November 1964 - Vol. 7 No. 11
Features
An inductive approach to language translation
The possibility of natural language translation by means of fixed operations on example translation is considered. The conception of sentence translation which motivates the work is informally presented, and the measurement of physical similarity in pairs of strings is discussed, a nation which plays a central role in the proposed type of translator. Experimental evidence is presented in support of the premise upon which this conception is based.
Rounding problems in commercial data processing
A common requirement in commercial data processing is that the sum of a set of numbers, rounded in a generally understood manner, be equal to the sum of the numbers rounded individually. Four rounding procedures are described to accomplish this. The particular procedure that is appropriate depends upon whether the numbers being accumulated can vary in sign, whether their sum can vary in sign, and whether the last number being summed can be recognized as such prior to its rounding.
Multiple-precision arithmetic and the exact calculation of the 3-j and 9-j symbols
Described in this paper is a system of general-purpose multiple-precision fixed-point routines and their use in subroutines which calculate exactly the quantum-mechanical 3-j, 6-j and 9-j symbols of large arguments.
The Vocabulary Subcommittee of the International Standards Organization's Technical Committee on Computers and Information Processing (ISO/TC97/SC1) held its third meeting in New York City in May, 1964. (More precisely, this was the subcommittee's first meeting. Its earlier meetings in Geneva and Paris were as a Working Group.) The program of work agreed upon at the New York meeting marks a sharp reversal of SC1's earlier plans.
A technique for reading gapless tapes makes electrocardiograph analysis feasible on the IBM 7090
To study arrhythmias and higher frequency components of the electrocardiogram, long series of patient heart cycles must be examined before valid comparison of different heart beats can be made. A technique is presented for the automatic analysis of long series heart cycles via a digital computer.
Estimation of heart parameters using skin potential measurements
A fundamental problem of vectorcardiography is the estimation of the state of the heart on the basis of skin potential measurements.
A mathematical model relating ventricular dipoles to surface potentials is sketched. Then it is shown that the inverse problem—that of determining electrical heart parameters on the basis of skin potential measurements—may be viewed as a nonlinear multipoint boundary value problem.
A feasible solution, employing quasilinearization and high-speed digital computers, is given.
An executive system implemented as a finite-state automaton
The 473L command and control system used by the Air Force permits many operators to access large data files through the use of a computer. The man-machine interface is satisfied by several communication consoles from which operators may enter queries and view replies. A data link permits remote stations to send messages, status reports and inventories directly to the computer. The information received over the online data link is used to update the data files which are stored on disk.
The 473L programming system is divided into an Executive Control Program and five components with different processing priorities. These priorities permit the system to be most sensitive to the console inputs and permit the operators at all the consoles to time share the central processor. The Executive Control Program provides for the orderly transitions of control among the programming system components. The major emphasis of the paper is on the technique of using the definition of a finite-state automaton for organizing the Executive Control Program.
Time sharing in a traffic control program
The Toronto traffic-signal control system consists of a variety of logically distinct computer programs, all competing for machine time. To satisfy these demands, a time-sharing program has been written whose purpose is to execute, in the order of a predefined priority, the various subprograms within the real-time system. In this paper the more interesting aspects of the time-sharing program are outlined.
