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1.
针对利用匿名框实现的兴趣点K近邻(KNN)查询带来的通信开销大、时延长等问题,提出了基于单一兴趣点Voronoi图划分和四叉树层次化组织的KNN查询方法。该方法根据兴趣点层次信息有针对性的构造查询匿名框用来获取详细查询信息,在保护位置隐私的同时,降低了查询通信开销,同时注入虚假查询保护了用户的真实查询内容隐私。最后分别采用模拟地理数据和真实地理数据进行理论分析和有效性验证。 相似文献
2.
Homotopy methods are known to be effective methods for finding dc operating points of nonlinear circuits with the theoretical guarantee of global convergence. There are several types of homotopy methods; as one of the efficient methods for solving bipolar circuits, the variable gain homotopy (VGH) method is well-known. However, in the conventional VGH method, the initial point is sometimes far from the solution because it is given as a solution of a diode circuit. In this brief, we propose an efficient VGH method using the SPICE-oriented approach. The proposed method can be easily implemented on SPICE without programming, although we do not know the homotopy method well. Moreover, since we can use a good initial point, the path following tends to become smooth and efficient. 相似文献
3.
在分析全串行和全并行GF(2k)域乘法的基本原理基础上提出了一种适合于任意GF(2k)域的乘法器UHGM(Unified Hybrid Galois Field Multiplier).它为当前特别重要的k为素数的GF(2k)域乘法,提供了一种高效的实现方法.该乘法器具有结构规整、模块化好的特点,特别适合于VLSI实现,同时这种结构具有粗粒度的面积和速度的可伸缩性,方便了在大范围内进行实现面积和速度的权衡.最后给出了GF(2163)域上乘法器的ASIC综合的结果. 相似文献
4.
文中提出GF(q)上计算周期为2p n的序列k-错线性复杂度的一个快速算法(这里p和q是素数,并且q是一个模p 2的本原根).新算法的计算复杂度为O(N)(这里N是序列的周期). 相似文献
5.
文章针对10阶LSF参数求解,提出一种基于牛顿迭代法的有效算法,并通过实验比较了该算法和经典的Kabal搜索算法的运算量、精度。该算法避免了多项武降次,计算量又远远小于经典的搜索算法.适于用大规模集成电路实现,而且可以推广应用干求解更高阶LSF参数。 相似文献
6.
构建系统发生树是研究物种起源和演化的重要手段.本文基于KEGG(Kyoto Encyclopedia of Genes and Genomes)代谢路径,引入图论的"核"概念,提出一种构建系统发生树的方法.首先解决在无数据丢失前提下,代谢路径数据的提取和表示问题,其次将不同代谢路径的相似度定义为图的核部分与非核部分各自匹配程度的加权之和,利用距离矩阵构建物种间的系统发生树.通过大量试验数据和NCBI(National Center for Biotechnology Information)分类法进行比较,验证了本文方法的有效性. 相似文献
7.
1 发送安全的匿名邮件 有人认为,设置电子邮件地址时,只要输入一个错误的地址或干脆不填,就能发送匿名邮件,其实这并不能真正作到匿名。因为别人可以从你的邮件信头部分看到发信的时间,使用的邮件服务器等信息。如果要实现保护重要电子邮件而不被人截获以及避免自己的电子邮件地址被人当作袭击目标,可利用匿名邮件转发器,真正实现匿名邮件发送。remailer@replay.com,remailer@anon.efga.org,mix- 相似文献
8.
Black-burst based multi-hop broadcast protocols are effective means to disseminate Emergency messages (EMs) in Vehicular ad hoc networks (VANETs). However, Clear to broadcast (CTB) collision will happen and reduce propagation speed. Aiming at this problem, we propose a Black-burst and multi-channel based multi-hop broadcast (BMMB) protocol. Vehicles with multiple antennas can transmit and sense black-burst at different channels simultaneously based on multi-channel technol-ogy. Compared with existing black-burst based methods, BMMB shortens the iterative procedure to find out the optimal segment. Only one relay vehicle can be rapidly se-lected within the optimal segment without CTB collision. BMMB enables alternative broadcast methods, i.e., uni-directional broadcast and multi-directional broadcast for straight roads and intersections respectively. Theoretical analysis is done for performance evaluation of BMMB, and simulation results demonstrate that BMMB performs better in terms of average one-hop delay and propagation speed. 相似文献
9.
The purpose of this paper is to introduce a new method for solving the inverse problem of locating ischemic regions in the heart. The electrical activity in the human heart is modeled by the bidomain equations, which can be expanded to compute the potentials on the body surface. The associated inverse problem is to use ECG recordings to gain information about ischemias. We propose an algorithm for doing this, combining the level set method with a simpler minimization problem. Instead of trying to determine the shape, as in the level set method, we simply make the approximation that the ischemia is spherical. The effects of ischemia on the electrical attributes of heart tissue are examined. The new method is tested with computer simulations on synthetic body surface potential maps (BSPMs) in a realistic geometry, using realistic values for the parameters. It is shown to be, in some respects, superior to the level set approach and may be a step toward a practical algorithm useful in medical diagnostics. 相似文献
10.
An efficient finite element method (FEM.) in waveguide analysis is described. The method rises Hermitian polynomials to interpolate the field compohent (E/sub z/ or H/sub z/) and some of its derivatives at the nodal points, rather than the field components, as in the Lagrangian interpolation case. Element matrices, for a standard triangle, are given for third- and fifth-degree Hermitian polynomials. The appropriate transformations that relate the element matrices of a general triangle to the standard triangle element have been derived. Compared to the broadly used Lagrangian interpolation FEM, the Hermitian FEM has the following advantages 1) a significant reduction of the matrix order needed to compute the eigenvalues and eigenfunction; 2) smooth axial components (E/sub z/ or H/sub z/) and continuous transverse field components; 3) low-cost refinement of the mesh near nonconvex corners of the waveguide. These advantages are illustrated by comparing the FEM, with Hermitian polynomials solution, to other solutions for rectangular and ridged waveguides. 相似文献
12.
Satellite image segmentation has gotten bunches of consideration of late because of the accessibility of commented on high-goals image informational indexes caught by the last age of satellites. The issue of fragmenting a satellite image can be characterized as ordering (or marking) every pixel of the image as indicated by various classes, for example, structures, streets, water, etc. In this paper centered to build up a satellite image segmenting process by utilizing distinctive optimization methods. The work is prepared dependent on three stages that are RGB change, preprocessing, and division. At first the database images are assembled from the database at that point select the blue band images by performing RGB change. To improve the differentiation and furthermore decreasing the commotion of these chose blue band images, Hopfield neural network (HNN) is utilized. After image upgrade, the images are fragmented dependent on fuzzy C means (FCM) clustering method. The images are clustered and segmented in the way of optimizing the centroid in FCM utilizing oppositional crow search algorithm. The exhibition of the proposed framework is investigated dependent on the presentation measurements, for example, affectability, particularity and accuracy. From the outcomes, the proposed strategy diminished the computational time by expanding the accuracy of 98.3% with HNN system. 相似文献
13.
We present a new method to determine the contribution of the IF-amplifier chain to the overall noise performance of an SE-based receiver. Using simulated I-V and IF power characteristics, we show that the standard method used to date to evaluate the IF noise can underestimate the contribution because of non-negligible curvature in the post-gap SIS I-V characteristic. We demonstrate that the new method is not susceptible to the post-gap curvature, and discuss its benefits and limitations to the accurate and precise evaluation of IF noise contributions. 相似文献
14.
在图像处理系统中,通过采集设备获得的图像如彩色扫描文档不可避免地会出现倾斜现象,虽然文档图像处理技术已经取得很多进展,但是,对于倾斜图像的矫正还存在困难.本文根据图像的结构特征 ,给出了基于Canny边缘检测和Radon变换相结合的算法,根据Radon变换取得的倾斜角度进行图像的倾斜矫正.实验表明,算法对彩色图像进行自动矫正是准确、高效的. 相似文献
15.
In this paper, an efficient method for iris feature extraction using the Pulse coupled neural network (PCNN) is proposed. In order to segment out those iris features such as crypts, furrows, spots in the iris image, the PCNN network is introduced. And the output pulse image produced by PCNN is chosen as the iris codes. At last the performance of the proposed approach is demonstrated with experiments. Encouraging results demonstrated that the proposed iris features extraction method is able to produce a representation that allows for discriminating a large number of iris patterns. 相似文献
16.
当底层数据的容量以及轮廓推荐指令个数增大时,轮廓推荐的时间代价将呈指数级增长,从而严重影响其推荐效率。为此,基于超对等分布式网络(SPA),该文提出预存储w个轮廓快照来高效处理系统中u个轮廓推荐指令的分布式网络轮廓推荐算法(EMSRDN)。EMSRDN算法充分考虑SPA网络的数据存储和通信特性,利用map/reduce分布式计算模型,通过初始快照集启发式构造来快速产生最优w个轮廓快照。理论分析和仿真实验表明,该算法具有有效性和实用性。 相似文献
17.
A nonlinear circuit model of the GaAs MESFET is developed by extracting circuit parameters from dc and small-signal RF measurements in a systematic manner. The circuit model is then analyzed by an efficient algorithm called the modified multiple-reflection method. For the first time, this method is applied to MESFET circuit analysis. Compared with the original multiple-reflection method, the modified multiple-reflection method shows a dramatic increase in convergence speed. The validity of the nonlinear MESFET model is confirmed by comparing the simulation results with experimental data. 相似文献
18.
Cloud computing and storage services allow clients to move their data center and applications to centralized large data centers and thus avoid the burden of local data storage and maintenance. However, this poses new challenges related to creating secure and reliable data storage over unreliable service providers. In this study, we address the problem of ensuring the integrity of data storage in cloud computing. In particular, we consider methods for reducing the burden of generating a constant amount of metadata at the client side. By exploiting some good attributes of the bilinear group, we can devise a simple and efficient audit service for public verification of untrusted and outsourced storage, which can be important for achieving widespread deployment of cloud computing. Whereas many prior studies on ensuring remote data integrity did not consider the burden of generating verification metadata at the client side, the objective of this study is to resolve this issue. Moreover, our scheme also supports data dynamics and public verifiability. Extensive security and performance analysis shows that the proposed scheme is highly efficient and provably secure. 相似文献
19.
Wireless Personal Communications - At present the low cost, low power and collaborative feature of Wireless Sensor Network (WSN) is becoming a popular communication technology in smart grid... 相似文献
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