Multilevel analysis for agent-based service composition

SummaryToday, service composition is emerging paradigm on the communication networks such as cloud environments, internet of things, wireless sensor network, and software‐defined network. The goal of service composition method is to provide the interactions between user requirements and smart objects of intelligent communication systems. There have been many efforts to use formal verification and behavioral modeling methods to evaluate the service composition mechanisms. Up to now, there is not a comprehensive analysis research on this topic. Therefore, this paper focuses on several formal verification approaches that are performed to confirm the service composition correctness in communication networks. The objective of this paper is to comprehensively categorize and examine current research techniques on formal verification of the service composition. This research analysis provides an overview of recent service composition approaches according to structural and functional properties. Comparison results show that most of the verification approaches in explanation of the service composition correctness are semantic‐aware approach with 43%. The most used verification method for the service composition is model checking with 69%. The process algebra is used 29%, and some theorem proving methods are applied in 9% of the investigated mechanism. Moreover, most widely used modeling tools are NuSMV (22%), SPIN (17%), CPN (12%), UPPAAL (12%), Event‐B (10%), and PAT (5%).

Exploiting composition of mobile devices for maximizing user QoS under energy constraints in mobile grid

Composing several API-defined services into one composite service per user requirements has become an important service creation approach in the cloud-enabled API economy. Various service selection approaches in support of service composition on demand have been proposed. They usually assume that networking resources are over-provisioned and their usage needs not be considered when making quality-aware service composition decisions. In practice, these approaches often lead to wasteful network resource consumption and impractical end-to-end QoS optimality for cloud-based services. This paper proposes a network-aware cloud service composition approach, named NetMIP, with comparative experimental evaluations for the clouds that adopt the widely deployed fat-tree network topology. By formalizing the service composition goal as a multi-objective constraint optimization problem, we have validated the proposed approach can be used to effectively reduce network resource consumption and deliver QoS optimality while satisfying the end-to-end QoS constraints for the candidate composite services in the cloud. The comparative experimental evaluations are done via a credible cloud infrastructure simulation system, named WebCloudSim. Extensive evaluation results show that NetMIP outperforms several representative cloud service composition approaches in terms of network resource consumption, QoS optimality, and computation time under various service selection workloads and fat-tree network topology settings.

This study explores the possible strategy for the cultivation of international language service talents in higher education in China to resolve the urgent need for enhancing emergency language services for the hearing-impaired population, which is a necessity highlighted especially during the Coronavirus pandemic. The study evaluates the current research and services to identify the absence of tailored solutions for users of sign languages. This study suggests that higher education institutions should focus on developing specialized talents through interdisciplinary studies, practical training, and standardization building, aimed at overcoming communication barriers for the hearing-impaired and ensuring equitable access to emergency services.

Service composition combines a set of available Web services using control flows to create a more complex service. The service composition is a complex process which is challenging even for experienced users to discover and select appropriate service among a set of similar services. The available tools and techniques for service composition either are too complicated or require technical knowledge (such as script language). Moreover the heterogeneity in service description language and communication protocols make service composition more difficult. In our research, we propose an approach that allows non-technical users (i.e., end users) to easily compose heterogeneous Web resources with different communication protocol. The goal of this research is fulfilled on two stages: 1) identifying integrable Web resources from different Web applications and SOAP-based Web services; and 2) providing approaches to discover and compose Web resources that are capable of accomplishing user's activities. We propose a framework that assists a user to discover and compose services.

Current Web service technologies provide a set of well-defined syntaxes of service discovery, composition, and invocation. However, they lack the support for semantic interoperability and personalization. This paper briefly an agent-driven, P2P-based, distributed service registry architecture referred to as the personalized Web service architecture (PWSA) that supports personal-based service discovery, composition, and invocation. A prototype implementation and a performance analysis study of PWSA demonstrate the self-organization property of the architecture and its scalability in terms of the number of services and the number of search queries executed by user agents.

Composition of Cloud services is necessary when a single component is unable to satisfy all the user's requirements. It is a complex task for Cloud managers which involves several operations such as discovery, compatibility checking, selection, and deployment. Similarly to a non Cloud environment, the service composition raises the need for design-time approaches to check the correct interaction between the different components of a composite service. However, for Cloud-based service composition, new specific constraints, such as resources management, elasticity and multitenancy have to be considered. In this work, we use Symbolic Observation Graphs (SOG) in order to abstract Cloud services and to check the correction of their composition with respect to event- and state-based LTL formulae. The violation of such formulae can come either from the stakeholders' interaction or from the shared Cloud resources perspectives. In the former case, the involved services are considered as incompatible while, in the latter case, the problem can be solved by deploying additional resources. The approach we propose in this paper allows then to check whether the resource provider service is able, at run time, to satisfy the users' requests in terms of Cloud resources.

Service-Oriented Computing (SOC) is a new computing paradigm that utilizes service to support the development of rapid, low-cost and easy composition. SOC promotes creation of new services by composition. In the composition process, requirements are described by requestor and Web service offered by the provider, a provider is the owner of service his role is to create service and publish it to make it available to customers and partners. A number of Web services compositions approaches have been presented to satisfy the end user's requirements. Interactive Web services compositions (IWSC) creates new value by adapting the end-user's requirements, the end-user corresponds to the person requesting the service and who will search and invoke the service. With the emergence of collective intelligence (CI), IWSC allows a better end-user's satisfaction. In this paper, we propose a new approach that supports Collective intelligence for satisfying the actor's requirements that suggests a model to help the web services composition. Our approach uses the beneficial roles of collaboration as a key for future services composition. It uses also the interactivity between the actors, user interaction during a service composition will contribute in the satisfaction degree of the actors.

A service invocation in a composite service is usually defined by its interface for abstraction. Once the interface is standardized and many services which have the same interface become available, a user can bind preferable ones to the composite service only by setting endpoints. Since new services become available day by day in open environment, it is crucial to automatically construct the bindings according to user's requirements. However, runtime binding construction often degrades the performance because searching a vast amount of possible bindings is time-consuming. Moreover, bindings need to be modified even during execution of a composite service when some adaptation process is applied. In this paper, we proposed a framework for constructing bindings, which is based on ATMS (Assumption-based Truth Maintenance System). The framework effectively caches possibilities of bindings and can manage changes of bindings when a runtime adaptation process is applied. We implemented a prototype of the framework and confirmed that it works fast enough for a real scale service composition.

Nowadays new systems for electronic service delivery are comprised of components. These components may be locally developed, managed and optimized and not intended to be reused in composite applications. By compositing modular components in new systems large, distributed systems can be developed in which services provided by various stakeholders are combined. The creation of service compositions is an ill-posed and ill-structured design problem which must be tackled with great care and should take into account the various stakeholders and their technological systems.In this paper we present a socio-technical design approach for developing service compositions. This approach starts with analyzing both user requirements and analyzing available services. This is in contrast with existing approaches, which are primarily supply-driven, i.e. they take the available services as a starting point. In addition, the individual service components need to be coordinated to create a coherent composition. Therefore, the dependencies among components are analyzed which help to identify feasible and alternative compositions and enable communication and negotiation among stakeholders. We found that the dependencies among systems components are often viewed as simple sequential, connections whereas, they might not be. Moreover, it was found that a method focused on technical design alone, like most current composition approach, will be insufficient and that stakeholder-related social aspects need to be considered. A service compositions approach in organizational networks requires a high degree of stakeholder participation.

In the Web Service world, it is an important technique that taking the usable behaviors in the existed web services provides some value-added functions by the service composition. Therefore, the usability analysis of web service behaviors is a significant problem to be solved. Based on our early study about behavior derivation for software components by interface automata (IA), a method is given for checking whether there are usable behaviors in a web service or not according to a user's requirement. A behavior is usable if it can be preserved in a composite web service under some constraints, otherwise it is unusable. Web services are described by BPEL4WS and the user's requirements are specified by MSCs. The key step in our proposal is to build an IA model for the web service behaviors. Thus, we give the transformation rules from BPEL4WS to IA. By using the algorithm of constructing an environment for an IA which had been given in our early works, the usability of a web service behaviors is checked. A case study from real application is used to validate our proposal.

Service-Oriented Architecture enables users, both ordinary end users and IT professionals, to be part of the development cycle of interactive service-based systems in order to fulfil their desired needs. In this paper we explore and compare the mental model of two different categories of users towards the idea of “service composition by end users”. Participants’ responses are concluded from 5 separate focus groups, including a total of 64 participants. Results have shown that both groups of users are highly interested in the composition of service-based systems; however, privacy and security concerns and technical complexity of current approaches and service composition environments hinder the diffusion of service-based technologies among users. In this respect, this paper proposes a preliminary model of service composition uptake by end users and discusses user views and requirements to facilitate service composition.

One of the major goals of Web services is to make easier their composition to form more complex services, modeled as workflows. A key role in the Web services composition is the selection of a proper service for each activity in the workflow. In general, this requires the exchange of sensitive information of users, requiring the composition, as well as of involved service providers. So far this problem has been investigated in the setting of orchestrated service composition, under the assumption of the presence of a broker coordinating the composition. However, a promising alternative approach is the one of choreography, where each service involved in the service composition has to locally manage service selection and invocation. In this paper, we propose a framework to enforce user and provider requirements in the scenario of service choreography in a privacy-preserving way, that is, without the releasing of any private information of users and providers. To achieve this result we make use of different privacy-preserving protocols. As it will be shown in the paper, the proposed solution does not implies relevant overhead.

Acquiring a foreign language requires a student to master the two elements of language, vocabulary and grammar, and the four language skills, listening, speaking, reading, and writing. Within each skill, these two language elements play a considerably essential role since they are seen as the very core aspects of language learning and that they are regarded inherent in each of these skills. Thus, vocabulary and grammatical aspects cannot be separated from the four language skills in language acquisition as without any one of which each skill is never acquired. Since the implementation of communicative approach in 1984 to the application of the competency-based language teaching in Indonesia, English programs at high schools have been meaning or message based rather than language usage or form oriented. As a result, grammar learning has been significantly kept aside if not totally ignored in class interactions, and that communication success becomes the main target in instructional objectives. This study attempts to map grammatical errors the students make in their speech productions. It employs an interview technique for data collection by recording the conversations of twenty respondents - - junior and senior students - - on a selected issue of a particular topic and transcribing them in the form of written transcripts which are then to be analyzed from a grammatical perspective with the reference of grammar books. Those violating the grammatical norms will be considered as grammatical errors. It has been found out that learners’ grammatical errors are derived from two major causes - - translating concepts of L1 into L2 and their approximative system. This study concludes that the communicative classrooms which utilize the competency-based language teaching bring about a positive impact upon grammar learning. This research is significant as it gives a great contribution to structure and speaking class teachers, students, as well as to the department for policy making.

Automatically composing service-based software solutions is a challenging task. Considering context information during this service composition process is even more challenging. In domains such as image processing, however, context-sensitivity is inherent and cannot be ignored when developing techniques for automatic service composition. Formal approaches tend to create ambiguous solutions, whenever the expressive power of the applied formalism is limited. For example, services may have the same formal specification, although their actual functionality depends on the concrete context. In order to satisfy individual user requests while providing data-dependent functionality, formal approaches have to be extended. We propose to incorporate Reinforcement Learning techniques and combine them with planning based composition approaches. While planning ensures formally correct solutions, learning enables the composition process to resolve ambiguity by implicitly considering context information. Preliminary results show that our combined approach adapts to a static context while still satisfying formally specified requirements.