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SUNMONTUEWEDTHUFRISAT
Conferences, Lectures, & Seminars
Events for May
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Can the Earth Produce the Biomass We Demand
Thu, May 01, 2008 @ 12:45 PM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Lyman Handy Colloquium presentsProfessor Tadeusz W. PatzekDepartment of Civil and Environmental Engineering
University of California - BerkeleyAbstractTo demonstrate the utter impossibility of sustained, industrial-scale production of biofuels anywhere and from and source, I consider the local,
field-scale sustainability of a productive industrial maize agrosystem that has replaced a fertile grassland ecosystem. Using the revised Second Law approach of Svirezhev, I show that currently this agrosystem is unsustainable in the US (and anywhere else), with or without tilling the
soil. The calculated average erosion rates of soil necessary to dissipate the entropy produced by US maize agriculture, 23 -- 45 t/ha-yr, are bounded
from above by an experimental estimate of mean soil erosion by conventional agriculture worldwide, 47 t/ha-yr. Between 1982 and 1997, US agriculture
caused an estimated 7 -- 23 t/ha-yr of average erosion with the mean of 15 t/ha-yr. The lower mean erosion rate of no till agriculture, 1.5 t/ha-yr,
necessitates the elimination of weeds and pests with field chemicals -- with the ensuing chemical and biological soil degradation, and chemical runoff -- to dissipate the produced entropy. The increased use of field chemicals that replace tillers is equivalent to the killing or injuring of up to 300 kg/ha-yr of soil flora and fauna. Additional soil degradation, not discussed
here, occurs by acidification, buildup of insoluble metal compounds, and buildup of toxic residues from field chemicals. The degree of unsustainability of an average US maize field is high, requiring 6 -- 13 times more energy to remediate soil degradation, etc., than the direct energy inputs to maize agriculture. This additional energy, if spent, would
not increase maize yields. The calculated ``critical yield'' of ``organic'' maize agriculture that does not use field chemicals and fossil fuels is only 30 percent lower than the average maize yield of 8.7 tons per hectare (140 bushel/acre) assumed here. Immediate attention should be devoted in the US to more sustainable alternatives to the current industrial agriculture. I will also discuss the implications of my findings to the current wholesale destruction of the tropical ecosystems. URL: http://petroleum.berkeley
Location: Olin Hall of Engineering (OHE) - 122
Audiences: Everyone Is Invited
Contact: Petra Pearce Sapir
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System Earthquake Risk Assessment (SERA)
Thu, May 01, 2008 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Dr. Dennis Ostrom, Consultant - San Diego Gas & Electric, Pacific Gas & Electric, and Southern California EdisonDr. Ostrom will present the Development of a utility developed System Earthquake Risk Assessment (SERA) and present it from a utility perspective. Characterization of the hazard, component vulnerability, system vulnerability, development of performance goals, return to service times, system performance and future studies and/or research will be discussed and presented.
Location: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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CS Colloq: AND/OR Search Strategies for Combinatorial Optimization in Graphical Models
Thu, May 01, 2008 @ 03:30 PM - 04:30 PM
Thomas Lord Department of Computer Science
Conferences, Lectures, & Seminars
Title: AND/OR Search Strategies for Combinatorial Optimization in Graphical ModelsSpeaker: Radu Marinescu (UCI)Abstract:
The AND/OR search space for graphical models is a new framework for search that is sensitive to the independencies in the model, often resulting in exponentially reduced complexities. The AND/OR search tree search is in most cases exponentially smaller (and never larger) than the OR search tree. The AND/OR search graph is exponential in the treewidth of the graph, while the OR search graph is exponential in the pathwidth. We introduce a new generation of depth-first Branch-and-Bound as well as best-first AND/OR search algorithms that explore the context minimal AND/OR graph for solving general constraint optimization problems over graphical models. In conjunction with the AND/OR search space we also investigate a class of partitioning-based heuristic functions, based on the Mini-Bucket approximation that was shown to be powerful for optimization problems in the context of OR search spaces. Since variable selection can have a dramatic impact on search performance, we also introduce a class of depth-first AND/OR Branch-and-Bound and best-first AND/OR search algorithms that can accommodate various dynamic variable ordering heuristics. An extensive empirical evaluation showed conclusively that the new AND/OR search approach improves considerably over the traditional OR search, on a variety of probabilistic and deterministic benchmarks. We next apply the AND/OR perspective to decision diagrams. We extend them with AND nodes capturing function structure decomposition, resulting in AND/OR Multi-Valued Decision Diagrams (AOMDDs). The AOMDD is a canonical form that compiles a graphical model and has size bounded exponentially by the treewidth, rather than pathwidth (as is the case for OR decision diagrams). We present an AND/OR search based algorithm for compiling AOMDDs, as representations of the optimal set of solutions of a constraint optimization problem. An extensive experimental evaluation proved the efficiency of the weighted AOMDD data structure.Location: Seaver Science Library (SSL) - 150
Audiences: Everyone Is Invited
Contact: CS Colloquia
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CFD-approach in investigation of consequences of accidental large-scale fires
Wed, May 07, 2008 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Dr. Medzid Muhasilovic - EPFL Swiss Federal Institute of Technology AbstractDue to the increasing accidental fires in enclosures, especially in that area of modern society where our freedom is mostly expressed – traffic and tourism – there is an on-growing need to undertake scientific and technological research, aiming at better understanding of these reactive flow phenomena and their consequences. One of the direct benefits coming out of such research is implication of optimal methods for fire suppression that certainly must get along with world-wide statistical data for one tunnel-fire on each 107th kilometre of covered (tunnel) road.
Results of the CFD-investigation on simulated heptane-fires of Heat Release Rate (HRR) of 20MW and of 50MW within two different road tunnels without forced longitudinal ventilation, are presented, pointing at both at the direct and indirect consequences of such large-scale uncontrolled combustion.Keywords: Fires in Enclosures, HRR, Tunnel, Soot Distribution, IrradianceLocation: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Optimum Cleanup Scenarios for VOCs and Perchlorate in Baldwin Park Operable Unit, San Gabriel Valle
Wed, May 07, 2008 @ 04:00 PM - 06:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
PhD Defense for Christian SamThe Baldwin Park Operable Unit (BPOU) in the San Gabriel Valley basin, California has been identified by the USEPA as a ground water contaminant superfund site. This research employs optimized hydraulic gradient control to cost-effectively remove the contaminant plumes. Perchlorate (PCR) and Volatile Organic Compounds (VOCs), predominantly tetrachloroethene (PCE) and trichloroethene (TCE) are still prevalent in the Baldwin Park Operable Unit (BPOU). This study proposes a methodology that optimizes available ground water and surface water resources and blocks, traps and reduces the contaminant concentration below the maximum contaminant level (MCL) or notification level (NL). The current strategy by USEPA and other agencies involved in the cleanup of BPOU is "pump and treat." Pump and treat has not been effective as high levels of PCE, TCE and PCR are still prevalent in BPOU after approximately 14 years of clean up. Blending ground water from wells not impacted by the contamination with ground water from wells impacted by the contamination is a supplemental strategy employed by the water purveyors to circumvent the contamination problem. This research provides an overall systematic strategy to clean up the entire aquifer at BPOU.The MODFLOW, MODPATH and RT3D modules of Ground Water Vistas (ground water modeling program) are used to generate the ground water flow model, particle tracking model and contaminant transport models. Further migration of the contaminants is limited. Contaminants are rapidly trapped and removed by a set of experimentally designed injection and production wells. The procedure utilizes sequential simulation with optimization to optimally and rapidly remove the contaminants using a hydraulic gradient scheme. The hydraulic gradient scheme was run to test future scenarios using assumed wet and dry cycles from the hydrologic base period.An economic analysis was performed to compare the cost of the existing system with the cost of the strategy proposed in this study. The strategy proposed in this study resulted in a cost effective solution.
Location: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Carbon Foams and Carbon Nanotubes: Modeling Based on Structural Mechanics
Thu, May 08, 2008 @ 02:00 PM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
Dr. Xin-Lin Gao, Professor Texas A&M UniversityAbstractCarbon foams, first developed at the Air Force Research Laboratory (AFRL) in the 1990s, are rapidly emerging as a new class of ultra-light cellular materials for structural and thermal management applications. They are blown from a coal-based or chemically synthesized pitch precursor through a bubble forming process and have a 3-D open-cell structure, with the cell size ranging from tens to hundreds of microns. Recent research efforts have been focused on how to optimize the foam properties based on reliable processing-structure-property relationships. In the first part of this seminar, three micromechanical and computational models developed by the speaker's group using structural mechanics will be discussed. The first two are based on a single unit cell (a tetrakaidecahedron), with one using Castigliano's second theorem and the other employing the matrix method for space frames. The third model accounts for the randomness in foam microstructures and involves hundreds of cells, which is developed using the Voronoi tessellation technique and the finite element method.The discovery of carbon nanotubes in 1991 is one of the key breakthroughs that have taken us into an emerging era of nanotechnology. Nanostructured materials will be playing a critical role in the new era. In the second part of this seminar, two multi-scale analytical and computational models developed by the speaker's group using structural mechanics and energy principles will be presented. One is a shear-lag model for estimating load transfer in carbon nanotube-reinforced polymer matrix composites based on molecular structural mechanics and elasticity, and the other is a continuum-based model for predicting Young's modulus of single-walled carbon nanotubes developed using finite deformation kinematics and energy equivalence.
Location: Kaprielian Hall (KAP) - 209
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
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Topics in Networking Research *
Mon, May 12, 2008 @ 02:00 PM - 03:30 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
SPEAKER: Dr. Debasis Mitra
Bell Labs, Alcatel-Lucent,
Murray Hill, NJ 07974, USAABSTRACT: What are the big movements in networking that researchers should heed? A standout is the global spread of communities of interest (the networking analogue of the flat world) and their need for "dynamic virtual networks" that support rich applications requiring resources from several domains. There is a definite imperative for inter-networking, i.e., resource sharing across multiple domains. This challenge has many facets, ranging from the organizational, e.g., different, possibly competing, owners to the technical, e.g., different technologies. Yet another key characteristic of the emerging networking environment is that the service provider is required to handle ever-increasing uncertainty in demand, both in volume and time. Thus, inter-networking and uncertainty management are important challenges of emerging networking that deserve attention from the research community. We describe research that touch on both topics. In the first part, we consider a model of data-optical inter-networking. In the second part, we present a framework for stochastic traffic management in which traffic demands are uncertain. We consider various measures of risk in networking and, having selected one, we obtain results on the optimization of an objective which is a risk-adjusted measure of network revenue. *Joint work with Qiong Wang and Anwar Walid, Bell Labs, Murray HillBIOGRAPHY: Debasis Mitra is Vice President in the Chief Scientist's Office of Bell Labs, Alcatel-Lucent. He is responsible for global research partnerships and academic relations. From 1999-2007 as Vice President of the Mathematical and Algorithmic Sciences Research Center he directed activities in fundamental mathematics, algorithms, complex systems analysis and optimization, statistics, learning theory, information and communications sciences, and industrial mathematics.Dr. Mitra is a member of the National Academy of Engineering, a Bell Labs Fellow and a Fellow of the IEEE. He is a recipient of the 1998 IEEE Eric E. Sumner Award, the 1993 Steven O. Rice Prize Paper Award and the 1982 Guillemin-Cauer Prize Paper Award of the IEEE. He is also the recipient of awards from the 1995 ACM Sigmetrics/Performance Conference, the Institution of Electrical Engineers (UK) and the Bell System Technical Journal. He has been a member of the editorial boards of the IEEE/ACM Transactions on Networking, the IEEE Transactions of Communications, the IEEE Transactions on Circuits and Systems and Queueing Systems (QUESTA). During 2002-2005 he served as the area editor responsible for Telecommunications and Networking for the journal Operations Research. He holds more than 15 patents. In 2003 he served as the Chair of the Telecom review panel of the N.J. Commission on Jobs Growth and Economic Development. He has been McKay Professor at the University of California, Berkeley, and the Albert Winsemius Professor at the Nanyang Technical University in Singapore and in 2005 he was a visiting professor at the Indian Institute of Science, Bangalore. During 2006 he chaired the Mathematics Advisory Committee of the Science Foundation of Ireland. He serves on the Air Force Studies Board of the National Academies.HOST: Professor Urbashi Mitra, ubli@usc.eduLocation: Hughes Aircraft Electrical Engineering Center (EEB) - 248
Audiences: Everyone Is Invited
Contact: Gerrielyn Ramos
