基于模糊判别的指纹识别算法探讨

指纹识别在社会各个领域应用都非常广泛.本文从指纹识别的原理和应用出发,介绍一种基于模糊判别的指纹识别算法.     

Distinguishing attacks on stream ciphers based on arrays of pseudo-random words

In numerous modern stream ciphers, the internal state consists of a large array of pseudo-random words, while the output key-stream is a relatively simple function of the state. It has been heuristically shown in several situations [3], [8], [9], [10], [11] and [14] that this structure may lead to distinguishing attacks on the cipher. In this note we present a more rigorous treatment of this structural attack. First, we present a rigorous proof of the main probabilistic claim behind it in the basic cases. We then apply it concretely to the cipher sn3 [12], and demonstrate that the heuristic assumptions of the attack are remarkably precise in more complicated cases.     

Exploring alternatives for transition verification

When an implementation under test (IUT) is state-based, and its expected abstract behavior is given in terms of a finite state machine (FSM), a checking sequence generated from a specification FSM and applied to an IUT for testing can provide us with high-level confidence in the correct functional behavior of our implementation. One of the issues here is to generate efficient checking sequences in terms of their lengths. As a major characteristics, a checking sequence must contain all β-sequences for transition verification. In this paper, we discuss the possibility of reducing the lengths of checking sequences by making use of the invertible transitions in the specification FSM to increase the choice of β-sequences to be considered for checking sequence generation. We present a sufficient condition for adopting alternative β-sequences and illustrate typical ways of incorporating these alternative β-sequences into existing methods for checking sequence generation to reduce the lengths. Compared to the direct use of three existing methods, our experiments show that most of the time the saving gained by adopting alternative β-sequences falls in the range of 10–40%.     

An improved SVD-based watermarking technique for copyright protection

The drawbacks of SVD-based image watermarking are false positive, robust and transparency. The former can be overcome by embedding the principal components of the watermark into the host image, the latter is dependent on how much the quantity (i.e., scaling factor) of the principal components is embedded. For the existing methods, the scaling factor is a fixed value; actually, it is image-dependent. Different watermarks need the different scaling factors, although they are embedded in the same host image. In this paper, two methods are proposed to improve the reliability and robustness. To improve the reliability, for the first method, the principal components of the watermark are embedded into the host image in discrete cosine transform (DCT); and for the second method, those are embedded into the host image in discrete wavelets transform (DWT). To improve the robustness, the particle swarm optimization (PSO) is used for finding the suitable scaling factors. The experimental results demonstrate that the performance of the proposed methods outperforms than those of the existing methods.     

电力系统同调机群的识别方法

在对电力系统中同调机群的识别方法进行研究的同时，并对以往的各种同调机群的识别方法也进行了归纳总结，针对这些方法所存在的问题，给出了一种新的较为实用的同调机群识别方法。     

拟合空间曲线与平面交点的求解及判断

通过分析比较，采用Ｂｅｓｉｅｒ方法拟合所需的一组空间曲线，并用平面切割曲线，求解出平面与拟合空间曲线的交点．在求交过程中引入优化方法判断交点真伪性，从而得到所需拟合的空间曲线与平面相交交点．     

A neural network to predict attendance of paediatric patients at outpatient clinics

The development of a feed-forward neural network to predict attendance and non-attendance at a hospital outpatient clinic is described. Particular emphasis is given to the post-processing applied to the network output, and to the choice of information presented to the network. The effect of individual inputs on the performance of the network is examined, and two methods of dealing with the problem of ambiguous input data are explored. It is shown that good results (approximately 90% accuracy) are achieved with a feedforward network — having 15 input nodes, a single hidden layer of five nodes and one output node with supervised backpropagation — even where data is limited, and that an understanding of the problem can lead to the modification of standard procedures and improved network performance.     

基于模糊理论的教学软件质量评估模型

通过分析目前国内外使用的几种评估软件质量的方法,结合教学软件具体实际和综合考虑,提出利用模糊理论评估教学软件质量的模型,改善传统评估方法中不合理和复杂性的弊端,并能方便快捷地得出科学、准确、客观的评估结果,在评估电子商务模拟教学软件实际应用中有良好的运行效果.     

模2n加整体逼近模2加产生的噪声函数的概率分布研究

该文证明了模2n加变换以6种不同的方式整体逼近模2加时产生的噪声函数取值概率的数值分布相同,给出了6种噪声函数的概率分布之间的相互转化关系,并给出了6种整体逼近所产生的噪声函数的取值概率的计算公式以及概率值平方和的计算公式,并修正了三元模2加整体逼近模2n加时所产生的噪声函数取值概率的平方和的计算公式。这些结论在区分攻击中有一定的应用价值。     

基于暂态零序无功功率的小电流系统单相接地选线

根据小电流接地系统发生单相接地故障时,在特征频带(SFB)内馈线输入阻抗的相频特性呈容性的特点,利用小波变换提取此频带内的暂态零序电流分量及经Hilbert变换的暂态零序电压分量;采用小波分解后的尺度系数及小波系数求得暂态零序无功功率进行故障选线。经过大量的Matlab仿真测试表明:该选线方法能够准确识别单相接地故障线路,可靠性和灵敏性较高。