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CAPIM: A Context-Aware PlatformCAPIM: A Context Aware Platform using Integrated Mobile Services
Ciprian Dobre, Flavius Manea, Valentin Cristea
U i it POLITEHNICA f B h t R iUniversity POLITEHNICA of Bucharest, RomaniaEmails: [email protected], {ciprian.dobre, valentin.cristea}@cs.pub.ro
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OUTLINE
• Scope and motivation
o Context – awareness
• CAPIM platform
o Architecture
o Pilot implementation
• Conclusions and future work
Context - awareness
• Context : Information that can be used to characterize the situation of an entity
C t t A t f t th t• Context – awareness: A property of a system that uses context to provide relevant information and/or service to the user
Physical world
Logical worldInformation
ContextC t tPhysical world
Computer‐aware information
Context
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CAPIM: Context-Aware Platform using Integrated Mobile services
• Platform to support construction of context-aware applications
S i f ll ti t i ti f t t• Services for collecting, storing, aggregation of context
• Context-enabled rule execution engine
• Visualization platform
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ArchitectureUtilities
LocalizationLocalizationInformationInformation RecommendationRecommendation
Actions
Activities
Context Data
RuleWarehouse
Data
ExternalServices CAPIMCAPIMCAPIMCAPIM
Context Manager
Services
AggregationService
StoringServiceKnowledge
Management Social and profileManagement
Security
Location User
MonitoringRepository
CommunicationService
g
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CAPIMCAPIM CAPIM
UserProfileHardware
Context framework
Module 1Utilities Applications
Module 2
Utilities Applications
. .
Context Manager
Actions
Module n
.
Rule EngineRules
Data acquisition Context-Aware Framework
Applications
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Context Monitoring
Aggregation and Storage Service
Core
Execution PlatformContext Manager
Push PullModules
Web Service
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PushModule
PullModuleRepository
Context acquisition modules
• Pusho The Context Manager is notified by the module when the context
changes and the corresponding values are updated• Pull
o Information from a pull module has a limited life span. When this time period is exceeded the Context Manager will try to updatetime period is exceeded the Context Manager will try to update the context data.
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The levels of abstraction
Exploitation
Situation and context identificationContext-as-a-process:user is movingusers located near
Perception: symbolic observables
Raw data is collected:
Data is abstracted: location is EG303
Sensing: numeric observations Raw data is collected: WiFi signals, GSM cells, etc.
Taking the output “the user is running” and “the user has a high pulse” for example, determine a context such as “the user is jogging”.
Considering output “user under the car”, determine if the user was hit by the car or
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just inspecting its engine.
Data model…
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"xmlns:foaf="http://xmlns.com/foaf/0.1/"xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:org="http://www.w3.org/ns/org#"><foaf:Person rdf:about="andreea.starparu">
<org:memberOf rdf:resource="Gr341C3"/><foaf:name>Andreea Starparu</foaf:name><foaf:nick>andreea.starparu</foaf:nick><foaf:interest>Semantic_Web</foaf:interest><foaf:interest>Distributed Systems</foaf:interest><foaf:interest>Distributed Systems</foaf:interest><rdfs:subClassOf rdf:resource="prezentare_licenta"/><wail:location>
<geo:Point><geo:lat>47.235</geo:lat><geo:long>25.581</geo:long>geo:long 25.581 /geo:long
</geo:Point></wail:location>
</foaf:Person><ical:vevent rdf:about="prezentare_licenta"/>
<ical:summary>thesis presentation</ical:summary><ical:dtstart rdf:datatype="xsd:data">2011-07-11</ical:dtstart><ical:dtend rdf:datatype="xsd:data">2011-07-15</ical:dtend><ical:location>
<geo:Point><geo:lat>47.235</geo:lat><geo:long>25 581</geo:long>
Logical world
Ph i l ld
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<geo:long>25.581</geo:long></geo:Point>
</ical:location></ical:vevent>
</rdf:RDF>
Semantic world Physical world
The rule engine
C t t S i R tiContext updates are
i d b ifi i
Evaluate rules
Context Service Routine triggered by notifications or validity expirations
O l th l hi hEvaluate rules Only the rules which are affected by context changes are evaluated
ActionsAn action is executed when a rule passes the
l tievaluation
Rules
Context Conditions
Action
Conditions are defined using context parameters (an enumeration of keys
Each action is defined as a autonomous applicationparameters (an enumeration of keys
available as environment variables) and some predefined operators which will help us to build expressions
autonomous application
p p
Rule = Rule OR Rule | Rule AND Rule | RuleImplementation
Context Parameter OperatorValues True
False
A rule example
<rules-config><rule-definitions>
<rule-def name="DistributedSystemEventNotification" action="category.EVENT_NOTIFICATION">
<rule name="userIsFree" /><operator name="AND" /><rule name="userHasInterest" />
</rule-def></rule-definitions><rule-implementations>
<rule-impl name="userIsFree" class="rules.StringFieldEquals"><property name="argField" value="CURRENT_ACTIVITY"/>
<property name="target" value="free"/></rule-impl>
</rule-implementations><rule-implementations>
<rule-impl name="userHasInterest" class="rules.StringFieldContainedInList">
<property name="argField" value="INTERESTS"/><property name="target" value="Distributed Systems"/>
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</rule-impl></rule-implementations>
</rules-config>
An experimental application – SmartSuggests
Do you happen to
know aknow a restaurant nearby?
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An experimental application – SmartSuggests
Context‐Aware Middleware Rule Engine
Set of RulesSuggestiongg
The rule
<?xml version="1.0" encoding="UTF-8"?> <rules-config>
l d fi iti<rule-definitions> <rule-def name="showRestaurantSuggestion" action="category.PLACE_SUGGESTION" parameter="restaurants"> pa a e e es au a s<rule name="isLunchTime" />
</rule-def> </rule-definitions> <rule implementations><rule-implementations>
<rule-impl name="isLunchTime" class="rules.IntFieldBetween"> <property name="argField" value="TIME"/> <property name="targetStart" value="13"/> p p y g<property name="targetEnd" value="14"/>
</rule-impl> </rule-implementations> </rules config></rules-config>
Conclusions and future work
• CAPIM – context-aware platform for context-aware applications
d t t t t ditio adapt to context conditions,
o understand more easily the user needs,
• A pilot implementation of the contextualization platform has proven the great advantages it provides in terms of simplicity and flexibility.simplicity and flexibility.
• Future improvements of CAPIM involve the increase of energy efficiency, which is a critical property for software gy y p p yon portable devices.
