The GCP Real-Time data display may require two minutes or more to get data and make startup computations. Please take the opportunity to read the information on this utility. At modem speeds, there probably will be too much data for the intended real-time update at one trial per second. The java program may have difficulty at startup, but if it crashes, you can try again. We hope it works for you because it is an interesting and informative display. For a description of the project, see the GCP homepage.

1. What is this?

The Java Basket Observer is an applet that allows for a near-realtime (10-minute delay) inspection of the behavior of a network random event generators (REG's) located at several places of the world. Data from these REG's, also called EGGs, are collected at a central computer, the Basket. The Java applet contacts the basket at regular intervals, gets the data, and displays it in various formats.

The project itself is explained elsewhere. The rest of this page explains the use of the observer applet.

2. What do I need to see it?

Basically, you need a Java-enabled browser. There is an audio component, but sound is not essential for viewing the display. The applet is in beta, so your browser might not like it. If you have difficulty, please let us know the details at

3. What can it do?

Three kinds of displays are currently available:
  1. The Z-squared value for each EGG at a specific time is shown as a rectangle with size proportional to the deviation; bright colors indicate large momentary deviations;

  2. The cumulative history of each EGG's behavior is plotted as a random walk with steps computed as Z-squared - expectation (Z²-df). This display is available with a one-second and with a one-minute resolution; again, brighter colors signify larger deviations;

  3. The coherence of all EGGs at a specific time (calculated as the sum of squared deviations (Z-scores) of the mean behaviour of all REG's).

Note that the cumulative displays will rescale if they reach the border of the display area. The background color will change slightly after a rescaling has been performed.

The Basket Observer also plays musical notes with pitch and loudness related to the momentary data values, against a steady "heartbeat" background.

At startup the first display is shown. Other displays are chosen via the bottom button panel. If you want to inspect individual EGGs you can switch displays with the button directly at the bottom of the EGG.

4. What it can't do.

This utility will not work properly if the user's clock is off by more than 5 minutes. Also there is a known bug causing a null-point exception error to occur after about an hour. Occasionally, such an error will occur immediately, probably because the amount of data to process has become very large. If you are a java programmer and want to contribute to the project please contact us: or GCP. If you want to examine the source code for this application, it can be downloaded from the realtime java archive. For convenience, there is a gnuzip tarfile containing all the individual files.

Return to Display.

The project is fully described in a dedicated website at

last update: April 12, 1999.