基于RCE的云存储动态所有权管理数据去重方案

数据去重技术在云存储中应用广泛,通过存储数据的一个副本节省存储空间、降低通信开销。为了实现安全的数据去重复,收敛加密以及其很多变体相应被提出,然而,很多方案没有考虑所有权改变和所有权证明（PoW）问题。提出一种安全高效的动态所有权管理去重方案,通过更新组密钥对密钥密文进行重加密实现云用户所有权撤销后的管理问题,阻止撤销所有权的用户正确解密密文,构造了基于布隆过滤器的所有权证明,提出延迟更新策略进一步降低计算开销。分析和实验表明,该方案具有较小的开销,在动态所有权管理中是有效的。     

云存储中密文数据的客户端安全去重方案

云存储环境下,客户端数据去重能在本地进行文件重复性检测,有效地节约存储空间和网络带宽.然而,客户端去重仍面临着很多安全挑战.首先,由于将文件哈希值作为重复性检测的证据,攻击者很可能通过一个文件的哈希值获得整个文件;其次,为了保护数据隐私,收敛加密被广泛运用于数据去重方案,但是由于数据本身是可预测的,所以收敛加密仍不可避免地遭受暴力字典攻击.为了解决上述问题,本文首次利用盲签名构造了一个安全的密钥生成协议,通过引入一个密钥服务器,实现了对收敛密钥的二次加密,有效地预防了暴力字典攻击;并进一步提出了一个基于块密钥签名的拥有权证明方法,能够有效预防攻击者通过单一的哈希值来获取文件,并能同时实现对密文文件的文件级和块级去重.同时,安全分析表明本文方案在随机预言模型下是可证明安全的,并能够满足收敛密钥安全、标签一致性和抗暴力字典攻击等更多安全属性.此外,与现有方案相比,实验结果表明本文方案在文件上传和文件去重方面的计算开销相对较小.     

PoSW:novel secure deduplication scheme for collaborative cloud applications

In order to solve the problems of secure access and deduplication to the shared file in the cloud environment,a novel notion called proof of shared ownership (PoSW) was formalized,and a formal definition of the PoSW was given.Furthermore,a PoSW scheme and an enhanced version of that were proposed.In the PoSW scheme,secure shared file dispersal,convergent encryption and secret sharing algorithm were employed to transform the shared file realize the sharing and authorization for the shared file,and then a novel challenge-response protocol was proposed to achieve the proof of shared ownership and the foundation for the secure deduplication of the shared file was provided.An enhanced PoSW scheme was designed to improve the availability and reliability for different kinds of the shared files by introducing the multi-cloud server providers and using the strategies of both data duplication and secret file dispersal.Security analysis and performance evaluation show the security and efficiency of the proposed scheme.     

可穿戴设备归属权限转换协议研究

针对可穿戴环境下的信息安面临的巨大挑战,本文在考虑公共环境下可穿戴设备的用户转换的情景下,设计了一个适合可穿戴环境的用户权限转换协议框架,并对协议进行了详细设计.通过理论和实践分析得出,该协议可以满足可穿戴设备对安全性和实用性的要求,可以保障转换过程中的数据安全.     

Is Homeownership the Answer? Housing Tenure and Indigenous Australians in Remote (and Settled) Areas

This paper examines the relevance of recently floated policy ideas for extending homeownership to remote Aboriginal Australians. It argues that while the housing tenure system in more densely settled Australia is dominated by homeownership, this is not, and cannot realistically be expected to be, the case in remote areas. The paper uses data from the 2001 Census, organized by remoteness geography, to demonstrate the different character of the housing tenure system in remote Australia. The paper argues that homeownership in remote Aboriginal communities is a somewhat unrealistic policy goal, given the underlying income and employment status of Indigenous people in these communities. The paper also argues that there are better measures of Indigenous housing need and disadvantage in Australia than low homeownership rates. It briefly reports on one past failed experiment in Queensland to introduce homeownership to a remote Aboriginal community.     

西安市城中村改造研究

以西安市“城中村”为研究对象，介绍了西安市城中村的现状，分析了“城中村”形成的原因及面临的问题，从社会学、经济学角度出发，探讨了“城中村”改造的对策，以使其与城市总体发展相互适应、相互协调，实现发展的可持续性。     

Housing location choices of the poor: does access to jobs matter?

Abstract

This research investigates whether access to jobs affects poor households’ residential location choices using data from individual households in the Chicago Metropolitan Area. Our results, based on discrete choice models, show that the effects of job accessibility on household location choices are contingent upon households’ automobile ownership and employment status. Places with higher job accessibility by public transit mode are more likely to attract poor households that do not own cars but have at least one employed worker or one labour force participant, while job accessibility by automobile travel mode has no positive effect on the location choices of poor households who own automobiles. The results stress the importance of job accessibility for those poor households with limited transportation mobility but strong needs for access to jobs.     

英国提高保障性住房项目可持续性的策略及其启示

作为最早针对住房问题实施住房保障政策的国家,英国不仅成功地解决了住房问题,而且还实现了保障性住房的可持续发展,其成功经验值得我国借鉴。系统地总结了英国在提高保障性住房项目社会可持续性、经济可持续性和生态可持续性方面的策略,包括建立紧密协作的管理队伍、多主体参与保障性住房的供给、设计和建造可持续的保障性住房等。并根据我国保障性住房项目的发展现状和存在的不足,提出对我国保障性住房项目可持续发展的启示。     

Research progress on secure data deduplication in cloud

In order to improve the efficiency of cloud storage and save the communication bandwidth, a deduplication mechanism for multi-duplicate of the same data in cloud environment was needed. However, the implement of the secure data deduplication was seriously hindered by the ciphertext in cloud. This issue has quickly aroused wide attention of academia and industry, and became a research hotspot. From a security standpoint, firstly the primary cause and the main challenges of secure data deduplication in cloud environment was analyzed, and then the deduplication system model as well as its security model was described. Furthermore, focusing on the realization mechanism of secure data deduplica-tion, the thorough analyses were carried on and reviews for the related research works in recent years from content-based encryption, proof of ownership and privacy protection for secure deduplication, then the advantages and common prob-lems of various key technologies and methods were summed up. Finally, the future research directions and development trends on secure data deduplication in cloud was given.     

两类样本上市公司的股权结构与绩效评估

为研究上市公司股权结构与绩效之间的关系,基于计量经济学回归模型,以民营及含QFII概念的两类上市公司为样本,得到了回归参数的两类最小二乘估计,检验了方程和参数的显著性．结果表明,民营上市公司绩效对管理层持股比例产生不同影响源于“一股独大”现象,而含QFII概念的上市公司与国内学者所选传统行业样本公司的结论是相似的．