Context-aware Web Services Research Articles

Dependency Network-based Trust Management for Context-Aware Web Services

A major challenge for Web services trust management is the continuous changing running environments. In such context environments, Web services have difficulty guaranteeing the quality of service. In this paper, we propose a trust management model for context-aware Web services based on the Dependency Network. The novelty of our trust model lies in leveraging the cyclic dependency relations among the quality of service metrics and context environments. Experiments conducted on a real-life dataset demonstrate the capability of our trust model compared to Bayesian Network-based trust model.

An evolutionary clustering approach based on temporal aspects for context-aware service recommendation

Over the last years, recommendation techniques have emerged to cope with the challenging task of optimal service selection, and to help consumers satisfy their needs and preferences. However, most existing models on service recommendation only consider the traditional user-service relation, while in the real world, the perception and popularity of Web services may depend on several conditions including temporal, spatial and social constraints. Such additional factors in recommender systems influence users’ preferences to a large extent. In this paper, we propose a context-aware Web service recommendation approach with a specific focus on time dimension. First, K-means clustering method is hybridized with a multi-population variant of the well-known Particle Swarm Optimization (PSO) in order to exclude the less similar users which share few common Web services with the active user in specific contexts. Slope One method is, then, applied to predict the missing ratings in the current context of user. Finally, a recommendation algorithm is proposed in order to return the top-rated services. Experimental studies confirmed the accuracy of our recommendation approach when compared to three existing solutions.

Context-Aware Web Service Composition based on AI Planning

ABSTRACTA web service is an application that is published on the web and can be discovered and used automatically. In many cases, a web service cannot provide the capability that the user has requested. Therefore, according to the user request, it should be possible to combine various services and produce a new composite service for the user request. Context is the information that can be used to characterize the situation of an entity. In this paper, we present our context model for web service composition and implement the newly proposed framework for context-aware web service composition and show how the newly proposed framework reduces the number of failures and composition time.

Graph Planning Based Composition For Adaptable Semantic Web Services

This paper proposes a context-aware semantic planning graph technique for Web services composition. We first use an ontology based context model for extending Web services descriptions with information about the most suitable context for its use. Then, we transform the composition problem into a semantic context aware graph planning problem to build a set of best composed Web services based on user’s context. The construction of the planning graph is based on semantic context-aware Web service discovery. This allow, for each step of the construction, to add most suitable Web services in terms of semantic compatibility between the services parameters, and their context similarity with the user’s context. In the backward search step, semantic and contextual similarity scores are used to find composed Web services list. Finally, in the ranking step, a score is calculated for each candidate solution and a set of ranked solutions is returned to the user.

An Enhanced Multi-Layered Security Framework for Context-Aware Mobile Web Services

People seeking medical attention go in search of medical centers and specialists. For them time is vital as they search for resources, the information should be available with minimum latency. With the advent of wearable computing and ubiquitous computing Context -Aware Web services can be available with much ease, it enables users to retrieve information with relation to their context. While providing several benefits, although web services technology has been facing serious threats like prefix hijacking and interception in the Internet due to a man in-the-middle attack which compromises privacy of the user. The objective of this research work is to provide a secure framework for Context aware web services using access control mechanisms. It was found web services are prone to data theft and malicious attacks, Access Control Mechanism is introduced in the framework to provide a secured architecture where the privacy of the person accessing the web service will be preserved. The proposed architecture provides an end-to-end security by accomplishing the security properties such as user authentication, authorization of web services, message confidentiality, data integrity and non repudiation. Hence, there is a need that arises to design a security system for context-aware web services with the support of end-to-end security in business services between the service providers and service requesters thus providing a secure user experience

SEMANTIC SIMILARITY BASED CONTEXT-AWARE WEB SERVICE DISCOVERY USING NLP TECHNIQUES

Due to the high availability and also the distributed nature of published web services on the Web, efficient discovery and retrieval of relevant services that meet user requirements can be a challenging task. In this paper, we present a semantics based web service retrieval framework that uses natural language processing techniques to extract a service’s functional information. The extracted information is used to compute the similarity between any given service pair, for generating additional metadata for each service and for classifying the services based on their functional similarity. The framework also adds natural language querying capabilities for supporting exact and approximate matching of relevant services to a given user query. We present experimental results that show that the semantic analysis & automatic tagging effectively captured the inherent functional details of a service and also the similarity between different services. Also, a significant improvement in precision and recall was observed during Web service retrieval when compared to simple keyword matching search, using the natural language querying interface provided by the proposed framework.

Context Aware QOS based Web Service Discovery

This work concentrates on context of the execution environment in service selection process due to dynamically varying QoS attributes in service execution environment. In this paper, a context aware QoS Web Service(WS) description and discovery is proposed to overcome the issues related to QoS requirements in WS. In the proposed scheme, OWL-Q with OWL CONtext ONtology (CONON) ontology is modeled to provide the WS description with context aware QoS descriptions. To discover the most appropriate WS based on context and QoS descriptions, a context aware QoS semantic matchmaking algorithm is newly proposed based on Constraint Satisfaction Optimization Approach (CSOP). An efficient User Priority based Ranking (UPR) mechanism is performed based on user preferences to rank the matched WSs. Consequently, precision and recall of proposed context aware QoS WS discovery is compared with the existing QoS WS discovery and conclude that proposed approach achieves high precision and recall than existing QoS based approach.

Hybrid service matchmaking in ambient assisted living environments based on context-aware service modeling

Ambient assisted living (AAL) environments are augmented with sensing and communication technologies to support elderly people with personalized, adaptive and anticipatory requirements. A plethora of heterogeneous devices and services appear and disappear, which expose different behavior with the changing contexts in these environments. Therefore, a service matchmaking mechanism that attempts to identify relevant services in order to fulfill the user needs, has to deal with the heterogeneity of devices and services along with their dynamic behavior. Existing service specifications, such as semantic web services, are often used to abstract the environment's functionalities and the user tasks without incorporating context-aware properties, which makes them unsuitable for service matchmaking in pervasive and ambient environment. To deal with these issues, we introduce a contExt Aware web Service dEscription Language (wEASEL) that is an abstract service model to represent services and user tasks in AAL environments. Also, we present a set of wEASEL-based service matching algorithms and evaluate them for their suitability. The proposed service matchmaking mechanism can incorporate services that are available in local AAL environment as well as in the cloud computing marketplace.

A framework for context-aware web service composition using planning techniques

A web service is an application that is published on the web and can be discovered and used automatically. In many cases, a web service cannot provide the capability that the user has requested. Therefore, according to the user request, it should be possible to combine various services and produce a new composite service for user request. AI planning techniques are used for automated web service composition. Also, context is the information that can be used to characterize the situation of an entity. JSHOP2 is one of the techniques of planning. In this paper, the design and implementation of the proposed framework for context-aware web service composition is presented and is used JSHOP2 and the proposed framework reduces the number of failures and composition time.

A User-Aware Approach to Provide Adaptive Web Services

Web services are rapidly gaining acceptance as a fundamental technology in the web fields. They are becoming the cutting edge of communication between the different applications all over the web. Because of today's wide diversity of devices to- gether with the variety of the user's preferences, context-aware web services are becom- ing a fundamental challenge that must be targeted. This issue is a part of the Human Computer Interaction (HCI) discipline and it aims at adapting the web service behavior according to the user's context such as his specific work environment, language, type of Internet connection, devices and preferences. Many solutions have been proposed in this area. Nevertheless, the adaptation was carried out only at the runtime and it partially covered the user's general context. In this paper, we introduce a new context-aware approach that provides adaptive web services. Our approach allows to express require- ments by taking into account potential user's profile in addition to the functional one. While the latter ensures the description of the web service-functionalities, adaptation expresses the ability of a service to be self-adapted to runtime context changes. Our approach deals with adaptation from the very beginning of the modeling step of a web service. Furthermore, it upgrades description and publication usual methods in order to support profile specification.

A Novel Process Network Model for Interacting Context-Aware Web Services

Context-aware web services have been attracting significant attention as an important approach for improving the usability of web services. In this paper, we explore a novel approach to model dynamic behaviors of interacting context-aware web services, aiming to effectively process and take advantage of contexts and realize behavior adaptation of web services and further to facilitate the development of context-aware application of web services. We present an interaction model of context-aware web services based on context-aware process network (CAPN), which is a data-flow and channel-based model of cooperative computation. The CAPN is extended to context-aware web service network by introducing a kind of sensor processes, which is used to catch contextual data from external environment. Through modeling the register link's behaviors, we present how a web service can respond to its context changes dynamically. The formal behavior semantics of our model is described by calculus of communicating systems process algebra. The behavior adaptation and context awareness in our model are discussed. An eXtensible Markup Language-formatted service behavior description language named BML4WS is designed to describe behaviors and behavior adaptation of interacting context-aware web services. Finally, an application case is demonstrated to illustrate the proposed model how to adapt context changes and describe service behaviors and their changes.

Towards Context Aware QOS-Based Web Service Description and Discovery

This work concentrates on context of the execution environment in service selection process due to dynamically varying QoS attributes in service execution environment. In this paper, a context aware QoS Web Service (WS) description and discovery is proposed to overcome the issues related to QoS requirements in WS. In the proposed scheme, OWL-Q with OWL CONtext ONtology (CONON) ontology is modelled to provide the WS description with context aware QoS descriptions. To discover the most appropriate WS based on context and QoS descriptions, a context aware QoS semantic matchmaking algorithm is newly proposed based on Constraint Satisfaction Optimization Approach (CSOP). An efficient User Priority based Ranking (UPR) mechanism is performed based on user preferences to rank the matched WSs. Consequently, precision and recall of proposed context aware QoS WS discovery is compared with the existing QoS WS discovery and conclude that proposed approach achieves high precision and recall than existing QoS based approach.

Consumer Privacy Enforcement in Context-Aware Web Services

Privacy protection constitutes a genuine human right reflected both in the legislation and in different aspects of software engineering. Sensitive information needs to be protected in end-users interaction with Web Services especially in cases, where context-aware features are included. In this work the authors address the inclusion of consumer privacy preferences in the provision of context-aware Web Services. To achieve this the authors propose, on the one hand, a preferences language, where end-users can specify their privacy options, namely Consumer Privacy Language, and, on the other hand, a seamless enforcement mechanism that considers consumer preferences by intercepting and modifying appropriately Simple Object Access Protocol request and response messages. The enforcement approach has been evaluated based on various execution metrics for an example use case consisting of various Web Services and for different users configurations demonstrating the usefulness of the approach assisting towards the provision of privacy-aware environments.

Context-aware web services for security control and privacy preservation in an RFID supply chain

Automation and optimisation of supply-chain activities are made possible by radio frequency identification RFID technology. RFID supply chain performance can be enhanced by integrating RFID functions into the web service paradigm. However, the use of RFID involves growing privacy and security concerns, in part because the lack of RFID tag capacity places the whole supply-chain loop at risk of security such as product counterfeiting. In this paper, we tackle the security and privacy challenges in RFID by using context-aware web service technology. By employing a seven-layer trust framework, we design the functionalities to comply with web service architecture. In order to address the security and privacy problems, we also use the context parameters such as location and time to model the situations of RFID tags. A complete case of RFID-enabled supply chain in an EPCglobal network using context-aware web services is provided to tackle the RFID security and privacy challenges.

A synergy between context-aware policies and AOP to achieve highly adaptable Web services

Modern service-based systems are frequently required to be highly adaptable in order to cope with rapid changes and evolution of business goals, requirements, as well as physical context in a dynamic business environment. Unfortunately, adaptive systems are still difficult to build due to their high complexity. In this paper, we propose a new approach for developing highly adaptable Web services based on a synergy between context-aware Web service policies and Aspect-Oriented Programming. This synergy is achieved through the elaboration of an innovative extension of the Web Service Policy Language (WSPL), which allows for context specification at both policy and rule levels. In addition, we provide a tool for the development of aspect-oriented policies, including an option to translate WSPL policies into aspect-oriented policies. These policies can be automatically woven into composite Web services (e.g., a BPEL process). The elaborated synergy between context, policies, and aspects allows service providers to increase the level of adaptability of Web services at different layers of applications.

Behaviour adaptation of context-aware web services in pervasive computing environment

Pervasive computing is regarded as the next generation of computing environment in which users can access resources and obtain services anywhere and anytime. In this paper, we use context-aware web services to realise the 'everywhere' feature of pervasive computing environment. We explore a novel behaviour adaptation mechanism for context-aware web service, aim to effectively process and take advantage of contexts and realise behaviour adaptation of web services in pervasive computing environment. We use register link to store context information which comes from external environment. Through modelling the register link's behaviours, we present how a web service can respond to its context changes dynamically. We also introduce constraint-based behaviour version selection mechanism and design a behaviour adaptation framework for context-aware web service. Finally, we present an application case to show how to describe service behaviours and how the application can adapt to context changes.

Context-aware services engineering

Context-aware Web services are identified as an important technology to support new applications on the future Internet. Context information has several qualities that make the development of these services challenging, compared to conventional, Web services. Therefore, sound software engineering practices are needed during their development and execution. This article discusses a novel software engineering-based approach, which leverages the benefits of model-driven architecture, aspect-oriented modeling, and formal model checking, for modeling and verifying context-aware services. The approach is explored using a real-world case study in intelligent transport. An evaluation framework is established to validate the main methods and tools employed.

A Novel Approach for Web Service Run Time Exception Handling

Service Computing has recently gained significant momentum to enable the IT services and computing technology to perform business services more efficiently and effectively. Runtime management has been given utmost significance as a potential strategy to handle runtime exceptions increases the adaptability of services to exceptional circumstances. service computing aims for efficiently handling run time issues during service computation such as exception handling, change management and dynamic reconfigurable services. There are many exceptions often raised during service consumption and execution at run time and some of them gets resolved, but many of them failed to resolve due to the lack of run time exception handling mechanism. In this paper we propose a model for context aware web service exception handling targeting service life time and service reaction time which could determine whether the exception is solvable or un solvable with respect to the exception context with time and policy constraints. Thus a novel approach for web service runtime exception handling has been proposed which affords facilities for managing the runtime exception with the help of a set of QoS parameters that are satisfying the service computational criteria such as computability, traceability, and decidability. In addition to that, it supports serviceability, manageability, availability and configurability. The results encourage new direction of research with performance upgrade in the field of service computing for runtime exception handling.

Development of context-aware web services using the MDA approach

Nowadays, software engineering is moving towards the development of ubiquitous and distributed applications. This tendency is constrained by parameters such as mobility and heterogeneity that characterise the current situation of a user. In this work, we aim to integrate the separation between aspects for the context aware services development process by using the MDA taking maximum advantages of this approach. We aim to automating the development process by using tools, which ensures better productivity, improve product quality and facilitates the maintenance. A meta model allowing modelling any contextual information and taking into account the separation of aspects and the context in the early stages of development is proposed. Web services adaptation to different contextual situations by automating the development lifecycle of services and exploiting all the performance conditions is our concern and the transformation step is investigated and a transformer is developed. This provides greater relevancy, improves user interaction and greatly facilitates application development, maintenance and integration of context aware new services.

Introduction to special issue on context-aware web services for the future internet

Introduction to special issue on context-aware web services for the future internet