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The principles and concepts behind Smartphones

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The principles and concepts behind Smartphones Powered By Docstoc
					Context-Aware
Computing
CSE494/598 Mobile Health
and Social Networking
Context awareness:
the essence of adaptability
   Context awareness
       Resource awareness
            Adapt to available resources (connectivity, nearby devices
       Situation awareness
            Adapt to the situation (mode, location, time, event)
       Intention awareness (?)
            Adapt to what the user wants to do
   Context awareness is found in humans
       We always adapt our behavior and actions according to the
        context (i.e. situation)
       Pervasive computing devices that ubiquitously accompany
        humans (such as smartphones) must adapt accordingly
            Or risk being disruptive and annoying
    Defining Context
    • Dictionary definition
        • “the interrelated conditions in which something exists or occurs”
    • Definition for pervasive computing
        • “any parameters that the application needs to perform a task without being
          explicitly given by the user”

    One definition [Schilit]:                       Another definition [Abowd & Mynatt]:
        Computing context:                               Social context: user identity and
         connectivity, communication                       human partner identities
         cost, bandwidth, nearby
         resources (printers, displays,                   Functional context: what is being
         PCs)…                                             done, what needs to be done
        User context: user profile,
         location, nearby people, social
         situation, activity, mood …                      Location context: where it is
        Physical context: temperature,
                                                           happening
         lighting, noise, traffic conditions
         …                                                Temporal context: when it is
        Temporal context (time of day,                    happening
         week, month, year…)
        Context history can also be                      Motivation context: why it is
         useful                                            happening (purpose)
Context (cont’d)
                                      Sensor
                                       data
   Other classifications of
    context:                                   Low-level
                                               context
                                                                      motivational
       Low-level vs High-level
        context                                             social                     user
       Active vs Passive context
   Putting it all together                                location                  computing

       Gather low-level context                                        temporal
       Process and generate                        high-level
                                     Context        context
        high-level context          processing
       Separate active from                                           active            passive
        passive context                                               context            context

       adjust
                                                                           Context-aware
                                                                            application
Context-Aware Application Design
   How to take advantage of this context information?
   Schilit’s classification of CA applications:
    1.   Proximate selection:
         1.   closely related objects & actions are emphasized/made easier to choose
    2.   Automatic contextual reconfiguration: adding/removing
         components or changing relationships between components
         based on context
         1.   Switch to a different operation mode
         2.   Enable or disable functionality
         3.   Context-triggered actions: rules to specify how the system should adapt
    3.   Contextual information and commands: produce different results
         according to the context in which they are issued
         1.   Narrow-down the output to the user using the context
         2.   Broaden the output to the user using the context

   Is this classification fundamental/inclusive?
Context-Aware functionality:
Examples
   System optimization:
     power-save    mode, silent mode etc
   Connection optimization:
     Protocol   selection, compression rate etc
   Application Functionality
    …
   Presentation
     Image   orientation, locale etc
Location-Based Services
   Requirements                          Issues
       Geocoder (convert street              Content providers – Telcos
        addresses to latitude /                jealously guarding own
        longitude), Reverse                    domain
        geocoder                              Proprietary software e.g.
       Address Helper (many                   Windows Live
        addresses inaccurate or               Price of map data varies
        incomplete)                            widely, very expensive in
       Map data                               some countries e.g.
                                               Australia
   Data Repository:                          Integration into customer’s
       Points of Interest data e.g.           web sites (API’s)
        pubs, restaurants, cinemas            Cognitive Routing – routing
       Business Directory                     / directions using
        (doctors, plumbers etc by              terminology relevant to user
        location)                              (e.g. resident c/f tourist)
       Location-based Inventory
LBS + Navigation
   Basic form of Location-based                     android.location
    services                                             Classes defining Android location-
      Map service (Geocoder)                             based and related services.
      “You are here” service                        Interfaces
      Route discovery and generation of                 LocationListener: Used for
       directions                                         receiving notifications from the
   Add-ons                                               LocationManager when the location
                                                          has changed.
        Voice-activated
        Adjust route to traffic and accident        Classes
         conditions                                      Address: represents an Address, i.e,
        Integration with calendar and                    a set of Strings describing a location.
         address book                                    Geocoder: handles geocoding and
              Notify target partner of arrival           reverse geocoding.
                                                         Location: represents a geographic
                                                          location sensed at a particular time (a
                                                          "fix").

                                                       Criteria: indicates the application
                                                        criteria for selecting a location provider.
                                                       LocationManager: provides access
                                                        to the system location services.
                                                       LocationProvider: An abstract
                                                        superclass for location providers.
LBS + Social Networking:
BuddyFinder App
   Mobile social networking meets
    location based services
   Mobile friend tracking & directory
    services
   Proprietary internal messaging
    connectable to any messaging
    service
   Friends become closer than ever
    because you know where they
    are
   Location from GPS+map service
        Extension of LBS+Navigation?
In-class excercise
 Group up by table
 Name a smartphone app (existing or
  imaginary) and identify its adaptability and
  context awareness
     Handling    variable resources
         Connection, battery
     Handling    variable context
         Location, time
In-class exercise, feedback

              Table 1        Table 2        Table 3         Table 4        Table 5      Table 6

Application   Google         Secure         Hitch-hikers    Party          Mood-based   Meeting
              maps           gateway                        Managemen      music        scheduler
                                                            t              player       (calendar
                                                                                        and email)
Context       • Your         Security       • Location      • Location     Situtation   Current
                location     gateway        • destination   • Partners     Mood         time,
                             availability                   • Neighbor’s                meeting
                                                              mood                      time
Adaptivity    • Center/zo    Pre-           Matching        Order list     Adjust       Notify of
                on to your   authorized     hitch-hikers    Playlist       music and    delays
                location     access         to drivers                     volume
Wireless
Communications
and Networks
         Wireless Networks




100 km                                Satellite


 10 km

                                             WMAN
                   2G       3G               (WiMAX)
  1 km

 100 m
                                    WLAN
                                    (WiFi)
 10 m
            WPAN
             (ZigBee,
            Bluetooth)
   1m


         10 kbps         100 kbps    1Mbps         10Mbps   100Mbps
Wireless Networks
   Cellular - GSM (Europe+), TDMA & CDMA (US)
           FM: 1.2-9.6 Kbps; Digital: 9.6-14.4 Kbps (ISDN-like services)
           Cellular Subscribers in the United States:
                 90,000 in 1984 (<0.1%); 4.4 million in 1990 (2.1%);
                  13 million in 1994; 120 million in 2000; 187.6 million by 2004 (Cahner
                  In-State Group Report).
                 Handheld computer market will grow to $1.77 billion by 2002
   Public Packet Radio - Proprietary
           19.2 Kbps (raw), 9.6 Kbps (effective)
   Private and Share Mobile Radio
   Paging Networks – typically one-way communication
           low receiving power consumption
   Satellites – wide-area coverage (GEOS, MEOS, LEOS)
           LEOS: 2.4 Kbps (uplink), 4.8Kbps (downlink)
Wireless Networks (Cont.)
   Wireless Local Area Networks
       IEEE 802.11 Wireless LAN Standard based systems, e.g., Lucent
        WaveLan.
            Radio or Infrared frequencies: 1.2 Kbps-15 Mbps
   Wireless Metropolitan Area Networks
       IEEE 802.16 Worldwide Interoperability for Microwave Access
        (WiMAX)
            Microwave frequencies (2.5-66GHz), broadband (<70MBps), metropolitan
             coverage (1 to 30 miles)
   Packet Data Networks
       ARDIS
       RAM
       Cellular Digital Packet Data (CDPD)
   Private Networks
       Public safety, UPS.
Wireless Local Area Network
   Data services: IP packets              Variant Connectivity
   Coverage Area: Offices,                    Low bandwidth and
    buildings, campuses                         reliability

   Roaming: Within                        Frequent disconnections
    deployed systems                           predictable or sudden
   Internet access: via LAN.              Asymmetric
                                            Communication
   Type of services: Data at
                                               Broadcast medium
    near LAN speed.
                                           Monetarily expensive
                                               Charges per connection or
                                                per message/packet


        Connectivity   may be weak, intermittent and expensive
Network support by Android
 android.net                                   android.net.wifi
     Classes that help with network access,      Provides classes to manage Wi-Fi
      beyond the normal java.net.* APIs.           functionality on the device. more...
      more...                                   Classes
 Classes                                         ScanResult:     Describes information
     ConnectivityManager: answers                 about a detected access point.
      queries about the state of network          WifiConfiguration: A class
      connectivity.                                representing a configured Wi-Fi network,
     DhcpInfo: A simple object for                including the security configuration.
      retrieving the results of a DHCP            WifiConfiguration.Protocol:
      request.                                     Recognized security protocols.
     MailTo: MailTo URL parses a mailto          WifiConfiguration.Status:
      scheme URL and then can be queried           Possible status of a network
      for the parsed parameters.                   configuration.
     NetworkInfo: Describes the status of        WifiInfo: Describes the state of any
      a network interface of a given type          Wifi connection that is active or is in the
     Proxy: A convenience class for               process of being set up.
      accessing the user and default proxy        WifiManager: This class provides the
      settings.                                    primary API for managing all aspects of
     Uri:Immutable URI reference.                 Wi-Fi connectivity.
                                                  WifiManager.WifiLock: Allows an
                                                   application to keep the Wi-Fi radio
                                                   awake.
Network support by Android
                         android.telephony.gsm
   Other packages
                          Provides  APIs for utilizing
     javax.net            GSM-specific telephony
                           features, such as
     java.net             text/data/PDU SMS messages.
                           more...
     org.apache.http
                         Classes
                          GsmCellLocation:     Represents
                           the cell location on a GSM
                           phone.
                          SmsManager: Manages SMS
                           operations such as sending
                           data, text, and pdu SMS
                           messages.
                          SmsMessage: A Short
                           Message Service message.
Wireless Sensor
Networks
What is a Wireless Sensor
Network?
   Wireless Sensor Node =
    Sensor + Actuator + ADC +
    Microprocessor + Powering
    Unit + Communication Unit
    (RF Transceiver)
                                       GPS Sensor Node
   An ad hoc network of self-
    powered and self-configuring
    sensor nodes for collectively
    sensing environmental data
    and performing data
    aggregation and actuation
    functions reliably, efficiently,
    and accurately.
Limitations of Wireless Sensors
   Wireless sensor nodes have many
    limitations:
     Modest    processing power – 8 MHz
     Very little storage – a few hundred kilobits
     Short communication range – consumes a lot
      of power
     Small form factor – several mm3
     Minimal energy – constrains protocols
       Batteries have a finite lifetime
       Passive devices provide little energy
Some Sample Applications
   Industrial and Commercial Uses
              Tracking – RFID
     Inventory
     Automated Machinery Monitoring
   Smart Home or Smart Office
     EnergyConservation
     Automated Lighting
   Military Surveillance and Troop Support
     Chemicalor Biological Weapons Detection
     Enemy Troop Tracking
   Traffic Management and Monitoring
Sensor-Based Visual Prostheses




   Retinal Implant   Cortical Implant
Typical Sensor Node Features
    A sensor node has:
      Sensing    Material
         Physical – Magnetic, Light, Sound
         Chemical – CO, Chemical Weapons

         Biological – Bacteria, Viruses, Proteins

      Integrated   Circuitry (VLSI)
           A-to-D converter from sensor to circuitry
      Packagingfor environmental safety
      Power Supply
         Passive – Solar, Vibration
         Active – Battery power, RF Inductance
Traffic Management &
Monitoring
                                 Future cars could use
                                  wireless sensors to:
                                   Handle Accidents
                                   Handle   Thefts




  Sensors embedded
  in the roads to:
     –Monitor traffic flows
     –Provide real-time
     route updates
 Ayushman*: A Pervasive Healthcare System
 * Sanskrit for long life

                                           Environmental
• Project @ IMPACT Lab,                    Sensors (Temperature etc)

  Arizona State University
                                                                                                                           Internet
                                                                            Stargate
• To provide a dependable,                                                  Gateway

  non-intrusive, secure, real-
  time automated health                                                                External Gateway

  monitoring.                                                                                             Central Server
                                      Medical Sensors
                                      (EKG, BP) controlled                                                                       Medical
                                      By Mica2 motes                                                                             Professional
• Should be scalable and
  flexible enough to be used
  in diverse scenarios from
  home based monitoring to                                   Body Based       Home/Ward Based        Medical Facility Based
  disaster relief, with minimal                              Intelligence     Intelligence           Intelligence

  customization.                                                                       Vision
  • To provide a realistic environment (test-bed) for testing communication
    protocols and systems for medical applications.
           K. Venkatasubramanian, G. Deng, T. Mukherjee, J. Quintero, V Annamalai and S. K. S. Gupta,
           "Ayushman: A Wireless Sensor Network Based Health Monitoring Infrastructure and
           Testbed", In Proc. of IEEE DCOSS June 2005
Ayushman: Current Setup
                                           database


                                                                    RS232
                                               Base                            Oximeter
                                               Station
                                  802.11
                                                          ZigBee


                 Central Server
                                                                          Blood Pressure
                                                                   Environmental
                                                                   Data (accelerometer,
    Internet                                                       Temperature, humidity,
                                                                   Light)
                                      Body Area Network


                      Properties
                      •   Hardware and software based architecture
                      •   Multi-tiered organization
                      •   Real-time, continuous data collection
                      •   Query support (past, current data)
                      •   Remote monitoring capability through the Internet
                      •   Simple alarm generation
Remote Clients
Enabling Technologies


               Iris


                            MicaZ
 Imote2
              Mica2Dot              +
      Mica2              TelosB



Commercially available sensor       Open source OS with support for ad
          boards                             hoc networking
    Phone to WSN Interface
   Design Principles:
       To minimize the changes to the existing WSN
        architecture (required to maintain backward
        compatibility with previous apps.)


       To leverage COTS hardware and existing
        software solutions (to minimize the
        development time).


   Issues to address:
       Phone to sensors interface

       Data handling on the cell phone
                                                       Monitoring and
                                                      Control Software
  Context Generation                               Medical Context
                                                   • Is an aggregate of 4 base contexts.
                                                   • Each physiological event has to be
                   Physiological                     characterized by all 4 base contexts for
                 (EKG, Perspiration,
                    Heart Rate)                      accurate understanding of patient’s
                                                      health.
                                                   • A contextual template can be created for
                                                     specific physiological events for future
                      Spatial
                                                     reference.
                 (Home, Gym, Office,
                   Hospital, Park)



                                        Context                        Aggregate
                                       Processor    Knowledge
                      Temporal
                                                                       Context
Sensor Network    (Morning, Evening,
                        Night)


                                                      Challenges
                                                      • How to determine the
                    Environmental
                                                       aggregate medical context
                   (Humidity, Temp)                    from the four base contexts?
                                                      • How to create a contextual
                                                       template for a patient?

                      Base Context
Security in Pervasive Healthcare
Context
   Patient data is transmitted wirelessly by low capability sensors
       Patient data is therefore easy to eavesdrop on
       Security schemes utilized may not be strong enough for cryptanalysis


   Patient data is stored in electronic format and is available through the Internet
       Makes it easy to access from around the world and easy to copy
       Data can be moved across administrative boundaries easily bypassing legal issues.

   Electronic health records store more and more sensitive information such as psych reports and HIV status

   Preserving patient’s privacy is a legal requirement (HIPAA)

Excruciating Factors
   Wireless connectivity is always on

   No clear understanding of:
       Trusted parties
       Security policies for medical environment

   Devices are heterogeneous with limited capabilities

   Traditional schemes too expensive for long term usage
    Security Related Issues
New Attacks                                              Technology
                                                                 Efficient cryptographic primitives
   Fake emergency warnings.
                                                                     Cheaper encryption, hash functions
   Legitimate emergency warnings                                Better sensor hardware design
    prevented from being reported in times.                          Cheap, tamper-resistant sensor
                                                                      hardware
   Unnecessary communication by                                 Better communication protocol design
    malicious entity with sensors can cause:                     Better techniques for controlling
                                                                  access to patient EHR
           Battery power depletion
           Tissue heating
                                                         Legislation
Requirements                                              Health Information Privacy and
    Integrity - Ensure that information is accurate,        Accountability Act (HIPAA)
     complete, and has not been altered in any way.              Passed in 1995
    Confidentiality - Ensure that information is only           Provides necessary privacy protection for
                                                                  health data
     disclosed to those who are authorized to see it.
                                                                 Developed in response to public concern
    Authentication – Ensure correctness of claimed               over abuse of privacy in health
     identity.                                                    information
    Authorization – Ensure permissions granted for              Establishes categories of health
                                                                  information which may be used or
     actions performed by entity.                                 disclosed
Energy Efficiency
Need                                  Solutions
 Sensors have very small
  battery source.                   Solar Energy        Better Battery
 Sensors need to be active for
  long time durations.
 For implantable sensors, it is
  not possible to replace battery
  at short intervals.

Challenge
 Battery power not increasing at
  same rate as processing
  power.
 Small size (hence less energy)
  of the batteries in sensors.
                                      Vibration
                                                   Body Thermal Power
Challenges and
Solution Approaches
Constrained resources: power
   Current technology
     Battery-powered devices
     1150 mAh (G1), 1400 mAh (iPhone), 1300
      mAh (Blackberry)
   Future technology
     Replenishable   energy storage
   Until then:
     Power-save   modes: wireless, screen etc.
Constrained resources:
connectivity
   Current technologies
     WiFi, WiMAX, Bluetooth, 3G
     Possibly no coverage, intermittent interruptions,
      limited(?) bandwidth
   Future technology
         wireless, interchange between technologies,
     Still
      more availability & bandwidth
   Approaches:
     Disconnections:use of local cache, buffering
     Adaptive encoding and compression
Constrained resources:
data consistency
   Direct effect of connectivity challenge
   Approaches:
     Disallow      offline writes, use online-only mode
      (NFS)
          System may become unresponsive during
           disconnections
     Distributed/Network         file system (Coda, Andrew)
          Requires heavy clients with large cache
               May be too heavy for certain devices
Constrained resources:
computation
   Current technologies
     Blackberry3G: Intel PXA901 312 MHz, 64 MB flash +
      16 MB SDRAM
     iPhone 3G: ARM 1176, 400/620 MHz 128 MB DRAM
     G1: Qualcomm MSM7201A, 528MHz, 192 MB DDR
      SDRAM + 256 MB Flash
   Future technology
     Limitedby wattage and available energy
     Always behind desktop CPUs
   Approaches:
     Lightweight,   streamlined O/S and applications
Constrained resources:
storage
   Current technologies
     iPhone 3G: Flash 16GB
     G1: MicroSD (up to 16GB)

   Future technology
     Solid   state hard drives
   Approaches:
     Storeddata compression, selective data,
      remote storage
Constrained resources:
user interface methods
   Current technologies
     Display size: ~5ʺ
     Constrained or no   keyboard
   Future technologies
     There may be a convergence of input methods (e.g.
      touch screens, voice recognition)
     presentation will continue to be different (audiovisual
      capabilities and sizes)
   Solution approaches
     Adjust content to match size of display (e.g. favor
      close-ups)
     Use assistive methods (e.g. auto-completion,
      templates)
Groups
Groups
   Group1                         Group 4
     Logsdon, Brandon               Krolikowski, Tomasz
     Boyd, Jeffrey Michael          Randolph, April A
     Yao, Robert James Y (?)        Gutierrez, Pedro U


   Group 2                        Group 5
       Olsen, Samuel H                Chulick, Ryan Owen
       Perambalam, Sivaguru           Hursh, Nathaniel P
       Viswanathan, Lakshmie          Trujillo, Miguel Zeniff
        Narayan
                                   Group 6
   Group 3                            Deshpande, Koustubha Achyut
     Bootz, Bradley Justin            Neelakandan, Vikram
     Douglas, Robert Wayne            Abbasi, Zahra
     Freed, Natalie Anne
                                   Group 7
                                       Banerjee, Ayan
                                       Thangavel, Karthik

				
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