Ansgar Scherp

F--a model of events based on the foundational ontology dolce+DnS ultralight

The lack of a formal model of events hinders interoperability in distributed event-based systems. In this paper, we present a formal model of events, called Event-Model-F. The model is based on the foundational ontology DOLCE+DnS Ultralight (DUL) and provides comprehensive support to represent time and space, objects and persons, as well as mereological, causal, and correlative relationships between events. In addition, the Event-Model-F provides a flexible means for event composition, modeling event causality and event correlation, and representing different interpretations of the same event. The Event-Model-F is developed following the pattern-oriented approach of DUL, is modularized in different ontologies, and can be easily extended by domain specific ontologies.

Semantic Multimedia

Multimedia constitutes an interesting field of application for Semantic Web and Semantic Web reasoning, as the access and management of multimedia content and context depends strongly on the semantic descriptions of both. At the same time, multimedia resources constitute complex objects, the descriptions of which are involved and require the foundation on sound modeling practice in order to represent findings of low- and high level multimedia analysis and to make them accessible via Semantic Web querying of resources. This tutorial aims to provide a red thread through these different issues and to give an outline of where Semantic Web modeling and reasoning needs to further contribute to the area of semantic multimedia for the fruitful interaction between these two fields of computer science.

SemaPlorer-Interactive semantic exploration of data and media based on a federated cloud infrastructure

SemaPlorer is an easy to use application that allows end users to interactively explore and visualize a very large, mixed-quality and semantically heterogeneous distributed semantic data set in real-time. Its purpose is to acquaint oneself about a city, touristic area, or other area a user is interested in. By visualizing the data using a map, media, and different context views, SemaPlorer advances beyond simple storage and retrieval of large numbers of triples, as the interaction with the large data set is driven by the user. SemaPlorer leverages different semantic data sources such as DBpedia, GeoNames, WordNet, and personal FOAF files. These make a significant portion of the data provided for the Billion Triple Challenge. SemaPlorer intriguingly connects with a large Flickr data set converted to RDF. The storage infrastructure bases on Amazons Elastic Computing Cloud (EC2) and Simple Storage Service. We apply NetworkedGraphs as a conceptual layer on top of EC2, realizing a large, federated data infrastructure for semantically heterogeneous data sources from within and outside of the cloud. Therefore, the application is scalable with respect to the amount of distributed components working together as well as the number of triples managed overall. Hence, SemaPlorer is flexible enough to leverage for exploration of almost arbitrary additional data sources that might be added in the future. We conducted a formative evaluation of the SemaPlorer application with 20 test subjects. The results of this evaluation are analyzed and their implication to future work discussed. SemaPlorer won the first prize at the Billion Triple Challenge of the International Semantic Web Conference in Karlsruhe, 2008.

SchemEX - Efficient construction of a data catalogue by stream-based indexing of linked data

We present SchemEX, an approach and tool for a stream-based indexing and schema extraction of Linked Open Data (LOD) at web-scale. The schema index provided by SchemEX can be used to locate distributed data sources in the LOD cloud. It serves typical LOD information needs such as finding sources that contain instances of one specific data type, of a given set of data types (so-called type clusters), or of instances in type clusters that are connected by one or more common properties (so-called equivalence classes). The entire process of extracting the schema from triples and constructing an index is designed to have linear runtime complexity. Thus, the schema index can be computed on-the-fly while the triples are crawled and provided as a stream by a linked data spider. To demonstrate the web-scalability of our approach, we have computed a SchemEX index over the Billion Triples Challenge (BTC) dataset 2011 consisting of 2,170 million triples. In addition, we have computed the SchemEX index on a dataset with 11 million triples. We use this smaller dataset for conducting a detailed qualitative analysis. We are capable of locating relevant data sources with recall between 71% and 98% and a precision between 74% and 100% at a window size of 100 K triples observed in the stream and depending on the complexity of the query, i.e. if one wants to find specific data types, type clusters or equivalence classes.

Unlocking the semantics of multimedia presentations in the web with the multimedia metadata ontology

The semantics of rich multimedia presentations in the web such as SMIL, SVG, and Flash cannot or only to a very limited extend be understood by search engines today. This hampers the retrieval of such presentations and makes their archival and management a difficult task. Existing metadata models and metadata standards are either conceptually too narrow, focus on a specific media type only, cannot be used and combined together, or are not practically applicable for the semantic description of rich multimedia presentations. In this paper, we propose the Multimedia Metadata Ontology (M3O) for annotating rich, structured multimedia presentations. The M3O provides a generic modeling framework for representing sophisticated multimedia metadata. It allows for integrating the features provided by the existing metadata models and metadata standards. Our approach bases on Semantic Web technologies and can be easily integrated with multimedia formats such as the W3C standards SMIL and SVG. With the M3O, we unlock the semantics of rich multimedia presentations in the web by making the semantics machine-readable and machine-understandable. The M3O is used with our SemanticMM4U framework for the multi-channel generation of semantically-rich multimedia presentations.

Semantics, content, and structure of many for the creation of personal photo albums

Photos are often a means to remember personal events, and the creation of photo albums is the attempt to preserve our memories in a nice book. For a long time people have been creating such photo albums on the basis of prints from analog photos arranged in an album book with scissors and glue and annotated with comments and captions - a tedious task which in these days is getting support by authoring tools and digitally mastered photo books. Relying on the content of others such as printed travel guides, news papers, leaflets, but also friends and family the personal content often has been enriched, enhanced, and completed. This is the starting point of our work: with digital photography and the increasing amount of content-based and contextual metadata of personal photos we can now use this metadata to actually support the targeted and semi-automatic inclusion of interesting, related information from content of others, e.g., from Web 2.0 communities, and offer and add it at the right spot in the personal album. In this paper, we show how photo album creation can benefit from leveraging information learned from many users in regard of the albums content, structure, and semantics.

Designing core ontologies

One of the key factors that hinders integration of distributed, heterogeneous information systems is the lack of a formal basis for modeling the complex, structured knowledge that is to be exchanged. To alleviate this situation, we present an approach based on core ontologies. Core ontologies are characterized by a high degree of axiomatization and formal precision. This is achieved by basing on a foundational ontology. In addition, core ontologies should follow a pattern-oriented design approach. By this, they are modular and extensible. Core ontologies allow for reusing the structured knowledge they define as well as integrating existing domain knowledge. The structured knowledge of the core ontologies is clearly separated from the domain-specific knowledge. Such core ontologies allow for both formally conceptualize their particular fields and to be flexibly combined to cover the needs of concrete, complex application domains. Over the last years, we have developed three independent core ontologies for events and objects, multimedia annotations and personal information management. In this paper, we present the simultaneous use and integration of our core ontologies at the example of a complex, distributed socio-technical system of emergency response. We describe our design approach for core ontologies and discuss the lessons learned in designing them. Finally, we elaborate on the beauty aspects of our core ontologies.

Generic support for personalized mobile multimedia tourist applications

Mobile applications such as mobile tourist guides that provide tourists with location-based information today mostly aim to adapt the multimedia content to the different end user devices. More and more, these applications also exploit positioning information like GPS to guide the user on the trip. What is still lacking, however, is a <i>personalization</i> of the content to the interests and preferences of the individual tourist and the characteristics of the used end device. However, such a personalization increases the applications complexity since every individual alternatives have to be considered and implemented. To provide substantial support for the development of personalized (mobile) multimedia applications, we developed a domain independent software framework for an efficient and cost-effective development of personalized mobile multimedia applications. We illustrate the framework in the specific domain of personalized mobile tourist information.

Canonical processes for creating personalized semantically rich multimedia presentations

Authoring of multimedia content can be considered as composing media assets such as images, videos, text, and audio in time, space, and interaction into a coherent multimedia presentation. Personalization of such content means that it reflects the users’ or user groups’ profile information and context information. Enriching the multimedia content with semantically rich metadata allows for a better search and retrieval of the content. To actually create personalized semantically-rich multimedia content, a manual authoring of the many different documents for all the different users’ and user groups’ needs is not feasible. Rather a (semi-)automatic authoring of the content seems reasonable. We have analyzed in detail today’s approaches and systems for authoring, personalizing, and semantically enriching multimedia presentations. Based on this analysis, we derived a general creation chain for the (semi-)automatic generation of such content. In this paper, we introduce this creation chain. We present our software engineering support for the chain, the component framework SemanticMM4U. The canonical processes supported by the creation chain and SemanticMM4U framework are described in detail. We also provide an explicit mapping of SemanticMM4U framework components to the processes and argue for the benefits of defining canonical processes for creating personalized semantically rich multimedia presentations.

Context-driven smart authoring of multimedia content with xSMART

In recent years, many highly sophisticated multimedia authoring tools have been developed. Up to today, these systems integration of the targeted user context, however, is limited. With our Context-aware Smart Multimedia Authoring Tool (xSMART) we developed a semi-automatic authoring tool that integrates the targeted user context into the different authoring steps and exploits this context to guide the author through the content authoring process. The design of xSMART allows that it can be extended and customized to the requirements of a specific domain by domain-specific wizards. These wizards realize the user interface that meets best the domain-specific requirements and effectively supports the domain experts in creating their content targeted at a specific user context.