基于混沌序列的改进LSB隐写算法

LSB替换算法会导致含密图像的统计不对称性、直方图异常等现象,给LSB隐写分析留下可乘之机。其改进方法LSB匹配隐写算法能有效弥补此缺点,但该方法是非盲提取技术,通信时增加了额外开销。本文用Logistic双混沌系统分别对秘密图像进行置乱处理和嵌入位面的随机选取,将替换和匹配的思想相结合,有效克服了含密图像统计不对称性、直方图异常等现象,具有与LSB匹配隐写等效的对抗LSB隐写分析的能力,而且是一种盲提取算法。实验表明,该算法是高效的,安全的。     

基于局部相关的图像隐写方法研究

提出了一种新的图像隐写方法。利用载体图像和秘密图像之间的局部相关性,将秘密图像嵌入到载体图像当中。实验结果表明,该方法能够嵌入较多信息和保持良好的载密图像质量,并且可从载密图像中完全提取出秘密信息。     

基于游程统计和Walsh谱能量分布的调色板图像隐写分析

提出一种基于游程统计和Walsh谱能量分布的调色板图像隐写分析方法,利用调色板颜色的奇偶值(parity value,P值)构造P值图像,通过游程统计和Walsh变换提取出46维特征,并用校准技术削弱载体图像差异对分析统计量的干扰.实验表明,该方法适用于EzStego、分量和以及最佳奇偶隐写等调色板图像隐写算法,比奇异颜色分析准确.     

基于特征码的Imagehide与JPEGX图像隐藏信息检测以及提取

信息隐藏技术利用载体中存在的冗余信息来隐藏秘密对象,以隐藏秘密信息的存在。隐写术是信息隐藏的一个重要分支。隐写分析是通过对隐密对象的分析,对秘密信息进行检测及破解的技术。本文针对Imagehide与JPEGX两种网上常见的隐写工具,从分析特征码出发,揭示了检测和提取秘密信息的方法,并进行了实验,取得了较好的结果,证明了该方法的有效性。     

经典音频隐写算法综述

音频隐写技术作为信息隐藏的一个重要分支,近些年来越来越受到学术界的关注。本文对LSB隐写算法、回声隐写算法、扩频隐写算法及压缩域隐写算法等几种经典音频隐写算法进行总结和阐述。     

基于二值图像的信息隐藏与分析研究

图像信息隐藏是近些年快速发展起来的一种新型信息安全技术,本文在对已有的二值图像隐写方法比较分析基础上,设计了一种通过二值原始图像与隐写图像和隐写图像与二次隐写图像的游程特性变化差值不同,分类确定相应阈值来检测隐秘信息的统计分析方法。实验结果证明这种方法能够成地检测出分块跳转中心像素和分块非跳转中心像素的信息隐藏,并有很高的检测率,实现了对二值图像隐写的盲检测。     

基于混沌序列的LSB水印算法研究

针对LSB算法隐秘性的不足,本文提出一种基于混沌序列的LSB数字水印算法。该算法首先二值化水印图像,其次采用混沌序列置乱该水印图像,最后嵌入目标图像像素最低位。实验结果表明,对比其他水印算法,该算法具有良好的鲁棒性和视觉隐藏性。     

一种直方图失真小的JPEG图像隐写方法

给出了一种JPEG图像的隐写方法,将部分零系数用于矩阵编码来负载秘密信息,不仅提高了信息嵌入容量,还有效减小了直方图失真。将每个8＊8小块中,除直流系数以外的前31个量化系数用于隐藏秘密信息。通过对80幅256＊256灰度图像进行实验,结果表明对于一般的自然图像该算法可以有效地控制直方图失真。     

基于Arnold变换的二值图像算法

在数字水印方案中,单纯地用各种信息隐藏算法对秘密信息进行加密是不安全的,因为攻击者只要破解了加密算法,就可能直接提取出秘密信息。针对这一点,提出在秘密信息隐藏之前,先对其进行置乱处理,使其失去本身原有的面目,再隐藏到载体中,以确保信息的安全性。以Fibonacci变换和Arnold变换的实验结果阐述了数字图像置乱方法在数字水印中的作用,并提了出一种利用Arnold反变换恢复图像的方法。     

一种基于信息隐藏的安全二维码技术

本文提出了一种基于信息隐藏技术的安全二维码算法,该算法通过改变二维码中黑白图像块像素行程的奇偶性来嵌入信息。通过嵌入信息改变二维码的形态,有效保护二维码的内容。嵌入的信息可以被正确提取,提取信息后载体二维码可以无损的恢复。该算法在起到保护二维内容的同时还实现了一种可逆隐藏方案,具有广泛用途。实验证明该算法运算速度快,能有效地保护和恢复二维码信息。     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence     

Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels

<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese     

More than Skin Deep – Understand Skin Biology by Means of Dermatogenomics

<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.