Post on 22-Jan-2018
SOCIALMEDIA&POLICING:ComputationalApproachesto
EnhancingCollaborativeActionbetweenResidentsandLawEnforcement
Niharika SachdevaPhDThesisDefenseTCSResearchScholarniharikas@iiitd.ac.in
WhoamI?� Ph.D.student� SeniorResearchScientist@PhilipsResearch,India� TCSResearchScholar� Doneworkincomputermediatedcommunicationandusablesecurity(HCI)
� Researchinterests� Collaborationandcommunication� MachineLearning� Humancomputerinteraction� Usablesecurityandprivacy
2
IndiaisBiggestPoliceDepartment
3
238PoliceOfficersper100,000
129PoliceOfficersper100,000
327PoliceOfficersper100,000
WhichisIndia?SouthAfrica?USA?
4
MostOverworked– NeedHelp!
CollaboratingwithResidents
One– waycommunication
5
Two– waycommunication
Asynchronous,RemoteandPublicplatformforInteraction
NeedforImprovedCollectiveActionandAccountability
HowaboutInteractingwithPoliceonOSM?
6
� HowmanyofyouareonFacebook/Twitter?� Howmanyofyouknowaboutsocialmediapolicepages/accountsorusethemtointeractwithpolice?
NewMediatoStayConnected
7
ThreeDimensionsforSuccessfulCollaboration
High
Moreaccurateanalytical andmodelingtools
Low
High
High
Morepeople involved
Moredata available
PoliceResident
Charalabidis, Yannis, and Sotirios Koussouris, eds. Empowering open and collaborative governance: Technologies and methods for online citizen engagement in public policy making. Springer Science & Business Media, 2012.
8
Challenges:SuccessfulCollaboration� Identifyinghowsocialmediacansupportday-to-dayinteractionbetweenpoliceandresidents
� AnalyzingandExtractingmeaningfulandactionableinformationfromenormousdata� Unstructuredandunconstrained� Inferringactionableinformation� Quantifyingbehavior(emotionsandlinguisticattributes)
� Maintaining responsiveness toresidents� Promptnessandtimelyactionbypoliceonsocialmedia� Engagingwithpeople
9
High
Moreaccurateanalyticalandmodelingmethods
Low
High
High
Morepeople involved
Moredataavailable
Challenges:SuccessfulCollaboration� Identifyinghowsocialmediacansupportday-to-dayinteractionbetweenpoliceandresidents
� AnalyzingandExtractingmeaningfulandactionableinformationfromenormousdata� Unstructuredandunconstrained� Inferringactionableinformation� Quantifyingbehavior(emotionsandlinguisticattributes)
� Maintaining responsiveness toresidents� Promptnessandtimelyactionbypoliceonsocialmedia� Engagingwithpeople
10
High
Low High
Morepeople involved
Moredataavailable Moreaccurateanalytical
andmodelingmethods
High
Challenges:SuccessfulCollaboration� Identifyinghowsocialmediacansupportday-to-dayinteractionbetweenpoliceandresidents
� AnalyzingandExtractingmeaningfulandactionableinformationfromenormousdata� Unstructuredandunconstrained� Inferringactionableinformation� Quantifyingbehavior(emotionsandlinguisticattributes)
� Maintaining responsiveness toresidents� Promptnessandtimelyactionbypoliceonsocialmedia� Keepengagingwithpeople
11
High
Low High
Morepeople involved
Moredataavailable Moreaccurateanalytical
andmodelingmethods
High
Challenges:SuccessfulCollaboration� Identifyinghowsocialmediacansupportday-to-dayinteractionbetweenpoliceandresidents
� AnalyzingandExtractingmeaningfulandactionableinformationfromenormousdata� Unstructuredandunconstrained� Inferringactionableinformation� Quantifyingbehavior(emotionsandlinguisticattributes)
� Maintaining responsiveness toresidents� Promptnessandtimelyactionbypoliceonsocialmedia� Engagingwithpeople
12
High
Moreaccurateanalyticalandmodelingmethods
Low
High
High
Morepeople involved
Moredataavailable
CoreThesisQuestion
Howcansocialmediaplatformsbeutilizedtosupport,analyze,
andenhanceday-to-daycollaborativeinteractionbetween
policeandresidentsusingcomputationalmethods?
13
Contributions� Identifyneedforsocialmediasupport incollaborativepolicing
� Quantifyandmineunstructureddatatoanalyze communicationattributesand
actionableinformation
� Proposeamethodtoenhance collaboration
� Policeresponsivenessusingrequest–responsedetectionframeworkandpolice
responsequantificationtoresidents
� Imagesretrievalarchitectureforimprovedcollectiveactionusingusergenerated
content
14
Contributions� Identifyneedforsocialmediasupport incollaborativepolicing
� Quantifyandmineunstructureddatatoanalyze communicationattributesand
actionableinformation
� Proposeamethodtoenhance
� Policeresponsivenessusingrequest–responsedetectionframeworkandpolice
responsequantificationtoresidents
� Imagesretrievalarchitectureforimprovedcollectiveactionusingusergenerated
content
15
ResearchProblem
InitialCoding
AdvancedMemo
TheoreticalSamplingnewdata
Integratingfordimensions
NeedforSupport:RequirementElicitation� Whatopportunities socialmediaoffersforsupportingcollaboration?
� Whatchallenges policeandresidentscanfacewhileadoptingsocialmediaforcollaboration?
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• 17Interviews• 200Surveys
• 20Interviews• 402Surveys
Multi-stakeholder& MixedMethod
LimitedGroundedTheoryApproach
Why Which ForWhom Challenges
17
EDUCATEDYOUNGANYONE
NeedforSupport:RequirementElicitation
PoliceOfficers ResidentCommunities
CollaborativePlatform
CollaborativeEcosystemandActors
InteractionLayer
MeaningfulInformation
Acknowledgement/ResponseSystem
VerificationandCredibilityAssessment
Lessons
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Contributions� Identifyneedforsocialmediasupport incollaborative
policing
� Quantifyandmineunstructureddatatoanalyze
communicationattributesandactionableinformation
� Proposeamethodtoenhance
� Policeresponsivenessusingrequest–responsedetection
frameworkandpoliceresponsequantificationtoresidents
� Imagesretrievalarchitectureforimprovedcollectiveaction
usingusergeneratedcontent19
High
Low High
Morepeople involved
Moredataavailable Moreaccurateanalytical
andmodelingmethods
High
QuantifyingInteraction� Exploringthefeasibilityofsocialmediainquantifyingattributesof
communication
� Identifyingbehavioralattributeslikeaffectiveexpression,engagementand
socialandcognitiveresponseprocesses
20
ResidenttoResident
ResidenttoPolice
PolicetoResident
PolicetoPolice
MixedMethodApproach:DataCollection
21
85PublicandofficialPoliceDepartment
Averageage3years(from2010– April2015)
47,474wallpostsand85,408statusupdates
DTw/≥1Comment P&C CTotalDT
85,408
47,474
46,845
24,984
5,519
17,196
41,326
7,788
PP&C
RP&C
PC
CC
QuantitativeData QualitativeAnalysis
MixedMethodApproach:DataCollection
22
85PublicandofficialPoliceDepartment
Averageage3years(from2010–April2015)
47,474wallpostsand85,408statusupdates
DTw/≥1Comment P&C C
TotalDT
85,408
47,474
46,845
24,984
5,519
17,196
41,326
7,788
PP&C
CP&C
PC
CC
QuantitativeData
1600commentson255posts
Posts&Comments
Collectedpublicposts,21July- 21Aug2014
QualitativeAnalysis
QuantifyingInteractionforMeaningfulInformation� ContentClusterIdentification
� Natureofcontentandtopics
� EmotionalExchange Quantification
� Natureofemotionsandaffectiveexpression
� CognitiveandSocialOrientationQuantification� Typeoflinguisticattributesthatcharacterizecognitiveandsocialorientation
� Engagement (Response)Quantification� Quantityandnatureofengagement
23
MixedMethodApproach:Methods
24
Topics
• Unigram (N) GramAnalysis• K-meansClusters withK-means++seeding
Emotional
• Valence• Arousal
Socialandcognitive
• InterpersonalFocus• SocialOrientation• Cognition
Engagement
• No.ofpoliceandresidentwhocommentinDTs• DistinctcitizenswhocommentinDTs• Shannon’sWienerDiversityindex• Averageno.of likesandcomments
LIWCandAnewDictionary
LIWCDictionary
Quantitative Data ThematicInductiveAnalysis
MixedMethodApproach:Methods
25
Topics
• Unigram (N) GramAnalysis• K-meansClusters withK-means++seeding
Emotional
• Valence• Arousal
Socialandcognitive
• InterpersonalFocus• SocialOrientation• Cognition
Engagement
• No.ofpoliceandresidentwhocommentinDTs• DistinctcitizenswhocommentinDTs• Shannon’sWienerDiversityindex• Averageno.of likesandcomments
LIWCandAnewDictionary
LIWCDictionary
QuantitativeData ThematicInductiveAnalysisValidateandCharacterize
Typeofsub-topicsinResidentsPosts
Direct/IndirectConcerns+
Styleofcommunication
TypeofEngagement
26
Unigram Freq. Unigram Freq.
rules 0.015 safety 0.012safety 0.014 following 0.011
violations 0.014 notice 0.010challans 0.011 prosecuted 0.009please 0.011 movement 0.008citizens 0.01 complaint 0.008
Focusonadvisories,thestatusofdifferentcasesbeinginvestigated
(MannWhitneyUtest,p<.05,z=−3.57)
Mostpoststendtorequestpolicetotakeactionontheircomplaints
Unigram Freq. Unigram Freq.
please 0.026 people 0.022take 0.021 please 0.02action 0.019 one 0.019people 0.019 take 0.016one 0.019 action 0.015time 0.017 time 0.015
HigherReferenceto“people”
QuantifyingInteractionforMeaningfulInformation
K-Means++Seeding:ClustersofTopics
� Policeinitiateddiscussionsaremorefocusedthancitizeninitiated.
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Awarenessdrive/safetycampaigns
Prosecuted/actiontakenreports
Advisoriesonsituations
Newspaperarticles
Citizentipsandcomplaints
Neighbourhood problems
Missingpeople
Appreciation
QuantifyingInteractionforMeaningfulInformation
QuantifyingInteraction� TopicIdentification
� Natureofcontentandtopics
� EmotionalExchange Quantification
� Natureofemotionsandaffectiveexpression
� CognitiveandSocialOrientationQuantification� Typeoflinguisticattributesthatcharacterizecognitiveandsocialorientation
� EngagementQuantification� Quantityandnatureofengagement
28
� Negativesentimenthigherinresidentinitiatedthreadsthanpolice
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CP&C CC
Avg Std.dev Avg Std.devNA 0.021 0.03 0.018 0.04Anx 0.001 0.01 0.003 0.02Anger 0.006 0.02 0.005 0.02Arousal 4.4 1.74 3.9 2.16
16.67%higherinCP&C
12.82%higherinCP&C
Higherarousalandnegativeaffecttobemarkersofsensitisationbecauseofcrime!
Cp&c CcAvg Std.dev Avg Std.dev
NA 0.021 0.03 0.018 0.04Anx 0.001 0.01 0.003 0.02Anger 0.006 0.02 0.005 0.02Arousal 4.4 1.74 3.9 2.16
200%higherinCc
(Mann-WhitneyU, p<.01)
(Mann-WhitneyUp<.01)
MeaningfulInformationQuantification:Emotions
� Discussionthreadsinvolvingjustthecitizensarehighlyself-attentionfocused
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Likelycitizensmostlyexpresstheirownconcernsthattheyfacewithothers
CP&C CC
ppron 0.062 0.059 0.045 0.056i 0.008 0.017 0.014 0.033
shehe 0.002 0.01 0.003 0.003they 0.005 0.013 0.008 0.008
75%More
I havelivedintheUKandallthetimeIhaveneverheardanyonehonking.…. ifIseeanyonewhodon'tcomply?
(UTestp<.01,z=−16.02)
MeaningfulInformationQuantification:SocialandCognitiveOrient.
Self-focused
31
MyVehicleKA-02-HW-3183whitecolorHondaDiowasstolenfromKadamba Hotel(NearModiHospital),RajajiNagar onFriday(25th July)eveningbetween6:30-7:45PM.Pleasehelpintracingmyvehicle.
DearBCP,though IstayatJPNagar,butbeingpartofKSFCLayoutRWA(Banaswadi Policestation),IgottoknowthattherearefrequentproblematKSFCLayoutnearBBMPHall...….
Accountability:MeaningfulInformation
32
WordTreevisualizationsofpostsinwhichresidentsquestioned policeusingthewordwhy.
QuantifyingInteraction� TopicIdentification
� Natureofcontentandtopics
� EmotionalExchange Quantification
� Natureofemotionsandaffectiveexpression
� CognitiveandSocialOrientationQuantification� Typeoflinguisticattributesthatcharacterizecognitiveandsocialorientation
� EngagementQuantification� Quantityandnatureofengagement
33
EngagementQuantification� ContentGeneration
34
Police+Citizens 55,028 1,79,176 17,124 12,630
CitizensOnly 54,982 1,79,176 17,081 12,630
Entropy 4.39 4.96 3.23 3.6
Police Resident
26%lower
10.28%lower
Lowerentropy: largenumberofcommentsarepostedbyasmallnumberofcitizensandpolice
Engagement(Response)Type
35
Ignored(#83)
Acknowledged (21.3%)
Reply
FollowUp(10%)
DearX,Wewilltakeallpossiblelegalmeasuresinthisregard.Thankyou.
DearX,Pleaseprovide thepolicestationdetails.Thankyou.
[Receivednoreply]
DearX,Thisposthasbeenforwarded toappropriatePoliceStation….
DearX,Pleaselodgeacomplaintatyournearestpolicestationwiththedetails…..
44.3%
22%172posts
Lessons
36
ResponsivenessAccountability
QuantifyAnd
Extract
NeedforEnhancingPoliceResponsiveness
Contributions� Identifyneedforsocialmediasupport incollaborativepolicing
� Quantifyandmineunstructureddatatoanalyze communicationattributesand
actionableinformation
� Proposeamethodtoenhance
� Policeresponsivenessusingrequest–responsedetectionframeworkandpolice
responsequantificationtoresidents
� Imagesretrievalarchitectureforimprovedcollectiveactionusingusergenerated
content
37
ServiceableRequests
“Amessagethatsolicitsaresponseinaformofanactionorinformation
fromthepolice”
38TucsonPolice.2016.CallsforService.https://www.tucsonaz.gov/police/terms.(May2016).
Low
High
High
High
Morepeopleinvolved
Moredataavailable
Serviceablev/sNon-ServiceablePosts
39
NeedmoreInformation
Forward
GiveSolution
Copsdrivingwrongside[ofroad]nearXXXhotel..whatactionwillbetakenagainstthem
Date:4/11/2015(Wednesday),Time:10:17pm,Number:[withheld],Location:[withheld],Violations:Crossinglinebywaytoomuchobstructingthevehicleswhichwerecomingfrom[withheld]entrancelaterhejumpedthesignal.
Admin!!CanUExplaintomerulesandregulationsfortransferringvehiclefromChennaitoBangalore?
IgnoredXXXshared NowThisFuture's video.21Februaryat10:07 · BENGALURUCITYPOLICE Interestingpieceofhandgun bullet-proof shieldindevelopment.
Acknowledge ChennaiCityTrafficPolice:ahumblesalutefromafellowChennaiite forthecommendablejobinsuchrains!!
ResearchQuestions:Serviceability� RQ1:Whatattributesdifferentiates
� Serviceablepostsfromnon-serviceablerequestsand� Sub-typesofserviceablerequestsw.r.t contentcharacteristicssuchaslinguisticandemotionalattributes?
� RQ2:Howdoespoliceresponsetimevarybetweenserviceableandnon-serviceablepostsmadeonsocialmedia?
� RQ3:Canmachinelearningtechniquesbeusedtoautomaticallyidentifyserviceablerequests� Canwefurtherclassifythemintodifferentsub-typesusingpostcharacteristics(contentandmetadata)?
40
Dataset85PublicandofficialPoliceDepartment
22,213wallposts
1000PostsannotatedbyPolice
41
PostType #Posts Likes Comments
ServiceablePosts
Forward 286 1383 661
GiveSolution 88 183 121
Thanks 72 1288 63
NeedMoreInfo. 104 1245 258
Total 550 4099 1103
Non-Serviceable
Total 113 316 32
0.77agreementusingFleissAgreement
AttributesEmotion(Alchemy&
LIWC)
States: Anger,disgust,fear,joy,sadnessValence:Positive,negative,Anxiety
Cognitive(LIWC)
CognitiveMechanism: Tentativeness andDiscrepancy
Inter-Personal(LIWC)
1stpersonsingular&plural,2ndperson,3rdpersonsingular& plural,andimpersonalpronouns
Linguistic(LIWC)
Objectivity,Tenses,LexicalDensity&Parts-Of-Speech.
QuestionAsked
(Heuristics)
who,how,why,what,where,whomandcontaininga“?”
Entities(Alchemy)
people,companies,organizations,cities,geographicfeatures,facility,dateand time
42
Attributes� TopTopicsServiceableandNon-ServiceablePostsusingLDA
43
LDAtopic VocabularyTrafficcongestion Traffic,road,signal,bus,people, turn,jamSharedphotoswebsites
com,www,facebook,https,videos,traffic,http,type,old,photos,job
Appreciation signal,great,good,taking,act,actionQuestionposed asked,rules,vehicle,sir,said,car,know, whatPlaces Telangana,state,hyderabad,city,nagar,Finesissued Challan[finecharged],violation,documentsCybercrime Police,city,cyber,crimenampally,complaint,
better,safe
Attributes� Non-negativeMatrixFactorization(NMF)fordetectingcloselyconnectedtopicsinsub-types
44
NMFtopic VocabularyPoliceincorrectdecision
Police,asked,said,constable,taken,publicwrong,driving,pay,vehicle,come,way
Awareness Don’t, mobile,rules, need,people,let,share,helmet,circle,
Dangerousdrivingcomplains
wrong,dangerous,action,driving,turn,goingjunction
Finesissued Vehicle,challan[finecharged],number,violationfine,documents,driving,guys,stopped,pay
Parkingissues Parking,people,bus,stop,parked,time,action
UsedFrobeniusNorm
RQ1:AttributesDefiningServiceability� Serviceablerequestsshowsignificantlyhighervalueofnegativeemotionalstates
45
Serviceable Non-Serviceable
Avg Std.dev Avg Std.dev Man.Anger 0.15 0.13 0.13 0.17 -3.43**Disgust 0.34 0.25 0.23 0.27 -3.88**Fear 0.24 0.21 0.15 0.18 -6.09**Sad 0.11 0.10 0.10 0.14 -5.45**
+15.38%
+60%
Presumably,emotionalstatesareexperiencedduetodistresscausedbecauseofencounterswithlawandordersituation.
RQ1:AttributesDefiningServiceability� Serviceablerequestsshowsignificantlyhigheruseof1stpersonsingularpronouns� highlyself-attention
46
Serv. Non-Serv. Frwd Give Thanks Need
1stpersonSingular**
Avg. 1.68 1.54 1.61 2.56 0.70 1.80
Sd. 2.96 9.50 2.45 3.54 2.36 3.77
Iamjustworried ifHyderabadTrafficPolice[HTP]makesthingsworselikealways
RQ1:AttributesDefiningServiceability� ServiceablepostsshowedhigherObjectivity
47
Serv. Non-Serv. Frwd Give Thanks NeedObjectivity** Avg 2.86 2.04 +40% 3.47 2.64 2.07 1.9
Sd 2.84 2.63 3.16 2.8 2.6 1.29
Serv. Non-Serv. Frwd Give Thanks Need
PastTense Avg 1.75 0.81 1.88 1.68 0.78 2.14
Sd 2.99 2.87 2.86 3.55 2.13 3.23
Serviceablepostscontainfactualinformationonwhichthepolicecanactupon.
� ServiceablepostsshoweduseofPasttense
Copsweredrivingonthewrongsidenear[withheld]hotel..whatactionwastakenagainstthem?
ResearchQuestions:Serviceability� RQ1:Whatattributesdifferentiates
� Serviceablepostsfromnon-serviceablerequestsand� Sub-typesofserviceablerequestsw.r.t contentcharacteristicssuchaslinguisticandemotionalattributes?
� RQ2:Howdoespoliceresponsetimevarybetweenserviceableandnon-serviceablepostsmadeonsocialmedia?
� RQ3:Canmachinelearningtechniquesbeusedtoautomaticallyidentifyserviceablerequests� Canwefurtherclassifythemintodifferentsub-typesusingpostcharacteristics(contentandmetadata)?
48
RQ2:PoliceResponseTime� SurvivalTime
� Timeuntil theeventofinterestoccurs
� CensoringEvent� Postswhichdidnotreceiveareplyduringourobservationperiod
� SurvivalProbability� Probability thatapostsurviveslonger thansomespecifictime(t)givenbysurvivalfunctionS(t) i.e.itdoesnotreceiveareply
49
TotalN N ofEvents Censored %Censored
Frwd 286 182 104 34.60
Give 88 53 35 39.80
Thanks 72 5 67 93.10
Need 104 60 44 42.30
Serv. 550 300 250 45.50
PoliceresponsesaremaximumforForwardSub-typeposts
RQ2:PoliceResponseTime
50
MeanEst. Sd.Error MedianEst.
Sd.Error
Frwd 1062.52 82.22 21.33 2.05
Give 1064.37 138.08 20.43 8.45
Thank 2693.14 86.42 -- --
Need 1136.31 127.48 28.26 10.45
Serv. 1326.94 61.23 33.33 --
statisticallysignificantdifferencebetweenallfour sub-typesLogRank(Mantel-Cox)test(χ2=57.03,df=3,p<0.005).
PolicereplytopoststhatcanbegivensolutionimmediatelyfollowedbyForward
� KaplanMeierEstimator
ResearchQuestions:Serviceability� RQ1:Whatattributesdifferentiates
� Serviceablepostsfromnon-serviceablerequestsand� Sub-typesofserviceablerequestsw.r.t contentcharacteristicssuchaslinguisticandemotionalattributes?
� RQ2:Howdoespoliceresponsetimevarybetweenserviceableandnon-serviceablepostsmadeonsocialmedia?
� RQ3:Canmachinelearningtechniquesbeusedtoautomaticallyidentifyserviceablerequests� Canwefurtherclassifythemintodifferentsub-typesusingpostcharacteristics(contentandmetadata)?
51
Formulation
52
RQ3:AutomaticClassificationPerformance:Costweights� Ten-foldCrossValidationPerformanceofdifferentalgorithmstocorrectlyidentifyserviceableposts.
� Contentattributessuchasemotionsandlinguisticattributesarehighlypredictiveofserviceablepostsinadditiontobag-of-wordsmodel
53
Algorithm Recall F1 Accuracy
RF 0.97 0.85 0.87
LR 0.82 0.77 0.76
ADT 0.96 0.80 0.86
DT 0.84 0.78 0.77
GBC 0.94 0.83 0.84
Attributes R2 Deviance
Emotion 0.23 437.88
Linguistic 0.19 401.83
Bag-of-words 0.53 260.07
� +Model1� Explains15.6%of thevariance� Reducesdeviancesignificantlyto1,127.58(178.14less).� Betterpredictorsaresadness,fear,andjoy.
� +Model2� Explains20%ofthevariance� 1stpersonsingularpronouns havestatisticallysignificant
54
RQ3:AutomaticClassificationPerformance
� +Model3� Explains26.3%of thevariance� Reducesdeviancesignificantlyto984.92.� Nothelpful:Tenses(presentandfuture) andlexicalterms(verbsandadverbs)
� +Model4� Explains32.4%of thevariance&devianceis902.79i.e.82.13less� Reliablepredictors:question, date,time,andentitycount� Topicdoesnothelpmuch
55
RQ3:AutomaticClassificationPerformance
ServiceabilityPlugin
56
Contributions� Identifyneedforsocialmediasupport incollaborativepolicing
� Quantifyandmineunstructureddatatoanalyze communicationattributesand
actionableinformation
� Proposeamethodtoenhance
� Policeresponsivenessusingrequest–responsedetectionframeworkandpolice
responsequantificationtoresidents
� Imagesretrievalarchitectureforimprovedcollectiveactionusingusergenerated
content
57
Challengesinsimilarimagesretrieval
58
Imageprocessing
1.Scaling
2.Cropping
3.Stitching
4.Multiple
59
DataCollectionSampleimages Event Total
imagesSimilarimages
Dissimilarimages
CharlieHebdo 568 118 450
KulkarniInk 1,905 354 1,551
InsultsHanuman 664 277 387
ShaniShingnapur 180 70 110
RamRahim 408 97 311
Imagefeaturesforsimilarity
1. Hand-CraftedFeaturesa. 3D-colourhistogramb. Daisyfeaturesc. ORB(OrientedFASTRotatedBRIEF)featuresd. ImprovedORB(ORB+RANSAC)
60
2.TrainableFeaturesa. DeepCNN(ConvolutionNeural
Network)
AlecRadford,LukeMetz,andSoumith Chintala.Unsupervisedrepresentationlearningwithdeepconvolutionalgenerativeadversarialnetworks.
OriginalImage
ModifiedImage
ImprovedORB
(%accuracy)
CNN(%accuracy)
Modification
93.7 98.3 Scaled,stitchedimage,addedtext,cropped
77.4 93.8 Cropped,stitched,text
added
84.1 99.4 Scaled(7.4✕ 5.2)
61
Competingonmodifiedimages
PicHunt
62
Contributions� Identifyneedforsocialmediasupport incollaborativepolicing
� Quantifyandmineunstructureddatatoanalyze communicationattributesand
actionableinformation
� Proposeamethodtoenhance collaboration
� Policeresponsivenessusingrequest–responsedetectionframeworkandpolice
responsequantificationtoresidents
� Imagesretrievalarchitectureforimprovedcollectiveactionusingusergenerated
content
63
Whyitmatters?� ProposeaData-DrivenTechniquetocomplementOverworkeddepartments
� Detectingpoststhatshouldelicitpoliceresponsemakesocialmediastreamsmorelistenableforresident’sconcerns
� Helppoliceimprovepolicingandresponsiveness� Takingcognizanceofprominentconstituents’concernandunsaferegionscanhelppoliceplantheirresourcesbettertoprovideimprovedsafety
� Measureresident’sreactionsinafine-grainedmanner� Information(e.g.,emotionsandinterpersonalattributes)improvetheunderstandingfromfactualinformationtoamorenuancedunderstandingofpsychological.
64
TechnologicalAdvancement� Designingearlywarningsystemsthatindicate:
� Needforemotional&socialsupportneedstoenhancepoliceresponsetoresidentsexperiencingsafetyissues.
� Afeedbacksystemonsocialmediaplatformsthatcomplementslackofphysicalsignalsofcommunication� informsaboutthelikelytimedurationtorespondtoservicerequest
� Senseandrecordthereactionsofcitizensandsharetheserecordswithdecisionmakers� Taketimelymeasuresandgainbetterinsights
65
Limitations� CulturalLimitation
� Stronghistoryofcommunitypolicingmaybehelpful
� RestrictedModality� Onlytextbasedserviceabilitydetection� Considerothermodalitiessuchasvideos,imagesetc.
� UrbanandSub-urbanResidentCommunities� Ruralareasmayhavedifferentneeds
� Causality� Analysisisbasedoncorrelations
66
67
Acknowledgement� Googlefortravelsupport
� TataConsultancyServicesforfundingthethesiswork
� Allparticipantsandpoliceofficerswhohelpedusinvariousstagesofthethesis
� Mycollaborators– specialthankstoDr.Nitesh Saxena (UAB),Dr.MunmunDeChoudhury(GaTech),Dr.IuliaIon(Google)
� MonitoringCommitteeDr.RahulPurandare,Dr.Sambuddho Chakravarty,Dr.Amarjeet Singh
� Dr.AditiGupta,Dr.Paridhi Jain,SiddharthaAsthana,PrateekDewan,AnupamaAggarwal,Srishti Gupta,Rishabh Kaushal,Anuradha Gupta
� Shrey Bagroy,Sonal Gupta,DivamGupta,Megha Arora,IndiraSen,NehaJawalkar,Bhavana Nagpal,TusharGupta,Vedant Swain
� MembersofCybersecurityEducationandResearchCentre(CERC)andPrecog whohavegivenuscontinuedsupportthroughouttheproject
� MyFamily68
Acknowledgement� Dr.Aaditeshwar Seth� Dr.CarlosCastillo� Dr.MauraConway� Dr.Ponnurangam Kumaraguru
69
Publications� PeerReviewedConferences
� Sachdeva,N.andKumaraguru,P.Online SocialMedia- Newfaceofpolicing?ASur- veyExploringPerceptions, Behavior,Challenges
forPoliceFieldOfficersandResidents.Acceptedat18thInternationalConferenceonHuman-Computer Interaction(HCII),2016.
� Sachdeva,N.andKumaraguru,P.Derivingrequirementsforsocialmediabasedcom- munitypolicing:insights frompolice.Accepted
atACM16thInternationalDigitalGovernmentResearchConference(dg.o 2015), 2015.
� Sachdeva,N.andKumaraguru,P.Online SocialNetworksandPoliceinIndia- Under- standingthePerceptions, Behavior,Challenges.
AcceptedattheEuropeanConferenceonComputer-Supported CooperativeWork (ECSCW), 2015.
� Sachdeva,N.andKumaraguru,P.Characterising BehaviorandEmotionsonSocialMediaforSafety:ExploringOnline
CommunicationbetweenPoliceandCitizens.Acceptedat30thBritishHumanComputer InteractionConference(HCI)2016.
� Goel,S.,Sachdeva,N.,Kumaraguru,P.,Subramanyam,A.,andGupta,D.PicHunt:SocialMediaImageRetrievalforImprovedLaw
Enforcement.Acceptedat8thInternationalConferenceonSocialInformatics.2016.
� Sachdeva,N.,andKumaraguru,P.SocialNetworksforPoliceandResidentsinIndia:ExploringOnline Communication forCrime
Prevention.AcceptedattheACM16thAnnualInternationalConferenceonDigitalGovernmentResearch(dg.o),2015.[Bestpaper
award].
� Sachdeva,N.,andKumaraguru,P.CallforService:CharacterizingandModelingPoliceResponse toServiceableRequestson
Facebook.AcceptedattheACMConferenceonComputer-SupportedCooperativeWorkandSocialComputing (CSCW), 2017.70
Publications� Peer-reviewedConferencePapers
� Lamba, H.,Bharadhwaj,V.,Vachher,M.,Agarwal,D.,Arora,M.,Sachdeva,N.,Ku-maraguru,P.FromCameratoDeathbed:Understanding
DangerousSelfiesonSocialMedia.11thInternationalConferenceonWebandSocialMedia(ICWSM),2017
� Mohamed,M.,Sachdeva,N.,Georgescu,M.,Gao,S.,Saxena,N.,Zhang,C.,Kumaraguru,P.,VanOorschot,P.,andChen,W.AThree-Way
InvestigationofaGame-CAPTCHA:AutomatedAttacks,RelayAttacksandUsability.Accepted at9thACMSymposiumonInformation,Computer
andCommunicationsSecurity(ASIACCS),2014.
� Sachdeva,N.,Saxena,N.,andKumaraguru,P.OntheViabilityofCAPTCHAsforUseinTelephonySystems:AUsabilityFieldStudy.16th
InformationSecurityConferenceNovember2013inDallas,Texas(ISC),2013.
� Sachdeva,N.,Saxena,N.,andKumaraguru,P.OntheViabilityofCAPTCHAsforUseinTelephonySystems:AUsabilityFieldStudy[Poster].
(APCHI)2013
� Ion,I.,Sachdeva,N.,Kumaraguru,P.,andCapkun,S.Homeissaferthanthecloud!privacyconcernsforconsumercloudstorage.InSymposium
onUsablePrivacyandSecurity(SOUPS)(2011).
� JournalPapers
� Manar Mohamed,SongGao,Niharika Sachdeva,Nitesh Saxena,Chengcui Zhang,Pon- nurangam Kumaraguru andPaulvanOorschot.Onthe
SecurityandUsabilityofDynamicCognitiveGameCAPTCHAs.InJournalofComputerSecurity(JCS),2017.
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Thankyou!niharikas@iiitd.ac.in
http://precog.iiitd.edu.in/