1. WebTrails Jure Leskovec University of Ljubljana, Slovenia Internship at MSR (Aug 1 – Sept 31, 2001)

2. Outline Problem statement Our approach Demo

3. Problem 1: History Navigation Insufficient support for navigation over seen pages  One step linear navigation (back/forward)  Lost parts of navigation (inaccessible pages) ABCD FE

4. Problem 2: Search Poor search facility in Internet Explorer  No visual clues  Inflexible results sorting  No navigation information

5. IE History Navigation

6. IE History Search

7. Objectives Enhance the history with navigation information Provide easy access to the seen pages  Recent history  in-session navigation support tool  Whole history  search over all seen pages

8. Proposed Solution Easy access to a page seen in the current browsing session - Session Navigator  Visual clues – Thumbnails of accessed pages  Navigation Trails - Grouping pages based on navigation Whole history search:  Time query  Text query (content, query, link)  Colour scheme (position of colours on the page)

9. WebTrails Definition: Sequence of traversed pages started by entering a search query typing a URL and generated by following links using back/forward buttons using the Session Navigator.

10. Captured Data For each page the WebTrail contains: Page URL Body text Page type  Accessed by following a link  Opened in a new window  Typing in a URL  Typing a search query (search result page)  Back/forward navigation Time Referring page (parent)

11. CDEA Session Navigator Trail building and GUI presentation A FE D ADDEC B AB C BF Linear TrailNavigation Tree Flattening the graph to a linear sequence of tree branches Time ordered Cursor indicating the current page Trail building and GUI presentation

12. Session Navigator (2) Trail usage  Reviewing seen pages  Random access to a page to continue browsing (add already viewed page if navigating further away from the page)

13. WebTrail Graph

14. Search Search over colour schemes of thumbnail images  Assumption: people remember position of highly distinct or predominant colours on the page Visual clues – Thumbnails and WebTrails in the search results

15. Thumbnail Analysis Partitioning thumbnails into regions Assigning a single colour per region  Histogram analysis  Colour clustering

16. Histogram colour merging Left Right Body

17. Colour Clustering Colour Spaces  3d space – RGB, HSL, CIELab Red Blue Green

18. Red Blue Green Color Similarity RGB color space, Euclidean distance 60 RGB Space

19. Colour Clustering (2) Problem: Define colour distance measure so that colours similar by human perception are close in distance Red Blue Green RGB Space

20. Colour Clustering (2) RGB HSV Colour set Red Blue Green Hue Saturation Value RGB Space HSV Space Solution: 2 step colour merging 1. Conservative merging in RGB space 2. Further merging in HSV space Colours in the union of two neighbourhoods are merged

21. Colour Clustering (3) Benefits:  Flexible colour palette selection Applying different threshold on the distance

22. Colour Palettes 15 colour palette 25 colour palette Automatically generated from the collection of thumbnails

23. Colour Clustering (3) Benefits:  Flexible colour palette selection Applying different threshold on the distance  Simplified description of the page By reducing the number of colours on the page representation  Human friendly colour distinction Reducing the fine variability in colours

24. Thumbnail Clustering Clustering thumbnail colour schemes  Hierarchical clustering based on colour position  Off-line (at the moment) Useful for  Query by example  Browsing through navigation history

25. WebTrails 0.1 DEMO