Publikationen Institute und Zentren - FH Graubünden

Abstract: The identification and labeling of non-hierarchical relations are among the most challenging tasks in ontology learning. This paper describes an approach for suggesting ontology relationship types to domain experts based on implicitly learned relations from a domain corpus. The learning process extracts verb- vectors from sentences containing domain concepts. It computes centroids for known relationship types and stores them in the knowledge base. Vectors of unknown relationships are compared to the stored centroids using the cosine similarity metric. The system then suggests the relationship type of the most similar centroid. Domain experts evaluate these suggestions to refine the knowledge base and constantly improve the component's accuracy. Using four sample ontologies on "energy sources", this paper demonstrates how link type suggestion aids the ontology design process. It also provides a statistical analysis on the accuracy and average ranking performance of batch learning versus online learning.

DOI: https://doi.org/10.1007/978-3-540-76888-3_12 

Abstract: Ontology evolution is an intrinsic phenomenon of any knowledge-intensive system, which can be addressed either implicitly or explicitly. This paper describes an explicit, data-driven approach to capture and visualize ontology evolution by semi-automatically extending small seed ontologies. This process captures ontology changes reflected in large document collections. The visualization of these changes helps characterize the evolution process, and distinguish core, extended and peripheral relations between concepts.

Abstract: Analyzing the check-in information of open source software projects which use a version control system such as CVS or SUBVERSION can yield interesting and important insights into the programming behavior of developers. As in every major project tasks are assigned to many developers, the development must be coordinated between these programmers. This paper describes three visualization techniques that help to examine how programmers work together, e.g. if they work as a team or if they develop their part of the software separate from each other. Furthermore, phases of stagnation in the lifetime of a project can be uncovered and thus, possible problems are revealed. To demonstrate the usefulness of these visualization techniques we performed case studies on two open source projects. In these studies interesting patterns of developers' behavior, e.g. the specialization on a certain module can be observed. Moreover, modules that have been changed by many developers can be identified as well as such ones that have been altered by only one programmer.

Abstract: Mobile technology becomes an increasingly important issue for tourists as well as tour operators. A proof for the importance of location based services and mobile applications in tourism are a recognisable number of studies which were conducted during the past years and funded by the European Union. Interestingly enough, there was no breakthrough of location based mobile applications in tourism from a user perspective up to date. This paper raises the question if evaluation procedures and methods of location based mobile devices fit the user perspective in tourism. An analysis of past projects is used to find the gaps in evaluation methods and results in learning for future projects of this kind.

Abstract: This paper is about valuating direct intercontinental flights as opposed to non-direct ones, taking an individual travelers' perspective. The methodology of this study is derived from a hedonic approach which tries to explain actual expenditures (in our case of air transport) by means of a number of non-divisible characteristics (origin and destination, number of stopovers, choice of travel class). The results reveal that direct flights are valued higher than non-direct ones. However, the share of this advantage in relation to other characteristics by which a flight can be valued is limited, ranging from 15 to 20 per cent (in the context of travel in economy class; ceteris paribus) to less than 10 per cent (in the context of travel in business class; ceteris paribus). In contrast, and to put those numbers into perspective, choosing business class (instead of economy) adds 240% to an economy air fare (ceteris paribus).

Abstract: This paper is about the importance of purchasing criteria in intercontinental air transport as exemplified by origin and destination between Switzerland and selected destinations in the Far East. Passengers waiting to board their flights from Switzerland to Far Eastern destinations were invited to participate in a choice experiment. Subsequently, they were offered choice sets where they had to choose among two different flight tickets from Zurich to one specific destination within each set. To statistically analyse the data a variance decomposition method was performed to learn about the importance of the different purchasing criteria. The results show that for both the business and economy class passengers alike and the business and leisure travellers the most important criteria is the price, even before the direct connection, which is the second most important criteria. In comparison with transatlantic travellers, the Far East travellers value the direct flight more and the price is a somewhat less important.

DOI: https://doi.org/10.1117/12.643272 

Abstract: This paper deals with the visual representation of a particular kind of structured data: trees where each node is associated with an object (leaf node) of a taxonomy. We introduce a new visualization technique that we call Trees In A Treemap. In this visualization edges can either be drawn as straight or orthogonal edges. We compare our technique with several known techniques. To demonstrate the usability of our visualization techniques, we apply them to find interesting patterns in decision trees and network routing data.

DOI: https://doi.org/10.1007/11752660_15 

Abstract: In this work we present the basic concepts for a dynamic plug-in-based software architecture using concepts from the Petri net-based MAS framework Mulan. By transferring the concepts of agent-orientation to a plug-in-based architecture we are able to design our application and the plug-in-based system on an abstract level. Moreover, general problems that evolve from a highly dynamic and configurable architecture have been solved by basing the conceptual design on multi-agent principles. In this paper we discuss the general properties of extensible systems and the benefits that can be achieved when applying the multi-agent view to their architecture. In addition to the conceptual modeling of such architectures, we provide a practical example where the concept has been successfully applied in the development of the latest release of Renew. Through the introduction of the multi-agent concepts, the new architecture is now – at runtime – dynamically extensible by registering plug-ins with the management system.

DOI: https://doi.org/10.1007/11872283_2 

Abstract: Process mining and multi-agent models are powerful techniques for the analysis of processes and organizations. However, the integration of both fields has seldom been considered due to the lack of common conceptual background. We propose to close this gap by using Petri nets as an operational semantics and consider process mining a useful addition to monitor and debug multi-agent systems in the development phase. Mining results can be represented in the formalized form of Petri nets that allows to validate or verify the actual behavior. On our way to mining complex interactions within (simulated) organizations, we present a plug-in extension of our Petri nets-based agent platform Mulan/Capa for recording interaction logs. Using process mining, the logs can be mapped by some intermediate steps to agent protocols e.g. represented as AgentUML interaction protocol diagrams. These diagrams are a descriptive representation form that combines organizational and control flow information. Furthermore, they can be mapped to executable Petri nets, thus allowing to feed mining results back into the design phase.

Abstract: Flexibility has received much attention, but an important question has not been answered: How can a company properly derive the needed flexibility based on environmental uncertainties? The contingency theory states that there has to be a fit between a company's structure and its environment. This leads directly to the conclusion that in uncertain and unknown or quickly changing conditions a company should be more flexible than in stable environments to cope with these changes. Traditional structures in manufacturing companies, such as derived from mass production, are no longer sufficient to ensure success in today's business landscape. The future of manufacturing companies seems to lie in more flexibility. Flexibility is a multi-dimensional concept and every company seems to have a different understanding of it. To cope with these different understandings, we have developed a conceptual framework to derive the needed degree of flexibility from the environmental context and to break it down into different forms of flexibility. Based on this framework, a balanced scorecard will be developed for the controlling of changes in flexibility. The use of the framework will be demonstrated by means of seven case studies from European manufacturing companies.