Transcript UbiCom Book Figures - Queen Mary University of London

UbiCom Book Slides
Chapter 7
Context-Aware Systems
(Part A: Contexts & the Context-Aware Lifecycle)
Stefan Poslad
http://www.eecs.qmul.ac.uk/people/stefan/ubicom
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Chapter 7: Overview
Chapter 7 focuses on:
• Internal system properties: context-awareness
• External interaction with any type of environment
– Focussing more on physical environment
– A lesser extent focussing on ICT environment
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Related Chapter Links
• Context-awareness of human environment (iHCI) and
person-awareness and user context acquisition (Chapter 5)
• Environment context acquisition: sensors (Chapter 6)
• Environment context control: controllers (Chapter 6)
• Event-based system models for context-awareness
(Chapter 3)
• Goal-based models & sequential environment models
(Chapter 8)
• Content adaptation for mobile terminals (Chapter 4)
• UI techniques adapted for use in small and large displays
discussed (Chapter 5)
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Chapter 7: Overview
The slides for this chapter are also expanded and split into
several parts in the full pack
• Part A: Contexts & the Context-Aware Lifecycle
• Part B: Context Adaptation Design
• Part C: Spatial Awareness 1
• Part C: Spatial Awareness 2
• Part E: Mobile Awareness
• Part F: Temporal Awareness & Composite Context
Awareness
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Lecture Outline
•
•
•
•
•
•
•
•
Types of Context and Context Properties 
Context Aware Life Cycle
Context Adaptation
Spatial-Awareness
Mobile User Context Awareness: Call Routing
Content Adaptation for Mobile Terminals
Temporal awareness
Composite Context Awareness
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Smart (Physical) Environments
Physical
Environment
Devices
CPI
Context-aware
Self-aware
Structure
Environment
Context Types
Single
Physical
Human
Timeaware
Personalisation
GIS
Location
Sensor
or Tag
Multiple
Sense
Heterogeneous
ICT
Single
Attribute
iHCI
Locationaware
Operation
Device
Display
Adapt
Homogeneous
Multiple
Attribute
Passive
Active
Life-Cycle
Content
adaptation
Acquire
User
Control
Present
Acquire
Env.
Mobile
aware
Manage
Process
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Context Aware System versus Sensorbased System
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Contexts
• A context represents the state or situation in the
environment of a system that affects that system’s
(application specific) behaviour
• There are many definitions of context
• There are several dimensions or properties to
characterise contexts
• There are many definitions of how to make systems
aware of changes in their context: context awareness
• Context-awareness is considered to be one of the
fundamental properties of UbiComp systems and is a
key property of smart environments.
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Defining Contexts: Concrete
In terms of membership of some set of contexts
• Location, identities of nearby people, objects and changes
to those objects
• Applications
• External environment: physical, human, virtual
– Awareness of internal (self) context may also be useful
•
What, who, where, when, how it is accessed and why,
context is useful (Morse et al. (2000)
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Context Types: By Application
• We can classify context-awareness in terms of types of
applications?
• Mobility context-aware
• Location aware
• Time aware
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Lecture Outline
•
•
•
•
•
•
•
•
Types of Context & Context Properties
Context Aware Life Cycle 
Context Adaptation
Spatial-Awareness
Mobile User Context Awareness: Call Routing
Content Adaptation for Mobile Terminals
Temporal awareness
Composite Context Awareness
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Life-cycle for Context Awareness
•
•
•
•
•
Capture Physical Context
Capture User Context
Context Processing
Adapt to Context
Manage contexts
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Display
User Context
Creation
Context Processing
& Adptation
Adapted
Non-adapted
Context
User Tasks
Context
Annotated Content
User – Env
Context
Mediation
Policies
User
Context
Application
Annotation
Environment (Env)
Context Creation
Abstraction
Context Filter
Adaptation
Env Context
Composition
Store /
Retrieve
Discovery Access Control
Context
Store
Configuration
Sensors
Events
Environment
Context
Control
Context
Discovery
Actuators
Access
Control
Context Management
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User Context Creation
• Acquisition of user context: this can be derived from user’s
application tasks
• Policy creation: created from user’s tasks to determine how
a user context is mediated by environment contexts
• Encapsulation and abstraction: of the user context
• Sharing the user context so that it can be distributed and
accessed.
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Environment Context Creation / Capture
• Acquisition:
• Encapsulation:
• Abstraction:
• Filtering:
• Sharing:
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Context Processing
N.B Context acquisition may involve some context preprocessing, here the focus is on context post-processing.
Context post-processing enables:
• Context-composition:
• Context Mediation:
• Context Adaptation:
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Context Composition: Motivation
Context composition may also be driven by the need to:
• Improve acquisition accuracy for the context
–
• Improve filtering and adaptation of content
• Composite contexts are in inherent an application
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Context Composition: Challenges
•
•
•
•
•
•
Handling heterogeneity of representation
Handling heterogeneity of meaning
Mediating and coordinating context aggregation
Ordering the adaptation to individual contexts
Different weightings for combining contexts
Handling uncertainty in combining contexts
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Context Composition, Heterogeneous
Contexts & Interoperability
Context-aware systems may depend on & combine:
• multiple representations for a single context
•
.
• multiple representations of multiple contexts
• Multiple representations determined independently by
different applications & users
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Context Composition, Heterogeneous
Contexts & Interoperability
• Determination of a proposed joint context for meeting
can be complex
–
• Challenge here: to harmonize or standardize annotation
so that they would be consistent used by all users.
• Security, e.g., access control could be useful in certain
applications to protect privacy or to limit access,
–
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Context Management
• Discovery: directory services enable context sources,
stores and users to be registered and discovered.
• Storage: of context data into some data resource, may
include
– …
• Sharing of environment and goal contexts
• Access control:
– .
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Lecture Outline
•
•
•
•
•
•
•
•
Types of Context and Context Properties
Context Aware Life Cycle
Context Adaptation 
Spatial-Awareness
Mobile User Context Awareness: Call Routing
Content Adaptation for Mobile Terminals
Temporal awareness
Composite Context Awareness
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Context Adaptation: Passive vs Active
• Passive context adaptation system
– Context is presented to users
– Context-based tagging (chapter 6)
– System is not active in terms of adapting
• Active context-adaptation system
– Adaptation to context performed by the UbiCom system, not human
users.
• Hybrid context adaptive system
– Human user guides or corrects the automatic adaptation
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Context Adaptation Models
Event-based Models (Chapter 3)
• Context-awareness links context producer to a contextconsumer or context-adapter
• EDA is also similar to a Reactive intelligent system
– See Chapter 8
• How do we limit the types of interest?
Goal-based Models
• Use a (planned) application or user goal to limit the set of
current contexts which are useful
• Relation of current context to goal context is
fundamental
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Context-aware Application: Location
(context) awareness
• Goal
context
• Current
context
• Context
Path
• Constraints
• Travel to the destination
location
• Current location
• Planned path from the current
to destination location
• Not to deviate too far from the
anticipated or planned position
context;
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Context-aware Application: Location
(context) awareness
Start Context
start
Move Forward
Planned Current Context
Move To Side
Context Deviation
Re-plan & Move forward
Goal Context
Planned Current Context
Move To Side
Context Deviation
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Context Aware Design Issues
•
•
•
•
•
•
•
Context Representation 
Use of Current versus Past Contexts
Context Determination
Static versus Dynamic CA
Active versus Passive Context Adaptation (done)
Heterogeneous Contexts & Interoperability
Context Composition
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Context Representations
•
•
•
•
•
•
What type of data structures should be used to model
contexts?
Key-Value pairs
Hierarchies / Markup Schemes, e.g., XML
Graphs
Object Oriented (o-o)
Logic Based: support reasoning about context
Strong Ontology
Which of these is best? Why?
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Use of Current Context vs. use of
Context History
• Simplest type of context-aware system
– Uses the current context, the current state, episodic, environment
– Operates in an environment that is fully observed and deterministic
• But context history can also be used
• See Chapter 8 for more in-depth treatment of environments
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CA Design issues: Context
Determination
• Context determination: acquisition, accuracy particularly of
user context can be complex
• Active versus passive context acquisition
• Single shot (static) versus dynamic acquisition
• Heterogeneous context representation (syntax) and
semantics, interoperability
• Context distribution: Local context producer but remote
context consumer
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User Context Determination
4 approaches
• Combine several low-level sensor inputs to better infer user
context,
• Can Query user profile or model: abstraction that
characterises the user, preferences the user expresses,
• Ask users to define their own context.
• Observing user interaction
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Static versus Dynamic CA
• Static environment context
• Dynamic environment context:
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Context Adaptation Benefits
• Many useful Applications:
–
• Reduces information overload on users
• Lessen cognitive load on users
• Filter information to fit a mobile device's limited and
physically moving display,
–
• Disabled people
–
• Improve Regulation & Control
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Context-awareness: Challenges
• 1. User Contexts may be incorrectly, incompletely, imprecisely
determined or predicted, ambiguous
• 2. Environment Contexts may be incorrectly, incompletely, imprecisely
defined, determined or predicted.
• 3. Contexts may exhibits a range of spatial-temporal characteristics
• 4. Contexts may have alternative representations
• 5.Contexts may be distributed and partitioned, composed of multiple
parts that are highly interrelated
• 6. Contexts may generate data huge volumes
• 7. Context sources and local processes often need to embedded in a
low resource infrastructure
• 8. Context use can reduce the privacy of humans
• 9. Awareness of context shifts can distract users
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Lecture Outline
•
•
•
•
•
•
•
•
•
Types of Context and Context Properties
Context Aware Life Cycle
Context Adaptation
Spatial-Awareness 
Mobile User Context Awareness: Call Routing
Content Adaptation for Mobile Terminals
Temporal awareness 
Composite Context Awareness
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Spatial-Awareness Overview
1.
2.
3.
4.
Trigger spatial-aware services
Sense / determine current Location
Determine the spatial context
Service adaptation: adapt spatial information
view w.r.t. to location
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Spatial-Aware Applications
Applications which trigger use of spatial aware
• Navigation, e.g., I'm lost, where is nearest Metro station?
• Notification of context change: e.g. traffic queue ahead,
change route..
• Querying location context, e.g. What speed limit on this road?
• Personal Emergency: e.g. medical and Roadside
• Emergency Service Operations: e.g., Are flammables
nearby?
• Enterprise Asset Tracking: e.g. “Where is water supply?
• Public Asset Tracking e.g. where is the train now?
• Personal Asset Tracking e.g. I lost my PDA, where is it now?
• Location / time based offers, e.g. Free mobile phone calls
while you are in location X
• Location & time synchronisation: e.g., ImaHima users
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Location-Aware vs Spatial Aware vs
Composite Spatial Aware
Triggering
• Awareness of a location – a point in 3D space
• Awareness of a location in relation to another location
• Awareness of a location in relating to its surrounding 2D
space
• Composite spatial awareness
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Location Determination Methods
Several common Methods
• Proximity Analysis
• Triangulation
• Time Difference of Arrival (TDOA), Multi-lateration
• Trilateration
• Received Signal Strength (RSS)
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Location Determination :
Triangulation
If distance AB, angles at A and B are known
then X and Y can be determined using basic
trigonometry
O
Sin A = Y / a
a
Sin B = Y / b
Y
b
Y = a * Sin A = b * Sin B
Cos A = X / a
X = a * Cos A = AB – b * Cos B
A
X
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Location determination: TDOA
• Time Difference of Arrival (TDOA), Multilateration
• TOA measurement of time signal sent vs. time received:
distance d = time t * signal propagation speed s.
– N.B. Assumes accurate clock synchronisation, sender knows time
of transmission
• TDOA or measurement at 2 or more receivers (or sent from
2 or more senders)
– use to estimate the difference in distances between the 2.
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Location Determination: Trilateration
•
•
Trilateration: uses absolute measurements of time-ofarrival from three or more sites
Trilateration is a method of determining the relative
positions of objects using the geometry of triangles in a
similar fashion as triangulation.
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Location determination: Trilateration
X
Y RA
A O
RB
B
C
RC
3 Equations to determine location of point O
w.r.t. known locations A,B, and C on a 2D plane
RA2 = X2 +Y2
RB2 = (X-(AO+OB))2 +Y2
RC2 = (X-AO)2 +(Y-OC)2
Use substitution to get X and Y
X = (RA2 - RB2 + (AO+OB)2 ) / 2 (AO+OB)
Y = (RA2 - RC2 + AO2+OC2 ) / 2OC) – AOX / OC
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Location Determination: RSS
• Received Signal Strength (RSS)
Estimate the RF signal strength at a receiver
• Knowing the transmission signal strength
• Knowing the attenuation of the signal as a function of
distance and signal transmission strength,
– e.g., 1/r2
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Location Determination: Range
• IR / BlueTooth: ?
• RFID systems: ?
• WLAN: ?
• GPS: ?
• GSM: ?
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Location Determination: Uncertainty
•
Distance & timing measurements has some uncertainty in
practice:
–
–
–
–
–
–
•
variable attenuation (due to moisture in air etc),
multi-path effects,
reflections,
spot interference,
knowing the time of transmission accurately etc
(see also Chapter 11)
How can we correct for this uncertainty?
–
We can measure signal w.r.t to multiple transmitters to correct for
this variability
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Location Determination: Handling
Inaccuracy & Uncertainty
• Handling the lack of accuracy, uncertainty in the location
• Accuracy requirements for some applications can be
relaxed
• Could use orientation or a priori knowledge of geoattributes to help determine the location,
– .
• Can use hybrid systems or assisted systems that combine
strengths and minimise weaknesses of several systems.
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Location & Other Spatial Abstractions
• Location coordinate in itself is often not so useful, it is too
low-level
• It is the Spatial context for a location that is useful and
gives it the location meaning.
– E.g.,
• Forward-tracking: relation of the current coordination to an
end coordination / future goal
– e.g.,
• Backward tracking: relation of current location coordination
to start coordination, to past routes, to past goals
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Location Awareness: Geographical
Information System (GIS)
• Need spatial services to determine the spatial context
–
• This is a GIS service
• A GIS service needs to do more answer spatial queries, it
also needs to be:
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Location Awareness: Geographical
Information System (GIS)
A GIS system supports services to support:
• Spatial context representations
• Spatial context capture
• Spatial annotation: bind context to geometric object or view
• Coordinate transformation
• Spatial data storage
• Spatial analysis including queries
• Spatial data output & cartography
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Geospatial Information System (GIS)
• A service, such as a Geospatial Information System (GIS)
service, is needed to answer spatial queries
– E.g., “Is there a type of service X within 1 km of here?”.
• GIS services represent real world objects
– such as roads, land use, elevation with digitised spatial data.
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GIS: What the Data Represents
Geospatial data consists of multiple parts:
• Geometrical object
– e.g., point, line, polygon etc
• Geo-attributes that form the spatial context
– e.g.,
– types of feature, and associated attributes, e.g
– Annotations of geometrical object
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GIS: Data Representation
• GIS represents real world objects (roads, land use,
elevation) with digitised spatial data
• Real world spatial objects can be
– discrete objects (house)
– continuous fields (rain fall, elevation)
• Digitised GIS data consists of two parts
– Geometrical objects
– Spatial context / Geo-attributes
GIS: Geometric Data Capture
There are a variety of methods used to capture Geo-context
• Digitizer
– e.g.,
• Scanner
– e.g.,.
• Direct entry of surveyed or sensed data
– E.g.,,
• Photo interpretation of aerial photographs.
– E.g.,
Can configure relative location accuracy vs. absolute
accuracy & level of accuracy.
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GIS: Spatial Context Capture
• Geocoding: derive location from spatial context
–
• Reverse geocoding : derive spatial context from location
–
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GIS Data Capture: Processing
Geo Data after capture usually requires editing
• Vector data must be made "topologically correct" before it
can be used for some advanced analysis.
– Projections
– Adjacency
• To remove errors
– E.g.,
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GIS data coordinate Transformation
•
100+ different coordinate systems exist for positions
•
Likely that measured location co-ordinates & geospatial
object coordinates in GIS will be different
-> Need transformations
•
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GIS Data Storage & Retrieval
•
';
• Many DBs with spatial extensions use GIS data structures
that are based on the Open GIS Consortium (OGC)
Geographical Markup Language (GML) standards
• Spatial databases are optimised?
–
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GIS: Spatial Queries
• Example query, How far, as the crow flies, from Queen
Mary to Mile End Tube?
SELECT (orig.buildingloc<->dest. buildinglloc)*37.5 AS "Distance (kms)"
FROM buildingl orig, buildingl dest
WHERE orig. buildinglname = ‘Queens Building'
AND dest.buildingname = ‘MileEnd Tube Station
• A spatial query involves determining
– which indexed region a spatial object of interest is in where a region
bounds a set of spatial objects
– then locating a specific object within that selected region,
– e.g., determining the distance from Queen Mary (Object D) to MileEnd Tube station (Object A)
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GIS: Spatial Queries
A
D
B
C
X
Y
E
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Spatial Adaptation: GIS Data output
& Cartography
• Some main uses of spatial-adaptation:
– ????
• Cartography is the design and production of maps, or
visual representations of spatial data.
• The vast majority of modern cartography is done with the
help of computers, usually using a GIS. Most GIS software
gives the user substantial control over the appearance of
the data
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GIS Data Output & Cartography
Cartographic work serves two major functions:
• It produces maps and other graphics,
–
• To allow the map to be annotated with symbols and text for
the information of interest,
• Web Map Servers facilitate the exchange of generated
maps information via Web Services,
– e.g., ???
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Lecture Outline
•
•
•
•
•
•
•
•
Types of Context and Context Properties
Context Aware Life Cycle
Context Adaptation
Spatial-Awareness
Mobile User Context Awareness: Call Routing 
Content Adaptation for Mobile Terminals
Temporal awareness
Composite Context Awareness
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Context awareness: Indoor Call
Routing For Mobile Users
• Active Badge Location System of Want et al. begun in 1989
• Location awareness users to route calls through to their
nearest fixed line phone indoors
• Readers detect signals from wearable active badges
–
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Mobile User (ICT) Context awareness:
WAN Call Routing For Mobile Users
• Basic mobile phone location determination ….
• Determine which mobile phone transmitter, its area of
operation (its cell), phone is nearest to.
• Phone users registered in HLR
• When users pass between areas, a cell notifies its VLR
• When a call is made by user B to user A, the call first
queries the VLR
• If A not there, call is made to A’s HLR
•
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Location Determination in A Mobile
Phone Network
Base station / Cell
User B
User A
has moved
Visitor
Location
Register
MSC
Group of Cells
Mobile
Switching
Center
VLR
User B
calls User
A
Home
Location
Register
HLR
Core Packet
Switched
User A
User C
MSC
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Network
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Context awareness: Call Routing For
Mobile Users
• System is aware of users’ location
• Location awareness is a means not the end goal
• Interoperability between mobile terminals / handsets and
network?
• Multimedia content adaption: content to fit resources of
limited resource terminal and terminal access network
– See later, also Chapter 11,
• How to prevent huge choice and volumes overloading
mobile user with limited attention capability?
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Lecture Outline
•
•
•
•
•
•
•
•
Types of Context and Context Properties
Context Aware Life Cycle
Context Adaptation
Spatial-Awareness
Mobile User Context Awareness: Call Routing
Content Adaptation for Mobile Terminals 
Temporal awareness
Composite Context Awareness
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Content Adaptation for Mobile
Terminals
Content adaptation to two main types of ICT are considered
here:
• Adaption to the terminal
• Adaption to the network connecting the terminal
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Content Adaptation for Mobile
Terminals
• UI facilitates presenting and entering information for human
use
• Universal content access entails content access via a
proliferation of interactive devices with diverse capabilities.
–
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UI Context Representation
• The UI context can be defined in a UI device profile.
• There are several different specifications for representing
the UI profile.
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Content Adaptation
• Needed to adapt content for display
• Much content designed for decimetre sized screens:
– But what if displayed on small displays? e..g, mobile phone
– But what if displayed on large screens? e.g., projectors,
• Need Content adaptation this involves:
– Transformation of the created content representation to a different
one used in the access device,
– Adaptation of the (multimodal) interaction
– Adaptation to use a particular device display convention
– Adaptation of the content itself.
• See also the range of UI techniques adapted for use in
small and large displays (Chapter 5)
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Content Adaptation: Network-Aware
• A service that is aware of the characteristics of the physical
network is called underlay-network aware (Chapter 11)
–
• Enhancements are needed to TCP/IP network design to
support more flexible context-aware QoS delivery.
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Lecture Outline
•
•
•
•
•
•
•
•
Types of Context and Context Properties
Context Aware Life Cycle
Context Adaptation
Spatial-Awareness
Mobile User Context Awareness: Call Routing
Content Adaptation for Mobile Terminals
Temporal awareness 
Composite Context Awareness
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Temporal Awareness: Time
• Time may be modelled as a period
–
• Time may be modelled as an instant,
–
• Time can be modelled as a linear sequence
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Time Awareness: Scheduling
Given:
• a set of tasks to perform (the user context),
• a set of resources to use and
• a set of time constraints (the temporal context),
The objective of task scheduling is to allocate times and
resources to user tasks.
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Time Awareness: Scheduling
• Task scheduling is simplest when …
–
• Simple scheduling can involve deriving a personalised
schedule that it a subset of another schedule known a
priori,
– e.g., .
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Time Awareness: Scheduling
Simple job scheduling algorithm is to partial order n tasks in a graph and to search it to
find a path
1T1
2T1
1T2
1T3
Known
execution
Known
time
deadline
Known periods but
flexible execution &
deadline
Task 1
Working
Task 2: Break
to eat & drink
Task 3
Traveling
Task 4
Leisure
2T2
0 1T 1T1
1T2
2T 1T2
2T2
1T3
T1
T1
3T 1T3
3T2
2T1
2T1
4T
4T2
3T1
3T1
1T4 5T
7T
6T
5T2
2T3
1T4
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Lecture Outline
•
•
•
•
•
•
•
•
Types of Context and Context Properties
Context Aware Life Cycle
Context Adaptation
Spatial-Awareness
Mobile User Context Awareness: Call Routing
Content Adaptation for Mobile Terminals
Temporal awareness
Composite Context Awareness 
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Composite Context Awareness for
Mobile Users
Mobility context awareness is a good example of composite
context adaptation.
• Spatial awareness is used to adapt activities with respect to
their locality.
• Information retrieval from remote sources can be
personalised to users’ preferences.
• ICT context-awareness is useful for mobile users so that it
adapts remotely accessed content so that it fits better the
characteristics of mobile access devices and better fits the
bandwidth available in the local wireless access loop.
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Composite Context Awareness for
Mobile Users: Applications
• Navigation
• Automatic annotation of local recordings in the field
•
Filtered content for mobile users w.r.t.
• But what order to do the individual context adaptation in?
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Context Composition Example: CRUMPET
Project System
GPS
Users
User
preferences
User
position
Terminals
Terminal
profile
l
Persona interests
Mediator
Service
capabilities
Link description
Network
Interaction
& Service
Facilitation
Service Providers
e.g., maps, routes, sight and
restaurant recommendations
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CRUMPET Project System
• CRUMPET, Creation of User-friendly Mobile
services PErsonalised for Tourism, EU FP5 Project
system is an example of a composite context
adaptation application.
• In this system, tourism information services such
as maps, routes and sight recommendations can
be adapted to a spatial context that pertains to the
current location, the personal context of a service
uses, the network context and the terminal context,
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The CRUMPE T System
Map components:
• Map of the
nearby “world”
• Start/Edit tour
• Status bar with
proactive “bulb”
My IP address
and port are...
Ok, here are your nearby
points of interests.
Here is my
new location.
Components:
• Map of the “world”
• Diagnostics information
• Client status (Agent and network status)
• Points of interests
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CRUMPET Multi-Agent System Architecture
GPS
Web Browser
Fixed Network Services
User
agent
Client /
Terminal
Agent
Mobile
Device
Contet Adaptation
Service Agent
wireless
Location agent
User modeling agent
Mediator
Agents
Network
agents
Service
agents
Access
Node
Network
agents
Ubiquitous computing: smart devices,
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End user
Services
Context-aware
Middleware
Network
85
Composite Context Awareness:
CRUMPET System
• Particular ordering of context-aware adaptation follows.
• Users’ access terminal profile of memory & display
capabilities is exchanged with system during session start
Localisation is for example used twice
• Current position of a user can be used to constrain a user's
request and to further filter the relevant information.
• Unless the relevant location is specified explicitly, user gets
information relevant for his or her current spatial context.
• user’s movements within region can indicate their interests.
– E.g., a user visits a number of old churches, then he or she is
probably interested in churches and perhaps also other historic
buildings in this town, like an old city hall.
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Composite Context Awareness:
CRUMPET System
• Users generate a lot of potential events of interest as they move.
• These can be exploited for user modelling & to detect & anticipate
relevant user interests.
• Hence, the combined location and personal model context can be
used to such as get me a map of things of interest at a location.
• This is an example of environment context composition in which one
type of context (location) may be used to determine another type of
context (personal preferences) based upon a user context policy.
• Finally, the network profile based upon monitoring the performance
of the local mobile terminal to access node, the content, e.g., a
personalised, location-aware map is adapted to the terminal and
network profile respectively.
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Composite Context Awareness:
• Note the context composition challenges (Revision from
Chapter 5 slide set a )
• Handling heterogeneity of representation
• Handling heterogeneity of meaning
• Mediating and coordinating context aggregation
• Ordering the adaptation to individual contexts
• Different weightings for combining contexts
• Handling uncertainty in combining contexts
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CRUMPET System Screenshots
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CRUMPET System Screenshots
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CRUMPET System: Fat-client
Architecture
TA
Satellite
Wireless Station
Service Provider
GSA
WMTP - full control over wireless link
Fixed Network
SCA
Wireless Station
Service Provider
MAPA
CA
MA
MA
DCA
CASA
SA
Service Provider
CCA
CA
UMA
Agent processing complete control over GSM
triangulation, GPS and browser
Dillo
CRUMPET Services
This deployment architecture has a larger client-side
Footprint and is suitable for deploying in
high end PDAs and PCs
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CRUMPET System: Thin-Client
Architecture
TA
Satellite
Wireless Station
Service Provider
GSA
HTTP
HTTP - no control over link
Fixed Network
SCA
JAVA process very little control
over GPS and browser
Wireless Station
Service Provider
MAPA
ExplorerCE
MA
DCA
CASA
Service Provider
CRUMPET Services
CCA
CA
SA
UMA
This deployment architecture has a very small client-side footprint and is
suitable for deploying in low end PDAs and suitably equipped mobile 'phones
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Lecture Outline
•
•
•
•
•
•
•
•
Types of Context and Context Properties 
Context Aware Life Cycle 
Context Adaptation 
Spatial-Awareness 
Mobile User Context Awareness: Call Routing 
Content Adaptation for Mobile Terminals 
Temporal awareness 
Composite Context Awareness 
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Revision
For each chapter
• See book web-site for chapter summaries, references,
resources etc.
• Identify new terms & concepts
• Apply new terms and concepts: define, use in old and
new situations & problems
• Debate problems, challenges and solutions
• See Chapter exercises on web-site
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Exercises: Define New Concepts
• Context-awareness
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Exercise: Applying New Concepts
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