The event of a default for low-default portfolios, such as sovereign debt or banks, have received much attention as a result of the increasing instabilities in financial markets. The lack of sufficient default information on low-default portfolios complicates the protection of such portfolios. Default protections have typically, in the past, relied on extreme value theory and reporting the value at risk. The focus here, is the application of an engineering concept, accelerated test techniques, to the problem of insufficient data on low-default portfolios. In the application, high-default portfolios serve as stressed cases of low-default portfolios. Since high-default portfolios have more data available, viewing it as a stressed case of a low-default portfolio enables us to extrapolate the data to the low-default portfolio environment, and do estimation such as estimating the default probability for a low-default portfolio. The flexible framework through which the above is achieved, is provided. / Dissertation (MSc)--University of Pretoria, 2016. / Statistics / MSc / Unrestricted

The Gautrain Rapid Rail Link is a state-of-the-art rail route and one of the ten Spatial Development Initiatives planned in Gauteng Province, South Africa. The route comprises two links, namely a link between Tshwane (Pretoria) and Johannesburg and a link between OR Tambo International Airport and Sandton. A total of 10 stations are linked by approximately 80 kilometres of rail along the proposed route. Between Johannesburg and Pretoria in the southern Tshwane region, the rail alignment is underlain by dolomite bedrock for approximately 15km in the vicinity of Centurion between Nelmapius Drive and The Fountains, including nearly 6km elevated on a viaduct. The stability of the rapid rail link constructed over the dolomitic sections was considered a major project risk due to its proneness to sinkholes and subsidences along this route. Construction on heterogeneous soils, pinnacled bedrock and other geohazards posed major challenges to the construction team. To facilitate detailed design and adapt proper foundation options for the viaducts founded over the dolomitic terrain, rigorous and comprehensive ground investigations were conducted by the Bombela Civils Joint Venture (BCJV). This work presents the different ground investigation methods used and how the results have led to the adoption of five suitable foundation solutions namely: large diameter shafts to rock, piles to rock, floating foundations over grouted ground, spread footings on shallow bedrock and concrete U shaped structures. Additional information available on a CD stored at the Merensky Library on 3rd Floor / Dissertation (MSc)--University of Pretoria, 2012. / Geology / unrestricted

In this work we presented an implementation that uses decision trees to learn highly accurate link specifications. We compared our approach with three state-of-the-art classifiers on nine datasets and showed, that our approach gives comparable results in a reasonable amount of time. It was also shown, that we outperform the state-of-the-art on four datasets by up to 30%, but are still behind slightly on average. The effect of user feedback on the active learning variant was inspected pertaining to the number of iterations needed to deliver good results. It was shown that we can get FScores above 0.8 with most datasets after 14 iterations.

Parametrisk design är en process baserad på algoritm där parametrar och regler styr och definierar utformningen av geometriska former. Denna metod att generera och modifiera geometri har länge använts inom arkitekturen på grund av möjligheten att snabbt skapa mycket komplexa och innovativa strukturer. Förutom skapandet av komplicerad geometri erhålls en värdefull vinst i form av tidsbesparing. Det här examensarbetet genomförs tillsammans med WSP Östersund och avser att undersöka möjligheterna med parametrisk design vid projektering av hallbyggnader. Målet är att med hjälp av parametrisk design skapa en modell som gestaltar konstruktionen av en hallbyggnad och vars utformning kan styras med parametrar. Syftet är att automatisera moment i projekteringen som innefattar repetitiva uppgifter och ändringar och på så sätt effektivisera delar ur projekteringsprocessen. Arbetet omfattar dels litteraturstudier som behandlar parametrisk design och projektering av hallbyggnader. I arbetet ingår också framtagning av en parameterstyrd modell med hjälp av programmering i Grasshopper. Resultatet av studien visar att det är fullt möjligt att med hjälp av parametrisk design skapa en modell av en hallbyggnad vars utformning styrs av parametrar. Användningsmöjligheterna för den framtagna modellen bedöms vara störst i projekteringens tidiga skeden. Anledningen till detta är att modellen inte är speciellt detaljerad och att ändringar i parametrarna bara bestämmer hallens utformning i stort. Bestämmelser som dessa fastslås i projekteringens tidiga skeden. Studien genererade ett resultat som med fördel kan verka som underlag för fortsatta arbeten inom parametrisk design. Modellen har utvecklingspotential, både gällande detaljering och användningsområden. Huruvida användandet av modellen kan effektivisera delar ur projekteringens tidiga skeden har i rapporten inte bevisats, utan resonerats fram med hjälp av diskussionsmaterial gällande modellen. Vidare studier inom området behövs för att styrka detta. / Parametric design is a process based on algorithm where parameters and rules manipulate, define and encode the creation of geometry. This way to generate and modify geometry has long been used by architects due to its ability to create complex and innovative structures very quickly. This final project is a collaboration with WSP Ostersund and intends to investigate the capability of parametric design in the process of modeling an industry hall. By using parametric design, the aim is to create a model of an industry hall whose formation can be modified by parameters. The purpose is to make the process of modeling more effective by automate parts of the process that include repetitive and modification work. The project includes reviews of literature within the subject of parametric design and the process of designing industry halls. It also includes the creation of a parametric model through visual programming in Grasshopper. The results of this project proved that parametric design is a solution to manage create a parametric model that present the structure of an industry hall. Because this model exclusively includes the buildings framework and parameters merely adjust the formation in general, the model is most likely useful in the early stages of project planning. The results of this study can advantageously serve as a basis for futured project within the theme parametric design, and the model can furthermore be developed in many ways. This study does not show any evidence that the use of this model can automate and streamline the early stages of the design process, it´s more an assumption established on the result. Further studies are required to prove that the model can lead to an efficiency of the modeling process. / <p>Betyg 210118</p>

Ziel dieser Arbeit ist die Erarbeitung von effizienten (semi-)automatischen Verfahren zur Verknüpfung von Wissensbasen. Eine Vielzahl von Lösungsklassen können zu diesem Zweck eingesetzt werden. In dieser Arbeit werden ausschließlich deklarative Ansätze erörtert. Deklarative Ansätze gehen davon aus, dass das direkte Errechnen von Mappings zwischen Mengen von Ressourcen in vielen Fällen nur schwer möglich ist oder eines nicht vertretbaren Aufwands bedarf. Diese Ansätze zielen daher darauf ab, eine Ähnlichkeitsfunktion sowie einen Schwellwert zu finden, die zur Approximation eines Mappings genutzt werden können. Zwei Herausforderungen gehen mit dieser Modellierung des Problems einher: (a) Effizienz sowie (b) Genauigkeit und Vollständigkeit. Lösungen zu beiden Herausforderungen sowie auf echten Daten basierende Anwendungen dieser Lösungen werden in der Arbeit vorgestellt.

Classification problems with multiple classes and imbalanced sample sizes present a new challenge than the binary classification problems. Methods have been proposed to handle imbalanced learning, however most of them are specifically designed for binary classification problems. Multi-class imbalance imposes additional challenges when applied to time series classification problems, such as weather classification. In this thesis, we introduce, apply and evaluate a new algorithm for handling multi-class imbalanced problems involving time series data. Our proposed algorithm is designed to handle both multi-class imbalance and time series classification problems and is inspired by the Imbalanced Fuzzy-Rough Ordered Weighted Average Nearest Neighbor Classification algorithm. The feasibility of our proposed algorithm is studied through an empirical evaluation performed on a telecom use-case at Ericsson, Sweden where data from commercial microwave links is used for weather classification. Our proposed algorithm is compared to the currently used model at Ericsson which is a one-dimensional convolutional neural network, as well as three other deep learning models. The empirical evaluation indicates that the performance of our proposed algorithm for weather classification is comparable to that of the current solution. Our proposed algorithm and the current solution are the two best performing models of the study.

This thesis analyzes the current transport situation of Arlanda Airport and the two main cities that Arlanda is located between, Stockholm and Uppsala. The purpose of the thesis is to study the efficiency of the different transport alternatives and also to relate it with their current market shares. Besides, in order to do a deeper analysis of Arlanda Airport connectivity some of the busiest airports transport links have been analyzed in terms of availability of different transport alternatives, distance to the city centers and market shares. Because of the high number of cars that currently go to Arlanda, there is a need to reduce the emissions of carbon dioxide. To this end, a prediction of the demand in ten years has been carried out to see what improvements have to be done to make Arlanda a more environmentally friendly airport. The methodology used in order to forecast the demand has been based on a survey conducted at a single point to regular users of the public transportation system. The improvement of the connectivity of Arlanda Airport via public transport alternatives will not only affect the distribution of the current market shares, but also represents a key strategy for pursuing Arlanda’s leadership in achieving environmental goals.

Nomadic computing aims to be a leading short term revolution in the Internet, however to succeed in this the infrastructure, the protocols, the handoff mechanisms have to be designed and implemented to provide mobile computing with both reliability and transparency. A good deal of the work is addressed by mobile IP itself, but addressing wireless diversity is perhaps the most important next step. Many different wireless technologies are available; while one technology might provide wide coverage, another provides higher bandwidth, but can only be deployed locally, even uni-directional ad-hoc links can be used to carry IP traffic. To take full advantage of the potential infrastructure, a mobile device, with multiple network interfaces, should be able to dynamically switch from one link technology to another; hopefully totally transparently to the user. Moreover, having multiple interfaces allows the device to choose, each time a new connection is established, which interface to select to route the datagrams through, based on the type of service desired. In this thesis a possible solution is presented, involving both vertical handoff optimization and policy management. Our testing device is the the SmartBadge v4, provided with a GPRS link and a 802.11b WLAN interface. / Nomadic Computing har för avsikt att revolutionera dagens Internet tillämpningar. För att lyckas måste dock infrastrukturen, IT protokollen och handoff procedurer utformas och implementeras med intentionen att förse mobilt dataöverföring med både driftsäkerhet och autonoma processer. En stor del av de nödvändiga förutsättningarna är tillgängliga tack vare Mobile IP, men mångfalden inom de befintliga Wireless teknologierna utgör fortfarande ett problem. Det stora antalet disponibla Wireless tekniker varierar från teknologierer som förser användaren med en stor täckningsgrad, till sådana som förser användaren med högre bandbredd, begränsad till lokala anv ändningområden. Även Uni-directional ad-hoc links kan läggas i denna lista av mångfald. För att förverkliga fördelarna med den tänkta infrastrukturen fullt ut måste den mobila enheten kunna utföra omkopplingar från den ena wireless teknologin till den andra, med syftet att vara osynlig för användaren. Utöver detta är det meningen att en apparat med många anslutningar ska kunna välja den anslutning som passar bäst, var gång en ny koppling ska göras, beroende på den tjänst som efterfrågas. Det här examensarbetet presenterar en möjlig lösning, som utnyttjar både Vertical Handoff optimering och Policy Management. Prototyp-enheten vi anv änder oss av för att genomföra undersökningen är Smart Badge v4, utrustad med GPRS och 802.11b Wireless LAN anslutningar.

No description available.

Det finns många olika källor där man kan få information om sårbarheter i routrar och switchar. Mängden information gör det dock svårt att på ett enkelt sätt ta reda på vilka tillverkare som drabbas och vilken typ av sårbarheter man hittar i nätverksutrustning. Därmed är det också svårt att veta hur man ska skydda sin utrustning mot attacker. I detta examensarbete analyseras ett antal befintliga sårbarheter i routrar och switchar. Dessa sårbarheter har valts ut genom att i National Vulnerability Database söka på orden ”router” och ”switch”. Målet med analysen är att svara på frågorna vem, vad och varför när det gäller sårbarheter i routrar och switchar. Examensarbetet beskriver vilka tillverkare som drabbas av sårbarheter, vilka typer av sårbarheter som är vanligast i routrar och switchar och varför sårbarheterna har uppstått. Utifrån detta dras slutsatser om vad man som användare ska göra för att undvika attacker mot sin utrustning. I arbetet beskrivs också hur tillverkarna väljer att hantera de sårbarheter som finns i deras produkter. / There are a lot of different sources to information about vulnerabilities in routers and switches. The amount of information means that there is no easy way to find out which vendors are affected by vulnerabilities and what types of vulnerabilities that are found in network equipment. Thereby it is also hard to know how to protect your equipment against attacks. In this thesis a number of already existing vulnerabilities in router and switches are being analyzed. These vulnerabilities have been chosen by searching the National Vulnerability Database using the words “router” and “switch”. The aim of the analysis is to answer the questions who, what and why when it comes to vulnerabilities in routers and switches. The thesis describes which vendors are exposed to vulnerabilities, what types of vulnerabilities that are most common among routers and switches and why these vulnerabilities have came up. Based on this information, conclusions are drawn regarding what the user should do to avoid vulnerabilities in their equipment. The way the companies deal with vulnerabilities in their products is also described.