Seminars, Talks & Colloquia at SEAS
Spring 2009

GW Institute for Biomedical Engineering Colloquia: Contrast Ultrasound and NADH Fluorescence Imaging of Myocardial Perfusion

Simultaneous imaging of myocardial flow and hypoxia could be vital for identifying acute ischemic mechanisms that may trigger an arrhythmia. We have studied the distribution of flow and hypoxia in excised locally ischemic rat hearts using simultaneous contrast ultrasound imaging and beta-nicotinamide adenine dinucleotide (NADH) fluorescence imaging. Local ischemia was induced by controlling flow within a major coronary artery. Intra-myocardial flow was imaged using contrast high-resolution ultrasound (linear probe; 13-6 MHz). An ultrasound contrast agent (UCA) was used to highlight the ischemic border. We observed distinct borders between two perfusion beds. UCA images showed high contrast borders of flow. The progression of UCA through the tissue was clearly visible. Intra-myocardial regions of flow overlap could be identified by superimposing images of UCA from two perfusion zones. Borders between hypoxic and normoxic tissue were clearly revealed by increased NADH fluorescence. Hypoxic borders were oriented along borders of flow. In summary, simultaneous ultrasound and NADH imaging of excised hearts from small animals provide high fidelity images for characterizing the distribution of flow and hypoxic tissue during acute localized ischemia.

This work was funded by the American Heart Association, the NIH, as well as the GW Institute of Biomedical Engineering (IBE) through an IBE Research Instrumentation Grant and an IBE Undergraduate Research Fellowship.

For more information, please visit www.ibe.gwu.edu.

GW Institute for Biomedical Engineering Colloquia: Biosensor Development at the Naval Research Laboratory: Design, Function and Theory

Biosensors are highly sensitive and selective detection systems, with uses ranging from common clinical analyses to emerging rapid field sensors. I have spent the last 20 years designing and building biosensors at the Naval Research Laboratory. I will describe the development, design and function of three biosensor systems: an evanescent wave fiber optic biosensor, an array-based evanescent wave biosensor and a micro-flow cytometer that can be used for highly multiplexed assays. These systems represent an evolution of technology towards smaller, faster, better, and I will describe the weaknesses that were improved in each evolutionary step.

Pizza and refreshments will be served.

For more information, please visit www.ibe.gwu.edu.

Transportation Safety, Planning and Evaluation

Dr. Samer Hamdar, assistant professor of CEE, will give a talk on Friday, February 6th from 11:30 to 12:30 in Room 204, Research I Building at the Virginia Campus. The talk is entitled “Transportation Safety, Planning and Evaluation: Modeling Evacuation as well as Modeling Driver and Pedestrian Behavior.” Pizza and drinks will be provided. Please RVSP to Judy Shem at (703) 726-8515. Dr. Steve Kan encourages you to take this informal opportunity to meet Dr. Hamder and to learn more about his current and future research plans.

AIAA Distinguished Lecture Series: From Rocks to Rovers: The Role of Field Geology in the Return to the Moon

Contact James Stephenson at james_s@gwmail.gwu.edu for more information.

GW Institute for Nanotechnology (GWIN) Seminar: Miniature Mobile Robots Down to Micron Scale

Abstract:
Please see the abstract for more information.

ECE Colloquium Series: Semi-Blind Source Separation with Sparseness Constraints

Abstract:
Blind source separation (BSS) is now well established theory with a number of reported applications across science and engineering. The basic static linear BSS problem is efficiently solved by probabilistic approach known as independent component analysis (ICA) under standard assumptions: sources are statistically independent and non-Gaussian, and number of sensors is equal to or greater than the unknown number of sources. This talk will focus on underdetermined blind and non-blind source separation (uBSS) problem (number of sensors is less than the number of sources) solved by non-probabilistic (geometric) approach known as sparse component analysis (SCA). It assumes that sources are sparse in some basis and relies on clustering and -norm minimization. For nonnegative uBSS problem solution based on hierarchical alternating least square nonnegative matrix factorization will be presented. The SCA methods will be demonstrated on computer generated examples as well as on two real world problems: blind multi-spectral image decomposition and compressed sensing of the images of natural scenes.

Biography
Ivica Kopriva received his Ph.D. degree in electrical engineering from the Faculty of Electrical Engineering and Computing, Zagreb, Croatia in 1998, with the topic in non-imaging infrared sensing systems based on blind source separation. Currently, he is senior scientist at the Ruder Boškovic Institute, Zagreb, Croatia. His research activities are related to the algorithms for blind signal processing with applications to inverse problems in imaging and spectroscopy. Dr Kopriva spent four years, 2001-2005, at the Department of Electrical and Computer Engineering, The George Washington University, Washington DC, US. His work was related to the theory of blind signal processing with applications to blind image deconvolution and unsupervised decomposition of multispectral and hyperspectral images. Other important area of his research was on direction finding (DF) systems, where he helped to build two-linear-antenna-arrays direction finding system as well as to develop novel covariance and quadri-covariance based DF algorithms. In co-authorship with Te-Ming Huang and Vojislav Kecman, Dr Kopriva wrote a research monograph Kernel Based Algorithms for Mining Huge Data Sets: Supervised, Semi-supervised and Unsupervised Learning, published in Springer Series: Studies in Computational Intelligence, 2006. He holds one US Patent.

If there are any questions, please contact Dr. Harrington at rharring@gwu.edu.

Computer Science Seminar: OER Models that Build a Culture of Collaboration: A Case Exemplified by Curriki

Abstract:
This talk explores the impact that Open Educational Resources (OER) can have on eliminating the “Education Divide.” Advances in information technologies have created unique opportunities for the free exchange and access to knowledge on a global scale. To this end, a growing number of education organizations and foundations are finding that an open source approach can bridge the educational content gap.

Open Source Curriculum (OSC) based on the open source model empowers educators to freely exchange ideas, and leads to the development of best practices and world-class curricula. Curriki, an online community for creating and sharing open source K-12 curricula, is a pioneer in applying an open source approach to curriculum development. Drawing on the social network model, Curriki is advancing a collaborative culture of learning, creating and sharing that is paramount to a networked learning environment. Committed to the idea that access to knowledge is a basic right for every child, Curriki is a “disruptive change” that is transforming the traditional model of how content is developed, published, distributed and evaluated. The opportunity exists today to empower every teacher that wants to teach and every student that wants to learn with high-quality open source educational resources at no cost.

Dr. Barbara (Bobbi) Kurshan has honed her vision of “what can be” using technology while supporting the growth of new education companies and developing innovative software products. As the Executive Director of Curriki she is helping to build the best global open source curricula community. Curriki is a non-profit, social entrepreneurship organization that supports the development and free distribution of open source educational materials to improve education worldwide. Dr. Kurshan also founded WorldSage in 2004 with the vision to create a for-profit higher education system to address education for the 21st Century and currently serves on the board.

Dr. Kurshan has been involved with education and technology for over 30 years. She developed the first children’s software products for Microsoft—Creative Writer and Fine Artist—and also created award-winning products for McGraw-Hill, Apple, CCC (Pearson) and others. As a professor, she helped students research the impact of technology on learning. Dr. Kurshan also publishes articles based on personal research exploring women’s attitudes toward technology, how kids learn using computers, and new ways of learning through understanding. She has been quoted in many influential journals and serves as a reviewer and advisor to research projects for the National Science Foundation and other government and business groups.

Through her venture fund, Core Learning, she invested in companies and entrepreneurs who are impacting education. Currently she serves on the board of several education technology companies, including Interschola and Fablevision. Among numerous honors, Dr. Kurshan received the Education Academic Society’s Making It Happen Award and the Highest Leaf Award from the Women’s Venture Fund. She is listed in Who’s Who in Technology Today.

Dr. Kurshan received her Ed.D. and M.S. in Computer Science from Virginia Tech University and her B.S. from Newcomb College, Tulane University.

Computer Science Seminar: In-Memory Databases

Abstract:
VeriSign supports .com, .net and several other Domain Name registries. The associated resolution services require 100% availability -- being down for maintenance or as a result of failure is simply unthinkable.

Availability and redundancy are almost synonymous in industry thinking; as availability requirements grow, more machines are added in the hope that something will stay up somewhere. Although such redundancy mitigates physical failures, it reduces performance and increases complexity; this increases the likelihood of software or human failure, leaving us short of the goal. Redundancy by itself just isn't enough to achieve continuous availability.

Continuous availability also isn't achieved by simply adding more layers of software on top of all the popular layers of software; it rather requires a transition similar to aviation's transition from pistons and propellers to jet engines - fewer parts moving faster.

Our distributed memory-based data base takes this "simplify" approach to the extreme. We aggressively avoid "nice" in pursuit of a simplicity that can only makes allowance for "need". We limit functionality to bare essentials, even SQL is avoided for its complexity. The result is simply fantastic.

George Hillenbrand started working with computers the summer of 1968, back when serious programmers wrote in 360 assembly language, computer science wasn't an engineering major, and computer memory cost significantly more than a dollar a byte.

George graduated from Cornell, then worked for a decade at NCR where, among other things, he wrote a multi-tasking operating system that fit within 4K of memory. In the 80's and 90's he worked for Nortel and was the architect for a directory assistance search system that is still used today across much of the United States. After consulting for several years, he joined VeriSign to build the high availability distributed in-memory database that is the topic of today's talk.

Computer Science Seminar: Human Factors Experiments with Augmented Reality Systems

Abstract:
Augmented reality (AR) has shown much promise, but limited practical usage outside the laboratory environment. One reason is that some fundamental aspects of perception in AR are not well-understood. I will summarize some recent user studies on visual acuity, contrast sensitivity, color perception, and depth perception with augmented reality systems. Our strategy with these measurements is to compare objective standards, performance with a user's natural vision, and performance with an AR system. The results show a mixed set of comparable and distorted perception, depending on the display and the whether one is looking at real or virtual objects.

Mark A. Livingston, Ph.D. is a research scientist in Advanced Information Technology at the Naval Research Laboratory. He directs and conducts research on interactive graphics, including augmented reality and visual analytics, with a focus on perceptual and cognitive factors. He received his PhD in 1998 from the Univ. of North Carolina at Chapel Hill, focusing on tracking systems for augmented reality and medical applications of the technology.

For more information, please contact the Department of Computer Science at 202-994-4765.

ECE Colloquium Series: ExCoV: Expansion-Compression Variance-Component Based Sparse-Signal Reconstruction from Noisy Measurements

Abstract:
An expansion-compression variance-component based method (ExCoV) for reconstructing sparse or compressible signals from noisy measurements will be presented. The measurements follow an underdetermined linear model, with noise covariance matrix known up to a constant. To impose sparse or compressible signal structure, we define high- and low-signal coefficients, where each high-signal coefficient is assigned its own variance, low-signal coefficients are assigned a common variance, and all the variance components are unknown. Our expansion-compression scheme approximately maximizes a generalized maximum likelihood (GML) criterion, providing an approximate GML estimate of the high-signal coefficient set and an empirical Bayesian estimate of the signal coefficients. Our approach is automatic and does not employ a convergence criterion. We apply the proposed method to reconstruct signals from compressive samples, compare it with existing approaches, and demonstrate its performance via numerical simulations. When presenting numerical examples, a brief introduction to compressive sampling will be given.

Biography
Aleksandar Dogandžic received the Dipl. Ing. degree (summa cum laude) in Electrical Engineering from the University of Belgrade, Yugoslavia, in 1995, and the M.S. and Ph.D. degrees in electrical engineering and computer science from the University of Illinois at Chicago (UIC) in 1997 and 2001, respectively. In August 2001, he joined the Department of Electrical and Computer Engineering, Iowa State University (ISU), where he is currently an Associate Professor. His research interests are in statistical signal processing: theory and applications. Dr. Dogandžic received the 2003 Young Author Best Paper Award and 2004 Signal Processing Magazine Best Paper Award, both by the IEEE Signal Processing Society. In 2006, he received the CAREER Award by the National Science Foundation. At ISU, he was awarded the 2006-2007 Litton Industries Assistant Professorship in Electrical and Computer Engineering. Dr. Dogandzic serves as an Associate Editor for the IEEE Transactions on Signal Processing.

If there are any questions, please contact Dr. Harrington at rharring@gwu.edu.

Computer Science Seminar: Automatic In-depth Malware Analysis

Abstract:
Malicious software (i.e., malware) has become a severe threat to interconnected computer systems for decades and caused billions of dollars damages each year. Large volume of new malware samples are discovered daily. Even worse, malware is rapidly evolving to be more sophisticated and evasive to strike against current malware analysis and defense systems. My research tackles the problem of automatic in-depth malware analysis, which aims to automatically analyze a piece of malware, identify its malicious behavior, and provide valuable insights about its attack mechanism. My first step was to build a new dynamic binary analysis platform, TEMU, to address the common challenges for malware analysis, including code obfuscation, pervasive and transient code presence, and fine-grained malicious behaviors. TEMU not only enables my research on malware analysis, but also fosters research on other computer security problems. Then on the basis of TEMU, I proposed a series of novel techniques, such as Panorama, Renovo, and HookFinder, for detecting and analyzing various aspects of malware. These techniques capture intrinsic characteristics of malware, and thus are well suited for dealing with new malware samples and attack mechanisms.

Heng Yin is a PhD candidate at College of William and Mary under the supervision of Prof. Haining Wang (at William & Mary) and Prof. Dawn Song (at UC Berkeley). His research interests span all aspects of security, including computer security, software security, and network security. His current focus is on binary analysis techniques and their applications to malware defense. Since October 2005, he is one of the initiators and major participants of the BitBlaze binary analysis project at UC Berkeley (previously at Carnegie Mellon University).

For more information, please contact the Department of Computer Science at 202-994-4765.

GW Institute for Nanotechnology: Magnetophotonic Materials and Their Applications /Magnetophotonic Crystals with Various Designs

Abstract:
Within the last two decades progress in nanotechnology has allowed creating with high accuracy structures composed of dielectric materials with different refractive indices, known as photonic crystals (PCs) and shown to manipulate the flow of light. For magnetophotonic crystals (MPCs), in which the constitutive elements exhibit magneto-optical (MO) response, there exists an additional degree of freedom to operate the photonic band structure, diffraction patterns, and the state of polarization of light, i.e., their characteristics can be altered by magnetic fields. MPCs are certainly considered as nextgeneration fast and miniature elements for use in integrated optics. The large MO enhancement is particularly attractive for constructing nano-sized film-type optical isolator/circulator elements for optical communication systems as theoretically predicted, and ultra-high speed MO spatial light modulators for high density holographic data storage as examined experimentally. This talk focuses on functional performances of 1D MPCs with different designs: MPCs composed of alternating magnetic and dielectric layers, and MPCs with the localized states in PBGs. The MO response of garnet–noble metal nanocomposites, which can be used as constituent material for MPCs, are studied. Possible applications of 1D and 2D MPCs are briefly reviewed.

We have recently demonstrated that tailoring of surfaces of PCs provides a new approach to engineer responses of known materials. 1D MPCs with structures of (SiO2/Ta2O5)5/(Bi:YIG/SiO2)5 and (SiO2/Bi:YIG)5/Au were fabricated onto quartz substrates using sputtering. Parameters of these multilayers were chosen such that they supported spectrally narrow localized surface states, the so-called optical Tamm states (OTSs). Calculations show that the distribution of the electric field amplitude is remarkably high at the interface between (SiO2/Ta2O5)5 and (Bi:YIG/SiO2)5 {or (SiO2/Bi:YIG)5 and Au film, for the second sample} and falls exponentially away from the interface. Such a distribution confirms the formation of the OTS. All the maxima of the OTS’s amplitude are spatially located within (or close to) the Bi:YIG layers. The OTSs were spectrally located within photonic band gaps and were associated with a sharp transmission peak in measured spectra of the MPCs. Substantial enhancement of the Faraday rotation for the wavelength of OTS was experimentally observed and attributed to strong light coupling to Bi:YIG constituents of the MPCs. Another representatives of MPCs under our study were autocloned (Bi:YIG/SiO2)7 multilayers with a quasi-2D structure and 3D magneto-photonic structures composed of thin opal and Bi:YIG films. It was found that light coupling to these periodical structures results in enhancement of their MO responses. Interestingly, the large reverse rotation was observed, which is likely governed by an amplitude-phase relationship between beams emerging from the MPCs.

GW Institute for Biomedical Engineering Colloquia: Instantaneous Mean Frequency and Phase Maps in Studying Human VF Dynamics

Cardiac arrhythmias are lethal and could seriously affect the quality of living. While there are therapeutic solutions available for tackling atrial fibrillations (AF) which are relatively less lethal, ventricular fibrillation (VF), the lethal of the arrhythmias is still elusive in spite of 100 years of research. VF is a non-stationary process and it manifests into variations in the waveform morphology, phase, and frequency dynamics of the electrograms. A joint time-frequency (TF) approach would be the best way to analyze the electrogram data acquired during VF. This talk will present one such TF approach to extract the instantaneous mean frequency (IMF) from inter cardiac electrograms acquired simultaneously from the epicardium and endocardium of the isolated human hearts and study the spatio-temporal frequency changes during VF. Unlike the well-known dominant frequency (DF) approach where the instantaneous temporal evolution of spectral characteristics is lost, the proposed IMF approach could track the temporal frequency changes over space. These evolving frequency patterns over time can be correlated with the locations of phase singularities in phase maps to reveal better mechanistic insights on the dynamics of the VF sources. The potential of the proposed approach in tracking migratory sources and conduction blocks during VF will be presented with examples and the possibility of using this information to modulate VF for focal therapies will be discussed.

Pizza and refreshments will be served.

For more information, please visit www.ibe.gwu.edu.

Computer Science Seminar: Human Factors Experiments with Augmented Reality Systems

Please see the seminar announcement or contact the Department of Computer Science at 202-994-4765 for more information.

GW Institute for Biomedical Engineering Colloquia: Optical Biosensors and a Perspective on the Future

Optical biosensors are moving from the laboratory to the point of use. New concepts for molecular recognition, integration of microfluidics and optics, simplified fabrication technologies, systems integration concepts, and public concerns drive this movement. These factors are discussed and examples of innovations are identified that will lead to smaller, faster, cheaper optical biosensors with capacity to provide effective and actionable information. NRL biosensors with different capabilities and at different stages in development will be used to illustrate the factors that are impacting biosensor design for point of use systems.

Frances S. Ligler, D.Phil., D.Sc. (Oxford University), is currently the Navy's senior scientist for biosensors and biomaterials and vice chair of the bioengineering section of the National Academy of Engineering. She has published over 300 full-length articles in scientific journals and has 24 issued patents; together they have been cited over 5,300 times. She performs research in biosensors, microfluidics, and nanotechnology. In 2003, she was awarded the Homeland Security Award by the Christopher Columbus Foundation and the Presidential Rank of Distinguished Senior Professional by President Bush.

Pizza and refreshments will be served.

For more information, please visit www.ibe.gwu.edu.

ECE Colloquium Series: The Virginia Cross Campus Grid

Abstract:
Modern grids have tremendous potential for the scientific community both in terms of increasingly large resource pools from which to draw compute power and in terms of scientific collaboration. However, despite this potential, adoption by users remains quite low. Grids usually prove difficult to learn and use resulting in user frustration. In essence, grids fail to provide adequate user interfaces for their very target audience. Genesis II and the XCG at the University of Virginia are challenging these stereotypes and have built a compute (primarily for High-throughput computation) and data grid that attempts to ease the average user into grid functionality by presenting him or her with a familiar user interaction abstraction – namely that of the file system. By presenting grid resources as files and directories Genesis II enables not only a more seamless user experience but also one more readily manipulated by scientific research techniques such as shell scripts and legacy executables. In this talk I will give a brief overview of grid technology and will then describe in detail the Genesis II system and the cross-campus grid or XCG initiative currently underway there.

Biography
Mark Morgan received his Masters of Science in Computer Science from the University of Virginia in 1999. As the Senior Software Engineer at Avaki Corporation from 2000 to 2003 he helped transition the Legion grid project from an academic research project to a commercialized compute and data grid product. Now back at the University of Virginia as a member of the Computer Science Department's Research Faculty and as the lead software architect for Genesis II he continues to stay very active in grid research. He maintains an active role in the Open Grid Forum having chaired one working group and co-authored a number of specifications in other groups. His interests include Programming Languages, Computer Architecture, and Operating Systems.

If there are any questions, please contact Dr. Harrington at rharring@gwu.edu.

Joint MAE and COBRE Seminar: Towards Robotic Flies

Abstract:
We seek to elucidate how to apply biological principles to the creation of robust, agile, inexpensive robotic insects. However, biological inspiration alone is not sufficient to create robots that mimic the agile locomotion of their arthropod analogs. This is particularly true as the characteristic size of the robot is decreased: to create high performance articulated robotic insects, we must explore novel manufacturing paradigms, new forms of actuation and sensing, and alternative control strategies for under-actuated, nonlinear, computationally-limited systems. This talk will highlight research in the Harvard Microrobotics Lab aimed at creating a flying robotic insect the size of a housefly.

Biography
Robert Wood is an assistant professor in Harvard's School of Engineering and Applied Sciences (SEAS). Prof. Wood completed his M.S. (2001) and Ph.D. (2004) degrees in the Dept. of Electrical Engineering and Computer Sciences at the U. C. Berkeley. He is founder of the Harvard Microrobotics Lab, which contains advanced facilities for rapid prototyping on the micron to centimeter scale. His current research interests involve the creation of biologically-inspired aerial and ambulatory microrobots, the unsteady aerodynamics of flapping-wing flight, minimal control of under-actuated nonholonomic nonlinear dynamical systems, and decentralized control of multi-agent systems. He is the winner of a 2007 DARPA Young Faculty Award, a 2008 NSF Career Award, a 2008 ONR Young Investigator Award, a 2008 Air Force Young Investigator Award, multiple best paper/video awards, and is a member of the 2008 class of Technology Review’s TR35.

For more information, please call 202-994-6749.