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Relation among C-curve characterization diagrams

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第10期8卷 1663-1670页

作者： CAO Juan WANG Guo-zhao Institute of Computer Graphics and image Processing Department of Mathematics Zhejiang University Hangzhou 310027 China

As three control points are fixed and the fourth control point varies, the planar cubic C-curve may take on a loop, a cusp, or zero to two inflection points, depending on the position of the moving point. The plane can, therefore, be partitioned into regions labelled according to the characterization of the curve when the fourth point is in each region. This partitioned plane is called a "characterization diagram". By moving one of the control points but fixing the rest, one can induce different characterization diagrams. In this paper, we investigate the relation among all different characterization diagrams of cubic C-curves based on the singularity conditions proposed by Yang and Wang (2004). We conclude that, no matter what the C-curve type is or which control point varies, the characterization diagrams can be obtained by cutting a common 3D characterization space with a corresponding plane.

关键词： Spline C-curve Characterization diagram Singularity

A new kind of neuron model with a tunable activation function and its applications

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Science China(Technological Sciences) 1997年第1期40卷 105-112页

作者：吴佑寿赵明生丁晓青 image Processing Division Department of Electronic Engineering Tsmghua University Beijing 100084 China

A new neuron model with a tunable activation function, denoted by the TAF model, and its application are addressed. The activation function as well as the connection weights of the neuron model can be adjusted in the training process The two-spiral problem was used as an example to show how to deduce the adjustable activation function required, and how to construct and train the network by the use of the a priori knowledge of the problem. Due to the incorporation of constraints known a priori into the activation function, many novel aspects are revealed, such as small network size, fast learning and good performances. It is believed that the introduction of the new neuron model will pave a new way in ANN studies.

关键词： BP networks activation function connection weight two-spiral problem TAF network.

Predictive visual tracking based on least absolute deviation estimation

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Chinese Optics Letters 2008年第1期6卷 35-37页

作者：蔡荣太王延杰 image Processing department Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of Sciences

To cope with the occlusion and intersection between targets and the environment, location prediction is employed in the visual tracking system. Target trace is fitted by sliding subsection polynomials based on least absolute deviation （LAD） estimation, and the future location of target is predicted with the fitted trace. Experiment results show that the proposed location prediction algorithm based on LAD estimation has significant robustness advantages over least square （LS） estimation, and it is more effective than LS-based methods in visual tracking.

关键词： Algorithms Polynomials

The structure of uniform B-spline curves with parameters

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Progress in Natural Science:Materials International 2008年第3期18卷 303-308页

作者： Juan Cao , Guozhao Wang Institute of image Processing and Computer Graphic, department of Mathematics, Zhejiang University, Hangzhou 310027, China Institute of image Processing and Computer Graphic Department of Mathematics Zhejiang University Hangzhou 310027 China

The shape-adjustable curve constructed by uniform B-spline basis function with parameter is an extension of uniform B-spline curve. In this paper, we study the relation between the uniform B-spline basis functions with parameter and the B-spline basis functions. Based on the degree elevation of B-spline, we extend the uniform B-spline basis functions with parameter to ones with multiple parameters. Examples show that the proposed basis functions provide more flexibility for curve design.

关键词： Uniform B-spline Shape parameter Shape-adjustable curve Degree elevation

Control mesh representation of a class of minimal surfaces

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第9期7卷 1544-1549页

作者： XU Gang WANG Guo-zhao Institute of Computer Graphics and image Processing Department of Mathematics Zhejiang University Hangzhou 310027 China

Minimal surface is extensively employed in many areas. In this paper, we propose a control mesh representation of a class of minimal surfaces, called generalized helicoid minimal surfaces, which contain the right helicoid and catenoid as special examples. We firstly construct the Bézier-like basis called AHT Bézier basis in the space spanned by {1, t, sint, cost, sinht, cosht}, t∈[0,α], α∈[0,5π/2]. Then we propose the control mesh representation of the generalized helicoid using the AHT Bézier basis. This kind of representation enables generating the minimal surfaces using the de Casteljau-like algorithm in CAD/CAGD mod- elling systems.

关键词： Minimal surface Helicoid surface Catenoid Control mesh

An extension of Bernstein-Bezier surface over the triangular domain

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Progress in Natural Science:Materials International 2007年第3期17卷 352-357页

作者： CAO Juan and WANG Guozhao (Institute of image Processing and Computer Graphic, department of Mathematics, Zhejiang University, Hangzhou 310027, China) Institute of image Processing and Computer Graphic Department of Mathematics Zhejiang University Hangzhou 310027 China

In this paper, a set of quasi-Bernstein polynomials of degree n with one parameter is presented, which is an extension of the Bernstein polynomials over the triangular domain. Using the presented polynomials as basis functions, we construct a class of shape adjusting surfaces defined over the triangular domain with a shape parameter, namely, quasi-B-B parametric surfaces. These surfaces share many properties with the B-B parametric surfaces. In particular, when shape parameters equal 1, they degenerate to be the B-B parametric surfaces. By changing the value of the shape parameter, we can get different surfaces under the fixed control net.

关键词： triangular domain shape parameter Bezier surfaces.

Robust Face Recognition via Low-rank Sparse Representation-based Classification

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International Journal of Automation and computing 2015年第6期12卷 579-587页

作者： Hai-Shun Du Qing-Pu Hu Dian-Feng Qiao Ioannis Pitas Institute of image Processing and Pattern Recognition Henan University department of Informatics Aristotle University of Thessaloniki

Face recognition has attracted great interest due to its importance in many real-world applications. In this paper,we present a novel low-rank sparse representation-based classification(LRSRC) method for robust face recognition. Given a set of test samples, LRSRC seeks the lowest-rank and sparsest representation matrix over all training samples. Since low-rank model can reveal the subspace structures of data while sparsity helps to recognize the data class, the obtained test sample representations are both representative and discriminative. Using the representation vector of a test sample, LRSRC classifies the test sample into the class which generates minimal reconstruction error. Experimental results on several face image databases show the effectiveness and robustness of LRSRC in face image recognition.

关键词： Face recognition image classification sparse repre

Analgesic effects of balanced acupuncture versus body acupuncture in low-back and leg pain patients with lumbar disc herniation, as assessed by resting-state functional magnetic resonance imaging

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Neural Regeneration Research 2012年第21期7卷 1624-1629页

作者： Yongsong Ye Bo Liu department of image Guangdong Provincial Hospital of Traditional Chinese Medicine Guangzhou 518100 Guangdong Province China

Balanced acupuncture, a single-acupoint balance therapy, regulates the balance of the cerebral center, and is characterized by exerting quick effects and a short treatment course. A total of 20 low-back and leg pain patients with lumbar disc herniation were treated with balanced acupuncture or body acupuncture. Central mechanisms of vaded acupunctures were compared using resting-state functional MRI. Patients from both groups received functional MRI before and after acupuncture. Functional connectivity in brain regions that were strongly associated with the bilatera amygdala was analyzed utilizing AFNI software. Visual analogue scale scores were greater in the balanced acupuncture group compared with the body acupuncture group. Function of the endogenous pain regulation network was enhanced in patients in the balanced acupuncture group, but was not changed in the body acupuncture group. This result indicates that the analgesic effects of body acupuncture do not work through the central nervous system. These data suggest that balanced acupuncture exerts analgesic effects on low-back and leg pain patients with lumbar disc herniation by regulating the function of the endogenous pain regulation network.

关键词： balanced acupuncture body acupuncture lumbar disc herniation functional connectivity amygdala low-back and leg pain pain acupuncture traditional Chinese medicine neural regeneration

Symmetric alteration of four knots of B-spline and NURBS surfaces

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第6期7卷 1084-1087页

作者： LI Ya-juan WANG Guo-zhao Institute of Computer Graphics and image Processing Department of Mathematics Zhejiang University Hangzhou 310027 China

Modifying the knots of a B-spline curve, the shape of the curve will be changed. In this paper, we present the effect of the symmetric alteration of four knots of the B-spline and the NURBS surfaces, i.e., symmetrical alteration of the knots of surface, the extended paths of points of the surface will converge to a point which should be expressed with several control points. This theory can be used in the constrained shape modification of B-spline and NURBS surfaces.

关键词： B-spline surface NURBS surface Knot modification Path