Service Oriented Architecture(SOA)and Service Oriented Computing(SOC)are prevailing technologies for sharing and reusing resources.Service composition is an envisioned methodology used in SOA and SOC to build value-ad...Service Oriented Architecture(SOA)and Service Oriented Computing(SOC)are prevailing technologies for sharing and reusing resources.Service composition is an envisioned methodology used in SOA and SOC to build value-added services.The existed service composition models are mostly information technology expert-oriented and there is few considering the requirement from the point of view of end-users.Different with the IT experts,who can express their requirements using precise and well-formed formal language and understand the formal description of web service,the end-users are unnecessarily to be sophisticated on the complicated knowledge of computer science and are prone to consider the service composition in fuzzy and rough fashions.There's seldom work carried on considering the contradiction between the vague and uncertain requirements of end-user and the precise and deterministic process of service composition.Granular computing is a kind of promising methodology for solving the fuzzy and rough problems in artificial intelligence,interval theory,rough set theory and cluster analysis,etc.The basic idea of granular computing is problem solving with different granularities,which can be used in service composition to solve the aforementioned contradiction intuitively,that is,it can be used to create a multi-grain model for service composition and make users and service composition agent work in different information granule level separately.A multi-grain formal model for service composition is proposed in this paper.This model considers the requirement of customers in service composition in the end-user view and we give a formal specification on mapping the web service description to the generalized decision logic language(GDL)for construction of multi-grain service composition view.GDL is a formal logic language proposed in granular computing research community as an expecting specification for definition of granular models.The proposed model is expected to provide a more understandable view for an end-user than traditional service composition model and conforms to the human cognition mode.展开更多
In order to improve the design and implementation quality of web service compositions,formal methods are used to model them and certain properties are verified.WCFA （web service interface control flow automata）is us...In order to improve the design and implementation quality of web service compositions,formal methods are used to model them and certain properties are verified.WCFA （web service interface control flow automata）is used to model web services,especially the control flow and possible interactions with other web services.A web service composition consists of a set of interacting WCFA.The global behavior of web service compositions is captured by NWA（nested word automata）.A variation of the depth-first search algorithm is used to transform a set of WCFA into an NWA.State formulae and call stacks at each node of NWA are computed by a path-sensitive reachability analysis.Safety properties,call stack inspection properties and pre/post-conditions of service invocations are described by assertions.Then verification of these assertions is carried out by an automated SAT tool.展开更多
For most current Web Service access control methods, Web Service providers create a series of access control roles based on specified attributes. Only by meeting all the roles can a subject obtain the access to necess...For most current Web Service access control methods, Web Service providers create a series of access control roles based on specified attributes. Only by meeting all the roles can a subject obtain the access to necessary operations and resources. However, because of the dynamic and open traits of Web Services, it is difficult for Web Service providers to work out an access control policy with moderate intensity and to realize a satisfactory balance between protecting the security of resources and maintaining the service reachable rate. To provide a solution to the above problem, this paper proposed a trust compensation access control method based on the Attribute-Based Access Control model. Our main contributions include a formal description of the access control method, a method to calculate the attribute trust degree based on time decay, and the trust compensation value of the attribute trust degree, as well as a new Service Oriented Architecture （SOA） architecture and its procedures based on a detailed trust compensation access control method.展开更多
基金Supported by the National High-Tech Research & Development Program of China(863 Program)under Grant No.2006AA01Z101IBM SUR Project+1 种基金the Sci & Tech Research & Development Program of Shaanxi Province under Grnat No.2008KW-02the Sci & Tech Key Project of Shaanxi Province under Grant No.2006K04-G23
文摘Service Oriented Architecture(SOA)and Service Oriented Computing(SOC)are prevailing technologies for sharing and reusing resources.Service composition is an envisioned methodology used in SOA and SOC to build value-added services.The existed service composition models are mostly information technology expert-oriented and there is few considering the requirement from the point of view of end-users.Different with the IT experts,who can express their requirements using precise and well-formed formal language and understand the formal description of web service,the end-users are unnecessarily to be sophisticated on the complicated knowledge of computer science and are prone to consider the service composition in fuzzy and rough fashions.There's seldom work carried on considering the contradiction between the vague and uncertain requirements of end-user and the precise and deterministic process of service composition.Granular computing is a kind of promising methodology for solving the fuzzy and rough problems in artificial intelligence,interval theory,rough set theory and cluster analysis,etc.The basic idea of granular computing is problem solving with different granularities,which can be used in service composition to solve the aforementioned contradiction intuitively,that is,it can be used to create a multi-grain model for service composition and make users and service composition agent work in different information granule level separately.A multi-grain formal model for service composition is proposed in this paper.This model considers the requirement of customers in service composition in the end-user view and we give a formal specification on mapping the web service description to the generalized decision logic language(GDL)for construction of multi-grain service composition view.GDL is a formal logic language proposed in granular computing research community as an expecting specification for definition of granular models.The proposed model is expected to provide a more understandable view for an end-user than traditional service composition model and conforms to the human cognition mode.
基金The National Key Technology R&D Program of Chinaduring the 11th Five-Year Plan Period(No.2006BAH02A12)the National High Technology Research and Development Program of China(863 Program)(No.2006AA010101)
文摘In order to improve the design and implementation quality of web service compositions,formal methods are used to model them and certain properties are verified.WCFA （web service interface control flow automata）is used to model web services,especially the control flow and possible interactions with other web services.A web service composition consists of a set of interacting WCFA.The global behavior of web service compositions is captured by NWA（nested word automata）.A variation of the depth-first search algorithm is used to transform a set of WCFA into an NWA.State formulae and call stacks at each node of NWA are computed by a path-sensitive reachability analysis.Safety properties,call stack inspection properties and pre/post-conditions of service invocations are described by assertions.Then verification of these assertions is carried out by an automated SAT tool.
文摘For most current Web Service access control methods, Web Service providers create a series of access control roles based on specified attributes. Only by meeting all the roles can a subject obtain the access to necessary operations and resources. However, because of the dynamic and open traits of Web Services, it is difficult for Web Service providers to work out an access control policy with moderate intensity and to realize a satisfactory balance between protecting the security of resources and maintaining the service reachable rate. To provide a solution to the above problem, this paper proposed a trust compensation access control method based on the Attribute-Based Access Control model. Our main contributions include a formal description of the access control method, a method to calculate the attribute trust degree based on time decay, and the trust compensation value of the attribute trust degree, as well as a new Service Oriented Architecture （SOA） architecture and its procedures based on a detailed trust compensation access control method.
