1. To See, or Not to See—Is That the Query? Robert R. Korfhage Dept. of Information Science University of Pittsburgh 1991 Reviewed by Yi-Bu Chen LIS 551 Information Retrieval March 23, 2004

2.  Problems of traditional IR systems  Visual information retrieval system I -- GUIDO  Underlying model  How it works  Problems and development  Visual information retrieval system II -- VIBE  Underlying model  How it works  Problems and development  Conclusions Overview

3. Problems of Traditional IR Systems In responding to a user’s query, the traditional IR systems return with sequential list of documents:  The documents may or may not be ranked by relevance.  Even if ranked, users do not know how the relevance is determined by the systems.  Preventing users from viewing of other documents, and with no or little relevance feedback, they hinder users’ query reformation process.  The sequential list does not give users a clear and comprehensive view of all the documents retrieved.  Little or no efforts to take into account user individuality.

4. The Questions Raised  How to present to users a complete view of the document space so that  Users are not limited away from the documents the systems deem less relevant;  Users are able to see significant relationships among the documents.  How to enable users to browse and navigate large document spaces with ease ?  How to facilitate users’ query reformation process?

5. GUIDO: Graphical User Interface for Data Organization The underlying model--the vector space model  A document collection is viewed as a multidimentional space whose dimensionality is determined by the number of vocabulary terms.  The vectors of the queries are reference points called points of interests (POI), against which each document is measured.  A Document is represented by a point whose coordinates are its absolute distances from each POI.  Similarity of a document to a POI is measured by the absolute distance (numerical values) between the two vectors.

6. GUIDO: 1, 2, and 3 POIs  With a single POI (query), GUIDO display in one-dimentioal just like many traditional IR systems.  With 2 POIs, the distance space (document space) is a half- infinite plank.  With 3 POIs, the distance space is a 3-dimentional prism.  GUIDO is most useful for 2 and 3 POIs or reference points. Fig. 2 The GUIDO space with 3 POIs Fig. 1 The GUIDO space with 2 POIs

7. GUIDO: A 2-POI example  Document icons located lower in the plank have higher similarity to both POIs than those further out.  All documents having the same distances from both POIs appear at the same single position. Fig. 3 The GUIDO space with 2 POIs, with distances measured using 3 different metrics (the city block metric; the Euclidean metric, and the maximal distance metric.)

8. GUIDO: Browsing and Retrieval  Four models of combining distances for retrieval evaluation have been proposed.  Once a model is chosen, a cap is formed. Documents below the cap will be retrieved.  Placing the cap near the bottom of the plank sets a higher threshold for retrieval. Fig. 4 The GUIDO space with 2 POIs, capped with four different retrieval models (disjunctive, conjuctive, elliptical and Cassini oval).

9. GUIDO: Redefining the Display  Documents unrelated to the POIs are hidden.  By changing POIs, new document spaces can be generated. (query reformulation)  Four ways of creating new POIs:  Modify the weights of the terms in an existing POI  Combine given POIs into a new one  Select a particular document to be a POI  Calculate a new POI from an interesting cluster of the documents by a simple cluster analysis.

10. GUIDO: Problems and Future Directions  Loss of information in changing from document space model to the distance space model.  Document space model: only documents with identical descriptors mapped into the same point.  Distance space model: any documents whose distances to various POIs are same mapped into the same point.  Inter-document distance is not represented.  Integrate GUIDO with other visual interfaces (such as BIRD which is based on the Boolean model) to create a more complete document handling system.

11. VIBE: VIsualization By Example  Developed by Olsen et al. (1991) on the basis of the same distance paradigm as GUIDO, with further reduction of dimensionality.  A document collection is viewed as a TWO dimensional space.  The POIs can be positioned anywhere (NOT fixed as in GUIDO), and users can define as many POIs as wanted.  A Document is represented by a point whose coordinates are the RATIOS of its distances from each POI (NOT the absolute distances as used in GUIDO).

12. VIBE: An Example

13. GUIDO Vs. VIBE  POIs are fixed, 2-3 are the most useful.  POIs can be modified.  Document position determined by the absolute distances to each POI.  Position of a document indicates the strength of each POI with respect to the document.  Loss of information as different documents with the same distances to each POIs are mapped to the same point.  POIs are NOT fixed, 3 or more are the most useful.  POIs can be modified AND moved.  Document position determined by the ratios of the distances to each POI.  Position of a document indicates the relative strength of each POI with respect to the document.  Icon size proportional to the strength of the most significant POI.  Further Loss of information as different documents with the same ratios of the distances to each POIs are mapped to the same point.

14. VIBE: Recent development

15. Conclusions  Both GUIDO and VIBE provide users with full visibility of a document set of large size and allow them to control the retrieval dynamically.  Both GUIDO and VIBE permit users to modify POIs and view the instant impact of document space by such modifications, therefore greatly facilitate query reformulation process.  Unlike the traditional IR systems, GUIDO and VIBE enable users to browse the database and determine the relevance of a document before its retrieval.  Limitations in displays will need to be resolved before GUIDO and VIBE can go mainstream.

16. Additional Readings  Korfhage RR and Olsen KA, 1991. Information display: control of visual representations. IEEE.  Nuchprayoon A and Korfhage RR, 1994. GUIDO, a visual tool for retrieving documents. IEEE.  Korfhage RR and Nuchprayoon A, 1997. GUIDO: visualizing document retrieval. IEEE.  Morse E, Lewis M, and Olsen KA. Testing Visual Information Retrieval Methodologies Case Study: Comparative Analysis Of Textual, Icon, Graphical And “Spring” Displays. Manuscript on the web.