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  • Commercially available sensor boards and “out of the box” ad hoc networking using TinyOS allow the researchers for rapid sensor network deployments.
  • Basic Idea: to use a phone to monitor/control an ad-hoc network of sensor nodes. What is the easiest way to connect a phone to a WSN ensuring short development time and compatibility with existing solutions?

Transcript

  • 1. Context-Aware Computing CSE494/598 Mobile Health and Social Networking
  • 2. 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
  • 3. Defining Context
    • 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)
    • 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”
  • 4. Context (cont’d)
    • 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
    social temporal motivational location user Sensor data computing Low-level context Context processing high-level context Context-aware application active context passive context
  • 5. Context-Aware Application Design
    • How to take advantage of this context information?
    • Schilit’s 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?
  • 6. 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
  • 7. 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 customer’s web sites (API’s)
      • Cognitive Routing – routing / directions using terminology relevant to user (e.g. resident c/f tourist)
  • 8. 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.
  • 9. 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?
  • 10. 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
  • 11. 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
    • Neighbor’s 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
  • 12. Wireless Communications and Networks
  • 13. Wireless Networks 10 kbps 100 kbps 1Mbps 10Mbps 100Mbps 1 m 10 m 100 m 1 km 10 km 100 km WPAN (ZigBee, Bluetooth) 2G 3G WLAN (WiFi) WMAN (WiMAX) Satellite
  • 14. 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)
  • 15. 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.
  • 16. 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
  • 17. 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.
      • Uri :Immutable 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.
  • 18. 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.
  • 19. Wireless Sensor Networks
  • 20. 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
  • 21. 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 mm 3
      • Minimal energy – constrains protocols
        • Batteries have a finite lifetime
        • Passive devices provide little energy
  • 22. 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
  • 23. Sensor-Based Visual Prostheses Retinal Implant Cortical Implant
  • 24. 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
  • 25. 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
  • 26. Ayus hman *: A Pervasive Healthcare System
    • Project @ 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.
    Vision * Sanskrit for long life
    • 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, &quot;Ayushman: A Wireless Sensor Network Based Health Monitoring Infrastructure and Testbed &quot;, In Proc. of IEEE DCOSS June 2005 Environmental Sensors (Temperature etc) Medical Sensors (EKG, BP) controlled By Mica2 motes Body Based Intelligence Home/Ward Based Intelligence External Gateway Central Server Medical Facility Based Intelligence Medical Professional Internet Stargate Gateway
  • 27. Ayus hman : Current Setup Internet Environmental Data (accelerometer, Temperature, humidity, Light) Blood Pressure Oximeter ZigBee 802.11 Remote Clients Central Server Base Station Body Area Network RS232
    • 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
    database Bluetooth
  • 28. Enabling Technologies Commercially available sensor boards Open source OS with support for ad hoc networking + TOS v.1.x-2.0 Ad-hoc Networking Mica2 TelosB Imote2 Mica2Dot Iris MicaZ
  • 29. 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
  • 30. Context Generation Physiological (EKG, Perspiration, Heart Rate) Environmental (Humidity, Temp) Spatial (Home, Gym, Office, Hospital, Park) Temporal (Morning, Evening, Night) Sensor Network Knowledge Context Processor
    • 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 patient’s
    • health.
    • A contextual template can be created for specific physiological events for future reference.
    • Challenges
    • How to determine the aggregate medical context from the four base contexts?
    • How to create a contextual template for a patient?
    Aggregate Context Base Context
  • 31. 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
  • 32. 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.
  • 33. Energy Efficiency
    • 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.
    Solutions Solar Energy Better Battery Vibration Body Thermal Power
  • 34. Challenges and Solution Approaches
  • 35. 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.
  • 36. 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
  • 37. 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
  • 38. 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
  • 39. Constrained resources: storage
    • 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
  • 40. 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)
  • 41. Groups
  • 42. 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