This thesis compares the impact on disk performance in a GNU/Linux  environmentwith three encryption algorithms: AES,  Serpent and Twofish in three different implementations: DM-crypt, Loop-AES and Truecrypt. For all three algorithms a key length of 256 bits is used.The thesis shows that the least performance impact during data encryption, and thus file writing, is reached by using AES or Twofish encryption implemented in DM-crypt or TrueCrypt. The thesis shows that some data operations with a sufficiently low processor utilization barely affects disk performance at all if encrypted using the optimal implementation and algorithm.It is also discovered that the performance impact during data decryption, or file reading, can be minimized by using the most efficient implementation and algorithm. The best results are met with the AES or Twofish cipher, regardless of implementation.An important conclusion that  is  drawn is that it is hard to determine a superior encryption solution for all purposes. However, by reviewing and examining the collected data from all aspects of disk performance the AES implementation in TrueCrypt is, with small marginals, determined to be the most optimal..

In this master thesis, control algoritms using arm side sensors are investigated for an industrial robot. The sensors can be position encoders placed after the gearbox and accelerometers on the robot arms. Control strategies are discussed and evaluated for different models of the robot, after which chosen strategies are applied to a realistic model. Control algoritms using arm side sensors (LQ, dual-loop and PD-PID) are compared to a PID-controller that only uses measurements of motor position for feedback control. The comparison are done with respect to disturbance rejection, oscillation damping, robustness and tracking performance of a reference trajectory.

Modeling and simulation is growing ever more important in the development of new products. This thesis describes the use of Hopsan for hydraulic modeling and its use in conjunction with Simulink with the intent of using the model in a hardware-in-the-loop setup. A sensor layer has been created in Simulink to emulate all the internal sensors in a modern forklift. The details of using legacy C-code instead of a hardware MCU for a fully simulated environment, software-in-the-loop has been outlined. There are two major routes one can follow implementing software-in-the-loop, exporting the C-functions to CAPL via a export layer or creating an s-function in Simulink.

This report treats two assignments that concerns the biofuel furnace at Billerud Skärblacka AB and how these assignments were solved. The assignments were: reducing the number of CO-spikes and tuning the overfire air control loop. To reduce the number of CO-spikes the possibility that skewness in mass distribution affects the number of CO-spikes were study. The skewnwss of mass distribution was controled and adjusted with two experiments. The conclusion that was made is that the skewness of mass distribution were not sufficient enough to affect the number of CO-spikes.

Det här examensarbetet presenterar en evaluering av en Klockkorrigerare av klockpulsbredd. Den består främst av en korrigerare av klockpulsbredd (Duty Cycle Corrector DCC) och även en fördröjningslåst loop (Delayed Locked Loop DLL). Det finns många olika korrigerare av klockpulsbredden designade förut, de två populäraste arkitekturerna då har varit enkel eller dubbel återkopplings loop. Den huvudsakliga skillnaden mellan dem är att enkel återkopplings loop använder sig av en öppen loop medan den dubbla varianten istället har en stängd loop. I det här projektet kommer en ny arkitektur att presenteras.

The purpose of this thesis was to help the company Medius AB with optimization of selected parts in an existing system to minimize the execution time by implementing multithreading. The idea was to manipulate the code so that calculations could be executed at the same time. The main work in this thesis consisted of three optimizations. The first one was to reconstruct a big ?for-loop? so it would execute every loop's work in an own thread. The second optimization also was a reconstruct of a ?for-loop? so it could execute the work in different threads. The third and last optimization consisted of reconstructing a stored procedure on the database, so different parts of it each could be executed in an own thread to create data at the same time. To implement the optimizations Visual Basic .NET and its support for multithreading and connection-pools was used. The result of the optimizations meant that one of the modules could be executed more efficiently and it was 12 % faster. The other modules execution time was more efficient by 25 % faster. The meanings and requirements for this thesis are fulfilled by now letting the system make use of its resources in a better way..

Första linjens ledares roll har under de senaste åren blivit mer ansvarskrävande. Vad är då viktigt för ledare i denna position då det kommer till att åstadkomma förändring? Finns det några utmaningar första linjens ledare stöter på? Denna studie syftar till att belysa första linjens ledares upplevelse av att leda en förändringsprocess. Två frågeställningar skapades; ?Vad anser första linjens ledare som viktigt i sitt ledarskap för att kunna åstadkomma förändring?? samt ?Vilka utmaningar möter första linjens ledare i en förändringsprocess??.

This report presents a master thesis project performed at Elekta AB during the fall of 2013 and early 2014. Elekta is a medical technology company and their main product in the Stockholm office is a gamma knife used for radiosurgery. The gamma knife contains a cluster of a dozen motor servos and motors used for adjusting the patient and the radiation sources over a CAN bus. A self-developed hardware-in-loop simulator running on a PC with LabVIEW is currently being used for integration level testing of the control system of the gamma knife. The simulator has some problems with it not running in real-time and having other performance issues.

This research analyzed differences in measurements of magnetic field strength and frequency response in five audio induction loops installed in rooms of wooden construction materials and five audio inductive loops installed in rooms of steel reinforced concrete constructions. The inductive loops were installed at floor level and the measurements were made at the listening height of 1.2m. Measurements of background noise, field strength and frequency response were made at fifteen different measurement points across the room. The research measurements showed that there are differences in field strength and frequency response between these two conditions, whether the audio induction loop is installed in a wooden construction or the audio induction loop is installed in a reinforced concrete construction. The results had a significance level of p=0,05..

Introduction: Reversal of a temporary loop-ileostomy is the final step after a long treatment for rectalcancer, an event that the patient has been looking forward to for a long time. Studies have shown that patients often have a significant impact on the bowel function after reversal of the stoma.Aim: To describe how the patient experienced the first time at home after reversal of a temporary loop-ileostomy due to rectalcancer. Method: Qualitative semi-structured interviews, with 15-20 patients who have undergone reversal of a temporary loop-ileostomy due to rectal cancer, will be conducted. The interviewes will be analysed using qualitative content analysis according to Graneheim & Lundman (2004). The patients will be recruited from the colorectal unit at Sahlgrenska University hospital/Östra and from the surgical unit at Kungälvs hospital.

Bakgrund: Med bakgrunden av företags behov att utvidga sin verksamhetssfär, har företagsförvärv blivit alltmer frekventa och mer omfattande. Speciellt i branscher med snabb utveckling såsom IT-branschen, är detta av aktualitet. Med förvärvsvågors uppkomst, har även ett stort antal av dessa förvärv resulterat i misslyckande snarare än expansion. Förklaringen till detta är mångfaldig och kopplas till områden kring före, under och efter förvärvet. Det som förväntas av ett förvärv, är synergieffekter, det vill säga förmågor av förvärvsobjektet som bidrar positivt till moderbolagets verksamhet.

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.

In this thesis, a computer program that in a simple way can calculate the performance of control loops at the refinery Preemraff Lysekil has been created. The computer program has been adapted to the environment at Preemraff Lysekil. Theories for evaluation has been studied in aspect of reliability and of automatic implementation. The evaluation has been carried out from data collected directly from control loops at the refinery and from simulated control loops with implemented errors. Among the studied methods are Harris index and Stattin´s oscillation index.

The aim of this research is to find out what environmental impact a wave power park has on the Swedish west coast by creating a consultation paper (?Samrådsunderlag?) for the Lysekilproject at Uppsala University. To highlight the complexity of the problem a system analytic approach was used and illustrated by a Causal Loop Diagram.The overall assessment of the Lysekilprojects wave power park at the Swedish west coast is that it will have a low impact on the environment. This is due to the relative small size of the wave power park and some technical solutions made with the environmental aspect in mind. Artificial reefs and a sanctuary for marine species are effects created by the wave power park and in the longer term the impact will give access to an untapped source of renewable energy, wave energy.

This study investigated the performance and cost of scarification with a tractormounted excavator. Due to variations in terrain conditions the performance variedbetween 0.08 and 0.11 ha/E15h and, with a machine cost of 366 SEK/h, the cost ofscarification varied between 3 330 and 4 750 SEK/ha..