Web Service Composition Process Research Articles

PIRAP: Security Assessment Framework for Heterogeneous Web Service Composition

In recent times, enterprise environments such as E-banking, E-commerce, etc., are greatly affected by the evolution of web services and their associated attacks. The process of web service composition gives rise to security issues due to the incompatibility standards of the Simple Object Access Protocol (SOAP) and representational state transfer (REST) features and the compromising service-level agreement (SLA) between the end parties which has not been considered yet. Also, the security assessment process needs to cooperate with good security standards and web services. In case of heterogeneous web services, assessment done using machine learning technologies makes use of pattern analysis where this does not work with the evolving trend behind the web service environment. Hence, there is a need for a security assessment model which will incorporate finite state machine (FSM) in its assessment process to keep track of the various WS-attacks that arise in the web application via web services in heterogeneous environments. The proposed model does the web service composition by compromising all the security conflicts that arise due to the usage of dissimilar web services. We experimented the concept by testing several web services and observed that the performance of the proposed framework in attack detection is accurate and automatic thereby achieving traceability and computability metrics.

Investigation on Blockchain Technology for Web Service Composition

The blockchain is an incorruptible digital ledger of economic transactions that can be programmed to record not just financial transactions but virtually everything of value. Blockchain technology makes breakthroughs in business intelligence in many areas such as banking sector, finance, judiciary, commerce, and information technology. Web service compositions have a revolutionary impact on business intelligence by enabling loose coupling, data consolidation from diverse sources, consolidation of information under a single roof, easing ad-hoc querying and reporting. The objective of current work is to investigate the applicability of blockchain for the semantic web service composition process. The paper focuses on design of conceptual architecture and the algorithm for QoS-aware semantic web service composition (SWSC) using blockchain.

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.

Web service composition on IoT reliability test based on cross entropy

AbstractWeb service has developed the managed IoT application to let connected devices easily and securely interact with cloud applications and other devices. As an important factor for web service, the reliability of web services refers to the probability of web service running success. For modeling web service composition, we should abstract the process of web service composition. Due to the diversity and complexity of web service composition, it is unlikely to do exhaustive testing. In order to improve the quality of web service composition test cases and find out which path leads to the greatest probability of service combination failure, heuristic test case generation method is adopted to obtain the optimal test path. First, the web service composition test is abstracted into the MDP model. The QoS of the web service composition is taken as the software test optimization goal, and the cross‐entropy strategy is used to optimize the test case. The experimental results show that the test profile given by the cross‐strategy is better than the random test strategy. Detect and exclude the same number of software defects. Cross‐entropy strategy can significantly reduce the number of test cases, reduce test costs, and improve defect detection efficiency.

Applying Aspect Oriented Programming in Distributed Application Engineering

Aspect-oriented programming is an emerging programming paradigm that stretches during the development phases in different domains. Many researchers have focused on the use of this paradigm in web service composition in different research axis. However, none of them use together aspect-oriented programming and design by contract to deal with the adaptation of the parameters in the web service composition process. This paper proposes a web service composition algorithm based on the planning graph using both Aspect-oriented programming and design by contract concept. The aspect-oriented Programming approach provides explicit support for separation of crosscutting concerns in web services composition whereas the design by contract approach allows the processing of parameters execution in pre-condition and post-condition mode by using contracts in order to ensure correct service execution with adaptation to external parameters without touching in properties which can be dealt with re-construction of the composite service. Future development of this planning graph will include the introduction of the dynamic way of aspect oriented programming and add comparison results.

A Framework for Trustworthy Web Service Composition and Optimization

Recently, Web service composition and optimization have received an increasing attention from both academia and industrial community. Most current methods have not paid enough attention to the user specific trust requirement for composite services. However, Trust is an important metric to judge whether a composite service can behave as user expected. In this work, firstly, a multifactor concept of trust of composite service is defined based on the trust of component services, interface compatibility and optimal binding schemes. Secondly, a trustworthy Web service composition and optimization framework called TWSCO is proposed to guarantee the trust of composite service and efficiency of Web service composition process. The interface-matching problem among component services and user preference are considered in TWSCO, which firstly uses component services filter to remove untrusted component services. Secondly, the concrete services, based on interface similarity, are organized as clusters. Thirdly, a composite template among component services is formed at the cluster level to guarantee the trust and efficiency of composite service. finally, the best binding scheme is discovered by an optimization method based on user specific trust metrics. In the end, experiments based on real Web services are presented to illustrate the proposed framework TWSCO can effectively guarantee the user preference trust of the composite service.

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.

Semantic web service composition using semantic similarity measures and formal concept analysis

One of the main assets of the Service Oriented Architecture (SOA) is composition, which consists in developing higher-level services by re-using well-known functionality provided by other services in a low-cost and rapid development process. In this paper, we present IDECSE a new integrated approach for composite services engineering. By considering semantic Web services, IDECSE addresses the challenge of fully automating the classification, discovery and composition while reducing development time and cost. The classification and the discovery processes rely on adequate semantic similarity measures. Both semantic and syntactic descriptions are integrated through specific techniques for computing similarity measures between services. Formal Concept Analysis (FCA) is used then to classify Web services into concept lattices in order to facilitate relevant services identification. A graph based semantic Web service composition process was proposed within the IDECSE framework. Using semantic similarities in grouping classes of services and in composing services shows a significant improvement compared to other approaches.

A Development of AWSCPM Framework for Automation of Web Services Composition Processes

A Development of AWSCPM Framework for Automation of Web Services Composition Processes

Development of a mobile web services discovery and composition model

Mobile computing, a challenging paradigm aiming at using and providing services anywhere and anytime, places great challenges on dynamic service discovery and composition. These challenges are specially related to mobile context (terminal constraints, user mobility, network connection, etc.) In fact, the discovery model began with semantically rewriting and enriching services and user query with OWL-S ontology and its non-functional properties (context, QoWS and user preferences). Then a similarity calculation step has been performed between the enriched user query and the set of advertised web services to generate the most relevant ones. Furthermore, the resulting services will be the inputs of a mobile web service composition process. Mobile web service composition is based on a formal model aiming to compute dynamic context (Location, Bandwidth) uncertainty and web service sensitivity. These values contribute to select web services that will form the composition plan. The web service composition algorithm suggests to the end user, the most relevant plans sorted in ascending order according to their total sensitivity value. The implementation and comprehensive simulation experiments show the efficiency of the mobile web service discovery and composition models.

Formal Specification of Adaptable Semantic Web Services Composition

This article proposes a formal specification method for Web services composition based on context-aware semantic planning graph technique. The authors first use a graph planning technique to conceive an adaptable semantic Web services composition. They use an ontology based context model for extending Web services descriptions with information about the most suitable context for its use. Then, the composition problem is transformed into a semantic context aware graph planning problem to build a set of best-composed Web services based on the user's context. Because of the error-prone nature of the Web services composition process, and with the integration of context information in this process, the complexity of Web services-based systems is increasing, hence the need for formal specification and verification approaches of such systems. The authors seek to use CCA calculus, to formalize Web services composition expressed in terms of adaptable OWL-S, and transform the description of workflow patterns into the description patterns in terms of CCA, a calculus for context-aware ambients.

One size does not fit all: logic-based clustering for on-the-fly web service composition and verification

Recently, web service composition (WSC) has been widely emerging since it is obviously hopeless to develop a specific web service which can singlehandedly fulfil completely a requirement posed by clients. Moreover, as a WSC solution often needs to satisfy various kinds of constraints, its correctness is also required to be formally verified. However, composition and verification tasks always suffer from huge computational cost when applied in practice. It prompts the consideration of clustering approaches. Unfortunately, the existing web service clustering approaches accomplish neither the soundness nor completeness of a composition solution. To overcome this problem, we propose a logic-based approach for clustering web services, where logic formulae are used for representing web services and their clusters. The clustering results are then further applied for WSC in an on-the-fly manner. Our approach achieves both soundness and completeness. In experimentation, our approach also improves the performance of WSC process significantly.

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.

A Novel Rubric and Feature-based Appraisaland Comparison Framework for the Evaluationof Semantic Web Services Composition Approaches

Background/Objectives: This article proposes a novel methodology based on rubrics and feature-based schemes for the appraisal and comparison of approaches to semantic Web services composition and discovery. Methods/Statistical analysis: In order to evaluate the Semantic Web services composition and discovery approaches we created a new framework called RFSWS. This framework is the combination of traditional feature-based evaluation schemes and newly developed analytic rubrics tables. Five recently introduced prominent Semantic Web services composition approaches were identified, explained, and then evaluated/compared using RFSWS. Findings: In this work we determined aspects of Semantic Web services composition and discovery processes that can be evaluated as performance criteria in rubric tables. This is a novel application of rubrics, which have traditionally been used for grading student performance by teachers. We created a novel framework called RFSWS consisting of rubric tables and a feature-based evaluation scheme for the evaluation and comparison of Semantic Web service discovery and composition approaches, and applied it in the evaluation of five recently introduced prominent Semantic Web services composition approaches. Considering the shortcomings of existing Semantic Web services composition approaches that were discovered through this evaluation, we proposed an idealized dynamic Semantic Web service discovery and composition method, a yardstick by which all future Semantic Web services composition approaches can be evaluated. Application/ Improvements: Our novel RFSWS framework can be applied in the comprehensive and systematic evaluation/comparison of Semantic Web services discovery and composition approaches.

Co-NP-Hardness of the Soundness Problem for Asymmetric-Choice Workflow Nets

van der Aalst et al. proved that the soundness problem is solvable in polynomial time for free-choice workflow nets (FCWF-nets). However, FCWF-nets cannot model most web services composition and interorganizational business processes because the interaction among processes does not usually satisfy the free-choice requirement. Asymmetric-choice workflow nets (ACWF-nets) as a larger class than FCWF-nets can model lots of such cases. Our previous work showed that the (weak) soundness problem is co-NP-hard for three-bounded ACWF-nets. Later, Tiplea et al. proved that for three-bounded acyclic ACWF-nets, the weak soundness problem is co-NP-complete. We sharp these results in this paper. First, we prove that for ACWF-nets, whether they are one-bounded or ${k}$ -bounded ( ${k}~\boldsymbol {>} 1$ ), the soundness problem is co-NP-hard. Second, it is proven that the soundness is equivalent to the weak soundness for any acyclic ACWF-nets, i.e., an acyclic ACWF-net is sound if and only if it is weakly sound.

Preference-Based Web Service Composition: Case-Based Planning Approach

Web service selection is an indispensable process for web service composition. However it became a difficult task as many web services are increased on the web and mostly they offer similar functionalities, which service will be the best. User preferences are the key to retain only the best services for the composition. In this paper, we have proposed a web service composition model based on user preferences. To improve the process of web service composition we propose a case-based planning approach with user preferences which uses successful experiences in past to solve similar problems. In this paper we integrate user preferences in the phase of selection, adaptation and planning. Our main contributions are a new method of case retrieval, an extended algorithm of adaptation and planning with user preferences. Results obtained offer more than a solution to the user and taking both functional and non- functional requirements. trip, preferences on particular transportation companies or hotels, and times/dates for the travel. Based on the assumption that the world is regular, so similar problems have similar solutions; As a consequence, solutions for similar problems are a useful starting point for new problem-solving. Case-based planning (CBP) is a problem-solving method that uses a library of cases, where a case associates a past problem and goal description with a plan that solves the problem by achieving the goal (5). In similar situations, CBP can take advantage of previous planning experiences by reusing stored plans. In this paper, we present a novel approach to compute the best service compositions based on user preferences and CBP. The proposed approach differs from the previous works in that user's preferences are taken into count as an additional input, so we model preferences and incorporate them into the user request. We use an algorithm to determine the relevant services that may be used to answer the composition request. We propose a new composition with user preferences if the request is not solved before and our system is learning from experiences. Our approach integrates the user preferences in the process of Case-Based Planning, the multi plan adaptation and the planning. We generate the plan for the user's new request by finding a composition plan from the library of cases. The newly generated plan together with the new request can now be stored as a case in the case base for future reuse. Many CBP retrieve and adapt a single plan (6) (7). We propose to retrieve multiple plans using an algorithm for retrieving based on two steps find and select according to the preferences. The sub-plans retrieved are merged and adapted to solve the problem.

Formal specification of flexible web service composition

Web services give a standard way for interface definition, transport mechanism, description, discovery and integration of services. Although the heterogeneity among applications is reduced, mismatches may occur at different levels structural, behavioural and non-functional during web services composition process. These mismatches require adaptation to ensure the correct working between web services. In this paper, we propose an approach for dynamic web service composition and adaptation. We specify formally the flexible web service composition FWSC using a rewriting logic-based language namely Maude. We show how to adapt the interfaces of existing web services without having to operate on the source manually. As a result, existing web services may be easily reused in a broader range of applications, and services libraries do not need to store many variants of a component that differ only in how the interfaces are used.

Case-Based Planning with User Preferences for Web Service Composition

Web services composition has emerged as a solution to answer the requester's requirements. However, the selection of an appropriate Web service has become a difficult task due to the number of Web services present on the Web and mostly they offer similar functionalities. User preferences are a key factor that can be used to rank candidate services and retain only the best ones. To improve the process of web service composition the authors propose a Case-Based Planning (CBP) approach based on preferences which uses successful experiences in past to solve similar problems at present or/and in the future. How to make a choice base on non-functional factors becomes a problem that need to be solved. This paper, argues that the selection should be considered in a global manner based on the user's preferences. The authors present a framework that deals with web service composition based on user preferences and CBP method. Results obtained offer more than a solution to the user and taking both functional and non-functional requirements.

Verifying the Concurrent Properties in BPEL Based Web Service Composition Process

The relatively new web service software paradigm involves services which are loosely coupled, highly reusable and flexible. By specifying the workflow of individual services, Web service composition enhances the ability to handle more complex business processes and provides many value-added services. In this article, we propose an extended control flow graph (XCFG) to formally model the workflow of Web service composition specified in BPEL, and corresponding techniques to verify concurrent properties, such as deadlock-free, non-conflict, and link non-redundant. XCFG can model not only the workflow of BPEL but also the synchronization control dependencies among concurrent activities. Meanwhile, each element of XCFG keeps record of related information of corresponding activity in BPEL so as to support further analysis and verification. Experimental study validates the effectiveness and efficiency of the proposed XCFG-based technique.

A Bounded Model Checking Approach for the Verification of Web Services Composition

In this paper, we propose a bounded model-checking based approach for the verification of declarative Web services composition processes using satisfiability solving (SAT). The need for the bounded model-checking approach stems from the nature of declarative processes as they are defined by only specifying the constraints that mark the boundary of the solution to the composition process. The proposed approach relies on using Event Calculus (EC) as the modeling formalism with a sound and complete EC to SAT encoding process. The use of EC as the modeling also formalism allows for a highly expressive approach for both the specification of composition model and for the specification of verification properties. Furthermore, as the conflict clauses returned by the SAT solver can be significantly large for complex processes and verification requirements, we propose a filtering criterion and defined patterns for identifying the clauses of interest for process verification.