Fast recursive algorithm for two-dimensional Tsallis entropy thresholding method

Recently, a two-dimensional (2-D) Tsallis entropy thresholding method has been proposed as a new method for image segmentation. But the computation complexity of 2-D Tsallis entropy is very large and becomes an obstacle to real time image processing systems. A fast recursive algorithm for 2-D Tsallis entropy thresholding is proposed. The key variables involved in calculating 2-D Tsallis entropy are written in recursive form. Thus, many repeating calculations are avoided and the computation complexity reduces to O(L2) from O(L4). The effectiveness of the proposed algorithm is illustrated by experimental results.     

一种新的群集智能优化及其改进研究

研究一种新的群集智能优化算法—自由搜索(FS)算法。提出了该算法的改进策略,实时调整个体的邻域搜索半径和精英保留。用典型测试函数对FS的改进算法和微粒群算法(PSO)进行对比实验,实验结果验证了算法的正确性和高效性。该算法不仅在收敛精度、收敛速度方面较PSO算法有明显的提高,而且全局搜索能力更强。     

空时二维线性预测谱估计算法

线性预测是时间序列分析中常用方法,针对传统一维线性预测谱估计算法只能估计信号源角度或信号频率问题,提出空时二维线性预测算法。采取对空时二维阵列接收到的数据进行数据抽取和排列,和对数据协方差矩阵进行重新构造的方法,求取空时二维线性预测权值并进行谱峰搜索。重点分析了空时二维的前向预测、后向预测和双向预测算法的原理,着重研究了构造的空时二维线性预测协方差矩阵的数据结构,讨论了前向、后向和双向预测的相互关系以及二维与一维的关系,并与空时二维最小方差算法、空时二维多重信号分类(multiple signal classification, MUSIC)算法进行了对比与分析。理论分析与仿真表明,一维空域、一维时域算法的前向、后向和双向预测为空时二维预测算法的特例,同时空时二维预测算法不仅克服了空时二维最小方差算法、空时二维MUSIC算法不能解相干信号源的缺点,还具有很好的测向测频能力。     

二维不可分滤波器级联小波的图像去噪算法

针对目前数字图像处理中的图像多方向信息提取问题,提出了一种利用二维不可分滤波器提取多方向信息的小渡域图像去噪算法.该算法首先设计两个具有方向性的二维不可分滤波嚣,然后通过小波变换简单有效地提取了图像六个方向上的方向信息,最后用带有椭圆型方向窗的小波域局部阈值维纳滤波算法对含噪图像进行去噪.通过仿真实验表明,图像多方向信息的提取简单有效,且去噪效果相比于已有的基于二维可分小波的图像去噪算法有了显著的提高.     

VCP协议公平性算法的仿真分析与改进研究

变结构控制协议(variable structure congestion control protocol, VCP)是一种高带宽时延网络环境下良好的拥塞控制机制,但当各数据流之间往返时延差异较大时,系统表现出不公平。结合NS2仿真实验,分析了在VCP同步数据流和异步数据流作用下系统的公平性。建立了VCP数据流稳态吞吐量的一个简单模型,指出了数据流稳态吞吐量与其公平性算法乘减参数的实际均值有关。通过在端系统自适应调整公平性算法加性参数的权值,有效提高了异步数据流作用下系统的公平性。最后通过仿真实验验证了改进算法的有效性。     

基于BP-PID控制的载波频率准确度提高算法

转发式卫星导航系统是我国自主研发的一种新型卫星导航体制和系统,但由于受到上行链路多普勒与卫星转发器的影响,系统载波频率准确度量级为10-8,达不到系统载波频率的使用精度.为解决此问题,详细分析了恶化转发式卫星导航系统载波频率的影响因素,通过测量分析得到上行载波频率的预偏量,采用基于反向传播神经网络的比例积分微分控制方法...     

New design and analysis of finite difference domain decomposition algorithm for the two-dimensional heat equation

<正> It is presented in this paper that the new design and its analysis of finite difference domaindecomposition algorithms for the two-dimensional heat equation,and the numerical results have shownthe stability and accuracy of the algorithms,where Saul'yev asymmetric schemes have been used atthe interface points.The Algorithm Ⅱ in this paper has further extended those developed by Dawsonand the others,Zhang and Shen.     

Modified wavelet filtering algorithm applied to gyro servo technology for the improvement of test-precision

In order to improve the measurement-precision of the gyro,the gyro experiment is completed based on gyro servo technology.The error sources of gyro servo technology are analyzed in the process of measurement,and the impact of these error sources on measurement is evaluated.To eliminate interference signal existing in the sampled data of the measurement,a modified wavelet threshold filtering method is presented.The results of the simulation and measurement show that the estimation-precision of the proposed method is improvement remarkably compared with the fast Fourier transform method,and the calculation work is reduced compared with the conventional wavelet threshold filtering methods,furthermore,the phenomenon of a common threshold of killing is solved thoroughly.     

蚁群算法的全局收敛性研究及改进

针对蚁群算法(ACA)寻优性质优良,但搜索时间长、收敛速度慢、易限于局部最优解,从而使其进一步推广应用受到局限的问题,对算法的全局收敛性进行了深入的理论研究,并从改善全局收敛性的角度对算法作了一系列改进,最后对Bayes29这一典型的TSP问题进行了仿真实验。实验结果证明,改进后的蚁群算法具有很好的全局收敛性能。这为蚁群算法的进一步理论研究打下了很好的基础,对其在各优化领域中的推广应用具有重要意义。     

一种基于rough set的多用户检测算法

将粗糙集(RoughSet)与多用户检测相结合,提出一种新型的多用户检测算法。粗糙集可以在期望用户的特征波形、定时、时延和多径等信息未知时,对接收数据进行约简,提取出接收数据与期望用户符号之间的规则,从而进行有效的分类,可以较好地应用于复杂的信道环境。理论分析和仿真结果表明了该方法的有效性和实用性。     

无定向拓扑连接的并行遗传算法及其变异算子改进

为解决巨量优化问题,在Internet平台下为并行遗传算法提出一个新的拓扑结构———无定向拓扑连接。该拓扑连接既允许驻留子种群的计算机节点中途退出,又允许新的计算机节点随时参与进化,增强了算法的鲁棒性和容错性能。针对传统浮点变异算子的不足,提出一种新的二元浮点补码变异算子,讨论了它在克服早熟收敛方面的作用。实验表明,提出的算法能显著提高寻优质量,节约寻优时间;新的变异算子能有效阻止遗传算法陷入局部极值,进一步提高了遗传算法的寻优能力。     

一种求解二阶锥规划问题的新算法

为了提高求解二阶锥规划问题的效率,提出一种新的求解二阶锥规划问题的非单调信赖域算法.基于Fischer-Burmeister光滑函数,对二阶锥规划问题的最优性条件进行转化,得到与其等价的无约束优化问题的非线性可微的光滑方程组,构造信赖域子问题,利用非单调信赖域算法求解.算法在求解信赖域子问题时,提出了一个新的自适应选取信赖域半径机制,搜索到全局最优解.数值实验结果表明,该算法运行速度快、迭代次数少,比内点算法和不可行内点算法优越.     

A simplified decoding algorithm for multi-CRC polar codes

Polar codes represent one of the major breakthroughs in 5G standard,and have been proven to be able to achieve the symmetric capacity of binary-input discrete memoryless channels using the successive cancellation list(SCL)decoding algorithm.However,the SCL algorithm suffers from a large amount of memory overhead.This paper proposes an adaptive simplified decoding algorithm for multiple cyclic redundancy check(CRC)polar codes.Simulation results show that the proposed method can reduce the decoding complexity and memory space.It can also acquire the performance gain in the low signal to noise ratio region.     

A second order Mehrotra-type predictor-corrector algorithm for semidefinite optimization

Mehrotra-type predictor-corrector algorithm is one of the most effective primal-dual interior-point methods.This paper presents an extension of the recent variant of second order Mehrotra-type predictor-corrector algorithm that was proposed by Salahi,et al.（2006） for linear optimization.Based on the NT direction as Newton search direction,it is shown that the iteration-complexity bound of the algorithm for semidefinite optimization is O(n^3/2 log X⁰·S⁰/ε),which is similar to that of the corresponding algorithm for linear optimization.     

A smoothing conjugate gradient algorithm for nonlinear complementarity problems

A PRP-type smoothing conjugate gradient method for solving large scale nonlinear complementarity problems （NCP（F）） is proposed. At each iteration, two Armijo line searches are performed, which guarantees the positive property of the smoothing parameter and minimizes the merit function formed by Fischer-Burmeister function, respectively. Global convergence is studied when F：R^n→R^n is a continuously differentiable P0 ＋ R0 function. Numerical results show that the method is efficient.     

目标分配的蚁群-模拟退火算法及其改进

直升机编队的对地攻击过程中,目标分配是实现作战任务的重要条件。确定了直升机目标分配的优势度计算方法以及目标分配的原则。利用蚁群-模拟退火算法实现了直升机对地攻击的目标分配过程,并针对分配过程中,采用综合优势度最大来确定最优路径所出现的不足对算法进行了改进,即根据信息素的积累量来确定最优路径,能够综合考虑信息素浓度与优势度的影响,避免了为达到全局最大优势度而出现的个体分配效益不好以及收敛缓慢的情况。实验结果表明,改进的算法效率更高,收敛的速度较之前更快,分配结果更趋合理。     

A selfish routing based network improvement problem

This paper considers a selfish routing based network improvement problem, in which the authors would like to find a modified latency function that results in a new Nash equilibrium flow satisfying all traffic demands subject to the target capacity, while the total modification cost on edge latency is minimized. By using the reduction from the 3-Satisfiability (3-SAT) problem to our problem, the authors show that this problem is strongly NP-hard, even for the single commodity network.     

改进的离散化方法在二维电磁散射中的应用

电磁散射问题的数值解通常采用积分方程结合矩量法求解,而阻抗矩阵元素的计算是影响矩量法计算精度和效率的重要因素之一。对于电大尺寸目标,要保持计算精度,传统矩量法需成倍细化网格剖分,这将耗费大量的计算机资源,并且计算效率大为下降。针对二维散射情况,引入二级近似方法来生成阻抗矩阵,将计算结果与传统矩量法及数值积分进行了比较,结果表明:该方法在同等计算精度的前提下,所需未知量数大大减少。     

A design for environment methodology for evaluation and improvement of derivative consumer electronic product development

Increasing environmental awareness and stringent environmental regulations have motivated many companies to incorporate ecodesign into product development.To assist companies to address the challenge,this research presents a design for environment(DfE) methodology to evaluate and improve derivative consumer electronic product development using a back-propagation neural network(BPNN) model and a technique for order preference by similarity to ideal solution(TOPSIS) method.Based on use of a BPNN,the life cycle assessment(LCA) models are developed to estimate quantities of hazardous chemical substances and energy consumption for a derivative consumer electronic product throughout the product life cycle.A performance evaluation and improvement model for DfE is then devised based on the TOPSIS method to analyze the ecodesign performance and provide concrete improvement strategies.With the aforementioned analysis of environmental performance,an enterprise can profoundly understand and significantly enhance the relative DfE performance of a new product compared to the similar competitive products.Finally,we apply an optical mouse development project as a case to elaborate and demonstrate the effectiveness of the proposed methodology.These analytical results can let us understand the DfE performance ranking and acquire the maximum reduced quantity of each DfE criterion for each module of a new product.Meanwhile,to enhance the green competitiveness of the new product,we recommend that the engineers should decrease the area of the circuit board of the new product.In addition,the material of the USB cable for the new product should be switched from the PVC material to the PE material.     

一种新的基于贪婪法的CDM时隙分配最优化算法

引入了协同决策的思想,研究一种新的地面等待策略-基于协同决策的地面等待(GDP-E).首先研究了GDP-E的实施过程以及其中的算法,其次,基于Compression算法的单元受限的现状,分析研究了地面等待程序必须考虑的各空中交通参与方的影响和地位,并建立了数学模型,借助贪婪法求局部最优的思想协同优化了各方的利益,提出了新的"压缩算法",为保证航空公司拥有时隙的公平性,文中采用了补偿函数来强化或弱化对航空公司的公平性.仿真结果显示:此改进算法在很大程度上提高了机场的运作效率,减小了航空公司的总延误成本,保证了航空公司服务对象的利益,且算法具有自适应能力,易于工程实现.