Chapter 4

Education


CONTENTS

Biology

Figure 4.1 :

Biomorphs

by Lambda Systems Ltd.
Contact Info: info@lamsys.com
URL: http://www.lamsys.com/bm.html
Load Time: Fast
Source Code Included: No

Author's Description: An implementation of Richard Dawkin's Biomorphs, mentioned in the book The Blind Watchmaker.

Spend some time with this applet (about fifteen thoughtful clicks will do it) and you'll appreciate its seemingly simplistic premise-the gene in the center parents all the rest, and you can click something in the outside ring to make it the parent of the next generation. The more fantastic looking genes you select, the weirder its children will become.

Genome Browser Prototype

by Gregg Helt
Contact Info: gregg@fruitfly.berkeley.edu
URL: http://flybane.berkeley.edu/gregg/ProtoBrowser.html
Load Time: Fast
Source Code Included: No

Author's Description: A prototype of the genome map applet we are developing in order to present biologists with a flexible interface to genomic databases. Check back often-we are constantly updating!

This applet is a boon to biologists and other scientists studying DNA-you can move up and down the strand of fruit fly DNA, select a section to view the base pairs, and perform other detailed examinations. Also see JaMBW (this section), which is the entire collection that this applet is but one small part of, and Physical Mapping Calculators (this section).

JaMBW: Java-based Molecular Biologists Workbench

by Luca Toldo
Contact Info: TOLDO@EMBL-HEIDELBERG.DE
URL: http://www.embl-heidelberg.de/~toldo/JaMBW.html
Load Time: Medium Fast
Source Code Included: No

Author's Description: Molecular biology is now highly dependent on appropriate computer tools in order to design and interpret experiments. Of the many operations that a molecular biologist performs with the help of a computer, many of them do not need highly powerful computers and generally are meant to be a mostly "speed-up" to typical "back-of-the-envelope" operations.

This page houses links to the JaMBW collection of biology-related applets, a total of fourteen as of this writing, produced by an international team of scientists. They all relate to the study of and experimentation with DNA, including the Genome Browser Prototype (this section) but none of the links have the source code available.

PET Viewer

by Yuri Pryadkin
Contact Info: yuri@aludra.usc.edu
URL: http://www-hbp.usc.edu/HBP/groups/cortex/form.html
Load Time: Medium Fast
Source Code Included: No

Author's Description: Using this applet you can plot PET (positron emission topography) activity over an array of human brain slices.

This is another applet on the Gamelan directory dealing with similar subject matter-read as: brain slices-as the Whole Brain Atlas Navigator. For comparison, also check out the PickTest2 applet (Programming: User Interfaces)-read as: esophageal slices.

Physical Mapping Calculators

by Andre Grigoriev
Contact Info: andy@rag3.rz-berlin.mpg.de
URL: http://www.mpimg-berlin-dahlem.mpg.de/~andy/calc/mapcalc.html
Load Time: Fast
Source Code Included: No

Author's Description: These are calculators for predicting the experimental progress of various physical mapping projects.

There are two calculator applets accessible from this page for studying DNA results and/or genetics in general: Random Probe and Random Fingerprinting. Another useful collection of similar applets is JaMBW. Also check out the Genome Browser Prototype (both in this section).

predator-prey

by Adam Freeman
Contact Info: raptor@cse.ucsc.edu
URL: http://www.cse.ucsc.edu/~raptor
Load Time: Fast
Source Code Included: No

Author's Description: A realistic radiosity rendered shark swims after a school of .gif fish across the Web page. Looks cool! I used a hack to get rid of the image flickering.

Pause to admire the shark and fish chase, but don't think this is the predator-prey applet-at the bottom of the page, click the applet field in the left corner and begin a customizable simulation involving populations of rabbits and fox. The applet cycles through the number of generations you establish and draws the results on a corresponding graph.

Chemistry

Figure 4.2 :

Boltzmann Machine Tutorial

by Simon Dennis
Contact Info: mav@psy.uq.edu.au
URL: http://psy.uq.edu.au/~mav/java/Necker.html
Load Time: Fast
Source Code Included: Yes

Author's Description: A tutorial on the Boltzmann Machine neural network using the Necker cube as an example.

A simple, straightforward Java treatment of this subject. Source code and ample documentation are available. Other resources on the Gamelan directory related to neural networks include Hopfield Neural Network (Education: Computer Science), and The HTML Neural Networks (JavaScript:Other JavaScript Resources).

Chemical Education and Resource

by Jeff Milton, Brent Thomas, and David Yaron
Contact Info: milton@chem.cmu.edu
URL: http://www.chem.cmu.edu/milton.Spec
Load Time: Very Fast
Source Code Included: Yes

Author's Description: This is a chemical education site that is scheduled to be used in three chemistry classes (so far) at Carnegie Mellon University. Currently, applets include spectroscopic and statistical analysis simulators as well as data fitting resource applets for chemical data analysis (straight line, least squares fits). Source is available upon request (currently being documented).

This applet functions optimally on the page, not in a floating window, though you'll have to scroll around to see all the graphs in action. And it helps to have some knowledge of the subject matter-there's virtually no layperson's explanation of how to use this applet or what it does.

Molecular Dynamics Simulation

by Horst Vollhardt
Contact Info: horstv@pc.chemie.th-darmstadt.de
URL: http://www.pc.chemie.th-darmstadt.de/java
Load Time: Fast
Source Code Included: No

Author's Description: The applet performs a molecular dynamics simulation in real time with a hydrocarbon molecule. The molecule is rendered with double buffering and depth cueing. A VRML snapshot can be prepared and visualized with any VRML browser.

Watch a molecule in action and rotate, translate, or scale it with mouse and key combinations, or download a VRML snapshot for a true 3-D image.

PDB3D

by Scott Le Grand
Contact Info: legrand@tesla.mbi.ucla.edu
URL: http://www.mbi.ucla.edu/people/legrand/pdb.html
Load Time: Fast
Source Code Included: Yes

Author's Description: PDB3D is a high-speed 3-D molecule rendering applet which has been designed specifically for viewing protein data bank (PDB) format molecular structure files within Web pages. As a benchmark, PDB3D can render an alpha carbon trace of a 3,000 residue protein at approximately 2 fps and that of a 500 residue protein at approximately 10 fps when running as interpreted Java within Netscape 2.01.

Shrink and turn the cytochrome at the top of this page using the right and left mouse buttons respectively. The author refers users to the Web page's source for the source to this applet, and provides detailed installation instructions along with a list of links to view PDB3D in action.

Figure 4.3 :

The Second Law

by Christopher Grayce
Contact Info: cgrayce@uci.edu
URL: http://www.chem.uci.edi/instruction/applets/bounce.html
Load Time: Fast
Source Code Included: No

Author's Description: The second law of thermodynamics is demonstrated by a bouncing box-gravitational potential energy turns into heat.

You have to see this cool visual intepretation of chemistry to properly appreciate it-note the rippling action of each line within the box as it relates to color/temperature changes and reaction to gravity.

Sketch & Fetch

by The Paradigm Exchange
Contact Info: lsmith@sunset.net
URL: http://www.tripos.com/SandF.html
Load Time: Fast
Source Code Included: No

Author's Description: An application for searches in chemical databases. A sketch applet that lets you sketch the substructure of a molecule and a search for this substructure is performed in one of three chemical databases. The molecules found are also displayed using an applet.

Click and place atoms of several compounds (choose individual substances with the pull-down menu) and click Search to find a match. The applet will search the available databases for compounds that resemble the user's drawing and display them on a subsequent page. The found molecules can be rotated, translated, and scaled, viewed in three different ways, or translated to VRML. If you're looking for freehand drawing applets, see WebDraw Applet (Network and Communications: Chat and Multiuser) and/or NINA (Multimedia: Graphics Resources).

Computer Science

Binary Tree Viewer

by Michael Woodson
Contact Info: n9942097@fozzie.cc.wwu.edu
URL: http://rowlf.cc.wwu.edu/~n9942097/bt.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: This applet helps show how a binary tree works.

This page features descriptions of the tools on the toolbar, the applet source code, an information page containing some documentation, and a link to another similar applet.

Comparison of Routing Techniques

by Baogang Yao and Shingang Chen
Contact Info: b-yao@cs.uiuc.edu, s-chen5@cs.uiuc.edu
URL: http://www.ncsa.uiuc.edu/People/byao/cd423/mp1/mp1.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: Comparison of routing techniques.

Despite the author's warning, all three of these applets performed well, both individually and on the group page, on both our Windows 95 and Macintosh testing platforms.

Computer Graphics Tutorial

by Brandon Bachman, Scott Foster, John Hoopes, Eric Mercer, and Kathy Vamianakis
Contact Info: bbachman@facility.cs.utah.edu
URL: http://www.cs.utah.edu/~bbachman/gtutor
Load Time: Fast
Source Code Included: No

Author's Description: An interactive tutorial written in Java that teaches the fundamentals of computer graphics. Topics include perspective viewing, scan fill, line drawing, bezier curves, bezier surfaces, and so forth.

Two- and three-dimensional lessons are available on this applet page, as outlined in the main menu frame. Overviews appear in the left frame while the interactive applet demo runs on the right. You will have to scroll up and down to view the images and use the button controls, but wait till the text is complete, otherwise the time lapse just increases.

Convex Hull Graph Algorithm Demo

by Jeff So
Contact Info: soj3990@cs.uleth.ca
URL: http://www.uleth.ca/~soc101
Load Time: Medium Fast
Source Code Included: Yes

Author's Description: An applet that demonstrates the speed and technique between Quick Hull algorithm and Brute Force algorithm in solving the Convex Hull problem.

Click to plot points on the applet field, choose an algorithm, and click Go. Source code is included.

Figure 4.4 :

Digital Simulator

by Iwan van Rienen
Contact Info: ivr@bart.nl
URL: http://www.lookup.com/Homepages/96457/digsim/load.html

Loading Time: Fast

Source Code Included: Yes

Author's Description: A Digital Simulator in Java-learn how digital components work by loading an example schematic or draw your own schematic. Over 30 components available: switches, LEDs, ports, flipflops, and so forth. When running offline you can also save your own schematics. Includes over 400K of documented source code.

Some knowledge of the components is necessary to really play around successfully, but the concept is way cool. Original schematics are savable and loadable when run offline using appletviewer, and they're apparently much faster than the perfectly fast online simulations. Also see Active Schematics (Education: Engineering).

Figure 4.5 :

Dijkstra's Shortest Path Algorithm

by Carla Laffra
Contact Info: carla@cs.pace.edu
URL: http://www.cs.pace.edu/~carla/graph.html
Load Time: Fast
Source Code Included: Yes

Author's Description: Draw your own graph with edges and set their weights. Or, simply modify an example graph. Then, step through an animation of Dijkstra's algorithm to determine to shortest path between points in a graph. During the animation, the applet explains each step.

If your knowledge of this subject is limited, scroll through the documentation and run the example first. The pull-down menu in the upper-left corner allows you to customize various aspects of the demo, while the buttons on the right side execute the primary functions. The source code link is provided on the first page.

Eight Puzzle Solver Applet

by Christopher Waterson
Contact Info: waterson@eecs.umich.edu
URL: http://ai.eecs.umich.edu/people/waterson/EightPuzzle
Load Time: Fast
Source Code Included: No

Author's Description: This applet animates the A* search method for solving the Eight Puzzle, dynamically displaying the search tree as it is built. (Note that it has some problems when running on platforms that are not preemptive.)

This applet resembles The javaTiles (Art and Entertainment:Puzzles) but it shows solutions graphically as search trees and provides a way for the user to watch the puzzle solve itself. Also check out Java Slider (Art and Entertainment: Puzzles) for comparison.

Example of a Queue

by Dan Cieslak
Contact Info: dcieslak@darwin.cc.nd.edu
URL: http://www.nd.edu/~dcieslak/queue/DJC_QueueTest.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: A simple example of the Queue Data Structure.

Yes, it is a simple example of the queue data structure. And the source code for the Test, the Queue Class, and the Node Class is included.

Ferry Applet

by Igor Dvoeglazov
Contact Info: igor@idir.net
URL: http://www.idir.net/~igor/ferryapt.html
Load Time: Fast
Source Code Included: Yes

Author's Description: A variant of Cannibals/Missioners game. Solving part is included. AWT components. Graphics. Animation.

Choose one of four versions of this applet-with or without frames, 256 or more colors to view this logic puzzle, and one of 25 solutions for the applet to animate. Netscape users will not be able to save games and they may have difficulty getting the people to load up on the left side of the river.

Handwriting Slant Demo

by Lambert Schomaker
Contact Info: schomaker@nici.kun.nl
URL: http://www.nici.kun.nl/unipen/hwr-tutor/slant.html
Load Time: Fast
Source Code Included: Yes

Author's Description: An educational program to show the effects of slant correction by the shear transformation. Intended for people interested in the problems of handwriting recognition.

Simply stated, this applet unslants bad handwriting, making it easier to read. Documentation and source code are included.

HexCalc

by Nigel Gamble
Contact Info: nigel@nrg.org
URL: http://www.nrg.org/hexcalc/HexCalc.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: A simple, 64-bit, programmer's hexadecimal calculator.

That's what it is: simple and scientifically useful. Source code is included.

Hopfield Neural Network

by Matt Hill
Contact Info: mlh1@cornell.edu
URL: http://crux3.cit.cornell.edu/~mlh1
Load Time: Fast
Source Code Included: Yes

Author's Description: A Hopfield neural network memory that allows you to enter and test patterns.

Commit these applet controls to memory before playing the demo or you'll be constantly scrolling up and down; this doesn't affect the applet's functionality, but it's a pain. Also, the only way to know if the applet's ready to roll is to start clicking, so don't wait for a Begin message or you'll never get started. Other resources on the Gamelan directory related to neural networks include Boltzmann Machine Tutorial (Education: Chemistry) and The HTML Neural Networks (JavaScript: Other JavaScript Resources). Also have a look at Biomorphs (Education: Biology), and, for fun, the Life games in the Art and Entertainment: Life Games section.

Interactive Binary Search Tree Demos

by Doug Ierardi
Contact Info: ierardi@cs.usc.edu
URL: http://langevin.usc.edu/BST
Load Time: Very Fast
Source Code Included: No

Author's Description: Interactive demos of several binary search tree data structures (standard, red-black trees, treaps, and splay trees).

Even if you don't have a grasp of the principles behind these applets, the graphics and animation are impressive: the elastic way the nodes bounce and cast shadows, and the textures and colors of the nodes themselves, are all pretty cool. Another great example of interactive, entertaining, educational Java.

Intersecting Lines (Scanline Algorithm)

by Kenneth Baltz
Contact Info: baltz@usc.edu
URL: http://www-scf.usc.edu/~baltz/intersect/example1.html
Load Time: Fast
Source Code Included: Yes

Author's Description: This is the result of a class assignment to implement a scanline algorithm to detect intersections of somewhat arbitrary lines. It's my first Java applet, so be nice. :-)

This applet counts the number of intersections in a random assortment of horizontal lines by passing a vertical line through. Click the mouse button to move step by step through the algorithm, see the intersections listed, and wait for the final number.

Figure 4.6 :

Jess

by Ernest J. Friedman-Hill
Contact Info: ejfried@ca.sandia.gov
URL: http://herzberg.ca.sandia.gov/jess
Load Time: Fast
Source Code Included: Yes

Author's Description: Jess is a clone of the popular expert system shell CLIPS written as a Java applet. Jess uses the first Rete algorithm for pattern matching and is downward-source compatible with CLIPS (a valid Jess script is a valid CLIPS script).

Plenty of helpful stuff to go with the free source, including a downloadable user's manual, links to CLIPS pages and sites, and a cool demo on Monkey and Bananas (or Monkey and Grapes if you so prefer). Top marks for usefulness, simplicity of use, and generosity with information.

MergeSort Demo With Comparison Bounds

by David Neto
Contact Info: neto@eecg.utoronto.ca
URL: http://www.eecg.utoronto.ca/~neto/teaching/238/16/mergesort.html
Load Time: Fast
Source Code Included: Yes

Author's Description: This page demonstrates MergeSort. It focuses on counting the number of comparisons made. A recurrence relation for worst-case comparison count is derived, and the applet shows both the actual and predicted maximum number of comparisons made for each recursive call for the n=16 case.

A very nicely executed page and applet, with all the explanations and instructions a user could want. On the Windows 95 testing platform, though, the graphics got more and more distorted with each new sort though it didn't crash-unlike Netscape on the Macintosh testing platform.

MultiLayer Perceptron Neural Network

by Gerard Davison
Contact Info: GMDavison@iee.org
URL: http://www.rdg.ac.uk/~shudavsn/MLPPage/home.htm
Load Time: Fast
Source Code Included: Yes

Author's Description: This is my second year Cybernetics project to write a neural network. I have written an MLP that can be configured in a variety of ways. Further versions will include some different learning algorithms such as momentum and SAM (born at the University of Reading).

Netscape 3b4 users beware-this applet will crash your browser if you click Get Training Info File. All others, follow the simple instructions to learn about basic cybernetics. The source code and a documentation page are available for the taking. Other resources on the Gamelan directory related to neural networks include Boltzmann Machine Tutorial (Education: Chemistry), Hopfield Neural Network (Education: Computer Science), and The HTML Neural Networks (JavaScript: Other JavaScript Resources).

Figure 4.7 :

Recursion and Backtracking

by Dr. Narayan Murthy
Contact Info: murthy@pacevm.dac.pace.edu
URL: http://www.cspace.edu/~www/EDXLG8V5/queens.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: Recursion and Backtracking.

Watch this applet try to solve the Eight Queens problem-the challenge is to arrange eight queens on a chessboard so that none puts the other in check. Don't try to speed up the game or otherwise adjust the controls while a solution is being plotted, though, or the demo will freeze up. For real chess, check out the following Art and Entertainment: Board Games entries: GrandMaster Java Chess Viewer, iChess, and WebChess.

Round Robin Scheduling

by Fabio Kon and Mario Medina
Contact Info: f-kon@cs.uiuc.edu, c-medina@cs.uiuc.edu
URL: http://www-courses.cs.uiuc.edu/~c-medina/mp1
Load Time:
Source Code Included: Yes

Author's Description: This site describes and provides a simulation of Round Robin Scheduling, one of the oldest, simplest, fairest, and most widely used scheduling algorithms, designed especially for time-sharing systems.

Unfortunately, Windows 95 users have to scroll up and down while this demo is running to see all the elements in action. This can mess up the graphics on the lower half of the applet field. Plenty of instructions and other documentation are available along with the source code.

Spectrum Analysis: Amplitude & Frequency Modulation

by Hewlett-Packard Test and Measurement
Contact Info: Use feedback form on Web site
URL: http://www.tmo.hp.com/tmo/appnotes/interactive/hp-am-fm.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: This is an electronic version of a longtime favorite Hewlett-Packard application note AN 150-1 Spectrum Analysis: Amplitude & Frequency Modulation. There are two interactive Java signal models allowing the exploration and experience of basic concepts underlying AM and FM modulation, as well as a completely republished version of the original paper document implemented in Adobe Acrobat format bundled with QuickTime animations.

Everything you ever wanted to know about this subject and more. UNIX users applaud-there's even a download file for you, alongside the Macintosh- and Windows-specific files.

Figure 4.8 :

Technical Dictionary

by Scott Dexter
Contact Info: sdexter@shl.com
URL: http://www.shl.com/java/SHL.html
Load Time: Fast
Source Code Included: Yes

Author's Description: Over 6,000 terms in one place!

Contains programming-related terms, companies, acronyms, simple commands, and more. The definitions have been reprinted (with permission) from the Computer Desktop Encyclopedia.

TourOpt

by Tim Stockheim
Contact Info: stockheim@wiwi.uni-frankfurt.de
URL: http://www.wiwi.uni-frankfurt.de/~stockhei/touropt.html
Load Time: Medium Fast
Source Code Included: Yes

Author's Description: Several heuristics for solving the Traveling Salesman Problem. You may solve random examples or even define your own problems graphically! This is a part of our LogIN (Logistics Integrator Network) project...the next step is our COoperative Simulating Annealing (COSA) Workbench.

This applet takes a long time to load, so exercise some patience. Check out the LogIN project page (http://www.wiwi.uni-frankfurt.de/IWI/LogIN) for information on the whole project, and the Traveling Salesman Applet (this section) for comparison.

Traveling Salesman Applet

by Martin Hagerup
Contact Info: hagerup@dk-online.dk
URL: http://www.dk-online.dk/users/hagerup/java/tstdk.htm
Load Time: Very Fast
Source Code Included: Yes

Author's Description: Find the shortest route through N cities. Educational 350-line applet wtih multiple choices, buttons, and checkboxes. Includes small road constructor animation on a hot summer day. Also known as the Travelling Salesman Problem.

Also see TourOpt (this section ) for comparison with a similar resource.

Virtual Memory Simulation With Multiple Processes

by Joyjeet Bhowmik and Avijit Chakraborty
Contact Info: bhowmik@scf.usc.edu, chakrab@scf.usc.edu
URL: http://www-scf.usc.edu/~bhowmik/final/test.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: A simplified virtual memory simulation in a uniprocessor environment running multiple processes and doing context switching based on page faults only.

Link to the Descriptions page for documentation and such before running this demo-if you stop to jump between pages, reset the demo and start again rather than clicking Continue.

WebRoute: Java Based Shortest Path Routing

by Andrew Fetterer, Brajesh Goyal, and Nisha Agarwal
Contact Info: fetterer@cs.umn.edu or brajesh@cs.umn.edu
URL: http://www.cs.umn.edu/~fetterer/routing/route.html
Load Time: Fast
Source Code Included: No

Author's Description: The High Performance Geographic Information Systems Lab at the University of Minnesota is pleased to announce WebRoute. WebRoute is a Java applet that computes the shortest path from a source to a destination. We currently use a map of Minneapolis, Minnesota for the routing. The applet acts as a client to a Java-based routing server at the University of Minnesota.

Choose any two intersections on this map by double-clicking the source first and then the destination, and the University of Minnesota's server will return the shortest possible route to the message panel at the right side of the page. Other city planning/layout resources on the Gamelan directory include Berlininfo (Miscellaneous: Other Miscellaneous Resources), Virtual Boston (Miscellaneous: Other Miscellaneous Resources), send2cgi.class (Miscellaneous: Other Miscellaneous Resources), and Map Searcher Demo Page (Special Effects: Imagemaps).

Engineering

Active Schematics

by Jean-Claude Dufourd
Contact Info: dugourd@elec.enst.fr
URL: http://www-elec.enst.fr/java/skip-beta/test.html
Load Time: Very Fast
Source Code Included: No

Author's Description: Understand how electronic circuits work by clicking on inputs to change their values and see the wires and outputs change accordingly. Includes circuits built out of transistors or gates, static and dynamic.

Some documentation and the test.skip file are available, the latter on a linking page. Check out the Digital Simulator applet (Education: Computer Science) for another circuitry simulation demo.

Figure 4.9 :

A Bandwidth Demo

by Andrew Tuttle
Contact Info: tuttleal@newton.tuns.ca
URL: http://www.tuns.ca/~tuttleal/report/bandwidth/bandwidth.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: This is an interactive demo to help the layperson understand the concept of bandwidth. You can add several types of signals (a phone call, an MPEG video, and so forth) to an animated T1 line and find out how much you can squeeze into 1.5/Mbit/sec!

This extremely useful applet also comes accompanied by a clear, concise explanation of bandwidth and its associated issues/concerns. The demo shows animated images of phones, faxes, ISDN transmissions, and other information flying through a pipe-the available bandwidth on a T1 line. Can a T1 line handle six ISDN connections, ten phone calls, and two fax transmissions all at once? Figure it out using this applet.

CMOS Gate Demonstration

by Norman Hendrich
Contact Info: hendrich@informatik.uni-hamburg.de
URL: http://tech-www.informatik.
uni-hamburg.de/applets/cmos/cmosdemo.html
Load Time: Medium Fast
Source Code Included: No

Author's Description: A demonstration of CMOS technology basic and complex logic gates-inverter, NAND, NOR, and-or-invert, transmission gate, and D-latch. Nine applets embedded in HTML documentation, approximately 70K total. Now flickerfree and for the Beta-APL.

This page deserves a high rating because of how Java applets are used to describe and explain this subject matter. It did take ten minutes load up, though-on the second try-and worked sluggishly afterward at our testing speeds (28.8Kbps).

Diffusion, Drift, Recombination

by Chu Ryang Wie
Contact Info: wie@ascu.buffalo.edu
URL: http://www.acsu.buffalo.edu/~wie/applet/diffusion/diffusion.html
Load Time: Very Fast
Source Code Included: No

Author's Description: This applet visualizes the excess minority carrier processes in a semiconductor sample. It allows user inputs: conduction type, bias voltage, sample length, temperature, minority carrier mobility, and minority carrier lifetime. Users can also choose to see the number of carrier vs. time, concentration profile vs. time, and the peak position vs. time. It is intended mainly for undergraduate students in EE and Physics.

A very useful Javacised version of the Haynes-Shockly experiment. Other engineering resources worth checking out include Digital Simulator (Education: Computer Science) and Active Schematics (this section).

Emissions Calculator

by Michael Coon
Contact Info: canary@canaryair.com
URL: http://www.canaryair.com/combcalc.html
Load Time: Very Fast
Source Code Included: No

Author's Description: The Emissions Calculator calculates the exhaust components of a combustion process in a variety of units.

It's the Java Emissions test-this calculator will tell users how much of which compounds are emitted by burned fuel. Input the fuel composition percentages on the applet page, click Calculate, and view the results measured in your unit of choice in a separate window.

Fermi Level vs. Carrier Concentration

by Chu Ryang Wie
Contact Info: wie@acsu.buffalo.edu
URL: http://www.acsu.buffalo.edu/~wie/applet/fermi/fermi.html
Load Time: Fast
Source Code Included: No

Author's Description: This is an applet that teaches the relationship between Fermi level and carrier concentrations in a semiconductor. It also shows how the doping of donor and acceptor impurities affect the carrier concentrations and Fermi level. Intended mainly for ECE and Physics majors.

Click and drag the magenta line and all the graphs-Donor Impurity, Acceptor Impurity, and Fermi Level vs. Carrier Concentration-respond in kind. Choose from six test compounds and elements using the scroll-down menu.

Fuzzy Truck Simulation

by Chris Britton
Contact Info: brittch@eng.auburn.edu
URL: http://www.eng.auburn.edu/~brittch/truck/fuztruck.html
Load Time: Fast
Source Code Included: No

Author's Description: This applet simulates backing up a truck using fuzzy logic. Users can interactively change the location of the truck as well as its relative angle and fuzzy rules.

See also the PackerLayout applet (Programming: User Interfaces), which was used to create this demo, and the neural network applets Boltzmann Machine Tutorial (Education: Chemistry), Hopfield Neural Network (Education: Computer Science), and The HTML Neural Networks (JavaScript: Other JavaScript Resources).

Geodetic 2

by William Giel
Contact Info: rvdi@usa.nai.net
URL: http://ourworld.compuserve.com/homespages/WGiel/geod2.htm
Load Time: Fast
Source Code Included: Yes

Author's Description: Geodetic II is a complete rewrite of the original Geodetic applet, to solve for distance and direction between two points defined by latitude and longitude. This new version features pop-up maps from which you can pick your location(s) and a browsable online help file. Features threaded loading of resources to minimize stagnant time while applet sets up. Source, compiled classes, and images are available in a single ZIP file.

This applet produces a series of floating windows-the main control panel plus sinusoidally-projected world and U.S. maps-so it may take some time for things to get going.

Ideal Flow Machine

by William J. Devenport
Contact Info: devenport@aoe.vt.edu
URLs: http://www.aoe.vt.edu/flowdata/davenfac/course.html (WWW Courseware homepage)
http://www.aoe.vt.edu/flowdata/davenfac.html (Author's homepage)
Load Time: Fast
Source Code Included: No

Author Description: Designed as an educational Java Applet that brings ideal flow theory to life, this applet is also enjoyable to run if you have no technical background in fluid dynamics. The applet allows the user to design his or her own flow, and then see what it looks like by plotting streamlines. The result: a better understanding of fluid dynamics and some very pretty flow patterns. Examples and instructions are included in the accompanying Web pages.

Fortunately, this applet comes with good instructions, and a reassurance from the author that the user need not be an expert in fluid dynamics to find this demo really cool. If you don't design cars, boats, or planes for a living, you might want to read the instructions and study the examples first before running the demo. You can also fiddle around on your own, of course, but fair warning: It's not immediately obvious how to come up with something like the examples without a little preparation.

Java Beam

by Stephen Cooper
Contact Info: scooper@u.washington.edu
URL: http://ecsel.engr.washington.edu/JavaBeam
Load Time: Very Fast
Source Code Included: No

Author's Description: Java Beam is a direct manipulation environment in which analyzing a beam is as simple as applying loads and supports and watching what happens.

Lots of options to choose from on this educational page-learn about architecture, form and function by clicking different types of beams, different famous structures around the world, or by building something yourself. It's fun, it's interesting, it's cool.

Java Virtual Wind Tunnel

by David Ostiguy
Contact Info: ostiguyd@JSP.Umontreal.ca
URL: http://rafael.mit.edu/Java
Load Time: Very Fast
Source Code Included: No

Author's Description: The Java Virtual Wind Tunnel is a two-dimensional implementation of a computational fluid dynamics code. It's an example of how Java can be used for scientific and educational purposes, and it's cool to look at, too.

Check out this fascinating, colorful representation of how wind looks; even if fluid dynamics or physics in general isn't your strong suit, this moving graph applet and accompanying documentation is worth checking out just for the sheer beauty of it.

ParticleViewer

by Ronggen Pan
Contact Info: bobp@reynolds.umecheme.maine.edu
URL: http://reynolds.umecheme.maine.edu/~bobp/viewer/demo.html
Load Time: Fast
Source Code Included: Yes

Author's Description: A viewer to visualize particle motion from Stokesian Dynamics Simulation results.

There are three demos on this applet page-view them all for a well-rounded idea of the applet's potential. Also see the source contents in several HTML files, or download the ZIP.

Figure 4.10:

Unit Converter for Engineers

by Subrata Bhattacharjee
Contact Info: subrata@voyager5.sdsu.edu
URL: http://thermal.sdsu.edu/java_applets/unitconverter
Load Time: Very Fast
Source Code Included: No

Author's Description: This UnitConverter applet converts a wide variety of units from one system to another. Quantities include length, area, volume, mass, flow rate, density, force, pressure, energy, and many more.

Choose your quantity from the scroll-down menu in the center, select the units of conversion, and type in the exact figure(s). Invaluable for any student or professional in physics, chemistry, or engineering.

The Wavelet Generator

by Erica Palmer
Contact Info: pubert@frontiernet.net
URL: http://www.frontiernet.net/~pubert/java/Wavelet
Load Time: Very Fast
Source Code Included: No

Author's Description: This applet takes a low-pass filter (either entered by the user or chosen from a list) and iteratively calculates the scaling function and wavelet for that filter. Those functions are then displayed as graphs. Works with Windows 95 and NT, not necessarily under other OSes.

This applet worked as predicted by the author on the Windows 95 testing platform (that is, very well). It also worked as predicted by the author on the Macintosh testing platform (that is, not very well).

Figure 4.11:

Math

Abacus

by Luis Fernandes
Contact Info: elf@ee.ryerson.ca
URL: http://www.ee.ryerson.ca:8080/~elf/abacus.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: An abacus, and tutorial on using an abacus. Good educational value.

Aside from being a marvelous abacus tutorial, this page features several applets that enable the user to manipulate each of the abacus images. Netscape users may experience a bug in moving the beads, however sometimes they move, sometimes they don't. Source code and some documentation included.

Cheng-Pleijel Applet

by Ben Cheng
Contact Info: benny@earthlink.net
URL: http://home.earthlink.net/~benny/ChengPleijel.html
Load Time: Fast
Source Code Included: No

Author's Description: Explore the Cheng-Pleijel points of quadrangle with this applet!

Manipulate the positions of the five points by clicking-and-dragging them to new positions, to see how the point O responds. The applet response to the mouse is a bit slow on both our Windows 95 and Macintosh testing platforms, so the point may move further than you intend.

The Coffeecup Caustic

by Roy Williams
Contact Info: roy@cacr.caltech.edu
URL: http://www.cacr.caltech.edu/~roy/Caustic
Load Time: Very Fast
Source Code Included: Yes

Author's Description: A simple explanation and demonstration of the crescent-shaped light that appears when you drink coffee in the sunshine.

A lovely, straightforward explanation of geometry disguised as a cup of coffee.

Fouriersynthese

by Manfred Thole
Contact Info: thole@nst.ing.tu-bs.de
URL: http://www.nst.ing.tu-bs.de/schaukasten
Load Time: Very Fast
Source Code Included: Yes

Author's Description: This interactive applet illustrates fourier synthesis. German and English introductions are available.

Change the sine and cosine values and watch the corresponding oscillation effects.

Fractal Lab

by Henry J. Story
Contact Info: hjs@doc.ic.ac.uk
URL: http://www.wmin.ac.uk/~storyh/fractal/frac.html
Load Time: Medium Fast
Source Code Included: Yes

Author's Description: This applet allows you to experiment fully with fractals while being accessible to the novice. You can either choose from a set of standard fractals, or specify your own Contracting Affine Transformations. The color fractal appears gradually in a separate floating window. It is calculated in a separate thread allowing you to work on other things (such as thinking up the next fractal). Enjoy.

It takes a while for the initial grid to load and even more time for the floating window that displays the actual fractal. But the patterns are beautiful, and it is very easy for the beginner to experiment and see his or her results.

Geometry Applet

by David Joyce
Contact Info: djoyce@clarku.edu
URL: http://aleph0.clarku.edu/~djoyce/java/Geometry/Geometry.html
Load Time: Fast
Source Code Included: Yes

Author's Description: An applet and associated classes for illustrating Euclidean and similar geometric figures. Points may be dragged around to change the figure.

This math applet illustrates Euclid's Elements (http://aleph0.clarku.edu/~djoyce/java/elements/elements.html). Parameters, a description of the related classes and subclasses, and other instructions/information are also available at this URL, as is a gzipped tar file for the downloading.

HyperCuber Java Applet

by Greg Farrar
Contact Info: ferrar@uiuc.edu
URL: http://www.students.uiuc.edu/~ferrar/java/hypercuber/HyperCuber.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: This applet lets the user rotate a four-dimensional wireframe hypercube. It is a demonstration of the source code, which allows viewing and rotation of objects of arbitrary dimension.

Use the sliders to manipulate the cube in all four dimensions.

Java at Xanadu

by Jim Carlson
Contact Info: carlson@math.utah.edu
URL: http://xanadu.math.utah.edu/java
Load Time: Very Fast
Source Code Included: Yes

Author's Description: Java applets for teaching mathematics.

An assortment of Java applets to help teach calculus-experiment with graphs of functions and notions such as limits, tangents, derivatives, arc length, and area. Only one of the three applets demoed on this page comes with its source code.

Jmath Equation Renderer

by Robert Miner
Contact Info: rminer@geom.umn.edu
URL: http://www.geom.umn.edu/~rminer/jmath
Load Time: Fast
Source Code Included: Yes

Author's Description: The Jmath Equation Renderer applet allows users to include mathematical notation in Web pages by giving the Jmath applet HTML 3.0 math commands on a parameter line. The current version significantly extends the earlier version posted here, including symbol font support and many more HTML 3.0 tags.

This applet pages contains many demos/links to pages showing Jmath in action, plus the downloadable source with installation instructions, documentation, authoring tools, and more.

Figure 4.12:

Mandelbrot Escape Iterations

by Ivan Scott Fuller
Contact Info: ivan@voidstar.org
URL: http://www.voidstar.org/java/escape.html
Load Time: Fast
Source Code Included: No

Author's Description: While a Mandelbrot set is being generated, there are a lot of interesting and beautiful patterns that are never shown to you. Here's your chance to see them!

Click and drag the mouse over any part of the displayed Mandelbrot set, and watch the behavior of enhanced yellow pixels representing iterations in motion. Other Mandelbrot-related resources on the Gamelan directory include Java Man (Multimedia: Graphics Resources), Interactive Mandelbrot Set (Education: Other Educational Resources), and The Mandelbrot Set (Multimedia: Graphics Resources).

MathChase

by Marcia Burrows
Contact Info: marcia@bbsw.eyecon.com
URL: http://dev.eyecon.com/marcia
Load Time: Very Fast
Source Code Included: Yes

Author's Description: MathChase is an original game for one or two players at one computer. This challenging game features humorous, colorful animation and exciting competition. One player uses the keyboard and the other uses the mouse. In MathChase, thinking beats agility. If you can't find someone to play it with you, try letting your left hand compete with your right.

For those using Netscape for Windows: Do not scroll down the page while the applet is loading up. This can adversely affect game controls and/or functionality, and unfortunately the only way to find this warning in the first place is to do exactly the wrong thing-that is, to scroll down. If you've already made this mistake and the game performs poorly, the author advises you to reaccess the URL (reloading the page will not help) or quit and restart Netscape altogether. It is possible to safely access and read the instructions at the top of the page without wreaking havoc, so we hope you've read this review first!

Pierian Spring's Fractionator

by Pierian Spring Software
Contact Info: webmaster@pierian.com
URL: http://www.pierian.com/fractionator
Load Time: Medium Fast
Source Code Included: No

Author's Description: The Fractionator is a futuristic fraction manipulator that is part of Pierian Spring Software's Camp OS Math product. The Fractionator challenges the student to match a given fraction by sliding the numerator or denominator control. It adapts to the student's progress and gets progressively more difficult.

This is a great way to learn fractions, but it took about five minutes to load at 28.8Kbps. It is really worth the wait, though-the tutorial mixes whole numbers with fractions, runs numerator- and denominator-only quizzes, and displays the student's response graphically on a pie chart.

Pythagoras' Haven

by Jim Morey
Contact Info: morey@math.ubc.ubc.ca
URL: http://www.math.ubc.ca/~morey/java/pyth
Load Time: Very Fast
Source Code Included: Yes

Author's Description: An animated graphical proof of the famous theorem. A great example of an education applet that uses animation, text, and graphics to explain the proof. It also cleverly works around the absence of polygon fill operations.

Geometry in motion, plus some cool effects just for fun with the text instructions-if your monitor screen is anywhere close to normal size, you'll have to scroll down and click the text area to see these effects, but it's worth it.

Medicine

AIDSGraph

by Ken Shirriff
Contact Info: shirriff@eng.sun.com
URL: http://www.sunlabs.com/~shirriff/java/statsgraph.html
Load Time: Fast
Source Code Included: Yes

Author's Description: This applet provides a graphical interface to the CDC's database of AIDS cases in the United States. Difference categories of the database can be extracted and graphed in various ways. This applet illustrates the characteristics of the AIDS epidemic.

This graph provides realistic, timely information on the AIDS epidemic for medical and non-medical users alike. Unfortunately, the accompanying text is squeezed into a quarter-inch-wide frame at the top of the page that renders the documentation unreadable-if you use the slider, you can partially glimpse the link to the downloadable source, the CDC, and other would-be useful information.

Breathing Simulation

by Gerhard Ruckriegel
Contact Info: rucky@cip.e-technik.uni-erlangen.de
URL: http://cip2.e-technik.uni-erlangen.de/hyplan/rucky/Simulation/Simulation.html
Load Time: Medium Fast
Source Code Included: No

Author's Description: This applet simulates the interaction between an anaesthesical machine and a patient. Simple start the applet and you can see how pressure and other patient values vary. Both machine parameters such as frequency of breathing and patient condition as eg. right lung resistor can be changed.

The labels and controls are in German, but the basic idea still comes across. Start the anaesthetic "machine" and watch a realtime, real-to-life simulation. You will have to scroll vertically and horizontally to see everything in motion (it's a big graphic) but it's worth all the moving around to do it.

Figure 4.13:

Radiologic Anatomy Interactive Quiz

by Patrick Joiner
Contact Info: pjoiner@worldramp.net
URL: http://www.gsm.com/resources/raquiz
Load Time: Medium Fast
Source Code Included:

Author's Description: An interactive radiology quiz in Java. Test your knowledge of human anatomy by viewing X-ray films and identifying structures.

Other x-ray resources on the Gamelan directory include PET Viewer (Education: Biology), Whole Brain Navigator (this section), and PickTest2 (Programming: User Interfaces).

Whole Brain Atlas Navigator

by Keith A. Johnson, M.D. and J. Alex Becker
Contact Info: keith@bwh.harvard.edu, jabecker@mit.edu
URL: http://www.med.harvard.edu/AANLIB/cases/java/case.html
Load Time: Very Fast
Source Code Included: No

Author's Description: The Navigator is an interface to the image database of the Whole Brain Atlas.

This wealth of medical information on a variety of conditions and diseases is interesting but highly technical-the sliders and other controls manipulate time lapse, image sequence, and other variables, but this isn't the place to go for laypersons. For doctors and medical students, though, this is undoubtedly a useful and groundbreaking educational reference. Also see PickTest 2 (Programming: User Interfaces).

Physics

Balloon

by Sean Russell
Contact Info: ser@jersey.uoregon.edu
URL: http://jersey.uoregon.edu/vlab/Balloon
Load Time: Fast
Source Code Included: No

Author's Description: Another experiment in the Virtual Laboratory (http:/jersey.uoregon.edu/vlab), the Balloon shows the behavior of a gas in a balloon and allows the student to vary the temperature and observe the results.

Users create pressure and temperature changes by click-and-dragging the mercury and gauge needles, and the molecules inside the balloon respond. Adjust the measurements twice before clearing the graph to get a comparative reading.

Chernobyl Reactor

by Henrik Eriksson
Contact Info: her@ida.liu.se
URL: http://www.ida.liu.se/~her/npp/demo.html
Load Time: Fast
Source Code Included: Yes

Author's Description: Don't try this at home! This applet lets you control a nuclear power plant. Excellent use of animation, audio, images, and graphics. It is really nice that you can actually avoid a meltdown by correctly operating the various valves and pumps. Eventually it will allow the user to write an expert system to control the power plant.

Rewrite history by manipulating this applet's controls. Realtime valves, pumps, and multiple sequences allow the user to simulate the disaster at the Chernobyl power plant. (The graphics may look a little rough in Netscape, but it did not crash during testing on the Windows 95 platform.) Click Detailed Applet Description to find the source code, documentation, and other helpful information.

Cross Product Visualization Applet

by Dave McNamara
Contact Info: mcnamara@npac.syr.edu
URL: http://www.phy.syr.edu/courses/ java-suite/crosspro.html
Load Time: Fast
Source Code Included: No

Author's Description: An applet that allows users to manipulate two vectors and observe the change in their vector cross product.

For everybody who's ever craved click-and-draggable physics, set your mouse loose on these vectors and planes. The To See and To Do list provides the mathematically curious with moving three-dimensional results to calculations, along with discussions of the physical principles behind the exercise explained in pretty good regular English.

Impact Simulator 2.0

by John Henckel
Contact Info: henckel@vnet.ibm.com
URL: http://www.intersrv.com/~dcross/impact/impact.html
Load Time: Fast
Source Code Included: Yes

Author's Description: This is a little Java program that simulates the interaction of balls. You can grab the balls with your mouse and drag them or throw them. You can control the forces of friction and gravity. You can make the walls be bouncy or wrap-around. You can simulate planatary systems, rubber balls, Brownian motion, pool table physics, and more. You can turn on trace and make interesting designs. Have fun with it!

The source code, implementation notes, a nicely detailed usage list, and some suggestions for fun things to try are all to be found on this applet page.

Ising Model

by Bernd Nottelman
Contact Info: nottelm@uni-muenster.de
URL: http://planck.uni-muenster.de/java/ising.html
Load Time: Fast
Source Code Included: Yes

Author's Description: This applet simulates an Ising model by a Monte Carlo algorithm (Metropolis algorithm with single spin flip dynamics) at various temperatures (including the critical temperature).

Type in a positive temperature or adjust the mercury level by clicking the mouse, and see the response in a realtime, graphical display. The grid reflects movements on the Hamiltonian and Magnetization graphs. Source is included.

The Lorenz Dynamical System

by Patrick Worfolk
Contact Info: pworfolk@geom.umn.edu
URL: http://www.geom.umn.edu/~worfolk/apps/Lorenz
Load Time: Fast
Source Code Included: No

Author's Description: This applet numerically integrates a set of differential equations and displays the output graphically. The Lorenz equations are a well-studied dynamical system with a strange attractor. The user can start and stop the computation and plot new trajectories in different colors.

Also see the similar/related resources listed in the Education: Math section of this directory.

The Normal Distribution

by David Krider
Contact Info: davidk@fqw.com
URL: http://www.cco.caltech.edu/~ekrider/Finance/BallDrop/BallDrop.html
Load Time: Fast
Source Code Included: No

Author's Description: Part of a project whose purpose is to illustrate basic theoretical finance through the use of interactive applets. This applet illustrates a simple process that gives rise to the normal distribution.

Finance meets basic physical principles-the falling ball/bell curve applet visually demonstrates the principle of normal distribution, which applies to lots more than future cash flow. Neither source code nor significant documentation included, just a basic physics lesson.

Orbit Simulator

by Kelly Jo Brown
Contact Info: kbrown@rspac.ivv.nasa.gov
URL: http://observe.ivv.nasa.gov/observe/exhibit/reference/module/orbits/orbit_sim.html
Load Time: Very Fast
Source Code Included: No

Author's Description: A Java orbit simulator. You can use the mouse to move the satellite into different orbital heights and see the effect on orbital period.

A nice introduction to altitude, orbit, and the placement of satellites. Click the Shuttle button to see a typical space shuttle orbit, or the Geosynch button to see a satellite moving in sidereal time, or, in perfect time with the orbit of the Earth. Other astronomical resources on the Gamelan directory include Phoon and StarGazer (both in Education: Other Educational Resources), and for fun, Cosmix Applet (Web Sites: Commercial).

The Piston

by University of Oregon/Virtual Lab
Contact Info: nuts@moo2.uoregon.com
URL: http://jersey.uoregon.edu/vlab/Piston/piston_frame.html
Load Time: Fast
Source Code Included: No

Author's Description: The Piston is a virtual experiment which demonstrates properties of the Ideal Gas Law. Part of the Virtual Lab (http://jersey.uoregon.edu/vlab).

Read all the instructions before playing with this demo-it is constructed to explode if you screw up (you'll know it when you hear it), and too many screw-ups can make the whole applet crash. Also see the Balloon applet (this section) another physics applet from the Virtual Lab collection.

Rotation-Vibration Spectroscopic Simulator

by Jeff Milton
Contact Info: milton@chem.cmu.edu
URL: http://www.chem.cmu.edu/milton/Java/Spec
Load Time: Fast
Source Code Included: No

Author's Description: The spectroscopic simulator used for describing the rotational and vibrational energies of a spectra. The goal is to combine experimental data with theory. Source is currently not available (it's a bit messy) but will be soon.

If you need to brush up on the basics of quantum mechanics before jumping into this applet, the author has helpfully provided lots of such stuff in the index frame.

Other Educational Resources

3D Stereo Pair Modeler

by Timothy W. Macinta
Contact Info: twm@mit.edu
URL: http://www.mit.edu/people/twm/strobe/modeler.html
Load Time: Medium Fast
Source Code Included: Yes

Author's Description: This applet is capable of extracting 3-D data stored in a pair of stereo images. If you don't know what a stereo pair is, take a look at this page for an explanation.

Plot points on the stereo pair of images in the demo and rotate them using your mouse and the letter-key commands provided by the author. It's somewhat difficult to get the full effect since it takes a much bigger than average screen to view the entire thing without scrolling and sliding around. But watching the points rotate around the axis at the bottom is neat-the more you plot, the more interesting it gets.

Airport Pattern Simulator

by Robert Temple
Contact Info: templer@db.erau.edu
URL: http://www.db.erau.edu/java/pattern
Load Time: Fast
Source Code Included: Yes

Author's Description: A demonstration program for a simplistic simulation of aircraft arrivals to a single runway.

Watch the airplanes circle, land, taxi, and park in the hangar. And download the source code if you want it.

Chesapeake Bay Observing System

by Brian Guarraci
Contact Info: webmaster@seabeast.hepl.cees.edu
URL: http://cbos.hepl.cees.edu
Load Time: Very Fast
Source Code Included: No

Author's Description: An application of Animator in a realtime data display environment. Used to illustrate that the realtime engine is running.

This applet processes information from buoys and other sensors in the Chesapeake Bay region that test the sea's temperature, wind speed, salinity, and more. Users select the time period and the specific buoy archive they want to access, and the applet produces a spreadsheet detailing the results to be downloaded. Also see the Java Interface Realtime TAO Data applet for a similar program measuring buoy data in the tropical Pacific, along with TAO SST and Wind Animation (Multimedia: Animation).

Color Perception

by Adam Doppelt
Contact Info: amd@cs.brown.edu
URL: http://www.cs.brown.edu/research/graphics/projects/igi/spectrum
Load Time: Fast
Source Code Included: No

Author's Description: Interactive illustration of color perception. A wonderful example of how the Java language can be used to illustrate complex processes using interactive graphics.

This physics/computer graphics resource is peppered with interactive illustrations generated by applets-Illustration 1, for example, depicts changes in frequency when the user clicks and drags the mouse across the blank, top-most graph. As with CLens (Multimedia: Graphics Resources). Java is used here in combination with other disciplines to make an interesting, user-friendly tutorial. It's cool!

Curve Applet

by Michael Heinricks
Contact Info: heinrica@cs.sfu.edu
URL: http://fas.sfu.edu/1/cs/people/GradStudents/heinrica/personal/curve.html
Load Time: Very Fast
Source Code Included:Yes

Author's Description: The applet allows manipulation of control points for various types of curves: hermite, Bezier, and b-spline.

Plot points and draw curves. Also take the source code and the original executable, as generously provided by the author.

Earth Density

by Charles Angevin
Contact Info: angevine@uwyo.edu
URL: http://gilbert.uwyo.edu/earthDensity.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: Earth Density is a Java applet in which the user tries to create a density model that matches Earth's mass, radius, and moment of inertia. The object of the exercise is to show students how geologists infer the composition of parts of the planet that are too deep to sample directly.

This very cool applet allows users to play with different crust, mantle, and core thicknesses and to see their estimates drawn out as real on a model of the Earth. The applet calculates mass and moment of inertia based on the user's guesses. Audio capability can be switched on or off.

Equation Renderer

by Robert Miner
Contact Info: webmaster@geom.umn.edu
URL: http://www.geom.umn.edu/~rminer/jmath
Load Time: Fast
Source Code Included: Yes

Author's Description: The Equation Renderer typesets mathematical equations described in HTML 3.0 passed as a parameter line. At the moment, it only recognizes a few or the math tags, but it's a start.

Link to many home pages featuring this applet in action, or download it and create your own mathmatical masterpiece. Documentation and information about authoring tools are included.

Exploring Emergence

by Mitchel Resnick and Brian Silverman
Contact Info: mres@media.mit.edu, bss@media.mit.edu
URL: http://el.www.media.mit.edu/groups/el/projects/emergence
Load Time:
Source Code Included: No

Author's Description: This collection of pages is an example of an active essay-an essay with manipulable computational objects embedded in the text. It integrates a discussion of emergence with cellular-automata simulations that allow readers to explore emergent phenomena.

Epistemology at its finest-these pages explore both Seeds and Life worlds in clear, concise English. There are a number of related resources in the Gamelan directory that build upon the basic premises begun here: Biomorphs (Education: Biology) the Pentomino Puzzle Solver (Art and Entertainment: Puzzles) and Conway's Game of Life and Life's Game in Java (both Art and Entertainment: Life Games), and Bram's JavaScript Life Page (JavaScript: Games).

FFT Applet

by Calum Smeaton, David Nicol, and Gopal Chand
Contact Info: calum@virtual-inn.co.uk
URL: http://www.virtual-inn.co.uk/orbit/beta/fft
Load Time: Medium Fast
Source Code Included: Yes

Author's Description: Fast Fourier Transform calculates an FFT modulus of a simple wave form described by the user with sample points.

Don't scroll down while the applet is loading or you may have to invoke a refresh in your window manager before you start moving points. Also, click a blank part of the game field to activate the power spectrum.

Foul

by Yosef Cohen
Contact Info: yc@turtle.gis.umn.edu
URL: http://turtle.gis.umn.edu/people
Load Time: Very Fast
Source Code Included: Yes

Author's Description: A simulation of a real-world ecosystem that develops on submerged oceanic surfaces. The program deals with the problem of marine biofouling and its biological control. If adopted, the approach will help prevent further pollution of oceans by Tribulytin (one of the most toxic compounds introduced to waterways). Includes Monte-Carlo simulations of a Poisson process.

Explore a natural solution to poisoning Earth's oceans and waterways-in this applet simulation, the user determines how many limpets are needed to fight barnacle growth, preventing the need for toxic paints and other chemicals. Some of the text in the parameters window had dropped out during testing on the Windows 95 platform, but this didn't affect the demo's performance.

Genetic Algorithm Demo

by Marshall Ramsey
Contact Info: mramsey@as.arizona.edu
URL: http://nicmos2.as.arizona.edu/~mramsey/ga.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: A graphical demonstration of a genetic algorithm with the ability to dynamically change parameters. Also includes a brief introduction to GAs.

Watch genes change and evolve as this applet keeps track of each generation's fitness, improvement, and more. Users select the number of agents and genes, plus the rate of mutation and crossover, by clicking-and-dragging the slider bars. Source code and documentation are included.

Guitarist's Chord Dictionary

by Joe Heitzeberg
Contact Info: joeh@cs.washington.edu
URL: http://www.emedia.org/chord.html
Load Time: Fast
Source Code Included: No

Author's Description: Guitarist's Chord Dictionary is a Java applet reference of over 250 chords containing full tablature representations and sound recordings. It is brought to you by the folks at eMedia, makes of the popular CD-ROM eMedia Guitar Method.

An outstanding and invaluable reference for the beginning guitarist. Type a chord into the text window, see the position, and arrow down for all related minor, augmented, diminished, and other chords. The applet will also play the chord for you if you like.

The Interactive Mandelbrot Set

by Christine Anthony, Gordon Madsen, and Jacon Carlyon Running
Contact Info: webmaster@franceway.com
URL: http://www.franceway.com/java/fractale/mandel_b.htm
Load Time: Fast
Source Code Included: No

Author's Description: This applet will compute and draw the Mandelbrot set on your screen. You will be able to zoom into the figure and discover its fractal properties.

This applet has some trouble interacting with Netscape-on both the Windows 95 and Macintosh testing platforms, the upper and lower portions of the Mandelbrot window were sheared off though the browser did not freeze during computation. Other Mandelbrot-related resources on the Gamelan directory include Java Man (Multimedia: Graphics Resources), Mandelbrot Escape Iterations (Education: Math), and The Mandelbrot Set (Multimedia: Graphics Resources).

Interactive Sentence Builder

by Jeff Bauer
Contact Info: jtbauer@scri.fsu.ed
URL: http://www.scri.fsu.edu/~sentence.html
Load Time: Fast
Source Code Included: Yes

Author's Description: Build a sentence and watch it be acted out! HotJava.

The twenty-first century equivalent of Dick and Jane-this applet does what it says and does it beautifully, without glitches or hesitations on either the Windows 95 or the Macintosh testing platform. Other word games on the Gamelan directory include Cryptarithms (JavaScript: Games), Word Search Applet (Art and Entertainment: Puzzles), Crossword Puzzle in JavaScript (JavaScript: Games), Crossword Puzzle (Art and Entertainment: Puzzles), and Cypherspace (JavaScript: Games).

Java Courseware

by Robert Elmore
Contact Info: elmore@uol.com
URL: http://dev.uol.com/~elmore/javademo/menu2.html
Load Time: Very Fast
Source Code Included: No

Author's Description: We are in the process of converting a library of courseware into Java for delivery via the web.

Interactive courseware for understanding accounting principles-four groups of pages cover balance sheets, income statements, financial statements, and fund flow statements. The author recommends using Netscape for Windows 95/NT or appletviewer.

Java Interface to Realtime TAO Data

by Stefan Zube and Dai McClurg
Contact Info: zube@pmel.noaa.gov, dai@pmel.noaa.gov
URL: http://www.pmel.noaa.gov/toga-tao/java/taoinfo.html
Load Time: Fast
Source Code Included: No

Author's Description: Java interface to realtime climate data from the Tropical Atmosphere Ocean (TAO) network of moored ocean buoys in the tropical Pacific.

Choose a context map by clicking-and-dragging down the scrolling menu to activate the data field, compare buoy-specific information, and more. Also see TAO SST and Wind Animation (Multimedia: Animation), and the Chesapeake Bay Observing System applet (Education: Physics) for information on a similar applet measuring buoy data collected off the Massachusetts coastline.

Figure 4.14:

Juggling

by Chris Seguin
Contact Info: seguin@uiuc.edu
URL: http://www.acm.uiuc.edu/webmonkeys/juggling
Load Time: Very Fast
Source Code Included: Yes

Author's Description: Three nifty animations teach you how to juggle.

This applet really is nifty, and it runs in realtime, too. Source code and some documentation is included.

Figure 4.15:

The Latest Weather

by Joel Plutchak
Contact Info: plutchak@uiuc.edu
URL: http://storm.atmos.uiuc.edu/java
Load Time: Very Fast
Source Code Included: No

Author's Description: None.

The user can view the variables almost immediately by clicking the checkboxes. Also, the new measurements scroll in from the top to overlay the previous map for a comparative view. Click an Info box for more details on any particular map variable. Other weather-related resources on the Gamelan directory include Blue Skies Java Weather Browser (Miscellaneous: Other Miscellaneous Resources), Weather Forecast for the Next 12 Hours (Multimedia: Graphics Resources), Satellite Animation (Multimedia: Animation), and Atlantic Hurricane Tracking (Web Sites: Commercial Sites).

Figure 4.16:

Learn to Dance

by Georg Hessmann
Contact Info: hessmann@informatic.uni-hamburg.de
URL: http://tech-www.informatik.uni-hamburg.de/dance/JDance-e.html
Load Time: Medium Fast
Source Code Included: Yes

Author's Description: Demonstrates some basic dance figures (slow waltz, tango, slow fox, foxtrot) in realtime with audio. The link above is to the English version-there's also a German version (http://tech-www.informatik.uni-hamburg.de/dance/JDance.html).

This applet loaded very slowly after needing two reloads on the Windows 95 testing platform. On the Macintosh, the rhythm and audio features were somewhat choppy, but everything else worked beautifully. The source code and relevant documentation is available.

Limaçons

by William Lelar
Contact Info: wm@cris.com
URL: http://www.cris.com/~wm/lime.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: An interactive applet that draws simple geometric figures called limaçons.

Adjust the four given parameters-sample rate, sine wave frequency, number of revolutions, and DC offset-to produce unique geometric forms, or click the Random button. The results look similar to Live Cycloide (Multimedia: Graphics Resources), Greg Linden's Home Page (Special Effects: Other Special Effects Resources), Spirograph (Multimedia: Graphics Resources), Liny (Special Effects: Other Special Effects Resources), Sliding Lines (Programming: Graphics), Squiral (Art and Entertainment: Other Art and Entertainment Resources), http://www.streetside.com (Special Effects: Other Special Effects Resources), and Snowflake Applet (Art and Entertainment: Other Art and Entertainment Resources).

Noise Sphere Applet

by Chuck McManis
Contact Info: cmcmanis@netcom.com
URL: http://www.golfweb.com/cmcmanis/noise.html
Load Time: Very Fast
Source Code Included: Yes

Author's Description: This applet generates a "noise sphere" which is a way of visualizing how good a random number generator is. This can be especially useful when evaluating a random function for cryptographic applications.

Simple, easy-to-use applet, based on information ported from a C++ noise program-the more you click the picture, the more points appear. Source code and some documentation available for free.

Non monotonic Logic (Tweety Example)

by Robert Jeansoulin
Contact Info: Robert.Jeansoulin@lim.univ-mrs.fr
URL: http://protis.univ-mrs.fr/~jeansoul/Tweety.html
Load Time: Very Fast
Source Code Included: No

Author's Description: A short demo of non-monotonic logic based on the popular Tweety example. Uses threads to implement logical rules (classic modus ponens and Reiter's defaults) and their casual revision.

This applet runs the simple, classic programming/logic puzzle known best by the same name. An explanation of the principles behind the puzzle are given, but no source.

Overlayer Prototype

by Marty Wachter
Contact Info: mrw@welch.jhu.edu
URL: http://infonet.welch.jhu.edu/~mrw/overlayer
Load Time: Very Fast
Source Code Included: No

Author's Description: This applet displays a canvas panel on the left and a list panel on the right. Selecting an item in the list displays the area overlayed on the base image using a transparent GIF file.

Another example of Java's usefulness, utilizing medical imagery and information as illustration-see also the Whole Brain Navigator (Education: Medicine) and PickTest2 (Programming: User Interfaces) for similar use of X-rays, scans, and specimens in partnership with Java. E-mail the author for the source code.

Phoon

by Jef Poskanzer
Contact Info: jef@acme.com
URL: http://www.acme.com/java/software/Phoon.html
Load Time: Fast
Source Code Included: Yes

Author's Description: Shows the current PHase of the mOON.

An absolutely beautiful glimpse of the moon, including a partial peek at the dark side illuminated by the Earth reflecting the sun. Other astronomical resources on the Gamelan directory include Orbital Simulator (Education: Physics), StarGazer (this section), and for fun, Cosmix Applet (Web Sites: Commercial).

Figure 4.17:

Sampling Distributions from Statistics

by Suresh Srinivasan
Contact Info: suresh@thomtech.com
URL: http://www.thomtech.com/~suresh/java/sample.html
Load Time: Fast
Source Code Included: Yes

Author's Description: Illustrates elementary sampling theory using animation for a variety of statistical distributions.

A visual illustration of the relationship between means, population, and sample size. Choose from three distributions and click Start to run the applet. Source code is included.

SolarPop

by J. Craig Cleaveland
Contact Info: craig@thuntek.net
URL: http://www.millenial.org/~ccleave/solarpop2
Load Time: Very Fast
Source Code Included: No

Author's Description: A simulation of solar system demographics of the next millennium. How fast will humanity move out to space, the moon, the asteroids. You can set various demographic and technical parameters and then watch history in the making.

Detailed documentation lists the parameters of this experiment, assumptions and exclusions, and other specifics about how this applet does its thing. PC users have apparently experienced trouble with inaccurate graphs, bad colors, and other bugs, so modify your expectations accordingly if necessary. If you're looking for an actual night sky to appreciate, check out Phoon (this section), Orbital Simulator (Education: Physics), StarGazer (this section), and for fun, Cosmix Applet (Web Sites: Commercial).

StarGazer

by Alden Bliss
Contact Info: alden@oz.net
URL: http://web.smart.net/~tasanan/sky.html
Load Time: Medium Fast
Source Code Included: No

Author's Description: A dynamic view of the night sky.

A few minutes' patience is required while this applet loads up. Then you can choose your view by specifying a time, date, and general latitude to explore the evening sky. The Constellations On setting is especially cool. Other astronomical resources on the Gamelan directory include Phoon (this section), Orbital Simulator (Education: Physics), and for fun, Cosmix Applet (Web Sites: Commercial).

State Machine Simulator

by Kyril Faenov
Contact Info: kxf@cse.ogi.edu
URL: http://www.cse.ogi.edu/~kxf/Simulator.html
Load Time: Fast
Source Code Included: Yes

Author's Description: A drag-and-drop finite state machine editor/simulator. You can add/remove states and transitions, setup input strings, and step through the state changes. Supports saving and loading of the designs (when ran locally).

This demo is accompanied by an excellent feature-by-feature explanation of each toolbar function, which users should read before trying to figure things out by trial and error. Source and applet distribution permission are both free.

Figure 4.18:

Sunclock

by Ed McCreary
Contact Info: forge@neosoft.com
URL: http://www.NeoSoft.com/~forge/java/Sunclock/Sunclock.html
Load Time: Medium Fast
Source Code Included: No

Author's Description: Displays a view of the earth and the current area illuminated by the sun. Image is updated every minute. Requires Netscape 2.0 b4 or greater.

Flat map of the earth divided into regions of daytime and nighttime. For comparison, see the Sun Clock applet (Utilities: Clocks) which provides the same information as seen from space.

TIG Domain Map

by Robert Armstrong
Contact Info: robert@tig.com
URL: http://thunder.tig.com/~robert/domainmap.html
Load Time: Fast
Source Code Included: No

Author's Description: An interactive map that displays domain information by state.

The actual information given by this applet demo is outdated (current as of mid-November 1995) but the "new" domain page would not load up on the Windows 95 testing platform so the old page had to suffice. Roll the cursor over a particular state to get the number of .com, .net, .org, and .edu domains in that area. The page also includes a nationwide ranking comparing all 50 states.