http://design.alfred.edu/intromechanics.html

Alfred University offers this handy resource for engineering students taking an introductory mechanics course. The extensive list of properties and equations can be printed out and used as great quick-reference sheets. Topics covered include analysis of bodies in equilibrium, stress and strain, Hooke's Law, and deformation. In addition to the reference material, visitors to the site can apply the supplied formulae by trying the series of exercises. An example problem accompanied by a complete, step-by-step solution is given for each topic, and several other related problems are available for practice. A section on differential equations for two- and three-dimensional mechanics is also provided. [CL]

http://www.math.upenn.edu/%7Ewilf/DeturckWilf.pdf

Although it is presented as a collection of lecture notes on numerical analysis, this is essentially a full-fledged online book on the topic. Written by a professor of mathematics at Pennsylvania State University, the 125-page document spans three chapters and covers various forms of differential and difference equations, methods for solving them, and linear algebra. Scattered throughout the text are example problems that illustrate important concepts. Each section is concluded with a set of exercises that build on the presented material. Unfortunately, solutions for these problems are not provided. [CL]

http://www.pbs.org/newshour/extra/features/july-dec03/virus_11-24.html

Developed for high school students and teachers, this special online feature looks at the growing threat of computer worms and viruses. The first part, which can be useful for anyone interested in the topic, is an article addressing recent virus outbreaks and their effects on schools. Since students are often unaware of the inherent risks in email attachments and disk sharing, the article discusses the steps schools are taking to mitigate such risks. Accompanying the article is a lesson plan that compares computer viruses to their biological counterparts. This material comes from the Public Broadcasting System and was published on November 24, 2003. [CL]

http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fractions/egyptian.html

A former mathematics professor at the University of Surrey has created this webpage as an introduction to ancient Egyptian mathematics. Specifically, the site focuses on "how the Egyptians of 5000 years ago worked with fractions." While the methodology is somewhat peculiar, it is very clearly explained and anyone with an understanding of modern fractions should have no problem learning the Egyptian system. The author shows that Egyptian fractions actually have some advantages over their modern-day descendents. Several examples are shown and additional information can be found via links on the page. [CL]

http://ulcar.uml.edu/~iag/CS/Intro-to-ANN.html

The Crash Introduction to Artificial Neural Networks is not a comprehensive resource, but it provides a good overview of many aspects of the topic. Beginning with a discussion of biological processes in the brain, the site describes the function of neurons and how they are interconnected. Some historical events are mentioned, leading to the development of an artificial neural network. The famous perceptron configuration is the basis of subsequent discussions of training algorithms, prediction and classification functions, and data processing. [CL]

http://www.research.ibm.com/ponder/

Ponder This is a monthly problem that lets ambitious people "match wits with some of the best minds in IBM Research." The problem is usually fairly abstract and requires refined mathematical skills, critical thinking, and patience to solve. Each month a new problem and the solution for the previous month are posted online. Users are encouraged to submit their answers for possible recognition on the website. Visitors to the Ponder This website can browse previous problems and solutions dating back to May 1998. [CL]

http://www.free2code.net/tutorials/

This website contains a wide variety of computer related tutorials ranging from specific programming languages and operating systems to computer networking and Web development. Submitted by members of the Free2Code community, the tutorials vary in style and can be general introductions to a broad topic or they can focus on a particular aspect of an application. Some popular tutorials that fall into the former category include Number Systems, PHP and MySQL, and an Introduction to Flash MX Design. A code archive is also available to help programmers with common problems. [CL]

http://www.karlscalculus.org/calculus.html

Few calculus resources, either online or offline, can match the sheer depth and user-friendliness of Karl's Calculus Tutor. The site contains educational material that is covered in a standard introductory calculus course. Entire chapters about limits, integrals, and derivatives are presented. Nearly every topic is accompanied by a detailed example, and a recently added midterm practice exam allows students to test their knowledge. The author is continually adding new material, stating that users should "expect a new unit to come on line every month or so." Two online calculators are also provided. [CL]