Web service composition is a low cost and efficient way to leverage the existing resource and implementation.In current Web service composition implementations,the issue of how to define the role for a new composite W...Web service composition is a low cost and efficient way to leverage the existing resource and implementation.In current Web service composition implementations,the issue of how to define the role for a new composite Web service has been little addressed.Adjusting the access control policy for a new composite Web service always causes substantial administration overhead from the security administrator.Furthermore,the distributed nature of Web service based applications makes traditional role mining methods obsolete.In this paper,we analyze the minimal role mining problem for Web service composition,and prove that this problem is NP-complete.We propose a sub-optimal greedy algorithm based on the analysis of necessary role mapping for interoperation across multiple domains.Simulation shows the effectiveness of our algorithm,and compared to the existing methods,our algorithm has significant performance advantages.We also demonstrate the practical application of our method in a real agent based Web service system.The results show that our method could find the minimal role mapping efficiently.展开更多
Aiming at the shallow depth seam proximity beneath a room mining goaf, due to that the shallow depth seam is exploited using the longwall mining and overlain by thin bedrock and thick loose sands, many accidents are l...Aiming at the shallow depth seam proximity beneath a room mining goaf, due to that the shallow depth seam is exploited using the longwall mining and overlain by thin bedrock and thick loose sands, many accidents are likely to occur, including roof structure instability, roof step subsidence, damages of shield supports, and the face bumps triggered by the large area roof weighting, resulting in serious threats to the safety of underground miners and equipment. This paper analyses the overlying strata movement rules for the shallow seams using the physical simulation, the 3DEC numerical simulation and the field mea- surements. The results show that, in shallow seam mining, the overburden movement forms caved zone and fractured zone, the cracks develop continuously and reach the surface with the face advancing, and the development of surface cracks generally goes through four stages. With the application of loose blast- ing of residual pillars, reasonable mining height, and roof support and management, the safe, efficient and high recovery rate mining has been achieved in the shallow depth seam proximity beneath a room min ing goal.展开更多
文摘Web service composition is a low cost and efficient way to leverage the existing resource and implementation.In current Web service composition implementations,the issue of how to define the role for a new composite Web service has been little addressed.Adjusting the access control policy for a new composite Web service always causes substantial administration overhead from the security administrator.Furthermore,the distributed nature of Web service based applications makes traditional role mining methods obsolete.In this paper,we analyze the minimal role mining problem for Web service composition,and prove that this problem is NP-complete.We propose a sub-optimal greedy algorithm based on the analysis of necessary role mapping for interoperation across multiple domains.Simulation shows the effectiveness of our algorithm,and compared to the existing methods,our algorithm has significant performance advantages.We also demonstrate the practical application of our method in a real agent based Web service system.The results show that our method could find the minimal role mapping efficiently.
基金provided by the National Natural Science Foundation of China (No. 51304202)the Natural Science Foundation of Jiangsu Province of China (No. BK20130190)+1 种基金the Fundamental Research Funds for the Central Universities (No. 2013QNA28)the Priority Academic Program Development of Jiangsu Higher Education Institutions (No. SZBF2011-6-B35)
文摘Aiming at the shallow depth seam proximity beneath a room mining goaf, due to that the shallow depth seam is exploited using the longwall mining and overlain by thin bedrock and thick loose sands, many accidents are likely to occur, including roof structure instability, roof step subsidence, damages of shield supports, and the face bumps triggered by the large area roof weighting, resulting in serious threats to the safety of underground miners and equipment. This paper analyses the overlying strata movement rules for the shallow seams using the physical simulation, the 3DEC numerical simulation and the field mea- surements. The results show that, in shallow seam mining, the overburden movement forms caved zone and fractured zone, the cracks develop continuously and reach the surface with the face advancing, and the development of surface cracks generally goes through four stages. With the application of loose blast- ing of residual pillars, reasonable mining height, and roof support and management, the safe, efficient and high recovery rate mining has been achieved in the shallow depth seam proximity beneath a room min ing goal.
