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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Natural head position: a photographic method and an evaluation of cranial reference planes in cephalometric analysis.

Madsen, David Peter. January 2007 (has links)
Commonly used craniofacial reference planes such as Frankfort Horizontal (FH) and sella nasion (SN) have shortcomings including their variable inter-individual orientation when related to true horizontal (HOR). Therefore, the aim of this study was to evaluate the potential usefulness of a range of craniofacial reference planes to HOR including those which have not been investigated before: Krogman-Walker line (KW line), neutral horizontal axis, foramen magnum line and posterior maxillary plane. A sample of 57 (38 female, 19 males) consecutive, pre-treatment orthodontic subjects aged 12 to 18 were photographically recorded in a standing mirror guided natural head position (NHP). Cephalograms taken at the same time were traced, oriented to a plumb line (true vertical) transferred from the photograph, and measured for statistical analysis. Thirty nine of these subjects were photographically recorded 2 months later to test the reproducibility of NHP. The results showed that the variability of the 11 selected craniofacial reference planes related to HOR was generally high. The planes illustrating lowest variability to HOR were FH and KW line with standard deviations of 4.6° and 4.7°, respectively. These, however, showed about double the variation in NHP reproducibility (Dahlberg 2.1°). The KW line and palatal plane were also oriented closest to HOR on average. Therefore, KW line and palatal plane are potential substitutes for the commonly used reference planes in the absence of a reliable NHP. However, NHP still represents a more valid craniofacial reference system than the investigated reference planes. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297323 / Thesis (D.Clin.Dent.) - School of Dentistry, (Orthodonitics), 2007
172

Socioekonomisk position och hälsa : ett välfärdsperspektiv på hälsoskillnader bland de äldsta i Sverige

Ringmar, Edith January 2009 (has links)
No description available.
173

Ledarskap, syskonposition och locus of control

Hasselblad, Emelie January 2008 (has links)
<p>En majoritet bland ledare i olika organisationer har en bakgrund som storasyskon eller ensambarn (Hudson, 1990). Denna studie genomfördes för att få svar på om personer med ledaransvar skiljer sig åt gällande syskonplats och locus of control jämfört med de personer som inte har ledaransvar. Ledare och medarbetare på en statlig myndighet svarade på en enkät gällande plats i syskonskara, erfarenhet av ledarskap och locus of control. Resultatet visade att sistfödda i detta urval hade en högre grad av intern locus of control än förstfödda vilket kan tyda på en annan typ av sistfödd på denna myndighet. Urvalet var dock bristfälligt (N = 48) och slutsats kunde inte dras utan att riskera ett felaktigt resultat.</p>
174

Socioeconomic inequalities in fruit and vegetable consumption in Stockholm County : a comparative descriptive analysis / Socioekonomiska ojämlikheter i frukt- och grönsakskonsumtion : en jämförande deskriptiv analys

Goncalves, Lina January 2010 (has links)
<p>This thesis described socioeconomic inequalities in fruit and vegetable consumption in Stockholm County.<strong> </strong>A comparative descriptive analysis was carried out with the use of secondary data from the 2006 Stockholm County Public Health Survey. The data was analyzed through cross tabulations that were conducted in SPSS.<strong> </strong>The findings showed that people with high socioeconomic position consumed fruit and vegetables more frequently than those of low socioeconomic position. Differences in fruit and vegetable consumption were found for the three measures of socioeconomic position; education, occupation and income. These differences were pronounced to a larger extent across different education levels compared to levels of occupation and income. Further research is needed to investigate which factors may explain the observed differences.</p>
175

Does photographic documentation of the position of the recording electrodes decrease motor amplitude variation in electroneurography?

Abdulrahman, Hazha, Mach, Aaron January 2009 (has links)
<p>It is known that there is an intraindividual amplitude variation in motor electroneurography when the same person is examined at different times. This variation affects the evaluation the status of the patient. The aim of this study was to investigate if the intraindividual amplitude variation decreased by photographing the electrode position, that later is used in the follow-up study. Twenty test persons were examined by four laboratory scientists. The nerves that were examined were median, ulnar, peroneal and tibial nerve. At the first examination the laboratory scientists used method guidelines and took photographs of the electrode position. The photographs were then used in the follow-up. The results showed that there was an indication of decreased of the intraindividual amplitude variation when photographic documentation was used instead of method guidelines.</p>
176

Vision based navigation system for autonomous proximity operations: an experimental and analytical study

Du, Ju-Young 17 February 2005 (has links)
This dissertation presents an experimental and analytical study of the Vision Based Navigation system (VisNav). VisNav is a novel intelligent optical sensor system invented by Texas A&M University recently for autonomous proximity operations. This dissertation is focused on system calibration techniques and navigation algorithms. This dissertation is composed of four parts. First, the fundamental hardware and software design configuration of the VisNav system is introduced. Second, system calibration techniques are discussed that should enable an accurate VisNav system application, as well as characterization of errors. Third, a new six degree-of-freedom navigation algorithm based on the Gaussian Least Squares Differential Correction is presented that provides a geometrical best position and attitude estimates through batch iterations. Finally, a dynamic state estimation algorithm utilizing the Extended Kalman Filter (EKF) is developed that recursively estimates position, attitude, linear velocities, and angular rates. Moreover, an approach for integration of VisNav measurements with those made by an Inertial Measuring Unit (IMU) is derived. This novel VisNav/IMU integration technique is shown to significantly improve the navigation accuracy and guarantee the robustness of the navigation system in the event of occasional dropout of VisNav data.
177

Position Sensitive Detectors : Device Technology and Applications in Spectroscopy

Andersson, Henrik January 2008 (has links)
This thesis deals with the development, processing and characterization of position sensitive detectors and, in addition, to the development of compact and cost effective spectrometers. Position sensitive detectors are used to measure, with great accuracy and speed, the position of a light spot incident on the surface. Their main use is for triangulation, displacement and vibration measurements. A type of position sensitive detector based on the MOS principle and using optically transparent indium tin oxide as a gate contact has been developed. This type of detector utilizes the MOS principle where an induced channel forms beneath the gate oxide in the surface of the Silicon substrate. One and two dimensional detectors have both been fabricated and characterized. The first measurements showed that the linearity did not fulfil expectations and it was suspected that stress induced by the gate contact could be the reason for the seemingly high nonlinearity. Further investigations into both the p-n junction and the MOS type position sensitive detectors lead to the conclusion that the indium tin oxide gate is responsible for inducing a substantial stress in the surface of the detector, thus giving rise to increased position nonlinearity. The heat treatment step which was conducted was determined to be critical as either a too short or too long heat treatment resulted in stress in the gate and channel leading to position nonlinearity. If a correctly timed heat treatment is performed then the detector’s linearity is in parity with the best commercial position sensitive detectors. In addition, the development of very small, compact and cost effective spectrometers has been performed with the aim of constructing devices for use in the process industry. The development of a wedge shaped array of Fabry-Perot interferometers that can be mounted directly on top of a detector makes it possible to construct a very compact spectrometer using the minimum amount of optics. This wedge interferometer has been evaluated by means of array pixel detectors and position sensitive detectors for both the infrared and the visible wavelength ranges. When used with a position sensitive detector it is necessary to use a slit to record the intensity of the interferogram for many points over the detector, equivalent to pixels on an array detector. Usually the use of moving parts in a spectrometer will impose the use of high precision scanning mechanisms and calibration. By using a position sensitive detector for the interferogram readout both the position and the intensity are known for every measurement point and thus the demands placed on the scanning system are minimized. / Denna avhandling behandlar utveckling, processning och karakterisering av positionskänsliga detektorer och även utveckling av kompakta, kostnadseffektiva spektrometrar. Positionskänsliga detektorer används för att mäta positionen av en infallande ljuspunkt på ytan med hög noggrannhet och hastighet. Det huvudsakliga användningsområdet är triangulering, förskjutnings och vibrationsmätningar. En typ av positionskänslig detektor baserad på MOS principen och som använder optiskt transparent indium-tenn-oxid som ”gate” kontakt har utvecklats och karakteriserats. Denna typ av detektor utnyttjar MOS principen där en inducerad kanal bildas under ”gate” oxiden i ytan på kiselsubstratet. Både en endimensionell och en tvådimensionell detektor har tillverkats och karakteriserats. De första mätningarna visade på att linjäriteten inte var den förväntade och det misstänktes att stress inducerad av ”gate” kontakten kunde vara orsaken till den tillsynes för höga ickelinjäriteten. Ytterligare undersökning på både p-n och MOS positionskänsliga detektorer ledde till slutsatsen att indium-tenn-oxid ”gate” kontakten är ansvarig för att orsaka en väsentlig stress i ytan på detektorn och därigenom orsaka ökad olinjäritet i positionsbestämningen. Värmebehandlingssteget som utförs fastställdes vara kritiskt där en för kort eller för lång värmebehandling resulterar i stress i ”gate” kontakten och kanalen som leder till olinjäritet. Om en korrekt värmebehandling utförs så är de tillverkade detektorernas linjäritet i paritet med de bästa kommersiella positionskänsliga detektorerna. Utveckling av väldigt små, kompakta och kostnadseffektiva spektrometrar har också utförts med målet att konstruera enheter för användning i process industrin. Utvecklingen av en kilformad ”array” av Fabry-Perot interferometrar som kan monteras direkt på en detektor gör det möjligt att konstruera en väldigt kompakt spektrometer med minimalt med optik. Denna kilformade interferometer har utvärderats med arraydetektorer, både för det infraröda och det synliga våglängdsområdet, och också med positionskänsliga detektorer. När den används med en positionskänslig detektor så är det nödvändigt att använda en springa att begränsa ljuset med för att registrera intensiteten av interferrogrammet i många punkter över detektorn, vilket är likvärdigt med pixlar på en arraydetektor. Vanligtvis gör användandet av rörliga delar i en spektrometer att mekanismer med hög precision och kalibrering måste användas. Genom att använda en positionskänslig detektor för att läsa ut interferrogrammet så kommer både positionen såväl som ljusintensiteten att vara känd i varje mätpunkt och därför minimeras kravet på förflyttningsmekanismen.
178

Socioeconomic inequalities in fruit and vegetable consumption in Stockholm County : a comparative descriptive analysis / Socioekonomiska ojämlikheter i frukt- och grönsakskonsumtion : en jämförande deskriptiv analys

Goncalves, Lina January 2010 (has links)
This thesis described socioeconomic inequalities in fruit and vegetable consumption in Stockholm County. A comparative descriptive analysis was carried out with the use of secondary data from the 2006 Stockholm County Public Health Survey. The data was analyzed through cross tabulations that were conducted in SPSS. The findings showed that people with high socioeconomic position consumed fruit and vegetables more frequently than those of low socioeconomic position. Differences in fruit and vegetable consumption were found for the three measures of socioeconomic position; education, occupation and income. These differences were pronounced to a larger extent across different education levels compared to levels of occupation and income. Further research is needed to investigate which factors may explain the observed differences.
179

Does photographic documentation of the position of the recording electrodes decrease motor amplitude variation in electroneurography?

Abdulrahman, Hazha, Mach, Aaron January 2009 (has links)
It is known that there is an intraindividual amplitude variation in motor electroneurography when the same person is examined at different times. This variation affects the evaluation the status of the patient. The aim of this study was to investigate if the intraindividual amplitude variation decreased by photographing the electrode position, that later is used in the follow-up study. Twenty test persons were examined by four laboratory scientists. The nerves that were examined were median, ulnar, peroneal and tibial nerve. At the first examination the laboratory scientists used method guidelines and took photographs of the electrode position. The photographs were then used in the follow-up. The results showed that there was an indication of decreased of the intraindividual amplitude variation when photographic documentation was used instead of method guidelines.
180

Ledarskap, syskonposition och locus of control

Hasselblad, Emelie January 2008 (has links)
En majoritet bland ledare i olika organisationer har en bakgrund som storasyskon eller ensambarn (Hudson, 1990). Denna studie genomfördes för att få svar på om personer med ledaransvar skiljer sig åt gällande syskonplats och locus of control jämfört med de personer som inte har ledaransvar. Ledare och medarbetare på en statlig myndighet svarade på en enkät gällande plats i syskonskara, erfarenhet av ledarskap och locus of control. Resultatet visade att sistfödda i detta urval hade en högre grad av intern locus of control än förstfödda vilket kan tyda på en annan typ av sistfödd på denna myndighet. Urvalet var dock bristfälligt (N = 48) och slutsats kunde inte dras utan att riskera ett felaktigt resultat.

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