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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Rozpoznávání obličeje / Face recognition

Maňkoš, Richard January 2016 (has links)
This diploma thesis deals with face recognition in digital pictures. The first part describes biometry and, shortly, characterizes biometrical methods which are the most oftenly used. In the second part is described the approach of face recognition in a picture. Specifically, it is described the method for face detection - Viola-Jones and method for face recognition - PCA, which will be implemented in Matlab. The last part, which is practical, describes the scheme for video-sequence recording, implementation of the PCA method in Matlab and discussion of the achieved results.
242

Automatické rozměření vícesvodových EKG signálů / Automatic Delineation of Multi-lead ECG Signals

Veverka, Vojtěch January 2017 (has links)
This semester thesis is focused on automated measurement of ECG signal. The theoretical part describes the rise and options ECG signal. Furthermore, the issue is staged principal components analysis, whose output is used as input signal for seasons. They describe the basic methods used in measurement to ECG signal. The practical part is designed in measurement algorithm for ECG signal that has been tested on basic CSE database. The results are discussed in the conclusion.
243

Jakost odrůd slivoní

Kožíšková, Jarmila January 2016 (has links)
In the present dissertation thesis quality of plum cultivars were investigated in three successive experiments included measurement of ethylene, CO2, ethanol, acetaldehyde, firmness of the fruits and determination of volatile aromatic compounds by SPME/GC/MS Two plum fruit varieties (Stanley and Valjevka) were stored in prepared gas mixtures (FAN: 0,6 % O2 a 1 % CO2, CA: 1 % O2 a 10 % CO2, RA: 21% O2 a 0,03 % CO2) for 70 days. In terms of the 20th, 40th and 60th day followed shelf life for 10 days at 20 °C. Firmness of the skin was different for both varieties and the softening increased in the variety Valjevka. Softening of fruits significantly decreased in FAN and CA. Skin firmness of fruits stored in normal oxygen atmosphere was lower for about 0,59 MPa (Stanley) and 0,67 MPa (Valjevka) at the end of storage. Fruits stored in CA atmosphere were firm, with unbrowning flesh and there was no browning in stem area, too. The results showed that the variety 'Valjevka' has a high capacity (1705 mg/l) to produce ethanol.There was no microbial damage in 'Stanley' stored in CA and FAN at the end of the storage, in RA were 13,19 %. The highest microbial attack was observed in Valjevka stored in RA 41,85 %. Seventy-one volatile compounds were sampled by head space SPME in two plum fruit varieties (Stanley and Valjevka). Using PCA analysis 13 compounds are sufficient for distinguishing ripening of fruits variety Stanley treated by tree storage atmospheres ((Z)-hex-3-en-1-ol, 2-methyl butan-1-ol, (Z)-3-octen-1-ol, 2-heptanol, heptanal, (Z)-3-hexenal, (E)-2-decenal, n-octanal, ethyl acetate, (E)-2-hexenyl acetate, a-terpineol, b-cyclocitral, b-ionone) and 11 compounds for 'Valjevka' (2-octanol, n-octanal, (E)-2-hexenyl acetate, b-cyclocitral, b-ionone, (Z)-3-octen-1-ol, 2-methyl-1-pentanol, (Z)-3-hexenal, n-hexanal, ethyl benzoate a butyl 2-methylbutyrate). The fruits of 13 plum cultivars were analysed at two different stages of maturity: first when they were ready for picking according to conventional commercial criteria, and again after seven days of maturation during shelf life. In the period of over-ripening SSC increased, and no differences were found in relation to the cultivar. The fruits in this period were physiologically in a phase of reduced intensity of respiration, while production of ethylene increased and was associated with the earliness of the cultivar. Cultivars with a short vegetation period produce more ethylene while late-maturing cultivars have a low potential for ethylene production. Based on post-harvest changes in the tested quality factors, the late-ripening plum cultivars (cv.) Jojo, Topend, President, Tophit and Elena have higher storage potential. A high significant negative correlation was detected between levels of skin firmness and ethylene production. 69 of volatiles were determined by GC/MS/SPME. There are eight compounds (oct-1-en-3-ol, p-menth-1-en-4-ol-R, n-hexan-1-ol, n-pentan-1-ol, ethylhexan-1-ol, g-nonanolaktone, g-kaprolaktone and g-oktalaktone) which taken together can be used to distinguished the two different stages of maturity. The fruits of cv. 'Tophit' were untreated or treated with 1-MCP for 24 h at 20 °C and then kept at 1 °C for 50 days in the atmosphere CA (2 % O2 a 7 % CO2) and RA. Plums were evaluated after 10, 30, 50 days of storage at 1 °C followed by shelf life storage for 7 days. The effect of cold and 1-MCP treatment resulted in significant inhibition of ethylene production, respiration rate and retention of flesh firmness after transfer to room temperature. Sixty-four volatile compounds were sampled by head space SPME and identified by GC-MS, from which (E)-2-hexenal, (Z)-hex-3-en-1-ol, butyl-2-methylbutyrate and limonen were significant.
244

Evaluation of Homogeneity in Drug Seizures Using Near-Infrared (NIR) Hyperspectral Imaging and Principal Component Analysis (PCA)

Strindlund, Olle January 2020 (has links)
The selection of a representative sample is a delicate problem when drug seizures comprised of large number of units arrive at the Swedish National Forensic Centre (NFC). If deviating objects in the selected sample size are found, additional analyzes are required to investigate how representative the results are for the entire population. This generates further pressure on operational analysis flow. With the goal to provide a tool which forensic scientists at NFC can base their assessment of the representative nature of the selected sampling of large drug seizures on, this project investigated the possibilities of evaluating the level of homogeneity in drug seizures using near-infrared (NIR) hyperspectral imaging along with principal component analysis (PCA). A total of 27 sample groups (homogeneous, heterogeneous and seized sample groups) were analyzed and different predictive models were developed. The models were either based on quantifying the variation in NIR spectra or in PCA scores plots. It was shown that in the spectral range of 1300-2000 nm, using a pre-processing combination of area normalization, quadratic (second polynomial) detrending and mean centering, promising predictive abilities of the models in their evaluation of the level of homogeneity in drug seizures were achieved. A model where the approximated signal-dependent variation was related to the quotient of significant and noise explained variance given by PCA indicated most promising predictive abilities when quantifying the variation in NIR spectra. Similarly, a model where a rectangular area, defined by the maximum distances along PC1 and PC2, was related to the cumulative explained variance of the two PCs showed most promising predictive abilities when quantifying the variation in PCA scores plots. Different zones for which within sample groups are expected to appear based upon their degree of homogeneity could be established for both models. The two models differed in sensitivity. However, more comprehensive studies are required to evaluate the models applicability from an operational point-of-view.
245

A Study on the Market and Movements of Cryptocurrencies

Isaksson, William January 2022 (has links)
There has been much debate among investors on the benefits cryptocurrencies can have for portfolios and how their prices moves in the market. It is not difficult to see that cryptocurrencies are very volatile, yet that does not prevent investors from pouring tons of money in crypto-investments that either generate huge returns or catastrophic losses. One of the main challenges with is cryptocurrenciesis determining how they move with the rest of the market with assets such as stocks. The objective of this thesis was to investigate whether or not crypto provides some diversification benefit and if individual cryptocurrencies move in the same manner with respect to eachother. Of special interest was if there is a relationship between the cryptocurrency market and the stock market. The cryptocurrencies chosen for this project were compared mostly to the stocks in the, very information technology-sector focused, Nasdaq 100 index along with a few other assets. This thesis was written in cooperation with Origin Group AB, an Umeå based startup firm specializing in development of cryptocurrency-related technologies, most notably blockchain. All data used comes from publicly available sources and mostly include prices for cryptocurrencies and stocks from which the daily and weekly returns were calculated. The main methods used for this thesis was four different portfolio strategies with different combinations of assets, Style analysis, and principal component analysis. The portfolio strategies showed some promise with varying tradeoffs between diversification and Sharpe-ratio but the results are a bit questionable due to the short investment period. The principal component analysis showed that the cryptocurrency price data is very noise and the currencies moves pretty much in unison in contrast to the industry sector divided Nasdaq 100, which seem to have a few more distinct directions of movement. The Style-analysis’ inconclusive results show signs of a very noisy dataset and that there may not be a clear linear relationship between conventional asset returns and those of crypto.
246

Localized Anthropogenic and Geogenic Groundwater Contamination in the Structurally Complex Carbonate-Hosted East Tintic Mining District, Eureka, UT, USA

Cordner, Cameron Patrick 21 June 2021 (has links)
Legacy mining areas throughout the world contain widespread contaminated surface and groundwater from both anthropogenic and geogenic sources. Abandoned mine waste can contribute harmful solutes to groundwater and surface water, as metals mobilize through oxidation of sulfide minerals. Geogenic contaminant sources, such as geothermal water and mineralization, may also contribute to groundwater pollution in mining areas. To investigate the relationship between various groundwater contamination sources in legacy mining areas we sampled ~30 cold springs in the East Tintic Mountains of Utah and 8 regional hot springs as a proxy for geothermal water during fall 2019 and spring/summer 2020. Water chemistry data were analyzed using a Principal Components Analysis (PCA), revealing two distinct groundwater systems for hot and cold springs with no apparent mixing between the two. Only one cold spring was clearly enriched in multiple metals (Al, Mn, Co, Ni) relative to other springs but was not located proximal to any significant mining waste rock piles. 87Sr/86Sr ratios were analyzed in a subset of samples to identify flowpaths through carbonate or volcanic rocks. Only two springs had 87Sr/86Sr ratios characteristic of the Eocene and Oligocene volcanic rocks that dominate the surface of the study area (0.707 - 0.708), with all others having ratios indicative of underlying Paleozoic carbonate rocks (0.708 -0.710). Groundwater flow through carbonate rocks is dominated by faults and fractures, with faults appearing to act as barriers rather than conduits to flow. Faults create groundwater compartmentalization within the carbonate rock that isolates water contaminated by mining waste, while the carbonate rocks neutralize acid mine drainage. Groundwater compartmentalization explains the lack of widespread contamination despite the presence of large mining waste piles throughout the area. Mixing between geothermal and shallow groundwater may be the source of high Li, B, and SO42- concentrations in a limited number of springs. Our results suggest that contamination from mining waste is highly localized and that that waters discharging from mining areas overlying faulted carbonate rocks may be less contaminated than previously thought. This study has implications for understanding groundwater contamination dynamics in semi-arid regions impacted by mining.
247

Inducerad infiltration och Vyredox - Studie av Tranås nya vattentäkt. / Induced infiltration and Vyredox. A study of Trånas new water supply.

Regazzoni, Marco January 2011 (has links)
Målet med projektet var att beskriva de biogeokemiska processer som påverkar grundvattenkvaliteten i Tranås nya vattentäkt. Grundvattenbildningen på platsen sker framför allt genom inducerad infiltration av vatten från sjön Sommen. I syfte att avskilja järn och mangan pumpas grundvattnet upp, syresätts och injekteras sedan i brunnar för att skapa en oxiderande grundvattenmiljö. Metoden kallas Vyredox. Med en 15 månader lång provtagningsserie och automatiskt registrerade processvärden och driftdata från anläggningen som underlag görs i rapporten bedömningar om trender, säsongsmässiga variationer och samband mellan driftsituation och kvalitet på utgående vatten. Dessutom görs en provtagning på flera platser runt anläggningen för att undersöka rumsliga variationer av grundvattnets sammansättning. Den statistiska metoden principalkomponentanalys har använts i syfte att utreda vattnets ursprung. Arbetet resulterade i en beskrivning av vattenkvalitetens utveckling under vattentäktens första år i drift, och en diskussion om framtida scenarion. En slutsats är att en form av mark/vatten-kemisk jämvikt uppstår i akviferen ungefär 6 månader efter det att den nya anläggningen började köras. En annan slutsats är att manganhalten kommer minska i framtiden. Provtagningen visar att utgående råvatten i högre grad än vad som förutspåtts innehåller vatten med annat ursprung än sjön. Samband mellan driftsituation och vattenkvalitet förtydligas och resultaten pekar mot att det utgående vattnets sammansättning påverkas av de förändrade flödesvägar och avsänkningar kring uttagsbrunnarna som uppstår vid olika driftfall.
248

Using machine learning to predict power deviations at Forsmark

Björn, Albin January 2021 (has links)
The power output at the Forsmark nuclear power plant sometimes deviates from the expected value. The causes of these deviations are sometimes known and sometimes unknown. Three types of machine learning methods (k-nearest neighbors, support vector machines and linear regression) were trained to predict whether or not the power deviation would be outside an expected interval. The data used to train the models was gathered from points in the power production process and the data signals consisted mostly of temperatures, pressures and flows. A large part of the project was dedicated to preparing the data before using it to train the models. Temperature signals were shown to be the best predictors of deviation in power, followed by pressure and flow. The model type that performed the best was k-nearest neighbors, followed by support vector machines and linear regression. Principal component analysis was performed to reduce the size of the training datasets and was found to perform equally well in the prediction task as when principal component analysis was not used.
249

Skumproblematik i avloppsreningen vid Holmen Bravikens pappersbruk : Orsak och lösningsförslag

Björklund, Isabelle January 2021 (has links)
The treatment of industrial wastewater is an important measure to prohibit eutrophication and intoxication of lakes and oceans. Major industries often have location-basedwastewater treatment and to avoid undesired effluents it is essential to make it robust.The integrated pulp- and papermill Braviken is experiencing a malfunction in their wastewater treatment plant. The wastewater treatment at Braviken is divided into multiplestages where one of them is biological treatment by an activated sludge process. Thisstage is modeled as a Low Sludge Production (LSP) where an aerated selector helps tofaciliate the microbial growth of the wastewater. The microorganisms digest wastewaterpollutants in this step only to be consumed by micro-animals in the next step, the activesludge basin. During recent winters, Braviken have experienced a problematic sludge bulking in the selector. During the most problematic episodes, manual removal of the foamhave been needed with an excavator. The aim of this study have been to explain why thefoaming occurs and present an action proposal to prevent the bulking.To answer the questions at issue, previously measured monitoring data from the foamingepisodes have been analysed. A principal component analysis was performed, using monitoring data from each problematic winter and compared to the non-bulking referencewinter of 2017-2018. Additional sampling was collected and analysed to investigate theconnection between process management and its influence of the physical characteristicsof the wastewater.When the investigation had been accomplished it was concluded that the waste waterbulking was caused by a low nitrogen and phosphorus concentration combined with a highorganic carbon influent. This caused a reduction in the metabolism of the microorganisms,resulting in a increased colloidal surface charge and high extracellular polymeric substance(EPS)-content. The reason for the problem occuring during winters can be explained bya generally low water temperature in the selector and a physical difference in the woodcompared to summer wood. When performing microbial studies of the wastewater itoccured to be a presence of filamentous bacteria in both the selector and the previousleveling basin. This presence was concluded to be a result of reduced aeration and anincreased hydraulic retention time during the winter 2020-2021.To avoid future problematic foaming in the activated sludge process, an increased dosage ofnitrogen and phosphorus is recommended. The result show that a increased concentrationof phosphorus and nitrogen in relation to influent COD had a reducing effect of thecolloidal surface charge in the wastewater.
250

Évaluation de la qualité de l’eau du bassin supérieur de la rivière du Litani, Liban : approche hydrogéochimique / Evaluation of the quality of the water of upper basin of the Litani River, Lebanon : Approaches hydrogeochemical

Moussa Haidar, Chaden 22 October 2014 (has links)
A la quantité limitée de l’eau disponible au Liban, vient s’ajouter un nouveau problème, la dégradation de la qualité des eaux superficielles menacées continuellement par la pollution et la salinisation. Les utilisations agricoles et industrielles et l’augmentation de la population génèrent des pollutions des cours d'eau qui posent des problèmes environnementaux et sanitaires. Afin de limiter et d'anticiper ces pollutions, il est nécessaire de disposer de méthodes d'évaluation des effets des systèmes de culture sur la pollution des eaux de rivière. Pour cela, nous avons sélectionné la rivière Litani qui est la plus longue rivière et la plus importante au Liban, sur laquelle deux dispositifs de suivis ont été mis en œuvre entre 2010 et 2013. En raison de l'absence de données sur la qualité de l'eau, nous proposons dans cette étude de vérifier les paramètres de pollution du bassin supérieur qui constitue la majorité de surface du bassin. L’objectif de ce projet est de réaliser une étude prospective sur la qualité de la ressource en eau du bassin supérieur du Litani en incluant le lac de Qarraoun, de comprendre la relation entre la recharge et la consommation d’eau et, si pertinent, de proposer des solutions pour une meilleure gestion des eaux polluées. L'étude porte sur l'interprétation des sources de pollution en mesurant de nombreux paramètres physicochimiques (pH, T °, TDS, Ec), chimiques (Na, Ca2, Mg2, Cl-, SO2-4, NH3, NO-3, PO2-4, K, DBO5 et DCO), les métaux lourds (Fe, Ni, Zn, Cu, Cr, Al, Ba, Pb, Mn) et des paramètres microbiologiques de l'eau et les sédiments de la partie supérieure du bassin Litani et dans le lac. Des échantillons ont été prélevés au cours des trois saisons d’hiver (Février), du printemps (mai) et d’été (Septembre) en 2010-2013. Les analyses microbiologiques et physico-chimiques sont effectuées en conformité avec les méthodes standards européennes et méthode standard (OMS). Des méthodes statistiques multi-variées (analyse hiérarchique de la concentration : HAC, et de l'analyse en composantes principales : PCA) et la corrélation de Pearson ont ensuite été appliquées pour déterminer l'influence des polluants dans le lac et la rivière / Lebanon has abundant water, but its river is polluted. The Litani River is the largest one, draining from north to south in the central core of the country (Bekaa Valley) before turning west to the sea. It crosses down a rather deep valley and passes by several urban agglomerations and industrial zones, which use its water as a discharge system of their waste. This study shows the impact of the anthropic activities on the water quality of this river. Physical (pH, T°, TDS, Ec), chemical (Na+, Ca2+, Mg2+, Cl?, SO2?4, NH3+, NO?3, PO2?4, K+, BOD5 and COD), heavy metals (Fe, Ni, Zn, Cu, Cr, Al, Ba, Pb, Mn) and microbiological parameters of water quality assessment and sediment for the Upper Litani River Basin was performed. They were investigated during three seasons of rainy, mid-rainy spring and wet season, during the years 2010-2013 to determine correlation between chosen chemical water parameters and bottom sediments parameters. Microbiological and physico-chemical analyses are performed in accordance International methods (e.g. European Standard Methods, WHO). In addition, Multivariate statistical methods (Hierarchical Clustering Analysis: HCA, and Principal Component Analysis: PCA) and Pearson’s correlation were applied to figure out the influence of pollutants disposal in the Lake and the River as well. Sediments were characterized by a set of chemical analyses, cations exchange capacity, mineralogical X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR). To assess metal contamination in sediments, Consensus-Based Sediment Quality Guidelines of Wisconsin (CBSQG) were applied. The metals contamination in the sediments was also evaluated by contamination factor (Cf), and the results showed that the effect of seasonal variations was important in the Upper Litani River Basin and the degree of contamination was increased in dry season. All the sites are characterized by moderate to highly microbial polluted range and some site was highly polluted and contaminated

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