[email protected]
Research Issues in Adapting
Computing to Small Devices
Francis C.M. Lau
Department of Computer Science
The University of Hong Kong
APPT 2005 • Hong Kong
Popular Computing
• 70’s: one computer, many users
• 80’s: one computer, one user
• 90’s: many (connected)
computers, many users –
distributed computing
• Now: many computers, one user
• What next? Ubiquitous computing?
Grid computing? Service-oriented
computing? …
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– Do we need that many computers?
– Do we need a “computer”?
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Windows Panic
• Continue or
quit or kill the
window or
details?
• How would my
mother know!?
• The best
computing is
without the
computer
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Imagine …
• APPT 2015 (Disneyland, Hong Kong) …
APPT 2015
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My Future Handheld
• All in one: phone, PDA, wallet,
game console, remote terminal,
ad-hoc networking …
• That means a lot of software –
big and fat!?
• But what I really want is lean
and thin and mean
– Lean – simple software which does
only what I want
– Thin – that’s all the space in my
pocket, or around my neck!
– Mean – affordable
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LTM
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LTM Computing
• The (thin-) client-server
paradigm, works but in
limited ways
• Too thin: a browser-only
device, a remote terminal …
• Future devices are more
powerful than just that
– But how powerful is powerful?
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O my god!
Software
complexity
Subramanian, 1999
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Rich Computing
• My hard disk and VM can be as big as
the Internet
• Not just contents, but software come
and go on demand
• Pay-per-use subscription model
• Browser plug-in’s and Java applets –
not lean enough, and some require
just too much resources
• Software in terms of “functionalities”
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The Network
is the Computer ™
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The Network Behind Every Device
• Future digicams
– Snap and go
• The network is the memory
• The network is the photo album
• (The network is NOT the power)
– Context aware
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Edge Computing
• Person .. device ..
middleware
(proxies) ..
Internet
• The abstract
cloud moves with
the client –
personalized
“cuddleware”,
nomadic
computing
proxies united
Internet
metropolis
client
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The continuum: WHAT SHOULD BE DONE WHERE?
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A Continuum
• Your device .. other devices (peers) in the
vicinity .. server(s) nearby .. the grid
– “Neighborhood” is still important
• network bandwidth can’t be infinite; latency will
never be 0; network will never be trouble-free
• What should be done where?
– The end-device: completely passive (HAS) to
completely active (DIY)
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“Hire a Server”
• Completely passive (remote terminal)
– A waste of bandwidth
– Responsiveness and interactivity (esp. for
games)
• Does it make sense?
– MP3, camera, PDA, …
• Something must be done locally
– Adaptation
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Limits You Can’t Beat
• Power?
• Screen size: foldable, rollable,
wearable, projectable? Or do
without the screen (audible?)
– Convenience and privacy; and
power consumption
– Resolution helps a little bit
• Why I don’t use a PDA (I just
ordered an 24” LCD; but I still
look at my watch)
– Ergonomics is very important
– Scrolling is a nuisance (now)
– User experience!
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Wearable
Computers
server
display
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Adaptation
• Data
– = not code
• Content
– A special kind of data
– Text, paged, non-text
– Pixel level and/or higher
• UI
– Higher level, structural, interactive
– Buttons, icons, menus, panels and panes …
–  content
• Code
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Componentized Software
• Executable code as
puzzle pieces
• Fast start, like contents
• Software download
pipelining – first-comefirst-execute, the most
needed functionalities
first
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The Need for Code On Demand
• How many functions have you ever used?
A simplified view of Microsoft Word
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Remember UNIX?
• Small is beautiful
• Make each program do one
thing well
• Choose portability over
efficiency
• Store data in flat ASCII files
• Avoid captive user interfaces
• Make every program a filter
• …
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UNIX Philosophy Applied
• Small software components
implementing single functionalities
• Bigger functions runtimecomposable from small
components
• Download on demand, and
disposable
• Standard formats and interfaces
(eg. XML)
• Shared GUI
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Service-Oriented Computing
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Adapting X to Y
• Many issues
–
–
–
–
Psychology
Aesthetics
Readability, convenience, privacy …
Economics
• Context awareness
– Because small devices are likely mobile
– The user moves around
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Awareness and Adaptation
• An intelligent supporting
architecture
• Aware of the come and go of
mobile users
• Choices of functions, depending
on situation: the location, the
device, the user, …
• Fast reacting nearby proxy
• Proxies united, within certain
locality
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Summary 1: Basic Problems (I
think) Worth Pursuing
• Edge computing → “seamless”
– New protocols for the edge
• The continuum → the network is the computer
– Collaborative models and mechanisms, esp. at the edge
• The global grid → invisible, “PC” disappearing
• The device
– Adaptation
• On-demand code composition
– The SOC approach?
• Content
– HTML
• UI description languages
– New paradigms for user interaction in small devices (input and
output)
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Some HKU Projects
• The Sparkle Project – “code adaptation”
• PDF document content adaptation
system – “content adaptation”
• HTML adaptation – “UI/content adaptation”
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Application = “facet”
composition
Sparkle
• Mobile code on demand
– Proxy to device, device to device
• Features
–
–
–
–
–
–
Code On Demand
Context Based Adaptation
Proxy Caching on Code
Code & State Migration
Ontology
Sparkle View & Universal Browser
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Universal Browser
5000
4500
Time (ms)
4000
3500
3000
2500
2000
1500
1000
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500
27
0
Add Noise
Add
Find
Flip
Flip Gaussian Open
Shadow Edges Horizontal Vertical
Blur
Image
Save as Sharpen
Jpeg
PDF Document Adaptation
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Web Document Adaptation
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(a) The original content
(b) Only the bottom level
is “compressed”
(c) The two lowest levels
are “compressed”
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Handling Segments
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Summary 2: When I Grow Older
• I want a simpler life (others can enjoy all
the complexities)
– One device, LTM
– No computer please; terminal is fine; plug and
play
– Single data storage by hire, access anywhere
– Single sign-on, single environment (adaptive)
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