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A previous paper presented an efficient algorithm, called the Recomputation Algorithm, for evaluating a rational expression to within any desired tolerance on a computer which performs variable-precision arithmetic operations. The Recomputation Algorithm can be applied to expressions involving any variable-precision operations having O(10-... + Σ ∣ε∣) error bounds, where p denotes the operation's precision and ε, denotes the error in the operation's with argument. This paper presents an efficient variable-precision exponential operation with an error bound of the above order. Other operations, such as log, sin, and cos, which have simple series expansions, can be handled similarly. [ABSTRACT FROM AUTHOR]

The article presents information on various chapters of the Association for Computing Machinery (ACM) across the U.S. The Greater Rio Grande Chapter of ACM has recently extracted from its files a list of the titles of all technical papers presented at Chapter meetings since its inception in 1957. Using a program developed by D.K. Robbins of Sandia Corp., a KWIC-type listing of permuted titles of these papers has been made. This listing has been distributed to all members of the Chapter. Topics and speakers at ACM Chapters across the U.S. indicate the current trends of interest in computer science and data processing. The ACM Tidewater Chapter is sponsoring this spring a professional development course on "Real-Time Computing." The course is given by the Chapter's professional development chairman, Cecil Frost, who is applications staff specialist for Control Data Corp. At its April 21, 1966 meeting, the Westchester-Fairfield Chapter heard William Orchard-Hays speak on "Linear Programming of Computational Techniques."

Various kinds of interference between communicating parallel processes have been examined by Dijkstra, Knuth and others. Solutions have been given for the mutual exclusion problem and associated subproblems, in the form of parallel programs, and informal proofs of correctness have been given for these solutions. In this paper a system of parallel processes is regarded as a machine which proceeds from one state S (i.e. a collection of pertinent data values and process configurations) to a next state 5' in accordance with a transition rule S ⇒ S . A set of such rules yields sequences of states, which dictate the system's behavior. The mutual exclusion problem and the associated subproblems are formulated as questions of inclusion between sets of states, or of the existence of certain sequences. A mechanical proof procedure is shown, which will either verify (prove the correctness of) or discredit (prove the incorrectness of) an attempted solution, with respect to any of the interference properties. It is shown how to calculate transition rules from the "partial rules" by which the individual processes operate. The formation of partial rules and the calculation of transition rules are both applicable to hardware processes as well as to software processes, and symmetry between processes is not required. [ABSTRACT FROM AUTHOR]

This paper presents an approach to writing specifications for parts of software systems. The main goal is to provide specifications sufficiently precise and complete that other pieces of software can be written to interact with the piece specified without additional information. The secondary goal is to include in the specification no more information than necessary to meet the first goal. The technique is illustrated by means of a variety of examples from a tutorial system. [ABSTRACT FROM AUTHOR]

The article reports on the correspondences of hollerith and 8-bit codes for computer environment. It solicits the comment that refers to the assignments of character(s) sets in the provided table as a basis for standardization. Hollerith is the name given to the 128-character, 12-row card code called USA Standard Hollerith Punched Card Code for Information Interchange. In relation, the USA Standard Code for Information Interchange's (USASCII) standard code assignment as well as other codes several correspondence tables are reflected.

The onward sweep of automatic processing of information is impeded by nine principal barriers: geography, cost, problem complexity, man-machine communication, inadequate sensors, lack of understanding, distance, time, and size. The main incentive for breaching these barriers is the universal need for processing information, ever more urgent of the greater port of human work activity changes from production to service. Computer developments in hardware, programming, timesharing, education, data communication, and displays are judged by how effectively they remove these barriers, and their barrier-smashing potentialities indicate continued rapid expansion. Problem-oriented languages are particularly effective over the entire front. Online computers and time-sharing also rate high by this measure. Education and increased understanding are basic to all progress with the computer. This complex but powerful tool is the most important one available to governments and scientists to use in studying the problems being created by the population explosion, and in analyzing possible solutions. [ABSTRACT FROM AUTHOR]

A method is described for implementing the productions of a context-free phrase structure grammar in a PL/l procedure whose structure and statements parallel the structure and notation of the grammar. [ABSTRACT FROM AUTHOR]