A Webbased nomadic computing system or CoolTown

1
A Web-based nomadic computing system (or
CoolTown)

• An article by Tim Kindberg and John Barton
• Reviewed by Odd Petter Slyngstad for DT 8107
  Distributed Systems, 6/10/2004

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Introduction

• Web properties relevant to nomadic computing
• Ubiquitous access pervasive computing
• Just enough middleware supports adaptation
• Locality global access not always necessary

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Nomadic Computing Issues

• Interaction with (local) environment as opposed
  to exchange of documents
• Inadequate model for resource discovery
• URLs cannot be used as routine identifiers too
  volatile
• Web is largely read-only
• but in CoolTown, things are different

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CoolTown (the nomadic computing model)

• Assumptions
• Nomadicity users are mobile
• Handy devices systems support PDA-like devices
• Wireless communications simple, fast I/O
  expected
• Heterogeneity these devices are diverse both by
  function and communication
• Fixed resources printers, kiosks, teller
  machines
• Wired backbone to support the fixed resources

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Sensing

• Automatic discovery, options
• IR RF
• Barcodes
• Electronic tags
• Optical recognition
• Direct (URL) vs. indirect (via resolver) sensing

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Example of PDA setup
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Context physical discovery

• User designates what is of interest in the
  context (both physical and virtual)
• Issues
• Discovery finding contexts resources
• Hierarchy and context overlap links
• Simple bootstrapping automatic root context
• Scope user defined

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Context physical discovery (2)

• Implementation
• Place managers
• Provides access to configuration of resources
• Acts as resolver, Web server (html, xml)
• Physical registration
• Designating what is relevant in the context, as
  well as where that context is relevant

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Exhibition hall example
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Exhibition hall example (2)

• Instantiation create new place context at the
  Place manager
• Physical linkage configure beacons/barcodes
• Collection sense identifiers for context
• Resolver configuration obtain web presences
• Registration insertion of URLs
• Presence-tying linking

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Exchange of Content

• Direct post (A)
• Simple push interaction
• Indirect post (B)
• links to other content
• Devices as clipboards temporary storage
• Setting options on the sink (C)

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Discussion

• Places (and their context) may include additional
  constraints (time of day), be active
• Context not necessarily tied to a place (could
  be almost anything)
• Investigating shared contexts (individuals,
  groups)
• Discovery registration mechanisms cell-based,
  triangulation, network discovery the developed
  process is an alternative, based on context
• Privacy unfamiliarity vs. transparency
• Spontaneous networking need content-oriented
  computing to succeed (web vs. Jini or CORBA
  presence)

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Conclusion

• - The ability to connect physical objects with
  their web presence is critical to CoolTown
• - The authors acknowledge that much work remains
  before nomadic computing can be realized on a
  large scale