Nadine Ludwig

WhoKnows? Evaluating linked data heuristics with a quiz that cleans up DBpedia

Purpose – Linking Open Data (LOD) provides a vast amount of well structured semantic information, but many inconsistencies may occur, especially if the data are generated with the help of automated methods. Data cleansing approaches enable detection of inconsistencies and overhauling of affected data sets, but they are difficult to apply automatically. The purpose of this paper is to present WhoKnows?, an online quiz that generates different kinds of questionnaires from DBpedia data sets.Design/methodology/approach – Besides its playfulness, WhoKnows? has been developed for the evaluation of property relevance ranking heuristics on DBpedia data, with the convenient side effect of detecting inconsistencies and doubtful facts.Findings – The original purpose for developing WhoKnows? was to evaluate heuristics to rank LOD properties and thus, obtain a semantic relatedness between entities according to the properties by which they are linked. The presented approach is an efficient method to detect popular prop...

Virtual Room Concepts for Cooperative, Scientific Work

Cooperative knowledge spaces offer new potentials for experimental and scientific work in the current fields of engineering and natural sciences. Widely accepted content management systems often only provide simple content in combination with communication tools; cooperative knowledge spaces are able to project the concept of natural cooperative work onto virtual rooms. In this article we introduce our concept of virtual rooms for scientific and educational work. We describe requirements for complex cooperative work in virtual knowledge spaces where the rooms are arranged in a dynamic, heterogeneous network and incorporate experimental laboratory equipment, shared whiteboards and version‐controlled documents. We developed this concept in the context of our project ViCToR‐Spaces (Virtual Cooperation in Teaching and Research for Mathematics and Natural Sciences) and are currently implementing some of the parts of the concept. Index Terms ‐ cooperative knowledge spaces, virtual and remote laboratories, virtual rooms, cooperative education and work

Named Entity Recognition for User-Generated Tags

Content Based Multimedia Retrieval on nontextual documents is often constrained by available metadata. User-generated tags constitute an important source of information about a resource. To enable search scenarios exceeding traditional text-based search, such as exploratory and semantic search, this textual information must be complemented with semantic entities. Due to tag ambiguities and creative neologisms automatic semantic annotation based on user tags represents a major challenge. In this work, we show how to adopt context information and ontological knowledge to automatically assign semantic entities to user-generated tags for video data. Thus, a sophisticated semantic search on semantic entities is enabled. The algorithm combines co-occurence and link graph analysis using Linked Data. Also, a definition of context reliability in audio-visual content is described.

Use what you have: Yovisto video search engine takes a semantic turn

The phenomenal increase of online video content confronts the consuming user with an immeasurable amount of data which can only be accessed with sophisticated multimedia search and management technologies. Usual video search engines provide a keyword-based search, where lexical ambiguity of natural language often leads to imprecise and incomplete results. Semantics of keywords and metadata has to be determined to overcome these shortcomings to provide high precision and high recall. In this work, we show how to gradually transform the video search engine Yovisto from a simple keyword-based search engine to a fullyfledged semantic video search engine simply by using the existing search engine infrastructure based on Lucene augmented by simple semantic metadata.

Victor-Spaces: Virtual and Remote Experiments in Cooperative Knowledge Spaces

Cooperative knowledge spaces create new potentials for the experimental fields in natural sciences and engineering because they enhance the accessibility of experimental setups through virtual laboratories and remote technology, opening them for collaborative and distributed usage. A concept for extending existing virtual knowledge spaces for the means of the technological disciplines (“ViCToR-Spaces” – Virtual Cooperation in Teaching and Research for Mathematics, Natural Sciences and Engineering) is presented. The integration of networked virtual laboratories and remote experiments will be described.

Modularization and semantics of learning objects in a cooperative knowledge space

The last couple of years have shown that eLearning is not accomplished by simply providing pdf or ppt files on the Internet. Learning concepts have to tie in with technical implementations so as to generate the added value that will lead students to actually make use of the advantages of digital learning. The contents of such a system must not be isolated but should draw connections to a variety of other topics. This would ensure a holistic education and at the same time ensure the semantic coherence of a larger number of lectures especially in engineering and the natural sciences.

Networked Experiments and Scientific Resource Sharing in Cooperative Knowledge Spaces.

Cooperative knowledge spaces create new potentials for the experimental fields in natural sciences and engineering because they enhance the accessibility of experimental setups through virtual laboratories and remote technology, opening them for collaborative and distributed usage. A concept for extending existing virtual knowledge spaces for the means of the technological disciplines (VICToR-Spaces-virtual cooperation in teaching and research for mathematics, natural sciences and engineering) is presented. The integration of networked virtual laboratories and remote experiments (NanoLab Approach), as well as an approach to community-driven content sharing and content development within virtual knowledge spaces (NanoWiki) are described

Work in Progress: Visualizing a Semantic Search in a Room-Based Knowledge Space

A semantic network acts as an expedient foundation to search for objects in a cooperative room-based knowledge space. But to make the search results useable and give users an intuitive instrument the search interface has to stick to several principles of usability and the search results have to be visualized in an appropriate way. The paper proposed is dealing with the problems related to the visualization of semantic networks and provides a concept for this field of research. This concept includes the analysis of different navigation designs as well as a comparison of different alternative presentations of search results.