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4058 Uppsatser om Dynamic model - Sida 1 av 271

Modellering av indunstning på Södra Cell Mönsterås

Evaporation is a part of the chemical recovery department at wood pulping mills. The purpose of evaporation is to remove water from the black liquor, which makes the liquor combustible. The process is very energy demanding, and having a well-functioning model of the system is of greatest interest. The model can then be used to study energy consumption and to test different control strategies. Two models have been developed during the master thesis.

Analys, modellering och återskapande av fordonsdynamiska rörelser i tåg

The purpose of this thesis was to analyse, model and finally generate dynamic vehicular motions in a train. The objective with the analysis was to find important motions for a realistic train experience. The motions from the analysis were then weighted against possibilities for generation in a motion platform.A dynamic motion model was created to model the selected motions. The model was implemented in a simulation environment, more specifically MATLAB/Simulink. The simulation environment was used to simulate the model and to generate outputs to control a motion platform.

Dynamisk modellering av VSC-HVDC : En statisk och dynamisk modelldesign o?ver VSC-HVDC fo?r implementering i ARISTO

This thesis treats the subject of a complete steady state and Dynamic model of the VSC-HVDC covering both the AC and DC system-side of the converter. The topology of the model is recreated after the scheduled transmission line in the south of Sweden, called SydVa?stla?nken. The topology covers both a simple two terminal connection as well as a multi-terminal one. This model is to be implemented in the power system simulation program ARISTO.

Value-at-Risk : Historisk simulering som konkurrenskraftig beräkningsmodell

Value-at-Risk (VaR) is among financial institutions a commonly used tool for measuring market risk. Several methods to calculate VaR exists and different implementations often results in different VaR forecasts. An interesting implementation is historical simulation, and the purpose of this thesis is to examine whether historical simulation with dynamic volatility updating is useful as a model to calculate VaR and how this differs in regard to type of asset or instrument. To carry out the investigation six different models are implemented, which then are tested for statistical accuracy through Christoffersens test. We find that incorporation of volatility updating into the historical simulation method in many cases improves the model.

Modellering av en panna med rörlig rost :  

The aim of this master thesis was to create a Dynamic model for the processes in a solid fuel boiler of the moving grate type. Another aim with the model was to keep it as simple as possible but still able to catch the dynamics of the processes in the bedplate of the boiler. The creation of the model had its origin from drying and combustion equations used in earlier modeling work of boilers. The represented model has been used to simulate different kinds of disturbances in a boiler and different ways to control the boiler. These tests show that controlling a number of parameters in the bed of the boiler is an effective way to keep the grate stable during disturbances.

Dynamisk investeringsstrategi på den svenska aktiemarknaden

The purpose of this paper is to investigate if a dynamic investment strategy on the Swedish asset market can accomplish better returns then a static investment strategy. The dynamic investment strategy is created by incorporating business cycle predictors and firm-level variables to predict future stock returns. The predictive regression is calculated wih 60 months of observation (1999 01-2005 12) and is then used to estimate future returns for 23 months in the period 2004 01 -2005 11. The structure of the regression, with linear functions of ? and ?, goes back to Shanken (1990) and Avramov and Chordia (2005) has had success with the variables chosen.

Prisstrategier : En studie om dynamisk prissättning på Major events

Purpose: The purpose of this Bachelor is to analyze how the organizers of a Major event price their tickets and how these strategies consistent and differs from dynamic pricing. The study also aims to analyze whether there are conditions for dynamic pricing in Major events in the future.Theories: Dynamic pricing - Kimes model, Segmentation, price discrimination, variable ticket pricing.Method: The study used a triangulation where a qualitative interview was combined with quantitative data collection. Primary data was collected through a qualitative approach through an interview with General Secretary Tony Wiréhn and Marketing Director Malin Eldh in the local organization of the IIHF World Championship in Sweden. The quantitative data collection was to collect price information from the games played in the Swedish side of the World Championship organization arrangements.Conclusion: The conclusions that can be drawn are that the organizer of Ice Hockey World Championships today largely applies segmentation and also the second and third degree price discrimination. World Cup organization believes that it has something they call "semi-dynamic pricing", which according to this study involves a variable pricing with dynamic tendencies, then prices on some games adapted based on supply and demand during the sales period.

Demonstrationsprojektets roll i framväxten av ny teknik: Fallstudier av två vindkraftprojekt

This report describes a synchronous machine model with magnetic saturation in d-axis, neutralconnection and electrical exciter interface for the transient simulator PSCAD/EMTDC. It hasbeen designed and verified in comparison to the regular machine model in EMTDC.The performance of the model is very good when incorporating a linear as well as a saturatedmagnetising inductance. The dynamic deviation is only thousandths to ten thousandths perunit. By using a cubic interpolation of the saturation curve, the model gives a good representationof the saturation effect. The open source code implementation of the synchronousmachine model gives the possibility to easily adapt the model to specific requirements.The derived model makes it possible to simulate a synchronous machine with its excitationsystems, e.g.

Adaptiv katalysatormodell för reglering

This master?s thesis describes the development of a model of the catalystsystem aiming at control by an MPC. A well functioning model, which is suitable in control purpose, is important while emission legislation become more and more hard to fulfill for the car manufacturers. Much research has been done in the field of physical modeling of the system, but in this work a linear adaptive time discrete ARX-model is developed and validated.The systems tendency to change its dynamic during usage implies that the model must be adaptive. The developed model proved to be well functioning and shows promising conditions for the MPC design.

Modell av en synkronmaskin för PSCAD/EMTDC med magnetisk mättning i d-led och elektriskt gränssnitt för fältmatare

This report describes a synchronous machine model with magnetic saturation in d-axis, neutralconnection and electrical exciter interface for the transient simulator PSCAD/EMTDC. It hasbeen designed and verified in comparison to the regular machine model in EMTDC.The performance of the model is very good when incorporating a linear as well as a saturatedmagnetising inductance. The dynamic deviation is only thousandths to ten thousandths perunit. By using a cubic interpolation of the saturation curve, the model gives a good representationof the saturation effect. The open source code implementation of the synchronousmachine model gives the possibility to easily adapt the model to specific requirements.The derived model makes it possible to simulate a synchronous machine with its excitationsystems, e.g.

The Swedish food retail market : An econometric analysis of the competition on local food retail markets

The Swedish food retail market contains of three major actors, ICA, KF and Axfood, all in all dominating 75 percent of the total market shares. The scant number of retailing actors indicates that the Swedish food retail market is a highly concentrated oligopoly, which as a fact has given rise to definite discussions and argumentations concerning the market situation. But is the food retail market imperfect and how do we reach a workable competition? Economic theory does not provide any clear answer on these questions, but is rather divided into two fundamentally different approaches to define competition: the static and the dynamic perspective on competition. In an attempt to examine the competition on local Swedish retail markets, the purpose of this study is to carry out an econometric model estimating the situation.

Utveckling av en dynamisk Simuleringsmodell av en skotare

The predominant forestry harvesting method is based on the harvester-forwarder method, theharvester folds, branches and cuts trees, and sorts the logs into piles, while a forwarder transportsthe logs to a landing area.This master thesis work is about realization of a dynamic forwarder simulation model, and itspurpose is to provide an integrated forwarder simulation model in MATLAB/SimMechanicswhere the forwarder is based on a concept using pendulum arms to connect wheels and chassis.Active suspension control is developed and implemented into the simulation model, and finallycompared in simulation with passive suspension.In a first step, an integrated forwarder simulation model is developed, containing a simplifiedforwarder model, a tire-to-ground interaction model and a test track model. The simplifiedforwarder model is based a rigid multi-body system with a spring-damper suspension of thependulum arms. The tire-to-ground interaction model calculates the reaction forces, friction fromthe ground and applies the propulsion force. The test track model is a simplified version of thereal test track in Skogforsk. The propulsion wheel torque control is used to regulate theforwarder speed.

Influence of the habitat on the potential for cannibalism and population dynamics in stream-dwelling European grayling (Thymallus thymallus L.)

Cannibalism can have major influence on fish population dynamics. A prerequisite for cannibalism is that the cannibal and the potential victim meet, and besides density effects, the encounter rate between cannibals and their victims is therefore also largely dependent on habitat use and habitat heterogeneity. In this study I quantified and compared the potential for cannibalism in stream-dwelling European grayling populations in three rivers in Jämtland by means of habitat classifications. I also analyzed population dynamic consequences of varying the potential for cannibalism in terms of intensity, using a physiological structured population model. Findings based on habitat characteristics were that the potential for cannibalism is in general not favourable in these types of streams.

Transferfunktionsmodeller modellering och prognoser av Sjötransportindex

We have by Statistics Sweden (SCB) been given the task of using different dynamic regression models in order to forecast service price index for sea transport. The aim is to see whether these models provide better forecasts than those previously used. This essay aim to identify, estimate and evaluate the selected prediction models. Through our data material we were given access to 28 sightings of sea transport index during the period of 2004 q1 to 2010 q4. We have chosen to evaluate three different transfer function models, one ARIMA model and one naive forecasting model. The input variables we decided to test in our transfer function models were the price of petroleum products, the port activity in Swedish ports and the lending rate of Swedish Central bank. The results of our study suggest that transfer function models generally provide better models than the ARIMA model and the naive forecast model.

Projekt Air Control

Dynamic Air Diffuser.

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