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2012

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Full-Text Articles in Engineering

Load-Relaxation Properties Of The Human Trunk In Response To Prolonged Flexion: Measuring And Modeling The Effect Of Flexion Angle, Nima Toosizadeh, Maury A. Nussbaum, Babak Bazrgari, Michael L. Madigan Nov 2012

Load-Relaxation Properties Of The Human Trunk In Response To Prolonged Flexion: Measuring And Modeling The Effect Of Flexion Angle, Nima Toosizadeh, Maury A. Nussbaum, Babak Bazrgari, Michael L. Madigan

Biomedical Engineering Faculty Publications

Experimental studies suggest that prolonged trunk flexion reduces passive support of the spine. To understand alterations of the synergy between active and passive tissues following such loadings, several studies have assessed the time-dependent behavior of passive tissues including those within spinal motion segments and muscles. Yet, there remain limitations regarding load-relaxation of the lumbar spine in response to flexion exposures and the influence of different flexion angles. Ten healthy participants were exposed for 16 min to each of five magnitudes of lumbar flexion specified relative to individual flexion-relaxation angles (i.e., 30, 40, 60, 80, and 100%), during which lumbar flexion …


Environmental Systems I - University Of Illinois, Urbana, Ximing Cai Oct 2012

Environmental Systems I - University Of Illinois, Urbana, Ximing Cai

All ECSTATIC Materials

Undergraduate course in environmental systems at University of Illinois, Urbana in Fall 2012.


A Digital X-Ray Tomosynthesis Coupled Near Infrared Spectral Tomography System For Dual-Modality Breast Imaging, Venkataramanan Krishnaswamy, Kelly E. Michaelsen, Brian W. Pogue, Steven P. Poplack, Ian Shaw, Ken Defrietas, Ken Brooks, Keith D. Paulsen Aug 2012

A Digital X-Ray Tomosynthesis Coupled Near Infrared Spectral Tomography System For Dual-Modality Breast Imaging, Venkataramanan Krishnaswamy, Kelly E. Michaelsen, Brian W. Pogue, Steven P. Poplack, Ian Shaw, Ken Defrietas, Ken Brooks, Keith D. Paulsen

Dartmouth Scholarship

A Near Infrared Spectral Tomography (NIRST) system has been developed and integrated into a commercial Digital Breast Tomosynthesis (DBT) scanner to allow structural and functional imaging of breast in vivo. The NIRST instrument uses an 8-wavelength continuous wave (CW) laser-based scanning source assembly and a 75-element silicon photodiode solid-state detector panel to produce dense spectral and spatial projection data from which spectrally constrained 3D tomographic images of tissue chromophores are produced. Integration of the optical imaging system into the DBT scanner allows direct co-registration of the optical and DBT images, while also facilitating the synergistic use of x-ray contrast as …


Improved Tumor Contrast Achieved By Single Time Point Dual-Reporter Fluorescence Imaging, Kenneth M. Tichauer, Kimberley S. Samkoe, Kristian J. Sexton, Jason R. Gunn, Tayyaba Hasan, Brian W. Pogue May 2012

Improved Tumor Contrast Achieved By Single Time Point Dual-Reporter Fluorescence Imaging, Kenneth M. Tichauer, Kimberley S. Samkoe, Kristian J. Sexton, Jason R. Gunn, Tayyaba Hasan, Brian W. Pogue

Dartmouth Scholarship

In this study, we demonstrate a method to quantify biomarker expression that uses an exogenous dual-reporter imaging approach to improve tumor signal detection. The uptake of two fluorophores, one nonspecific and one targeted to the epidermal growth factor receptor (EGFR), were imaged at 1 h in three types of xenograft tumors spanning a range of EGFR expression levels (n  =  6 in each group). Using this dual-reporter imaging methodology, tumor contrast-to-noise ratio was amplified by >6 times at 1 h postinjection and >2 times at 24 h. Furthermore, by as early as 20 min postinjection, the dual-reporter imaging signal …


A Review Of National Msw Generation Assessments In The United States, David J. Tonjes, Krista L. Greene Jan 2012

A Review Of National Msw Generation Assessments In The United States, David J. Tonjes, Krista L. Greene

Technology & Society Faculty Publications

Municipal solid waste (MSW) is generated in very large quantities (probably, between 200 and 400 million tonnes per year) in the United States (US). MSW is generated at millions of places and there is no one precise, general definition for MSW that is generally applied, despite US Environmental Protection Agency efforts. As an element of both commerce and politics, reporting may be framed towards particular ends. Therefore, the two best known assessments of the quantity of US MSW production differ by approximately 50%. The assessors understand some of the reasons for the differences, but our analysis suggests that there are …


Methamphetamine Administration Targets Multiple Immune Subsets And Induces Phenotypic Alterations Suggestive Of Immunosuppression., Robert Z. Harms, Brenda M. Morsey, Craig W. Boyer, Howard S. Fox, Nora E. Sarvetnick Jan 2012

Methamphetamine Administration Targets Multiple Immune Subsets And Induces Phenotypic Alterations Suggestive Of Immunosuppression., Robert Z. Harms, Brenda M. Morsey, Craig W. Boyer, Howard S. Fox, Nora E. Sarvetnick

Journal Articles: Regenerative Medicine

Methamphetamine (Meth) is a widely abused stimulant and its users are at increased risk for multiple infectious diseases. To determine the impact of meth on the immune system, we utilized a murine model that simulates the process of meth consumption in a typical addict. Our phenotypic analysis of leukocytes from this dose escalation model revealed that meth affected key immune subsets. Meth administration led to a decrease in abundance of natural killer (NK) cells and the remaining NK cells possessed a phenotype suggesting reduced responsiveness. Dendritic cells (DCs) and Gr-1(high) monocytes/macrophages were also decreased in abundance while Gr-1(low) monocytes/macrophages appear …


Class A Prediction Of A Piled Relieving Slab Using Uncoupled Models, David Oliveira, Dan Gorman, Frances Badelow Jan 2012

Class A Prediction Of A Piled Relieving Slab Using Uncoupled Models, David Oliveira, Dan Gorman, Frances Badelow

Faculty of Engineering - Papers (Archive)

Construction of the new Windsor Road on/off ramps, part of the M2 Upgrade project, required limiting the loads and movements imposed on existing precast concrete walls so that no additional pressure was applied as a result of the new construction works. This was necessary due to possible structural deficiencies of some of the existing reinforced concrete elements. A piled relieving slab was adopted as the final solution to support the reinforced soil wall ramps and a comprehensive soil-structure interaction assessment was carried out in order to predict the pile head deflections and assess potential loading of the existing walls. A …


Robust Designs For Poisson Regression Models, J M. Mcgree, J A. Eccleston Jan 2012

Robust Designs For Poisson Regression Models, J M. Mcgree, J A. Eccleston

Faculty of Engineering and Information Sciences - Papers: Part A

We consider the problem of how to construct robust designs for Poisson regression models. An analytical expression is derived for robust designs for first-order Poisson regression models where uncertainty exists in the prior parameter estimates. Given cer- tain constraints in the methodology, it may be necessary to extend the robust designs for implementation in practical experiments. With these extensions, our methodology con- structs designs which perform similarly, in terms of estimation, to current techniques, and offers the solution in a more timely manner. We further apply this analytic result to cases where uncertainty exists in the linear predictor. The application …


Waypoints On A Journey Of Discovery: Mental Models In Human Environment Interactions, Timothy Lynam, Raphael Mathevet, Michel Etienne, Samantha Stone-Jovicich, Anne Leitch, Nathalie Jones, Helen Ross, Derick Du Toit, Sharon Pollard, Harry Biggs, Pascal Perez Jan 2012

Waypoints On A Journey Of Discovery: Mental Models In Human Environment Interactions, Timothy Lynam, Raphael Mathevet, Michel Etienne, Samantha Stone-Jovicich, Anne Leitch, Nathalie Jones, Helen Ross, Derick Du Toit, Sharon Pollard, Harry Biggs, Pascal Perez

SMART Infrastructure Facility - Papers

Although the broad concept of mental models is gaining currency as a way to explore the link between how people think and interact with their world, this concept is limited by a theoretical and practical understanding of how it can be applied in the study of human-environment relationships. Tools and processes are needed to be able to elicit and analyze mental models. Because mental models are not directly observable, it is also important to understand how the application of any tools and processes affects what is measured. Equally important are the needs to be clear on the intent of the …


Theory, Figures Of Merit, And Design Recipe Of The Plasmonic Structure Composed Of A Nano-Slit Aperture Surrounded By Surface Corrugations, Guangyuan Li, Feng Xiao, Kun Li, Kamal Alameh, Anshi Xu Jan 2012

Theory, Figures Of Merit, And Design Recipe Of The Plasmonic Structure Composed Of A Nano-Slit Aperture Surrounded By Surface Corrugations, Guangyuan Li, Feng Xiao, Kun Li, Kamal Alameh, Anshi Xu

Research outputs 2012

We theoretically investigate a widely-used plasmonic structure composed of a nano-slit aperture surrounded by surface corrugations. A systematical semi-analytical theory in form of two nested coupled-mode models is developed to provide intuitive physical pictures. Based on the theory, figures of merit (FoMs) of the structures designed for normal and for oblique incidence/beaming are defined for the first time to incorporate the interlinks among key structural parameters, making global optimization simple and efficient. Both the theory and the FoMs are quantitatively validated with exhaustive calculations and shown to be highly accurate on performance prediction and structural optimization. With the theory and …


Modeling Of Low Coherence Interferometry Using Broadband Multi-Gaussian Light Sources, Paul Jansz, Steven Richardson, Graham Wild, Steven Hinckley Jan 2012

Modeling Of Low Coherence Interferometry Using Broadband Multi-Gaussian Light Sources, Paul Jansz, Steven Richardson, Graham Wild, Steven Hinckley

Research outputs 2012

Using a low coherence interferometry (LCI) model, a comparison of broadband single-Gaussian and multi-Gaussian light sources has been undertaken. For single-Gaussian sources, the axial resolution improves with the source bandwidth, confirming the coherence length relation that the resolution for single Gaussian sources improves with increasing spectral bandwidth. However, narrow bandwidth light sources result in interferograms with overlapping strata peaks and the loss of individual strata information. For multiple-Gaussian sources with the same bandwidth, spectral side lobes increase, reducing A-scan reliability to show accurate layer information without eliminating the side lobes. The simulations show the conditions needed for the resolution of …


Unidirectionally Optical Coupling From Free Space Into Silicon Waveguide With Wide Flat-Top Angular Efficiency, K Li, G Li, Feng Xiao, Fan Lu, Zhonghua Wang, A Xu Jan 2012

Unidirectionally Optical Coupling From Free Space Into Silicon Waveguide With Wide Flat-Top Angular Efficiency, K Li, G Li, Feng Xiao, Fan Lu, Zhonghua Wang, A Xu

Research outputs 2012

A grating coupling scheme from free-space light into silicon waveguide with a remarkable property of wide flat-top angular efficiency is proposed and theoretically investigated. The coupling structure is composed of two cascaded gratings with a proper distance between their peak angular efficiencies. A quantitative semi-analytical theory based on coupled-mode models is developed for performance prediction and validated with the fully vectorial aperiodic Fourier modal method (a-FMM). With the theory, wide flat-top angular response is achieved and the conditions are pointed out. Proof-of-principle demonstrations show that the -1 dB angular widtha figure of merit to evaluate the flat-top performanceis broadened to …


Marginalized Exponential Random Graph Models, Thomas F. Suesse Jan 2012

Marginalized Exponential Random Graph Models, Thomas F. Suesse

Faculty of Engineering and Information Sciences - Papers: Part A

Exponential random graph models (ERGMs) are a popular tool for modeling social networks representing relational data, such as working relationships or friendships. Data on exogenous variables relating to participants in the network, such as gender or age, are also often collected. ERGMs allow modeling of the effects of such exogenous variables on the joint distribution, specified by the ERGM, but not on the marginal probabilities of observing a relationship. In this article, we consider an approach to modeling a network that uses an ERGM for the joint distribution of the network, but then marginally constrains the fit to agree with …


Estimation Of Breeding Values For Mean And Dispersion, Their Variance And Correlation Using Double Hierarchical Generalized Linear Models, M Felleki, D Lee, Y Lee, A R. Gilmour, L Ronnegard Jan 2012

Estimation Of Breeding Values For Mean And Dispersion, Their Variance And Correlation Using Double Hierarchical Generalized Linear Models, M Felleki, D Lee, Y Lee, A R. Gilmour, L Ronnegard

Faculty of Engineering and Information Sciences - Papers: Part A

The possibility of breeding for uniform individuals by selecting animals expressing a small response to environment has been studied extensively in animal breeding. Bayesian methods for fitting models with genetic components in the residual variance have been developed for this purpose, but have limitations due to the computational demands. We use the hierarchical (h)-likelihood from the theory of double hierarchical generalized linear models (DHGLM) to derive an estimation algorithm that is computationally feasible for large datasets. Random effects for both the mean and residual variance parts of the model are estimated together with their variance/covariance components. An important feature of …


Colonel Blotto Games And Lancaster's Equations: A Novel Military Modeling Combination, Andrew Collins, Patrick T. Hester Jan 2012

Colonel Blotto Games And Lancaster's Equations: A Novel Military Modeling Combination, Andrew Collins, Patrick T. Hester

VMASC Publications

Military strategists face a difficult task when engaged in a battle against an adversarial force. They have to predict both what tactics their opponent will employ and the outcomes of any resultant conflicts in order to make the best decision about their actions. Game theory has been the dominant technique used by analysts to investigate the possible actions that an enemy will employ. Traditional game theory can be augmented by use of Lanchester equations, a set of differential equations used to determine the outcome of a conflict. This paper demonstrates a novel combination of game theory and Lanchester equations using …


The Reduction Of Storm Surge By Vegetation Canopies: Three-Dimensional Simulations, Y. Peter Sheng, Andrew Lapetina, Gangfeng Ma Jan 2012

The Reduction Of Storm Surge By Vegetation Canopies: Three-Dimensional Simulations, Y. Peter Sheng, Andrew Lapetina, Gangfeng Ma

Civil & Environmental Engineering Faculty Publications

Significant buffering of storm surges by vegetation canopies has been suggested by limited observations and simple numerical studies, particularly following recent Hurricanes Katrina, Rita, and Wilma. Here we simulate storm surge and inundation over idealized topographies using a three-dimensional vegetation-resolving storm surge model coupled to a shallow water wave model and show that a sufficiently wide and tall vegetation canopy reduces inundation on land by 5 to 40 percent, depending upon various storm and canopy parameters. Effectiveness of the vegetation in dissipating storm surge and inundation depends on the intensity and forward speed of the hurricane, as well as the …


Estimation In Autoregressive Population Models, Thomas Suesse Jan 2012

Estimation In Autoregressive Population Models, Thomas Suesse

Faculty of Engineering and Information Sciences - Papers: Part A

Autoregressive (AR) models for spatial and social interaction have been proposed by many authors. A sample of units is obtained and the model is applied to this sample. Estimation methods such as the maximum likelihood method (ML) have been employed and investigated in the literature. The main assumption is that a response depends on other responses, when these units interact. Some of those units will be in the sample and some in the non-sample. Therefore the model should apply to the whole population rather to the sample only. Under such a population model, the marginal model for the responses of …


Exponential-Family Random Graph Models For Valued Networks, Pavel N. Krivitsky Jan 2012

Exponential-Family Random Graph Models For Valued Networks, Pavel N. Krivitsky

Faculty of Engineering and Information Sciences - Papers: Part A

Exponential-family random graph models (ERGMs) provide a principled and flexible way to model and simulate features common in social networks, such as propensities for homophily, mutuality, and friend-of-a- friend triad closure, through choice of model terms (sufficient statistics). However, those ERGMs modeling the more complex features have, to date, been limited to binary data: presence or absence of ties. Thus, analysis of valued networks, such as those where counts, measurements, or ranks are observed, has necessitated dichotomizing them, losing information and introducing biases. In this work, we generalize ERGMs to valued networks. Focusing on modeling counts, we formulate an ERGM …