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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.
111

Uniting genetics and chemistry to reduce the risk of take-all disease in commercial second wheats

Moughan, Joseph January 2017 (has links)
Gaeumannomyces tritici is a soil-borne, highly destructive, wheat root pathogen, causing take-all disease. Some modern, elite, winter wheat cultivars possess a genetic trait promoting low take-all inoculum build-up (LowTAB). This leads to reduced disease if wheat is grown in the same field the next year. This PhD aimed to test if genetics (LowTAB) and chemistry will individually or synergistically influence take-all fungal inoculum build-up in first wheats as methods to control second wheat take-all disease. The underlying mechanism, epidemiology, agronomy and genetics of the TAB (take-all build-up) trait in eight first wheat field trials was investigated. This identified two minor QTLs conferring the LowTAB trait, in a doubled haploid mapping population. This PhD also confirms the highly complex cultivar-year-field interactions that underpin this trait. Root phenotyping experiments in the field and laboratory highlight that the TAB trait is not likely to be the result of root system architecture variation. Future field trials are planned to confirm the QTLs identified and to test for links between TAB and root-soil-microbial interactions. The effect of foliar applied chemistry (fungicide: Amistar, active ingredient: azoxystrobin and plant growth regulator: Moddus, a.i. trinexapac-ethyl) combined with genetics (TAB) on first wheat take-all inoculum build-up and second wheat disease was investigated. To complement this, laboratory screens were performed checking for common target site mutations to the azoxystrobin fungicide, in new and historic G. tritici isolates. For the first time, legacy effects of first wheat foliar chemistry on second wheat disease were identified, however no synergy with genetics were found. Early first wheat Amistar sprays reduced second wheat take-all disease, whilst later sprays and plant growth regulator, Moddus; had no effect. However, first wheat inoculum reduction by Amistar, could not be directly linked to the second wheat disease outbreaks observed. No evidence of fungicide resistance was found in 40 UK isolates, thus the varied efficacy of Amistar is linked to soil dose rate at the different application times. The collective PhD findings of the effect of first wheat chemistry and genetics make a significant contribution to the control of take-all disease in commercial second wheat crops.
112

QUEM ESTÁ AÍ, ONDE ANTES ERA ELE? Representações sociais do cuidar entre familiares de idosos portadores de demência

Gaudencio, Mércia Maria Paiva 22 November 2002 (has links)
Made available in DSpace on 2015-09-25T12:23:04Z (GMT). No. of bitstreams: 1 MerciaMariaPaivaGaudencio.pdf: 1144653 bytes, checksum: f0d6c0e8db35907fc305c12615b0f453 (MD5) Previous issue date: 2002-11-22 / The care/cared relations, even as old as men, remain current and central to the comprehension of the senses attributed to the health/diasease process. On this perspective and in conjunction with the factors related to the population aging, in the demented illness and about the necessary care, it arises the problem of the demented old people family care-talcer. One of the sides of this problem was investigated with the purpose of characterizing the care and the old people, as well as aprehend and analyze the care/cared representation elaborated by this group of subjects. So, the Social Representation Theory was the support and guarantee of a quanti-qualitative approach of multidiscipline charater. The method used resulted in the organization of a coupus compounded by discursive material collecled with the help of twenty care-takers who live in the city of Campina Grande, PB. To collect data it was used a free-association test, semi-structured interview and a quiz to characterize the care-takers and the old sick people. To analyze it was uied a descriptive statistic treatment of the qualilied data and the technique of the collected speech content thematic analysis. Such procedures resulted in the characterization and context of the care-takers and old people and on the identification of 4 categories of care/cared: pragmatic manifestation, afective, philosophical aspect and temporal manifestation. These categories are representatives poles around cuhich articulate and structure representations that show the transformation of the strange, that the dement pictures involve, into a family. It indicales, yet, the results toward the social silence aroud the problem of the old demented people care-takers, and, simultaneously, toward to the necessity of carry on investigations about a theme so close to us, but still so invisible / As relações de cuidar/cuidado, embora tão antigas quanto o homem, permanecem atuais e centrais para a compreensão dos sentidos atribuídos ao processo saúde/doença. Ao refletirmos sobre esta perspectiva e associa-la aos fatores envolvidos no processo de envelhecimento comprometido por uma patologia, no caso a doença demencial, emergiu a problemática do cuidador familiar. Uma das faces deste problema foi investigada, objetivando caracterizar os cuidadores e os idosos, bem como apreender e analisar as representações do cuidar/cuidado elaboradas por este grupo de sujeitos. Para tanto, a Teoria das Representações Sociais foi suporte e garantia de uma abordagem quanti-qualitativa de caráter multidisciplinar. O percurso metodológico empreendido resultou na organização de um corpus constituído por material discursivo coletado junto a vinte cuidadores, residentes na cidade de Campina Grande, PB. Para a coleta de dados foram utilizados um teste de associação-livre, entrevista semi-estruturada e questionário para a caracterização dos cuidadores e dos idosos. Para a análise, recorreu-se ao tratamento estatístico descritivo e à técnica da análise temática de conteúdo. Tais procedimentos possibilitaram a caracterização dos cuidadores e dos idosos, e viabilizaram a identificação de quatro categorias do cuidar/cuidado: manifestações pragmáticas, afetivas, de cunho filosófico e manifestações da temporalidade. Essas categorias são pólos representacionais em torno dos quais se articulam e se estruturam representações que indicam a transformação do estranho, que os quadros demenciais comportam, em familiar. Apontam, ainda os resultados, para o silêncio social em torno da problemática do cuidador de idosos demenciados, e, simultaneamente para a necessidade de se empreender investigações sobre uma temática tão próxima de todos nós, mas ainda tão invisível
113

Logística reversa de resíduos de equipamentos elétricos e eletrônicos: proposta de indicadores de monitoramento para órgãos ambientais / Take-back systems for waste electrical and electronic equipment: proposal of monitoring indicators for environmental agencies

Pereira, Raissa Silva de Carvalho 18 June 2018 (has links)
A Política Nacional de Resíduos Sólidos, de 2010, representou um novo paradigma para a gestão de resíduos de equipamentos elétricos e eletrônicos, responsabilizando fabricantes, importadores, distribuidores e comerciantes pela coleta e destinação adequada desses resíduos por meio de sistemas de logística reversa. Dentro do cenário nacional, o Estado de São Paulo encontra-se em uma posição pioneira frente à implementação da logística reversa. Em âmbito internacional, destacam-se os casos japonês e europeu como referência na gestão de tais resíduos. Nesse contexto, esta dissertação tem o objetivo principal de desenvolver um conjunto de indicadores para avaliação de sistemas de logística reversa de resíduos de equipamentos elétricos e eletrônicos, com a finalidade de contribuir para o acompanhamento e avaliação de tais sistemas pelos órgãos ambientais. Foram realizadas revisão bibliográfica e pesquisa documental sobre os modelos de gestão de resíduos de equipamentos elétricos e eletrônicos e os sistemas de logística reversa na Europa, no Japão e no Brasil, e sobre indicadores e critérios para avaliação de sistemas de logística reversa desses resíduos. Em seguida, foram aplicados questionários para identificar quais indicadores são utilizados para os sistemas europeus e japoneses, quais são sugeridos por especialistas e pelas entidades gestoras nacionais. Como resultado, foi proposto um conjunto de indicadores para avaliação de sistemas de logística reversa de resíduos de equipamentos elétricos e eletrônicos, o qual foi submetido à validação de especialistas por meio da técnica Delphi. O conjunto proposto após a etapa de validação é composto por cinco parâmetros que exprimem uma caracterização básica do sistema e por 31 indicadores, classificados em seis dimensões: i) abrangência, ii) representatividade, iii) parcerias, iv) coleta, v) destinação e disposição final, e vi) custos e investimentos. Por fim, foi proposto um modelo de relatório para tais sistemas, integrado ao conjunto, para fornecer os dados necessários aos indicadores. / The National Solid Waste Policy of 2010 represented a new paradigm for the management of waste electrical and electronic equipment, making manufacturers, importers, distributors and merchants accountable for the collection and proper disposal of these wastes through take-back systems. Within the national scenario, the State of São Paulo is in a pioneering position regarding the implementation of reverse logistics. At the international level, the Japanese and European cases stand out as a reference in the management of such waste. In this context, the research proposed herein has the main objective of developing a set of indicators for the evaluation of waste electrical and electronic equipment take-back systems, with the purpose of contributing to the monitoring and evaluation of such systems by environmental agencies. A bibliographic review and documentary research were carried out on models of waste electrical and electronic equipment management and take-back systems in Europe, Japan and Brazil, and on indicators and criteria for the evaluation of take-back systems of such waste. Questionnaires were then applied to identify which indicators are used for the European and Japanese systems and which are suggested by experts and national producer responsibility organizations. As a result, a set of indicators was proposed for the evaluation of waste electrical and electronic equipment take-back systems, which was submitted to the validation of specialists through the Delphi method. The set proposed after the validation step is composed of five parameters that express a basic characterization of the system and 31 indicators, classified into six dimensions: i) comprehensiveness, ii) representativeness, iii) partnerships, iv) collection, v) recycling and disposal, and vi) costs and investments. Finally, a reporting model for such systems, integrated with the set of indicators, was proposed to provide the necessary data for the indicators.
114

The State of BIM-Based Quantity Take-Off Implementation Among Commercial General Contractors

Tagg, Morgan Christian 01 November 2017 (has links)
Building Information Modeling (BIM) plays an important role in today's construction industry. Models are tools that help stakeholders communicate, visualize building geometry, perform trade coordination and clash detection among others. A less popular aspect of BIM that shows high potential is the quantity take-off (QTO) feature. Yet, its implementation among commercial general contractors (GC) has not received as much attention. The purpose of this study was to identify how the BIM QTO features were being implemented among commercial general contractors, what challenges they faced and how they worked to overcome those challenges. Through a three-step process including semi structured interviews with estimators, preconstruction, BIM and Virtual Design Construction (VDC) managers, valuable insights on the BIM QTO implementation state among general contractors were gathered and analyzed. Links between BIM QTO benefits, project design phases and delivery methods, software, training, leadership and jurisdictions were discussed. The data indicated that BIM QTO's benefits were best leveraged through early general contractor involvement, the adequate contract framework, trained BIM QTO estimators, and early and strategic communication between owners, designers and estimators. The conditions for increased efficiency were discussed along with the solutions to the common BIM-based QTO challenges.
115

對中國大陸經濟起飛、出口與國有企業改革之研究 / A Study on Economy Take-off , Export and The Reform of Public Enterprise in Mailand China

黃佩佩, Whang,Pei-Pei Unknown Date (has links)
本研究主要分為三大部份,分別針對中國大陸之經濟起飛、出口與國有企 業改革加以探討。研究結果顯示:一、依據 Tsiang S.C.之經濟起飛條件 判斷,中國大陸自1977年進入自力成長的經濟起飛階段。二、出口與經濟 成長間之關係 (一)利用出口與經濟成長間之定義關係(王春源,1983)檢 驗:出口擴張對於國民所得之貢獻率,在經改以後大幅提升且具較穩定 。 (二)利用 Feder(1982)之理論模型檢驗:中國大陸之出口部門與非出 口間之要素的社會邊際生產力存在明顯差異。至於中國大陸經濟成長來源 ,主要來自模型未考慮之其他變數與非出口部門資本的邊際生產力。 (三)依據本文之修正模型,實證結果顯示:影響中國大陸經濟成長之最主 要因素來自消費與投資。出口與經濟成長間之關係則出現「門檻效果」之 現象。三、造成國企不活之深層原因,主要是制度性因素所致,國有企業 在性質上只是「機關體」而非「企業體」。另據本文利用 Chow(1994)之 理論模型,模擬分析顯示:企業在市場經濟運行的效率,相對優於傳統計 劃經濟體制。因此,國企改革應謀求將「機關體」質變為經營目標單純化 之「企業體」,建立以市場為導向,以利潤為中心之企業制度。
116

Vision and GPS based autonomous landing of an unmanned aerial vehicle

Hermansson, Joel January 2010 (has links)
<p>A control system for autonomous landing of an unmanned aerial vehicle (UAV)with high precision has been developed. The UAV is a medium sized model he-licopter. Measurements from a GPS, a camera and a compass are fused with anextended Kalman filter for state estimation of the helicopter. Four PID-controllers,one for each control signal of the helicopter, are used for the helicopter control.During the final test flights fifteen landings were performed with an average land-ing accuracy of 35 cm.    A bias in the GPS measurements makes it impossible to land the helicopter withhigh precision using only the GPS. Therefore, a vision system using a camera anda pattern provided landing platform has been developed. The vision system givesaccurate measurement of the 6-DOF pose of the helicopter relative the platform.These measurements are used to guide the helicopter to the landing target. Inorder to use the vision system in real time, fast image processing algorithms havebeen developed. The vision system can easily match up the with the camera framerate of 30 Hz.</p> / <p>Ett kontrolsystem för att autonomt landa en modellhelikopter har utvecklats.Mätdata från en GPS, en kamera samt en kompass fusioneras med ett Extend-ed Kalman Filter för tillståndsestimering av helikoptern. Fyra PID-regulatorer,en för varje kontrolsignal på helikoptern, har används för regleringen. Under densista provflygningen gjordes tre landingar av vilken den minst lyckade slutade35 cm från målet.    På grund av en drift i GPS-mätningarna är det omöjligt att landa helikopternmed hög precision med bara en GPS. Därför har ett bildbehandlingssystem som an-vänder en kamera samt ett mönster på platformen utvecklats. Bidbehandlingssys-temet mäter positionen och orienteringen av helikoptern relativt platformen. Dessamätningar används kompensera för GPS-mätningarnas drift. Snabba bildbehan-dlingsalgoritmer har utvecklats för att kunna använda bildbehandlingssystemet irealtid. Systemet är mycket snabbare än 30 bilder per sekund vilket är kameranshastighet.</p>
117

Bounded Rationality and Exemplar Models

Persson, Magnus January 2003 (has links)
<p>Bounded rationality is the study of how human cognition with limited capacity is adapted to handle the complex information structures in the environment. This thesis argues that in order to understand the bounded rationality of decision processes, it is necessary to develop decision theories that are computational process models based upon basic cognitive and perceptual mechanisms. The main goal of this thesis is to show that models of perceptual categorization based on the storage of exemplars and retrieval of similar exemplars whenever a new object is encountered (D. L. Medin & M. M. Schaffer, 1978), can be an important contribution to theories of decision making. Study I proposed, PROBEX (PROBabilities from Exemplars), a model for inferences from generic knowledge. It is a “lazy” algorithm that presumes no pre-computed abstractions. In a computer simulation it was found to be a powerful decision strategy, and it was possible to fit the model to human data in a psychologically plausible way. Study II was a theoretical investigation that found that PROBEX was very robust in conditions where the decision maker has very little information, and that it worked well even under the worst circumstances. Study III empirically tested if humans can learn to use exemplar based or one reason decision making strategies (G. Gigerenzer, P. Todd, & the ABC Research Group, 1999) where it is appropriate in a two-alternative choice task. Experiment 1 used cue structure and presentation format as independent variables, and participants easily used one reason strategies if the decision task presented the information as normal text. The participants were only able to use exemplars if they were presented as short strings of letters. Experiment 2 failed to accelerate learning of exemplar use during the decision phase, by prior exposure to exemplars in a similar task. In conclusion, this thesis supports that there are at least two modes of decision making, which are boundedly rational if they are used in the appropriate context. Exemplar strategies may, contrary to study II, only be used late in learning, and the conditions for learning need to be investigated further.</p>
118

Bounded Rationality and Exemplar Models

Persson, Magnus January 2003 (has links)
Bounded rationality is the study of how human cognition with limited capacity is adapted to handle the complex information structures in the environment. This thesis argues that in order to understand the bounded rationality of decision processes, it is necessary to develop decision theories that are computational process models based upon basic cognitive and perceptual mechanisms. The main goal of this thesis is to show that models of perceptual categorization based on the storage of exemplars and retrieval of similar exemplars whenever a new object is encountered (D. L. Medin &amp; M. M. Schaffer, 1978), can be an important contribution to theories of decision making. Study I proposed, PROBEX (PROBabilities from Exemplars), a model for inferences from generic knowledge. It is a “lazy” algorithm that presumes no pre-computed abstractions. In a computer simulation it was found to be a powerful decision strategy, and it was possible to fit the model to human data in a psychologically plausible way. Study II was a theoretical investigation that found that PROBEX was very robust in conditions where the decision maker has very little information, and that it worked well even under the worst circumstances. Study III empirically tested if humans can learn to use exemplar based or one reason decision making strategies (G. Gigerenzer, P. Todd, &amp; the ABC Research Group, 1999) where it is appropriate in a two-alternative choice task. Experiment 1 used cue structure and presentation format as independent variables, and participants easily used one reason strategies if the decision task presented the information as normal text. The participants were only able to use exemplars if they were presented as short strings of letters. Experiment 2 failed to accelerate learning of exemplar use during the decision phase, by prior exposure to exemplars in a similar task. In conclusion, this thesis supports that there are at least two modes of decision making, which are boundedly rational if they are used in the appropriate context. Exemplar strategies may, contrary to study II, only be used late in learning, and the conditions for learning need to be investigated further.
119

Vision and GPS based autonomous landing of an unmanned aerial vehicle

Hermansson, Joel January 2010 (has links)
A control system for autonomous landing of an unmanned aerial vehicle (UAV)with high precision has been developed. The UAV is a medium sized model he-licopter. Measurements from a GPS, a camera and a compass are fused with anextended Kalman filter for state estimation of the helicopter. Four PID-controllers,one for each control signal of the helicopter, are used for the helicopter control.During the final test flights fifteen landings were performed with an average land-ing accuracy of 35 cm.    A bias in the GPS measurements makes it impossible to land the helicopter withhigh precision using only the GPS. Therefore, a vision system using a camera anda pattern provided landing platform has been developed. The vision system givesaccurate measurement of the 6-DOF pose of the helicopter relative the platform.These measurements are used to guide the helicopter to the landing target. Inorder to use the vision system in real time, fast image processing algorithms havebeen developed. The vision system can easily match up the with the camera framerate of 30 Hz. / Ett kontrolsystem för att autonomt landa en modellhelikopter har utvecklats.Mätdata från en GPS, en kamera samt en kompass fusioneras med ett Extend-ed Kalman Filter för tillståndsestimering av helikoptern. Fyra PID-regulatorer,en för varje kontrolsignal på helikoptern, har används för regleringen. Under densista provflygningen gjordes tre landingar av vilken den minst lyckade slutade35 cm från målet.    På grund av en drift i GPS-mätningarna är det omöjligt att landa helikopternmed hög precision med bara en GPS. Därför har ett bildbehandlingssystem som an-vänder en kamera samt ett mönster på platformen utvecklats. Bidbehandlingssys-temet mäter positionen och orienteringen av helikoptern relativt platformen. Dessamätningar används kompensera för GPS-mätningarnas drift. Snabba bildbehan-dlingsalgoritmer har utvecklats för att kunna använda bildbehandlingssystemet irealtid. Systemet är mycket snabbare än 30 bilder per sekund vilket är kameranshastighet.
120

Pricing Power Derivatives: Electricity Swing Options

Aydin, Nadi Serhan 01 June 2010 (has links) (PDF)
The Swing options are the natural outcomes of the increasing uncertainty in the power markets, which came along with the deregulation process triggered by the UK government&rsquo / s action in 1990 to privatize the national electricity supply industry. Since then, the ways of handling the risks in the price generation process have been explored extensively. Producer-consumers of the power market felt confident as they were naturally hedged against the price fluctuations surrounding the large consumers. Companies with high power consumption liabilities on their books demanded tailored financial products that would shelter them from the upside risks while not preventing them from benefiting the low prices. Furthermore, more effective risk management practices are strongly dependent upon the successful parameterization of the underlying stochastic processes, which is also key to the effective pricing of derivatives traded in the market. In this thesis, we refer to the electricity spot price model developed jointly by Hambly, Howison and Kluge ([13]), which incorporates jumps and still maintains the analytical tractability. We also derive the forward curve dynamics implied by the spot price model and explore the effects on the forward curve dynamics of the spikes in spot price. As the main discussion of this thesis, the Grid Approach, which is a generalization of the Trinomial Forest Method, is applied to the electricity Swing options. We investigate the effects of spikes on the per right values of the Swing options with various number of exercise rights, as well as the sensitivities of the model-implied prices to several parameters.

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