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Research and Advances

Directed random generation of sentences

The problem of producing sentences of a transformational grammar by using a random generator to create phrase structure trees for input to the lexical insertion and transformational phases is discussed. A purely random generator will produce base trees which will be blocked by the transformations, and which are frequently too long to be of practical interest. A solution is offered in the form of a computer program which allows the user to constrain and direct the generation by the simple but powerful device of restricted subtrees. The program is a directed random generator which accepts as input a subtree with restrictions and produces around it a tree which satisfies the restrictions and is ready for the next phase of the grammar. The underlying linguistic model is that of Noam Chomsky, as presented in Aspects of the Theory of Syntax. The program is written in FORTRAN IV for the IBM 360/67 and is part of a unified computer system for transformational grammar. It is currently being used with several partial grammars of English.
Research and Advances

Object code optimization

Methods of analyzing the control flow and data flow of programs during compilation are applied to transforming the program to improve object time efficiency. Dominance relationships, indicating which statements are necessarily executed before others, are used to do global common expression elimination and loop identification. Implementation of these and other optimizations in OS/360 FORTRAN H are described.
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Research and Advances

The role of programming in a Ph.D. computer science program

In this general paper the role of programming in advanced graduate training is discussed. Subject matter related to programming as well as programming per se is considered. The importance and application of formalism are considered and also the need for good empirical experimentation. A brief outline for a sequence of courses is included, and subject headings that have been obtained from an extensive bibliography are given. A bibliography of programming references is included.
Research and Advances

A system organization for resource allocation

This paper introduces a system for resource management using the concepts of “process,” “facility,” and “event.” Except for the processor no attempt has been made to give serious suggestions for the policy to be followed for resource allocation. However, a basic framework is provided in which a system analyst can express solutions to resource management problems. The paper is divided into a tutorial presentation, a description of the system primitives, and a small collection of examples of the use of the primitives.
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Research and Advances

A SIMSCRIPT-FORTRAN case study

Two programs for a vehicle dispatching model, one written in 7040 SIMSCRIPT and the other in 7040 FORTRAN IV are compared. The comparison is made in terms of basic program design decisions, storage requirements, computer time used, and the ease of making changes. In the SIMSCRIPT program, the primary design considerations center around the choice of model variables, model changing events, and model testing. In the FORTRAN program, basic design problems relate to the representation of the passage of time, the allocation of storage, and the organization of input data. The comparison of these differently designed programs shows that the SIMSCRIPT program uses more computer storage and more computer time, but requires fewer program changes to introduce model revisions.
Research and Advances

A multiprogramming environment for online data acquistion and analysis

An experimental system for acquisition and analysis of large bodies of data derived from scientific experiments is described. Its architecture and implementation is largely based on certain objectives and characteristics of a general data analysis scheme. Early applications have been oriented towards the investigation of data obtained in biological research. Some of the problems encountered by the chosen approach are discussed.
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Research and Advances

Algorithms for finding a fundamental set of cycles for an undirected linear graph

Given the adjacency matrix of the graph, the algorithm presented in this paper finds a spanning tree and then constructs the set of fundamental cycles. Our algorithm is slower than an algorithm presented by Welch by a ratio of N/3 (N is the number of nodes) but requires less storage. For graphs with a large number of nodes and edges, when storage is limited our algorithm is superior to Welch's; however, when the graphs are small, or machine storage is very large, Welch's algorithm is superior. Timing estimates and storage requirements for both methods are presented.
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Research and Advances

An online editor

An online, interactive system for text editing is described in detail, with remarks on the theoretical and experimental justification for its form. Emphasis throughout the system is on providing maximum convenience and power for the user. Notable features are its ability to handle any piece of text, the content-searching facility, and the character-by-character editing operations. The editor can be programmed to a limited extent.
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Research and Advances

The LACONIQ monitor: time sharing for online dialogues

The LACONIQ (Laboratory Computer Online Inquiry) Monitor was developed primarily to support non-numerical applications such as retrieval from very large files by means of a “dialogue” between a system user and a retrieval application. The monitor was designed so that it could work with a small computer (an IBM System 360/30). Therefore techniques for resource allocation were important. For this reason the use of core storage, computational facilities, and input-output were all scheduled. An unusual feature of the system is that it is event-driven rather than clock-driven. The program segments called into execution by the remote CRT consoles are invariably run to completion rather than “rolled-out” to be brought back at a later time.
Research and Advances

On the expected gain from adjusting matched term retrieval systems

A file adjustment procedure based on maximizing the Bayes expected gain is proposed for matched term retrieval systems. The expected gain and its probability distribution are derived as a function of: (1) the prior proportion of omitted terms, and (2) the coefficient of separation between two distributions corresponding to values of an adjustment statistic. An example evaluates the gain parameters for a typical information retrieval system.
Research and Advances

GEORGE 3—A general purpose time sharing and operating system

An Operating System is described which will run on a wide variety of configurations of the I.C.T. 1900, and can handle a large number of online console users while at the same time running several offline (background) jobs. The system is not oriented towards either mode and can be either a batch processing system (such as the ATLAS Supervisor, IBSYS, or GECOS), or a multiaccess system (resembling, to the user, CTSS or MULTICS), or both simultaneously, depending on the installation, which can adjust the Schedulers. Both online users and offline jobs use a common Command Language. The system includes a Multilevel device-independent File Store.
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Research and Advances

An experimental model of system/360

The problem of predicting the performance of modern computer systems is formidable. One general technique which can ease this problem is macroscopic simulation. This paper reports on the applicability of that technique to System/360. The paper describes an experimental model of System/360—its hardware, software, and its environment. The measures of system performance produced by the model consist of statistics relating to turnaround time, throughput, hardware utilization, software utilization, and queueing processes. The model is mechanized in SIMSCRIPT and consists of some 1750 statements. An auxiliary program, the Job Generator, creates automatically the properties of System/360 jobs that get simulated.
Research and Advances

Automatic data compression

The “information explosion” noted in recent years makes it essential that storage requirements for all information be kept to a minimum. A fully automatic and rapid three-part compressor which can be used with “any” body of information to greatly reduce slow external storage requirements and to increase the rate of information transmission through a computer is described in this paper. The system will also automatically decode the compressed information on an item-by-item basis when it is required. The three component compressors, which can be used separately to accomplish their specific tasks, are discussed: NUPAK for the automatic compression of numerical data, ANPAK for the automatic compression of “any” information, and IOPAK for further compression of information to be stored on tape or cards.
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Research and Advances

Methods for analyzing data from computer simulation experiments

This paper addresses itself to the problem of analyzing data generated by computer simulations of economic systems. We first turn to a hypothetical firm, whose operation is represented by a single-channel, multistation queueing model. The firm seeks to maximize total expected profit for the coming period by selecting one of five operating plans, where each plan incorporates a certain marketing strategy, an allocation of productive inputs, and a total cost. The results of the simulated activity under each plan are subjected to an F-test, two multiple comparison methods, and a multiple ranking method. We illustrate, compare, and evaluate these techniques. The paper adopts the position that the particular technique of analysis (possibly not any one of the above) chosen by the experimenter should be an expression of his experimental objective: The F-test tests the homogeneity of the plans; multiple comparison methods quantify their differences; and multiple ranking methods directly identify the one best plan or best plans.
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