Thursday, March 1
3:30 to 4:30 p.m.
38-138 Engineering IV
Abstract: The goal of my research is to improve human-robot collaboration by integrating mathematical models of human behavior into robot decision making. I develop game-theoretic algorithms and probabilistic planning techniques that reason over the uncertainty in the human internal state and its dynamics, enabling autonomous systems to act optimally in a variety of real-world collaborative settings. While much work in human-robot interaction has focused on leader-assistant teamwork models, the recent advancement of robotic systems that have access to vast amounts of information suggests the need for robots that take into account the quality of the human decision making and actively guide people towards better ways of doing their task. In this talk, I propose an equal partners model, where human and robot engage in a dance of inference and action, and I focus on one particular instance of this dance: the robot adapts its own actions via estimating the probability of the human adapting to the robot. I start with a bounded memory model of human adaptation parameterized by the human adaptability – the probability of the human switching towards a strategy newly demonstrated by the robot. I then propose data-driven models that capture subtler forms of adaptation, where the human teammate updates their expectations of the robot’s capabilities through interaction. Integrating these models into robot decision making allows for human-robot mutual adaptation, where coordination strategies, informative actions and trustworthy behavior are not explicitly modeled, but naturally emerge out of optimization processes. Human subjects experiments in a variety of collaboration and shared autonomy settings show that mutual adaptation significantly improves human-robot team performance, compared to one-way robot adaptation to the human.
Speaker Bio: Stefanos Nikolaidis completed his Ph.D. at Carnegie Mellon’s Robotics Institute in December 2017 and he is currently a research associate at the University of Washington, Computer Science & Engineering. His research lies at the intersection of human-robot interaction, algorithmic game-theory and planning under uncertainty. Stefanos develops decision making algorithms that leverage mathematical models of human behavior to support deployed robotic systems in real-world collaborative settings. He has a MS from MIT, a MEng from the University of Tokyo and a BS from the National Technical University of Athens. He has additionally worked as a research specialist at MIT and as a researcher at Square Enix in Tokyo. He has received a Best Enabling Technologies Paper Award from the IEEE/ACM International Conference on Human-Robot Interaction and was a Best Paper Award Finalist in the International Symposium on Robotics.
Friday, March 2
10:30 a.m. to 12 p.m.
2101 Engineering V
Abstract: Nanostructured materials have become critically important in many areas of technology, ranging from renewable energy, electronics, photonics, to biology and medicine, because of their unusual physical/chemical properties due to confined dimensions of such materials. In this talk, I will present an exciting class of polymeric materials we developed recently: nanostructured conducting polymer gels (nCPGs) that are hierarchically porous, and structurally tunable in terms of size, shape, composition, hierarchical porosity, and chemical interfaces. nCPGs as functional organic building blocks offer an array of advantageous features such as intrinsic 3D nanostructured conducting framework, exceptional electrical conductivity and electrochemical activity to store and transport ions, synthetically tunable structures and chemical interfaces, and they have been demonstrated powerful for a number of significant applications in energy and environmental technologies. Several latest examples on nCPGs-enabled advanced energy and environmental applications such as high-energy lithium batteries, self-healing electronics, solar steam generation and water desalination, and atmosphere water harvesting, will be discussed to illustrate ‘structure-derived multifunctionality’ of this special class of materials.
Speaker Bio: Dr. Guihua Yu received his B.S. degree with the highest honor in chemistry from University of Science and Technology of China, and earned his Ph.D. from Harvard University with Charles Lieber, followed by postdoc research at Stanford University with Zhenan Bao. Currently Yu is an Associate Professor of Materials Science and Engineering at University of Texas at Austin. His research interests include rational synthesis and self-assembly of functional organic and hybrid organic-inorganic nanomaterials, and fundamental understanding of their chemical/physical properties for advanced energy and environmental technologies.
Monday, March 5
9 a.m. to 12 p.m.
5628 Math Sciences Building
This seminar introduces R packages and functions that help users import, transform and manage their data in preparation for analysis. The seminar focuses on the “tidy data” philosophy encouraged by the “tidyverse” collection of R packages, but draws on other packages for useful functions as needed. Topics include data import, transforming variables, string functions, missing data, merging datasets, reshaping data, grouped data processing, and looping. NOTE: All researchers are welcome to attend.
Monday, March 5
11 a.m. to 12:30 p.m.
54-134 Engineering IV
Abstract: Hardware plays a critical role in today’s security landscape. Every protocol with security or privacy guarantees inevitably includes some hardware in its trusted computing base. The increasing number of vulnerability disclosures calls for a more rigorous approach to secure hardware designs. In this talk, I will present several cryptographic primitives to enhance the security of hardware. I will first discuss the use of Physically Obfuscated Keys (POK) to strengthen the security of private keys. In particular, I will present a computational fuzzy extractor based on the Learning Parity with Noise (LPN) problem. Our construction uses stability information as a trapdoor to correct a constant fraction of POK errors efficiently. Next, I will describe our work on Oblivious RAM (ORAM), a cryptographic primitive to prevent access pattern leakage. I will present both architectural and algorithmic improvements to ORAM. While hardware is often trusted as a line of defense, it can also be utilized by attackers. The advent of ASIC hash units calls into question the security of hash functions and proof-of-work systems. I will describe bandwidth-hard functions to achieve ASIC resistance and briefly touch on my other projects in blockchains and consensus.
Speaker Bio: Ling Ren is a final year graduate student at Massachusetts Institute of Technology. He received his Master’s degree from Massachusetts Institute of Technology and Bachelor’s degree from Tsinghua University. His research interests span computer security, cryptography, computer architecture and distributed computing. He won the best student paper award at CCS 2013.
Wednesday, March 7
11 a.m. to 1 p.m.
57-124 Engineering IV
Abstract: As an emerging technology and new computing paradigm, quantum computing has a great potential to solve problems that are theoretically and empirically hard. Among all the existing quantum computation models, quantum annealing has drawn significant attention in recent years due to the realization of the commercialized quantum annealer, sparking research interests in developing applications to solve problems that are intractable for classical computers. In this study, we focus on solving Boolean satisfiability (SAT) problem using quantum annealer while addressing practical limitations on actual quantum annealer. We propose a mapping technique that maps SAT problem to quadratic unconstrained binary optimization, and we also devise a tool flow that embeds the QUBO onto the actual architecture of the quantum annealing device. Additionally, our tool optimizes the embedding result by shortening the qubit chain size and enlarging the energy gap, leading to robust computation.
Speaker Bio: Juexiao Su is currently a Ph.D. candidate in the Department of Electrical and Computer Engineering under the mentorship of Professor Lei He. He received the M.S. degree from UCLA in 2013, and B.S. Degree from Beihang University, Beijing, China in 2011. He worked as an intern in the Synopsys verification group, and information sciences institute, USC.
Wednesday, March 7
3 to 4 p.m.
37-124 Engineering IV
Abstract: Nanoscale electronic devices and biological circuit elements such as neurons are ‘pathologically’ nonlinear in their current-voltage behavior. In 1963 Ridley postulated that, under appropriate biasing conditions, a system that exhibits either a current-controlled or a voltage-controlled negative differential resistance (NDR) will bifurcate, via entropy-production-maximization, to form regions with different current-densities or electric-fields, respectively. The ensuing discussions in the non-equilibrium statistical mechanics community, however, failed to agree on the specific mechanisms causing such bifurcations. Using thermal and chemical spectro-microscopy, my group directly imaged current-density- and electric-field-bifurcations in metal oxides that are being used to implement threshold resistance switching in memristors and neuro-mimetic devices. We found that nonlinear dynamical circuit theory, which is admittedly an approximation to Maxwell’s equations, and the principle of local activity successfully predict chaotic behavior and both current-density- and electric-field-bifurcations, as well as provides a mechanism for why the bifurcations occur. We determined that upon bifurcations, internal enthalpy in the device reduces despite unchanged power input and heat output, thus suggesting an important thermodynamic constraint required to model the operations of nonlinear electronic devices. Our results explain the electroforming process that initiates nonvolatile switching in some metal oxides, and has significant implications for properly modeling any semiconductor device, since bifurcation can occur for many types of activated processes. Standard multi-physics modeling packages can quantitatively approximate the total static current flowing in a circuit, but qualitatively predict incorrect static and dynamic behavior if a bifurcation has occurred. This has significant implications for understanding the operation and the lifetime/reliability of nonlinear electronic devices.
Speaker Bio: R. Stanley Williams is a Senior Fellow and Senior Vice President at Hewlett Packard Labs in Palo Alto, CA. For the past 40 years, his primary scientific research has been in the areas of solid-state chemistry and physics and their applications to technology. This has taken him on a journey that began with surface science; expanded to electronic, photonic and ionic nanotechnologies; and now encompasses computation, chaos, complexity and neuroarchitectonics.
Thursday, March 8
11 a.m. to 12:30 p.m.
54-134 Engineering VI
Abstract: The recent proliferation of acoustic devices, ranging from voice assistants to wearable health monitors, is leading to a sensing ecosystem around us — referred to as the Internet of Acoustic Things or IoAT. My research focuses on developing hardware-software building blocks that enable new capabilities for this emerging future. In this talk, I will sample some of my projects. For instance: (1) I will demonstrate carefully designed sounds that are completely inaudible to humans but recordable by all microphones; (2) I will discuss our work with physical vibrations from mobile devices, and how they conduct through finger bones to enable new modalities of short range, human-centric communication; and (3) finally, I will draw attention to various acoustic leakages and threats that arrive with sensor-rich environments. I will conclude this talk with a glimpse of my ongoing and future projects targeting a stronger convergence of sensing, computing, and communications in tomorrow’s IoT, cyber-physical systems, and healthcare technologies.
Speaker Bio: Nirupam Roy is a Ph.D. candidate in Electrical and Computer Engineering at the University of Illinois, Urbana-Champaign (UIUC). His research interests are in mobile sensing, wireless networking, and embedded systems with applications to IoT, cyber-physical-systems, and security. Roy is the recipient of the Valkenburg graduate research award, the Lalit Bahl fellowship, and the outstanding thesis awards from both his Bachelor’s and Master’s institutes. His recent research on “Making Microphones Hear Inaudible Sounds” received the MobiSys’17 best paper award and was selected for the ACM SIGMOBILE research highlights of the year in 2017.
Abstract: Random fiber networks are present in many biological and man-made materials. Examples from the living world include the cellular cytoskeleton and various types of connective tissue. Examples from the non-living world include paper, rubber, gels, insulation and hygiene consumer products. In this work we study the relationship between the microstructure and the mechanical properties of the network, with emphasis on identifying regimes in which large changes of the system scale behavior are triggered by small changes in system parameters. Results pertaining to multiple types of networks will be presented and contrasted, including networks made from a single type of fiber and composite networks made from fibers of multiple types, densely cross-linked, sparsely cross-linked and non-cross-linked networks. Networks of non-cross-linked nanofibers interacting by adhesion form a separate class of such systems; the role of adhesion in defining the mechanical behavior of networks of fiber bundles will be discussed. Damage accumulation and failure in random networks will be also discussed, with emphasis on the relationship between the strength of the fibrous material and its microstructure.
Speaker Bio: Prof. Picu received his PhD degree from Dartmouth College and spent two years as Research Associate at Brown University. He joined the Department of Mechanical, Aerospace and Nuclear Engineering at Rensselaer Polytechnic Institute in 1998, where he is now Professor and Associate Head. He is the author or co-author of two books, multiple book chapters and over 170 journal articles. His research focuses on mechanics of materials, and in particular, on understanding the macroscopic material behavior based on physics taking place on multiple scales. He is a fellow of ASME.
Friday, March 9
5 to 6 p.m.
E-IV Tesla Room #53-125
Abstract: Atomically thin transition metal dichalcogenides (TMDCs) are emerging as a new platform for exploring many-body effects. Coulomb interactions are markedly enhanced in these materials because of the reduced dimensionality and large effective masses. Although many-body excitonic effects in TMDCs have been extensively studied by optical means, not until recently did probing their strongly correlated electronic effects become possible in transport. In this talk, I demonstrate our recent experimental study on quantum transport of few-layer WSe2 and MoS2 with unconventional electron Landau levels (LLs) and strong interaction effects. We fabricate high-quality n-type MoS2 and p-type WSe2 devices and study their valley-resolved SdH oscillations relevant to the spin-valley locked massive Dirac electron LLs. Encapsulating these TMDCs in ultra-clean hexagonal boron nitride sheets effectively eliminates impurity scattering and provides clean interfaces for making high-quality low-temperature ohmic contacts. Few-layer WSe2 and MoS2 field-effect devices with mobilities up to 20,000 cm2/V s have been achieved at cryogenic temperatures. We observe interesting quantum Hall transport phenomena involving the Q valley, Γ valley and K valley, such as the Q valley Zeeman effect in all odd-layer MoS2 devices and the spin Zeeman effect in all even-layer MoS2 devices and highly density-dependent quantum Hall states of Γ valley holes below 12T, whose predominant sequences alternate between odd- and even-integers. By tilting the magnetic field to induce Landau level crossings, we show that the strong Coulomb interaction enhances the Zeeman-to-cyclotron energy ratio from 2.67 to 3.55 as the density is reduced from 5.7 to 4.0×1012 cm-2, giving rise to the even-odd alternation. With decreasing the carrier density in the conductance band (K valley) of few-layer MoS2, we observe LL crossing induced valley ferrimagnet-to-ferromagnet transitions, as a result of the interaction enhancement of the g-factor from 5.6 to 21.8. Near integer ratios of Zeeman-to-cyclotron energies, we discover LL anti-crossings. Our results provide compelling evidence for many-body interaction effects in few-layer WSe2 and MoS2.
Speaker Bio: Professor Wang obtained his BSc (1985) and PhD (1990) degrees in materials physics from the University of Science and Technology, Beijing. In 1989, he received an Alexander von Humboldt Research Fellowship and worked in the Institute for Metal Physics, Goettingen University and the Fritz-Haber-Institute of the Max-Planck Society, Berlin, Germany. In 1993, he joined the Physics Department of the Hong Kong University of Science and Technology. During 1997-2000 he worked in the Department of Applied Physics and Materials Science, the City University of Hong Kong. Professor Wang has authored/co-authored 250 peer-reviewed research papers in reputed international journals. He received Chien-Shiung Wu Physics Award (1990), State Natural Science Award (2005), Achievement in Asia Award (2006), and School of Science Service Awards (2015).
IDRE Hosts Structural Equation Modeling (SEM) Training
IDRE is partnering with Stats Camp to bring statistical analysis training to UCLA on Monday, March 26 through Wednesday, March 28 from 9 am to 5 pm. The three-day event is called Structural Equation Modeling (SEM) Foundations and is an advanced intensive short course on the Craft of Structural Equation Models (SEM).
Course topics include:
• Design and measurement issues in cross-sectional and longitudinal research
• Traditional panel designs
• Overview of missing data
• Latent growth curve modeling
• Testing for Mediation and Moderation
• Multilevel and multiple group SEM
• Using Phantom Constructs
• Multiple group modeling
• Three days of training led by Dr. Todd Little, a leading and renowned SEM and longitudinal model researcher
• Training materials in electronic format and access to a video of the seminar
• Catering of breakfast, lunch and snacks
• One-on-One consultation with instructor for your individual research questions
Register on the Stats Camp site with a valid UCLA email and the discount code “UCLAstatscamp” to receive a massive 35% discount on registration fees! Contact IDRE Stats for further information at: email@example.com.
Thursday, March 8 through Saturday, March 10
10 a.m. to 2 p.m.
Ackerman Grand Ballroom
On March 8-10, 2018, IPAM will host a conference showcasing the achievements of Latinx in the mathematical sciences. The goal of the conference is to encourage Latinx to pursue careers in the mathematical sciences, to promote the advancement of Latinx currently in the discipline, to showcase research being conducted by Latinx at the forefront of their fields, and, finally, to build a community around shared academic interests.
The program lies at the juncture of mathematics and theoretical computer science in a quest for quantitative answers to finite-dimensional questions. The program brings together topics from a number of important directions, including discrepancy theory, spectral graph theory, random matrices, geometric group theory, ergodic theory, von Neumann algebras, as well as specific research directions such as the Kadison-Singer problem, the Connes embedding conjecture and the Grothendieck inequality.
A very important aspect of the program is its aim to deepen the link between research communities working on some infinite-dimensional functional analysis problems that occur in geometric group theory, ergodic theory, von Neumann algebras; and some quantitative finite-dimensional ones that occur in spectral graph theory, random matrices, combinatorial optimization, and the Kadison-Singer problem.
The program opens with four days of tutorials that will provide an introduction to major themes of the entire program and the four workshops. The goal is to build a foundation for the participants of this program who have diverse scientific backgrounds. For those participating in the long program, please plan to attend Opening Day on March 19, 2018, as well. Others may participate in Opening Day by invitation from the organizing committee.