Web服务作为一种新型的Web应用模式,近年来得到了迅速的发展.如何动态地把现存的各种Web服务整合起来以形成新的、满足不同用户需求的、增值的复杂服务已成为新的应用需求和研究热点.针对现有服务聚合中服务选择技术的不足,提出了一种...Web服务作为一种新型的Web应用模式,近年来得到了迅速的发展.如何动态地把现存的各种Web服务整合起来以形成新的、满足不同用户需求的、增值的复杂服务已成为新的应用需求和研究热点.针对现有服务聚合中服务选择技术的不足,提出了一种解决服务聚合中服务动态选择QoS全局最优化问题的实现算法GODSS(global optimal of dynamic Web services selection).算法的主要思想是把服务动态选择全局最优化问题转化为一个带QoS约束的多目标服务组合优化问题,利用多目标遗传算法的智能优化原理,通过同时优化多个目标函数,最终产生一组满足约束条件的Pareto优化服务聚合流程集.理论分析和实验结果说明了算法的可行性和有效性.展开更多
The high penetration of distributed renewable energy raises a higher concern for the safe and economic operation of the smart grid. Distributed batteries equipped in demand-side can not only contribute to the reliabil...The high penetration of distributed renewable energy raises a higher concern for the safe and economic operation of the smart grid. Distributed batteries equipped in demand-side can not only contribute to the reliability and security of the grid, but also make profits by participating in the electricity market, especially when distributed batteries are combined and operated by an aggregator.Considering the well-operated mechanism of performance based regulation(PBR) in the U.S. electricity market, it becomes increasingly lucrative for batteries to participate not only in energy markets for energy arbitrage, but also in ancillary service markets to provide regulation and peakload shaving services. In this study, distributed batteries are operated and coordinated by the aggregator, which simultaneously submits offers to the energy and the ancillary service markets as an individual entity. An optimaldecision model is formulated for the aggregator to determine the operation and bidding strategy for the distributed batteries by considering the characteristics of batteries,including the terms of capacity, efficiency and degradation cost. Finally, a numerical case is conducted to evaluate the benefits of the decision model.展开更多
Based on the deficiency of time convergence and variability of Web services selection for services composition supporting cross-enterprises collaboration,an algorithm QCDSS(QoS constraints of dynamic Web services sele...Based on the deficiency of time convergence and variability of Web services selection for services composition supporting cross-enterprises collaboration,an algorithm QCDSS(QoS constraints of dynamic Web services selection)to resolve dynamic Web services selection with QoS global optimal path,was proposed.The essence of the algorithm was that the problem of dynamic Web services selection with QoS global optimal path was transformed into a multi-objective services composition optimization problem with QoS constraints.The operations of the cross and mutation in genetic algorithm were brought into PSOA(particle swarm optimization algorithm),forming an improved algorithm(IPSOA)to solve the QoS global optimal problem.Theoretical analysis and experimental results indicate that the algorithm can better satisfy the time convergence requirement for Web services composition supporting cross-enterprises collaboration than the traditional algorithms.展开更多
面对复杂多变的电力市场环境,水电站群发电调度决策支持系统采用基于面向服务架构(SOA)的工作流程管理(Business Process Management,BPM)方案,通过业务流程建模、执行和重组,充分利用Web服务的优点,构建具有业务流程自动化和可重构能...面对复杂多变的电力市场环境,水电站群发电调度决策支持系统采用基于面向服务架构(SOA)的工作流程管理(Business Process Management,BPM)方案,通过业务流程建模、执行和重组,充分利用Web服务的优点,构建具有业务流程自动化和可重构能力的快速适应性系统,适应市场需求变化并快速响应变化。该方案使系统更易于改进和扩展,实现软件系统结构上的敏捷性。展开更多
In the research of service composition,it demands efficient algorithms that not only retrieve correct service compositions automatically from thousands of services but also satisfy the quality requirements of differen...In the research of service composition,it demands efficient algorithms that not only retrieve correct service compositions automatically from thousands of services but also satisfy the quality requirements of different service users.However,most approaches treat these two aspects as two separate problems,automatic service composition and service selection.Although the latest researches realize the restriction of this separate view and some specific methods are proposed,they still suffer from serious limitations in scalability and accuracy when addressing both requirements simultaneously.In order to cope with these limitations and efficiently solve the combined problem which is known as QoS-aware or QoS-driven automatic service composition problem,we propose a new graph search problem,single-source optimal directed acyclic graphs （DAGs）,for the first time.This novel single-source optimal DAGs （SSOD） problem is similar to,but more general than the classical single-source shortest paths （SSSP） problem.In this paper,a new graph model of SSOD problem is proposed and a Sim-Dijkstra algorithm is presented to address the SSOD problem with the time complexity of O（n log n ＋ m） （n and m are the number of nodes and edges in the graph respectively）,and the proofs of its soundness.It is also directly applied to solve the QoS-aware automatic service composition problem,and a service composition tool named QSynth is implemented.Evaluations show that Sim-Dijkstra algorithm achieves superior scalability and efficiency with respect to a large variety of composition scenarios,even more efficient than our worklist algorithm that won the performance championship of Web Services Challenge 2009.展开更多
基金Supported by the National HighTech Research and Development Plan of China under Grant Nos.2002AA1340102002AA1340202003AA135110(国家高技术研究发展计划(863))
文摘Web服务作为一种新型的Web应用模式,近年来得到了迅速的发展.如何动态地把现存的各种Web服务整合起来以形成新的、满足不同用户需求的、增值的复杂服务已成为新的应用需求和研究热点.针对现有服务聚合中服务选择技术的不足,提出了一种解决服务聚合中服务动态选择QoS全局最优化问题的实现算法GODSS(global optimal of dynamic Web services selection).算法的主要思想是把服务动态选择全局最优化问题转化为一个带QoS约束的多目标服务组合优化问题,利用多目标遗传算法的智能优化原理,通过同时优化多个目标函数,最终产生一组满足约束条件的Pareto优化服务聚合流程集.理论分析和实验结果说明了算法的可行性和有效性.
基金supported by Major International (Regional) Joint Research Project of National Natural Science Foundation of China (No. 51620105007)Scientific Research Project of Guangdong Electric Power Research Institute
文摘The high penetration of distributed renewable energy raises a higher concern for the safe and economic operation of the smart grid. Distributed batteries equipped in demand-side can not only contribute to the reliability and security of the grid, but also make profits by participating in the electricity market, especially when distributed batteries are combined and operated by an aggregator.Considering the well-operated mechanism of performance based regulation(PBR) in the U.S. electricity market, it becomes increasingly lucrative for batteries to participate not only in energy markets for energy arbitrage, but also in ancillary service markets to provide regulation and peakload shaving services. In this study, distributed batteries are operated and coordinated by the aggregator, which simultaneously submits offers to the energy and the ancillary service markets as an individual entity. An optimaldecision model is formulated for the aggregator to determine the operation and bidding strategy for the distributed batteries by considering the characteristics of batteries,including the terms of capacity, efficiency and degradation cost. Finally, a numerical case is conducted to evaluate the benefits of the decision model.
基金Project(70631004)supported by the Key Project of the National Natural Science Foundation of ChinaProject(20080440988)supported by the Postdoctoral Science Foundation of China+1 种基金Project(09JJ4030)supported by the Natural Science Foundation of Hunan Province,ChinaProject supported by the Postdoctoral Science Foundation of Central South University,China
文摘Based on the deficiency of time convergence and variability of Web services selection for services composition supporting cross-enterprises collaboration,an algorithm QCDSS(QoS constraints of dynamic Web services selection)to resolve dynamic Web services selection with QoS global optimal path,was proposed.The essence of the algorithm was that the problem of dynamic Web services selection with QoS global optimal path was transformed into a multi-objective services composition optimization problem with QoS constraints.The operations of the cross and mutation in genetic algorithm were brought into PSOA(particle swarm optimization algorithm),forming an improved algorithm(IPSOA)to solve the QoS global optimal problem.Theoretical analysis and experimental results indicate that the algorithm can better satisfy the time convergence requirement for Web services composition supporting cross-enterprises collaboration than the traditional algorithms.
文摘面对复杂多变的电力市场环境,水电站群发电调度决策支持系统采用基于面向服务架构(SOA)的工作流程管理(Business Process Management,BPM)方案,通过业务流程建模、执行和重组,充分利用Web服务的优点,构建具有业务流程自动化和可重构能力的快速适应性系统,适应市场需求变化并快速响应变化。该方案使系统更易于改进和扩展,实现软件系统结构上的敏捷性。
基金Supported by the National Basic Research 973 Program of China under Grant No.2007CB-310805the National Natural Science Foundation of China under Grant No.61070027+2 种基金the Beijing Natural Science Foundation project under Grant No.4092043the Scienceand Technology Project of State Grid Information&Telecommunication Company Ltd.under Grant No.SGIT[2010]449the Planned Science and Technology Project of Guangdong Province,China under Grant No.2010B050100009
文摘In the research of service composition,it demands efficient algorithms that not only retrieve correct service compositions automatically from thousands of services but also satisfy the quality requirements of different service users.However,most approaches treat these two aspects as two separate problems,automatic service composition and service selection.Although the latest researches realize the restriction of this separate view and some specific methods are proposed,they still suffer from serious limitations in scalability and accuracy when addressing both requirements simultaneously.In order to cope with these limitations and efficiently solve the combined problem which is known as QoS-aware or QoS-driven automatic service composition problem,we propose a new graph search problem,single-source optimal directed acyclic graphs （DAGs）,for the first time.This novel single-source optimal DAGs （SSOD） problem is similar to,but more general than the classical single-source shortest paths （SSSP） problem.In this paper,a new graph model of SSOD problem is proposed and a Sim-Dijkstra algorithm is presented to address the SSOD problem with the time complexity of O（n log n ＋ m） （n and m are the number of nodes and edges in the graph respectively）,and the proofs of its soundness.It is also directly applied to solve the QoS-aware automatic service composition problem,and a service composition tool named QSynth is implemented.Evaluations show that Sim-Dijkstra algorithm achieves superior scalability and efficiency with respect to a large variety of composition scenarios,even more efficient than our worklist algorithm that won the performance championship of Web Services Challenge 2009.
