Ensembles

1
Ensembles

• Ubiquitous Computing
• Spring 2007

2
Readings

• Device Ensembles
• By Bill N. Schilit and Uttam Sengupta
• What We Carry (sidebar)
• By Ken Anderson, Michele Chang, and Scott
  Mainwaring
• User Interfaces When and Where They are Needed
  An Infrastructure for Recombinant Computing
• By Mark W. Newman, Shahram Izadi, Keith Edwards,
  Jana Sedivy, and Trevor Smith

3
Device Ensembles Overview

• Problem
• People juggle a multitude of devices and they
  dont interact well.
• Goal
• Devices should work as an ensemble, playing
  effortlessly with each other.
• Future Usage
• In the future, people will have ensembles with
  more than just their own personal devices.

4
Problem Scenarios

• How do I get my cellular handset to share phone
  numbers with my notebook computer?
• How do I shuffle photos from my camera, when its
  memory card fills up, to my digital camcorder?
• How do I check incoming SMS messages on my game
  console?
• How do I network my PDA through my cell phones
  GSM data channel?

5
Why cant one device do everything?

• When one machine does everything, it in some
  sense does nothing especially well, although its
  complexity increases. -Don Norman

6
Standards

• Digital Living Network Alliance providing
  guidelines to improve interoperability among home
  media devices.
• Made progress in important ensemble usage
  scenarios.
• Lots more to do.

7
Layers of interoperability

• Link layer low-power, short-range communication
• Network layer to route IP through the best
  connected device
• Data layer to share and sync information
• Application layer create apps that can span
  multiple devices

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Link Layer

• Spans both LANs and PANs with properties
  including low power, medium to high bandwidth,
  and always-on connectivity.

9
Link Layer examples

• Ubiquitous technologies
• Infrared
• Universal Serial Bus
• Firewire

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Link Layer examples

• Current technologies
• Bluetooth
• Wi-Fi

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Link Layer examples

• Emerging technologies
• Ultrawideband
• ZigBee
• Near Field Communication

12
Network Layer examples

• Current technologies
• Jini
• Universal Plug n Play
• Personal Mobile Gateway

13
Data Layer

• Data synchronization sync mobile devices with
  desktop/server computers and other mobile devices
• Data transfer send info when needed rather than
  syncing across devices
• Data formats have to translate data to
  appropriate format to handle ensemble
  interoperability

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Data Layer examples

• Data synchronization
• FastSync/SlowSync
• Open Mobile Alliance
• P2P synchronization
• Internet Suspend/Resume

15
Data Layer examples

• Data transfer
• BlueFS
• Segank

16
Application Layer

• Ensemble end-user services.
• E.g. devices that act as user interface
  peripherals for another

17
Application Layer examples

• Clicker application converts phone into remote
  mouse
• Email apps on notebook computer vs. BlackBerry
  device
• CrossWeaver system designers sketch interface
  ideas for multiple devices and turn these into
  working prototypes

18
Device Ensembles Takeaways

• People now have a multitude of devices and move
  between them depending on the task.
• Need to clarify usage models to design standards
  and solutions for ensembles.
• Highlight Clear outline of four layers to
  communicate the capabilities of ensemble
  computing. Provided current, grounded examples of
  these different layers.
• Questions Integrate these layers into a single
  technology?

19
What We Carry

• Study of technosocial device ensembles and
  usage models

20
What We Carry User findings

• People carry cell phones, laptops, wallets, MP3
  players, reading material
• All possessions reflect different aspects of how
  people represent themselves

21
What We Carry Changes

• Macro changes vs. Micro changes
• There should be easy migration of information and
  identity between devices.

22
What We Carry Too many devices!

• Every device needs too many supporting devices to
  work effectively.
• User need people want simpler technology that
  just works in order to fulfill their tasks
• Example Wi-Fi makes life simpler.

23
What We Carry Coordination

• Not just syncing information.
• Coordinating information isnt just an archiving
  problem its a practical one that occurs in
  real time.
• Users need a seamless way to switch between and
  coordinate devices

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What We Carry Takeaways

• People use multiple devices to fulfill a need for
  bounding identity and function.
• Mobile devices do not interact as seamless
  ensembles yet.
• Highlight Captured user needs within their
  social context.
• Question Do users feel the need to maintain
  multiple devices so we need to enable that
  coordination? Can we combine functionality in
  some ways?

25
User Interfaces When and Where They are Needed
An Infrastructure for Recombinant Computing

• Understanding the spontaneity of using and moving
  between different technologies.

26
What is recombinant computing?

• Recombinant computing enables devices/services
  to recombine without planning.
• Addresses current problems
• constrained by the difficulties in
  interconnecting devices and services
• need to plan in advance to overcome the
  interoperability challenges.

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Speakeasy

• Infrastructure for recombinant computing. Users
  can form new ad hoc combinations to meet their
  needs.
• Changes how devices discover each other and how
  they transfer data between themselves.

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Principles of recombinant computing

• Small, fixed set of generic interfaces
• Mobile code to extend behavior to other
  components at runtime
• Allowing user to decide when and how components
  will interact.

29
Framework overview

• Application requests session object from source
• Passes session object copy to the sink.
• Sink uses session to ask source for type handler
  to transfer data

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Speakeasy Requirement 1

• Component UIs must be able to find their way
  across the network to the user that is using
  them.
• Interfaces need to be delivered from external
  components to a remote client for users

31
Speakeasy Requirement 2

• Applications should not need to have specialized
  knowledge of every other component.
• Apps should be able to use UIs for components
  they have not seen before.
• UI can be downloaded on demand along with
  underlying logic

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Speakeasy Requirement 3

• Allow for the push and pull of UIs between
  components and clients
• Pull top level per-component UIs
• Push per-connection UIs

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Speakeasy Requirement 4

• Both applications and components have to detect
  and recover from partial failures.
• Is a remote peer down, just slow at responding,
  or momentarily disconnected?
• Need to detect these failures without explicit
  disconnection signals

34
Speakeasy Requirement 5

• Infrastructure should support different UIs,
  aggregated from different sources in a connection.

35
User Interfaces When and Where They are Needed
Takeaways

• Standardizing communication protocol is a good
  way to enable effective device interaction
• No need to predict interactions just follows
  the push/pull of UIs at runtime.
• Highlight an actual system framework developed
  to facilitate device ensembles.
• Questions What kind of problems can you foresee
  with this framework? Would it work in all use
  cases?