FOIA on Martin Luther King

Read from the scan by GLM-OCR; expect the odd misread word.

show the area around a roof is weakening, it can be supported by beams or roof bolts."

In seismic exploration, a high energy explosion is set off, and sensitive instruments determine the structure and makeup of surrounding land by recording how fast the shock waves travel through the ground. The waveforms can be interpreted to pinpoint probable deposits of oil, and to describe rock formations. "Using a large energy souce like an explosion in a mine is out of the question," Dr. Podio said, "so a manually controlled impact device was designed to generate the shock waves." The impact device, which works like a BB gun, uses air pressure to shoot a round projectile at a striker plate mounted at the end of the barrel.

When the striker plate is pressed against the wall or roof of the mine and the device is triggered, shock waves are sent through the surrounding rock. The shock waves are picked up by wideband transducers, digitized by a fast transient recorder, and processed through the Nova 820 for waveform enhancement. The waveform is then displayed on an oscilloscope, with the results of velocity and depth calculations. Permanent records of the waveform can be made on paper tape, or by transmitting the data to a large scale remote computer.

"A mine could make daily checks with the system to detect changes in rock strata as the working face of the mine advances." Dr. Podio said, "or the system could be transported throughout the mine to make daily checks on the condition of roofs at predetermined key locations." Dr. Podio noted that similar systems could be used to predict the quality of rock in rapid excavation projects or could be used in nondestructive tests of large concrete structures.

## PHONE BOOKS BY COMPUTER

Peter A. Cassels

Bell Telephone Laboratories

Mountain Ave.

Murray Hill, N.J. 07974

The Bell System is using computer technology to modernize production of the White Pages telephone books. A system designed to improve customer service, control costs and streamline massive recordkeeping operations is now being implemented. The system called DIR/ECT (for DIrectory project) was developed by Bell Laboratories, the research and development unit of the Bell System. Michigan Bell Telephone Company recently issued its first directory containing listings produced by the system. Michigan Bell also is using the system to produce some of its directory assistance records.

DIR/ECT is a more sophisticated outgrowth of its prototype, PHOTAC, a similar process developed by the New York Telephone Company under sponsorship of the nationwide Bell System. The first directory produced by the PHOTAC system was distributed in 1966. Since then, New York Telephone has converted some 4.5 million listings to the process. Currently the 12 major downstate White Pages directories are produced by PHOTAC.

The DIR/ECT system stores in a computer memory directory information such as the customer's name, address, telephone number even telephone book delivery instructions. The information in the computer memory then is fed into a device called a photocomposer, which provides ready-to-print listings for White Pages. Besides the annual White Pages directories, DIR/ECT produces daily updates of

new listings and monthly reprints for the telephone companies' directory assistance operators.

Although customers may see no obvious differences in the computer-produced directory, listings are easier to read and pages cleaner looking. The directories also have uniform abbreviations. The system has built-in cross-checks for consistent spelling of street names and for obvious errors in street and telephone numbers. There also is provision for massive directory listing changes, caused by renaming of streets and buildings.

Today, listings for phone directories are generally set line-by-line in metal type. Changes in listings must be reset and inserted by hand. With the new system, changes can be made quickly (because information is stored on magnetic computer tape and not metal type), the need to store tons of lead type will end, and the growing cost of publishing directories will be lessened.

## EDUCATION NEWS

## M.I.T. MUSIC PROJECT USES DEC COMPUTER

News Office

Cambridge, Mass. 02139

The Massachusetts Institute of Technology has begun work on a project aimed at making the Institute a major center for the study and composition of electronic music. Barry Vercoe, assistant professor of music, working with a computer given to the Department of Humanities' music section by Digital Equipment Corp. of Maynard, is in the early stages of developing a major electronic music production facility at the Institute.

Professor Vercoe said the computer facility "will be a tool both in the hands of the teacher and the composer that will greatly aid the development of creativity. The facility also will provide an excellent tool in the teaching of musical composition for conventional instruments.

"This is definitely not a scientific project. I'm not interested in merely getting a computer to sound exactly like a trumpet. The technological application, however, will interest some students who might not approach music otherwise and some of these will be drawn into its aesthetic considerations, through the back door as it were," Professor Vercoe said.

## Why compose music for a machine at all?

"I suppose someone asked that very question when man first composed music for what are now traditional instruments, instead of for the human voice alone." Professor Vercoe said. "Electronic music merely expands the forces available to the practicing composer."

The PDP-11/45 computer — coupled with music input — also will lend itself to other forms of music research, such as syntactic analysis of music structures.

Professor Vercoe is the author of the widely used Music 360 language for digital sound synthesis. He has taught at M.I.T. for two years and is director of the Experimental Music Studio. His work, "Metamorphoses for Orchestra," was given its Boston premier early this year by the M.I.T. Symphony and was performed by the orchestra on its subsequent nation-