Configuring Semantic Web Interfaces by Data Mapping

We demonstrate how to develop Web-based user interfaces for Semantic Web applications using commonly available, off-the-shelf Web widget libraries. By formally defining the underlying data model that is assumed by these widgets, Semantic Web application developers can use familiar RDF constructs to map their own data to the model implemented by the Widgets. As an example, we briefly describe the interface model underlying our own framework, and provide concrete examples showing how it has been used to create Semantic Web applications in two different domains. We conclude by discussing the advantages and limitations of our approach

/facet: A browser for heterogeneous semantic web repositories

Facet browsing has become popular as a user friendly interface to data repositories. We extend facet browsing of Semantic Web data in four ways. First, users are able to select and navigate through facets of resources of any type and to make selections based on properties of other, semantically related, types. Second, we address a disadvantage of hierarchy-based navigation by adding a keyword search interface that dynamically makes semantically relevant suggestions. Third, the interface of our browser, /facet, allows the inclusion of facet-specific display options that go beyond the hierarchical navigation that characterizes current facet browsing. Fourth, the browser works on any RDFS dataset without any additional configuration. These properties make /facet an ideal tool for Semantic Web developers that need a instant interface to their complete dataset. The automatic facet configuration generated by the system can then be further refined to configure it as a tool for end users. The implementation is based on current Web standards and open source software. The new functionality we provide is motivated using a scenario from the cultural heritage domai

Using Prolog as the Fundament for Applications on the Semantic Web

This article describes the experiences developing a Semantic Web application entirely in Prolog. The application, a demonstrator that provides access to multiple art collections and linking these using cultural heritage vocabul

Indications for grain growth and mass decrease in cold dust disks around Classical T Tauri stars in the MBM 12 young association

We report detection of continuum emission at 850 and 450 micron from disks around four Classical T Tauri stars in the MBM 12 (L1457) young association. Using a simple model we infer masses of 0.0014-0.012 M_sun for the disk of LkHa 263 ABC, 0.005-0.021 M_sun for S18 ABab, 0.03-0.18 M_sun for LkHa 264 A, and 0.023-0.23 M_sun for LkHa 262. The disk mass found for LkHa 263 ABC is consistent with the 0.0018 M_sun inferred from the scattered light image of the edge-on disk around component C. Comparison to earlier 13CO line observations indicates CO depletion by up to a factor 300 with respect to dark-cloud values. The spectral energy distributions (SED) suggest grain growth, possibly to sizes of a few hundred micron, but our spatially unresolved data cannot rule out opacity as an explanation for the SED shape. Our observations show that these T Tauri stars are still surrounded by significant reservoirs of cold material at an age of 1-5 Myr. We conclude that the observed differences in disk mass are likely explained by binary separation affecting the initial value. With available accretion rate estimates we find that our data are consistent with theoretical expectations for viscously evolving disks having decreased their masses by ~30%.Comment: 15 pages, 3 figures, uses aastex. ApJ Letters, in pres

Thesaurus-based search in large heterogeneous collections

In cultural heritage, large virtual collections are coming into existence. Such collections contain heterogeneous sets of metadata and vocabulary concepts, originating from multiple sources. In the context of the E-Culture demonstrator we have shown earlier that such virtual collections can be effectively explored with keyword search and semantic clustering. In this paper we describe the design rationale of ClioPatria, an open-source system which provides APIs for scalable semantic graph search. The use of ClioPatria’s search strategies is illustrated with a realistic use case: searching for ”Picasso”. We discuss details of scalable graph search, the required OWL reasoning functionalities and show why SPARQL queries are insufficient for solving the search problem

ClioPatria: A SWI-Prolog Infrastructure for the Semantic Web

ClioPatria is a comprehensive semantic web development framework based on SWI-Prolog. SWI-Prolog provides an efficient C-based main-memory RDF store that is designed to cooperate naturally and efficiently with Prolog, realizing a flexible RDF-based environment for rule based programming. ClioPatria extends this core with a SPARQL and LOD server, an extensible web frontend to manage the server, browse the data, query the data using SPARQL and Prolog and a Git-based plugin manager. The ability to query RDF using Prolog provides query composition and smooth integration with application logic. ClioPatria is primarily positioned as a prototyping platform for exploring novel ways of reasoning with RDF data. It has been used in several research projects in order to perform tasks such as data integration and enrichment and semantic search

Generating Semantic Snapshots of Newscasts Using Entity Expansion

textabstractTV newscasts report about the latest event-related facts occurring in the world. Relying exclusively on them is, however, insufficient to fully grasp the context of the story being reported. In this paper, we propose an approach that retrieves and analyzes related documents from the Web to automatically generate semantic annotations that provide viewers and experts comprehensive information about the news. We detect named entities in the retrieved documents that further disclose relevant concepts that were not explicitly mentioned in the original newscast. A ranking algorithm based on entity frequency, popularity peak analysis, and domain experts’ rules sorts those annotations to generate what we call Semantic Snapshot of a Newscast (NSS). We benchmark this method against a gold standard generated by domain experts and assessed via a user survey over five BBC newscasts. Results of the experiments show the robustness of our approach holding an Average Normalized Discounted Cumulative Gain of 66.6%

Waisda?: video labeling game

The Waisda? video labeling game is a crowsourcing tool to collect user-generated metadata for video clips. It follows the paradigm of games-with-a-purpose, where two or more users play against each other by entering tags that describe the content of the video. Players score points by entering the same tags as one of the other players. As a result each video that is played in the game is annotated with tags that are anchored to a time point in the video. Waisda? has been deployed in two projects with videos from Dutch broadcasters. With the open source version of Waisda? crowdsourcing of video annotation becomes available for any online video collection