Roer, Peter (Ed.) et al.: Mobilkommunikation : Technologien und Anwendungen. Berlin, Offenbach: VDE-Verlag GmbH, 2012. (Informationstechnische Gesellschaft (ITG) 234), pp. 122-127

For convenience more and more communication is shifted to wireless networks and enterprise communication follows this general trend. With that the requirements have changed considering mobile applications and end devices. Even that the mobile devices get more resources e.g. performance (CPU), graphic power (GPU) and capacity (RAM, hard disk size), new mobile applications require more advanced resources. These new applications benefit from the cloud approach and introduce the client/server concept onto mobile devices. In this paper we will analyse today's enterprise Wireless LAN implementations to support these new mobile applications. These upcoming applications require high processing power and a reliable network infrastructure as most of the data will be transferred between the mobile device and the cloud infrastructure. Furthermore we will analyse the capabilities in regard to QoS to identify if these QoS mechanisms can help to improve network performance and allow these new applications to work. These new applications require cloud computing where the demand on high bandwidth and low latency has to be fulfilled. Therefore investigating today's standard on wireless communication in enterprises is highly important and the key question will be if those applications are supported in existing Wireless LAN implementations. This analysis will be shown in the form of a practical experiment where key requirements on mobile communication in enterprise environments are identified. Furthermore restrictions will be shown that limit these applications to function properly. These restrictions are a starting point to enhance or redesign wireless network infrastructures in enterprise environments.

Augmented Reality (AR) ist eine eng mit der Virtuellen Realität (VR) verwandte Technologie. Der Anwender taucht dabei nicht komplett in eine virtuelle, computergenerierte Umgebung ein, sondern verbleibt in seiner realen Umgebung, die mit virtuellen Objekten erweitert wird. Diese virtuellen Objekte werden dabei möglichst passgenau in das Blickfeld des Anwenders eingeblendet. Wichtige klassische Forschungsthemen im Bereich der AR sind das sogenannte Tracking, d.h. die Bestimmung der Blickrichtung des Anwenders, die korrekte Beleuchtung der virtuellen Objekte, sowie Schattenwurf und Verdeckung zwischen realen und virtuellen Objekten. Ein Thema, das in den vergangenen Jahren immer stärker in den Vordergrund gerückt ist, ist die Frage nach der Systemarchitektur von AR-Systemen. Mit dieser Fragestellung befaßt sich die vorliegende Arbeit. Zunächst werden existierende VR- und AR-Systemarchitekturen analysiert. Ausgehend vom existierenden VR-Standard VRML bzw. seinem Nachfolger X3D wird dann untersucht, um welche Bestandteile dieser Standard erweitert werden muß, um auch für mobile AR-Anwendungen genutzt werden zu können. Dabei liegt der Fokus auf dem Gerätemanagement, der Kommunikation im Netzwerk und der Entwicklung und dem Debugging mobiler AR-Anwendungen.

IEEE Computer Society: IEEE Virtual Reality 2007. VR Tutorial and Workshop Proceedings [CD-ROM] : IEEE Symposium on 3D User Interfaces. Piscataway, NJ: IEEE Service Center, 2007, 5 p.

The semantics of the X3D ISO standard describe an abstract functional behavior of time-based, interactive 3D, multimedia information. It is independent of any specific software or hardware setup. However, X3D clients and applications today are mainly built for desktop systems running a web-browser. During the last years we have build a VR environment which utilizes the VRML- and X3DISO standards as a basis for an application programming and description language. In this paper we discuss some of our results and experiences. We present necessary extensions to the ISO standard, e.g. to support different interaction and navigation tasks, and discuss how existing parts can be interpreted differently in a VR environment.

ACM SIGGRAPH: Proceedings WEB3D 2007 : 12th International Conference on 3D Web Technology. New York: ACM Press, 2007, pp. 27-36

In this paper, we explore and discuss X3D as an application description language for advanced mixed reality environments. X3D has been established as an important platform for today's web-based visualization and VR applications. Yet, there are very few examples for augmented reality systems utilizing X3D beyond a simple geometric description format. In order to fulfill the image compositing and synthesis requests of today's augmented reality applications, we propose extensions to X3D, especially with a focus on lighting and realistic rendering.

Journal of Virtual Reality and Broadcasting, (2006), 3, 13 p.

In this paper the software architecture of a framework which simplifies the development of applications in the area of Virtual and Augmented Reality is presented. It is based on VRML/X3D to enable rendering of audio-visual information. We extended our VRML rendering system by a device management system that is based on the concept of a data-flow graph. The aim of the system is to create Mixed Reality (MR) applications simply by plugging together small prefabricated software components, instead of compiling monolithic C++ applications. The flexibility and the advantages of the presented framework are explained on the basis of an exemplary implementation of a classic Augmented Reality application and its extension to a collaborative remote expert scenario.

Braz, José (Ed.) et al.: GRAPP 2006. Proceedings : Proceedings of the First International Conference on Computer Graphics Theory and Appilications. Setúbal: INSTICC Press, 2006, pp. 200-207

In this paper the software architecture of a framework which simplifies the development of applications in the area of Virtual and Augmented Reality is presented. It is based on VRML/X3D to enable rendering of audio-visual information. We extended our VRML rendering system by a device management system that is based on the concept of a data-flow graph. The aim of the system is to create Mixed Reality (MR) applications simply by plugging together small prefabricated software components, instead of compiling monolithic C++ applications. The flexibility and the advantages of the presented framework are explained on the basis of an exemplary implementation of a classic Augmented Reality application and its extension to a collaborative remote expert scenario.

Schenk, Michael (Ed.): 8. IFF-Wissenschaftstage 2005. Tagungsband : Virtual Reality and Augmented Reality zum Planen, Testen und Betreiben technischer Systeme. Magdeburg: Fraunhofer IFF, 2005, pp. 121-130

HCI International 2005. [Proceedings CD-ROM]. Mahwah, New Jersey: Lawrence Erlbaum Associates, Inc., 2005, 10 p.

All modern VR and AR toolkits provide some kind of sensor abstraction for different types of input and output devices and user interaction. Almost all systems today define a single layer of abstraction. Most toolkits usually support only low level data streams leaving most of the user interface implementation work to the IT professional. Some provide only high level interaction responder (e.g. X3D) without the possibility to access low level I/O information and streams. No toolkit supports adoption of UI elements to the environment the user is working in, e.g. immersive or desktop. In our approach we build three level of abstraction for user interaction which leads to a more flexible and scalable result. Application programmers are free to use low level streams (e.g. tracker data) directly, high level responder (e.g. the user `touched' something) and even application requests (e.g. the systems needs a float input or a list of selected objects) which are automatically mapped to 2D UI elements or immersive responder, depending on the environment and used devices. Two examples illustrate the flexibility and efficiency of our approach.

Skala, Vaclav (Ed.): WSCG 2005 [CD-ROM] : Full Papers, Short Papers, Posters, Journal of WSCG. Plzen: University of West Bohemia, 2005, 4 p.

In this paper the concept and design of a software framework which provides a transparent data flow for interactive Mixed Reality (MR) applications is discussed. The design was affected by our demands on platform independency, simplicity, network transparency, maximum performance and availability of runtime debugging facilities. Our software framework tries to simplify the development of MR applications by using the concept of a data flow graph. The developer builds such a graph from a library of small software components that communicate via the edges of the graph.

HCI International 2005. [Proceedings CD-ROM]. Mahwah, New Jersey: Lawrence Erlbaum Associates, Inc., 2005

This paper describes a Mixed Reality-supported interactive museum exhibit. Using an easy and intuitive pointing gesture recognition system, the museum visitor is able to create his/her own exhibit choosing between different artists or between different images and explore them in real-time. The usage of a video-based gesture tracking system ensures seamless integration of Mixed Reality technologies into a traditional museum's environment. Furthermore, it addresses even technically unversed users since no additional physical devices are needed and even no training phase is necessary for the interaction.

Mudge, Mark (Ed.) et al.: VAST 2005. Proceedings : The 6th International Symposium on Virtual Reality, Archaeology and Intelligent Cultural Heritage. Aire-la-Ville: Eurographics Association, 2005, pp.113-119

This paper describes a Mixed Reality-supported interaction system to explore digitized artworks like twodimensional paintings and three-dimensional sculptures. Using an easy and intuitive pointing gesture recognition system, the user is able to interact directly with the artworks, which leads to a deeper involvement with and understanding of the art pieces. The usage of a video-based gesture tracking system ensures seamless integration of Mixed Reality technologies into a traditional museum's environment. Furthermore, it addresses even technically unversed users since no additional physical devices are needed and even no training phase is necessary for the interaction.

Spencer, Stephen N. (Ed.): Web3D 2004. Proceedings : Ninth International Conference on 3D Web Technology. New York: ACM, 2004, pp. 71-78, 182

Conceptually, the semantics of X3D describe an abstract functional behaviour of time-based, interactive 3D, multimedia information and do not all specify a specific software or hardware setup. However X3D clients and applications today are mainly built for desktop systems running a web browser. In this papr we explore how suitable X3D and W3C technologies can be utilized as an application and programming model for immersive virtual environments. We present a system implementation, necessary extensions to the X3D specification and discuss how standard nodes can be interpreted differently in an immersive setting.

Thema Forschung, (2003), 1, pp. 66-73

Müller, Stefan (Ed.) et al.: IEEE and ACM International Symposium on Mixed and Augmented Reality 2002. Proceedings.. Los Alamitos, Calif.: IEEE Computer Society, 2002, pp. 263-264

We present the system architecture of a mobile outdoor augmented reality system for the Archeoguide project. We begin with a short introduction to the project. Then we pre-sent the hardware we chose for the mobile system and we describe the system architecture we designed for the soft-ware implementation. We conclude this paper with the first results obtained from experiments we made during our trials at ancient Olympia in Greece.

Stanke, Gerd (Ed.) et al.: EVA 2002. Proceedings : Elektronische Bildverarbeitung & Kunst, Kultur, Historie 2002. Berlin: Gesellschaft zur Förderung angewandter Informatik e.V., 2002, pp. 33-40

ARCHEOGUIDE (Augmented Reality-based Cultural Heritage On-site GUIDE) is the acronym of a project, funded by the EU IST framework (IST-1999-11306), and pursued by a consortium of European organizations. The system allows the user/visitor to experience a Virtual Reality world featuring computer-generated 3D reconstructions of ruined sites without isolating him from the "real world". The key feature of the system is the position and orientation tracking technique used in determining the user's viewpoint. This is an image registration technique based on phase correlation. This paper presents the technique in detail and gives practical examples of the application of the technique in the ARCHEOGUIDE system. In particular, it describes how calibrated reference images may be matched to live video by image transformation to the Fourier domain and phase calculation for translation, rotation, and scaling operations.

Figueiredo, Antonio Dias de (Ed.) et al.: Proceedings of 3ª Conferência da Associação Portuguesa de Sistemas de Informação 2002. CD-ROM. Coimbra, 2002

The current state of information and communication technologies, pointing out the massive use of computer graphics, is instigating new possibilities for data visualization and analysis. Large amounts of data can be represented in an effective way of understanding by the adoption of an appropriate visualization technique. In the present work, we are investigating the use of novel interaction technologies for the visualization of financial data, concretely stock market information. We are using a 3D immersive environment, in which the user is able to interact in a non-obtrusive form, being able to perceive information in several dimensions, as well as to perform interactions in a multi-modal way.

IEEE Computer Graphics and Applications, Vol.22 (2002), 5, pp. 52-60

Archeoguide offers personalized augmented reality tours of archaeological sites. It uses outdoor tracking, mobile computing, 3D visualization, and augmented reality techniques to enhance information presentation, reconstruct ruined sites, and simulate ancient life.

Institute of Electrical and Electronics Engineers (IEEE): 3D Data Processing Visualization and Transmission, 2002. Proceedings. Los Alamitos, Calif.: IEEE Computer Society, 2002, pp. 337-345

This paper describes the work performed for the ARCHEOGUIDE (Augmented Reality-based Cultural Heritage On-site GUIDE) project. ARCHEOGUIDE is funded by the EU IST framework (IST-1999-11306), and pursued by a consortium of European organizations. It delivers an interactive, personalized, augmented reality (AR) guide for the visualization of ruined archaeological sites. It is based on mobile real-time computing, networking, and 3D visualization. Its users are presented with monument reconstructions, navigation aid and historical information in a user-friendly way through the use of multi-modal interaction techniques. The key features of the system are a novel hybrid position and orientation tracking technique used in determining the user's viewpoint, navigation aid, outdoor operation, and real-time 3D visualization of monuments, artifacts, and life. This paper presents examples of the system's use at the archaeological site of Ancient Olympia in Greece.

ACM SIGGRAPH: VAST 2001: Proceedings of the International Symposium on Virtual Reality, Achaeology and Cultural Heritage. Glyfada, 2001, pp. 161-168

This paper presents the design and implementation issuesassociated with the development of a mobile device for theARCHEOGUIDE project. We describe general and applicationspecific design goals as well as the technical requirements theimplementation is based upon. Since speed is crucial for aninteractive application we provide a survey of mobile andwearable computing equipment especially consideringperformance aspects. A detailed overview of available hardwarecomponents follows. We describe the decisions made duringprototype development and present the final result

Giagourta, Venetia (Ed.) et al.: International Conference on Augmented, Virtual Environments and Three-Dimensional Imaging. Proceedings 2001, pp. 1-5

In ARCHEOGUIDE (Augmented Reality based Cultural Heritage On-site GUIDE) is the acronym of a project pursued by a consortium of European organizations: Intracom S.A. (Greece), Fraunhofer Institute of Computer Graphics (IGD) (Germany), the Computer Graphics Center (ZGDV) (Germany), the Centro de Computacao Gráfica (CCG) (Portugal), A&C 2000 Srl (Italy), Post RealityS.A. (Greece) and the Hellenic Ministryof Culture (Greece). Funded by the EU IST framework (IST-1999-11306), the consortium is developing a system that will fundamentally change the way visitors view and learn about a cultural heritage site. In particular, we are designing and developing an Augmented Reality system that will allow the visitors to see computer-generated reconstruction of the site without cutting them off from the real surroundings of the site. As a first trial site, we have selected ancient Olympia in Greece, the famous birthplace of the Olympic games.

Skala, Vaclav: WSCG 2000. Conference Proceedings Vol. 2. Plzen: University of West Bohemia, 2000, pp. 402-409

We present an algorithm for the real-time simulation of virtual cables using inverse kinematics. A cable is modeled by consecutive cylinder segments of equal size. The segments are connected by ball joints. At every joint there is a spiral spring acting against the excursion of the joint. Given a start and an end position of the cable, the algorithm calculates the shape of the cable that leads to minimal total energy. The total energy is the sum of the potential energies of the segments and the elastic energies of the springs. First, the algorithm calculates a cable with minimal total energy consisting of two segments. This is taken as a starting basis for the computation of a cable consisting of four segments. At each following step, the number of segments is doubled and a new shape of the cable is calculated based on the solution of the previous step. The great advantage of this approach is the easy accommodation of the solution exactness to the available computation time. If the user of the VR application is moving the cable, he/she gets a fast but rough feedbaIf. If he/she stops moving it, he/she gets an exact shape.