Simulation of different systems can be done using a graphical model description of the system based on block diagrams. The simulation software Matlab/Simulink offers a lot of possibilities to describe a huge number of systems, which can be linear as well as nonlinear. The simulation using Matlab/Simulink is done by integration based on different kinds of numerical methods.When nonlinear Simulink-models are simulated, it is often interesting to apply a Kalman filter to handle the noise that may occur within the process as well as corrupting the measurement. However, application of such a filter leads to an extensive time-consumption despite using fast computers. The reason is that the existing Matlab functions are not constructed for time optimal evaluation.

Webbaserat Tidrapporteringsystem.

The purpose with my degree project is to investigate the use of computers within the daily activity in three preschools and one preschool class. I have designed a survey that I distributed to the staff. The purpose of my work is to investigate how a number of preschool teachers and children in a few preschools and one preschool class in a medium-sized Swedish town are using the computer in their activities.My study shows that the computer is frequently used, both of the children and teachers, but also together. The children in my study are using the computer to play games, listen to music, and go into the websitewww.youtube.com, but also in order to write and count.  The teachers primarily use the computer to document, check their e-mail and listen to music.

The main purpose of this study is to investigate the unintentional learning that happens during the use of computer games. With the use of interviews with students in the ages 13-15 who all have played the game series Assassin?s Creed, and then compared them with students who does not play the game, we have been able to identify that some learning is taking place, but that the student?s attitude towards the subject, and their maturity, also is vital for the learning. Even tough, the students who didn?t really enjoy history as a subject showed better knowledge after playing the game, than the students who hadn?t played at all, which indicates that computer games can be a good source for learning.

At the department of Electronic Warfare Assessments at the Swedish Defence Research Agency in Linköping one of the activities is modelling and simulation of the duel between a robot and a target. The aim with this Master's thesis is to develop a simulation model of an hovering helicopter. First a theoretical description of the forces and moments acting on an helicopter is given. Then the equations of motion are derived. These equations are simplified to be valid only for a hovering helicopter and the result is a mathematical model.

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.

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.

This study investigates the effects that commercial computer games have on young individuals social comfort and learning progress. As a systematic study of literature, scholarly articles have been analysed in order to illuminate the positive as well as negative effects on social comfort and learning progress that may come with playing computer games. The social effects have mainly been discussed with role-playing games, such as World of Warcraft, as starting point, while the learning effects have been coupled with strategy games, such as Civilization IV. The study does not simply declare how these games can be good for these factors, but also in what respect computer games may prevent the development of young individuals socials skills and learning progress. The study showed that in spite of perpetual prejudices against computer games in the technological age, computer games might actually be good to use as a tool in order to authorize the development of young individuals regarding learning and social aspects.

The aim of this study is to investigate the prevalence of computer consumption among boys in ninth grade, and to see if there were any differences with regards to physical activity, sleeping habits, breakfast habits and BMI. The study has cross sectional design with a comparative and a quantitative structure and is based on a former study called ?Food & Health 2007?.  The respondents were represented by 181 boys in ninth grade, recruited from ten different schools in the county of Uppsala, who were answering questions about media consumption, breakfast habits, physical activity and sleeping habits. Daily computer consumption was reported up to one hour for 12 % of the respondents, one to three hours for 65 % and over three hours for 42 %. The boys who had a high physical activity level were less frequent in computer consumption while those who had a low physical activity level spent more time by the computer.

The aim of this thesis is to examine how teachers use computer based assessment in their work and what user barriers they experience while working with computer based assessments. The result of the thesis is meant to provide an understanding of which factors affect the use of computer based assessments and how a company who provide computer based assessments applications can increase the rate of use amongst teachers.To investigate this, the author examined a company in Sweden who provide a computer based assessment application for both universities and high schools. The study was carried out at two different schools, a university and a high school, both located in Stockholm. In total nine teachers were interviewed. The author also conducted observations at the company whose computer based assessment application was examined.The author?s findings suggest that a lack of functions within the application and lack of costumer support from the company all negatively impacted the teacher?s use of the application.

In recent years, existing solutions for cooling personal computer CPUs have been supplemented by a new product category, factory sealed water cooling loops. These systems, consisting of a water block with an integrated pump, a fan and a radiator, perform well compared to the air cooling solutions but are less effective than larger, custom-built water cooling systems.This project aims to explore the most important aspects of a factory sealed system and to identify possible cost-effective enhancements of the performance.The most significant differences between the different groups of water cooling loops are the block design and the pumping power. The performance of both categories is also largely dependent on the fan power, but increasing fan power has a large negative impact on the noise level.Both radiator size and fan model choice appear, in tests, to be relatively unimportant, presuming that the noise level is kept constant. The position and direction of the fan, however, has significant impact on both the temperature and the sound level.Water blocks can be designed in several different ways, both regarding the heatsink design and the flow direction. In simulation, flow with the inlet centered above the heatsink result in considerably lower pressure drop and slightly higher temperatures than flow through the block, for heatsinks with fin arrays.Creating a competitive product in this product segment certainly seems possible, as there are performance-increasing changes to be made that seemingly has little impact on the production cost.

A piezoelectric injector was modeled, in this Master Thesis Project which was carried out at Scania CV AB in Södertälje, in GT-Fuel. GT-Fuel is simulation program from Gamma Technology.The simulation model for the piezo injector was divided into a hydro-mechanical system and an electrical system (Piezoelectric element). First the hydro-mechanic model was duplicated from Advance Continuous Simulation Language model (ACSL). The simulation results were then compared to the ACSL, to verify that the hydro-mechanical system was modeled correctly. The simulation results for the electrical model were also compared with a Simulink model.

ITT Flygt is a world leading company that mainly manufactures submersible pumps. A problem of ITT Flygt is that product development projects rarely manage to hold the estimated project time. It shows that something unexpected occurs in projects quite often, which results in delays. The delays can both be due to an optimistic time plan of projects and risks in product development projects which are not discovered at an early stage. This added with unforeseen delays makes it difficult for ITT Flygt to estimate the duration of their projects.The goal with the Master thesis is to examine a suitable method for simulation of project time.

This thesis of 15 hp has been implemented at Halmstad University, in collaboration with Saab Dynamics in Linköping. Saab Dynamics is a company operating in the defence industry where competition is tough. This necessitates new ways to increase efficiency in the company, which is the basis for this thesis. Saab Dynamics wants to introduce simulation driven design. Since Saab Dynamics engineers have little experience of simulation, required a user methodology with clear guidelines.