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Communications of the ACM

Table of Contents


ACM Vice President Ralston comments on: committees, committees, committees


Signature simulation and certain cryptographic codes

Three cyphers allegedly authored by Thomas Jefferson Beale in 1822 have been the subject of intensive study for over 100 years. Generations of cryptanalysts have expended untold man-years, thus far without success, attempting …

Pattern width at a given angle

That the pattern feature “width as a function of angle” possesses several possible interpretations is demonstrated in this paper, which is a review of the width concept in pattern recognition and the geometrical concept itself …

The reconstruction of binary patterns from their projections

Given the horizontal and vertical projections of a finite binary pattern f, can we reconstruct the original pattern f? In this paper we give a characterization of patterns that are reconstructable from their projections. Three …

A language for treating geometric patterns in a two-dimensional space

In this paper CADEP, a problem-oriented language for positioning geometric patterns in a two-dimensional space, is presented. Although the language has been specifically designed for the automatic generation of integrated circuit …

Construction of rational and negative powers of a formal series

Some methods are described for the generation of fractional and negative powers of any formal series, such as Poisson series or Chebyshev series. It is shown that, with the use of the three elementary operations of addition,  …

Comments on prevention of system deadlocks

Habermann's method of deadlock prevention is discussed, where deadlock is defined as a system state from which resource allocations to certain processes are not possible. It is shown that the scheduler may introduce “artificial” …

Proof of a program: FIND

A proof is given of the correctness of the algorithm “Find.” First, an informal description is given of the purpose of the program and the method used. A systematic technique is described for constructing the program proof during …

Further evidence for the analysis of algorithms for the zero-one programming problem

The purpose of this note is to report computational experience additional to that recently summarized by Gue et al., with two algorithms for the zero-one linear programming problem. An error in Gue's paper is corrected. The utility …

Complex gamma function


Circular integer partitioning


Minit algorithm for linear programming

In his Certification of Algorithm 245 [1], Ralph L. London exhibits a common confusion between an algorithm, its representation, and its implementation on a processor—a code. In the present state of the art we can attempt, in …

Comment on London's certification of algorithms 245

In his Certification of Algorithm 245 [1], Ralph L. London exhibits a common confusion between an algorithm, its representation, and its implementation on a processor—a code. In the present state of the art we can attempt, in …

Comment on the conversion of decision tables to computer programs

In their article [2] C. R. Muthukrishnan and V. Rajaraman have developed two excellent algorithms for conversion of limited entry and mixed entry decision tables to computer programs. I must, however, take issue with their contention …