Computer Networks and ISDN Systems 26 (Suppl. 2 double issue) (1994) S71-S74

Touring And Navigating a Global Learning Environment

- the Web

Jon Crowcroft and Gordon Joly* Department c?f Computer Science, UCL, Cower St. London, WClE 6BT, UK

Abstract

The World Wide Web is one of the fastest growing Networked Information Systems in history. The revolution has been

brought about by use of GUIs such as NCSA’s Mosaic, and the distributed hypertext language HTML, Universal Re-

source Locators, and with simple protocols for client server access. Another contributory factor has been the develop- ment of a number of filters that have permitted the introduction of material prepared using almost all the well known word processing and desk-top publishing tools. However, this growth has led to problems for new users

finding the information they want. This paper is about a tool for generating tours of the web to enable experts to become cyber-carto-graphers, mapmakers of the new virtual world, and share their findings with novice users.

Keywords: World Wide Web, Information Services, Distributed Systems

1. Introduction

The World Wide Web (WWW) project [l] has

revolutionised the Internet. Until recently, all

access to information resources had been through

command line interfaces familiar to computer users of the 60s and 7Os, but alien to the new

breed of users. These have been brought up on

point-and-click systems on MACs and PCs, that had broadened the appeal of computers as eve- ryday tools. Figure 1 illustrates this Information

world.

This paper is about a tool for generating tours

of the web to enable experts to become cyber- carto-graphers, mapmakers of the new virtual world, and share their findings with novice users.

*Corresponding authors: Email: j.crowcroft@cs.ucl.ac.uk, g.joly@cs.ucl.ac.uk

Factors in the massive success of the design and implementation of WWW include:

Graphical User Interfaces to navigate and ac-

cess the information. Mosaic [2] is the most commonly used GUI to access WWW. The model of access is that of client/server.

Distributed Hypertext Organisation - URLs (URNS etc)

“I am going to open the London University Acad- emy. I’ll teach everything by correspondence, solve all problems, answer all questions. I might start a mag- azine first, and then a newspaper, but first 1’11 have to build up slowly...My branch office will be the British Museum. If you like, I’ll give you a job later on”, (the brother in The Hard Life, Flann O’Brien, 1961)

The WWW is made out of many servers. Anyone can setup their own server and tell

0169-7552/94/$07.00 0 1994 - Elsevier Science B.V. All rights reserved

s72 Jon Crowcrofl and Gordon Joly / Touring And Navigating a Global Learning Environment - the Web

people where it runs. They can add l inks to • Common Ga teway Interface (CGI) other places. Thus a site can independent ly

provide for its users local informat ion, and The Common Ga teway interface a l lows the a view of the rest of the Web. W W W to subsume other informat ion servic-

es. This is the Info-bahn ana logy to the way • Fi l ters for ex is t ing documents prepared with that in the lower layer wor ld of the Internet ,

other tools, you can run IP da tagrams over j u s t a b o u t

a n y t h i n g .

It is poss ib le to conver t documents into

H T M L from the low level , backend langua- ges such as pos tscr ip t and RTF, s imple doc- The main p rob lem with the W e b ' s success is ument p repara t ion sys tems such as LaTeX its s ize , and the r e s u l t i n g d i f f i c u l t y fo r new and Troff, through to high level desktop pub- wanderers to f ind anything. l i sh ing sys tems such as F r amemake r

This paper is organised as fo l lows: In sect ion • Mul t i -purpose Internet Mai l Extensions: two, we discuss the design of Tang le ; in sect ion

M I M E [8] 3, we show how to author a tour guide; In sec- t ion 4, we show the structure of the sys tem for

The Web uses of a common interchange for- conduct ing a tour; in sect ion 5, we discuss re la t - mat that is extensible. Technology for MIME ed work . F i n a l l y , we d raw some c o n c l u s i o n s a l ready exists from its large user base in the about our sys tem and its usage. e lec t ronic mai l communi ty .

Users

Mosaic, Netf ind, Cello Browse r /Sea rch App l i ca t ions

URL, URN, DNS Hype r l i nk M a na ge me n t

C o m m o n Ga teway Interface (CGI)

Wais , Archie, Gopher , etc Search&Index Tools

E-Mail, Telnet, Ftp, HTTP Data Retr ieval Tools

TCP/ IP SLIP /PPP

Informat ion Stores and High Streets

Figure 1, The Whole Cornucopia of Cyberspace

.Ion Craweroft is a senior lecturer in the Department of Computer Science, University College London, where he is respon- sible for a number of European and US funded research projects in Multi-media Communications. He graduated in Physics from Trinity College, Cambridge University in 1979, and gained his MSc in Computing in 1981. and PhD in 1993. He is a member of the ACM, the British Computer Society and the lEE. Gordon Joly currently works in the MICE project at UCL CS. He graduated with a Ph.D. in the field of algebraic computing for general relativity and then worked in the field of expert systems. His interests in the WWW have stemmed from several years composing email to comp.ai.

Jon Crowcroft and Gordon Joly / Touring And Navigating a Global Learning Environment - the Web S 7 3

2. System Design Rationale contents of given WWW pages. It does not in- fringe copyrights or other restrictions. It may

Tangle is simple. It has 3 main components: suffer from timeliness problems, but these will reflect the true WWW performance characteristics

1.Ravelling - the process of conducting and in any case, and serve as an additional instruc- saving a tour of a part of the WWW. tion to the user on the cost of the information.

As the WWW community adds more and more 2.Un-tangling - the process of post-producing technology for caching, the disadvantages of the

a travelogue of the tour. latter approach fade.

3.Unravelling- the process of playing back, or The basic structure of the system then is as navigating a particular tour or tangle, follows. The client accesses a server where the

tangle lies as a script which is a CGI backend. The server runs the script, which traverses the

The goal is for experts who have a set of WWW pulling pages (possibly caching them)and domain-specific knowledge about areas of the sending them back to the client. At appropriate WWW to create tours for novices, or to introduce points (where the author has inserted playback other domain experts to the information base delays, as in a slideshow, or where there are available, choices in the tangle), a form is returned to the

client. The user fills this in, and it is submitted Work at Southampton University [9] on author- back to the same server, and unraveling the tan-

ing tools shows that the imposition of single tool gle continues (or halts if the user so requests). does not work. However, the most useful single mechanism for authors of information was helped 3. Ravelling a Tangle with the cutting and pasting of existing material into new structures. Selection of information To author or ravel a tangle document, a user from global library has just this property, needs simply to use a browser that keeps a his-

tory of where she has visited. Tangle then pro- When designing Tangle, we considered two vides a simple script to edit and convert this into

possible approaches, a Thread, which can be added to the author 's local WWW server's list of Threads.

1.A tour could simply be something that peo- ple treat as a document to browse, using A thread is a tree of URLs, held in a Unix Mosaic or some other tool, consisting of a file, that looks like this: single hypertext document at a single serv- er.

BNF for Thread:

2.A tour could be a living structure, existing as a set of pointers in a WWW server to the Thread : := Strand I Nexus

contents which reside at their original loca- tions. Strand : := <URL> [ ;URL] *

Nexus : := <ChoiceForm(URL, URL [,URL] *) >

The former approach has the advantage for the client/user of timeliness. Access to the document will be at local speeds. Reliability will be good.

However, the prime use for threads is to lin- The latter approach is far more in the spirit of earise documents, that have become too structured

WWW. It relies on no explicit copies of the sec- for smooth reading. tions of the tangle. It is robust to changes in the

$74 Jon Crowcroft and Gordon Joly / Touring And Navigating a Global Learning Environment - the Web

4. Unravelling a Tangle 7. Acknowledgements

Common Gateway Interface (CGI) A User Thanks to Tony Johnson for the Cornucopic visits a Tangle site simply by being given its view of the Superhighway. URL (offline, in E-mail, over the phone, in a newspaper, by telepathy). References

They access a site, and their WWW Client [1] T.J. Berners-Lee, R. Cailliau, J-F Groff, B. Pollerman. simply interacts with the WWW Server. The CERN World-Wide Web: The Information Universe

Electronic Networking." Research, Applications and Tangle server is a perl script which runs as a Policy, Vol. 2 No 1, pp. 52-58 Spring 1992, Meckler CGI backend to an Httpd. Publishing, Westport, CT, USA

The main problem with this approach is the 12] David D. Clark, David L. Tennenhouse. Architectural fact that a WWW client retrieves a page, and Considerations for a New Generation Protocols. Com-

puter Communication Review Vol. 20, No. 4, SIG- then stops. A WWW server has no way to say COMM '90, September 1990, pp. 200-208. "hold on, there's more/"

[3] B. Kahle, A Medlar. An information System for Cor- 5. Related Work porate Users: Wide Area Information Servers Connex-

ions - The lnteroperability Report, Report 5, Novem- ber 1991

There is a huge amount of work in Informa- tion Services at the time of writing. Apart from [4l F. Anklesaria, M. McCahill, P. Lindner. D. Johnson, D. the basic World Wide Web technology, one must John, D. Torrey, B. Alberti. The lnternet Gopher Pro-

tocol (a distributed document search and retrieval also mention systems directly aimed at searching, protocol), RFC 1436. 03/18/1993 rather than browsing models of user access. These include WAIS [3], Gopher [4], and Archie [6]. [5l Oliver McBryan. http://www.cs.colorado.edu/home/mc-

bryan/WWWW, html

On top of the basic WWW mechanism, sever- [6l Archie ftp://phoenix.ic.doc.ac.uk/computing./archiving/ al groups have built indexing and searching tools, archie

Two noteworthy ones are the WWWWorm [5] and the Jumpstation [7]. [7] Jonathon Fletcher, J.Fletcher@stirling.ac.uk http://

www. stir. ac. uk/jsbin/js

6. Conclusions [8] N. Borenstein, N. Freed. MIME (Multipurpose Inter- net Mail Extensions) Part One: Mechanisms for Spec-

Initial use of this tool has proved useful, if ifying and Describing the Format of lnternet Message Bodies, RFC 1521, 09/23/1993.

only as a means to introduce people to the func- tionality of the World Wide Web. The affect on [9] G.A. Hutchings, W. Hall, H.C. Davis. Hypermedia Link server load must now be measured, as with all Services: Accessing Networked Learning Resources, well behaved Robots and Spider. Advisory Group of Computer Graphics Multimedia

Workshop Report, AGOCG Report 24, December, 1993