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25 Uppsatser om Rotational symmetries - Sida 1 av 2

Detection of interesting areas in images by using convexity and rotational symmetries

There are several methods avaliable to find areas of interest, but most fail at detecting such areas in cluttered scenes. In this paper two methods will be presented and tested in a qualitative perspective. The first is the darg operator, which is used to detect three dimensional convex or concave objects by calculating the derivative of the argument of the gradient in one direction of four rotated versions. The four versions are thereafter added together in their original orientation. A multi scale version is recommended to avoid the problem that the standard deviation of the Gaussians, combined with the derivatives, controls the scale of the object, which is detected.

Utveckling av en matematiklaboration på Vetenskapens hus : En tillämpning av gruppteori på molekylär symmetri

This master thesis is the documented work of the construction process and testing of a three hour laboratory session in mathematics aimed at high school level students. The purpose of the thesis was to create an interesting laboratory session for the science education center ?The House of Science? that could be used as a part of their regular program directed to schools. The thesis explores the possibilities for how one can construct a laboratory session on the topic ?molecular symmetry? as well as the underlying pedagogical theories used to describe learning processes in creative contexts.

Optisk undersökning av dieselsprayer från en höghastighetsroterande insprutare

There have been changes in Earth?s climate system on both global and regional scale since the pre-industrial era and some of these changes are due to human activities such as the combustion of fossil fuels. This calls for the development of engines with a higher efficiency and less harmful emissions. One interesting concept is the Homogeneous Charge Compression Ignition (HCCI) engine, which has the advantages of potentially low emissions combined with high efficiency. However, HCCI with diesel fuel requires a relatively long fuel/air mixing time to ensure a "homogenous" charge.

Betesdrift vid automatisk mjölkning i ekologisk produktion :

An automatic milking (AM) system should be combined with some form of controlled cow traffic to minimize the time spend on fetching cows to milking and to increase the milking frequency. By restricting the hours spent on pasture per day you optimise the AM system use during pasture period. A reason for this is becuase cows do not return to the stable for milking during night which cause that the milking unit stands empty those hours. In organic production it is required that the cows should be able to graze a certain amount of daily dry matter (DM) intake on the pasture. In the county of Dalarna where the farm is located the yield of the pasture is about 3000 kg DM per grazing season and hectar.This means that the pasture area should be 14,25 hectare to 57 milking cows.

Utvärdering av vibrationer inom vattenkrafts normer

The International Organization for Standardization (ISO) proposes vibration standards for the evaluation for machine damage due to vibration in rotational machines, where some vibration parameters are given to measure the vibrationgrade. This work evaluates the relevance of the vibration standards in hydro plants that are proposed by the ISO, and also investigates if there are methods used in other countries could have greater importance. Through statistical analysis of collected data we got a better understanding of relation among different vibration parameters, and also the importance of correct choice of the parameters for the evaluation of vibration. We have found that the vibration standards available today in hydro plants are not reliable for the judgment of vibration?s grade.

Kvalitetssäkring och processtyrningav ytstruktur på lackerat objekt

To be allowed to sell Z-suspended vehicles with dipped beam Xenon or LED lighting, Scania have to develop automatic headlight level control. This master?s thesis aims to be the foundation to that development.The thesis consists of several parts; a market analysis of how competitors to Scania and the general vehicle industry solve this problem; several available principles for detecting the amount of control needed; the construction of a test station for sensors, a control unit and components connected controlled by the control unit; a further theoretical and practical development of one principle ? one rotational sensor connected between the chassis and the back drive axis; a state flow model programmed in Simulink that produces the control signal for the headlight leveling from the sensor input.Lastly the thesis gives some recommendations to the further development and implementation of automatic headlight level control on Scania vehicles..

Crossbreeding in dairy cattle

The aim of this literature review is to give an overview of the differences between pure- and crossbreeding systems. Crossbreeding is a mating system with individuals of different lines or breeds. It is one of several breeding strategies in dairy production used to increase the economic profit. The use of crossbreeding increases due to changes in the dairy market and an increase of inbreeding among purebred Holstein. The main benefit of crossbreeding is heterosis, which is the improvement in genetic level in a hybrid offspring above the average of the parent breeds.

Automatisk nivåreglering av strålkastare

To be allowed to sell Z-suspended vehicles with dipped beam Xenon or LED lighting, Scania have to develop automatic headlight level control. This master?s thesis aims to be the foundation to that development.The thesis consists of several parts; a market analysis of how competitors to Scania and the general vehicle industry solve this problem; several available principles for detecting the amount of control needed; the construction of a test station for sensors, a control unit and components connected controlled by the control unit; a further theoretical and practical development of one principle ? one rotational sensor connected between the chassis and the back drive axis; a state flow model programmed in Simulink that produces the control signal for the headlight leveling from the sensor input.Lastly the thesis gives some recommendations to the further development and implementation of automatic headlight level control on Scania vehicles..

Design och konstruktion av Splitmaskin

During springterm 2010 Erik Persson and Magnus Hansson performed their ThesisWork with DIAB Laholm, in Hallands County for University of Halmstad.The project has been a product development project without exterior customers. Thusit had a great emphasis on functionality and less emphasis on marketing and such.This reflects the ambition to develop machinery to be used within the productionfacilities of DIAB Laholm, not to be sold to exterior customers.Main objective has been to create machinery which enables the production ofrotational symmetric work pieces within a NC-milling machine with 5 axles. Thework pieces milled will be made of DIAB?s material Divyncell with varyingdensities.The project has followed Fredy Olssons method involving Principal ? Primary ?Manufacturing constructions. However a complete manufacturing construction hasnot been made since DIAB just wanted a good Primary construction which will serveas a base for finishing touches at DIAB.By the end of the project material including calculations has been sent to DIAB andthey will finish the work and manufacture the machine if they find economic viabilityin this.The work method has been suited for this by several reasons, it was created withthese projects in mind and it?s also the method most familiar to us..

Konstruktion av 6:e axel på 5-axligportalfräsmaskin

During springterm 2010 Erik Persson and Magnus Hansson performed their ThesisWork with DIAB Laholm, in Hallands County for University of Halmstad.The project has been a product development project without exterior customers. Thusit had a great emphasis on functionality and less emphasis on marketing and such.This reflects the ambition to develop machinery to be used within the productionfacilities of DIAB Laholm, not to be sold to exterior customers.Main objective has been to create machinery which enables the production ofrotational symmetric work pieces within a NC-milling machine with 5 axles. Thework pieces milled will be made of DIAB?s material Divyncell with varyingdensities.The project has followed Fredy Olssons method involving Principal ? Primary ?Manufacturing constructions. However a complete manufacturing construction hasnot been made since DIAB just wanted a good Primary construction which will serveas a base for finishing touches at DIAB.By the end of the project material including calculations has been sent to DIAB andthey will finish the work and manufacture the machine if they find economic viabilityin this.The work method has been suited for this by several reasons, it was created withthese projects in mind and it?s also the method most familiar to us..

Framtagande av ny höjdmätningsmetod till försvarets antennhiss 861

This bachelor degree project was carried out at Saab AB Service and Repair, Arboga, Sweden. The objective was to design, construct and implement a new stable and reliable method of measuring the continuous vertical displacement (height) of the military search radar PS861 mounted on a hydraulic powered elevator. The end product needs to be durable enough to be fully operational in the harsh environment of an outdoor elevator shaft and yet as accurate and precise as possible since one of its purposes is to calibrate control equipment. Previously used technique has proven not to meet any of the above mentioned properties.A prototype using a high resolution quadrature output rotary encoder has been developed, allowing a completely digital interface. This new method has been evaluated in laboratory environment where tests have been conducted regarding both reliability and validity.

Energioptimering : Resteffektkylning av mellanlager för använt kärnbränsle (CLAB) Oskarshamn

This thesis is done in cooperation with SWECO Energuide in Växjö. They have been assigned by SKB in Oskarshamn to renew their electrical power supply and the ancillary processing systems in their Central provisional storage of spent nuclear fuel, CLAB. Today in the CLAB facility, the spent fuel is cooled down with water pumps, driven by asynchronous induction motors, where the water is regulated by mechanical valves to the desired flow. After the upgrade, the engines will be powered by AC drives that can control the pumps by changing the rotational speed and thus change the water's cooling effect on the nuclear fuel. In this study, I investigated the interference AC drives causes the feeding network and how to go about averting them.

Nyttjande av korsningar i mjölkproduktionen

Farmers? main reason for crossbreeding dairy cows is that they have seen a decline in functional traits, especially in the Holstein breed. Throughout crossbreeding, the farmers can combine functional and production traits of different dairy breeds and utilize the heterosis effects which emerge when two or more breeds are crossed. Results from different studies with Holstein crossed with Jersey, Brown Swiss, Normande and Scandinavian Red have shown that the crosses had higher fertility, longer productive life, had fewer stillborn calves and had easier calvings than purebred Holstein. The Holstein crosses have shown very good results and sometimes even better than the purebred Holstein for fat production, which gave higher amount of energy corrected milk (ECM) and higher income for the farmers.

Composition of fractions from air-classified wheat flour

The unique ability of wheat to produce leavened bread is mainly due to the gluten proteins present. As consumers are more and more attracted to bread with high fibre content the use of wheat gluten will also increase in order to obtain bread with good volume and appetizing characteristics. Air-classification is a technological method used to separate particles by size and shape by means of air-streams into two fractions, fine and coarse. When used on wheat flour it is known to alter the flour composition in the fractions obtained compared to the original flour. This method is not widely used in the milling industry but could possibly be of interest if protein rich fractions with favorable protein quality can be produced.

Utökning av mätområdet för turbinverkningsgraden på avgasturbo

The Goal with this Master of Science thesis is to expand the possible turbine efficiencymeasurements on an exhaust turbocharger. It was done as a part of the CICERO competencecentre. To feed the turbine with air a special flow rig has been used. Instead of loading theturbine by just restricting the compressor flow a docking system for an electrical dynamometer isdesigned to use the dynamometer as an additional loading source. By using an electricaldynamometer as loading device for the turbine, measurements are not depending on compressorperformance.A large part of the work consists in designing accessories for the dynamometer.

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