1. Context-Aware Communication for People
Telephone amazing technology has helped communication from the 1870s
• could ring at most inappropriate and inconvenient times and be a source of
annoyance
• the callee does not have a choice and is forced to hear the ringing by the
caller, even if the callee does not answer the phone.
Making the phone not ring, 2005, H. Schulzrinne, Columbia Univ.
• presentation at the Internet2 Spring Meeting
Context-aware communication
• Make the phone not ring except in an appropriate manner Evolution of VoIP
• The Phone rings at the callee situations
PRID : Rich Presence ID
automatically derived from
sensors: physical presence, movement
electronic activity: calendars
Provide watchers with better information about
the what, where, how of presentities
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2. 1. Routing
Routing : Messages or voice calls can be routed to the appropriate destination
• The phone in the right room can ring by call forwarding :
who they are with, where they are, what they are doing, what the time it is
• Augmenting device-mediated communication with context information enrich
user interaction.
Architectural Considerations for Scalable, Secure, Mobile Computing with Location
Information, 1994, Mike Spreitzerm Xerox Palo Alto
Ubiquitous Message Delivery at Xerox PARC (UMD, 1994)
• An autonomous system for both sensing and communication acts
• User location - active badges, keyboard input activity, and explicit commands
• Text delivered “at the soonest acceptable time via the most appropriate terminal
near the recipient”, waited for a suitable situation or terminal to be available
• User agent process : User location and the user’s policy regarding message
delivery were maintained
• Terminal agents : manage the policy of outputting messages on terminals
• No user-oriented heuristics for deciding acceptable times and appropriate
terminals
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3. 2. Addressing
Addressing : contextually appropriate people (mailing lists and shared spaces)
• Entities can be addressed based on their context instead of their unique
identifier or names
A Conceptual Framework and a Toolkit for Supporting the Rapid Prototyping of
Context-Aware Applications, 2001, Dey, Georgia Tec
The Context-Aware Mailing List
• Dynamic distribution list is used to deliver email messages to members of a
research group who are currently in the building
• Addressing email-style communication to a group of people who are selected
by their location.
• Context-aware mailing list built with the
Context Toolkit
Architecture diagrams for
the In/Out Board and
Context-Aware Mailing list
Applications
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4. 3. Messaging
Messaging : contextual reminder/messaging
• By knowing the situation of the receiver or addressee,
the right message can be delivered at the right time and in the right form,
be it a reminder message or an incoming e-mail
Hanging Messages – using Context-Enhanced messages for just-In-Time
communication, 2001, Chang and Maes, MIT
What is a hanging message?
• Context-enhances message for just-in-time communication
• A message which is delivered to a recipient at a specific place and time
• Envision the message as “hanging” in a certain location, waiting for the recipient
• Messages are context enhanced for better filtering
Mobile wireless device agent : Located an on each user's device
• make use of existing context to filter incoming communications.
• A user should never receive any unsolicited or irrelevant message
Filtering mechanisms :
 hierarchical categorization for messages
 user profiling by rules
 multiple location-based operational modes for each user.
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5. 4. Providing Awareness of callee
Providing awareness of callee or receiver
• One can determine if the individual is available to talk by presence awareness
• Presence awareness is similar to the idea of status in Instant Messenger systems
Context-aware communication with Live Contacts, 2004, G. Henriter Hofte
Live Contacts system (running on pocket PC phones, PC)
Presence information of listed contacts,
• current Messenger status (e.g., busy, online, away, on-the-phone, etc.)
• current calendar information (e.g., work and non-work times, appointments,…)
• last-known location information (e.g., at work, at home, on move, or unknown)
One can initiate contact (via telephone call, SMS, IM, or e-mail)
or ask to be reminded to make contact at a nominated future time.
Live Contact servers : A client–server architecture - querying for updates on contacts
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6. 5. Screening
Screening : establishing communication under appropriate conditions
• Filtering or redirecting calls based on the situation of the receiver combined with
the previous application types
• Inform the caller of the callee’s situation , and takes action automatically on
perceiving that the callee is unavailable
Ex) In a meeting, then the phone can be put in a certain mode, virtually filtering the
call
Calls.calm : callee specifies the extent of a caller’s access to situation information and
communication channels in a database of relationships
Uses Web phones to mediate communication with subscribers.
A person selects who to call, and he is greeted by the callees, contact page contextualized and
customized for the caller; if the caller is unknown, (c) a generic page.
For trusted callers, Calls.Calm reveals status, messages, and a list of preferred communication
channels.
The system supports negotiating a time to make a voice call by an exchange of short text
messages
The aforementioned application types may be combined in a specific application
Ex) Route messages using context as well as filter appropriate messages
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7. Call Services
Applying a Disciplined Approach to the Development of a Context-Aware
Communication Application, 2005, Ted McFadden, Australia
Context Information :
location , the status of the user,
available communication mode (e.g.,
voice, text, or video),
device battery power
Context Modeling Language (CML) :
represent the context representation
for context-communication application
ECA (Event, Condition, Action) model
the precondition in this case is always true,
and the action is to re-evaluate preferences
for the call of concern
Process the ‗Locate‘ messages
1. Context Manager is queried to discover
devices near the user
2. devices are rated against the FinalEval
preference
3. If any device gets an oblige score,
it is selected for use.
4. The SIP address for the device selected at
step 3 is determined from the “has address”
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8. Call Services
Context fact model for the communication application
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9. Application Types
Application types: addressing & context-aware commands
Ex) “when the 8 p.m. news is finished and if no one is watching, turn off
the television next to the chair John is sitting in.”
addressing : to TV by the context
command : “turn off” performed in the right context
Context ensures that commands are delivered in the right way and at the
right time to appliances.
Sensing/thinking/acting subsystems are studied previously.
Command Interpreter Determine the Sensing Reasoning Action
attribute
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10. Smart Space
Smart space : it can intercept and understand user commands
 Context-aware command processor : execute commands issued by a speaker
- interprets the user’s commands, translates it into an operation on a device,
- and invokes the operation on the device
 Query sensors & devices whether a command has been successfully completed
 Server : continuously listens for user commands and has access to devices
 Devices have an API or a Web service-like interface for invoking the operations
UPnP Design by Example, 2003, Jeronimo, Intel
UPnP(Universal Plug & Play) for future devices.
 Interface to devices to communicate with or make use of the device
 Action invoking to a UPnP control point
Ex) 3 services for Super Toaster device
• Lifetime Statistics, Toaster Status, Toaster Control
http://www.jini.org/wiki/Category:Introduction_to_Jini
 Jini : SUN
• Provides a Java-based object model of devices
• Discovery, Join, look-up, and client uses service.
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11. Smart Space
Smart Space
Lamp
Command to
target devices
door
Query
Utterance W
TV Operation
Query
Sensors
Infra Structure : Determine the situation
such as which device ?
Sensing/Thinking/Action
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12. Context-Aware
Sensor networks
윤 용운
2010.11.18
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13. Context-Aware Sensors
A survey on sensor network, 2002, Akyldiz, Georgia
Life Patterns: structure from wearable sensors, 2002, Brian Patrick Clarkson MIT
Sensor Networks
• Numerous applications : from kinder garden to traffic management
• Understanding regularity in everyday life behavior (wearable sensors MIT)
• Life patterns are the reoccurring events in daily behavior, such as those
induced by the regular cycle of night and day, weekdays and weekends,
work and play, eating and sleeping
Researches : networking protocols, Hardware, Operating systems, Programming model
2 related topics for Sensors and Context-aware Computing
• Sensors are used to acquire context information
• Sensors themselves can be made to be aware of their own context
Context-Aware Sensors: Aware
Context Sensor
Information
Acquire
Sensor networks + Context-aware computing
• whose behavior can be changed in response to their current context,
• power-conserving actions depending주차 the situation the sensors are in.
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14. Context-Aware Sensors: The Concept
WSN : wireless sensor network
 a combination of low cost, low-power, multifunctional miniature sensor devices
consisting of sensing, data processing, and communicating components,
networked through wireless links between neighboring nodes
 Large number of sensor nodes are deployed over an area
 Mesh network : relay sensed information to base station
 Energy constraints of sensors
for Sensing/Computing/Networking
Idea of Context-aware sensors
• If sensors know more about their own context, then they could adapt their
behavior and function only when needed in the current circumstances
 they becomes more prudent for spending energy
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15. Architecture
Framework
• Setting of groups of sensors – provide context & send/receive
commands
• Several support services – provide communication between sensors and
the system
• Components to provide the core functionalities for context discovery &
use
the sensor nodes –
• Programming : nesC under TinyOS
• To interface with the sensors : Java 1.1 API is used for modules that
provide data collection, analysis, and communication between the motes
and the base station
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16. Architectural diagram
Architectural diagram showing the main components of the framework
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17. Frameworks
Sensor groups :
• Send sensor readings to communication server
• Receive sensor control commands from the “Context Trigger Engine” via
communication server.
Communication server:
Acts as a mediator between the base station and the sensors
and provides a unified protocol of communication for applications
• Parse raw data packets from the sensors into a format recognizable by App.
• Parse control messages from the application to the sensors
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18. Frameworks
Context locator service: Interpret the current context from the raw sensor readings
• If-else condition rules – decide whether certain context has been acquired
• Form secondary context by conjunctions of different primary context information
Lookup IF temp sensor < threshold,
Temp
Sensor Context locator Primary context is cold
Temp server
Sensor IF groups of temp sensors < threshold,
Context Secondary context is coldweatherContext
name
Context mining service: context discovered autonomously in the system
• User programmed rules - Static context discovery and dependent on designed
scenarios
• With this service,
• Context locator service would be sampling sensor data
• Context mining service would be discovering context
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19. Frameworks
Context trigger engine: determines the sensor operations triggered,
• using a combination of given context and sensor profiles
• Action macros : a command or a combination of actual commands sent to
sensors
Context,
Sensor group
Other context information (Ex: current
Request time,) about the system can be used.
Context
Context scheduler Put found action macro on the queue
Actions
Action macro to be scheduled for triggering.
Data store
Time-to-trigger The queue operates based on a time-
to-trigger parameter
Macro Decoder Decompose the macro into simpler
instructions to be sent to the listening
application running at a base station
operations
Action Action Interpreter Sensor ID
operation Sensor
DB profile
Sensor control
message
Sensor command
Context action data store: Relationship between context & its respective actions
• 1-to-1 mapping, mapping with interdefined relationship
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20. Context-Aware
Security
윤 용운
2010.11.25
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