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STANFORD -- A scientist spends weeks, maybe months, computing and analyzing data that lead to a single graph or illustration in a publication. A colleague or student would like to reproduce this analysis for verification and use, but reproducing the work takes almost as much time as producing it in the first place.

Jon Claerbout, a Stanford University professor of geophysics, believed this to be an insoluble problem "hopelessly mired in human nature." Then he accidentally found a solution while editing his most recent textbook.

Like other computer users, Claerbout routinely moved sections of text through a series of "copy" and "paste" commands. He decided, however, to take that concept one step further. He assembled his textbook onto a compact disc (CD-ROM) to be used in conjunction with its paper-and-ink counterpart. For it, he "copied" entire software programs that had created a specific illustration and "pasted" those programs into his electronic textbook.

The result is a textbook that comes alive. Using a boxed-in key that corresponds to an illustration, a reader can simply push a button to rebuild or change that illustration. Because the original parameters and formulas are included, they can be be manipulated, making the electronic textbook a research tool.

"The paper is the advertisement of the scholarship," Claerbout said. "The electronic medium is the scholarship itself."

Claerbout's research is in reflection seismology and his textbook, Earth Soundings Analysis: Processing Versus Inversion., concerns the recording and analysis of echo soundings of the earth, which the petroleum industry uses for exploration drilling.

The electronic textbook, titled SEP-CD-1, contains geophysical maps that model these soundings. Some of the illustrations are in color, some are interactive and some are even viewed as motion pictures. Students are able to explore, modify and experiment with theoretical concepts previously clouded by mystery.

Could electronic technology replace books as we know them?

"I think we all agree no one wants to read a book from a screen," Claerbout said. But the computerized version contains more depth and clears the way for a vast and speedy exchange of knowledge.

An engineer, for instance, might place all the calculations underlying a bridge design behind a drawing of it, he said. Another engineer or student could change those and the figure would automatically be redrawn on the screen.

Claerbout seeks to have his research group join with others at Stanford - in such fields as economics, sociology, engineering and business - in establishing a standard structure for reproducible research in electronic documents. Because of copyright laws, the software used must be in the public domain or under the author's control. "The type of software is not relevant to the reproducibility of documents," Claerbout said. "It is the clarity of the computer directory and the structure of the computer file that are key to making the electronic textbook useful."

Software for Claerbout's electronic textbook was written in LaTex for use with the three most popular UNIX workstations: IBM- RS-6000, Sun 4 and DEC 3100. Assembled by Claerbout and doctoral student Martin Karrenbach, it is available for $15 plus $2 for shipping and handling through the Stanford University Press.

In addition to the textbook, the CD-ROM includes the thesis of former student Joe Dellinger, Anisotropic Seismic Wave Propagation, and two 1991 Progress Reports from the Stanford Exploration Project. This industrial affiliates program produces research by 20 geophysicists and students. Founded by Claerbout in 1973, the project has served as a model for funding geophysics research at universities nationwide.



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