网络中的数据加密技术

数据加密技术是实现网络安全的关键技术之一。该文系统地讨论了两种加密技术：对称式加密、公开密钥加密，并探讨了网络中的三种加密方式：链路加密、节点加密和端到端加密。     

Windows加密文件系统加密原理与解密方法研究

微软操作系统给用户提供了加密文件系统EFS用来加密数据。分析了EFS的加密原理,详细介绍了多种情形下的加密文件解密方法。     

一种新的流加密算法——三维CA流加密法

流加密在加密技术中,因其具备加密速度快、加密原理简单容易实现等优点而被广泛应用。本文对流加密法进行了深入研究和分析,在原有的加密法的基础上,撮出了新的加密算法:三维CA加密算法,并对三维CA加密算法进行描述及分析。     

一种新的流加密算法——三维CA流加密法

流加密在加密技术中,因其具备加密速度快、加密原理简单容易实现等优点而被广泛应用.本文对流加密法进行了深入研究和分析,在原有的加密法的基础上,撮出了新的加密算法:三维CA加密算法,并对三维CA加密算法进行描述及分析.     

基于多重分段生成密钥的整盘加密方案

整盘加密可获取比文件级加密更优化更抗攻击能力。然而,单个密钥加密加重了加密对磁盘主密钥的依赖性。为解决这类问题,我们提出一个基于多重分段生成密钥的整盘加密方案。最后分析了该方案的性能、安全性及效率。     

网络安全中基于DES和RSA混合加密技术的研究

在引入网络安全问题的基础上,研究了目前的两种加密体制(对称加密和公钥加密),分别对其思想、方法和特点进行了讨论,着重分析了DES算法和RSA算法。阐述了结合DES算法和RSA算法的混合加密思想,对混合加密技术在结构上进行了详细的描述,同时分析了混合加密的优点。     

浅谈数据库加密的实现及目标

在分析数据在本地数据库存储现状的基础上,提出了要对数据库本身进行加密操作,以解决数据安全问题。总结了数据库加密实现要解决的层次定位、加密项和加密粒度的确定、加密算法的选择和密钥动态管理等问题,给出了一些解决方案,并提出了数据库加密应达到的基本目标。     

关于电子商务安全解决方案的探讨

本文通过对私有密钥加密法和公开密钥加密法的算法原理进行分析,阐述了两种加密法在网络支付中的具体应用过程,并对两种加密法的优缺点进行了比较。     

MD5加密算法浅析及应用

MD5加密算法是一种比较常用的单向加密算法，很多系统的安全保密工作都采用了这种算法。文章先比较了两类加密方式：单向加密和双向加密，单向加密只能对数据加密，不能将密文解密，而双向加密既能对数据加密，还可将密文解密，接着给出MD5算法的特性，叙述了MD5算法，最后结合实际给出一个应用。     

基于DirectShow设计视频加密Filter组件

介绍了视频加密的算法和方案,分析了DirectShow的体系结构,并介绍了利用DirectShow技术开发视频加密Filter组件的主要步骤.利用此技术开发出的视频加密组件可集成到各类基于DirectShow Filter技术开发的应用程序中,实现对视频的加密.     

Uncovering the effect of text structure in learning from a science text: An eye-tracking study

This study examined whether reading a refutational or non-refutational text would induce different cognitive processing, as revealed by eye-movement analyses. Unlike a standard expository text, a refutational text acknowledges a reader’s alternative conceptions about a topic, refutes them, and then introduces scientific conceptions as viable alternatives. Forty university students read one or the other type of text about the phenomenon of the tides. All had alternative conceptions about the topic. Findings showed that at post-test (off-line measure) refutational text readers learned more than non-refutational text readers. Outcomes regarding indices of visual behavior (on-line measures) during reading revealed that refutational text readers fixated the text segments presenting scientific concepts for a longer time overall than non-refutational text readers, in particular during the second-pass reading. Refutational text readers also fixated the refutational segments for a shorter time than non-refutational text readers for the control segments. Furthermore, all indices of visual attention predicted learning only for the refutational text readers. The more the students’ reading of the refutational text was strategic, the better they learned from it. Implications about eye-tracking methodology and the refutational effect are drawn.     

Use of predictive text in text messaging over the course of a year and its relationship with spelling,orthographic processing and grammar

An investigation into the impact of predictive text use upon the literacy skills of primary school, secondary school and university cohorts was conducted over the course of a year. No differences in use of text abbreviations (‘textisms’) were found between predictive text users and nonusers. However, secondary school children who used predictive text made more genuine spelling errors than nonusers. Predictive text was related to use of some specific grammatical violations in school‐age children's text messages but was not related overall to the tendency to make grammatical errors when texting. University students, however, made significantly fewer grammatical errors in their text messages when they used predictive text. Over the course of a year, predictive text use was variable for all age groups. Consistency of predictive text use was unrelated to grammatical understanding, spelling or orthographic processing for primary and secondary school cohorts. Predictive text use was negatively related to morphological awareness for adult participants.     

论新闻文本精神活动流程中的事料

事料是用于文本建构的客观事物和事理。新闻文本的事料存在于社会生活之中,存在于文本建构主体的文本构思之中,存在于新闻文本之中,存在于文本受众的接受之中。     

The role text structure inference skill plays for eighth graders’ expository text comprehension

The present study investigated whether text structure inference skill (i.e., the ability to infer overall text structure) has unique predictive value for expository text comprehension on top of the variance accounted for by sentence reading fluency, linguistic knowledge and metacognitive knowledge. Furthermore, it was examined whether the unique predictive value of text structure inference skill differs between monolingual and bilingual Dutch students or students who vary in reading proficiency, reading fluency or linguistic knowledge levels. One hundred fifty-one eighth graders took tests that tapped into their expository text comprehension, sentence reading fluency, linguistic knowledge, metacognitive knowledge, and text structure inference skill. Multilevel regression analyses revealed that text structure inference skill has no unique predictive value for eighth graders’ expository text comprehension controlling for reading fluency, linguistic knowledge and metacognitive knowledge. However, text structure inference skill has unique predictive value for expository text comprehension in models that do not include both knowledge of connectives and metacognitive knowledge as control variables, stressing the importance of these two cognitions for text structure inference skill. Moreover, the predictive value of text structure inference skill does not depend on readers’ language backgrounds or on their reading proficiency, reading fluency or vocabulary knowledge levels. We conclude our paper with the limitations of our study as well as the research and practical implications.     

Key skills for science learning: the importance of text cohesion and reading ability

To explore the importance of text cohesion, we conducted two experiments. We measured online (reading times) and offline (comprehension accuracy) processes for texts that were high and low cohesion. In study one (n?=?60), we manipulated referential cohesion using noun repetition (high cohesion) and synonymy (low cohesion). Students showed enhanced comprehension accuracy and faster comprehension responses for text that were high in referential cohesion. In study two (n?=?52), we examined connective text designs (‘because’, ‘and’ and ‘no connective’). Students demonstrated enhanced reading times for text using a ‘because’ connective. Additionally, we examined the individual differences (reading ability, science self-concept and self-esteem) as predictors of achievement with science comprehension tasks. Across both experiments reading ability predicted comprehension with both high (noun-repetition text and ‘and’ text) and low cohesion text (synonym text and ‘no connective’ text). These findings highlight the importance of good reading abilities and text cohesion for promoting science comprehension and learning.     

Material-appropriate processing: A contextualist approach to reading and studying strategies

Processing strategies or text adjuncts that are mnemonically effective with some types of text produce no benefits with other text types. A framework for understanding these seemingly inconsistent mnemonic effects across different types of text is presented. The framework suggests that two types of conceptual elaboration are important for free recall: individual-item processing and relational processing. The mnemonic effectiveness of text adjuncts or other manipulations to increase elaboration of a text will depend on: (1) the type of conceptual elaboration induced by the particular text adjunct or study strategy; (2) the type of elaboration invited by the text itself; and (3) the overlap between the processing induced by the text adjunct or study strategy and the processing invited by the text itself. Significant enhancement in recall is anticipated only to the extent that the text adjunct or study strategy encourages processing that is complementary to the processing invited by the material itself. The viability of this framework is demonstrated in a review of the pertinent literature on the mnemonic effects of encoding difficulty. Then, research stimulated by the framework that uses educationally relevant study and text adjuncts (embedded questions, outlining, adjunct pictures) is reviewed. Predictions generated by the framework are consistently upheld.     

Textual and graphical refutations: Effects on conceptual change learning

Refutation text is potentially more effective than standard text for conceptual change. Learning from text and graphic is also potentially superior to learning from text alone. In two studies, we investigated the effectiveness of both a refutation text and a refutation graphic for promoting high school students’ conceptual change learning about season change, as well as their metacognitive awareness of conceptual conflict and knowledge revision. In both studies, participants were randomly assigned to one of four conditions: (1) standard text with standard graphic, (2) standard text with refutation graphic, (3) refutation text with standard graphic, or (4) refutation text with refutation graphic. Both studies had a pretest, immediate post-test, and delayed post-test design and involved students with an initial common misconception about the causes of season change. In Study 2, explicit relevance instructions to observe the important illustration were given to the participants. In both studies, refutation text with refutation graphic was not more beneficial than other instructional materials, either at immediate or delayed post-test. In Study 1, more stable conceptual change learning emerged in readers of the refutation text with standard graphic compared to readers in the control condition. In Study 2, readers of the standard text with refutation graphic performed as well as readers of the refutation text with standard graphic. In addition, more readers of the refutation text with either graphic showed metacognitive awareness of their knowledge change compared to readers in the control condition. Educational implications underline the importance of relevance instructions for guiding readers toward the graphic and of the design of text-graphic pairing to sustain knowledge revision.     

基于文本数据的数据挖掘算法研究

总结了数据挖掘的基本方法、文本数据挖掘的关键技术,讨论了文本挖掘的定义和文本分类的一些形式,并对文本数据的数据挖掘算法进行了研究。     

Effect of on-screen text on multimedia learning with native and foreign-accented narration

This study examined the impact of redundant on-screen text on learning from an animated PowerPoint presentation, narrated either by a native or a foreign-accented narrator, with no text, summary text, or full text. Participants completed retention and transfer tests and rated the cognitive load induced by the narration and the PowerPoint materials. With a native narrator, participants performed better on transfer with no text than summary text (redundancy effect). The foreign-accented narration was perceived to be more difficult to understand. Transfer performance was worse for accented than native narration with no text, replicating a voice effect. With a foreign-accented narrator, participants performed better on retention with full text than summary text. Full text facilitated decoding of the accented narration at the word level, but it did not facilitate deep processing for knowledge transfer. The results are discussed in the context of cognitive load and the cognitive theory of multimedia learning.     

Strategies to reduce the negative effects of spoken explanatory text on integrated tasks

Two experiments involving 125 grade-10 students learning about commerce investigated strategies to overcome the transient information effect caused by explanatory spoken text. The transient information effect occurs when learning is reduced as a result of information disappearing before the learner has time to adequately process it, or link it with new information. Spoken text, unless recorded or repeated in some fashion, is fleeting in nature and can be a major cause of transiency. The three strategies investigated, all theoretically expected to enhance learning, were: (a) replacing lengthy spoken text with written text (Experiments 1 and 2), (b) replacing lengthy continuous text with segmented text (Experiment 1), and (c) adding a diagram to lengthy spoken text (Experiment 2). In both experiments on tasks that required information to be integrated across segments, written text was found to be superior to spoken text. In Experiment 1 the expected advantage of segmented text in reducing transitory effects was not found. Compared with written continuous text the segmented spoken text strategy was inferior. Experiment 2 found that adding a diagram to spoken text was an advantage compared to spoken text alone consistent with a multimedia effect. Overall, the results suggest that spoken text is a cause of the transient information effect, which can be best avoided by substituting written text for spoken text on tasks that require integration of information.