Dynamic Service Composition

Abstract

Abstract-Service is a network addressable software component to perform a specific task. A service discovery mechanism can be used to find services that can be executed to satisfy a service request. A service composition generates a composition plan and a composite service to satisfy a service request. Static composition process consumes considerable amount of time and effort. It is also vulnerable to changes in input/output of services. A dynamic composition algorithm can automatically select services involved in composite plan and generate a composite service on-the-fly. Composition time taken by the algorithm to generate a composite service is the main issue with dynamic composition algorithms. Dynamic composition algorithms presented in previous work mainly follow either forward chaining approach (FCA) or backward chaining approach (BCA) to generate a composite service. Their performance suffers for certain cases to generate a composite service where the number of services explored increases exponentially as number of iterations increases. This work proposes a dynamic composition algorithm that gives consistent performance across all the cases. Proposed algorithm approaches from two directions alternatively, one follows FCA and another follows BCA. Proposed algorithm explores less number of services and takes less composition time compared to algorithms FCA or BCA.

Goal-Driven Service Composition in Mobile and Pervasive Computing

“…Khakhkhar et.al. [5] proposed a bidirectional planning algorithm that combines a forwardchaining approach and a backward-chaining approach. It allows systems to plan a composite service from the input data and the goal output at the same time.…”

“…Open issues with current research on service composi-tion (e.g., goal-oriented planning [5], open workflows [6] [7] [8], adaptable composition [9] [10] [11] and AI planning [12] [13] ) are that i) existing service composition models are inflexible; and ii) the composition models have limited support for handling composite service adaptation. Specifically, workflow-driven solutions [6] [7] [8] model user requirements as a complex task request in the form of workflows (i.e., abstract composite services).…”

Cognitively-Inspired Agent-Based Service Composition for Mobile and Pervasive Computing

“…Such a workflow may need to be generated offline by a domain expert or a composition planning engine, which is inconvenient when a change is required at runtime. Dynamic service planning approaches such as [12,17]use classic AI-planning algorithms, such as forward-chaining and backward-chaining for dynamic composition planning, and usually employ a bi-direction planning algorithm to find a path with the smallest cost from the dependency graph. However, these approaches require central service repositories to maintain service overlays, and have no support for dynamic composition replanning for composition failures.…”

A Semantic-Aware Approach for Automatic Cloud Services Composition

“…The proposed algorithm adopts Forward-Chaining and Depth-First methods [18] to generate composite services. The algorithm takes the input of the request as the start point, and the output of the request as the end point, and then finds all composite services may generate between these points.…”

“…A composite service [18] is a set of linked services, in a Semantic Network, that forms a path, which begins with the requested input and ends with the requested output.…”