Historically transformers with system earth equipment have been modeled as open circuits in zero sequence. This approximation has been satisfying, but lately it has been discovered that equipment on one side of the transformer have responded to faults that occurred at the other side. Most of these problems took place when the majority of the system on the secondary side of the transformer contained cables. These findings have led to questioning whether or not the former model of the transformer in zero sequence is correct. This report investigates if it is necessary to represent the transformer in zero sequence in another way than it is usually done today.

Den här rapporten är ett resultat av ett kandidatarbete på 20-poäng. Projektet som rapporten handlar om, beskriver hur utvecklingen av ett webbutikssystem åt ett flertal företag gått till. De har i sin tur köpt webbsystemet från företaget Opti Use som givit oss uppgiften. I rapporten diskuteras hur utvecklingsprocessen gått till och hur ett arbete med ett befintligt system upplevts. Rapporten beskriver även hur lösningen på uppgiften har tagit form och hur utvecklingsprocessen påverkat den.

The purpose of this study was to investigate the possibility of streamlining the test process by utilizing pair programming. During the process, pair programming has been practiced as is defined by the Extreme programming (XP) software development methodology, with the other aspects of XP discarded. The focus of the testing itself has been toward unit testing. The methods applied has been with an experimental approach where 93 cases were attempted to be solved by either single programmers or pair programmers. What has been investigated in these experiments was the time needed to complete a case, how many test attempts were needed to solve the case, and how high a percentage of the cases were solved.

The company Sound Precision has developed a new Line Array loudspeaker system (VHA-40). When using this system, their customers need computer aid to get the best possible sound-quality and control of sound levels for the whole audience. The aim of this thesis is to develop a truly useful sound quality simulator for the VHA-40. The system will help the sound engineers to position the loudspeakers for optimal sound by simulating loudspeaker configurations and visualizing the resulting sound quality and quantity. To solve this a human-centered design (HCD) approach is taken to implement a system that is truly useful for the users, meaning that they will use it more and hence deliver better sound for the audience.

This paper aim to present a model for evaluating what we choose to call HTML-frameworks, a framework that contains a set of CSS layouts and occasionally JavaScript support, based on the characteristics of the software quality standard ISO/IEC 9126-1. The methods used to produce this model is based on a field study that involved making a web portal with the help of a HTML-framework, some relevant literature and an analysis of the framework based on the characteristics of the ISO/IEC 9126-1 standard. The result was a model based on twelve different characteristics; functionality, web browser compatibility, collaborative skills, user-friendliness, documentation, visuals, graphic layout, performance, activity, professional support, replaceability and license. This model should be viewed upon as a suggestion to what a model for choosing HTML-framework could look like, because we haven?t had the time to test it in a real situation, so further studies are needed, and we believe there could be improvements made in the objectivity of the assessments of the characteristics..

The company Sound Precision has developed a new Line Array loudspeaker system (VHA-40). When using this system, their customers need computer aid to get the best possible sound-quality and control of sound levels for the whole audience. The aim of this thesis is to develop a truly useful sound quality simulator for the VHA-40. The system will help the sound engineers to position the loudspeakers for optimal sound by simulating loudspeaker configurations and visualizing the resulting sound quality and quantity. To solve this a human-centered design (HCD) approach is taken to implement a system that is truly useful for the users, meaning that they will use it more and hence deliver better sound for the audience.

Through a case study, I wanted to find out what advantages and disadvantages local companies consider with scrum and what they think about its future. To find out what scrum is, I read the literature and scientific articles and then wrote surveys based on my thoughts. Further, I also wanted to find out if it?s possible to use scrum in a school environment and therefore I visited a high school class who used scrum in one of their projects. The result was good but could have been better as it requires more training of scrum to understand everything.

We are surrounded by sounds. There is always something that makes a sound: a breeze through the leaves, traffic on a distance or your own blood rushing through your veins. Human will always be surrounded by sounds which makes it an important part of our lives. Therefore the sound should have a big influence on how we perceive our surroundings and interpret our world. This essay inquires into what sounds can mean to an open space and urban spaces.

This report is about Adobe Acrobat 3D and their new PDF format witch can contain 3 dimensional models that are interactive. The purpose is to find out if the program and the format work in a level that is suitable for the market. To create this PDF you need Acrobat 3D installed on your computer but it only needs Acrobat Reader 7 or 8 to open it, and the Reader is free to download on the internet.The examination is focusing on four formats: U3D, 3DS, DWG and DXF because they are the most common in the building industry seen from the architects? way. From a 3D model exported to these four formats they where converted to PDF in different settings to be compared in different points as information and size of the files.

The Swedish State Road Administration has since 1992 procured operations and maintenance of state roads on the open market. The procurement has been termed ?Grundpaket Drift?, GPD, and comprises mostly operational measures for road networks.The clients of GPD, SRA regions, have gradually changed the original documentation in order to adapt it to local conditions. This process has gradually led to that some parts of the documentation are creating problems for contractors interested in procuring jobs.This thesis tries to analyze GPD and clarify the differences that may be essential to the procurement process and to facilitate future joint working projects and processing descriptions..

The paper, with a brief summary of timber floating in Sweden and also of some previous re-search in this field, contains a study on costs for timber-floating in the river Dalälven located in central Sweden. The public used timber-floating system in Dalälven and the historical background about this activity is described. The study is focused on the total costs for timber-floating in the public open floating system in Dalälven from 1900 to 1970, the year before the timber-floating was definitively closed down. Also the costs for separating the logs of a specific owner when they reached the point where they could be separated from the timber of other owners are analyzed..

A substation must be properly protected against lightning and other external effects to the equipment in the station or staff, for that we use relay protection. They should also protect against internal errors which may occur as ground faults. There are different types of protection relays, but most common are overcurrent-, distance-, residual current- and differential protection.The purpose of this thesis was to deepen our knowledge of relay protection and to use the theoretical knowledge we got from the university studies in the work process. In the process we discovered which parameters were the most essential and calculated these for all relay protections on the substation. We also carry out a comparison between two brands of relay protection, ABB and Alstom.During our work we will test and simulate the over-current relays in a program called NEPLAN, the program will also calculate the fault currents.

In today?s business environment, cost-cutting practices such as downsizing and layoffs remains a widespread phenomenon. Although, the understanding of the effects that these practices has on the remaining individuals, defined as the survivors, is poor. The focus in this paper is therefore to examine how survivors of layoffs can be affected on an individual level, and by what causes.The study was conducted using open-ended, qualitative interviews with three individuals with different experiences of layoffs. The empirical data was analyzed by extracting quotations from the interviews.The study found that layoffs affected the morale and attitude towards management of the individual, and that perceived justice and uncertainty are two causes of negative effects from layoffs..

The author of this report has created a Web-based invoice system and CRM at therequest of the company Webhouse.se. The purpose of the System is to makeeveryday tasks in the company easier. The system also needed to prevent mistakesand errors by managing orders and invoices.The system has been created with the company?s requests in focus. During thedevelopment of the system information security and interaction design have beenimportant aspects that have been taken into consideration.The system has been created using techniques such as PHP and MYSQL.

This essay is written at the university of Linköping and is a part of the teachers education. The intire essay is available on CD-rom. Its content is directed towards teachers who entirely or partly works, or want to work, in computereducation. The CD-rom contains both textmaterial and presentations, with teacherinstructions, wich are directly appliable in teaching computers. The teachingmaterial on the CD-rom is based on an empiric survey with different computerteachers.