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Communications of the ACM

Table of Contents


ACM President's Letter: problems, problems!


A fast algorithm for copying list structures

An algorithm is presented for copying an arbitrarily linked list structure into a block of contiguous storage locations without destroying the original list. Apart from a fixed number of program variables, no auxillary storage …

A language extension for expressing constraints on data access

Controlled sharing of information is needed and desirable for many applications and is supported in operating systems by access control mechanisms. This paper shows how to extend programming languages to provide controlled sharing …

Test data as an aid in proving program correctness

Proofs of program correctness tend to be long and tedious, whereas testing, though useful in detecting errors, usually does not guarantee correctness. This paper introduces a technique whereby test data can be used in proving …

Automatic data structure selection: an example and overview

The use of several levels of abstraction has proved to be very helpful in constructing and maintaining programs. When programs are designed with abstract data types such as sets and lists, programmer time can be saved by automating …

Incorporation of units into programming languages

The issues of how a programming language might aid in keeping track of physical units (feet, sec, etc.) are discussed. A method is given for the introduction of relationships among units (a watt is volts*amps, a yard is three …

The SL5 procedure mechanism

This paper describes an integrated procedure mechanism that permits procedures to be used as recursive functions or as coroutines. This integration is accomplished by treating procedures and their activation records (called environments) …

An interference matching technique for inducing abstractions

A method for inducing knowledge by abstraction from a sequence of training examples is described. The proposed method, interference matching, induces abstractions by finding relational properties common to two or more exemplars …

New sufficient optimality conditions for integer programming and their application

The purpose of this report is to present a new class of sufficient optimality conditions for pure and mixed integer programming problems. Some of the sets of sufficient conditions presented can be thought of as generalizations …

Computer generation of gamma random variables

A new method for generating random variables from the gamma distribution with nonintegral shape parameter &agr; is proposed. This method is similar to two other methods recently given by Wallace and Fishman. It is compared with Fishman's …

Optimal shift strategy for a block-transfer CCD memory

For the purposes of this paper, a block-transfer CCD memory is composed of serial shift registers whose shift rate can vary, but which have a definite minimum shift rate (the refresh rate) and a definite maximum shift rate. The …

ACM forum: on ACM and scientific freedom