This thesis discusses model based tracking of radar echoes in tanks with liquid content. The errors in the measurements are not always random in these cases, and the interference that occurs when nearby echoes moves in relation to each other makes tracking difficult. The tracking problem can be broken down to four parts; track initiation, track destruction, association of the measured echoes to the tracks and to update the tracks with the associated echoes. The radar measurement is primarily made on the surface. However, additional echoes from the tank floor or other structures and double bounces are normally present.

Den obemannade  helikoptern Skeldar utvecklas av Saab Aeronautics. Saab är intresserade av hur väl sensorfusion kan användas för navigering av en obemannad helikopter. Med sensorfusion kan tillgängliga sensordata fusioneras. Det är mätningar från accelerometer, gyro, GPS och magnetometer som används av olika Kalmanfilter. Olika sensorfusionsmetoder föreslås, däribland Extended Kalman Filter (EKF) och ett heuristiskt filter för att visa på hur man intuitivt kan göra för att fusionera mätningar jämfört med det modellbaserade sättet som Kalmanfiltret erbjuder.

This thesis describes a method of measuring axial magnetic leakage flux in an operational hydropower generator. Axial magnetic leakage flux is the magnetic flux at the ends of a rotating generator, which goes through the stator parallel to the rotor axis. This flux can cause circulating currents in the stator iron, giving rise to losses, and can in the worst case overheat a generator, causing it to melt down. To measure the axial flux, and how it affects the generator temperature, a measurement system was constructed on behalf of Vattenfall. The system consists of search coil sensors and a signal-processing unit with amplifiers and active filtering.  To confirm the behaviour of the axial leakage flux and the functionality of the measurement system, a test installation was made.

Friend lists allow Facebook users to group their friends and may be used to share certain information only with those in a specific list. This function has been around for several years, but has never gained any particular popularity among users, most of whom probably did not know it even existed a couple of years ago. In the fall of 2011, however, the function was updated and made more visible on the site.There are several possible uses of friend lists, such as privacy control, filtering of the news feed, self-presentation and targeted information sharing. This paper aims to investigate the extent to which friend lists are used by students today, as well as why students actually use their lists, i.e. for what purposes.Judging from the results of this study in comparison with earlier research, there seems to have been a somewhat recent increase in the awareness of the fact that friend lists actually do exist, but still most users tend not to utilize them.

This report discusses a method to detect divers in harbour environments usingpassive acoustic detection. The goal was to achieve as high detection as possiblewithout having too high false alarm rate. A short execution time was also desirable.By using the characteristic of an inhalation a band-pass filter was applied to the signalto improve the signal to noise ratio. After the filtering an energy estimation of thesignal was made. This energy estimation was later used in a frequency analysis, whichcould tell us if there were enough energy in the frequencies that correspond to adivers breathing frequency.

Skuggor i 3D-miljöer är ett mycket efterforskat område, och detta arbete koncentrerar sig på shadow map-algoritmen. Det finns ett problem med denna algoritm, för då en shadow map projiceras på en yta som är större än sig själv så bildas stora trappstegseffekter, vilket kallas aliasing. Problemet som har undersökts är hur olika shadow map-algoritmer i en miljö med långa skuggor beter sig, där ett minimerat antal artefakter så som brus och aliasing är synligt. För detta undersöktes Percentage-Closer Filtering (PCF), som är en variant av shadow map, med olika samplingstekniker ? och även en vidarebyggnad med Percentage-Closer Soft Shadow (PCSS) implementerades.

This report discusses a method to detect divers in harbour environments usingpassive acoustic detection. The goal was to achieve as high detection as possiblewithout having too high false alarm rate. A short execution time was also desirable.By using the characteristic of an inhalation a band-pass filter was applied to the signalto improve the signal to noise ratio. After the filtering an energy estimation of thesignal was made. This energy estimation was later used in a frequency analysis, whichcould tell us if there were enough energy in the frequencies that correspond to adivers breathing frequency.

Informationsso?kningar av olika slag sker dagligen va?rlden o?ver och so?kresultatet kan ma?nga ga?nger vara sa? stort att anva?ndarna har sva?rt att veta vilka so?kresultat som a?r relevanta. I denna uppsats har syftet varit att underso?ka hur so?kresultat kan filtreras och sorteras med hja?lp av platsbaserad so?kning fo?r att det ska bli mer relevant fo?r anva?ndaren. Genom litteraturstudie och intervjuer har det blivit mo?jligt att ta reda pa? hur ett so?kresultat skulle kunna filtreras och sorteras fo?r att mo?ta anva?ndarnas fo?rva?ntningar.

This master thesis includes a description of how a number of sensors are put together in a sensor platform. It also gives a description of how localization and mapping has been performed with data collected from the sensor platform. Localization is a prerequisite for most of the tasks that can be requested from an autonomous mobile robot. In many situations the GPS signal is not available and hence an additional localization system is required. One approach is to apply localization based on landmarks extracted from the robots surrounding.

SammanfattningDenna uppsats beskriver design och implementering av en mer effektiv metod att styrakameraförsedda radiostyrda markfordon (UGV av engelskans Unmanned GroundVehicle). Det åstadkoms genom att införa samma kontroller som är vanliga i actionspel iförsta persons perspektiv, så kallat Free Look Control (FLC). Miljontals spelare kommeratt känna igen och vara bekväma med styrprincipen, vilket borde reducera dengenomsnittliga träningstiden samt förbättra prestationsförmågan. FLC gör det möjligt föroperatören att kontrollera kamerans läge direkt istället för via fordonet den sitter på.Detta görs genom att i mjukvara sammankoppla fordonets och kamerans rörelser.Utöver författandet av denna uppsats byggs en fungerande UGV-prototyp som kanstyras enligt både FLC och dagens standard, Tank Control (TC). Detta gör det lätt attdemonstrera skillnader mellan metoderna.Arbetet utförs åt institutionen Flyg- och systemteknik inom FOI, Totalförsvaretsforskningsinstitut, för att demonstrera och marknadsföra konceptet att använda FLC förstyrning av obemannade markfordon.Nyckelord: Odometri, Kalman filter, UGV, Unmanned Ground Vehicle, obemannademarkfordon, FLC, Free Look Control, FPS, First Person Shooter, fjärrstyrning..

Dynamiken för en starkt accelerande robot har modellerats. Modellen linjäriseras så att roboten beskrivs som ett linjärt tidsvariabelt system. Denna representation beskriver roboten väl då robotens anblåsningsvinkel, vilket är vinkeln mellan robotkroppen och robotens hastighet, är liten. Eftersom det ej är möjligt att mäta alla robotens tillstånd har en observatör tagits fram i form av ett Kalmanfilter. Problematik vid framtagandet av observatören diskuteras i rapporten.

Driveability analysis of terrain data offers an important technique for decision support for all kinds of movements in the terrain. The work described in this report uses a high resolution digital terrain model generated from the laser radar data and further processed by the Category Viewer program, and information from the Real Estate Map. Properties of features found in a filtering process are calculated and compared with a set of rules in a knowledge base to get a driveability cost. This cost is then visualized in a graphical user interface. An evaluation of what driveability is and what it is affected by is performed, and a general cost function is developed, which can be used even if not all relevant information is available.

The goal of this project was to create a web-based, crowd-sourced, correlational database, that easily allowed users to submit objects and receive correlated objects as results. The webservice was created in the web development languages of HTML, CSS, PHP and Javscript, with MySQL to handle the database. Simultaneous development was kept in check with the aid of the source code management system GIT. Upon completion, the service contained several HTML-views, the ability to add and rate objects, a per-object dedicated page with information parsed from Wikipedia.org, and a view with objects ranked in accordance to the preferences specific to the current user. Roughly a month after the beginning of development, the website was publicly launched and promoted in order to collect data, and improvements were added to the website as needed.

The number of blogs, from weblogs, are increasing every day. Blogs are also becoming more visible in the public debate as well as the awareness of their existance is rising among politicians and citizens. The aim of this thesis is to answer the question what democratic potential blogs can have. This question will be answered by initially studying the research that exists today about weblogs and democracy. The second part of the analysis consists of a selection of texts from weblogs that touches this subject.

During test flights SAAB uses the data acquisition system COMET 16. The part of the system that receives the signals from the sensors and converts them is called KSM 15. The purpose of this thesis is to develop a data acquisition module on stacked PC/104 modules with a lower production cost. Our work has been divided into one part about analog signal conditioning and a second part with digital filtering and memory management of the sampled data. The analog part, designed of regular components like instrument amplifiers, voltage references, operational amplifiers and multiplexers, adjusts the sensors signal levels for the ADC?s that converts the signals.