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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.
11

Desenvolvimento de sensores eletroquímicos e colorimétricos para aplicações em amostras de interesse forense / Development of electrochemical and colorimetric sensors for application in forensic interest samples

Araujo, William Reis de 07 June 2016 (has links)
Esta tese apresenta os estudos e esforços visando ao desenvolvimento de sensores químicos para aplicações diversas na área forense. Foram desenvolvidos métodos eletroanalíticos para detecção e quantificação de alguns compostos comumente encontrados na adulteração de amostras de drogas de abuso (procaína, fenacetina, aminopirina, paracetamol, levamisol), além da cocaína e estudos fundamentais sobre o comportamento eletroquímico desses compostos. Empregaram-se também métodos eletroquímicos para quantificação de compostos tóxicos e perigosos como explosivos (ácido pícrico) e melamina por exemplo. Os trabalhos utilizando sensores eletroquímicos contemplam modificações eletroquímicas das superfícies eletródicas, utilização de sensores com polímeros molecularmentes impressos (MIP) e eletrodos descartáveis em papel utilizando diferentes técnicas voltamétricas e amperométricas, eletrodo disco rotatório (EDR) e microbalança de cristal de quartzo. Além da fabricação de dispositivos analíticos descartáveis em papel empregando detecção eletroquímica utilizou-se também a detecção colorimétrica para quantificação de alguns dos principais adulterantes de amostras de apreensão de cocaína, como procaína e fenacetina, bem como análises e discriminações de compostos explosivos (peroxi e nitro compostos) nessas plataformas portáteis e de baixo custo. Os métodos foram sempre desenvolvidos visando característicos como: facilidade, praticidade, baixo custo e portabilidade para análises diretamente no local de medida com mínima infraestrutura laboratorial. Por fim, são apresentados alguns estudos realizados durante estágio de pesquisa no exterior (Universidade da Califórnia - San Diego (UCSD)) na área de Wearable Sensors, em que foram desenvolvidos métodos para análises de micronutrientes no suor (zinco) e um metabólito (ácido úrico) na saliva usando sensores aplicados diretamente no corpo humano. / This thesis shows studies and efforts to the development of chemical sensors for different applications in the forensic field. Electroanalytical methods were developed for detection and quantification of some compounds (procaine, phenacetin, aminopyrine, acetaminophen, levamisole) commonly found in the drug of abuse adulteration process and cocaine, as well as, fundamental studies about the electrochemical behavior of these compounds. It was also employed electrochemical methods for quantification of hazardous compounds such as explosives (picric acid) and melamine. Analytical methods with electrochemical sensors included electrochemical modification of electrodic surfaces, molecularly imprinted polymers (MIP), and paper disposable electrochemical devices using different voltammetric and amperometric techniques, rotating disc electrode (RDE) and quartz crystal microbalance. In addition to the fabrication of paper disposable analytical devices with electrochemical detection, it was also used the colorimetric detection to quantify some of the major adulterants in cocaine seizure samples, such as procaine and phenacetin, as well as analysis and discrimination of explosive compounds (peroxy and nitro explosives) in these low cost portable platforms. All proposed methods were always developed aming at theses characteristics: ease, convenience, low cost and portability for analysis directly at the measurement site with minimal laboratory infrastructure. Finally, we presented some studies conducted during research internship abroad (University of California - San Diego (UCSD)) in the area of Wearable Sensors, which have been developed methods for micronutrient analysis in sweat (Zn) and a metabolite (Uric Acid) in saliva using sensors applied directly to the human body
12

Desenvolvimento de sensores eletroquímicos e colorimétricos para aplicações em amostras de interesse forense / Development of electrochemical and colorimetric sensors for application in forensic interest samples

William Reis de Araujo 07 June 2016 (has links)
Esta tese apresenta os estudos e esforços visando ao desenvolvimento de sensores químicos para aplicações diversas na área forense. Foram desenvolvidos métodos eletroanalíticos para detecção e quantificação de alguns compostos comumente encontrados na adulteração de amostras de drogas de abuso (procaína, fenacetina, aminopirina, paracetamol, levamisol), além da cocaína e estudos fundamentais sobre o comportamento eletroquímico desses compostos. Empregaram-se também métodos eletroquímicos para quantificação de compostos tóxicos e perigosos como explosivos (ácido pícrico) e melamina por exemplo. Os trabalhos utilizando sensores eletroquímicos contemplam modificações eletroquímicas das superfícies eletródicas, utilização de sensores com polímeros molecularmentes impressos (MIP) e eletrodos descartáveis em papel utilizando diferentes técnicas voltamétricas e amperométricas, eletrodo disco rotatório (EDR) e microbalança de cristal de quartzo. Além da fabricação de dispositivos analíticos descartáveis em papel empregando detecção eletroquímica utilizou-se também a detecção colorimétrica para quantificação de alguns dos principais adulterantes de amostras de apreensão de cocaína, como procaína e fenacetina, bem como análises e discriminações de compostos explosivos (peroxi e nitro compostos) nessas plataformas portáteis e de baixo custo. Os métodos foram sempre desenvolvidos visando característicos como: facilidade, praticidade, baixo custo e portabilidade para análises diretamente no local de medida com mínima infraestrutura laboratorial. Por fim, são apresentados alguns estudos realizados durante estágio de pesquisa no exterior (Universidade da Califórnia - San Diego (UCSD)) na área de Wearable Sensors, em que foram desenvolvidos métodos para análises de micronutrientes no suor (zinco) e um metabólito (ácido úrico) na saliva usando sensores aplicados diretamente no corpo humano. / This thesis shows studies and efforts to the development of chemical sensors for different applications in the forensic field. Electroanalytical methods were developed for detection and quantification of some compounds (procaine, phenacetin, aminopyrine, acetaminophen, levamisole) commonly found in the drug of abuse adulteration process and cocaine, as well as, fundamental studies about the electrochemical behavior of these compounds. It was also employed electrochemical methods for quantification of hazardous compounds such as explosives (picric acid) and melamine. Analytical methods with electrochemical sensors included electrochemical modification of electrodic surfaces, molecularly imprinted polymers (MIP), and paper disposable electrochemical devices using different voltammetric and amperometric techniques, rotating disc electrode (RDE) and quartz crystal microbalance. In addition to the fabrication of paper disposable analytical devices with electrochemical detection, it was also used the colorimetric detection to quantify some of the major adulterants in cocaine seizure samples, such as procaine and phenacetin, as well as analysis and discrimination of explosive compounds (peroxy and nitro explosives) in these low cost portable platforms. All proposed methods were always developed aming at theses characteristics: ease, convenience, low cost and portability for analysis directly at the measurement site with minimal laboratory infrastructure. Finally, we presented some studies conducted during research internship abroad (University of California - San Diego (UCSD)) in the area of Wearable Sensors, which have been developed methods for micronutrient analysis in sweat (Zn) and a metabolite (Uric Acid) in saliva using sensors applied directly to the human body
13

Towards a Unilateral Sensor Architecture for Detecting Person-to-Person Contacts

Amara, Pavan Kumar 12 1900 (has links)
The contact patterns among individuals can significantly affect the progress of an infectious outbreak within a population. Gathering data about these interaction and mixing patterns is essential to assess computational modeling of infectious diseases. Various self-report approaches have been designed in different studies to collect data about contact rates and patterns. Recent advances in sensing technology provide researchers with a bilateral automated data collection devices to facilitate contact gathering overcoming the disadvantages of previous approaches. In this study, a novel unilateral wearable sensing architecture has been proposed that overcome the limitations of the bi-lateral sensing. Our unilateral wearable sensing system gather contact data using hybrid sensor arrays embedded in wearable shirt. A smartphone application has been used to transfer the collected sensors data to the cloud and apply deep learning model to estimate the number of human contacts and the results are stored in the cloud database. The deep learning model has been developed on the hand labelled data over multiple experiments. This model has been tested and evaluated, and these results were reported in the study. Sensitivity analysis has been performed to choose the most suitable image resolution and format for the model to estimate contacts and to analyze the model's consumption of computer resources.
14

Investigation of Photodetector Optimization in Reducing Power Consumption by a Noninvasive Pulse Oximeter Sensor

Pujary, Chirag Jayakar 16 January 2004 (has links)
Noninvasive pulse oximetry represents an area of potential interest to the army, because it could provide cost-effective, safe, fast and real-time physiological assessment in a combat injured soldier. Consequently, there is a need to develop a reliable, battery-powered, wearable pulse oximeter to acquire and process photoplethysmographic (PPG) signals using an optimized sensor configuration. A key requirement in the optimal design of a wearable wireless pulse oximeter is low power management without compromising signal quality. This research investigated the advantage gained by increasing the area of the photodetector and decreasing the light emitting diode (LED) driving currents to reduce the overall power requirement of a reflectance mode pulse oximeter sensor. In vitro and preliminary in vivo experiments were conducted to evaluate a multiple photodetector reflectance sensor setup to simulate a varying detection area. It was concluded that a reflection pulse oximeter sensor employing a large area photodetector is preferred over a similar transmission type sensor for extending the battery life of a wireless pulse oximeter intended for future telemedicine applications.
15

Assessing the validity of the zero-velocity update method for sprinting speeds

Pla, Gerard 01 September 2022 (has links)
INTRODUCTION: The zero-velocity update (ZUPT) method has become a popular approach to estimate foot kinematics from foot worn inertial measurement units (IMUs) for walking and running. However, it remains unknown how accurate the ZUPT method is for track sprinting speeds when using sensors with characteristics (i.e., higher ranges and sampling rates) better suited for sprinting. METHODS: 18 participants performed 70-meter track sprints while wearing a Blue Trident IMeasureU IMU. Two cameras, at 20 and 70 meters from the start, were placed to validate the ZUPT method on a stride-by-stride and on a cumulative distance basis. The validity of the method was assessed on: (1) A single stride attained at the end of the maximal speed phase, i.e., at 70m; (2) On a cumulative distance basis for the maximal speed phase from 20 to 70 meter; and (3) On total distance traveled for a 70-meter track sprint. RESULTS: Individual stride and cumulative distance errors remained within -8 to 3% and -4 to 2%, respectively. CONCLUSION: The results of this study demonstrate the ZUPT method is capable of yielding accurate estimates of stride length and cumulative distance traveled for sprinting speeds.
16

Signal Quality Assessment of Photoplethysmogram for Heart Rate Estimation

Uyanik Civek, Ceren January 2020 (has links)
No description available.
17

Improving Pain Management in Patients with Sickle Cell Disease Using Machine Learning Techniques

Yang, Fan 31 August 2020 (has links)
No description available.
18

Longitudinal monitoring of biomechanical and psychological stress in collegiate female basketball athletes: Implications to sports performance and injury susceptibility

Keogh, Joshua A.J. January 2023 (has links)
The unprecedented growth in participation in collegiate athletics has been accompanied by an increase in injury burden. The complex and multifactorial nature of sports injuries highlights the importance of monitoring athletes prospectively using a novel and holistic biopsychosocial approach, as opposed to contemporary practices that silo these facets of health. Data collected over two competitive, basketball seasons were used in a principal component analysis (PCA) model with the following objectives: i) Determine if on-court, sensor-derived and force-plate-derived countermovement jump (CMJ) biomechanics were correlated, ii) determine the reliability of the biomechanical principal components (PCs) and psychological state metrics (e.g., self-reported pain, etc.) across five preseason weeks, iii) investigate whether biomechanical PCs were correlated with psychological state across a season, and iv) explore whether subject-specific meaningful fluctuations could be detected using minimum detectable change statistics. Weekly CMJ (force plates) and on-court data (inertial measurement units), as well as psychological state (questionnaire) data were collected on the women’s basketball team at McMaster University for two seasons. It was found that on-court and CMJ biomechanics were correlated both between and within systems (r = |0.10, 0.94|; p < 0.05), suggesting that PCA would be an effective method to summarize data. The derived PCs displayed excellent reliability (ICC > 0.9), while psychological state metrics displayed moderate-to-good reliability (ICC = 0.71 – 0.89). While many relationships (n = 27) were identified between biomechanical PCs and psychological state metrics, no overarching associations were identified at the group level. However, subject-specific relationships were identified in case-studies, highlighting the potential utility of “red-flagging” meaningful fluctuations from normative biomechanical and psychological patterns. Overall, this work demonstrates the potential of advanced analytical modeling to characterize components of student-athlete performance, health, and well-being, and the need for more tailored and patient-centered athletic monitoring practices. / Thesis / Master of Science (MSc)
19

ENHANCE ROBOTIC-ASSISTED SURGERY WITH A SENSING-BASED ADAPTIVE SYSTEM

Jing Yang (16361256) 15 June 2023 (has links)
<p>The advancement of robotic-assisted surgery (RAS) has revolutionized the field by enabling surgeons to perform intricate procedures with enhanced precision, improved depth perception, and more precise control. Despite these advancements, current RAS systems still rely on teleoperation, where surgeons control the robots remotely. The complexity of the master-slave control mechanism, along with the technical challenges involved, can impose significant mental workloads on surgeons. As excessive mental workload (MWL) can adversely affect performance and increase the likelihood of errors, addressing operator mental overload has become crucial for successful operation in RAS. To tackle this problem, there has been increased interest in developing robots that can provide operators with varying levels of assistance based on their MWL (i.e., adaptive system) during task execution. However, the research in this area is notably limited, primarily due to two key factors: the absence of a real-time MWL assessment framework and the lack of effective intervention strategies to mitigate MWL in RAS.</p> <p>This Ph.D. dissertation aims to fill these gaps by designing the adaptive system in RAS and exploring its impact on surgical task performance. The dissertation comprises three studies. The first study demonstrated the feasibility of the adaptive system in RAS by introducing an MWL-triggered semi-autonomous suction tool as a proof-of-concept. Building upon the insights gained from the first study, the second study focused on enhancing the adaptive system's adaptability to more complex RAS tasks. In particular, the second study proposed a task-independent MWL model that had potential to be applied to various RAS tasks. Additionally, more intelligent interventions were investigated. Furthermore, the third study aimed to investigate the benefits of adaptive system in RAS training by introducing a personalized and adaptive training program based on human MWL profile. The findings of this dissertation revealed evidence supporting the effectiveness of the adaptive system in moderating subjects’ MWL, and its potential in enhancing task performance in RAS. This dissertation highlights the potential of incorporating adaptive systems into future RAS platforms, so that to provide valuable support and assistance to surgeons during critical moments and facilitate surgical training by identifying and addressing the specific needs of surgeons.</p>
20

Wearable Sensors Outperform Behavioral Coding as Valid Marker of Childhood Anxiety and Depression

McGinnis, Ellen, McGinnis, Ryan, Hruschak, Jessica, Bilek, Emily, Ip, Ka, Morelen, Diana, Lawler, Jamie, Fitzgerald, Kate, Rosenblum, Katherine, Musik, Maria 25 April 2018 (has links) (PDF)
There is a significant need to develop objective measures for identifying children under the age of 8 who have anxiety and depression. If left untreated, early internalizing symptoms can lead to adolescent and adult internalizing disorders as well as comorbidity which can yield significant health problems later in life including increased risk for suicide. To this end, we propose the use of an instrumented fear induction task for identifying children with internalizing disorders, and demonstrate its efficacy in a sample of 63 children between the ages of 3 and 7. In so doing, we extract objective measures that capture the full six degree-of-freedom movement of a child using data from a belt-worn inertial measurement unit (IMU) and relate them to behavioral fear codes, parent-reported child symptoms and clinician-rated child internalizing diagnoses. We find that IMU motion data, but not behavioral codes, are associated with parent-reported child symptoms and clinician-reported child internalizing diagnosis in this sample. These results demonstrate that IMU motion data are sensitive to behaviors indicative of child psychopathology. Moreover, the proposed IMU-based approach has increased feasibility of collection and processing compared to behavioral codes, and therefore should be explored further in future studies.

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