The problem with trees Many systems are organized hierarchically. The CERNDOC documentation system is an example, as is the Unix file system, and the VMS/HELP system. A tree has the practical advantage of giving every node a unique name. However, it does not allow the system to model the real world. For example, in a hierarchical HELP system such as VMS/HELP, one often gets to a lead on a tree such as: HELP COMPILER SOURCE_FORMAT PRAGMAS DEFAULTS only to find a reference to another leaf: Please see HELP COMPILER COMMAND OPTIONS DEFAULTS PRAGMAS and it is necessary to leave the system and re-enter it. What was needed was a link from one node to another, because in this case the information was not naturally organized into a tree. Tim Berners-Lee, Seeing With Fresh Eyes A City Is Not a Tree hierarchywww
Cool URIs don't change An Essay by Tim Berners-Lee www.w3.org What makes a cool URI? A cool URI is one which does not change. What sorts of URI change? URIs don't change: people change them. The User Interface of URLs www
The illustrated guide to a Ph.D. An Article by Matt Might matt.might.net Show image 0 Show image 1 Imagine a circle that contains all of human knowledge. By the time you finish elementary school, you know a little. By the time you finish high school, you know a bit more. With a bachelor's degree, you gain a specialty. A master's degree deepens that specialty: Reading research papers takes you to the edge of human knowledge. Once you're at the boundary, you focus. You push at the boundary for a few years. Until one day, the boundary gives way. And, that dent you've made is called a Ph.D.. Of course, the world looks different to you now. So, don't forget the bigger picture. Keep pushing. knowledgescienceprogressresearch