CS 430: Information Discovery

1. CS 430: Information Discovery Lecture 17 Usability 2

2. Course Administration Assignment 2 Last grades and replies to queries will be sent out this evening. Assignment 3 The assignment has been posted. A hint and some minor wording changes will be posted this evening.

3. Levels of Usability interface design functional design data and metadata computer systems and networks conceptual model

4. Conceptual Model The conceptual model is the user's internal model of what the system provides: • The desk top metaphor -- files and folders • The web model -- click on hyperlinks • Library models search and retrieve search, browse and retrieve

5. Interface Design The interface design is the appearance on the screen and the actual manipulation by the user • Fonts, colors, logos, key board controls, menus, buttons • Mouse control or keyboard control? • Conventions (e.g., "back", "help") Example: Screen space utilization in American Memory page turner.

9. Disabilities • What if the user: is visually impaired or color blind? does not speak English? is a poor typist?

10. Functional Design The functional design, determines the functions that are offered to the user • Selection of parts of a digital object • Searching a list or sorting the results • Help information • Manipulation of objects on a screen • Pan or zoom

11. Same functions, different interface Example: the desk top metaphor • Mouse -- 1 button (Macintosh), 2 button (Windows) or 3 button (Unix) • Close button -- left of window (Macintosh) right of window (Windows) Example: Boolean query • Type terms and operators (and, or, ...) in a text box • Type terms, but select operators from a structure editor

12. Varieties of user interfaces End user interface. Allows a library user to search, browse, or retrieve known items. Librarian and system administrator interface. Provides services for an authenticated user to view, add, delete, or edit index records. Batch interface. Provides a method to index large numbers of digital objects automatically.

13. Data and metadata Structural data and metadata stored by the computer system enable the functions and the interface • The desktop metaphor has the concept of associating a file with an application. This requires a file type to be stored with each file: -- extension to filename (Windows and Unix) -- resource fork (Macintosh) • Effectiveness of searching depends on the type and quality of data that is indexed (free-text, controlled vocabulary, etc.)

14. Computer systems and networks The performance, reliability and predictability of computer systems and networks is crucial to usability • Response time instantaneous for mouse tracking and echo of key stroke 5 seconds for simple transactions • Example: Pipelined algorithm for the Mercury page turner

15. Conceptual Model:The Human in the Loop Return objects Return hits Browse repository Search index

16. Search Index Example: Design an interface for a simple fielded search. Interface: Fill in boxes, text string, ... ? Presentation of results ... ? Manipulation of results ... ? Functions: Specify field(s), content, operators, ... ? Retain results for manipulation ... ? Query options ... ? Data: Metadata formats ... ? Data structures and file structures ... ? Systems: Performance ... ?

17. Search Index(from a Discussion Class) It is frequently recommended that there should be separate user interfaces for different categories of users. (a) What features might be included? (b) What are the practical issues in implementing such a choice?

18. Return Hits: Snippets A snippet is a short record that a search system returns to describe and link to a hit. Example: Web search "brown topeka kansas" Legal Information Institute Brown v. Board of Education, 347 U.S. 483 (1954) (USSC+) 1. Syllabus , 2. Full Decision , 3. Syllabus & Opinions Only... www2.law.cornell.edu/cgi-bin/foliocgi.exe/...

19. Return Hits: Snippets Legal Information Institutewww2.law.cornell.edu/.../doc/%7B@1%7D/ hit_headings/words=4/hits_only - 2k - Oct 27, 2003 - Cached -Similar pages DOC BodyPage ... Case Information. Brown v. Board of Education of Topeka . No. 1. ... APPEAL FROM THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF KANSAS [*]. Syllabus. ...www2.law.cornell.edu/.../doc/%7Bt26262%7D/ pageitems=%7Bbody%7D/hit_headings/words=4 - 13k - Cached -Similar pages

20. Return Hits: Snippets

21. Return Hits: Snippets Choices in designing snippets: • Dynamic (generated from query+ document) or precomputed (from document only) • Content only or with related information (e.g., subject hierarchies) • Highlighting of search terms • Length v. number on page User must understand why the hit was returned

22. Return Hits: Ordering & Duplicates The order in which the hits are presented to the user: • Ranked by similarity of match (e.g., term weighting) • Sorted by a specified field (e.g., date) • Ranked by importance of document as calculated by some algorithm (e.g., Google PageRank) • Duplicates shown separately or merged into a single record • Filters and other user options

23. Browse If the documents are accessible online, user can browse content. • This can compensate for weaknesses in the underlying search system, e.g., the difficulty of indexing Web documents Otherwise, the user can browse substitutes, e.g., catalog records, subject hierarchies, etc. • This puts heavy demands on the precision of the underlying search system

24. Browse: Catalog Record

25. Browsing in Information Space Starting point x x x x x x x x x x x x x x Effectiveness depends on (a) Starting point (b) Effective feedback (c) Convenience

26. Convenience of Browsing Rapid access to materials Physical objects • Library or large private collection • Similar items stored close together (classification) Online information • Rapid delivery to desktop good system performance no administrative delays (authentication) Human skills and knowledge augment and extend the automatic methods of searching

27. Hierarchical browsing Level 0 Level 1 Level 2