Дисертації: "Stress data"

1

Jelinek, Lena. "Memory fragmentation in posttraumatic stress disorder content specific or generalised." Berlin wvb, Wiss. Verl, 2006. http://www.wvberlin.de/data/inhalt/jelinek.html.

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2

Jelinek, Lena. "Memory fragmentation in posttraumatic stress disorder : content specific or generalised /." Berlin : Wvb, Wiss. Verl, 2007. http://www.wvberlin.de/data/inhalt/jelinek.html.

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3

Lindqvist, Anton. "Stress Response Analysis Using Centralised Expression Data." Thesis, Umeå universitet, Institutionen för fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-177326.

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Background: The last two decades have seen several new methods for analysing gene expression data. One such method is pathway analysis in which it’s possible to decipher response patterns between pathways (groups of interacting genes) and external stress factors. A critical issue in pathway analysis is often limited sample sizes resulting in undesirable batch affects. A method for reducing such effects, called Centralization Within Sub-Experiments (CSE), has recently been developed. This method makes it possible to predict pathways using data from experiments with a diversity of external conditions. Aims: We propose a method for identifying stress-responsive pathways predicted using CSE pre-processed expression data. Method: 27 CSE predicted pathways were analysed and tested for stress-responsiveness associated with specific external stress factors. Firstly, we screened the complete gene list for DE genes. Secondly, we analysed the occurrences of DE genes within each pathway and finally, an over-representation analysis was performed with the aim of identifying pathways with significantly larger portions of differently expressed genes categorised as stress-responsive. Results: The analysis resulted in a list of pathways with significantly larger proportions of DE genes. This was only when screened for salt-responsive pathways. We also found that these pathways contained several mitochondrial genes confirmed to be associated with salt stress. Conclusion: The results show great promise in using the method for extracting information regarding the stress responsiveness amongst pathways predicted using CSE-pre-processing expression data.

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4

Weber, Annegret. "Einfluss von Stress und sozialen Faktoren auf die Immunreaktivität sechsjähriger Kinder /." Leipzig : UFZ, 2008. http://www.ufz.de/data/ufzdiss_07_20089040.pdf.

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5

Ollander, Simon. "Wearable Sensor Data Fusion for Human Stress Estimation." Thesis, Linköpings universitet, Reglerteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-122348.

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With the purpose of classifying and modelling stress, different sensors, signal features, machine learning methods, and stress experiments have been compared. Two databases have been studied: the MIT driver stress database and a new experimental database, where three stress tasks have been performed for 9 subjects: the Trier Social Stress Test, the Socially Evaluated Cold Pressor Test and the d2 test, of which the latter is not classically used for generating stress. Support vector machine, naive Bayes, k-nearest neighbor and probabilistic neural network classification techniques were compared, with support vector machines achieving the highest performance in general (99.5 ±0.6 %$on the driver database and 91.4 ± 2.4 % on the experimental database). For both databases, relevant features include the mean of the heart rate and the mean of the galvanic skin response, together with the mean of the absolute derivative of the galvanic skin response signal. A new feature is also introduced with great performance in stress classification for the driver database. Continuous models for estimating stress levels have also been developed, based upon the perceived stress levels given by the subjects during the experiments, where support vector regression is more accurate than linear and variational Bayesian regression.
I syfte att klassificera och modellera stress har olika sensorer, signalegenskaper, maskininlärningsmetoder och stressexperiment jämförts. Två databaser har studerats: MIT:s förarstressdatabas och en ny databas baserad på egna experiment, där stressuppgifter har genomförts av nio försökspersoner: Trier Social Stress Test, Socially Evaluated Cold Pressor Test och d2-testet, av vilka det sistnämnda inte normalt används för att generera stress. Support vector machine-, naive Bayes-, k-nearest neighbour- och probabilistic neural network-algoritmer har jämförts, av vilka support vector machine har uppnått den högsta prestandan i allmänhet (99.5 ± 0.6 % på förardatabasen, 91.4 ± 2.4 % på experimenten). För båda databaserna har signalegenskaper såsom medelvärdet av hjärtrytmen och hudens ledningsförmåga, tillsammans med medelvärdet av beloppet av hudens ledningsförmågas derivata identifierats som relevanta. En ny signalegenskap har också introducerats, med hög prestanda i stressklassificering på förarstressdatabasen. En kontinuerlig modell har också utvecklats, baserad på den upplevda stressnivån angiven av försökspersonerna under experimenten, där support vector regression har uppnått bättre resultat än linjär regression och variational Bayesian regression.

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6

Nytorpe, Piledahl Staffan, and Daniel Dahlberg. "Detektering av stress från biometrisk data i realtid." Thesis, Högskolan i Halmstad, Akademin för informationsteknologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-31248.

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At the time of writing, stress and stress related disease have become the most common reasons for absence in the workplace in Sweden. The purpose of the work presented here is to identify and notify people managing unhealthy levels of stress. Since symptoms of mental stress manifest through functions of the Sympathetic Nervous System (SNS), they are best measured through monitoring of SNS changes and phenomena. In this study, changes in the sympathetic control of heart rate were recorded and analyzed using heart rate variability analysis and a simple runner’s heart rate sensor connected to a smartphone. Mental stress data was collected through stressful video gaming. This was compared to data from non-stressful activities, physical activity and extremely stressful activities such as public speaking events. By using the period between heartbeats and selecting features from the frequency domain, a simple machine learning algorithm could differentiate between the types of data and thus could effectively recognize mental stress. The study resulted in a collection of 100 data points, an algorithm to extract features and an application to continuously collect and classify sequences of heart periods. It also revealed an interesting relationship in the data between different subjects. The fact that continuous stress monitoring can be achieved using minimally intrusive sensors is the greatest benefit of these results, especially when connsidering its potential value in the identification and prevention of stress related disease.

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7

Franaszek, Krzysztof. "Translation-mediated stress responses : mining of ribosome profiling data." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/269473.

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Advances in next-generation sequencing platforms during the past decade have resulted in exponential increases in biological data generation. Besides applications in determining the sequences of genomes and other DNA elements, these platforms have allowed the characterization of cell-wide mRNA pools under different conditions and in different tissues. In 2009, Ingolia and colleagues developed an extension of high-throughput sequencing that provides a snapshot of all cellular mRNA fragments protected by translating ribosomes, dubbed ribosome profiling. This approach allows detection of differential translation activity, annotation of novel protein coding sequences and variants, identification of ribosome pause sites and estimates of de novo protein synthesis. As with other sequencing based methodologies, a major challenge of ribosome profiling has been sorting, filtering and interpreting the gigabytes of data produced during the course of a typical experiment. In this thesis, I developed and applied computational pipelines to interrogate ribosome profiling data in relation to gene expression in several viruses and eukaryotic species, as well as to identify sites of ribosomal pausing and sites of non-canonical translation activity. Specifically, I applied various control analyses for characterizing the quality of profiling data and developed scripts for visualizing genome-based (exon-by-exon) rather than transcript-based ribosome footprint alignments. I also examined the challenge of mapping footprints to repetitive sequences in the genome and propose ways to mitigate the associated problems. I performed differential expression analyses on data from coronavirus-infected murine cells, retrovirus-infected human cells and temperature-stressed Arabidopsis thaliana plants. Dissection of translational responses in Arabidopsis thaliana during heat shock or cold shock revealed several groups of genes that were highly upregulated within 10 minutes of temperature challenge. Analysis of the branches of the unfolded protein and integrated stress responses during coronavirus infection allowed for deconvolution of transcriptional and translational contributions. During the course of these analyses, I identified errors in a recently publicized algorithm for detection of differential translation, and wrote corrections that have now been pulled into the repository for this package. Comparison of the translational kinetics of the dengue virus infection in mosquito and human cell lines revealed host-specific sites of ribosome pausing and RNA accumulation. Analysis of HIV profiling data revealed footprint peaks which were in agreement with previously proposed models of peptide or RNA mediated ribosome stalling. I also developed a simulation to identify transcripts that are prone to generating RPFs with multiple alignments during the read mapping process. Together, the scripts and pipelines developed during the course of this work will serve to expedite future analyses of ribosome profiling data, and the results will inform future studies of several important pathogens and temperature stress in plants.

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8

Zhang, Su Juan. "Automated reflection photoelasticity : digital data acquisition and use." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340144.

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9

Agnér, Christian, and Anneli Blomqvist. "Evaluating Stress through Machine Learning based on Brain Activity Data." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214709.

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More people are experiencing stressrelatedsymptoms, which is not only causing worsenhealth, but also causing economical drawbacks for thesociety, businesses and individuals. The aim of thisproject is to create a tool that evaluates stress frombrain activity data and can help to avoid develop thesymptoms.An EMOTIV Epoch EEG headset is used to recorddata. The stress level is evaluated from the brainactivity data by the parameters, feeling of pleasure(valence) and the mental workload. k-NN machinelearning is utilized to create a valence classificationalgorithm and the theta power density spectrum is usedto determine the workload. Eye movement disturbancesin the recordings are also addressed.Tests with Stroop word color games as stress stimuliare conducted and the project concludes that it ispossible to determine the stress level correctly, onaverage, 17.56% and when allowing one level difference,48.71% .

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10

Vickers, Stephen R. "Examining the Duplication of Flight Test Data Centers." International Foundation for Telemetering, 2011. http://hdl.handle.net/10150/595653.

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ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada
Aircraft flight test data processing began with on site data analysis from the very first aircraft design. This method of analyzing flight data continued from the early 1900's to the present day. Today each new aircraft program builds a separate data center for post flight processing (PFP) to include operations, system administration, and management. Flight Test Engineers (FTE) are relocated from geographical areas to ramp up the manpower needed to analyze the PFP data center products and when the first phase of aircraft design and development is completed the FTE headcount is reduced with the FTE either relocated to another program or the FTE finds other employment. This paper is a condensed form of the research conducted by the author on how the methodology of continuing to build PFP data centers cost the aircraft company millions of dollars in development and millions of dollars on relocation plus relocation stress effects on FTE which can hinder productivity. This method of PFP data center development can be avoided by the consolidation of PFP data centers using present technology.

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11

Stout, Tyler. "Multilevel modeling issues and the measurement of stress is multilevel data." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2979.

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Multilevel datasets are commonly used and increasingly popular in research in the organizational and other social sciences. These models are complex and have many elements beyond those found in more traditional linear models. However, research on how multilevel models perform is lacking. The current paper examined the impact of common factors (average cluster size, cluster size distribution, average number of clusters, strength of the intraclass correlation coefficient, and effect sizes of individual and cluster level variables, and their interaction) in multilevel datasets. Monte Carlo data simulation was used across 6,144 factor-combination conditions. The results of study factors on observed intraclass correlation coefficients, calculated design effect, and empirical design effect are discussed. The results of this study have implications for both researchers in both academic and applied fields. The scale of the simulation variables allow it to be germane to datasets from across the social sciences. However, the nature of data simulation and analysis is such that there are still many elements that can and should be accounted for in future research.

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12

Bracher, Grant Allan. "Detection of nutrient stress in Douglas-fir seedlings using spectroradiometer data." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30961.

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Narrow-band spectral reflectance measurements in the visible and near-infrared region of the spectrum were investigated for the detection of nutrient deficiencies, and estimating the foliar concentrations of nitrogen, phosphorus, sulphur, and total chlorophyll. One-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were treated with 24 nutrient solutions containing nitrogen, phosphorus and sulphur levels ranging from 1 to 400 mg/L. After one growing season, newly matured needles were harvested, spectral reflectance measured from 400 to 1100 nm, and foliar samples analyzed for nutrient and chlorophyll levels. Several nutrient deficiencies were diagnosed. There were no unique changes in spectral reflectance which could be attributed to a specific nutrient deficiency; rather changes in reflectance were non-specific responses influenced by how varying nutrient levels affected total chlorophyll concentration. All deficiencies caused decreases in total chlorophyll, thus demonstrating the value of total chlorophyll as an indicator of nutrient stress. Correlation coefficients were calculated describing the degree of association between foliar nitrogen, phosphorus, sulphur and total chlorophyll, and the following spectral parameters: the wavelength of the red edge, percent spectral reflectance at 554 and 630 nm (red rise), and 15 vegetation indices (VIs). VIs were first determined using combinations of spectral reflectances at 480, 554, 800 nm and the wavelength of the red well (674 nm; called red well VIs), and then recalculated using red rise (called red rise VIs) rather than red well measurements to see if greater correlation with foliar constituents could be obtained. Although the use of red rise measurements in the calculation of VIs 1, 2, 3, 12 and 14 resulted in higher correlation coefficients, differences between coefficients were seldom statistically significant. Red well and red rise VI15 were most correlated with the needle nitrogen content of individual Douglas-fir, red rise VI10 with phosphorus, and spectral reflectance at 554 nm and red well VI15 with total chlorophyll. These parameters proved useful indicators of relative nitrogen, phosphorus and total chlorophyll content. None of the VIs or other spectral parameters followed the same relationship with foliar sulphur for the sulphur, nitrogen and phosphorus treatments; consequently, none were deemed suitable for sulphur estimation.
Forestry, Faculty of
Graduate

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13

Radonovich, David Charles. "Methods of Extrapolating Low Cycle Fatigue Data to High Stress Amplitudes." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3460.

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Modern gas turbine component design applies much effort into prediction and avoidance of fatigue. Advances in the prediction of low-cycle fatigue (LCF) cracks will reduce repair and replacement costs of turbine components. These cracks have the potential to cause component failure. Regression modeling of low-cycle fatigue (LCF)test data is typically restricted for use over the range of the test data. It is often difficult to characterize the plastic strain curve fit constants when the plastic strain is a small fraction of the total strain acquired. This is often the case with high strength, moderate ductility Ni-base superalloys. The intent of this project is to identify the optimal technique for extrapolating LCF test results into stress amplitudes approaching the ultimate strength. The proposed method to accomplish this is by finding an appropriate upper and lower bounds for the cyclic stress-strain and strain-life equations. Techniques investigated include: monotonic test data anchor points, strain-compatibility, and temperature independence of the Coffin-Manson relation. A Ni-base superalloy (IN738 LC) data set with fully reversed fatigue tests at several elevated temperatures with minimal plastic strain relative to the total strain range was used to model several options to represent the upper and lower bounds of material behavior. Several high strain LCF tests were performed with stress amplitudes approaching the ultimate strength. An augmented data set was developed by combining the high strain data with the original data set. The effectiveness of the bounding equations is judged by comparing the bounding equation results with the base data set to a linear regression model using the augmented data set.
M.S.M.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical Engineering MSME

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14

Sha, Wei. "Microarray data analysis methods and their applications to gene expression data analysis for Saccharomyces cerevisiae under oxidative stress." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27840.

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Oxidative stress is a harmful condition in a cell, tissue, or organ, caused by an imbalance between reactive oxygen species or other oxidants and the capacity of antioxidant defense systems to remove them. These oxidants cause wide-ranging damage to macromolecules, including proteins, lipids, DNA and carbohydrates. Oxidative stress is an important pathophysiologic component of a number of diseases, such as Alzheimerâ s disease, diabetes and certain cancers. Cells contain effective defense mechanisms to respond to oxidative stress. Despite much accumulated knowledge about these responses, their kinetics, especially the kinetics of early responses is still not clearly understood. The Yap1 transcription factor is crucial for the normal response to a variety of stress conditions including oxidative stress. Previous studies on Yap1 regulation started to measure gene expression profile at least 20 minutes after the induction of oxidative stress. Genes and pathways regulated by Yap1 in early oxidative stress response (within 20 minutes) were not identified in these studies. Here we study the kinetics of early oxidative stress response induced by the cumene hydroperoxide (CHP) in Saccharomyces cerevisiae wild type and yap1 mutant. Gene expression profiles after exposure to CHP were obtained in controlled conditions using Affymetrix Yeast Genome S98 arrays. The oxidative stress response was measured at 8 time points along 120 minutes after the addition of CHP, with the earliest time point at 3 minute after the exposure. Statistical analysis methods, including ANOVA, k-means clustering analysis, and pathway analysis were used to analyze the data. The results from this study provide a dynamic resolution of the oxidative stress responses in S. cerevisiae, and contribute to a richer understanding of the antioxidant defense systems. It also provides a global view of the roles that Yap1 plays under normal and oxidative stress conditions.
Ph. D.

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15

Cannon, Jordan Krokhmal Pavlo. "Statistical analysis and algorithms for online change detection in real-time psychophysiological data." [Iowa City, Iowa] : University of Iowa, 2009. http://ir.uiowa.edu/etd/342.

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16

Johnson, Wesley Byron. "Design and Testing of a Laboratory Ultrasonic Data Acquisition System for Tomography." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/30938.

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Geophysical tomography allows for the measurement of stress-induced density changes inside of a rock mass or sample by non-invasive means. Tomography is a non-destructive testing method by which sensors are placed around a sample and energy is introduced into the sample at one sensor while the other sensors receive the energy. This process is repeated around the sample to obtain the desired resolution. The received information is converted by a mathematical transform to obtain a tomogram. This tomogram shows a pixelated distribution of the density within the sample. Each pixel represents an average value at that point. The project discussed in this paper takes the principle of ultrasonic tomography and applies it to geomechanics. A new instrumentation system was designed to allow rapid data collection through varying sample geometries and rock types with a low initial investment. The system is composed of sensors, an ultrasonic pulser, a source switchbox, and analog to digital converters; it is tied together using a LabVIEW virtual instrument. LabVIEW is a graphical development environment for creating test, measurement, and other control applications. Using LabVIEW, virtual instruments (VIs) are created to control or measure a process. In this application LabVIEW was used to create a virtual instrument that was automated to collect the data required to construct a tomogram. Experiments were conducted to calibrate and validate the system for ultrasonic velocity determination and stress redistribution tomography. Calibration was conducted using polymethylmethacrylate (PMMA or Plexiglas) plates. Uniaxial loads were placed on limestone and sandstone samples. The stress-induced density contrasts were then imaged using the acquisition system. The resolution and accuracy of the system is described. The acquisition system presented is a low-cost solution to laboratory geophysical tomography. The ultimate goal of the project is to further the ability to non-invasively image relative stress redistribution in a rock mass, thereby improving the engineerâ s ability to predict failure.
Master of Science

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17

Reasons, John. "Modeling Extreme Heat Events Using Global Reanalysis Data: An Assessment of Current Climate Data and the Need for Improved Weather Station Data in Tennessee." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etd/3640.

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Wet Bulb Globe Temperature (WBGT) is used to assess categorical heat stress risk factors for individuals working in outdoor environments and to provide guidelines for work/rest ratios and water intake. The variables required to compute WBGT are used by meteorologists for many purposes and are available through the Copernicus Program which was implemented by European Centre for Medium-Range Weather Forecasts (ECMWF) to provide users access to ECMWF Re-Analysis (ERA) historical database. WBGT values for Tennessee during National Weather Service (NWS) issued excessive heat warnings were calculated to determine the need for additional advisories based on WBGT guidelines. Monthly average WBGT values suggest work/rest ratio thresholds were exceeded in areas with no active heat warnings during the same time. Site assessment for an improved weather station infrastructure was conducted to determine favorability for placement of additional instrumentation to benefit forecasters and general public with greater data availability on a temporal scale.

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18

Pedneau, Emily. "Impact of Combat Stress on Mental Health Outcomes: BRFSS Survey Data 2006." VCU Scholars Compass, 2007. http://scholarscompass.vcu.edu/etd/942.

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Objectives: This study sought to determine the relationship between combat experience and mental health outcomes. The study sought to determine whether age was a significant factor in poor mental health outcomes. Methods: Multiple logistic regression (n = 195,048) and multiple linear regression (n = 264,154) were performed on the 2006 Behavioral Risk Factor Surveillance System (BRFSS) survey. Veteran status and a host of demographic and health status questions were analyzed in relation to diagnosis of anxiety or depressive disorder (multiple logistic regression) and to number of days poor mental health (multiple linear regression). Results: Diagnosis of anxiety or depression was not found to be associated with veteran status. Among both veterans and non-veterans, diagnosis was associated with age Conclusions: Contrary to expectations, veteran status was found to be a protective factor for poor mental health outcomes in this analysis. Younger age was found to be associated with poor mental health outcomes, but was an equal association in both veterans and non-veterans, suggesting that mental health outcomes have not been worsened by recent changes in combat characteristics. Denial of mental health status, stoicism within the military community, and limitations of the survey are proposed to explain the unexpected outcome of this analysis.

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19

Nuñez, Javier Yesid Mahecha. "Cyclists\' physiological stress and network planning and evaluation." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18144/tde-04122018-151933/.

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Transportation planners need to assess users\' stress conditions on cycling infrastructures given that highly stressful situations can discourage the use of this sustainable transport mode. Not many studies have addressed the relationships between these environmental factors and users\' emotional responses in terms of objective measures of stress. The aim of this study is to explore a new approach for planning and evaluating cycling infrastructure, based on smart sensors. This new approach focuses on the perspective of monitoring parameters intrinsic to the user, such as emotions. In this perspective, the indicators of stress levels are made from directly measuring cyclists\' physiological responses throughout the journey. This approach makes use of technological resources to extract information from users through sensors and imparts this information in an integrated way to improve infrastructures for cyclists. The data were collected using stress and noise sensors, accelerometers embedded in a smartphone and a GPS. Initially, the problem is posed and we discuss how the design and evaluation of cycle paths has been addressed in the literature. The proposed approach identifies the most relevant contributions and research gaps, such as the lack of research based on objective criteria and research that involves designing and evaluating infrastructure scenarios shared with motor vehicles. In the sequence, an objective method for assessing bicycle infrastructures combining environmental assessment with vertical acceleration measurements was proposed in order to improving data collection and other procedures required for assessing the main components of cycling infrastructures. Subsequently, a tool to characterize traffic stress of cycling routes, called the Level of Traffic Stress (LTS), was validated with physiological measures in the urban context of a mediumsized Brazilian city. It was observed that there is no correlation and little agreement between the parameters. It is also emphasized that even when incorporating information about the traffic speed to the LTS tool, it was not significantly related to stress from the perspective of the cyclist. In the final analysis the influence of noise, vibration, cycle paths and period of day on stress experienced by cyclists was investigated. An analysis of the p-values and odds ratio confidence intervals shows, with a 95% confidence level, that only the period of the day influenced stress, as confirmed by the data. In this case, the chances of having stress increased by 24% in the afternoon rush hour compared to the morning rush hour. This study showed the feasibility of stress assessment in cyclists using an objective measurement method, as well as quick identification of critical levels of stress.
Os planejadores de transporte precisam avaliar as condições de estresse dos usuários em infraestruturas cicloviárias, uma vez que situações de alto estresse podem desencorajar o uso deste modo de transporte sustentável. Poucas pesquisas têm questionado se existe alguma relação entre esses fatores ambientais e a resposta emocional em termos de medidas objetivas do estresse. O objetivo deste trabalho é explorar a incorporação de sensores inteligentes no planejamento e avaliação da infraestrutura cicloviária. Essa nova abordagem é focada na perspectiva de monitorar parâmetros intrínsecos ao usuário, como as emoções. Nesta perspectiva, os indicadores dos níveis de estresse são feitos a partir da medição direta de respostas fisiológicas em ciclistas ao longo do percurso. Essa abordagem aproveita os recursos tecnológicos para extrair informações dos usuários e permitir o uso dessas informações de forma integrada para melhorar a infraestrutura dos ciclistas. Os dados foram coletados por meio de sensores de estresse, de ruído e acelerômetros incorporados a um smartphone e GPS. Inicialmente é apresentado o problema e como o projeto e avaliação das ciclovias tem sido abordada na literatura. A abordagem proposta permitiu identificar as contribuições mais relevantes e as lacunas de pesquisa, tais como, a falta de pesquisas baseadas em critérios de objetivos e a falta de pesquisas que envolvam o desenho e a avaliação de cenários de infraestrutura compartilhados com veículos automotores. Em seguida foi proposto um método objetivo de avaliação de infraestruturas cicloviárias, combinando a avaliação ambiental com medições de aceleração vertical, a fim de melhorar a coleta de dados e outros procedimentos necessários para avaliar os principais componentes das infraestruturas cicloviárias. Na sequência uma ferramenta para caracterizar o estresse de tráfego de ciclovias, denominada Level of Traffic Stress (LTS), foi validada com medidas fisiológicas no contexto urbano de uma cidade brasileira de porte médio. Observou-se que não há correlação e há pouca concordância entre esses parâmetros. Ressalta-se ainda que, mesmo ao incorporar informações de velocidade de tráfego à ferramenta LTS, não foi significativamente relacionado com estresse medido sob a perspectiva do ciclista. Por fim, foi investigada a influência do ruído, vibração, presencia ou ausência de ciclovias e período do dia no estresse experimentado pelos ciclistas. Uma análise dos valores de p e dos intervalos de confiança das razões de chances mostraram, com um nível de confiança de 95%, que apenas o período do dia influenciou o estresse. Neste caso, as chances de ter estresse aumentaram em 24% na hora pico da tarde em comparação com a hora pico da manhã. Este estudo mostrou a viabilidade da avaliação do estresse em ciclistas por meio de um método de medida objetiva além da rápida identificação dos níveis críticos de estresse.

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20

Ravu, Venkata Sathya Sita J. S. "Compaction Strategies in Apache Cassandra : Analysis of Default Cassandra stress model." Thesis, Blekinge Tekniska Högskola, Institutionen för kommunikationssystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-12850.

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Context. The present trend in a large variety of applications are ranging from the web and social networking to telecommunications, is to gather and process very large and fast growing amounts of information leading to a common set of problems known collectively as “Big Data”. The ability to process large scale data analytics over large number of data sets in the last decade proved to be a competitive advantage in a wide range of industries like retail, telecom and defense etc. In response to this trend, the research community and the IT industry have proposed a number of platforms to facilitate large scale data analytics. Such platforms include a new class of databases, often refer to as NoSQL data stores. Apache Cassandra is a type of NoSQL data store. This research is focused on analyzing the performance of different compaction strategies in different use cases for default Cassandra stress model. Objectives. The performance of compaction strategies are observed in various scenarios on the basis of three use cases, Write heavy- 90/10, Read heavy- 10/90 and Balanced- 50/50. For a default Cassandra stress model, so as to finally provide the necessary events and specifications that suggest when to switch from one compaction strategy to another. Methods. Cassandra single node network is deployed on a web server and its behavior of read and write performance with different compaction strategies is studied with read heavy, write heavy and balanced workloads. Its performance metrics are collected and analyzed. Results. Performance metrics of different compaction strategies are evaluated and analyzed. Conclusions. With a detailed analysis and logical comparison, we finally conclude that Level Tiered Compaction Strategy performs better for a read heavy (10/90) workload while using default Cassandra stress model , as compared to size tiered compaction and date tiered compaction strategies. And for Balanced Date tiered compaction strategy performs better than size tiered compaction strategy and date tiered compaction strategy.

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21

Rastgoo, Mohammad Naim. "Driver stress level detection based on multimodal measurements." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/134144/1/Mohammad%20Naim%20Rastgoo%20Thesis_Redacted.pdf.

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Successful driver performance is fundamental in preventing vehicle crashes. Stress can negatively affect driver performance and significantly increase the risk of a crash. Therefore, an in-vehicle warning system for driver stress levels is needed to continuously predict dangerous driving situations and proactively alert drivers to ensure safe and comfortable driving. As a result of the recent developments in sensing technologies and context recognition, driver stress can be detected using multimodal measurements. This thesis proposes a general framework for building a driver stress level detection system based on multimodal measurements and adopts different approaches to maximise the performance of the system.

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22

Narber, Cody G. "Classification of emotion using sub audible frequencies in vocal data." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/776.

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23

Ask, Maria V. S. "In-situ and laboratory stress investigations using borehole data from the North Atlantic Ocean /." Stockholm : Tekniska högsk, 1998. http://www.lib.kth.se/abs98/ask1215.pdf.

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24

Tricard, Marc J. M. "An expert system for the validation and interpretation of x-ray residual stress data." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-10242009-020322/.

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25

Li, Yingruolan Li. "Confirmatory Factor Analysis with Continuous and Ordinal Data: An Empirical Study of Stress Level." Thesis, Uppsala universitet, Statistiska institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-231196.

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26

Grunberg, Rebecca L. "Timing, mindset, and the link between stress and performance : evidence from experience sampling data." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112035.

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Thesis: Ph. D., Massachusetts Institute of Technology, Sloan School of Management, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 86-92).
This dissertation examines external stressors, perceived stress, and performance, using daily experience sampling data from undergraduate students during their final exam week. First, I investigate external stressors and the timing of perceived stress. Consistent with prior literature, I find that overall perceived stress negatively predicts semester GPA. However, looking more closely at perceived stress over time, I find that perceived stress on exam days did not predict semester grade point average (GPA), while perceived stress on non-exam days significantly negatively predicted semester GPA. Those individuals who experience high perceived stress even outside the temporal bounds of external stressors never have time to recover from the exertion of coping with stress. Then, once individuals feel stressed, one factor that may change how they respond is their beliefs about whether stress is enhancing or debilitating. I investigate the effects of these stress mindsets on the relationship between stress and performance. Results show that stress mindset moderates the relationship between stress and performance, such that the relationship between stress and performance is more negative the more individuals endorse a stress-is-debilitating mindset. I also provide evidence that this effect is partially explained by stress mindset's moderating effect on the relationship between stress and motivation. Together, these findings show that a more complete understanding of the relationship between stress and performance requires examination of both external stressors and perceived stress. Experience sampling methods such as used here provide the opportunity to study all of these variables. This research also has practical implications. Traditional stress management techniques that focus solely on reducing stress may be inadequate at best; both the timing of perceived stress relative to external stressors and individuals' stress mindset provide promising avenues for intervention.
by Rebecca L. Grunberg.
Ph. D.

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27

Semple, Jennifer K. Semple. "Pedigreed Material Property Data for Residual Stress and Distortion Modeling of Naval Steel Weldments." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1533813179740352.

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28

Shrestha, Alina. "Fatigue Testing and Data Analysis of Welded Steel Cruciform Joints." ScholarWorks@UNO, 2013. http://scholarworks.uno.edu/td/1670.

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In this study, ABS Publication 115, “Guidance on Fatigue Assessment of Offshore Structures” is briefly reviewed. Emphasis is on the S-N curves based fatigue assessment approach of non-tubular joints, and both size and environment effects are also considered. Further, fatigue tests are performed to study the fatigue strength of load-carrying and non-load-carrying steel cruciform joints that represent typical joint types in marine structures. The experimental results are then compared against ABS fatigue assessment methods, based on nominal stress approach, which demonstrates a need for better fatigue evaluation parameter. A good fatigue parameter by definition should be consistent and should correlate the S-N data well. The equivalent structural stress parameter is introduced to investigate the fatigue behavior of welded joints using the traction based structural stress approach on finite element models of specimens, and representing the data as a single Master S-N curve.

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29

Sibold, Jeremy S. "A comparison of psychosocial and orthopedic data in predicting days missed due to injury." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3354.

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Thesis (Ed. D.)--West Virginia University, 2004.
Title from document title page. Document formatted into pages; contains iv, 52 p. Includes abstract. Includes bibliographical references (p. 47-52).

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30

Nasiri, Khoozani Ehsan. "An ontological framework for the formal representation and management of human stress knowledge." Thesis, Curtin University, 2011. http://hdl.handle.net/20.500.11937/2220.

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There is a great deal of information on the topic of human stress which is embedded within numerous papers across various databases. However, this information is stored, retrieved, and used often discretely and dispersedly. As a result, discovery and identification of the links and interrelatedness between different aspects of knowledge on stress is difficult. This restricts the effective search and retrieval of desired information. There is a need to organize this knowledge under a unifying framework, linking and analysing it in mutual combinations so that we can obtain an inclusive view of the related phenomena and new knowledge can emerge. Furthermore, there is a need to establish evidence-based and evolving relationships between the ontology concepts.Previous efforts to classify and organize stress-related phenomena have not been sufficiently inclusive and none of them has considered the use of ontology as an effective facilitating tool for the abovementioned issues.There have also been some research works on the evolution and refinement of ontology concepts and relationships. However, these fail to provide any proposals for an automatic and systematic methodology with the capacity to establish evidence-based/evolving ontology relationships.In response to these needs, we have developed the Human Stress Ontology (HSO), a formal framework which specifies, organizes, and represents the domain knowledge of human stress. This machine-readable knowledge model is likely to help researchers and clinicians find theoretical relationships between different concepts, resulting in a better understanding of the human stress domain and its related areas. The HSO is formalized using OWL language and Protégé tool.With respect to the evolution and evidentiality of ontology relationships in the HSO and other scientific ontologies, we have proposed the Evidence-Based Evolving Ontology (EBEO), a methodology for the refinement and evolution of ontology relationships based on the evidence gleaned from scientific literature. The EBEO is based on the implementation of a Fuzzy Inference System (FIS).Our evaluation results showed that almost all stress-related concepts of the sample articles can be placed under one or more category of the HSO. Nevertheless, there were a number of limitations in this work which need to be addressed in future undertakings.The developed ontology has the potential to be used for different data integration and interoperation purposes in the domain of human stress. It can also be regarded as a foundation for the future development of semantic search engines in the stress domain.

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31

Xue, Zeyun. "Integration of high-throughput phenotyping and genomics data to explore Arabidopsis natural variation." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASB001.

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L'azote et l'eau sont essentiels à la survie des plantes ainsi qu'au rendement des cultures, mais les mécanismes moléculaires que les plantes mobilisent en réponse à une déficience en azote (N) en eau (W) et à leur combinaison restent en partie à élucider. Les interconnexions entre l'état hydrique des plantes et la disponibilité de l'azote ont attiré beaucoup d'attention. Étant donné leur importance cruciale, il est très important de disséquer le rôle de chaque stress dans le stress combiné. Nous abordons ici la question de l'intégration des réponses aux stress sécheresse et azoté modérés et de la manière dont ils entravent la croissance des rosettes et le métabolisme des plantes. Dans cette thèse, une investigation systématique a été effectuée pour comprendre comment la carence en azote et en eau se conjuguent pour agir sur la croissance de la rosette chez Arabidopsis. Nous avons intégré des données transcriptomiques et métabolomiques pour obtenir une vue globale des interactions entre sécheresse et stress azoté. De plus, 5 accessions divergentes ont été utilisées pour étudier comment les composants génétiques régulent les réponses au stress, en d'autres termes, les interactions GxWxN. L'évaluation de la déficience en eau, en N et de leur combinaison au niveau transcriptome et métabolome a révélé des signatures de réponse au stress communes et spécifiques qui peuvent être conservées principalement à travers les génotypes, bien que de nombreuses autres réponses spécifiques au génotype aient également été découvertes. Les ajustements des transcriptomes et le profil métabolique spécifiques à l'accession reflètent le niveau physiologique de base distinct de chaque fond génétique, comme Col-0 et Tsu-0. Nous avons également trouvé un sous-ensemble de gènes sensibles au stress qui sont responsables du réglage fin de la réponse combinée au stress, tels que les ROXY, TAR4, NRT2.5, GLN1;4. En outre, nous avons intégré les données transcriptomiques et métabolomiques pour construire un réseau de régulation multi-omique. Deux métabolites réagissant au stress hydrique, le Raffinose et le Myoinositol, ont été mis en évidence par une analyse intégrée montrant des schémas de réponse à la carence en N partagés dans 5 accessions. Cette étude fournit une résolution moléculaire de la variation génétique dans les réponses combinées impliquant des interactions entre la carence en N et le stress hydrique et démontre cette plasticité transcriptomique et métabolomique. En outre, une analyse GWA à grande échelle utilisant un set d’accession mondial a été menée pour déchiffrer l'architecture génétique au niveau métabolique afin de rapprocher la compréhension de la plasticité métabolomique et de la diversité phénotypique et d'étendre notre vision de cette diversité à l'échelle des espèces. La comparaison de l'analyse GWA entre populations régionales et mondiale met en lumière la façon dont la structure de la population peut limiter le pouvoir de détection de l'analyse GWA
Nitrogen and water are crucial for plant survival as well as for crop yield, however the molecular mechanisms that plants mobilise to respond to Nitrogen (N) or Water (W) deficiency and their combination still remain partly unknown. The interconnections between water status and N availability have drawn much attention. Given their critical importance, it is of great importance to dissect the role of each stress in the combined stress. We here address the question of how mild drought and nitrogen stress responses are integrated and how they impaired rosette growth and plant metabolism. In this thesis, a systematic investigation was performed to understand how the N deficiency and drought conjugate to shape dynamic rosette growth in Arabidopsis. We integrated transcriptome and metabolomic data to draw a holistic view of drought x N-deficiency interactions. Moreover, as a case study, 5 highly divergent accessions were used to investigate how genetic components regulate stress responses, in other words, GxWxN interactions. Evaluation of drought, N deficiency and combined stress transcriptomes and metabolomes revealed shared and stress-specific response signatures that were conserved primarily across genotypes, although many more genotype-specific responses also were uncovered. The accession-specific transcriptome adjustments and metabolic profile reflected distinct physiological basal status, such as those of Col-0 and Tsu-0. We also found a subset of stress-responsive genes that are responsible for fine-tuning combined stress response, such as ROXYs, TAR4, NRT2.5, GLN1;4. In addition, we integrated transcriptomic and metabolomic data to construct a multi-omics regulatory network. Two drought stress-responsive metabolites, Raffinose and Myoinositol were highlighted by integrative analysis showing shared N-deficiency patterns in 5 accessions. This study provides molecular resolution of genetic variation in combined stress responses involving interactions between N-deficiency and drought stress and illustrates respective transcriptome and metabolome plasticity. Moreover, large-scale GWA analysis using worldwide populations was conducted to decipher the genetic architecture at the metabolic level and provide links between the metabolomic plasticity and phenotypic diversity behind local adaptation. In addition, this extends our vision of the diversity at the species scale. The comparison of GWA analysis based on regional-scale population and species-wide population also sheds light on how population structure can limit the detection power of GWA analysis

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32

Best, Shawn R. "Detection of residual stress in multi-crystalline silicon wafers using swept-sne frequency response data." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001008.

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33

Boppudi, Srimanth. "Further Investigation of a New Traction Stress Based Shear Strength Characterization Method with Test Data." ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1847.

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In this thesis, a new traction stress based method for characterizing shear strength is investigated by carrying out a series of shear strength tests. The AWS method for the calculation of shear strength shows significant discrepancies between longitudinal and transverse specimens. The main purpose of this new traction based definition for shear strength is to demonstrate that there exists a single shear strength value regardless of specimen geometry and loading conditions. With this new approach a better correlation between shear strength values for transverse and longitudinal specimens is achieved. Special issues occur with the multi-pass welds in regards to the failure angle. The AWS equation does not account to different failure angles of the specimens, it only assumes 45o failure angle in all the cases, but the new approach takes into account the different failure angles. Finally with this method a quantitative weld sizing can be achieved for fillet welds.

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34

Murphy, Michael M. "Defining Stress Changes Ahead of a Tunnel Face and Design of a Data Acquisition System." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/36298.

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With increasing world population, demand for underground construction is expected to accelerate in the future. Design of tunnels in rock is still largely empirical, while rock failure in underground mines and tunnel construction continues to claim lives. A seismic method to aid in increasing safety during excavation is tomography. Seismic tomography is a non-invasive technique to map the stress changes induced by mining ahead of the active face. Seismic tomography maps the velocity distributions of elastic waves traveling through a rock mass. The velocity distributions mapped in the tomograms can relate to anomalies in the rock such as fracture zones and highly concentrated stresses. In order to develop a relationship between stress and elastic wave velocity, laboratory tests in a controlled environment are required. In the current study tomographic tests were conducted on Berea sandstone and Five Oaks limestone samples. The stress redistribution in the sandstone samples could be imaged by mapping velocity distributions. On an unconfined test the sandstone sample acted much like a coal mine pillar where the stress redistributes to the least confined area. On a sandstone test where the sample was indented by a steel platen the velocity contrast was seen directly under the load and the velocity remained almost unchanged over the rest of the sample. For the limestone tests, the stress redistribution could not be mapped in the tomograms. The ability to map the stress distribution in the tomograms were attributed to the elastic and non-elastic characteristics of the stress-strain curve. For sandstone, a porous rock, the stress redistribution could be mapped and for limestone, a stiff rock, the stress redistribution could not be mapped. A field data acquisition system to apply tomography to ground control problems in a mine was designed and calibrated. Data acquisition hardware were assembled and programmed in LabVIEW to collect seismic data in a mine. The design of a geophone array that will fit into a miniature 5.08 cm (2 in) diameter borehole is presented.
Master of Science

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35

Murphy, Michael Martin. "Defining Stress Changes Ahead of a Tunnel Face and Design of a Data Acquisition System." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/36298.

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With increasing world population, demand for underground construction is expected to accelerate in the future. Design of tunnels in rock is still largely empirical, while rock failure in underground mines and tunnel construction continues to claim lives. A seismic method to aid in increasing safety during excavation is tomography. Seismic tomography is a non-invasive technique to map the stress changes induced by mining ahead of the active face. Seismic tomography maps the velocity distributions of elastic waves traveling through a rock mass. The velocity distributions mapped in the tomograms can relate to anomalies in the rock such as fracture zones and highly concentrated stresses. In order to develop a relationship between stress and elastic wave velocity, laboratory tests in a controlled environment are required. In the current study tomographic tests were conducted on Berea sandstone and Five Oaks limestone samples. The stress redistribution in the sandstone samples could be imaged by mapping velocity distributions. On an unconfined test the sandstone sample acted much like a coal mine pillar where the stress redistributes to the least confined area. On a sandstone test where the sample was indented by a steel platen the velocity contrast was seen directly under the load and the velocity remained almost unchanged over the rest of the sample. For the limestone tests, the stress redistribution could not be mapped in the tomograms. The ability to map the stress distribution in the tomograms were attributed to the elastic and non-elastic characteristics of the stress-strain curve. For sandstone, a porous rock, the stress redistribution could be mapped and for limestone, a stiff rock, the stress redistribution could not be mapped. A field data acquisition system to apply tomography to ground control problems in a mine was designed and calibrated. Data acquisition hardware were assembled and programmed in LabVIEW to collect seismic data in a mine. The design of a geophone array that will fit into a miniature 5.08 cm (2 in) diameter borehole is presented.
Master of Science

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36

Webb, Amelinda Erin. "The Effects of Stress on Communities| Using Modern and Fossil Data to Explore Community Response." Thesis, Yale University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3578469.

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The current biodiversity crisis is challenging the ability of conservation biologists to both monitor ongoing declines and create effective management plans. Ongoing habitat destruction, pollution, introduction of invasive species, and the initial stages of climate change are only some of the anthropogenic stresses that face today's biosphere. On human time scales, these changes are unprecedented, curtailing the availability of knowledge regarding ecological responses to stress and disturbance. The fossil record provides numerous disturbances of varying magnitudes throughout the history of life, and yet this resource has been often overlooked or dismissed by biologists. The purpose of this study is to examine the effects of stress on communities using methods that allow integration of modern and fossil data. With this goal in mind, various levels of disturbance are investigated across increasing temporal and spatial scales.

At the smallest spatial and temporal scale, I examined the effect of recent lake acidification on plankton communities, using techniques commonly applied by ecologists, as well as introducing a new method based on a well-established technique. Throughout this thesis, I use the Buzas-Gibson evenness metric and Non-metric Multi-Dimensional Scaling analysis (an ordination technique), as well as applying Rank-Abundance Curve Kurtosis, which measures the shape of species-abundance distributions. Each of these techniques is a different way of representing community structure, with each metric providing slightly different information. Within the lake acidification system, all communities displayed a shift in community structure as pH dropped, and again when pH values returned to neutral, indicating a gradual recovery from acid stress. The timing of this change reveals the ability of different communities to resist acidification, and the resilience of those communities through the recovery phase.

To determine the feasibility of comparing modern and fossil data, I selected four unrelated datasets with distinct disturbance events to represent different time scales, from two decades to one million years. Each dataset displayed a similar pattern; the disturbance event created a distinct shift in community structure followed by a gradual recovery after the stress levels decreased. A major concern when comparing modern and fossil data is the difference in temporal resolution, and specifically the effect of time-averaging which is expected to obscure ecological signals. Instead, I found that applying a model of time-averaging across the community data reduced background noise, thereby clarifying the pattern of ecological change observed in the raw data.

Extending the temporal and spatial scale, I explored the ecological response of marine microfossil assemblages during three intervals of rapid global warming, as analogues for modern global warming. Four taxonomic groups were included, two benthic and two planktic. Overall, diversity within communities increased during global warming, however this was due to the response of the planktic groups, as both benthic groups showed decreases in diversity. These findings support the utility of the fossil record in examining past disturbances, by providing a useful prediction for biotic responses to global warming.

Representing the largest spatial and temporal scale is the Botomian mass extinction (mid-Early Cambrian). This mass extinction is the first recognized mass extinction in the history of life, and occurred during an interval of rapid evolution and faunal turnover. During the extinction interval, there was a distinct change in community structure and an associated increase in instability.

The findings of this study are unique; community structure displays a similar response to stress across various taxonomic groups, in different environments, and at multiple temporal scales. The commonality in community response to stress likely represents a fundamental feature of disturbed ecosystems. Not only is the comparison of modern and fossil data possible, such comparisons offer new discoveries relevant to conservation biology and about the very nature of life on Earth.

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37

Roshanaei, Sina. "Stress-Strain data for metals in bar and sheet form : strain rate, thickness and temperature influences." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15614.

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Over the past few decades various models of different formats have been developed to correctly evaluate and predict the strength of materials. However, these models are limited in certain environmental conditions in implementing the effect of material's thickness into their models. As such an there was a need to consider the basics of mechanical engineering and to try and define the trend, thickness has upon the behaviour of materials with respect to environmental conditions. The work consisted of a representation of tensile testing testing of common engineering alloys across a wide range of temperature, strain rate and thickness. Acquisition of high strain rate data and extended strain data (split-hopkinson, bulge forming and plane strain compression). A review of existing graphical techniques and limited applications using strength reduction factors, as well as applying the accepted empirical formulae, Johnson-Cook, Armstrong-Zerrili, Ramberg-Osgood and Hollomon. Later, recognising a need for a new approach as with a universal (quartic) polynomial fit to all plastic flow curves in which coefficients are T, ε̇ and t̄ dependant. Adoptation of a common numerical procedure for strain intercept ε0 and cut-off instability co-ordinates (σi, εi)- each as the solution to the roots of a quartic. Therefore, a proposal of the flow curve tables allowing interpolation and extrapolation, a numerical representation of any previous "Atlas of Curves". Subsequently, leading to reconstruction of the full stress-strain curve with the addition of elastic strain calculated from the modulus applicable to the specific test condition by further testing of these data from literature; both improving the existing and producing new empirical and simulation based models to analyse the materials, which will be subjected to dynamic loading as well as temperature and strain rates variations. The main objective of the work, was involved in creating a polynomial fit to describe the three physical conditions in terms of coefficients and to verify the findings in a FEA package, ABAQUS. A new process in reading the stress-strain data. By means of such development an instability study of strain limits based on Considére criteria was developed which illustrated the ways to prolong the instability limit. A secondary study of this work relates to creating a bridge between the micro-structure and macro-structure of the tested materials. A series of correlations and trends were developed to further signify the shift in micro-structural restructuring, whilst the material is under load. Another important aspect of the work consists, of carrying out an analytical study on Ramberg-Osgood equation. Ramberg-Osgood equation has been at the forefront of many engineering advancement. However it can yet be improved and reformatted by means of defining a set value for its variable constants. As such a fix ƞt value based on a best-fit approach was developed which was analytically tested.

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38

Salles, Lucio Salles de. "Short continuously reinforced concrete pavement design recommendations based on non-destructive ultrasonic data and stress simulation." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3138/tde-20102017-082704/.

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Four sections of continuously reinforced concrete pavement (CRCP) were constructed at the University of São Paulo campus in order to introduce this kind of pavement structure to Brazil\'s technical transportation community. Sections were designed as 50 m long concrete slab, short in comparison to traditional CRCP, in order to simulate bus stops and terminals - locations of critical interest for public infrastructure. The thesis presented herein concludes this research project initiated in 2010. As the initial goal of this study was the development of coherent, reliable and intuitive design recommendations for the use of CRCP technology in Brazil, a profound understating of its structural and performance peculiarities was needed. For that, the cracking process of the experimental CRCP sections was recorded over a span of seven years. Due to the sections\' short length and lack of anchorage, the experimental \"short\" CRCP presented a cracking behavior quite different than traditional CRCP. There were much less visible cracks than expected. To address this issue, a novel technology in ultrasonic non-destructive testing of concrete structures was applied. Through ultrasonic signal interpretation it was possible to discover several incipient non-visible cracks within the slabs - many of these became apparent on the slab surface in later crack surveys - and to characterize visible and non-visible cracks regarding crack depth. The updated crack map with non-visible cracks showed similarities with traditional CRCP. Additionally, the ultrasonic data analysis provided important information on thickness variation, reinforcement location and concrete condition that were applied in theoretical simulations (finite element software) of the short CRCP. Simulations were attempted considering different slab geometries, firstly with transverse cracks as joints with high load transfer efficiency (LTE) and secondly with a continuous slab without cracks or joints. The latter simulation was more accurate reaching a shift factor between field and simulated stresses in the order of 0.7 to 1.0. Deflection data and LTE analysis from cracks and panels in between cracks further attested the slab continuous behavior, which contradicts current CRCP design models and performance predictors. Furthermore, critical traffic and environmental loading conditions concerning Brazil\'s climate and bus traffic characteristics were investigated and related using a selected fatigue model resulting in design recommendations in a chart format for the short CRCP aimed at long-term projects for over 20 years of operation. The design chart was successfully applied to investigate three failures presented by the experimental short CRCP due to thickness deficiencies pointed out by the ultrasonic testing.
Quatro seções de pavimento de concreto continuamente armado (PCCA) foram construídas no campus da Universidade de São Paulo, com o objetivo de introduzir esta estrutura, de reconhecido sucesso internacional, à comunidade técnica de engenharia de transportes brasileira. As seções foram projetadas com uma placa de concreto de 50 m de extensão, curta em comparação ao PCCA tradicional, com a finalidade de simular paradas e terminais de ônibus - locais de grande interesse para a infraestrutura pública. A tese aqui apresentada conclui este projeto de pesquisa iniciado em 2010. Como o objetivo inicial deste estudo foi o desenvolvimento de recomendações de projeto coerentes, confiáveis e intuitivas para a utilização do PCCA no Brasil, foi necessário um profundo entendimento de suas peculiaridades estruturais e de desempenho. Para isso, o processo de fissuração das secções experimentais foi acompanhado durante sete anos. Devido à curta extensão e falta de ancoragem das seções, o PCCA \"curto\" apresentou um padrão de fissuração diferente do PCCA tradicional com muito menos fissuras visíveis na superfície do que o esperado. Para abordar esta questão, uma nova tecnologia ultrassônica para ensaios não destrutivos de estruturas de concreto foi aplicada. Pela interpretação do sinal de ultrassom, foi possível descobrir várias fissuras incipientes (não visíveis) dentro das placas - muitas dessas foram observadas na superfície da placa em levantamentos de fissuras posteriores - e caracterizar fissuras visíveis e não-visíveis quanto à profundidade da fissura. O mapa de fissuração atualizado com fissuras não visíveis mostrou semelhanças com PCCA tradicional. Além disso, a análise dos dados de ultrassom forneceu informações importantes sobre a variação da espessura, localização da armadura longitudinal e condição do concreto, que foram aplicados em simulações teóricas (software de elementos finitos) do PCCA curto. Simulações foram propostas considerando diferentes geometrias, primeiramente com fissuras transversais como juntas com alta eficiência de transferência de carga (LTE) e posteriormente com uma placa contínua, sem fissuras ou juntas. Esta última simulação foi mais precisa alcançando um fator de conversão entre tensões de campo e simuladas na ordem de 0,7 a 1,0. Dados de deflexão e análise de LTE em fissuras e placas entre fissuras atestaram novamente o comportamento contínuo das placas, o que vai em contradição com os modelos atuais de dimensionamento e de previsão de desempenho para o PCCA. Ademais, o tráfego crítico e condições de carga ambiental correspondentes ao clima e tráfego de ônibus típicos brasileiros foram investigados e relacionados usando um modelo de fadiga resultando em recomendações de projeto para o PCCA de curta extensão sendo direcionado para projetos de longo prazo para mais de 20 anos de operação. O gráfico de projeto foi aplicado com sucesso para investigar três falhas apresentadas pelo PCCA curto experimental devido a deficiências de espessura apontadas pelo teste ultrassônico.

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39

Carpenter, John Stuart. "Estimates of Interfacial Properties in Cu/Ni Multilayer Thin Films using Hardness and Internal Stress Data." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1285006915.

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40

Polanski, Krzysztof. "Finding network modules and motifs regulating plant stress responses : integration and modelling across multiple data sets." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/77390/.

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In spite of constant technological advancements, world hunger remains a major challenge due to exponential population growth, and the loss of e effectiveness of crop treatments such as pesticides. As such, comprehending the plant response to stress is of great importance in breeding more resilient crops. Whilst different stresses elicit distinct responses from the plant, a core set of regulatory interactions are conserved across multiple responses and operate as networks. In this thesis, computational approaches were used to elucidate such regulatory interactions from time course expression datasets, predominantly through identification of genes co-expressed across multiple stimuli responses as a footprint of shared network co-regulation. The identification of such network footprints was tackled through Wigwams, a data mining algorithm capable of detecting groups of genes co-regulated across multiple datasets. In contrast to other algorithms, Wigwams assesses whether the co-expression it detects is likely to reflect co-regulation. The modules it found were significantly enriched in functionality and cis-regulatory elements, indicating actual co-regulation. Wigwams and other computational approaches were applied to time course expression data capturing Arabidopsis thaliana response to Pseudomonas syringae pv. tomato DC3000. The presence of a virulent and avirulent strain in the experiment allowed for the temporal deconstruction of the regulatory events underlying the virulent strain's attempts to overcome plant defence through effector action. This analysis led to the detection of a number of effector-specific transcription changes stifling the defence response and manipulating the host's gene and protein expression. A transcription factor-only regulatory network model was proposed to explain the detected network footprints. The inference of causal regulatory networks from expression data is a daunting task, and transcription factor-only models are a good computational compromise by capturing the key regulatory events taking place. However, they are lacking in target genes that carry out the functionality induced by the signalling, making functional assessment di cult. Wigwams was used to introduce the network footprint components into the corresponding transcription factor-only models, resulting in enhanced network models carrying information about downstream regulated genes. This allows for functional assessment to be used to identify nodes of interest within the network, and propose concise follow-up experiments.

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41

Fritz, Godfried. "The relationship of sense of coherence to health and work in data processing personnel." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/16845.

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Bibliography: pages 80-86.
The aim of the present study was to test a model of stress and to examine whether the theoretical construct of sense of coherence (SOC) moderated the relationship between stressors and health-related and work-related outcomes. This construct of SOC was identified by an Israeli medical sociologist, Antonovsky. He maintained that the current focus of research on stress is largely pathogenic in nature. He suggested that it would be of value to shift research more towards that which identifies the origins of health. He consequently developed the term "salutogenesis", which requires people to focus on those factors which promote well-being. He also argued that people are not either sick or well, but rather are located on a continuum between health-ease/dis-ease. With respect to their health, persons will find themselves somewhere along this continuum, where they may shift between the two positions. He then suggests that certain factors contribute to facilitating the movement along this continuum. These factors together form a construct which he calls the SOC. The SOC is comprised of core components. He hypothesizes that someone with a strong SOC is likely to make better sense of the world around him/her, thereby engendering resilience towards the impinging stressors. The person with a weak SOC is likely to capitulate to these stressors · more readily and by succumbing to them is going to increase the likelihood that (s)he will move to the dis-ease end of the continuum. This study attempted to investigate the following research questions, namely, whether (1) the stressors were related to the stress outcomes, (2) the SOC was related to the stressors and outcomes, and (3) the SOC moderated the relationships between stressors and outcomes. In the present study the subjects were drawn from all data processing professionals in a large financial organisation. The respondents (~ = 194) replied to a questionnaire which contained scales which measured a variety of job-related stressors, an SOC scale as well as job-related and health-related outcome variables. Intercorrelations between the stressor, moderator and outcome variables were calculated. Other statistical procedures that were utilized were subgroup analyses and the moderated multiple regression analyses. Partial support for all three research questions was obtained. Four of the six stressors were found to correlate significantly with somatic complaints, thereby suggesting that stressors result in persons feeling the results of stress and reporting them physically. The SOC was found to relate to some of the stressors and outcome variables. This would lend partial support to an interpretation of the SOC as having a main effect relationship to stressor and outcome variables. In the subgroup analyses the results showed that out of a possible 54 relationships, the SOC moderated in only seven of them that the moderated multiple regression (MMR) analyses showed out of 54 possible relationships, the SOC moderated in 12 of them health-related variables. Furthermore, the SOC moderated between six outcome variables and six work-related outcomes. These findings then partially support research question 3, which examined whether the SOC would moderate relationships between stressors and outcome variables. This study was concluded by a discussion of the findings, its implications, and the limitations of this research.

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42

Madjar, Nicole, and Filip Lindblom. "Machine Learning implementation for Stress-Detection." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280897.

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This project is about trying to apply machine learning theories on a selection of data points in order to see if an improvement of current methodology within stress detection and measure selecting could be applicable for the company Linkura AB. Linkura AB is a medical technology company based in Linköping and handles among other things stress measuring for different companies employees, as well as health coaching for selecting measures. In this report we experiment with different methods and algorithms under the collective name of Unsupervised Learning, to identify visible patterns and behaviour of data points and further on we analyze it with the quantity of data received. The methods that have been practiced on during the project are “K-means algorithm” and a dynamic hierarchical clustering algorithm. The correlation between the different data points parameters is analyzed to optimize the resource consumption, also experiments with different number of parameters are tested and discussed with an expert in stress coaching. The results stated that both algorithms can create clusters for the risk groups, however, the dynamic clustering method clearly demonstrate the optimal number of clusters that should be used. Having consulted with mentors and health coaches regarding the analysis of the produced clusters, a conclusion that the dynamic hierarchical cluster algorithm gives more accurate clusters to represent risk groups were done. The conclusion of this project is that the machine learning algorithms that have been used, can categorize data points with stress behavioral correlations, which is usable in measure testimonials. Further research should be done with a greater set of data for a more optimal result, where this project can form the basis for the implementations.
Detta projekt handlar om att försöka applicera maskininlärningsmodeller på ett urval av datapunkter för att ta reda på huruvida en förbättring av nuvarande praxis inom stressdetektering och åtgärdshantering kan vara applicerbart för företaget Linkura AB. Linkura AB är ett medicintekniskt företag baserat i Linköping och hanterar bland annat stressmätning hos andra företags anställda, samt hälso-coachning för att ta fram åtgärdspunkter för förbättring. I denna rapport experimenterar vi med olika metoder under samlingsnamnet oövervakad maskininlärning för att identifiera synbara mönster och beteenden inom datapunkter, och vidare analyseras detta i förhållande till den mängden data vi fått tillgodosett. De modeller som har använts under projektets gång har varit “K-Means algoritm” samt en dynamisk hierarkisk klustermodell. Korrelationen mellan olika datapunktsparametrar analyseras för att optimera resurshantering, samt experimentering med olika antal parametrar inkluderade i datan testas och diskuteras med expertis inom hälso-coachning. Resultaten påvisade att båda algoritmerna kan generera kluster för riskgrupper, men där den dynamiska modellen tydligt påvisar antalet kluster som ska användas för optimalt resultat. Efter konsultering med mentorer samt expertis inom hälso-coachning så drogs en slutsats om att den dynamiska modellen levererar tydligare riskkluster för att representera riskgrupper för stress. Slutsatsen för projektet blev att maskininlärningsmodeller kan kategorisera datapunkter med stressrelaterade korrelationer, vilket är användbart för åtgärdsbestämmelser. Framtida arbeten bör göras med ett större mängd data för mer optimerade resultat, där detta projekt kan ses som en grund för dessa implementeringar.

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43

Alder, Emma K. "Temporomandibular Joint Disorder: An Investigation of Masseter Muscle Activity in Response to Stressful Computer Data Entry." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1339772763.

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44

Chavez, Jacqueline A. "Principal stress analysis of rock fracture data from the Long Beach oil field, Los Angeles basin, California." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1587889.

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Twelve electric borehole-image logs from oil wells located in the Long Beach oil field were used to conduct a fracture analysis of principal stress orientations associated with the Newport-Inglewood Fault Zone. The fractures analyzed are located in the Puente, Repetto, Pico, and San Pedro formations. Fractures were grouped based on fracture type, orientation, and formation. In-situ SHmax orientation was interpreted to range between 320? to 40?. Variations form the in-situ stress were observed across every formation and interpreted as paleo-stress. The SHmax orientation begins to change from NW to N-NW in the Pico Formation, which may signal the onset of the dextral movement of the Newport-Inglewood Fault 2.5 million years ago or later. The NE SHmax orientation in the San Pedro Formation may reflect stress trajectory changes as the Newport-Inglewood Fault continues to propagate in the Pleistocene. Additional SHmax orientations indicate a more complex structural evolution of stress trajectories.

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45

Petersson, Sven. "Simulation of Phase Contrast MRI Measurements from Numerical Flow Data." Thesis, Linköping University, Department of Biomedical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-14871.

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Phase-contrast magnetic resonance imaging (PC-MRI) is a powerful tool for measuring blood flow and has a wide range of cardiovascular applications. Simulation of PC-MRI from numerical flow data would be useful for addressing the data quality of PC-MRI measurements and to study and understand different artifacts. It would also make it possible to optimize imaging parameters prior to the PC-MRI measurements and to evaluate different methods for measuring wall shear stress.

Based on previous studies a PC-MRI simulation tool was developed. An Eulerian-Lagrangian approach was used to solve the problem. Computational fluid dynamics (CFD) data calculated on a fix structured mesh (Eulerian point of view) were used as input. From the CFD data spin particle trajectories were computed. The magnetization of the spin particle is then evaluated as the particle travels along its trajectory (Lagrangian point of view).

The simulated PC-MRI data were evaluated by comparison with PC-MRI measurements on an in vitro phantom. Results indicate that the PC-MRI simulation tool functions well. However, further development is required to include some of the artifacts. Decreasing the computation time will make more accurate and powerful simulations possible. Several suggestions for improvements are presented in this report.

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46

Murphy, Ryan C. "Heat stress vulnerability as predicted by spatial analysis of remotely sensed imagery and socioeconomic data for Philadelphia, PA." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 61 p, 2009. http://proquest.umi.com/pqdweb?did=1885544271&sid=1&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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47

Shreedharan, Srisharan. "Stability Investigations of Tunnels in a Coal Mine in China Through 3D-Discontinuum Numerical Modeling and Field Deformation Monitoring Data." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/612541.

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An imperative task for successful underground mining is to ensure the stability of underground structures, since it influences the safety, and in turn, the production capacity and economic performance of the mine. This is more so for deep excavations in soft rock which may be under significantly high stresses. In this thesis, stability studies on two tunnels, a horseshoe-shaped and an inverted arch-shaped tunnel, have been presented. The tunnels, running at a depth of 1325 m, are part of the Xiezhuang Coal Mine, in the Xinwen mining area, in China. Using the available information on stratigraphy, geological structures, in-situ stress measurements and geo-mechanical properties of intact rock and discontinuity interfaces, a three-dimensional numerical model has been built using the 3DEC 3-Dimensional Distinct Element Code to simulate the stress conditions around the tunnels. Based on available discontinuity geometry constraints, the rock mass has been modelled as a mixture of a discontinuum medium close to the tunnels and as an equivalent-continuum in the far field. Due to the unavailability of field measurements for rock mass mechanical parameters, the parameters have been estimated by incorporating the available intact rock mechanical properties and field deformation monitoring data into a strength reduction model calibration procedure. This back-analysis (calibration) has been carried out through a pseudo-time dependent support installation routine which incorporates the effect of time through a stress-relaxation mechanism. The results from the back-analysis indicate that the rock mass cohesion, tensile strength, uniaxial compressive strength, and elastic modulus values are about 35-45 % of the corresponding intact rock property values. Additionally, the importance of incorporating stress relaxation before support installation in numerical modeling has been illustrated, for the first time in literature, through the increased support factors of safety and reduced grout failures. The calibrated models have been analyzed for different supported and unsupported cases in an attempt to quantify the effect of supports in stabilizing the tunnels and to estimate the adequacy of the existing supports being used in the mine. A direct outcome is that the findings indicate that longer supports may be better suited for the existing geo-mining conditions around the tunnels since they have fractured zones that are larger than the supports currently in use at the mine. The effects of supports have been demonstrated using changes in deformations and yield zones around the tunnels, and changes in the average factors of safety and grout failures of the supports. The use of longer supports and floor bolting has provided greater stability for the rock masses around the tunnels. A comparison between the closure strains in the two differently shaped tunnels indicates that the inverted arch tunnel may be more efficient in reducing roof sag and floor heave for the existing geo-mining conditions. Additional analyses focusing on parametric sensitivity studies on the rock and joint mechanical properties show that the tunnel stability is highly sensitive to changes in cohesion and internal friction angle of the intact rock, and changes in joint basic friction angle. Tunnel stability is seen to not be very sensitive to changes in intact rock tensile strength and joint shear stiffness for the tunnels being studied. Finally, support optimization studies conducted by studying the effect of changing cable diameters and grout uniaxial compressive strengths on support factors of safety and grout failures show the trade-off that is necessary in selecting cable strength vis-à-vis grout strength. The results indicate that simply increasing either one of cable or grout strength parameters without considering their interactions and compatibilities could be detrimental to the stability of the support system.

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48

Allard, Christopher E. "Development of a non-destructive optical method to measure residual stress in thin rectangular samples employing digital image processing." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/20645.

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49

Griebel, Matthew Alexander. "Viscoelastic Anisotropic Finite Element Mixture Model of Articular Cartilage using Viscoelastic Collagen Fibers and Validation with Stress Relaxation Data." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/743.

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Experimental results show that collagen ﬁbers exhibit stress relaxation under tension and a highly anisotropic distribution. To further develop the earlier model of Stender [1], the collagen constituent was updated to reﬂect its intrinsic viscoelasticity and anisotropic distribution, and integrated with an existing mixture model with glycosaminoglycans and ground substance matrix. A two-term Prony series expansion of the quasi-linear viscoelastic model was chosen to model the viscoelastic properties of the collagen ﬁbers. Material parameters were determined by using the simplex method to minimize the sum of squared errors between model results and experimental stress relaxation data of tissue in tension. Collagen elastic ﬁber modulus was calculated by ﬁtting to the equilibrium data and viscoelastic parameters were determined by ﬁtting to the relaxation curve. Results of newborn (~1-3 week old) untreated bovine articular cartilage explants from the patellar femoral groove as well as explants cultured in transforming growth factor-β1 (TGF-β1), from both the superﬁcial (~0-0.5 mm from the articular surface) and middle (~0.5-1.0 mm from the articular surface) layers were compared to examine the effects of TGF- β1. TGF-β1 has been shown to maintain or even enhance mechanical properties of articular cartilage in compression and tension [2, 3] and this study continues with the hope that it may be used to improve tissue engineering of mature cartilage to better survive implantation in vivo for the successful repair of articular cartilage defects. Results show that TGF-β1 has a maturational effect on collagen, causing the tissue to become stiffer through an increase in elastic collagen ﬁber modulus and less viscous through shorter relaxation time and less stress relaxation (tissue retained a higher percentage of residual stress). The results of this study further advance the understanding of the effects of location and treatment with TGF-β1.

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50

Al-Sho'ala, Afaf Sayed Ali. "Evaluation of wet bulb globe temperature index for a population adapted to work in the heat : and development of a heat stress limit for occupational accident prevention predicted from meteorological data and building design." Thesis, University of London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339094.

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Дисертації з теми "Stress data"

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