1. Asa MacWilliams Lehrstuhl für Angewandte Softwaretechnik Institut für Informatik Technische Universität München Asa@MacWilliams.de June 27, 2005 A Decentralized Adaptive Architecture for Ubiquitous Augmented Reality Systems Dissertation

2. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 2/12 Summary Ubiquitous augmented reality: convergence of augmented reality and ubiquitous computing I address software engineering challenges with: –Adaptive service dependency architecture –Distributed middleware –Design at run time Approach: –Constructive: problem analysis, existing approaches –Explorative: show feasibility in DWARF and its systems

3. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 3/12 Ubiquitous Augmented Reality (UAR) Extension of augmented reality interaction into ubiquitous computing environments

4. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 4/12 Developing Software for UAR Basic technology available; many application areas: Collaborative design Navigation Construction and Maintenance...and more –Health care, –Campus, –Rescue team… However, few real systems built to date One reason: software development challenges

5. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 5/12 UAR Software Development Challenges Ill-defined requirements Component uncertainty Performance constraints addresses depends on Middleware infrastructure Middleware infrastructure Proposed Solution depends on Software architecture Software architecture Development process Development process New technology Many people, many disciplines Users in the field Mobile users Limited sensor & network range Low latency for immersive AR Scalability for ubiquitous computing

6. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 6/12 Related Work Augmented Reality and Ubiquitous Computing projects –Studierstube, Tinmith, Coterie, ARVIKA, ImageTclAR, Aura, Ninja, Gaia, Context Toolkit, Fluidum, UbiCom, … (many more) –Interesting approaches: data flow architectures, latency layering, reflection, service discovery, prototyping Current software engineering techniques –Distributed component architectures: CORBA Component Model, Web Services –Agile development methods: Extreme Programming, Scrum DWARF (Distributed Wearable Augmented Reality Framework) research project at TUM –DWARF 2001: No development process, limited adaptivity, limited interaction, used for only one system

7. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 7/12 Proposed Solution Approaches: Data flow architecture Service discovery Approaches: Reflection Latency layering Approaches: Agile development Prototyping

8. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 8/12 Wearable computer Stationary computer Adaptive Service Dependency Architecture New architectural style: Loosely coupled distributed services Parameterized dependencies between services Dependencies change based on context Middleware maintains adaptive graph of services Used to build frameworks manages Service Manager manages communi- cates Service Marker Description Video Grabber Optical Tracker Scene Description Viewer AbilityNeed Dependency Type=PoseData source=AR lab target=head

9. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 9/12 Decentralized Middleware Distributed middleware maintains adaptive system Middleware’s tasks can be decomposed: –Manage a single service –Set up communication between two services –Adapt a service to its context –Manage adaptive service graph Decentralized implementation possible –e.g. using CORBA and SLP in DWARF Based on externalized service descriptions Optical Tracker Viewer Optical Tracker Video Grabber Optical Tracker Marker Description C Marker Description B Marker Description A Viewer Inference 3 Inference 2 Tracker 1 Tracker 2 Tracker 3 Viewer Inference 3 Inference 2 Tracker 1 Tracker 2 Tracker 3 ViewerInference Inference 2 Inference 1 Tracker 1 Tracker 2 Tracker 3 Inference Tracker 1 ViewerTracker 2 Tracker 3

10. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 10/12 Process: Design at Run Time Continuous, incremental development process Users provide synchronous and asynchronous feedback Developers improve running system Synchronous: Jam Sessions Asynchronous: Continuous Extension Supported by architecture Supported by tools

11. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 11/12 Results Several UAR systems were built using implementation of architecture, middleware and process within DWARF – and they worked. –Component uncertainty well addressed by architecture –Ill-defined requirements addressed by process –Middleware performance (latency, scalability, resource use) are adequate Feedback from users on systems: –Well understood; good for prototyping –Industrial partners: adaptivity of limited real-world use Feedback from developers on framework: –Complexity and manageability concerns –“Larger system than we could have built with X”

12. June 27, 2005 Decentralized Adaptive Archicture for UAR Systems Asa MacWilliams 12/12 Conclusion The software engineering challenges of UAR can be addressed with the Adaptive Service Dependency Architecture, its Middleware and Design At Run Time But: –Only been shown for prototypes –Middleware and tools in DWARF are not of industrial quality (manageability and scalability limitations) –Model does not handle stateful services well –Development process is mostly conceptual –Experimental infrastructure for experimental systems… dangerous Future work: empirical validation –“Harden” framework and middleware implementation –Build UAR systems for real-world use (commercial, industrial)

13. Asa MacWilliams Lehrstuhl für Angewandte Softwaretechnik Institut für Informatik Technische Universität München Asa@MacWilliams.de June 27, 2005 A Decentralized Adaptive Architecture for Ubiquitous Augmented Reality Systems Dissertation Thank you… for your attention - and for your support. Any questions? Asa@MacWilliams.de