Context-Aware Computing

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Context-AwareComputing

• CSE494/598 Mobile Health and Social Networking

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Context awarenessthe 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

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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
• Computing context connectivity, communication
  cost, bandwidth, nearby resources (printers,
  displays, PCs)
• User context user profile, location, nearby
  people, social situation, activity, mood
• Physical context temperature, lighting, noise,
  traffic conditions
• Temporal context (time of day, week, month,
  year)
• Context history can also be useful

• Another definition Abowd Mynatt
• Social context user identity and human partner
  identities
• Functional context what is being done, what
  needs to be done
• Location context where it is happening
• Temporal context when it is happening
• Motivation context why it is happening (purpose)

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Context (contd)
Sensor data

• Other classifications of context
• Low-level vs High-level context
• Active vs Passive context
• Putting it all together
• Gather low-level context
• Process and generate high-level context
• Separate active from passive context
• adjust

Low-levelcontext
motivational
social
user
location
computing
temporal
high-levelcontext
Context processing
activecontext
passivecontext
Context-aware application
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Context-Aware Application Design

• How to take advantage of this context
  information?
• Schilits classification of CA applications
• Proximate selection
• closely related objects actions are
  emphasized/made easier to choose
• Automatic contextual reconfiguration
  adding/removing components or changing
  relationships between components based on context
• Switch to a different operation mode
• Enable or disable functionality
• Context-triggered actions rules to specify how
  the system should adapt
• Contextual information and commands produce
  different results according to the context in
  which they are issued
• Narrow-down the output to the user using the
  context
• Broaden the output to the user using the context
• Is this classification fundamental/inclusive?

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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

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Location-Based Services

• Requirements
• Geocoder (convert street addresses to latitude /
  longitude), Reverse geocoder
• Address Helper (many addresses inaccurate or
  incomplete)
• Map data
• Data Repository
• Points of Interest data e.g. pubs, restaurants,
  cinemas
• Business Directory (doctors, plumbers etc by
  location)
• Location-based Inventory

• Issues
• Content providers Telcos jealously guarding own
  domain
• Proprietary software e.g. Windows Live
• Price of map data varies widely, very expensive
  in some countries e.g. Australia
• Integration into customers web sites (APIs)
• Cognitive Routing routing / directions using
  terminology relevant to user (e.g. resident c/f
  tourist)

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LBS Navigation

• Basic form of Location-based services
• Map service (Geocoder)
• You are here service
• Route discovery and generation of directions
• Add-ons
• Voice-activated
• Adjust route to traffic and accident conditions
• Integration with calendar and address book
• Notify target partner of arrival

• android.location
• Classes defining Android location-based and
  related services.
• Interfaces
• LocationListener Used for receiving
  notifications from the LocationManager when the
  location has changed.
• Classes
• Address represents an Address, i.e, a set of
  Strings describing a location.
• Geocoder handles geocoding and 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.

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LBS Social NetworkingBuddyFinder 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 GPSmap service
• Extension of LBSNavigation?

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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

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In-class exercise, feedback
Table 1 Table 2 Table 3 Table 4 Table 5 Table 6
Application Google maps Secure gateway Hitch-hikers Party Management Mood-based music player Meeting scheduler (calendar and email)
Context Your location Security gateway availability Location destination Location Partners Neighbors mood Situtation Mood Current time, meeting time
Adaptivity Center/zoon to your location Pre-authorized access Matching hitch-hikers to drivers Order list Playlist Adjust music and volume Notify of delays
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Wireless Communicationsand Networks
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Wireless Networks
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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 (lt0.1) 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)

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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
  (lt70MBps), metropolitan coverage (1 to 30 miles)
• Packet Data Networks
• ARDIS
• RAM
• Cellular Digital Packet Data (CDPD)
• Private Networks
• Public safety, UPS.

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Wireless Local Area Network

• Data services IP packets
• Coverage Area Offices, buildings, campuses
• Roaming Within deployed systems
• Internet access via LAN.
• Type of services Data at near LAN speed.

• Variant Connectivity
• Low bandwidth and reliability
• Frequent disconnections
• predictable or sudden
• Asymmetric Communication
• Broadcast medium
• Monetarily expensive
• Charges per connection or per message/packet

• Connectivity may be weak, intermittent and
  expensive

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Network support by Android

• android.net
• Classes that help with network access, beyond the
  normal java.net. APIs. more...
• Classes
• ConnectivityManager answers queries about the
  state of network connectivity.
• DhcpInfo A simple object for retrieving the
  results of a DHCP request.
• MailTo MailTo URL parses a mailto scheme URL and
  then can be queried for the parsed parameters.
• NetworkInfo Describes the status of a network
  interface of a given type
• Proxy A convenience class for accessing the user
  and default proxy settings.
• UriImmutable URI reference.

• android.net.wifi
• Provides classes to manage Wi-Fi functionality on
  the device. more...
• Classes
• ScanResult Describes information about a
  detected access point.
• WifiConfiguration A class representing a
  configured Wi-Fi network, including the security
  configuration.
• WifiConfiguration.Protocol Recognized security
  protocols.
• WifiConfiguration.Status Possible status of a
  network configuration.
• WifiInfo Describes the state of any Wifi
  connection that is active or is in the process of
  being set up.
• WifiManager This class provides the primary API
  for managing all aspects of Wi-Fi connectivity.
• WifiManager.WifiLock Allows an application to
  keep the Wi-Fi radio awake.

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Network support by Android

• Other packages
• javax.net
• java.net
• org.apache.http

• android.telephony.gsm
• Provides APIs for utilizing GSM-specific
  telephony features, such as text/data/PDU SMS
  messages. more...
• 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.

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Wireless Sensor Networks
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What is a Wireless Sensor Network?

• Wireless Sensor Node Sensor Actuator ADC
  Microprocessor Powering Unit Communication
  Unit (RF Transceiver)
• 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.

GPS Sensor Node
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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

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Some Sample Applications

• Industrial and Commercial Uses
• Inventory Tracking RFID
• Automated Machinery Monitoring
• Smart Home or Smart Office
• Energy Conservation
• Automated Lighting
• Military Surveillance and Troop Support
• Chemical or Biological Weapons Detection
• Enemy Troop Tracking
• Traffic Management and Monitoring

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Sensor-Based Visual Prostheses
Retinal Implant
Cortical Implant
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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
• Packaging for environmental safety
• Power Supply
• Passive Solar, Vibration
• Active Battery power, RF Inductance

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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

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Ayushman A Pervasive Healthcare System
Sanskrit for long life
Environmental Sensors (Temperature etc)

• Project _at_ IMPACT Lab, Arizona State University
• To provide a dependable, non-intrusive, secure,
  real-time automated health monitoring.
• Should be scalable and flexible enough to be used
  in diverse scenarios from home based monitoring
  to disaster relief, with minimal customization.

Internet
Stargate Gateway
External Gateway
Central Server
Medical Sensors (EKG, BP) controlled By Mica2
motes
Medical Professional
Home/Ward Based Intelligence
Body Based Intelligence
Medical Facility Based Intelligence
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
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Ayushman Current Setup
database
RS232
Oximeter
Base Station
802.11
ZigBee
Central Server
Blood Pressure
Environmental Data (accelerometer, Temperature,
humidity, Light)
Bluetooth
Internet
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
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Enabling Technologies

Commercially available sensor boards
Open source OS with support for ad hoc networking
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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
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Context Generation

• Medical Context
• Is an aggregate of 4 base contexts.
• Each physiological event has to be characterized
  by all 4 base contexts for accurate
  understanding of patients
• health.
• A contextual template can be created for
  specific physiological events for future
  reference.

Physiological (EKG, Perspiration, Heart Rate)
Context Processor
Spatial (Home, Gym, Office, Hospital, Park)
Knowledge
Aggregate Context
Temporal (Morning, Evening, Night)
Sensor Network

• Challenges
• How to determine the aggregate medical context
  from the four base contexts?
• How to create a contextual template for a
  patient?

Environmental (Humidity, Temp)
Base Context
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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 patients privacy is a legal
  requirement (HIPAA)
• Excruciating Factors
• Wireless connectivity is always on
• No clear understanding of

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Security Related Issues

• New Attacks
• Fake emergency warnings.
• Legitimate emergency warnings prevented from
  being reported in times.
• Unnecessary communication by malicious entity
  with sensors can cause
• Battery power depletion
• Tissue heating

• Technology
• Efficient cryptographic primitives
• Cheaper encryption, hash functions
• Better sensor hardware design
• Cheap, tamper-resistant sensor hardware
• Better communication protocol design
• Better techniques for controlling access to
  patient EHR

• Legislation
• Health Information Privacy and Accountability Act
  (HIPAA)
• Passed in 1995
• Provides necessary privacy protection for health
  data
• Developed in response to public concern over
  abuse of privacy in health information
• Establishes categories of health information
  which may be used or disclosed

• Requirements
• Integrity - Ensure that information is accurate,
  complete, and has not been altered in any way.
• Confidentiality - Ensure that information is only
  disclosed to those who are authorized to see it.
• Authentication Ensure correctness of claimed
  identity.
• Authorization Ensure permissions granted for
  actions performed by entity.

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Energy Efficiency
Solutions

• Need
• Sensors have very small battery source.
• 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.

Better Battery
Solar Energy
Vibration
Body Thermal Power
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Challenges and Solution Approaches
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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.

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Constrained resources connectivity

• Current technologies
• WiFi, WiMAX, Bluetooth, 3G
• Possibly no coverage, intermittent interruptions,
  limited(?) bandwidth
• Future technology
• Still wireless, interchange between technologies,
  more availability bandwidth
• Approaches
• Disconnections use of local cache, buffering
• Adaptive encoding and compression

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Constrained resourcesdata 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

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Constrained resources computation

• Current technologies
• Blackberry 3G 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
• Limited by wattage and available energy
• Always behind desktop CPUs
• Approaches
• Lightweight, streamlined O/S and applications

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Constrained resourcesstorage

• Current technologies
• iPhone 3G Flash 16GB
• G1 MicroSD (up to 16GB)
• Future technology
• Solid state hard drives
• Approaches
• Stored data compression, selective data, remote
  storage

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Constrained resourcesuser interface methods

• Current technologies
• Display size 5"
• 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)

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Groups
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Groups

• Group1
• Logsdon, Brandon
• Boyd, Jeffrey Michael
• Yao, Robert James Y (?)
• Group 2
• Olsen, Samuel H
• Perambalam, Sivaguru
• Viswanathan, Lakshmie Narayan
• Group 3
• Bootz, Bradley Justin
• Douglas, Robert Wayne
• Freed, Natalie Anne

• Group 4
• Krolikowski, Tomasz
• Randolph, April A
• Gutierrez, Pedro U
• Group 5
• Chulick, Ryan Owen
• Hursh, Nathaniel P
• Trujillo, Miguel Zeniff
• Group 6
• Deshpande, Koustubha Achyut
• Neelakandan, Vikram
• Abbasi, Zahra
• Group 7
• Banerjee, Ayan
• Thangavel, Karthik