结合look-ahead值排序的自适应分支求解算法

基于新近提出的自适应分支约束求解框架,结合look-ahead值启发式,提出一种新的约束求解算法AdaptBranchLVO。为验证算法效率,在标准测试库上进行了充分对比实验。结果表明,新提出算法在效率上明显优于已有的自适应分支求解算法。     

High-performance CORDIC rotation algorithm based on look-ahead techniques

The Coordinate Rotation Digital Computer (CORDIC) algorithm is a well-known iterative method for the computation of vector rotation. However, the major disadvantage is its relatively slow computational speed. In this article, a high-performance CORDIC rotation algorithm is proposed. Using the look-ahead techniques, the rotation directions can be predicted directly from the input angle. The proposed method can increase performance under maintaining the precision. The experimental results show the efficiency of the proposed methods.     

A look-ahead Levinson algorithm for general Toeplitz systems

The authors present an extension of Levinson's algorithm that is guaranteed to be weakly stable for a large class of general Toeplitz matrices, namely, those that do not have many consecutive ill-conditioned leading principal submatrices. The new algorithm adapts itself to the given Toeplitz matrix by skipping over all the ill-conditioned leading principal submatrices encountered during the solution process. This is done by a look-ahead strategy that monitors the condition of the leading principal submatrices and, if necessary, switches to a block step of suitable size. The overhead of the look-ahead algorithm is typically small compared to the classical Levinson algorithm, and in addition a reliable condition number estimate is produced     

基于CORDIC算法的流水型DDS设计与研究

在分析CORDIC算法原理基础上,提出了一种基于CORDIC算法的流水型DDS结构,用以取代传统的ROM查找表法。同时对输入角度进行预处理,对迭代结果进行后处理,实现了整个周期的三角函数计算。设计采用verilog语言描述,在QuartusⅡ9．0下编译综合,以及Modelsim-altera6．4进行了仿真。结果表明,该算法比传统算法具有计算角度范围大、高速度和低资源的优势。     

结合自适应核函数的Mean-shift改进算法

为解决Mean-shift算法采用固定跟踪窗口造成的目标定位精度低的问题,结合视觉显著性检测和像素灰度相似度,提出一种采用自适应核函数的Mean-shift跟踪算法。该方法以灰度相似度加权的视觉显著性特征确定目标区域,并结合Epanechnikov核函数构建自适应核函数,使跟踪窗口自适应目标大小变化,降低目标尺度变化的影响,实现目标的有效跟踪。实验结果证明,该方法能够有效跟踪尺度变化目标,处理每帧图像耗时小于25ms,满足实时性需求。     

一种高精度改进型SHR基音检测算法

利用正弦语音模型中浊音存在的谐波与子谐波,在SHR(subharninctoharmonicratio)算法的基础上,提出了一种改进型高精度基音检测算法ISHR(improvingsubharninctoharmonicratio)。根据幅度调制和频率调制在语音分析中的特性、频域中幅度值和自相关频率比值,该方法采用基于正弦模型的均方误差对语音进行检测,提取出准确基音。仿真结果表明此种算法在基音提取中具有高精度及高可靠性。     

Improved layered MIMO detection algorithm with near-optimal performance

A new layered symbol detection algorithm for multiple-input multiple-output systems is presented. In this scheme, the layers are divided into two groups and detected differently. For the layer with the smallest post-detection signal-to-noise ratio, an exhaustive search is performed over the signal constellation; for the remaining layers the conventional iterative vertical Bell laboratories layered space-time (V-BLAST) technique is utilised. The proposed algorithm also uses a different symbol detection ordering from that recommended in the original V-BLAST algorithm. Simulation results show that the error rate performance of the proposed detection algorithm approaches closely that of an optimal maximum likelihood detector with no reduction in the symbol detection throughput, while the computational complexity is less than |Q| times that of V-BLAST, where |Q| is the cardinality of signal constellation Q.     

改进的基于拉普拉斯先验的贝叶斯压缩感知算法

贝叶斯压缩感知(Bayesian Compressed Sensing,BCS)通过稀疏贝叶斯回归模型中相关向量机(Relevance Vector Machine,RVM)的学习来解决压缩感知(Compressed Sensing,CS)中的信号重构问题。本文通过修正基于拉普拉斯先验BCS的噪声模型,较好地实现了含噪CS信号的重构。它主要利用稳健型相关向量机(Robust RVM,RRVM),改进了基于拉普拉斯先验的BCS算法。它通过对每个观测噪声方差系数进行最优化估计,来消除内外部噪声对信号重构的影响。相关的仿真验证了在外部脉冲噪声以及内部高斯白噪声共同干扰条件下,相比原始BCS算法,改进算法具有更好的重构性能和稳定性。     

Improved locally distorted CPFDTD algorithm with provable stability

The contour path finite difference time domain (CPFDTD) method has been shown to give accurate results for curved metal structures. However, the numerical stability of this scheme is not guaranteed and significant skill is required to generate an appropriate grid. The authors present a modification to the two-dimensional CPFDTD method which ensures stability and which permits simple generation of the locally distorted grid. The accuracy of the scheme is demonstrated through calculation of the resonant frequencies of circular cylindrical resonators     

Improved RFID anti-collision algorithm

In this paper, we propose an improved anti-collision technique based on the binary search algorithm. The improvement is achieved thanks to the manner of the requests’ building. This latter reduces considerably the responding tag's numbers and therefore, decreases the probability of bit's collision. Further, the algorithm provides a noticeable advantage for the length of transmitted binary data compared against basic binary search and dynamic binary search algorithms. Besides, it provides same performance in terms of average request's number making the identification process faster, and the expose time of information is then reduced.     

一种改进的完全搜索块匹配算法

完全搜索块匹配算法是图像序列稳定中常用的运动估计方法,在传统的完全搜索块匹配算法中,在搜索区域中图像序列的当前帧和参考帧对应的像素对对匹配结果的贡献是完全一样的,这样使得算法的性能容易受到待稳定的图像序列中各种噪声的影响。针对这个不足,提出了一种改进的完全搜索块匹配算法。在新的匹配准则中,搜索区域中图像序列的当前帧和参考帧对应的像素对对匹配结果是否有贡献取决于它们灰度值之差的绝对值与预先设定的门限值进行大小比较的结果,对应的灰度值之差的绝对值不超过该门限值的像素对对匹配结果有贡献,而且贡献大小受到与像素对位置相关的加权处理,否则该像素对对匹配结果无贡献。实验结果证明了该算法的优越性。     

An adaptive-weighted two-dimensional data aggregation algorithm for clustered wireless sensor networks

In this paper, an Adaptive-Weighted Time-Dimensional and Space-Dimensional （AWTDSD） data aggregation algorithm for a clustered sensor network is proposed for prolonging the lifetime of the network as well as improving the accuracy of the data gathered in the network. AWTDSD contains three phases： （1） the time-dimensional aggregation phase for eliminating the data redundancy; （2） the adaptive-weighted aggregation phase for further aggregating the data as well as improving the accuracy of the aggregated data; and （3） the space-dimensional aggregation phase for reducing the size and the amount of the data transmission to the base station. AWTDSD utilizes the correlations between the sensed data for reducing the data transmission and increasing the data accuracy as well. Experimental result shows that AWTDSD can not only save almost a half of the total energy consumption but also greatly increase the accuracy of the data monitored by the sensors in the clustered network.     

改进的Hopping Code算法

传统的汽车电子钥匙等遥控或命令辨别场合的跳码系统采用的是对称密码体制,而在本文中引入了公钥算法的思想,能在32比特的情形下为电子锁提供足够的安全性能,由此为其在市场上的推广提供了相当的优势。     

改进的快速SPIHT算法

SPIHT算法是一种简单、有效的嵌入式零树编码算法,但是,它需要大量存储空间,而且存在多次重复运算,因而复杂程度高,时间消耗大,不利于实时压缩。改进的SPIHT算法针对原算法的不足引入了“最小阈值”和“最小输出位”,同时改变了原算法的扫描顺序,降低了算法的复杂程度,并使其更有利于并行优化处理。实验证明,改进后的算法减少了编解码过程中的存储容量和时间消耗,而重建图像的峰值信噪比和人眼视觉效果与原算法相当。     

一种改进的模糊增强算法

针对在图像处理的过程中要面对许多含糊不清的情况,采用模糊集理论这一有效的数学工具是非常必要的。本文在研究模糊增强传统算法的基础上,提出了一种新的隶属度函数。它克服了传统算法中的变换强度较小、运算速度较慢和丢失部分灰度信息等缺点。另外,为了更好地保持图像的细节,本文在模糊增强算法中引入了平滑处理,完善了图像的模糊增强系统...     

改进的bregman加速算法

在使用CT进行图像重建的过程中,需要在不同角度下对目标对象进行采样,然后利用图像重建算法生成重建结果,由于采样的数据越多,重建速率越慢,往往需要在不完全的采样角度下对图像进行重建,即稀疏重建.为了对传统稀疏重建算法的迭代速度进行改进,在传统bregman图像重建算法的基础上提出了一种新的加速迭代算法.该算法以bre-g...     

一种改进的MCMC移动步骤的U粒子滤波算法

粒子退化是标准粒子滤波算法的主要缺陷。针对这一缺陷,提出了一种改进算法,在提出的具有MCMC移动步骤的U粒子滤波算法上进行性能分析,从样本产生和对MCMC移动步骤的使用两个方面对算法进行改进,减小了算法的计算量,提高算法的运算速度。仿真结果表明,改进后的算法大大减少了运算量,从一定程度上提高了运行效率。     

基于CMRA路由协议改进算法

为了延长无线传感网络的生存时间,需要设计满足高效率、低功耗的路由算法。一种CMRA（intercluster head multi-hop routing algorithm）算法被提出来,这种算法通过节点通信能量消耗模型建立最小能量路径树,但CMRA对于簇头选择的能量分配不均衡,造成簇头结点负载过重。提出一种新的路由算法CMRA-EE（CMRA-energy efficient）,在簇头选举阶段引入节点能量参数,同时将簇头节点能量与距离作为代价参数,从而平衡了网络节点能耗。通过仿真对CMRA-EE算法进行性能分析与评价,结果显示,CMRA-EE算法在延长无线传感网有效生存时间方面比CMRA算法有了明显的改善。     

基于感知熵的MPEG—2AAC量化模块的改进

在MPEG－1和MPEG－2系列的音频编码中,其量化模块都采用Brandenburg提出的双循环结构,它作为标准的参考算法在对编码质量的评估等工作中能起到不错的效果,但用于实时音频编码时,由于它的收敛速度较慢,往往无法满足要求,本文对MPEG－2 AAC的量化模块进行了分析,引入了基于感知熵的比特估算技术,并针对其缺陷重新设计了该模型,实验结果表明新算法在迭代次数等方面有明显改进。     

A technique for the design of systolic arrays with bit-level pipelining

This paper describes a method for designing systolic structures with bit-level pipelining. The proposed technique starts with the signal flow graph representation of a given algorithm. A new signal flow graph rule, called the gain transfer rule is introduced to achieve bit-level pipelining. Using this approach, systolic arrays with bit-level pipelining are derived for a general recursive digital filter and a convolver. The proposed technique is quite general and has also been applied to obtain systolic structures for other problems such as vector transformation. In comparison with some previously reported designs, the new architectures are characterized by simpler basic processing cells and faster data throughput rate or smaller chip area requirements.The work of the first two authors was supported by an NRC Resident Research Associateship.