Automatic Web Service Composition Research Articles

Efficient Composition Algorithm Strategies on Semantic Web Services Using Nature Inspired Approach

Web services are used all around the world for commercial purposes. It works majorly by Universal Resource Locators, which are stored in the repository UDDI. The different web service has to be composed for creating new business services. It is time dependent for composing more web services, which is massive. A semantically described WSDL description solves automatic composition of web services. Also with ontological models and languages, such as RDF, OWL, and SWRL, the better automatic discovery, selecting, integration, and composition of services have been done. Service requirements, such as connectivity, quality-of-service properties, correctness, and scalability, need to be satisfied. For achieving these, many evolutionary algorithms will be used for improving quality of service parameters. This paper describes many optimizations algorithms which will be used efficiently in optimizing composition techniques in semantic web.

Automatic QoS-aware web services composition based on set-cover problem

By definition, web-services composition works on developing merely optimum coordination among a number of available web-services to provide a new composed web-service intended to satisfy some users requirements for which a single web service is not (good) enough. In this article, the formulation of the automatic web-services composition is proposed as several set-cover problems and an approximation algorithm has been exploited to solve them. In proposed method, the web-service composition has been carried out within two main phases, the top-down expansion of the composition tree, and the production of composed service by bottom-up traversal of composition tree. In the first phase, the production of a composition tree (similar to the production of tree in problemsolving by searching) is proposed by starting from the output or post-conditions of the requested service towards its input or pre-conditions. Each node or state of the tree is a set of inputs and/or outputs or conditions, and services as tree edges illustrate the transition from one node to another. In the second phase, finding the path from the leaves of the produced composition tree to the root is considered equal to reaching the output of requested service, and this path specifies the involved services and the composition plan. The requested service input set determines the available leaves of the composition tree. To achieve each non-leaf node of the tree, a set-cover problem is produced and solved using a greedy approximation algorithm. If the production and solving of the set-cover problems continues hierarchically until it reaches the root node, the composition plan and cost of the required composition service will be specified. The main focus of this research is the joint sequential and parallel composition with the aim of producing near-optimal and QoS-aware composed services.

Preference-based AI Planning for Web Service Composition

A web service is a technology that allows data to be exchanged between applications using open protocols and standards. Web services generally offer basic functions that solve specific problems. The composition of services occurs when more complex problems need to be solved using successive invocations to other services. The automatic composition of web services is a current problem. Due to the continuous creation and updating of services, the manual composition of new services becomes impractical. Planning algorithms are an alternative to automate the process of web services composition. In particular, the planning algorithms with preferences allow users to guide the algorithm to find a solution in line with their requirements (e.g. prioritizing the use of services according to properties such as availability, cost, response time, etc.). This paper introduces a Planning approach with preferences to compose and run complex services from a set of web services given as input. To evaluate the approach, different preferences about the input services were used to obtain composition of services. As a result, we measured the feasibility of the proposed approach and the impact of the use of preferences on the composition result.

QoS-aware Automatic Web Service Composition with Multiple Objectives

Automatic web service composition has received a significant research attention in service-oriented computing over decades of research. With increasing number of web services, providing an end-to-end Quality of Service (QoS) guarantee in responding to user queries is becoming an important concern. Multiple QoS parameters (e.g., response time, latency, throughput, reliability, availability, success rate) are associated with a service, thereby, service composition with a large number of candidate services is a challenging multi-objective optimization problem. In this article, we study the multi-constrained multi-objective QoS-aware web service composition problem and propose three different approaches to solve the same, one optimal, based on Pareto front construction, and two others based on heuristically traversing the solution space. We compare the performance of the heuristics against the optimal and show the effectiveness of our proposals over other classical approaches for the same problem setting, with experiments on WSC-2009 and ICEBE-2005 datasets.

Automatic Web service composition driven by keyword query

Service-based systems (SBSs) reuse existing loosely coupled Web services to provide value-added composite ones, which brings about much flexibility when the business changes frequently. The advent of automatic Web service composition technology allows system designers to quickly build SBSs without having to manually create process models. Despite the large number of strategies proposed so far, most of them compose Web services through the user-provided initial inputs and expected target outputs, which is not convenient for users to express their functional requirements. To address this issue, we allow users to employ keywords to represent key tasks of the composed Web services. To automatically compose Web services based on the given keywords, we study a new problem of keyword search in the AND/OR graph constructed through semantically matching input-output interfaces of existing related Web services. Due to the complexity of the problem, we propose a heuristic search approach, called UP-DFS. To improve the performance of UP-DFS, we further design two types of pruning strategies. The empirical study shows that our approach can efficiently generate a semantic input-output-based Web service composition that contains all the key tasks in the right order required by users while minimizing the number of services in the composition.

Toward automatic web service composition based on multilevel workflow orchestration and semantic web service discovery

Revolutionary development of service oriented architecture (SOA) fosters the integration of software components from different distributed platforms and facilitates modelling of web service composition. However, the existing four-stage framework used for automatic web service composition (AWSC), which has drawbacks and incompleteness in terms of dynamic change of user goals, adopting the functional properties for describing the behaviour of candidate services and implementing unified composition framework. To overcome these drawbacks, we propose a framework for automatic and dynamic service composition that requires adding advances of semantics to web services and modifying the existing four-stage framework. We provide a multilevel workflow orchestration using an enhanced five stage composition framework for achieving the dynamic change of user requests and scalability for automatic composition. This proposed framework can able to handle both functional and non-functional requirements through transformation techniques for providing a feasible composition solution. Furthermore, it provides a solution for the problem of discovering and selecting the most suitable service candidates using semantic web service discovery (SWSD) mechanism.

Toward automatic web service composition based on multilevel workflow orchestration and semantic web service discovery

Revolutionary development of service oriented architecture (SOA) fosters the integration of software components from different distributed platforms and facilitates modelling of web service composition. However, the existing four-stage framework used for automatic web service composition (AWSC), which has drawbacks and incompleteness in terms of dynamic change of user goals, adopting the functional properties for describing the behaviour of candidate services and implementing unified composition framework. To overcome these drawbacks, we propose a framework for automatic and dynamic service composition that requires adding advances of semantics to web services and modifying the existing four-stage framework. We provide a multilevel workflow orchestration using an enhanced five stage composition framework for achieving the dynamic change of user requests and scalability for automatic composition. This proposed framework can able to handle both functional and non-functional requirements through transformation techniques for providing a feasible composition solution. Furthermore, it provides a solution for the problem of discovering and selecting the most suitable service candidates using semantic web service discovery (SWSD) mechanism.

Q-Graphplan: QoS-Aware Automatic Service Composition With the Extended Planning Graph

With the progress of web technologies, web services with abundant functionalities, such as video transmission, location, navigation, etc., are becoming more and more pervasive. Automatic web service composition aims to automatically combine selected elementary web services from a finite service set by matching the input and output parameters given an initial state and a goal state. Considering the end-to-end Quality-of-Service(QoS) of each web service, the service composition problem becomes an optimization problem to find the optimal solution. This paper maps this problem to an automatic planning problem and proposes Q-Graphplan based on the classical graphplan, an efficient planner for solving classical planning problems. First, we construct a planning graph based on the dependency relationships of the web services and extract essential heuristics according to the reachability analysis. Second, we convert this planning graph to a directed path generation graph. Finally, we extract the optimal solution from the path generation graph using a backward A* algorithm with the heuristics of the planning graph. Furthermore, our approach avoids redundancies when constructing the planning graph and improves the searching effectiveness in extracting solution. We conduct experiments on the WSC-2009 dataset to compare performance against present approaches, and the results show the efficiency and effectiveness of our proposed approach.

Automation of Web Services Composition Development Cycle

Since the emergence of Service Oriented Architecture and its implementation with the Web services technology, combining several Web services to response to a complex request presented a hard challenge. This is an area that has attracted the interest of many research organizations and manufactories. This paper firstly presents a summary of developed approach of Web services composition based on Model Driven Approach, and using different languages and systems, like Multi-Agent Reactive Decisional system for modeling task, Lotos language for formal verification, and Business Process Execution language for implementation. Secondly, the paper seeks to automate the generation of different processes (business process, executable process and formal process) by using the framework AWSCPM «Automatic Web Services Composition Processes based on MARDS», which is developed as part of this research work.

A Web Service Composition Approach Based on Planning Graph and Propositional Logic

To improve the computational efficiency of web service automatic composition, this article proposes a novel approach based on a planning graph and propositional logic. This approach has a forward searching stage and a backward combination stage: the former stage searches services in a service storage and performs the composition in a hierarchical architecture based on a planning graph, while the latter stage combines them via propositional logic operations. This method can obtain all composite services that contain no redundant services, and the computational complexity can be significantly reduced. Experiments are done to illustrate the effectiveness of the approach.

Multi-Agent Planning for Automatic Geospatial Web Service Composition in Geoportals

Automatic composition of geospatial web services increases the possibility of taking full advantage of spatial data and processing capabilities that have been published over the internet. In this paper, a multi-agent artificial intelligence (AI) planning solution was proposed, which works within the geoportal architecture and enables the geoportal to compose semantically annotated Open Geospatial Consortium (OGC) Web Services based on users’ requirements. In this solution, the registered Catalogue Service for Web (CSW) services in the geoportal along with a composition coordinator component interact together to synthesize Open Geospatial Consortium Web Services (OWSs) and generate the composition workflow. A prototype geoportal was developed, a case study of evacuation sheltering was implemented to illustrate the functionality of the algorithm, and a simulation environment, including one hundred simulated OWSs and five CSW services, was used to test the performance of the solution in a more complex circumstance. The prototype geoportal was able to generate the composite web service, based on the requested goals of the user. Additionally, in the simulation environment, while the execution time of the composition with two CSW service nodes was 20 s, the addition of new CSW nodes reduced the composition time exponentially, so that with five CSW nodes the execution time reduced to 0.3 s. Results showed that due to the utilization of the computational power of CSW services, the solution was fast, horizontally scalable, and less vulnerable to the exponential growth in the search space of the AI planning problem.

Constraint verification failure recovery in web service composition

Automated service composition aims at fulfilling complex tasks by combining different existing elementary web services in a workflow and creating value-added services. Many approaches have been proposed for automatic web service composition. Most of these approaches are based on the matching of input/output parameters across different elementary services. However, in addition to input/output parameters, many real-world services have applicable conditions and usage restrictions (i.e., service constraints) that are imposed by their providers. The constraints of a service should be verified prior to service call to ensure its correct execution. However, constraint verification of a composite service is different, as verification of some of the elementary services’ constraints might require execution of other elementary services inside the composite plan. In addition, failure during verification of constraints inside a composite plan results in the failure of execution of the whole composite service, which requires failure recovery for the composite service to continue execution. Composite service failure recovery implies the rollback of certain service transactions during the recovery of the composite plan. Current composite service failure recovery approaches are not adapted to the minimization of service rollbacks due to constraint verification failures. In this paper, a constraint-aware failure recovery approach is proposed to predict failures inside a composite service. Then, a method is proposed to do failure recovery based on those predictions and minimize the number of service rollbacks upon failure resulting from constraint verification. The proposed solution includes a planning-based algorithm and a novel constraint-processing method for service failure prediction and recovery. A publicly available test set generator is used to evaluate and analyze the proposed solution.

A unified algorithm to automatic semantic composition using multilevel workflow orchestration

As a result of state-of-the-art development in service oriented architecture, we need a composition framework and comprehensive algorithm to discover and compose the web services from different environments. In this paper, we present a unified semantic-oriented framework with corresponding algorithm for automatic web service composition that integrates the comprehensive process of modified multistage composition and rigor of web semantics. Our proposed unified algorithm introduces the novel features through modified five stage composition such as transformation of non-functional properties of user requirements to all stages, optimization and semantic validation of abstract workflows using workflow automata, annotating WSDL files with additional ontologies using ontology based service repository, adopting dynamic change of user requirements for discovering candidate services, and selecting most optimal services for concrete composition using non-functional properties are effectively represented. Feasible composition solution obtained for user complex requirements through semantic web service discovery mechanism for discovering and selecting the most suitable service candidates. Furthermore, our unified algorithm can provide a composition solution through wider acceptance of semantics-oriented documents such as web ontology language for services and web service modeling ontology. We evaluate the proposed unified algorithm for automatic generation of composition using our motivating scenario, namely, home loan approval inference process. We also evaluate algorithm for automated and dynamic composition on service repositories of various sizes in increasing the levels of nesting and present the performance results.

Web Service Interaction Modeling and Verification Using Recursive Composition Algebra

The design principle of composability among Web services is one of the most crucial reasons for the success and popularity of Web services. However, achieving error-free automatic Web service composition is still a challenge. In this paper, we propose a recursive composition based modeling and verification technique for Web service interaction. The application of recursive composition over a Web service with respect to a given set of Web services yields a recursive composition interaction graph (RCIG). In order to capture the requirement specifications of a Web service interaction scenario, we propose recursive composition specification language (RCSL) as a requirement specification language. Further, we employ the proposed RCIG as an interpretation model to interpret the semantics of a RCSL formula. Our verification technique is based on the generation and analysis of all possible interaction patterns. Performance evaluation results, provided in this paper, show that our proposition is implementable for the real world applications. The key advantages of the proposed approach are: (i) it does not require explicit system modeling as in model checking based approaches, (ii) it captures primitive characteristics of Web service interaction patterns, such as recursive composition, sequential and parallel flow, etc, and (iii) it supports automatic composition of services.

Supervisor Aware Service Composition Framework: An Implementation and Evaluation

In our previous work (Atampore et al., 2016b), we developed a novel supervisory control framework for automated composition of Web services. In the proposed framework, we modeled services that exchange messages and exhibit nondeterministic (runtime-dependent) behaviours based on runtime input. The objective is to synthesize a supervisor that interacts with a given set of Web services through messages to guarantee that a given specification is satisfied. The framework employs Labelled Transition Systems (LTSs) equipped with guards and data variables to model Web services and provides a technique to synthesize a controller. We modeled the interactions of services asynchronously and we used the guards and data variables to express certain preconditions which are then propagated from the system requirements through the overall composite service. In this paper, first, we present a prototype implementation of our automated web service composition framework proposed in our previous paper into a tool support: The implementation involves the following: (i) the translation of industrial Web service standard such as WS-BPEL in a formal language suitable for control synthesis; (ii) the implementation of all the proposed control synthesis algorithms in our previous work; (iii) the incorporation of runtime information into the supervisory control synthesis; and (iv) the translation of the formal language used in the synthesis back to its WS-BPEL equivalent. Second, we present the application and a preliminary evaluation of the proposed composition approach in terms of (i) its effectiveness for the generation of controllers for a composition problem and (ii) its applicability using two well-known small case studies.

CASAS: A tool for composing automatically and semantically astrophysical services

Multiple astronomical datasets are available through internet and the astrophysical Distributed Computing Infrastructure (DCI) called Virtual Observatory (VO). Some scientific workflow technologies exist for retrieving and combining data from those sources. However selection of relevant services, automation of the workflows composition and the lack of user-friendly platforms remain a concern. This paper presents CASAS, a tool for semantic web services composition in astrophysics. This tool proposes automatic composition of astrophysical web services and brings a semantics-based, automatic composition of workflows. It widens the services choice and eases the use of heterogeneous services. Semantic web services composition relies on ontologies for elaborating the services composition; this work is based on Astrophysical Services ONtology (ASON). ASON had its structure mostly inherited from the VO services capacities. Nevertheless, our approach is not limited to the VO and brings VO plus non-VO services together without the need for premade recipes. CASAS is available for use through a simple web interface.

Evolutionary computation for automatic Web service composition: an indirect representation approach

Web services have become increasingly popular in recent years, and they are especially suitable to the process of Web service composition, which is when several services are combined to create an application that accomplishes a more complex task. In recent years, significant research efforts have been made on developing approaches for performing Quality of Service -aware Web service composition. Evolutionary computing (EC) techniques have been widely used for solving this problem, since they allow for the quality of compositions to be optimised, meanwhile also ensuring that the solutions produced have the required functionality. Existing EC-based composition approaches perform constrained optimisation to produce solutions that meet those requirements, however these constraints may hinder the effectiveness of the search. To address this issue, a novel framework based on an indirect representation is proposed in this work. The core idea is to first generate candidate service compositions encoded as sequences of services. Then, a decoding scheme is developed to transform any sequence of services into a corresponding feasible service composition. Given a service sequence, the decoding scheme builds the workflow from scratch by iteratively adding the services to proper positions of the workflow in the order of the sequence. This is beneficial because it allows the optimisation to be carried out in an unconstrained way, later enforcing functionality constraints during the decoding process. A number of encoding methods and corresponding search operators, including the PSO, GA, and GP-based methods, are proposed and tested, with results showing that the quality of the solutions produced by the proposed indirect approach is higher than that of a baseline direct representation-based approach for twelve out of the thirteen datasets considered. In particular, the method using the variable-length sequence representation has the most efficient execution time, while the fixed-length sequence produces the highest quality solutions.

Automated Web Service Composition Algorithm Based on Improved Planning Graph

Automated Web Service Composition Algorithm Based on Improved Planning Graph

SemanticSCo: A platform to support the semantic composition of services for gene expression analysis

Gene expression studies often require the combined use of a number of analysis tools. However, manual integration of analysis tools can be cumbersome and error prone. To support a higher level of automation in the integration process, efforts have been made in the biomedical domain towards the development of semantic web services and supporting composition environments. Yet, most environments consider only the execution of simple service behaviours and requires users to focus on technical details of the composition process.We propose a novel approach to the semantic composition of gene expression analysis services that addresses the shortcomings of the existing solutions. Our approach includes an architecture designed to support the service composition process for gene expression analysis, and a flexible strategy for the (semi) automatic composition of semantic web services. Finally, we implement a supporting platform called SemanticSCo to realize the proposed composition approach and demonstrate its functionality by successfully reproducing a microarray study documented in the literature.The SemanticSCo platform provides support for the composition of RESTful web services semantically annotated using SAWSDL. Our platform also supports the definition of constraints/conditions regarding the order in which service operations should be invoked, thus enabling the definition of complex service behaviours. Our proposed solution for semantic web service composition takes into account the requirements of different stakeholders and addresses all phases of the service composition process. It also provides support for the definition of analysis workflows at a high-level of abstraction, thus enabling users to focus on biological research issues rather than on the technical details of the composition process. The SemanticSCo source code is available at https://github.com/usplssb/SemanticSCo.

Graph-Based Semantic Web Service Composition for Healthcare Data Integration.

Within the numerous and heterogeneous web services offered through different sources, automatic web services composition is the most convenient method for building complex business processes that permit invocation of multiple existing atomic services. The current solutions in functional web services composition lack autonomous queries of semantic matches within the parameters of web services, which are necessary in the composition of large-scale related services. In this paper, we propose a graph-based Semantic Web Services composition system consisting of two subsystems: management time and run time. The management-time subsystem is responsible for dependency graph preparation in which a dependency graph of related services is generated automatically according to the proposed semantic matchmaking rules. The run-time subsystem is responsible for discovering the potential web services and nonredundant web services composition of a user's query using a graph-based searching algorithm. The proposed approach was applied to healthcare data integration in different health organizations and was evaluated according to two aspects: execution time measurement and correctness measurement.