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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.
171

Automated In-Field Leaf-Level Hyperspectral Imaging of Corn Plants Using a Cartesian Robotic Platform

Ziling Chen (8810570) 21 June 2022 (has links)
Agriculture-related industry and academia have widely adopted Hyperspectral Imaging (HSI) based in-field phenotyping activities. Current HSI solutions such as airborne remote sensing platforms and handheld spectrometers have been proven effective and have become popular in various phenotyping applications. However, the quality of remote sensing systems suffers from a low signal-over-noise ratio due to the imaging distance and low resolution. Handheld leaf spectrometers are slow, labor-intensive, and only measure a small spot on the leaf, which fails to represent the canopy variation. In 2018, the Purdue ABE sensor lab developed a new handheld hyperspectral leaf imager, LeafSpec. For the first time, field phenotyping researchers were able to collect high-resolution leaf hyperspectral images without the negative impacts of ambient lighting and leaf-slope angle changes. LeafSpec has been successfully tested in field assays and showed its advantageous phenotyping quality. The goal of this study was to test the hypothesis that a robotic system could replace the human operator required to perform in-field and leaf-level HSI using LeafSpec. The system consisted of a modified version of the LeafSpec device, a machine vision system for target leaf detection, a National Instrument MyRIO as a controller and a customized cartesian robotic arm with five Degrees of Freedom (DOF). For each scan, the on-board machine vision system recognized the top leaf collar and obtained the target coordinates. The coordinates were then passed to the controller, which calculated the appropriate path and acceleration profile and drove the arm to approach the target leaf and scan the leaf with the LeafSpec device. The scanned image was then processed in real-time to calculate plant physiological features such as chlorophyll content, nitrogen content and so on. In the 2019 field test, the designed system collected data from 41 corn plants with two genotypes and three levels of nitrogen treatments with an average cycle time of 86 seconds. The nitrogen content predicted by the designed system had an R squared of 0.72 with the ground truth. The developers, therefore, concluded that the robotic gantry system was capable of replacing human operators for LeafSpec hyperspectral corn leaf imaging in the field with high quality.
172

Technika ALPS v kartézském genetickém programování / ALPS Technique in Cartesian Genetic Programming

Stanovský, Peter January 2009 (has links)
This work introduces a brief summary of softcomputing and the solutions to NP-hard problems. It especially deals with evolution algorithms and their basic types. The next part involves the study of cartesian genetic programming, which belongs to the field of evolution algorithms, used mainly in the evolution of digital circuits, symbolic regression, etc. A special chapter is devoted to the studies of new technique Age layered population structure, which deals with the problems of premature convergence, which suggests the way of how the population could be divided into subpopulations split up according to the age criteria. Thanks to the maintaining of sufficient diversity, it achieves substantially better solutions in comparison to the classical evolution algorithms. This papier includes the suggestion of two ways of incorporation of the ALPS technique into CGP. In the next part of work there were carried out tests on the classic problems, that would be solved with evolution algorithms. These tests were made with and without using ALPS technique. In the part of work "Experimental results" there was discussed a contribution of using ALPS technique in CGP against the classic CGP.
173

Evoluční návrh obvodů na úrovni tranzistorů / Evolutionary Circuit Design at the Transistor Level

Žaloudek, Luděk Unknown Date (has links)
This project deals with evolutionary design of electronic circuits with an emphasis on digital circuits. It describes the theoretical basics for the evolutionary design of circuits on computer systems, including the explanation of Genetic Programming and Evolutionary Strategies, possible design levels of electronic circuits, CMOS technology overview, also the overview of the most important evolutionary circuits design methods like development and Cartesian Genetic Programming. Next introduced is a new method of digital circuits design on the transistor level, which is based on CGP. Also a design system using this new method is introduced. Finally, the experiments performed with this system are described and evaluated.
174

Healing the Cartesian Split: Understanding and Renewing Pathos in Academic Writing

Washburn, Travis 02 July 2012 (has links) (PDF)
There have always been rogues who dared to go against the traditional "intellectual" writing style of science and academia, a style that seems bent on transcending the "merely personal." Those who take this risk are embracing the rhetorical tradition of pathos, one that goes as far back as Aristotle. Current academic trends support a genre devoid of pathos and lacking true ethos—a deviation from classic rhetoric, and one that supports the Cartesian split of mind-body dualism. Neurological studies done by Antonio Damasio and others suggest that a holistic view is a more accurate picture of how a human soul functions. Philosophy and psychology support this same perspective, proving that the opposite of logic is not emotion: the opposite of logic is illogic. By the same token, there are two types of emotion: reasonable emotion and unreasonable emotion, one good, the other bad. There are dangers when emotion is left on its own, but there are equal dangers when logic is left on its own; so it is crucial that the two be united. Changing the academic super-genre and inviting pathos back will require writers to pursue, to an extent, divergent thinking.
175

Spherically-actuated platform manipulator with passive prismatic joints

Nyzen, Ronald A. January 2002 (has links)
No description available.
176

Design and control of a three degree-of-freedom planar parallel robot

Joshi, Atul Ravindra January 2003 (has links)
No description available.
177

Development of Hybrid Optimization Techniques of Mechanical Components Employing the Cartesian Grid Finite Element Method

Muñoz Pellicer, David 15 February 2024 (has links)
Tesis por compendio / [ES] Esta tesis explora enfoques innovadores para la optimización estructural, abarcando una variedad de algoritmos de optimización comúnmente utilizados en el campo. Se centra específicamente en la optimización de forma (SO) y la optimización de topología (TO). La primera contribución de esta tesis gira en torno a garantizar y mantener un nivel deseado de precisión durante todo el proceso de TO y la solución propuesta. Al establecer confianza en los componentes sugeridos por el algoritmo de TO, nuestra atención puede centrarse en la siguiente contribución. La segunda contribución de esta tesis tiene como objetivo establecer una comunicación efectiva entre los algoritmos de TO y SO. Para lograr esto, nuestro objetivo es convertir directamente la distribución óptima de materiales propuesta por el algoritmo de TO en geometría. Posteriormente, optimizamos la geometría utilizando algoritmos de SO. Facilitar una comunicación fluida entre estos dos algoritmos presenta un desafío complejo, que abordamos proponiendo una metodología basada en aprendizaje automático. Este enfoque busca extraer un número reducido de modos geométricos que pueden servir como parametrización para la geometría, lo que permite su optimización mediante algoritmos de SO. Por último, la tercera contribución recoge algunas de las ideas previas y las lleva un paso hacia delante. La metodología propuesta tiene como objetivo derivar nuevos componentes a través de enfoques basados en el conocimiento existente en lugar de depender únicamente de procesos de TO basados en la física. Sostenemos que este conocimiento se puede obtener del histórico de diseños empleados por una determinada empresa, ya que retienen un valioso conocimiento inmaterial. Esta metodología también se basa en algoritmos de aprendizaje automático, pero también consideramos técnicas para analizar datos de alta dimensionalidad y estrategias de interpolación más adecuadas. / [CA] Aquesta tesi explora enfocaments innovadors per a l'optimització estructural, abastant una varietat d'algorismes d'optimització comunament utilitzats en el camp. Se centra específicament en l'optimització de forma (SO) i l'optimització de topologia (TO). La primera contribució d'aquesta tesi gira entorn de garantir i mantenir un nivell desitjat de precisió durant tot el procés de TO i la solució proposada. En establir confiança en els components suggerits per l'algorisme de TO, la nostra atenció pot centrar-se en la següent contribució. La segona contribució d'aquesta tesi té com a objectiu establir una comunicació efectiva entre els algorismes de TO i SO. Per a aconseguir això, el nostre objectiu és convertir directament la distribució òptima de materials proposta per l'algorisme de TO en geometria. Posteriorment, optimitzem la geometria utilitzant algorismes de SO. Facilitar una comunicació fluida entre aquests dos algorismes presenta un desafiament complex, que abordem proposant una metodologia basada en aprenentatge automàtic. Aquest enfocament busca extreure un nombre reduït de maneres geomètriques que poden servir com a parametrització per a la geometria, la qual cosa permet la seua optimització mitjançant algorismes de SO. Finalment, la tercera contribució recull algunes de les idees prèvies i les porta un pas cap endavant. La metodologia recomanada té com a objectiu derivar nous components a través d'enfocaments basats en el coneixement existent en lloc de dependre únicament de processos de TO basats en la física. Sostenim que aquest coneixement es pot obtenir de l'històric de dissenys emprats per una determinada empresa, ja que retenen un valuós coneixement immaterial. Aquesta metodologia també es basa en algorismes d'aprenentatge automàtic, però també considerem tècniques per a analitzar dades d'alta dimensionalitat i estratègies d'interpolació més adequades. / [EN] This thesis explores innovative approaches for structural optimization, encompassing a variety of commonly used optimization algorithms in this field. It specifically focuses on shape optimization (SO) and topology optimization (TO). The first contribution of this research revolves around ensuring and maintaining a desired level of accuracy throughout the TO process and the proposed solution. By establishing confidence in the suggested components of the TO algorithm, our attention can then shift to the subsequent contribution. The second contribution of this thesis aims to establish effective communication between TO and SO algorithms. To achieve this, our goal is to directly convert the optimal material distribution proposed by the TO algorithm into geometry. Subsequently, we optimize the geometry using SO algorithms. Facilitating seamless communication between these two algorithms presents a non-trivial challenge, which we address by proposing a machine learning-based methodology. This approach seeks to extract a reduced number of geometric modes that can serve as a parameterization for the geometry, enabling further optimization by SO algorithms. Lastly, the third contribution builds upon the previous idea, taking it a step forward. The proposed methodology aims to derive new components through knowledge-based approaches instead of relying solely on physics-based TO processes. We argue that this knowledge can be acquired from the historical designs employed by a given company as they retain invaluable immaterial know-how. This methodology also relies on machine learning algorithms, but we also consider techniques for analyzing high-dimensional data and more suitable interpolation strategies. / The authors gratefully acknowledge the financial support of Conselleria d’Educació, Investigació, Cultura i Esport, Generalitat Valenciana, project Prometeo/2016/007, Prometeo/2021/046 and CIAICO/2021/226. Ministerio de Economía, Industria y Competitividad project DPI2017-89816-R and Ministerio de Educación FPU16/07121. / Muñoz Pellicer, D. (2024). Development of Hybrid Optimization Techniques of Mechanical Components Employing the Cartesian Grid Finite Element Method [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/202661 / Compendio
178

Kemiämnets normer och värden : Diskursanalytiska studier av nationella prov i kemi och tillhörande elevtexter

Ståhl, Marie January 2016 (has links)
The aim of this thesis was to examine the conditions for democratic bildung-oriented education for students in the school science discourse. This is something that the Swedish curriculum is based on and thereby the education should develop students' capacity for social, political and cultural awareness. The theoretical framework used is grounded in critical didactics and feminist theories which assume that students should feel involved and get their voices heard. The Swedish national test in chemistry (2009-2012) and student answers (198n) from one of the items in the 2009 test have been analyzed using discourse analysis. The first study explored the norms and values present in the national tests in chemistry, in relation to people, society and nature. The second study focused on student’s evaluative language in their free-text answers to one of the items. Thereby attitudes in student answers were projected in relation to the norms and values found in the first study. Finally, the student answers were used once more in a third study, where students’ positioning in relation to the scientific discourse in the chemistry test (2009) was explored, as well as which feminist figurations these subject positions express. The results show that the national tests harbor an elitist image and anandrocentric bias.The normative message is that students should adopt an objective, rational, non-judgmental and non-emotional role. Topics connected to young people’s everyday life, that might interest students, are rare. Contrary to the normative messages mediated by the tests, students use evaluative and embodied language to a high extent in their answers. They choose to write about topics that are close to their everyday life and they show that they are emotionally engaged. Through feminist figurations theories used in the third study one can see how the student-subject positions offer resistance in different ways. This is shown in their criticism of science and technology, human society and nature. The students' responses have embraced an embodied chemistry that can be interpreted as teaching based on bildung and deliberative discussions.
179

Variational modelling of cavitation and fracture in nonlinear elasticity

Henao Manrique, Duvan Alberto January 2009 (has links)
Motivated by experiments on titanium alloys of Petrinic et al. (2006), which show the formation of cracks through the growth and coalescence of voids in ductile fracture, we consider the problem of formulating a variational model in nonlinear elasticity compatible both with cavitation and the appearance of discontinuities across two-dimensional surfaces. As in the model for cavitation of Müller and Spector (1995) we address this problem, which is connected to the sequential weak continuity of the determinant of the deformation gradient in spaces of functions having low regularity, by means of adding an appropriate surface energy term to the elastic energy. Based upon considerations of invertibility, we derive an expression for the surface energy that admits a physical and a geometrical interpretation, and that allows for the formulation of a model with better analytical properties. We obtain, in particular, important regularity results for the inverses of deformations, as well as the weak continuity of the determinants and the existence of minimizers. We show, further, that the creation of surface can be modeled by carefully analyzing the jump set of the inverses, and we point out some connections between the analysis of cavitation and fracture, the theory of SBV functions, and the theory of Cartesian currents of Giaquinta, Modica, and Soucek. In addition to the above, we extend previous work of Sivaloganathan, Spector and Tilakraj (2006) on the approximation of minimizers for the problem of cavitation with a constraint in the number of flaw points, and present some numerical results for this problem.
180

Explorando equações cartesianas e paramétricas em um ambiente informático

Silva, Carlos Roberto da 16 October 2006 (has links)
Made available in DSpace on 2016-04-27T16:57:45Z (GMT). No. of bitstreams: 1 EDM - Carlos Roberto da Silva.pdf: 4174831 bytes, checksum: 1d38259ebfb2955961be336c2a3a1d23 (MD5) Previous issue date: 2006-10-16 / Secretaria da Educação do Estado de São Paulo / This research has as objective verify if in a computer science environment allows to the student to recognize some curves properties through representations and graphical interpretations in dynamic way with the use of parameters for one comprehension better of its equations. We verified that the articulating between the points of view cartesian and parametric and the conversions among some registers of semiotic representation it makes the student think about the correlation that exists between some properties geometric of the plane curves and its cartesian or parametric equations. For this research we elaborate a didactic sequence based on some topics of the Didactic Engineering and we apply during five sessions in a group of 10 students taking the third year of high school. We verified that the graphic constructions of some plane curves varying the real values of its parameters in its equations for the development of an GIF (Graphic Information Format), they allow the students to observe the geometric effect caused by this variation what it favors the understanding of the parameter notion in analytical geometry / Esta dissertação tem por objetivo verificar se um ambiente informático permite ao aluno reconhecer algumas propriedades de curvas, por meio de representações e interpretações gráficas de maneira dinâmica, com o uso de parâmetros, para uma melhor compreensão de suas equações. Identificamos que a articulação entre os pontos de vista cartesiano e paramétrico e as conversões entre alguns registros de representação semiótica possibilitam ao aluno refletir sobre a correlação entre algumas propriedades geométricas de curvas planas e suas equações cartesianas ou paramétricas. Para esta pesquisa, elaboramos uma seqüência didática com base em alguns elementos de uma Engenharia Didática e aplicamos durante cinco sessões a um grupo de 10 alunos da 3ª série do Ensino Médio. Verificamos que as construções gráficas de algumas curvas planas, variando os valores reais de parâmetros em suas equações, para o desenvolvimento de um GIF animado, permitem ao aluno observarem os efeitos geométricos provocados pela sua variação, favorecendo o entendimento da noção de parâmetro na geometria analítica

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