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Communications of the ACM

Table of Contents


On the feasibility of voice input to an on-line computer processing system

An on-line digital computer processing system is considered in which an ordinary telephone is the complete terminal device, input to the computer being provided as a sequence of spoken words, and output to the user being audio …

On the conversion of decision tables to computer programs

The use of execution time diagnostics in pinpointing ambiguities in decision tables is discussed. It is pointed out that any attempt at resolving ambiguities at compile time will, in general, be impossible. It is shown that,  …

Scheduling to reduce conflict in meetings

Conflicts in scheduling can be treated as defining an undirected linear graph independently of the relation of the activities in conflict to additional constraints of time and space. Each connected component of such a graph,  …

A PL/1 program to assist the comparative linguist

A practical PL/1 program is described which can assist comparative linguists to determine the regular sound correspondences between genetically related languages. The investigator must arrange data for input by aligning pairs …

Automatic parsing for content analysis

Although automatic syntactic and semantic analysis is not yet possible for all of an unrestricted natural language text, some applications, of which content analysis is one, do not have such a stringent coverage requirement.  …

Accurate floating-point summation

This paper describes an alternate method for summing a set of floating-point numbers. Comparison of the error bound for this method with that of the standard summation method shows that it is considerably less sensitive to propagation …

Comparison of several adaptive Newton-Cotes quadrature routines in evaluating definite integrals with peaked integrands

This report compares the performance of five different adaptive quadrature schemes, based on Newton-Cotes (2N + 1) point rules (N = 1, 2, 3, 4, 5), in approximating the set of definite integrals ∫1-1 (x2 + p2)-1 dx with relative …

Incorporating origin shifts into the QR algorithm for symmetric tridiagonal matrices

The QR iteration for the eigenvalues of a symmetric tridiagonal matrix can be accelerated by incorporating a sequence of origin shifts. The origin shift may be either subtracted directly from the diagonal elements of the matrix …

Algorithm 383: permutations of a set with repetitions [G6]


Algorithm 382: combinations of M out of N objects [G6]


Algorithm 384: eigenvalues and eigenvectors of a real symmetric matrix


Certification of algorithm 245 [M1]:treesort 3:proof of algorithms—a new kind of certification


Remark on algorithm 201 [M1]: shellsort


Remark on algorithm 351 [D1]: modified Romberg quadrature


Remark on algorithm 361 [G6]: permanent function of a square matrix I and II


A relational model of data for large shared data banks

Future users of large data banks must be protected from having to know how the data is organized in the machine (the internal representation). A prompting service which supplies such information is not a satisfactory solution …