The aim of this paper is to find an algorithm to establish and maintain a virtual enclosure around a mobile unit. The area may take any form and should be scalable up to and including national borders. The enclosure is managed on the mobile unit. The target system is Android. Smartphones, tablets and more recently, cameras is examples of mobile units. A modern mobile unit is part of a computer network.

The purpose of this thesis is to give an understanding of how grocery stores relate to local foods. Through a case study representatives for two groceries in Norrbotten have been interviewed regarding why they supply local foods, how they try to influence customers to buy this, and how they decide upon the assortment of local foods. The result shows that groceries supply local foods in order to supply a wide range of products and to mediate social responsibility, in order to create customer loyalty. Concerning how the groceries try to influence customers to buy local foods the result cannot give any clear-cut view. Instead it shows that a grocery that actively works to influence customers to buy local foods markets them in specific ways, while the opposite applies to a grocery that does not actively work for this.

With background in the rapidly growing need to find solutions for sustainable energy production and the increasing interest for wind power, this report was written. With take-off point from the wind power plant Big Glenn, which has been built in the harbour of Gothenburg, a model of the adjacent power grid has been created in Simulink/SimPowerSystems. Parameters for the power grid and its components has been provided by Göteborg Energi Nät, that has also been the supplier of measurement data of produced power, the power need from loads in the vicinity, voltage levels, current values and also the variation of power factor at the wind power plant.The SimPowerSystems model has been used to perform simulations of power flow in the grid. These simulated values have then been compared to the measured values to verify the functionality of the model. Further, the model has been used to perform simulations of a grid fault, which causes a voltage drop.

The technological legacy from the early electrification of the Swedish railroads has resulted in a power grid with a lower grid frequency than the national power grid from which it is fed. Energy transfer between these power grids with different frequencies requires substations, adapting the grid frequency for the rail road power grid. For this purpose, a feeding power grid has been built, stretching across the country from Boden in the north to Tälle/Häggvik in the south.Power transfer in the Swedish power grid results in voltage angle differences which increase with increasing loads and transfer distance. These voltage angle differences are transferred from the power feeding substations to the rail road power grid, will in some extent cause loss of energy due to unwanted power flows from north to south.To minimize the losses due to this phenomenon, a power management system called EFS 132 kV has been developed and implemented. The system minimizes the unwanted power flows and controls the desired power flow for a good distribution of loads between the power feeding substations.This thesis investigates the extent of the transmission losses avoided due to the EFS 132 kV that coordinates the idling angles to a common reference point.The results indicate that EFS 132 kV affects the power flow, especially between the northern substations through an improved load distribution.

This study aims at using discourse analysis to analyze SFI students attitudes to religion and religiosity in an SFI-context. The questions are: How is the discourse constructed and maintained by religion and religiosity of SFI students in an SFI context? How do SFI participants experience that their religion has affected their time at SFI?Using a case study approach, interviews were conducted with a group of SFI students. The results show that the religious discourse in SFI is influenced by the SFI-context and affected based on the current education discourse that exists there. Furthermore, the discourse is designed and maintained by the participants private religious beliefs and the religion of the majority of the group, One canhere speak of a strong social unit forming a plausibility structure The power structure that emerges is that the majority has the power to define the significance of religion and place within the SFI context. In the SFI-context the participants view is that religion is something private that should not be expressed in the school environment.

Orust Kretsloppsakademi is a nonprofit organisation, with a goal of annually generate the same amount of electrical energy that is consumed. Orust is an island on the west coast of Sweden, north of Gothenburg. The population of 15 000 reaches 40 000 during summer, due to the large amount of vacationer. The total electricity demand is 174 GWh a year with a maximum power need of 32 MW. This report presents an analysis for the plausibility of their plan and from a power system stability perspective, the effects on the electrical grid.The conclusion is that the restraints for development of power generation from wind, solar and wave generation, are the power systems capability to transfer power, primarily in the transformers of the grid.

Background: The strategic importance of purchasing departments is increasing, yet supply risks are rather uncharted. The procurement of coffee involves supply risks and the purchaser needs to be able to handle these to enable the roasting-house to produce coffee as specified. Purpose: To chart risks in connection with the procurement of coffee as well as the possibilities of handling these. The thesis also examines if general risk management theories are applicable on the supply risk present within Swedish roasting-houses and can become an integral partof the purchasing process. Method: A qualitative case study of the purchasing process of Swedish roasting- houses.

In hydropower plants it is necessary to always have local power supply. Therefore, the plants are equipped with batteries as stationary back up power. Vattenfall Vattenkraft is using lead acid batteries but has been investigating alternatives to replace them. The aim of this study is to investigate the potential of using Li-ion technology as back up power.The study showed that Li-ion batteries have many qualities. The Li-ion technology will decrease the space and maintenance demand.

Today?s wind power plants are only compensated for their reactive power consumption at no-load. As the wind power plants grow bigger the amount of reactive power they need also increases. This is no longer a problem that can be ignored, especially as the net owners are beginning to charge the reactive power they transport.In this thesis a couple of different methods of compensation and their prices will be discussed and evaluated. Problems, such as self-excitation, that can occur if one fully compensates the wind power plant will also be brought to surface.

Today?s wind power plants are only compensated for their reactive power consumption at no-load. As the wind power plants grow bigger the amount of reactive power they need also increases. This is no longer a problem that can be ignored, especially as the net owners are beginning to charge the reactive power they transport.In this thesis a couple of different methods of compensation and their prices will be discussed and evaluated. Problems, such as self-excitation, that can occur if one fully compensates the wind power plant will also be brought to surface.

In this paper I study how the repeal of the Swedish wealth tax (1 of January 2007) has affected people´s labour supply behaviour. This particular issue is relevant because it may help us understand some of the effects of the earnings tax changes that have taken place in Sweden. Accoring to standard economic theory a repealed wealth tax is similar to an income effect for the persons who previously paid the tax. That means that they theoretically will want to consume more leisure, that is decrease their labour supply. The method I am using to test this hypothesis is a difference-in-difference approach where the treatment group consists of persons who previously paid the tax and the control group of comparable persons who did not pay the tax.

Supply Chain Management innebär styrande av leveranskedjor. En leveranskedja består av leverantörer, tillverkare, distributörer och återförsäljare. I dagsläget bör marknadskonkurrensen vara mellan olika leveranskedjor och inte företag mot företag.För att erhålla konkurrenskraftiga leveranskedjor krävs det bland annat att företagen nyttjar kommunikation tvärs genom hela leveranskedjan, samt att företagen använder de tekniska hjälpmedel som finns för att förenkla det administrativa arbetet.En förutsättning för att leveranskedjan skall bli konkurrenskraftig är att företagen som ingår i kedjan vågar delta i informations- och kunskapsutbyte. Med ett sådant utbyte bör företagen höja värdet på slutprodukten till ett reducerat pris.Syftet med rapporten är att sammanställa en modell över "hur den undersökta kedjans informationsutbyte äger rum idag".Den undersökta Supply Chain Management-kedjan har kommit en bit på väg, men nyttjar i dagsläget inte Supply Chain Management-filosofins alla konkurrensfördelar. Företagen använder sig bland annat av lager för att tillmötesgå sina kunders krav på snabba leveranser..

The purpose of this degree project was to build laboratory equipment for a new course in power electronics that starts this autumn 2010 at Uppsala University. The equipment is intended for student labs and it covers the most important areas of the course including rectifying, buck-/boost-converters and PWM-modulation. It is built as one sealed unit where all the electronics are built-in but visible and it has a connection board where students safely can connect the different circuits. The project has advanced from theoretical studies of circuit design, choosing of components and simulations to drawing the printed circuit board (PCB), soldering, case building, final testing and troubleshooting - basically most steps from an early idea to a final product. Measurements on the final product gave about the same results as the earlier simulations of the circuits and the result is overall satisfying..

In today?s society there is an increasing demand for renewable energy sources such as sun and wind power. These sources are intermittent, and energy storage is therefore needed to ensure a constant power supply. This report compares pumped hydro energy storage (PHES), compressed air energy storage (CAES), flywheels, batteries, super magnetic energy storage (SMES) and hydrogen energy storage.The opportunities for further development are limited for PHES and CAES in comparison with the other technologies. Lithium-ion batteries and hydrogen energy storage are considered to have the most potential in the future.

The debate on the future of Nuclear power in Sweden has increased with the discussion on global warming. The uncertainty of fossil fuel- and carbonprices the latest years has aroused considerable interest in Nuclear from power companies, industry and politicians. Nuclear power plants have negligible CO2 emissions and are not directly affected by increased price of emission rights and fossil fuels. The future power production needs to reduce its emissions of greenhouse gases to become sustainable. The purpose of this study is to examine the value for power producers to have the option to invest in Nuclear power and how a Nuclear power venture would affect future electricity prices. The study uses two methods, a traditional cash flow model and real option analysis, to estimate the value of Nuclear power.