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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

Modeling and Testing of a Series Elastic Actuator with Controllable Damping

Iyer, Sidharth Suresh 11 January 2012 (has links)
Compliant Actuators are much safer than traditional stiff joint actuators, but at the cost of high overshoot, positional accuracy, and speed. A damper that varies its damping torque during motion is introduced to alleviate these downsides. The equations of motion for the system are derived and simulated. The simulations demonstrated a decrease in the overshoot and ringing time. A physical proof of concept was manufactured and tested. The results from the physical model were inconclusive due to a fault in the physical model. A more accurate physical test model is proposed, and is simulated.
12

Engineering applications of soil information system (sis): precision irrigation and drainage systems design

Ceylan, Bilge Kagan 15 May 2009 (has links)
The objectives of this internship were to demonstrate and apply the knowledge and technical training obtained during Doctor of Engineering coursework and to become familiar with the organizational approach to problems. These objectives were fulfilled in three commercial research and development projects in the field of precision agriculture. The first project involved optimization of a center pivot irrigation system in coordination with the system’s manufacturing company in order to apply irrigation water to maintain uniform soil water content across the field. An optimization-simulation model was developed for this purpose using a dynamic programming approach. The simulations run by the optimization model showed that the existing pivot speed prescription resulted in a more uniform soil water content across the field reducing the crop yield losses. The objective of the second internship project was to analyze the agricultural drainage industry for identification of the potential applications of the spatial soil information into agricultural drainage design and construction. In order to accomplish this task, a comprehensive literature survey was conducted with an emphasis on the drainage approximate equation and numerical methods. Software tools that are currently employed in drainage design and construction were evaluated. A detailed market analysis was conducted with a focus on the industry stakeholders. A strategic strengths, weaknesses, opportunities and threats (SWOT) analysis was conducted for the agricultural drainage industry using Porter’s five forces method. The last internship project involved investigation of the potential for using soil information obtained by SIS in the assessment of soil salinity. A correlation analysis was conducted between the soil paste extract electrical conductivity values measured in the laboratory on collected soil samples and those estimated using the soil resistivity values collected by the SIS, which is a measure of soil salinity. The results showed no clear correlations. While the internship projects provided the intern the opportunity to apply some of the analytical methods learned as part of the Doctor of Engineering coursework, they also provided invaluable experience for the intern to understand research and development projects in a business environment, which was one of the major objectives of the internship.
13

Precision guided munitions : constructing a bomb more potent than the A-bomb /

Gillespie, Paul G., January 2002 (has links)
Thesis (Ph. D.)--Lehigh University, 2002. / Includes vita. Includes bibliographical references (leaves 261-272).
14

The long road to Desert Storm and beyond the development of precision guided bombs /

Blackwelder, Donald I. January 1900 (has links)
Thesis--School of Advanced Airpower Studies. / Title from title screen (viewed Oct. 9, 2003). "May 1992." Includes bibliographical references.
15

A study of the decay τ → π⁻ π⁻ π⁺ π⁰ π⁰ ν(τ) using the BaBar detector

Edgar, Christina Louise January 2008 (has links)
A study of the decayτ → π⁻ π⁻ π⁺ π⁰ π⁰ ν(τ) is presented. The results presented here could be used to inform and improve the Monte Carlo simulations.
16

Geographic information systems in the application of precision agriculture for sustainable sugarcane production in the Republic of Panama

Mazumdar, Sohinee. January 1900 (has links)
Thesis (M.Sc.). / Written for the Dept. of Bioresource Engineering. Title from title page of PDF (viewed 2008/05/14). Includes bibliographical references.
17

Precision farming in South Africa

Rusch, Peter C. January 2001 (has links)
Thesis (M.Eng.)(Agricultural)--University of Pretoria, 2001. / Title from opening screen (viewed March, 18, 2005). Includes summary. Includes bibliographical references.
18

Sowing Sustainable Agriculture: Investigating "Sustainability" in the Academic Discourse on Precision Agriculture

Orzel, Emma Catherine 14 February 2024 (has links)
The academic literature suggests that precision agriculture (PA) is revolutionizing the agricultural sector, with claims that it can enhance sustainability through technological advancements such as tractors with automated guidance, sensor suites, satellites, and drones. The literature on PA widely asserts PA has sustainability benefits claiming that these emerging agricultural technologies will address food system challenges. These challenges include improving the state of food security in the face of a growing global population and the ongoing threats of climate change and environmental degradation caused by agriculture by enhancing agricultural efficiency, productivity, and profits for farmers. Despite this pervasive notion of an inherent link between PA and sustainability, questions persist regarding the substantiation of these "sustainability" benefits, particularly in the promotion of these technologies. To investigate this link between PA and sustainability, this thesis considers the following research questions: What are the key factors and influences that have contributed to the enduring connection between PA and sustainability within the academic literature and how is the concept of sustainability conceptualized and operationalized within the academic discourse on PA? Employing an inductive constructivist perspective, this research examines academic literature collected through systematic literature review and interview transcripts from semi-structured interviews with key informants from academia, to explore the dominant models of sustainability present in the literature and the factors that have contributed to the formation of this inherent link. Drawing on this constructivist perspective, the research demonstrates that sustainability is not an inherent aspect of PA but rather a construct shaped by the various actors responsible for the promotion of PA. This implies that those actively advocating for or endorsing PA, construct the understanding and portrayal of sustainability in relation to PA, leading to a convergence of sustainability conceptualizations reflective of existing productivist paradigms in agriculture. Considering these findings, this thesis contributes to the greater literature which asserts that PA, although full of promise, may reinforce the issues created by contemporary agriculture.
19

Nitrogen variability assessment in tomatoes using the remote sensing technique for precision farming

Bodirwa, Kgashane Bethuel January 2009 (has links)
Thesis (M.Sc. (Agriculture)) --University of Limpopo, 2009 / The purpose of the study was to assess nitrogen variability in tomato using the Remote Sensing Technique. The assessment was carried out through three growth stages (seedling, 50% flowering, and 50% fruiting stage). The GreenSeeker optical sensor unit that records NDVI values and total leafy nitrogen analyzer, “The Primacssn Nitrogen Analyzer,” was used in this study for data collection. Fertilizers were applied to the soil (Urea - 46% N, Superphosphate) every two weeks in the pots only for the treated experiment, and no nitrogen application for the untreated experiment. Tomato cultivars Flora Dade and Roma VF were used during the experimentation. The mean NDVI values for cultivars Flora Dade and Roma VF were 0.83 with N application. This value was 0.81 without N-application. The mean N-content for cultivars Flora Dade and Roma VF were 3.30 g/plant with N application. This value was 2.94 g/plant without N-application. The cultivar Flora Dade with N applied had higher N-content (3.38 g/plant) than the cultivar Roma VF with 3.22 g/plant when no N is applied across the three growth stages. The number of fruits’ means values at 50% fruiting stage for cultivars Flora Dade and Roma VF were 8.9 fruit per plant with N application. These mean values were 5 fruit per plant without N application. It was also evident that plants likely to have lower N content (untreated) had delayed maturation unlike those with nitrogen applied (treated), which had rapid/early maturation. Untreated plants took an average of 120 days till maturity, whereas the treated plants took an average of 100 days till maturity. Ground measurement of NDVI by the GreenSeeker sensor in this study showed potential for assessing nitrogen variability in tomato. / National Research Foundation
20

Kartläggning av tillslagsprecision i fotboll

Alf, Viktor, Lindberg, Linus January 2015 (has links)
Syfte Syftet med studien är att analysera tillslagsprecision i fotboll och jämföra eventuella skillnader mellan juniorer och seniorer på både herr- och damsidan. Metod Totalt 30 elitspelare varav 16 herrar och 14 damer utförde tester i tillslagsprecision. De färdigheter som testades var passning och skott. Upplägget var 60 skott (30 stillaliggande och 30 halvvolley) och 80 passningar (20 stillaliggande bästa fot, 20 rullande bästa fot, 20 stillaliggande näst bästa fot och 20 rullande näst bästa fot). Testresultaten analyserades via Excel och Kinovea, där kunde medelvärden och standardavvikelser för varje testperson och testgrupp räknas ut. Resultat Resultatet visar att det endast var signifkant skillnad på ett av sex moment vad gäller tillslagsprecisionen på herrsidan. På damsidan var det ingen signifikant skillnad på något moment. Slutsatser Författarna har i denna studie identifierat en platå mellan spelare i åldrarna 16-18 år och seniorspelare vad gäller tillslagsprecision. Spelare i åldrarna 16-18 är lika bra som seniorspelare på de individuella färdigheterna passning och skott. Denna platå kan vara resultatet av för lite individuell träning, sk isolerad träning vad det gäller tillslagsprecision, på föreningsträningarna. Om föreningstränarna följer den utbildning SvFF ger dem ska endast två minuter per träning gå till varje individuell färdighet (13 st enligt SvFF). Bristen av tid för dessa färdigheter kan vara en avgörande faktor för att utvecklingen av tillslagsprecision står stilla idag. / The aim of this study is to analyze if the precision of a shot and a pass differs between professional youth players (16-18 years) and senior players (22+ or older). Method A total of 30 elite players which were 16 males and 14 females performed tests in shooting and passing precision. The set-up on the test days were a total of 60 shots(30 lying still and 30 half volley) and 80 passes (20 lying still best foot, 20 rolling best foot, 20 lying still next best foot and 20 rolling next best foot). The test results were analyzed using Excel and Kinovea. In these programs the mean value and standard deviation for each player and test group could be calculated. Results The result shows that there were only significant differences in one of six parts regarding precision on the men's side. On the women's side, there was no significant difference in any of the six moments. Conclusions The authors of this study identified a plateau between players aged 16-18 and senior players in terms of accuracy in passing and shooting. Players between the ages of 16-18 is as good as a senior player at the individual skills passing and shooting. This plateau can be the result of too little individual training so called isolated training in terms of precision. If the club coaches follow the training SvFF educate, only two minutes per training session goes to each individual skill (SvFF names 13 skills). The lack of time for these skills can be a decisive factor for why the development of precision stands still today.

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