CS 430: Information Discovery
Lecture 14
Usability I
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Course Administration
• Assignment 2, late submission. All assignments
submitted by 2 p.m. today will be accepted. This is
a special concession because of my email problems
over the past week.
• Assignment 3. Due date is moved to Monday,
November 5 at 5:00 p.m.
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Information Discovery
Repository
User
Index
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The Human in the Loop
Return objects
Return
hits
Browse repository
Search index
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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
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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)
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Hierarchical browsing
Level 0
Level 1
Level 2
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8
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Searching
Changing users, changing user interfaces
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From
To
Trained user or librarian
Untrained user
Controlled vocabulary
Natural language
Fielded searching
Unfielded text
Manually created records
Full text
Boolean algorithms
Ranking methods
Stateful protocols
Stateless protocols
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")
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Principles of interface design
Interface design is partly an art; there are general principles:
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Consistency -- in appearance, controls, and function.
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Feedback -- what is the computer system is doing?
why does the user see certain results?
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Users should be able to interrupt or reverse actions
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Error handling should be simple and easy to comprehend
• Skilled users offered shortcuts;
beginners have simple, well-defined options
The user should feel in control
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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.
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Question 4: User Interfaces
(from Discussion Class 5)
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?
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Question 7: Success or Failure?
(from Discussion Class 5)
"Zero-hit outcomes occur on 30% of searches at some
services, ..."
(a) Why do you think that this happens?
(b) Is it necessarily bad?
(c) What can be done to reduce the bad aspects?
"Every time I search, I get 10,000 hits ..."
(d) Why do you think that this happens?
(e) Is it necessarily bad?
(f) What can be done to reduce the bad aspects?
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Disabilities
• What if the user:
is visually impaired or color blind?
does not speak English?
is a poor typist?
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Evaluation of Usability
• Observing users (user protocols)
• Focus groups
• Measurements
effectiveness in carrying out tasks
speed
• Expert review
• Competitive analysis
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Croft's Top Ten Criteria
1. Integrated Solutions
"A text retrieval system is a tool that can be used to solve part of
an organization's information management problems. It is not
often, however, the complete solution.
"Typically, a complete solution requires other text-based tools
such as routing and extraction, tools for handling multimedia and
scanned documents such as OCR, a database management
system for structured data, and workflow or other groupware
systems for managing documents and their use in the
organization."
Croft 1995
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Croft's Top Ten Criteria
2. Distributed Information Retrieval
There is a huge "demand for text retrieval systems that can work
in distributed, wide-area network environments."
"The more general problems are locating the best databases to
search in a distributed environment that may contain hundreds or
even thousands of databases, and merging the results that come
back from the distributed search."
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Croft's Top Ten Criteria
3. Efficient, Flexible Indexing and Retrieval
"One of the most frequently mentioned, and most highly rated,
issues is efficiency. Many different aspects of a system can have
an impact on efficiency, and metrics such as query response time
and indexing speed are major concerns of virtually every
company involved with text-based systems."
"The other aspect of indexing that is considered very important is
the capability of handling a wide variety of document formats.
This includes both standards such as SGML, HTML, Acrobat,
and WordPerfect [and] the myriad formats used in text-based
applications..."
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Croft's Top Ten Criteria
4. 'Magic'
"One of the major causes of failures in IR systems is vocabulary
mismatch. This means that the information need is often described
using different words than are found in relevant documents.
Techniques that address this problem by automatic expansion of
the query are often regarded as a form of 'magic' by users and are
viewed as highly desirable."
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Croft's Top Ten Criteria
5. Interfaces and Browsing
"Effective interfaces for text-based information systems are a high
priority for users of these systems. The interface is a major part of
how a system is evaluated, ... Interfaces must support a range of
functions including query formulation, presentation of retrieved
information, feedback, and browsing."
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Croft's Top Ten Criteria
6. Routing and Filtering
"Information routing, filtering and clipping are all synonyms used
to describe the process of identifying relevant documents in
streams of information such as news feeds ... large number of
archived profiles are compared to individual documents.
Documents that match are sent to the users associated with the
profile."
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Croft's Top Ten Criteria
7. Effective Retrieval
"Contrary to some researchers' opinions, companies that sell
and use IR systems are interested in effectiveness. It is not,
however, the primary focus of their concerns."
"... companies are particularly interested in techniques that
produce significant improvements (rather than a few percent
average precision) and that avoid occasional major mistakes."
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Croft's Top Ten Criteria
8. Multimedia Retrieval
"The perceived value of multimedia information systems is
very high and, consequently, industry has a considerable
interest in the development of these techniques."
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Croft's Top Ten Criteria
9. Information Extraction
"Information extraction techniques are designed to identify
database entities, attributes and relationships in full text."
Also known as data mining.
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Croft's Top Ten Criteria
10. Relevance Feedback
"Companies and government agencies that use IR systems also
view relevance feedback as a desirable feature, but there are
some practical difficulties that have delayed the general
adoption of this technique."
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