Multimedia Systems Design

Transcription

1 32027 Multimedia Systems Design Core Concepts of the WWW The WWW principle of universal readership is that once information is available, it should be accessible from any type of computer, in any country, and an (authorized) person should only have to use one simple program to access it. The World Wide Web was developed in 1989 by Tim Berners-Lee of the European Particle Physics Lab (CERN) in Switzerland NCSA Mosaic was originally designed and programmed for X by Marc Andreessen and Eric Bina at NCSA. Version1.0 was released in April, Version 2.0 was released in December 1993, along with version 1.0 releases for both the Apple Macintosh and Microsoft Windows Map of HCI 1

2 Tim Berners-Lee s slides to introduce the WWW (1993) Tim Berners-Lee The WWW uses hypertext as the method of presentation... links can lead from all or part of a document to all or part of another document. Documents need not be text: they can be graphics, movies and sound, so the term hypermedia (multimedia hypertext) applies equally well to the WWW. Tim Berners-Lee Map of HCI 2

3 Whilst hypertext is a powerful tool for finding information, it cannot cope with large amorphous masses of data. For these cases, computer-generated indexes allow the user to pick out interesting items from textual input. Tim Berners-Lee Whilst hypertext is a powerful tool for finding information, it cannot cope with large amorphous masses of data. For these cases, computer-generated indexes allow the user to pick out interesting items from textual input. There are therefore two operations a reader can use: the hypertext jump and the text search. Tim Berners-Lee Map of HCI 3

4 The web... was designed without any centralized facility... There is no central control. To publish data you run a server, and to read data you run a client. Tim Berners-Lee A feature of HTTP is that the client sends a list of the representations it understands along with its request, and the server can then ensure that it replies in a suitable way. Internet protocols Sets of rules that allow for inter-machine communication on the Internet. (Simple Mail Transport Protocol or SMTP) Telnet (Telnet Protocol) FTP (File Transfer Protocol) Usenet (Network News Transfer Protocol or NNTP) HTTP (HyperText Transfer Protocol) Map of HCI 4

5 Anatomy of a URL For example, the URL of the home page of the House Committee on Agriculture of the U.S.A. House of Representatives: 1.Protocol: http 2.Host computer name: www 3.Second-level domain name: house 4.Top-level domain name: gov 5.Directory name: agriculture 6.File name: schedule.htm Domain name examples.com commercial enterprise.edu educational institution.gov U.S. government entity.mil U.S. military entity.net network access provider.org usually non-profit organizations Languages CGI JAVA VRML XML Languages CGI programs for data that conforms to the CGI specification JAVA VRML XML Map of HCI 5

6 Languages CGI programs for data that conforms to the CGI specification JAVA "Write once, run anywhere. VRML XML Languages CGI programs for data that conforms to the CGI specification JAVA "Write once, run anywhere. VRML for the creation of three-dimensional worlds XML Languages CGI programs for data that conforms to the CGI specification JAVA "Write once, run anywhere. VRML for the creation of three-dimensional worlds XML to separate form from content A method for graphical input on the WWW Lesley Parks & Ernest Edmonds Map of HCI 6

7 The objects were constructed from a combination of graphics primitives (lines, circles, ellipses, boxes) with semantic information (constraints & textual descriptions). The data defining such an object was capable of being stored in and retrieved from a knowledge base accessible from a Web server. The results of the user's interaction with the object was to be returned to the server. Knowledge Server Browser Browser (face,x,y,z) Browser Knowledge Server Knowledge Server Map of HCI 7

8 Map of HCI 8

9 Good design Animation and fun Map of HCI 9

10 There is no reason why anyone would want to have a computer in their home Ken Olson, President of DEC, 1977 Superbad.com Map of HCI 10