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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.
81

Time-lapse Analysis of Borehole and Surface Seismic Data, and Reservoir Characterization of the Ketzin CO2 Storage Site, Germany

Yang, Can January 2012 (has links)
The CO2SINK (and CO2MAN) project is the first onshore CO2 storage project in Europe. The research site is located near the town of Ketzin, close to Potsdam in Germany. Injection started in June 2008, with a planned injection target of 100,000 tonnes of CO2. In February 2011, around 45, 000 tons of CO2 had been injected into the saline aquifer at an approximate depth of 630 m. This thesis focuses on time-lapse analysis of borehole seismic data, surface seismic data and reservoir characterization at the Ketzin site. Baseline Moving Source Profiling (MSP) data were acquired in the borehole Ketzin 202/2007 (OW2), along seven lines in 2007. The zero-offset Vertical Seismic Profile (VSP) data were acquired in the same borehole. The main objective of the VSP and MSP survey was to generate high-resolution seismic images around the borehole. After modeling and data processing, the sandy layers within the Stuttgart Formation can potentially be imaged in the VSP and MSP data whereas reflections from these layers are not as clearly observed in the 3D surface seismic data. 2D and pseudo-3D time-lapse seismic surveys were conducted at the Ketzin site. Interpretation of 2D baseline and repeat stacks shows that no CO2 leakage related time lapse signature is observable where the 2D lines allow monitoring of the reservoir. This is consistent with the time-lapse results of the 3D surveys showing an increase in reflection amplitude just centered around the injection well. The results from the pseudo-3D surveys are also consistent with the 3D seismic time-lapse studies and show that the sparse pseudo-3D geometry can be used to qualitatively map the CO2 in the reservoir with significantly less effect than the full 3D surveying. The 2nd pseudo-3D repeat survey indicates preferential migration of the CO2 to the west. There are no indications of migration into the caprock on either of the repeat surveys. Amplitude Versus Offset (AVO) analysis was performed on both 2D and 3D repeat surveys. A Class 3 AVO anomaly is clearly observed on the 3D repeat data and matches the synthetic modeling well. No AVO anomaly was observed on the 2D repeat data, which was anticipated, but the result shows signs of a pressure response at the reservoir level in the data. Reflection coefficients were calculated using surface seismic data (3D and pseudo-3D) at the site. Pre-injection calculations agree well with calculations from logging data. Post-injection calculations are in general agreement with the seismic modeling, but generally show higher amplitudes than those expected. The full 3D data show a better image of the reflection coefficients before and after injection than the pseudo-3D data and can potentially be used to make quantitative calculations of CO2 volumes. The pseudo-3D data only provide qualitative information.
82

Entwicklung von Verfahren zur Bestimmung räumlich-zeitlich hochaufgelöster Bewegungsvektorfelder an Gletschern aus monoskopischen Bildsequenzen / Development of methods for the determination of spatio-temporal high-resolution motion vector fields at glaciers based on monoscopic image sequences

Schwalbe, Ellen 04 June 2013 (has links) (PDF)
Die vorliegende Arbeit beschäftigt sich mit der Bestimmung von räumlich und zeitlich hochaufgelösten Bewegungsvektorfeldern von Gletschern aus monokularen Bildsequenzen. Diese stellen eine wertvolle Grundlage für glaziologische Analysen des Bewegungsverhaltens von Gletschern dar. Im Rahmen der Arbeit wurden Bildsequenzmessungen an fünf schnellfließenden Gletschern im Bereich der Diskobucht in Westgrönland durchgeführt. Insbesondere erfolgte die Aufnahme von Bildsequenzen und multi-temporalen Laserscannerdaten am Jakobshavn Isbræ, einem der schnellsten und produktivsten Gletscher Grönlands. Diese Messungen bilden die Datengrundlage der Arbeit. Es werden Messkonzepte zur Aufnahme der entsprechenden Bildsequenzen und multi-temporalen Laserscans bereitgestellt sowie Methoden entwickelt, um die Auswertung dieser Daten nach dem Prinzip der monoskopischen Bildsequenzanalyse zu ermöglichen. Die Bildsequenzen und multi-temporalen Laserscans werden von einem festen Standpunkt aus aufgenommen. Die Ableitung von Bewegungsvektorfeldern erfolgt dann durch eine automatische Zuordnung von Grauwertmustern in den Bildsequenzen bzw. durch die Zuordnung von 3D-Punktmustern in den multi-temporalen Laserscannerdaten. Bestehende Punktzuordnungsmethoden werden einerseits an die besonderen Eigenschaften der Gletscherdaten angepasst, andererseits werden geeignete Methoden zur Lösung von Detailproblemen neu entwickelt. Die Methodik der Bildsequenzanalyse wird dabei vor allem hinsichtlich ihrer Robustheit – beispielsweise gegenüber durch Schattenwurf verursachten Störungen im Bild – optimiert und es werden Bewegungseffekte in den Bildsequenzen korrigiert, die durch die Eigenbewegung der Kamera verursacht werden. Bei der Entwicklung der Methodik zur Analyse multitemporaler Laserscannerdaten werden vor allem Effekte berücksichtigt, die durch das sequenzielle Aufnahmeprinzip eines Scanners auftreten. Auf Basis der entwickelten und implementierten Methodik erfolgt die Auswertung der aufgenommenen Bildsequenzen und multi-temporalen Laserscans. Das Ergebnis der monoskopischen Bildsequenzauswertung ist ein dichtes Raster an Bewegungskurven für jede Bildsequenz. Die einzelnen Translationen der Bewegungskurven können mit einer Genauigkeit von einigen Zentimetern bis zu einem Dezimeter bestimmt werden. Die Auswertung der Laserscannerdaten liefert räumlich hochaufgelöste digitale Geländemodelle der Gletscheroberfläche sowie ein dichtes Raster von 3D-Bewegungsvektoren, deren Genauigkeit im Dezimeterbereich liegt. Anhand von Beispielen wird gezeigt, dass sich die aus monokularen Bildsequenzen abgeleiteten Bewegungsvektorfelder zur Bestimmung frontnaher Geschwindigkeitsfelder mit hoher räumlicher Auflösung, zur Ableitung der Lage und der Migration der Aufsetzlinie aus gezeiteninduzierten Vertikalbewegungen sowie zur Untersuchung des Geschwindigkeitsverhalten von Gletschern bei Kalbungsereignissen eignen. Aus den Laserscannerdaten können hochaufgelöste digitale Geländemodelle zur Dokumentation von Fronthöhen und Gletscherstrukturen abgeleitet werden, zudem eignen sie sich zur Bestimmung von Geschwindigkeitsfeldern, die eine sehr hohe räumliche Auflösung besitzen. / This research aims to determine the motion vector fields of glaciers with high spatial and temporal resolution. These vector fields can be derived from monocular image sequences and are a valuable data source for glaciological analysis of the motion behaviour of glaciers. Image sequence measurements have been conducted at five fast-flowing glaciers in the Disko Bay region in western Greenland. Especially at the Jakobshavn Isbræ – one of the fastest and most productive glaciers in Greenland – numerous image sequences have been recorded, as well as multi-temporal laser scanner data sets. These measurements provide the basic data sets for this thesis. The measurement concepts for the acquisition of image sequences and multi-temporal laser scans are presented, and procedures for the processing of the recorded data are developed, based on the principle of monoscopic image sequence analysis. Both the image sequences and multi-temporal laser scans are acquired statically. Motion vector fields can be derived by applying automatic co-registration methods on grey value patterns in the image sequences and on 3D point patterns in the laser scanner datasets respectively. Thus, standard matching techniques have been adapted to the special characteristics of the glacier data, and suitable methods that solve detail problems have been developed in addition. The method of the image sequence analysis has been optimised with respect to its robustness against errors caused by moving shadows. Furthermore, motion effects caused by small instabilities in the camera setup have been corrected. Regarding the analysis of multi-temporal laser scanner data, effects that occur because of the sequential acquisition principle of a laser scanner must also be considered. Based on the developed method, the image sequences and multi temporal laser scans have been processed. The result of the monoscopic image sequence analysis is a dense raster of trajectories for each image sequence. Each translation component from these trajectories can be determined with an accuracy of some centimeters up to one decimetre. The processing of the laser scanner data provides digital surface models of the glacier with high spatial resolution, and a dense raster of 3D motion vectors with accuracy in the range of decimetres. Specific examples show that motion vector fields derived from monocular image sequences can be used for the determination of high resolution velocity fields of glaciers, for the determination of the position and migration of the grounding line and for the investigation of a glacier’s motion behaviour during calving events. From the multi-temporal laser scanner data, velocity fields with high spatial resolution can be derived as well as digital surface models from single scans that document glacier front heights and glacier structures.
83

Design and Deployment of a Controlled Source EM Instrument on the NEPTUNE Observatory for Long-term Monitoring of Methane Hydrate Deposits

Mir, Reza 31 August 2011 (has links)
Hydrocarbon deposits in the form of petroleum, natural gas, and natural gas hydrates occur offshore worldwide. Electromagnetic methods that measure the electrical resistivity of sediments can be used to map, assess, and monitor these resistive targets. In particular, quantitative assessment of hydrate content in marine deposits, which form within the upper few hundred meters of seafloor, is greatly facilitated by complementing conventional seismic methods with EM data. The North-East Pacific Time-series Undersea Network Experiment (NEPTUNE) is an underwater marine observatory that provides power and network connection to a host of instruments installed on the seafloor on the Cascadia Margin offshore Vancouver Island. The observatory’s aim is to provide a platform for very long-term studies in which access to data is available on a continuous basis. For this thesis project, a transient dipole-dipole time-domain EM system was constructed and deployed on the NEPTUNE network with the goal of long-term monitoring of a well-studied hydrate deposit in the area. The instrument includes a source transmitter of electrical current and individual receivers to measure small electric field variations. The instrument is powered by the NEPTUNE observatory and data can be collected remotely by connecting to the instrument through the web. Data collected so far from the instrument are consistent with a resistive structure. The best fitting model from 1D inversion is a 36 ± 3 m thick layer of 5.3 ± 0.3 Ωm resistivity, overlaying a less resistive 0.7 ± 0.1 Ωm halfspace. Average hydrate concentration, deduced with the aid of ODP-889 well-log derived Archie’s parameters, is approximately 72% of pore space in the resistive layer, consistent with the very high concentration of gas hydrates (~80%) recovered from seafloor cores. The weekly collection of data from the instrument shows that the resistive structure has changed little since monitoring began in October of 2010.
84

Design and Deployment of a Controlled Source EM Instrument on the NEPTUNE Observatory for Long-term Monitoring of Methane Hydrate Deposits

Mir, Reza 31 August 2011 (has links)
Hydrocarbon deposits in the form of petroleum, natural gas, and natural gas hydrates occur offshore worldwide. Electromagnetic methods that measure the electrical resistivity of sediments can be used to map, assess, and monitor these resistive targets. In particular, quantitative assessment of hydrate content in marine deposits, which form within the upper few hundred meters of seafloor, is greatly facilitated by complementing conventional seismic methods with EM data. The North-East Pacific Time-series Undersea Network Experiment (NEPTUNE) is an underwater marine observatory that provides power and network connection to a host of instruments installed on the seafloor on the Cascadia Margin offshore Vancouver Island. The observatory’s aim is to provide a platform for very long-term studies in which access to data is available on a continuous basis. For this thesis project, a transient dipole-dipole time-domain EM system was constructed and deployed on the NEPTUNE network with the goal of long-term monitoring of a well-studied hydrate deposit in the area. The instrument includes a source transmitter of electrical current and individual receivers to measure small electric field variations. The instrument is powered by the NEPTUNE observatory and data can be collected remotely by connecting to the instrument through the web. Data collected so far from the instrument are consistent with a resistive structure. The best fitting model from 1D inversion is a 36 ± 3 m thick layer of 5.3 ± 0.3 Ωm resistivity, overlaying a less resistive 0.7 ± 0.1 Ωm halfspace. Average hydrate concentration, deduced with the aid of ODP-889 well-log derived Archie’s parameters, is approximately 72% of pore space in the resistive layer, consistent with the very high concentration of gas hydrates (~80%) recovered from seafloor cores. The weekly collection of data from the instrument shows that the resistive structure has changed little since monitoring began in October of 2010.
85

脫退率模型之建構與應用―台灣壽險資料 / Establishment and Application of Lapse Rate Model

彭文慧, Peng,Wen Hui Unknown Date (has links)
本研究以保險事業發展中心之資料分析各種不同因子如年度、性別、保額、有無體檢、保費繳別、保單年度及利差、利率等對脫退率之影響,並將其中較具顯著影響的因子納入脫退率模型之建立,期望能藉此模型準確估計台灣壽險公司生死合險、終身壽險以及定期壽險之脫退率,進而幫助壽險公司之財務規劃。 自本研究之分析發現其中最具影響力之因子為保單生效後之保單年度,因此以此為主軸建立脫退率模型,接著,亦考量利差以及利率所呈現的趨勢於其中分別建立保單年度利差模型以及保單年度利率模型,此外,更完整考量本研究中脫退率相關因素,以羅吉斯迴歸方法建立模型。最後將此四種模型應用於壽險公司準備金之提存,以生死合險為例模擬公司現金流量,發現準備金之分配如同 Tsai et al.(2002)受利率風險影響甚鉅,而加入本研究所建立之四種脫退率模型模擬後,反而減少了公司未來所須面臨的利率風險,其中又以保單年度模型影響最大,而第四種脫退率模型不同於Tsai et al.根據台灣壽險經驗加入所有具影響之因素,其模擬結果介於保單年度模型以及保單年度利率模型間,可發現考量因素之不同對脫退率影響甚鉅,繼而影響準備金之提存。 / In this article, we focus on the causes and the features of lapse rate including year, sex, size, underwriting method, premium payment mode, policy year, interest rate and interest rate difference by collecting and analyzing the empirical data of endowment, whole life insurance and term life insurance in Taiwan from Taiwan Insurance Institute. Then we take factors that have effect with lapse rate into account to establish model, and we hope to accurately estimate the lapse rate of endowment, whole life insurance and term life insurance in Taiwan by these models, and assist the life insurance companies’ financial decision making. After analyzing, we find the most effective factor of this study is the policy year, which means the year after issuing, so we take this one as our primary consideration of our lapse rate model. Then we add the interest rate difference and interest rate in the further two models. Beside this, we further consider the important factors in the part of analysis and put it in the fourth model by using Logistic Regression Model. Finally, we apply these four models to the policy reserve of life insurance company by taking endowment policy as an example simulating the cash flow. We find that the results was same as Tsai et al. (2002) that distribution of policy reserve is strongly affected by interest rate risk, but can decrease interest rate risk the company have to face in the future by adding our lapse rate models, especially the policy year model, and the fourth lapse rate model which count into most factors was not the same as Tsai et al. producing result between policy year model and the policy- interest rate model. From the results of all the lapse rate model. We can know that considering different factors in the model will bring such distinct contribution amount of reserve for life insurance company.
86

Time-lapse (4D) seismic interpretation methodologies based on kriging analysis : application to the Senlac (onshoreCanada) and Marlim ( offshore Brazil) heavy oilfields / Méthodologies d'Interprétation par Analyse Krigeante des données sismiques 4D réservoir. Applications aux huiles lourdes de Senlac (Canada) et au champ Marlim (Brésil)

Borges De Salles Abreu, Carlos Eduardo 07 March 2008 (has links)
L’objectif de la thèse est de développer une méthodologie permettant d’obtenir une interprétation quantitative des données de sismique répétée (sismique 4D). Une étape essentielle consiste à évaluer la répétitivité des données, puis à filtrer les bruits indésirables, qui peuvent masquer ou détériorer la signature 4D. Une méthodologie basée sur des outils géostatistiques a été développée. Deux fenêtres temporelles des cubes sismiques étudiés sont choisies, l’une au-dessus du réservoir - où aucun effet 4D n’est attendu - et l’autre incluant le réservoir. Une analyse statistique et variographique conduite sur ces différentes fenêtres permet de proposer une décomposition des variogrammes en structures communes ou indépendantes, qui sont ensuite interprétées en termes de bruit, de signature géologique ou 4D. Les structures interprétées comme indépendantes de la géologie ou de la production sont ensuite filtrées à l’aide de la technique du krigeage factoriel proposée par Matheron en 1982. La méthodologie a été testée sur deux cas réels. Le premier concerne un champ d’huiles lourdes canadien, sur lequel trois campagnes sismiques ont été enregistrées, avant et pendant la production obtenue à l’aide d’injection de vapeur. Le bruit interprété comme tel sur les 3 campagnes a été filtré à l’aide la méthode décrite plus haut ; une analyse en termes de faciès sismiques non supervisée a ensuite été conduite sur les données brutes et filtrées afin d’évaluer l’intérêt du filtrage. Finalement, une interprétation des décalages en temps observés entre campagnes a été proposée. Le deuxième cas réel concerne un champ turbiditique profond dans l’offshore du Brésil, sur lequel deux campagnes sismiques 3D ont été acquises, avant et après le début de la production obtenue par injection d’eau. Le bruit présent sur les deux campagnes a été filtré à l’aide de la technique du krigeage factoriel, et la qualité de ce filtrage a pu être évaluée par comparaison avec d’autres techniques couramment utilisées / This thesis research aims at investigating seismic interpretation methodologies and techniques that will help on better characterizing time-lapse, or 4D, seismic signatures. These techniques and methodologies are used to evaluate the time-lapse repeatability and then to filter out undesirable artefacts that are non-related to the production, while enhancing the 4D signature. To achieve these goals, a methodology based on geostatistical tools, was developed. Typically, at least two time-interval windows are considered: one above and the other comprising the reservoir of interest. A statistical and variographic analysis, conducted on both windows and on all surveys, leads to an interpretation step where common or independent structures – in the variographic sense- can be pointed out. The structures interpreted as not related to the geology or to the production mechanism are filtered from the data by a multivariate factorial cokriging technique, based on the concept of Kriging Analysis developed by Matheron in 1982. Two real case time-lapse studies were used to test the methodology. The first case is a Canadian onshore heavy oil reservoir submitted to steam injection, where three different time-lapse surveys were shot to monitor the steam-chamber evolution. The noise present in the three surveys was first filtered using the technique described above; next, an unsupervised seismic facies analysis was conducted on both raw and filtered data in order to evaluate the filtering technique, and finally an interpretation, in terms of reservoir properties changes, of the time-shit observed between the campaigns was proposed. In the second case, the seismic data was acquired on a deepwater turbiditic oilfield from Brazil at two different times of reservoir life, before and after production and water injection. The two seismic surveys were filtered using the factorial kriging technique; the quality of the filtering was, in this case, evaluated by comparison with more common techniques
87

La caducidad de la responsabilidad civil de los directores de una sociedad anónima

Tambini-Monge, Ruth-Natalia, Tambini-Monge, Ruth-Natalia January 2016 (has links)
Trabajo de investigación
88

Novel computer vision algorithms for automated cell event detection and analysis

Hur, In Ae 01 May 2012 (has links)
Live cell imaging is the study of living cells using microscope images and is used by biomedical researchers to provide a novel way to analyze biological functions through cell behavior and motion studies. Cell events are seen as morphological changes in image sequences, and their analysis has great potential for the study of normal/abnormal phenotypes and the effectiveness of drugs. While current quantitative cell analysis typically focuses on measuring whole populations of cells, we need to be able to recognize cell events at the single cell level, identify these events automatically, and analyze these events over time. For this reason, we developed and evaluated several novel automatic single cell event detection and analysis methods based on a detailed knowledge of the cell cycle and other cell event characteristics. The first method detects significant events within the temporal sequence using a machine learning method to use features derived from segmented cell images. We used a Neural Network (NN) algorithm to classify cell events to pre-defined categories. The second and third methods apply statistical and econometric techniques originally developed for time-series analysis of financial markets to facilitate the identification of cell entry into mitosis. We developed graph trend analysis and paired graph analysis methods from trend analysis and pairs trading to determine significant data points in cell feature data. The final method determines the position of cells in order to associate daughter cells with their parent cells after mitosis using Kalman filter techniques. By using the Kalman filter approach, we estimated future cell border centroid positions and successfully associated daughter cells with their parent cells after mitosis. In this study, the performance of these novel computer vision algorithms for automatic cell event detection and analysis were evaluated and verified by applying models to different image sequences from the Large Scale Digital Cell Analysis System (LSDCAS). The results show that the approaches developed can yield significant improvements over existing algorithms.
89

Automatizovaný posun pro pořizování časosběrných snímků / Automated device for shift time-lapse capture

Trenz, Tomáš January 2018 (has links)
Automatic slider for time lapse photography and the creation of a functional sample is described in this diploma work. The individual components and the control program itself are analyzed.
90

Evaluating the use of photography for monitoring feeding habits of common murre (Uria aalge)

Rydevik, Elin January 2021 (has links)
Seabirds are often used as indicator species for changes in marine ecosystems due to the species visibility and sensitivity to changing conditions, such as changes in prey abundance. They often reside in habitats affected by anthropogenic impacts such as large-scale fisheries and pollution. Understanding the connection between seabirds and their surrounding environment can give us important insight about the ecology of the ocean and how anthropogenic pressures affects it. Studying feeding habits, and foraging behavior especially, is useful for understanding seabird´s responses to changing environments. Feeding studies are commonly used in seabird monitoring and requires a lot of time and resources. Monitoring of seabirds are also logistically challenging, and the risk of disturbing bird colonies must be considered. It can be especially complicated when studying cliff nesting seabirds such as the common murre, Uria aalge, the study species for this thesis. Photography as a method for monitoring seabirds may limit the need of people on site, hence minimize disturbance and save time and resources. This study provides insight in whether it is a viable option to use photography instead of on-site field studies when monitoring sea birds. This was accomplished by installing cameras and monitor a feeding study at Stora Karlsö, Sweden, parallel with performing the usual monitoring in the field. This thesis makes it clear that a camera study very well could replace the field study without any larger concerns, although, improvements need to be considered if the study is to maintain a high quality and for results to be reliable.

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