96 research outputs found
Locating large-scale craniofacial feature points on x-ray images for automated cephalometric analysis
No full textWith the objective of tracing out all craniofacial structures in parallel with landmarking on x-ray images in cephalometry for the first time, a novel approach is proposed to locate 262 feature points composed of 90 landmarks and 172 auxiliary points. Twelve landmarks are identified by classical image processing techniques and a pattern matching algorithm, and then are used to divide the craniofacial shape to ten independent regions according to the anatomical knowledge. For each region, principal component analysis is employed to statistically characterize its shape and the gray profile of every feature point in the training, and a modified active shape model is proposed for localization. We conclude with experiment results and some discussion. ? 2005 IEEE.EI
Fractional operators and their applications in image processing
No full textThe boundedness of operators and capacity theory are fundamental topics in harmonic analysis.
In this thesis, we focus on studying the properties of fractional operators, particularly
the fractional Laplacian and Riesz potential, along with their associated capacities. We then
extend these theoretical results to develop new models in image processing.
Image decomposition plays a crucial role in image processing. Before conducting further
analysis or modifications, such as detail enhancement or image composition, it is often
necessary to decompose an image into different components, allowing for the independent
manipulation of geometric features. As a specific case of this, image denoising
involves removing unwanted noise while preserving essential details. Given the global nature
of fractional operators compared to traditional derivatives, we propose several models
for image decomposition and image denoising, utilizing both the partial differential equation
(PDE) method and the variational method. These models are supported by numerical
simulations to demonstrate their effectiveness. Chapter 2 introduces three PDE-based models
involving the fractional Laplacian and Riesz potential for image denoising, along with
proof of the existence of solutions. Chapter 3 builds on interpolation techniques to propose
(BV; ˙W ᵅ,ᵖ,∞)-based model for image decomposition. Chapter 4 establishes the trace
principle of the Poisson-Bessel potential, a solution to the well-known Caffarelli-Silvestre
harmonic extension, from the fractional Hardy-Sobolev space to the weak Lebesgue space,
as well as its limiting case. Based on these results, we propose (Hᵅ,¹, Lq ) and (Hᵅ,¹; log)
decomposition models. Chapter 5 characterizes the fractional wave potential derived from
the Cauchy problem for time and space fractional partial differential equations and explores
its applications in wave function theory and image processing. Finally, this thesis concludes
with a summary of our findings and potential directions for future research
Computerized extraction of craniofacial anatomical structures for orthodontic analysis
No full textExtraction of craniofacial anatomical structures on cephalometric radiographs is important for observing and predicting the growth changes and evaluating the curative effect in orthodontic analysis. Due to the natural of cephalograms, it is difficult for simplex image processing approaches to exactly track both the soft tissue contours and the structure outlines of internal skull. In this paper, we address this problem by recognizing 262 landmark points and then connecting them according to the prior knowledge. Image processing, pattern matching, and modified active shape model are combined to realize the landmark recognition; subdivision curves are used to obtain the structure rendering.Computer Science, Artificial IntelligenceComputer Science, Theory & MethodsImaging Science & Photographic TechnologySCI(E)CPCI-S(ISTP)
Solving the Problem of the Link Optimizing and Delay-constrained Multicast Routing Based on GA
No full text
Shear-slip behaviour of prefabricated composite shear stud connectors in composite bridges
No full textThis paper has investigated the shear-slip behaviour of an innovative prefabricated composite shear stud (PCSS) connector and its application in the prefabricated steel–concrete composite bridges. A series of push-out tests are carried out on a total of 12 specimens, including 6 PCSS specimens and 6 conventional shear stud (CSS) specimens. Further comparison has been carried out between the test result and the data available from the literature. Based on the test, a high-resolution finite element (FE) analysis has been performed to reveal the load transfer mechanism of the PCSS connector at the component-level. After that, an advanced FE model has been established and validated by a full-scale test of the prefabricated composite bridge using the PCSS. With the FE model, the load-slip behaviour and slip distribution are investigated in details. The result highlights the enhanced shear capacity and ductility of the PCSS specimens compared with the CSS specimens, as well as the feasibility of PCSS connectors in composite bridges. Meanwhile, it is further revealed by the detailed investigation that the enhancement could be attributed to the lateral constraint on the concrete by the vertical steel plate in the PCSS. Besides, it is also found that the load-slip behaviour of composite bridges using the PCSS is influenced by the cracking at the seam between deck blocks. Consequently, abrupt changes can be found in the load-slip curve once the cracking occurs, which differs from the traditional composite bridges.Accepted Author ManuscriptSteel & Composite Structure
Application of rod-shaped cellulose nanocrystals in polyacrylamide hydrogels
No full textRod-shaped cellulose nanocrystals (CNCs) were manufactured and used to reinforce polyacrylamide (PAM) hydrogels through in situ free-radical polymerization. The gelation process of the nanocomposite hydrogels was monitored on a rheometer using oscillatory shear. The chemical structure, morphology, swelling property, and compression strength of the formed gels were investigated. A possible mechanism for forming hydrogels was proposed. The results showed that CNCs accelerated the formation of hydrogels and increased the effective crosslink density of hydrogels. Thus CNCs were not only a reinforcing agent for hydrogel, but also acted as a multifunctional cross-linker for gelation. The shear storage modulus, compression strength and elastic modulus of the nanocomposite hydrogels were significantly improved because of good dispersion of CNCs in PAM as well as enhanced interfacial interaction between these two components. Among the CNC contents used, a loading of 6.7 w/w% led to the maximum mechanical properties for nanocomposite hydrogels
The status challenge of the ethnic education in the Yanbian Korean Autonomous Prefecture
No full textYanbian Korean Autonomous Prefecture, the only one of the Korean autonomous in China, is in Jilin province, in the northeastern part of China. It is the cross region which China has the border with North Korea and Russia. Since it\u27s creation in 1952, during 50 years there is visible development in this region, especially through more than 20 years\u27 Chinese Economic Reform. However, drastic tide of the market economy and normalization of diplomatic relation between China and South Korea affect the feature and conscious of Yanbian Korean Minority. The market economy bring on terrible population problem in Yanbian Korean Society, and has much effect on various parts such as ethnic consciousness and education. At the begging of this paper, the author arrange the history and policy of the ethnic education of Yanbian Korean Autonomous Prefecture of China in the social environment as noted above. Then, the author adduce the analysis material of the precedence research and the interview census with the chairman of Yanbian Education Institute; and the survey which got in September-October 2004, for the ethnic consciousness of undergraduate Korean minority students in Yanbian university; and the survey too, which carried out in February-March 2006, for the ethnic consciousness of Grade 2 and Grade 6 students of Tumen City No.2 Korean Primary School of Yanbian Korean Autonomous Prefecture to present actual situation and future action assignment of the ethnic education for Yanbian Korean Autonomous Prefecture
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