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Isogeometric analysis based on geometric reconstruction models

《机械工程前沿（英文）》 2021年 第16卷 第4期   页码 782-797 doi: 10.1007/s11465-021-0648-0

摘要： In isogeometric analysis (IGA), the boundary representation of computer-aided design (CAD) and the tensor-product non-uniform rational B-spline structure make the analysis of three-dimensional (3D) problems with irregular geometries difficult. In this paper, an IGA method for complex models is presented by reconstructing analysis-suitable models. The CAD model is represented by boundary polygons or point cloud and is embedded into a regular background grid, and a model reconstruction method is proposed to obtain the level set function of the approximate model, which can be directly used in IGA. Three 3D examples are used to test the proposed method, and the results demonstrate that the proposed method can deal with complex engineering parts reconstructed by boundary polygons or point clouds.

关键词： isogeometric analysis     reconstruction model     level set function     trimmed element     point cloud    

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Extrapolation reconstruction of wind pressure fields on the claddings of high-rise buildings

Yehua SUN, Guquan SONG, Hui LV

《结构与土木工程前沿（英文）》 2019年 第13卷 第3期   页码 653-666 doi: 10.1007/s11709-018-0503-5

摘要： Recent research about reconstruction methods mainly used the interpolation reconstruction of the fluctuating wind pressure field on the surface. However, to investigate wind pressure at the edge of the building, the work presented in this paper focuses on the extrapolation reconstruction of wind pressure fields. Here, we propose an improved proper orthogonal decomposition (POD) and Kriging method with a von Kármán correlation function to resolve this issue. The studies show that it works well for not only interpolation reconstruction but also extrapolation reconstruction. The proposed method does require determination of the Hurst exponent and other parameters analysed from the original data. Hence, the fluctuating wind fields have been characterized by the von Kármán correlation function, as an a priori function. Compared with the cubic spline method and different variogram, preliminary results suggest less time consumption and high efficiency in extrapolation reconstruction at the edge.

关键词： extrapolation reconstruction     proper orthogonal decomposition     Kriging method     von Kármán function     Hurst exponent     rescaled range analysis    

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The stem cell and tissue engineering research in Chinese ophthalmology

GE Jian, LIU Jingbo

《医学前沿（英文）》 2007年 第1卷 第1期   页码 6-10 doi: 10.1007/s11684-007-0002-x

摘要： Much has been considerably developed recently in the ophthalmic research of stem cell (SC) and tissue engineering (TE). They have become closer to the clinical practice, standardized and observable. Leading edge research of SC and TE on the ocular surface reconstruction, neuroregeneration and protection, and natural animal model has become increasingly available. However, challenges remain on the way, especially on the aspects of function reconstruction and specific differentiation. This paper reviews the new developments in this area with an intention of identifying research priorities for the future.

关键词： available     observable     neuroregeneration     protection     function reconstruction    

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光场成像技术：模型、标定、重建及应用 Review

Hao ZHU, Qing WANG, Jingyi YU

《信息与电子工程前沿（英文）》 2017年 第18卷 第9期   页码 1236-1249 doi: 10.1631/FITEE.1601727

摘要： 光场成像是计算摄像学领域一项新兴技术。基于对成像模型和光路的创新设计，光场相机不仅记录了三维物体的空间强度，而且捕获了物理世界中的角度信息。这为解决三维重建、显著区域检测、目标识别等计算机视觉问题提供了新途径。本文首先回顾了光场相机的三个关键问题，包括成像模型、标定理论以及重建方法。然后，系统介绍了光场成像技术在信息学、物理学、医学和生物学等领域的应用现状。最后，讨论了光场成像目前存在的问题，并展望了光场成像技术的应用前景。

关键词： 光场成像；全光函数；成像模型；标定；重建    

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Fractal characteristic evaluation and interpolation reconstruction for surface topography of drilled

《机械工程前沿（英文）》 2021年 第16卷 第4期   页码 840-854 doi: 10.1007/s11465-021-0643-5

摘要： In this paper, an improved fractal interpolation model is proposed to reconstruct the surface topography of composite hole wall. This model adopts the maximum positive deviations and maximum negative deviations between the measured values and trend values to determine the contraction factors. Hole profiles in 24 directions are measured. Fractal parameters are calculated to evaluate the measured surface profiles. The maximum and minimum fractal dimension of the hole wall are 1.36 and 1.07, whereas the maximum and minimum fractal roughness are 4.05 × 10 −5 and 4.36 × 10 −10 m, respectively. Based on the two-dimensional evaluation results, three-dimensional surface topographies in five typical angles (0°, 45°, 90°, 135°, and 165°) are reconstructed using the improved model. Fractal parameter D s and statistical parameters Sa, Sq, and Sz are used to evaluate the reconstructed surfaces. Average error of D s, Sa, Sq, and Sz between the measured surfaces and the reconstructed surfaces are 1.53%, 3.60%, 5.60%, and 9.47%, respectively. Compared with the model in published literature, the proposed model has equal reconstruction effect in relatively smooth surface and is more advanced in relatively rough surface. Comparative results prove that the proposed model for calculating contraction factors is more reasonable.

关键词： surface topography     fractal evaluation     fractal interpolation     reconstruction     composite    

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Full-field dynamic strain reconstruction of an aero-engine blade from limited displacement responses

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0731-1

摘要： Blade strain distribution and its change with time are crucial for reliability analysis and residual life evaluation in blade vibration tests. Traditional strain measurements are achieved by strain gauges (SGs) in a contact manner at discrete positions on the blades. This study proposes a method of full-field and real-time strain reconstruction of an aero-engine blade based on limited displacement responses. Limited optical measured displacement responses are utilized to reconstruct the full-field strain. The full-field strain distribution is in-time visualized. A displacement-to-strain transformation matrix is derived on the basis of the blade mode shapes in the modal coordinate. The proposed method is validated on an aero-engine blade in numerical and experimental cases. Three discrete vibrational displacement responses measured by laser triangulation sensors are used to reconstruct the full-field strain over the whole operating time. The reconstructed strain responses are compared with the results measured by SGs and numerical simulation. The high consistency between the reconstructed and measured results demonstrates the accurate strain reconstructed by the method. This paper provides a low-cost, real-time, and visualized measurement of blade full-field dynamic strain using displacement response, where the traditional SGs would fail.

关键词： aero-engine blade     displacement response     dynamic strain reconstruction     mode shape     strain gauge    

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Shape reconstruction of parallelogram flaw

ZHENG Gangfeng, WU Bin, HE Cunfu

《机械工程前沿（英文）》 2008年 第3卷 第1期   页码 17-22 doi: 10.1007/s11465-008-0015-4

摘要： To reconstruct the shape of the scatterer in elastic media, the authors deduce the Born approximation solution of the two-dimensional scattering problem, which includes the shape factor that embodies all information about the shape of the scatterer. Accordingly, the change in the shape of the scatterer only necessitates the number of the corresponding new shape factors. For a parallelogram void in a long Al rod, its shape factor can be obtained. In view of the definition of a characteristic function, the shape factor has a corresponding integral representation. Obviously, the shape factor can be considered as a Fourier transform of the characteristic function, which is reconstructed from the inverse Fourier transform. The integral equation is considered as the basic equation to reconstruct the shape of the scatterer. The identification of the geometrical character of a flaw is then given by the two dimensional inverse Born approximation in a low-frequency range. For the parallelogram void, a theoretical calculating identification is performed. At the same time, the numerical results are obtained by the finite element method.

关键词： approximation     scatterer     scattering problem     information     inverse    

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The ecological system and the regionalization of landscape reconstruction in northwest of China

Peicheng LI,Guoyuan DU,Qilei LI,Jinfeng WANG,Feimin ZHENG

《农业科学与工程前沿（英文）》 2014年 第1卷 第4期   页码 291-298 doi: 10.15302/J-FASE-2014033

摘要： The northwest of China is a vast area with abundant resources and significant potential for development. However, the ecological system is extremely vulnerable to damage and must be managed carefully. Thus, the Chinese government is strengthening research on improvement and reconstruction of the ecological system and landscape in northwest of China while moving forward with large-scale development in west China. The disadvantages and vulnerabilities in the northwest area in China are presented. It is suggested that the reconstruction of landscape should be conducted by step by step regionalization across the various ecological systems in the 3.04 million km northwest area of China. The first level regionalization results of reconstruction of landscape are discussed.

关键词： reconstruction of landscape     ecological system     the northwest area of China     science and technology action    

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A dynamic stiffness-based framework for harmonic input estimation and response reconstruction considering

Yixian LI; Limin SUN; Wang ZHU; Wei ZHANG

《结构与土木工程前沿（英文）》 2022年 第16卷 第4期   页码 448-460 doi: 10.1007/s11709-022-0805-5

摘要： In structural health monitoring (SHM), the measurement is point-wise but structures are continuous. Thus, input estimation has become a hot research subject with which the full-field structural response can be calculated with a finite element model (FEM). This paper proposes a framework based on the dynamic stiffness theory, to estimate harmonic input, reconstruct responses, and to localize damages from seriously deficient measurements. To begin, Fourier transform converts the dynamic equilibrium equation to an equivalent static one in the frequency domain, which is under-determined since the dimension of measurement vector is far less than the FEM-node number. The principal component analysis has been adopted to “compress” the under-determined equation, and formed an over-determined equation to estimate the unknown input. Then, inverse Fourier transform converts the estimated input in the frequency domain to the time domain. Applying this to the FEM can reconstruct the target responses. If a structure is damaged, the estimated nodal force can localize the damage. To improve the damage-detection accuracy, a multi-measurement-based indicator has been proposed. Numerical simulations have validated that the proposed framework can capably estimate input and reconstruct multi-types of full-field responses, and the damage indicator can localize minor damages even with the existence of noise.

关键词： dynamic stiffness     principal component analysis     response reconstruction     damage localization     under-determined equation    

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Development of surface reconstruction algorithms for optical interferometric measurement

Dongxu WU, Fengzhou FANG

《机械工程前沿（英文）》 2021年 第16卷 第1期   页码 1-31 doi: 10.1007/s11465-020-0602-6

摘要： Optical interferometry is a powerful tool for measuring and characterizing areal surface topography in precision manufacturing. A variety of instruments based on optical interferometry have been developed to meet the measurement needs in various applications, but the existing techniques are simply not enough to meet the ever-increasing requirements in terms of accuracy, speed, robustness, and dynamic range, especially in on-line or on-machine conditions. This paper provides an in-depth perspective of surface topography reconstruction for optical interferometric measurements. Principles, configurations, and applications of typical optical interferometers with different capabilities and limitations are presented. Theoretical background and recent advances of fringe analysis algorithms, including coherence peak sensing and phase-shifting algorithm, are summarized. The new developments in measurement accuracy and repeatability, noise resistance, self-calibration ability, and computational efficiency are discussed. This paper also presents the new challenges that optical interferometry techniques are facing in surface topography measurement. To address these challenges, advanced techniques in image stitching, on-machine measurement, intelligent sampling, parallel computing, and deep learning are explored to improve the functional performance of optical interferometry in future manufacturing metrology.

关键词： surface topography     measurement     optical interferometry     coherence envelope     phase-shifting algorithm    

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Ontological reconstruction of the clinical terminology of traditional Chinese medicine

null

《医学前沿（英文）》 2014年 第8卷 第3期   页码 358-361 doi: 10.1007/s11684-014-0348-9

摘要：

This study proposes the ontological reconstruction of the current clinical terminology of traditional Chinese medicine (TCM). It also provides an overview of preliminary work related to the said reconstruction, including the ontology-based analysis of TCM clinical terminology. We conclude that the ontological reconstruction of TCM clinical terminology provides a proper translation from the idealized organizational model to real-world implementation and to a formalized, shared, and knowledge-based framework.

关键词： ontology     traditional Chinese medicine     clinical terminology    

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Animage-based approach to the reconstruction of ancient architectures by extracting and arranging 3D

Divya Udayan J,HyungSeok KIM,Jee-In KIM

《信息与电子工程前沿（英文）》 2015年 第16卷 第1期   页码 12-27 doi: 10.1631/FITEE.1400141

摘要： The objective of this research is the rapid reconstruction of ancient buildings of historical importance using a single image. The key idea of our approach is to reduce the infinite solutions that might otherwise arise when recovering a 3D geometry from 2D photographs. The main outcome of our research shows that the proposed methodology can be used to reconstruct ancient monuments for use as proxies for digital effects in applications such as tourism, games, and entertainment, which do not require very accurate modeling. In this article, we consider the reconstruction of ancient Mughal architecture including the Taj Mahal. We propose a modeling pipeline that makes an easy reconstruction possible using a single photograph taken from a single view, without the need to create complex point clouds from multiple images or the use of laser scanners. First, an initial model is automatically reconstructed using locally fitted planar primitives along with their boundary polygons and the adjacency relation among parts of the polygons. This approach is faster and more accurate than creating a model from scratch because the initial reconstruction phase provides a set of structural information together with the adjacency relation, which makes it possible to estimate the approximate depth of the entire structural monument. Next, we use manual extrapolation and editing techniques with modeling software to assemble and adjust different 3D components of the model. Thus, this research opens up the opportunity for the present generation to experience remote sites of architectural and cultural importance through virtual worlds and real-time mobile applications. Variations of a recreated 3D monument to represent an amalgam of various cultures are targeted for future work.

关键词： Digital reconstruction     3D virtual world     3D spatial components     Vision and scene understanding    

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Three-dimensional reconstruction of light microscopy image sections: present and future

null

《医学前沿（英文）》 2015年 第9卷 第1期   页码 30-45 doi: 10.1007/s11684-014-0337-z

摘要：

Three-dimensional (3D) image reconstruction technologies can reveal previously hidden microstructures in human tissue. However, the lack of ideal, non-destructive cross-sectional imaging techniques is still a problem. Despite some drawbacks, histological sectioning remains one of the most powerful methods for accurate high-resolution representation of tissue structures. Computer technologies can produce 3D representations of interesting human tissue and organs that have been serial-sectioned, dyed or stained, imaged, and segmented for 3D visualization. 3D reconstruction also has great potential in the fields of tissue engineering and 3D printing. This article outlines the most common methods for 3D tissue section reconstruction. We describe the most important academic concepts in this field, and provide critical explanations and comparisons. We also note key steps in the reconstruction procedures, and highlight recent progress in the development of new reconstruction methods.

关键词： microtomy     3D imaging     computer-assisted image processing     3D printing     tissue scaffold    

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Lung function and air pollution exposure in adults with asthma in Beijing: a 2-year longitudinal panel

《医学前沿（英文）》 2022年 第16卷 第4期   页码 574-583 doi: 10.1007/s11684-021-0882-1

摘要： The effect of air pollution on the lung function of adults with asthma remains unclear to date. This study followed 112 patients with asthma at 3-month intervals for 2 years. The pollutant exposure of the participants was estimated using the inverse distance weight method. The participants were divided into three groups according to their lung function level at every visit. A linear mixed-effect model was applied to predict the change in lung function with each unit change in pollution concentration. Exposure to carbon monoxide (CO) and particles less than 2.5 micrometers in diameter (PM2.5) was negatively associated with large airway function in participants. In the severe group, exposure to chronic sulfur dioxide (SO2) was negatively associated with post-bronchodilator forced expiratory flow at 50%, between 25% and 75% of vital capacity % predicted (change of 95% CI per unit: −0.34 (−0.55, −0.12), −0.24 (−0.44, −0.03), respectively). In the mild group, the effect of SO2 on the small airways was similar to that in the severe group, and it was negatively associated with large airway function. Exposure to CO and PM2.5 was negatively associated with the large airway function of adults with asthma. The negative effects of SO2 were more evident and widely observed in adults with severe and mild asthma than in adults with moderate asthma. Patients with asthma react differently to air pollutants as evidenced by their lung function levels.

关键词： lung function     asthma     air pollution     adult    

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我国村镇未来发展的若干趋势判断

曹璐,谭静,魏来,陈宇,蒋鸣,卓佳,华传哲,冯旭,许顺才

《中国工程科学》 2019年 第21卷 第2期   页码 6-13 doi: 10.15302/J-SSCAE-2019.02.011

摘要：

本文通过实地调研和大数据分析相结合的方式，探索我国村镇发展的当前特点及发展趋势。总体而言，预计我国村镇未来将延续三大发展趋势：一是城乡长期共存、农村适度集聚，小城镇在衰落时期正面临新的发展机遇；二是预计未来东中西部的城乡将以不同模式集聚，小城镇内部的分化趋势加剧；三是随着村镇产业的转型升级，新功能、新业态将进入乡村地区；四是随着乡村经济发展水平的持续提升，基本公共服务供给成为基层村镇建设的重点，并进一步影响村镇空间格局的整合重构。

关键词： 适度集聚     分化趋势     新功能     新业态     新增长点     空间重构     基本公共服务供给    

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标题 作者 时间 类型 操作

Isogeometric analysis based on geometric reconstruction models

期刊论文

Extrapolation reconstruction of wind pressure fields on the claddings of high-rise buildings

Yehua SUN, Guquan SONG, Hui LV

期刊论文

The stem cell and tissue engineering research in Chinese ophthalmology

GE Jian, LIU Jingbo

期刊论文

光场成像技术：模型、标定、重建及应用

Hao ZHU, Qing WANG, Jingyi YU

期刊论文

Fractal characteristic evaluation and interpolation reconstruction for surface topography of drilled

期刊论文

Full-field dynamic strain reconstruction of an aero-engine blade from limited displacement responses

期刊论文

Shape reconstruction of parallelogram flaw

ZHENG Gangfeng, WU Bin, HE Cunfu

期刊论文

The ecological system and the regionalization of landscape reconstruction in northwest of China

Peicheng LI,Guoyuan DU,Qilei LI,Jinfeng WANG,Feimin ZHENG

期刊论文

A dynamic stiffness-based framework for harmonic input estimation and response reconstruction considering

Yixian LI; Limin SUN; Wang ZHU; Wei ZHANG

期刊论文

Development of surface reconstruction algorithms for optical interferometric measurement

Dongxu WU, Fengzhou FANG

期刊论文

Ontological reconstruction of the clinical terminology of traditional Chinese medicine

null

期刊论文

Animage-based approach to the reconstruction of ancient architectures by extracting and arranging 3D

Divya Udayan J,HyungSeok KIM,Jee-In KIM

期刊论文

Three-dimensional reconstruction of light microscopy image sections: present and future

null

期刊论文

Lung function and air pollution exposure in adults with asthma in Beijing: a 2-year longitudinal panel

期刊论文

我国村镇未来发展的若干趋势判断

曹璐,谭静,魏来,陈宇,蒋鸣,卓佳,华传哲,冯旭,许顺才

期刊论文