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VisualBeans: from Desktop to PDA

VisualBeans: from Desktop to PDA. Dr. Tom Fitzpatrick, Lancaster University tf@comp.lancs.ac.uk Distributed Multimedia Research Group Lancaster University

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VisualBeans: from Desktop to PDA

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  1. VisualBeans:from Desktop to PDA Dr. Tom Fitzpatrick, Lancaster Universitytf@comp.lancs.ac.uk Distributed Multimedia Research GroupLancaster University Information Technology Department &Advanced Communications UnitRutherford Appleton LaboratoryDistributed Systems Research GroupSchool of Computing and Mathematical SciencesOxford Brookes University

  2. Distributed Cooperative Visualization • Visualization growing in importance • scientific visualization • engineering visualization • general information visualization • Distributed Cooperative Visualization • multiple participants distributed over network • e.g. expert scientists from various sites • collaborate using distributed visualization tools • also collaboration tools such as whiteboards, A/V comms etc • may share control over visualization parameters • e.g. zoom, rotate, pan, contouring/colourmapping etc • enabled by research into CSCW and distributed computing

  3. Modular Visualization Environments (MVEs)

  4. MANICORAL • Enhance desktop environment of collaborating scientists • Constructed desktop cooperative work environment to allow collaboration between geographically distributed geoscientists • Cooperative visualization and display of datasets • shared control of selected parameters • Audio/video conferencing tools & shared whiteboard facilities • Experiences • Heterogeneity a major issue • differences in capabilities/power between users’ workstations • Heavy reliance on audio communications • convey state of each participant amongst each other • state of rendering progress • difficulties due to ‘outboard’ nature of audio support • Resource management important • disastrous CPU battling between visualization and audio comms • network conditions

  5. Middleware Support for Adaptation • The Adapt Project: middleware for adaptive applications • Subject to wide-ranging connectivity: LAN, Wireless LAN • For most multimedia apps to remain operational, they must adapt • reduce quality of media streams, drop/combine streams • change the “big picture” • and the reverse if upgrading to better connectivity! • The TOAST middleware platform • Component-oriented distributed model based on CORBA • dynamic, extensible, generic operation a foremost concern • standard MM programmingplug & play model for buildingapplications • RM-ODP model fordistributed binding ofcomponents operational primitive interfaces binding object binding object complementary stream interface stream interfaces

  6. Adaptation with TOAST • Open access to internal implementation of bindings • Minor: access control interfaces of relevant components to make tweaks • Major: alter the graph-style structure of a binding implementation • add new components • remove unwanted components • replace components Meta-Interface MPEG Video Binding RTP Binding Raw Raw MPEG MPEG RTP RTP Video Video Video UDP Binding Video Sender Receiver Source Sink Encoder Decoder

  7. The Visual Beans Project • Approach: integrate visualization into the TOAST middleware platform • componentize visualization system • algorithms • interaction between components • construct distributed visualization applications using TOAST • Benefits • Integrated support for continuous media and visualization • easier more configurable support for inter-participant communications • ‘floor control’ extended to cover A/V and visualization/whiteboard • Resource management simplified • visualization and continuous media data use same platform & model • Support for adaptation via TOAST model • reconfigure apps/DCV sessions to meet network/CPU resources • alter ‘big picture’ as participants join/leave or change working style

  8. VisAD • Modular Java platform/toolkit for visualization applications • University of Wisconsin-Madison Space Science and Engineering Centre • Features • Open source, large and active user community • Principled data model including description/typing • Display support for Java2D and Java3D • mappings used to render data to particular display attributes • Basic architectural support for distributed collaboration • Drawbacks • Adopts Java AWT-style ‘listener’ model for component interaction • c.f. more traditional dataflow model of other MVEs • Distributed operation reliant on Java RMI • not particularly ‘open’ • Much intelligence contained in display code (e.g. mappings to contours) • Heavyweight! (Java3D…)

  9. VisAD

  10. Project Activities • Alterations to TOAST middleware platform • Port to Java for easier integration with VisAD • Incorporation of new information types for visualization • more varied data structures than usual continuous-media bytestreams • Visualization components • Identification in VisAD system architecture • Isolation and wrapping as TOAST components • Integrate with bindings and distributed communication components • Collaboration application work • Re-engineering of MANICORAL demonstrations • Introduction of audio communications using TOAST components • Adaptation scenarios…

  11. Visualization on PDAs • Recent explosion in popularity • Entering the ‘useful’ arena in capabilites: • Colour (12-bit) screens of useful sizes (240x320) • 64M ram • ~200MHz RISC CPU • Built-in audio capabilities • Wireless LAN capabilities / dialup cellular access • Desirable to extend DCV to PDAs • Small size makes ideal for carrying in the field • May need assistance from desk-bound colleagues • e.g. isolate manageable portions of data • Issues • Standard visualization platforms too heavyweight to run (VisAD) • Datasets too large for available storage (64M - OS - apps - files = ?) • Network connectivity may be variable (c.f. laptop user!)

  12. Visualization on PDAs • Approach • Extend visualization middleware onto PDA • Use middleware to allow PDA to join DCV session by proxy • Proxy architecture (work in progress) • capture rendered output on proxy as a video stream • bandwidth & CPU resource requirements then fixed at well-known values • transmit to PDA via TOAST facilities • compression • adaptation (e.g. with audio stream) • feed user input/actions into visualization session via proxy

  13. Summary • Distributed Cooperative Visualization a growing area • Audio/video communications enhance/allow cooperation • Visual Beans investigating component-based middleware for distributed cooperative visualization integrating multimedia communications and support for adaptation • Looking at extending reach of DCV to PDA platforms http://www.acu.rl.ac.uk/VisualBeans

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