DTIC ADA544694: Privacy Preservation in Context-Aware Systems

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TitleofThesis: PrivacyPreservationinContext-AwareSystems
NameofCandidate: PramodJagtap
M.S. in Computer Science,
2011
ThesisandAbstractApproved:
Dr. AnupamJoshi
Professor
DepartmentofComputerScienceand
ElectricalEngineering
DateApproved:
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2011 2. REPORT TYPE 00-00-2011 to 00-00-2011
4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER
Privacy Preservation in Context-Aware Systems
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6. AUTHOR(S) 5d. PROJECT NUMBER
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7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION
University of Maryland,Department of Electrical Engineering,College REPORT NUMBER
Park ,MD,20742
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Approved for public release; distribution unlimited
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14. ABSTRACT
Recent years have seen a confluence of two major trends ? the increase of mobile devices such as smart
phones as the primary access point to networked information and the rise of social media platforms that
connect people. Their convergence supports the emergence of a new class of context-aware geosocial
networking applications. While existing systems focus mostly on location, our work centers on models for
representing and reasoning about a more inclusive and higher-level notion of context, including the user?s
location and surroundings, the presence of other people and devices, feeds from social networking systems
they use, and the inferred activities in which they are engaged. A key element of our work is the use of
collaborative information sharing where devices share and integrate knowledge about their context. This
introduces the need for privacy and security mechanisms. We present a framework to provide users with
appropriate levels of privacy to protect the personal information their mobile devices are collecting
including the inferences that can be drawn from the information. We use Semantic Web technologies to
specify high-level, declarative policies that describe user?s information sharing preferences. We have built
a prototype system that aggregates information from a variety of sensors on the phone, online sources, and
sources internal to the campus intranet, and infers the dynamic user context. We show how our policy
framework can be effectively used to devise better privacy control mechanisms to control information flow
between users in such dynamic mobile systems.
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ABSTRACT
TitleofThesis: PrivacyPreservationinContext-AwareSystems
PramodJagtap,MastersinComputerScience,2011
Thesisdirectedby: Dr. AnupamJoshi,Professor
DepartmentofComputerScienceand
ElectricalEngineering
Recent years have seen a confluence of two major trends – the increase of mobile de-
vices such as smart phones as the primary access point to networked information and the
rise of social media platforms that connect people. Their convergence supports the emer-
gence of a new class of context-aware geosocial networking applications. While existing
systemsfocusmostlyonlocation,ourworkcentersonmodelsforrepresentingandreason-
ingaboutamoreinclusiveandhigher-levelnotionofcontext,includingtheuser’slocation
and surroundings, the presence of other people and devices, feeds from social networking
systems they use, and the inferred activities in which they are engaged. A key element of
our work is the use of collaborative information sharing where devices share and integrate
knowledge about their context. This introduces the need for privacy and security mecha-
nisms. We present a framework to provide users with appropriate levels of privacy to pro-
tect the personal information their mobile devices are collecting including the inferences
that can be drawn from the information. We use Semantic Web technologies to specify
high-level, declarative policies that describe user’s information sharing preferences. We
have built a prototype system that aggregates information from a variety of sensors on the
phone, online sources, and sources internal to the campus intranet, and infers the dynamic
user context. We show how our policy framework can be effectively used to devise better
privacy control mechanisms to control information flow between users in such dynamic
mobilesystems.
Privacy Preservation in Context-Aware Systems
by
Pramod Jagtap
ThesissubmittedtotheFacultyoftheGraduateSchool
oftheUniversityofMarylandinpartialfulfillment
oftherequirementsforthedegreeof
MS
2011
(cid:13)c CopyrightPramodJagtap2011

DedicatedtoEbiquityLab
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ACKNOWLEDGMENTS
IwouldliketoexpressmysinceregratitudetomyadvisorDr. AnupamJoshi. Ithank
him for the constant support and guidance, and for his continued belief in me throughout
thisthesiswork. Hehasalwaysgivenmefullsupportandallowedmetoexplorenewtopics
and research problems that drove my interests. I am thankful for his words of advice and
manyskillsIhavegainedbyworkingwithhim.
Thanks to Dr. Tim Finin and Dr. Laura Zavala for all the valuable suggestions
throughout my work at Ebiquity lab. I would like to thank all Dr. Tim Finin, Dr. Ye-
lena Yesha and Dr. Laura Zavala for graciously agreeing to be on my thesis committee.
They have always made themselves available and accessible and I thank them for their
time,suggestionsandimportantadvice.
AlltheEbiquitygroupmembershavebeenextremelysupportiveinbuildinganatmo-
sphere conducive to research. It has been a great joy working with them throughout the
year.
I extend my sincere thanks to National Science Foundation (award 0910838) and the
AirForceOfficeofScientificResearch(MURIGrantFA9550-08-0265).
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TABLE OF CONTENTS
DEDICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
LISTOFFIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
LISTOFTABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
Chapter1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter2 BACKGROUNDANDRELATEDWORK . . . . . . . . . . . 5
2.1 PoliciesandtheSemanticWeb . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Geo-socialnetworkingsystems . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter3 SYSTEMARCHITECTURE . . . . . . . . . . . . . . . . . . 10
3.1 PrivacyRelatedComponents . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.1 Contextontology . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.1.2 Knowledgeabouttheuser . . . . . . . . . . . . . . . . . . . . . . 17
3.1.3 Privacypreferences . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.1.4 ReasoningArchitecture . . . . . . . . . . . . . . . . . . . . . . . . 20
3.2 PrivacyPreservation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
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