Some Computer Science Issues in Ubiquitous Computing

1. Some Computer Science Issues in Ubiquitous Computing Mark Weiser Communications of the ACM, July 1993 Presenter : Junghee-Han

2. Contents • What was Ubiquitous Computing in 1993 ? • Hardware prototypes • Issues of Ubiquitous Computing • Hardware components • Network protocols • Interaction Substrates • Applications • Privacy of location • Computational Methods • Conclusion

3. Ubiquitous Computing in 1993 • Very new to the field of Computer Science • Ubiquitous Computing was 1st defined by Mark Weiser at Xerox Palo Alto Research Center(PARC) in 1991 • Three Waves of Computing • Main Frame • Many Person - One Computer • Personal Computer • One Person - One Computer • Ubiquitous Computing • One Person - Many Computer Ubiquitous Computing

4. Ubiquitous Computing in 1993 • Ubiquitous Computing is • Next-generation computing environment • Each person is interacting with hundreds of nearby wirelessly interconnected computers • Essentially invisible to user • New kind of computers of all sizes and shapes will be available to each person • Ubiquitous Computing is • Quite different from personal digital assistants • Computers should be autonomous agents • The Challenge is • To create a new kind of relationship of people to computers Ubiquitous Computing

5. VR vs. Ubiquitous Computing • Virtual Reality • puts people inside a computer-generated world • Ubiquitous Computing • forces the computer to live out here in the world with people Ubiquitous Computing

6. Hardware Prototypes • The physical world comes in all size and shapes • Three different sizes of devices • Large-size: Liveboard • Medium-size: Xpad • Small-size: ParcTab • A pervasive part of everyday life • With many active at all times Ubiquitous Computing

7. Hardware Prototypes • Large-Size Prototype • LiveBoard • Main idea was to simulate a office whiteboard • Order of 1 per office • Xerox product Ubiquitous Computing

8. Hardware Prototypes • Medium-Size Prototype • Xpad • Main goal was to simulate a personal notebook • Order of 10+ per person • Design focus • The right balance of features • The requirements • for particular features • Ease of expansion and modification Ubiquitous Computing

9. Hardware Prototypes • Small-Size Prototype • ParcTab • Information doorway • Main goal was to simulate PostIts • Order of 100+ per person • Design Philosophy • Put devices in everyday use • Design Problem • Size and Power Consumption Ubiquitous Computing

10. The Computer Science of UbiComp • To construct and deploy prototypes • Need to readdress some of the well-worked areas of existing Computer Science • Organization of a computer system • Hardware components • Network protocols • Interaction substrates • Applications • Privacy of location • Computational methods Ubiquitous Computing

11. Issues of Hardware Components • Low power • Work to reduce power rather than to increase performance • Wireless • Permits reuse of the same frequency again • Permits transceivers that use low power • Infrared Pens • Work over large area • Need not touch the screen • Operate from several feet away • There is a need to balance • performance and power usage Ubiquitous Computing

12. Network Protocols • Wireless media access • Use Multiple Access Collision Avoidance (MACA) • For fairness • • Same back-off parameter for all neighbor stations • Real-time protocol • To support multimedia applications • Mobility support • Device in one region moves • other regions • IP can’t solve this: Mobile IP • Enabling media access while • continuously moving between spaces Ubiquitous Computing

13. Interaction substrates • Tabs • Have a very small interaction area • “Touch typing” that uses only a tiny area • Liveboards • Using conventional pull-down or pop-up menus requires walking across the room • Location-independent interaction is need • X-window system • User may move from device to device, • and want to bring windows along • Window migration tools • Removing technical barriers • between user and device Ubiquitous Computing

14. Applications • The location of people • Information about Location can be deduced from logins or collected from an active badge system • Update the location database • Shared meeting tools • Pen-based drawing on a surface • Several users simultaneously operate independently on different or • same pages • Location aware and • allowing multiple users Ubiquitous Computing

15. Privacy of Location • In cellular system • Traveling pattern of cellular phone user can be deduced from the roaming data • Much worse in ubiquitous computing • Preserving privacy of location • Central DB of location information • Store information at each person’s PC • Short-term accumulation of location • information • Transmission and sharing of data • must be evaluated in a social context Ubiquitous Computing

16. Computational Methods • Optimal Cache Sharing Problem • Optimal strategy for partitioning memory between compressed and uncompressed pages • Requires methods to handle cache • misses over high latency mediums Ubiquitous Computing

17. Conclusion • Ubiquitous Computing is • Making many computers available throughout the physical Environment • While making them effectively invisible to the user • Ubicomp seems likely to provide a framework • For interesting and productive work • For many more years • Have much to learn about • the details Ubiquitous Computing