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Communications of the ACM

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President's letter

From Washington

ACM forum

Programmimg pearls

Special section on architectures for knowledge-based systems

A fundamental shift in the preferred approach to building applied artificial intelligence (AI) systems has taken place since the late 1960s. Previous work focused on the construction of general-purpose intelligent systems; the …

The role of frame-based representation in reasoning

A frame-based representation facility contributes to a knowledge system's ability to reason and can assist the system designer in determining strategies for controlling the system's reasoning.

Rule-based systems

Rule-based systems automate problem-solving know-how, provide a means for capturing and refining human expertise, and are proving to be commercially viable.

Logic programming

Logic programming is programming by description. The programmer describes the application area and lets the program choose specific operations. Logic programs are easier to create and enable machines to explain their results  …

Concepts of the text editor Lara

Lara, a text editor developed for the Lilith workstation, exemplifies the principles underlying modern text-editor design: a high degree of interactivity, an internal data structure that mirrors currently displayed text, and  …

Extended use of null productions in LR(1) parser applications

Applications programmed using LR(1) parsers should be designed so that as many functions as possible are controlled by the driving parsing machine through conveniently staged reductions and associated primitive actions; in this …

Data structures for quadtree approximation and compression

A number of data structures for representing images by quadtrees without pointers are discussed. The image is treated as a collection of leaf nodes. Each leaf node is represented by use of a locational code corresponding to a …

An expert system for a resource allocation problem

We describe an expert system for resource allocation in a particular military domain. The system incorporates variants of several important techniques of artificial intelligence and makes the first use of the Merit system for …