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620 Uppsatser om Constant Fraction Detection - Sida 1 av 42
Implementering av Constant Fraction Detection vid avståndsmätning
This thesis is performed at Saab Bofors Dynamics in Karlskoga and investigates a technique for ranging with laser pulses. The investigated technique is called Constant Fraction Detection (CFD). Described briefly, the received laser pulse is split into two equal parts, where one part is delayed half the pulse width and inverted. This signal is added to the original pulse. The resulting curve has the shape of a laying S and the detection of the zero level is used to stop the time measurement.
Use of dogs as odour detectors : a review of the scientific literture
A lot of various substances can be detected by dogs, as oestrous in cows, endangered species or non-biological substances like accelerants, narcotics, explosives, mines and pollutions and biological substances like identity (suspects), cancer (breast, lung, colorectal and bladder cancer), human remains (cadaver), bacteria and mould in buildings. The dogs are trained using non-scientific methods and not much research in detection training exists. This is a review of different types of dog detection, with focus on new research..
Detektering av sprickor i vägytor med hjälp av Datorseende
This thesis describes new methods for automatic crack detection in pavements. Cracks in pavements can be used as an early indication for the need of reparation.Automatic crack detection is preferable compared to manual inventory; the repeatability can be better, the inventory can be done at a higher speed and can be done without interruption of the traffic.The automatic and semi-automatic crack detection systems that exist today use Image Analysis methods. There are today powerful methods available in the area of Computer Vision. These methods work in higher dimensions with greater complexity and generate measures of local signal properties, while Image Analyses methods for crack detection use morphological operations on binary images.Methods for digitalizing video data on VHS-cassettes and stitching images from nearby frames have been developed.Four methods for crack detection have been evaluated, and two of them have been used to form a crack detection and classification program implemented in the calculation program Matlab.One image set was used during the implementation and another image set was used for validation. The crack detection system did perform correct detection on 99.2 percent when analysing the images which were used during implementation.
Objektdetektering i SAR- och IR-bilder
This report treats detection in IR-pictures taken from airplanes over the ground. The detection is divided in two parts. First there is a detection with filterkernels with the task to point on targets and objects that look like targets. The second part is a discriminator that demands more calculations and has the task to sort out the false alarms from the discriminator. Both the detector and the discriminator contain thresholds thats been trained from trainingsets of data.
Inverkan av flisig krossballast på betong
Concrete is one of the world?s most common construction materials and is composed of 70-80 % stone material. Today crushed stone is used as aggregate in concrete in order to replace natural aggregates due to strong environmental reasons. Stone crushing yields flaky material and in this thesis studies are made on the flaky particle shape and how it influence properties of concrete such as workability, rheology and strength. The concrete recipes used in this thesis have fixed values, the only variable is the flakiness of the crushed stone.
Siktning som saneringsmetod för metallförorenad mark
Toxic metals contaminate soil worldwide and thus serve as sever environmental threat. Therefore the purposes of this study were to investigate in which soil fractions that different heavy metals (Fe, As, Cu, Zn and Pb) could be found in contaminated soils and if it is possible to use sieving as a method for decontamination. Soil samples were collected from three different locations, the Nasa silver mine, the Blaiken-mine and Svalget environmental station. The samples were oven dried and later on sieved into six different fractions 8mm, 4 mm, 0.5 mm, 0.250mm, 0.063 mm and <0.063 mm. The fractions 4 mm, 0.5 mm and <0.063 mm from each location were analyzed in an x-ray fluorescence detector.
Heuristisk detektering av trojaner
The heuristic methods used by the anti-trojan application TrojanHunter have been evaluated. The evaluation shows that the heuristic scan engine of TrojanHunter has a very good detection ratio and that the detection ratio can be even further improved by implementing the suggested improvements, the most important of which is a white list to avoid misidentifying files that are known not to be trojans..
Mapping of clear-cuts in Swedish forest using satellite images acquired by the radar sensor ALOS PALSAR
This study presents results for observing forest changes in Sweden using multi-temporal L-band satellite data and is a part of the JAXA?s ALOS Kyoto and Carbon Initiative. An extensive dataset of images acquired by the Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) is investigated for clear-cut detection in boreal forests in northern Sweden (Lat. 64°14? N, Long.
Ett flervariabelt feldetekteringssystem för övervakning av bärlagertemperaturen i vattenkraftturbiner
The purpose of this thesis work was to develop an automatic fault detection system for surveillance of bearing temperature in hydropower turbines. The parameters used except the bearing temperature were cooling water temperature and cooling water flow. A simple static model based on data sampled every minute was developed to estimate the bearing temperature. Then a detector for detection of change in bearing temperature based on the CUSUM-algorithm was designed. Since the amount of data was very small the developed model was too uncertain to be used in a working system.The designed fault detection system showed to work well for the available data.
Registrering och avel för brunstvisningsförmåga hos mjölkkor
Dairy farmers using artificial insemination (AI) are dependent on effective oestrus detection. In Sweden, AI is used for a majority of all dairy cows and oestrus synchronisation with hormones is not allowed. There are reports of declining ability to express oestrus with higher levels of milk production. This makes oestrus detection more difficult. Several aids for oestrus detection have been developed, for instance pedometers and mounting detectors.
Blinkbeteendebaserad trötthetsdetektering : metodutveckling och validering
Electrooculogram (EOG) data was used to develop, adjust and validate a method for drowsiness detection in drivers. The drowsiness detection was based on changes in blink behaviour and classification was made on a four graded scale. The purpose was to detect early signs of drowsiness in order to warn a driver. MATLAB was used for implementation. For adjustment and validatation, two different reference measures were used; driver reported ratings of drowsiness and an electroencephalogram (EEG) based scoring scale.
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.
Uppfångning och kvarhållning av 134Cs och 85Sr i olika växtutvecklingsstadier
Emissions of radionuclides to the atmosphere can lead to wet deposition on plants in the event of rainfall. An increased level of radioactivity in the plants may occur due to interception and retention of the radionuclides. If the content of the plants is above the threshold limit value, entire yields may have to be destroyed. In order to prevent contamination or decrease the content countermeasures can be taken. The impact of the
biomass, leaf area index (LAI) and growth stage of the plant on the interception and retention is important to know in order to decide which countermeasures to use.
Weather may also be an important factor.
In this work the interception and retention of 134Cs and 85Sr by spring wheat, ley and spring oil-seed rape was studied.
Passive acoustic diver detection
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.
Konfigurering av slutartider för ljusdetekterande mjukvara
This project measures the upper bound of exposure time for laser reflection detection in the software DotDetector. Via measurement of the exposure time for which distortion happens in a room lit with everyday light we conclude that the upper bound for exposure times are 100 milliseconds. This value does not change as long as the lighting in the room is the same. As future work this project proposes variable upper bounds depending on secondary lighting in the room. Also we propose automating the colour masking of the detection algorithm..