60% energy-conversion efficiency.           To produce cheaper renewable energy source, flexible organic materials have been recently introduced for photovoltaic applications and enable innovative and reliable elements that were not possible by traditional technologies (e.g. flexible organic solar cells can be wrapped around surfaces, rolled up or even painted onto structures). Organic solar cells will replace expensive and rigid counterparts of Si solar cells with solution based, very cheap and roll-to-roll fabrication process. They will harvest more energy by applying larger surface areas even with very cheap prices. An integrated research will be introduced for the development of flexible organic solar cell technologies and their potential use of more efficient and light-weight solar cells for satellites and spacecraft.
September 19
September 26	Dr. Yuanwei Jin Assistant Professor of Electrical Engineering Department of Engineering and Aviation Sciences University of Maryland Eastern Shore. Host: Dr. Song Title: "Time Reversal Detection and Imaging" Abstract: Electromagnetic waves propagating in a rich scattering environment reflect and scatter from many objects, resulting in the creation of multiple paths from the transmitter to the receiver. Traditionally, this multipath propagation adversely affects the electromagnetic channels, posing a challenge to many real world applications, for example, radar detection and imaging.  Time reversal is a new approach that takes advantage of multipath scattering to improve target detection and imaging resolution. In time reversal, we reverse a signal dispersed by a scattering environment and retransmit it through the same (reciprocal) medium. Both the experimentally measured electromagnetic data and the finite-difference time-domain propagation simulation data have shown that time reversal obtains improved resolution and produces clean target map by exploring constructively the scattering and multipath in the propagation through inhomogeneous channels. I will also talk about the research by time reversal in other applications, including guided ultrasonic wave detection and imaging for natural gas pipeline monitoring and breast cancer detection and imaging. Biography: Yuanwei Jin is an Assistant Professor with the Department of Engineering and Aviation Sciences of University of Maryland Eastern Shore. Prior to joining UMES, he was a Post-Doctoral Fellow, and then a Research Scientist with the Department of Electrical and Computer Engineering at Carnegie Mellon University.  He obtained his Ph.D. in electrical and computer engineering from the University of California at Davis in 2003. His research interests are signal and image processing for radar, wireless communications, and biomedical imaging. He is a Senior Member of IEEE, a member of Sigma Xi, and an associate member of the American Association for Cancer Research.
October 3	Sachin Shetty, PhD Assistant Professor Department of Electrical and Computer Engineering Rowan University Host: Dr. Song   Title: "Learning-based strategy for Multi-user and Multi-channel Opportunistic Spectrum Access"   Abstract: With the advent of cognitive radio technology, opportunistic spectrum access has the potential to mitigate spectrum scarcity and meet the increasing demand for spectrum. In this talk, the problem of how multiple secondary users achieve maximal throughput in an opportunistic spectrum access (OSA) network is addressed. The secondary users adopt a slotted transmission scheme to exploit spectrum opportunities in a multi-channel unslotted primary network. In each slot, a secondary user chooses one channel to sense and decide whether to access based on the sensing outcome. A sensing strategy for intelligent channel selection is crucial to track the rapidly varying spectrum opportunities. In an ad hoc network without a central controller or common control channels, a secondary user can only resort to its local observations in the decision making. The tradeoff is between choosing the channel most likely to be idle and avoiding other competing secondary users. We show that the channel sensing decision problem for the secondary users is formulated as a constrained partially observable Markov decision process. We designed and developed a learning based OSA approach. This approach effectively addresses this design tradeoff and offers significant improvement in network throughput over the optimal single-user design.   About the Presenter: Sachin Shetty received Bachelor of Science in Computer Engineering from Mumbai University, India in 1998. He received his Master of Science in Computer Science from University of Toledo in 2002.  He then earned his PhD degree from Old Dominion University in 2007. He is currently an Assistant Professor with the Department of Electrical and Computer Engineering at Rowan University. He has authored and co-authored 15 international refereed conference publications, journal articles, and book chapters. His main research areas are design and performance analysis of mobile ad hoc networks and wireless sensor networks, cognitive networking, network security, wireless communications, packet switching, and distributed data mining. He also teaches upper level undergraduate and graduate courses in data communications and wireless networks at Rowan University.
October 10	Dr. Federico Rosei Professor, INRS-EMT, Univ. du Quebec Canada Research Chair in Nanostructured Organic and Inorganic Materials Varennes (QC), Canada Host: Dr. Elsayed-Ali   Title: "Exploring Assembly At The Nanoscale"   Abstract: The bottom-up approach is emerging as a viable alternative to the top down paradigm currently in use for fabricating nanostructured materials [1]; it is based on the concept of self-assembly of suitable nanostructures on a substrate, exploiting the balance between adsorbate-adsorbate and adsorbate-surface interactions. We are exploring various strategies to control nanostructure assembly (both organic and inorganic) at the nanoscale. New experimental tools and comparison with simulations are presented to gain fundamental insight into the surface processes that govern nucleation, growth, alloying and assembly [2-5]. We are able to control the size and luminescence properties of semiconductor nanostructures, synthesized by reactive laser ablation [6-8]. Our approaches include surface patterning through a nanostencil [9,10] (i.e. a shadow mask with nanoscale features) and deposition on naturally patterned substrates, which take advantage of long-range surface reconstructions [11]. By exploiting inter-molecular interactions, we can create specific nanoscale patterns with long range order [12-18]. The general concept that underpins these studies is the idea of using surface cues, that can guide molecular units upon adsorption [19]. The controlled assembly of nanoscale building blocks is promising for many applications, ranging from nanoelectronics to chemical and biosensors, to improved biomaterials [20-22].   About the Presenter:  Federico Rosei received a Laurea degree (1996) and a PhD (2001) in Physics from the University of Rome "La Sapienza". He worked as a Post-Doctoral Research Associate and Marie Curie Fellow at the Center for Atomic Scale Materials Physics in Aarhus (Denmark) from the end of 2000 until April 2002. He then joined the faculty at INRS- Energie, Materiaux et Telecommunications, Université du Québec as Assistant Professor in May 2002. Only two years later, he was promoted to Associate Professor, with tenure. He is recipient of a Strategic FQRNT Fellowship for New Professors from the Province of Quebec and holds the Canada Research Chair in Nanostructured Organic and Inorganic Materials. Dr. Rosei's research interests focus on the properties of nanostructured materials, and on how to control their size, shape, composition, stability and positioning when grown on suitable substrates. He has extensive experience in fabricating, processing and characterizing inorganic, organic and biocompatible nanomaterials. He has co-authored over 70 articles in prestigious international journals (including Science, Physical Review Letters, J. Am. Chem. Soc., Angewandte Chemie, Advanced Materials, Nanoletters, Small, Phys. Rev. B and Applied Physics Letters) and has given over 70 Invited, Keynote and Plenary Talks at international conferences and over 95 seminars at Universities, Government and Industrial Laboratories since 2000.
October 17
October 24	Dr. Karl H. Schoenbach Eminent Scholar Batten Endowed Chair in Bioelectric Engineering Frank Reidy Research Center for Bioelectrics. Host: Dr. Dhali   Title: "BIOELECTRICS - USING PULSED ELECTRICAL POWER TECHNOLOGY TO CONTROL BIOLOGICAL CELL FUNCTIONS"   Abstract: The use of pulsed electric fields on biological cells is not new. A method called electroporation has been used for decades to introduce drugs or DNA into cells for basic science or for therapeutic purposes. Pulse durations for electroporation range from milliseconds to microseconds. Another domain of pulsed electric field interactions with cell structures and functions opens when the pulse duration is reduced to values below the characteristic charging time of the outer cell membrane (which is generally in the submicrosecond range). Electrical models for biological cells predict that reducing the duration of applied electrical pulses to values below this characteristic time causes a strong increase in the probability of electric field interactions with intracellular structures. This intracellular access allows the manipulation of cell functions.  Experimental studies, in which human cells were exposed to pulsed electric fields of up to 300 kV/cm amplitude with durations as short as 10 ns, have confirmed this hypothesis and have shown that it is possible to selectively alter the behavior and/or survival of cells. Observed nanosecond pulsed effects at moderate electric fields include intracellular release of calcium with long term implications on cell behavior and function.  At increased electric fields, the application of nanosecond pulses induces programmed cell death (apoptosis) in biological cells. Applications for nanosecond pulse effects cover a wide range: from rather straightforward biofouling prevention in cooling water systems, to advanced medical applications, such as gene therapy and tumor treatment. Results of this continuing research are leading to the development of wound healing and skin cancer treatments, which are discussed in some detail.
October 31
November 7	Dr. Christopher Rose WINLAB, Rutgers University. Host: Dr. Popescu
November 14
November 21	Albin/Graduate Advising
November 28	Thanksgiving