Select a calendar:
Filter April Events by Event Type:
SUNMONTUEWEDTHUFRISAT
Events for April 27, 2010
-
Spectroscopic insights to the Fe(II)-Fe(III) redox system at mineral surfaces:
Tue, Apr 27, 2010 @ 02:00 AM - 03:00 PM
Sonny Astani Department of Civil and Environmental Engineering
Conferences, Lectures, & Seminars
... Implications for iron mineral formation and contaminant reduction.Speaker: Dr. Philip Larese-Casanova, Geology and Geophysics Department, Yale UniversityAbstract: The attenuation of groundwater contaminants has been closely linked with the chemical reactivity of native iron minerals. Dissolved Fe(II) can provide electrons that reduce contaminants to less toxic products, and this electron transfer process is catalyzed by reactive surface sites on Fe(III) minerals. However, the Fe(II)-Fe(III) redox reactions occurring at mineral surfaces are not fully understood because it is difficult to target and directly observe the physical and chemical activity of surficial iron atoms. Over the past few years, our observations of iron surfaces have become more sensitive by using 57Fe-Mössbauer spectroscopy with selective use of 57Fe and 56Fe isotopes. The process of dissolved 57Fe(II) sorption onto 56Fe(III) oxide surface sites (56hematite) was revealed instead to be a combined process of 57Fe(II) sorption and electron transfer to the bulk oxide, forming a new 57Fe(III) surface layer. 56Hematite has a capacity for this 57Fe(III) layer growth beyond which stable sorbed 57Fe(II) atoms reside on its surface. The transferred electrons within hematite rapidly hop among Fe atoms, a process others predicted to occur using computational methods. These spectroscopic observations are the first of their kind and highlight the need for new metal sorption models to account for redox-active sorbents. Contaminant reduction by dissolved 57Fe(II) and 56Fe(III) oxides results in further 57Fe(III) surface layer growth and the formation of new surface iron minerals, such as nano-sized 57goethite on 56hematite or 57lepidocrocite on 56magnetite, and these surface precipitates can alter the rate of contaminant reduction. Fe surface precipitates can also form via microbial Fe(II)-oxidation, and we have quantified iron phases formed (57lepidocrocite and 57goethite) during microbial oxidation of 57Fe(II) by the Fe(II)-oxidizing bacterium Acidovorax sp. BoFeN1 and have examined their dependence on geochemical solution conditions. Overall, contaminant reduction by the Fe(II)-Fe(III) redox couple is highly dependant on the supporting mineral substrate, and subtle changes to mineral surfaces or geochemical conditions can have profound effects on contaminant reduction rates or Fe(III) mineralogy.
Location: Kaprielian Hall (KAP) - 209 )
Audiences: Everyone Is Invited
Contact: Evangeline Reyes
-
Tech Video Job Fair
Tue, Apr 27, 2010 @ 08:00 AM - 05:00 PM
Viterbi School of Engineering Alumni
Receptions & Special Events
Chat with top Silicon Valley Companies using your webcam!Yahoo, Flixter, and Tagged are just some of the companies hiring and are conduction interviews online. Interviews conducted April 26-30th. For more information and to register visit http://www.jobnob.com/job-fair/SiliconValleyVideoFair?utm_source=USC&utm_medium=email&utm_campaign=USC
Audiences: Everyone Is Invited
Contact: Kathleen Concialdi
-
Secure Collision-Free Frequency Hopping for STC-OFDM Based Wireless Networks
Tue, Apr 27, 2010 @ 11:00 AM - 12:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Leonard E. Lightfoot,
Michigan State University,
Department of Electrical & Computer EngineeringAbstract: With the majority of today's transactions and communications relying heavily on wireless networks, the security threats of malicious jamming, detection, and interception are no longer limited to military applications. In fact, security is the key enabler for present and future high speed wireless networks. Patching or add-on security maybe effective in short term, but is far from adequate for addressing the needs on wireless security and can greatly complicate the communication systems. In our research, we focus on the fundamental study of developing a spectrally efficient and inherently secure wireless system by exploiting multiple diversity techniques.We propose an innovative spectrally efficient, jamming-resilient wireless scheme by exploiting the joint space-time and frequency diversity. Existing anti-jamming systems such as frequency hopping (FH) rely heavily on rich time-frequency diversity over large spread spectrums. Mainly limited by multiuser interference, the spectral efficiency of existing jamming resistant systems are very low due to inefficient use of the large bandwidth. While these systems work reasonably well for voice centric communications which only requires relatively narrow bandwidth, their low spectral efficiency can no longer provide sufficient capacity for today's high speed multimedia wireless services. In this research, (i) we develop a collision-free frequency hopping (CFFH) system based on the orthogonal frequency division multiplexing (OFDM) framework and the secure subcarrier assignment algorithm. The proposed subcarrier assignment algorithm is designed to ensure that malicious users cannot predict or repeat the hopping pattern of the authorized users and hence cannot launch follower jamming attacks; (ii) We improve the performance of the CFFH system under random jamming, by enhancing the system diversity through space-time coding, and introduce the space-time coded collision-free frequency hopping (STC-CFFH) system. Our analysis indicates that the proposed scheme is both highly efficient and very robust under various jamming scenarios. The proposed approach breaks new ground in the design and development of secure high speed wireless communication systems. Biography: Dr. Leonard Lightfoot received his B.S degree in Computer Engineering from Xavier University of Louisiana, New Orleans, LA in May 2004. Upon completing his B.S. degree in 2004, he began his graduate studies at Michigan State University, East Lansing, MI, where he received his M.S and Ph.D. degrees in Electrical Engineering in December 2006 and March 2010, respectively. In July 2010, Leonard will join the research team in the Sensors Directorate at the Air Force Research Laboratory located in Dayton, Ohio. Leonard's current research interest includes developing and designing highly efficient and reliable wireless communications, and network security.Host: Michael Neely, neely@usc.edu, EEB 520, 213-740-3505
Location: Hughes Aircraft Electrical Engineering Center (EEB) - 248
Audiences: Everyone Is Invited
Contact: Gerrielyn Ramos
-
Performance of Tall Buildings during the 2/27/2010 Chile M8.8 Earthquake
Tue, Apr 27, 2010 @ 03:00 PM - 05:00 PM
USC Viterbi School of Engineering
Conferences, Lectures, & Seminars
The Los Angeles Tall Buildings Structural Design Council presents a city-by-city discussion of the recent supertemblorINTRODUCTION
Farzad Naeim, John A. Martin & AssociatesSEISMICITY AND GEOTECTONICS
Marshall Lew, MACTEC EngineeringSTANDARD OF PRACTICE FOR TALL BUILDINGS IN CHILE
Fabian Rojas, USCPERFORMANCE OF TALL BUILDINGS IN SANTIAGO
Farzad Naeim, John A. Martin & AssociatesPERFORMANCE OF TALL BUILDINGS IN VIÑA DEL MAR
Lauren Carpenter, WHL InternationalPERFORMANCE OF TALL BUILDINGS IN CONCEPCIÓN
Fabian Rojas, USCPERFORMANCE OF TALL BUILDINGS IN SAN PEDRO
Nabih Youssef, NYACONCLUSIONS AND QUESTIONS/ANSWERS
Farzad Naeim (moderator)Co-sponsored by:
USC Sonny Astani Department of Civil and Environmental Engineering
EERI Southern California Chapter
USC EERI/SCEC Student Chapter
Structural Engineers Association of Southern California
Location: Troyland Apartments (TAP) - er Hall Room 101
Audiences: Everyone Is Invited
Contact: Eric Mankin
-
CS Colloq: Amarjeet Singh
Tue, Apr 27, 2010 @ 03:30 PM - 05:00 PM
Thomas Lord Department of Computer Science
Conferences, Lectures, & Seminars
Talk Title: Application driven research in sensing and mobile computingSpeaker: Prof. Amarjeet SinghHost: Prof. Gaurav SukhatmeAbstract: Recent advancements in sensing technologies and mobile proliferation have significantly impacted several applied domains including environmental sensing and rural technology respectively. In sensing domain, applications that exhibit complex dynamics across both space and time and that can only be partially observed are of particular interest. In rural technology, primary focus is on applications that are user friendly even for an illiterate person. For both environmental sensing and rural technology, there exists a problem of constrained resources. Further, lack of prior use of advanced technology in both the domains necessitates that for high fidelity understanding of such environments an iterative approach wherein real world deployment experiences in application domain should guide both the advancements in systems as well as deployment methodology.In this talk, I will first present our real world deployment experiences (using Networked Info Mechanical System – NIMS, developed at UCLA) in several critical environmental sensing applications including monitoring pollution in rivers and algae growth in lakes.
Large spatial expanse of such applications, together with limited available resources (sensing time or battery capacity) for mobile agents motivated our further research in performing efficient path planning for these mobile agents. I will present novel approximation algorithms for solving this NP-hard problem of path planning for mobile agents in such complex environments. In particular, we used Gaussian Process modeling to accurately represent the dynamics we observed in our real world deployments. We exploit several machine learning concepts to provide strong theoretical guarantees for the proposed algorithms. Several field experiments were performed, in addition to using multiple real world sensing datasets, to validate the effectiveness of the proposed algorithms for real world sensing applications.I will then move from mobile sensing for environmental applications to application driven research using mobile computing for addressing several challenges in socially responsive applications, particularly in the context of developing countries. I will first present the contextual difference between challenges in developing and developed countries for applications in mobile computing. Motivated by India specific contexts, I will then present some early stage work in two specific application areas of mobile computing – healthcare and GPS-less localization.Bio:Amarjeet Singh is currently an Asst. Professor in Mobile and Ubiquitous Computing group at Indraprastha Institute of Information Technology, Delhi. He completed his MS and Phd in Electrical Engineering from UCLA in 2007 and 2009 respectively. He was awarded
2009 Chorafas Foundation Award for applied research with long range implications. He was also a recipient of 2007 Edward K. Rice outstanding MS student in School of Engineering at UCLA. From 2002 – 2004, he worked as Senior Research and Development Engineer at Tejas Networks, Bangalore, India. His undergraduate education was in Electrical Engineering from Indian Institute of Technology, Delhi in 2002.
Location: Seaver Science Library (SSL) - 150
Audiences: Everyone Is Invited
Contact: CS Front Desk
