Seminars

Robustness Guarantees with Learning in the Loop

Nikolai Matni

Postdoctoral Scholar in EECS
Unversity of California at Berkeley

Motivated by the push to incorporate learning enabled components into safety-critical systems such as autonomous ground and aerial vehicles, we seek to understand what types of robustness guarantees can be provided when the output of a machine learning (ML) algorithm is used within a robust control (RC) algorithm. ML algorithms typically view the world as stochastic, and provide probabilistic guarantees on estimation or prediction accuracy, whereas RC algorithms view the world as adversarial, and provide worst-case deterministic guarantees on system stability and performance. How then, if at all, can methods from these two fields be leveraged together? In this talk we propose the “Coarse-ID Control” framework as a way of bridging the gap between ML and RC, and apply it to a classical problem from the control literature, the Linear Quadratic Regulator (LQR), with the added twist that now the system dynamics are unknown. We provide, to the best of our knowledge, the first end-to-end, finite data robustness and performance guarantees for learning and control in an LQR problem that do not require restrictive or unrealistic assumptions. A key technical tool used in deriving this result is our recently developed System Level Approach (SLA) to Controller Synthesis. The SLA provides a transparent connection between system structure, constraints, and uncertainty and their effects on controller synthesis, implementation, and performance — we exploit these properties to combine results from contemporary high-dimensional statistics and robust controller synthesis in a way that is amenable to non-asymptotic analysis. We then show how the solution to the “Learning-LQR” problem can be incorporated into an adaptive polynomial-time algorithm with non-asymptotic convergence rate guarantees. We conclude with an overview of current experimental and simulation based validation of the Coarse-ID Control framework, and of our ongoing efforts to extend our theoretical guarantees to broader classes of systems and control algorithms.

Nikolai Matni is a postdoctoral scholar in EECS at UC Berkeley working with Benjamin Recht. Prior to that, he was a postdoctoral scholar in Computing and Mathematical Sciences at the California Institute of Technology. He received the B.A.Sc. and M.A.Sc. in Electrical Engineering from the University of British Columbia, and the Ph.D. in Control and Dynamical Systems from the California Institute of Technology in June 2016 under the advisement of John C. Doyle. His research interests broadly encompass the use of learning, layering, dynamics, control, and optimization in the design and analysis of safety-critical data-driven systems. He was awarded the IEEE Conference on Decision and Control 2013 Best Student Paper Award, the IEEE American Control Conference 2017 Best Student Paper Award (as co-advisor), and was an Everhart Lecture Series speaker at Caltech.

Wednesday, August 22, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Jovanovic

Modern Applications of Aeronautical Engineering: Geometric Nonlinear Control and Unsteady Aerodynamics

Haithem Taha

Assistant Professor
Mechanical and Aerospace Engineering Department
University of California at Irvine
Irvine, CA

Aeronautical engineering designs have been discreetly following conventional designs over the last century. Innovative leaps require advanced analysis tools that allow studying unconventional operating regimes at high frequencies and angles of attack, hence, exploiting unsteady aerodynamic phenomena and nonlinear flight dynamics, rather than obviating them, for the creation of novel efficient designs.

In this talk, I will discuss three main topics. First, I will present differential geometric control theory as a powerful analysis tool for airplane flight mechanics. Using such a theory, one may recover nonlinear controllability when linear controllability is lost due to hydraulic loss of control surfaces. Moreover, based on this formulation, I will show a novel rolling mechanism, due to nonlinear interactions between elevator and aileron, which has a significantly higher control authority near stall than the conventional linear rolling mechanism due to ailerons. Second, I will show how geometric control theory, when combined with averaging, provides rigorous mathematical tools for time-periodic systems. In particular, when applying to the hovering flight of insects or flapping-wing micro-air-vehicles, it revealed a fascinating stabilization mechanism that insects may unconsciously exploit during flight: vibrational stabilization. Finally, since these advanced flight mechanics applications necessitate accurate unsteady aerodynamic modeling, I will discuss the classical theory of unsteady aerodynamics and the unsteady Kutta condition. I will show our recent development of a viscous extension of the classical theory that does not invoke an auxiliary condition (e.g., Kutta condition). Driven by such a motivation, I will discuss our nascent idea of developing a variational theory for unsteady aerodynamics: novel framework for modeling of unsteady aerodynamics after following Prandtl’s formulation for a century.

Haithem Taha is currently an assistant professor in the department of Mechanical and Aerospace Engineering at the University of California, Irvine. He holds BSc and MSc degrees in aerospace engineering from Cairo University, Egypt in 2005 and 2008. He received his PhD degree from the Engineering Science and Mechanics department at Virginia Tech simultaneously with an MSc degree in Interdisciplinary Mathematics in Dec 2013.

Wednesday, Date August 29, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Luhar

The Intersection of Science and Policy: Key National Issues in Aerospace Technology

Mark J. Lewis

Director
Science and Technology Policy Institute
Institute for Defense Analyses
Washington, D.C.

The advancement of a technology can often hinge on the successful navigation of policy considerations in addition to inherent technical challenges. Nowhere is this more evident than in the range of policy issues related to setting national priorities in the development of aerospace technologies. These include the implementation of a national strategy for managing objects in space, the advancement of nuclear power technologies in orbit and beyond, coordinating hypersonic research across the government, the development of commercial supersonic business jets, and the realization of opportunities in deploying small satellites. This talk will consider some of the science behind the policy, as well as the policy behind the science, that is needed to inform and advance some of these aerospace capabilities. The role of various federal players, including agencies and the White House, will be described, in addition to the related organizational and bureaucratic processes. Finally, possible career paths that include the intersection of technology and policy in aerospace and other S&T areas will be discussed.

Mark J. Lewis is the Director of IDA’s Science and Technology Policy Institute, a federally funded research and development center. He leads an organization that provides analysis of national and international science and technology issues to the Office of Science and Technology Policy in the White House, as well as other Federal agencies including the National Institutes of Health, the National Science Foundation, NASA, the Department of Energy, Homeland Security, and the Federal Aviation Administration, among others.

Prior to taking charge of STPI, Dr. Lewis served as the Willis Young, Jr. Professor and Chair of the Department of Aerospace Engineering at the University of Maryland. A faculty member at Maryland for 24 years, Dr. Lewis taught and conducted basic and applied research. From 2004 to 2008, Dr. Lewis was the Chief Scientist of the U.S. Air Force. From 2010 to 2011, he was President of the American Institute of Aeronautics and Astronautics (AIAA).

Dr. Lewis attended the Massachusetts Institute of Technology, where he received a Bachelor of Science degree in aeronautics and astronautics, Bachelor of Science degree in earth and planetary science (1984), Master of Science (1985), and Doctor of Science (1988) in aeronautics and astronautics.

Dr. Lewis is the author of more than 300 technical publications and has been an adviser to more than 70 graduate students. Dr. Lewis has also served on various advisory boards for NASA, the Air Force, and DoD, including two terms on the Air Force Scientific Advisory Board, the NASA Advisory Council, and the Aeronautics and Space Engineering Board of the National Academies.

Dr. Lewis’s awards include the Meritorious Civilian Service Award and exceptional Civilian Service Award; he was also recognized as the 1994 AIAA National Capital Young Scientist/Engineer of the Year, IECEC/ AIAA Lifetime Achievement Award, and is an Aviation Week and Space Technology Laureate (2007).

Wednesday, Date September 5, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Ronney

Large-Eddy Simulation of Flow over a Circular Cylinder: The Drag and Lift Crises

D. I. Pullin

Robert H. Goddard Professor of Aeronautics
Graduate Aerospace Laboratories
California Institute of Technology
Pasadena, CA

Large-eddy simulation of incompressible flow over both a stationary and a rotating circular cylinder will be discussed. The LES are wall-resolved and the stretched-vortex subgrid-scale (SGS) model is used in the entire simulation domain. For the smooth-wall, non-rotating circular, the Reynolds number Re_D is up to 850,000 where D is the cylinder diameter. Mean-flow, secondary separation-reattachment bubbles are observed for both subcritical and supercritical Re_D. For sub-critical Re_D, the near-surface flow is interrogated using sequences in time of instantaneous portraits of the surface, vector skin-friction field. These provide insight into the onset of the drag crisis. LES is also described of flow past a span-wise grooved cylinder at Re_D from 3,900 to 60,000 with a ratio of groove amplitude to diameter of 1/32. This flow also shows a drag crisis. Comparison of flow features with the smooth-wall flow shows structural differences but significant similarities. It is argued that common features of these flows suggest an underlying mechanism for the drag crisis. Additionally, LES will be described of flow past a rotating circular cylinder. This flow exhibits both lift and drag crises. The relevant mechanisms underlying these phenomena will be discussed.

Dale I. Pullin received his PhD in Aeronautics at Imperial College London in 1974. His research interests include computational and theoretical fluid mechanics, vortex dynamics, compressible flow and shock dynamics, turbulence, and large-eddy simulation of turbulent flows. He is presently Robert H. Goddard Professor of Aeronautics at the California Institute of Technology.

Wednesday, September 12, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Bermejo-Moreno

Do Robots Need to Look Like Humans?

Dennis Hong

Professor
Mechanical and Aerospace Engineering Department
University of California at Los Angeles
Los Angeles, CA

In Hollywood, robots are often depicted in the humanoid form. Thus when we think of robots we naturally imagine humanoid robots. For robots to move around in a human environment and to do work using tools made for humans, it is natural to have robots that have the shape and size of a human. We have been developing humanoid robots at RoMeLa (Robotics & Mechanisms Laboratory) for more than a decade for fire fighting and disaster relief applications. However, such robots are still too slow, too unstable, too complex, too expensive, and too unsafe which prevent them to be used in real life situations. Do robots really need to look like humans? We revisit this question and present some of the new exciting morphologies as solutions, discuss the creative process, and imagine our future with robots.

Dennis Hong, a TED alumnus, is a Professor and the Founding Director of RoMeLa (Robotics & Mechanisms Laboratory) of the Mechanical & Aerospace Engineering Department at UCLA. His research focuses on robot locomotion and manipulation, autonomous vehicles and humanoid robots. He is the inventor of a number of novel robots and mechanisms, including the ‘whole skin locomotion’ for mobile robots inspired by how amoeba move, a unique three-legged waking robot STriDER, an air-powered robotic hand RAPHaEL, and the world’s first car that can be driven by the blind. His work has been featured on numerous national and international media. Washington Post magazine called Dr. Hong “the Leonardo da Vinci of robots.”

Dr. Hong has been named to Popular Science’s 8th annual “Brilliant 10”, honoring top scientists younger than 40 years of age from across the United States, “Forward Under 40” by the University of Wisconsin-Madison Alumni Association, and also honored as “Top 40 Under 40” alumni by Purdue University. Hong’s other past awards include the National Science Foundation’s CAREER award, the SAE International’s Ralph R. Teetor Educational Award, and the ASME Freudenstein / GM Young Investigator Award to name a few. Dr. Hong also actively leads student teams for various international robotics and design competitions winning numerous top prizes including the DARPA Urban Challenge where they won third place and the $500,000 prize, and the RoboCup, the international autonomous robot soccer competition where his team won First Place in both the Kid-Size and Adult-Size Humanoid divisions and brought the Louis Vuitton Cup Best Humanoid Award to the United States for the very first time.

Dr. Hong received his B.S. degree in Mechanical Engineering from the University of Wisconsin-Madison (1994), his M.S. and Ph.D. degrees in Mechanical Engineering from Purdue University (1999, 2002).

He is also a serious gourmet chef and a magician performing annual charity magic shows and lectures on the science of magic.

Wednesday, September 19, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Gupta

Understanding and Exploiting Cancer Mechanobiology

Adam J. Engler

Professor
Department of Bioengineering
University of California, San Diego
Sanford Consortium for Regenerative Medicine
La Jolla, CA

Mammary epithelial cells (MECs) are classically known to respond to differences in extracellular matrix (ECM) stiffness by transitioning to a malignant, non-polarized state on stiffer ECM, i.e. Epithelial-Mesenchymal Transition (EMT). While this is akin to stiff mammary tumors that one can detect with manual palpation, breast cancer fibrosis is dynamic and stiffening occurs over months to years. I will describe our efforts to more accurately mimic the onset of tumor-associated fibrosis using dynamic methacrylated-hyaluronic acid (MeHA) hydrogels, whose stiffness that can be modulated from normal 100 Pa to malignant 5000 Pa, utilizing a two step polymerization process. Contrary to previous observations, we find that collective decisions by MECs in 3D aggregates called acini indicate partial protection from the stiffened niche. To interpret MEC mechano-signaling that result in this protection, I will also present our new understanding of the molecular mechanisms used by MECs to interpret stiffness, i.e. Hippo/YAP/TAZ/LETS (Nature 2018) and Twist signaling (Nature Cell Bio 2015). After cells leave this niche, however, mechanical changes can be exploited to improve metastatic detection. I will conclude my presentation with new data showing that we can use differences in cell-ECM adhesion strength to mark metastatic cells even in mixed or lineage committed populations (Biophys J 2017), potentially improving future prognostic capacity when diagnosing and treating epithelial tumors

Adam J. Engler is a Professor and Vice-Chair of Bioengineering at UC San Diego, where he has been on the faculty since 2008. He also is a resident scientist at the Sanford Consortium for Regenerative Medicine. Dr. Engler previously trained with Dr. Dennis Discher at the University of Pennsylvania, where he earned his PhD studying how ECM stiffness regulated stem cell fate. He also trained as a postdoc with Dr. Jean Schwarzbauer at Princeton University’s Department of Molecular Biology.

Dr. Engler’s research focuses on how physical and chemical properties of the niche influence or misregulates cell function and modifies genetic mechanisms of disease. In particular, his lab studies the phenomenon in the context of cardiovascular and musculoskeletal diseases and cancer. To accomplish this, his lab makes natural and synthetic matrices with unique spatiotemporal properties to mimic niche conditions, improve stem cell behavior and commitment in vitro, or direct them for therapeutic use in vivo.

Dr. Engler has received numerous awards in recognition of this research, including young investigator or mid-career awards from International Society for Matrix Biology (2008), Biomedical Engineering Society (2008), American Society of Matrix Biology (2014), American Society of Mechanical Engineering (2015), and American Society for Engineering Education (2018). Dr. Engler is a fellow of the American Institute for Biomedical Engineering and recipient of an NIH New Innovator Award grant.

Wednesday, September 26, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Oberai

Active Mechanics and Flows in the Cell

Michael Shelley

George and Lilian Lyttle Professor of Applied Mathematics
Courant Institute
New York University
New York, NY
and
Group Leader
Biophysical Modeling
Flatiron Institute
Simons Foundation
New York, NY

Many fundamental phenomena in eukaryotic cells — nuclear migration,spindle positioning, chromosome segregation — involve the interaction of (often transitory) cytoskeletal elements with boundaries and fluids. Understanding the consequences of these interactions require specialized numerical methods for their large-scale simulation, as well as mathematical modeling and analysis. In this context, I will discuss the recent interactions of mathematical modeling and large-scale, detailed simulations with experimental measurements and perturbations of activity-driven biomechanical processes within the cell.

Michael Shelley Michael Shelley holds a PhD in Applied Mathematics (1985) from the University of Arizona. He was a postdoctoral researcher at Princeton University, and then joined the faculty of mathematics at the University of Chicago (1988). He joined the Courant Institute at New York University in 1992 where he is the George and Lilian Lyttle Professor of Applied Mathematics. Since 2015 he has also been the Group Leader in Biophysical Modeling at the Flatiron Institute of the Simons Foundation.

Wednesday, October 3, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Kanso

Why Morph?

Jayanth N. Kudva

Chief Executive Officer
NextGen Aeronautics, Inc.
Torrance CA
jkudva@nextgenaero.com

Morphing, i.e., changing the shape (or more generally the state) of an aircraft has been a major focus of the smart materials and structures R&D community for more than two decades. The overarching goal is to provide multi-point optimization at the system level, for example to realize wing shapes which could be optimal across a wide speed range, potentially enabling development of aircraft which are ultra-efficient and have multi-mission capabilities.

Key and critical technology enablers are materials which are: i) multi-functional and ii) can be easily integrated in the aircraft structure. While much fundamental and applied research has been conducted in this area, technology transition with demonstrated performance improvements has been limited. The reasons for this are many and varied; this talk will discuss the rationale for morphing aircraft designs, potential benefits and costs, technology and operational limitations, and thoughts on the future course of smart materials technology development. The talk will also explore related and complementary technologies including health monitoring and structurally integrated antenna structures which would have synergistic benefits at the system level for development of continuously optimal and operationally flexible aircraft.

The talk will also address the joys and challenges of running a small, agile, aerospace R&D company.

Dr. Kudva is the CEO of NextGen Aeronautics Inc. (www.nextgenaero.com ). Prior to founding NextGen in 2003, he worked at Northrop Grumman, where he managed a Structures R&D group and pioneered R&D work in smart, adaptive and morphing structures under DARPA and AFRL sponsorship.

He was awarded the SPIE Smart Structures and Materials Life Time Achievement Award in 2007 and the AIAA Adaptive Structures Prize in 2010. He was selected to be an AIAA Fellow in 2015.

Wednesday, October 10, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Spedding & Luhar

Möbius Kaleidocycles: A New Class of Everting Ring Linkages

Eliot Fried

Mathematics, Mechanics, and Materials Unit
Okinawa Institute of Science and Technology Graduate University
Onna, Okinawa, Japan
eliot.fried@oist.jp

Many mechanical devices from scissors to robotic arms are characterizable as `linkages’ or sets of rigid links connected by moving joints. Known linkages displaying a single degree-of-freedom, which facilitates control, have hitherto consisted of six or fewer links. In this talk, we will introduce a new class of one-degree-of-freedom ring linkages ‘Möbius kaleidocycles.’ These objects consist of seven or more identical hinge-joined links and might thus serve as building blocks in positioning, extrusion, and pultrusion systems, to instance a few among many promising applications in engineering, architecture, robotics, and chemistry. They also pose a myriad of intriguing fundamental questions, some of which will be touched upon in this talk. This is joint work with postdoctoral scholar Hannes Schönke.

Monday, October 15, 2018
11:00 AM
The Laufer Library (RRB 208)

host: Newton & Luhar

Homogenization in Inelastic Material Systems

Sanjay Govindjee

Horace, Dorothy, and Katherine Johnson Endowed Professor
Structural Engineering, Mechanics, and Materials
Department of Civil and Environmental Engineering
University of California at Berkeley
Berkeley CA

Given an inelastic material model, a structural geometry, and a set of boundary conditions, one can in principle always solve the governing equations to determine the system’s mechanical response. However, for large inelastic systems this procedure can quickly become computationally overwhelming, especially in three-dimensions and when the material is locally complex, has microstructure. In such settings multi-scale modeling offers a route to a more efficient model by holding out the promise of a framework with fewer degrees of freedom, which at the same time faithfully represents up to a certain scale the behavior of the system.

In this talk, we present a methodology that produces such models for inelastic systems upon the basis of a variational scheme. The essence of the scheme is the construction of a variational statement for the strain energy as well as the dissipation potential for a coarse scale model in terms of the strain energy and dissipation functions of the fine scale model. From the coarse scale energy and dissipation we can then generate coarse scale material models that are computationally far more efficient than either directly solving the fine scale model or by resorting to FE2 type modeling. An essential feature for such schemes is the proper definition of the coarse scale inelastic variables. By way of concrete examples, we illustrate the needed steps to generate successful models via application to finite deformation nonlinear viscoelasticity within the microsphere framework and by application to problems in classical plasticity.

Sanjay Govindjee is a Professor of Civil Engineering and the Horace, Dorothy, and Katherine Johnson Endowed Professor at the University of California, Berkeley (1993-2006, 2008-present). His main interests are in theoretical and computational mechanics with an emphasis on micro-mechanics, shape memory alloys, and elastomers. Prior to joining Berkeley he worked as an engineer at the Lawrence Livermore National Laboratory (1991-1993) in Livermore, California. He was also Professor of Mechanics at ETH Zürich (2006-2008) in Zürich, Switzerland.

Sanjay Govindjee obtained a Ph.D. in Mechanical Engineering with a minor in Physics from Stanford University in 1991 under the guidance of the late Prof. Juan C. Simo and a M.S. in Mechanical Engineering from Stanford University in 1987. His S.B. is in Mechanical Engineering from the Massachusetts Institute of Technology in 1986. Dr. Govindjee also serves as a consultant to several governmental agencies and private corporations. He is an active member in major societies such as the American Society of Mechanical Engineers and the US Association for Computational Mechanics. He is also a registered Professional Mechanical Engineer in the state of California.

Noteworthy honors include a National Science Foundation Career Award, the inaugural 1998 Zienkiewicz Prize and Medal, an Alexander von Humboldt Foundation Fellowship 1999, a Berkeley Chancellor’s Professorship 2006-2011, and a guest Professorship at ETH Zürich 2008-2013. In 2015 he was named a Fellow of the US Association for Computational Mechanics. In 2018 he received a Humboldt-Forschungspreis (Humboldt Research Award).

Wednesday, October 17, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Oberai

Towards Dextrous Locomotion with Biomimetic Millirobots

Ronald S. Fearing

John William McKay Jr. Electrical Engineering Professor
Dept. of Electrical Engineering and Computer Sciences
Univ. of California, Berkeley
Berkeley, CA

Decimeter-scale robots will soon be able to access and maneuver in a wide range of environments previously only accessible by animals. To achieve dextrous locomotion at the small-scale requires a high power-to-weight ratio and mechanical design which can exploit environment interactions, in addition to control strategies. Recent advances in planar fabrication allow low-cost manufacture of robust milli-scale robot designs. We have found that aspects of intelligent behavior can arise from intrinsic mechanics, which is particularly useful for under-actuated systems. For these systems, appendages such as claws and tails greatly improve maneuverability. In addition, the study of small animals such as insects, birds, and lizards has lead to “implicit intelligence” principles which can be applied to the design of biomimetic millirobots.

Ronald S. Fearing is the John William McKay Jr. Electrical Engineering Professor in the Dept. of Electrical Engineering and Computer Sciences at Univ. of California, Berkeley, which he joined in Jan. 1988. He was Vice-Chair for Undergraduate Matters from 2000-2006, and is Vice-Chair for Graduate Matters (2016-present). His current research interests are in bioinspired milli-robotics, including flying and crawling milli-robots, cooperative locomotion, rapid prototyping, parallel nano-grasping (gecko adhesion) and micro-assembly. He has worked in tactile sensing, teletaction, and dextrous manipulation. He has a PhD from Stanford in EE (1988) and SB and SM in EECS from MIT (1983). He received the Presidential Young Investigator Award in 1991, and is the co-inventor on 18 US and international patents.

Wednesday, October 24, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Gupta

Fluid Transport by Self-Propelled Zooplankton

Monica Martinez Wilhelmus

Assistant Professor
Mechanical Engineering
University of California at Riverside
Riverside, CA

Fluid transport is an imminent by-product of swimming. Yet, the fluid dynamic mechanisms available for self-propelled organisms to disperse properties and nutrients, and eventually diffuse concentration gradients via mixing, are not fully understood. The focus of this talk will be on transport by zooplankton species hypothesized to act as ecosystem engineers and contribute to vertical mixing in the upper ocean. Experimental observations and recent numerical results both at the organism and group level demonstrating large-scale transport pathways during vertical migration will be discussed. In particular, the role of the near-body field in redistributing fluid particles via entrainment at the wake, an effect often overlooked in numerical simulations, will be highlighted. I will close this talk by presenting recent advances by my group in designing and constructing a robotic swimmer that leverages key kinematic and morphological parameters of zooplankton (E. superba) directly related to transport. The long-term objective aims to develop a new generation of underwater self-propelled robots capable of maximizing fluid transport and operating in the transitional regime where both viscous and inertial effects are important. The creation of such a platform would prove beneficial in the context of sensing and water treatment.

Monica Martinez Wilhelmus is an assistant professor in Mechanical Engineering at the University of California, Riverside (UCR) and an affiliated scientist at NASA Jet Propulsion Laboratory (JPL). Prior to joining UCR, she held a one-year postdoctoral scholar position to work on a collaborative project between the Ocean Science group at NASA JPL and the Environmental Science and Engineering department at the California Institute of Technology (Caltech). She received her undergraduate degree in Mechanical Engineering from the Universidad Nacional Autonoma de Mexico (UNAM) in 2010, and her M.S. (2012) and Ph.D. (2016) degrees, both in Mechanical Engineering, from Caltech. Her research combines experimental techniques and numerical simulations to understand transport phenomena within the intersection of biology, oceanography and fluid mechanics.

Wednesday, October 31, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Bermejo-Moreno

Next Dimension of Detection: Biomechanical Analysis of Tissue Using Optical Elastography

Andrea Armani

Ray Irani Chair in Chemical Engineering and Materials Science and Professor of Chemical Engineering and Materials Science, Biomedical Engineering, Electrical Engineering-Electrophysics, and Chemistry
University of Southern California
Los Angeles, CA

Understanding the mechanical behavior of biological materials is immensely complex due to the heterogeneity of the architecture at both the nano- and micro-scale. For example, in a tissue slice, cells are connected by the extracellular matrix (ECM). While it is clear that the ECM and the cells have different stiffness values, recent results show an inter-dependence between the two systems. However, it is not clear if the cells change in response to changes in ECM stiffness or vice versa. The nature of this dependence is of particular importance in tissue where the structure and mechanical properties directly determine the physiological behavior. Therefore, understanding the cause and effect has the potential to inform treatment; for example, understanding resistance to therapies, organ rejection, and disease progression. However, measuring the sample stiffness in unprocessed tissue is a particularly complex task. We have recently demonstrated a fully integrated polarimetric elastography instrument for characterizing the mechanical properties of visco-elastic materials, including living, resected tissue. This portable system shows promise for rapid testing and characterization of animal and human tissue samples, enabling numerous types of research investigations.

Andrea Armani received her BA in physics from the University of Chicago and her PhD in applied physics with a minor in biology from the California Institute of Technology. She is currently the Ray Irani Chair of Engineering and Materials Science and a Professor of Chemical Engineering and Materials Science at the University of Southern California. She is the Director of two nanofabrication cleanrooms at USC: the W. M. Keck Photonics Cleanroom and the soon to open John D. O’Brien Nanofabrication Laboratory. She is on the Board of ACS Photonics and the World Economic Forum’s Expert Network, a member of Sigma Xi and NAI, a senior member of IEEE and AIChE, and a Fellow of OSA and SPIE. She has received several awards, including the ONR Young Investigator Award, the PECASE, and the NIH Director’s New Innovator Award, and she was named a Young Global Leader by the World Economic Forum.

Wednesday, November 7, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Bermejo-Moreno

The Physiology of the Filling Heart from an Engineering Perspective

Sándor J. Kovács

Professor of Medicine and Physiology
and
Adjunct Professor of Physics and Biomedical Engineering

Washington University School of Medicine
St Louis, MO

How the heart works, particularly when it fills, has been a field of investigation since Aristotle! Amazingly, diastolic (filling) function remains an active field of investigation and controversy to this day. Since filling involves volume changes, pressures, flows, valves and motion it is natural to characterize it using engineering principles and laws of motion. I will review the role of the heart as an indefatigable muscle powered oscillator, a (near perfect) constant volume pump, a suction pump in diastole and as a pressure/volume pump in systole. Invasive (cardiac catheterization) and noninvasive imaging (echocardiography, cardiac MRI, cine CT) of heart function/motion has advanced understanding. Kinematic modeling of filling is predictive, it solves the ‘inverse problem of diastole’ and allows for model validation, leading to ultimate clinical application. A beneficial byproduct of the engineering approach and kinematic modeling is unification of previously unexplained phenomenologic observations under a single mechanistic conceptual framework and prediction of ‘new’ physiology.

Sándor Kovács was born in Budapest, escaped Hungary in 1956 with his family, and immigrated to US in 1959. He is a 1965 graduate of Brooklyn Technical HS, and of Cornell in 1969 with a BS in analytical engineering. Graduate studies continued at Caltech, initially in Theoretical and Applied Mechanics, with subsequent transfer to theoretical physics. His 1977 thesis was titled ‘The Generation of Gravitational Waves’ with Kip Thorne as advisor. As a result of influence by George Zweig at Caltech, his interests were redirected to life sciences/physiology, and he earned an MD 22 months later in 1979 through Univ. of Miami’s PHD to MD program. Internship, residency, cardiology fellowship at Washington University Med Center in St. Louis followed, and he joined the faculty there in 1985. He established the Cardiovascular Biophysics Laboratory (a theory group) in the late 1980s. The laboratory has seen the graduation of nearly two dozen doctoral students and had research support from the VA, NIH, AHA, Whitaker Foundation and Wolff charitable trust. Currently Dr. Kovács is a professor of Medicine, Physiology, Biomedical Engineering and Physics. He received the Sjöstrand Medal from the Swedish Society of Clinical Physiology in 2007 for advances in cardiovascular physiology and biophysics and was elected distinguished foreign member of the Hungarian Society Of Cardiology in 2010. He was awarded an honorary doctoral degree by LUND University in 2018.

Wednesday, November 14, 2018
3:30 PM
Seaver Science Library, Room 150 (SSL 150)

Refreshments will be served at 3:15 pm.

host: Pahlevan