Uncertainty-Based Trust Modeling And Its Management Of Grid Computing

The grid research originates from the demand of modern science for high performance computing, massive data processing and sharing of expensive scientific resources flexibly. The essence of grid is to achieve the large-scale and multi-faceted collaborative sharing of resource and virtualization, in order to attain the objective of accelerating the program process, developing innovative application based on virtual organizations. The resulting problem is how does grid improve the quality of shared resources as far as the resource owners keeping control of their own resources, and maintain the confidentiality to others? To this end, trust and its management is growing in importance. In fact, trust mechanism has always been in support of the collaboration among human and organizations. Since trust is the basis of human interaction offline, it is also bound to be the foundation for online interaction. Which leads to the conclusion of that, trust has become a new metric for grid. People need the ability to transfer the human trust reasoning into the distributed computing system, such as grid.This dissertation starts with the development vein of information security technology, firstly analyses the transition of information security paradigm from security to trustworthiness, and then the inevitable trend for the new idea of Trusted Computing, whose core is trust theory and behaviors monitor. The attentive focus is the subjective credibility of interactive entity itself in applicable level, i.e., to support Trusted Computing based on effective trust evaluation and management mechanisms. The fundamental research of trust theory is taken for centralization, and the methodology we adopt is the combination of theoretical analysis with applied research, the issue we focused on is trust management and decision-making under the virtual integration platform that compromises the merits of grid computing and P2P computing. Comparing with the State of the art survey on trust and security in Grid computing home and abroad, the main research contents and innovation achievements of this dissertation are as follows:â… .The overall survey on the demand for security and trust management, and the state of the art of it is given under Grid environment, then the necessity and feasibility of using trust mechanism to resolve the issue of grid security is demonstrated.â…¡. The dialectical relation between trust and security is made a clear, from the point of view of trust definition and basic property that comes from social and computer sciences. The virtual worlds that composed of computer network and distributed system were treated as the extension of human interaction, and then trust mechanism can be applied to solve grid security issues. The important role of social attribute of trust was emphasized; it is the basis for all trust modeling. The main distinction between our research and others that we surveyed is the characteristics of excessive formalization, due to the classical mathematics they used.â…¢. The unascertained mathematics that can deal with multiple uncertainties is used to model grid trust for the first time. We focus on the behavior-based (historical interactive record) trust establishment, evaluation and decision-making, and distinguish uncertainty caused by behavior factor or status ones. All possible value intervals and their corresponding trust degree are used to cope with uncertainty. In the course of trust evaluation, not only the evaluation results can be quantified, but also all the information and the subjective trust degree can be shown. Uncertainty is the main line during the whole course of trust modeling, evaluation and decision-making.â…£. The grid trust management framework(GTMF) is separated from the specific application logic by means of customization grid service. It was trust community and trust management infrastructure that we rely on to realize the effective trust management. Within this framework, security is achieved at a higher level, while the quality of grid non-trivial services can be ensured at the same time. The main design emphasis of GTMF is to raise the efficiency of trust based decision-making by means of the overall evaluation that relying on unascertained measurement, rather than blindly chasing the precision computing of (global) trust value.â…¤. A grid trust management prototype is successfully brought about in this thesis. The actual effect of GTMF was simulated by experiment, and the results show that, the proposed method is not only workable, but also can provide operable and overall consideration practice basis for such issues as grid resources choice, authorization decision-making and access control etc. other local that can be integrated and operable in accordance with the practice.The result of research in this dissertation has made valuable contributions to the trust and security issues in Web-based distributed environment. And the introduction of unascertained mathematics has brought about a new way for trust modeling and evaluation, which is useful to both the theory and practice of study further.