Seminars

Seminars From Year 2014

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All seminars will be held in Wu & Chen Auditorium, Levine Hall (3330 Walnut Street) unless otherwise indicated.

  • Talk: GRASP Special Seminar: Jeremy Gillula, University of California at Berkeley, "Guaranteeing Safe Online Machine Learning via Reachability Analysis"
    Date: Thursday, January 16, 2014 - 12pm to 1pm
    Presenters: Jeremy Gillula
    Alternate Location: Moore 317 (inside Moore 316)
    Reinforcement learning has proven itself to be a powerful technique in robotics, however it has rarely been employed to learn in a hardware-in-the-loop environment due to the fact that spurious training data could cause a robot to take an unsafe (and potentially catastrophic) action. We will present a method for overcoming this limitation known as Guaranteed Safe Online Learning via Reachability (GSOLR), in which the control outputs from the reinforcement learning algorithm are wrapped inside another controller based on reachability analysis that seeks to guarantee safety against worst-case disturbances. After defining the relevant backwards reachability constructs and explaining how they can be calculated, we will formalize the concept of GSOLR and show how it can be used on a real-world target tracking problem, in which an observing quadrotor helicopter must keep a target ground vehicle with unknown (but bounded) dynamics inside its field of view at all times, while simultaneously attempting to build a motion model of the target.  Extensions to GSOLR will then be presented, which allow the safety of the system to automatically become neither too liberal nor too conservative, thus allowing the machine learning algorithm running in parallel the widest possible latitude while still guaranteeing system safety. These extensions will be demonstrated on the task of safely learning an altitude controller for a quadrotor helicopter.  These examples demonstrate the GSOLR framework's robustness to errors in machine learning algorithms, and indicate its potential for allowing high-performance machine learning systems to be used in safety-critical situations in the future.
  • Talk: GRASP Special Seminar: Jnaneshwar Das, University of Southern California, "Data-driven Robotic Sampling for Marine Ecosystem Monitoring"
    Date: Friday, January 17, 2014 - 11am to 12pm
    Presenters: Jnaneshwar Das
    Alternate Location: Levine 307 (3330 Walnut Street)
    Robotic sampling is attractive in many field robotics applications that require persistent collection of physical samples for ex-situ analysis. Examples abound in the earth sciences in studies involving the collection of rock, soil, and water samples for lab analysis. The desirability of samples in these domains can be expressed as a property that cannot be determined in-situ, but can be predicted by covariates measurable in real-time using sensors carried aboard a robot. In our test domain, marine ecosystem monitoring, accurate measurement of plankton abundance requires lab analysis of water samples, but predictions using physical and chemical properties measured in real-time by sensors carried aboard an autonomous underwater vehicle (AUV) can guide sample collection decisions. We present a principled approach to minimize cumulative regret of plankton samples acquired by an AUV over multiple surveys in batches of k water samples per survey. Samples are labeled at the end of each survey, and used to update a probabilistic model that guides sampling in subsequent surveys. The problem is formulated in an online setting: given a predetermined survey duration and a probabilistic model learned from earlier surveys, the AUV makes irrevocable sample collection decisions on a sequential stream of candidates, with no knowledge of the future. Our experimental results are based on extensive retrospective studies emulating 100 campaigns, each composed of 17 surveys. The campaigns were emulated by mining historical field data collected by an AUV operating at depths of up to 100 m over a 40 sq. km area in an 8 day period. These studies establish the efficacy of the approach - beginning with no prior, successive surveys by the AUV result in samples that are progressively higher-abundance in a pre-specified type of plankton. Additionally we carried out a one-day field trial with an AUV operating at depths of up to 30 m over a 1 sq. km area. Beginning with a prior learned from data collected and labeled in an earlier campaign, the AUV field survey resulted in samples with a high-abundance of a pre-specified type of plankton - a potentially toxinogenic alga of interest to marine ecologists. This is the first time such a field experiment has been carried out in its entirety in a data-driven fashion, in effect 'closing the loop' on a significant and relevant ecosystem monitoring problem. Although the experimental context for work is marine ecosystem monitoring, it is well-suited for autonomous and persistent robotic observation of any property that cannot be measured in-situ, but possesses observable covariates, thus opening up the potential for advanced autonomous robotic exploration of unstructured environments that are inaccessible to humans.
  • Talk: Spring 2014 GRASP Seminar: Joelle Pineau, McGill University, "Learning Socially Adaptive Navigation Strategies : Lessons from the SmartWheeler Project"
    Date: Friday, January 31, 2014 - 11am to 12pm
    Presenters: Joelle Pineau
    A key skill for mobile robots is the ability to navigate efficiently through their environment. In the case of social or assistive robots, this involves navigating through human crowds. Typical performance criteria, such as reaching the goal using the shortest path, are not appropriate in such environments, where it is more important for the robot to move in a socially acceptable manner. In this talk I will describe new methods based on imitation and reinforcement learning which we have developed to allow robots to achieve socially adaptive path planning in human environments. Performance of these methods will be illustrated using a smart power wheelchair developed in our group, called the SmartWheeler.
  • Talk: Spring 2014 GRASP Seminar: Aaron Dollar, Yale University, "Reengineering the Hand: "Mechanical Intelligence" in Robotic Manipulation"
    Date: Friday, February 7, 2014 - 11am to 12pm
    Presenters: Aaron Dollar
    Despite decades of research, current robotic systems are unable to reliably grasp and manipulate a wide range of unstructured objects in human environments. The somewhat traditional approach of attempting to copy the immense mechanical complexity of the human hand in a stiff "robotic" mechanism, and the subsequently required levels of sensing and control, has not yet been successful. Alternatively, with careful attention to the design of the mechanics of hands, including adaptive underacted transmissions and carefully tuned compliance, we have been able to achieve a level of dexterity and reliability as yet unseen in the robotics community. I will describe ongoing efforts to further develop grasping and dexterous manipulation capabilities in engineered systems as well as our work in studying human hand function to guide some of the efforts.
  • Talk: Spring 2014 GRASP Seminar: Al Rizzi, Boston Dynamics, "Legged Robotics at Boston Dynamics"
    Date: Friday, February 14, 2014 - 11am to 12pm
    Presenters: Alfred Rizzi
    Only about half the Earth's landmass is accessible to wheeled and  tracked vehicles, yet people and animals can go almost everywhere on foot. Our goal is to develop novel locomotion systems that can go anywhere people and animals go. The systems we build combine dynamic control systems, actuated mechanisms and sensing to travel on terrain that is too rocky, sandy, muddy, snowy, wet or steep for existing conventional vehicles. This presentation will discuss progress at Boston Dynamics in building such systems, including WildCat, LS3, Atlas, RHex, PETMAN and others.
  • Talk: MEAM / GRASP Seminar: Matthew Turpin, University of Pennsylvania, "Scalable Trajectory Computation for Large Teams of Interchangeable Robots Applied to Quadrotor MAVs"
    Date: Wednesday, February 19, 2014 - 1pm to 2pm
    Presenters: Matthew Turpin
    Alternate Location: Levine 307 (3330 Walnut Street)
    Large teams of robots have been implemented to great success in Kiva's automated warehouses as well as UPenn's and KMel Robotics' swarms of quadrotors. In settings such as these, robots must plan paths which avoid collisions with other robots and obstacles in the environment. Unfortunately, trajectory planning for large teams of robots generally suffers from either the curse of dimensionality or lack of completeness. I will demonstrate that relaxing the assumption of labeling each robot and specifying a  fixed assignment of robots to destinations in the trajectory generation problem yields a number of computational and performance benefits. My algorithm to solve this Concurrent Assignment and Planning of Trajectories (CAPT) problem has bounded computational complexity of O(N^3), preserves completeness properties of a user specified single agent motion planner, and tends to minimize effort exerted by any one robot. This algorithm generates solutions to variants of the CAPT problem in settings ranging from kinematic robots in an obstacle free environment to teams of robots with 4th order dynamics in a cluttered environment. Finally,  I will show experimental results of the algorithm applied on teams of second order aquatic vehicles as well as on quadrotor micro aerial vehicles. I will also outline how time consuming aspects of this approach can be parallelized and discuss possible decentralized implementations.
  • Talk: CANCELED: Spring 2014 GRASP Seminar: Kris Hauser, Indiana University, "Motion Planning for Real World Robots"
    Date: Friday, February 21, 2014 - 11am to 12pm
    Presenters: Kris Hauser
    Motion planning -- the problem of computing physical actions to complete a specified task -- has inspired some of the most theoretically rigorous and beautiful results in robotics research.  But as robots proliferate in real-world applications like household service, driverless cars, warehouse automation, minimally-invasive surgery, search-and-rescue, and unmanned aerial vehicles, the classical theory appears to have fallen behind the pace of practice.  At odds with the "clean" assumptions of theory, the reality is that robots must handle large amounts of noisy sensor data, uncertainty, underspecified models, nonlinear and hysteretic dynamic effects, exotic objective functions and constraints, and real-time demands.  This talk will describe efforts to bring theory up to speed, in the context of three projects: 1) ladder climbing in the DARPA Robotics Challenge; 2) intelligent user interfaces for human-operated robots; and 3) navigation amongst many moving obstacles.  I will present new planning algorithms and architectures whose performance is backed both by theoretical guarantees and empirical evaluation.
  • Talk: Spring 2014 GRASP Seminar: Ryan Eustice, University of Michigan, "SLAM in the Wild: Robust and Persistent Visual SLAM for Autonomous Underwater Hull Inspection"
    Date: Friday, February 28, 2014 - 11am to 12pm
    Presenters: Ryan Eustice
    The field of simultaneous localization and mapping (SLAM) has made tremendous progress in the last couple of decades, to the point where we have mature-enough methods and algorithms to explore applications on interesting scales both spatially and temporally.  In this talk we discuss some of our current efforts in deploying large-scale, long-term SLAM systems in real-world field applications, and in particular, our current work in autonomous underwater ship hull inspection.  We will discuss our developments in modeling the visual saliency of underwater imagery for pose-graph SLAM, how this saliency measure can be used within an active SLAM planning paradigm, and our development of generic linear constraints---a principled framework for pose-graph reduction, which is important for controlling multi-session SLAM graph complexity.
  • Talk: Spring 2014 GRASP Seminar: Leila Takayama, Google[x], "Designing for the Seemingly Nonsensical Ways People See, Treat, and Use Robots"
    Date: Friday, March 7, 2014 - 11am to 12pm
    Presenters: Leila Takayama
    As robots are entering our everyday lives, it is becoming increasingly important to understand how untrained people will interact with robots. Fortunately, untrained people already interact with a variety of robotic agents (withdrawing cash from ATMs, driving cars with anti-lock brakes) so we are not completely starting from scratch. In the moment of those interactions with robotic agents, people behave in ways that do not necessarily align with the rational belief that robots are just plain machines. Through a combination of controlled experiments and field studies, this talk will examine the ways that untrained people interact with robotic agents, including (1) how we interact with personal robots, and (2) how we interact through telepresence robots. Drawing from theories of human-computer interaction and this type of empirical research, we provide implications for both theory and the design of interactive robotic systems.
  • Talk: GRASP Special Seminar: Sergio Pequito, Carnegie Mellon University, "A Framework for Structural Input/Output and Control Configuration Selection of Large-Scale Systems"
    Date: Thursday, March 13, 2014 - 11am to 12pm
    Presenters: Sérgio Pequito
    Alternate Location: Levine 307 (3330 Walnut Street)
    The structure control system design consists mainly of two steps: input/output (I/O) selection and control configuration (CC) selection. The first one is devoted to the problem of computing how many actuators/sensors are needed and where should be placed in the plant to obtain some desired property. Control configuration is related to the decentralized control problem and is dedicated to the task of selecting which outputs (sensors) should be available for feedback and to which inputs (actuators) in order to achieve a predefined goal. The choice of inputs and outputs affects the performance, complexity and costs of the control system. Due to the combinatorial nature of the selection problem, an efficient and systematic method is required to complement the designer intuition, experience and physical insight. Motivated by the above, this presentation addresses the structure control system design taking explicitly into consideration the possible application to large-scale systems. We provide an efficient framework to solve the following major minimization problems: i) selection of the minimum number of manipulated/measured variables to achieve structural controllability/observability of the system, and ii) selection of the minimum number of measured and manipulated variables, and feedback interconnections between them such that the system has no structural fixed modes. Contrary to what would be expected, we showed that it is possible to obtain the global solution of the aforementioned minimization problems in polynomial complexity in the number of the state variables of the system. To this effect, we propose a methodology that is efficient (polynomial complexity) and unified in the sense that it solves simultaneously the I/O and the CC selection problems. This is done by exploiting the implications of the I/O selection in the solution to the CC problem. An example illustrate the main features of the proposed procedure.
  • Talk: GRASP Special Seminar (Joint Talk): Daigo Muramatsu & Ikuhisa Mitsugami, Osaka University)
    Date: Thursday, March 13, 2014 - 2pm to 3pm
    Presenters: Daigo Muramatsu & Ikuhisa Mitsugami
    Alternate Location: Levine 307
    Presenter: Daigo Muramatsu "Cross-view Gait Recognition" Abstract: Gait recognition is a biometric method used to recognize a person from their walking style, which can be acquired from a camera. Unlike many biometric techniques such as fingerprint, iris or face recognition, gait recognition can authenticate a person some distance from the camera, because it has high accuracy even when the resolution of an image sequence is relatively low. However, the accuracy of gait recognition is often degraded by view difference. In this talk, we focus on the view issue of gait recognition and discuss some solution against accuracy degradation caused by the view difference. ---------------------------------------------------------------------- Presenter: Ikuhisa Mitsugami"3-D Measurement and Analysis of Walking Person by Range Sensing" Abstract: Consumer depth sensors, e.g. Microsoft Kinects, are getting more attention because of their low cost and ability to obtain 3-D measurements. We adopt such depth sensors for gait analysis. In this talk, we introduce some of our achievements. One of the recent achievements is full body reconstruction of a walking person. Since the scene is dynamic, we cannot achieve the full body reconstruction only by merging asynchronous range data of Kinects. We thus propose a synchronization method to virtually obtain depth data at the same moment. We also introduce a new gait feature representation based on range observation. It is basically an extension of an existing silhouette-based feature, but shows promising performance in person authentication task.
  • Talk: GRASP Special Seminar: Hyun Soo Park, Carnegie Mellon University, "Understanding a Social Scene from Social Cameras"
    Date: Friday, March 14, 2014 - 1pm to 2pm
    Presenters: Hyun Soo Park
    Alternate Location: Levine 512
    A social camera is a camera carried or worn by a member of a social group, (e.g., a smartphone camera, a hand-held camcorder, or a wearable camera). These cameras are becoming increasingly immersed in our social lives and closely capture our social activities. In this talk, I argue that social cameras are the ideal sensors for social scene understanding, as they inherit social signals such as the gaze behavior of the people carrying them. I will present a computational representation for social scene understanding from social cameras.  In the first part of my talk, I will show how visible social signals, such as body gestures, gaze directions, or facial expression, can be recovered in 3D from social cameras. This work includes 3D trajectory reconstruction and motion capture from body-mounted cameras. The second part of the talk will focus on analysis on the relationship between the social signals using 3D joint attention. This analysis allows us to predict social gaze behaviors.
  • Talk: Spring 2014 GRASP Seminar: Martial Hebert, Carnegie Mellon University, "Challenges in Semantic Perception for Autonomous Systems"
    Date: Friday, March 21, 2014 - 11am to 12pm
    Presenters: Martial Hebert
    Despite considerable progress in all aspects of machine perception, using machine vision in autonomous systems remains a formidable challenge. This is especially true in applications such as robotics, in which even a small error rate in the perception system can have catastrophic consequences for the overall system. This talk will review a few ideas that could be used to start formalizing the issues revolving around the integrating vision systems. They include a systematic approach to the problem of self-assessment of vision algorithm and predicting quality metrics on the inputs to the vision algorithms, ideas on how to manage multiple hypotheses generated from a vision algorithm rather than relying on a single "hard" decision, and methods for using external (non-visual) domain- and task-dependent information. These ideas will be illustrated with examples of recent vision for scene understanding, depth estimation, and object recognition.
  • Talk: Spring 2014 GRASP Seminar: Stefanie Tellex, Brown University, "Natural Language and Robotics"
    Date: Friday, March 28, 2014 - 11am to 12pm
    Presenters: Stefanie Tellex
    Natural language can be a powerful, flexible way for people to interact with robots.  A particular challenge for designers of embodied robots, in contrast to disembodied methods such as  phone-based information systems, is that natural language understanding systems must map between linguistic elements and aspects of the external world, thereby solving the so-called symbol grounding problem.  This talk describes a probabilistic framework for robust interpretation of grounded natural language, called Generalized Grounding Graphs (G^3).  The G^3 framework leverages the structure of language to define a probabilistic graphical model that maps between elements in the language and aspects of the external world.  It can compose learned word meanings to understand novel commands that may have never been seen during training.  Taking a probabilistic approach enables the robot to employ information-theoretic dialog strategies, asking targeted questions to reduce uncertainty about different parts of a natural language command.  By inverting the model, the robot can generated targeted natural language requests for help from a human partner.  This approach points the way toward more general models of grounded language understanding, which will lead to robots capable of building world models from both linguistic and non-linguistic input, following complex grounded natural language commands, and engaging in fluid, flexible dialog with their human partners.
  • Talk: AMCS/GRASP Seminar: Marty Golubitsky, Ohio State University, "Patterns of Synchrony: From Animal Gaits to Binocular Rivalry"
    Date: Friday, March 28, 2014 - 2pm to 3pm
    Presenters: Marty Golubitsky
    Alternate Location: Towne 337
    This talk will discuss previous work on quadrupedal gaits and recent work on a generalized model for binocular rivalry proposed by Hugh Wilson. Both applications show how rigid phase-shift synchrony in periodic solutions of coupled systems of differential equations can help understand high level collective behavior in the nervous system.  For gaits the symmetries predict unexpected gaits and for binocular rivalry the symmetries predict unexpected percepts.
  • Talk: GRASP Special Seminar: Masaki Ogura, Texas Tech University, "Stability Analysis of Switched Linear Systems with Non-Traditional Switching Signals"
    Date: Monday, April 7, 2014 - 2pm to 3pm
    Presenters: Masaki Ogura
    Alternate Location: Levine 307
    The talk presents my recent research on the stability analysis of switched systems, which are a class of dynamical systems whose dynamics can abruptly change. Examples include the control of systems over unreliable networks or with a failure-prone controller. In this talk I will discuss a fundamental property called stability of switched linear systems. I will in particular focus on the case when switching is modeled by non-traditional stochastic processes, in particular, by non-Markovian processes.
  • Talk: Spring 2014 GRASP Seminar: Andrea Thomaz, Georgia Institute of Technology, "Designing Learning Interactions for Robots"
    Date: Friday, April 11, 2014 - 11am to 12pm
    Presenters: Andrea Thomaz
    In this talk I present recent work from the Socially Intelligent Machines Lab at Georgia Tech. One of the focuses of our lab is on Socially Guided Machine Learning, building robot systems that can learn from everyday human teachers. We look at standard Machine Learning interactions and redesign interfaces and algorithms to support the collection of learning input from naive humans. This talk covers results on building computational models of reciprocal social interactions, high-level task goal learning, low-level skill learning, and active learning interactions using several humanoid robot platforms.
  • Talk: Spring 2014 GRASP Seminar: E. Michael Golda, Navy Sea Systems Command Carderock Division, "A Brief Overview of United States Navy Machinery Automation Challenges"
    Date: Friday, April 18, 2014 - 11am to 12pm
    Presenters: E. Michael Golda
    A large naval warship ship is the most complex structure built by man.  The technology trends over the last 70 years have made automation a necessity for controlling the components, systems, and integrated systems of systems that make up a warship.  The presentation will provide a brief introduction of the ship as a system of systems.  The evolution of the Navy’s automation to intelligent agent-based distributed controls will be described.  In addition, opportunities for educational support and joint research with the Navy opportunities will be discussed.