计算机学科公选课教学策略的探讨

该文从计算机学科教学手段,教学方法,教学内容,教学观念和教育功能的关系谈论了一些看法。提出了在计算机学科公选课的教学中,突出对学生创新实践能力的培养。     

C语言中“/”影响运算精度问题的探讨

使用C语言编程进行计算的时候常常会因为不注意类型转换产生问题,尤其是在使用除法运算符"/"的时候,经常因为没有注意运算数据类型转换,从而导致运算结果不正确或着说是精度不够的问题。以下就C语言中"/"影响运算精度的问题做简单的探讨,希望助于初学者甚至是有一定编程水平的人更好地使用C语言。     

Web日志挖掘与上网行为习惯分析

本文以某校校园网Web日志挖掘为例,首先阐述如何进行Web挖掘,其次运用该理论分析该校Web日志得到用户上网行为习惯,并给出合理化建议,最后引出进一步探索的方向,为以后工作奠定基础。本文采用的挖掘方法具有通用性和实用性,对于类似时序序列趋势分析都可参考本文。     

A new criterion of delay-dependent asymptotic stability for Hopfield neural networks with time delay.

In this brief, the problem of global asymptotic stability for delayed Hopfield neural networks (HNNs) is investigated. A new criterion of asymptotic stability is derived by introducing a new kind of Lyapunov-Krasovskii functional and is formulated in terms of a linear matrix inequality (LMI), which can be readily solved via standard software. This new criterion based on a delay fractioning approach proves to be much less conservative and the conservatism could be notably reduced by thinning the delay fractioning. An example is provided to show the effectiveness and the advantage of the proposed result.     

Equilibria and their bifurcations in a recurrent neural network involving iterates of a transcendental function.

Some practical models contain so complicated mathematical expressions that it is hard to determine the number and distribution of all equilibria, not mentioning the qualitative properties and bifurcations of those equilibria. The three-node recurrent neural network system with two free weight parameters, originally introduced by Ruiz, Owens, and Townley in 1997, is such a system, for which the equation of equilibria involves transcendental function tanh(x) and its iterates. Not computing coordinates of its equilibria, in this paper, we display an effective technique to determine the number and distribution of its equilibria. Without full information about equilibria, our method enables to further study qualitative properties of those equilibria and discuss their saddle node, pitchfork, and Hopf bifurcations by approximating center manifolds.     

The CAS-PEAL Large-Scale Chinese Face Database and Baseline Evaluations

In this paper, we describe the acquisition and contents of a large-scale Chinese face database: the CAS-PEAL face database. The goals of creating the CAS-PEAL face database include the following: 1) providing the worldwide researchers of face recognition with different sources of variations, particularly pose, expression, accessories, and lighting (PEAL), and exhaustive ground-truth information in one uniform database; 2) advancing the state-of-the-art face recognition technologies aiming at practical applications by using off-the-shelf imaging equipment and by designing normal face variations in the database; and 3) providing a large-scale face database of Mongolian. Currently, the CAS-PEAL face database contains 99 594 images of 1040 individuals (595 males and 445 females). A total of nine cameras are mounted horizontally on an arc arm to simultaneously capture images across different poses. Each subject is asked to look straight ahead, up, and down to obtain 27 images in three shots. Five facial expressions, six accessories, and 15 lighting changes are also included in the database. A selected subset of the database (CAS-PEAL-R1, containing 30 863 images of the 1040 subjects) is available to other researchers now. We discuss the evaluation protocol based on the CAS-PEAL-R1 database and present the performance of four algorithms as a baseline to do the following: 1) elementarily assess the difficulty of the database for face recognition algorithms; 2) preference evaluation results for researchers using the database; and 3) identify the strengths and weaknesses of the commonly used algorithms.     

基于P-FUZZY-PID的飞行器大角度机动控制物理仿真

针对空间飞行器大角度姿态机动控制具有非线性,并要求控制器具有较高的指向精度、姿态稳定度及鲁棒性等特点,应用P-FUZZY-PID复合控制算法,建立了±180°内的模糊规则库,设计了飞行器姿态控制器;系统采用DSP作为星载控制器,光纤陀螺作为姿态敏感器,反作用飞轮作为执行机构,系统程序采用C语言编程,利用单轴气浮仿真实验台实现了物理仿真实验;实验结果证明该控制方法不仅能实现飞行器大角度机动控制,机动响应快,还表现出较好的鲁棒性。     

债务融资、公司绩效与国有银行改革

本文选择中国上市公司2001～2006年的面板数据,利用回归方法研究了中国上市公司债务融资与公司经营绩效之间的关系。研究发现,第一,中国上市公司债务融资与公司经营绩效之间呈负相关关系,这一结果与国外公司金融文献中的预测相反,中国国有银行普遍存在的预算软约束是导致这一现象的根源;第二,债务融资与公司绩效的负相关性随时间的推移在逐渐减弱,这一效应可以归结于近年来中国银行业改革增强了国有银行的独立性,加强了贷款约束。该研究的一个重要启示是,预算硬约束是债务融资发挥治理效应的一个重要前提条件,中国银行业的改革有利于硬化预算约束。     

PCA—BP算法模块化设计的编程实现

BP算法存在收敛性慢、逼近精度差等缺点.因此,在实际应用中往往需要对BP算法进行相应的改进.利用主元分析法(PCA)对数据样本预先进行降维处理,消除数据问的强耦合性,减少模型的复杂性,然后再作为BP的输入样本从而提高模型的解算速度.在此分析的基础上利用Visual Basic采用模块化的设计方法实现对PCA-BP算法的编程,使学习速率能够进行相应自调整和优化,以此来提高BP网络的泛化推广能力,并能够满足设定的误差精度从而达到现场实际运用需要的目的.     

Entanglement of formation and concurrence for mixed states

We review some results on analytical computations of the measures for quantum entanglement: entanglement of formation and concurrence. We introduce some estimations of the lower bounds for the entanglement of formation in bipartite mixed states, and of lower bounds for the concurrence in bipartite and tripartite systems. The results on lower bounds for the concurrence are also generalized to arbitrary multipartite systems.