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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Intelligent hazard identification: Dynamic visibility measurement of construction equipment operators

Ray, Soumitry J. 26 March 2014 (has links)
Struck-by fatalities involving heavy equipment such as trucks and cranes accounted for 24.6% of the fatalities between 1997-2007 in the construction industry. Limited visibility due to blind spots and travel in reverse direction are the primary causes of these fatalities. Blind spots are spaces surrounding an equipment that are invisible to the equipment operator. Thus, a hazard is posed to the ground personnel working in the blind spaces of an equipment operator. This research presents a novel approach to intelligently identify potential hazards posed to workers operating near an equipment by determining the visible and blind space regions of an equipment operator in real-time. A depth camera is used to estimate the head posture of the equipment operator and continuously track the head location and orientation using Random Forests algorithm. The head posture information is then integrated with point cloud data of the construction equipment to determine both the visible and the blindspots region of the equipment operator using Ray-Casting algorithm. Simulation and field experiments were carried out to validate this approach in controlled and uncontrolled environment respectively. Research findings demonstrate the potential of this approach to enhance safety performance by detecting hazardous proximity situations.
172

Traffic-related Pollution Exposure Assessment of Fulton County and Atlanta Public Schools (K-12) in Proximity to Major Highways and Expressways

Carter, David 12 August 2014 (has links)
ABSTRACT ROSS CARTER Traffic-related Pollution Exposure Assessment of Fulton County and Atlanta Public Schools (K-12) in Proximity to Major Highways and Expressways Background: A number of studies have linked traffic-related pollutant exposures to asthma in children. Health conditions such as asthma can contribute to school absenteeism and missed learning opportunities as well as place a major burden on health resources. Although children spend a significant amount of time in school, few states have adopted school siting policies that prevent the placement of schools near major highways. Furthermore, schools often fail to take appropriate steps (e.g. adequate HVAC and air filters) to address indoor air quality concerns for students. The study was designed to identify the number of schools and the number of children in Fulton County and Atlanta Public Schools that attend schools in proximity to major highways and expressways where they are likely to have greater exposure to traffic pollution. The results of this study can be used to build an evidence base for stricter school siting guidelines, for planning safe routes to school, and for mitigation strategies to limit pollutant exposures for children who attend high-risk schools. Methods: Highway, expressway, county, and school shapefiles were overlaid using ArcMap in ArcGIS version 10.1 (ERSI, USA). A circular buffer with radius 0.5 mile (~ 800 m) was created for each school. ArcMap geospatial tools were used to identify major highways and expressways with these buffers. Results: A total of 119 of the 225 schools in Fulton County and Atlanta Public school districts were identified as being located within 0.5 miles of a major highway or expressway. Of the 119 schools meeting the intersection criteria, 72.2% (86 of 119 schools) were designated Title I. Conclusion: Approximately half of schools were located within 0.5 miles of a major highway or expressway. This may result in elevated levels of traffic-related air pollution on the school campuses and potential increased exposure for students. Proper air filter selection, HVAC maintenance, and air quality programs as well as land use, planning, and assessment measures are recommended for these schools to help mitigate exposures.
173

DNA-Assisted Immunoassays for High-Performance Protein Analyses

Yan, Junhong January 2014 (has links)
Proteins play important roles in most cellular functions, such as, replication, transcription regulation, signal transduction, for catalyzing chemical reaction, etc. Technologies developed to identify proteins rely either on observing their own properties such as charge, size, mass to charge ratio or sequence composition; or on using affinity reagents that recognize specific protein targets. Immunoassays utilizing functionalized affinity reagents are powerful for targeted proteomics. Among them, DNA-assisted immunoassays in which affinity reagents are labeled with DNA molecules, offer some unique advantages. In this thesis, I will present works to improve current DNA-assisted immunoassays such as proximity ligation assays (PLA), as well as to take advantage of DNA reactions to adress other problems. In paper I, a new solid support (MBC-Ts) was functionalized with antibodies and used in the solid-phase PLA for detection of VEGF. The assay using MBC-Ts was compared among the commercially available solid supports in different matrices and it was shown to exhibit enhanced limit of detection in complex matrices. In paper II, a two-step protocol was described to prepare high-quality probes used in homogeneous and in situ PLA by purifying DNA-labeled affinity reagents from unconjugated affinity reagents and excess oligonucleotides. In paper III, PLA was applied on a capillary western blotting instrument so that both the sensitivity and specificity of the original assay were improved. In paper IV, a new method was introduced to profile protein components in individual protein complexes by DNA-barcoded antibodies. This method has been used to profile protein complexes such as surface proteins on individual secreted vesicles.
174

Nonlinear pose control and estimation for space proximity operations: an approach based on dual quaternions

Salgueiro Filipe, Nuno Ricardo 12 January 2015 (has links)
The term proximity operations has been widely used in recent years to describe a wide range of space missions that require a spacecraft to remain close to another space object. Such missions include, for example, the inspection, health monitoring, surveillance, servicing, and refueling of a space asset by another spacecraft. One of the biggest challenges in autonomous space proximity operations, either cooperative or uncooperative, is the need to autonomously and accurately track time-varying relative position and attitude references, i.e., pose references, with respect to a moving target, in order to avoid on-orbit collisions and achieve the overall mission goals. In addition, if the target spacecraft is uncooperative, the Guidance, Navigation, and Control (GNC) system of the chaser spacecraft must not rely on any help from the target spacecraft. In this case, vision-based sensors, such as cameras, are typically used to measure the relative pose between the spacecraft. Although vision-based sensors have several attractive properties, they introduce new challenges, such as no direct linear and angular velocity measurements, slow update rates, and high measurement noise. This dissertation investigates the problem of autonomously controlling and estimating the pose of a chaser spacecraft with respect to a moving target spacecraft, possibly uncooperative. Since this problem is inherently hard, the standard approach in the literature is to split the attitude-tracking problem from the position-tracking problem. Whereas the attitude-tracking problem is relatively simple, since the rotational motion is independent from the translational motion, the position-tracking problem is more complicated, as the translational motion depends on the rotational motion. Hence, whereas strong theoretical results exist for the attitude problem, the position problem typically requires additional assumptions. An alternative, more general approach to the pose control and estimation problems is to consider the fully coupled 6-DOF motion. However, fewer results exist that directly address this higher dimensional problem. The main contribution of this dissertation is to show that dual quaternions can be used to extend the theoretical results that exist for the attitude motion into analogous results for the combined position and attitude motion. Moreover, this dissertation shows that this can be accomplished by (almost) just replacing quaternions by dual quaternions in the original derivations. This is because dual quaternions are built on and are an extension of classical quaternions. Dual quaternions provide a compact representation of the pose of a frame with respect to another frame. Using this approach, three new results are presented in this dissertation. First, a pose-tracking controller that does not require relative linear and angular velocity measurements is derived with vision-based sensors in mind. Compared to existing literature, the proposed velocity-free pose-tracking controller guarantees that the pose of the chaser spacecraft will converge to the desired pose independently of the initial state, even if the reference motion is not sufficiently exciting. In addition, the convergence region does not depend on the gains of the controller. Second, a Dual Quaternion Multiplicative Extended Kalman Filter (DQ-MEKF) is developed from the highly successful Quaternion MEKF (Q-MEKF) as an alternative way to achieve pose-tracking without velocity measurements. Existing dual quaternion EKFs are additive, not multiplicative, and have two additional states. The DQ-MEKF is experimentally validated and compared with two conventional EKFs on the 5-DOF platform of the Autonomous Spacecraft Testing of Robotic Operations in Space (ASTROS) facility at the School of Aerospace Engineering at Georgia Tech. Finally, the velocity-free pose-tracking controller is compared qualitatively and quantitatively to a pose-tracking controller that uses the velocity estimates produced by the DQ-MEKF through a realistic proximity operations simulation. Third, a pose-tracking controller that does not require the mass and inertia matrix of the chaser satellite is suggested. This inertia-free controller takes into account the gravitational acceleration, the gravity-gradient torque, the perturbing acceleration due to Earth's oblateness, and constant -- but otherwise unknown -- disturbance forces and torques. Sufficient conditions on the reference pose are also given that guarantee the identification of the mass and inertia matrix of the satellite. Compared to the existing literature, this controller has only as many states as unknown elements and it does not require a priori known upper bounds on any states or parameters. Finally, the inertia-free pose-tracking controller and the DQ-MEKF are tested on a high-fidelity simulation of the 5-DOF platform of the ASTROS facility and also experimentally validated on the actual platform. The equations of motion of the 5-DOF platform, on which the high-fidelity simulation is based, are derived for three distinct cases: a 3-DOF case, a 5-DOF case, and a (2+1)-DOF case. Four real-time experiments were run on the platform. In the first, a sinusoidal reference attitude with respect to the inertial frame is tracked using VSCMGs. In the second, a constant reference attitude is maintained with respect to a target object using VSCMGs and measurements from a camera. In the third, the same sinusoidal reference attitude with respect to the inertial frame tracked in the first experiment is now tracked using cold-gas thrusters. Finally, in the fourth and last experiment, a time-varying 5-DOF reference pose with respect to the inertial frame is tracked using cold-gas thrusters.
175

Sme Networks As New Engines Of Economic Development And Innovativeness

Armatli Koroglu, Bilge 01 January 2004 (has links) (PDF)
This thesis is an attempt to search the relationship between development, innovativeness and networking. In recent regional development debates, regional networks of SMEs and regional knowledge potential have been emphasized as important components of development. In the context of the thesis, inter-regional networks of SMEs are analyzed as an alternative approach to the regionally bounded perspective. It is hypothesized that regional and inter-regional networks complement each other, and both of them play an important role in regional development and innovation processes. The thesis acquires the indicators for the increasing importance of external networks and innovation capacity in the globalisation era. Hence, the study explains the relative importance of spatial proximity in different types of networks, the positive and negative contributions of external networks to regional networks, and the contributions of regional, national and global networks to innovation activities of SMEs. The theoretical framework discussed in this thesis is based on the recent regional development models and contemporary networking and innovation studies. The main findings of this study contribute to this debate by modifying some of assumptions related to networking and innovation activities of SMEs. In the thesis, the method used for research is field survey, realized in three industrial regions. 131 SMEs have been involved in this survey in order to obtain a qualitative data about network and innovation behavior of SMEs in the sample regions.
176

Proximity Ligation Assays for Disease Biomarkers Analysis

Nong, Rachel Yuan January 2011 (has links)
One of the pressing needs in the field of disease biomarker discovery is new technologies that could allow high performance protein analysis in different types of clinical material, such as blood and solid tissues. This thesis includes four approaches that address important limitations of current technologies, thus enabling highly sensitive, specific and parallel protein measurements. Paper I describes a method for sensitive singleplex protein detection in complex biological samples, namely solid phase proximity ligation assay (SP-PLA). SP-PLA exhibited improved sensitivity compared to conventional sandwich immunoassays. We applied SP-PLA to validate the potential of GDF-15 as a biomarker for cardiovascular disease.   Paper II describes ProteinSeq, a multiplexed immunoassay based on the principle of SP-PLA, for parallel detection of 36 proteins using next-generation sequencing as readout. ProteinSeq exhibited improved sensitivity compared to multiplexed sandwich immunoassays, and the potential to achieve even higher levels of multiplexing while preserving a high sensitivity and specificity. We applied ProteinSeq to analyze 36 proteins, including one internal control, in 5 μl of plasma samples in a cohort of patients with cardiovascular disease and healthy controls. Paper III describes PLA-DTM, a strategy for recording all possible interactions between sets of proteins in clinical samples. Individual proteins and their interactions are first encoded to dual barcoded DNA by PLA, and the barcodes are interrogated by a method named dual tag microarray (DTM). We applied the method for studying interactions among protein members of the NFκB signaling pathway. Paper IV describes a novel probing strategy for analyzing individual biomolecules in solution or in situ. The technique employs a new class of probes for unfolding proximity ligation assays - uPLA probes. The probes are designed so that each probe set is sufficient in forming and replicating circular DNA reporter, without interactions among themselves when incubated with the sample. The uPLA probing strategy provides ease in the design of multiple probe sets in parallelized assays while enhancing the specificity of detection. We used the uPLA probes to detect various targets, including synthetic DNA and cancer-related transcripts in situ.
177

Subsurface utility engineering : a feasibility study and guideline for Naval Facilities Engineering Command : an independent research study ... /

Lockhart, Jason H. January 2004 (has links)
Thesis (M.S.)--Purdue University, 2004. / Available from National Technical Information Service, Springfield, Va., 2004. Includes bibliographical references (leaves 78-80). Also available online.
178

Digital media and the transnationalization of protests

Dahlberg-Grundberg, Michael January 2016 (has links)
Recent developments in communications technology have transformed how social movements might mobilize, and how they can organize their activities. This thesis explores some of the geographical consequences of the use of digital media for political activism. It does this by focusing on the transnationalization of protests. The aim is to analyse how movements with different organizational structures and political scopes are affected by their use of digital media. This is done with a specific focus on how digital media use influences or enables transnational modes of organization and activism. The thesis comprises four different case studies where each study examines a social movement with a specific organizational structure. There are, however, also important similarities between the movements. In each study, somewhat different perspectives and methodological approaches are used. Some of the methods used are semi-structured interviews, content analysis of written data (retrieved from Facebook as well as Twitter), and social network analysis. The analysis indicates that digital media do have a role in the transnationalization of protest. This role, however, differs depending on what type of social movement one studies. The organizational structure of social movements, together with their specific forms of digital media use, influences how the transnationalization of protests and movements is articulated and formed. In cases where a social movement has a hierarchical organizational structure, there is less transnationalization, whereas in social movements with a more non-hierarchical organizational structure one sees more transnationalization. The thesis concludes that the transnationalization of protests is affected by social movements’ organizational structure. The more decentralized the social movement, the more vibrant the transnational public. In order to explain how transnational social movements, using digital media, can emerge in cases where geographical distances might make such coalitions unlikely, the thesis introduces the notion of affectual proximity. This concept helps us understand how transnational social movements, connecting actors from all over the world, can emerge through digital media.
179

Modélisation des procédés pour la correction des effets de proximity en lithographie électronique / Process modeling for proximity effect correction in electron beam lithography

Figueiro, Thiago Rosa 19 January 2015 (has links)
Depuis l'apparition du premier circuit intégré, le nombre de composants constituant une puce électronique n'a cessé d'augmenter tandis que les dimensions des composants ont continuellement diminué. Pour chaque nouveau nœud technologique, les procédés de fabrication se sont complexifiés pour permettre cette réduction de taille. L'étape de lithographie est une des étapes la plus critique pour permettre la miniaturisation. La technique de lithographie qui permet la production en masse est la lithographie optique par projection. Néanmoins cette technologie approche de ses limites en résolution et l'industrie cherche de nouvelles techniques pour continuer à réduire la taille des composants. Les candidats sont l'écriture en plusieurs passes, la lithographie EUV, l'écriture directe, la nano-impression ou l'auto-organisation dirigée. Même si ces alternatives reposent sur des principes très différents, chacune a en commun l'utilisation de la lithographie électronique à un moment ou à un autre de leur réalisation. La lithographie électronique est sujette à des phénomènes spécifiques qui impactent la résolution finale, tels la diffusion des électrons, le « fogging », la diffusion d'acide, la CMP etc… La solution choisie par l'industrie pour tenir compte de tous ces phénomènes est de les prévoir puis de les compenser. Cette correction nécessite de les prédire à l'aide de modélisation, la précision de ces modèles décrivant les procédés étant primordiale. Dans cette thèse, les concepts de base permettant de développer un modèle sont présentés. L'évaluation de la qualité des données, la méthodologie de choix d'un modèle ainsi que la validation de ce model sont introduites. De plus, les concepts d'analyse de sensibilité locale et globale seront définis. L'état de l'art des stratégies utilisées ou envisagées pour les procédés lithographiques actuels ou futurs sont énoncés, chacune des principales étapes lithographiques étant détaillée. Les modèles tenant compte de la physique et de la chimie impactant sur la résolution après écriture par e-beam sont étudiés. De plus, les modèles compacts permettant de prédire les résultats obtenus par e-beam seront détaillés, pour finalement décrire les limitations des stratégies actuelles. De nouveaux modèles compactes sont proposés en introduisant de nouvelles familles de fonctions telles que les fonctions Gamma ou les fonctions de Voigt. De plus, l'utilisation des fonctions d'interpolations de type Spline sont également proposés. Un modèle résine d'utilisation souple a également été développé pour tenir compte de la plupart des comportements expérimentaux observés en évaluant les dimensions de motifs d'un dessin en utilisant des métriques appropriés. Les résultats obtenus en utilisant de telles méthodes montrent une amélioration de la précision de la modélisation, notamment en ce qui concerne les motifs critiques. D'autres modèles spécifiques permettant de décrire les effets d'extrême longue portée ou permettant de compenser les déviations entre deux procédés sont également décrits dans ce travail. Le choix du jeu de motifs de calibration est critique pour permettre à l'algorithme de calibration d'obtenir des valeurs robustes des paramètres du modèle. Plusieurs stratégies utilisées dans la littérature sont brièvement décrites avant l'introduction d'une technique qui utilise l'analyse de sensibilité globale basée sur la variance afin de sélectionner les types de géométries optimales pour la calibration. Une stratégie permettant la sélection de ces motifs de calibration est détaillée. L'étude de l'impact du procédé et des incertitudes de mesures issue de la métrologie est également abordée, ce qui permet d'énoncer les limites à attendre du modèle sachant que les mesures peuvent être imprécises. Finalement, des techniques permettant de s'assurer de la qualité d'un modèle sont détaillées, telle l'utilisation de la validation croisée. La pertinence de ces techniques est démontrée pour quelques cas réel. / Since the development of the first integrated circuit, the number of components fabricated in a chip continued to grow while the dimensions of each component continued to be reduced. For each new technology node proposed, the fabrication process had to cope with the increasing complexity of its scaling down. The lithography step is one of the most critical for miniaturization due to the tightened requirements in both precision and accuracy of the pattern dimension printed into the wafer. Current mass production lithography technique is optical lithography. This technology is facing its resolution limits and the industry is looking for new approaches, such as Multi-patterning (MP), EUV lithography, Direct Write (DW), Nano-imprint or Direct Self-Assembly (DSA). Although these alternatives present significant differences among each other, they all present something in common: they rely on e-beam writers at some point of their flow. E-beam based lithography is subject to phenomena that impact resolution such as are electron scattering, fogging, acid diffusion, CMP loading, etc. The solution the industry adopted to address these effects is to predict and compensate for them. This correction requires predicting the effects, which is achieved through modeling. Hence the importance of developing accurate models for e-beam process. In this thesis, the basic concepts involving modeling are presented. Topics such as data quality, model selection and model validation are introduced as tools for modeling of e-beam lithography. Moreover, the concepts of local and global sensitivity analysis were also presented. Different strategies of global sensitivity analysis were presented and discussed as well as one of the main aspects in its evaluation, which is the space sampling approach. State-of-the-art strategies for todays and future lithography processes were presented and each of their main steps were described. First Principle models that explain the physics and chemistry of the most influential steps in the process resolution were also discussed. Moreover, general Compact models for predicting the results from e-beam lithography were also presented. Finally, some of the limitations of the current approach were described. New compact models described as Point-Spread-Function (PSF) are proposed based on new distributions, such as Gamma and Voigt. Besides, a technique using Splines for describing a PSF is also proposed. Moreover, a flexible resist model able to integrate most of the observed behavior was also proposed, based on evaluating any pattern on the layout using metrics. Results using such method further improved the any of the PSF distribution approach on the critical features that were limiting the future technology nodes. Other specific models and strategies for describing and compensating for extreme-long-range effects and for matching two different fabrication processes are also proposed and described in this work. The calibration layout is a key factor for providing the calibration algorithm with the experimental data necessary to determine the values of each of the parameters of the model. Several strategies from the literature were briefly described before introducing one of the main propositions of this thesis, which is employing variance-based global sensitivity analysis to determine which patterns are more suitable to be used for calibration. A complete flow for selecting patterns for a calibration layout was presented. A study regarding the impact of process and metrology variability over the calibration result was presented, indicating the limits one may expect from the generated model according to the quality of the data used. Finally, techniques for assuring the quality of a model such as cross-validation were also presented and demonstrated in some real-life situations.
180

Examining the Roles of Early Proximity, Degree of Genetic Relatedness, and Disgust in Explaining Father-Daughter and Brother-Sister Incest

Pullman, Lesleigh E. 07 December 2018 (has links)
The goal of this dissertation was to evaluate proximate mechanisms that facilitate incest avoidance, and elucidate under what circumstances these mechanisms may fail, integrating insights from the fields of forensic and evolutionary psychology. To set the stage, Study 1 was a meta-analysis that examined differences between biological and sociolegal incest offenders on two major risk dimensions (antisociality and atypical interests). While sociolegal incest offenders were more problematic on some indicators of antisociality, these groups did not differ in atypical sexual interests. These findings suggest that current models of child sexual abuse may not be sufficient to fully explain incest offending. Studies 2 and 3 examined the viability of the Westermarck hypothesis (1891/1921) - that early physical proximity leads to incest avoidance - and the mediating role of disgust in father-daughter (Study 2) and brother-sister (Study 3) relationships. The primary hypothesis for these studies was that disgust toward incest would mediate the relationship between physical proximity and incest propensity or behaviour. The results of Study 2 did not support the Westermarck hypothesis among fathers. While physical proximity may not activate incest avoidance in fathers, disgust toward incest may still be a proximate mechanism. The results of Study 3 were consistent with the Westermarck hypothesis and the mediating role of disgust as an incest avoidance mechanism among siblings, and also suggest that moderators, such as sexual behaviour that could result in offspring, could influence the strength of this mechanism. These findings suggest that mechanisms responsible for incest avoidance may be different for fathers and siblings.

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