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JOAO PEDRO HESPANHA @ UCSB |
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Professor Associate director Executive committee member |
Email: hespanha @ ece.ucsb.edu Postal address: |
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| Brief Bio |
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João P. Hespanha was born in Coimbra, Portugal, in 1968. He received the Licenciatura in electrical and computer engineering from the Instituto Superior Técnico, Lisbon, Portugal in 1991 and the Ph.D. degree in electrical engineering and applied science from Yale University, New Haven, Connecticut in 1998. From 1999 to 2001, he was Assistant Professor at the University of Southern California, Los Angeles. He moved to the University of California, Santa Barbara in 2002, where he currently holds a Professor position with the Department of Electrical and Computer Engineering. Prof. Hespanha is Associate Director for the Center for Control, Dynamical-systems, and Computation (CCDC), Vice-Chair of the Department of Electrical and Computer Engineering, and a member of the Executive Committee for the Institute for Collaborative Biotechnologies (ICB). From 2004—2007 he was an associate editor for the IEEE Transactions on Automatic Control. His current research interests include hybrid and switched systems; the modeling and control of communication networks; distributed control over communication networks (also known as networked control systems); the use of vision in feedback control; and stochastic modeling in biology. Dr. Hespanha is the recipient of the Yale University’s Henry Prentiss Becton Graduate Prize for exceptional achievement in research in Engineering and Applied Science, a National Science Foundation CAREER Award, the 2005 best paper award at the 2nd Int. Conf. on Intelligent Sensing and Information Processing, the 2005 Automatica Theory/Methodology best paper prize, and the 2006 George S. Axelby Outstanding Paper Award. Dr. Hespanha is a Fellow of the IEEE and an IEEE distinguished lecturer since 2007. Detailed curriculum vitae |
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HYBRID SYSTEMS As computers, digital networks, and embedded systems become ubiquitous and increasingly complex, one needs to understand the coupling between logic-based components and continuous physical systems. This prompted a shift in the standard control paradigm — in which dynamical systems were typically described by differential or difference equations — to allow the modeling, analysis, and design of systems that combine continuous dynamics with discrete logic. This new paradigm is often called hybrid, impulsive, or switched control.
Good starting points to learn about hybrid control systems include
Our research covers several aspects of hybrid/switched systems:
Publications on this work can be found at the following
URL: While some of our work on hybrid systems is of a theoretical nature, it is motivated by several high-impact application areas, including networked control systems, cooperative control of autonomous systems, communication networks, and systems biology. Details on some of these application areas are included below. | ||||||||||||||
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NETWORKED CONTROL SYSTEMS (NCSs) Network Control Systems (NCSs) are spatially distributed systems in which the communication between sensors, actuators and controllers occurs through a shared band-limited digital communication network. The use of a multi-purpose shared network to connect spatially distributed elements results in flexible architectures and generally reduces installation and maintenance costs. Consequently, NCSs have been finding application in a broad range of areas such as the automotive and aerospace industries, mobile sensor networks, remote surgery, automated highway systems, and unmanned aerial vehicles.
The interest in NCSs has been steadily rising due to several factors:
Inexpensive computation and ubiquitous embedded sensing, actuation, and communication provide tremendous opportunities for societal impact, but also great challenges in the design of networked control systems, because the traditional unity feedback loop that operates in continuous time or at a fixed sampling rate is not adequate when sensor data arrives from multiple sources, asynchronously, delayed, and possibly corrupted. Moreover, the design of NCSs poses novel questions that lie at the intersection of control, communication, and signal processing:
Our research on NCSs is motivated by the following observations:
A good starting point to learn about the design of controllers for NCSs is the following survey: J. Hespanha, P. Naghshtabrizi, Y. Xu. A Survey of Recent Results in Networked Control Systems. Proc. of IEEE Special Issue on Technology of Networked Control Systems, 95(1):138—162, Jan. 2007. [bibtex] [pdf] Publications on this work can be found at the following URL: | ||||||||||||||
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COOPERATIVE CONTROL OF AUTONOMOUS AGENTS Robotic agents have the potential to free humans from unpleasant, dangerous, and/or repetitive tasks in which human performance would degrade over time due to fatigue. Currently, assembly lines for the automotive industry are highly automated using robots for welding, painting, machine loading, parts transfer and assembly, etc. However, these robotic systems have little autonomy and essentially continuously execute preprogrammed motions with little cognition of their surroundings. The expression autonomous agents refers to the control of ground, aerial or aquatic robots so as to perform tasks that require a significant amount of information gathering, data processing, and decision making, without explicit human control. Especially promising (and challenging) is the use of groups of robots to perform complex tasks in a cooperative fashion. These tasks include:
The interest in this area sparked in the last few years because of two main factors:
Two key technical challenges in this area have driven our research:
Publications on this work can be found at the following URLs: | ||||||||||||||
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ADVANCED SENSING AND ACTUATION The emergence of novel sensor and actuator suites are creating significant opportunities (and challenges!) for control engineers. From the actuation side, advances in materials and fabrication techniques are resulting in high-torque/low-power/low-weight electric motors at a low cost. Micro-Electro-Mechanical Systems (MEMS, which result from the integration of mechanical elements and electronics on a common silicon substrate) and smart materials (i.e., materials whose properties can be significantly changed in a controlled fashion by external stimuli, such as stress, temperature, moisture, pH, electric or magnetic fields) are also starting to be used for very low-power and high-efficiency mechanical actuators.
MEMS technology is also revolutionizing sensing, especially for what regards small, low-power, low-cost sensors for navigation. Imaging is another sensing technology with growing importance. Imaging is especially attractive because it is passive, non-contact, very versatile, and low-cost. However, it introduces several technical challenges:
The key driving force behind our research in this area is the need to develop control algorithms for systems with advanced sensors and actuators that overcome the following challenges:
Publications on the use of imaging sensors in control can
be found at the following URL: | ||||||||||||||
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SYSTEMS BIOLOGY Systems biology seeks to understand living organisms by modeling and analyzing the complex interactions of genes, proteins, and other cell elements. These interactions occur through biochemical reactions that take place inside the cell or close to the cell membrane. Particularly crucial are the chemical reactions that participate in the complex regulatory mechanism that control cell functions such as the heat shock response, which protects a cell against environmental stresses (heat, cold, oxygen deprivation, etc.); apoptosis, which leads to a programmed cell death with minimal harm to nearby cells; chemotaxis, which permits a cell to move in search of food or to flee from poisons; or cell division, which results in two daughter cells from a single parent cell. Ultimately, the goal of systems biology is to transform the methodology used for drug discovery, which is currently dominated by mass experimentation. By enlarge, when faced with a new disease or condition, drug developers expose compromised cell cultures to a large number of chemical compounds in the hope of finding a substance that "treats" the disease. Finding such a substance, triggers a second phase of experiments aimed at making sure that this substance does not harm individual cells or organs. In addition, a mechanism must be found to deliver the treatment to the right cells. The goal of systems biology is to guide this effort so that most effort is spent searching among the most promising types of substances and making sure that all cell functions that could be affected by the potential treatment are not negatively affected. What makes finding cures for diseases especially challenging is the fact that cells are exquisitely regulated mechanisms with multiple feedback loops. Suppose for example that it is discovered that a particular disease develops because a set of cells is lacking protein X. A naive cure would be to inject X into the blood stream in an attempt to increase its concentration. However, this can actually have a completely opposite effect if the body interprets the high concentration of X in the blood as a signal that this protein is being overproduced and shuts down the natural production of X. This is not unlike the apparent paradox that results from placing a heater next to the temperature feedback sensor of a central heating systems and suddenly realizing that the whole building got much colder.
The goal of our research has been to develop tools to analyze complex networks of biochemical reactions. Motivated by the above observations, we are especially interested in constructing dynamical models that highlight the feedback mechanisms in cell regulation and that provide a qualitative and quantitative understanding of how the different genes, proteins, and other cell elements contribute to the observed behavior (phenotype). Gene regulatory mechanisms typically involve a large number of distinct chemical species, but it is common for some of these species to be represented by just a few molecules, which can invalidate models based on the deterministic chemical rate equation. Our work has been using tools developed for Stochastic Hybrid Systems to construct differential equations that accurately model the stochastic effects present in biochemical networks.
Publications on this work can be found at the following
URL: Software to compute moment dynamics can be found at the
following URL: | ||||||||||||||
| Courses |
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CURRENTLY none |
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IN THE NEAR FUTURE
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PAST
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| Recent talks & events |
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TALKS Stochastic Hybrid Systems: Modeling, analysis, and applications to networks and biology” Electrical Engineering and Computer Science Seminar, UC Berkeley, May 1, 2006. [slides] Internet Routing Games” Invited talk at the Workshop on Learning and Information in Games and Control, California Institute of Technology, Mar. 22, 2006. [slides] Stochastic Modeling of Chemical Reactions (and more…),” UC Santa Barbara Theoretical Ecology Seminar, Mar. 17, 2006. [slides] Game theoretical approaches to secure and robust routing,” UC Berkeley Seminar, Apr. 22, 2005. [slides] Stochastic hybrid systems: Applications to communications networks,” 43th CDC Workshop, Paradise Island, Bahamas, Dec. 13, 2004. [slides] Communication constraints and latency in Networked Control Systems”, UC Riverside Seminar, Nov. 15, 2004. [slides] Switched Systems: Mixing Logic with Differential Equations. Plenary talk for Controlo 2002, 5th Portuguese Conference on Automatic Control, University of Aveiro, September 5-7, 2002 [slides]. |
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CONFERENCES AND WORKSHOPS Course on Modeling Analysis and Design of Hybrid Control Systems at the HYCON Graduate School on Control from the European Embedded Control Institute, February 12-16, 2007. Trajectory-Tracking, Path-Following, and Formation Control of Autonomous Vehicles. Workshop for the 45th IEEE Conference on Decision and Control, San Diego, CA, December 12, 2006. Hybrid Systems Biology. Workshop for the 45th IEEE Conference on Decision and Control, San Diego, CA, December 12, 2006. 12th Southern California Non-linear Control Workshop. Santa Barbara, California, June 2, 2006. 9th International Workshop on Hybrid Systems: Computation and Control (HSCC 2006), Santa Barbara, California, from March 29--31, 2006. Summer Study in Brazil: US undergraduate and graduate students at UCSB may apply for summer study in Brazil. The program consists of 6 weeks of study in language and applied mathematics in Rio de Janeiro, followed by a 8-10 week project in Campinas (near Sao Paolo). Funding for travel and local expenses is provided through the FIPSE program. More details at http://www.cds.caltech.edu/~murray/cdsa/. Stochastic Hybrid Systems: Theory and Applications. Workshop for the 43rd IEEE Conference on Decision and Control, December 13, 2004. SensorNets@UCSB Spring’04 Mini-Symposium, Bldg 406 conference room, 9-12:30noon, May 17, 2004. 8th Southern California Non-linear Control Workshop. Santa Barbara, California, May 7-8, 2004. 4th Southern California Non-linear Control Workshop. Santa Barbara, California, May 31—June 1, 2002. Modeling and control of Large-scale distributed systems. Winter 2002 seminar series. Logic-based Control. Tutorial session for the 10th Mediterranean Conference on Control and Automation, Lisbon, Portugal, July 9-12, 2002. Control Using Logic and Switching. Tutorial workshop for the 40th IEEE Conference on Decision and Control in Orlando, Florida, December 4-7, 2001. Touch in Virtual Environments. One-day conference on Haptics sponsored by the Integrated Media Systems Center and the Annenberg School for Communication, University of Southern California, Los Angeles, February 23, 2001. Unmanned Air Vehicles: Coordination, Sensing, and Control. Tutorial workshop for the 38th Conference on Decision and Control in Phoenix, Arizona, December 7-9, 1999 and also for the IEEE International Conference on Control Applications/IEEE International Symposium on Computer-Aided Control Systems Design, Anchorage Hilton, Anchorage, Alaska, September 25-27, 2000. System Theory on the Eve of the 21st Century. Mini-course on state-of-the-art topics on system theory by top experts in the field, Arrábida Courses Summer University, Monastery of Arrábida, Arrábida, Portugal, June 28th - July 3rd, 1999. |
| Students, Postdocs, and Visitors |
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PROSPECTIVE STUDENTS Look at this page. |
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CURRENT STUDENTS Abhyudai Singh, BT in Mechanical Engineering (Indian Institute of Technology, Kaput), started PhD in Fall 2004. Shaunak Bopardikar, BT/MT in Mechanical Engineering 2004 (Indian Institute of Technology, Bombay), started PhD in Fall 2005 (co-advised with Prof. Francesco Bullo). Alexandre Mesquita, Undergraduate Degree in Electrical Engineering 2006 (Divisão de Engenharia Eletrônica, Instituto Tecnológico de Aeronáutica - ITA), started PhD in Fall 2006. William (Josh) Russell, started PhD in Fall 2007. Jason Isaacs, started PhD in Fall 2007. |
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FORMER STUDENTS James Riehl, PhD 2007, BS in Engineering 2002 (Harvey Mudd College), currently Systems Design Engineer Specialist, AT&T Government Solutions, Inc. (as of Oct.2007). Payam Naghshtabrizi, PhD 2007, BS in Electrical Engineering 1997 (Sharif University of Technology, Tehran, Iran), currently at Ford Motor Company (as of Oct.~2007). Prabir Barooah, PhD 2007, BT 1996 (Indian Institute of Technology, Kanpur), currently Assistant Professor at the Department of Mechanical Engineering, University of Florida, Gainsville (as of Sep 2007). Chansook Lim, PhD 2006, BS (Seoul National University, Korea), currently Assistant Professor at the Department of Computer Science Hongik University, Korea (as of Feb. 2007) Yonggang Xu, PhD 2006, BS 1998 (Tsinghua University, Beijing, China), currently Senior Control Engineer at Advertising.com, Mountain View, CA, USA (as of Apr. 2006) Junsoo Lee, PhD 2004, BS 1990 (Seoul National University, Korea), currently Assistant Professor at the Department of Computer Science Sookmyung Women's University, Korea (as of Apr. 2006) Hakan Kizilocak, PhD 2004, currently Associate Scientist at Intelligent Optical Systems, Inc., Torrance, CA, USA (as of Oct. 2005) |
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CURRENT POSTDOCS Shengxian, PhD 2007 (University of Illinois, Urbana Champaign). |
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FORMER POSTDOCS Pedro Aguiar, 2002—2005 (Adjunct Professor at the Instituto Superior Técnico, Portugal, as of July 2007). Vladimir Dobrokhodov, 2004—2005 (Research Associate Professor at the Department of Mechanical and Astronautical Engineering, Naval Postgraduate School, Monterey, California, USA, as of Dec. 2005). Jongrae Kim, 2002—2004 (Lecturer/Assistant Professor at the Aerospace Department of the University of Glasgow, UK, as of July 2007). |
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CURRENT AND FUTURE VISITORS This list only contains visitors that will stay at UCSB for 2 weeks or longer (list sorted by date of last arrival) Duarte Antunes, PhD student, Inst. Superior Técnico, Lisbon, Portugal, 8/20/07-12/20/07 and 4/4/08-6/28/08 Prof. Kenji Hirata, Dept. of Mechanical Engineering, Nagaoka University of Technology, Japan, 9/1/08-8/31/09. |
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PAST VISITORS This list only contains visitors that stayed at UCSB for 2 weeks or longer (list sorted by date of last departure) Prof. Ti-Chung Lee, EE dept., Minghsin Univ. of Science & Tech, Taiwan, 8/3/06-8/24/06 and 7/13/07-8/3/07 Hege Sande, PhD student, Norwegian University of Science and Technology, 1/1/07-6/1/07 Paolo Santesso, PhD student, Padova Univ., Italy, 9/1/06-5/31/07 Prof. Nathan Van de Wouw, Eindhoven Univ. of Technology, Netherlands, 10/01/06-2/1/07 Prof. David Angeli, University of Firenze, Italy, 11/18/06-12/3/06 Aksel Andreas Transeth, PhD student, NTNU in Trondheim, Norway, 10/1/06-12/1/06 José Pedro Gaivão, PhD student, Porto Univ., Portugal, 8/4/06-11/1/06 |
| Information for visitors |
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LODGING Lodging information can be found in this page. |
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DIRECTIONS TO UCSB From Los Angeles take the 101N and take the UCSB/Highway 217 exit a few miles after Santa Barbara. At the main gate get a parking permit and directions to the nearest parking lot. My office is in Harold Frank Hall (former Engineering I), 5th floor. You can get the campus map from this page (the main gate is at D6 and Harold Frank Hall/Engineering I is at E5) and a map of the Goleta area (showing the 101 and the 217) from this page . More information can be found at UCSB's visitor center page. Use http://maps.google.com/ to find directions to UCSB. Use the following address for UCSB: Harold Frank Hall UCSB, Santa Barbara, CA 93106 @34.414,-119.841 Google maps has a pretty good resolution in the Santa Barbara area. Click on the link above to see a satellite image of my building. |
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FOOD & FUN in SANTA BARBARA I compiled a list of Santa Barbara restaurants and bars that I like. You can get it from this page. |
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My Erdös number is 4 (one of the paths is given in the table below). If you do not know what this means you may look it up at http://www.oakland.edu/enp/. However, it is not that interesting anyway.
Useful links (too many and outdated, I know...) ECE's webmail, mail server, gmail. UCSB's corporate time server My public DSA key. |
| My free/busy time :-< |