- talks - lists.cs.princeton.edu

Colloquium Speaker: Cynthia Sung, Today, 3:00pm Bowen 222
by Nicole E. Wagenblast 18 Feb '16

18 Feb '16

Cynthia Sung Computational Tools for Robot Design: A Composition Approach Thursday , February 18th 3:00 PM Bowen Hall Rm 222 As robots become more prevalent in society, they must develop an ability to deal with more diverse situations. This ability entails customizability of not only software intelligence, but also of hardware. However, designing a functional ro-bot remains challenging and often involves many iterations of design and testing even for skilled designers. My goal is to create computational tools for making functional machines, allowing future designers to quickly improvise new hardware in response to unexpected circumstances. In this talk, I will discuss one possible approach to automated design using composition. I will describe our origami-inspired print-and-fold process that allows entire robots to be fabricated within a few hours, and I will demonstrate how foldable modules can be composed together to create foldable mechanisms and robots. The modules are represented parametrically, enabling a small set of mod-ules to describe a wide range of geometries and also allowing geometries to be optimized in a straightforward manner. I will also introduce a tool that we have developed that combines this composition approach with simulations to help human designers of all skill levels to design and fabricate custom functional robots. Cynthia Sung is a Ph.D. candidate in the Computer Science and Artificial Intelli-gence Laboratory at the Massachusetts Institute of Technology (MIT). She received a B.S. in Mechanical Engineering from Rice University in 2011 and an M.S. in Elec-trical Engineering and Computer Science from MIT in 2013. Her research interests include computational design, folding theory, and rapid fabrication, and her cur-rent work focuses on algorithms for synthesis and analysis of engineering designs.

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Colloquium- David Duvenaud, Thursday, Feb 18th, 12:30pm
by Mitra Kelly 17 Feb '16

17 Feb '16

Colloquium Speaker David Duvenaud thursday, Feb 18th, 12:30pm CS 105 Talk title: Composing differentiable procedures for modeling, inference, and optimization Talk abstract: Much recent success in machine learning has been through optimizing simple feedforward procedures, such as neural networks, using gradients. Surprisingly, many complex procedures such as message passing, filtering, inference, and even optimization itself can be meaningfully differentiated though as well. Composing these procedures lets us build sophisticated models that generalize existing methods but retain their good properties. We'll show applications to chemical design, gradient-based tuning of optimization procedures, and training procedures that don't require cross-validation. Bio: David Duvenaud is a postdoc in the Harvard Intelligent Probabilistic Systems group, working with Prof. Ryan Adams on model-based optimization, synthetic chemistry, and neural networks. He did his Ph.D. at the University of Cambridge with Carl Rasmussen and Zoubin Ghahramani. Previous to that, he worked on machine vision both with Kevin Murphy at the University of British Columbia, and later at Google Research. David also co-founded Invenia, an energy forecasting and trading firm Mitra Kelly Academic Secretary Princeton University Computer Science Dept 35 Olden Street Princeton NJ 08540 mkelly(a)cs.princeton.edu 609-258-4562

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Allison Chaney will present her Pre-FPO on Wednesday, February 24, 2016 at 1:30pm in Room CS 302.
by Nicki Gotsis 17 Feb '16

17 Feb '16

Allison Chaney will present her Pre-FPO on Wednesday, February 24, 2016 at 1:30pm in Room CS 302. The members of her committee are: David Blei (advisor, reader), Barbara Engelhardt (reader), Brandon Stewart (Sociology), and Elad Hazan Everyone is invited to attend her talk. The talk title and abstract follow below: Title: A Bayesian Model for Detecting and Characterizing Events Social scientists, such as historians and political scientists, commonly read large quantities of text to construct an accurate picture of who, what, when, and where an event happened. In this talk, I will present a Bayesian model for analyzing documents to identify and characterize events of potential significance, where events are characterized by interactions between entities (e.g., countries, organizations, individuals) that deviate from typical interaction patterns. Specifically, the model builds on topic modeling to distinguish between topics that describe “business-as-usual” and topics that deviate from these patterns. I will also describe details of approximate posterior inference for this model as well as visualization and evaluation of the results. This talk includes ongoing work.

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Fwd: EE Department Seminar - Hamed Hassani- February 25, 2016
by Jennifer Rexford 17 Feb '16

17 Feb '16

> > Speaker: > Hamed Hassani, ETH Zurich > Title: > From Communication to Sensing and Learning: Information Theory at the Heart of Data Science > > Day: > Thursday, February 25, 2016 > > > Time: > 4:30 pm > Room: > B205, E-Quad > Host: > Prof. Mung Chiang > > > > > > > > > > Abstract: > We are witnessing a new era of science — ushered in by our ability to collect massive amounts of data and unprecedented ways to learn about the physical world. Beyond the challenges of storage and communication, there are new frontiers in the acquisition, analysis and exploration of the data. In this talk, I will view these frontiers through the lens of information theory. I will argue that information theory lies at the center of data science, offering insights beyond its classical applications. As a concrete example, I will consider the problem of optimal data acquisition, a challenge which arises in active learning, optimal sensing and experimental design. Based on information theoretic foundations, and equipped with tools from submodular optimization theory, I will present a rigorous analysis of the widely-used sequential information maximization policy (also known as the information-gain heuristic). Our analysis establishes conditions under which this policy provably works near-optimally and identifies situations where the policy fails. In the latter case, our framework suggests novel, efficient surrogate objectives and algorithms that outperform classical techniques. > > Bio: > Hamed Hassani is a post-doctoral scholar at the Institute for Machine Learning at ETH Zurich. He received a Ph.D. degree in Computer and Communication Sciences from EPFL, Lausanne. Prior to that, he received a B.Sc. degree in Electrical Engineering and a B.Sc. degree in Mathematics from Sharif University of Technology, Tehran. Hamed's fields of interest include machine learning, coding and information theory as well as theory and applications of graphical models. He is the recipient of the 2014 IEEE Information Theory Society Thomas M. Cover Dissertation Award. His co-authored paper at NIPS 2015 was selected for an oral (plenary) presentation, and his co-authored paper at ISIT 2015 received the IEEE Jack Keil Wolf ISIT Student Paper Award. > >

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Colloquium Speaker: Cynthia Sung, Thursday, February 18, 3:00pm Bowen 222
by Nicole E. Wagenblast 16 Feb '16

16 Feb '16

Cynthia Sung Computational Tools for Robot Design: A Composition Approach Thursday , February 18th 3:00 PM Bowen Hall Rm 222 As robots become more prevalent in society, they must develop an ability to deal with more diverse situations. This ability entails customizability of not only software intelligence, but also of hardware. However, designing a functional ro-bot remains challenging and often involves many iterations of design and testing even for skilled designers. My goal is to create computational tools for making functional machines, allowing future designers to quickly improvise new hardware in response to unexpected circumstances. In this talk, I will discuss one possible approach to automated design using composition. I will describe our origami-inspired print-and-fold process that allows entire robots to be fabricated within a few hours, and I will demonstrate how foldable modules can be composed together to create foldable mechanisms and robots. The modules are represented parametrically, enabling a small set of mod-ules to describe a wide range of geometries and also allowing geometries to be optimized in a straightforward manner. I will also introduce a tool that we have developed that combines this composition approach with simulations to help human designers of all skill levels to design and fabricate custom functional robots. Cynthia Sung is a Ph.D. candidate in the Computer Science and Artificial Intelli-gence Laboratory at the Massachusetts Institute of Technology (MIT). She received a B.S. in Mechanical Engineering from Rice University in 2011 and an M.S. in Elec-trical Engineering and Computer Science from MIT in 2013. Her research interests include computational design, folding theory, and rapid fabrication, and her cur-rent work focuses on algorithms for synthesis and analysis of engineering designs.

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Colloquium Speaker Anirudha Majumdar today, 3:00pm Bowen 222
by Nicole E. Wagenblast 16 Feb '16

16 Feb '16

Anirudha Majumdar Control of agile robots in complex environments with formal safety guarantees Tuesday, February 16th ( Today ) 3:00 PM Bowen Hall Rm 222 The goal of my research is to develop algorithmic and theoretical techniques that push highly agile robotic systems to the brink of their hardware limits while guaranteeing that they operate in a safe manner despite uncertainty in the environment and dynamics.In this talk, I will describe my work on algorithms for the synthesis of feedback controllers that come with associated formal guarantees on the stability of the robot and show how these control-lers and certificates of stability can be used for robust planning in environments previously un-seen by the system. In order to make these results possible, my work connects deeply to compu-tational tools such as sums-of-squares (SOS) programming and semidefinite programming from the theory of mathematical optimization, along with approaches from nonlinear control theory.I will describe this work in the context of the problem of high-speed unmanned aerial vehicle (UAV) flight through cluttered environments previously unseen by the robot. In this context, the tools I have developed allow us to guarantee that the robot will fly through its environment in a collision-free manner despite uncertainty in the dynamics (e.g., wind gusts or modeling errors). The resulting hardware demonstrations on a fixed-wing airplane constitute one of the first exam-ples of provably safe and robust control for robotic systems with complex nonlinear dynamics that need to plan in realtime in environments with complex geometric constraints. Anirudha Majumdar is a Ph.D. candidate in the Electrical Engineering and Computer Science de-partment at MIT. He is a member of the Robot Locomotion Group at the Computer Science and Artificial Intelligence Lab and is advised by Prof. Russ Tedrake. Ani received his undergraduate degree in Mechanical Engineering and Mathematics from the University of Pennsylvania, where he was a member of the GRASP lab. His research is primarily in robotics: he works on algorithms for controlling highly dynamics robots such as unmanned aerial vehicles with formal guarantees on the safety of the system. Ani's research has been recognized by the Siebel Foundation Scholar-ship and the Best Conference Paper Award at the International Conference on Robotics and Auto-mation (ICRA) 2013.

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Anirudha Majumdar talk TODAY
by Mitra Kelly 16 Feb '16

16 Feb '16

Anirudha Majumdar Control of agile robots in complex environments with formal safety guarantees Tuesday, February 16th (Today) 3:00 PM Bowen Hall Rm 222 The goal of my research is to develop algorithmic and theoretical techniques that push highly agile robotic systems to the brink of their hardware limits while guaranteeing that they operate in a safe manner despite uncertainty in the environment and dynamics. In this talk, I will describe my work on algorithms for the synthesis of feedback controllers that come with associated formal guarantees on the stability of the robot and show how these control-lers and certificates of stability can be used for robust planning in environments previously un-seen by the system. In order to make these results possible, my work connects deeply to compu-tational tools such as sums-of-squares (SOS) programming and semidefinite programming from the theory of mathematical optimization, along with approaches from nonlinear control theory. I will describe this work in the context of the problem of high-speed unmanned aerial vehicle (UAV) flight through cluttered environments previously unseen by the robot. In this context, the tools I have developed allow us to guarantee that the robot will fly through its environment in a collision-free manner despite uncertainty in the dynamics (e.g., wind gusts or modeling errors). The resulting hardware demonstrations on a fixed-wing airplane constitute one of the first exam-ples of provably safe and robust control for robotic systems with complex nonlinear dynamics that need to plan in realtime in environments with complex geometric constraints. Anirudha Majumdar is a Ph.D. candidate in the Electrical Engineering and Computer Science de-partment at MIT. He is a member of the Robot Locomotion Group at the Computer Science and Artificial Intelligence Lab and is advised by Prof. Russ Tedrake. Ani received his undergraduate degree in Mechanical Engineering and Mathematics from the University of Pennsylvania, where he was a member of the GRASP lab. His research is primarily in robotics: he works on algorithms for controlling highly dynamics robots such as unmanned aerial vehicles with formal guarantees on the safety of the system. Ani's research has been recognized by the Siebel Foundation Scholar-ship and the Best Conference Paper Award at the International Conference on Robotics and Auto-mation (ICRA) 2013. Mitra Kelly Academic Secretary Princeton University Computer Science Dept 35 Olden Street Princeton NJ 08540 mkelly(a)cs.princeton.edu 609-258-4562

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Colloquium Speaker David Chu, Monday, Feb 15, 12:30pm
by Mitra Kelly 15 Feb '16

15 Feb '16

Colloquium Speaker David Chu, MSR Monday, Feb 15th, 12:30pm Room CS 105 Title: In Pursuit of Low-Latency Interactions on Mobile Devices Abstract: Human attention is a scarce resource, but when available, it can also be wonderfully perceptive. My research seeks to understand: what does it take for mobile devices --- power-constrained as they are --- to operate at the speed of human perception? And what new opportunities emerge as a result? Via a pair of vignettes, I illustrate two such low-latency mobile systems. The first focuses on app streaming, an emerging app execution model in which remote servers execute logic and rendering on behalf of thin clients. App streaming promises any device access to any app at any time. Unfortunately, the reality is that wide-area network latencies often exceed thresholds above which many interactive apps such as games tend to be deemed too slow. In response, I describe Outatime, a speculative execution system for app streaming that masks network latency. In Outatime, the server renders speculative frames of future possible outcomes, delivering them to the client one entire roundtrip early, and recovers quickly from mis-speculations when they occur. Clients perceive little latency. Outatime has been implemented on two high-quality, commercially-released twitch-based games. Users report strongly preferring Outatime to standard streaming, since Outatime delivers real-time interactivity as fast as --- and in some cases, even faster than --- traditional local client-side execution. In a second example of low-latency interaction, I describe a Kinect-like device tracking system, FAR. Unlike Kinect, FAR is portable, requiring only the phones in our hands. Yet FAR performs continuous, fast and accurate phone-to-phone localization that matches the (often very fast) speed and sensitivity of human movement. In fact, FAR's accuracy is comparable to --- and in some cases, even superior to --- that of Kinect. Lab trials and many real world deployments indicate that FAR can fully support dynamic human motion in real-time. Bio: David Chu is a researcher in Microsoft's Mobility and Networking Research Group. His research interests are in mobile systems and applications, cyber-physical systems, sensing systems, ubiquitous computing and applied machine learning. The main thrust of David's current work is toward low-latency perception-aligned mobile systems. He received the Best Paper award in MobiSys 2015, the Best Paper nomination in MobiSys 2012, the Best Demo award in MobiSys 2014, and the Best Demo nomination in SenSys 2011. David's research has appeared on multiple occasions in tech news such as TechCrunch, PC Magazine, GameSpot, Ars Technia, Slashdot, The Verge, Engadget and Wired. At Microsoft, David has contributed to Windows and Windows Phone, Xbox and HoloLens. David received his B.S. from the University of Virginia in 2004; and his M.S. and Ph.D. from the University of California, Berkeley in 2005 and 2009, respectively, while an NSF Graduate Research Fellow. Mitra Kelly Academic Secretary Princeton University Computer Science Dept 35 Olden Street Princeton NJ 08540 mkelly(a)cs.princeton.edu 609-258-4562

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TODAY: Physics Colloquium, 4:30 p.m. Thurs. Feb. 11; Sebastian Seung (Princeton), “Structure and function of the retina,” Jadwin A-10
by Nicole E. Wagenblast 11 Feb '16

11 Feb '16

Princeton University Department of Physics Hamilton Colloquium Series Speaker: Sebastian Seung Neuroscience Institute and Computer Science Department Princeton University “Structure and function of the retina” The importance of determining and interpreting the structures of atoms, crystals, and proteins was established long ago. I will discuss current efforts to extend this paradigm to the brain, focusing on new discoveries concerning the structure of the retina gained through 3D electron microscopy, computer vision, and crowdsourcing. I will also describe how such structural information is helpful for understanding how the retina carries out the first steps of visual perception. 4:30 p.m., Thursday, February 11, 2016 Jadwin Hall, Room A-10 Host: N. Phuan Ong , Princeton University Tea at 4 p.m., Lounge Area outside Jadwin A-10

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Katherine Edwards will present her Pre-FPO on Tuesday, February 16, 2016 at 11am in CS 302.
by Nicki Gotsis 10 Feb '16

10 Feb '16

Katherine Edwards will present her Pre-FPO on Tuesday, February 16, 2016 at 11am in CS 302. The members of her committee are: Paul Seymour (advisor), Maria Chudnovsky and Chun-Hung Liu; (readers - Math Dept) and Bernard Chazelle and Bob Tarjan (non-readers). Everyone is invited to attend her talk. The talk title and abstract follow below: Title: A collection of results in graph theory In this thesis, we present several results in graph theory. In this talk, we will highlight four of them. First, we discuss two results about edge colouring. In 1966 Tutte conjectured that every two-connected cubic graph without the Petersen graph as a minor is three-edge colourable. This statement generalizes the celebrated four-colour theorem. In previous work, Seymour et al. showed that to prove Tutte’s conjecture, it is sufficient to prove it for apex graphs (graphs which can be made planar by deleting a vertex) and doublecross graphs (graphs which can be drawn in the plane with just two crossings, in the infinite region). Sanders and Thomas recently solved the apex case. With Sanders, Seymour and Thomas, we give a proof for the doublecross case. Seymour conjectured in 1973 that every k-regular planar graph can be k-edge-coloured if and only if for every odd subset X of vertices, there are at least k edges between X and its complement. When k=3, this is the statement of the Four Colour theorem, and the conjecture had been proved for values of k up to 7. In joint work with Chudnovsky, Kawarabayashi and Seymour we give a proof for the case k=8 and a new, simpler proof for the case k=7. Next, we will consider fractional vertex colourings of graphs not containing large cliques. Fractional colouring is a generalization of graph colouring in which vertices are assigned sets of colours so that every pair of adjacent vertices receive disjoint sets. The fractional chromatic number is bounded above by the maximum degree \Delta, but in graphs which do not contain a clique of size Delta we can generally find stronger upper bounds. We will discuss some progress, joint with King, in bounding the fractional chromatic number of K_\Delta -free graphs away from \Delta. Our method relies on a local strengthening of the fractional relaxation of Reed's \omega, \Delta, \chi conjecture which roughly stipulates that if a graph has high fractional chromatic number then it must contain a vertex of high degree and a large clique in the same local area of the graph. We have also obtained new, stronger local bounds on the fractional chromatic number. Finally, we discuss some work with applications in large graph analytics. The hyperbolicity of a graph is an invariant which roughly measures the hyperbolicity of the metric space induced by its associated distance metric. Many real-world networks have been shown experimentally to have a small hyperbolicity constant. Such graphs also tend to be so large that superlinear-time algorithms are highly impractical, so it is interesting to design fast approximation algorithms for optimization problems on graphs with a fixed hyperbolicity. We investigate the $p$-centre problem, a popular clustering technique wherein we seek to locate $p$ centres on the graph for which the maximum distance from a vertex to its closest centre (this distance is called the $p$-radius $r_p$) is minimized. With Kennedy and Saniee, we give a combinatorial linear-time approximation algorithm to determine $p$-centers with an additive error on $r_p$ of at most 3 times its hyperbolic constant. This improves on the previously best-known quadratic time algorithm.

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