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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.
51

Meso- und mikroskalige Untersuchungen der Landoberflächentemperaturen von Berlin

Weber, Nadine 05 August 2009 (has links)
Städtische Gebiete unterscheiden sich von Flächen mit ruraler Prägung, im Ergebnis sind sie stark modifiziert bezüglich ihrer Strahlungs- und Energiebilanz. In der vorliegenden Arbeit werden die Oberflächentemperaturen der Metropole Berlin im Mesomaßstab, unter Verwendung von Satellitenaufnahmen der ASTER- und Landsat-5- und 7-Sensoren untersucht sowie durch zusätzliche Messungen mit einer Thermalbildkamera über einen Zeitraum von 17 Monaten im Mikromaßstab erweitert. Diese Daten kombiniert mit GIS-basierten Informationen über die Landnutzungs- und Strukturtypen werden für die Analyse der räumlichen und zeitlichen Verteilung der Oberflächentemperaturen genutzt ebenso wie zur Ermittlung funktioneller Beziehungen zwischen dem thermischen Verhalten der Oberflächen und der zugehörigen Stadtstruktur. Bei der Auswertung geht es vorrangig um physikalische Prozesse und Eigenschaften, die einen Einfluss auf energetische Flüsse und ihre Interaktion mit städtischen Oberflächen haben. Eine thermische Charakteristik einzelner Bezirke über verschiedene Nutzungsklassen bis hin zu einzelnen Materialien wird erstellt. Dabei sind Temperaturdifferenzen von mehreren zehntel Kelvin zwischen den typischen städtischen Oberflächen Dächern und Rasenflächen zu beobachten. Die Resultate zeigen, dass die Verteilung der LST sehr verschieden ist und stark korreliert mit den Landbedeckungen. Es wird dargestellt, welche Stadtstrukturen besonders thermisch belastet sind, welche individuelle thermische Bedeutung einzelne Materialien haben. Besonderes Augenmerk wird auf Möglichkeiten der Beeinflussung durch Abschattung gelegt. Durch Verschattung können Differenzen der Oberflächentemperaturen von mehr als 10 Kelvin erreicht werden. Abschließend werden Modellierungen zur Verifizierung der Kameramessungen sowie zum Aufzeigen des Einflusses minimaler Änderungen in kleinräumigen Klimaten genutzt. / Urban areas differ from surfaces of rural character. They are very modified in their radiation- and energy balance. In this study land-surface temperatures of the city of Berlin are analyzed with the help of satellite pictures of the ASTER- and Landsat-5 and -7 sensors in mesoscale and then extended by extra measurements of an infrared camera in microscale over the course of 17 months. This data combined with GIS based information on different land use and -structures are used for the analysis of spatial and time distribution, as well as for the determination of functional relations between thermal behaviour of surfaces and the related urban structures. The evaluation mainly deals with physical processes and properties that have an influence on energetic flows and their interactions with urban surfaces. A thermal characteristic of individual districts, from different land use classes to specific materials is being created. In this there are differences in temperature of several tenths Kelvin between the typical urban surfaces of roofs and grass areas visible. The results show that the distribution of the LST varies immensely and correlates with the land coverage. It is shown, what urban structures are most thermic burdened, what individual significance specific materials have. Special attention is paid to the different possibilities of the influence through shadow. It is possible to reach a difference of surface temperatures of more than 10 Kelvin by shadow. At the end models with the 3-dimensional ENVImet are used to verify the camera measurements as well as to show the influence of minimal changes in microscale climate.
52

Desenvolvimento de sistemas de geoprocessamento e tecnologia móvel aplicados à agricultura de precisão / Development of geoprocessing systems and mobile technology applied to precision agriculture.

Boemo, Daniel 16 April 2011 (has links)
Being information most important one assets for the development of several areas of knowledge in various sectors of our society and knowing that in recent years with the emergence of new technologies and data sources available for free on the Internet, and also allies this, offering a wide variety of media in a big cloud that today we all know by WEB. Will be shown two solutions that were developed for the CR system Campeiro 7, related to precision farming. One is a module of computer system in which the main function is to extract MDT's from SRTM images of 90m and ASTER images 30 m resolution, and provide data for the structuring of these models, altimetric and slope on files patterns used for GIS mainly linked to agriculture. The purpose of this tool is to facilitate the acquisition of these data and provide simpler methods to accomplish the adjustment of the models and give conditions to perform the comparison of these models with other data types, such as grain production. The other computer system was implemented with mobile technologies for the removal and processing of data related to field activities done on the spot.This system in addition to performing the collection and processing of GPS data in real time, is designed to streamline processes, running on smartphone devices, due to the fact that it possesses features of a laptop. The system was created to shorten the time between the collection, processing and analysis, and also to provide results more quickly, providing alternative methods of information processing using remote resources. It also provides trace real-time ,task done in the field, such as monitoring activities carried by a tractor or a combine using telephone services or Internet. / Sendo a informação um dos bens mais importantes para o desenvolvimento das várias áreas do conhecimento nos mais variados setores de nossa sociedade e sabendo-se que nos últimos anos, com o surgimento de novas tecnologias e fontes de dados disponibilizados gratuitamente na internet, e também aliados a isto, uma oferta dos mais variados meios de comunicação em uma grande nuvem que hoje todos conhecemos por WEB. Serão mostradas duas soluções que foram desenvolvidas para o sistema CR Campeiro 7, ligadas à agricultura de precisão. Uma delas é um módulo de sistema computacional em que a principal funcionalidade é extrair MDT s a partir de imagens SRTM de resolução 90 m e ASTER de resolução 30 m, e prover dados para a estruturação destes modelos, altimétricos e posteriormente de declividade, em padrões de arquivos utilizados em SIG s principalmente ligados a agricultura. A proposta desta ferramenta é agilizar a aquisição destes dados e proporcionar métodos mais simples para realizar a estruturação dos modelos e dar condições de realizar o cruzamento destes modelos com outros tipos de dados, como os de produção de grãos. O outro sistema computacional foi implementado com tecnologias móveis para o levantamento e tratamento de dados ligados as atividades feitas a campo in loco. Este sistema além de realizar a coleta e tratamento de dados GPS em tempo real, foi desenvolvido para agilizar processos, funcionando em dispositivos smartphone, devido ao fato de possuir características de um computador portátil. O sistema foi criado para encurtar o tempo entre a coleta, o processamento e a análise, e também para disponibilizar os resultados de forma mais rápida, proporcionando métodos alternativos de processamento das informações utilizando recursos remotos. Proporciona também o rastreio, em tempo real, de tarefas feitas a campo, como o monitoramento de atividades exercidas por um trator ou por uma colhedora utilizando serviços de telefonia ou de internet.
53

Forest stand delineation through remote sensing and Object-Based Image Analysis

Ortega-García, José Antonio January 2018 (has links)
Forest stand delineation is an essential task of forest management planning which can be time consuming and exposed to subjectivity. The increasing availability of LiDAR data and multispectral imagery offers an opportunity to improve stand delineation by means of remotely-sensed data. Under these premises, ASTER imagery and low-density LiDAR data have been used to automatically delineate forest stands in several forests of Navarra (Spain) through Object-Based Image Analysis (OBIA). Canopy cover, mean height and the canopy model have been extracted from LiDAR data and, along with VNIR ASTER bands, introduced in OBIA for forest segmentation. The outcome of segmentation has been contrasted, on the one hand, assessing segments’ inner heterogeneity. On the other, OBIA’s segments and existing stand delineations have been compared with a new method of geometrical fitting which has been ad hoc designed for this study. Results suggest that low-density LiDAR and multispectral data, along with OBIA, are a powerful tool for stand delineation. Multispectral images have a limited predicting utility for species differentiation and, in practical terms, they help to discriminate between broad-leaved, conifer and mixed stands. The performance of ASTER data, though, could be improved with higher spatial resolution VNIR imagery, specifically sub-metric VNIR orthophotos. LiDAR data, in contrast, offers a great potential for forest structure depiction. This perspective is connected with the increasingly higher resolution datasets which are to be provided by public institutions and the rapid development of drone technology. Complexity of OBIA may limit the use of this technique for small consulting firms but it is an advisable instrument for companies and institutions involved in major forestry projects. / No
54

Utilisation of remote sensing for the study of debris-covered glaciers : development and testing of techniques on Miage Glacier, Italian Alps

Foster, Lesley A. January 2010 (has links)
An increase in the number of debris-covered glaciers and expansion of debris cover across many glaciers has been documented in many of the world’s major glacierised mountain ranges over the last 100 years. Debris cover has a profound impact on glacier mass balance with thick layers insulating the underlying ice and dramatically reducing ablation, while thin or patchy cover accelerates ablation through albedo reduction. Few debris-covered glaciers have been studied in comparison with ‘clean’ glaciers and their response to climatic change is uncertain. Remote sensing, integrated with field data, offers a powerful but as yet unrealised tool for studying and monitoring changes in debris-covered glaciers. Hence, this thesis focuses on two key aims: i) to test the utility of visible/near infrared satellite sensors, such as TERRA ASTER, for studying debris-covered glaciers; ii) to develop techniques to fully exploit the capability of these satellite sensors to extract useful information, and monitor changes over time. Research was focused on four interrelated studies at the Miage Glacier, in the Italian Alps. First, a new method of extracting debris-thickness patterns from ASTER thermal-band imagery was developed, based on a physical energy-balance model for a debris surface. The method was found to be more accurate than previous empirical approaches, when compared with field thickness measurements, and has the potential advantage of transferability to other sites. The high spatial variability of 2 m air temperature, which does not conform to a standard lapse rate, presents a difficulty for this approach and was identified as an important area for future research. Secondly, ASTER and Landsat TM data are used to map debris-cover extent and its change over time using several different methods. A number of problems were encountered in mapping debris extent including cloud cover and snow confusion, spatial resolution, and identifying the boundary between continuous and sporadic debris. Analysis of two images in late summer 1990 and 2004 revealed only a small up glacier increase in debris cover has occurred, confirming other work’s conclusions that the debris cover on Miage Glacier increased to its present extent prior to the 1990s. A third area of research used ASTER DEMs to monitor surface elevation changes of the Miage Glacier over time to update previous studies. Surface velocities on the glacier tongue were also calculated between 2004-2005 using feature-tracking of ASTER orthorectified visible band imagery and ASTER DEMs. However, ASTER DEMs were found to be rather poor for both applications due to large elevation errors in topographically rough parts of the glacier, which prevented a full analysis and comparison of results to previous surface elevation and velocity studies. Finally, the lithological units of the debris cover were mapped, based on the spectral differences of different rock types in the debris layer, providing information both on the location and concentration of different rock types on the surface. Therefore, the identification in the variation in emissivity throughout the glacier surface can be identified, which in turn has an impact upon calculated surface temperatures and ablation respectively. Overall, this research presents a significant contribution to understanding the impact of a debris layer on an alpine glacier, which is an area of key interest and current focus of many present glaciological studies. Since future glacial monitoring will increasingly have to consider supraglacial debris cover as a common occurrence, due to climate warming impacts of glacial retreat and permafrost melting. This contribution is achieved through the successful application of methods which utilise ASTER data to estimate debris thickness and debris extent, and the lithological mapping of debris cover. Therefore, the potential for incorporating these remote sensing techniques for debris-covered glaciers into current global glacier monitoring programs has been highlighted. However the utility of ASTER derived DEMs for surface elevation change analysis and surface velocity estimations in a study site of steep and varied terrain has been identified as questionable, due to issues of ASTER DEM accuracy in these regions.
55

Nytt luftvärnssystem för Sverige : Patriot eller Aster SAMP/T?

Wannehag, Jim January 2017 (has links)
Till följd av Försvarsmaktens tidigare inriktning mot insatsförsvar och den strategiska time-out som präglade början av 2000-talet förfogar luftvärnet idag över luftvärnssystem som är flera decennier gamla. Systemen är inte dimensionerade för att möta dagens högteknologiska motståndare och regeringen har därför beslutat att en ersättare till Robotsystem 97 skall vara på plats senast 2020. Valet står mellan Patriot och Aster SAMP/T, syftet med detta arbete är därför att undersöka och bedöma den militära effektiviteten för respektive luftvärnssystem. Undersökningen baseras på en komparativ analys där luftvärnssystemen jämförs utifrån ett scenario med tillhörande händelseförlopp och kravställningar. Slutligen sammanställs och presenteras resultatet i en multimålmodell för att på ett kvantitativt sätt kunna mäta skillnaderna mellan systemen. Resultatet visar på att Aster SAMP/T har störst potential att vara effektivt i en given kontext men att Patriot också uppfyller de krav som ställs nästintill utan begränsning. Då jämförelsen grundar sig på ett begränsat scenario med specifika förutsättningar är det viktigt att ha i beaktande att resultatet endast har validitet mot det scenario och kravställningar som luftvärnssystemen jämförts utifrån. / As a result of the Swedish Armed Forces previous focus on international operations and strategic timeout in the beginning of the 21st century, the air defense today has surface-to-air missile systems that are several decades old. The systems are not designed to handle today’s high-tech opponent and the government has therefore decided that a replacement for MIM-23 HAWK must be in place by 2020. The choice stands between Patriot and Aster SAMP/T, the purpose of this paper is therefore to investigate and assess the military effectiveness of each surface-to-air missile system. The survey is based on a comparative analysis where the systems are compared to each other in a scenario which includes several events and requirements. Finally, the results are compiled and presented in a multi-goal-model to quantitatively measure the differences between the systems. The result shows that Aster SAMP/T has the greatest potential of being effective in a given context, but that Patriot also meets the requirements almost without any limitations. As the comparison is based on a particularly limited scenario with very specified conditions, it is important to take into account that the result is valid only against the scenario and requirements from which the systems are compared.
56

Characterization of a new endophytic astinproducer, Pelliciarosea asterica, from Aster tataricus

Jahn, Linda 09 December 2015 (has links) (PDF)
Aster tataricus (Asteraceae) is a plant native to Northern Asia and known for its use in the Traditional Chinese and Japanese Medicine. Beside many other secondary metabolites, it contains pentapeptides called astins from which some show an antitumor activity against different human cell lines. Astins are chlorinated, cyclic pentapeptides consisting of proteinogenic and non-proteinogenic amino acids. The astin structure indicates the involvement of non ribosomal peptide synthetases as well as flavin-dependent halogenases. Both enzymes are currently only known from bacteria and fungi. A new endophytic fungus Pelliciarosea asterica was isolated from A. tataricus which produces some of the astins found in the different plant organs. The nearest neighbors of P. asterica are ostropalean fungi from the Stictidaceae lineage (Stictidaceae, Ostropales, Lecanoromycetes, Pezizomycetes, Ascomycota). P. asterica is located in all plant organs of A. tataricus but the highest accumulation of the fungus is found in rhizomes and above-ground organs like leaves or inflorescences. In contrast, the highest astin concentration was found in the roots where nearly no fungus was detectable. P. asterica produces only one of the dichlorinated astins (astin C) in liquid culture, but in A. tataricus all three forms of the dichlorinated astins (A/B and C) were found. This indicates that either the plant is “using” the fungal astin C and metabolize it into one of the other astins or that the fungus, once living inside the plant, is itself producing the other astins. It was also searched for a candidate gene of a halogenase which is essential for the dichlorination of the astins with an antitumor activity. No halogenase could be found by PCR or Southern as well as colony blot, neither in A. tataricus nor in P. asterica. Even the genome sequencing of P. asterica revealed no candidate gene for a halogenase. Endophytes support the plant by suppressing pathogens (antibiosis) or by providing additional nutrients like phosphates or iron to the plant. P. asterica can solubilize different phosphate sources on agar plates. Different fungi are inhibited in growth by P. asterica on agar plates. The endophyte P. asterica from A. tataricus supports its host in different ways and produces secondary metabolites. These secondary metabolites seem to be fungal metabolites either used or degraded by the plant. P. asterica is therefore a good alternative for a possible large-scale production of such antitumor acting astins.
57

Characterization of a new endophytic astinproducer, Pelliciarosea asterica, from Aster tataricus

Jahn, Linda 26 October 2015 (has links)
Aster tataricus (Asteraceae) is a plant native to Northern Asia and known for its use in the Traditional Chinese and Japanese Medicine. Beside many other secondary metabolites, it contains pentapeptides called astins from which some show an antitumor activity against different human cell lines. Astins are chlorinated, cyclic pentapeptides consisting of proteinogenic and non-proteinogenic amino acids. The astin structure indicates the involvement of non ribosomal peptide synthetases as well as flavin-dependent halogenases. Both enzymes are currently only known from bacteria and fungi. A new endophytic fungus Pelliciarosea asterica was isolated from A. tataricus which produces some of the astins found in the different plant organs. The nearest neighbors of P. asterica are ostropalean fungi from the Stictidaceae lineage (Stictidaceae, Ostropales, Lecanoromycetes, Pezizomycetes, Ascomycota). P. asterica is located in all plant organs of A. tataricus but the highest accumulation of the fungus is found in rhizomes and above-ground organs like leaves or inflorescences. In contrast, the highest astin concentration was found in the roots where nearly no fungus was detectable. P. asterica produces only one of the dichlorinated astins (astin C) in liquid culture, but in A. tataricus all three forms of the dichlorinated astins (A/B and C) were found. This indicates that either the plant is “using” the fungal astin C and metabolize it into one of the other astins or that the fungus, once living inside the plant, is itself producing the other astins. It was also searched for a candidate gene of a halogenase which is essential for the dichlorination of the astins with an antitumor activity. No halogenase could be found by PCR or Southern as well as colony blot, neither in A. tataricus nor in P. asterica. Even the genome sequencing of P. asterica revealed no candidate gene for a halogenase. Endophytes support the plant by suppressing pathogens (antibiosis) or by providing additional nutrients like phosphates or iron to the plant. P. asterica can solubilize different phosphate sources on agar plates. Different fungi are inhibited in growth by P. asterica on agar plates. The endophyte P. asterica from A. tataricus supports its host in different ways and produces secondary metabolites. These secondary metabolites seem to be fungal metabolites either used or degraded by the plant. P. asterica is therefore a good alternative for a possible large-scale production of such antitumor acting astins.
58

An ASTER Digital Elevation Model (DEM) for the Darwin-Hatherton Glacial System, Antarctica.

Smith, Nita Jane January 2007 (has links)
The Darwin-Hatherton glacial system is an outlet glacial system in the Transantarctic Mountains, Antarctica, which drains ice from the East Antarctic Ice Sheet into the Ross Ice Shelf. This research provides remotely sensed data that can be used in modeling research for the Darwin-Hatherton glacial system, which in turn can be used in mass balance research for the West Antarctic Ice Sheet. Two improved digital elevation models (DEM) are produced to cover the lower Darwin Glacier and to cover the upper Darwin and Hatherton Glaciers. The new improved DEMs are generated from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite data, with a resolution of 45 m. To produce the two final DEMs, multiple DEMs are firstly adjusted to remove systematic errors and are then stacked and averaged to increase the accuracy and produce the final two DEMs. For the lower Darwin Glacier, 5 DEMs were averaged and in the upper Darwin and Hatherton Glaciers, 6 DEMs were averaged. The accuracy is quantified by a remaining error of + 9 m for the lower Darwin Glacier DEM and + 37 m for the upper Darwin and Hatherton Glaciers DEM. This is a significant improvement from the existing 200 m resolution Radarsat Antarctic mapping project (RAMPv2) DEM which has a remaining error of + 138 m over the lower Darwin Glacier and + 152 m over the upper Darwin and Hatherton Glaciers. The accuracy is assessed by comparing the ASTER and RAMPv2 DEMs to highly accurate ice, cloud and land elevation satellite (ICESat) laser altimetry data. A 15 m resolution, true colour, orthorectified image is provided for the entire Darwin-Hatherton glacial system from ASTER satellite imagery. The DEMs used to orthorectify the ASTER satellite imagery are the two new 45 m resolution ASTER DEMs. Lastly feature tracking was explored as a method for measuring surface ice velocity. This research shows that feature tracking is unsuitable for the Darwin-Hatherton glacial system if using 15 m resolution satellite imagery over a 1 to 4 year time period.
59

Volume Change of the Tasman Glacier Using Remote Sensing

Thomas, Joel Spencer January 2008 (has links)
Mountain glaciers are expected to be the greatest contributor to sea level rise over the next century. Glaciers provide a good indicator of global climate and how to monitor their change is an increasingly important issue for climate science and for sea level rise forecasts. However, there has been little direct measurement of glacier volume change in New Zealand. This study explores the use of remotely sensed data for measuring glacier volume change from 1965 to 2006. Digital photogrammetric methods were used to extract topographic data of the Tasman Glacier from aerial photography and ASTER imagery for the years 1965, 1986, 2002 and 2006. SRTM C band data from 2000 were also analysed. Data were compared to an existing digital elvation model produced from the New Zealand Digital Topographic Database to test for their reliability. Using regression analysis, the data were filtered and points representing rock were used to correct points on the glacier ice for vertical bias. The quality of the data extracted from the aerial photography was good on rock and debris covered ice, but poor on snow. The data extracted from ASTER was much more reliable on snow in the upper glacier than the aerial photography, but was very poor in the lower debris covered region of the glacier. While the quality of the SRTM data is very high, there is a second order distortion present in the data that is evident over elevation differences. However, the overall mean difference of the SRTM rock from TOPODATA is close to zero. An overall trend could be seen in the data between dates. However, the 2006 ASTER data proved unreliable on the debris covered section of the glacier. Total volume change is therefore calculated for the period between 1965 and 2002. The data show a loss of 3:4km³ or 0:092km³ per year, an estimated 6% of the total ice in New Zealand. This is compared to estimates using the annual end of summer snowline survey between 1977 and 2005 of 1:78 km³, or 0:064km³ per year. The spatial resolution of ASTER makes high temporal resolution monitoring of volume change unlikely for the New Zealand glaciers. The infrequency of aerial photography, the high cost and vast time involved in extracting good quality elevation data from aerial photography makes it impractical for monitoring glacier volume change remotely. However, SRTM and other radar sensors may provide a better solution, as the data do not rely heavily on user processing.
60

Quantitative River Profile Analysis to Investigate Exhumation of the Siwalik Foreland Basin, Nepalese Himalaya

Bhattarai, Indu 01 April 2017 (has links)
The Nepalese Himalaya, one of the most active regions within the Himalayan Mountain belt, is characterized by a thick succession of Miocene age Siwalik sedimentary rocks deposited at its foreland basin. To date, much of its tectonic evolution, including exhumation in the Nepalese Siwalik, is poorly understood. This study of a quantitative analysis of the bedrock river parameters should provide crucial information regarding tectonic activities in the area. The study investigated geomorphic parameters of river longitudinal profiles from 54 watersheds within the Siwalik section of the Nepalese Himalaya, for the first time. A total of 140 bedrock rivers from these watersheds were selected using stream power-law function and 30-meter resolution ASTER DEM. The quantitative data from the river longitudinal profiles were integrated with published exhumation ages. Results of this study show, first, a presence of major and minor knickpoints, with a total of 305 knickpoints identified, of which 180 were major knickpoints and the rest were minor knickpoints. Further classifications of knickpoints were based on structures (lineaments extracted from SRTM DEM), lithology, and possible uplift. Second, the Normalized Steepness index (ksn) values exhibited a range from 5.3 to 140.6. Third, the concavity index of streams in the study area ranged from as low as -12.1 to as high as 31.1 and the values were consistently higher upstream of the knickpoints. Finally, integration of the river profile data with the published exhumation ages show that the regions with a high ksn value correspond to the regions with higher incision and, therefore, are likely to have high uplift. The presence of a break in ksn in the eastern section of the study area suggests that the incision is likely accelerated by Main Frontal Thrust (MFT) movements. Erosion of the thrust sheet could have influenced the rapid uplift of the Siwalik due to isostatic processes. Thus, the timing of the source-region exhumation and its rate suggests that MFT-related tectonics, and/or climate processes, likely influenced the landscape evolution of the study area. The results of this study should help in comprehending the neo-tectonic deformation of the Nepalese Himalaya.

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