1 / 16

Some Computer Science Issues in Ubiquitous Computing

Some Computer Science Issues in Ubiquitous Computing. Communications of the ACM 1993 Mark Weiser Presenter: Junghoon Kim kjh@mmlab.snu.ac.kr. Contents. Introduction Paradigm Shift What is Ubiquitous Computing? Virtual Reality Ubiquitous Issues Design Approach Hardware Issues

floria
Download Presentation

Some Computer Science Issues in Ubiquitous Computing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Some Computer Science Issues in UbiquitousComputing Communications of the ACM 1993 Mark Weiser Presenter: Junghoon Kim kjh@mmlab.snu.ac.kr

  2. Contents • Introduction • Paradigm Shift • What is Ubiquitous Computing? • Virtual Reality • Ubiquitous Issues • Design Approach • Hardware Issues • Network Protocols • Interaction Substrate • Applications • Privacy of Location • Computational Methods • Summary

  3. Introduction - Paradigm Shift- What is Ubiquitous Computing?- Virtual Reality

  4. Paradigm Shift • Challenge • Create a new kind of relationship of people to computer • Traditional computer • Isolated from the overall situation • Needed to attend to use • Future computer • Intimate computer • Rather like a human assistant

  5. What is Ubiquitous Computing? • Definition • Ubiquitous computing enhances computer use by making many computers available throughout the physical environment, while making them effectively invisible to the user

  6. Virtual Reality • From rising star to fallen angel • Believed to enact the principles • Makes it possible for computers to get out of the traditional work way (supports intuitive interaction) • Problems • Very expensive to provide sufficiently realistic simulation • Cuts people from real world

  7. Ubiquitous Issues - Design Approach- Hardware Issues- Network Protocols- Interaction Substrates- Applications- Privacy of Location- Computational Methods

  8. Design Approach ParcPad ParcTab Liveboard • New artifact • Used in everyday life • Types • Liveboard • Large ones used as shared display surfaces • Pad • Near megabit wireless communication bandwidth • Always ran XWindows • Tab • Power is a major issue, cannot always change batteries • Used COTS Intel 8051 microcontroller • Small touch-sensitive display screen

  9. Hardware Issues • Low power • Reduce Power Consumption • Power = Gate Capacitance × Voltage × Clock Frequency • Wireless • Metric: Bits/sec/meter3 • Electromagnetic spectrum range • Power fall-off r6 • Pens • Casual use, no training, naturalness, simultaneous multiple use • PARC devised a new infrared pen

  10. Network Protocols • MACA (Multiple Access with Collision Avoidance) • Used to avoid “Hidden terminal” • Fairness • Same back-off parameter for all neighbor stations • NCTS(n) (Not Clear To Send) • Other network issues • Gb networks for real time data • Important for multimedia data • Mobility • Existing IP dose not support mobility • Virtual IP • Mobile IP

  11. Interaction Substrates • Different interaction area • Tab (small), liveboard(huge) • X-Window system • Designed for network • Does not provide mobility • To solve this problem, Jacobi developed new X-window toolkit • Different bandwidth • Vary from Kbps to Gbps • Use low bandwidth

  12. Applications • Locating people • Data acquired from: • Logins to workstations/terminals • An Active badge system • Useful for • Automatic call forwarding • Shared Drawing Tools • Shared draw • Data Representation • Tivili-Object based • Slate-Pixel based • UI Issues • How to handle multiple cursors? • Use gestures or not? • Use an ink based or character recognition model of pen input?

  13. Privacy of Location • Location information • Important for routing • Need to be protected • Solutions • Central DB of location • Privacy controls can be centralized • But one break-in there reveals all • Transmission of the location information to a central site • Centrality is unlikely to scale worldwide • Storing information about each person at that person’s PC • Programs must query the PC, and proceed through whatever security measures the user has chosen to install

  14. Computational Methods • Cache sharing problem • Classical distributed computing problem • Processing power > Link speed • Pages are often compressed • Compare online algorithm with offline algorithm • Offline algorithm is better than online

  15. Summary - Conclusion

  16. Conclusion • What is ubiquitous? • Issues of ubiquitous computing • Tab, Pad, Liveboard • Ubicomp is likely to provide a framework for interesting and productive work for many more years • Have much to learn about the details

More Related