.NET Mobile Application Development The Challenge of Mobility

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.NET Mobile Application DevelopmentThe Challenge
of Mobility
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Introduction

• Many mobile applications are clients in larger
  distributed systems
• In the last session we considered
• Characteristics of distributed applications
• In this session we will look at
• Mobile devices
• Mobile devices as clients in distributed
  applications
• Particular challenges of mobile devices

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The Mobile Revolution

• Computers no longer tied to the desktop
• Devices are increasingly mobile and wirelessly
  enabled
• Personal Digital Assistants (PDAs)
• Mobile phones
• Smart phones
• Mobile device usage is common
• 75 of UK population own a mobile phone
• Mobile devices will increasingly be used as
  clients in distributed applications
• Developers must address peculiar mobile device
  characteristics

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Pervasive Computing

• A vision of 21st Century computing
• Available any time, any place, in any device
• Pervasive computing
• computing power freed from the desktop
  embedded in wireless handheld devices,
  automobiles, home appliances and commercial
  tools-of-the-trade. In the enterprise it extends
  timely business data to workers in the field In
  our personal lives, it expands our freedom to
  exchange information anytime, anywhere IBM
• Devices are becoming
• more mobile
• more embedded
• casually connected to a ubiquitous network with
  wired core and wireless edges

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Visions of Pervasive Computing

• Users are predominantly mobile
• Computing is mobile and wirelessly connected
• Unmanaged, dynamic network environment
• Devices/appliances containing embedded computing
  are clients in this distributed environment
• Business domain / distributed wireless office is
  an ultimate goal
• Mobile phones, PDAs, laptops, corporate servers
  seamlessly integrated in wireless network
  environment
• Workers can access info and resources needed to
  do their job regardless of their location

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Mobile Devices

• Many different mobile devices
• Laptops/Tablet PCs
• Essentially same as standard desktop PCs
• Personal Digital Assistants
• Pocket-sized handheld computer with
• Calendar, contact management, note taking, Web
  browser media player apps
• Pen interface
• 802.11/Bluetooth/GPRS connectivity
• Mobile Phones
• Smaller than PDA primarily a telephone with
  extra functions
• Current devices are 2.5G digital/GSM
• 3G devices becoming more common
• Smart phones
• Hybrid between mobile phone and PDA with mobile
  phone form factor

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PDA Characteristics

• Typical spec
• CPU up to 400 MHz RISC processors
• Memory 8 128MB RAM for programs and file store
• Screen 6cm x 8cm
• Stylus for input with handwriting recognition

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Mobile Phones

• Evolved over three generations
• 1st generation analogue phones
• 2nd generation
• Voice centric, GSM digital phones
• Low bandwidth data access via SMS, WAP
• 2.5 generation most current phones
• Higher data rates via GPRS EMS, MMS
• Effectively always on network connection
• Personal management apps calendar, contacts
• 3rd generation
• Goal is complete personal communication system
• Broad bandwidth data connections
• Streaming multimedia, video telephony and full
  Internet access supported
• Predictions suggest that number of mobile phones
  connected to Internet will exceed number of
  Internet connected PCs by 2007

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Mobile Phone Characteristics

• Typical spec
• CPU lt 200 MHz RISC processors
• Memory lt 32MB RAM for programs and file store
• Screen Typically 3.5cm x 4.5cm or less
• Input via numeric keypad
• Must behave as advanced (not thin) client and
  smoothly transition between being networked and
  self-sufficient device

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Common Characteristics

• Physical
• Small and light enough to be carried about the
  person gt size screen resolution constraints
• Power management
• Battery powered
• Must be designed to minimize power consumption,
  maximize battery life
• Always on
• Devices never completely powered down
• Boot sequence must be short
• Processor speeds/power consumption increased
  greatly over recent years
• Battery technology improvements have not kept
  pace

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Common Characteristics

• Memory and storage
• Limited memory capacity (compared to PCs)
• Slower than desktop memory
• Memory used for file storage and running programs
• Network connectivity
• Intermittent connection
• Devices do not have permanent connection
• Need to cope gracefully with service
  interruptions and disconnected operation
• Variety of networks
• Different networks encountered at different times
• Must manage and use these seamlessly
• Security
• Device often contain valuable/sensitive data
  personal and business (e.g. connection to
  corporate gateway)
• Small devices easily lost or stolen
• Good range of security and authentication
  features required (e.g. biometrics)

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Common Characteristics

• Telephony
• Many mobile devices offer voice telephony support
• OSs must provide comprehensive telephony
  services and make these available to other
  devices
• Processors
• Mostly ARM-based
• Similar architecture to desktop CPUs
• Lack some features of general purpose desktop
  processors due to competing constraints of size,
  power consumption and hardware features
• Operating Systems
• Specialized OSs required targeted at custom
  chipsets used
• Trimmed down desktop OSs not appropriate
• Three key OSs used in majority of mobile devices
• PalmOS PDAs
• Symbian Mainly phones
• Windows CE .NET Pocket PC (PDA) and SmartPhone
  (Mobile phones)

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Mobile Services

• Each mobile platform provides fundamental set of
  services
• PDAs
• Internet access, e-mail, personal information
  management (PIM), office apps
• Configurable by owner
• SmartPhones
• As PDAs, plus voice telephony and messaging
  (SMS/EMS/MMS)
• Mobile phones
• Voice telephony, WAP, SMS/MMS, limited PIM
• Configuration fixed by manufacturer/network
  provider
• User personalisation possible

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Location Awareness

• Fundamental feature of many mobile devices
• Legal requirement for mobile phones in UK/USA
• Location determination for calls to emergency
  services
• Commercial applications also leverage this
  location awareness
• Tracking and logistics
• Embedded devices in delivery trucks to monitor
  operations and deliveries
• Automobile remote diagnostics and telemetry
• Location-based information and data
• Services provided to mobile user based on
  geographical location (e.g. maps, nearest
  chemist, etc)
• Location awareness becoming increasingly
  important
• Incubating new business models and applications
  (e.g. smart environments)

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Mobile Applications

• Mobile applications are inherently distributed
  client-server apps
• Two models of interaction
• Pull products / services
• Traditional model most desktop apps are
  pull-based
• User makes explicit request for info/service
  (e.g. Web browser)
• Push products / services
• Automatic - no explicit request required
• Data sent to user based on known user preferences
• Fit well with mobile devices due to availability
  of messaging services, etc (e.g. delivery of
  stock quotes or sports results via SMS)
• Innovative services result from combining with
  location-awareness
• Innovative uses of mobile technology and mobile
  applications are emerging
• e.g. wireless vending machines, information
  kiosks, wearable computing

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Summary

• In this session we have discussed
• Common mobile devices
• Mobile device characteristics and limitations
• Mobile applications and services
• In the next session we will begin to consider the
  software technologies used in implementing mobile
  applications

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Reading and Resources

• Reading
• Uwe Hansmann et al., Pervasive Computing
  Handbook, Springer-Verlag, 2001
• Geoffrey Elliot and Nigel Phillips, Mobile
  Commerce and Wireless Computing Systems,
  Addison-Wesley, 2004
• Deitel, Deitel, Nieto Steinbuhler, Wireless
  Internet and Mobile Business How to Program,
  Prentice Hall, 2002