基于智能卡的远程口令认证方案的研究

基于RSA密码系统和安全单向的哈希函数,提出了一种相对安全的远程口令认证方案。采用个人身份识别码（PIN）与智能卡相结合的双因素认证方式,用户不但可以自主选取用户口令,而且还可以根据自身的需要随时更新口令,极大地增强了系统的安全性,提高了系统的认证效率。     

Matlab中实现阶乘算法的几种途径

本文简要介绍了Matlab,阐述了阶乘的概念,并给出了阶乘算法在Matlab中的几种实现方案。     

运用EXCEL函数进行拉丁方设计

拉丁方设计是科学试验和加工工艺研究中经常用到的试验设计方法,本文通过对拉丁方设计中的配对设计进行实质的分析,提出了运用EXCEL进行拉丁方设计的方法。结果认为,灵活利用Excel的随机函数如RAND、RANDOMBETWEEN等和排序按钮可以快速地进行拉丁方设计。     

求解函数优化问题的遗传算法

从遗传算法的编码、遗传算子等方面剖析了遗传算法求解无约束函数优化问题的一般步骤,并以一个实例说明遗传算法能有效地解决函数优化问题。     

共轴圆线圈和圆板的互感系数计算

本文给出了同轴圆线圈和圆板间互感系数的近似函数表达式。并用Matlab绘制了该互感系数随线板间距离和圆板大小的变化曲线。此外,根据磁感应强度的解析表达式,计算了载流线圈的磁力线分布图,分析了其磁感应强度的分布,并给出了它的径向分布曲线。     

Independent Component Analysis for Time-dependent Processes Using AR Source Model

Independent component analysis is a fundamental and important task in unsupervised learning, that was studied mainly in the domain of Hebbian learning. In this paper, the temporal dependencies are explained by assuming that each source is an autoregressive (AR) process and innovations are independently and identically distributed (i.i.d). First, the likelihood of the model is derived, which takes into account both spatial and temporal information of the sources. Next, batch and on-line blind source separation algorithms are developed by maximizing likelihood function, and their local stability analysis are introduced simultaneously. Finally, computer simulations show that the algorithms achieve better separation of the mixed signals and mixed nature images which are difficult to be separated by the basic independent component analysis algorithms.     

Efficient algorithms for segmentation of item-set time series

We propose a special type of time series, which we call an item-set time series, to facilitate the temporal analysis of software version histories, email logs, stock market data, etc. In an item-set time series, each observed data value is a set of discrete items. We formalize the concept of an item-set time series and present efficient algorithms for segmenting a given item-set time series. Segmentation of a time series partitions the time series into a sequence of segments where each segment is constructed by combining consecutive time points of the time series. Each segment is associated with an item set that is computed from the item sets of the time points in that segment, using a function which we call a measure function. We then define a concept called the segment difference, which measures the difference between the item set of a segment and the item sets of the time points in that segment. The segment difference values are required to construct an optimal segmentation of the time series. We describe novel and efficient algorithms to compute segment difference values for each of the measure functions described in the paper. We outline a dynamic programming based scheme to construct an optimal segmentation of the given item-set time series. We use the item-set time series segmentation techniques to analyze the temporal content of three different data sets–Enron email, stock market data, and a synthetic data set. The experimental results show that an optimal segmentation of item-set time series data captures much more temporal content than a segmentation constructed based on the number of time points in each segment, without examining the item set data at the time points, and can be used to analyze different types of temporal data.     

Adaptive robust fuzzy control for path tracking of a wheeled mobile robot

This paper proposes an adaptive robust fuzzy control scheme for path tracking of a wheeled mobile robot with uncertainties. The robot dynamics including the actuator dynamics is considered in this work. The presented controller is composed of a fuzzy basis function network (FBFN) to approximate an unknown nonlinear function of the robot complete dynamics, an adaptive robust input to overcome the uncertainties, and a stabilizing control input. The stability and the convergence of the tracking errors are guaranteed using the Lyapunov stability theory. When the controller is designed, the different parameters for two actuator models in the dynamic equation are taken into account. The proposed control scheme does not require the accurate parameter values for the actuator parameters as well as the robot parameters. The validity and robustness of the proposed control scheme are demonstrated through computer simulations. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

An algorithm of file encryption based on sum function sequences

An algorithm of file encryption based on sum function sequences is discussed in this paper. A file is encrypted by applying sum function sequences, bits with exclusive-or operation, and circular cryptographic key. Comparing with traditional algorithms and others, it is harder to decode, and the system cost is lower. New encryption algorithms can be made by transforming source codes with sum function sequences, and it can be used to encrypt different files.     

Robust H∞ controller design for continuous‐time piecewise time‐delay systems

This paper investigates the robust H_∞ control problem for continuous‐time piecewise time‐delay systems by using piecewise continuous Lyapunov function. The uncertainties of the systems under consideration are expressed in a linear fractional form. A strict linear matrix inequality approach is developed to obtain delay‐dependent asymptotic stability conditions and H_∞ performance. The H_∞ controller design problem is solved by exploiting the cone complementarity linearization (CCL) method. Finally an example is given to illustrate the application of the proposed approach. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society