• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 604
  • 429
  • 79
  • 58
  • 43
  • 34
  • 33
  • 13
  • 11
  • 10
  • 6
  • 4
  • 4
  • 4
  • 4
  • Tagged with
  • 1518
  • 535
  • 509
  • 425
  • 179
  • 179
  • 167
  • 151
  • 119
  • 116
  • 105
  • 92
  • 89
  • 89
  • 88
  • 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.
91

Approaches for Developing and Implementing Precision Feeding Programs to Maximize Feed Efficiency

Price, Tanner Paige 18 May 2020 (has links)
Nutritional management of dairy cattle is of importance to the industry due to its influence on production performance and association with large expenses for producers. Current ration formulation may be improved by predicting feeding recommendations for individual animals, rather than groups of animals, through precision feeding. Automated feeding systems (AFS) designed to deliver individual rations must include response-based models that utilize individual cow production data to make feed recommendations. These models require large data sets of individual cow responses to a variety of nutritional interventions. As a result, an experiment was designed to collect individual response data from 24 Holstein cows fed supplemental top dresses. After analyses, dry matter intake (DMI), milk yield (MY), milk fat yield, milk protein yield, feed efficiency, and activity were significantly affected by top dress (P < 0.001). These results suggest opportunity to use precision feeding to implement economically optimal ration recommendations designed to increase dairy cow production. Therefore, a second experiment was conducted in order to develop and test two algorithms that targeted individualized feeding to increase feed efficiency. Milk protein percentage (P = 0.008) and feed efficiency (P < 0.001) were significantly affected by a 3-way interaction between top dress, algorithm, and week. These results highlight the opportunity for precision feeding to increase the efficiency of individual dairy cows. Although the control group resulted in greater income over feed costs than either of the developed algorithm feeding strategies, algorithm refinement and modification may result in more efficient feeding recommendations that are economically viable. / Master of Science / Nutritional management of cattle is crucial to the dairy industry. The feeding of dairy cattle is the largest expense for producers and directly influences cow production. In particular, precision feeding of dairy cattle may have the ability to lower costs for farmers and increase the productivity of dairy cows. Currently, cattle are fed in group configurations, where cows with similar nutrient requirements are offered the same diet. However, individually feeding dairy cows utilizing precision technologies may have the ability to increase the production performance of cattle. Utilizing precision feeding to individually feed dairy cattle requires automated feeding systems (AFS) designed to decrease the additional labor associated with feeding animals as individuals. However, algorithms designed to predict individual animal nutrient requirements are lacking for use in AFS. As a result, large data sets of individual cow responses to varying diets are necessary to train algorithms designed to predict unique ration formulations for individual animals. Two experiments were developed to collect individual animal production responses that were used to develop two response-based algorithms capable of influencing feed efficiency of individual cows. The results from these experiments highlight the potential for precision feeding of dairy cattle to influence individual animal feed efficiencies and milk production. Future improvements in algorithm development and training are necessary in order for these feeding strategies to be economically worth the investment of AFS on commercial dairy farms.
92

Development of a Precision Mite Management Program for the Control of the Ectoparasite Varroa destructor in Hives of Apis mellifera L.

Means, Jackson C. 03 June 2014 (has links)
The European honey bee, Apis mellifera, is an important pollinator of horticultural and agricultural field crops, providing ≈ 90% of all commercial pollination services (Genersch et al. 2010). The recent rise in colony loss due to Colony Collapse Disorder (CCD) has been a source of concern for both beekeepers and the apiculture industry. One of the factors implicated in CCD is infestation by the ectoparasitic mite, Varroa destructor. Initial efforts to control the mite relied heavily on regular application of miticides without regard to actual mite infestation levels. This approach has led to problems of resistance in the mite and contamination of the hive and hive-products. Because it is unlikely that miticides will be removed as an option for mite management, a precision mite management (PMM) approach using information on the spatiotemporal distribution of the mite to improve sampling and treatments is seen as a viable option, particularly with respect to treatment costs and impacts on the environment. The primary objective of this study was to develop an understanding of the spatiotemporal distribution of the Varroa mite and bee brood within hives for the purpose of developing a PMM approach for the mite. Varroa mite populations were sampled from May to June, 2012 and February to October, 2013. Sampling was conducted with three commonly used sampling methods: soapy water roll (SWR), brood uncapping, and a modified sticky board; brood uncapping, however, was discontinued during the study due to hive the labor cost and harmful effects of this method to the hives. Similar trends in mite population levels were observed using the soapy water roll and sticky board sampling methods. Spearman's nonparametric analysis showed that there was a significant correlation (ρ = 0.47, P<0.001) in mite population levels for the soapy water roll and sticky board methods for sampling conducted from February to September, 2013 (the SWR method was not used in October). This was despite the fact that there was no significant correlation (ρ= -0.03, P = 0.8548) between the two sampling methods during the spring sampling period from February to April, 2013. The observed lack of correlation between the two sampling methods in early spring was likely due to the low population of brood in the hive, which caused the majority of the mites to remain on adult bees. Mites per 100 adult bees, therefore, appear to reflect mite population levels within the hive more closely than mite fall on sticky borad during the February to April sampling period. This suggests that the soapy water roll method is a better method for estimating mite population levels within the hive in the early spring compared with the sticky board method. Geospatial analyses of the distributions of mite fall on the sticky boards were conducted using geostatistics and Spatial Analysis by Distance IndicEs (SADIE). Both analyses showed that mite fall on the sticky board was generally aggregated and the aggregation increased with mite population levels. The average range of the variogram from geostatistical analysis was estimated at 4 sticky board cells; this range value was increased to 5 cells and was used to develop a systematic outside-range sampling protocol for mites on a sticky board. The results showed that the accuracy of the systematic outside-range sampling compared well with that of the traditional sticky board counting method in estimating total mite fall, but required only 60% of the effort (i.e., counting 63 instead of 105 cells). SADIE analysis showed that there is an overall association between the distribution of mite fall on a sticky board and the distribution of brood within a hive. A greater degree of correspondence was also observed in the association of drone and mite distributions during May to June; greater correspondence in worker brood and mite associations was observed in August and September. These differences may be due to relative amounts of the two types of brood present within the hive. A test of the efficacy of precision application of Varroa mite treatment based on the association between drone brood and mite fall resulted in a significantly greater reduction in mite levels on the sticky board using a traditional miticide treatment method compared with the control and precision treatments (𝜒2 =362.571; df = 2; P <0.0001); mite population levels with the precision method, however, were significantly reduced compared with the control. / Master of Science in Life Sciences
93

Unmanned Aerial System for Monitoring Crop Status

Rogers, Donald Ray III 11 January 2014 (has links)
As the cost of unmanned aerial systems (UAS) and their sensing payloads decrease the practical applications for such systems have begun expanding rapidly. Couple the decreased cost of UAS with the need for increased crop yields under minimal applications of agrochemicals, and the immense potential for UAS in commercial agriculture becomes immediately apparent. What the agriculture community needs is a cost effective method for the field-wide monitoring of crops in order to determine the precise application of fertilizers and pesticides to reduce their use and prevent environmental pollution. To that end, this thesis presents an unmanned aerial system aimed at monitoring a crop's status. The system presented uses a Yamaha RMAX unmanned helicopter, operated by Virginia Tech']s Unmanned Systems Lab (USL), as the base platform. Integrated with helicopter is a dual-band multispectral camera that simultaneously captures images in the visible and near-infrared (NIR) spectrums. The UAS is flown over a quarter acre corn crop undergoing a fertilizer rate study of two hybrids. Images gathered by the camera are post-processed to form a Normalized Difference Vegetative Index (NDVI) image. The NDVI images are used to detect the most nutrient deficient corn of the study with a 5% margin of error. Average NDVI calculated from the images correlates well to measured grain yield and accurately identifies when one hybrid reaches its yield plateau. A secondary test flight over a late-season tobacco field illustrates the system's capabilities to identify blocks of highly stressed crops. Finally, a method for segmenting bleached tobacco leaves from green leaves is presented, and the segmentation results are able to provide a reasonable estimation of the bleached tobacco content per image. / Master of Science
94

Observation of muscle activation in relationship to digit force production during a precision pinch tracking task

Hamilton, Landon Douglas 15 February 2011 (has links)
The primary purpose of this study was to observe the relationship between muscle activation of the right hand with the force produced at the fingertips in an isometric precision pinch tracking task. Thirty right-handed subjects, 15 males and 15 females, with a mean age 23.5 (SD 3.5) years, free from any neurological disorder or physical ailment, had a pair of electromyography (EMG) electrodes placed over the first dorsal interosseous (FDI) muscle, which acts on the index finger, while performing a pinch force tracking task scaled to 20% maximum voluntary contraction (MVC). The tracking task was chosen because it created a continuously increasing force application to 20% MVC and then decreasing force release from 20% MVC at a prescribed rate in both cases of 6.66% MVC force per second. In addition to showing increases in EMG activation of the FDI with increases in force, the results revealed that muscle activation for a given force level was generally greater for force application than for force release. This may be due dynamics of muscle contraction or to patterns of multiple muscle coordination. / text
95

A FEASIBILITY STUDY OF OPENING AND OPERATING A PRECISION FARMING FIRM IN KENTUCKY

Logsdon, Thomas Joseph 01 January 2006 (has links)
In the recent past precision farming has become increasingly popular amongfarmers. However, little has been done to study the business aspect of precision farming,with most research focusing on the production side. This purpose of this thesis is tostudy the feasibility of successfully opening and operating a precision farming firm inKentucky. To determine the feasibility of such a venture a computer model was createdand a producer survey was designed and distributed to farmers in Western and CentralKentucky.The purpose of the computer model was to determine the factors that wouldinfluence the successful operation of a precision farming firm including number of acresserviced per year, pricing of services, the cost of capital to borrow money, and manyother factors. A break-even analysis was performed to determine what kind of annualincreases in business would be required, what price range services should be in, and atwhat interest rate money could be borrowed and a simulated precision farming firm couldstill operate successfully.The producer survey was mailed to 336 farmers in Western and Central Kentuckybecause of their geographical locations and the type of crops that are grown there. Thesurvey response rate was 20 percent and of the 66 surveys that were returned 59 wereappropriate and useful for research. After compiling the results of the surveys,regressions were run to determine any correlation between dependent and independentvariables that affect the adoption rate of precision farming techniques. The results foundthat a negative correlation exists between age adoption rates of precision farming and thata positive correlation exists between farm size and adoption rates of precision farming.After conducting the research, it is believed that given the right economicconditions and management a precision farming firm is very capable of thriving inKentucky. However, the workforce must be very motivated and capable of constantlyrecruiting new clients to adopt precision farming.
96

Precision Agriculture Technology Adoption and Usage in North Dakota

Cossette, Maximillion Kirk January 2019 (has links)
The world population is projected to rise, and there is a growing concern of future food availability. Precision agriculture technologies are one solution to this problem as they aim to produce more food on less land. This study examines the adoption and intensity of precision agriculture technology usage by producers in North Dakota. Data from a North Dakota State University survey was collected and analyzed using an econometric double-hurdle model. Results of the study describe which producers adopt precision agriculture technologies, which technologies complement each other, and what affects the intensity of technology usage. Several technologies were found to have complementary effects on each other, larger farms are more likely to adopt PATs, and crop choices have varying impacts on the adoption and usage of PATs. Most of these findings agree with previous literature, although new light was shed on some new findings and predictions.
97

Evaluation of Recommender System / Utvärdering av rekommendationssystem

Ding, Christofer January 2016 (has links)
Recommender System (RS) has become one of the most important component for many companies, such as YouTube and Amazon. A recommender system consists of a series of algorithms which predict and recommend products to users. This report covers the selection of many open source recommender system projects, and movie predictions are made using the selected recommender system. Based on the predictions, a comparison was made between precision and an improved precision algorithm. The selected RS uses singular value decomposition in the field of collaborative filtering. Based on the recommendation results produced by the RS, the comparison between precision and the improved precision algorithms showed that the result of improved precision is slightly higher than precision in different cutoff values and different dimensions of eigenvalues. / Rekommendationssystem har blivit en av de viktigaste beståndsdelar för många företag, såsom YouTube och Amazon. Ett rekommendationssystem består av en serie av algoritmer som förutsäger och rekommenderar produkter till användare. Denna rapport omfattar valet av många öppen källkod rekommendationssystem projekt, och filmprognoser görs med det valda rekommendationssystemet. Baserat på filmprognoser, gjordes en jämförelse mellan precision och en förbättrad precision algoritmer. Det valda rekommendationssystemet använder singulärvärdesuppdelning som kollaborativ filtrering. Baserat på rekommendationsresultat som produceras av rekommendationssystemet, jämförelsen mellan precision och den förbättrade precisions algoritmer visade att resultatet av förbättrad precision är något högre än precision i olika brytvärden och olika dimensioner av egenvärden.
98

Passningshållet påverkar passningsprecision hos ungdoms- och juniorishockeyspelare / Stick orientation effects passing precision in youth and junior ice hockey players.

Gers, Johnny, Brandow, Marcus January 2019 (has links)
SyfteSyftet med denna studie var att undersöka passningsprecisionen hos ungdoms- och juniorishockeyspelare (15 – 18 år) som under den gångna säsongen var aktiva inom serierna ”Elit” eller ”Division 1” i antingen U16, J18 eller J20.MetodFör att undersöka passningsprecision i ishockey så designades två tester. Testerna gick ut på att försöka träffa en tre centimeter bred målpinne med en puck från ett avstånd på 15 meter. Fem spelare genomförde två test med olika komplexitetsnivåer, en i rörelse samt en stillastående. Varannan passning slogs med forehand och varannan med backhand. Passningarna genomfördes i serier om tio passningar (5 forehand och 5 backhand). På båda stationerna genomförde varje spelare fem serier, det vill säga totalt 50 passningar (25 forehand, 25 backhand).ResultatResultatet i denna studie visade att det fanns en signifikant skillnad i passningsprecisionen mellan forehand och backhand i såväl stillastående (p &lt; 0,001) som i rörelse (p = 0,009). Däremot var det ingen signifikant skillnad beroende av komplexitetsnivå för vare sig forehand (p = 0,29) eller backhand (p = 0,22).SlutsatserUtifrån det resultat som framkom så kan man se att passningshållet (forehand/backhand) påverkar passningsprecisionen. Samtliga spelare hade en högre precision på sin forehandsida jämfört med backhand oberoende av komplexitetsnivå. / PurposeThe purpose of the study was to measure passing precision among youth- and junior ice hockey players between 15 and 18 years of age, who in the past season played at either “elite” or “Division 1” level in U16, J18 or J20.MethodsTo measure passing precision in ice hockey, two tests were designed. The tests consisted of a player trying to hit a three-centimeter-wide pin by passing a puck from 15 meters away. Five players did the test that were divided into two different levels of complexity, one in forward motion and one standing still. The players hit a total of ten passes divided into five forehand passes and five backhand passes, they took turns in hitting forehand and backhand one by one. In total, the players did five series of ten passes on each station, a total of 50 passes divided into 25 forehand passes and 25 backhand passes.ResultsThe result of this study showed that there was a significant difference in passing precision between forehand passes and backhand passes, regardless off whether the pass was played in motion (p = 0,009) or standing still (p &lt; 0,001). However, the test did not show any significant difference between the different levels of complexity on either forehand (p = 0,29) or backhand (p = 0,22).ConclusionsBased on the results from this study, you can see that the way you hit the pass (forehand/backhand) effects the passing precision. All players had a higher precision on their forehand than their backhand, regardless of level of complexity.
99

Verifiering av metoden för PCT-analys på Alinity i-serie Abbot

Adowan, Mohmad January 2023 (has links)
Procalcitonin (PCT) is a precursor protein of the hormone calcitonin and is encoded by the gene Calcitonin-1. In the Blekinge Regional, P-PCT is only analyzed in Karlskrona. The analysis is performed in the department of clinical chemistry on the Alinity i-series instrument. PCT indicates bacterial infections and therefore, it is important to have a backup method for the analysis when the instrument in the city of Karlskrona is out of order. The aim of this work was to verify the analysis method of P-PCT on the instrument Alinity i-series in the city of Karlshamn. Analysis method verification means to confirm and prove that the method meets the specified requirements. Verification was performed by analyzing 35 samples with different concentration of PCT on the master instrument in Karlskrona and on “Alinity 1” and “Alinity 2” in Karlshamn. The method was compared by studying correlation coefficient and bias. The precision was measured only on “Alinity 1” which would be the master instrument in Karlshamn. Precision was measured by analyzing 25 replicates at two control levels and then was 5 replicates of each control level analyzed over 5 days. The correlation was good and no significant bias between results from Karlskrona and “Alinity 1” and between results from “Alinity 1” and “Alinity 2”. Precision on “Alinity 1” meets the requirements. The conclusion was that verification of PCT on master instrument “Alinity 1” and slave instrument “Alinity 2” was approved and the backup method for the PCT analysis in Karlshamn was verified. / Prokalcitonin (PCT) är en peptidprekursor till hormonet kalcitonin och kodas av genen kalcitonin-1 (CALC-1). PCT används som biomarkör för bakteriella infektioner och sepsis. I Region Blekinge analyseras P-PCT bara i Karlskrona. Analysen utförs på avdelningen för Klinisk kemi på instrumentet Alinity i-serie Abbot. PCT indikerar bakteriella infektioner och av denna anledning efterfrågas av flera avdelningar. Därför är det viktigt att verifiera en analysmetod för P-PCT i Karlshamn, ifall instrumenten i Karlskrona är ur funktion. Syftet med arbetet var att verifiera analysmetoden för P-PCT på instrumentet Alinity i-serie Abbot i Karlshamn. Metodverifiering innebär att bekräfta och bevisa att metoden uppfyller specificerade krav. Metodverifiering utfördes genom att analysera 35 prover med olika PCT-koncentrationer på masterinstrument ”Shrek” i Karlskrona och på ”Alinity 1” och ”Alinity 2” i Karlshamn. Metoderna jämfördes genom att studera korrelationskoefficient och bias. Inom och total serie-precision mättes bara på ”Alinity 1” som ska vara masterinstrument i Karlshamn. Inom serie-precision mättes genom att analysera 25 replikat av två kontrollnivåer och total serie-precision genom att analysera 5 replikat/dag under 5 dagar. Resultaten blev att metoden på ”Alinity 1” hade en god korrelation med metoden på masterinstrument ”Shrek” och ingen signifikant bias observerades mellan metoderna. Inom och total serie-precision på ”Alinity 1” uppfyller kraven. Metoden på ”Alinity 2” hade en god korrelation med metoden på masterinstrument ”Alinity 1” och ingen signifikant bias observerades mellan metoderna. Slutsatsen var att verifiering av P-PCT på masterinstrument ”Alinity 1” och slavinstrument ”Alinity 2” var godkänd och därmed verifierades en backupmetod för analysen P-PCT i Karlshamn.
100

Using precision agriculture technology to evaluate environmental and economic tradeoffs of alternative CP-33 enrollments

McConnell, Mark Dewitt 30 April 2011 (has links) (PDF)
United States Department of Agriculture’s Farm Bill conservation programs provide landowner incentives to remove less productive and environmentally sensitive lands from agricultural production and re-establish them in natural vegetation to achieve conservation objectives. However, removal of arable land from production imposes an opportunity cost associated with loss in revenue from commodities that otherwise would have been produced. The Habitat Buffers for Upland Birds practice (CP-33) under the Continuous Conservation Reserve Program is a targeted conservation practice designed to increase northern bobwhite populations in agricultural landscapes. However, establishing CP-33 buffers on profitable farmland may be incompatible with economic objectives of landowners. To determine how CP-33 enrollment influenced field profitability and bobwhite abundance; I simulated CP-33 buffers on crop fields across a range of commodity prices and modeled profitability and predicted bobwhite abundance. CP-33 increased field revenue on a percentage of fields at all commodity prices and increased bobwhite abundance up to 30%.

Page generated in 0.0836 seconds