This master thesis consists of the creation of shock absorber models for percussive rock drills. A model of the rock was also developed. These models were connected to existing models of the rock drill to create a complete simulation of the rock drilling process.When the models had been created the rock model was evaluated by comparison with measured values from lab tests. The verified rock model was then used to evaluate the shock absorber models.Four new shock absorber concepts have been developed. Three of these have been modelled, while the fourth have only been sketched and described.The evaluation of the models showed the following:? Simulations of the single shock absorber don?t correlate to reality very well.

Two ecological models of nitrogen processes in treatment wetlands have been evaluated and compared. These models have been implemented, simulated, and visualized in the Modelica language. The differences and similarities between the Modelica modeling environment used in this thesis and other environments or tools for ecological modeling have been evaluated. The modeling tools evaluated are PowerSim, Simile, Stella, the MathModelica Model Editor, and WEST. The evaluation and the analysis have been performed using McCall?s factors for software quality (McCall et al, 1977), a correlation analysis and the Constant Comparative Method (Glaser&Strauss, 1999).

Back in the 1950s Marilyn Monroe and her hourglass shaped body was the aesthetic ideal for how models were to look like. Nowadays, the tide has turned. Research has shown that female models are becoming increasingly taller, narrower and straighter. This trend has occurred despite the fact that both men and women (still) prefer medium sized women with curvy bodies. This essay examines if this trend can be justified from a marketer's perspective.

This study was performed in collaboration with Moelven Skog AB, Örebro district. The purpose of the study was to review existing literature in order to describe the current status of harvester based measurement technology as the way to provide information for calculating payment to the forest owners. In addition to this, a short survey was conducted to find out how a switch to harvester based measurement would affect the administrative workload on timber purchasers working for the district. The literature study shows that the harvester measurement technology is ready to use if it is combined with well-established routines for control of the harvesters, methods for automatic quality indexing of the timber and ways of creating pricelists specially adapted for harvester measurement. Pricing each stem seems to be the most promising method. Stem pricing has several benefits.

In this study a multiple linear regression was carried out in the interest of analysing a number of variables effect on the final prices of apartments in Stockholm?s inner districts. The result may be employed to predict and observe percentage changes on the final price of apartments in Stockholm in the future. Five models were constructed after which they were analysed and compared. The construction of these models were supported by data from the real estate agency Erik Olsson.

Introduction: Analysts worldwide valuates stocks and companies by using different valuation models. The models are used to calculate how much public company?s stocks are worth and to identify whether stocks are over- or undervalued.  Objective: The objective of this essay is to study which valuation models are mainly used by financial analysts in Swedish banks. The purpose is also to study how reliable these models are considered. Method: The empirical study is based on a qualitative approach through interviews with financial analysts. The study includes both primary data (interviews) and secondary data (literature, websites and scientific articles)Theory: The theory chapter includes methods of analysis (fundamental and technical analysis), Valuation models, components of valuation and an example of a valuation with the Discounted cash flow model. Empirical study: The study includes a qualitative research that consists of interviews with financial analysts.

The problems with train-induced vibrations are increasing with heavier and faster trains. Therefore the work with propagating vibrations is of outmost importance, and that is what this thesis relates to.To get a sensible idea of the propagation, calculation models are often used. Propagation calculation models takes into account factors such as distance to the railway, the ground material and the velocity and weight of the train. This work is mainly about finding suitable existing models and, if necessary, adjust them to be more useful with modern trains and railways.The report contains the work of adjusting one such model and does, despite the fully functional adjusted model, describe how much more there can be done within this topic. Finally, a few tips about specific areas that preferably should be studied to get even further knowledge about the troublesome problems from railways..

The aim and purpose of the following study is twofold. The first part aims at clarifying different models of migration policy available within research of political science. The second part of the study applies the identified models onto an analysis of the official report ?Integrationens svarta bok? and the suggestions the reports presents. The findings of the study are multiple.

Wind is used as an energy source all over the world. To be able to use this effectively, there is a need for as good forecasts and forecast models as possible. One of these models is Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS®) that is used to calculate short time forecasts. This model is used here to calculate wind speeds at two different areas in Västra Götaland, Bengtsfors and Vänersborg. There are also wind measurements with SODAR stations for these areas.

Today, activities funded with public funds needs to present relevant and reliable information which shows the results obtained. Requirements increase in welfare activities to be run based on scientific, empirical knowledge. This applies particularly to social work. The social work is, however, poorly researched in areas such as knowledge of interventions in the content, context and effects. One way to evidence-base social work can be to conduct regular and qualified assessments.

This paper describes a study examining four different GARCH models AR(1)-GARCH(1,1), AR(1)-EGARCH(1,1), AR(1)-APGARCH(1,1) and AR(1)-GJR-GARCH(1,1), and their ability to predict future volatility and thereby providing more reliable estimates for Value-at-Risk. The study is based on daily observations for the return of the OMX Stockholm 30 Index, during the time period 31st December 1996 to 29th December 2006. The coefficients for these GARCH models have been estimated using a five-year rolling estimation window, with one-year lags, for five different in-sample-periods. These five in-sample-periods, and the coefficients given by them, have been used to generate five out-of-sample predictions for the volatility in each year. Using these volatility predictions, the daily Value-at-Risk has been calculated for confidence intervals of 90 percent, 95 percent, and 99 percent, respectively, during the time period between 1st January 2001 and 29th December 2006.

This thesis studies the way valuation of investment properties is conducted in accordance with IAS 40 and how reliable these valuations are. This has been conducted by studying ten Swedish real estate companies listed on the NASDAQ OMX, during the period 2005-2008. The study shows that all companies use valuation models to determine the fair value of investment properties. Two different types of models have been identified. Companies that use the cash flow model show inconsistencies in time horizon, and how they determine the horizon value.

Previous work by researchers as Eugene F. Fama and Kenneth R. French, show that average return on stocks are related to a firms characteristics like size and book-to-market ratio. These kinds of patterns in average return is not explained by The Capital Asset Pricing Model (CAPM), and are therefore seen as anomalies. Fama and French have proposed a three-factor model, which captures patterns observed in U.S average returns associated with size and value.

This thesis has been a part of Forsmarks Kraftgrupp AB's evaluation of a turbulencemodel used in simulation of turbulent flow called PRNS (Partially Resolved NumericalSimulation). This model has promising properties and may be of use in savingcomputational resources. The purpose of this thesis was to analyze this model andcompare it with industrially applied models such as k-omega SST and LES (Large EddySimulations).PRNS works as a hybrid of the k-omega SST and DNS (Direct Numerical Simulation)where a constant, RCP (Resolution Control Parameter) with a value between 0 and 1are selected. This constant is then used in the calculations and determines thebehavior of the simulation. When RCP is set to zero the equation are the same as fora DNS simulation and when RCP is set to one the equations for k-omega SST issolved.

Because of new emission and on board diagnostics legislations, heavy truck manufacturers are facing new challenges when it comes to improving the engines and the control software. Accurate and real time executable engine models are essential in this work. One successful way of lowering the NOx emissions is to use Exhaust Gas Recirculation (EGR). The objective of this thesis is to create a mean value model for Scania's next generation EGR system consisting of a poppet valve and a two stage cooler. The model will be used to extend an existing mean value engine model.