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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.
161

Automated Extraction and Retrieval of Metadata by Data Mining : a Case Study of Mining Engine for National Land Survey Sweden

Dong, Zheng January 2010 (has links)
Metadata is the important information describing geographical data resources and their key elements. It is used to guarantee the availability and accessibility of the data. ISO 19115 is a metadata standard for geographical information, making the geographical metadata shareable, retrievable, and understandable at the global level. In order to cope with the massive, high-dimensional and high-diversity nature of geographical data, data mining is an applicable method to discover the metadata. This thesis develops and evaluates an automated mining method for extracting metadata from the data environment on the Local Area Network at the National Land Survey of Sweden (NLS). These metadata are prepared and provided across Europe according to the metadata implementing rules for the Infrastructure for Spatial Information in Europe (INSPIRE). The metadata elements are defined according to the numerical formats of four different data entities: document data, time-series data, webpage data, and spatial data. For evaluating the method for further improvement, a few attributes and corresponding metadata of geographical data files are extracted automatically as metadata record in testing, and arranged in database. Based on the extracted metadata schema, a retrieving functionality is used to find the file containing the keyword of metadata user input. In general, the average success rate of metadata extraction and retrieval is 90.0%. The mining engine is developed in C# programming language on top of the database using SQL Server 2005. Lucene.net is also integrated with Visual Studio 2005 to build an indexing framework for extracting and accessing metadata in database.
162

Road Traffic Noise - A study of region Skåne, Sweden

Farcas, Florentina January 2008 (has links)
Since the first car appeared, the pollution on the roads became an issue, which is still mainly unsolved. Too many people complain about traffic noise. Various methods have been developed that aimed at minimizing the noise pollution and improving the environment. This thesis presents the problems posed by noise pollution, covers the background of noise pollution and its effects on human health. Another important part of the thesis covers the method of noise calculation which applies in specific Nordic countries. The main goal of the thesis is to present maps of noise levels on roads for region Skåne in Sweden. Because the regulation and the limits for noise levels are different for different countries, I could find various calculators for traffic noise. Australia, England, USA have the noise level calculators open for public. Another professional calculator, SoundPlan, is a program that can perform a very accurate calculation for traffic noise but only for small areas. Because of this disadvantage, the request for my thesis was to provide a program which can calculate traffic noise level for wide areas. As a master student specialist in GIS (Geographic Information System) it was natural to develop the traffic noise calculator with available GIS tools. The software system to calculate the traffic noise maps was implemented in ArcMap 9.1, a GIS program which allows creation of tools, according to a mathematical description of noise calculator. The mathematical description is based on the Nordic Prediction method, a document which set up requirements for prediction of road traffic noise. ArcMap 9.1 allows the development of extensions in different programming languages. The tools implemented in this thesis are written in Visual Basic. The thesis work implements several tools for calculating noise levels, starting from the basic traffic noise level and introducing additional noise corrections to perform more accurate noise calculation. The additional corrections could be added because I had access to additional data regarding buildings and population location. The available population data from Lund gave me the opportunity to create a tool which performs population exposure to noise in this region.
163

Undifferenced GPS for Deformation Monitoring

Andersson, Johan Vium January 2006 (has links)
<p>This thesis contains the development of a deformation monitoring software based on undifferenced GPS observations. Software like this can be used in alarm systems placed in areas where the earth is unstable. Systems like this can be used in areas where people are in risk of getting hurt, like in earthquake zones or in land slide areas, but they can also be useful when monitoring the movements in buildings, bridges and other artefacts.</p><p>The main hypotheses that are tested are whether it is possible to detect deformations with undifferenced observations and if it is possible to reach the same accuracy in this mode as when working in a traditional mode where the observations are differenced.</p><p>The development of a deformation monitoring software based on undifferenced GPS observations is presented. A complete mathematical model is given as well as implementation details. The software is developed in Matlab together with a GPS observation simulator. The simulator is mainly used for debugging purposes.</p><p>The developed software is tested with both simulated and real observations. Results from tests with simulated observations show that it is possible to detect deformations in the order of a few millimetres with the software. Calculations with real observations give the same results. Further, the result from calculations in static mode indicates that the commercial software and the undifferenced software diverge a few millimetres, which probably depends on different implementations of the tropospheric corrections. In kinematic mode the standard deviation is about 1 millimetre larger in the undifferenced mode than in the double differenced mode. An initial test with different observation weighting procedures indicates that there is a lot of potential to improve the result by applying correct weights to the observations. This is one of the aims in the future work within this project.</p><p>This thesis are sponsored by the Swedish Research Council for Enviroment, Agricultural Sciences and Spatial Planning, FORMAS within the framework “Monitoring of construction and detection of movements by GPS ref no. 2002-1257"</p>
164

Numerical modelling of fluid flow and particle transport in rough rock fracture during shear

Koyama, Tomofumi January 2005 (has links)
<p>The effects of different shearing processes and sample sizes on the fluid flow anisotropy and its impact on particle transport process in rough rock fractures are significant factors that need to be considered in the performance and safety assessments of underground nuclear waste repositories. The subjects, however, have not been adequately investigated previously in either laboratory experiments or numerical modeling. This thesis addresses these problems using numerical modeling approaches.</p><p>The modeling consists of two parts: 1) fluid flow simulations considering more complex but realistic flow boundary conditions during shear processes that cannot be realized readily in laboratory experiments, using digitalized fracture surfaces scanned in the laboratory, so that anisotropic fluid flow induced by shearing with channeling phenomenon can be directly simulated and quantified; 2) particle tracking simulations to demonstrate the impacts of such channeling effects on characteristic properties of particle transport. The numerical method chosen for the simulations is the Finite Element Method (FEM). Scale effects were considered in the simulations by using fracture surface samples of different sizes.</p><p>The distributions of fracture aperture during shear were obtained by numerically generating relative translational and rotary movements between two digitalized surfaces of a rock fracture replica without considering normal loading. From the evolutions of the aperture distributions during the shearing processes, the evolutions of the transmissivity fields were determined by assuming the validity of the cubic law locally. A geostatistical approach was used to quantify the scale effects of the aperture and transmissivity fields. The fluid flow was simulated using different flow boundary conditions, corresponding to translational and rotary shear processes. Corresponding to translational shear (with a 1 mm shear displacement interval up to a maximum shear displacement of 20 mm), three different flow patterns, i.e., unidirectional (flow parallel with and perpendicular to the shear direction), bi-directional and radial, were taken into account. Corresponding to rotary shear (with a 0.5o shear angle interval up to 90o), only the radial flow pattern was considered. The particle transport was simulated using the Particle Tracking Method, with the particles motion following the fluid velocity fields during shear, as calculated by FEM. For the unidirectional particle transport, the breakthrough curves were analyzed by fitting to an analytical solution of 1-D advection-dispersion equation. The dispersivity, Péclet number and tracer velocity, as well as their evolutions during shear, were determined numerically.</p><p>The results show that the fracture aperture increases anisotropically during translational shear, with a more pronounced increase in the direction perpendicular to the shear displacement, causing significant fluid flow channelling. A more significant increase of flow rate and decrease in travel time of the particles in the direction perpendicular to the shear direction is predicted. The particle travel time and characteristics are, correspondingly, much different when such effects caused by shear are included. This finding may have an important impact on the interpretation of the results of coupled hydro-mechanical and tracer experiments for measurements of hydraulic properties of rock fractures, because hydraulic properties are usually calculated from flow test results along the shear directions, with the effects of the significant anisotropic flow perpendicular to the shear direction ignored. The results also show that safety assessment of a nuclear repository, without considering the effects of stress/deformation of rocks on fluid flow and transport processes, may have significant risk potential. The results obtained from numerical simulations show that fluid flow through a single rough fracture changes with increasing sample size, indicating that representativehydro-mechanical properties of the fractures in the field can only be accurately determined using samples of representative sizes beyond their stationarity thresholds.</p>
165

Kemisk stabilisering av gruvavfall från Ljusnarsbergsfältet med mesakalk och avloppsslam : Chemical stabilization of mine waste with sewage sludge and calcium carbonate residues

Höckert, Linda January 2007 (has links)
Chemical stabilization of mine waste from Ljusnarsbergsfältet with sewage sludge and calcium carbonate residues Mine waste from Ljusnarsbergsfältet in Kopparberg, Sweden, is considered to constitute a great risk for human health and the surrounding environment. Some of the waste rock consists of sulphide minerals. When sulphide minerals come into contact with dissolved oxygen and precipitation, oxidation may occur resulting in acid mine drainage (AMD) and the release of heavy metals. The purpose of this study has been to characterise the waste material and try to chemically stabilize the waste rock with a mixture of sewage sludge and calcium carbonate. The drawback of using organic matter is the risk that dissolved organic matter can act as complexing agents for heavy metals and in this way increase their mobility. An additional study to examine this risk has therefore also been performed. The project started with a pilot study in order to identify the material fraction that was suitable for the experiment. When suitable material had been chosen, a column test was carried out for the purpose of studying the slurry’s influence on the mobility of metals along with the production of acidity. To clarify the organic material’s potential for complexation a pH-stat batch test was used. Drainage water samples, from the columns, were regularly taken during the experiment. These samples were analyzed for pH, electrical conductivity, alkalinity, redox potential, dissolved organic carbon (DOC), sulphate and leaching metals. The effluent from the pH-stat-test was only analyzed on a few occasions and only for metal content and change in DOC concentration. The results from the laboratory experiments showed that the waste rock from Ljusnarsberg easily leached large amounts of metals. The stabilization of the waste rock succeeded in maintaining a near neutral pH in the rock waste leachate, compared to a pH 3 leachate from untreated rock waste The average concentration of copper and zinc in the leachate from untreated waste rock exceeded 100 and 1000 mg/l respectively, while these metals were detected at concentrations around 0.1 and 1 mg/l, respectively, in the leachate from the treated wastes. Examined metals had concentrations between 40 to 4000 times lower in the leachate from treated waste rock, which implies that the stabilization with reactive amendments succeeded. The long term effects are, however, not determined. The added sludge contributed to immobilize metals at neutral pH despite a small increase in DOC concentration. The problem with adding sludge is that if pH decreases with time there is a risk of increased metal leaching.
166

WIND TURBINE FOUNDATIONS IN CLAY : Technical and economic considerations for proposals for wind turbine foundations

Papagiannis, Michail January 2018 (has links)
This thesis approaches the problem of the cost-efficient wind turbine foundation on an onshore site of clayey soil characteristics. The given soil stratigraphy includes a layer of clay and two sands of different density. The characteristics of the soil and the water level that were used as input come from a site in Peloponissos, Greece. The applied wind, static and seismic loads on this study were resolved with the German DIN standards, and other related research and European standards. The safety factors were adjusted for wind turbines. For the pile solution, after the bearing and overturning adequacy against the horizontal and vertical loads was proven with the calculation of the DIN equations, then the model was inserted in the Pfahl program using DIN 4017 equations to calculate settlements. Firstly, a shallow foundation of various dimensions in the clay layer over the water level with all the necessary checks was considered. Afterward, a deep foundation solution of a single bored pile, with reinforcement steel casing, of various diameters was investigated. The different foundation solutions were assessed and compared on a technical and economic basis. As a conclusion, the 0.70 meter diameter single pile was chosen as the best solution because it needs only a few days for construction, and it is the most cost-efficient. The chosen circular footing was of a diameter of 10 meters and 1.5 meter raft thickness, but proved unfeasible because of high excavations costs. The checks on the DIN standards and Eurocode that set the boundaries for the design in the two cases were recognised and possible future work goals were discussed.
167

Friktion mellan mobil vattenbarriär och mark / Friction between mobile water barriers and ground

Sollander, Joel, Svensson, Marcus January 2018 (has links)
Översvämningar är en naturkatastrof som uppkommer vid stor variation i vattentillförsel, exempelvis vid regn eller snösmältning. Detta är ett problem som man länge har bekämpat genom att bygga upp barriärer för att hålla vattnet borta. Tidigare har barriärerna vanligen byggts av sandsäckar, men under de senaste decennierna har många alternativ utvecklats för att göra uppbyggandet enklare och effektivare. Geodesign Barriers AB är ett företag som utvecklat mobila vattenbarriärer med syftet att vara snabba och enkla att montera samt platseffektiv när den inte används. Barriären är utvecklad för att kunna klara stora vattentryck, men vissa markförhållanden ställer högre krav på konstruktionen. Därför har man utvecklat två komplement som ökar barriärens kapacitet. Det ena är förankringsstag som förankras i marken och det andra är en skopa som monteras på barriärens undersida. Syftet har varit att med hjälp av tester i fält, ta reda på när respektive komplement bör användas på den undersökta modellen EUR125.
168

Study of a new method to measure the stresses in rock by image technology : Use of sawn slots and DIgital Image Correlation

Emanuelsson, Patrik January 2018 (has links)
In rock constructions and mining it is important to know the current stress situation in the rock due to safety and construction reasons. Two of the widely used stress measurement methods are overcoring and hydraulic fracturing. Both methods are expensive, need new boreholes, and are complex and time consuming. The methods are also limited by the number of successfully achieved measurements series. An alternative method is therefore investigated by locally relieving stresses around the borehole wall using sawn slots. To determine the stresses in the rock, strain measurements will be done using optics and image processing of images taken before and after cutting of the slots. The images will be processed by a technique called Digital Image Correlation (DIC), a method where the pixels are fitted between the images by the greyscale. The thesis is roughly divided into three parts. The first part explains the basics of rock stresses and current stress measurement methods. The second part is a literature study of the theory behind optics and DIC. There is also a study about if it is possible to use optics from a smartphone and how it differs from a reference commonly used camera in DIC application. Last part consists of numerical calculations in 2D to investigate if there is a possibility to relieve the stress around the borehole walls by cutting slots. With the optics from a smartphone the borehole wall can be in focus on just a few millimeters distance. DIC is a well-developed method which has a good precision when being conducted right and with a good image quality. The combination of using a smartphone and DIC is, however, not fully investigated yet. Only one comparable study was found. It used a Sony tablet and measured the deformations instead of strains. However, that study showed that the measurement error was around 1% compared to the reference camera. When translating deformations into strains, it is most likely that the error will increase, because the error will also be affected from the difference in deformation before and after cutting the slots. The numerical part showed that it’s possible to relieve the stress at parts of the borehole walls for the investigated conditions. To fully relieve the stresses around the borehole wall, it is necessary to have two slots with a short c-c distance and relatively deep slots. In this case a c-c distance of 15 mm and slot depth of at least 25 mm are recommended. / Vid projekt inom berganläggningar och gruvor är det viktigt att känna till de rådande spänningar i berget i ett säkerhets- och konstruktionsperspektiv. I Sverige används framförallt två undersökningsmetoder - överborrning eller hydraulisk spräckning. Två metoder som dock är dyra och relativt få mätserier kan genomföras. En alternativ metod har därför undersökts där borrhålsväggen lokalt avlastas genom sågade slitsar. Töjningsmätning sker genom att fotografera borrhålsväggen innan och efter sågning av slitsarna. Därefter sker bildbehandling via Digital Image Correlation (DIC). En metod som jämför en pixels placerings förändring genom att matcha pixeln via gråskalan. Examensarbetet kan man säga är grovt indelat i tre delar. Den första delen innefattar teorin som handlar om bergspänningar samt nuvarande mätmetoder för att mäta bergsspänningar. Andra delen är en litteraturstudie som behandlar den bakomliggande teorin för optik och bildbehandling med DIC samt en kort undersökning om det är möjligt att använda den optiska tekniken som finns i en smartphone. Sista delen utgörs av numeriska modelleringar i 2D för att verifiera om det går att fullständigt avlasta ett borrhål genom sågade slitsar. Med optik som finns i en smartphone kan bergväggen vara i fokus på bara ett par millimeters avstånd. DIC i sig är en teknik som är så pass utvecklad att precisionen i mätningarna är väldigt god. Förutsatt att bildbehandling görs korrekt och bildkvalitén är god. Kombinationen med optik liknande den från smartphone och bildbehandling med DIC är dock inte fullständigt undersökt. Enbart en jämförbar studie har hittats där deformationsmätningar har gjort med hjälp av en Surfplatta från Sony. Denna undersökning visade att mätfelet mot en referenskamera är cirka 1%. Dock förstärks mätfelet vid töjningsmätningar. Förstärkningen beror dock även av deformationsskillnaden mellan innan och efter avlastning. Den numeriska delen har visat att det går att lokalt avlasta bergväggen fullständigt för det undersökta spänningsförhållandet. Dock krävs det att två slitsar sitter på ett litet c-c avstånd samt är relativt djupa. Två undersökta slitsuppsättningar har visat på fullständigt avlastning, samt ytterligare ett fall som skulle kunna vara användbart.
169

Stabilization of Soft Soil with Lime and PetritT-An Experimental Study

Söderlund, Olov January 2018 (has links)
No description available.
170

Soil profile analysis by vibration theory and the natural frequency : Applied on a case project

Björklind, Malin January 2018 (has links)
To explore soil conditions at sites of infrastructure projects a number of geotechnical soundings are performed at appropriate intervals. Results are, in the nature of their set up, limited to the specific points at which the sounding is performed. To safely assume the area between bore holes a new method is applied and tried at the case railroad project Stenkumla – Dunsjö. By applying vibration theory in conjunction with the studied soils’ geodynamic properties the natural frequency for the soil can be calculated. The properties of the natural frequency also makes it possible to detect in vibration measurements. The method studied in this master thesis is that of utilizing the natural frequency of the soil to try and establish a soil profile from vibration measurements.  An important step in the method is to transform the vibration with the Fast Fourier Transform algorithm. This allows the comparison and analysis of natural frequencies. The measurements were performed by using and attaching an accelerometer to a train.  Results are partly transformed measurement data in frequency graphs and partly natural frequency calculations according to the site investigations. These are compared in the analysis section to try to confirm the methods’ reliability and to see if the method can be used to refine geotechnical investigations.  The reliability of the method is tested by watching for the expected frequencies from the calculations in the measurement data.  The method show more consistency closer to the ground surface rather at greater depths. It is also more reliable for stark contrast layers, i.e. if the soil layers have much of the same properties then it is difficult to spot the differing natural frequencies, as they are too similar.  In trying to establish the soil profile between bore holes the method is inconclusive, partly due to the fact that the investigated area consists of relatively alike soil layers that make the result graphs difficult to get information from. However, the suggested soil profiles from the analysis of this part of the master thesis bear resemblances to bore holes close by, so the method can be usable in some regard. Quality of measurement results would probably be better by running the train faster than was done in this master thesis. The quality of the analysis would also benefit from performing specific soundings to establish the soils’ geodynamic properties rather than using recommended empirical formulas as were used here.  The primary possible application for this method is to use it as a prioritizing tool at an early stage in infrastructure projects. Running the vibration measurement and getting a preliminary picture of the soil conditions could act as a way of steering investigations resources to where greater shifts in the data occur. / I det förberedande skedet inför infrastrukturprojekt genomförs geotekniska undersökningar för att kartlägga jordförhållanden. Detta genomförs bland annat med ett antal olika borrhålsmetoder. Genom sin utförandeform levererar dessa resultat som, strikt uttryckt, är knutna till de specifika punkter där de utförs. I detta examensarbete provas en ny metod där jordprofilen mellan- och vid punkten för borrhål ska kartläggas. Metoden provas ut på järnvägsprojektet Stenkumla – Dunsjö.  Vibrationsteori och geodynamiska egenskaper hos jorden utnyttjas för att fastställa olika jordlagers egenfrekvens. Egenfrekvensens definition gör det möjligt att detektera denna i vibrationsmätningar. Metoden som provas i examensarbetet är att genom vibrationsmätningar fastställa jordprofilen baserat på jordlagrens egenfrekvens.  Ett viktigt steg i metodens process är att transformera resultatet från vibrationsmätningen med Fast Fourier Transformation, en algoritm för databehandling. Genom att applicera Fast Fourier Transformation kan en jämförelse mellan egenfrekvenser från olika källmaterial göras.  De primära vibrationsmätningarna genomfördes genom att fästa en accelerometer på ett tåg. Resultat består i transformerade grafer från vibrationsmätningar samt egenfrekvensberäkningar baserade på de geotekniska undersökningarna vid projekt Stenkumla – Dunsjö. På detta följer en jämförande analys där metodens tillförlitlighet och applicerbarhet runt geotekniska undersökningar diskuteras.  Tillförlitligheten testas genom att identifiera beräknade förväntade värden på egenfrekvensen i mätdatat från tåget. Metoden visar högre tillförlitlighet närmare markytan än djupare ner i jordprofilen. Metodens precision är mer utvecklad för jordprofiler där jordlagren är differentierade från varandra i dess egenskaper. Detta uppstår som en följd av att mer lika drag hos jordlagren får liknande egenfrekvens, vilket gör dem svårare att identifiera och särskilja i frekvensspektrat.  Metoden visade sig vara ofullständig i att fastställa en jordprofil mellan geotekniska borrprover. En anledning till detta är att det område som användes för vibrationsmätningar består av en jordprofil utan allt för varierande egenskaper, vilket gör att en tillräckligt tillförlitlig analys är omöjlig med den mängd data som fanns att tillgå. Den jordprofil som itererades fram i analysavsnittet har dock liknande uppbyggnad som de jordprofiler som fastställts av geotekniker i den geotekniska undersökningsrapporten, vilket ändå tyder på viss användningspotential. Kvalitén på vibrationsmätningen skulle förbättras av att öka farten, och så vibrationen, på tåget som mätaren var fäst på. En annan förbättringsmöjlighet är att få tillgång till uppmätta geodynamiska egenskaper hos jorden istället för de empiriska formler som användes i detta arbete.  Det primära användningsområdet för metoden är att använda den som ett prioriteringsverktyg i ett tidigt skede vid infrastrukturprojekt. Genom att genomföra en vibrationsmätning kan en preliminär bild av jordförhållandena erhållas. Detta kan sedan användas som ett sätt att styra geotekniska undersökningsresurser mer effektivt mot områden där stora avvikelser i vibrationsdatat identifierats.

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