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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.
271

A POLARIZATION-AGILE RADIATION TECHNIQUE FOR TESTING TELEMETRY RECEIVING SITES AT WHITE SANDS MISSILE RANGE

Vines, Roger, Shaw, Stephen 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Telemetry receiving sites at missile test ranges almost always use polarization diversity to maximize the quality of the telemetry signals collected from missiles during developmental tests. If the sites are operating optimally, their sensitivity should be independent of received polarization. In this paper a technique to test the sensitivity of each receiving site is presented that involves radiating from a central location with selectable polarization and precise power level. Results of testing five telemetry sites are presented and compared with performance predicted through link analysis using site G/T and location information.
272

ENCRYPTED BIT ERROR RATE TESTING

Guadiana, Juan M., Macias, Fil 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / End-to-End testing is a tool for verifying that Range Telemetry (TM) System Equipment will deliver satisfactory performance throughout a planned flight test. A thorough test verifies system thresholds while gauging projected mission loading all in the presence of expected interference. At the White Sands Missile Range (WSMR) in New Mexico, system tests are routinely conducted by Range telemetry Engineers and technicians in the interest of ensuring highly reliable telemetry acquisition. Even so, flight or integration tests are occasionally halted, unable to complete these telemetry checks. The Navy Standard Missile Program Office and the White Sands Missile Range, have proactively conducted investigations to identify and eliminate problems. A background discussion is provided on the serious problems with the launcher acquisition, which were resolved along the way laying the ground work for effective system testing. Since there were no provisions to test with the decryption equipment an assumption must be made. Encryption is operationally transparent and reliable. Encryption has wide application, and for that reason the above assumption must be made with confidence. A comprehensive mission day encrypted systems test is proposed. Those involved with encrypted telemetry systems, and those experiencing seemingly unexplainable data degradations and other problems with or without encryption should review this information.
273

A DESKTOP SATELLITE DATA PROCESSING SYSTEM

Brown, Barbie, Ghuman, Parminder, Medina, Johnny, Wilke, Randy 10 1900 (has links)
International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The international space community, including National Aeronautics and Space Administration (NASA), European Space Agency (ESA), Japanese National Space Agency (NASDA) and others, are committed to using the Consultative Committee for Space Data Systems (CCSDS) recommendations for low earth orbiting satellites. With the advent of the CCSDS standards and the availability of direct broadcast data from a number of current and future spacecraft, a large number of users could have access to earth science data. However, to allow for the largest possible user base, the cost of processing this data must be as low as possible. By utilizing Very Large Scale Integration (VLSI) Application-Specific Integrated Circuits (ASIC), pipelined data processing, and advanced software development technology and tools, highly integrated CCSDS data processing can be attained in a single desktop system. This paper describes a prototype desktop system based on the Peripheral Component Interconnect (PCI) bus that performs CCSDS standard frame synchronization, bit transition density decoding, Cyclical Redundancy Check (CRC) error checking, Reed-Solomon decoding, data unit sorting, packet extraction, annotation and other CCSDS service processing. Also discussed is software technology used to increase the flexibility and usability of the desktop system. The reproduction cost for the system described is less than 1/8th the current cost of commercially available CCSDS data processing systems.
274

An investment strategy based on return on capital and earnings yield

Howard, William Ford 04 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Portfolio managers and investors have developed numerous stock-picking strategies for managing stock market portfolios, many of which have been researched extensively in international markets. For example, research has shown that value stocks have higher returns than growth stocks in markets around the world (Fama & French 1998). A very popular value investing strategy is the ‘magic formula’ developed and published by Joel Greenblatt, in 2006, in his book The little book that beats the market. This strategy is based on constructing portfolios where return on capital and earnings yield are used as selection criteria. Greenblatt (2010) provided results that showed that the magic formula strategy was able to persistently outperform the United States stock market from 1988 to 2009. This study provides a back-test of the magic formula on stocks listed on the Johannesburg Stock Exchange for the period 1 January 1998 to 31 December 2013. The return was benchmarked against the FTSE/JSE J203 All Share Total Return Index and several other popular value investing strategies over the same period. It was found that, even after adjusting for risk, the magic formula was able to consistently outperform the market index. While the magic formula was able to outperform the market index, it was not the top performing value investing strategy evaluated in this study. The magic formula was outperformed by the combination of size and book-to-market, book-to-market alone, dividend yield, and earnings yield value investing strategies. While the magic formula, and the above mentioned value investing strategies, were able to outperform the market index in terms of overall geometric mean returns, there is not enough evidence to conclude that these value investing strategies outperformed the market index by a statistically significant margin.
275

Estimating the negative impact of noise on the returns of cap-weighted portfolios in various segments of the JSE

Van der Merwe, Rachelle 04 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2015. / ENGLISH ABSTRACT:The main aim of this study was to determine the effect of unanticipated information, or noise, on the returns of cap-weighted portfolios in various segments of the JSE for the period 1995 to 2014. Capital Market Theory states that the optimal ex ante portfolio comprises all shares in a market/segment weighted by ex ante market capitalisation. The optimal ex ante portfolio is however rarely the optimal ex post portfolio, because it is underweighted in shares that will unexpectedly become ‘winners’ during the investment period and overweighted in those that will become ‘losers’. According to Fuller, Han and Tung (2012), all investors in a segment would gain maximum alpha from a portfolio weighted by ex post market capitalisation – in other words, a ‘perfect foresight’ (PF) portfolio. The excess return of the PF portfolio over the benchmark portfolio therefore is an estimate of the negative effect of noise on the return of the benchmark portfolio. In this study, the returns of PF portfolios were compared with the All Share, Large Cap, Mid Cap, Small Cap, Financials, Industrials and Resources segments of the JSE. Intuitively, information to guide decisions on portfolio weighting would be more valuable and deliver more profit when the cross-sectional standard deviation of share returns is high. A secondary aim was therefore to investigate the correlation between cross-sectional standard deviation and PF excess return. It was found that a strong positive correlation (more than 88%) existed between cross-sectional standard deviation and PF excess return in all segments. In ascending order of cross-sectional standard deviation and PF excess return, the results for the segments were Financials (25% and 5%), Resources (28% and 6%), Large Cap (29% and 8%), Industrials (30% and 9%), All Share (32% and 9%), Mid Cap (36% and 13%) and Small Cap (43% and 17%).
276

Copper and zinc uptake by celery plants grown on acidic soil amended with biosolids

Haghighi, Maryam, Pessarakli, Mohammad 11 September 2015 (has links)
For trace elements, such as copper (Cu) and zinc (Zn), the bioavailability of these elements, Cu and Zn, in biosolids is important because both are essential elements and both are potential contaminants when biosolids are land applied. A greenhouse study was conducted in factorial experiment based on a completely randomized design (CRD) with four replications on a soil treated with four rates of Cu (0, 50, 100, and 150 mg/kg) and four rates of Zn (0, 150, 300, and 450 mg/kg) on celery plants to investigate the distribution and mobility of these elements as well as growth and antioxidant changes of celery. The results of antioxidant changes were inconclusive due to irregular changes with Zn and Cu applications. However, generally the results show that Cu did not affect superoxide dismutase (SOD) or peroxidase (POD) activities in most of the treatments. On the other hand, Zn stimulated SOD and POD activities in most of the treatments. The photosynthesis rate decreased with the applications of Cu and Zn at the rates above 100 and 300 mg/kg and increased in low Cu concentration (50 mg/kg) compared to S (soil without biosolid).
277

Εκτίμηση καρδιακού ρυθμού με επεξεργασία σημάτων video σε λειτουργικό σύστημα Android

Χρόνης, Δημήτριος 17 July 2014 (has links)
Αντικείμενο της παρούσας διπλωματικής εργασίας είναι η ανάπτυξη εφαρμογής για λειτουργικό σύστημα Android, τη μέτρηση του καρδιακού ρυθμού. Αρχικά μελετάται ο καρδιακός ρυθμός σαν λειτουργία του σώματος μας, παθήσεις που οφείλονται ή μπορούν να ανιχνευτούν από αυτόν. Γίνεται αναφορά στις φορητές ηλεκτρονικές συσκευές για τη μέτρηση και τις διαφορετικές τεχνολογίες που χρησιμοποιούν προκειμένου να την πραγματοποιήσουν. Τελικά, αναλύεται η τεχνική της φωτοπληθυσμογραφίας. Έπειτα παρουσιάζεται το λειτουργικό σύστημα Android, αναλύεται η αρχιτεκτονική του καθώς και η αρχιτεκτονική των εφαρμογών που αναπτύσσονται για αυτό το λογισμικό. Παρουσιάζεται η πλατφόρμα ανάπτυξης Eclipse καθώς και οι επιπρόσθετες δυνατότητες που αποκτά με την προσθήκη του πακέτου Android SDK. Τέλος παρουσιάζεται βασικό παράδειγμα εφαρμογής ώστε να μπορεί ο αναγνώστης να εξοικειωθεί με βασικές δομές που χρησιμοποιήθηκαν για την ανάπτυξη της παρούσας εφαρμογής. Παρουσιάζεται επίσης η λογική της εφαρμογής που αναπτύχθηκε. Βασικές αρχές για την ψηφιακή επεξεργασία σήματος όπως αυτές χρησιμοποιήθηκαν για την επεξεργασία του σήματος του καρδιακού ρυθμού αναλύεται αυτόματα από την εφαρμογή και τέλος προβάλλεται ο μηχανισμός εξαγωγής του τελικού συμπεράσματος, δηλαδή ο τρόπος με τον οποίο η εφαρμογή πραγματοποιεί την τελική της μέτρηση. / The subject of the thesis under consideration is the development of an application on the operating system Android,for the heart rate measurement. Initially I studied the heart rate as a function of the human body ailments caused or potentially detected by it.I made reference to any portable electronic devices to measure as well as various technologies used in order to accomplish it. At the last part I analyze the technique of photoplethysmography. I later present the operating system Android and I analyze the general logic and the architecture of the applications developed for this software.I presented the Eclipse development platform and the additional possibilities obtained by adding the packet Android SDK. Finally, I demonstated an example of a user friendly application with basic structures used in the development of this application. I also presented the application logic developed. Basic principles of digital signal processing such as those used for signal processing of heart rate are analyzed automatically by the mechanism and finally the final conclusion, that is the way the application performs the final measurement,is exported.
278

Environmental and parental influences on the body size of N.E. Atlantic herring, Clupea harengus, larvae

Morley, Simon Anthony January 1998 (has links)
Morley, S. A. (1998). Environmental and parental influences on the size of herring larvae. Ph.D. thesis submitted to the University of Liverpool for the degree of Doctor of Philosophy Investigations were carried out into the effects of mean egg dry weight and incubation temperature on the size of larvae from four N.E. Atlantic herring stocks (Buchan, Manx, Clyde and Celtic Sea). Hatching characterisitics (length, weight and yolk volume) of Buchan, Manx and Clyde herring were investigated. The time of hatching was inversely related to incubation temperature, although there was some variation between experiments in the date of peak hatching. The total length of larvae increased through the hatching period. In all experiments mean egg dry weight per female was strongly related to the average length, weight and yolk volume of larvae at hatching. The same regression model could be applied to all stocks. There were, however, stock-specific responses of hatching characteristics to incubation temperature although a reduction in length at hatching at higher temperatures was the most consistent response. Development at low temperature resulted in a modification of the length-weight relationship; larvae of the same weight were longer at lower temperatures. Both the increase in length of larvae during the hatching period and the variation in the timing of peak hatching have implications for the comparison of larvae hatching at different temperatures. The otoliths of Manx herring larvae [from "large" (> 0.33mg mean dry weight) and "small" «0.2Smg mean dry weight) eggs] were marked with either alizarin complexone or calcein so that larvae from pairs of large and small egg batches could be reared under identical conditions (at both 10 and I3.S0C) and relative growth monitored. Within each rearing tank large eggs generally produced larger larvae at hatch (length and weight) with higher growth rates (both weight and length specific). There were significant differences both between eggs from different females and between rearing tanks that confounded the comparisons between rearing temperatures. Fultons Condition factor is not thought to be a good measure of nutritional condition of herring larvae smaller than ISmm total length but may be used as a relative measure of body reserves (ReF) and give an indication of ability to withstand periods of poor feeding. This is indicated by a period of high mortality of larvae hatched from small eggs at 10°C, which corresponded with the time period when these larvae had the lowest body reserves. Video recording of the foraging behaviour of laboratory reared herring larvae was used to investigate differences between the feeding strategies of groups of larvae of the same size but different ages, i.e. fast and slow growers. Slow growing larvae searched larger areas, thus expending more energy, than fast growing larvae, but there was no difference in food acquisition. The difference in behaviour tended to increase through development A simple energetics calculation suggested that approximately 50% of the difference in growth rate could be explained by the extra swimming costs of slower growing larvae. The size of Celtic Sea and Manx herring eggs were experimentally reduced in order to investigate if the volume of yolk in each egg determines the size of hatching larvae. Length at hatch was determined by the volume of yolk in each egg but body weight was not. The development and chemical composition of embryos and larvae needs to be investigated in a further series of experiments. All results are discussed in terms of the influence of larval size on survival.
279

Sorption and weathering properties of naturally occurring chlorites

Gustafsson, Åsa January 2004 (has links)
<p>Chlorite is a ferrous silicate mineral occurring as afracture filling mineral in the Swedish granite bedrock thatsurrounds the area of the candidate Swedish geologicalrepositories for nuclear waste.</p><p>To investigate the importance of chlorites as a naturalbarrier for radionuclide migration sorption of Ni(II) onto anatural chlorite was chosen as the studied system. The sorptionbehaviour was studied using batch technique under differentexperimental conditions by varying the concentration ofbackground electrolyte, pH and initial nickel concentration.Our experiments showed that sorption is dependent of pH; belowpH 4 no sorption occurs and in the pH range 7-11 the sorptionmaxima was found. The sorption shows no dependence of ionicstrength in our experiments and together with pH dependency weconclude that the sorption of nickel to chlorite is mostlyoccurring through surface complexation. The distributioncoefficient, K<i>d</i>, was determined for our results and in the range formaximal sorption the K<i>d</i>is approximately 10<sup>3</sup>cm<sup>3</sup>/g.</p><p>Our experimental data were described using a diffuse doublelayer model, including strong and weak surface sites, in thesoftware PHREECQ and the results obtained from PHREEQC werealso used for a fit of the data in the software FITEQL. Thesurface complexes that dominate the sorption of nickel tochlorite from our model are Chl_ONi<sup>+</sup>(weak) and for pH above 9 Chl_ONi(OH)<sup>-</sup>(weak). Flow-through technique was used in ourinvestigations regarding the dissolution rate of a naturalchlorite and the experimental results show that the dissolutionrate of chlorite is strongly pH dependent and at pH 2 thehighest dissolution rate (R<sub>Si</sub>) could be determined to 7• 10<sup>-11</sup>mol/(m<sup>2</sup>s) based on silica data.</p><p><b>Keywords:</b>chlorite, nickel, sorption, surfacecomplexation, dissolution rate.</p>
280

Interaction of turbulent plumes

Kaye, Nigel Gregory January 1998 (has links)
No description available.

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