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Image meshing via hierarchical optimization

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Frontiers of Information Technology & Electronic Engineering 2016年第1期17卷 32-40页

作者： Hao XIE ruo-feng TONG Institute of Artificial Intelligence Zhejiang University

Vector graphic, as a kind of geometric representation of raster images, has many advantages, e.g.,definition independence and editing facility. A popular way to convert raster images into vector graphics is image meshing, the aim of which is to find a mesh to represent an image as faithfully as possible. For traditional meshing algorithms, the crux of the problem resides mainly in the high non-linearity and non-smoothness of the ob jective,which makes it difficult to find a desirable optimal solution. To ameliorate this situation, we present a hierarchical optimization algorithm solving the problem from coarser levels to finer ones, providing initialization for each level with its coarser ascent. To further simplify the problem, the original non-convex problem is converted to a linear least squares one, and thus becomes convex, which makes the problem much easier to solve. A dictionary learning framework is used to combine geometry and topology elegantly. Then an alternating scheme is employed to solve both parts. Experiments show that our algorithm runs fast and achieves better results than existing ones for most images.

关键词： Image meshing, Hierarchical optimization, Convexification

Finite element prediction on the response of non-uniformly arranged pile groups considering progressive failure of pile-soil system

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Frontiers of Structural and Civil Engineering 2020年第4期14卷 961-982页

作者： Qian-Qing ZHANG Shan-Wei LIU ruo-feng feng Jian-Gu QIAN Chun-Yu CUI Geotechnical and Structural Engineering Research Center Shandong UniversityJinan 250061China Key Laboratory of Geotechrical and Underground Engineering of the Minstry of Education Tongji UniversityShanghai 200092China

A uniform arrangement of individual piles is commonly adopted in the conventional pile group foundation,and basin-shaped settlement is often observed in *** differential settlement of pile groups will decrease the use-safety requirements of building,even cause the whole-building tilt or *** reduce differential settlement among individual piles,non-uniformly arranged pile groups can be *** paper presents a finite element analysis on the response of pile groups with different layouts of individual piles in pile *** the userdefined subroutine FRIC as the secondary development platform,a softening model of skin friction and a hyperbolic model of end resistance are introduced into the contact pair calculation of ABAQUS *** to the response analysis of a single pile,the reliability of the proposed secondary development method of ABAQUS software is verified using an iterative computer *** reinforcing effects of individual piles is then analyzed using the present finite element ***,the response of non-uniformly arranged pile groups,e.g.,individual piles with variable length and individual piles with variable diameter,is analyzed using the proposed numerical analysis *** suggestions on the layout of individual piles are proposed to reduce differential settlement and make full use of the bearing capacity of individual piles in pile groups for practical purposes.

关键词： numerical simulation non-uniformly arranged pile groups differential settlement pile-soil interaction

Viscosity Approximation Method for Infinitely Many Asymptotically Nonexpansive Maps in Banach Spaces

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Journal of Mathematical Research and Exposition 2011年第4期31卷 749-756页

作者： ruo feng RAO Department of Mathematics Yibin University Sichuan 644007 P. R. China

In the framework of reflexive Banach spaces satisfying a weakly continuous duality map, the author uses the viscosity approximation method to obtain the strong convergence theorem for iterations with infinitely many asymptotically nonexpansive mappings. The main results obtained in this paper improve and extend some recent results.

关键词： asymptotically nonexpansive mapping Gauge function weakly continuous duality map.

Iterative Algorithms of Common Solutions for Quasi-Variational Inclusion and Fixed Point Problems

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Journal of Mathematical Research and Exposition 2010年第4期30卷 701-715页

作者： ruo feng RAO Department of Mathematics Yibin College Sichuan 644007 P. R. China

By introducing the resolvent operator associated with a maximal monotone mapping, the author obtains a strong convergence theorem of a generalized iterative algorithm for a class of quasi-variational inclusion problem... 详细信息

关键词： variational inclusion inverse strongly monotone maximal monotone viscosity approximation method.

A Linear Approach for Depth and Colour Camera Calibration Using Hybrid Parameters

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Journal of Computer Science & Technology 2016年第3期31卷 479-488页

作者： Ke-Li Cheng Xuan Ju ruo-feng Tong Min Tang Jian Chang Jian-Jun Zhang College of Computer Science and Technology Zhejiang University Hangzhou 310027 China National Centre for Computer Animation Bournemouth University Poole BH12 5BB U.K.

Many recent applications of computer graphics and human computer interaction have adopted both colour cameras and depth cameras as input devices. Therefore, an effective calibration of both types of hardware taking different colour and depth inputs is required. Our approach removes the numerical difficulties of using non-linear optimization in previous methods which explicitly resolve camera intrinsics as well as the transformation between depth and colour cameras. A matrix of hybrid parameters is introduced to linearize our optimization. The hybrid parameters offer a transformation from a depth parametric space （depth camera image） to a colour parametric space （colour camera image） by combining the intrinsic parameters of depth camera and a rotation transformation from depth camera to colour camera. Both the rotation transformation and intrinsic parameters can be explicitly calculated from our hybrid parameters with the help of a standard QR factorisation. We test our algorithm with both synthesized data and real-world data where ground-truth depth information is captured by Microsoft Kinect. The experiments show that our approach can provide comparable accuracy of calibration with the state-of-the-art algorithms while taking much less computation time （1/50 of Herrera＇s method and 1/10 of Raposo＇s method） due to the advantage of using hybrid parameters.

关键词： camera calibration depth camera linear optimization camera pair Kinect

BADF:Bounding Volume Hierarchies Centric Adaptive Distance Field Computation for Deformable Objects on GPUs

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Journal of Computer Science & Technology 2022年第3期37卷 731-740页

作者： Xiao-Rui Chen Min Tang Cheng Li Dinesh Manocha ruo-feng Tong Laboratory of Geometry Image and Video Processing Enterprise Intelligent ComputingCollege of Computer Science and TechnologyZhejiang UniversityHangzhou 310007China Geometric Algorithms for Modeling Motionand Animation LaboratoryUniversity of MarylandMaryland 20742U.S.A.

We present a novel algorithm BADF(Bounding Volume Hierarchy Based Adaptive Distance Fields)for accelerating the construction of ADFs(adaptive distance fields)of rigid and deformable models on graphics processing *** approach is based on constructing a bounding volume hierarchy(BVH)and we use that hierarchy to generate an octree-based *** exploit the coherence between successive frames and sort the grid points of the octree to accelerate the *** approach is applicable to rigid and deformable *** GPU-based(graphics processing unit based)algorithm is about 20x--50x faster than current mainstream central processing unit based *** BADF algorithm can construct the distance fields for deformable models with 60k triangles at interactive rates on an NVIDIA GTX GeForce ***,we observe 3x speedup over prior GPU-based ADF algorithms.

关键词： distance field deformable object graphics processing unit(GPU) octree bounding volume hierarchy

Strong Convergence by the Shrinking Projection Method for a Generalized Equilibrium Problems and Hemi-Relatively Nonexpansive Mappings

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Journal of Mathematical Research and Exposition 2010年第6期30卷 1099-1107页

作者： ruo feng RAO Jia Lin HUANG Department of Mathematics Yibin UniversitySichuan 644007P.R.China

Motivated by the recent result obtained by Takahashi and Zembayashi in 2008,we prove a strong convergence theorem for finding a common element of the set of solutions of a generalized equilibrium problem and the set of fixed points of a hemi-relatively nonexpansive mapping in a Banach space by using the shrinking projection *** main results obtained in this paper extend some recent results.

关键词： hemi-relatively nonexpansive mapping generalized equilibrium problem α-inversestrongly monotone mapping.

Role of stress-activated MAP kinase P38 in cisplatin-and DTT-induced apoptosis of the esophageal carcinoma cell line Eca109

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World Journal of Gastroenterology 2005年第29期11卷 4451-4456页

作者： Qian-xian Zhang ruo feng Wei Zhang Yi Ding Ji-Yao Yang Guo-Hong Liu Department of Histoiogy and Embryology Medical College of Zhengzhou University Zhengzhou 450052 Henan Province China

AIM： To study the role of P38 kinase in esophageal cancer cell apoptosis induced by genotoxin, cisplatin and the unfolded protein response （UPR） inducer, dithiothreitol （DTT）. METHODS： Esophageal carcinoma cell line Eca109 was cultured in RPMI 1640 medium to 70% confluency and treated with either cisplatin, DTT, or cisplatin plus DTT in the presence or absence of P38 inhibitor, SB203580. The untreated cells served as the control. The esophageal carcinoma cell apoptosis was detected by agarose gel DNA ladder analysis and quantified by flow cytometry. The P38 phosphorylation was detected by immunohistochemistry using antibodies specific to phosphorylated P38 protein. RESULTS：（1） Both cisplatin and DTF induced apoptosis in the esophageal cancer cell line Eca109 as shown by DNA ladder formation; （2） As detected by antibodies specific for the phosphorylated P38 protein （p-P38）, both cisplatin and DTT treatments activated the stress-activated enzyme, MAP kinase P38. The number of positive cells was about 50% for the treatment groups, comparing to that of 10% for untreated group. DTF treatment, but not cisplatin treatment, induces nuclear localization of p-P38; （3） As measured by flow cytometry, inhibition of P38 activity by SB203580 blocks DTT- and cisplatin-induced apoptosis. The rates for DTT, cisplatin, and DTT plus cisplatin-induced apoptosis were 16.8%, 17.1%, and 21.4%, respectively. Addition of the SB compound during the incubation reduced the apoptotic rate to about 7.6% for all the treatment groups, suggesting that P38 activation is essential for cisplatin- and DTT-induced apoptosis in Eca109 cells. CONCLUSION：（1） Both DTT and cisplatin were able to induce apoptosis in esophageal cancer cell line Eca109; （2） P38 MAP kinase is essential for DTT- and cisplatininduced apoptosis in Eca109 cells; （3） P38 activation may be the common signaling component relaying the multiple upstream signaling events to the downstream cell death program.

关键词： P38MAPK Cisplatin Dithiothreitol Apoptosis Eca109 cell line

Effective synthesis of benzyl halides triggered by in situ prepared hypervalent halides

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Chinese Chemical Letters 2013年第1期24卷 45-48页

作者： Xue-Ge Ling Yan Xiong Shu-Ting Zhang ruo-feng Huang Xiao-Hui Zhang School of Chemistry and Chemical Engineering Chongqing University

An effective approach for the direct benzylhalogenation with in situ generation of hypervalent halides has been developed. A variety of benzyl halides are produced in moderate to excellent yields （up to 99%） with hi... 详细信息

关键词： Benzyl halidesBrominationHypervalentlodination