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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Optical Non-Destructive Surface Inspection and Automatic Classification of Cast Iron Automotive Part

Borwankar, Raunak 26 April 2017 (has links)
Over the past decade, research into computer vision has proliferated with the goal to incorporate artificial intelligence into a wide range of applications. These applications can be as sophisticated as intelligent assistants in smartphones and self-driving cars or as mundane as text and face recognition. While most of these applications are software based, they represent unique challenges when it comes to industrial implementation. This thesis concentrates on an optical non-destructive testing (NDT) and automatic classification methodology using customized image processing techniques. In contrast to conventional spatial analyses, which are highly susceptible to noise and human perception, our proposed transform domain approach provides a high degree of robustness and flexibility in feature selection and hence a better classification efficiency. Our presented algorithm classifies the Part-Under-Test (PUT) into two bins of either acceptable or faulty using transform domain techniques in conjunction with a classifier. Because the classification is critically dependent on the features extracted from these images, a sophisticated scalable database was created. This thesis applies transform domain techniques such as Discrete Wavelet Transform (DWT) and Rotated Wavelet Transform (RWT) for feature extraction and then classifies the PUT based on those features. Although, this approach achieves promising classification efficiency, it does not meet industrial standards. It was concluded that in order to achieve those standards, the effect of emissivity fluctuations of the PUT should be negated. The research was then extended to apply an image acquisition algorithm in the form of shape from polarization. The approach exploits the partially linearly polarization of reflected light from the PUT surface. It was observed that this method could not only detect if the PUT is faulty or fault free, but also highlight the locations of the flaws.
42

VLSI interconnected circuit simulation using time-domain characteristic model. / CUHK electronic theses & dissertations collection

January 1999 (has links)
by Ronald Siu-kwong, Ip. / "June 1999." / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (p. 89-94). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
43

Staggered discontinuous Galerkin methods for the three-dimensional Maxwell's equations on Cartesian grids.

January 2012 (has links)
在本文中,我們為了三維空間的馬克士威方程組(Maxwell’s equation)制定和分析了一套新種類的交錯間斷伽遼金(discontinuous Galerkin)方法,同時考慮了時間依賴性和時間諧波的馬克士威方程組。我們用了空間離散上交錯笛卡兒網格,這種方法具有許多良好的性質。首先,我們的方法所得出的數值解保留了電磁能量,並自動符合了高斯定律的離散版本。第二,質量矩陣是對角矩陣,從而時間推進是顯式和非常有效的。第三,我們的方法是高階準確,最佳收斂性在這裏會被嚴格地證明。第四,基於笛卡兒網格,它也很容易被執行,並可視為是典型的Yee’s Scheme的以及四邊形的邊有限元的推廣。最後,超收斂結果也會在這裏被證明。 / 在本文中,我們還提供了幾個數值結果驗證了理論的陳述。我們計算了時間依賴性和時間諧波的馬克士威方程組數值收斂結果。此外,我們計算時間諧波馬克士威方程組特徵值問題的數值特徵值,並與理論特徵值比較結果。最後,完美匹配層(Perfect Matching Layer)吸收邊界的問題也有實行其數值結果。 / We develop and analyze a new type of staggered discontinuous Galerkin methods for the three dimensional Maxwell’s equations in this paper. Both time-dependent and time-harmonic Maxwell’s equations are considered. The spatial discretization is based on staggered Cartesian grids which possess many good properties. First of all, our method has the advantages that the numerical solution preserves the electromagnetic energy and automatically fulfills a discrete version of the Gauss law. Second, the mass matrices are diagonal, thus time marching is explicit and is very efficient. Third, our method is high order accurate and the optimal order of convergence is rigorously proved. Fourth, it is also very easy to implement due to its Cartesian structure and can be regarded as a generalization of the classical Yee’s scheme as well as the quadrilateral edge finite elements. Lastly, a superconvergence result, that is the convergence rate is one order higher at interpolation nodes, is proved. / In this paper, we also provide several numerical results to verify the theoretical statements. We compute the numerical convergence order using L2-norm and discrete-norm respectively for both the time-dependent and time-harmonic Maxwell’s equations. Also, we compute the numerical eigenvalues for the time-harmonic eigenvalue problem and compare the result with the theoretical eigenvalues. Lastly, applications to problems in unbounded domains with the use of PML are also presented. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Yu, Tang Fei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 46-49). / Abstracts also in Chinese. / Chapter 1 --- Introduction and Model Problems --- p.1 / Chapter 2 --- Staggered DG Spaces --- p.4 / Chapter 2.1 --- Review on Gauss-Radau and Gaussisan points --- p.5 / Chapter 2.2 --- Basis functions --- p.6 / Chapter 2.3 --- Finite Elements space --- p.7 / Chapter 3 --- Method derivation --- p.14 / Chapter 3.1 --- Method --- p.14 / Chapter 3.2 --- Time discretization --- p.17 / Chapter 4 --- Energy conservation and Discrete Gauss law --- p.19 / Chapter 4.1 --- Energy conservation --- p.19 / Chapter 4.2 --- Discrete Gauss law --- p.22 / Chapter 5 --- Error analysis --- p.24 / Chapter 6 --- Numerical examples --- p.29 / Chapter 6.1 --- Convergence tests --- p.30 / Chapter 6.2 --- Diffraction by a perfectly conducting object --- p.30 / Chapter 6.3 --- Perfectly matched layers --- p.37 / Chapter 7 --- Time Harmonic Maxwell’s equations --- p.40 / Chapter 7.1 --- Model Problems --- p.40 / Chapter 7.2 --- Numerical examples --- p.40 / Chapter 7.2.1 --- Convergence tests --- p.41 / Chapter 7.2.2 --- Eigenvalues tests --- p.41 / Chapter 8 --- Conclusion --- p.45 / Bibliography --- p.46
44

A method for characterizing the properties of industrial foams /

Salisbury, Shaun M., January 2005 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2005. / Includes bibliographical references (p. 85-88).
45

Time domain simulation of Maxwell's equations by the method of characteristics

Orhanovic, Neven 01 October 1993 (has links)
A numerical method based on the the method of characteristics for hyperbolic systems of partial differential equations in four independent variables is developed and used for solving time domain Maxwell's equations. The method uses the characteristic hypersurfaces and the characteristic conditions to derive a set of independent equations relating the electric and magnetic field components on these hypersurfaces. A discretization scheme is developed to solve for the unknown field components at each time step. The method retains many of the good features of the original method of characteristics for hyperbolic systems in two independent variables, such as optimal time step, good behavior near data discontinuities and the ability to treat general boundary conditions. The method is exemplified by calculating the time domain response of a few typical planar interconnect structures to Gaussian and unit step excitations. Although the general emphasis is on interconnect problems, the method is applicable to a number of other transient electromagnetic field problems governed by Maxwell's equations. In addition to the method of characteristics a finite difference scheme, known in mathematic circles as the modified Richtmyer scheme, is applied to the time domain solution of Maxwell's equations. Both methods should be useful for efficient full wave analysis of three dimensional electromagnetic field problems. / Graduation date: 1994
46

The Cross-Domain Analysis of the Strategies and Decisions of the Industrial Park Sustainable Development of the Kaohsiung Region ¡X the Perspective of the Public Affairs Management Integrated Reference Framework (PAM)

Hu, I-Hsiang 10 September 2009 (has links)
Based on the Cross-Domain Analysis method of the ¡§Public Affairs Management Integrated Reference Framework,¡¨ this study analyzed the the strategies and decisions of the sustainable development of the industrial park of the Kaohsiung Region. It combine the primary data , secondary data and the qualitative research,and compare with the results of the Cognitive Continuum Theory(CCT) and the Interactive Management,(IM), in order to understand the whole picture from some dimensions. At the end of the research, it can be agreed that the Cross-Domain Analysis method of the ¡§Public Affairs Management Integrated Reference Framework¡¨ and solve the multiple opinions of diversified communities, through the ten stages of the method, we can clarified the questions and concluded the strategies. There are the conclusions of the study as the follows: (1) the study concluded the eight questions of the Sustainable Development of the Industrial Park of the Kaohsiung Region; (2) they are the key performance factors to reduce the gap of Kaohsiong and Taipei, and to enhance the relationship with the main-land China, they could promote the effiencies of the Kaohsiong Port and Kaohsiung Airport. (3) to examine the land-use of the industrial parts of Kaohsiong, and to upgrate the industrial typies could create more job opportunities;(4) to import new industries is the most important strategy; and the policy-maketing should add more the elements of the intuition; (5) it can concluded the ten strategies based on the Interactive Management(IM); (6) the first priority strategy is to establish the managerial mechanism of the cross-territories, in order to consolidate the efforts of the Central government and the Local government.
47

Theory and application of time-frequency analysis to transient phenomena in electric power and other physical systems

Shin, Yong June 28 August 2008 (has links)
Not available / text
48

New methodology for power system modeling and its application in machine modeling and simulation

Gao, Wenzhong 05 1900 (has links)
No description available.
49

Development of models for electrostatically-actuated RF-MEMS interdigitated capacitors using novel FDTD and MRTD approaches

Bushyager, Nathan Adam 08 1900 (has links)
No description available.
50

Development of time domain characterization methods for packaging structures

Pannala, Sreemala 08 1900 (has links)
No description available.

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