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					    Granular Computing for the Design of
    Information Retrieval Support System



Y.Y . Yao
Dept of Computer Science
University of Regina


                           Presented by Mohamad Seif
                           Dept of Computer Science
                           UNCC
                           11/24/2008
            Presentation Overview
 IR   systems used as a tool for searching for relevant information.

 Current    IR systems & challenges:
      Focus on the retrieval functionality
      Do not understand the meaning of user query & document contents .
      Translating info needs into queries.
      Matching queries to stored information

 We need new generation of IR that support user tasks in finding
 & utilizing information.

 IRSS    is the potential solution:
      Framework that support scientific research.
      Provides models, tools, utilities to allow the user to explore both semantic
       & structural information of each document.
                      IR Situation
    The three components, user, resource, and intermediary and
    their interactions with one another , together constitute the
    Information Retrieval System(IR).




      User              Intermediary           Resource
                             IR

 Information  retrieval is a communication process, by which
 users of information system can find information that matches
 their needs ((solve a problem, make a decision).)

 IRgoal is to provide, identify, and rank useful documents from
 a large collection of documents.
                    IR(Cont)
 Conceptually,  IR is used to cover all related
 problems in finding needed information.

 Historically,   IR is about document retrieval.

 Technically,IR refers to (text) string
 manipulation, indexing , matching, querying,
 etc.
                              IR(Cont)
 What     do we retrieve?

              Data
              Information
              Knowledge

    Data does not have meaning of itself, data items need to be part of a
    structure like a sentence to give them meaning.

 Information: The meaning of the data interpreted by a system or
    person. It adds context and meaning to the data.

 Text: Strings of ASCII symbols. If understood it’s information.

 Documents: logical unit of text (articles, books, web pages).
                      IR & DR
Information retrieval vs. Data retrieval

                      Data Retrieval      Information Retrieval
Content               Data                Information
Data Object           Table               Document
Matching              Exact               Partial
Items Wanted          Matching            Relevant
Query Language        SQL                 Natural
Model                 Highly Structured   Less Structured
Query Specification   Complete            Incomplete
                       IR & WWW
 The    WEB, digital libraries, and markup languages are new
    challenges to IR researchers.

 The WEB has significant impact on academic research,
 however making effective use of it is a challenge for
 scientists.

 Many    of Search engines inherit disadvantages of traditional
    IR systems.
                          IR Limitations
   Current IR limitations

        IR focus mainly on the retrieval functionality. There is little support for
         others activities of scientific research.

        Does not attempt to understand the “meaning” of user’s query (because
         users use very few terms in search queries ).

        Does not inform the user on the subject of his inquiry. It merely informs on
         the existence or non-existence of documents related to his request.

        Current IR techniques are unable to exploit the semantic knowledge within
         documents and hence cannot give precise answers to precise questions.


        IR use simple pattern based matching to identify documents
                      IR & IRSS

   IR are not sufficient to support research on the new WEB
    platform.

   So we introduce IRSS (Information Retrieval Support
    System) framework for supporting scientific research.

   IRSS is a framework for supporting scientific research.

   IRSS provides models, tools, and functionalities.
                Granular Computing
   The concept of GrC originally called information granulation.

   The term is first used in 1996-1997.

   Granulation seems to be natural problem-solving methodology
    deeply rooted in human thinking.

   Human body granulated into head, neck, …etc, so the noting is
    fuzzy and vague.

   Granulation involves partitioning class of objects into granules.

   GrC deals with representing information in the form of aggregates
    (embracing a number of individual entities) and their processing.

   GrC is knowledge-oriented (data mining ).
              Information Granules
   IG arise in the process of data abstraction and derivation of
    knowledge.

   IG Are collections of entities. They are arranged together due
    to their similarity, functional adjacency, coherency or alike.

   An image of any landscape consists of trees, houses, roads,
    and lakes. All these objects are generic information granules.

   The level of information granulation depends on the problem
    at hand and the need of the decision-making process. With
    the big view of the world we deal with large granules
    (continents and countries). When more details are required
    we move down to regions, provinces, and states.

   Information granulation: process of constructing granules.
                   GrC Components
   Granules (Description):

       A granule may be interpreted as one of the numerous
        small particles forming a larger unit.

            In set theory: a granule may be interpreted as a subset of a
             universal set.

            In planning: a granule can be a sub-plan .

            In programming: a granule can be a program module

       The size of a granule is considered as a basic property.
        Intuitively, the size may be interpreted as the degree of
        abstraction, concreteness, or detail.
               Components of GrC
   Granules (Relationships):

        Connections and relationship between granules can be represented
         by binary relations. In concrete models, they may be interpreted as
         dependency.
        For example, based on the notion of size, one can define an order
         relation on granules. Depending on the particular context, the
         relation may be interpreted as “greater than or equal to” or “more
         abstract than”.

   Granules (Operations):

        Combining many granules to form a new granule
        Decomposing a granule into many granules.

    The operations on granules must be consistent with the binary relations
    on the granules. For example, the combined granule should be more
    abstract than its components
                      GrC Components
   Granules views & Levels
       A level consists of a family of granules that provide a complete
        description of a real world problem, or theory, or design or plan.

       Each entity in a level is a granule.

       Level = Granulated view = a family of granules

       Granules in a level are formed with respect to a particular degree of
        granularity or detail.

       Multiple levels of granularity in any technical writing:
          High level of abstraction
            title, abstract
          Middle levels of abstraction
            chapter/section titles
            subsection titles
          Low level of abstraction
            text
                GrC Components
   Granules (Hierarchies)
     A hierarchy may be interpreted as levels of abstraction,
      levels of organization, and levels of detail.

       Granules in different levels are linked by the order
        relations and operations on granules.

       A higher level (Generalization) may provide constraint to
        and/or context of a lower level (Specialization).

       A granule in a higher level can be decomposed into
        many granules in a lower level.

       A granule in a lower level may be a more detailed.
                           Granulation
   Granulation: Construction & Decomposition of granules.

        Granulation criteria :Why two objects are put into the same granule?
        Granulation methods: How to put objects together to form a granule?

   Granulation involves the process of 2 directions in problem
    solving:
        Construction involves the process of forming a larger and higher level
         granule with smaller and lower level granules that share similarity and
         functionality , based on available information and knowledge.

        Decomposition is the process of dividing a larger granule into smaller and
         lower level granules , based on available information and knowledge.
                               IR
   IR deals with the representation, storage, organization of,
    and access to information items.

   IR designed to identify and rank useful items from a stored
    information in response to user request.

   Scientists use IR as an effective tool to find relevant
    information
                          IR Basic Issues
   Three fundamental issues in information retrieval:

        Document representation (logical view of the documents).
          •   Documents represented as list of words based on limited statistical analysis.
              We need to consider the semantic information of the document.

        Query formulation (translation).
          •   Query might be too Restrictive or too complicated.
          •   A user is not clear what is being searched for.

        Retrieval functions.
          •   Retrieval based on keyword level matching .
          •   Documents containing the keywords appearing in the query are retrieved or
              ranked higher. Other information that may suggest the relevance of documents
              is not fully explored.
    Document Space Granulations
   Document clustering is a technique to reduce computational costs
    and improve retrieval effectiveness.

   Clustering ways

        Content based: Documents with similar content or topic are put into
         the same cluster.

        Query based: documents are put into the same cluster if they tend to
         be relevant at the same to some queries.

        Citation based : Such clustering methods are used in Research Index,
         in which, for example, co-cited documents are put into a cluster

        Document can be clustered based on authors and journals.
            Query Space Granulations

   Like the granulation of document space, one can construct
    granulated views of query space in several ways:

        Content based
         It is similar to content based document clustering. The similarity of
         queries is evaluated based on index terms used by the queries.
         Similar queries are grouped together to represent the needs of a
         group of users. Content based approaches can be easily extended to
         cluster users based on user profiles or user logs.

        Document based
         This method uses the overlap of relevant documents, retrieval results,
         of queries.
        Unified Probabilistic Model
   The relevance of documents to queries is modeled
    in probabilistic terms. Its 4 sub-models are:

       Model 1: based on the granulation of query (user) space .

       Model 2: based on the granulation of document space.

       Model 3: (no granulation) represents the ideal situation where the
        relevance of individual documents to individual queries is used.

       Module 4 (combination of Model 1 & 2 ):
        More specifically, the relevance of a particular document to a
        particular query is estimated by the relevance of the document to a
        group of queries and the relevance of a group of documents to the
        query.
Retrieval Results Granulations
   IR systems return list of document that is too long and
    duplicate. So we need clustering to organize the result.

   Granulating retrieval results referred to as query specific
    document classification.

   An important issue in query specific document clustering is
    to obtain a meaningful description of the derived clusters to
    be presented to the user.

   It has been suggested that a few titles and some terms can
    be used as the description of a cluster . One may also
    extract some important sentences from the documents in a
    cluster as a description of the cluster.
Structured and XML Document
   The document level structure information can be obtained
    from the use of markup language.

   In XML, the structures and the meaning of data are explicitly
    indicated by element tags. The structure of a document and
    element tags are defined through a DTD .

   In XML one can cluster documents using certain tag fields.

   One may use structured queries by focusing on certain tags
    or perform free text retrieval by simply ignoring all tags.
                          DRS to IRS
   DR may be considered as an early stage, and IRS as the next evolutionary
    stage in the development of retrieval systems.

   Both DR and IR focus on the retrieval functionality, namely, the match of
    items and user information needs.

   The differences between DR and IR can be seen from the ways in
    which information items and user information needs are represented, as well
    as the matching process.

   In DR data items and user needs are precisely described, in IR
    is the opposite.

   DR deals with structured problems, IR deals with semi-structured problems.
                        IR User Tasks
   There are 2 different types of user tasks when using IR
    system:

        A retrieval task
          Performed by translating an
         information need into a query and searching using the query.

        A browsing task
          Looking around in a collection of documents through an interactive
         interface. During browsing the user information need or objective may not be
         clearly defined, and can be revised through the interaction with the system.
                           IR to IRSS
   IR have important role in the success of the web, however can still be
    viewed as document retrieval

   IR provide the basic search and browsing functionalities.

   The next generation of IR systems must support more types of user
    tasks (better understanding), in addition to searching and browsing.

   A new set of principles for the design and implementation of
    the next generation IR systems is needed.

   The evolution of retrieval systems leads to the introduction
    of IRSS (Information Retrieval Support System).
                                 IRSS
   IRSS supports user tasks in finding and utilizing information.

   Techniques and principles from DSS (Decision Support System)
    are applicable to IRSS by substituting “decision making” for
    the tasks of “information retrieval”

   Features of DSS:
        Combination of data & models: Models to make sense of the raw
         data. Therefore DSS deals with both data & their interpretation.

        User involvement: An DSS plays a supporting role in problem
         solving.

   Retrieval problem: Finding information from documents are
    unstructured problems and it is more complicated if the user might not
    know exactly what being searched for.
                 IRSS Characteristic
   IRSS provides models, languages, utilities, and tools to allow the user to
         explore both semantic and structural information of each document as
         well as the entire collection.

   IRSS Models:
        Document models: deal with representations & interpretation of
         documents and the document collection.

        Retrieval models: deal with the search. A user can choose different
         retrieval models with respect to different document models.

        Presentation models: deal with the representation and interpretation
         of results from the search. A user views and arrange results by using
         distinct models.

   The main function of IRSS is to support a user.
                IRSS Components
   Data management subsystem
    Deals with raw data management using DBMS.

   Model Management Subsystem
    For analyzing & interpreting the raw data and to build user models.

   Knowledge-based Management subsystem
    Supports other subsystem and provides intelligence to a decision maker.

   User Interface Subsystem
    Handles the interaction between user & the system
A GrC Model for Organizing & Retrieval
         XML Documents
   The granulated representation of an article is the document
    level granulation.

   The collection level granulation “ seek relationships between
    individual XML documents. A tag or more may be used to
    form granules. Document might be grouped and divided.

   Building hierarchal granulation: at each level the same
    documents is represented differently.

   The granulation of the collection enables the user to
    understand structural information about the collection.

   In GrC model: 3 basics types of operations support the user
        Creation of logical views, navigation through different logical views, and
         retrieval.
                        Conclusion
We discussed:

      The application of granule computing to information retrieval.

      The introduction of Information Retrieval Support Systems (IRSS).
Questions & Answers
Thank You !

				
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posted:5/1/2011
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