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Communications of the ACM

Table of Contents


Letter from an ACM past president: Science policy and human rights


General considerations on the design of an interactive system for data analysis

Among the most important criteria in the design and implementation of an interactive system for data analysis are: data structure, control language, user interface, sytem versatility, extensibility, and portability. The design …

A generalized text editor

Text is not the only data that needs editing; for example, file deletion utilities edit directories. If all “editors” used the same command language, they would be easier to learn, remember, and code. This paper describes a generalized …

A linear algorithm for copying binary trees using bounded workspace

An algorithm to copy a binary tree in linear time using bounded workspace is presented. The algorithm does not modify the original tree at any time. The copy is constructed in such a way that it can be traversed in a read-only …

Region representation: quadtrees from boundary codes

An algorithm is presented for constructing a quadtree for a region given its boundary in the form of a chain code. Analysis of the algorithm reveals that its execution time is proportional to the product of the perimeter and  …

Region representation: boundary codes from quadtrees

There has been recent interest in the use of quadtrees to represent regions in an image. It thus becomes desirable to develop efficient methods of conversion between quadtrees and other types of region representations. This paper …

technical correspondence: on the representation of the simulation event set


Technical correspondence: on encoding of line numbers. author's response


Technical correspondence: on encoding of line numbers


Technical correspondence: on the representation of the simulation event set. author's response


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