Positioning in electromagnetic fields

Master's thesis in Computer scienceDrones (or Unmanned Aerial Vehicles) can become an important tool for performing the regular inspection of overhead power lines in difficult terrain. This currently requires a pilot, but if we could detect the position of the power line using magnetic field sensors, we might be able to automatically navigate alongside it. This would also be useful in remotely measuring the amount of current flowing through the conductors. We then focus on the magnetic field around a three-phase single-circuit power line. Using either a mathematical model, or a FFT (Fast-Fourier Transform) of 8 samples of the field, we compute two values per component that are invariant to the unknown current, but depend on the location of the drone. Using CMA-ES (Covariance Matrix Adaptation Evolution Strategy), we estimate the corresponding point given at least two sensors and four invariants per sensor. As suggested by experimental data, we also consider the possibility that each conductor is carrying a different amount of current. Using this approach, we successfully navigate a simulated drone using three magnetic field sensors, where two is the minimum. The estimated position is accurate down to about 1.8mm, needing about 350ms of computational time on a desktop computer. This enables us to position a drone with better accuracy than using a GPS alone. We can also use this method to cancel drift in an INS (Inertial Navigation System)

La prevención de delitos racistas

[ES] Los datos estadísticos sobre el problema del racismo y la xenofobia en España parecen mostrar que la población española es más tolerante con los inmigrantes que los demás países europeos. Sin embargo, el aumento de la inmigración en este país y la experiencia en otros lugares indica que la tolerancia hacia otras etnias se reduce si los recién llegados se acumulan en las grandes ciudades con escasa integración en la sociedad. Para combatir el racismo, y los delitos contra los inmigrantes, se debaten diversas medidas analizando su eficacia.[EU] Arrazakeria eta xenofobiaren arazoaren inguruko datu estatistikoek erakusten dutenez, badirudi Espainiako biztanleak Europako beste herrialde batzuetakoak baino toleranteagoak direla inmigranteen arazoari dagokionez. Hala ere, herrialde honetan inmigrazioak gora egiten duela eta beste herrialde batzuetako esperientziak ikusirik, esan daiteke beste arraza batzuenganako tolerantzia mailak behera egiten duela heldu berriak hiri handietan elkartzen diren eta gizartean parte hartze zuzenik izaten ez duten heinean. Arrazakeriari eta inmigranteen aurkako delituei aurre egiteko hainbat neurri ari dira eztabaidatzen, bakoitzaren eraginkortasuna aztertuz.[FR] Les données sur le problème du racisme et la xénophobie en Espagne semblent montrer que, par rapport aux immigrants, la population espagnole est plus tolérante que les autres pays européennes. Pourtant, l’accroissement de l’immigration dans notre pays et des expériences des autres indiquent que la tolérance vers d’autres ethnies descend lorsque les nouveaux arrivés se concentrent dans les grandes villes et leur intégration sociale et faible. Pour combattre le racisme et les délits contre les immigrants, plusieurs moyens et leur efficacité sont débatus.[EN] Statistics about racism problem and xenophobia in Spain prove that spanish population is more tolerant with regards to immigrant that others european countries. However, the immigration’s increase on our country and others experiences show that the tolerance in respect of others ethnos goes down when the newcomers crow together on big towns and their social integration is weak. Several means and their efficacy to combat racism and crimes against immigrants are discussed

Self-archiving and DSpace@Cambridge

Presentation held at Unilever Centre for Molecular Science Informatics, November 12th 200

Experimental lost circulation and performance simulation studies of 60/40, 70/30, 80/20 and 90/10 OBMs

Master's thesis in Petroleum engineeringLost circulation has been and still is a cost factor for the drilling industry. By using lost circulation material in drilling fluid, it is possible to mitigate unnecessary loss of drilling fluid. This thesis presents characterization, performance simulation and lost circulation performances of four types of oil based mud systems. These are of 60/40, 70/30, 80/20 and 90/10 oil-water ratio. The characterization part deals with rheology measurement and modelling at various temperatures, and is based on direct experimental measurements. The performance simulation study deals with the hole cleaning efficiency of the drilling fluids. The lost circulation part deals with the bridging performance of the drilling fluids at various simulated fracture widths. For the experiment, 13.82 lb/bbl LC-lube (graphite) was used as lost circulation material. The results show that particle size distribution with a D50 at or higher than the fracture width gives a better performance in terms of bridge strength. Similar results have also been documented in previous works. For the studied mud systems, three rheological parameters also show good correlation with the bridge collapse pressure

Innoverer elder bedrifter annerledes enn unge

Tema for denne oppgaven er sammenhengen mellom bedriftsalder og innovasjon. Målet for oppgaven er å studere hva som kjennetegner eldre bedrifters innovasjonsarbeid og hva som skiller disse fra gründerbedrifter. Dette har blitt gjort ved å studere tre casebedrifter og ved å sammenligne funnene med en lignende studie av gründerbedrifter innen samme region og industri. Jeg har funnet at eldre bedrifter i mye større grad kommer med små hyppige forbedringer av sine produkt og at intern FoU er deres største innovasjonskilde. Yngre bedrifter har en mer fleksibel struktur som gjør at de kan tilpasse seg omgivelsene og dette gir økt sannsynlighet for mer radikale innovasjoner. Eldre bedrifter opplever en fare med at de kan utvikle seg i utakt sine omgivelser, en faktor for å opprettholde kontakten med sine omgivelser er å bli sett på som innovativ

Illegal Chinese gold mining in Amansie West, Ghana - an assessement of its impact and implications

Master thesis in development management - University of Agder 2014The thesis’ objective is to assess the impact of Chinese illegal miners in the Amansie West District in Ghana. The illegal mining sector is seen as having several negative effects, environmentally as well as socially and economically. The influx of some 20-50 000 Chinese miners into Ghana is found to increase these impacts. The Chinese illegal miners operate largely on farmland, which is bought from locals for the sum equivalent of approximately 6.5 years of farming income. This leads to a loss of long-term income for the farmer as well as the degradation of large land areas, which in the case of Amansie West is here estimated to cost between GHS 64 and 108 million to restore. Social effects indicated to originate from the Chinese miners are increased prevalence of HIV and malaria as well as symptoms associated with mercury pollution and decline in school attendance. It is thus argued that their presence contributes to a decrease in human capital and farmland, in addition to various positive and negative economic effects including a rise in food prices. Further, the study argues that the government’s limited capacity, and a long-lasting trend of bad implementation of the country’s small-scale mining policies, is a contributor to the situation’s magnitude. In relation to this it is also found that Ghana’s policy framework for the small-scale mining sector can be described as insufficient in both mitigating the impacts and solving the situation. This entails a low level of participation between the government and the grass-root, as well as the former’s lack of provision of community needs like infrastructure and fertilizers. The latter is argued to increase local’s susceptibility to welcome the Chinese miners as they contribute to increased income for local miners and as well as the provision of infrastructure and public needs through something reminiscent of CSR initiatives

Evaluation of the Spherical Flange Concept for a Rocket Engine

Due to the inherent tolerance variability of hardware, flange misalignments occur during installation of mating components for a liquid propellant rocket engine. Flange misalignments include axial, lateral, and angular offsets. If these misalignments are high, they can impart significant loads into the two mating components. These significant loads can then be a driver in the design of the propellant ducts. Such was the case for the Rocketdyne RS-83 engine design for the Space Launch Initiative Program. To address this flange misalignment issue, Marshall Space Flight Center joined with Rocketdyne to develop and test a spherical flange system that allows for misalignment, yet reduces loads imparted, and at the same time provides sufficient sealing against leakage. The flange design was tested to evaluate and compare performance parameters such as misalignment and leakage. The environmental conditions ranged from -100 to 400 degrees Fahrenheit (F) with 1000 to 4000 pounds per square inch gage (psig) pressure. The desirable design features will be extracted and synthesized into a new flange design concept. This paper will address the spherical flange design and the test results

Shear flexibility for structures

This device comprises a flexible sheet member having cross convolutions oriented 45.degree. to the shear vector with spherical reliefs at the convolution junctions. The spherical reliefs are essential to the shear flexibility by interrupting the principal stress lines that act along the ridges of the convolutions. The spherical reliefs provide convolutions in both directions in the plane of the cross-convolution ridges

Seismic Event Classification using Machine Learning

The manual detection of seismic events is a labor intensive task, requiring highly skilled workers continuously analyzing recorded waveforms. Previous work has shown the potential of machine learning methods for aiding in this task, and that deep neural networks are able to learn important patterns in seismic recordings. This study aims to develop a deep neural network to classify earthquake-, explosion and noise events using long beamformed waveform snippets from NORSAR's ARCES array. The final model was evaluated using an unseen test set and on recordings of the North Korean nuclear weapons tests. I developed custom augmentation methods in order to combat the uneven class distribution, and several preprocessing techniques were deployed in pursuit of performance. Models developed for similar data, state-of-the-art multivariate time series models, as well as self-developed models were experimented with and evaluated. Analysis of the results demonstrated that the final model can classify noise and explosion events with a high degree of accuracy, while earthquake classifications were less reliable. I conclude that deep neural networks can learn distinguishing features and detect events of interest on long beamformed three-component waveforms.Masteroppgave i informatikkINF399MAMN-INFMAMN-PRO