Brown, Peter J.

Jones, Gareth J.F.

English

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SIGIR 2004 IRiX Workshop 29th July 2004 1The Role of Context in Information RetrievalGareth J. F. JonesSchool of Computing, Dublin City University, IrelandPeter J. BrownDepartment of Computer Science, University of Exeter, U.K.SIGIR 2004 IRiX Workshop 29th July 2004 2OverviewDefinitions of Context for Information RetrievalInformation Retrieval in Context (IRiX)Context in Current IR SystemsContext in Mobile and Ubiquitous Information Access– Context-of-InterestContext in IR AlgorithmsConcluding ThoughtsSIGIR 2004 IRiX Workshop 29th July 2004 3Definitions of Context for Information RetrievalInformation Retrieval (IR): location and delivery of documents whichsatisfy a user information need.IR takes place in “context”, but this context is generally ignored in IRmodels and system design.The definition of context in IR is widely interpreted (“abused”(Finkelstein et al. 2002)).SIGIR 2004 IRiX Workshop 29th July 2004 4Definitions of Context for Information RetrievalDoes/Should context in IR relate to:user tasks?interactive searching?domain specific searching?personalization in search?physical context as measured by environmental sensors?SIGIR 2004 IRiX Workshop 29th July 2004 5Definitions of Context for Information RetrievalIR has conventionally been concerned with users in an “informationworld” using a desk-based IR system.- concerned with cognitive contextWireless networks are providing IR possibilities users embedded inthe “real/physical world”- concerned with cognitive and physical contextSIGIR 2004 IRiX Workshop 29th July 2004 6Information Retrieval in Context (IRiX)Does IRiX imply interactive IR?Is all IR interactive IR?Does context have to come from the user?Does/Should IRiX encompass all forms of context informationwherever it can be found in the IR process?SIGIR 2004 IRiX Workshop 29th July 2004 7Information Retrieval in Context (IRiX)USER’S MODEL OFSEARCH ENGINEPHYSICAL CONTEXT− location, time, associates, ...USER’S OVERALL CURRENT TASKUSER’S KNOWLEDGEUSER’S OTHER TASKSUSER’S MODEL OF INFORMATIONSEEKINGRELEVANCEFEEDBACKINDEXFILEINFORMATION NEEDRETRIEVED DOCUMENTSUSER’S SEARCH QUERYTypical interactive IR scenario.SIGIR 2004 IRiX Workshop 29th July 2004 8Information Retrieval in Context (IRiX)INDEXFILEUSER’S SEARCH QUERYRETRIEVED DOCUMENTSTypical IR scenario without considering context.Is this an interactive IR scenario as well?SIGIR 2004 IRiX Workshop 29th July 2004 9Context in Current IR SystemsAny information from the user can be regarded as some form ofsearch context data.- including the query?A typical IR system assumes:indexing units (words, attributes) are independent.independent indexing units appear in the context of other oneswithin documents.relevance feedback (RF) implicitly makes use of indexing unitcontext.- indexing units are in the context of relevant documents.SIGIR 2004 IRiX Workshop 29th July 2004 10Context in Current IR Systemsthe IR system models the importance of indexing units in thecontext of relevance information.- can be used to expand the query.pseudo or blind RF has no user feedback.- relevance context is inferred from ranking of initial retrieval run.location context of indexing units within documents can be takeninto account as part of the expansion process.SIGIR 2004 IRiX Workshop 29th July 2004 11Context in Mobile and Ubiquitous Information AccessPortable networked devices means that users have access to IRapplications while engaging in their everyday lives.Studies conclude that:user is likely often to be engaged primarily in other activities.user will desire information relevant to their current cognitive andphysical context.there are limited possibilities for interaction and browsing.there is potential to user physical context to improve IR in thisenvironment.SIGIR 2004 IRiX Workshop 29th July 2004 12Context in Mobile and Ubiquitous Information AccessPhysical context data can be made available via personal andenvironmental sensors.Some context information can be used directly, e.g. current location.Other may need to be aggregated, e.g. to decide on audio informationdelivery while the user is driving.SIGIR 2004 IRiX Workshop 29th July 2004 13Context in Mobile and Ubiquitous Information AccessContext-of-InterestHypothesis: mobile users will often be interested in informationrelating to context just ahead of their current context.Solution: predict their future context and retrieve based on this ratherthan the current context.context-diary - the past (what happened), present (what ishappened), and expected future (planned, observed)personal profilesRank scoring of potentially relevant document set may change withcontext.SIGIR 2004 IRiX Workshop 29th July 2004 14Context-of-InterestUSERDIRECTION OF MOTIONstate at time tCurrent state of user and potentially relevant documents at time .SIGIR 2004 IRiX Workshop 29th July 2004 15Context-of-InterestUSERDIRECTION OF MOTIONstate at time t+1State of user and potentially relevant documents at time   .SIGIR 2004 IRiX Workshop 29th July 2004 16Context-of-InterestUSERDIRECTION OF MOTIONcontext state at time t+1, user state tCurrent state of user at time , state of potentially relevant documentsat time   . Predict user context at time   - may not be correct!SIGIR 2004 IRiX Workshop 29th July 2004 17Context in Mobile and Ubiquitous Information AccessPro-activeness and Autonomyuser is busy, engaged in other activities.user may be unaware of available information potentially relevantto their context.user context with personal profiles to perform pro-activesearching.Elements of information filtering and IR.SIGIR 2004 IRiX Workshop 29th July 2004 18Context-Aware RetrievalFILTERINGSYSTEMINFORMATIONPROFILE(S)DOCUMENT TO USERDOCUMENTSFEEDBACKYES/NOInformation filtering with profile adaptation via feedback.SIGIR 2004 IRiX Workshop 29th July 2004 19Context-Aware RetrievalFILTERINGSYSTEMINFORMATIONPROFILE(S)DOCUMENT TO USER+USERCONTEXTDOCUMENTSFEEDBACKYES/NO+CONTEXTInformation filtering with profile adaptation via feedback withdocument and profile context fields.SIGIR 2004 IRiX Workshop 29th July 2004 20Context-Aware RetrievalPROFILE(S)+USERCONTEXTAWARERETRIEVALCONTEXT−+CONTEXTINDEXFILEDOCUMENTFEEDBACKYES/NODOCUMENTSTO USERContext-aware retrieval, change in user context or documentsrequires pro-active IR/IF with profile adaptation via feedback.SIGIR 2004 IRiX Workshop 29th July 2004 21Concluding ThoughtsWhat should be the scope of IR in Context?Context in some form appears at many levels stages within an IRsystem?Physical context is an important aspect of mobile computingsystems.– How can we make use of this for mobile iR?Can we usefully extract context information from documents andqueries to enhance the effectiveness of retrieval algorithms?Related field merging issues in multimedia IR, genomic IR,geographic IR.

The role of context in information retrieval

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The role of context in information retrieval

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