Software Engineering for Mobility: A Roadmap

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Software Engineering for Mobility A Roadmap

• By Gruia-Catalin Roman, Gian Pietro Picco, Amy
  L. Murphy

Kamal Rupareliya, Ido Carmi
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Embedded Systems Mobility

• Embedded systems have limited resources
• Transfer computation to other systems
• Access resources not on host machine
• May be mobile by nature cell phones hand-held
  devices.

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Coordination What happens when mobile programs
meet.

• How do they recognize each other?
• How do they exchange information?
• How do they construct complex cooperative
  behavior?

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What is mobility?

• Physical
• Movement of hosts in physical space room,
  building, country, world, galaxy.
• Location in physical world.

• Logical
• Movement of code state among hosts.
• Location in network.

Challenge Incorporate both notions of mobility
into one framework.
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Complication Unstable Networks

• Nomadic
• Physically Central servers with fringe of mobile
  hosts that come go.
• Logically Napster

• Ad-Hoc
• Physically No central servers, everyone comes
  and goes.
• Logically Gnutella

How can a single middleware be compatible with
both scenarios?
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Location vs. Context

• Location
• Where am I?

• Context
• What do I see?
• Defines the environment where the computation
  associated with the unit is performed.

• Location context are independent
• Different locations may produce the same
  context.
• Same locations may produce different context (if
  program has different privileges).

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Middleware Coverage

• Horizontal Coverage
• Deals with broad range of scenarios.
• Little domain-specific functionality available to
  developers.
• Limit by setting.
• Example a platform which provides abstractions
  that span from fixed to ad hoc networks.
• Prism Designed to run on multiple types of
  platforms.

• Vertical Coverage
• Deals with a specific scenario.
• High level of functionality for task at hand.
• Limit by constructs.
• Example Providing support for ad-hoc networks
  only.
• Prism Designed for nomadic networks.

The challenge Finding the right balance of
coverage by the middleware and at the same time
making it useful for real world applications.
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Middleware Coordination

• Implicit
• Communication unknown to components
• Transparent variable sharing

• Explicit
• Communication specified by components.
• Facilitates application-specific optimizations.

• Challenges for mobility
• Rapid changes in context
• Lack of universal naming space (there is no DNS
  in ad-hoc networks)

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General Issues

• Paper gives good overview of applications,
  issues, and up-to-date technologies related to
  mobility.
• Some of the functionality described are entire
  fields of research
• It may not be possible (anytime soon) to
  incorporate localization in a single middleware
  solution more art than engineering.
• Context-awareness is very application-specific
  Context of mobile unit on Mars different from
  that of Palm Pilot on Earth.
• It may not be appropriate to define algorithms at
  this stage of research.