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Functional Limit Theorems for C-R Increments of k-Dimensional Brownian Motion in Holder Norm 被引量:11
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作者 Qicai Wei School fo Economics, Zhejiang University. Hangzhou 310028. P. R. China 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2000年第4期637-654,共18页
In this paper. based on large deviation formulas established in stronger topology generated by Hlder norm, we obtain the functional limit theorems for C-R increments of k-dimensional Brownian motion in Hlder norm
关键词 Large deviation formulas k-dimensional Brownian motion Functional limit theorems C-R increments Holder norm
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k-Dimensional hashing scheme for hard disk integrity verification in computer forensics
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作者 Zoe Lin JIANG Lucas Chi Kwong HUI +1 位作者 Siu Ming YIU Kam Pui CHOW 《Journal of Zhejiang University-Science C(Computers and Electronics)》 SCIE EI 2011年第10期809-818,共10页
Verifying the integrity of a hard disk is an important concern in computer forensics,as the law enforcement party needs to confirm that the data inside the hard disk have not been modified during the investigation.A t... Verifying the integrity of a hard disk is an important concern in computer forensics,as the law enforcement party needs to confirm that the data inside the hard disk have not been modified during the investigation.A typical approach is to compute a single chained hash value of all sectors in a specific order.However,this technique loses the integrity of all other sectors even if only one of the sectors becomes a bad sector occasionally or is modified intentionally.In this paper we propose a k-dimensional hashing scheme,kD for short,to distribute sectors into a kD space,and to calculate multiple hash values for sectors in k dimensions as integrity evidence.Since the integrity of the sectors can be verified depending on any hash value calculated using the sectors,the probability to verify the integrity of unchanged sectors can be high even with bad/modified sectors in the hard disk.We show how to efficiently implement this kD hashing scheme such that the storage of hash values can be reduced while increasing the chance of an unaffected sector to be verified successfully.Experimental results of a 3D scheme show that both the time for computing the hash values and the storage for the hash values are reasonable. 展开更多
关键词 Computer forensics Digital evidence Hard disk integrity k-dimensional hashing
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On the k-dimensional Piatetski-Shapiro prime number theorem
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作者 翟文广 《Science China Mathematics》 SCIE 1999年第11期1173-1183,共11页
Thek-dimensional Piatetski-Shapiro prime number problem fork?3 is studied. Let π(x 1 c 1,?,c k ) denote the number of primesp withp?x, $p = [n_1^{c_1 } ] = \cdots [n_k^{c_k } ]$ , where 1<c 1<?<c k are fixed... Thek-dimensional Piatetski-Shapiro prime number problem fork?3 is studied. Let π(x 1 c 1,?,c k ) denote the number of primesp withp?x, $p = [n_1^{c_1 } ] = \cdots [n_k^{c_k } ]$ , where 1<c 1<?<c k are fixed constants. It is proved that π(x;c 1,?,c k ) has an asymptotic formula ifc 1 ?1 +?+c k ?1 >k?k/(4k 2+2). 展开更多
关键词 k-dimensional Piatetski-Shapiro prime number theorem onential sum mptotic formula
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K-Dimension and Hlder Exponent for Bush Type Fractal Functions
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作者 王宏勇 《Journal of Southwest Jiaotong University(English Edition)》 2006年第4期400-403,共4页
Bush type fractal functions were defined by means of the expression of Cantor series of real numbers. The upper and lower bound estimates for the K-dimension of such functions were given. In a typical case, the fracta... Bush type fractal functions were defined by means of the expression of Cantor series of real numbers. The upper and lower bound estimates for the K-dimension of such functions were given. In a typical case, the fractal dimensional relations in which the K-dimension equals the box dimension and packing dimension were presented; moreover, the exact Holder exponent were obtained for such Bush type functions. 展开更多
关键词 Bush type function Fractal function k-dimension Holder exponent
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The Generalized Sine Theorem for Mixed Vertex Angle of Two Simplices and Applications
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作者 WANG Wen YANG Shi-guo QI Ji-bing 《Chinese Quarterly Journal of Mathematics》 2015年第2期190-198,共9页
Some related problems of two n-dimensional simplices which are on an(n- 1)-dimensional hypersphere are investigated and a sine theorem of the k-dimensional mixed vertex angles which are defined in this paper is given.... Some related problems of two n-dimensional simplices which are on an(n- 1)-dimensional hypersphere are investigated and a sine theorem of the k-dimensional mixed vertex angles which are defined in this paper is given. This result is a generalization of the sine theorem established. By using the generalized sine theorem, we present some new interesting geometric inequalities involving the k-dimensional vertex angles of each n-simplex and the k-dimensional mixed vertex angle of two n-simplices. These results can improve some recent results. 展开更多
关键词 simplex k-dimensional vertex angle k-dimensional mixed vertex angle the sine theorem geometric inequalities
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基于改进随机抽样一致的点云分割算法 被引量:13
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作者 赵夫群 马玉 戴翀 《科学技术与工程》 北大核心 2021年第22期9455-9460,共6页
随着三维点云数据模型在三维建模、测绘、智能城市以及机器视觉等领域的应用,点云数据处理也成为一个研究热点。点云分割就是将三维空间中点云通过一系列算法,将散乱的点云数据划分成更为连贯的子集的过程,可以为后续的数据分析提供数... 随着三维点云数据模型在三维建模、测绘、智能城市以及机器视觉等领域的应用,点云数据处理也成为一个研究热点。点云分割就是将三维空间中点云通过一系列算法,将散乱的点云数据划分成更为连贯的子集的过程,可以为后续的数据分析提供数据基础。针对随机抽样一致算法(random sample consensus,RANSAC)对杂乱、无规则点云数据分割效果不佳的问题,提出一种改进的RANSAC点云分割算法。该算法通过构建Kd(K-dimensional)树,利用半径空间密度重新定义初始点的选取方式,进行多次迭代来剔除无特征点,在实现点云分割的同时可以有效去除噪声点;此外,该算法重新设定判断准则,优化面片合并,可以实现点云的精确分割。实验通过对散乱点云数据进行分割,结果表明该改进RANSAC算法的点云特征提取数据量较大,面片分割的准确性较高,是一种有效的点云分割算法。 展开更多
关键词 点云分割 随机抽样一致 k-dimensional(Kd)树 半径空间密度 面片合并
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Simulating unmanned aerial vehicle flight control and collision detection 被引量:1
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作者 Mengtian Liu Meng Gai Shunnan Lai 《Visual Computing for Industry,Biomedicine,and Art》 2019年第1期38-44,共7页
An unmanned aerial vehicle(UAV)is a small,fast aircraft with many useful features.It is widely used in military reconnaissance,aerial photography,searches,and other fields;it also has very good practical-application a... An unmanned aerial vehicle(UAV)is a small,fast aircraft with many useful features.It is widely used in military reconnaissance,aerial photography,searches,and other fields;it also has very good practical-application and development prospects.Since the UAV’s flight orientation is easily changeable,its orientation and flight path are difficult to control,leading to its high damage rate.Therefore,UAV flight-control technology has become the focus of attention.This study focuses on simulating a UAV’s flight and orientation control,and detecting collisions between a UAV and objects in a complex virtual environment.The proportional-integral-derivative control algorithm is used to control the orientation and position of the UAV in a virtual environment.A version of the bounding-box method that combines a grid with a k-dimensional tree is adopted in this paper,to improve the system performance and accelerate the collision-detection process.This provides a practical method for future studies on UAV flight position and orientation control,collision detection,etc. 展开更多
关键词 Unmanned aerial vehicle Proportional-integral-derivative control algorithm Orientation control Position control GRID k-dimensional tree Collision detection
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FUNCTIONAL MODULUS OF CONTINUITY FOR BROWNIAN MOTION IN HLDER NORM 被引量:10
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作者 WEI QICAI School of Economics, Zhejiang University, Hangzhou 310028, China. 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2001年第2期223-232,共10页
The author establishes a large deviation for k-dimensional Brownian motion B in stronger topology, by which the functional modulus of continuity for B in Holder norm can be obtained.
关键词 Large deviations Functional modulus of continuity k-dimensional Brownian motion Holder norm
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