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Sources of Contextual Information A user’s context information is distributed across a A user’s context information is distributed across a
number of disparate resourcesnumber of disparate resources CalendarCalendar Location trackingLocation tracking Address bookAddress book Buddy listsBuddy lists WeatherWeather
Available resources vary from one user to anotherAvailable resources vary from one user to another ……and over timeand over time
e.g. roaming across different networkse.g. roaming across different networks
MotivationMotivation:: Campus as “everyday life microcosm”Campus as “everyday life microcosm”
ObjectiveObjective:: Enhance campus life through context-aware services Enhance campus life through context-aware services
accessible over the WLANaccessible over the WLAN Methodology:Methodology:
Involve stakeholders in the designInvolve stakeholders in the designStudents and other members of the communityStudents and other members of the community
Evaluate and extrapolate to other environmentsEvaluate and extrapolate to other environmentsMobile Commerce, Mobile Enterprise, etc.Mobile Commerce, Mobile Enterprise, etc.
““When driving, I don’t want to receive instant messages”When driving, I don’t want to receive instant messages” Service invocation rulesService invocation rules
Automated service identification and accessAutomated service identification and access Map contextual attributes onto different resources Map contextual attributes onto different resources
(personal and public)(personal and public) Privacy rulesPrivacy rules
Access control rulesAccess control rules ““Only my classmates can see my location”Only my classmates can see my location”
Obfuscation rulesObfuscation rules ““My classmates can only see the building I am in but My classmates can only see the building I am in but
Asserting elementary needs for authorized information
Pre-check access rights
Post-checkaccess rights
Fetch usefulstatic knowledge
Application ofobfuscation rules
Query contextassertionQuery
Assertion ofauthorized knowledge
Result
Call relevant external services
Example : Example : Query from John inquiring about Mary’s locationQuery from John inquiring about Mary’s location the sender of the query is Johnthe sender of the query is John John’s query requires accessing Mary’s locationJohn’s query requires accessing Mary’s location
1.1.Is John allowed to see Mary’s location given what we know Is John allowed to see Mary’s location given what we know about the context of the query?about the context of the query?
2.2.Mary said she only allows colleagues to see her location when Mary said she only allows colleagues to see her location when she is on campusshe is on campus
3.3.John is a colleague of MaryJohn is a colleague of Mary Access location tracking functionality or Mary’s calendarAccess location tracking functionality or Mary’s calendar Is Mary on campus?Is Mary on campus? Mary is willing to disclose the building but not the room she is Mary is willing to disclose the building but not the room she is
and invocation of external sourcesand invocation of external sourcesof knowledge (e.g. public web services of knowledge (e.g. public web services and and personal resources)and and personal resources)
Privacy layerPrivacy layer: Enforces privacy rules: Enforces privacy rulesaccess control & obfuscation access control & obfuscation
All facts represented in OWLAll facts represented in OWL Backward chaining Backward chaining migration rulesmigration rules: privacy : privacy
rules, service rules, static migration rulesrules, service rules, static migration rules
Integration with calendar, location tracking, user Integration with calendar, location tracking, user profile, etc.profile, etc.
EvaluationEvaluation Context awareness adds valueContext awareness adds value Requires access to a broad range of resources/attributesRequires access to a broad range of resources/attributes Privacy concerns have to be addressedPrivacy concerns have to be addressed
Additional validation on context-aware enterprise and Additional validation on context-aware enterprise and DoD applicationsDoD applications
Concluding Remarks Context awareness helps overcome the limitations of mobile Context awareness helps overcome the limitations of mobile
devices and the time criticality of mobile scenariosdevices and the time criticality of mobile scenarios Context awareness makes privacy even more criticalContext awareness makes privacy even more critical Our experiments indicate that user preferences are often complexOur experiments indicate that user preferences are often complex
Incl. context-sensitive preferencesIncl. context-sensitive preferences Capturing these preferences is far from trivialCapturing these preferences is far from trivial
Default profiles, learning, dialogs, Default profiles, learning, dialogs, How far can we go?How far can we go?
Semantic Web approachSemantic Web approach Allows for policies that refer to concepts introduced in any Allows for policies that refer to concepts introduced in any
number of domain-specific ontologiesnumber of domain-specific ontologies Opportunities for reconciliation with P3P/APPELOpportunities for reconciliation with P3P/APPEL