Monika Lanzenberger

AlViz - A Tool for Visual Ontology Alignment

We introduce a multiple-view tool called AlViz, which supports the alignment of ontologies visually. Ontologies play an important role for interoperability between organizations and for the semantic Web because they aim at capturing domain knowledge in a generic way and provide a consensual understanding of a domain. Alignment is the process where for each entity in first ontology we try to find a corresponding entity in the second ontology with the same or the closest meaning. Existing ontology alignment tools do not adequately provide a way for users to analyze the results. While many alignment tools generate lists of mappings it is difficult to analyze these alignments without examining every pairwise correspondence in the output files and even then it is an overwhelming task. We propose the use of visualization techniques to facilitate user understanding of the ontology alignment results. AlViz is implemented as a tab plug-in for Protege

Visualization in Ontology Tools

With a literature study we found an enormous number of ontology visualization tools. Many of them apply graph visualization but there are other approaches as well. We have identified interesting solutions for dealing with the complexity of large ontologies. Ontology engineering, ontology mapping and alignment can benefit from Information Visualization. Our collection is a starting point to demonstrate the usefulness of Information Visualization techniques, however, a detailed evaluation would be the next step to consolidate this research area and help to boost the adoption of ontologies in common Web applications.

Ontology Matching: Current Status, Dilemmas and Future Challenges

Ontology matching is still one of the hottest topics of Semantic Web research. The aim of this position statement is three-fold. Firstly, to briefly update the research community about the ldquowhere are we nowrdquo in ontology matching. Secondly, to trigger discussion on dilemmas and critical questions as these were recently identified in the latest ontology-matching-related research events. Thirdly, to comment on visible challenges that may influence the future of this hot topic and consequently the Semantic Web research in general, pointing on the ldquowhere shall we gordquo in the near future.

Visual ontology alignment for knowledge sharing and reuse

Purpose – By providing interoperability users can be supported in sharing and reusing vocabularies and knowledge. Ontology alignment plays an important role in the context of semantic interoperability. Usually ontology alignment tools generate results that are difficult to understand or assess. In order to enable users to check and improve alignment results and to understand their consequences information visualization techniques are used. The purpose of this paper is to discuss the relevant quality aspects in ontology alignment as well as current activities and available tools. Design/methodology/approach – Based on a literature study quality measures for ontology alignment identified and requirements for visual ontology alignment are defined. As a proof of concepts a prototype called AlViz was developed. Findings – Information visualization offers appropriate methods for the assessment of ontology alignment results. Different levels of detail and overview help users to navigate and understand the alignments. The assessment of semi-structured resources by users involves learning activities. The neighborhood of the entity under investigation bears relevant semantic information. Therefore, assessment may include crisscrossing acquisition of knowledge representations and their semantics. Originality/value – Along a comprehensive framework alignment assessment tasks are identified and visualization tool is introduced and applied which aims at making ontology alignment results manageable and comprehensible.

Applying information visualization techniques to capture and explore the course of cognitive behavioral therapy

Tracking and especially comparing psychotherapeutic processes is a complex task involving a large number of individual and complexly related parameters. Therefore, descriptive and classical statistical methods are only suited for partial analyses. To overcome these limitations we introduce LinkVis, a new Information Visualization (InfoVis) tool used to visualize and evaluate psychotherapeutic processes. LinkVis is developed and clinically tested on the basis of Cognitive Behavioral Therapy treating anorectic girls. The user gets new insight into the data under investigation due to the combination of three different visualization techniques: scatterplots, Chernoff faces, and parallel coordinates. LinkVis supports exploring of complex time-dependent data in order to gain more information about the psychotherapeutic process, especially when comparing different patients and groups.

iweightings: Enhancing Structure-based Ontology Alignment by Enriching Models with Importance Weighting

Structural ontology matching methods analyze mainly two factors: entity labels and relationships among entities. We propose to additionally consider an importance and relevance factor, which is determined by two indicators automatically calculated by a (simple) weighting method. This weighting factor represents the importance of a concept based on its information significance in the modeling context and, additionally, its relevance for structure-based alignment depending on the number of relationships this concept participates in quantified by the rweighting indicator. The method starts via a manually weighting annotation of relationships among concepts conducted by ontology engineers during the ontology development process. Our approach is an assistance mechanism to improve the ontology alignment process and to enhance the cognitive support for users. Thus, ontology alignment becomes already important ex ante when the ontology development process starts, unlike other alignment techniques, which consider only ex post knowledge.

Facilitating Interoperability in Semantic Web Applications Using Ontologies

Semantic Web applications often rely on the reuse of underlying data from legacy information systems. The motivation for our research is how to make this data accessible for use in such applications. We propose the use of ontologies and conceptual modelling in an overall approach for data interoperability. The approach incorporates a process for ontology alignment using our tool for visual ontology alignment. First results from our tool evaluation were promising and show that visualization is useful for locating additional candidate alignments by an end user.