A boundary extraction method based on Dual-T-Snakes and dynamic programming

2002 ◽  
Author(s):  
G.A. Giraldi ◽  
E. Strauss ◽  
A.A. Oliveira
Keyword(s):  
Dynamic Programming ◽  
Extraction Method ◽  
Boundary Extraction

Research on Boundary Extraction of STL Models based on Genetic Algorithm

2012 ◽  
Vol 566 ◽  
pp. 78-81
Author(s):  
Jing Bin Hao ◽  
Zhong Bin Wang ◽  
Hai Feng Yang ◽  
Zhong Kai Li
Keyword(s):  
Genetic Algorithm ◽  
Extraction Method ◽  
Least Square Method ◽  
Least Square ◽  
Threshold Method ◽  
Boundary Extraction ◽  
Large Complex ◽  
Complex Models ◽  
Curvature Information ◽  
Best Fit

To efficiently decompose a large complex STL model, an improved boundary extraction method is proposed based on genetic algorithm. Three curvature parameters (dihedral angle, perimeter ration and convexity) were used to estimate the surface curvature information. Genetic Algorithm (GA) is used to determinate the threshold of feature edge. The discrete feature edges are grouped and filtered using the best-fit plane (BFP), which is calculated by Least Square Method (LSM). Several experimental results demonstrate that the amount of feature edges is about half of the preset threshold method, and useful feature edges were reserved. The extracted feature boundaries can be directly used to decompose large complex models.

A Hybrid Method for Density-Related Topology Optimization

2019 ◽  
Vol 16 (08) ◽  
pp. 1850116 ◽  
Author(s):  
Mi Xiao ◽  
Sheng Chu ◽  
Liang Gao ◽  
Hao Li
Keyword(s):  
Topology Optimization ◽  
Hybrid Method ◽  
Isotropic Material ◽  
Extraction Method ◽  
Smooth Boundary ◽  
Support Vector ◽  
Discrete Level ◽  
Data Filtering ◽  
Boundary Extraction ◽  
Structural Boundary

In this study, a hybrid method for density-related topology optimization is proposed, which consists of two parts: the discrete level-set method (LSM) based on solid isotropic material with penalization (SIMP) and the structural boundary extraction method based on support vector machine (SVM). In the hybrid method, the SIMP method is implemented to create new holes which are inserted into the topological structure obtained by the discrete LSM. SVM is utilized for extracting the boundary of the structure obtained by the SIMP-based discrete LSM. Based on the clear boundary extracted by SVM, a smooth boundary can be further obtained after data filtering. Four numerical examples are used to test the advantages of the hybrid method.

Evaluation of the dark field method for large association of spread DNA

1978 ◽  
Vol 36 (2) ◽  
pp. 190-191
Author(s):  
Douglas C. Barker
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Mitochondrial Dna ◽  
Extraction Method ◽  
Field Method ◽  
Dark Field ◽  
Kinetoplast Dna ◽  
Field Electron ◽  
Field Electron Microscopy ◽  
Dark Field Electron

A number of satisfactory methods are available for the electron microscopy of nicleic acids. These methods concentrated on fragments of nuclear, viral and mitochondrial DNA less than 50 megadaltons, on denaturation and heteroduplex mapping (Davies et al 1971) or on the interaction between proteins and DNA (Brack and Delain 1975). Less attention has been paid to the experimental criteria necessary for spreading and visualisation by dark field electron microscopy of large intact issociations of DNA. This communication will report on those criteria in relation to the ultrastructure of the (approx. 1 x 10-14g) DNA component of the kinetoplast from Trypanosomes. An extraction method has been developed to eliminate native endonucleases and nuclear contamination and to isolate the kinetoplast DNA (KDNA) as a compact network of high molecular weight. In collaboration with Dr. Ch. Brack (Basel [nstitute of Immunology), we studied the conditions necessary to prepare this KDNA Tor dark field electron microscopy using the microdrop spreading technique.

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