Intersection schemas as a dataspace integration technique

This paper introduces the concept of Intersection Schemas in the field of heterogeneous data integration and dataspaces. We introduce a technique for incrementally integrating heterogeneous data sources by specifying semantic overlaps between sets of extensional schemas using bidirectional schema transformations, and automatically combining them into a global schema at each iteration of the integration process. We propose an incremental data integration methodology that uses this technique and that aims to reduce the amount of up-front effort required. Such approaches to data integration are often described as pay-as-you-go. A demonstrator of our technique is described, which utilizes a new graphical user tool implemented using the AutoMed heterogeneous data integration system. A case study is also described, and our technique and integration methodology are compared with a classical data integration strategy

Visual exploration and retrieval of XML document collections with the generic system X2

This article reports on the XML retrieval system X2 which has been developed at the University of Munich over the last five years. In a typical session with X2, the user first browses a structural summary of the XML database in order to select interesting elements and keywords occurring in documents. Using this intermediate result, queries combining structure and textual references are composed semiautomatically. After query evaluation, the full set of answers is presented in a visual and structured way. X2 largely exploits the structure found in documents, queries and answers to enable new interactive visualization and exploration techniques that support mixed IR and database-oriented querying, thus bridging the gap between these three views on the data to be retrieved. Another salient characteristic of X2 which distinguishes it from other visual query systems for XML is that it supports various degrees of detailedness in the presentation of answers, as well as techniques for dynamically reordering and grouping retrieved elements once the complete answer set has been computed

A Taxonomy of Workflow Management Systems for Grid Computing

With the advent of Grid and application technologies, scientists and engineers are building more and more complex applications to manage and process large data sets, and execute scientific experiments on distributed resources. Such application scenarios require means for composing and executing complex workflows. Therefore, many efforts have been made towards the development of workflow management systems for Grid computing. In this paper, we propose a taxonomy that characterizes and classifies various approaches for building and executing workflows on Grids. We also survey several representative Grid workflow systems developed by various projects world-wide to demonstrate the comprehensiveness of the taxonomy. The taxonomy not only highlights the design and engineering similarities and differences of state-of-the-art in Grid workflow systems, but also identifies the areas that need further research.Comment: 29 pages, 15 figure

A Semantic Web Annotation Tool for a Web-Based Audio Sequencer

Music and sound have a rich semantic structure which is so clear to the composer and the listener, but that remains mostly hidden to computing machinery. Nevertheless, in recent years, the introduction of software tools for music production have enabled new opportunities for migrating this knowledge from humans to machines. A new generation of these tools may exploit sound samples and semantic information coupling for the creation not only of a musical, but also of a "semantic" composition. In this paper we describe an ontology driven content annotation framework for a web-based audio editing tool. In a supervised approach, during the editing process, the graphical web interface allows the user to annotate any part of the composition with concepts from publicly available ontologies. As a test case, we developed a collaborative web-based audio sequencer that provides users with the functionality to remix the audio samples from the Freesound website and subsequently annotate them. The annotation tool can load any ontology and thus gives users the opportunity to augment the work with annotations on the structure of the composition, the musical materials, and the creator's reasoning and intentions. We believe this approach will provide several novel ways to make not only the final audio product, but also the creative process, first class citizens of the Semantic We

BlogForever D2.6: Data Extraction Methodology

This report outlines an inquiry into the area of web data extraction, conducted within the context of blog preservation. The report reviews theoretical advances and practical developments for implementing data extraction. The inquiry is extended through an experiment that demonstrates the effectiveness and feasibility of implementing some of the suggested approaches. More specifically, the report discusses an approach based on unsupervised machine learning that employs the RSS feeds and HTML representations of blogs. It outlines the possibilities of extracting semantics available in blogs and demonstrates the benefits of exploiting available standards such as microformats and microdata. The report proceeds to propose a methodology for extracting and processing blog data to further inform the design and development of the BlogForever platform

Schema Mapper: A Visualization Tool for DL Integration

Schema mapping is a challenging problem. It has come to the fore in recent years; there are important applications like database schema integration and, more recently, digital library merging of heterogeneous data. Previous studies have approached the schema mapping process either from algorithmic or visualization perspectives, with few integrating both. With Schema Mapper we demonstrate a semi-automatic tool for schema integration that combines a novel visual interface with an algorithm-based recommendation engine. Schemas are visualized as hyperbolic trees (see Fig. 1), thus allowing more schema nodes to be displayed at one time. Matches to selections are recommended to the user, which makes the mapping operation easier and faster

Semantic annotation of Web APIs with SWEET

Recently technology developments in the area of services on the Web are marked by the proliferation of Web applications and APIs. The development and evolution of applications based on Web APIs is, however, hampered by the lack of automation that can be achieved with current technologies. In this paper we present SWEET - Semantic Web sErvices Editing Tool - a lightweight Web application for creating semantic descriptions of Web APIs. SWEET directly supports the creation of mashups by enabling the semantic annotation of Web APIs, thus contributing to the automation of the discovery, composition and invocation service tasks. Furthermore, it enables the development of composite SWS based applications on top of Linked Data

Integration of Heterogeneous Digital Libraries with Semi-automatic Mapping and Browsing: From Formalization to Specification to Visualization

In this paper, we formalize the digital library (DL) integration problem and propose an overall approach based on the 5S framework. We apply 5S to domain-specific (archaeological) DLs, illustrating our solutions for key problems in DL integration. We use ETANA-DL as a case study to describe the process of semi-automatically generating a union catalog and a unified browsing service in an archaeological DL. A visual schema mapping tool is developed for union catalog creation. A pilot user study aids tool evaluation. Our approach is further validated through application of a general browsing component to two integrated DLs