In this thesis, the Train Power System Simulator (TPSS) has been compared and verified with the commercial simulator TracFeed® Simulation (TracFeed). The basis for the comparison was a given part of the Swedish railway system, with steel transportation trains. Primarily, emphasis was placed on running time and energy consumption in simulation results. Two transformer systems were analyzed, booster and auto transformers. The high voltage transmission line, parallel to the railroad track, was disconnected in some simulations.

In this thesis some different modulation schemes for xDSL-techniques are compared. The investigated techniques are ADSL, G.lite, ADSL2, HDSL, SHDSL and VDSL. The modulation methods used are DMT, CAP and different versions of PAM. Several broadband techniques also use Trellis Coded Modulation (TCM) to increase the coding gain of the transmission. For each one of the different modulation methods the signal-to-noise ratio is calculated for generating a bit error rate probability of 10-7.

The goal of this Master thesis has on the one hand been to create a simulation environment for robots, where not only the simulations in this work can be performed, but also similar robot simulations, and on the other hand to study regulators that can increase the possibilities of rejecting disturbances on an industrial robot. The robot model used has three degrees of freedom, corresponding to the three main links on ABB:s IRB7600. The simulation environment is created using Matlab, Simulink, and Robotics Toolbox. It is constructed in a general way and can be used for simulations of other robot objects created in Robotics Toolbox. A gain scheduling is added to the LQ-regulator, where the feedback matrix is varied depending on the arm position in the workspace.

Efficient numerical methods for option pricing is an active field of research. This project has the goal to examine possible ways to improve an established method of numerical pricing. The method is based on an adaptive finite difference method in price and uses the backwards differentiation formula of order 2, BDF2, in time. The project will focus on improvements to the time integration through implementation of discontinuous Galerkin methods, dG. Empirical convergence and accuracy results are obtained for equidistant dG-methods up to order 3 and performance is compared to BDF2.

In the spring of 2014 Sweco Systems AB were commissioned to design a ventilation system for a newly built preschool in Linköping. Terms from the client was that it cost efficiency would cope with the energy demands that are placed on the building. The unit chosen was a cross-flow heat exchanger, and this work is to compare it with two other heat exchangers to see if a more energy and cost efficient could have been chosen. The heat exchangers that was chosen for the comparison was a rotating- and a counterflow heat exchanger. Simulations have been made to the different heat exchangers by the manufacturers.

This thesis gives an introduction to securitization in general and the tranching of collateralized debt obligations in particular. It does this by using a firm-value model to simulate the underlying portfolio via monte-carlo simulations.The simulations in turn give a loss-distribution from which the various tranchings of the CDO?s are derived. To get an understanding of the influence of different variables involved in the tranching the simulations are repeated several times where the portfolio variables are changed to generate different tranchings. This to give a understanding of the influence different variables have on the tranching and consequently risks involved in CDO?s in particular but also general risks and problems of securitizations..

In the spring of 2014 Sweco Systems AB were commissioned to design a ventilation system for a newly built preschool in Linköping. Terms from the client was that it cost efficiency would cope with the energy demands that are placed on the building. The unit chosen was a cross-flow heat exchanger, and this work is to compare it with two other heat exchangers to see if a more energy and cost efficient could have been chosen. The heat exchangers that was chosen for the comparison was a rotating- and a counterflow heat exchanger. Simulations have been made to the different heat exchangers by the manufacturers.

A numerical simulation case involving space plasma and the evolution of instabilities that generates very fast electrons, i.e. approximately at half of the speed of light, is used as a test bed for scientific visualisation techniques. A visualisation system was developed to provide interactive real-time animation and visualisation of the simulation results. The work focuses on two themes and the integration of them. The first theme is the storage and management of the large data sets produced.

Sparse matrices are often used in numerical algorithms that solve linear equation systems. Many methods for storing sparse matrices have been proposed and implemented during the years. These methods focus primarily on minimizing the total memory consumption and the time that it takes to store a sparse matrix. This report researches the available storage methods for sparse unstructured matrices. The formats that are researched and implemented are COO, CRS and ELL.

In this project we have used the theory of analytical mechanics to derive equations of motion for complex mechanical systems in order to study their behaviour over time. Even if the theory provides powerful tools to tackle tough problems which would be very hard to solve by methods of Newtonian mechanics, you are still relatively limited without running any computer simulations. One realises that in a faster rate it will be an incredibly difficult task to find an analytical solution when the degrees of freedom increases. Even if one would succeed to derive the equations, one still has to solve them to get the information of the systems behavior. Of experience one knows that the equations in general are nonlinear and hence must be integrated numericaly.

In this project we have used the theory of analytical mechanics to derive equations of motion for complex mechanical systems in order to study their behaviour over time. Even if the theory provides powerful tools to tackle tough problems which would be very hard to solve by methods of Newtonian mechanics, you are still relatively limited without running any computer simulations. One realises that in a faster rate it will be an incredibly difficult task to find an analytical solution when the degrees of freedom increases. Even if one would succeed to derive the equations, one still has to solve them to get the information of the systems behavior. Of experience one knows that the equations in general are nonlinear and hence must be integrated numericaly.

Sydkraft Vattenkraft AB owns and operates the Traryd hydropower plant, located in the river Lagan in the southern part of Sweden. The gravity dam is classed according to RIDAS guidelines (Hydropower Industry Dam Safety Guidelines) as a class 1B dam. This means that the dam must discharge a class 1-flow which has a return period of 10 000 years. The inflow into the dam has been calculated in an earlier report to 495 m3/s, with a waterline at an elevation of 126, 3 meters above sea level. The gravity dam has a discharge system with two rectangular weirs, which results in a smaller discharge than the necessary 495 m3/s.

The engine of JAS 39 Gripen, RM12, has recently been equipped with a new flameholder and a new engine inlet. This change has caused an increased noise level from the engine when the afterburner is in use. The noise level reaches its peak when the afterburner is partially used. The problem is thought to be unstable combustion in the regions around the flameholder. A solution to the problem has been proposed by Volvo Aero.

Studie är baserad på Siegler & Ramani (2008) ?Playing linear numerical board games promotes low-income child­ren´s numerical development?. Syfte är att undersöka om det med intensivträning (i form av ett linjärt tärningsspel) går att stimulera sexåriga barns talförståelse inom talområdet 1-10. Metoderna som valts är fältexperiment och observation. Fält­experimentet påvisar att intensivträning med ett tärningsspel, utfört under 4 stycken 15 minuters lektioner under en tvåveckors period, tydligt kan förbättra barns talförståelse medan observationen visar att utfallet påverkas av pedagogens olika yrkesverktyg samt undervis­ningens organisation (en-till-en undervisning).

This master thesis deals with problems in the arc length control in Pulsed MIG/MAG Welding. The main problem is that it is not possible to measure the arc length. In the present solution the voltage over both the electrode and the arc represents the arc length. To improve the arc length control a model of the electrode melting has been built. One output from the model is the voltage over the electrode and with this voltage together with the measured voltage it is possible to calculate the voltage over just the arc.