Henry Lieberman
MIT Media Lab
Version 1.0, March 1996
This is a guide for demonstrating Letizia, a user interface agent for helping browse the World Wide Web.
If you're new to Letizia...
This documents assumes that you already know the basic idea of Letizia. If you don't, start with the following reference:
Henry Lieberman, Letizia: An Agent for Assisting Web Browsing, International Joint Conference on Artificial Intelligence, Montréal, Canada, August 1995.
This document, along with other information about Letizia, can be found on the Web at:
http://www.media.mit.edu/~lieber/Lieberary/Letizia/Letizia-Intro.html
The easy way to demo Letizia is just to play the Quicktime movie of Letizia that you will find on that page. It's URL is
http://www.media.mit.edu/~lieber/Lieberary/Letizia/Letizia.mov
This is a 5 MB file and lasts about 2 minutes.
Installing Letizia on a Macintosh
Letizia requires:
[optional, improves performance]
Letizia comes as as an application written in Macintosh Common Lisp. It should be placed in a folder called Lisp Folder on the disk. It takes approximately 2.5 MB.
I have installed Letizia on the machine Brazil in 309. Icons for the Letizia application and the Letizia movie appear on the desktop.
Starting Letizia
Double click on the Letizia application. When Letizia starts up, it will automatically launch Netscape [it may ask you where to find Netscape on your machine]. It will take a minute or two for Letizia to initialize Netscape. Letizia will configure three Netscape windows, as shown below.
The left-hand window is [normally] for the user to browse manually. The two windows on the right are under the control of the agent. The window at the top right displays search candidates, those pages that Letizia considers likely candidates for recommendation to the user; the bottom right window displays those recommendations that pass the relevance tests. Both windows are updated continuously as the user browses. If a given page appears in both right-hand windows, that indicates a recommendation that was particularly successful.
Initially, all windows will come up with my home page, illustrated below.
Return to the Letizia application, and start up the Letizia agent from the Letizia menu.
The Lisp listener window displays a trace of Letizia's exploration of Web pages. Each time the user or Letizia reads in a page, a line is printed out this window.
Letizia is now running. Stopping Letizia is done by choosing Abort from the
Eval menu, or typing
and period at the same time.
Web browsing with Letizia
We now present a recommended browsing sequence for showing off Letizia's capabilities.
We start with Henry Lieberman's home page, a typical personal home page on the Web. It contains such items as a biography and publications list.
Choose the link to the home page for Programming by Example, an example of a typical topic-oriented home page on the Web.
The Programming by Example home page is structured as a "FAQ", or frequently-asked question list. It contains introductory material to the topic, lists of resources, etc. Explore the links off this page for a while.
As you explore each page, Letizia reads the page, and constructs a user profile consisting of the frequency of keywords indicative of the content of the page. This profile is used to filter recommendations dynamically.
By exploring the pages for Programming by Example, the user is "training" the system to be interested in the topic "programming by example", as well as related topics that tend to appear in the pages, such as "software agents", "artificial intelligence", etc.
Now, return to Henry's home page [using the Go menu], and choose the "publications" link.
As you are looking at this page, Letizia will explore the links from it. The papers should start appearing in the top right window, periodically. As Letizia determines which papers are relevant, mostly the ones whose subject material overlaps the "programming by example" topics learned on browsing that subject page, Letizia will display those pages in the bottom right window. Papers that appear simulataneously in both right-hand windows are particularly recommended by Letizia. It should wind up choosing about a third of the papers.
Caveats and tips for better demos
Letizia's HTML parser is not yet complete. It may choke if you visit pages with complex HTML. If you stick to the pages off my home page, it should work.
Work slowly! Letizia sometimes takes a while to catch up to the user. If you hop from page to page too quickly, Letizia might not notice that you hit that page.
Netscape sometimes get confused about which window is which. You may start seeing pages appear in a different window than you expect, especially if you accidentally select one of the agent windows. Workaround: Wait until Letizia is not reading a page, select first the bottom right window, then the top right window, then the left window. This will re-establish the window ordering. To be fixed.