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Dive into the research topics where Ralf Dörner is active.

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Featured researches published by Ralf Dörner.


international symposium on mixed and augmented reality | 2004

Accuracy in optical tracking with fiducial markers: an accuracy function for ARToolKit

Daniel F. Abawi; Joachim Bienwald; Ralf Dörner

Optical tracking with fiducial markers is commonly used in augmented reality (AR) systems - AR systems that rely on the ARToolKit (Kato and Billinghurst, 1999) are prominent examples. The information obtained by the tracking subsystem are widely used in AR, e.g. in order to calculate how virtual objects should be located and oriented. The results of extensive accuracy experiments with single markers are reported and made operational by the definition of an accuracy function. The results show a specific distribution of tracking accuracy dependent on distance as well as angle between camera and marker. This insight is applicable for designing the set-up of AR applications in general that rely on optical tracking.


IWEC | 2003

Authoring Mixed Reality — A Component and Framework-Based Approach

Ralf Dörner; Christian Geiger; Michael Haller; Volker Paelke

This paper describes the basic ideas of our effort to develop a framework for the structured authoring of mixed reality (MR) applications. The overall objective of the AMIRE project is to define and implement a software system that allows content experts to easily design and implement mixed reality applications without detailed knowledge about the underlying base technologies. This requires a user centred approach for authoring in contrast to existing approaches that are primarily driven by technological features and problems of MR systems. In order to support content experts in MR design, the AMIRE framework also consist of a visual authoring tool that uses a component oriented base technology for building mixed realities. The application of reusable building blocks at different levels of granularity (MR gems, MR components) is the central idea in this project.


Computers & Graphics | 2002

Synergies between interactive training simulations and digital storytelling: a component-based framework

Ralf Dörner; Paul Grimm; Daniel F. Abawi

Abstract A vital requirement for a successful software framework for digital storytelling is that it takes the abilities and background of the story authors into account. Dedicated tools should support authors in expressing their stories within this framework at an adequate level and point out an according authoring process for digital stories. The software framework should provide communication interfaces between technology experts, storytelling experts and application domain-experts. These requirements are similar to the ones already encountered when setting up a framework for interactive training applications. We present a concept how component and framework methodologies from software engineering as well as concepts from artificial intelligence can foster the design of such a software framework. The software architecture of our proposed framework is discussed as well as the according authoring process and tools. An implementation of our concept is described and lessons learned during using this framework in the application domain of emergency training are addressed. Although the framework has been applied for training purposes in particular, it can be used as a basis for a digital storytelling framework in general.


Information Systems | 2010

Interactive visualization for opportunistic exploration of large document collections

Simon Lehmann; Ulrich Schwanecke; Ralf Dörner

Finding relevant information in a large and comprehensive collection of cross-referenced documents like Wikipedia usually requires a quite accurate idea where to look for the pieces of data being sought. A user might not yet have enough domain-specific knowledge to form a precise search query to get the desired result on the first try. Another problem arises from the usually highly cross-referenced structure of such document collections. When researching a subject, users usually follow some references to get additional information not covered by a single document. With each document, more opportunities to navigate are added and the structure and relations of the visited documents gets harder to understand. This paper describes the interactive visualization Wivi which enables users to intuitively navigate Wikipedia by visualizing the structure of visited articles and emphasizing relevant other topics. Combining this visualization with a view of the current article results in a custom browser specially adapted for exploring large information networks. By visualizing the potential paths that could be taken, users are invited to read up on subjects relevant to the current point of focus and thus opportunistically finding relevant information. Results from a user study indicate that this visual navigation can be easily used and understood. A majority of the participants of the study stated that this method of exploration supports them finding information in Wikipedia.


virtual reality modeling language symposium | 2000

Three-dimensional Beans—creating Web content using 3D components in a 3D authoring environment

Ralf Dörner; Paul Grimm

This paper deals with the question how the component idea can be transferred to the authoring of 3D content for the WWW. The concept of 3D Beans and their according authoring environment is presented. In addition, an implementation of this concept using Java3D and Java Beans is described. Advantages of the concept are discussed and illustrated with an application example from the area of computer-based training. Major advantages of the 3D Beans concept are on the one hand that 3D content can be created in a virtual environment more directly and efficiently using pre-fabricated components that fit together. Especially, as the author is supported by a Bean authoring environment that itself uses information from the 3D Beans. On the other hand, a 3D authoring environment offers more degrees of freedom for authoring component-based applications. /0


computational intelligence | 1999

Temporal hypermedia for multimedia applications in the World Wide Web

Norbert Braun; Ralf Dörner

Multimedia applications within the World Wide Web (WWW) have to deal with difficulties like executing within Web pages and being transferred via the Internet. However, the temporal aspects of hypermedia features for continuous media like audio and video resemble all other kinds of multimedia applications. These temporal aspects are discussed in consideration of presentation and authoring facilities. A system architecture and implementation relying on commercial WWW technology is presented.


Lecture Notes in Computer Science | 2004

A toolkit for authoring non-linear storytelling environments using Mixed Reality

Daniel F. Abawi; Silvan Reinhold; Ralf Dörner

Efficient creation of high-quality Mixed Reality (MR) content is challenging today due to a variety of difficult problems not only on a technological level. As a consequence, authoring problems prevent a more widespread usage of MR in digital storytelling. We present a novel authoring toolkit that allows an efficient integration of MR technology in various interactive non-linear storytelling applications. We demonstrate its usage in an example use case that represents typical MR-related authoring tasks like the calibration of real and virtual objects or the specification of their semantic relationship. As a peculiarity, a seamless provision of the MR authoring toolkit together with the storytelling application is conceptually and technically supported. Thus, we show how authors, even without technical background, who want to create MR-enriched storytelling experiences, can be adequately supported. The underlying concepts for an efficient implementation of our proposed authoring toolkit are briefly described.


International Journal of Human-computer Studies \/ International Journal of Man-machine Studies | 2011

Using a game controller for relaying deictic gestures in computer-mediated communication

Swen Walkowski; Ralf Dörner; Mirja Lievonen; Duska Rosenberg

In computer-mediated communication, participants often experience a loss of information that would have been conveyed by non-verbal means in a face-to-face communication. They need to compensate for this loss by being more verbose which may have a negative impact on the efficiency of communication or give rise to misunderstandings. In this paper, we present a computer system that augments the imagery perceived from the remote site with additional visual information and that can be controlled by using a Nintendo Wiimote game controller. Our prototype illustrates our approach how a system might be able to partially compensate for the information typically lost in conventional video conferencing where deictic gestures cannot be relayed properly to the remote site. Concerning user acceptance, our user tests also show that the visualization technique is crucial which is used for highlighting the objects or persons that are being pointed at. Adequate visualization techniques based on non-photorealistic rendering are proposed.


computer graphics international | 1998

Performing 3D scene and animation authoring tasks efficiently: an innovative approach

Colette Elcacho; Arno Schäfer; Ralf Dörner; Volker Luckas

3D animation is becoming a key technology in application areas such as information visualization, telecommunications or teaching and training systems. In addition, the application potential of 3D animation is growing due to innovations like VRML. The authoring of 3D scenes and animations is, therefore, increasingly becoming a task in areas other than its classical application areas, entertainment and marketing, and is not only performed by professional computer animators. Accordingly, there is a rising demand for authoring tools that are efficient and easy to use, cost-effective, flexible and suitable for distributed systems. In this paper a concept for authoring 3D animations that can fulfil these requirements is presented. Based upon an element-oriented approach similar to clip art in drawing, authoring efficiency is increased. The concept is described and its implementation and applications are briefly discussed.


Informatik Spektrum | 2016

Virtual Reality und Augmented Reality (VR/AR)

Ralf Dörner; Wolfgang Broll; Paul Grimm; Bernhard Jung

Preise, Perspektiven, Potenziale Unter 300 € soll sie kosten. Ende 2014 soll sie als Produkt erscheinen. Die Oculus Rift, eine Brille, die ihre Träger in eine Virtuelle Realität (VR) versetzen kann. Bisherige VR-Brillen kosten oft mehr als das Zehnfache und vermitteln aufgrund eines eingeschränkteren Sichtfelds keinen derart guten Eindruck einer virtuellen 3D Welt. Bessere Hardware für einen Bruchteil des Preises? Kein Einzelfall. Ein neues Anwendungsfeld macht es möglich: Entertainment. Statt wie bisherige VR Hardware eine kleine Zielgruppe z. B. für industrielle Anwendungen zu adressieren, zielen neue Geräte auf den Computerspielemarkt, einen Massenmarkt. Nach einer vom Bundesverband Interaktive Unterhaltungssoftware in Auftrag gegebene Studie der GfK wird das Marktvolumen allein in Deutschland mit 1,82 Milliarden Euro beziffert. Die Firma Oculus VR brauchte vor dem Hintergrund derartiger Marktperspektiven nur vier Stunden, um über Crowdfunding mittels der Online-Plattform Kickstarter 250.000 US

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Paul Grimm

Fulda University of Applied Sciences

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Johannes Luderschmidt

RheinMain University of Applied Sciences

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Simon Lehmann

RheinMain University of Applied Sciences

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Daniel F. Abawi

Goethe University Frankfurt

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Ulrich Schwanecke

RheinMain University of Applied Sciences

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Nadia Haubner

RheinMain University of Applied Sciences

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Christian Geiger

University of Applied Sciences Düsseldorf

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Stefan Göbel

Technische Universität Darmstadt

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Jörg Schweitzer

RheinMain University of Applied Sciences

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