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Some Computer Science Issues in Ubiquitous Computing. Mark Weiser Communications of the ACM, July 1993. Presenter : Junghee -Han. Contents. What was Ubiquitous Computing in 1993 ? Hardware prototypes Issues of Ubiquitous Computing Hardware components Network protocols - PowerPoint PPT Presentation
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Some Computer Science Issuesin Ubiquitous Computing
Presenter : Junghee-Han
Mark WeiserCommunications of the ACM, July 1993
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
Contents
2
Very new to the field of Computer ScienceUbiquitous 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 in 1993
3 Ubiquitous Computing
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 in 1993
4 Ubiquitous Computing
Virtual Reality puts people inside a com-
puter-generated world
Ubiquitous Computing forces the computer to live
out here in the world with people
VR vs. Ubiquitous Computing
5 Ubiquitous Computing
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
6 Ubiquitous Computing
Large-Size Prototype LiveBoard Main idea was to simulate a office whiteboard Order of 1 per office Xerox product
Hardware Prototypes
7 Ubiquitous Computing
Hardware Prototypes
8
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
Hardware Prototypes
9
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
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
The Computer Science of UbiComp
10 Ubiquitous Computing
Low power Work to reduce power rather than to increase per-
formance 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 awayThere is a need to balance
performance and power usage
Issues of Hardware Components
11 Ubiquitous Computing
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 IPEnabling media access whilecontinuously moving between spaces
12 Ubiquitous Computing
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 re-
quires 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
13 Ubiquitous Computing
Applications The location of people Information about Location can be deduced from lo-
gins 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 orsame pages
Location aware andallowing multiple users
14 Ubiquitous Computing
Privacy of Location In cellular system Traveling pattern of cellular phone user can be de-
duced 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
informationTransmission and sharing of datamust be evaluated in a social context
15 Ubiquitous Computing
Computational Methods
16
Optimal Cache Sharing Problem Optimal strategy for partitioning memory between
compressed and uncompressed pagesRequires methods to handle cachemisses over high latency mediums
Ubiquitous Computing
Conclusion
17
Ubiquitous Computing is Making many computers available throughout the
physical Environment While making them effectively invisible to the userUbicomp seems likely to provide a framework For interesting and productive work For many more yearsHave much to learn aboutthe details
Ubiquitous Computing