Sign In

Communications of the ACM

Table of Contents

President's letter to the ACM membership: let's face it

Editorial: on the ACM publications

It is proper that a professional organization periodically review its publication policy to ensure that it is fully meeting its responsibilities to its members To this purpose the President of ACM has asked the Editorial Board …

Analysis of boolean program models for time-shared, paged environments

Directed graphs or their associated matrices are frequently used to represent the logical structure of sequences of computer instructions. Such techniques are used and, in addition, data references are represented in a nondirected …

An algorithm for hidden line elimination

The algorithm presented causes the elimination of hidden lines in the representation of a perspective view of concave and convex plane-faced objects on the picture plane. All the edges of the objects are considered sequentially …

Algorithm 348: matrix scaling by integer programming [F1]

Algorithm 349: polygamma functions with arbitrary precision [S14]

Simulation of outpatient appointment systems

An experimental computer program is described which simulates appointment systems employed by outpatient departments of hospitals. Both major kinds of appointment systems—individual and block—can be simulated. The purpose of  …

On coordination reduction and sentence analysis

A class of coordination phenomena in natural languages is considered within the framework of transformational theory. To account for these phenomena it is proposed that certain machinery be added to the syntactic component of …

An algorithm for solving a special class of tridiagonal systems of linear equations

An algorithm is presented for solving a system of linear equations Bu = k where B is tridiagonal and of a special form. This form arises when discretizing the equation - d/dx (p(x) du/dx) = k(x) (with appropriate boundary conditions) …

Computation of Jn(x) by numerical integration

It is shown to be practical to compute Jn(x) by numerical integration of its integral representation using the trapezoidal rule. The error in this approximation was studied empirically.