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1
Knobloch, Josef. "Mapování geometrických chyb v pracovním prostoru obráběcího stroje." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229906.
Повний текст джерелаАнотація:
Diploma thesis offers a new approach to the measuring of geometry errors in the machine tool workspace with the aid of laser tracker. There is a method of data acquisition and also the Matlab programs for data processing suggested in the thesis. This method can determine the accuracy and repeatibility of positioning and angular displacement of the numerical controlled axes of the measured machine tool and it compiles its mathematical model. All the gathered knowledge is used to evaluation of geometric accuracy of the virtual machined workpiece.
2
Fyn-Sydney, Betty Iboroma. "Phan geometries and error correcting codes." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4433/.
Повний текст джерелаАнотація:
In this thesis, we define codes based on the Phan geometry of type An. We show that the action of the group SUn+1(q) is not irreducible on the code. In the rank two case, we prove that the code is spanned by those apartments which only consist of chambers belonging to the Phan geometry and obtain submodules for the code.
3
Suchomel, Kamil. "Vlivy výrobních technologií na geometrickou a rozměrovou přesnost obrobků." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-319263.
Повний текст джерелаАнотація:
The aim of the diploma thesis is to describe influences of selected production technologies on geometrical and dimensional accuracy of workpieces. Specific technologies - turning, milling and grinding and the machines on which these technologies will be implemented - a vertical lathe, a portal milling machine and a center grinder are described in this thesis. Additionally a procedure is created for adding geometric errors to a tri-axial machine tool to describe the entire working area of the machine in terms of errors. Subsequently an analysis of each geometric error is created for each machine and their influence on the resulting workpiece is determined.
4
Mårtensson, Jonas. "Geometric analysis of stochastic model errors in system identification." Doctoral thesis, KTH, Reglerteknik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4506.
Повний текст джерелаАнотація:
Models of dynamical systems are important in many disciplines of science, ranging from physics and traditional mechanical and electrical engineering to life sciences, computer science and economics. Engineers, for example, use models for development, analysis and control of complex technical systems. Dynamical models can be derived from physical insights, for example some known laws of nature, (which are models themselves), or, as considered here, by fitting unknown model parameters to measurements from an experiment. The latter approach is what we call system identification. A model is always (at best) an approximation of the true system, and for a model to be useful, we need some characterization of how large the model error is. In this thesis we consider model errors originating from stochastic (random) disturbances that the system was subject to during the experiment. Stochastic model errors, known as variance-errors, are usually analyzed under the assumption of an infinite number of data. In this context the variance-error can be expressed as a (complicated) function of the spectra (and cross-spectra) of the disturbances and the excitation signals, a description of the true system, and the model structure (i.e., the parametrization of the model). The primary contribution of this thesis is an alternative geometric interpretation of this expression. This geometric approach consists in viewing the asymptotic variance as an orthogonal projection on a vector space that to a large extent is defined from the model structure. This approach is useful in several ways. Primarily, it facilitates structural analysis of how, for example, model structure and model order, and possible feedback mechanisms, affect the variance-error. Moreover, simple upper bounds on the variance-error can be obtained, which are independent of the employed model structure. The accuracy of estimated poles and zeros of linear time-invariant systems can also be analyzed using results closely related to the approach described above. One fundamental conclusion is that the accuracy of estimates of unstable poles and zeros is little affected by the model order, while the accuracy deteriorates fast with the model order for stable poles and zeros. The geometric approach has also shown potential in input design, which treats how the excitation signal (input signal) should be chosen to yield informative experiments. For example, we show cases when the input signal can be chosen so that the variance-error does not depend on the model order or the model structure. Perhaps the most important contribution of this thesis, and of the geometric approach, is the analysis method as such. Hopefully the methodology presented in this work will be useful in future research on the accuracy of identified models; in particular non-linear models and models with multiple inputs and outputs, for which there are relatively few results at present.QC 20100810
5
Mårtensson, Jonas. "Geometric analysis of stochastic model errors in system identification /." Stockholm : Elektro- och systemteknik, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4506.
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Melo, Nolmar. "Codigos geometricos de Goppa via metodos elementares." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306316.
Повний текст джерелаАнотація:
Orientadores: Paulo Roberto Brumatti, Fernando Eduardo Torres OrihuelaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica
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Resumo: O objetivo central desta dissertação foi o de apresentar os Códigos Geométricos de Goppa via métodos elementares que foram introduzidos por J. H. van Lint, R. Pellikaan e T. Hfhold por volta de 1998. Numa primeira parte da dissertação são apresentados os conceitos fundamentais sobre corpos de funções racionais de uma curva algébrica na direção de se definir os códigos de Goppa de maneira clássica, neste estudo nos baseamos principalmente no livro ¿Algebraic Function Fields and Codes¿ de H. Stichtenoth. A segunda parte inicia-se com a introdução dos conceitos de funções peso, grau e ordem que são fundamentais para o estudo dos Códigos de Goppa via métodos elementares de álgebra linear e de semigrupos, tal estudo foi baseado em ¿Algebraic geometry codes¿ de J. H. van Lint, R. Pellikaan e T. Hfhold.A dissertação termina com a apresentação de exemplos que ilustram os métodos elementares que nos referimos acima
Abstract: The central objective of this dissertation was to present the Goppa Geometry Codes via elementary methods which were introduced by J. H. van Lint, R. Pellikaan and T. Hfhold about 1998. On the first past of such dissertation are presented the fundamental concepts about fields of rational functions of an algebraic curve in the direction as to define the Goppa Codes on a classical manner. In this study we based ourselves mainly on the book ¿Algebraic Function Fields and Codes¿ of H. Stichtenoth. The second part is initiated with an introduction about the functions weight, degree and order which are fundamental for the study of the Goppa Codes throught elementary methods of linear algebra and of semigroups and such study was based on ¿Algebraic Geometry Codes¿ of J. h. van Lint, R. Pellikaan and T. Hfhold. The dissertation ends up with a presentation of examples which illustrate the elementary methods that we have referred to above
Mestrado
Algebra
Mestre em Matemática
7
Bhatia, Shaleen. "Effect of Machine Positional Errors on Geometric Tolerances in Additive Manufacturing." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406820498.
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8
Bibler, Jared Evan. "Effects of imbalance and geometric error on precision grinding machines." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43428.
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Slavíček, Josef. "Měření vřeten obráběcích strojů pomocí bezkontaktních snímačů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230490.
Повний текст джерелаАнотація:
The goal of this work is to propose a suitable methodology for measuring and evaluating the geometric precision of spindle rotation. Identification and classification of errors while moving spindle. Part of this work should be also a program in LabVIEW that evaluate the errors in the motion of the spindle. Practical functionality of the proposed measurement system should be tested at selected MCV754 QUICK machines, lathes SV 18 and milling machine FNG 32. For processing of the results should be used basic statistical procedures. This thesis includes research in the field of machine tool spindles and different ways of measuring spindle motion deviations from the ideal path. There is also included the effect of sensors to measuring spindle running accuracy and identification of suitable sensors applicable for this application. There is a proposal of measurement of selected machinery, and defines all the components required for measurements that were used during spindle running precision measurement. Part of this work is a basic description of the program developed for evaluating errors in the motion of the spindle.
10
Ramanaiah, Harikishan Veluru. "Relation between Process Capability Indices and Geometric Errors of Machine Tool." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215977.
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11
Jiang, Xiaogeng. "Characterising geometric errors in rotary axes of 5-axis machine tools." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5871/.
Повний текст джерелаАнотація:
It is critical to ensure that a 5-axis machine tool is operating within its geometric tolerance. However, there are various sources of errors influencing its accuracy; testing them with current methods requires expensive equipment and long machine down time. This motivates the development of a simple and fast way to identify and characterise geometric errors of 5-axis machine tools. A method using a Double Ball Bar (DBB) is proposed to characterise rotary axes Position Independent Geometric Errors (PIGEs), which are caused by imperfections during assembly of machine components. An established method is used to test the same PIGEs, and the results are used to validate the developed method. The Homogeneous Transformation Matrices (HTMs) are used to build up a machine tool model and generate DBB error plots due to different PIGEs based on the given testing scheme. The simulated DBB trace patterns can be used to evaluate individual error impacts for known faults and diagnose machine tool conditions. The main contribution is the development of the fast and simple characterisation of the PIGEs of rotary axes. The results show the effectiveness and improved efficiency of the new methods, which can be considered for 5-axis machine tool maintenance and checking.
12
Alzubi, Jafar A. "Forward error correction coding and iterative decoding using algebraic geometric theory." Thesis, Swansea University, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.582101.
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Bhadauria, Rashmi. "Geometric error evaluation of pressure and suction sides of airfoil sections." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/39819.
Повний текст джерелаАнотація:
This thesis presents geometric computing algorithms for the evaluation of geometric errors on the pressure and suction sides of an airfoil section. Airfoil blades such as those in an impeller have a complex freeform geometry which poses significant challenges to the geometric error evaluation tasks. Reliable error evaluation is critical to the impellers as wrongful rejections will lead to significant financial losses. In practice, touch-probe coordinate measuring machines are employed to acquire measurement data points on the impeller blade surface along pre-specified sections. The measurement data points are then used to evaluate against the specified geometric tolerances including the profile tolerance and airfoil thickness control.
Profile tolerances can be defined in three ways: bilateral asymmetric, bilateral symmetric, and unilateral. Existing methods for profile error evaluation are not capable of evaluating all three possible types of profile tolerance. These methods are not adaptive with respect to the specified tolerance zone boundaries. This thesis proposes a novel Scaled Minimax Method which is able to address all types of profile tolerance. The proposed method builds on the conventional Minimax Method and utilizes a scaling constant to control the relative positioning of the evaluated profile error zone boundaries. Thickness control is a less-known tolerance specification for airfoil sections. It controls the overall shape deviation of an airfoil section between the pressure and suction sides. The proposed evaluation method is based on determining a minimum error zone via simultaneously shrinking the outer boundary and growing the inner boundary for the involved measurement data points. Numerous case studies have been performed to validate the effectiveness of the proposed geometric error evaluation methods.
14
Breuel, Thomas M. "Geometric Aspects of Visual Object Recognition." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/7342.
Повний текст джерелаАнотація:
This thesis presents there important results in visual object recognition based on shape. (1) A new algorithm (RAST; Recognition by Adaptive Sudivisions of Tranformation space) is presented that has lower average-case complexity than any known recognition algorithm. (2) It is shown, both theoretically and empirically, that representing 3D objects as collections of 2D views (the "View-Based Approximation") is feasible and affects the reliability of 3D recognition systems no more than other commonly made approximations. (3) The problem of recognition in cluttered scenes is considered from a Bayesian perspective; the commonly-used "bounded-error errorsmeasure" is demonstrated to correspond to an independence assumption. It is shown that by modeling the statistical properties of real-scenes better, objects can be recognized more reliably.
15
Fredriksson, Albin. "Robust optimization of radiation therapy accounting for geometric uncertainty." Doctoral thesis, KTH, Optimeringslära och systemteori, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122262.
Повний текст джерелаАнотація:
Geometric errors may compromise the quality of radiation therapy treatments. Optimization methods that account for errors can reduce their effects. The first paper of this thesis introduces minimax optimization to account for systematic range and setup errors in intensity-modulated proton therapy. The minimax method optimizes the worst case outcome of the errors within a given set. It is applied to three patient cases and shown to yield improved target coverage robustness and healthy structure sparing compared to conventional methods using margins, uniform beam doses, and density override. Information about the uncertainties enables the optimization to counterbalance the effects of errors. In the second paper, random setup errors of uncertain distribution---in addition to the systematic range and setup errors---are considered in a framework that enables scaling between expected value and minimax optimization. Experiments on a phantom show that the best and mean case tradeoffs between target coverage and critical structure sparing are similar between the methods of the framework, but that the worst case tradeoff improves with conservativeness. Minimax optimization only considers the worst case errors. When the planning criteria cannot be fulfilled for all errors, this may have an adverse effect on the plan quality. The third paper introduces a method for such cases that modifies the set of considered errors to maximize the probability of satisfying the planning criteria. For two cases treated with intensity-modulated photon and proton therapy, the method increased the number of satisfied criteria substantially. Grasping for a little less sometimes yields better plans. In the fourth paper, the theory for multicriteria optimization is extended to incorporate minimax optimization. Minimax optimization is shown to better exploit spatial information than objective-wise worst case optimization, which has previously been used for robust multicriteria optimization. The fifth and sixth papers introduce methods for improving treatment plans: one for deliverable Pareto surface navigation, which improves upon the Pareto set representations of previous methods; and one that minimizes healthy structure doses while constraining the doses of all structures not to deteriorate compared to a reference plan, thereby improving upon plans that have been reached with too weak planning goals.QC 20130516
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Gruppi, Maurício Gouveia. "Methods for avoiding round-off errors on 2D and 3D geometric simplification." Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/9401.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Neste trabalho avaliou-se a ocorrência de erros de arredondamento decorrentes do uso de aritmética de ponto-flutuante em algoritmos de simplificação geométrica 2D e 3D. Erros de arredondamento podem fazer com que algoritmos produzam resultados topologicamente inconsistentes, isto ́e, resultados que violam alguma característica crucial do modelo original. Foram mostradas situações em que inconsistências ocorrem, mesmo em algoritmos projetados para evitá-las. Visando contornar este problema, dois métodos foram propostos: EPLSimp, para simplificação de linhas, e UGSimp para simplificação de malhas triangulares. Em ambos os métodos, testes preemptivos para verificação de inconsistência topológica foram realizados utilizando-se núumeros racionais de precisão múltipla, em vez de números de ponto-flutuante. O uso de números racionais não gera erros de arredondamento, entretanto o uso de precisão múltipla implica em um aumento no tempo de execução dos algoritmos. Para compensar esta redução de desempenho, os algoritmos foram implementados com o paradigma de computação paralela. Como resultado, temos dois métodos de simplificação isentos de erros de arredondamento por ponto- flutuante. Testes mostraram um ganho considerável no tempo de execução com as implementações paralelas.
In this work, we evaluated the occurrence of round-off errors on floating-point arith- metic for the problem of 2D and 3D geometric simplification. Round-off errors may lead algorithms to produce topologically inconsistent results, that is, results that fail to preserve crucial features of the original model. Some algorithms are designed to avoid such inconsistencies, however, they are usually implemented with floating- point arithmetic. Even these algorithms may fail to output topologically consistent results due to round-off errors. In order to overcome this issue, two methods were proposed: EPLSimp for polyline simplification, and UGSimp, for triangular mesh simplification. On both methods, preemptive tests are carried out to detect and pre- vent topological inconsistencies. Such tests use multiple precision rational numbers instead of floating-point numbers. The use of rational numbers does not present round-off errors. Nevertheless, it causes an increase on the execution time of the algorithms. To compensate for this performance loss, both algorithms were imple- mented using a parallel computing paradigm. As result, the methods presented do not output topologically inconsistent models. Tests have shown a considerable performance gain with parallel implementations of the proposed approaches.
17
Jain, Aashish. "Error Visualization in Comparison of B-Spline Surfaces." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/35319.
Повний текст джерелаАнотація:
Geometric trimming of surfaces results in a new mathematical description of the matching surface. This matching surface is required to closely resemble the remaining portion of the original surface. Typically, the approximation error in such cases is measured with a view to minimize it. The data associated with the error between two matching surfaces is large and needs to be filtered into meaningful information.This research looks at suitable norms for achieving this data reduction or abstraction with a view to provide quantitative feedback about the approximation error. Also, the differences between geometric shapes are easily discerned by the human eye but are difficult to characterize or describe. Error visualization tools have been developed to provide effective visual inputs that the designer can interpret into meaningful information.Master of Science
18
Fletcher, Simon. "Computer aided system for intelligent implementation of machine tool error reduction methodologies." Thesis, University of Huddersfield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368312.
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Laspas, Theodoros. "Modeling and measurement of geometric error of machine tools : Methodology and implementation." Thesis, KTH, Industriell produktion, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-157641.
Повний текст джерелаАнотація:
One of the main performance criteria for a machine tool is its ability to manufacture dimensionally and geometrically accurate parts. In this context evaluation of the geometric and kinematic accuracy of machine tools is important for achieving a high accuracy of machine parts. Moreover, the potential of predicting the accuracy of the machine tool outcome would benefit by reducing the non-value adding operations of machined parts measurement. The aim of this thesis is to develop a methodology for modeling geometric errors of machine tools in order to evaluate the geometric and kinematic accuracy and estimate the machined part accuracy by predicting the error motion of the machine tool for a given toolpath. The thesis consists of the description of the methodology that includes and explains aspects necessary for the development of the machine geometric error model. Additionally, a laser interferometer measurement process of the geometric errors and the various parameters necessary for the model development is presented. A three axis machine tool is utilized in order to investigate and analyze the model and to measure the geometric errors. An analysis is made for evaluating the accuracy of the machine tool. Finally, a computational implementation of the model is made and two simple toolpaths are generated in order to demonstrate the potential of the model in predicting the geometric errors of the machine.En av de viktigaste prestationskriterierna för en verktygsmaskin är dess förmåga att tillverka dimensionellt och geometriskt korrekta delarna. I detta sammanhang är utvärderingen av den geometriska och kinematiska noggrannhet av maskinverktyg är viktigt för att uppnå en hög noggrannhet av maskindelar. Dessutom skulle möjligheten att förutsäga noggrannheten av verktygsmaskiner resultatet gynnas genom att minska icke värdeskapande verksamhet bearbetade delar mätning. Syftet med denna avhandling är att utveckla en metod för att modellera geometriska fel av verktygsmaskiner för att utvärdera den geometriska och kinematiska noggrannhet och uppskatta den bearbetade komponentens noggrannheten genom att förutsäga felet verktygmaskinens rörelse för en given verktygsbana. Avhandlingen beskriver en metod som omfattar och förklarar de aspekter som är nödvändiga för utveckling av en geometrisk felmodell för verktygsmaskiner. Dessutom presenteras en mätprocess som, använder laserinterferometer, för identifiering av de geometriska fel och parametrar som är nödvändiga för att utveckla modellen. En tre-axlig verktygsmaskin används för att undersöka och analysera modellen samt för att mäta dess geometriska fel. En analys görs för att utvärdera verktygsmaskinens noggranhet. Slutligen är denna felmodell beräknad och två enkla verktygsbanor används i syfte att visa modellens potential att förutsäga geometriska fel i maskinen.
20
Di, Giacomo Benedito. "Computer aided calibration and hybrid compensation of geometric errors in coordinate measuring machines." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306885.
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21
Khameneifar, Farbod. "Section-specific geometric error evaluation of airfoil blades based on digitized surface data." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55847.
Повний текст джерелаАнотація:
Manufactured aero-engine blades are normally inspected in sections. Given discrete section-specific data points, the related geometric error evaluation task for three-dimensional tolerances of the blades is challenging and not yet well studied by researchers. Particularly, the existing method shows limited effectiveness in detecting position error and difficulty in accurate estimation of orientation error of airfoil sections. Moreover, touch-probes on a coordinate measuring machine are traditionally used to collect sectional coordinate data, which is a lengthy process as the data is collected through probe contact with the blade surface. Blade manufacturers would rather use 3D laser scanning that can complete data acquisition much faster. However, this poses a new challenge to data analysis. The collected set of points, referred to as point cloud, is all over the surface rather than at the desired, pre-specified sections. Thus, generating reliable section-specific data from the massive, unorganized scanned data points remains a problem to be solved. This thesis first presents a new methodology for evaluating three-dimensional tolerances of airfoil sections based on reconstructing the airfoil profiles from section-specific data points. According to a given measurement uncertainty, a progressive curve fitting scheme is proposed to generate the airfoil profile that meets the uncertainty constraint. Subsequently, the profile is utilized in related feature extraction of the proposed error evaluation approach. The second part of the thesis focuses on generating the reliable section-specific data points from the complete surface scan. An adaptive surface projection of data points onto the pre-specified section plane is proposed. A localized surface-fitting scheme is devised for this purpose. The main challenge lies in the selection of local data points, referred to as local neighborhood, for surface fitting. In particular, with the non-uniform distribution of data points in a noisy point cloud, existing neighborhood selection methods lead to biased fitting results. To avoid bias, a method of establishing balanced local neighborhood for surface fitting is proposed. An automated technique is also presented for systematic identification of eligible points for projection. The proposed computational framework in this thesis enables fully automatic and accurate evaluation of geometric errors using the latest high-speed geometric inspection platform.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
22
Dai, Xiaogang. "Score Test and Likelihood Ratio Test for Zero-Inflated Binomial Distribution and Geometric Distribution." TopSCHOLAR®, 2018. https://digitalcommons.wku.edu/theses/2447.
Повний текст джерелаАнотація:
The main purpose of this thesis is to compare the performance of the score test and the likelihood ratio test by computing type I errors and type II errors when the tests are applied to the geometric distribution and inflated binomial distribution. We first derive test statistics of the score test and the likelihood ratio test for both distributions. We then use the software package R to perform a simulation to study the behavior of the two tests. We derive the R codes to calculate the two types of error for each distribution. We create lots of samples to approximate the likelihood of type I error and type II error by changing the values of parameters.
In the first chapter, we discuss the motivation behind the work presented in this thesis. Also, we introduce the definitions used throughout the paper. In the second chapter, we derive test statistics for the likelihood ratio test and the score test for the geometric distribution. For the score test, we consider the score test using both the observed information matrix and the expected information matrix, and obtain the score test statistic zO and zI .
Chapter 3 discusses the likelihood ratio test and the score test for the inflated binomial distribution. The main parameter of interest is w, so p is a nuisance parameter in this case. We derive the likelihood ratio test statistics and the score test statistics to test w. In both tests, the nuisance parameter p is estimated using maximum likelihood estimator pˆ. We also consider the score test using both the observed and the expected information matrices.
Chapter 4 focuses on the score test in the inflated binomial distribution. We generate data to follow the zero inflated binomial distribution by using the package R. We plot the graph of the ratio of the two score test statistics for the sample data, zI /zO , in terms of different values of n0, the number of zero values in the sample.
In chapter 5, we discuss and compare the use of the score test using two types of information matrices. We perform a simulation study to estimate the two types of errors when applying the test to the geometric distribution and the inflated binomial distribution. We plot the percentage of the two errors by fixing different parameters, such as the probability p and the number of trials m.
Finally, we conclude by briefly summarizing the results in chapter 6.
23
Mazza, Francesco. "Valutazione sperimentale del campo aerodinamico prodotto da rasaerba industriali: correlazione tra parametri geometrici delle lame." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7329/.
Повний текст джерелаАнотація:
Il presente elaborato tratta dell’analisi dell’incertezza caratterizzante le misure sperimentali per la portata in massa del flusso d’aria generato dalla rotazione di una generica lama da rasaerba, eseguite attraverso l’impiego di un’apposita strumentazione sperimentale.
Una campagna di sperimentazione è stata avviata dal Laboratorio di Aerodinamica sperimentale dell’Università di Bologna, in collaborazione con l’azienda Global Garden Products, dedicata alla valutazione delle prestazioni aerodinamiche, in termini di portata d’aria elaborata, di lame da rasaerba.
Un’apposita apparecchiatura sperimentale è stata messa a punto, progettata per permettere il calcolo della portata in massa d’aria, elaborata da una generica lama, a partire dall’acquisizione di misure di pressione. Un’analisi dimensionale è stata applicata al modello teorico, finalizzata alla definizione di un coefficiente adimensionale di portata.
Parallelamente alla definizione del metodo di sperimentazione si è proceduto alla caratterizzazione metrologica dello stesso, in termini di precisione, giustezza e accuratezza delle misure ottenibili. Nell’ambito dell’analisi dell’incertezza di misura metodologica è stata effettuata, in primo luogo, una caratterizzazione delle misure realizzate dal trasduttore di pressione impiegato nella sperimentazione. Successivamente il risultato ottenuto è stato impiegato nella definizione, a differenti livelli di ripetizione, dell’incertezza di misura, propria del metodo di sperimentazione impiegato per misurare la portata elaborata da una generica lama.
L’esame dei risultati sperimentali ottenuti rivela come la strumentazione impiegata sia adeguata al compito per assolvere il quale essa è stata sviluppata.
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Everitt, Niklas. "Identification of Modules in Acyclic Dynamic Networks A Geometric Analysis of Stochastic Model Errors." Licentiate thesis, KTH, Reglerteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159698.
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Li, Ding. "ESA ExoMars Rover PanCam System Geometric Modeling and Evaluation." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1420788556.
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Wang, Daodang, Zhidong Gong, Ping Xu, Rongguang Liang, Ming Kong, Jun Zhao, Chao Wang, Linhai Mo, and Shuhui Mo. "Geometrical error calibration in reflective surface testing based on reverse Hartmann test." SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/627168.
Повний текст джерелаАнотація:
In the fringe-illumination deflectometry based on reverse-Hartmann-test configuration, ray tracing of the modeled testing system is performed to reconstruct the test surface error. Careful calibration of system geometry is required to achieve high testing accuracy. To realize the high-precision surface testing with reverse Hartmann test, a computer-aided geometrical error calibration method is proposed. The aberrations corresponding to various geometrical errors are studied. With the aberration weights for various geometrical errors, the computer-aided optimization of system geometry with iterative ray tracing is carried out to calibration the geometrical error, and the accuracy in the order of sub-nanometer is achieved.
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Bringmann, Bernhard. "Improving geometric calibration methods for multi-axis machining centers by examining error interdependencies effects /." Düsseldorf : VDI-Verl, 2007. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=015962642&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Hong, Cefu. "Error Calibration on Five-axis Machine Tools by Relative Displacement Measurement between Spindle and Work Table." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/157572.
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Acharya, Srikanth B. "A multivariate statistical analysis on sampling uncertainties of geometric and dimensional errors for circular features /." Cincinnati, Ohio University of Cincinnati, 2005. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1113427839.
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Flynn, Joseph. "The identification of geometric errors in five-axis machine tools using the telescoping magnetic ballbar." Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.698982.
Повний текст джерелаАнотація:
To maximise productivity and reduce scrap in high-value, low-volume production, five-axis machine tool (5A-MT) motion accuracy must be verified quickly and reliably. Numerous metrology instruments have been developed to measure errors arising from geometric imperfections within and between machine tool axes (amongst other sources). One example is the TMBB, which is becoming an increasingly popular instrument to measure both linear and rotary axis errors. This research proposes new TMBB measurement technique to rapidly, accurately and reliably measure all position-independent rotary axis errors in a 5A-MT. In this research two literature reviews have been conducted. The findings informed the subsequent development of a virtual machine tool (VMT). This VMT was used to capture the effects of rotary and linear axis position-independent geometric errors, and apparatus set-up errors on a variety of candidate measurement routines. This new knowledge then informed the design of an experimental methodology to capture specific phenomena that were observed within the VMT on a commercial 5A-MT. Finally, statistical analysis of experimental measurements facilitated a quantification of the repeatability, strengths and limitations of the final testing method concept. The major contribution of this research is the development of a single set-up testing procedure to identify all 5A-MT rotary axis location errors, whilst remaining robust in the presence of set-up and linear axis location errors. Additionally, a novel variance-based sensitivity analysis approach was used to design testing procedures. By considering the effects of extraneous error sources (set-up and linear location) in the design and validation phases, an added robustness was introduced. Furthermore, this research marks the first usage of Monte Carlo uncertainty analysis in conjunction with rotary axis TMBB testing. Experimental evidence has shown that the proposed corrections for set-up and linear axis errors are highly effective and completely indispensable in rotary axis testing of this kind. However, further development of the single set-up method is necessary, as geometric errors cannot always be measured identically at different testing locations. This has highlighted the importance of considering the influences on 5A-MT component errors on testing results, as the machine tool axes cannot necessarily be modelled as straight lines.
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Carvalho, Breno Elias Bretas de. "Estimação de estado em sistemas elétricos de potência: a interpretação geométrica aplicada ao processamento de erros de medidas, de parâmetros e de topologia." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-05122018-082539/.
Повний текст джерелаАнотація:
Este trabalho foi proposto com o objetivo de implementar uma ferramenta computacional para estimar os estados (tensões complexas nodais) de um sistema elétrico de potência e aplicar métodos alternativos para o processamento de erros topológicos, erros de parâmetros e/ou de erros grosseiros em medidas, baseados na interpretação geométrica dos erros e no conceito de inovação das medidas. O método utilizado para a resolução do problema de estimação de estado é o de mínimos quadrados ponderados. Através da interpretação geométrica, demonstrou-se matematicamente que o erro da medida é constituído de uma componente detectável e uma não-detectável, entretanto, as metodologias até então utilizadas para o processamento de erros consideram apenas a componente detectável do erro e, como consequência, podem falhar. Na tentativa de contornar essa limitação e baseado nos conceitos citados previamente, foi estudada e implementada uma metodologia alternativa para processar tais erros baseada na análise das componentes dos erros das medidas. Em primeiro lugar, é testado se o conjunto de medidas possui erros utilizando, para isso, o valor do erro de medida composto normalizado. Em seguida, diferencia-se se um ou outro erro ocorreu, ou mesmo se mais de um tipo de erro ocorreu. A correção a ser feita no parâmetro de linha ou na medida com erro grosseiro será o erro normalizado composto correspondente. A abordagem proposta neste trabalho requer somente um conjunto de medidas, e no mesmo instante. Para validação do programa, foram feitas diversas simulações nos sistemas de 14 e 57 barras do IEEE.This work was proposed with the objective to implement a computational tool to estimate the states (nodal complex voltages) of a power system and apply alternative methods for the processing of topological errors, parameter errors and/or gross errors in measurements, based on the geometric interpretation of the errors and the innovation concept of measurements. The method used to solve the state estimation problem is the weighted least squares. Through geometric interpretation, it has been demonstrated mathematically that the measurement error is composed by a detectable component and a non-detectable, however, the methodologies heretofore used for error processing consider only the detectable component of the error and, consequently, can fail. In an attempt to overcome this limitation and based on the concepts mentioned previously, an alternative approach to process such errors was studied and implemented based on the analysis of the components of the measurements errors. Firstly, it is tested if the set of measurements has errors using, for that, the value of the composed measurement error in its normalized way. Next, it diers if either an error has occurred, or if more than one type of error occurred. The correction to be made in the line parameter or the measurement with gross error is the correspondent composed normalized error. The proposed approach in this paper requires only a set of measures, and at the same instant. To validate the software, several simulations were performed in the IEEE 14-bus and 57-bus systems.
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Scarfo, Lucia. "Errori nelle dimostrazioni: tra logica ed esperienza didattica." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8757/.
Повний текст джерелаАнотація:
Il lavoro nasce dall'esigenza di comprendere quali sono gli ostacoli concettuali e metodologici che gli studenti della scuola secondaria di secondo grado incontrano nello studio delle dimostrazioni. Tale lavoro è in parte dedicato alla descrizione, mediante la proposizione di ragionamenti scorretti, delle tipologie più diffuse di errori commessi nel condurre una dimostrazione, partendo dall'esplicitazione dei requisiti necessari della stessa in contesto logico. La realizzazione di un’esperienza didattica rivolta a studenti delle classi seconde, ha permesso di concretizzare le ipotesi avanzate durante la fase descrittiva. In particolare ha favorito l’individuazione di ulteriori spunti di riflessione su come condurre lo studio delle dimostrazioni e ha messo in evidenza come un’analisi che prescinde dal piano epistemologico risulta fuorviante e inappropriata.
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Miller, Scott N. "Scale effects of geometric complexity, misclassification error and land cover change in distributed hydrologic modeling." Diss., The University of Arizona, 2002. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2002_216_sip1_w.pdf&type=application/pdf.
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Ekberg, Joakim. "Geometries of Binary Constant Weight Codes." Thesis, Karlstad University, Division for Engineering Sciences, Physics and Mathematics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-88.
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This thesis shows how certain classes of binary constant weight codes can be represented geometrically using linear structures in Euclidean space. The geometric treatment is concerned mostly with codes with minimum distance 2(w - 1), that is, where any two codewords coincide in at most one entry; an algebraic generalization of parts of the theory also applies to some codes without this property. The presented theorems lead to a total of 18 improvements of the table of lower bounds on A(n,d,w) maintained by E. M. Rains and N. J. A. Sloane. Additional improvements have been made by finding new lexicographic codes.
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Neto, Leoncio Claro de Barros. "Modelagem em geometria digital aprimorada por técnicas adaptativas de segmentos de retas." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3141/tde-11082011-135522/.
Повний текст джерелаАнотація:
Visando representar linhas retas digitais, segmentos digitalizados e arcos, cada uma das linhas de pesquisa disponíveis apresenta suas vantagens e aplicações apropriadas. No entanto, considerando as complexidades de cenários do mundo real, o uso dessas representações não é tão popular em situações que requerem modelos flexíveis ou envolvendo interferências espúrias. As tecnologias adaptativas são formalismos da ciência da computação capazes de alterar seu comportamento dinamicamente, sem a interferência de agentes externos, em resposta a estímulos de entrada. Ao serem capazes de responder às mencionadas condições variáveis do ambiente, os dispositivos adaptativos naturalmente tendem a apresentar a flexibilidade requerida para atuarem em cenários dinâmicos. Assim, este trabalho investiga uma alternativa fundamentada no autômato finito adaptativo por meio do dispositivo denominado segmento digitalizado adaptativo, que incorpore o poder expressivo de representar parâmetros desses segmentos. Dentre esses parâmetros destacam-se a capacidade de representar as tolerâncias, a escalabilidade, os erros causados por desvios em ângulo ou em comprimento dos segmentos mencionados, resultando em estruturas mais flexíveis. Considerando que os métodos sintáticos são estruturais, os segmentos digitalizados adaptativos são modelados por conjuntos de regras, partindo-se de primitivas, concebendo-se as funções adaptativas correspondentes para alteração dos estados e de regras de transição. Posteriormente, estruturas mais elaboradas são concebidas relacionadas a arcos digitais pelos quais cadeias (strings) estimulam, em um passo único, autômatos finitos adaptativos que implementam segmentos digitalizados adaptativos. As implementações utilizam uma ferramenta cujo núcleo é um simulador para edição dos arquivos que compõem os autômatos. Consequentemente, o método proposto torna-se uma alternativa relativamente simples e intuitiva comparando-se com as abordagens existentes, apresentando capacidade de aprendizagem, além de ser computacionalmente poderosa.For the representation of digital straight lines, digitized straight line segments and arcs, each of the available research approaches has its advantages and suitable applications. However, taking into account the complexities of real-world scenarios, the use of these representations is not so popular in situations that require flexible models or involving spurious interferences. Adaptive technologies are computer science formalisms able to change their behavior dynamically, without the interference of external agents, in response to incoming stimuli. By being able to respond to changing environmental conditions, adaptive devices naturally tend to have the required flexibility to work in dynamic scenarios. Thus, the purpose of this study is to investigate an alternative based on adaptive finite automaton through the device called adaptive digitized straight line segment, incorporating the expressive power to represent parameters of these segments. Among these parameters, emphasis is given to the ability to represent tolerances, scalability or errors caused by deviations in angle or length of the mentioned segments, resulting in more flexible structures. Whereas syntactic methods are structural, adaptive digitized straight line segments are modeled by sets of rules, starting from primitives, conceiving the corresponding adaptive functions to amend the set of states and transition rules. Later, more elaborate structures are designed related to digital arcs the corresponding strings of which stimulate, in just a single step, adaptive finite automata that implement adaptive digitized straight line segments. The implementations use a simulator for editing the files that compose the automata. Consequently, the proposed method reveals to be a simple and intuitive alternative capable of learning, besides being computationally powerful.
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Guenda, Kenza. "On algebraic geometric codes and some related codes." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/2033.
Повний текст джерелаАнотація:
Thesis (MSc (Mathematics))--University of Stellenbosch, 2006.The main topic of this thesis is the construction of the algebraic geometric codes (Goppa codes), and their decoding by the list-decoding, which allows one to correct beyond half of the minimum distance. We also consider the list-decoding of the Reed–Solomon codes as they are subclass of the Goppa codes, and the determination of the parameters of the non primitive BCH codes. AMS Subject Classification: 4B05, 94B15, 94B35, 94B27, 11T71, 94B65,B70. Keywords: Linear codes, cyclic codes, BCH codes, Reed–Solomon codes, list-decoding, Algebraic Geometric codes, decoding, bound on codes, error probability.
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ACHARYA, SRIKANTH B. "A MULTIVARIATE STATISTICAL ANALYSIS ON THE SAMPLING UNCERTAINTIES OF GEOMETRIC AND DIMENSIONAL ERRORS FOR CIRCULAR FEATURES." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1113427839.
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Holroyd, Geoffrey. "The modelling and correction of ball-screw geometric, thermal and load errors on CNC machine tools." Thesis, University of Huddersfield, 2007. http://eprints.hud.ac.uk/id/eprint/2627/.
Повний текст джерелаАнотація:
In the modern global economy, there is a demand for high precision in manufacture as competitive pressures drive businesses to seek greater productivity. This results in a demand for a reduction in the errors associated with CNC machine tools. To this end, it is useful to develop a greater understanding of the mechanisms which give rise to errors in machine tool drives. This programme of research covers the geometric, thermal and load errors commonly encountered on CNC machine tools. Several mathematical models have been developed or extended which enable a deeper understanding of the interaction between these errors, various details of ballscrew design and the dynamic behaviour of ballscrew driven systems. Some useful models based on the discrete matter or “lumped mass” approach have been devised. One extends the classical eigenvalue method for finding the natural frequencies and other dynamic characteristics of ballscrew systems to include viscous damping effects using a generalised eigenvalue approach. This gives the damping coefficient of each predicted vibration mode along with the estimates of the natural frequencies, enabling many of the natural frequencies predicted by standard undamped natural frequency analyses to be dismissed as being of little consequence to the vibratory behaviour of the system. A development of this modelling method gives the sensitivity of the system to changes in stiffness and damping characteristics, which is helpful at the preliminary design stage of a ballscrew system, and is an aid in deciding the most convenient remedy to vibration problems which may occur in service. The second set of lumped-mass models is specially developed to take account of the changes in the configuration of the system with time as the nut moves along the screw while taking into account the non-linear phenomena of backlash and Coulomb friction. These can deal with the axial, torsional and transverse degrees of freedom of the system and predict many aspects of the dynamic behaviour of a ballscrew system which have an effect on the errors arising from such systems. They also include features which calculate the energy converted to heat by all the energy dissipative mechanisms in the model which can be used in conjunction with models already developed at the University of Huddersfield to predict thermal errors. Further, a strategy for compensation of some of these errors has been devised
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Harris, John O. Spence Allan D. "Geometric and quasi-static thermal error compensation of a laser digitizer on a coordinate measuring machine." *McMaster only, 2004.
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Cerardi, Andrea. "CARATTERIZZAZIONE MECCANICA, GEOMETRICA E FUNZIONALE DI DISPOSITIVI BIOMEDICALI." Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3427007.
Повний текст джерелаАнотація:
Aim of this work is to develop and to validate a structured methodology to investigate mechanical, geometric and functional aspects having a direct impact on the quality and safety of the dental prosthesis.
Dental technicians are liable for damages when prosthesis are used. It’s clear from a review of the normative technical documentation as well as of the technical-scientific literature, that safety requirements are not universally accepted and, thus, not yet adopted in the design phase of the prosthesis production. Therefore operators rely on good manufacturing practices more than in inspection and testing investigations. Moreover new methods and technologies are introduced in the production process of dental prosthesis, which have made it increasingly difficult to assess the impact of methodological issues on functional, quality and safety requirements.
For these aspects, with reference to technical standards and scientific background, eight type of test were developed that were submitted to a sample of dental laboratories. Tests concern structural properties, geometric precision and functional aspects of dental devices.
The proposed tests and the results of the experimental campaign are presented. The results allow assessing the suitability of the proposed method for the characterization of medical devices under study and on that basis, for the definition of quality and safety requirements to be adopted in the design phase and process control.Obiettivo del lavoro è sviluppare e validare metodologie che permettano di investigare in modo sistematico gli aspetti meccanici, geometrici e funzionali che hanno un impatto diretto sulle caratteristiche di qualità e sicurezza dei dispositivi biomedicali. I fabbricanti del dispositivo medico sono i primi responsabili nel caso in cui si manifestassero dei danni arrecati all’utente durante il corretto utilizzo. Da un’analisi della normativa vigente e dalla letteratura tecnica-scientifica del settore è emerso che i requisiti di sicurezza non risultano accettati universalmente e quindi non sono adottati nella fase di progettazione delle protesi. Ciò fa si che gli operatori del settore si affidino alle buone pratiche di fabbricazione in sostituzione dei controlli e prove finalizzate a limitare i rischi di insuccesso. Inoltre l’introduzione di nuovi metodi e tecnologie nel processo produttivo dei dispositivi dentali aumenta le difficoltà nel valutare la ricaduta delle scelte metodologiche sul rispetto dei requisiti funzionali, di qualità e di sicurezza. Per tale ragione, in riferimento alle norme vigenti e al background scientifico, otto tipologie di prove sono state sviluppate e sottoposte a laboratori odontotecnici. Le prove hanno riguardato la verifica strutturale dei dispositivi, il controllo della precisione geometrica e gli aspetti funzionali delle protesi in esercizio. Nel seguito sono descritte le modalità di prova e presentati i risultati della campagna sperimentale effettuata. I risultati consentono di osservare come il metodo proposto sia adatto alla caratterizzazione dei dispositivi medici oggetto dello studio e che su tale base si può pervenire alla definizione di requisiti di qualità e sicurezza condivisi e pertanto utilizzabili in sede progettuale e di controllo di processo.
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Horvath, Matthew Steven. "Extension of Polar Format Scene Size Limits to Squinted Geometries." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1334013246.
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Zha, Wentao. "Geometric Approaches to Input File (STL) Modification for Part Quality Improvement in Additive Manufacturing." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1448037974.
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Aydin, Ayhan. "Geometric Integrators For Coupled Nonlinear Schrodinger Equation." Phd thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12605773/index.pdf.
Повний текст джерелаАнотація:
Multisymplectic integrators like Preissman and six-point schemes and a semi-explicit symplectic method are applied to the coupled nonlinear Schrödinger equations (CNLSE). Energy, momentum and additional conserved quantities are preserved by the multisymplectic integrators, which are shown using modified equations. The multisymplectic schemes are backward stable and non-dissipative. A semi-explicit method which is symplectic in the space variable and based on linear-nonlinear, even-odd splitting in time is derived. These methods are applied to the CNLSE with plane wave and soliton solutions for various combinations of the parameters of the equation. The numerical results confirm the excellent long time behavior of the conserved quantities and preservation of the shape of the soliton solutions in space and time.
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Gorgorió, Solà Núria. "Estratègies, dificultats i errors en els aprenentatges de les habilitats espacials." Doctoral thesis, Universitat Autònoma de Barcelona, 1994. http://hdl.handle.net/10803/4717.
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Iyer, Vipin V. "Face Milling Simulation to Correlate and Predict The Effects of Machine Tool Geometric Errors on Part Flatness Tolerance." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406881376.
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Panek, Luciano. "Edificios de tits, aplicações a teoria dos codigos e sistemas geometricos." [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306885.
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Orientador : Marcelo FirerDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica
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Mestrado
Mestre em Matemática
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Giovanzana, Stefano. "A virtual environment for modeling and analysis of human eye." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3427528.
Повний текст джерелаАнотація:
The aim of this work is to develop a virtual environment for modelling and analyse individual virtual eyes which are able to integrate the modern imaging techniques input data. This environment is realized in 3D CAD software by means of specific plug-ins. The tools for analysing the virtual eye are based on ray-tracing and curvature analysis, while the shape of the eye is represented by NURBS or mesh surfaces. This thesis develops, and validates the use of, the plug-ins for the modelization of virtual eyes inside a 3D CAD environment; in particular a novel lens model whose shape is linked to geometrical and optical constraints was created. Shape was also tested on real crystalline images obtained with shadow photogrammetry. Moreover real eye topography was used for modelization of anterior cornea and preliminary results from ray tracing are shown. This model and the ray-tracing tools may be used in future works for design of ophthalmic, contact or intraocular lenses, specifically customised of a single ametropy.Lo scopo di questo lavoro è stato quello di sviluappare un ambiente virtuale per la modellazione e l’analisi di un occhio virtuale personalizzato, che fosse in grado di integrare le moderne tecniche di analisi ottica come dati di ingresso. Questo ambiente è stato sviluppato all’interno di un software CAD tramite l’ultilizzo di plug-in specifici. Gli strumenti utilizzati per analizzare l’occhio virtuale sono basati sul ray-tracing e sull’analisi di curvatura, mentre la geometria dell’occhio è stata modellizzata tramite l’utilizzo di superfici NURBS o mesh. La presente tesi sviluppa, e valida l’utilizzo, di codesti plug-in per la modellizzazione di un occhio virtuale in un ambiente CAD 3D; in particolare è stato creato un modello innovativo di lente, la cui forma è legata a vincoli geometrici ed ottici. La forma di tale lente è stata confrontata con cristallini reali le cui immagini sono state ottenute tramite fotografia ad ombra. Inoltre la topografia di un occho reale è state utilizzata per modellare la superficie anteriore della cornea e sono quindi riportati i risultati preliminari del ray-tracing. Questo modello e gli strumenti di ray-tracing utilizzati potranno essere utilizzati in futuro per la progettazione di lenti oftalmiche, a contatto o intraoculari specificatamente costumizzate sulle esigenze dell’ametrope.
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Leão, Jose Augusto. "Erros topologicos na estimação de Estados em sistemas de potencia: abordagem geometrica, detectabilidade e identificação." reponame:Repositório Institucional da UFSC, 1990. http://repositorio.ufsc.br/xmlui/handle/123456789/75628.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina. Centro TecnologicoMade available in DSpace on 2012-10-16T02:58:19Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-08T16:37:59Z : No. of bitstreams: 1 79161.pdf: 2828601 bytes, checksum: 202014ba9a2a7717df5e2057704620ed (MD5)
A atenção do trabalho se concentra no tratamento de erros de topologia na estimação de estados em sistemas de potência. O problema da estimação de estados em sistemas de potência de erros grosseiros são analisados com o uso de argumentos geométricos. Os efeitos dos erros de topologia são estudados e interpretados geometricamente. As condições para a detectabilidade dos erros são estabelecidas com o uso do conceito de medidas críticas. Um método para a detecção e localização de erros topológicos baseados na análise de sensibilidade dos resíduos com respeito aos fluxos nas linhas é proposto e testado. O método também permite o discernimento entre erros grosseiros em medidas e erros de topologia.
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Das, Paramita. "Optimum Part Build Orientation in Additive Manufacturing for Minimizing Part Errors and Build Time." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1467988134.
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Pokorný, Zdeněk. "Zpracování dat z měření na obráběcích strojích." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382195.
Повний текст джерелаАнотація:
The Master’s thesis deals with the precision of machine tools, especially with the three-axis vertical milling machine. It is structurally divided into a theoretical and practical part. While the theoretical part focuses on problems of geometric errors and measuring devices, the practical one is devoted to the machine tool being tested. In this case, the data processing and the proposed statistical analysis are essential, and at the end of the thesis another possible way of developing the data processing is outlined.