Service composition for ltl task specifications

Cyber-Physical Systems (CPSs) seamlessly integrate lots of heterogeneous cyber and physical entities to realize precise controlling of the physical world. Traditional service-oriented models are insufficient to effectively compose the atomic services provided by cyber and physical entities to implement a specific task. In this paper, we presented an efficient context-sensitive service composition framework for precise controlling in CPSs. We firstly proposed an ontology model for context-sensitive specification of the service abilities of physical entities. And then, the business workflow logic model was given for functionality decomposition of a task. Furthermore, the key sub-modules in service composition including the atomic service clustering scheme and QoS-aware service selection algorithm were initially investigated. Our proposed service composition framework is helpful to automate the composition process under real-time constraints and under various physical resource constraints. This preliminary solution for service composition in CPS is important and helpful for in-depth study and practical applications of CPSs.

Mobile phones are becoming an essential tool in our life. They not only act as phones and media players, but more fundamentally they give us access to variety of services that we use in everyday life, including social networking, personal assistance, entertainment, travelling, and so on. Unfortunately, while the number of services increases, each service is narrowly directed to solve a specific user task with no attention to how the user may utilize these services in combination. At this stage, the combination of services and the integration of their information flows must be managed by the user on his own, in a handcrafted way. To support the user in the composition of services and applications, we propose to organize the services around a small set of resources - time, location, social relations, money - which model the essential user assets handled by mobile services, and which guide the data integration and service composition. In the paper, we discuss our current realization of such resource-based, user-centric service composition approach, detailing the underlying conceptual architecture and discussing the actual execution of the platform on a set of practical scenarios.

Service composition is an efficient way to fulfill user requirements in service-oriented architecture by combining several web services to perform a specific task. As a result of the dynamic environment of web services, the emergence of many unexpected events can disrupt or affect the quality of services composing a web service and, hence violate the end-to-end constraints. Dynamically reconfiguring the composite web service is essential to dealing with such issues. However, recent reconfiguration methods failed to meet the end-to-end constraints due to the vast number of web services with the same functionality and different nonfunctional features (QoS). This paper proposes a Swarm Reinforcement Learning approach to replace multiple failed services and maintain the original end-to-end constraints. ACO (Ant Colony Optimization) is used to improve the exchange of information between agents based on the Pheromone-Q values, inspired by real ants’ behavior. Experiments are conducted on real data sets and compared with related work methods to prove the efficiency of the proposed approach in terms of constraint satisfaction.

Web services is a special case of a service-oriented architecture (SOA), which is, basically, a representation of web application‘s functionality. Web service is more of a generalized concept that implies whole functionality as a whole but Microservice handles only the single specific task. MSA is emerging as an excellent architecture style enabling the division of large and complex applications into micro-scale yet many services, each runs in its own process, has its own APIs, and communicates with one another using lightweight mechanisms such as HTTP. Microservices are built around business capabilities, loosely coupled and highly cohesive, horizontally scalable, independently deployable, technology-agnostic, etc. On the other side for the business dynamic requirement these microservices need to be composed for the realization of enterprise-scale, and business-critical applications. Service composition is combining various services together to provide the solution for the user dynamic queries. There are two methods for the microservice composition i.e. orchestration and choreography. In this paper,a health case study is performed for the selection mechanism of orchestration method and choreography method in various situation.