An Efficient Algorithm for Software Generation of Binary Linear Recurrences

We describe a method for efficient software generation of binary linear sequences. Suppose that a machine sized word can hold an unsigned integer between 0 and 2^w–1 and a binary linear sequence (s^(t))_t0 has a characteristic polynomial of degree n having l nonzero coefficients. Then given nw initial bits of the sequence, it is possible to generate successive blocks of (s^(t))_t0 of length w bits each. The time required to generate each block is equal to the time required to perform l bitwise XOR operations on machine sized words. Compared to the basic method of sequence generation, this provides a w-fold increase in speed.Acknowledgement We would like to thank Subhamoy Maitra, Sandeepan Choudhury and Kishan Chand Gupta for discussions and helpful comments. We would also like to thank Professor Harald Niederreiter for pointing out that Lemma 2 can be easily derived from Corollary 1 of [4]. Finally, we thank the reviewers for pointing out several typos in the paper.     

An Algorithm for Zero-One Fractional Programming

A fractional program with bivalent variables can be solved as a direct extension of Balas' zero-one linear algorithm. A surrogate constraint extending that of Geoffrion for the linear case is devised. The method is more general than the one developed recently by Florian and Robillard since it sets no restrictions on the signs of the coefficients of the objective function. Computational experience indicates the superiority of the proposed method.     

多属性决策问题的交互线性分式规划算法

基于决策者的线性效用函数提出了一种求解多属性决策问题的交互线性分式规划算法.     

一种高效的图像去噪算法

针对图像去噪的速度以及可能出现的阶梯效应等问题进行了研究,提出了一种高效的图像去噪算法.该算法在贝叶斯框架下,首先引入调和模型作为原始图像的先验模型,并用伽马分布作为未知参数的先验分布模型;然后,用变分近似的方法推导最大后验概率;基于此推导过程,同步地估计原始图像和未知参数的最优值,实现图像去噪.实验结果证明了该算法的高效性,通过与其它算法的比较,该算法体现了速度快、效果好的优点,且去噪后的图像不会出现阶梯效应等问题.     

Orthogonal Transformations on Solid Substrates: Efficient Avenues to Surface Modification

The performance of solid substrates is not only governed by their molecular constitution, but is also critically influenced by their surface constitution at the solid/gas or solid/liquid interface. In here, we critically review the use of orthogonal chemical transformations (so‐called click chemistry) to achieve efficient surface modifications of materials ranging from gold and silica nanoparticles, polymeric films, and microspheres to fullerenes as well as carbon nanotubes. In addition, the functionalization of surfaces via click chemistry with biomolecules is explored. Although a large host of reactions fulfilling the click‐criteria exist, pericyclic reactions are most frequently employed for efficient surface modifications. The advent of the click chemistry concept has led—as evident from the current literature—to a paradigm shift in current approaches for materials modification: Away from unspecific and nonselective reactions to highly specific true surface engineering.     

An Efficient Algebraic Algorithm for the Geometric Completion to Involution

 We describe an adaption of a differential algebraic completion algorithm for linear systems of partial differential equations that allows us to deduce intrinsic differential geometric information like the number of prolongations and projections needed for the completion. This new hybrid algorithm represents a much more efficient realisation of the classical Cartan–Kuranishi completion than previous purely geometric ones. A classical problem in geometric completion theory is the existence of δ-singular coordinate systems in which the algorithms do not terminate. We develop a new and a very simple criterion for δ-singularity based on a comparison of the Janet and the Pommaret division. This criterion can also be used for the direct construction of δ-regular coordinates. Received: July 28, 2000; revised version: October 16, 2001     

An Efficient Computational Alternative to 'Using Linear Programming to Design Oil Pollution Detection Schedules'

In Olson, Wright, and McKell's recent paper on the design of oil pollution detection schedules, an interesting and inventive development and application of a Markov Decision Process was presented. Optimal schedules for patrol flights of surveillance aircraft were found using linear programming. In this paper the model has been reformulated as a discrete time semi-Markov process. Significant computational advantages accrue from this alternative approach.     

求Hankel型线性方程组的一种算法

本文给出了矩阵为Hankel矩阵的充要条件,由此定义了一种新的矩阵-Hankel型矩阵,说明了Hankel矩阵是Hankel型矩阵的特殊情况.为了降低Hankel型线性方程组的计算量和减小这类算法的误差,利用Hankel型矩阵的位移性质,给出了求Hankel型线性方程组的一种算法.矩阵为Hankel矩阵时,该算法与Gohberg-Kailath-Koltracht算法相比计算量相当,但改进了精度;矩阵为一般Hankel型矩阵时,该算法与Cholesky分解算法相比计算量大为减少,极大改进了精度.     

WPERF+:一种有效的分布式查询处理优化算法

分布式查询是一种网络通信成本较大的查询过程,设计和开发出有效的查询策略和技术是分布式查询面临的挑战。本文展示了一种新的分布式查询的算法。即WPERF 连接算法,它结合了W算法和PERF算法的特点。进一步强化了W算法和PERF的性能。文章从理论上证明了WPERF 算法具有有效降低分布式查询处理成本的效能。     

含变系数的线性分数阶微分方程的解析解(英文)

本文利用算子级数给出了含变系数线性分数阶微分方程的解析解,并通过几个例子说明了解析表达式的重要性.另外,我们还得到了分数阶Gronwall不等式的微分形式和积分形式,它们是经典Gronwall不等式的推广.     

一种有效的圆形窗口线裁剪算法

根据线段两端点相对于圆形窗口的可能位置讨论裁剪结果。当两端点都在圆形窗口之外时,通过圆切线斜率与线段斜率的比较,及点区域判别来判断线段与窗口的相交情况。在确定线段与圆形窗口有交点的情况下,应用参数化形式求交运算,简化求交方程的构造。实验结果表明,新算法显著提高了裁剪效率。     

Crack Configurations Related by Fractional Linear Mapping

In this paper,the method of fractional linear mapping is introduced for the analysis of the plane crack in 3-space under pressure loading. With this method we can collect information on stress intensity factors for crack configuration besides elliptic crack. The numerical example for the elliptic crack under uniform pressure is presented.     

一个求解大型线性方程组的自适应CGNR算法

提出了一个求解大型非对称线性方程组的混合迭代算法,是基于法方程的自适应CGNR算法,该算法利用了多项式预条件和残差多项式估计特征值等技术,保持了CGNR方法原有的稳健性,又加快了迭代收敛速度。     

An Efficient Algorithm to Construct an Orthonormal Basis for the Extended Krylov Subspace

Subspace projection methods based on the Krylov subspace using powers of a matrix $A$ have often been standard for solving large matrix computations in many areas of application. Recently, projection methods based on the extended Krylov subspace using powers of $A$ and $A^{−1}$ have attracted attention, particularly for functions of a matrix times a vector and matrix equations. In this article, we propose an efficient algorithm for constructing an orthonormal basis for the extended Krylov subspace. Numerical experiments indicate that this algorithm has less computational cost and approximately the same accuracy as the traditional algorithm.     

An Efficient Crossing-Line Crowd Counting Algorithm with Two-Stage Detection

Crowd counting is a challenging task in crowded scenes due to heavy occlusions, appearance variations and perspective distortions. Current crowd counting methods typically operate on an image patch level with overlaps, then sum over the patches to get the final count. In this paper we describe a real-time pedestrian counting framework based on a two-stage human detection algorithm. Existing works with overhead cameras is mainly based on visual tracking, and their robustness is rather limited. On the other hand, some works, which focus on improving the performances, are too complicated to be realistic. By adopting a line sampling process, a temporal slice image can be obtained for pedestrian counting without the need for visual tracking. Only ten low level features are extracted from the input image to establish a feature vector. As a result, our algorithm is more efficient and accurate than existing methods. Pedestrians in the temporal slice image are then located by the two-stage detection algorithm, which is largely based on support vector machine and affinity propagation clustering. Moreover, a novel algorithm is proposed to determine the moving directions of pedestrians by comparing the centers of them in two temporal slice images. Extensive experiments reveal that our system achieves satisfaction performances in terms of both robustness and efficiency.     

An Exact Asymptotically Efficient Confidence Bound for Reliability in the Case of the Weibull Distribution

This paper presents a simple method for obtaining exact lower confidence bounds for reliabilities (tail probabilities) for items whose life times follow a Weibull distribution where both the “shape” and “scale” parameters are unknown. These confidence bounds are obtained both for the censored and non-censored cases and are asymptotically efficient. They are exact even for small sample sizes in that they attain the desired confidence level precisely. The case of an additional unknown “location” or “shift” parameter is also discussed in the large sample case. Tables are given of exact and asymptotic lower confidence bounds for the reliability for sample sizes of 10, 15, 20, 30, 50 and 100 for various censoring fractions.     

Fractional Order Linear Active Disturbance Rejection Control for Linear Flexible Joint System

A linear flexible joint system using fractional order linear active disturbance rejection control is studied in this paper. With this control scheme, the performance against disturbances, uncertainties, and attenuation is enhanced. Linear active disturbance rejection control (LADRC) is mainly based on an extended state observer (ESO) technology. A fractional integral (FOI) action is combined with the LADRC technique which proposes a hybrid control scheme like FO-LADRC. Incorporating this FOI action improves the robustness of the standard LADRC. The set-point tracking of the proposed FO-LADRC scheme is designed by Bode's ideal transfer function (BITF) based robust closed-loop concept, an appropriate pole placement method. The effectiveness of the proposed FO-LADRC scheme is illustrated through experimental results on the linear flexible joint system (LFJS). The results show the enhancement of the robustness with disturbance rejection. Furthermore, a comparative analysis is presented with the results obtained using the integer-order LADRC and FO-LADRC scheme.     

基于图像纹理特征的目标快速检索

在讨论共生矩阵的基础上,提出了一个通过图像分割获取目标图像纹理特征,进而实现图像快速检索的方法。试验表明,该方法检索目标图像的可靠性较高,具有良好的应用价值。     

两线性流形之间夹角的算法

本文将3维欧氏空间中直线与平面的夹角推广到n维欧氏空间中两线性流形的夹角,并用带线性和二次等式约束的二次规划刻画这个夹角,从而,把求两线性流形夹角的问题转化为求解非凸二次规划问题,由此,给出了计算这种夹角的一个算法和数值算例.在该数值算例中,我们应用Gr(o)bner基理论求解非凸二次规划问题.