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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
        • Classes that help with network access, beyond the normal* 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.
        • 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
        • 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