overview of mobile computing (2): applications and services
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Overview of Mobile Computing (2): Applications and Services
The iMode Story: It is About Services!
• 27M Internet-capable cell phone sub-scribers (10/01); 50K iMode Web Sites
• World’s largest ISP, first to deploy 3G“Freedom of Multimedia Access” (FOMA)
• Not just about Japanese teenagers
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Applications Used User Ages
Economist Magazine, 13 Oct 2001
In the post-PC age…
• Not just about gadgets or access technologies• About services and applications, and how the
network can best support them• Increasing, not decreasing, diversity• Bottlenecks moving from core towards edge• Enabled by computing embedded in communications
fabric: wide-area, topology-aware, distributed computing
Services for Mobile Networks
How to build services for end users in a mobile and wireless networking environment:
• Issues and service types
• One example: universal interactor,
Grand Goal of “AAA” Mobile Services
AAA Service: “Any time, Any where, Any form” service
• Any time: it is about wireless (time-domain quality)
• Any where: it is about mobility (space-domain quality)
• Any form: it is about device diversity (systems quality)
Issues in building mobile services
• Mobility induced issues:– Seamless services: service migration– Location services: location itself is a service
• Heterogeneity induced issues:– Hardware diversity
• Client devices & different networks
– Software diversity• System software: OS, networking protocols• Application software
• Wireless induced issues:– Time-varying network connectivity: disconnection,
partial connection, full connection
Possible services types1. Location service
2. Location-transparent services– Hide locations from users: same as old Internet
3. Location-dependent services– Services “local” to a geographic location
– Not available globally
4. Location-aware services– Services are globally available, but multiple
instantiations of the same service are a function of locations
– Service adapts to a location
How to Provide Location Services• GPS at every node
• GPS at a few reference points– Build recursive location services through
reference hierarchy
• Geometric triangle computation– Cricket system
• Identify the current cell
• What about location tracking?
Services• Location transparent services:
– If lower-layer provides mobility support, this is not a big issue
• Location-dependent services:• Local currency exchange when visiting foreign
country• Location aware services:
– example: finding a nearby bookstore while driving
– Issue: service migration from old server to the new server
– Solution: location-adaptive
Building context-aware applications?
• Context is a key factor for mobile computing– Typical context: time, location coordinate, personal
profile, etc.
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Typically: Identity, location, time•Rest is implied•Not much else used: activity, mood, etc.
QuickTime™ and aTIFF (LZW) decompressor
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QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
Design Process Using Tools?
For your information only
Not required for the exam
QuickTime™ and aTIFF (LZW) decompressor
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QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
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