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Research and Advances

Transparent-mode control procedures for data communication, using the American standard code for information interchange—a tutorial

This paper gives the considerations of Task Group X3.3.4 in the area of transparent-mode data communication control philosophy. The appearance of this paper was forecast (under the name of “second-level control”) in the earlier tutorial paper, “Control Procedures for Data Communications,” Task Group document X3.3.4.44, dated May 1964. The present paper elaborates upon solutions to the problems of transparency to the basic ASCII communication control characters, as outlined in the previous paper mentioned above. Moreover, it goes on to cover the additional control problems of handling material such as offline encrypted data or non-ASCII codes by means of systems providing complete character transparency. It does not cover concepts of transparency in which the normal character structure or modulation rate of a system may be abandoned. In conjunction with the earlier tutorial paper, this paper is expected to lead to a proposal for standardization of data communication control procedures using the American Standard Code for Information Interchange.
Research and Advances

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.
Research and Advances

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.
Research and Advances

A rapid method for digital filtering

Since much of the computer time spent in time-series analysis is used for multiplications, a minimum multiplication method was devised for digital filtering, with the expectation that it would be useful in the online, real-time analysis of biological data. The filters are constructed from a succession of readily analyzable components in a manner that facilitates cascading. The repertoire of frequency response curves includes relatively good low-pass and band-pass designs. Programs are available for implementing both the synthesis of these filters, and their application on computers whose assemblers allow the definition of recursive macros.
Research and Advances

Machine controls for analysis of variance

A major problem in using the analysis of variance, as the number of factors increases, is the exponential rise in the number of interactions. Even though the experimenter may not be interested in these interactions it is impossible to ignore them in most experimental designs because of the problem of getting error terms. It is natural therefore to look to the computer to handle the bulk of work involved in computing the interactions. A program device to get the computer to do this is described.
Research and Advances

Final examination scheduling

A method for scheduling final examinations to yield a minimal number of student conflicts is described. The “minimization” is achieved by repetitively evaluating a nonlinear set of equations. Imbedded in the process is a random or Monte Carlo selection of assignments. As in such heuristic techniques, the solution may not be optimum and many solutions may be found which yield locally minimal results. Computer programs are described and empirical results given.
Research and Advances

An alternate checksum method

To increase reliability of transmission between magnetic tape and core storage on an IBM 7090/7094, blocks or records of data are often assigned a word called a logical checksum. This is a number derived from the block by some simple algorithm and as unique to it as possible. The method most commonly used to form a checksum is to add together every datum in the block by the ACL (add and carry logical) instruction.

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