Hypermedia-based discovery for source selection using low-cost linked data interfaces

Evaluating federated Linked Data queries requires consulting multiple sources on the Web. Before a client can execute queries, it must discover data sources, and determine which ones are relevant. Federated query execution research focuses on the actual execution, while data source discovery is often marginally discussed-even though it has a strong impact on selecting sources that contribute to the query results. Therefore, the authors introduce a discovery approach for Linked Data interfaces based on hypermedia links and controls, and apply it to federated query execution with Triple Pattern Fragments. In addition, the authors identify quantitative metrics to evaluate this discovery approach. This article describes generic evaluation measures and results for their concrete approach. With low-cost data summaries as seed, interfaces to eight large real-world datasets can discover each other within 7 minutes. Hypermedia-based client-side querying shows a promising gain of up to 50% in execution time, but demands algorithms that visit a higher number of interfaces to improve result completeness

A case study for measuring informal learning in PLEs

The technological support for learning and teaching processes is constantly changing. Information and Communication Technologies (ICT) applied to education, cause changes that affect the way in which people learn. This application introduces new software systems and solutions to carry out teaching and learning activities. Connected to ICT application, the emergence of Web 2.0 and its use in learning contexts enables an online implementation of the student-centred learning paradigm. In addition, 2.0 trends provide “new” ways to exchange, making easier for informal learning to become patent. Given this context, open and user-centered learning environments are needed to integrate such kinds of tools and trends and are commonly described as Personal Learning Environments. Such environments coexist with the institutional learning management systems and they should interact and exchange information between them. This interaction would allow the assessment of what happens in the personal environment from the institutional side. This article describes a solution to make the interoperability possible between these systems. It is based on a set of interoperability scenarios and some components and communication channels. In order to test the solution it is implemented as a proof of concept and the scenarios are validated through several pilot experiences. In this article one of such scenarios and its evaluation experiment is described to conclude that functionalities from the institutional environments and the personal ones can be combined and it is possible to assess what happens in the activities based on them.Peer ReviewedPostprint (published version

Analysis and Verification of Service Interaction Protocols - A Brief Survey

Modeling and analysis of interactions among services is a crucial issue in Service-Oriented Computing. Composing Web services is a complicated task which requires techniques and tools to verify that the new system will behave correctly. In this paper, we first overview some formal models proposed in the literature to describe services. Second, we give a brief survey of verification techniques that can be used to analyse services and their interaction. Last, we focus on the realizability and conformance of choreographies.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330

Google Web APIs - an Instrument for Webometric Analyses?

This paper introduces Google Web APIs (Google APIs) as an instrument and playground for webometric studies. Several examples of Google APIs implementations are given. Our examples show that this Google Web Service can be used successfully for informetric Internet based studies albeit with some restrictions.Comment: 2 pages, 2 figures, 10th International Conference of the International Society for Scientometrics and Informetric