基于朴素贝叶斯模型的邮件过滤技术

针对朴素贝叶斯算法应用于反垃圾邮件过滤时,其有效性十分依赖于对邮件内容的有效建模,而邮件内容建模方面研究尚不成熟限制了贝叶斯方法在垃圾邮件过滤中的性能.采用了三种概率分布对邮件内容进行建模,据此提出了3种概率分布下的朴素贝叶斯算法.为了提高训练效率,算法采用了一种增量式的垃圾邮件过滤方法.在trec05p-1、trec06p两个公开数据集上对这3种贝叶斯算法进行了实验对比,分析出三种贝叶斯分布的适用范围.从不同分布的邮件内容建模角度出发,为过滤垃圾邮件的方法选择提供了有效依据.     

A Historical Overview of Internet Reference Services for Distance Learners

SUMMARY

The advent of library services and collections on the Internet revolutionized reference services to students enrolled in distance learning programs. Prior to the Internet, reference librarians who supported distance learning programs had few methods, and many of them costly, to provide the equivalent library services advocated by the ACRL Guidelines. Through the Internet, these librarians were able to approximate the services and resources that had always been available to students who came into the library. This article describes the development of reference services on the Internet in a variety of libraries that support distance learners.     

基于双机协作方式的电子邮件监控系统的研究与设计

针对电子邮件内容的安全问题,提出了电子邮件监控系统的体系结构,把整个系统分为邮件捕获层、邮件还原层、用户层三个部分来设计并用Java语言实现;重点研究了双机协作方式的邮件数据获取方法及邮件内容的解码与还原方法.实验结果表明该系统能够对电子邮件内容进行有效的监控.     

The Design, Implementation, and Operation of a Hungarian E-Mail Reader

The market's leading Hungarian Global System for Mobile Communications (GSM) operator—Westel—has recently introduced a Hungarian e-mail reading system as a regular service. It was implemented on the basis of an experimental system developed at the Department of Telecommunications and Telematics of the Budapest University of Technology and Economics (DTT BUTE). In this article, the considerations involved in the design and implementation decisions of both the experimental and the industrial systems will be described. Results of the first 10 weeks of regular use of the industrial system will also be given.     

椭圆曲线密码技术在安全电子邮件中的应用

为了解决电子邮件在网络传输中的安全问题,防止邮件机密信息被他人截取,文章在充分研究了椭圆曲线加密技术和安全电子邮件的前提下,设计并实现了基于椭圆曲线加密技术的安全电子邮件系统。实验证明该系统相对于一般的电子邮件系统,安全性大大提高,有效地解决了邮件传输过程中的泄密问题。     

基于贝叶斯的垃圾邮件过滤算法的研究

基于内容的垃圾邮件过滤问题是Internet安全技术研究的一个重点问题,而基于贝叶斯的分类方法在垃圾邮件处理上表现出了很高的准确度,因此受到了广泛的关注。在朴素贝叶斯算法的基础上,提出了一种基于最小风险贝叶斯方法同Boosting算法相结合的邮件过滤改进算法,提高了分类的精确度。实验证明,算法在邮件过滤中有更好的表现。     

一种基于矢量空间模型的垃圾邮件去重复技术

随着互联网的发展，电子邮件成为了一类重要应用。然而垃圾邮件的产生极大的制约了电子邮件的应用。文中提出了一类基于矢量空间模型的垃圾邮件去重复技术（VMF），从删除重复邮件的角度，给出了一种垃圾邮件过滤的方法。与现存技术相比，VMF在召回率和适应性等方面均有显著提高。     

Asynchronous and distributed process improvement: the role of collaborative technologies

Abstract. The recent proliferation of low-cost computer networks has driven the development of a new type of organization, in which geographical and time constraints to collaboration among process teams have been gradually removed. As these organizations have to cope with a fast pace of change, they rely increasingly on distributed and asynchronous process improvement (PI) groups to redesign their processes. Yet little is known about the effects of asynchronous group support systems (GSSs) on PI groups. We investigate the effects of asynchronous GSSs on PI groups through a two-stage action research study of 38 such groups in three organizations, one in Brazil and two in New Zealand, over 4 years and 4 months. Different PI groups voluntarily conducted all, part or none of their communication through an e-mail conferencing (EC) tool. The research suggests that EC support causes a decrease in the organizational costs associated with PI groups, which, combined with an increase in the number of possible simultaneous PI groups, generates an increase in overall organizational PI efficiency. The research also suggests a neutral overall effect of EC support on PI group outcome quality. Two explanatory causal models summarizing these effects are developed, and implications for research and industry practice are discussed.     

The finer points of lying online: E-mail versus pen and paper.

The authors present 3 experimental studies that build on moral disengagement theory by exploring lying in online environments. Findings indicate that, when e-mail is compared with pen and paper communication media (both of which are equal in terms of media richness, as both are text only), people are more willing to lie when communicating via e-mail than via pen and paper and feel more justified in doing so. The findings were consistent whether the task assured participants that their lie either would or would not be discovered by their counterparts. Implications for theory and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative analysis of a certified e-mail protocol in mobile environments: A probabilistic model checking approach

Formal analysis techniques, such as probabilistic model checking, offer an effective mechanism for model-based performance and verification studies of communication systems’ behavior that can be abstractly described by a set of rules i.e., a protocol. This article presents an integrated approach for the quantitative analysis of the Certified E-mail Message Delivery (CEMD) protocol that provides security properties to electronic mail services. The proposed scheme employs a probabilistic model checking analysis and provides for the first time insights on the impact of CEMD’s error tolerance on computational and transmission cost. It exploits an efficient combination of quantitative analysis and specific computational and communication parameters, i.e., the widely used Texas Instruments TMS320C55x Family operating in an High Speed Downlink Packet Access (HSDPA) mobile environment, where multiple CEMD participants execute parallel sessions with high bit error rates (BERs). Furthermore, it offers a tool-assistant approach for the protocol designers and analysts towards the verification of their products under varying parameters. Finally, this analysis can be also utilized towards reliably addressing cost-related issues of certain communication protocols and deciding on their cost-dependent viability, taking into account limitations that are introduced by hardware specifications of mobile devices and noisy mobile environments.