start e-lecture 1 (alpha testing version of lecture 1)
preliminary version: comments are very welcome!

Computer requirements

minimal configuration (full content but lacking some amenities: transcription instead of sound, ascii equations):

for full functionality (including audio, my picture, and typeset equations)


So far, I have implemented the material in the first lecture of my Investments mini (half-semester course). A typical slide has

The idea of having both audio clips and exact transcriptions is:

The idea of having my picture at the left of the audio clips is to make this appear like the picture of the reporter in newscasts from remote locations that do not have video. This is an attempt to give a personal touch in spite of using very stable and widely available technology.

Known problems

This list is short, but perhaps only because I don't have much experience yet. If you have problems, please let me know. Details about what computer, browser (including the version) and computer (including the operating system version) you have will help me to duplicate and fix the problem. I think it is good generic advice for using the web to keep your browser reasonably up-to-date. Getting a new browser may fix problems with broken graphics or sound.

My general approach

I want to learn about CBT (computer-based training) materials in association with the investments course I am teaching. My intent is to produce materials that are simple and robust, and in particular

  1. The materials should work on any reasonably modern web browser, without plug-ins.
  2. The materials should work on any brand of computer.

These simple requirements rule out all current video technology (which is still somewhat flaky) and many environments that are dependent on a particular operating system (there are many CBT packages that work only on MACs or only on Windows). They also rule out javascript, since javascript is not standardized. Most sites using javascript will crash on at least one of my machines at home. Even the current e-lecture I am using (which has java applets for playing sounds) does crash the browsers occasionally; I am not sure it is the fault of the java implementation or just inherent instability in current browsers. It seems to be less of a problem when I view the materials locally and not over the web. This suggests that using a cd-rom for delivery, which will make the audio loading much faster, will also minimize browser problems.

To allow quick development, the current e-lecture stays very close to my existing lectures. This approach allows me to get started quickly even if it does not exploit the full potential of the new medium.

Technical comments, or how I put it together

Mostly, the lecture uses plain-vanilla HTML (hypertext mark-up language) pages. HTML is the standard language for web pages. Many word processors will produce HTML files that can be mounted on the web but are defective and will not work on different computers and browsers. (Now, why would some companies want to do that?) I prefer to produce my own HTML files from scratch using a text editor; by staying within the standard (and staying away from font tags and other nonstandard extensions), it is easy to create very robust web pages. There are obviously many books available on this subject; I like the NCSA (at UIUC) Beginner's Guide to HTML. I also recommend the free program HTML TIDY for checking HTML for errors and compatibility with standards. I have not tried it this way, but I think HTML TIDY is actually supposed to salvage HTML files produced by Microsoft Word so it can be read in different browsers besides Internet Explorer.

For embedding equations that use non-ascii characters, I use PNG (portable network graphics) instead of GIF graphics. This is slightly unfortunate, because many older browsers support GIF graphics but not PNG graphics. However, PNG graphics are superior both technically and legally. To quote the informal history on the PNG site, ``PNG was designed to be the successor to the once-popular GIF format, which became decidedly less popular right around New Year's Day 1995 when Unisys and CompuServe suddenly announced that programs implementing GIF would require royalties, because of Unisys' patent on the LZW compression method used in GIF.'' All reasonably modern browsers support PNG graphics, so I don't think using PNG graphics should be a big imposition to anyone. If your browser is old enough that it doesn't support PNG, you will probably appreciate an upgrade for general web browsing and not just for viewing my materials.

To make the .png files, I have used some standard TeX/LaTeX tools (including dvips -E) and a wonderful public-domain program ImageMagick, that can be used to convert images to different formats. TeX and LaTeX are public-domain tools that produce very high quality typesetting that can accomodate very sophisticated setting of equations. The program dvips produces (normally) black text on a white background; I use the -colorize options of ImageMagick's convert command to change the background from white to the same off-white color as I use in my slides.

To play the audio files, I was hoping to find a standard audio format that is supported by all modern browsers. However, a quick survey of machines at my house suggest there is no such supported audio format. Given that I do not want to use plug-ins (which can be flaky, and in any case the need to download a plug-in will deter some users), I wrote a short java program based on the SoundExample class described in the java tutorial. This uses only very early (version 1.0) commands, and is therefore should run on all java-enabled browsers. There are new java multimedia commands that are more sophisticated, but they seem to require users to download new plug-ins before they can be used. To generate the audio (.au) files, I use the audiotool command on my SUN; I suspect this may be a standard X-windows command. In the command, I used voice quality (which I thought would be adequate) given that the files are large even with this setting. I did not use any compression, thinking compression might reduce compatibility. Exploring the use of compression is one way to go. Instead of using the type of crystal microphone that comes with the computer, I used a professional microphone (EV N/D257B) and mixer (Mackey 1202) I use for music. I should add that I have no reason to think this microphone is optimal for this task.

The icons in the program use xbm (X-windows bit map, perhaps?) files generated by the icon editor in CDE on my SUN. These are really primitive (2-color and coarse) but allowed me to get started quickly. Sooner or later, I plan to have more stylish icons (perhaps with the assistance of my older daughter Megan).