Prof. Emanuele Severino

When : Thursday, December 31, 2009 - 16:30
Speaker : Prof. Emanuele Severino
Affiliation : Università Vita-Salute San Raffaele
Where : Aula Magna 'A. Lepschy'

Abstract :

Date e Title to be announced

Gallium Nitride: The next dominant semiconductor after Silicon

When : Friday, September 25, 2009 - 17:00
Speaker : Prof. Umesh K. Mishra
Affiliation : University of California, Santa Barbara
Where : Aula Magna A. Lepschy

Abstract :

Short bio: Umesh K. Mishra (Fellow, IEEE) received the B.Tech. from the Indian Institute of Technology (IIT) Kanpur, India, in 1979, the M.S. degree from Lehigh University, Bethlehem, PA, in 1980, and the Ph.D. degree from Cornell University, Ithaca, NY, in 1984, all in electrical engineering. He has been with various laboratory and academic institutions, including Hughes Research Laboratories, Malibu, CA, The University of Michigan at Ann Arbor, and General Electric, Syracuse, NY, where he has made major contributions to the development of AlInAsGaInAs HEMTs and HBTs. He is currently a Professor in the Department of Electrical and Computer Engineering and the Associate Dean of the School of Engineering, University of California at Santa Barbara (UCSB). He has authored or coauthored over 450 papers in technical journals and conferences. He holds nine patents. His current research interests are in oxide-based IIIV electronics and IIIV nitride electronics and opto-electronics. Dr. Mishra was a recipient of the Presidential Young Investigator Award from the National Science Foundation, the Hyland Patent Award presented by Hughes Aircraft, the Young Scientist Award presented at the International Symposium on GaAs and Related Compounds and the 2007 David Sarnoff Award from the IEEE. He was elected to the US National Academy in 2009.

The dominance of Silicon (Si) has been due to three major factors:
1. The existence of the miraculous dielectric; Silicon Dioxide (SiO2) which has exhibits low bulk charge density and ultra-low interface and bulk traps allowing both electron and hole inversion layers enabling CMOS
2. A near-ideal band gap (1.1eV) which allows wide-spread use at room temperature and the ability to contact both the conduction and valence bands with a variety of metals
3. The large number of applications has enabled vast economies of scale which has made the Si technology vastly affordable.

The one major drawback of Si is that it has an indirect band gap and hence cannot emit light efficiently. Also, its band gap, though perfect for many applications, is still limited for several applications that require the switching of high voltages and currents at a high speed. This second requirement is represented by markets such as microwave power transmitters and power conversion for efficient power supplies, photo-voltaic applications, and motor drives. This problem of light emission and of microwave amplifiers (in part) has been filled traditionally by compound semiconductors such GaAs and InP based semiconductors. However, even these semiconductors had limits most especially not being able to deliver the blue, green and white emitters, so essential in display applications. This blue-green-white void was filled by the emergence of the Gallium Nitride-based material (including Indium Gallium Nitride; InGaN). This has enabled the emergence of high-efficiency Solid State Lighting. The potential application of GaN has expanded to the microwave application and even to power conversion markets where the critical advantage that it brings to the problem is again that of higher efficiency. This expansion of markets allows the potential of large economies of scale which can make for the first time a compound semiconductor affordable like Si is today.

GaN based emitters are now available in LED TVs, traffic signs (green and white), Blu-Ray DVD players (using blue lasers), microwave power amplifiers for WiMax applications . It is now being actively researched for power conversion which opens large new markets which will establish its place as the next dominant semiconductor after Silicon.

Towards High-Performance and Reconfigurable Optical Communication Networks

When : Tuesday, September 15, 2009 - 02:00
Speaker : Prof. Alan E. Willner
Affiliation : University of Southern California
Where : Aula Magna A. Lepschy

Abstract :

Short bio: Alan Willner (Ph.D., Columbia) has worked at AT&T Bell Labs and Bellcore, and is Prof. of EE at USC. He received the NSF Presidential Faculty Fellows Award from the White House, Packard Foundation Fellowship, Fulbright Senior Scholars Award, and Eddy Paper Award. Prof. Willner was IEEE LEOS President, General Co-Chair of CLEO, and Editor-in-Chief of IEEE/OSA J. Lightwave Technology and OSA Optics Letters. He has 750 publications.

Abstract: Optical communications has enjoyed dramatic growth in terms of technical achievement as well as commercial implementation. This presentation will highlight three main topics.  Firstly, a broad perspective will be given on some of the technical trends in optical communication systems.  Secondly, I will describe technical issues related to stable, robust optical networking, including performance monitoring, channel-degrading effects, efficient modulation formats, and switching. Finally, I will discuss adding flexibility and reconfigurability to different aspects of the base optical technologies.

Robustness in Biological Networks: From Genes to Cells to Systems

When : Thursday, May 7, 2009 - 17:00
Speaker : Prof. Francis J. Doyle III
Affiliation : University of California, Santa Barbara
Where : Aula Magna A. Lepschy

Abstract :

Short bio: Dr. Francis J. Doyle III holds the Duncan and Suzanne Mellichamp Chair in Process Control in the Department of Chemical Engineering at UCSB. He received his B.S.E. from Princeton, C.P.G.S. from Cambridge, and Ph.D. from Caltech. He is the recipient of numerous awards including the Computing in Chemical Engineering Award from the AIChE and has been named a Fellow of the IEEE.

Abstract: A property of particular interest in systems biology is the robustness of a biophysical network: the ability to maintain some target level of behavior or performance in the presence of uncertainty and/or perturbations. In biological systems, these disturbances can be environmental (heat, pH, etc.) or intrinsic to the organism (changes in kinetic parameters arising from molecular fluctuations). While preliminary results are available for simple (low-dimensional, deterministic) biological systems, general tools for analyzing these tradeoffs are the subject of active research. Tools from systems theory are introduced that elucidate design principles in these complex architectures through the analysis of robust and fragile regions of the network. Analysis of the performance properties of circadian gene networks in Arabidopsis, Drosophila, and Mouse reveals the design principles that emerge from these richly layered and hierarchical regulatory circuits. We highlight some recent results that analyze robustness properties at the tissue level, where intercellular coupling appears to be responsible for the generation of robust rhythms in the face of noise and other uncertainties. In the absence of intercellular signaling, the individual (cellular) oscillators lose these properties of robust performance. Finally, we will show that these insights (robustness and performance analysis) can be applied to the design of 'forcing' or control protocols that allow for rapid re-entrainment of the clock.

Presentation: PDF

Polyhedral Approaches to Integer Programming

When : Thursday, April 2, 2009 - 17:00
Speaker : Prof. Gerard Cornuejols
Affiliation : Carnegie Mellon University
Where : Aula Magna A. Lepschy

Abstract :

Short bio: Gerard Cornuejols is a professor at Carnegie Mellon University in Pittsburgh and the University of Marseille. His main scientific interests involve operations research, integer programming, logistics and optimization methods in finance, altough contributions were given also in location and distribution, graph theory, packing and covering problems. He was awarded some of the most prestigious prizes in the operations research community: the Fulkerson Prize (2000) offered jointly by the American Math Society and the Math Programming Society, and the SIAM Outstanding Paper Prize (2004). He was editor-in-chief of Mathematics of Operations Research from 1998 to 2003.

Abstract: This survey introduces integer programming and tools from polyhedral theory that are used in integer programming. It applies these tools to the study of cutting planes, such as Gomory cuts.

The analysis and design of the steady-state behavior of nonlinear systems: Taming nonlinear excursions in the spirit of Lagrangia and Liapunov

When : Wednesday, February 4, 2009 - 16:30
Speaker : Prof. Christopher I. Byrnes
Affiliation : Edward H. and Florence G. Skinner Professor of Systems Science and Mathematics, Washington University in St. Louis
Where : Aula Magna A. Lepschy

Abstract :

Short bio: The author of more than 250 technical papers and books, Chris Byrnes received an Honorary Doctorate of Technology from the Royal Institute of Technology (KTH) in Stockholm in 1998 and in 2002 was named a Foreign Member of the Royal Swedish Academy of Engineering Sciences. He is a Fellow of the IEEE and in 2005 was awarded the Reid Prize from SIAM for his contributions to Control Theory and Differential Equations. He will hold the Giovanni Prodi Chair in Nonlinear Analysis at the University of Wuerzburg in the summer of 2009 and spend the 2009-2010 academic year as Gast Professor at KTH, supported by the Swedish Strategic Research Foundation.

Abstract:A long term goal in the theory of systems and control is to develop a systematic
methodology for the design of feedback control schemes capable of shaping the re-
sponse of complex dynamical systems, in both an equilibrium and a nonequilibrium
setting. In this talk, we will focus primarily on periodic steady-state behavior, a phe-
nomenon that is pervasive in nature and in man-made systems. We will begin with an
analysis of Brockett's recent design of a feedback law which creates an asymptotically
stable oscillation in a three dimensional, nonholonomic model of an AC controlled
rotor with a constant steady-state angular velocity. We will show how to design
feedback laws for stabilizable n-dimensional systems so that the existence, periods
and stability of periodic responses can be analyzed and shaped when the nonlinear
feedback system is driven with an arbitrary periodic input.

This design is the result of joint work with joint work with R. Brockett and with A.
Isidori. The sufficient conditions use a multi-valued analogue of Liapunov functions,
in much the same way as the angular variable θ in polar coordinates is multi-valued.
For the AC motor the angular variable is the rotational component of the magnetic
field while for the two body problem with a central force field the existence of an
angular variable is a consequence of conservation of angular momentum. In the
general case, the sufficient conditions can be checked point-wise, just as in Liapunov
theory, without knowledge of the trajectories of the system or a cross-section for
the dynamics. Moreover, these techniques can be used to shape the Lagrange stable
orbits of dissipative nonlinear feedback systems, a key to solving problems of output
regulation. Finally, using the recent solution of the Poincar ́ Conjecture and more, we e show these sufficient conditions are necessary for the existence of an asymptotically
stable oscillation - similar in spirit of the converse theorems of Liapunov theory.