一种减轻显式组播路由节点负载的策略

本文基于显式组播（Explicit Multicast）机制和遗传算法的思想，提出了一种通过减少组播组中存放转发信息的路由节点数量来减轻路由路径负担的策略。通过算法描述和分析及实验仿真，此方案可以有效地节省网络资源。     

An image pixel based variational model for histogram equalization

In this paper, we develop an image pixel based histogram equalization model for image contrast enhancement. The approach is to propose a variational model containing an energy functional to adjust the pixel values of an input image directly so that the resulting histogram can be redistributed to be uniform. This idea is different from existing histogram equalization algorithms where a histogram based on the input image is constructed, a mapping is determined to output a uniform histogram and then the pixel values of the input image are adjusted based on the mapping. In the variational model, a mean brightness term is incorporated to preserve the brightness of the input image, and a geometry constraint can also be added to keep the geometry structure of the input image. Theoretically, the existence of the minimizer of the proposed model, and the convergence of the proposed algorithm are given. Experimental results are reported to demonstrate that the performance of the proposed model are competitive with the other testing histogram equalization methods for several testing images.     

Fast computation of generic bivariate resultants

We prove that the resultant of two “sufficiently generic” bivariate polynomials over a finite field can be computed in quasi-linear expected time, using a randomized algorithm of Las Vegas type. A similar complexity bound is proved for the computation of the lexicographical Gröbner basis for the ideal generated by the two polynomials.     

A statistical model for global optimization by means of select and clone

A statistical model tor giobai optimization is constructed generalizing some properties ofthe Wiener process to the multidimensional case. A new approach, which is similar to the Branch and Bound approach, is proposed to the construction of algorithms based on statistical models. A two dimensional version of the algorithm is implemented, and test results are presented     

基于改进KNN算法的AVS到H.264/AVC 快速转码方法

尽管音视频编码标准(Audio and Video Coding Standard,AVS)的编码性能可以与H.264相媲美,但是H.264的应用范围更加广泛,因此视频由AVS标准转码成H.264标准具有很大的应用前景.目前,主流的转码方法是将AVS的分块模式与H.264的分块模式映射的方式降低转码复杂度,但是技术之间的差异导致这两种标准之间的分块模式并不是一一映射的关系,因此会导致编码效率大幅度降低.提出一种基于改进KNN(K最邻近节点)算法的AVS到H.264/AVC快速转码方法.充分利用了AVS码流中的各种信息,通过改进的KNN算法建立了中间信息和H.264分块模式之间的映射模型.根据AVS中运动矢量信息的差异自适应确定H.264可能的分块模式,实验结果表明上述问题得到有效解决,该算法在保证H.264编码效率的前提下大幅降低了转码复杂度.     

多元LDPC码列分层DBC译码算法

针对多元LDPC码扩展最小和（Extended Min Sum,EMS）译码算法收敛速度慢、运算复杂度高的问题,提出一种多元LDPC码列分层动态检泡（Dynamic Bubble-Check,DBC）译码算法。首先对变量节点按不同列重进行分层处理,译码时率先更新列重较大分层的变量节点消息,不同层之间采用串行方式进行消息传递,通过并串结合的方式降低译码迭代次数。在校验节点消息更新过程中,采用动态检泡方法减少EMS算法中的运算量,降低算法复杂度。仿真结果表明,在几乎不损失性能的前提下,该算法的平均最大迭代次数仅为EMS译码算法的50%,复杂度降低为EMS算法的50%。     

深水多波束测深系统脉冲压缩实时算法

线性调频信号是大时宽带宽积信号,通过脉冲压缩可提高探测距离和分辨率,已在深水多波束测深系统中得到广泛应用。针对深水多波束测深系统中脉冲压缩运算量大的问题,提出了一种基于分组的脉冲压缩实时算法。该算法对需要进行脉冲压缩的波束进行分组,每个节拍只计算一组波束,可大幅减少深水多波束测深系统脉冲压缩的运算时间,节省了处理器资源。该算法已成功应用于某深水多波束测深系统,经多次海试证明,工作稳定可靠。     

Pseudo‐3D RSSI‐based WSN localization algorithm using linear regression

Receiver Strength Signal Indication based Wireless Sensor Networks offer a cheap solution for location‐aware applications. For a final breakthrough these systems need fast deployment and easy auto‐configuration. In this study, we use the real‐life iMinds test bed to expand a two‐dimensional localization algorithm to the pseudo third dimension with very low additional computational time. Our experiments show that this fast three‐dimensional algorithm has no outliers and avoids manual calibration. Our algorithm has lower position errors than a maximum likelihood algorithm with a mean square error cost function. Furthermore, with non‐parametric statistical tests, we show that our previously designed two‐dimensional preprocessing performs equally well in pseudo‐three dimensions: the preprocessing reduces the position error in a statistically significant way.Copyright © 2013 John Wiley & Sons, Ltd.     

红黑排序混合算法收敛速度分析

The algorithm of applying the block Gauss elimination to the Red-Black or-dering matrix to reduce the order of the system then solve the reduced system byiterative methods is called Hybrid Red-Black Ordering algorithm.In this paper,we discuss the convergence rate of the hybrid methods combined with JACOBI,CG,GMRES(m).Theoretical analysis shows that without preconditioner thesethree hybrid methods converge about 2 times as fast as the corresponding natural ordering methods.For the case that all the eigenvalues is near the real axis, the GMRES(m) algorithm converges about 3 times faster than the natural ordering GMRES(m).Various numerical experiments are presented.For large scale prob-lem with preconditioners, numerical experiments show that the GMRES(m) hybrid methods converge from about 3 times to even 5 times as fast as the natural order-ing methods and the computing time is reduced to about 1/3 even 1/6 of that of the natural ordering methods.     

基于无线数据业务智能优化系统算法的研究与应用

针对业界GPRS/EDGE无线数据优化方法、算法不完善,工作效率低的问题,广西联通通过长期研究建立了一套优化经验方法和较适合现网的参数配置、算法,并将这套方法、算法应用到自主开发的无线数据业务智能优化系统中,使系统实现自动采集分析数据、自动提供优化方案、自动执行优化方案、自动生成优化报告功能,使无线数据业务优化工作朝着智能化方向迈进。