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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.
11

High Frequency Raster Magnets Design for the ARIEL Electron Target Station at TRIUMF

Ishida, Mathew 22 August 2022 (has links)
TRIUMF, Canada’s nuclear and particle physics research laboratory is currently in development of an Advanced Rare Isotope Facility (ARIEL) that will contain a newly designed electron target station. The target at this station is susceptible to destruction from instantaneous spot heating of the beam. To mitigate this, a raster system consisting of two AC electromagnets was proposed. The two magnets will work in tandem, vertical and horizontal, bending to produce raster patterns at 10 kHz. Since complex patterns consist of harmonics higher than the fundamental frequency, a design frequency of 100 kHz was chosen. AC current causes eddy currents which lead to the skin effect, causing high frequency current to concentrate on the outside of the conductor. To address this, a conductor diameter smaller than the skin depth at the given frequency must be chosen. This led to the choice of litz wire consisting of 400 insulated strands for the conductor. The radiation resistance insulation ethylene tetrafluoroethylene (ETFE) was chosen for these conductors and a 3D printed polyethylene sulfide (PPS) will be used for the coil bobbins. The effects of eddy currents were eliminated from the core material by choosing ferrite, an amorphous material consisting of iron-oxide crystals. Simulations were completed to ensure a homogenous magnetic field in the region of the beam, and the subsequent pole profile was determined. Lastly, a metalized ceramic beampipe is used to integrate with the existing beamline and allow for discharge of any static buildup on the inner surface of the beampipe due to the electron beam. / Graduate
12

A Raster-Scan Video Graphics Display System Implemented on a KIM Microcomputer

Drummond, Mark Douglas 09 1900 (has links)
<p> The "microelectronic revolution" and the accompanying decrease in the cost of semiconductor memory has increased the availability of raster-scan graphical displays, yet, as pointed out in a recent survey [BAE79], the implementation of graphics software for raster-scan systems has lagged behind that for random-scan systems. The aim of the work described in this report has been to apply random-scan display techniques to a system employing a relatively inexpensive raster-scan device. The system, incorporating a segmented display file processor, is implemented on a KIM^TM microcomputer. The display device is composed of a Micro Technology Unlimited^TM (MTU) 8K Visable Memory^TM (VM) video board and a standard TV monitor.</p> / Thesis / Master of Science (MSc)
13

Visuell utvärdering av frekvensmodulerat raster på obestruket papper.

Blomqvist, Emilie, Cedergren, Veronica January 2010 (has links)
This thesis investigated if a combination of increased under colour removal (decreasing the total ink limit), normal andincreased density and modern FM-screening could be used to provide a visually better print on uncoated and coated paperin comparison with AM-screening using the same conditions.Two different test groups (one with graphic background, the other with no graphic background) were asked to a visuallyassess the quality of the prints presented in a pair comparison using a reference image.The results show that the FM-screening did not obtain any significant visual difference in comparison with AM-screening,regardless of paper types and density levels. In general however, prints on coated paper were graded higher.
14

Υπολογιστικό εργαλείο για την απεικόνιση της χρονικής συσχέτισης των εγκεφαλικών ρυθμών του ύπνου

Πάτση, Γεωργία 02 February 2012 (has links)
Το φαινόμενο του ύπνου αποτελεί ένα μυστήριο της ανθρώπινης ζωής. Η έρευνα του φαινομένου του ύπνου γίνεται κυρίως μέσω καταγραφών Ηλεκτροεγκεφαλογραφήματος. Η επεξεργασία και η ανάλυση του ηλεκτροεγκεφαλογραφήματος ύπνου με την χρήση υπολογιστικών αλγορίθμων έχει δώσει μεγάλη ώθηση στην διερεύνηση της εγκεφαλικής δραστηριότητας. Κατά την διάρκεια του ύπνου παρουσιάζονται χαρακτηριστικοί ρυθμοί και κύματα όπως είναι οι άτρακτοι (spindles) και τα συμπλέγματα Κ (K-Complex). Η ακριβής σημασία και συμβολή των συγκεκριμένων ρυθμών δεν έχει πλήρως διερευνηθεί. Πιστεύεται όμως ότι έχουν σπουδαίο υπναγωγικό ρόλο και συμβάλλουν στις διαδικασίες σταθεροποίησης της μνήμης κατά τον ύπνο. Στην παρούσα εργασία γίνεται μια προσπάθεια εύρεσης της χρονικής συσχέτισης μεταξύ των εμφανιζόμενων ρυθμών και κυμάτων κατά την διάρκεια του ύπνου. Για την ανάπτυξη του προγράμματος χρησιμοποιήθηκε το εργαλείο που έχει αναπτυχθεί και χρησιμοποιείται για επεξεργασία σήματος στο Εργαστήριο Νευροφυσιολογίας του Πανεπιστημίου Πατρών (Flying Circus). Το συγκεκριμένο πρόγραμμα επεκτάθηκε με τις κατάλληλες ρουτίνες έτσι ώστε να παράγονται γραφικές απεικονίσεις των χρονικών στιγμών εμφάνισης των ΗΕΓ χαρακτηριστικών εκ των οποίων να συνάγεται οπτικά αν υπάρχει συσχέτιση μεταξύ τους, το ψηφιδόπλεγμα (raster). Ο χρήστης μπορεί να επιλέξει είτε την συσχέτιση των ρυθμών στον χρόνο (time raster) είτε την συσχέτιση των ρυθμών στο πεδίο των συχνοτήτων (spectrum raster). Στην εργασία παρουσιάζονται οι γραφικές απεικονίσεις και τα αποτελέσματα από την χρήση του προγράμματος σε καταγραφές ύπνου που έχουν γίνει στο Εργαστήριο Νευροφυσιολογίας. / Sleep is a mysterious phenomenon of human life. Electroencephalogram (EEG) is the main tool that researchers use to explore the physiology of sleep. Advanced analysis of sleep recordings enormously contributed to the research and understanding of brain activity. During sleep we observe some characteristic rhythms and waves such as spindles and K-Complexes. The exact meaning and role of these rhythms has not yet fully discovered. However, it is believed that they play a significant sleep promoting role and partake in cognitive processes of sleep. The present work attempts to find the temporal correlation between those rhythms and waves that appear during the second stage of non-REM sleep i.e. whether any changes in the rate of occurrence of spindles can predict or can be predicted by the occurrence of K-Complexes. A graphic interface tool was developed by adding new processing functions to the tool that is used at the Neurophysiology Unit of the University of Patras’ Medical School (Flying Circus). This program is a raster used to support the EEG studies with the appropriate routines in order to produce graphical representations of the time development of various EEG characteristics and to demonstrate visually any possible correlation between them. The new environment includes methods that can correlate the appearance of rhythms and waves in the time domain or in the frequency spectrum domain using the raster graphical representation. The result of these methods is either a time raster or a spectrum raster depending on the user choices. In this paper we present the results of using these methods in real sleep recordings that have been conducted in the Neurophysiology Unit.
15

Using Suitability and Proximity Analysis to Discover Houston's Accessibility via Roadways and Public Transportation

Lagarde, Ethan January 2015 (has links)
Houston is one of the fastest growing metropolis’ in the country. Driving this growth is the oil and gas industry and also the Texas Medical Center, the world’s largest medical center. With such growth comes various problems. One of the leading problems according to its citizens in 2014 was traffic and the lack of access to public transportation. This project aims to help find solutions to this problem by locating areas that could help improve public transportation access and take a look at Houston’s accessibility via roadways. Using datasets from various Houston agencies such as the City of Houston and the Houston-Galveston Area Council, overlay analysis was used to help find prime areas that could be improved. Using ESRI ArcMap, models were completed in order to automate the analysis process. Tools such as raster conversion, Euclidean distance, zonal stats as table, and reclassify were used. In order to analyze Houston accessibility via the roadways, ArcGIS Online was used. Several Proximity analyses were run in order to view various types of dating dealing with the accessibility of Houston using roadways. The results show areas that do not currently have access to public transportation and areas that would be suitable locations for improvements based on different criteria. For roadway access, the results show average commute times, drive-time accessibility, and freeway access. This will allow for the accessibility of Houston to be shown whether it is by public transportation or by roadway.
16

Hur upplever elever raster? : En fenomenologisk studie

Åberg, Anna January 2007 (has links)
<p>The essential thing about breaks has been in relation to time, body, movement, force and room during my examination. Through conversations high-school students from two schools have taken part in this study. The examination is based on conversations with the students and has focused on students’ experiences of breaks, and is also carried through by the method of phenomenology. The results of my studie show that students - during their breaks - experience a feeling of allways heading for something and also that time seem to exist in three levels: filled time, non-filled time and flow regarding of time. Since time has such important influence in my examination, there is also results that show that a break of 20 minutes is the optimal break; the essence of the phenomen.</p>
17

Planerade rastaktivitet : En kvalitativ studie om fritidslärares upplevelser av rastaktiviteters betydelse för elevers sociala samspel

Björklund, Pontus, Björklund, Oskar January 2019 (has links)
Syftet med vår studie är att öka kunskapen om fritidslärares upplevelser av rastaktiviteters betydelse för elevers sociala samspel. Undersökningen grundas på kvalitativa intervjuer med åtta fritidslärare som jobbar på tre olika skolor och våra forskningsfrågor är: Vilken erfarenhet har fritidslärare av raster och rastaktiviteter? Vilken betydelse får rastaktiviteterna för kamratrelationer då den genomförs av en lärare? Vilken betydelse har rastaktiviteter för elevers grupperingar? På vilket sätt har rastaktiviteter betydelse för elevers sociala samspel? Resultatet av studien visar att alla fritidslärare anser att rastaktiviteter kan skapa möjligheter för kamratrelationer och lärande. Av resultaten framgår att rastaktiviteter ökar elevernas sociala samspel och att ansvaret att hitta en kompis inte ligger på eleven. Studien pekar också på att fritidslärare menar att grupperingar bland elever inte bryts automatiskt med rastaktiviteter. Däremot om intentionen är att bryta grupperingar på skolan kan detta vara möjligt med hjälp av rastaktiviteter. Vidare visar resultatet att det krävs personal, tid och samarbete inom hela skolan för att rastaktiviteter ska fungera.
18

Rastens renässans : En studie om hur personalen på en skola beskriver sin psykosociala arbetsmiljö med fokus på raster och pauser / Renaissance of the Break

Boström, Karin January 2004 (has links)
<p>Syftet med det här arbetet har varit att undersöka den psykosociala arbetsmiljön på en skola med fokus på personalens raster och pauser. Jag har, dels genom egna erfarenheter under lärarutbildningen och dels genom att ta del av Nordängers avhandling Lärares raster, Innehåll i mellanrum (2002), tagit del av information som visar på att det är bristfälligt med raster och pauser på en del skolor. Informationen pekar på olika aspekter som hindrar personalen att kunna ta ut sina raster. Några av dessa aspekter är att personalen blir hindrad av eleverna, de måste förbereda lektionerna och de måste få tag på någon under sin rast. Med mitt arbete ville jag peka på en möjlighet till förändring i positiv riktning. Jag anser att det är mycket viktigt för människans hälsa att ha raster och pauser för att få tid att återhämta sig och för att orka med sitt arbete. Jag genomförde fyra kvalitativa intervjuer på en skola som verkade ha väl fungerande raster och pauser. Resultatet av min undersökning visar på att denna skola har väl fungerande raster och pauser och en stor bidragande orsak till att det fungerar verkar vara ett aktivt fackligt arbete på skolan. Man har lyckats väl med att informera personalen om vilka rättigheter den har. Personalen har också fått stor frihet från ledningen att själva lägga sina scheman. Resultatet pekar också på ett gott socialt klimat, en öppen, rak kommunikation och hög grad av trivsel. Dock upplever man också brister på skolan när det gäller lokaler och städning. I viss mån upplever personalen även brist på pedagogiska diskussioner, feedback och tid. Genom detta arbete kan jag dra slutsatsen att det faktiskt går att ordna det så att skolpersonal kan ha fungerande raster och pauser.</p>
19

Batch-digitalisering och GIS-anpassning av analoga enkätdata / Batch-digitalizing and GIS adaptation of analogue visitor survey data

Ala-Häivälä, Anders January 2007 (has links)
<p>I denna rapport beskrivs arbetet med att tillvarata och anpassa data från en enkätundersökning till digital hantering i GIS. Undersökningen är en besöksstudie utförd av Karlstads kommun och Skogsstyrelsen för att kartlägga människors rörelsemönster i I2-Skogen, ett gammalt militärt övningsfält som numera används som rekreationsområde. Enkäten består av ett antal frågor om exempelvis typ av aktivitet, ålder och åsikter om området, samt en karta på vilken besökaren ritat in var i området han eller hon rört sig. Utgångsmaterialet för arbetet har varit en databas innehållande enkätsvaren, samt originalkartorna med den ritade informationen. Arbetet omfattar dels att undersöka om kartinformationen kan digitaliseras automatiskt genom scanning och vektorisering i batch, och dels att normalisera och strukturera databasen med enkätsvaren.</p><p>En metod för digitalisering har utarbetats och testats på ett urval av kartorna. Metoden består av ett antal steg och innefattar bl a bearbetning av kartorna i bildbehandlingsprogram samt klassning och vektorisering i GIS-programvara. Eftersom batchfunktioner saknas i GIS-programvaran har makron skapats genom programmering i VBA. Metoden har visat sig fungera bra på urvalet och slutsatsen blir att det är fullt möjligt att digitalisera de ritade linjerna med automatik. Dock finns vissa brister avseende noggrannhet och användbarhet. Dessutom är urvalet relativt litet och viss justering av inställningarna för klassning och vektorisering kan vara nödvändig vid tillämpning på större delar av materialet.</p><p>Databasen har normaliserats så långt som ansetts rimligt med tanke på prestanda och användbarhet. För att tillförlitliga sökningar ska kunna utföras har flera attribut tolkats och modifierats genom indelning i kategorier och intervall.</p><p>Arbetet har resulterat i en geodatabas innehållande samtliga enkätsvar samt det utvalda materialet från digitaliseringstestet. För att visa hur databasen kan användas har två enkla analysexempel tagits fram.</p> / <p>This report describes the work with utilizing and adapting data from a visitor poll for use in a GIS. The poll was performed by the Municipality of Karlstad and the Swedish Forest Agency to survey peoples visit patterns in the I2-Forest, a former military training field which is now used as a recreation area. The poll consists of a number of questions about the visitor’s activities, age, opinions etc, and a map on which the visitor has drawn his or her path through the forest. Source data is a database containing poll answers, and the original maps with the drawn information. The task is partly to investigate if the maps can be batch-digitalized through scanning and vectorization, and partly to normalize the database.</p><p>A method for digitalizing has been developed and tested on a selection of the maps. The method consists of a number of steps, including image processing, classification and vectorization. According to lack of batch-possibilities in the used GIS software, macros have been created by programming in VBA. The method works well on the selected maps and the conclusion is that it is possible to digitalize the drawn lines automatically. However, there are some shortages regarding accuracy and usability. Furthermore, the selection is relatively small and some adjustments on the settings for classification and vectorization might be necessary when applying the method on a larger part of the data.</p><p>The database has been normalized as far as reasonable with consideration of performance and usability. To enable reliable searches, several attributes has been interpreted and modified through categorization and classification.</p><p>The result is a geodatabase consisting of all poll answers, and the selected data from the digitalization test. To show how the database can be used, two simple examples of analyses have been made.</p>
20

Hur upplever elever raster? : En fenomenologisk studie

Åberg, Anna January 2007 (has links)
The essential thing about breaks has been in relation to time, body, movement, force and room during my examination. Through conversations high-school students from two schools have taken part in this study. The examination is based on conversations with the students and has focused on students’ experiences of breaks, and is also carried through by the method of phenomenology. The results of my studie show that students - during their breaks - experience a feeling of allways heading for something and also that time seem to exist in three levels: filled time, non-filled time and flow regarding of time. Since time has such important influence in my examination, there is also results that show that a break of 20 minutes is the optimal break; the essence of the phenomen.

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