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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.
1

Penningtvätt : Identifiering och analys av tillämpade metoder för att mäta penningtvätt / Money laundering : Identification and analysis of the methods applied to measure money laundering

Rönliden, Johan, Andersson, Adam January 2014 (has links)
Penningtvätt är ett ämne som under de senaste åren fått mycket uppmärksamhet. Nya lagar och regleringar med målsättningen att förebygga och bekämpa penningtvätt har införts. För att uppskatta problemets storlek har ett flertal estimat beräknats med hjälp av olika metoder. I denna uppsats har vi valt att fokusera på de metoder som används för att beräkna estimat, då det finns tecken som tyder på att estimaten som beräknas sällan utsätts för kritik.Syftet med uppsatsen har varit att undersöka och jämföra tre av de idag vanligaste metoderna för att beräkna penningtvättens storlek. De vanligaste modellerna är Walkermodellen, Zdanowicz metoder för handelsbaserad penningtvätt och en två-sektor modell vilka har utgjort fokus i denna studie. Studien är av kvalitativ karaktär med en induktiv ansats där empirin består av de utvalda metoderna.Att göra en exakt mätning av storleken på penningtvätten är naturligtvis inte möjligt, utan det handlar istället om att göra en så bra uppskattning som möjligt. Resultatet av vår undersökning visar att de tre metoderna skiljer sig helt från varandra. Vilken metod som är lämpligast beror på sammanhanget, vilket är viktigt att ha i åtanke när någon tar del av de estimat som beräknats. Zdanowicz metod mäter exempelvis inte total penningtvätt för ett land, men är samtidigt den som bäst mäter kapitalförflyttning vid handel mellan länder. Av de tre metoder vi tagit upp i vår undersökning är Walkermodellen den som lämpar sig bäst för att beräkna penningtvätten globalt, men den har en svaghet i att den till stor del förlitar sig på experters kunskaper och erfarenheter. Två-sektor modellen har sin utgångspunkt i mikroekonomisk teori och får anses ha en högre reliabilitet än Walkermodellen, men går dock inte att tillämpa globalt på samma sätt som Walkermodellen. Två-sektormodellen mäter heller inte hur mycket pengar som tvättas mellan länder så som de andra två metoderna gör. / Program: Civilekonomprogrammet
2

FATIGUE CHARACTERIZATION OF RISERS AND PIPELINES UNDER REALISTIC VARIABLE AMPLITUDE LOADING AND THE INFLUENCE OF COMPRESSIVE STRESS CYCLES

Iranpour, Mohammad 11 January 2013 (has links)
One of the most prominent factors affecting the performance and longevity of risers is vortex induced vibration (VIV), which can cause severe fatigue damage, especially in risers used in deep waters. The available approaches for analyzing VIV induced fatigue in risers mainly focus on the VIV aspect of the problem; indeed less attention has been paid on the effect of VIV on a riser’s fatigue life and in prediction of fatigue life using various models. This dissertation first demonstrates how one can characterize fatigue of pipes and risers using an equivalent plate specimen as opposed to using a pipe specimen, thereby simplifying the task, yet obtaining good accuracy. Actual variable amplitude loadings (VAL) are used to study the fatigue crack growth in risers’ material with a focus on the various influencing parameters. Extensive experimental investigations are performed, followed by analytical and computational nonlinear finite element analyses. It is shown that the higher harmonics do cause significant fatigue damage, thus their influence should not be ignored. The influence of load interaction effects is also investigated, focusing on the fatigue crack growth retardation effects due to tension overloads, as well as the acceleration effects due to compression underloads. The crack closure concept is then used to explore into both the fatigue retardation and acceleration effects within a VAL scenario. An effective method for calculation of the stress intensity factor is proposed, which considers only the tensile portion of the stress range, while proposing another effective approach for accounting for the influence of compressive stress cycles. Moreover, a two-parameter approach is used in this dissertation, relating the fatigue crack growth rate (FCGR) to the crack tip opening displacement (CTOD). It is shown that the CTOD provides adequate information for calculating the FCGR under VAL, and it can be effectively used to account for the influence of the compressive stress cycles. The experimental investigation also considers the retardation effect resulting from the applied peak tensile overload cycles (TOLC) and the influence of various so-called “clipping” levels, demonstrating the significant influence of the TOLC on crack growth retardation in VAL.
3

Modelagem e medi??es de ondas de r?dio para predi??o de perda de propaga??o em ambientes urbanos

Martins, Ronaldo de Andrade 12 June 2006 (has links)
Made available in DSpace on 2014-12-17T14:55:23Z (GMT). No. of bitstreams: 1 RonaldoAM.pdf: 2082162 bytes, checksum: 2dd11d30b856b23cf429317a1e68bfbe (MD5) Previous issue date: 2006-06-12 / In this dissertation new models of propagation path loss predictions are proposed by from techniques of optimization recent and measures of power levels for the urban and suburban areas of Natal, city of Brazilian northeast. These new proposed models are: (i) a statistical model that was implemented based in the addition of second-order statistics for the power and the altimetry of the relief in model of linear losses; (ii) a artificial neural networks model used the training of the algorithm backpropagation, in order to get the equation of propagation losses; (iii) a model based on the technique of the random walker, that considers the random of the absorption and the chaos of the environment and than its unknown parameters for the equation of propagation losses are determined through of a neural network. The digitalization of the relief for the urban and suburban areas of Natal were carried through of the development of specific computational programs and had been used available maps in the Statistics and Geography Brazilian Institute. The validations of the proposed propagation models had been carried through comparisons with measures and propagation classic models, and numerical good agreements were observed. These new considered models could be applied to any urban and suburban scenes with characteristic similar architectural to the city of Natal / Nesta tese novos modelos de predi??o de perda de percurso de propaga??o s?o propostos a partir de t?cnicas de otimiza??es recentes e de medi??es de n?veis de pot?ncias obtidas para as ?reas urbana e suburbana de Natal, cidade do Nordeste Brasileiro. Estes novos modelos s?o: (i) um modelo estat?stico que foi implementado baseado na adi??o de estat?sticas de 2a. ordem para a pot?ncia e a altimetria do relevo ao modelo de perdas lineares; (ii) um modelo com redes neurais artificiais que usou o treinamento do algoritmo backpropagation, a fim de obter a equa??o de perdas de propaga??o; (iii) um modelo baseado na t?cnica dos trajetos aleat?rios, que considera a aleatoriedade da absor??o e do caos do meio ambiente e que seus par?metros desconhecidos para a equa??o de perdas de propaga??o s?o determinados atrav?s de uma rede neural. A digitaliza??o do relevo das ?reas urbanas e suburbanas de Natal foi realizada atrav?s do desenvolvimento de programas computacionais espec?ficos e foram usados os mapas existentes no Instituto Brasileiro de Geografia e Estat?stica. As valida??es dos modelos propostos de predi??o de perda de propaga??o foram realizadas atrav?s de compara??es com medidas e modelos cl?ssicos de propaga??o, obtendo-se boas concord?ncias num?ricas. Estes novos modelos poder?o ser aplicados a qualquer cen?rio urbano e suburbano com caracter?sticas arquitet?nicas semelhantes ? cidade de Natal

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