Pervasive

1
Pervasive Ubiquitous Computing

• Hao Chu (???)
• Lecture 2
• 2/23/2004

2
Administrative Announcements

• Course homepage is up.
• http//www.csie.ntu.edu.tw/hchu/ubicomp_course/ub
  icomp_course.htm
• Reading list, project overview, project ideas,
• Course WIKI page is up.
• How to use WIKI? by James

3
Vision and Challenges

• M. Weiser, The Computer for the 21th Century",
  Scientific American, September 1991.
• M. Weiser, Some Computer Science Issues in
  Ubiquitous Computing, Communications of the ACM,
  36(7)75-85, July 1993.
• M. Weiser, J. S. Brown, "The Coming Age of Calm
  Technology, 1996.
• M. Satyanarayanan. "Fundamental Challenges in
  Mobile Computing", Fifteenth ACM Symposium on
  Principles of Distributed Computing, May 1996.
• M. Satyanarayanan. Pervasive Computing Vision
  and Challenges, IEEE Personal Communications,
  August, 2001.

4
M. Weiser. The Computer for the 21th Century",
Scientific American, September 1991.
5
Two Key Points

• Ubiquitous computing is about computing so well
  integrated with our physical environment such
  that people fail to take notice of them.
• Computing being everywhere, yet fading into the
  background
• Computing becoming disappearing and invisible
• Location and scale are important issues.
• Adapt their behavior intelligentlly without
  complex AI
• Scale suitable to different tasks

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Examples of Disappearing Technologies

• Writing
• Electric Motors
• Micro-controllers in CEs
• They are everywhere (embedding hidden into
  physical objects), yet invisible.
• When a technology matures, they disappear!
• Maturity cheap, small, widely applicable, good
  usability,

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Why Good Technology Is Invisible?

• Invisible stays out of the way of task
• Like a good pencil stays out of the way of the
  writing
• Like a good car stays out of the way of the
  driving
• Bad technology draws attention to itself
• Like a broken, or skipping, or dull pencil
• Like a car that needs frequent tune-ups
• Computers are mostly not invisible
• They dominate interaction with them.
• Ubicomp is about making computers invisible.

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Ubicomp vs. Virtual Reality

• Should we live in virtual computing world? Or
  should computing come out and live in our
  physical world?
• VR is about simulating physical world putting
  people inside virtual computing world.
• Limited applications activities
• Ubicomp is about bringing computing to peoples
  physical world.
• Integrating with everyday objects and activities

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Ubicomp vs. Multimedia

• Multimedia grabs user attention for entertainment
  purpose.
• Ubicomp reduces user distraction, allowing people
  to focus on tasks.

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Intelligence

• Computing embedded and enhancing physical objects
• Achieve intelligence through interconnection of
  physical objects
• Wall talking to heating or projector
• Achieve intelligence through location awareness
  (without AI)
• Automated call forwarding, lighting control

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PARC Ubicomp Work (1991)

• Focus on devices that transmit display
  information.
• Device scale targets different tasks.
• Consider three sizes tabs, pads, boards.

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Tabs

• Inch-scale Ubicomp devices
• Post-It notes
• Carried around by a person
• Hundreds in a room
• Credit cards, ID cards
• Remote controllers
• Badges
• Tags / Labels (RFID)
• Locating system (tags as library catalogs)
• Animate static physical objects (active calendar,
  active map)

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Pads

• Foot-scale Ubicomp devices
• A sheet of paper / tablet PC
• Tens in a room
• Like scrap papers that can be grabbed and used
  anywhere, no unique ID.
• Like windows in Apple Macintosh, but can spread
  them out on a real desk.

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Boards

• Yard-scale Ubicomp device
• One in a room
• White board with e-chalk
• Shared white board with remote participants
• Video screen
• Electronic Bookcases

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Hardware Challenges (1991)

• High resolution flat panel display (cheap)
• High speed processor
• High capability storage
• High bandwidth wireless Network
• Lower power consumption
• How well do todays HW technologies meet these
  challenges?

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Software Challenges (1991)

• Dynamic configuration of HW/SW in ubicomp
  environments (device mobility)
• Application migration across heterogeneous
  ubicomp environments (user mobility)
• Transparent linking of wired and wireless
  networks
• Tiny range wireless, long range wireless, high
  speed wired
• How well do todays SW technologies meet these
  challenges?

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Sal Scenario

• Proactively brew coffee
• Electronic Trails of neighbor coming and going
  (Privacy issue)
• Automatic recording pen
• Email locating garbage door opener
• Window tells weather
• Share location info with Joe (Privacy Issue)

• Share tabs/pads with Joe (Miniaturization)
• Gesture to project blinking tab to projector.
• Memory augmentation on meeting with Mary.

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Privacy Issue

• Hundreds and thousands of invisible computers
  sensing and watching people
• A bit scaring?

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Misc

• Ubicomp as a Savor to Healthy Social Interaction?
• People dont have to hole up in windowless
  offices before computer screens all days.
• Ubicomp as relaxing as talking a walk in the
  woods

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Discussion

• Tradeoff between intelligence and privacy
• Tradeoff between invisibility and privacy
• What are killer ubicomp applications?
• Think about interesting scenarios for
  interconnecting home appliances
• AI ubicomp?
• Should computing stay out of the physical world?
• Human dependency on computing
• Environmental impacts
• Social impacts

21
M. Weiser. Some computer science issues in
ubiquitous computing.Communications of the ACM,
36(7)75-85, July 1993.
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Key Point

• Based on their PARC experiments with tabs, pads,
  and boards, this paper tries to define some
  ubicomp challenges and where ubicomp is going.

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Ubicomp as Experimental CS

• Construct working prototype
• Evaluate working prototype in everyday use.
• Importance of working prototype

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Hardware Prototype Issues

• Power consumption impossible to change batteries
  to many ubicomp devices frequently.
• Balance of HW/SW feature display, network,
  processing, memory, storage capability,
  multitasking, QoS, etc.
• Ease of expansion modification (integration vs.
  modular design)

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Hardware Issues

• Low-power computing
• High-speed wireless bandwidth (802.11g 54 Mbps)
• Pens for very large display

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Network Issues

• Wireless Media Access (802.11, Bluetooth,
  Cellular Networks)
• Quality of Services (RSVP, etc)
• Ubicomp devices changing network attachment
  (Mobile IP)

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Interaction Substrate Issues

• Interaction substrates are UI software for pens
  and screens.
• Handprinting recognition
• Voice recognition
• Display migration (follow-me display)

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Application Issues

• Applications are of course the whole point of
  ubiquitous computing.
• Locating people (active badges)
• Automated call forwarding
• Tracking down people for meeting
• Watching general activity in a building (feel in
  touch with surrounding environments)
• Shared drawing in virtual meeting
• Scalability to 5000 peoples (multicast for
  bandwidth efficiency)

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Location Privacy

• Centralized location database as one possible
  solution, but not scalable, single point of
  attack, one break-in reveals all.
• Move toward more distributed approach.

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Computational Method Issue

• Due to unpredictable network to ubicomp devices,
  (file) caching can be used to improve
  performance.

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Discussion

• Open .

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M. Weiser, J. S. Brown. "The Coming Age of Calm
Technology." 1996.
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Key Points

• The computing trends is moving toward many
  (hundreds of) computers sharing each of us. Since
  computers are everywhere, they better stay out of
  our ways. Weiser called it Calm technology.
• A proposed solution (Calm technology) is to place
  most information in periphery of our attention,
  but allow fast easy moving to center of our
  attention.

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(No Transcript)
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Computing Trends

• These trends are results of computing getting
  smaller, faster, and cheapers.
• Mainframe Era many people sharing a computer.
• PC Era one computer per person
• Internet Era (interconnecting PCs)
• Ubicomp Era
• many computers (everyday objects) sharing one
  person
• interconnecting everyday objects

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Ubicomp Era

• Cheap Thin servers in every household
  appliances.
• Average home appliances (Microwaves, TV, DVD
  players, etc.) have embedded processors, but
  they are not Ubicomp devices, because
• They are not networked.
• They are not connected to the Internet.

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Calm Technology

• Calm and uncalm technology differs how to engage
  our attention.
• Divide our attention into two parts periphery
  and center.
• Periphery is informing without overburdening
• E.g., driving a car, center roads and radio,
  periphery engine noise
• Calm technology can move easily quickly between
  periphery and center.

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Examples of Calm Technology

• Inner Office Windows
• Extend periphery to what are going on the hallway
• E.g., notice lunch gathering, meeting, but not
  distracting to work
• In comparison to open cubicles with low
  partitions
• Force too much to the center
• E.g., noises in the hallway can become
  distracting to work

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Dangling String

• Represent bits flowing over a wire through motion
  and sound.
• The output is (beautifully?) integrated with our
  physical environment.

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Discussion

• Is Ubicomp defined by the devices or user
  experience?
• Are inner office window and dangling string
  really calm and relaxing?
• Does Calm give more or less information?
• This is related to ambient display research. UI
  People know more about this research area?

41
M. Satyanarayanan. "Fundamental Challenges in
Mobile Computing", Fifteenth ACM Symposium on
Principles of Distributed Computing, May 1996.
42
Key Points

• What are fundamental challenges in mobile
  computing (What is so special about mobile
  computing)?
• Resource-limited mobile devices
• Mobility is hazardous
• Unpredictable wireless networks
• Finite power source
• Adaptation is key to mobility.

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Evolution from Distributed Systems to Mobile
Computing

• What are fundamental differences between
  Distributed Systems and Mobile Computing?
• Distributed systems Applications running over
  Computers Connected Over Network
• Mobile systems Applications running over mobile
  devices connected over wireless networks
• Mobile devices constraints resource-limited,
  finite power source, easy-to-lose (weak security)
• Wireless network constraints unpredictability
  bandwidth and frequent disconnections

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Adaptation is Key to Mobility

• Adapt applications to continuously changing
  computing environment (due to mobility)
• Power, network bandwidth / availability,

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Adaptation Strategies

• Need resource management at the system layer to
  allocate resources to different applications.
• Need application level semantics, e.g.,
  frame-rate, resolution, etc.
• The best approach is to have both application and
  system supports.

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Extended Client Server Model

• Traditional (thin) client (fat) server model in
  distributed computing needed adjustments to
  address unpredictable network, finite power, and
  performance.
• Extended client-server model (called smart client
  model) places some server functionalities to
  client.

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Coda Odyssey

• Coda supports application-transparent adaptation.
• It is distributed file system (FS).
• It can cache/hoard some parts of FS on client.
• It can support disconnected operations from FS
  cache.
• Odyssey supports application-aware adaptation.
• Adapt application quality/fidelity (e.g., video
  framework, resolution) based on dynamic network
  condition, power saving, and processing loads.

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Research Topics for Exploration

• Caching metrics (what to cache/hoard?)
• Caching coherence (Semantic callbacks and
  validators)
• Algorithms for resource revocation
• Agility (??) vs. stability (Analysis of
  adaptation)
• (Global) Resource estimation from local
  observations

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M. Satyanarayanan. Pervasive Computing Vision
and Challenges, IEEE Personal Communications,
August, 2001.
50
Key Points

• What are fundamental challenges in
  pervasive/ubicomp computing (What is so special
  about pervasive computing)?
• Effective use of smart spaces
• Invisibility
• Localized Scalability
• Masking Uneven Conditioning
• We will hear a distinguished talk from author
  directly.
• http//www.cs.uiuc.edu/news/dls/distlectpst.html

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Discussion

• What exactly is proactivity? How does it differ
  from adaptation?
• Is Ubicomp still about old technical issues ..
• Integrating different technologies, devices and
  services.
• Resource discovery protocol
• Optimization (different parameters such as power)
• Adaptation (with environments)