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SAR remote sensing of soil moistureSnapir, Boris January 2014 (has links)
Synthetic Aperture Radar (SAR) has been identified as a good candidate to provide high-resolution soil moisture information over extended areas. SAR data could be used as observations within a global Data Assimilation (DA) approach to benefit applications such as hydrology and agriculture. Prior to developing an operational DA system, one must tackle the following challenges of soil moisture estimation with SAR: (1) the dependency of the measured radar signal on both soil moisture and soil surface roughness which leads to an ill-conditioned inverse problem, and (2) the difficulty in characterizing spatially/temporally surface roughness of natural soils and its scattering contribution. The objectives of this project are (1) to develop a roughness measurement method to improve the spatial/temporal characterization of soil surface roughness, and (2) to investigate to what extent the inverse problem can be solved by combining multipolarization, multi-incidence, and/or multi-frequency radar measurements. The first objective is achieved with a measurement method based on Structure from Motion (SfM). It is tailored to monitor natural surface roughness changes which have often been assumed negligible although without evidence. The measurement method is flexible, a.ordable, straightforward and generates Digital Elevation Models (DEMs) for a SAR-pixel-size plot with mm accuracy. A new processing method based on band-filtering of the DEM and its 2D Power Spectral Density (PSD) is proposed to compute the classical roughness parameters. Time series of DEMs show that non-negligible changes in surface roughness can happen within two months at scales relevant for microwave scattering. The second objective is achieved using maximum likelihood fitting of the Oh backscattering model to (1) full-polarimetric Radarsat-2 data and (2) simulated multi-polarization / multi-incidence / multi-frequency radar data. Model fitting with the Radarsat-2 images leads to poor soil moisture retrieval which is related to inaccuracy of the Oh model. Model fitting with the simulated data quantifies the amount of multilooking for di.erent combinations of measurements needed to mitigate the critical e.ect of speckle on soil moisture uncertainty. Results also suggest that dual-polarization measurements at L- and C-bands are a promising combination to achieve the observation requirements of soil moisture. In conclusion, the SfM method along with the recommended processing techniques are good candidates to improve the characterization of surface roughness. A combination of multi-polarization and multi-frequency radar measurements appears to be a robust basis for a future Data Assimilation system for global soil moisture monitoring.
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Vybrané pohybové trendy a jejich vliv na stabilizační funkci trupu u dialyzovaných pacientů - literární rešerše. / Selected exercise trends and its effect on trunk stabilization function in dialysed patients - overview of the literature.Burianová, Katarína January 2016 (has links)
Title: Selected exercise trends and its effect on trunk stabilization function in dialysed patients - overview of the literature. Objective: Objective of this diploma thesis was to obtain and compare available studies dealing with exercise trends such as yoga, pilates, tai chi and balance training devices and to evaluate their effect on musculature which participates on trunk stabilization system of dialysed patients. Methods: This diploma thesis has descriptively-analytical character and is structured in a form of literary review. Results: Issue of dialysis in connection with trunk stabilization system has not been sufficiently explored yet in literary sources.In conclusion, there were no studies found dealing with effects of particular exercise trends on spine stabilization system of dialysed patients.In order to comprehend this issue an overview was written to define the effect of such trends on dialysed patients. Also, complications arising from renal failure and dialysis were mentioned such as hypertension, diabetes melitus and obesity.The effect of these trends on trunk stabilization system of healthy population as well as patients suffering from chronic back pain was described too. Conclusion: Some extent of coherence was found between strengthening musculature which plays an important role...
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Finanční analýza CHI Czech, s.r.o. / Financial Analysis CHI Czech, s.r.o.Vašáková, Iva January 2009 (has links)
The aim of this dissertation is to test the financial position of companies operating cafe chains in the Czech Republic. It concentrates on the company CHI Czech s.r.o., which runs the cafe chain coffeehaven. The analysis of the financial viability of the company is tested via set of analytical index and the company's results are compared with results achieved by other cafe chains.
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Risk Management ProjectYan, Lu 02 May 2012 (has links)
In order to evaluate and manage portfolio risk, we separated this project into three sections. In the first section we constructed a portfolio with 15 different stocks and six options with different strategies. The portfolio was implemented in Interactive Brokers and rebalanced weekly through five holding periods. In the second section we modeled the loss distribution of the whole portfolio with normal and student-t distributions, we computed the Value-at-Risk and expected shortfall in detail for the portfolio loss in each holding week, and then we evaluated differences between the normal and student-t distributions. In the third section we applied the ARMA(1,1)-GARCH(1,1) model to simulate our assets and compared the polynomial tails with Gaussian and t-distribution innovations.
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Risk Management ProjectShen, Chen 02 May 2012 (has links)
In order to evaluate and manage portfolio risk, we separated this project into three sections. In the first section we constructed a portfolio with 15 different stocks and six options with different strategies. The portfolio was implemented in Interactive Brokers and rebalanced weekly through five holding periods. In the second section we modeled the loss distribution of the whole portfolio with normal and student-t distributions, we computed the Value-at-Risk and expected shortfall in detail for the portfolio loss in each holding week, and then we evaluated differences between the normal and student-t distributions. In the third section we applied the ARMA(1,1)-GARCH(1,1) model to simulate our assets and compared the polynomial tails with Gaussian and t-distribution innovations.
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Comparação do equilíbrio entre idosos saudáveis praticantes e não praticantes de Tai Chi Chuan / Assessment of balance in healthy elderly: comparison between practitioners of Tai Chi Chuan and non-practitionersRahal, Miguel Antônio 31 August 2009 (has links)
Quedas no idoso pode ser um evento devastador. Deve ser estimulada a conscientização desse grupo quanto aos benefícios de se manterem ativos. O tai chi chuan é um exercício de prática esportiva moderada que demonstra aumento no equilíbrio, marcha e postura. O objetivo foi avaliar a influência dessa modalidade no equilíbrio, postura e marcha de idosos ativos e saudáveis. Foi realizado um estudo transversal controlado com 76 voluntários, com 51 participantes da atividade para o equilíbrio, idade média de76, 8 anos. Foram utilizados quatro testes do Sistema Balance Master da Neurocom. Para análise dos dados a comparação das idades nos dois grupos utilizou-se o teste de Mann-Whitney (Siegel, 2006). O mesmo teste foi utilizado para todas as comparações entre os dois grupos quanto ao Teste Clínico Modificado da Interação Sensorial para o Equilíbrio (TCISEM), Teste da Caminhada (TC), Teste da Transferência de Sentado para em Pé (TSP) e Teste da avaliação Unipodal (TUP). O grupo do tai chi chuan apresentou valores significativos no equilíbrio e maior capacidade de recuperação. / Falls in the elderly can be a devastating event. Should be encouraged awareness about the benefits of this group to remain active exercises. Tai-chi-chuan is an exercise in sports practice demonstrates that moderate increases in balance, gait and posture. The objective was to evaluate the influence of this modality in the balance, posture and gait of elderly people active and independent. Was conducted a cross-controlled study with 76 volunteers, with 51 participants in the activity for the balance, average age de76, 8 years. We used four tests of the system\'s Balance Master Neurocom.For analysis of the data to compare the two age groups using the Mann-Whitney test (. Siegel, 2006). The same test was used for all comparisons between the two groups on the Modified Clinical Test of Sensory Integration for the balance (TCISEM), the Walk Test (CT), Test of the Transfer of sitting for standing (TSP) and Test of the evaluation Leg (TUP). The group of tai chi chuan showed significant values in the balance and gait.
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Comparison Between Confidence Intervals of Multiple Linear Regression Model with or without ConstraintsTao, Jinxin 27 April 2017 (has links)
Regression analysis is one of the most applied statistical techniques. The sta- tistical inference of a linear regression model with a monotone constraint had been discussed in early analysis. A natural question arises when it comes to the difference between the cases of with and without the constraint. Although the comparison be- tween confidence intervals of linear regression models with and without restriction for one predictor variable had been considered, this discussion for multiple regres- sion is required. In this thesis, I discuss the comparison of the confidence intervals between a multiple linear regression model with and without constraints.
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Inference in Constrained Linear RegressionChen, Xinyu 27 April 2017 (has links)
Regression analyses constitutes an important part of the statistical inference and has great applications in many areas. In some applications, we strongly believe that the regression function changes monotonically with some or all of the predictor variables in a region of interest. Deriving analyses under such constraints will be an enormous task. In this work, the restricted prediction interval for the mean of the regression function is constructed when two predictors are present. I use a modified likelihood ratio test (LRT) to construct prediction intervals.
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Är företagssubventionerad friskvård lönsamt? / Are companies subsidized fitness profitable?Klingberg, David, Thorvaldsson, Daniel January 2009 (has links)
Enligt vår teoretiska referensram samt enligt en undersökning som genomfördes åt Statensoffentliga utredninger, (SOU 1997:188), kan ett samband mellan motionsutövande och hälsapåvisas. Det finns däremot ingen entydig forskning som visar på att motionsutövande leder tillminskad sjukfrånvaro. Vår studie utgår från grundhypotesen att det finns ett positivt sambandmellan företagssubventionerad friskvård och minskad sjukfrånvaro. Genom enenkätundersökning där 48 ICA-butiker medverkade samt där butikernas årsredovisningargranskades, insamlades data relaterad till butikernas friskvårdssubventionering ochsjukfrånvaro. Enligt ett Chi-square test kunde ett svagt samband mellanfriskvårdssubventionering och sjukfrånvaro skönjas, och även beräkningarna för korrelationenmellan de två variablerna för den insamlade datamängden påvisade ett samband.Nyttjandegraden av friskvårdsbidraget visade sig vara högst vid en subventioneringsnivå på3000 kr per år och anställd, och uppgick vid nämnda nivå till i genomsnitt 30 procent. Vid engrov schablonberäkning av kostnadsbesparingarna som den minskade sjukfrånvaron medför,fann vi att en subventioneringsnivå på maximalt 1000 kronor per år och anställd är olönsammedan en motsvarande nivå på 3000 kronor i bidrag per år och anställd gav ett positivtnettoresultat på nära 3000 kronor per anställd. Vi rekommenderar därför ensubventioneringsnivå på 3000 kronor per år och anställd då den nivån visade sig generera bästlönsamhet och även högst nyttjandegrad bland de anställda.
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Biomechanical analysis on the lower extremities during Tai Chi exercise. / CUHK electronic theses & dissertations collectionJanuary 2006 (has links)
Part 1. Characteristics of foot movement in Tai Chi exercise. The performance of 16 experienced Tai Chi practitioners demonstrating a whole set of 42-form Tai Chi movements were recorded with two cameras. The APAS motion analysis system was used to identify the foot supporting and stepping characteristics during the practice. Seven foot support patterns and six step directions were identified. The results revealed that compared with normal walking, Tai Chi movement had more double support and less single support total duration. The duration of each support pattern was longer and movement from one pattern to the next was slow. The duration of each step direction was short, and changes of direction were frequent. It was expected that support patterns changed slowly, and combined with various step directions, they were found to be better than those of walking in simulating the gait challenges that may be encountered in daily activities. / Part 2: The plantar pressure distribution during Tai Chi exercise. The purpose of this study is to describe and quantify the plantar pressure distribution characteristics during Tai Chi exercise and to explain the beneficial effects of Tai Chi on balance control and muscle strength as compared with normal walking. Sixteen experienced Tai Chi practitioners participated in this study. Five typical Tai Chi movements represented by stepping forward, backward, sideways, up-down, and fixing could be isolated from the whole set of 42-form Tai Chi. The pressure-time integral, ground reaction force, displacement of center of pressure during the performance of the five typical movements were recorded and analyzed by the Pedar-X insole system (Germany). Results showed that during Tai Chi movements, the loading of the first metatarsal head and the great toe were significantly greater than in other regions (p<0.05). The ground reaction forces varied between the Tai Chi movements and normal walking. Compared with normal walking, the locations of the center of pressure in the Tai Chi movements were significantly more medial and posterior at initial contact (p<0.05), and were significantly more medial and anterior at the end of contact with the ground (p<0.05). The displacements of the center of pressure were significantly wider (p<0.05) in the mediolateral direction in the forward, backward and sideways Tai Chi movements. The displacement was significantly larger (p<0.05) in the anterposterior direction in the forward movement. The plantar pressure characteristics of Tai Chi movements found in this study may be one of the important factors for Tai Chi's improvement of balance control and muscle strength. / Part 3. The duration and plantar pressure distribution during one-leg stance in Tai Chi exercise. The aim of this study is to quantify the one-leg stance duration and plantar pressure distribution during the one-leg stance in Tai Chi and to try to elaborate on its probable effects on the ability to balance on one leg. Sixteen experienced Tai Chi practitioners participated in this study. The Novel Pedar-X insole system (Germany) was used to record the plantar forces during the execution of a set of 42-form Tai Chi movements and during normal walking. The one-leg stance duration and plantar pressure distribution during the one-leg stance were analyzed. Results showed that in Tai Chi, the total duration spent in the one-leg stance was less (p<0.05), the duration of each one-leg stance was longer (p<0.01) and the medial-lateral displacement of the center of pressure was greater (p<0.05) than during normal walking. The peak pressure and pressure-time integral of the second and third metatarsal heads and the fourth and fifth metatarsal heads were significantly greater (p<0.05) than those of other plantar regions during the one-leg stance in normal walking; whereas the peak pressure and pressure-time integral of the first metatarsal head and the great toe were significantly greater (p<0.05) than those of other plantar regions during the one-leg stance in Tai Chi. The longer duration of each one-leg stance and the plantar pressure distribution characteristics during the one-leg stance in Tai Chi may be associated with an improved ability to balance on one leg. / Part 4. The muscle contraction characteristics of the lower extremities during Tai Chi exercise. The objective of this study is to examine the muscle contraction characteristics of the lower extremities during Tai Chi exercise and to explain the beneficial effect of Tai Chi on the improvement of muscle strength. Sixteen experienced Tai Chi practitioners participated in this study. Five typical Tai Chi movements, represented by stepping in forward, backward, sideways, up-down and fixing were selected. The electromyographic activity of the rectus femoris, semitendinosus, gastrocnemius, and anterior tibialis muscles were recorded by Delsys electromyography measurement system (USA) during the performance of five typical Tai Chi movements. (Abstract shortened by UMI.) / Mao Dewei. / "August 2006." / Adviser: Youlian Hong. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1598. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 102-112). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
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