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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.
41

The development and evaluation of computer vision algorithms for the control of an autonomous horticultural vehicle

Southall, John Benjamin January 2000 (has links)
No description available.
42

Combining georeferenced physical and chemical soil data to improve agronomic and environmental efficiency

Zaman, Qamar-Uz January 1999 (has links)
No description available.
43

RAPID ADAPTATION OF REACTIVE FORCE CONTROL WHEN LIFTING OBJECTS

Markovik, SIMONA 04 February 2013 (has links)
The control of object manipulation tasks involves the close interplay of predictive and reactive control mechanisms. For example, when lifting an object, people typically predict the weight based on object size and material as well as sensorimotor memory obtained from previous lifts of the object. When lifting objects with a precision grip, people increase vertical load force to a target level that slightly exceeds the predicted weight. When the object is heavier than expected, the mismatch between expected and actual tactile signals associated with lift-off triggers a corrective action within ~100 ms, that involves probing increases in load force that continue until the object is lifted. Here we investigated whether this correction action can be adaptively influenced by experience. Participants repeatedly lifted an object that was instrumented with force sensors to measure the forces applied by the fingertips, with weight that could be varied without the knowledge of the participant. In 80% of trials, the weight was set to 2 N and, in different blocks of 110 trials, the remaining 20 % of trials (2 trials randomly selected from each successive 10 trials) was set to either 4 or 6 N. We found that the rate of change of the reflexively triggered increase in load force that occurred in the 4 or 6 N trials, scaled with the additional weight. That is, following the initial increase in load force to ~2 N, the subsequent increase in load force was more rapid for the 6 N object than the 4 N object. In contrast, the onset time of the reactive increase in load force was independent of the additional weight. Finally, this adaptation of reactive load force control took place quickly and was evident after only a few lifts of the heavier weight. These results indicate that the reactive increases in load force that occur when a lifted object is heavier than expected can be adapted and tuned, to refine behavior. This further suggests that multiple predictions can be generated about object weight when lifting. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2013-02-02 13:34:20.533
44

Static Polarizability Measurements and Inertial Sensing with Nanograting Atom Interferometry

Gregoire, Maxwell David, Gregoire, Maxwell David January 2016 (has links)
I used a Mach-Zehnder atom interferometer to measure the static electric-dipole polarizabilities of K, Rb, and Cs atoms with 0.11\% uncertainty. Static polarizability measurements serve as benchmark tests for 𝑎𝑏 𝑖𝑛𝑖𝑡𝑖𝑜 atomic structure calculations. Calculating atomic properties such as polarizabilities, van der Waals coefficients, state lifetimes, or oscillator strengths involves accurately calculating the valence electrons' electric-dipole transition matrix elements. Additionally, testing Cs atomic structure calculations helps interpret the results of parity non-conservation experiments, which in turn places constraints on beyond-the-standard-model physics. I discuss improvements to our experiment that allowed us to measure static polarizabilities with 0.11% uncertainty, and we present our results in the context of recent 𝑎𝑏 𝑖𝑛𝑖𝑡𝑖𝑜 and semi-empirical static polarizabilities and recent, high-precision measurements of excited state lifetimes and van der Waals C₆ coefficients. I also used our interferometer to develop a new technique for inertial sensing. High precision, portable, atom-interferometer gyroscopes and accelerometers are desirable for self-contained inertial navigation and in the future may be used for tests of General Relativity and searches for gravitational waves using satellite-mounted inertial sensors. Satellite-mounted atom interferometers are challenging to build because of size, weight, power, and reliability constraints. Atom interferometers that use nanogratings to diffract atoms are attractive for satellite-mounted inertial sensing applications because nanogratings weigh approximately nothing and require no power. We developed a new 𝑖𝑛 𝑠𝑖𝑡𝑢 measurement technique using our nanograting atom interferometer, and we used it to measure inertial forces for the benefit of our static polarizability measurements. I also review how to calculate the sensitivity of a nanograting atom interferometer, and I employed these calculations in order to design a portable, nanograting atom interferometer inertial sensor.
45

Plymouth Precision Teaching Project (2007-08) : an investigation into student, staff and practice outcomes

Roberts, William George January 2009 (has links)
This thesis describes an investigation into the outcomes of a developmental project focussed on improving the word reading skills of a group of (n=77) secondary school students across five different school settings in a South West of England Local Authority. The 'Plymouth Precision Teaching Project' was conducted during the 2007/8 academic year commencing in September 2007 through to April 2008. The project involved the delivery of regular Precision Teaching (PT) programmes across two cohorts (1 and 2) of students by Teaching Assistants (TAs) in each school who themselves received ongoing training and support throughout the project. This thesis reports on three inter-connected aspects of research stemming from the project: Aspect One considered the impact of PT interventions delivered by trained TAs on groups of secondary school students with literacy learning needs through a quasi-experimental design. Aspect Two investigated the adaptations made by TAs within PT programmes to improve student word reading skills; from here a framework for systematic teaching adaptations was formulated, trialled and reviewed. Aspect Three drew on the experiences of school staff and their learning throughout the initiative. The value of participating in the research was investigated through exploring TAs’ reflections on the development of their understanding of the processes and practices surrounding ‘teaching and learning’. Outcomes of the research point to the continuing contribution of PT to addressing basic reading skill needs through heightened structure to intervention delivery, promotion and scrutiny of ‘treatment fidelity’ and an ongoing, systemic approach to the development of staff skills. This thesis also emphasises the mutual benefits that a collaborative project such as this can bring about; not only can staff contribute to the development of intervention approaches and provide high-quality interventions, but they can also develop their professional knowledge too. As a venture networking schools, a local authority educational psychology service and a university department, it is suggested this thesis reflects a description of the ground modernised educational psychology services should seek to occupy more and more.
46

A Precision Angular Correlation Table and Calculation of Geometrical Correction Factors

Rowton, Larry James 01 1900 (has links)
In recent years y-y angular correlations have been very useful in confirming the spins of excited nuclear states. Angular correlation techniques have also been employed to study the electric and magnetic character of excited nuclear states. With these things in mind, it was decided to design, construct, and test a precision angular correlation table.
47

Improving production agriculture efficiencies and profitability through the development of new planting technologies

Turner, Steven Dale January 1900 (has links)
Master of Agribusiness / Department of Agricultural Economics / Arlo Biere / With a large portion of U.S. farm production expenditures related to the cost of fertilizer, seed, and chemicals, producers within the Corn Belt region are looking for new methods and/or planting processes that would deliver higher levels of production efficiencies and lower operating costs. Specifically within the planting operation, Corn Belt producers are faced with the challenge to better manage the higher cost of crop inputs in order to sustain profitability. The primary objective of this thesis is to examine new planting technologies that would better manage planting applications while directly lowering related input costs. Another objective is to understand through regression analysis how various planting variables affect yield potential. Results from the regression analysis illustrate how the various planting variables affect yield and show the importance of “realtime” planter management, advancements possible only with the new planter technology. Customer surveys and several on-site customer visits were conducted throughout the Corn Belt to better understand the actual needs of producers for new planting technologies. Throughout the customer visits, specific questions about the producers’ planting operation were asked to find new ways for precision technology to help increase overall productivity and ultimately profitability. Producer comments and feedback were analyzed through Quality Functional Deployment (QFD) practices and aligned into product development programs. The products developed from the customer research will help producers in the Corn Belt to reduce corn production inefficiencies and, potentially, increase profit margins, assuming profit levels remain steady and/or increase in lieu of reduced input costs.Farm level net present value (NPV) analyses of new planting technologies were performed. Corresponding yield data from efficiencies gained in seed corn placement and control during “real-time” planting applications were integrated into the NPV analyses along with the precision technology costs. The NPV results were positive.
48

The role and therapeutic potential of extracellular vesicles in atherosclerosis

Nguyen, Nhi 13 June 2019 (has links)
Atherosclerosis, the pathophysiology of many cardiovascular diseases (CVD), is a chronic inflammatory process caused by the sustained accumulation of cholesterol, followed by endothelial dysfunction, and the resulting vascular inflammation. The established treatment for atherosclerosis, to date, involves the use of statins. These medications are hydroxymethylglutaryl coenzyme A reductase (HMG-CoA) inhibitors and lower the levels of by inhibiting HMG-CoA, a rate limiting step in the biosynthesis of cholesterol. Statin therapy varies in effectiveness based on dosage and individual differences, making effective treatment of patients challenging. More recently, extracellular vesicles (EVs) have emerged as a promising field in cardiovascular research. Once thought of as “platelet dust,” EVs are now recognized for their potential as therapeutic targets and tools. In this review, a comprehensive characterization of EVs is provided to explain how EVs are involved in normal physiological function and pathological processes of atherosclerosis. Evidence supports a model where EVs participate in the initiation and progression of atherosclerosis and may also be used as a delivery tool in disease therapy. Currently, cell-derived EVs can be therapeutic agents in animal models, an effective tool in gene therapy, or a drug delivery vehicle. Future experiments enhancing the therapeutic potential of EVs promise to deepen our understanding of EV-based therapy for atherosclerosis precision medicine.
49

Precision medicine in oncology: a complicated idea needs a simple solution

Benson, Adam 17 June 2016 (has links)
Cancer therapy has historically been determined by a tumor’s tissue of origin. Now, thanks to advances in genomics technology, scientists are looking further into one’s cancer; into the very genome that drives the tumor growth. The growth of genomics in cancer research has been astronomical. In a little over ten years since the completion of the Human Genome Project, genomic profiling technologies have developed into an incredibly powerful, relatively cheap, and immensely underutilized tool for oncologists. In the midst of the advances in cancer profiling, there has been reluctance from oncologists to incorporate genomic profiling into their treatment decisions. Saddled by outdated clinical trial designs, and cancer drug regulation programs, the true measure of the clinical utility of genomic profiling has yet to be seen. Cancer scientists will continue to profile cancers at a pace well beyond the limits of the field of oncology. Without coordinated efforts to update the oncology healthcare system, compendia of data will continue to be generated with limited ability to translate the information into personalized medicines. There are significant barriers to overcome before genomic data can universally be incorporated into the daily practice of cancer medicine. In the meantime, resources are available for physicians to help begin the process of integrating a more personalized approach to cancer therapy. Third-party bioinformatics companies are in the best position to be the agents of this change. As cancer research continues to adopt a genomic approach, it is paramount that, for the sake of millions of cancer patients, the healthcare system adapts in a way to best utilize this new information.
50

A precision measurement of the rate of muon capture on the deuteron

Luo, Xiao 13 February 2016 (has links)
Because quantum chromodynamics (QCD) is non-perturbative at low energies, strong in- teractions at the ∼ GeV scale are very challenging to understand. Theoretical progress has been made recently using QCD-based effective field theories (EFT). The short-distance physics of the effective theory is absorbed into a limited number of low energy constants (LECs), which are determined by direct experimental measurement. The MuSun experi- ment is measuring the rate Λd for muon capture on the deuteron, which is the simplest weak interaction in a two nucleon system. Λd will be used, in turn, to better determine a funda- mental LEC known as dR in the EFT. An improvement in the precision of this LEC will improve our understanding of several other processes in the two-nucleon sector: pp fusion, the main source of energy in the sun and other main-sequence stars and neutrino-deuteron scattering, as observed in the SNO experiment. The MuSun experiment determines Λd via a precision measurement of the negative muon lifetime in deuterium. The time difference between an incoming muon, which stops in deuterium, and the subsequent decay electron characterizes the muon disappearance rate. That disappearance rate is the sum of the ordinary muon decay rate and the nuclear capture rate. The ultimate goal of the MuSun experiment is to determine the nuclear capture rate (Λd) to a precision of 1.5 %, an order of magnitude improvement over previous efforts. The principal experimental development required to achieve this goal is a cryogenic (T ∼30K) time projection chamber, which not only serves as the deuterium gas target, but also provides an unambiguous measurement of muon stopping position - muons that stop in high Z materials outside the fiducial deuterium volume produce a very large systematic error. The low temperature helps minimize several other systematic errors. The MuSun experiment is taking place at the Paul Scherrer Institut in Villigen, Switzer- land. Over the past 5 years, the MuSun collaboration has staged 4 major experimental production runs. In this thesis, I present a measurement of the muon capture rate on deu- terium, as determined from data taken in the summer of 2013. The estimated statistical and systematic error is about 7.5%.

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