Logging in Digital Libraries

Last week …. Introduction to quality indicators and the way in which these are formalized and made computable, according to one view. Making a digital library as good as it cam be requires understanding what it is and how it is being used. Information comes from logs

Another aspect A category of quality indicator that comes from seeing what happens when users visit the library An important tool -- the logs All web based systems have logs of interaction from the outside world to the web server –Not specifically designed for digital libraries We will look at a proposed standard for digital library specific log analysis

This work Done by Marcos André Gonçalves, Ming Luo, Rao Shen, Mir Farooq Ali, and Edward A. Fox - Virginia Tech and Lillian N. Cassel, Filip Jagodzinski - Villanova

Motivation Log analysis Source of information about: How patrons really use DL services How systems behave while supporting user information seeking activities Examples: patterns Used to: Evaluate Enhance services Help design user interfaces Better allocation of resources Common practice in the web setting Supported by web servers, proxy caching

Motivation (cont.) DLs differ from the web –DL collections are explicitly organized, described, managed, and preserved –Users with more specific tasks and needs –Digital objects and collections more structured  DL Logging should offer much richer information and opportunities  Tradeoff : user privacy Current DL logs –Differences in formats and recorded information –Problems: Lack of interoperability No reuse of analysis tools Comparability of log analysis results

Related Work Problems with existing DL logs –Incompatibility –Incompleteness –Complexity of analysis –Lack of organization –Ambiguity –Inflexibility –Verboseness --- Generally, lack of a global view of need for understanding how the DL is or is not serving its users

The Digital Library Standardized Log Format Comprehensive Reflective of the actual DL system behavior Easily readable Precise Flexible to accommodate varying systems Succinct enough to be implemented Concern: user privacy

DL Standarized Log Format Design Capture high level user and system behaviors –Hierarchical organization –Encapsulated in transactions Interactions between the users and the system or among the system components Log format designed to record a number of different kinds of transactions Examples:  Login to the system  Submission of search query  Browsing a result list  Recording of a user failure

Log format design (cont.) Design –Reflective of DL function –Based on the 5S formal theory Unifying, mathematical theory to describe formally the semantics of DL components Guidance for how to organize the log structure

Log design and 5S 5SDefinitionUse in Log Design StreamsRepresent static and dynamic multimedia content StructuresLabeled directed graphs; provide organization within the DL SpacesSets, properties and operations on those sets Scenariossequences of events that modify states of a computation in order to accomplish some functional requirement. SocietiesSets of communities and relationships among them

Log design and 5S 5SDefinitionUse in Log Design StreamsRepresent static and dynamic multimedia content Temporal events, types of digital objects StructuresLabeled directed graphs; provide organization within the DL SpacesSets, properties and operations on those sets Scenariossequences of events that modify states of a computation in order to accomplish some functional requirement. SocietiesSets of communities and relationships among them

Log design and 5S 5SDefinitionUse in Log Design StreamsRepresent static and dynamic multimedia content Temporal events, types of digital objects StructuresLabeled directed graphs; provide organization within the DL Structured documents and metadata; structured searches, collection, metadata catalog; hypertext, classification scheme SpacesSets, properties and operations on those sets Scenariossequences of events that modify states of a computation in order to accomplish some functional requirement. SocietiesSets of communities and relationships among them

Log design and 5S 5SDefinitionUse in Log Design StreamsRepresent static and dynamic multimedia content Temporal events, types of digital objects StructuresLabeled directed graphs; provide organization within the DL Structured documents and metadata; structured searches, collection, metadata catalog; hypertext, classification scheme SpacesSets, properties and operations on those sets Retrieval mode, Presentation information, Scenariossequences of events that modify states of a computation in order to accomplish some functional requirement. SocietiesSets of communities and relationships among them

Log design and 5S 5SDefinitionUse in Log Design StreamsRepresent static and dynamic multimedia content Temporal events, types of digital objects StructuresLabeled directed graphs; provide organization within the DL Structured documents and metadata; structured searches, collection, metadata catalog; hypertext, classification scheme SpacesSets, properties and operations on those sets Retrieval mode, Presentation information, Scenariossequences of events that modify states of a computation in order to accomplish some functional requirement. Organization of the user and system actions into transactions, statements, events and actions; DL services as sets of scenarios. SocietiesSets of communities and relationships among them

Log design and 5S 5SDefinitionUse in Log Design StreamsRepresent static and dynamic multimedia content Temporal events, types of digital objects StructuresLabeled directed graphs; provide organization within the DL Structured documents and metadata; structured searches, collection, metadata catalog; hypertext, classification scheme SpacesSets, properties and operations on those sets Retrieval mode, Presentation information, Scenariossequences of events that modify states of a computation in order to accomplish some functional requirement. Organization of the user and system actions into transactions, statements, events and actions; DL services as sets of scenarios. SocietiesSets of communities and relationships among them User information

DL Log Format Specification Organization in structured logical way –XML- XML Schema Standard syntax Guarantee quality, correctness Rich set of basic types help standardization Abundance of XML parsers helps construction of analysis tools

Log Format - Structure Top Level Hierarchy Log Log Entry Transaction SessionId MachineInfo TimeStamp Statement...

DL Log Format - Structure (cont) Decomposition of statement into different types AdmInfo Statement SessionInfo Event ErrorInfo HelpInfo RegisterInfo

Log Format - Structure (cont.) Decomposition of event AdmInfo Statement SessionInfo Event ErrorInfo HelpInfo RegisterInfo Action StatusInfo SearchBrowseStoreSysInfo Update

DL Log Format Structure (cont) Search attributes Search QueryString TimeFrame PresentationInfo SearchBy FormatNumberOfResultsSortBy CutOff Collection Catalog

DL Log Tool Implementation Digital Library User Layer XMLLogManager writeLogEntry (parameters) c1 XMLLogData c2 Log middleware System event storelogData (parameters) User event Analysis tool getLogData (parameters) logData Analysis request result DL patron DL analyst

Log Tool example: login Example 1: Login to the system usr3 Start mhabib T20:10: :

Log tool example: query a collection Example 2: query all Dirline records about “low back pain”.. Dirline CommunityRecord SearchByAnyParts NonPersistant low back pain T20:11: : T20:11: :00 List ByRank Ref to GMT

Log Analyzer Overview XML Log Log Data Parser/ Error Checker Routine module usr T20:10: … low back pain … 5114 Step 1: Extract Browse Query StringUser ID SearchError Doc ID Step 3: Populate Databases, Increment Global Variables, etc. Step 4: Create Final Statistics module module Step 2: Parse XML; Send Log Line Final Report/ Statistics Databases Step 1: Extract Log Data, SAX parser can be employed here Step 2: Parse Log Data and check for log errors (eg. server stalls and incomplete log line is output to XML Log) Step 3: The different modules populate various databases and/or increment the appropriate counters. Each module can adjust various databases, as for example the module, which increments the appropriate month hit counter and records that the user usr3 made a request at time T. Step 4: Aggregate data and output final statistics; all databases are made available

Summarizing this class and last week Looked at a view of DL quality –By examining the components of the DL independent of usage (explicit computation) –By looking at the view of the DL obtained by a visitor (log analysis) Each is a view that has been widely promulgated and well received, but is not an industry standard

Next week Joseph Lucia, Director of Villanova’s Falvey Library will talk about what is happening in this very innovative and significant digital library. Come prepared with questions and ready to comment and discuss what he presents.

References Gonçalves, M. A., Luo, M., Ali, M. F., and Fox, E. A. “An XML Log Standard and Tool for Digital Library Logging Analysis” In Research and Advanced Technology for Digital Libraries, 6th European Conference, ECDL 2002, Rome, Italy, September , 2002, Proceedings Klas, C., et al "A Logging Scheme for Comparative Digital Library Evaluation” Research and Advanced Technology for Digital Libraries, 10th European Conference, ECDL 2006, Alicante,Spain, September 17-29, 2006, Proceedings