Yuexuan Wang

The study on simulation grid technology for equipment resource sharing system

It is difficult to realize equipment resources sharing on network. Based on grid and simulation modeling technique, simulation-grid architecture is presented. Simulation models of sharing equipments are established in grid. Manipulating and optimally scheduling remote equipments are realized by operating the simulation models in simulation-grid system. The proposed architecture provides a method to equipment resources sharing and management on network and would be widely used.

Ensuring secure and robust grid applications – from a formal method point of view

Ensuring the reliability and robustness of complex scientific grid applications is a critical issue for managing and sharing expensive scientific instruments. However, guaranteeing the correct processing of grid applications under all circumstances is difficult and not fully addressed by existing grid infrastructure. Hidden flaws in the applications including unexpected internal behaviors, dissatisfaction of real-time constraints, incompatibility in service interactions, etc may lead to subtle failures in grid systems. This work tries to enhance the trustworthiness of grid applications by investigating existing formal techniques and their extensions. A formal framework based on extensions of Pi calculus is proposed which also integrates formal techniques of model checking and bisimulation analysis to enable the reasoning of grid applications from three perspectives: data, time and behavior. In addition, both application examples and our current implementation architecture are also concluded.

Research on Equipment Resource Scheduling in Grids

In order to resolve equipment resources scheduling problem in grid we develop an equipment resource scheduling system with the equipment grid portal and scheduler including scheduling algorithm, information service and its architecture. The proposed technique provides a method to equipment resources sharing and management on network and will be widely used.

Study on equipment interoperation chain model in grid environment

Scientific collaboration has emerged as an important tool for getting forefront research results by interoperating geographically distributed scientific equipment to solve complicated scientific problems. Grid technologies offer effective strategies to achieve this ambitious goal. However, more capabilities are required in the context of Equipment Grid due to the complexity of collaboration between equipment resources. In this paper an interesting equipment interoperation chain model is proposed. Equipment resources are organized into equipment pools, based on which the interoperation chain of equipment is built. The performance is discussed by means of several theoretical tools like Petri Net and π-Calculus from the different viewpoint of users. The structure of interoperation chain is proven highly efficient and feasible. Finally we analyze the prospective direction and challenges in this field.

Predictive Admission Control Algorithm for Advance Reservation in Equipment Grid

Experiments submitted to equipment grid have quality of service (QoS) requirements, and advance reservation is used to satisfy such requirements. Due to the dynamic behaviors and fluctuations of resources in equipment grid, some previously accepted advance reservations are unable to be fulfilled. In this paper, we present a predictive admission control algorithm to decide whether new advance reservation requests can be accepted according to their QoS requirements and prediction of future resource utilization. Historical data are used in this algorithm to predict future status of resources. Experiments demonstrate that our algorithm can reduce the number of accepted advance reservations that fail to be fulfilled and keep the resource utilization ratio at an acceptable level.

Dynamic Service Composition: a Collaborative Resource Sharing Framework for Equipment Grid

To get the distributed and autonomous equipments in equipment grid(EG) work collaboratively to serve users as a supper virtual equip, dynamic service composition (DSC), a five-layered implemental framework is put forward. Via solving the sub- problems in each layer, simple services from local equipments are combined into complex ones to realize the collaborative sharing. And an EG prototype has been established based on DSC.

Study on π-calculus based equipment grid service chain model

The development of modern science requires the equipment grid to provide a scientific collaboration research platform, which can realize remote collaboration and sharing with the key instruments and equipment in wide areas. The reliability and high efficiency of a grid service chain model are key points in creation of a grid equipment system. The π-calculus as powerful process algebra has a specific advantage in modeling and testing the grid service chain model. This research investigates and improves a theoretical analysis and algorithm framework for the modeling, correctness checking and analysis of the π-calculus based equipment grid service chain model. It also studies on the analysis of its logistic structure and flexible modeling for the equipment grid. It would be beneficial to open up a new space in the theoretical and applied research on grid technology and formal methodology based on cross-disciplinary cooperation.

Scheduling Remote Access to Scientific Instruments in Cyberinfrastructure for Education and Research

While a grid represents a computing infrastructure for cross domain sharing of computational resources, the cyberinfrastructure, proposed by the US NSF Blue - Ribbon advisory panel, is expected to revolutionizing science and engineering by including more computer integrated resources, e.g. telescopes and observatories. As a part of the China national cyberinfrastructure for education and research, resource sharing of expensive scientific instruments is discussed in this work. A layered model of instrument pools is introduced and the process from submitting a job to instrument pools to obtaining results is analyzed. Fuzzy random scheduling algorithms are proposed in instrument pools when a job is submitted to one of instruments within a pool. The randomness lies in the probability which instrument could be chosen for an experiment and the fuzziness origins from vagueness of users feedback opinions on experimental results. Users feedback information is utilized to improve overall quality of service (QoS) of an instrument cyberinfrastructure. Several algorithms are provided to increase utilization of instruments providing higher QoS and decrease utilization of those with poor QoS. This is demonstrated in details using quantitative simulation results included in this paper.

Service Provenance based Abstraction of Grid Application Knowledge

Grid infrastructure is becoming a platform for the design, implementation and execution of various scientific experiments. Consequently it forms a hidden storehouse of application knowledge about historically how a grid application was designed and performed (e.g. the used approaches, required data, etc). This work addresses the issue of abstracting the application knowledge in grid based on service provenances. Our method is composed by the steps of providing a formal description for detailed service provenances; deducing the set of service provenance descriptions that indicates how a desired application result can be obtained; abstracting and visualizing the deduced result to facilitate the understanding, sharing and reuse of corresponding application knowledge. The implementation status of our method is also reported.

Aspect Oriented Region Analysis for Efficient Grid Application Reasoning

With the development of grid techniques and the growing complexity of grid applications, reasoning the temporal properties of grid application to ensure its reliability is becoming more and more critical. In this work, two decomposition approaches are proposed to improve the performance of the temporal reasoning of complex grid applications. The proposed approaches are implemented in our GridPiAnalyzer for equipment grid. Results show that our approach can reduce both CPU time and memory cost compared to using traditional formal verification algorithm alone due to the exponential reduction of system state space