The aim of this study was to develop a load prognosis model for Uppsala district heating system to be used as a tool for heat production optimization. The methodwas to build three models for the different customer types; housing, industry andoffices and then scale them for the total system using data from Uppsala districtheating system. The heat load consists of two parts, one that is temperaturedependent and one that is dependent of the social behavior of the customers. Thetemperature part was modelled with an ARX model using an outdoor temperatureprognosis as input signal. The social behavior part was modelled using the mean ofthe social behavior from some days before and additionally by distinguishing betweenweekdays and weekends.

In this final thesis two simulation models have been integrated. The simulation models are models of JAS 39 Gripen?s fuel system, software and hardware. The time consuming and costly work to develop software has made the department of fuel system to build two models in Xmath/Systembuild. The software model also simplifies the comprehension of how the software in the control computer of the fuel system works.

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.

This master thesis holds a modelling in Simulink for a physical model of a main battletank tower, a three-phase induction motor and some mechanics. The aim of this work is to connect an earlier project at AerotechTelub, named StabSim to another called Eldris. In StabSim it has been made a Simulink model of the align and stabilisation system in a main battle tank 122 and in Eldris it has been build a physical model of a main battle tank tower. In this thesis the models that differs between Eldris and a real tower is changed in StabSim, and the parts that only exist in Eldris is added, for example a torque generating system which purpose is to make the model to behave like a real tower in control application, although it only has half the inertia as a real tower. The thesis even includes proposing a calculation of the torque that the torque generating system will actuate at the model..

In order to evaluate the benefits and costs associated to investments in information technology (IT) managers need to be aware of the complexity in the nature of the task. Hence all the benefits that arise from the investment are not of pure economic character. The complexity of the task is even more obvious when managers also need to prioritize between a number of possible investments in order to fit a given budget.Stora Enso Skog AB is about to implement a new administration system to the organisation and due to that they will also implement a new standard system for the production planning process. In order to seek the modifications in the standard system that needs to be done to fit the organisations way of working, the managers have put together a reference group to seek out these modifications.The aim with this report is to identify a model that can prioritize these suggested modifications and test it practically with a group of future system users. The first part of the report is a literature study to map the existing models that are available.

The development in electronics increases the demand for good design methods and design tools in the field of electrical engeneering. To improve their design methods Ericsson Microwave Systems AB is interested in using computer tools to create a link between the specification and the implementation of a digital system in a FPGA. Xilinx System Generator for DSP is a tool for implementing a model of a digital signalprocessing algorithm in a Xilinx FPGA. To evaluate Xilinx System Generator two testcases has been designed. The testcases are selected to represent the FPGA designs made at Ericsson Microwave Systems.

The EU has decided that it should be possible for consumers to get information about the origin of the electricity they buy. Therefore, there is a need to examine different systems for electricity disclosure. In this thesis two ways of disclosure have been studied:? Certificate system. A certificate system involves two parallel markets, one for trading electrical energy and one for trading certificates of origin.? Separated Markets.

In system development it is today increasingly common to use a model-based system development method. These methods that are suited for Agile work with simple and quick updates and implementations of new applications in systems conform to the requirements that are becoming more important today, namely more flexible and less expensive system that still maintain high quality and safety.A company that has been working with this type of system development method for a long time is Genicore AB, which also has developed their own tools and model language in order to better model the information management systems in complex and abstract operations. Genicore AB is trying to spread their method other developers and have therefore taken the initiative to start this study. The method is evaluated and tested by two students with relatively little experience in model-based systems engineering in order to gain a new perspective on how the method functions. The method has been applied to an educational activity in order to test it in a new domain, and this led us to our research question;?What criteria are of particular relevance in the implementation of a MBSD method on on complex businesses??Through literature reviews and interviews, we formed an idea of how model-based system development works from a theoretical perspective, and then continued to the case study conducted on the educational activities at the faculty of IT at University of Gothenburg.

A cars powertrain consists of everything that is needed for its propulsion. The components in the driveline that transfer the power from the engine to the driven wheels are not absolutely stiff, hence they will wind up due to the torque and act as torsion springs. If you suddenly demand a bigger torque by stepping on the accelerator pedal, a so called tip in manoeuvre, and that torque is acquired from the engine as quickly as possible, the driveline will not be able to transfer that fast torque change due to its weakness and as a result it will start to oscillate. These oscillations will be transferred to the driven wheels and make the car to accelerate jerkily which will be experienced as uncomfortable by the passengers. Furthermore, there is a backlash in the driveline that will make the weakness in the driveline even more excited than it should have been if the backlash did not existed.To avoid too big problems with these oscillations there is a control system that controls the demanded torque.

The purpose of this thesis work was to develop an automatic fault detection system for surveillance of bearing temperature in hydropower turbines. The parameters used except the bearing temperature were cooling water temperature and cooling water flow. A simple static model based on data sampled every minute was developed to estimate the bearing temperature. Then a detector for detection of change in bearing temperature based on the CUSUM-algorithm was designed. Since the amount of data was very small the developed model was too uncertain to be used in a working system.The designed fault detection system showed to work well for the available data.

The work with this report has been focused on developing a methodology model for control at purchase. The methodology model covers parts classification, dispatching systems, batch shaping and more. The aim with the methodology model is that it will be used as an aid for a cost effective material planning to increase the value for customer.The work covers also a description of the present situation and the purchase process at Company X. Six parts have been applied, two from each class (A, B and C), in the methodology/model. The parts that have been applied are included in the flow between Company X and their supplier Company Y.Data have been collected trough literature studies, interviews and the company?s business system.

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 master thesis covers the seasonal planning of a small scale hydropower system. The system in this study is owned and operated by Mälarenergi Vattenkraft AB. The total system consists of 4 different main rivers with 24 hydropower stations and several dams. The total installed power in the system is 43.75 MW. Most of the hydropower stations are regarded as small scale hydropower stations and thus entitled to green certificates.In this report the issue of planning is formulated as an optimization problem.

Abstract The purpose of writing this thesis was to improve methods during requirements engineering phase. Usercentred system engineering has some problem areas, which are examined and verified to create a new guideline for developers. This guideline tends to make requirements engineering more effective and help developers create more concrete requirements. It is not uncommon that system development projects ends up with unsatisfied users or delay in deliveries. The reasons are different kinds of communication problems between users and developers during verification of requirements.

The aim of this thesis is to develop a new business model for district heating and cooling firms which can contribute to a stabilization of the Swedish national energy system. The business model is developed for a district heating and cooling firm and is exemplified with Fortum Heat. The theoretical investigation around the topic creates a rigid base for following qualitative empirical studies. Osterwalder?s canvas for business model generation is used together with a Casual Loop Diagram to identify a number of business opportunities which stabilizes the national energy system.