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Articles 4591 - 4620 of 6327

Full-Text Articles in Engineering

Compositional Contrast Of Biological Materials In Liquids Using The Momentary Excitation Of Higher Eigenmodes In Dynamic Atomic Force Microscopy, Xin Xu, John Melcher, Sudipta Basak, R. Reifenberger, Arvind Raman Feb 2009

Compositional Contrast Of Biological Materials In Liquids Using The Momentary Excitation Of Higher Eigenmodes In Dynamic Atomic Force Microscopy, Xin Xu, John Melcher, Sudipta Basak, R. Reifenberger, Arvind Raman

Birck and NCN Publications

Atomic Force microscope (AFM) cantilevers commonly used for imaging soft biological samples in liquids experience a momentary excitation of the higher eigenmodes at each tap. This transient response is very sensitive to the local sample elasticity under gentle imaging conditions because the higher eigenmode time period is comparable to the tip-sample contact time. By mapping the momentary excitation response, we demonstrate a new scanning probe spectroscopy capable of resolving with high sensitivity the variations in the elasticity of soft biological materials in liquids.

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Materializing A Binary Hyperlens Design, Alexander V. Kildishev, Uday K. Chettiar, Zubin Jacob, V. M. Shalaev, Evgenii Narimanov Feb 2009

Materializing A Binary Hyperlens Design, Alexander V. Kildishev, Uday K. Chettiar, Zubin Jacob, V. M. Shalaev, Evgenii Narimanov

Birck and NCN Publications

We present a design of cylindrical hyperlens made of a layered binary material. The design approach uses an improved effective medium theory to take account of radius-dependent effects due to curvature of material interfaces resulting in nonperiodically distributed thicknesses of the lens layers. The performance of this lens is compared versus the designs with periodically thick layers, which we showed in earlier papers. Detailed quantitative results analyzed for the lenses with the same number and starting order of layers prove better functioning of the lens designed with this approach.

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Imaging Gold Nanorods By Plasmon-Resonance-Enhanced Four Wave Mixing, Yookyung Jung, Hongtao Chen, Ling Tong, Ji-Xin Cheng Feb 2009

Imaging Gold Nanorods By Plasmon-Resonance-Enhanced Four Wave Mixing, Yookyung Jung, Hongtao Chen, Ling Tong, Ji-Xin Cheng

Other Nanotechnology Publications

The current work investigates the four-wave mixing (FWM) signal from gold nanorods (NRs) using two synchronized lasers and its potential applications in bioimaging. Using the lightning rod model, we show that the strongest FWM occurs when the pump laser wavelength is tuned to be resonant with the longitudinal plasmon resonance wavelength of NR. The calculation is experimentally demonstrated by comparing the intensities of FWM from NRs with different plasmon resonance wavelengths. The FWM signal is further found to be enhanced by aggregation of NRs and is strongly dependent on pulse width. The FWM intensity from NRs is similar to 39 …

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Influence Of Dimensionality On Thermoelectric Device Performance, Raseong Kim, Supriyo Datta, Mark S. Lundstrom Feb 2009

Influence Of Dimensionality On Thermoelectric Device Performance, Raseong Kim, Supriyo Datta, Mark S. Lundstrom

Birck and NCN Publications

The role of dimensionality on the electronic performance of thermoelectric devices is clarified using the Landauer formalism, which shows that the thermoelectric coefficients are related to the transmission, T(E), and how the conducting channels, M(E), are distributed in energy. The Landauer formalism applies from the ballistic to diffusive limits and provides a clear way to compare performance in different dimensions. It also provides a physical interpretation of the "transport distribution," a quantity that arises in the Boltzmann transport equation approach. Quantitative comparison of thermoelectric coefficients in one, two, and three dimensions shows that the channels are utilized more effectively in …

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Support Vector Selection And Adaptation For Classification Of Remote Sensing Images, Gulsen Taskin Kaya, Okan Ersoy Feb 2009

Support Vector Selection And Adaptation For Classification Of Remote Sensing Images, Gulsen Taskin Kaya, Okan Ersoy

Department of Electrical and Computer Engineering Technical Reports

Classification of nonlinearly separable data by nonlinear support vector machines is often a difficult task especially due to the necessity of a choosing a convenient kernel type. In this study, we propose a new classification method called support vector selection and adaptation (SVSA) that is applicable to both linearly and nonlinearly separable data in terms of some reference vectors generated by processing of support vectors obtained from the linear SVM. The method consists of two steps called selection and adaptation. In these two steps, once the support vectors are obtained by a linear SVM, some of them are rejected and …

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Valley Degeneracies In (111) Silicon Quantum Wells, Neerav Kharche, Seongmin Kim, Timothy B. Boykin, Gerhard Klimeck Jan 2009

Valley Degeneracies In (111) Silicon Quantum Wells, Neerav Kharche, Seongmin Kim, Timothy B. Boykin, Gerhard Klimeck

Birck and NCN Publications

(111) silicon quantum wells have been studied extensively, yet no convincing explanation exists for the experimentally observed breaking of sixfold valley degeneracy into two- and fourfold degeneracies. Here, systematic sp(3)d(5)s(*) tight-binding and effective mass calculations are presented to show that a typical miscut modulates the energy levels, which leads to breaking of sixfold valley degeneracy into two lower and four raised valleys. An effective mass based valley-projection model is used to determine the directions of valley minima in tight-binding calculations of large supercells. Tight-binding calculations are in better agreement with experiments compared to effective mass calculations.

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Spin-Orbit Splittings In Si/Sige Quantum Wells: From Ideal Si Membranes To Realistic Hterostructures, M. Prada, G. Klimeck, R. Joynt Jan 2009

Spin-Orbit Splittings In Si/Sige Quantum Wells: From Ideal Si Membranes To Realistic Hterostructures, M. Prada, G. Klimeck, R. Joynt

Birck and NCN Publications

We present a calculation of the wavevector-dependent subband level splitting from spin-orbit coupling in Si/SiGe quantum wells. We first use the effective-mass approach, where the splittings are parameterized by separating contributions from the Rashba and Dresselhaus terms. We then determine the inversion asymmetry parameters by fitting tight-binding numerical results obtained using the quantitative nanoelectronic modeling tool, NEMO-3D. We describe the relevant coefficients as a function of applied electric field and well width in our numerical simulations. Symmetry arguments can also predict the behavior, and an extensive analysis is also presented in this work. Using vast computational resources, we treat alloy …

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Nano-Switch For Study Of Gold Contact Behavior, Adam Fruehling, Shijun Xiao, Minghao Qi, Kaushik Roy, Dimitrios Peroulis Jan 2009

Nano-Switch For Study Of Gold Contact Behavior, Adam Fruehling, Shijun Xiao, Minghao Qi, Kaushik Roy, Dimitrios Peroulis

Birck and NCN Publications

In this paper we present the fabrication and characterization of a new NEMS DC switch as a vehicle to characterize Au-to-Au contacts at nano-scale. The switch consists of a 1050-nm long, 200-nm wide and 50-nm thick cantilever gold beam. The measured on-state resistance values range from 83 Omega to 640 Omega and the actuation voltages from 4 V to 22 V. All measurements are conducted at a current of 1 mu A and the obtained values are in good qualitative agreement with traditional elastic-plastic contact models. The calculated switching time is 55 ns. Characterization of contacts at nano-scale will be …

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Foreword For The Special Issue Of Selected Papers From The 1st Acm Sigspatial Workshop On Security And Privacy In Gis And Lbs, Elisa Bertino, Maria Luisa Damiani Jan 2009

Foreword For The Special Issue Of Selected Papers From The 1st Acm Sigspatial Workshop On Security And Privacy In Gis And Lbs, Elisa Bertino, Maria Luisa Damiani

Cyber Center Publications

The first Workshop on Security and Privacy in GIS and LBS (SPRINGL 2008) was organized on November 4, 2008 at Irvine (CA) in conjunction with the SIGSPATIAL International Conference on Advances in Geographic Information Systems (ACM GIS 2008). The goal of the SPRINGL workshop series is to provide a forum for researchers working in the area of geospatial data security and privacy. Both security and privacy are critical for geospatial applications because of the dramatic increase and dissemination of geospatial data in several application contexts including homeland security, environmental crises, and natural and industrial disasters. Furthermore, geospatial infrastructures are being …

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Stabilizing Nanostructured Materials By Coherent Nanotwins And Their Grain Boundary Triple Junction Drag, C Saldana, T G. Murthy, M R. Shankar, E A. Stach, S Chandrasekar Jan 2009

Stabilizing Nanostructured Materials By Coherent Nanotwins And Their Grain Boundary Triple Junction Drag, C Saldana, T G. Murthy, M R. Shankar, E A. Stach, S Chandrasekar

Birck and NCN Publications

The role of nanotwin lamellae in enhancing thermal stability of nanostructured materials is examined. Nanostructured copper with varying densities of twins was generated by controlling the deformation strain rate during severe plastic deformation at cryogenic temperatures. While the nanostructured materials produced under cryogenic conditions are characteristically unstable even at room temperatures, their stability is markedly improved when a dense dispersion of nanotwins is introduced. Observations of the role of nanotwins in pinning grain and subgrain structures suggest an interfacial engineering approach to enhancing the stability of nanostructured alloys.

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Identification Of Multiple Oscillation States Of Carbon Nanotube Tipped Cantilevers Interacting With Surfaces In Dynamic Atomic Force Microscopy, Mark Strus, Arvind Raman Jan 2009

Identification Of Multiple Oscillation States Of Carbon Nanotube Tipped Cantilevers Interacting With Surfaces In Dynamic Atomic Force Microscopy, Mark Strus, Arvind Raman

Birck and NCN Publications

Carbon nanotubes (CNTs) have gained increased interest in dynamic atomic force microscopy (dAFM) as sharp, flexible, conducting, nonreactive tips for high-resolution imaging, oxidation lithography, and electrostatic force microscopy. By means of theory and experiments we lay out a map of several distinct tapping mode AFM oscillation states for CNT tipped AFM cantilevers: namely, noncontact attractive regime oscillation, intermittent contact with CNT slipping or pinning, or permanent contact with the CNT in point or line contact with the surface while the cantilever oscillates with large amplitude. Each state represents fundamentally different origins of CNT-surface interactions, CNT tip-substrate dissipation, and phase contrast …

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Generalization Of Acid Properties, Brahim Medjahed, Mourad Ouzzani, Ahmed Elmagarmid Jan 2009

Generalization Of Acid Properties, Brahim Medjahed, Mourad Ouzzani, Ahmed Elmagarmid

Cyber Center Publications

ACID (Atomicity, Consistency, Isolation, and Durability) is a set of properties that guarantee the reliability of database transactions [2]. ACID properties were initially developed with traditional, business-oriented applications (e.g., banking) in mind. Hence, they do not fully support the functional and performance requirements of advanced database applications such as computer-aided design, computer-aided manufacturing, office automation, network management, multidatabases, and mobile databases. For instance, transactions in computer-aided design applications are generally of long duration and preserving the traditional ACID properties in such transactions would require locking resources for long periods of time. This has lead to the generalization of ACID properties …

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Orbital Start Effect And Quantum Confinement Transition Of Donors In Silicon, Rajib Rahman, G. P. Lansbergen, Seung H. Park, J. Verdujin, Gerhard Klimeck, S. Rogge, Lloyd C. L. Hollenberg Jan 2009

Orbital Start Effect And Quantum Confinement Transition Of Donors In Silicon, Rajib Rahman, G. P. Lansbergen, Seung H. Park, J. Verdujin, Gerhard Klimeck, S. Rogge, Lloyd C. L. Hollenberg

Birck and NCN Publications

Adiabatic shuttling of single impurity bound electrons to gate-induced surface states in semiconductors has attracted much attention in recent times, mostly in the context of solid-state quantum computer architecture. A recent transport spectroscopy experiment for the first time was able to probe the Stark shifted spectrum of a single donor in silicon buried close to a gate. Here, we present the full theoretical model involving large-scale quantum mechanical simulations that was used to compute the Stark shifted donor states in order to interpret the experimental data. Use of atomistic tight-binding technique on a domain of over a million atoms helped …

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Atomistic Full-Band Simulations Of Si Nanowire Transistors: Effects Of Electron-Phonon Scattering, Mathieu Luisier, Gerhard Klimeck Jan 2009

Atomistic Full-Band Simulations Of Si Nanowire Transistors: Effects Of Electron-Phonon Scattering, Mathieu Luisier, Gerhard Klimeck

Birck and NCN Publications

An atomistic full-band quantum transport simulator has been developed to study three-dimensional Si nanowire field-effect transistors (FETs) in the presence of electron-phonon scattering. The Non-equilibrium Green's Function (NEGF) formalism is solved in a nearest-neighbor sp(3)d(5)s* tight-binding basis. The scattering self-energies are derived in the self-consistent Born approximation to inelastically couple the full electron and phonon energy spectra. The band dispersion and the eigenmodes of the confined phonons are calculated using a dynamical matrix that includes the bond and angle deformations of the nanowires. The optimization of the numerical algorithms and the parallelization of the NEGF scheme enable the investigation of …

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Location Privacy In Moving-Object Environments, Dan Lin, Elisa Bertino, Reynold Cheng, Sunil Prabhakar Jan 2009

Location Privacy In Moving-Object Environments, Dan Lin, Elisa Bertino, Reynold Cheng, Sunil Prabhakar

Cyber Center Publications

The expanding use of location-based services has profound implications on the privacy of personal information. If no adequate protection is adopted, information about movements of specific individuals could be disclosed to unauthorized subjects or organizations, thus resulting in privacy breaches. In this paper, we propose a framework for preserving location privacy in moving-object environments. Our approach is based on the idea of sending to the service provider suitably modified location information. Such modifications, that include transformations like scaling, are performed by agents interposed between users and service providers. Agents execute data transformation and the service provider directly processes the transformed …

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A Stochastic Collocation Approach To Bayesian Inference In Inverse Problems, Youssef Marzouk, Dongbin Xiu Jan 2009

A Stochastic Collocation Approach To Bayesian Inference In Inverse Problems, Youssef Marzouk, Dongbin Xiu

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

We present an efficient numerical strategy for the Bayesian solution of inverse problems. Stochastic collocation methods, based on generalized polynomial chaos (gPC), are used to construct a polynomial approximation of the forward solution over the support of the prior distribution. This approximation then defines a surrogate posterior probability density that can be evaluated repeatedly at minimal computational cost. The ability to simulate a large number of samples from the posterior distribution results in very accurate estimates of the inverse solution and its associated uncertainty. Combined with high accuracy of the gPC-based forward solver, the new algorithm can provide great efficiency …

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Coarse Grain Modeling Of Spall Failure In Molecular Crystals: Role Of Intra-Molecular Degrees Of Freedom, Karen Lynch, Alexander Thompson, Alejandro Strachan Jan 2009

Coarse Grain Modeling Of Spall Failure In Molecular Crystals: Role Of Intra-Molecular Degrees Of Freedom, Karen Lynch, Alexander Thompson, Alejandro Strachan

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

We use a recently developed thermodynamically accurate mesodynamical method (Strachan and Holian 2005 Phys. Rev. Lett. 94 014301) where groups of atoms are represented by mesoparticles to characterize the shock compression and dynamical failure (spall) of a model molecular crystal. We characterize how the temperature rise caused by the shockwave depends on the specific heat of the degrees of freedom (DoFs) internal to the mesoparticles (Cint) and the strength of the coupling between the internal DoFs and the mesoparticles. We find that the temperature of the shocked material decreases with increasing Cint and decreasing coupling and quantify these effects. Our …

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A Generalized Polynomial Chaos Based Ensemble Kalman Filter, Jia Li, Dongbin Xiu Jan 2009

A Generalized Polynomial Chaos Based Ensemble Kalman Filter, Jia Li, Dongbin Xiu

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

As one of the most adopted sequential data assimilation methods in many areas, especially those involving complex nonlinear dynamics, the ensemble Kalman filter (EnKF) has been under extensive investigation regarding its properties and efficiency. Compared to other variants of the Kalman filter (KF), EnKF is straightforward to implement, as it employs random ensembles to represent solution states. This, however, introduces sampling errors that affect the accuracy of EnKF in a negative manner. Though sampling errors can be easily reduced by using a large number of samples, in practice this is undesirable as each ensemble member is a solution of the …

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Private Queries And Trajectory Anonymization: A Dual Perspective On Location Privacy, Gabriel Ghinita Jan 2009

Private Queries And Trajectory Anonymization: A Dual Perspective On Location Privacy, Gabriel Ghinita

Cyber Center Publications

The emergence of mobile devices with Internet connectivity (e.g., Wi-Fi) and global positioning capabilities (e.g., GPS) have triggered the widespread development of location-based applications. For instance, users are able to ask queries about points of interest in their proximity. Furthermore, users can act as mobile sensors to monitor traffic flow, or levels of air pollution. However, such applications require users to disclose their locations, which raises serious privacy concerns. With knowledge of user locations, a malicious attacker can infer sensitive information, such as alternative lifestyles or political affiliations. Preserving location privacy is an essential requirement towards the successful deployment of …

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Advancing Nanoelectronic Device Modeling Through Peta-Scale Computing And Deployment On Nanohub, Benjamin Haley, Sunhee Lee, Mathieu Luisier, Hoon Ryu, Faisal Saied, Steven Clark, Hansang Bae, Gerhard Klimeck Jan 2009

Advancing Nanoelectronic Device Modeling Through Peta-Scale Computing And Deployment On Nanohub, Benjamin Haley, Sunhee Lee, Mathieu Luisier, Hoon Ryu, Faisal Saied, Steven Clark, Hansang Bae, Gerhard Klimeck

Birck and NCN Publications

Recent improvements to existing HPC codes NEMO 3-D and OMEN, combined with access to peta-scale computing resources, have enabled realistic device engineering simulations that were previously infeasible. NEMO 3-D can now simulate 1 billion atom systems, and, using 3D spatial decomposition, scale to 32768 cores. Simulation time for the band structure of an experimental P doped Si quantum computing device fell from 40 minutes to I minute. OMEN can perform fully quantum mechanical transport calculations for real-word UTB FETs on 147,456 cores in roughly 5 minutes. Both of these tools power simulation engines on the nanoHUB, giving the community access …

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Query Mesh: Multiroute, Rimma Nehme, Karen Works, Elke Rundensteiner, Elisa Bertino Jan 2009

Query Mesh: Multiroute, Rimma Nehme, Karen Works, Elke Rundensteiner, Elisa Bertino

Cyber Center Publications

We propose to demonstrate a practical alternative approach to the current state-of-the-art query processing techniques, called the “Query Mesh” (or QM, for short). The main idea of QM is to compute multiple routes (i.e., query plans)1, each designed for a particular subset of data with distinct statistical properties. Based on the execution routes and the data characteristics, a classifier model is induced and is used to partition new data tuples to assign the best routes for their processing. We propose to demonstrate the QM framework in the streaming context using our demo application, called the “Ubi-City”. We will illustrate the …

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Parallel Reactive Molecular Dynamics: Numerical Methods And Algorithmic Techniques, Hasan Metin Aktulga, Joseph C. Fogarty, Sagar A. Pandit, Ananth Y. Grama Jan 2009

Parallel Reactive Molecular Dynamics: Numerical Methods And Algorithmic Techniques, Hasan Metin Aktulga, Joseph C. Fogarty, Sagar A. Pandit, Ananth Y. Grama

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

No abstract provided.

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A Hierarchical Approach To Model Web Query Interfaces For Web Source Integration, Thomas Kabisch, Eduard Dragut, Clement Yu, Ulf Leser Jan 2009

A Hierarchical Approach To Model Web Query Interfaces For Web Source Integration, Thomas Kabisch, Eduard Dragut, Clement Yu, Ulf Leser

Cyber Center Publications

Much data in the Web is hidden behind Web query interfaces. In most cases the only means to "surface" the content of a Web database is by formulating complex queries on such interfaces. Applications such as Deep Web crawling and Web database integration require an automatic usage of these interfaces. Therefore, an important problem to be addressed is the automatic extraction of query interfaces into an appropriate model. We hypothesize the existence of a set of domain-independent "commonsense design rules" that guides the creation of Web query interfaces. These rules transform query interfaces into schema trees. In this paper we …

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The Plant Ionome Coming Into Focus, Lorraine Williams, David Salt Jan 2009

The Plant Ionome Coming Into Focus, Lorraine Williams, David Salt

Cyber Center Publications

92 elements have been identified on earth and 17 of these are known to be essential to all plants. The essential elements required in relatively large amounts (>0.1% of dry mass) are called macronutrients and include C, H, O, N, S, P, Ca, K, Mg. Those required in much smaller amounts (<0.01% of dry mass) are referred to as micronutrients or trace elements and include Ni, Mo, Cu, Zn, Mn, B, Fe, and Cl. Plant growth and development depends on a balanced supply of these essential elements and thus the plant has a range of homeostatic mechanisms operating to ensure that this is maintained. Beneficial elements which promote growth and may be essential to some taxa, include Na, Co, Al, Se and Si. Elements such as the heavy metal Cd and the metalloid As have no demonstrated biological function in plants, but are nevertheless taken up and cause severe toxicity in most plant species. The concept for this special issue is the plant ionome, a word coined to encompass all these elements and allow focussed discussion and investigations on the mechanisms that co-ordinately regulate these elements in response to genetic and environmental factors reviewed in Salt et al., 2008).

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Gold Nanorods As Contrast Agents For Biological Imaging: Optical Properties, Surface Conjugation And Photothermal Effects, Ling Tong, Qingshan Wei, Alexander Wei, Ji-Xin Cheng Jan 2009

Gold Nanorods As Contrast Agents For Biological Imaging: Optical Properties, Surface Conjugation And Photothermal Effects, Ling Tong, Qingshan Wei, Alexander Wei, Ji-Xin Cheng

Other Nanotechnology Publications

Gold nanorods (NRs) have plasmon-resonant absorption and scattering in the near-infrared (NIR) region, making them attractive probes for in vitro and in vivo imaging. In the cellular environment, NRs can provide scattering contrast for darkfield microscopy, or emit a strong two-photon luminescence due to plasmon-enhanced two-photon absorption. NRs have also been employed in biomedical imaging modalities such as optical coherence tomography or photoacoustic tomography. Careful control over surface chemistry enhances the capacity of NRs as biological imaging agents by enabling cell-specific targeting, and by increasing their dispersion stability and circulation lifetimes. NRs can also efficiently convert optical energy into heat, …

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Beyond K-Anonymity: A Decision Theoretic Framework For Assessing Privacy Risk, Guy Lebanon, Monica Scannapieco, Mohamed Fouad, Elisa Bertino Jan 2009

Beyond K-Anonymity: A Decision Theoretic Framework For Assessing Privacy Risk, Guy Lebanon, Monica Scannapieco, Mohamed Fouad, Elisa Bertino

Cyber Center Publications

An important issue any organization or individual has to face when managing data containing sensitive information, is the risk that can be incurred when releasing such data. Even though data may be sanitized before being released, it is still possible for an adversary to reconstruct the original data using additional information thus resulting in privacy violations. To date, however, a systematic approach to quantify such risks is not available. In this paper we develop a framework, based on statistical decision theory, that assesses the relationship between the disclosed data and the resulting privacy risk. We model the problem of deciding …

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Performance Related Specifications (Prs) For Concrete Pavements In Indiana, Volume 1: Executive Summary, Cole Graveen, Eric Max Falker, Micah Beaver, Narayanan Neithalath, W. Jason Weiss, J. Olek, Tommy Edward Nantung, Victor Lee Gallivan Jan 2009

Performance Related Specifications (Prs) For Concrete Pavements In Indiana, Volume 1: Executive Summary, Cole Graveen, Eric Max Falker, Micah Beaver, Narayanan Neithalath, W. Jason Weiss, J. Olek, Tommy Edward Nantung, Victor Lee Gallivan

JTRP Technical Reports

Performance-Related Specifications (PRS) are specifications that base pavement acceptance and pay adjustment on the projected performance and predicted life-cycle cost (LCC) for a specific pavement. PRS relate measurable quality characteristics with pavement performance through computer simulations that incorporate physical distress models. Previously, work at ERES consultants by Darter and co-workers developed prototype PRS for jointed plain portland cement concrete pavements (PCC) through Federal Highway Administration (FHWA) through a series of research projects. However, before this research program began, pavements have not been constructed using these specifications. This report describes the Indiana Department of Transportation’s (INDOT) experience with developing and implementing …

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Performance Related Specifications (Prs) For Concrete Pavements In Indiana, Volume 2: Technical Report, Cole Graveen, Eric Max Falker, Micah Beaver, Narayanan Neithalath, W. Jason Weiss, J. Olek, Tommy Edward Nantung, Victor Lee Gallivan Jan 2009

Performance Related Specifications (Prs) For Concrete Pavements In Indiana, Volume 2: Technical Report, Cole Graveen, Eric Max Falker, Micah Beaver, Narayanan Neithalath, W. Jason Weiss, J. Olek, Tommy Edward Nantung, Victor Lee Gallivan

JTRP Technical Reports

Performance-Related Specifications (PRS) are specifications that base pavement acceptance and pay adjustment on the projected performance and predicted life-cycle cost (LCC) for a specific pavement. PRS relate measurable quality characteristics with pavement performance through computer simulations that incorporate physical distress models. Previously, work at ERES consultants by Darter and co-workers developed prototype PRS for jointed plain portland cement concrete pavements (PCC) through Federal Highway Administration (FHWA) through a series of research projects. However, before this research program began, pavements have not been constructed using these specifications. This report describes the Indiana Department of Transportation’s (INDOT) experience with developing and implementing …

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Synthesis Of Best Practices In Transportation Security, Volume I: Vulnerability Assessment, Haritha Reddy Venna, Jon D. Fricker Jan 2009

Synthesis Of Best Practices In Transportation Security, Volume I: Vulnerability Assessment, Haritha Reddy Venna, Jon D. Fricker

JTRP Technical Reports

Part I of the research focused on developing a methodology to identify and evaluate the most critical and vulnerable INDOT assets. This method aims at obtaining an index that reflects the vulnerability and criticality of an asset on the basis of multiple performance criteria. This methodology was tested on the seven INDOT districts. Because not all the factors that influence the vulnerability do have same weight, the analytical hierarchical process is used to obtain the weights for the criteria. Countermeasures are suggested as a part of the research to reduce the vulnerability of a given asset based on its relevant …

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Mechanistic Evaluation Of Rubblized Pcc Pavements, Yigong Ji Jan 2009

Mechanistic Evaluation Of Rubblized Pcc Pavements, Yigong Ji

JTRP Technical Reports

This report presents a mechanistic approach and procedures for determining layer coefficients to characterize the in-situ behaviors of rubblized pavements. This procedure was developed based on the 1993 AASHTO Pavement Design Guide utilizing Falling Weight Deflectometer (FWD) testing and in-place simulation using back-calculation layer modulus. In order to evaluate the rubblized pavement systematically, twelve constructed pavement sections were extensively tested by FWD annually after construction. The FWD data was processed using the proposed mechanistic procedure. In addition, statistical analysis was conducted to compare the pavement structure parameters each year, including layer coefficient and in-situ resilient modulus using Analysis of Variance …

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