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Communications of the ACM

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Computer perspectives: the bandwidth famine

A number of years ago I visited a young and successful computer company and was given a tour of the facilities by one of the directors. We passed offices in which people were working at computer terminals; I was told they constituted …

Legally speaking: should program algorithms be patented

In the Legally Speaking column last May [6], we reported on a survey conducted at last year's ACM-sponsored Conference on Computer-Human Interaction in Austin, Tex. Among the issues about which the survey inquired was whether …

Cyc: toward programs with common sense

Cyc is a bold attempt to assemble a massive knowledge base (on the order of 108 axioms) spanning human consensus knowledge. This article examines the need for such an undertaking and reviews the authos' efforts over the past …

Knowledge and natural language processing

KBNL is a knowledge-based natural language processing system that is novel in several ways, including the clean separation it enforces between linguistic knowledge and world knowledge, and its use of knowledge to aid in lexical …

Natural language understanding and speech recognition

Natural language understanding must be an integral part of any automatic speech recognition system that attempts to deal with interactive problem solving. The methods for representing and integrating knowledge from different …

Highlights from the second annual computer bowl

Cache considerations for multiprocessor programmers

Although caches in most computers are invisible to programmers, they significantly affect program performance. This is particularly true for cache-coherent, shared-memory multiprocessors. This article presents recent research …

A bridging model for parallel computation

The success of the von Neumann model of sequential computation is attributable to the fact that it is an efficient bridge between software and hardware: high-level languages can be efficiently compiled on to this model; yet it …

Sharing scientific data

The willingness of one scientist to share data with another scientist continues to be influenced by a number of enconomic, social, psychological and political factors.

Physical design equivalencies in database conversion

As relational technology becomes increasingly accepted in commercial data processing, conversion of some of the huge number of existing navigational databases to relational databases is inevitable. It is thus important to understand …

A very fast substring search algorithm

This article describes a substring search algorithm that is faster than the Boyer-Moore algorithm. This algorithm does not depend on scanning the pattern string in any particular order. Three variations of the algorithm are given …

Inside risks: insecurity about security?

Background A few highly visible cases of computer system exploitations have raised general awareness of existing vulnerabilities and the considerable risks they entail.