End-user Service Composition Research Articles

AN INTEGRATED THREE-FLOW APPROACH FOR FRONT-END SERVICE COMPOSITION

End-User Service Composition (EUSC) aims to enable end-user programmers who are not professional developers develop applications by composing or aggregating existing web services. Despite the effort, studies have shown that, end-user programmers are not able to deal with the technical complexities involved in EUSC. One way to deal with this issue is Front-End Service Composition (FESC), which allows end-user programmers to compose web services at the presentation layer of an application by configuring user interface (UI) widgets that represent the back-end web services. However, there are not many studies on FESC and the existing ones suffer two main problems, namely, lack of control flow and/or application flow visualization, and they still require end-user programmers to have certain technical knowledge in the service composition process that these end-user programmers generally do not possess. Following that, this study proposes an integrated three-flow approach (application flow, control flow and data flow) to deal with the current limitations of FESC. The approach generates the GUI of web services automatically, thus allowing the UI of the application to be developed at the same time the required web services are assembled. The approach allows end-user programmers to explicitly configure the three different types of flows involved in service composition. A proof-of-concept prototype, QuickWSC, that incorporates the three-flow approach was developed. It adopts a side-by-side multiple-view design to support visual configuration of the three flows in an uncluttered yet synchronized manner that adhered to established design guidelines. A user evaluation study was conducted on QuickWSC. The results show that it is easy to compose web services by explicitly specifying the three flows, that the configurations of the three flows integrated in the two views helps in composing application from web services, and that no technical knowledge is required to use QuickWSC

User Studies on End-User Service Composition

Context: End-user service composition (EUSC) is a service-oriented paradigm that aims to empower end users and allow them to compose their own web applications from reusable service components. User studies have been used to evaluate EUSC tools and processes. Such an approach should benefit software development, because incorporating end users’ feedback into software development should make software more useful and usable. Problem: There is a gap in our understanding of what constitutes a user study and how a good user study should be designed, conducted, and reported. Goal: This article aims to address this gap. Method: The article presents a systematic review of 47 selected user studies for EUSC. Guided by a review framework, the article systematically and consistently assesses the focus, methodology and cohesion of each of these studies. Results: The article concludes that the focus of these studies is clear, but their methodology is incomplete and inadequate, their overall cohesion is poor. The findings lead to the development of a design framework and a set of questions for the design, reporting, and review of good user studies for EUSC. The detailed analysis and the insights obtained from the analysis should be applicable to the design of user studies for service-oriented systems as well and indeed for any user studies related to software artifacts.

Establishing requirements for End-user Service Composition tools

End-user Service Composition (EUSC) is defined as service composition where the person who creates the composite service also uses it. We derived requirements for EUSC tools using a custom method based on the scenario-based requirements analysis method. Ten participants were given scenarios, a demonstrator application and examples of EUSC tools before being interviewed. Analysing their responses, we elicited 139 requirements across topics including service “types” (e.g. pervasive services), composition flow (i.e. control/data flow) and the use of templates in composition. This is the first published work to have used a robust requirements analysis method in EUSC, adapted specifically to take account of prior work on EUSC. Some of our requirements validate those found in prior research or current EUSC tools but many are unique to our findings. The requirements found in this work inform and inspire the development of future EUSC tools, and the methodology is easily adapted for application in other domains.

Service Composition for End-Users

RESTful services are becoming a popular technology for providing and consuming cloud services. The idea of cloud computing is based on on-demand services and their agile usage. This implies that also personal service compositions and workflows should be supported. Some approaches for RESTful service compositions have been proposed. In practice, such compositions typically present mashup applications, which are composed in an ad-hoc manner. In addition, such approaches and tools are mainly targeted for programmers rather than end-users. In this paper, a user-driven approach for reusable RESTful service compositions is presented. Such compositions can be executed once or they can be configured to be executed repeatedly, for example, to get newest updates from a service once a week.

Ontology-driven service composition for end-users

Current service composition techniques and tools are mainly designed for use by Service-Oriented Architecture (SOA) professionals to solve business problems. Little attention has been paid to allowing end-users without sufficient service composition skills to compose services and integrate SOA solutions into their online experience to fulfill their daily activities. To shelter end-users from the complexity of service composition, we propose an approach which can compose services on the fly to meet the situational needs of end-users. We present a tag-based service description schema which allows non-IT professional users to easily understand the description of services and add their own descriptions using descriptive tags. Instead of requiring end-users to specify detailed steps for composition, the end-users only need to describe their goals using a few keywords. Our approach expands the meaning of a user's goal using ontologies then derives a group of keywords to discover services in order to fulfill the goal. A prototype is developed as a proof of concept to show that our approach enables end-users to discover and compose services easily. We conduct a case study to evaluate the effectiveness of our approach that eases end-users to compose services without the knowledge of SOA technologies. The results of our case study show that our approach can effectively generate ad-hoc processes and discover services with relatively high precision and recall.