The seminar for this week is cancelled due to MICCAI 2016
Numerous physical systems are governed by partial differential equations or involve delays/transport. Such infinite-dimensional models have been a challenge to the ODE-accustomed control engineers who seek feedback designs that are both constructive and provide stability guarantees. About 15 years this situation changed with the emergence of “continuum backstepping” approach for PDEs. The backstepping designs, whose initial applications were for Navier-Stokes equations, yield explicit feedback laws which convert the original system into a desired well-behaved “target system” (for Navier-Stokes, the target is a heat equation system). I will present the basic methodological ideas of PDE backstepping and illustrate them with examples that come from fluid flows, phase change, 3D printing, multi-vehicle robotic swarms, microbial populations, and opinion spreading in online social networks.
Miroslav Krstic holds the Alspach endowed chair and is the founding director of the Cymer Center for Control Systems and Dynamics at UC San Diego. He also serves as Associate Vice Chancellor for Research at UCSD. As a graduate student, Krstic won the UC Santa Barbara best dissertation award and student best paper awards at CDC and ACC. Krstic is Fellow of IEEE, IFAC, ASME, SIAM, and IET (UK), Associate Fellow of AIAA, and foreign member of the Academy of Engineering of Serbia. He has received the PECASE, NSF Career, and ONR Young Investigator awards, the Axelby and Schuck paper prizes, the Chestnut textbook prize, the ASME Nyquist Lecture Prize, and the first UCSD Research Award given to an engineer. Krstic has also been awarded the Springer Visiting Professorship at UC Berkeley, the Distinguished Visiting Fellowship of the Royal Academy of Engineering, the Invitation Fellowship of the Japan Society for the Promotion of Science, and the Honorary Professorships from the Northeastern University (Shenyang), Chongqing University, and Donghua University, China. He serves as Senior Editor in IEEE Transactions on Automatic Control and Automatica, as editor of two Springer book series, and has served as Vice President for Technical Activities of the IEEE Control Systems Society and as chair of the IEEE CSS Fellow Committee. Krstic has coauthored eleven books on adaptive, nonlinear, and stochastic control, extremum seeking, control of PDE systems including turbulent flows, and control of delay systems.
Management of carotid artery disease, towards preventing strokes, currently relies on a simple algorithm, which has proved insufficient for a large number of mostly asymptomatic subjects, posing a significant clinical challenge. Ultrasound imaging in combination with image analysis hold promise for addressing this challenge, through the in vivo estimation of morphological, mechanical and anatomical features of the carotid artery, the artery that takes blood to the brain.
This presentation highlights various advanced image analysis techniques applied on carotid ultrasound, in an attempt to identify novel risk markers and optimise disease management. Texture features, estimated from static images, describe different patterns of tissue allocation, presumably as a consequence of exerted stresses. Mechanical features, estimated from temporal image sequences, characterise tissue elasticity and are more sensitive to early tissue changes due to ageing or disease. Anatomical features, including arterial diameters, wall thickness and lesion size, can be automatically extracted using segmentation tools. These methodologies, along with biochemical and clinical indices, are integrated in a web-based platform, which relies on a semantically-aided architecture and allows for intelligent archival and retrieval of data, thus facilitating and enhancing the entire diagnostic procedure.
In view of the valuable information on lesion composition and stability revealed by ultrasound-image-based features, and the noninvasiveness and low-cost of ultrasound imaging, these approaches are directed towards improved risk stratification, increased patient safety and cost-efficiency. Their clinical usefulness remains to be demonstrated in large trials.
Spyretta Golemati is Assistant Professor in Biomedical Engineering and a member of the First Intensive Care Unit of the Medical School of the University of Athens.
Dr Golemati holds a Diploma in Mechanical Engineering from the National Technical University of Athens, Greece, and a M.Sc. and a Ph.D. degree in Bioengineering from Imperial College London, UK.
Her research interests include (a) medical image analysis, with emphasis on vascular ultrasound image analysis, (b) biosignal processing, and (c) vascular physiology and pathophysiology. She has co-authored 32 papers published in international scientific peer-reviewed journals, 12 book chapters, and 44 papers published in international scientific peer-reviewed conference proceedings. She has participated in 7 funded national and international research projects (in one, as co-ordinator). Dr Golemati has acted as reviewer of national and international research proposals as well as of papers submitted to international scientific journals and conferences. She is a member of the Institute of Electrical and Electronic Engineers [Engineering in Medicine and Biology Society (IEEE-EMBS), Ultrasonics, Ferroelectrics and Frequency Control (IEEE-UFFC)], the Technical Chamber of Greece, and the Hellenic Atherosclerosis Society. She is Associate Editor of the journal Ultrasonics. She is a grantee of the Fulbright Foundation-Greece for the academic year 2016-2017.
Thanksgiving Break – no seminar
Catheters play a key role in diagnosing and treating cardiac arrhythmia. Intracardiac echo (ICE) catheters enable real-time 2D ultrasound image acquisition from within the heart, however, manually steering ICE catheters inside a beating heart is a complex and time consuming task. The clinical use of ICE catheters is therefore limited to only a few critical tasks, such as septal puncture. At the Harvard Biorobotics Lab, we built a robotic system that can automatically steer four degree-of-freedom catheters, enabling real-time tracking of instruments within the heart and 3D visualization of cardiac tissue. In this talk, I will walk you through the design process in preparing our system for in vivo trials, and present results from our latest live animal experiment. I will describe the control strategies we employed to accurately steer these flexible manipulators in the presence of external disturbances (e.g. respiratory motion) and unmodeled motion of the catheter body. Finally, I will describe the GPU-accelerated image processing pipeline we used to generate 3D volumetric images of the heart in real-time from the 2D images acquired by the ICE catheter.
Alperen Degirmenci is a PhD candidate in Engineering Sciences at the Harvard John A. Paulson School of Engineering and Applied Sciences. He has been working in the BioRobotics Laboratory since 2012 under the supervision of Prof. Robert D. Howe. Alperen earned his M.S. degree from Harvard University in 2015, and a B.S. degree in Mechanical Engineering from the Johns Hopkins University in 2012, with minors in mathematics, computer science, robotics, and computer-integrated surgery. Alperen’s research at Harvard focuses on real-time, high-performance algorithm development for medical ultrasound image processing and robotic procedure guidance in catheter-based cardiac interventions.
Patients with peripheral field loss complain of colliding with other pedestrians in open-space environments such as shopping malls. Field expansion devices (e.g., prisms) can create artificial peripheral islands of vision. We investigated the visual angle at which these islands can be most effective for avoiding pedestrian collisions, by modeling the collision risk density as a function of bearing angle of pedestrians relative to the patient. Pedestrians at all possible locations were assumed to be moving in all directions with equal probability within a reasonable range of walking speeds. The risk density was found to be highly anisotropic. It peaked at ≈ 45° eccentricity. Increasing pedestrian speed range shifted the risk to higher eccentricities. The risk density is independent of time to collision. The model results were compared to the binocular residual peripheral island locations of 42 patients with forms of retinitis pigmentosa. The natural residual island prevalence also peaked at about 45° nasally but at about 80° temporally. This asymmetry results in a complementary coverage of the binocular field of view. Field expansion prism devices will be most effective if they can create artificial peripheral islands at about 45° eccentricities. The collision risk and residual island findings raise interesting questions about normal visual development.
Dr. Eli Peli earned a BSc in Electrical Engineering and an MSc in Biomedical Engineering from the Technion Israel Institute of Technology. He then came to Boston where he received his OD degree from the New England College of Optometry. Currently Dr. Peli is the Moakley Scholar in Aging Eye Research at Schepens Eye Research Institute, Massachusetts Eye and Ear, and Professor of Ophthalmology at Harvard Medical School. He also serves as Adjunct Professor of Ophthalmology at Tufts University School of Medicine. Since 1983 he has been caring for visually impaired patients as the director of the Vision Rehabilitation Service at the New England Medical Center Hospitals (now Tufts-Medical Center). Dr. Peli is a Fellow of the American Academy of Optometry, a Fellow of the Optical Society of America, a Fellow of the SID (Society for Information Display), and a Fellow of the SPIE (The International Society of Optical Engineering). He was presented the 2001 Glenn A. Fry Lecture Award and the 2009 William Feinbloom Award by the American Academy of Optometry, the 2004 Alfred W. Bressler Prize in Vision Science (shared with Dr. R. Massof) by the Jewish Guild for the Blind, the 2006 Pisart Vision Award by the Lighthouse International, the 2009 Alcon Research Institute award (shared with Dr. R. Massof), the 2010 Otto Schade Prize from the SID (Society for Information Display) and the 2010 Edwin H Land Medal awarded jointly by the Optical Society of America and the Society for Imaging Science and Technology. He was awarded an Honorary Degree of Master in Medicine by Harvard Medical School in 2002 and an Honorary Doctor of Science Degree from the State University of New York (SUNY) in 2006. Dr. Peli’s principal research interests are image processing in relation to visual function and clinical psychophysics in low vision rehabilitation, image understanding and evaluation of display-vision interaction. He also maintains an interest in oculomotor control and binocular vision. Dr. Peli is a consultant to many companies in the ophthalmic instrumentation area and to manufacturers of head mounted displays (HMD). He served as a consultant on many national committees, including the National Institutes of Health, NASA AOS, Aviation Operations Systems advisory committee, US Air Force, Department of Veterans Affairs, US Navy Postdoctoral Fellowships Program, US Army Research Labs, and US Department of Transportation, Federal Motor Carrier Safety Administration. Dr. Peli has published more than 200 peer reviewed scientific papers and has been awarded 9 US Patents. He edited a book entitled Visual Models for Target Detection with special emphasis on military applications and co-authored a book entitled Driving with Confidence: A Practical Guide to Driving with Low Vision.