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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.
819881

Control of Self-Organizing and Geometric Formations

Pruner, Elisha 24 January 2014 (has links)
Multi-vehicle systems offer many advantages in engineering applications such as increased efficiency and robustness. However, the disadvantage of multi-vehicle systems is that they require a high level of organization and coordination in order to successfully complete a task. Formation control is a field of engineering that addresses this issue, and provides coordination schemes to successfully implement multi-vehicle systems. Two approaches to group coordination were proposed in this work: geometric and self-organizing formations. A geometric reconfiguring formation was developed using the leader-follower method, and the self-organizing formation was developed using the velocity potential equations from fluid flow theory. Both formation controllers were first tested in simulation in MATLAB, and then implemented on the X80 mobile robot units. Various experiments were conducted to test the formations under difficult obstacle scenarios. The robots successfully navigated through the obstacles as a coordinated as a team using the self-organizing and geometric formation control approaches.
819882

Immune Dysfunction Associated with Hemodialysis Modalities

Slatculescu, Andreea M. 24 January 2014 (has links)
Infection is a leading cause of death in hemodialysis patients, partly due to dysfunctional immunity. Frequent dialysis therapy improves patient outcomes and quality of life. We hypothesize that extended home hemodialysis (EHHD) also improves immune function compared to conventional in-hospital hemodialysis (CHD); therefore, we designed a prospective matching-cohort clinical study to assess serum inflammatory markers and the functional capacity of monocyte-derived dendritic cells (MDDCs) and T-lymphocytes. Serum CRP was decreased in EHHD patients suggesting that extended dialysis may decrease inflammatory solute/cytokine levels. Compared to controls, MDDCs from hemodialysis patients had similar endocytic capacity, expression of co-stimulatory molecules, and T-cell activation capacity. However, CHD was associated with the highest expression of CD83 and CD40. Activated T-cells in CHD patients also produced significantly more immunosuppressive IL-10 compared to EHHD patients and controls. Therefore, EHHD may improve immune function by decreasing inflammation, MDDC pre-activation, and synthesis of immunosuppressive cytokines.
819883

CAHR: A Contextually Adaptive Rehabilitation Framework for In-Home Training

Karime, Ali 24 January 2014 (has links)
Home-based rehabilitation has evolved in recent years as a cost-effective and convenient alternative to traditional clinical rehabilitation. Researchers have developed various types of sensors-based rehabilitation systems that incorporate Virtual Reality games aimed to offer the patient an entertaining and beneficial training experience from the comfort of home. This has consequently created the need to design reliable assessment and adaptation mechanisms that are able to measure and analyze the patient's performance and condition, and to accordingly make proper adjustments that conform to the abilities of the patient during the training. In this dissertation, we introduce our context-based adaptive home-based rehabilitation framework (CAHR) that offers the patients a rehabilitation environment that can adapt based on their physical, physiological, and psychological context, while taking into consideration the environmental conditions that may hinder their progress. CAHR is a generic framework that can be implemented to fit any of the upper or lower extremity rehabilitation. However, in this dissertation, we base our modeling and analysis mainly on the wrist. In CAHR, the physical condition of the patient is assessed by a fuzzy logic-based mechanism that uses the various kinematics captured during the training to provide a quantified value which reflects the Quality of Physical Performance of the patient. The rehabilitation task adaptation is achieved based on a special algorithm that defines how the physical training, psychophysiological responses, and environmental conditions must be manipulated in order to match the desired performance target parameters set by the therapist. The simulation results have shown that the proposed adaptation engine can properly adjust the rehabilitation environment based on different simulated performance behavior that might be produced by a patient. In addition, training with a special game that has been designed based on the developed framework has shown improvement in the physical capabilities of two patients suffering from upper extremity impairments.
819884

Multilingual Children's Mathematical Reasoning

Assaf, Fatima 24 January 2014 (has links)
This research adopts a sociocultural framework (Vygotsky, 1978) to investigate how multilingual children express their mathematical reasoning during collaborative problem solving. The topic is important because North America is becoming increasingly multicultural, and according to mathematics teachers this has complicated the challenges of teaching and learning mathematics. Many educators assume that children should be competent in the language of instruction before they engage with mathematical content (Civil, 2008; Gorgorió & Planas, 2001). A review of recent research in this area challenges the idea that multilingual students need to have mastered the official language of instruction prior to learning mathematics (Barwell, 2005; Civil, 2008; Moschkovich, 2007). These researchers demonstrate that the knowledge of the language of instruction is only one aspect of becoming competent in mathematics. My research was designed to build on the findings of the current research on multilingual children’s reasoning in order to more fully understand how multilingual children express their mathematical understanding and reasoning. For this study, two multilingual families, each with 3 children between the ages of 8 and 12, participated in a mathematical problem-solving activity. Findings show the children’s mathematical reasoning was evidence-based drawing on mathematical knowledge and world knowledge.
819885

Seismic Risk Assessment of Unreinforced Masonry Buildings Using Fuzzy Based Techniques for the Regional Seismic Risk Assessment of Ottawa, Ontario

El Sabbagh, Amid 28 January 2014 (has links)
Unreinforced masonry construction is considered to be the most vulnerable forms of construction as demonstrated through recent earthquakes. In Canada, many densely populated cities such as (Vancouver, Montreal and Ottawa) have large inventories of seismically vulnerable masonry structures. Although measures have been taken to rehabilitate and increase the seismic resistance of important and historic structures, many existing unreinforced masonry structures have not been retrofitted and remain at risk in the event of a large magnitude earthquake. There is therefore a need to identify buildings at risk and develop tools for assessing the seismic vulnerability of existing unreinforced masonry structures in Canada. This thesis presents results from an ongoing research program which forms part of a multi-disciplinary effort between the University of Ottawa’s Hazard Mitigation and Disaster Management Research Centre and the Geological Survey of Canada (NRCAN) to assess the seismic vulnerability of buildings in dense urban areas such as Ottawa, Ontario. A risk-based seismic assessment tool (CanRisk) has been developed to assess the seismic vulnerability of existing unreinforced masonry and reinforced concrete structures. The seismic risk assessment tool exploits the use of fuzzy logic, a soft computing technique, to capture the vagueness and uncertainty within the evaluation of the performance of a given building. In order to conduct seismic risk assessments, a general building inventory and its spatial distribution and variability is required for earthquake loss estimations. The Urban Rapid Assessment Tool (Urban RAT) is designed for the rapid collection of building data in urban centres. This Geographic Information System (GIS) based assessment tool allows for intense data collection and revolutionizes the traditional sidewalk survey approach for collecting building data. The application of CanRisk and the Urban RAT tool to the City of Ottawa is discussed in the following thesis. Data collection of over 13,000 buildings has been obtained including the seismic risk assessment of 1,465 unreinforced masonry buildings. A case study of selected URM buildings located in the City of Ottawa was conducted using CanRisk. Data obtained from the 2011 Christchurch Earthquake in New Zealand was utilized for verification of the tool.
819886

Electrical Bioimpedance as a Detection Tool for Internal Hemorrhaging and Blood Aggregation

Morse, John 28 January 2014 (has links)
Electrical bioimpedance was used to detect local volume and aggregation changes in blood. This was done with two separate experimentation processes to improve upon current research methods. Abdominal internal hemorrhaging is bleeding and pooling of blood within the abdominal cavity which can put the welfare of the patient at risk and may cause organ failure. Electrical bioimpedance is the response of biological tissue to applied electrical current. In cooperation with Bioparhom, electrical bioimpedance was used as a detection device for abdominal internal hemorrhaging. It is hypothesized that electrical bioimpedance could be a non-invasive and cost effective avenue for the detection of internal bleeding. In this study we investigate the use of electrical bioimpedance with a custom 8x8 needle electrode array, for detecting and locating the blood pooling due to a drop in resistivity in a rat using a Z-Metrix (function generator by Bioparhom). 5 and 95 kHz signals were inputted into a dead rat experiencing internal bleeding of porcine blood at a rate of 3.33 ml/min to 10 ml. For 8 rats, the 5 kHz frequency was found to be more sensitive to internal blood pooling. Red blood cell aggregation is a physiological process where red blood cells form reversible aggregates. RBC aggregation is an important indicator for physicians for the health of the circulatory system. Utilizing electrical bioimpedance, it is hypothesized that a reactance change as a result of blood aggregation will be detected. As well, a method is developed using impedance spectroscopy to determine s frequency which exhibits the highest reactance change during blood aggregation. This sensitive frequency, found to be 304 kHz, is compared to a frequency used by previous studies (100 kHz) to validate its. Using the Z-Metrix (function generator by Bioparhom) with a custom 4 electrode configuration, 2 ml of porcine blood mixed with 2 mg/ml of EDTA is tested for 2 minutes at a single frequency. The 304 kHz is found to be the most sensitive of the frequencies tested to reactance changes during aggregation. Results found for blood samples give an average AIc of 27.32 ± 11.44, which is within the physiological range for porcine blood of 3-30. It is seen that the 304 kHz has a higher precision than the 100 kHz frequency, but the AIc is within the same magnitude. As a result, 304 kHz is found to be a more favorable frequency than the previously published 100 kHz for the trials performed based on precision of the results and the sensitivity of the reactance change to blood aggregation.
819887

Whole-Body Cooling Following Exercise-Induced Hyperthermia: Biophysical Considerations

Friesen, Brian J. 28 January 2014 (has links)
This thesis examined the effect of differences in body surface area-to-lean body mass ratio (AD/LBM) on core temperature cooling rates during cold water immersion (2°C, CWI) and temperate water immersion (26°C, TWI) following exercise-induced hyperthermia (end-exercise rectal temperature of 40°C). Individuals with a High AD/LBM (315 cm2/kg) had a ~1.7-fold greater overall rectal cooling rate relative to those with Low AD/LBM (275 cm2/kg) during both CWI and TWI. Further, overall rectal cooling rates during CWI were ~2.7-fold greater than during TWI for both the High and Low AD/LBM groups. Study findings show that AD/LBM must be considered when determining the duration of the immersion period. However, CWI provides the most effective cooling treatment for EHS patients irrespective of physical differences between individuals.
819888

Computational Investigation of Intense Short-Wavelength Laser Interaction with Rare Gas Clusters

Bigaouette, Nicolas 28 January 2014 (has links)
Clusters of atoms have remarkable optical properties that were exploited since the antiquity. It was only during the late 20th century though that their production was better controlled and opened the door to a better understanding of matter. Lasers are the tool of choice to study these nanoscopic objects so scientists have been blowing clusters with high intensities and short duration laser pulses to gain insights on the dynamics at the nanoscale. Clusters of atoms are an excellent first step in the study of bio-molecules imaging. New advancements in laser technology in the shape of Free Electron Lasers (FEL) made shorter and shorter wavelengths accessible from the infrared (IR) to the vacuum and extreme ultra-violet (VUV and XUV) to even X-rays. Experiments in these short wavelengths regimes revealed surprisingly high energy absorption that are yet to be fully explained. This thesis tries to increase the global knowledge of clusters of rare-gas atoms interacting with short duration and high intensity lasers in the VUV and XUV regime. Theoretical and numerical tools were developed and a novel model of energy transfer based on excited states will be presented. The first part describes the current knowledge of laser-cluster interaction in the short wavelength regime followed by the description of the new model. In the second part of the thesis the different tools and implementations used throughout this work are presented. Third, a series of journal articles (of which four are published and one to be submitted) are included where our models and tools were successfully used to explain experimental results.
819889

The Immune Response in Parkinson's Disease

Lira, Arman 28 January 2014 (has links)
Microglia activity has been detected in Parkinson’s disease (PD) post-mortem brains and experimental animal models; however the precise interplay between microglia and dopamine neurons of the SNpc is not well understood. In the blood plasma of PD patients, our laboratory found elevated levels of interferon-gamma (IFN-γ), a proinflammatory cytokine and potent activator of microglia. Given this, we sought to untangle the immune responses relevant to PD in mice, examining IFN-γ’s involvement and signaling mechanism using an inflammatory co-culture model of microglia and midbrain neurons treated with rotenone. By means of RT-PCR, we discovered IFN-γ mRNA transcripts are produced by microglia, and this expression increases upon exposure to rotenone. We delineated IFN-γ’s signaling mechanism in co-cultures using different IFN-γ receptor deficient cells, and showed it engages receptors in an autocrine (not paracrine) manner to further microgliosis and dopamine cell loss. After exploring the innate immune response in a model of PD, we subsequently shifted focus to an in vivo system to better investigate any involvement of the delayed humoral arm of the adaptive immune system. Needing a time appropriate death paradigm, we developed a protracted low dose regimen of MPTP, which elicits dopaminergic cell death after 2 weeks of treatment. Subjected to this paradigm, Rag 2 mutant mice (deficient in both T and B cells) exhibit resistance to dopamine cell loss, microglia activation and motor impairments. Further evidence in support of immune involvement came with the resensitization of Rag2 mice to MPTP after reconstitution with WT splenocytes. Additionally, mice deficient in Fcγ receptors exhibited neuroprotection in our protracted degeneration model. Taken together, these data indicate the innate and humoral arm can modulate the microglial response to dopaminergic degeneration and may participate in Parkinson's disease.
819890

Emotionally Focused Therapy for Japanese Couples: Development and Empirical Investigation of a Culturally-Sensitive EFT Model

Hattori, Kyoko 28 January 2014 (has links)
In this doctoral thesis, a culturally-sensitive couple therapy model was developed and empirically investigated. In particular, a Western-based couple therapy, Emotionally-Focused Couple Therapy (EFT), was modified to enhance the cultural relevancy of this model to the Japanese population. An extensive literature review was conducted to examine the status of psychotherapy and couple research in Japan, and cultural differences between Western and Japanese couples, with a particular emphasis on important couple variables, including emotional expression, communication, conflict resolution, and attachment. Study objectives included an empirical investigation into cultural differences on key relationship variables of trust, attachment, communication, and conflict resolution, and the use of these findings to guide adaptations of EFT to enhance cultural relevance, and an exploration of the adapted EFT model with three Japanese couples. This study is significant in that it is the first to empirically evaluate the cross-cultural validity of EFT. This dissertation consists of two studies that have been combined in one article for the purpose of publishing the document in a Japanese journal. Both studies were combined in one article for various reasons. First, study one findings are integral to the development of the culturally-sensitive EFT model that is empirically investigated in the second study. Second, the article included in this dissertation will be translated and prepared for publication in a Japanese journal. Including both studies in one article is important given the lack of familiarity in the Japanese research community about key relationship variables, and particularly their applicability to a couple therapy system (i.e., EFT), and their use to measure change in a couple therapy outcome study.

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