Sök:

Sökresultat:

1429 Uppsatser om Non-linear models - Sida 4 av 96

Utbredning av markvibrationer och stomljud från järnväg : Undersökning och anpassning av beräkningsmodell

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..

Svensk invandringspolitik i förändring : En kritisk granskning av åtgärdsförslag inom SOU 2006:79 för en ny politik

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.

Utveckling och utvördering av statistiska metoder för att öka träffsäkerheten hos lokala vindprognoser

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.

Från top down till bottom up : - Att förklara och utvärdera psykosocialt arbete inom hälso- och sjukvården

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.

En empirisk studie av Value-at-Risk-prediktering med hjälp av GARCH-modeller

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.

Hur tillförlitlig är värderingen av förvaltningsfastigheter?: En studie av tillämpningen av IAS 40

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.

Modellbaserad ekoföljning i vätskefyllda tankar

This thesis discusses model based tracking of radar echoes in tanks with liquid content. The errors in the measurements are not always random in these cases, and the interference that occurs when nearby echoes moves in relation to each other makes tracking difficult. The tracking problem can be broken down to four parts; track initiation, track destruction, association of the measured echoes to the tracks and to update the tracks with the associated echoes. The radar measurement is primarily made on the surface. However, additional echoes from the tank floor or other structures and double bounces are normally present.

Analys av turbulensmodeller för CFD

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.

Värdering av prestation och riskbeteende i ung ålder : Finns det ett samband?

This paper is a study how students at a high school in Falun, Sweden, estimates theirperformance in an upcoming math test which is then compared with the actual grade thestudent performed. The students who participated also answered questions related to ?risksituations? to examine whether there is a correlation between how students estimate theirperformance in the context and their risk behavior, and if the students act like economicmodels assume. In agreement with previous studies, the boys in the survey tended to beoverconfident in their performance. The girls in the study were neither over- norunderconfident in her performance and no significant difference in the estimation of one'sperformance between the sexes could be proven.

Mean value modelling of a poppet valve EGR-system

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.

Digital 3d landskapsmodellering : detaljeringsgradens betydelse för läsbarheten hos digitala tredimensionella landskapsmodeller

In this paper I have sought a suitable level of abstraction in my models describing the landscape; the models are made to be viewed from eyelevel. Because of the spectator being ?in the model? the objects included need a certain degree of realism. I have sought what is needed in the model to be able to comprehend that the model is showing a landscape. Some details might be unnecessary.

How streaming media can be used in commercial mass
distribution

Mass distribution with techniques as multicast and peer-to-peer are becoming increasingly important in the Internet. Today the distribution of sound and video over Internet, so called streaming media, is static due to the unicast method. This results in a linear increase of distribution costs and therefore no conditions for commercial scalability. This thesis describes why multicast may be the only scalable alternative for commercial mass distribution of streaming media over Internet. Mass distribution through peer-to-peer technology promises a lot but is fronting a couple of great challenges, for example asymmetric bandwidth, locality and legalization.

Captr.net - Utveckling av iPhone-applikation och hemsida

Within the literature and film sciences there are clear models of storytelling and methods of creating a good story. In the game industry it's more difficult because the games are often non-linear, and games are a less established medium than the other two. With this study our purpose was to examine game developers and methods they used when creating a videogame, with focus on storytelling. Four interviews were made with representatives from four different videogame companies in Sweden. The information from the interviews was put in relation to theories regarding the structure of videogames and an established model for creating videogames.

Utvärdering av metoder och modeller för att simulera växlingskomfort i entreprenadfordon

Good comfort for the driver of a construction machine is crucial. Gearshift comfort is an important part of the total comfort. Volvo Construction Equipment Components has a simulation environment of the powertrain, SimPow, which is implemented in Matlab/Simulink. SimPow is mostly used for simulation of control strategies and performance. In order to be able to study gearshifting comfort, Volvo has an interest in developing new models for SimPow.

Den mångtydiga notbilden : Klingande gestaltning av pianostycken i romantisk stil utifrån instuderingar med reducerade notbilder

ENGLISH SUMMARYTitle:The ambiguous scorePresenting romantic piano pieces from simplified scoresIn this essay, I have investigated if different types of simplified scores ? scores whose musical structure are clearer compared to the original ? can stimulate a more artistic interpretation as well as a more linear understanding of the piece. My analysis also investigates what kind of impact these kinds of scores have on memorization.The music is derived from the romantic piano repertoire and the subjects are six university-level music students. Half of them were placed in a reference group, and only received the original scores, while the others also received the altered versions. I used both reduced scores where notes were removed in order to emphasize the linear structure and scores where the pitch notation was the same as in the original , but the notes were grouped differently.The result indicates that those having access to multiple versions had a positive impact on the musical interpretation.

<- Föregående sida 4 Nästa sida ->