This website includes a Java applet that displays the effect that various operations on an N-periodic, discrete-time signal (e.g. time shift, time scale, filtering) have on the signal and its spectra. Sketch the signal...

This site offers a variety of Java applets which explore the motion of planets, stars, and galaxies. Each applet comes with background information on the pertinent astrophysics, a technical description of what's being...

This site, created by John Walker of Formilab -- Switzerland, allows users to view the earth and moon, and daylight and night regions, from a wide range of viewpoints. These include from the sun, the moon, the earth, at...

This viewer lets users see near real-time images from the Landsat 5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+). When a Landsat satellite passes within range of the ground station at the USGS...

Authored by Frank G. Yanowitz, M.D, the Alan E. Lindsay ECG Learning Center is a helpful tool for students working toward careers in cardiovascular diagnostics and technology. It serves as an "introduction to clinical...