一种支持复杂关系查询的图存储系统

大数据时代,数据间的高相关性为大数据带来了重要价值,"图"这一抽象数据结构能够很好地表示数据间的关系.复杂图数据具有数据规模大、建模需求多、关系查询复杂等特点,为图存储系统的构建带来挑战.提出了一种支持时间演化和数据溯源的图数据模型,形式化定义了数据结构、数据操作和数据完整性约束,为大规模图数据存储系统的实现奠定了理论基础;实现了一个支持复杂数据查询的图存储系统,为分析挖掘图数据的巨大价值提供了底层基础设施技术支撑.通过实验对系统的存储、入库、查询等能力进行了效果评估,结果表明所提方法有效可行.

Global Memory Net and the development of digital image information management system: Experience and practice

Global Memory Net (GMNet) is intended to be an effective gateway to the world cultural, historical, and heritage image collections from selected academic educational and research partners in the world. Much of these unique collections of great value to education and research are not currently accessible due to distance, form, and technical barriers. This project is to find new ways to enable users to access and exploit these significant research collections via global network. As GMNet is ending its first 5-year phase in October 2005, it has contributed substantially to the community building in digital library development by ac- commodating numerous collaborators and technical staff from various parts of the world to spend 3 to 5 months as a full-member of the GMNet team in Boston. They have come from different parts of China—such as Sichuan, Hainan, Shanghai and Xi’an; Croatia; and Hanoi, Vietnam. In addition to contribute to the overall system development and enhancement of system function- alities, they have brought valuable sample image collections of their own institutions/countries, and actually developed prototype collections as a part of GMNet. This paper describes the exciting and productive experience of the first of this visiting research group in developing the GMNet’s Version 2.0 PHP-based system under Prof. Chen’s overall supervision. It also describes both the system’s technical level structure—user/Web-based application/data, and complex functionalities with multi-collection, multi-lingual, multi-modal searching capabilities; system management capabilities; as well as provisions for user uploads and retrieval for our own projects. This Version 2.0 system is built on the Linux/Apache/PHP/MySQL platform. What is described in this paper is an actual case which has formed a base for further new development by others in the research group. It demonstrates fully the value of the synergistic collaboration among global partners for universal digital library development. More information can be found in http://www.memorynet.org/.

Content Addressable Storage Optimization for Desktop Virtualization Based Disaster Backup Storage System

This paper proposes a content addres sable storage optimization method, VDeskCAS, for desktop virtualization storage based disaster backup storage system. The method implements a blocklevel storage optimization, by employing the algorithms of chunking image file into blocks, the blockffmger calculation and the block dedup li cation. A File system in Use Space （FUSE） based storage process for VDeskCAS is also introduced which optimizes current direct storage to suit our content addressable storage. An interface level modification makes our system easy to extend. Experiments on virtual desktop image files and normal files verify the effectiveness of our method and above 60% storage volume decrease is a chieved for Red Hat Enterprise Linux image files. Key words： disaster backup; desktop virtualization; storage optimization; content addressable storage

New mode of universal access and Global Memory Net

In this digital era, we have witness the exciting convergence of content, technology, and global collaboration in the development of digital libraries. The mode of universal access for information seeking and knowledge acquisition differs greatly fi＇om the traditional ways. From the information resources point of views, the old model of“owning” a collection has given way to “sharing,” and the new emphases have shifted fi＇om possessing large “physical libraries” to “virtual libraries” digitally distributed all over the world. “Universal access” has taken on a very different meaning when one has the ability to share invaluable resources through the use of cutting edge technologies. The author has experienced much of these transformations through her own R＆D activities-from the creation of interactive videodisc and multimedia CD on the First Emperor of China＇s terracotta warriors and horses in the 1980s and 1990s to leading a current international digital library project, Global Memory Net （GMNet）, supported by the US National Science Foundation. In presenting her vision for linking world digital resources together for universal access, she will share with the audience the latest development of Global Memory Net.

Research on the Security of the United Storage Network Based on NAS

A multi-user view file system (MUVFS) and a security scheme are developed to improve the security of the united storage network (USN) that integrates a network attached storage (NAS) and a storage area network (SAN). The MUVFS offers a storage volume view for each authorized user who can access only the data in his own storage volume, the security scheme enables all users to encrypt and decrypt the data of their own storage view at client-side, and the USN server needs only to check the users’ identities and the data’s integrity. Experiments were performed to compare the sequential read, write and read/write rates of NFS+MUVFS+secure_module with those of NFS. The results indicate that the security of the USN is improved greatly with little influence on the system performance when the MUVFS and the security scheme are integrated into it.

ImgFS： a transparent cryptography for stored images using a filesystem in userspace

Real-time encryption and decryption of digital images stored on end-user devices is a challenging task due to the inherent features of the images. Traditional software encryption applications generally suffered from the expense of user con- venience, performance efficiency, and the level of security provided. To overcome these limitations, the concept of transparent encryption has been proposed. This type of encryption mechanism can be implemented most efficiently with kernel file systems. However, this approach has some disadvantages since developing a new file system and attaching it in the kernel level requires a deep understanding of the kernel internal data structure. A filesystem in userspace （FUSE） can be used to bridge the gap. Never- theless, ctwrent implementations of cryptographic FUSE-based file systems suffered from several weaknesses that make them less than ideal for deployment. This paper describes the design and implementation of ImgFS, a fully transparent cryptographic file system that resides on user space. ImgFS can provide a sophisticated way to access, manage, and monitor all encryption and key management operations for image files stored on the local disk without any interaction from the user. The development of ImgFS has managed to solve weaknesses that have been identified on cryptographic FUSE-based implementations. Experiments were carried out to measure the performance of ImgFS over image files＇ read and write against the cryptographic service, and the results indicated that while ImgFS has managed to provide higher level of security and transparency, its performance was competitive with other established cryptographic FUSE-based schemes of high performance.