Text Categorization Based on Regularized Linear Classification Methods

A number of linear classification methods such as the linear least squares fit (LLSF), logistic regression, and support vector machines (SVM's) have been applied to text categorization problems. These methods share the similarity by finding hyperplanes that approximately separate a class of document vectors from its complement. However, support vector machines are so far considered special in that they have been demonstrated to achieve the state of the art performance. It is therefore worthwhile to understand whether such good performance is unique to the SVM design, or if it can also be achieved by other linear classification methods. In this paper, we compare a number of known linear classification methods as well as some variants in the framework of regularized linear systems. We will discuss the statistical and numerical properties of these algorithms, with a focus on text categorization. We will also provide some numerical experiments to illustrate these algorithms on a number of datasets.     

线性迭代系统的Hyers-Ulam-Rassias稳定

文章讨论在Banach空间中的一维线性迭代系统的Hyers-Ulam-Rassias稳定,将系统化成向量与矩阵的形式,并通过讨论矩阵的范数来讨论系统Hyers-Ulam-Rassias稳定。     

解构规则对英汉同声传译自我训练的启示

同声传译一直被看作是最难的口译形式,它要求同传译员有极高的心智和操作技能。论文根据同传中最主要的一个难点,即何时"解构",结合同传实例,希望能对英语专业学生及同传爱好者进行自我训练有所启示。首先分析了解构规则的特点,如何化整为零、按意群切分语句等方法。然后,在其理论基础上进一步探讨译员如何主动断句、把握速度,以集中更多注意力于听解,保证同传的"基本同步"。     

网络课程开发的工程化方法研究

为了降低课程开发风险．提高课程质量,解决网络课程开发过程中缺乏系统化方法、进度不可控的问题．北京邮电大学网络课程“高级程序语言（JAVA）”的开发过程引入工程化的开发方法,按项目管理的思想组建开发团队,以专业特长划分课程开发小组,将开发任务拆分成不同阶段,明确各小组在不同开发阶段的职责和任务,并运用迭代式方法,将课程开发看作是一个动态的过程,持续改进课程,提高开发效率和质量。     

运动车辆车牌图像的超分辨率重建

为了改善实际交通环境中运动车辆车牌图像的质量,提出一种新的超分辨率重建方法,即通过融合低分辨率图像间的互补信息得到一幅高分辨率车牌图像.首先,在超分辨率重建正则化框架下引入梯度残差项作为一个梯度强制项来改善重建图像的质量.其次,为了提高重建算法的鲁棒性,用L1范数度量数据残差项和梯度残差项.最后,用最速下降法求解相应的最小能量泛函.模拟和实际视频图像序列的实验结果验证了所提方法的有效性和实用性,所提方法在重建图像的信噪比指标和视觉效果方面均优于双三次插值和DAMRF法.     

硅桥的一种近似解法

利用数值迭代方法,本文提出一种硅桥的近似解法,可用于硅压力传感器的温度补偿时电阻阻值的计算.     

大规模半定规划问题的正则化方法及收敛性

为了改进求解大规模约束条件的半定规划问题的方法.首先通过经典的二次正则法,将一般的半定规划问题(SDP)的标准形式进行形式的转化.然后通过研究转化后问题的最优性条件,给出了求解一般的半定规划问题的正则化算法及其收敛性证明.在实际中,处理大规模约束条件的半定规划问题(SDP)时,该方法表现出很好的性能.     

Wavelet-based deconvolution of ultrasonic signals in nondestructive evaluation

INTRODUCTION Deconvolution of ultrasonic signals is defined as the solution of the inverse problem of convolving an input signal, known as the system function h(n), with a medium reflectivity function x(n) and can be rep- resented by y(n)=h(n)*x(n) η(n), (1) where y(n) is the measured signal, * denotes the convolution operation and η(n) is the additive noise. Recovering x(n) from the observation y(n) leads to improving the appearance and the axial resolution of the RF-signals by removin…     

Banach空间中增生型变分包含解的具随机混合型误差的Ishikawa和Mann迭代逼近

引入和研究了Banach空间中一类增生型变分包含解的存在性及其具随机混合型误差的Ishikawa和Mann迭代程序的收敛性问题。     

Banach空间中非扩张映象的几个收敛定理

在适当的条件下得出了Banach空间中非扩张映象的几个收敛性定理,所得结果改进和推广了文〔5,6,8,9,10,11,12〕的主要结果。