August 1974 - Vol. 17 No. 8
Features
A new technique for compression and storage of data
The widespread tendency toward storage of large programs and blocks of text has produced a need for efficient methods of compressing and storing data. This paper…
A user authentication scheme not requiring secrecy in the computer
In many computer operating systems a user authenticates himself by entering a secret password known solely to himself and the system. The system compares this password…
A high security log-in procedure
The protection of time sharing systems from unauthorized users is often achieved by the use of passwords. By using one-way ciphers to code the passwords, the risks…
Execution time requirements for encipherment programs
Although encipherment has often been discussed as a means to protect computer data, its costs are not well established. Five experiments were conducted to measure the cpu…
Graph coloring conditions for the existence of solutions to the timetable problem
A necessary and sufficient condition is presented for the existence of a solution to the Gotlieb class-teacher timetable problem. Several relationships are established…
A new solution of Dijkstra’s concurrent programming problem
A simple solution to the mutual exclusion problem is presented which allows the system to continue to operate despite the failure of any individual component.
On the conversion of programs to decision tables: method and objectives
The problems of converting programs to decision tables are investigated. Objectives of these conversions are mainly program debugging and optimization in practice.…
Gauss harmonic interpolation formulas
Let R be an open, bounded, simply connected region in the (x,y)-plane and let (x*,y*) be a point in R. Assuming R is starlike with respect to (x*,y*), we discuss a method…
Interpolation with rounded ramp functions
A new interpolation function is introduced. It has infinitely many continuous derivatives and is a composition of ramp functions with smoothed bends called Rounded Ramp…
Recurrence relations for the Fresnel integral 0∞exp -ctdtt 1+t2
The class of functions defined by ∫∞0[exp(-cX)dt/(1 + Y) (√t)k] where X and Y are either t or t2 and k is -1, 0, or 1 can be evaluated by recurrences for…