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一种基于GPU加速的三维分形实时渲染方法 被引量:6
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作者 陈倩 潘中良 《激光杂志》 北大核心 2016年第11期136-140,共5页
绘制高质量三维分形图所需的计算量往往很大,难以达到实时的要求。研究了一种绘制三维分形的通用方法,即基于光线跟踪的距离估计算法。该算法非常适合在GPU上实现,利用GPU强大的并行处理能力,使三维分形的绘制速度显著提高。大量实验结... 绘制高质量三维分形图所需的计算量往往很大,难以达到实时的要求。研究了一种绘制三维分形的通用方法,即基于光线跟踪的距离估计算法。该算法非常适合在GPU上实现,利用GPU强大的并行处理能力,使三维分形的绘制速度显著提高。大量实验结果表明,在屏幕分辨率为1280x720时绝大部分三维分形图都已达到了实时绘制的要求。GPU与CPU的性能对比表明,即使在CPU最快的情况下耗时也是GPU的158倍,由此可见应用GPU的巨大优势。还验证了距离估计算法的通用性,对于不同类型的分形,如逃逸时间算法的分形、迭代函数系统的分形以及分形地形都可以适用。 展开更多
关键词 三维分形 GPU 实时渲染 距离估计算法 OPENGL
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A Robust Collaborative Recommendation Algorithm Based on k-distance and Tukey M-estimator 被引量:6
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作者 YI Huawei ZHANG Fuzhi LAN Jie 《China Communications》 SCIE CSCD 2014年第9期112-123,共12页
The existing collaborative recommendation algorithms have lower robustness against shilling attacks.With this problem in mind,in this paper we propose a robust collaborative recommendation algorithm based on k-distanc... The existing collaborative recommendation algorithms have lower robustness against shilling attacks.With this problem in mind,in this paper we propose a robust collaborative recommendation algorithm based on k-distance and Tukey M-estimator.Firstly,we propose a k-distancebased method to compute user suspicion degree(USD).The reliable neighbor model can be constructed through incorporating the user suspicion degree into user neighbor model.The influence of attack profiles on the recommendation results is reduced through adjusting similarities among users.Then,Tukey M-estimator is introduced to construct robust matrix factorization model,which can realize the robust estimation of user feature matrix and item feature matrix and reduce the influence of attack profiles on item feature matrix.Finally,a robust collaborative recommendation algorithm is devised by combining the reliable neighbor model and robust matrix factorization model.Experimental results show that the proposed algorithm outperforms the existing methods in terms of both recommendation accuracy and robustness. 展开更多
关键词 shilling attacks robust collaborative recommendation matrix factori-zation k-distance Tukey M-estimator
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A new fast algorithm for computing the distance between two disjoint convex polygons based on Voronoi diagram
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作者 YANG Cheng-lei QI Meng +2 位作者 MENG Xiang-xu LI Xue-qing WANG Jia-ye 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第9期1522-1529,共8页
Computing the distance between two convex polygons is often a basic step to the algorithms of collision detection and path planning. Now, the lowest time complexity algorithm takes O(logm+logn) time to compute the min... Computing the distance between two convex polygons is often a basic step to the algorithms of collision detection and path planning. Now, the lowest time complexity algorithm takes O(logm+logn) time to compute the minimum distance between two disjoint convex polygons P and Q, where n and m are the number of the polygons’ edges respectively. This paper discusses the location relations of outer Voronoi diagrams of two disjoint convex polygons P and Q, and presents a new O(logm+logn) algo- rithm to compute the minimum distance between P and Q. The algorithm is simple and easy to implement, and does not need any preprocessing and extra data structures. 展开更多
关键词 Computational geometry POLYGON Voronoi diagram Distance computation
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Novel Algorithm for Estimating the Distance of Open-Conductor Faults in HV Transmission Lines
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作者 Mahmoud Gilany Ahmed Al-Kandari Bahaa Hassan 《Journal of Energy and Power Engineering》 2012年第8期1301-1307,共7页
This paper presents an ANN (artificial neural networks)-based technique for improving the performance of distance relays against open-circuit faults in transmission networks. The technique utilizes the small capacit... This paper presents an ANN (artificial neural networks)-based technique for improving the performance of distance relays against open-circuit faults in transmission networks. The technique utilizes the small capacitive current measured in the open-phase plus the currents in the two healthy phases in calculating the open-circuit fault distance. The results obtained show that a distance relay with the proposed scheme will not only be able to detect the open-conductor condition in HVTL (high voltage transmission line) but also to locate the place of this fault regardless the value of the pre-fault current loading. There is no need for especial communication schemes since the existing media could work properly for the needs of the proposed technique. 展开更多
关键词 Distance relay open-conductor ANN transmission networks fault location.
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