Execution Of Web Services Research Articles

New Mobile Cloud Computing Approach Based Multi-Agent System For OWL-S Services

Using mobile cloud technology, local application resources can move into the cloud computing resource pool in the form of web services. The web services discovery and execution processes in the mobile environment are considered as a very difficult challenge. Moreover, these processes may degrade network performance due to the mobile environment. To overcome these issues, we present a new approach for better discovery, selection, execution, and negotiation of OWL-S services by utilizing a multi-agent system in mobile cloud computing. By using the Multi-Agent System (mobile agent and fixed agent), these processes are made with the minimum utilization of resources because the mobile agents migrate to targeted services and interact locally with them. Moreover, the use of mobile agent overcomes the problems related to the mobile environment and wireless devices. Besides, it automatizes the discovery, selection, execution, and negotiation of OWL-S services. The obtained results demonstrate the effectiveness of the proposed system. Moreover, we conclude that the mobile agent is a good solution to eliminate the problem of wireless devices and the mobile environment, and reduced the execution time of service discovery and invocation. Also, the finding indicates that cloud computing is a good solution to eliminate the problem of storage and execution in mobile devices. Besides, the context-aware provides a more accurate service selection.

A Correct-by-Construction Model for Verifying Transactional Composite Services Configuration

Reusability is a central concept of Web services as it allows for the construction of composite Web services at a lower cost/effort. Web services offer diverse functional capabilities (e.g., ticket purchase, hotel booking) and inherent transactional properties. However, due to the lack of an explicit and formal description of these functional and transactional perspectives, the correctness of the transactional reliability and functional properties cannot be verified. The composite Web service reliability is computed using a set of transactional requirements defined by designers throughout the Accepted Termination States (ATS) concept. The main objective of this article is to introduce a formal model of the Web service configuration and its correctness requirements that permit to ensure the correct Web service execution from functional and transactional points of view. For that purpose, we developed a Correct Configuration Model for Transactional Composite Services (CCM4TCS) using the <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Event-B</small> method. This model is used to formally validate the consistency of composite Web service configuration’s properties and requirements. It allows also to check the correctness of ATS constraints that we use as reliability parameters. The correctness and the validation of our model are ensured by discharging proof obligations and by animating the specification using the ProB model-checker.

Trapping Runtime Faults from Web Service Fault Ontology

The ontology offers a clear considerate of the runtime faults in web services and helps to share this common understanding with users and applications. This paper presents Web Service Fault Ontology and to trap the runtime faults from the Web Services Fault Ontology. Web Service Fault Ontology has been developed to represent the different types of faults that can occur during the interactions between service users, service publishers and service registries: publishing, discovery, binding and execution of web services. Ontology has been proposed to define the intended behavior of web services from the service provider. A sample web service application was developed for testing the proposed model.

GPU Accelerated TOPSIS Algorithm for QoS Aware Web Service Selection

Web service selection is the method of selecting the best web service based on non-functional aspects. With proliferation of web services, there is a demand for efficient approaches to select the best web services from the available pool. A number of Multi criteria decision making approaches are adopted for QoS aware web service selection. The exploitation in web service deployment increases the computation power in executing web service selection. Graphics processing unit (GPU) can achieve reduction in computation power by performing multiple tasks at a time. The independent tasks in the algorithm are parallelized by utilizing GPU in order to achieve more efficiency. This works proves that GPU acceleration can be utilized in parallelizing TOPSIS algorithm for web service selection.

A weakest link-driven global QoS adjustment approach for optimizing the execution of a composite web service

In service-oriented computing, service composition pertains to developing solutions quickly to satisfy new business requirements. Service composition provides flexible integration across distributed and heterogeneous web services to create a composite web service (CWS). However, global quality of service (QoS) of a CWS is dependent on the QoS of multiple component (or partner) web services that are integrated to form the CWS. In this context, an important research challenge is how to optimize the QoS of a CWS by detecting and adapting to runtime anomalies in component web services. A vital research issue is how to provide optimized CWS by effectively monitoring and identifying the weakest links (i.e., component web services with worst performance metrics). In this paper, a novel global QoS adjustment approach based on sensitivity analysis is proposed for detecting a component web service acting as a weakest link or a bottleneck in a CWS. This is demonstrated with an experiment, and an evaluation is performed for representing the effectiveness and performance of the proposed approach.

Interoperable and network‐aware service workflows for big data executions at internet scale

SummarySharing of computing resources and workload across different big data frameworks is challenging due to their lack of interoperable interfaces. In contrast, web services natively support an interoperable execution. Therefore, an increasing number of big data workflows are composed of data services and web service implementations that access and process big data. On the other hand, big data execution in the wide area networks needs to minimize latency and communication overheads to be able to scale seamlessly. Lack of network‐awareness of classic web service execution beyond data centers significantly challenges the scope of data services.Software‐Defined Networking (SDN) offers better control and management to the network, by unifying the control plane centrally, away from the distributed data plane devices. In this paper, we propose Software‐Defined Data Services (SDDS), an SDN‐based distributed service composition and workflow placement approach for data services in wide area networks. We first present the design of an SDDS framework that models the big data executions as composable data service workflows in multi‐domain network environments. We then evaluate the performance of a prototype SDDS framework through microbenchmarks. The benchmarks highlight the efficiency of SDDS in data service execution inside and beyond data centers.

A Novel Framework to Automatically Generate Executable Web Services From BPMN Models

Enterprise resource planning (ERP) is a business process management system in which integrated applications are used to manage business processes in a shared data environment. ERP systems usually deal with the two types of business processes, i.e., exchange and conversion. In the exchange process, economic resource, such as product, exchanges to another economic resource, such as the sales process. In a conversion process, an enterprise consumes resources in order to produce new resources, such as the distribution process. Generally, the communication between ERP applications, based on the conversion and exchange processes, is accomplished through Web services. In this context, the implementation of Web services in ERP systems is a complex task. To manage this, the business process model and notation (BPMN) are frequently utilized to simplify the development of ERP applications. However, state-of-the-art BPMN approaches usually deal with the modeling of exchange processes without considering the conversion process. Furthermore, the model transformation solution to automatically generate Web services from the BPMN models are hard to find in the literature. Therefore, in this paper, a novel framework is proposed that supports the modeling of both exchanges as well as conversion processes through BPMN. Particularly, a modeling approach is introduced to represent the ERP processes through BPMN concepts. Subsequently, the rules are developed to convert source BPMN models into target Service-oriented architecture Modeling Language (SoaML) models. Finally, transformation rules are developed to generate fully functional executable Java Web services from SoaML models. As a part of the research, a complete open-source BPMN to Web services transformation (B2W) tool is developed to automatically generate the Web services from the high-level BPMN models. The proposed framework is validated through multiple case studies. The experimental results prove that the proposed framework accurately generates Web services from the BPMN models, which eventually helps in developing the ERP systems with simplicity.

Mobile Cloud Computing with SOAP and REST Web Services

Mobile computing in conjunction with Mobile web services drives a strong approach where the limitations of mobile devices may possibly be tackled. Mobile Web Services are based on two types of technologies; SOAP and REST, which works with the existing protocols to develop Web services. Both the approaches carry their own distinct features, yet to keep the constraint features of mobile devices in mind, the better in two is considered to be the one which minimize the computation and transmission overhead while offloading. The load transferring of mobile device to remote servers for execution called computational offloading. There are numerous approaches to implement computational offloading a viable solution for eradicating the resources constraints of mobile device, yet a dynamic method of computational offloading is always required for a smooth and simple migration of complex tasks. The intention of this work is to present a distinctive approach which may not engage the mobile resources for longer time. The concept of web services utilized in our work to delegate the computational intensive tasks for remote execution. We tested both SOAP Web services approach and REST Web Services for mobile computing. Two parameters considered in our lab experiments to test; Execution Time and Energy Consumption. The results show that RESTful Web services execution is far better than executing the same application by SOAP Web services approach, in terms of execution time and energy consumption. Conducting experiments with the developed prototype matrix multiplication app, REST execution time is about 200% better than SOAP execution approach. In case of energy consumption REST execution is about 250% better than SOAP execution approach.

MORCA: ubiquitous access to life science web services

BackgroundTechnical advances in mobile devices such as smartphones and tablets have produced an extraordinary increase in their use around the world and have become part of our daily lives. The possibility of carrying these devices in a pocket, particularly mobile phones, has enabled ubiquitous access to Internet resources. Furthermore, in the life sciences world there has been a vast proliferation of data types and services that finish as Web Services. This suggests the need for research into mobile clients to deal with life sciences applications for effective usage and exploitation.ResultsAnalysing the current features in existing bioinformatics applications managing Web Services, we have devised, implemented, and deployed an easy-to-use web-based lightweight mobile client. This client is able to browse, select, compose parameters, invoke, and monitor the execution of Web Services stored in catalogues or central repositories. The client is also able to deal with huge amounts of data between external storage mounts. In addition, we also present a validation use case, which illustrates the usage of the application while executing, monitoring, and exploring the results of a registered workflow. The software its available in the Apple Store and Android Market and the source code is publicly available in Github.ConclusionsMobile devices are becoming increasingly important in the scientific world due to their strong potential impact on scientific applications.Bioinformatics should not fall behind this trend. We present an original software client that deals with the intrinsic limitations of such devices and propose different guidelines to provide location-independent access to computational resources in bioinformatics and biomedicine. Its modular design makes it easily expandable with the inclusion of new repositories, tools, types of visualization, etc.

MORCA: sailing bioinformatics world with mobile devices.

MotivationNearly 10 years have passed since the first mobile apps appeared. Given the fact that bioinformatics is a web-based world and that mobile devices are endowed with web-browsers, it seemed natural that bioinformatics would transit from personal computers to mobile devices but nothing could be further from the truth. The transition demands new paradigms, designs and novel implementations.ResultsThroughout an in-depth analysis of requirements of existing bioinformatics applications we designed and deployed an easy-to-use web-based lightweight mobile client. Such client is able to browse, select, compose automatically interface parameters, invoke services and monitor the execution of Web Services using the service's metadata stored in catalogs or repositories.Availability and implementationmORCA is available at http://bitlab-es.com/morca/app as a web-app. It is also available in the App store by Apple and Play Store by Google. The software will be available for at least 2 years.Supplementary informationSource code, final web-app, training material and documentation is available at http://bitlab-es.com/morca

Cost-Sensitive Probabilistic Contingent Planning for Web Service Composition

This article presents a cost sensitive probabilistic contingent planning approach for automated semantic web service composition, under the assumptions that the execution of each web service incurs some cost; its alternative outcomes along with their probabilities of occurring are known in advance; and actions do not involve delete effects. The implemented planner, MAPPPA2, produces a contingent plan in the form of a decision tree, by integrating multiple alternative deterministic plans computed by solving a determinized version of the original problem. Both the generation of the alternative deterministic plans, as well as the merging process attempt to maximize the expected utility of the final contingent plan. The article presents evaluation results regarding the approach, based on three web service composition domains.

Run Time Fault Detection System for Web Service Composition and Execution

Composite web services are a group of web services which together offer service functionality. Faults can occur during composition or execution of any of the services that make up the composite services. Run-time monitoring of web service execution enables real-time detection of faults concurrent with the service execution. This paper extends our previous work on fault detection of single web services to detect faults in composite web services. Fault handler has been proposed to detect faults during composition of web services for static, semi dynamic and dynamic compositions. Policies have been used to denote the intended run-time behavior of web services. Web service execution has been monitored against these policies to detect run-time faults. The proposed work has been tested using a sample web service application and the results are presented

An Adaptive Approach for Dynamic Recovery Decisions in Web Service Composition Using Space Based QOS Factor

Service Oriented Architecture facilitates automatic execution and composition of web services in distributed environment. This service composition in the heterogeneous environment may suffer from various kinds of service failures. These failures interrupt the execution of composite web services and lead towards complete system failure. The dynamic recovery decisions of the failed services are dependent on non-functional attributes of the services. In the recent years, various methodologies have been presented to provide recovery decisions based on time related QoS (Quality of Service) factors. These QoS attributes can be categorized further. Our paper categorized these attributes as space and time. In this paper, we have proposed an affinity model to quantify the location affinity for composition of web services. Furthermore, we have also suggested a replication mechanism and algorithm for taking recovery decisions based on time and space based QoS parameters and usage pattern of the services by the user.

A genetic algorithm based approach to transactional and QoS-aware service selection

As there are various risks of failure when Web services are deployed in unreliable environment, the execution of a composite Web service (CWS) requires the transaction mechanism to guarantee its reliable execution. However, the existing service selection approaches consider QoS and transaction separately and have not considered that transactional properties may affect the QoS such as the execution time of a CWS. This work addresses the importance of considering transactional properties and how the transactional properties affect the QoS simultaneously in the process of service selection by a QoS-aware and transactional-aware selection approach. First, a performance evaluation method is proposed to calculate the execution time of a transactional CWS. Then, a genetic algorithm based approach, which takes into account the execution time, price, transactional property and successful execution rate of CWS, is presented to achieve global optimisation service selection. Finally, experimental results show the efficiency and effectiveness of the approach.

Conformance Checking and QoS Selection Based on CPN for Web Service Composition

The development of new services by composition of existing ones has gained considerable momentum as a means of integrating heterogeneous applications and realizing business collaborations. More and more Web services with similar function attributes but different QoS are available. The performance of the composed service is determined by the involved Web services. Therefore, QoS properties are crucial for selecting the Web services to take part in the composition, which can identify the best candidate Web services from a set of functionally-equivalent services. Web service composition enables seamless and dynamic integration of business applications on the web. Due to the inherent autonomy and heterogeneity of component Web services, it is difficult to predict the behavior of the overall composite service. Conformance checking identifies failure and conflict of execution of composite Web service that ensures reliable execution. In this paper we use skyline computation to select services for composition efficiently, reducing the number of candidate services to be considered. Then a novel color Petri net model of Web service composition is presented that combines QoS-based optimal service selection and consistence verification. In the model we define aggregation functions, and use a Multiple Attribute Decision Making approach for the utility function to achieve optimal services selection of QoS properties. We also propose a consistence verification approach to identify potential logical inconsistence of the semantic Web service process before the deployment. Proofs are also presented. We evaluate our approach experimentally using both real and synthetically generated datasets.

Modeling dynamic recovery strategy for composite web services execution

During the execution of Composite Web Services (CWS), a component Web Service (WS) can fail and can be repaired with strategies such WS retry, substitution, compensation, roll-back, replication, or checkpointing. Each strategy behaves differently on different scenarios, impacting the CWS QoS. We propose a non intrusive dynamic fault tolerant model that analyses several levels of information: environment state, execution state, and QoS criteria, to dynamically decide the best recovery strategy when a failure occurs. We present an experimental study to evaluate the model and determine the impact on QoS parameters of different recovery strategies; and evaluate the intrusiveness of our strategy during the normal execution of CWSs.

Towards a Monitoring Framework for the Automatic Integration of the Access Control Policies for Web Services

Cloud computing is an emerging model of business computing that can be used to maintain configurable resources such as processors, networks, storage, operating systems, databases, and servers. Service oriented Architecture (SoA) is one of most successful paradigms deployed over the Cloud; is a layered architecture to organize software resources as services and to facilitate their deployment, discovery, and combination to produce new services. The coordination of innovations carried out between these services is a key challenge of SoA, as any failings in such services could result in a lack of availability, which may violate Service Level Agreements, leading to financial penalties or customer dissatisfaction. A service known as the Protocol service can be introduced and integrated within a system to coordinate innovations. This service may then be linked with a service called the Access Control Policies (AC_Policies) service, which identifies permissions of invocation of the Protocol service. Next, a real-time Business Activity Monitoring (BAM ) dashboard is automatically generated to supervise the process of assigning the Access Control Policies, along with the status of the executions of Web services. This approach is achieved by harnessing the capability of the Model-Driven Architecture (MDA) to facilitate the automatic generation of services. As a proof of concept, this approach is implemented as a plugin.

Cost‐aware execution of transactional web services using labelled transition systems

Recently web service composition has become a very cost-effective way to develop business applications. However, owing to the unreliable nature of web services, providing the transactional support in execution of a service composition is an important design requirement. To guarantee the transactional execution of service compositions, a fault-handling routine has to be started once a service failure occurs in order to undo the effect of previously completed services by calling their corresponding compensation operations. Currently this fault-handling mechanism is implemented by means of low-level programming constructs such as exception-handling mechanism in languages such as WS-BPEL. However, since the logic of handling service failures might become very complex in some applications, this concern should be separated from the normal flow of the composition workflow based on the separation of concerns principle. To achieve this, in this study we have proposed an orchestration pattern for building a transactional service composition in which the failure-recovery logic is imposed on the composition workflow by a Labelled Transition System (LTS) as a separate module. It is assumed that each service within the composition is associated with two known transactional properties: (i) a rollback cost that indicates the cost of undoing (compensating) the service and (ii) a failure probability. The transactional logic of the service composition is also specified using the rollback dependencies represented in a rollback graph. An LTS then is generated to schedule the execution of services within the composition based on the composition transactional logic and properties such that upon a service failure, a recovery path with the lowest cost is followed.

Parallel Execution of Data-intensive Web Services Based on Data-flow Constructs and I/O Operation Ratio

Parallel Execution of Data-intensive Web Services Based on Data-flow Constructs and I/O Operation Ratio

Reliable Composite Web Services Execution: Towards a Dynamic Recovery Decision

During the execution of a Composite Web Service (CWS), different faults may occur that cause WSs failures. There exist strategies that can be applied to repair these failures, such as: WS retry, WS substitution, compensation, roll-back, or replication. Each strategy has advantages and disadvantages on different execution scenarios and can produce different impact on the CWS QoS. Hence, it is important to define a dynamic fault tolerant strategy which takes into account environment and execution information to accordingly decide the appropriate recovery strategy. We present a preliminary study in order to analyze the impact on the CWS total execution time of different recovery strategies on different scenarios. The experimental results show that under different conditions, recovery strategies behave differently. This analysis represents a first step towards the definition of a model to dynamically decide which recovery strategy is the best choice by taking into account the context-information when the failure occurs.