acm-header
Sign In

Communications of the ACM

Table of Contents


ACM President's letter: relation of ACM to the world outside ACM


Semantic evaluation from left to right

This paper describes attribute grammars and their use for the definition of programming languages and compilers; a formal definition of attribute grammars and a discussion of some of its important aspects are included. The paper …

On self-organizing sequential search heuristics

This paper examines a class of heuristics for maintaining a sequential list in approximately optimal order with respect to the average time required to search for a specified element, assuming that each element is searched for …

Permutation enumeration: four new permutation algorithms

Classical permutation enumeration algorithms encounter special cases requiring additional computation every nth permutation when generating the n! permutations on n marks. Four new algorithms have the attribute that special cases …

An application of heuristic search methods to edge and contour detection

This paper presents a method for detecting edges and contours in noisy pictures. The properties of an edge are embedded in a figure of merit and the edge detection problem becomes the problem of minimizing the given figure of …

A stochastic evaluation model for database organizations in data retrieval systems

Experimental work in the valuation of large scale data retrieval systems has been scarce due to its difficulty and prohibitive cost. This paper discusses a simulation model of a data retrieval system which has the effect of significantly …

A counterintuitive example of computer paging

A counterexample is exhibited to a natural conjecture concerning the optimal way to group records into pages in the independent reference model of computer paging (an organization is said to be optimal if the “least recently  …

A fast division technique for constant divisors

A fast algorithm for division by constant divisors is presented. The method has proved very useful implemented as microcode on a binary machine, and can be adapted directly into hardware. The mathematical foundations of the algorithm …

ACM Forum: letters