Adaptive Trust Management Framework in P2P Grid Computing

In P2P Grid computing systems, the authorization decision is often tackled by two different trust management methods： policy-based approach, where authorization are built on logical rules and verifiable properties encoded in signed credentials, and reputation-based approach, based on collecting, aggregating and disseminating reputation among the peers. However, the overhead caused by proof of compliance on authorization and the absence of certifying authorities may negate the strong and objective security advantages of policy-based approach, whilst vagueness, complexity and inaccurate characterization caused by reputation evolution may eliminate the quantitative and flexible advantages of reputation-based approach. We propose an adaptive trust management framework, which combines the merit of policy proof and reputation evolution such that authorization is aware of not only the strong and objective security traits, but also the calculability and the availability security traits. Finally, the framework of system is proposed.

A Survey of Web Information System and Applications

The fourth international conference on Web information systems and applications （WISA 2007） has received 409 submissions and has accepted 37 papers for publication in this issue. The papers cover broad research areas, including Web mining and data warehouse, Deep Web and Web integration, P2P networks, text processing and information retrieval, as well as Web Services and Web infrastructure. After briefly introducing the WISA conference, the survey outlines the current activities and future trends concerning Web information systems and applications based on the papers accepted for publication.

Hybrid Collaborative Management Ring on Mobile Multi-agent for Cloud-P2P

In order to fully utilize all potential available network resources and make the interoperability of systems possible, we propose to integrate cloud computing and peer-to-peer （P2P） computing environments together. We utilize the mobile multi-agent technology to construct an effective hierarchical integration model named Cloud-P2P. As the original management mechanisms for traditional cloud computing and P2P computing systems are no longer applicable to Cloud-P2P, we propose a novel hybrid collaborative management ring based on mobile multi-agent in order to ensure the efficiency and success rate of task implementation in the Cloud- P2P environment. This mechanism needs to divide the system into core ring, cloud inner rings and several peer rings. In each ring, every node is in collaboration with its neighbor nodes with multi-agent, or uses mobile agent moving from node to node with string or parallel methods to monitor the statuses and performances of all nodes, in order to avoid problems of performance bottleneck and single point failure. This paper analyses the node conditions of cloud computing and P2P computing environments in-depth, then elaborates on Cloud-P2P and the hybrid collaborative management ring based on mobile multi-agent （HCMRMMA）. After that, the construction method of the network ring topology for Cloud-P2P is introduced. Finally, experimental results and performance analysis of HCMRMMA are presented.

P2P network traffic control mechanism based on global evaluation values

Peer-to-peer（P2P） computing technology has been widely used on the Internet to exchange data. However, it occupies much network bandwidth, and thus greatly influences traditional business on the Internet. Besides, problems about free-riders and ＇tragedy of the commons＇ in the P2P environment estrange from it P2P users who constantly contribute to the network with quality resources. This article proposes a new P2P network traffic control mechanism based on global evaluation values. It aims to help individual users to avoid peak traffic time as much as possible, ease network congestion and protect traditional business on the Internet, as well as differentiating priority grades of peers according to their contributions and stimulating them to share their valuable resources actively. This article first analyzes the current state of network traffic, and then elaborates on P2P network traffic control policies and proposes the peer＇s priority level differentiation mechanism based on global evaluation values. Finally, after the testing results and analysis of the proposed P2P network traffic control mechanism are discussed, conclusions are drawn.

Database Research： Achievements and Challenges

Database system is the infrastructure of the modern information system. The R＆D in the database system and its technologies is one of the important research topics in the field. The database R＆D in China took off later but it moves along by giant steps. This report presents the achievements Renmin University of China （RUC） has made in the past 25 years and at the same time addresses some of the research projects we, RUC, are currently working on. The National Natural Science Foundation of China supports and initiates most of our research projects and these successfully conducted projects have produced fruitful results.