Context refers to information that can characterize an entity's situation, such as a user's location, identity, activity, time, nearby objects and people. Context-aware computing uses sensors to automatically collect context and adapt applications and services to the user's context. There is a need for context-aware computing because computers lack the implicit contextual cues that humans use in communication. Context-aware applications can make interactions between humans and computers more natural by tailoring information and services to the user's changing context.

1. CONTEXT AWARE COMPUTING
By Swati A. Sonawane
M.E. (SSA)

2. Overview
Context
Definition
Categorization
Characteristics
Context Awareness
Context Aware Computing
Need For Context Aware (CA) Computing
Context-Aware Application Development
Approach
Categorization of features
Model / Framework Properties
Example
Issues and Challenges
References

3. Who is “ANNA” ??

4. Google Search Results
2-3 months before :
First search result for WHY ?
Current Search Complex Searching
“ANNA” Shows : First Algorithms Takes
Search Result as Following In
Anna Kournikova
Consideration
(Famous Tennis Anna Hajare.
Player / Model ) 1. IP based Location
2. Current Activity on
Internet Searches
3. Page Ranking etc ..
“ CONTEXT ”

5. Context
The word context is derived from the Latin “contextus”,
which means “connection of words, coherence,” and
from contexere “to weave together.”
No clear boundary divides what is and is not context.
Most interesting kinds of context are those that humans do
not explicitly provide.
With advances in sensing and automated means of
perceiving the physical environment, we can automatically
collect much more implicit context.

6. Context ( cont…)
SOME OTHER DEFINITIONS ….
In the work that first introduces the term context-aware, Schilit and Theimer
(1994) refer to context as location, identities of nearby people and objects, and
changes to those objects.
In a similar definition, Brown et al. (1997) define context as location, identities of
the people around the user, the time of day, season, temperature, etc.
Ryan et al. (1998) define context as the user’s location, environment, identity, and
time.
Dey (1998) enumerated context as the user’s emotional state,focus of attention,
location and orientation, date and time, and objects and people in the user’s
environment.
Finally, Pascoe (1998) defines context to be the subset of physical and conceptual
states of interest to a particular entity.
Context defines some rules of inter-relationship of features in processing any
entities as a binding clause.

7. Context ( cont…)
FINAL INTERPRETATION
“ Context is any information that can be used to characterize the situation of
an entity. An entity is a person, place, or object that is considered relevant
to the interaction between a user and an application, including the user
and the application themselves.”
-- Dey and Abowd, 2000
Context: the interrelated conditions in which something exists or occurs.
-- Merriam-Webster Dictionary
Specifically, in context-aware computing, we use the term context to refer
to the circumstances under which a specific computational program is
being executed, such as the current occupation of the user while some
device is being used, or the current state of the environment in terms of
which it can be fully understood and asserted

8. Examples of Context
TIME
LIGHT LOCATION
IDENTITY
SOCIAL
PRESSURE

9. Context Helps us to do things better
Context influences how we perceive information.
Context enables us to manage the vast amount of
information that surrounds us.
Context guides us through the information surrounding us.
Context allows to discriminate “what is important” and
“what is not” .
Context helps us to adapt to our surroundings.

10. Context Categorization
Human factors
– information on the user (knowledge of habits, emotional state,
biophysiological conditions)
– the user’s social environment (co-location of others, social interaction,
group dynamics)
– and the user’s tasks (spontaneous activity, engaged tasks, general
goals).
Physical Context
– Active context: influences the behaviour of the application.
where active context-awareness autonomously changes the
application behavior according to the sensed information.
– Passive context: context that is relevant but not critical.
Passive context-awareness presents updated context or sensor
information to the user but lets the user decide how to change the
application behavior.

11. Context Categorization
Schilit, Adams, and Want (1994) attempted to define context by
specifying three categories of context:
Computing context: For example, network connectivity,
communication bandwidth,nearby resources like printers, displays;
User context: For example, user’s profile,location, emotional state,
people nearby,current activity;
Physical context: For example, lighting,noise level, traffic
conditions, temperature
Some of researchers consider TIME Context as another category.
(time of the day , month , year )

12. Context Categorization
Others….
Primary Context :
More important than others, e.g. location (where),
identity (who), time (when), and activity (what)
Secondary Context :
Which can derived from primary contraints, e.g. Distances,
Relationships

13. Characteristics of context
Context information exhibits a range of temporal
characteristics
Context information is imperfect
Context has many alternative representations
Context information is highly interrelated

14. Context Awareness
Computers can both sense, and react based on their environment.
Devices may have information about the circumstances under which they
are able to operate and based on rules, or an intelligent stimulus, react
accordingly.
Context aware devices may also try to make assumptions about the user's
current situation.
The term context-awareness in ubiquitous computing was introduced by
Schilit (1994).
Applications that use context, whether on a desktop or in a mobile or
ubiquitous computing environment, are called context-aware.

15. Context Awareness
Remember Past Events
Reminders for future events
Using Triggers
Sharing Experiences
Dey and Abowd (2000) define context awareness more generally with
the following statement:
A system is context-aware if it uses context to provide relevant
information and/or services to the user, where relevancy depends
on the user’s task.

16. Context Awareness
Thus context-awareness was more or less regarded as synonymous
with adaptivity.
Adaptivity thereby comprises principally:
Restricting the user interface to the relevant input possibilities and
relevant data;
Adapting dynamically to the user’s context how the information is
presented and how it can be accessed, for example, use of audio
output instead of visual output if the user is currently driving;
Automating actions for the user.

17. Context Aware Computing
Schilit, Adams, & Want (1994) defines “Context-aware
computing” as
“software that examines and reacts to an individual’s
changing context.”
Means “…aware of its user’s state and surroundings, and help
to adapt its behavior”

18. Need For Context Aware (CA) Computing
Human to Human
communication
Situational Past and future events,
information such as
facial expressions, The existence of other people in
the room
Emotions,
The process of building this
Voice tone shared understanding between
two people is called grounding .

19. Need For Context Aware (CA) Computing
Human and Computer
communication
Following Tasks Cannot be easily done by Computers :
Understanding and Interpreting our language
• We need to be very specific about giving commands
• OR asking for information
Cannot sense information about the current situation
• Sensing Facial expression
• Presence of other people near by.

20. Need For Context Aware (CA) Computing
Human and Computer
communication
Information is provided to computers, typically using a
keyboard and mouse
As a result , Producing an effect contrary to the promise of
transparency in Weiser’s vision of ubiquitous computing

21. Need For Context Aware (CA) Computing
Need of Context in Ubicomp Environment
Context, critically required in Ubicomp Environment .
Mobile computing and ubiquitous computing have given users the
expectation that they can access whatever information and services they
want, whenever they want, and wherever they are.
With computers being used in such a wide variety of situations,
interesting new problems arise, and the need for context is clear: users are
trying to obtain different information from the same services or systems in
different situations.
Context can be used to help determine what information or services to
make available or to bring to the forefront for users.

22. Need For Context Aware (CA) Computing
Input deficiency is resolved, by two basic approaches:
Improving the language that humans can use to interact with
Computers
Increasing the amount of situational information, or context, that is
made available to computers
Need for explicitness does exist in human–computer interactions,
because the computer does not share this implicit situational information
or context
The goal of context-aware computing is to use context as an implicit cue
to enrich the impoverished interaction from humans to computers, making
it easier to interact with computers.

23. Need For Context Aware (CA) Computing
Smart phones having great computing power.
Hi-Speed internet and wireless services.
Above two makes user’s context more dynamic.
With ubiquitous computing, users move throughout an environment and
interact with computer-enhanced objects within that environment.
This also allows them to have access to remote information and services
Our wearable system contains a radio link that connects the user to
computing resources and services from the Internet.
The use of context in mobile device is receiving increasing attention in
mobile and ubiquitous computing research.

24. Context Aware Applications
“A system is context-aware if it uses context to provide
relevant information and/or services to the user, where
relevancy depends on the user’s task.”
E.g. Smart Phones screen goes Brighter when exposed to light
( using photo sensors), And goes dimmer on low battery .
Some of the
context Aware
Apps For
Android

25. Context Aware Applications
Architecture
Context Input
Explicit Context Aware Explicit
Input Application Output

26. Context Aware Applications
Context-aware applications look at the
– who’s,
– where’s,
– when’s, and
– what’s (i.e., what activities are occurring)
of entities and use this information to determine why a situation is
occurring.
An application does not actually determine why a situation is occurring,
but the designer of the application does.
The designer uses incoming context to determine the user’s intent, or why
a situation is occurring, and uses this to encode some action in the
application that helps to satisfy this intent.

27. Categorization of features CA Applications
First provided by Schilit et al. (1994) and had two orthogonal
dimensions: whether the task is to obtain information or
to execute a command, and whether the task is executed
manually or automatically.
Proximate selection applications.
Automatic contextual applications.
Contextual command applications.
Context triggered actions.

28. Categorization of features CA Applications
Categorization By
Pascoe
• contextual sensing - detect and present to user
• context adaptation - execute or modify a service automatically
• contextual resource discovery - locate and exploit resources and services
• contextual augmentation (associating digital data with user’s context)
Dey:
• presentation of information/services to a user according to current
context
• automatic execution of a service when in a certain context
• tagging context to information for later retrieval

29. Categorization of features CA Applications
Two Major Benefits of Categorization of features
The first is that it further specifies the types of applications
that researchers provide support for.
The second benefit is that it describes the types of features
that developers should be thinking about when building
ContextAware applications.

30. Approach to context-aware application
development
To collect implicit contextual information through automated
means ( using Sensors , Camera etc .)
Make it easily available to a computer’s runtime
environment,
And let the application designer decide what information is
relevant and how to deal with it.

31. Properties of Context Aware “Model/Framework”
Adapt interfaces ( Context sensing and acquisition )
Increase the precision of information retrieval,
Tailor the set of application-relevant data ( Processing,
aggregation and reasoning of contextual data )
Context modeling, representation and storing,
Context-aware application adaptation,

32. Properties of Context Aware “Model/Framework”
Integration of context-awareness into service-oriented
architectures
Security and privacy of context data,
Discover services
2G , 3G or Wifi connect to best of available.
Make the user interaction implicit, or build smart
environments.

33. Example (Google Latitude)
Uses the following ways to locate exact position on Earth
– Global Positioning System
– Tower Signal INFO
– IP address, If wifi connnected .
– Digital Compass Signal To show the direction.
Context
– Location
– Time
It also shows your Friends location on map, if they are using same
application and sharing location

34. Example (Google Latitude)
Application Can be written
on top of this , like
location based alarm ,
near friend notifier.

35. Example (Bump)
Bump two phones together to share
– Photos
– contacts
– apps
Without knowing Email id / IP address.
Bump makes sharing with people as simple as
bumping two phones together.
Context Collected via
– Vibration/motion sensor
– Location detectors (for verification)
Time is most important as context.

36. Issues and Challenges
Errors Occurred because of wrong interpretation of
Context :
When the system does the wrong thing
– Auto-locking car doors
– Screen saver during presentation
– Microphone amplifying a whisper
In these examples, is the system or the user at fault?

37. Issues and Challenges
Challenges in Context-Aware Computing
– How to represent context internally? (Storage)
– Data structures and algorithms
– How frequently does the system need to be updated on
context changes?
– How often to poll? ( in case limited power )
– How often to change behavior?
– What sensors infrastructure, or sensors are necessary?
– What is the fallback condition?
– How to sense location information?

38. Issues and Challenges
• Issues to Consider when Building Context-Aware
Applications
– Context Is a Proxy for Human Intent
– Context Inferencing
• is the act of making sense of these input data from sensors and other
sources, to determine or infer the user’s situation.
– Context Ambiguity
– “Rules” versus “Machine Learning”
– Privacy
– Evaluation
– End User Issues
• Understanding of Application’s behavior
• How much control on application user should have

39. References
• Handbook of Research on Ubiquitous Computing
Technology for Real Time Enterprises
---Max Mahlhauser, Iryna Gurevych
• Ubiquitous Computing Fundamentals
---John Krumm
• Advances in Ubiquitous Computing Future
Paradigms and Directions
----Mostefaoui, Maamar,Giaglis

40. THANK YOU!!