雍俊海
个性化签名
- 姓名:雍俊海
- 目前身份:
- 担任导师情况:
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学术头衔:
博士生导师, 教育部“新世纪优秀人才支持计划”入选者
- 职称:-
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学科领域:
计算机软件
- 研究兴趣:
雍俊海博士从1991年到2000年就读于清华大学计算机科学与技术系,获学士、硕士和博士学位,被评为清华大学优秀博士毕业生,博士论文被评为全国优秀博士论文。从2000年3月到2000年6月在香港科技大学计算机系担任访问研究员;从2000年11月到2002年9月在美国肯塔基大学计算机系做博士后;现为清华大学软件学院教师。
从2003年起在清华大学开设了《Java程序设计》、《计算机图形学》和《计算机动画的算法与技术》等课程,编写了教材《Java程序设计》,很受学生欢迎。根据清华大学2003-2004学年秋季学期教学评估结果,教学成绩在全校名列前茅,获得学生一致好评,在清华大学软件学院所有参评教师中取得教学成绩第一名。获得了清华大学软件学院教学工作优秀奖,大学生研究训练计划(SRT)优秀指导教师一等奖和清华之友——优秀教师奖。
参与或负责多个国家自然科学基金项目、国家863项目、973项目和美国自然科学基金项目。围绕商品化CAD软件系统的开发,近年来已经在《Computer-Aided Design》、《Computer Aided Geometric Design》和《计算机学报》等国内外学术刊物与会议上共录用和发表50多篇学术论文,其中在相关专业领域最好的国际期刊上有7篇论文,16篇论文被SCI收录,另有4篇尚待SCI收录。所发表论文共被他引36次,尤其是国际刊物《Computer-Aided Design》的主编多次正面引用其中部分论文。是5个重要国际会议委员会成员,是《Computer-Aided Design》和《IEEE Transactions on Visualization and Computer Graphics》等国际杂志和"The Pacific Conference on Computer Graphics and Applications"、"Geometric Modeling and Processing"等国际会议的审稿人,是清华大学先进工作者,并入选清华大学“骨干人才支持计划”和教育部“新世纪优秀人才支持计划”。
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主页访问
2615
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关注数
0
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成果阅读
467
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成果数
10
【期刊论文】Bisection algorithms for approximating quadratic Bezier curves by G1 arc splines
雍俊海, Jun-Hai Yong a, b, *, Shi-Min Hu a, Jia-Guang Sun a
Computer-Aided Design 32(2000)253-260,-0001,():
-1年11月30日
To describe the tool path of a CNC machine, it is often necessary to approximate curves by G1 arc splines with the number of arc segments as small as possible. Ahn et al. have proposed an iterative algorithm for approximating quadratic Be
CNC, Quadratic Bezier curves, Arc splines, Bisection algorithms
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35浏览
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1分享
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291下载
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引用
【期刊论文】CIM Algorithm for Approximating Three-Dimensional Polygonal Curves
雍俊海, YONG Junhai, HU Shimin, and SUN Jiaguang
J. Comput. Sci. & Technol.2001, 16 (6): 552~559,-0001,():
-1年11月30日
The polygonal approximation problem is a primary problem in computer graphics, pattern recognition, CAD/CAM, etc. In R2, the cone intersection method (CIM) is one of the most e
polygonal curve, CIM, LS-WMN, approximation, optimization
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36浏览
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84下载
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引用
【期刊论文】Unbalanced Hermite Interpolation with Tschirnhausen Cubics
雍俊海, Jun-Hai Yong, and Hua Su
J. Zhang, J.-H. He, and Y. Fu (Eds.): CIS 2004, LNCS 3314, pp. 1072-1078, 2004.,-0001,():
-1年11月30日
A method for constructing a cubic Pythagorean hodograph (PH) curve (called a Tschirnhausen cubic curve as well) satisfying unbalanced Hermite interpolation conditions is presented. The resultant curve interpolates two given end points, and has a given vector as the tangent vector at the starting point. The generation method is based on complex number calculation. Resultant curves are represented in a B
Hermite, Pythagorean hodograph, Absolute rotation number.,
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68浏览
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【期刊论文】Short Communication A note on approximation of discrete data by G1 arc splines
雍俊海, Jun-Hai Yong*, Shi-Min Hu, Jia-Guang Sun
Computer-Aided Design 31 (1999) 911-915,-0001,():
-1年11月30日
Meek and Walton discussed the approximation of discrete data by G1 arc splines in 1992. For a biarc from the start point A to the end point B, they assumed that the sum of two counterclockwise angles of the two arcs was equal to the sum of the counterclockwise angle from the start tangent vector to the vector B-A and that from the vector B-A to the terminal tangent vector. In this note, we show that the relation can be relaxed by the addition or subtraction of 2π.
Biarcs, Arc splines, Discrete-data approximation
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64浏览
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115下载
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【期刊论文】Dynamic highlight line generation for locally deforming NURBS surfaces
雍俊海, Jun-Hai Yong a, *, Fuhua (Frank) Cheng a, Yifan Chen b, Paul Stewart b, Kenjiro T. Miurac
Computer-Aided Design 35 (2003) 881-892,-0001,():
-1年11月30日
The highlight line model is a powerful tool in assessing the quality of a surface. Efficient highlight line generation is especially important for an interactive design environment. In this paper, a method for dynamic generation of highlight lines on a locally deforming NURBS surface is presented. The method generates frames of the deforming surface and the corresponding highlight lines by directly modifying the current highlight lines using a Taylor expansion technique, instead of going through a tracing process. The highlight lines computation process adopted here enables a unified distance surface to generate all highlight lines in the highlight line family. The computation process is facilitated by looking up pre-calculated information of the tessellation mesh and an indexing technique for the distance surface. The indexing technique is presented to determine when the highlight line model should be re-generated and, to facilitate the highlight line re-generation process. The new technique is suitable for interactive design environments and animation applications as the updating process takes only one subtraction and one vector inner product to get the new parameters for each new node.
NURBS surfaces, Highlight lines, Shape modification, Deformation
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30浏览
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118下载
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【期刊论文】Automatic G1 arc spline interpolation for closed point set
雍俊海, Xiao-Diao Chen a, b, Jun-Hai Yong a, *, Guo-Qin Zheng a, Jia-Guang Sun a
Computer-Aided Design 36 (2004) 1205-1218,-0001,():
-1年11月30日
A method for generating an interpolation closed G1 arc spline on a given closed point set is presented. For the odd case, i.e. when the number of the given points is odd, this paper disproves the traditional opinion that there is only one closed G1 arc spline interpolating the given points. In fact, the number of the resultant closed G1 arc splines fulfilling the interpolation condition for the odd case is exactly two. We provide an evaluation method based on the arc length as well such that the choice between those two arc splines is made automatically. For the even case, i.e. when the number of the given points is even, the points are automatically moved based on weight functions such that the interpolation condition for generating closed G1 arc splines is satisfied, and that the adjustment is small. And then, the G1 arc spline is constructed such that the radii of the arcs in the spline are close to each other. Examples are given to illustrate the method.
Arc spline, Circular arc interpolation, Closed point set, G1 continuity
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55浏览
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61下载
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【期刊论文】A new algorithm for Boolean operations on general polygons
雍俊海, Yu Peng a, Jun-Hai Yong b, Wei-Ming Dong a, Hui Zhang b, Jia-Guang Sun a, b
Computers & Graphics 29 (2005) 57-70,-0001,():
-1年11月30日
A new algorithm for Boolean operations on general planar polygons is presented. It is available for general planar polygons (manifold or non-manifold, with or without holes). Edges of the two general polygons are subdivided at the intersection points and touching points. Thus, the boundaryof the Boolean operation resultant polygon is made of some whole edges of the polygons after the subdivision process. We use the simplex theory to build the basic mathematical model of the new algorithm. The subordination problem between an edge and a polygon is reduced to a problem of determining whether a point is on some edges of some simplices or inside the simplices, and the associated simplicial chain of the resultant polygon is just an assembly of some simplices and their coefficients of the two polygons after the subdivision process. Examples show that the running time required bythe new algorithm is less than one-third of that bythe Rivero and Feito algorithm.
Curve, surface, solid, and object representations, Geometric algorithms, languages, and systems, Modeling packages, Computational geometry, Geometric modeling, Boolean operation, Polygon intersection
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70浏览
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85下载
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【期刊论文】Degree reduction of B-spline curves
雍俊海, Jun-Hai Yong a, *, Shi-MinHua, Jia-Guang Sun a, Xing-Yu Tan b
Computer Aided Geometric Design 18 (2001) 117-127,-0001,():
-1年11月30日
In this paper, we propose the generalized B divided difference, with which the (k−1)th derivative of B-spline curves of order k can be obtained directly without the need to compute the first (k−2) derivatives as before. Based on the generalized B divided difference, the necessary and sufficient condition for degree-reducible B-spline curves is presented. Algorithms for degree reduction of B-spline curves are proposed using the constrained optimization methods.
B-spline curve, Degenerate condition, Degree reduction, Generalized B divided difference, Constrained optimization
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35浏览
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73下载
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【期刊论文】Geometric Hermite curves with minimum strain energy☆
雍俊海, Jun-Hai Yong, Fuhua (Frank) Cheng*
Computer Aided Geometric Design 21 (2004) 28-301,-0001,():
-1年11月30日
The purpose of this paper is to provide yet another solution to a fundamental problem in computer aided geometric design, i.e., constructing a smooth curve satisfying given endpoint (position and tangent) conditions. A new class of curves, called optimized geometric Hermite (OGH) curves, is introduced. An OGH curve is defined by optimizing the magnitudes of the endpoint tangent vectors in the Hermite interpolation process so that the strain energy of the curve is a minimum. An OGH curve is not only mathematically smooth, i.e., with minimum strain energy, but also geometrically smooth, i.e., loop-, cusp- and fold-free if the geometric smoothness conditions and the tangent direction preserving conditions on the tangent angles are satisfied. If the given tangent vectors do not satisfy the tangent angle constraints, one can use a 2-segment or a 3-segment composite optimized geometric Hermite (COH) curve to meet the requirements. Two techniques for constructing 2-segment COH curves and five techniques for constructing 3-segment COH curves are presented. These techniques ensure automatic satisfaction of the tangent angle constraints for each OGH segment and, consequently,mathematical and geometric smoothness of each segment of the curve. The presented OGH and COH curves, combined with symmetry-based extension schemes, cover tangent angles of all possible cases. The new method has been compared with the high-accuracy Hermite interpolation method by de Boor et al. and the Pythagorean-hodograph (PH) curves by Farouki et al. While the other two methods both would generate unpleasant shapes in some cases, the new method generates satisfactory shapes in all the cases.
Hermite, Geometric continuity, Strain energy, Smoothness
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27浏览
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引用
雍俊海, 胡事民, 孙家广
计算机学报,2000,23(5):537~540,-0001,():
-1年11月30日
文中给出均匀B样条曲线退化的充要条件,证明了满足退化条件的k阶均匀B样条曲线可以表示为(k-1)阶均匀B样条曲线,并给出相应的表示方法。在此基础上,利用约束优化方法,提出均匀B样条曲线的一种降阶方法。而传统方法从升阶的反问题考虑降阶,要求被降阶的B样条曲线的所有节点都是多重节点,从而无法处理均匀B样条曲线。
B样条曲线, 退化, 降阶, 逼近
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