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Research and Advances Feb 1 1986

Dynamic initial allocation and local reallocation procedures for multiple stacks

Two new procedures for manipulating multiple stacks which share sequential memory locations are discussed. The first is the dynamic initial allocation procedure in which each stack is allocated as its first element arrives rather than having every stack preallocated at the very beginning of the entire process. The second is the local reallocation procedure; in this scheme, when a stack overflows, only its neighboring stacks, rather than the entire memory area, are reorganized provided that a certain condition is satisfied. The results of simulation appear to suggest that these new approaches improve the operational performance in many applications. With appropriate modifications, these concepts may also be applied to any other type of multiple linear lists (e.g., multiple queues) sharing sequential memory locations.
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Research and Advances Jan 1 1986

Structured tools and conditional logic: an empirical investigation

Prior research has identified two psychological processes that appear to be used by programmers when they perform design and coding tasks: (a) taxonomizing—identifying the conditions that evoke particular actions; and (b) sequencing—converting the taxa into a linear sequence of program code. Three structured tools—structured English, decision tables, and decision trees—were investigated in a laboratory experiment to determine how they facilitated these two processes. When taxonomizing had to be undertaken, structured English outperformed decision tables, and decision trees outperformed structured English. When sequencing had to be undertaken, decision trees and structured English outperformed decision tables, but decision trees and structured English evoked the same level of performance.
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Research and Advances Jan 1 1986

Understanding the effectiveness of computer graphics for decision support: a cumulative experimental approach

A total of 840 junior and senior-level undergraduate business students particpated in three experiments that compared computer-generated graphical forms of data presentation to traditional tabular reports. The first experiment compared tables and bar charts for their effects on readability, interpretation accuracy, and decision making. No differences in interpretation accuracy or decision quality were observed for the two groups, although tabular reports were rated as "easier to read and understand" than graphical reports. The second experiment compared line plots to tables for their effects on interpretation accuracy and decision quality. Subjects with graphical reports outperformed those with tables. There were no meaningful differences in interpretation accuracy across treatment groups. The third experiment compared graphical and tabular reports for their ability to convey a "message" to the reader. Only in situations in which a vast amount of information was presented and relatively simple impressions were to be made, did subjects given graphs outperform those using tables. This program of cumulative experiments indicates that generalized claims of superiority of graphic presentation are unsupported, at least for decision-related activities. In fact, the experiments suggest that the effectiveness of the data display format is largely a function of the characteristics of the task at hand, and that impressions gleaned from "one shot" studies of the effectiveness of the use of graphs may be nothing more than situationally dependent artifacts.
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Research and Advances Jan 1 1986

Data quality and due process in large interorganizational record systems

As societies have become more dependent on information systems to conduct and record transactions between organizations and individuals, interorganizational computer systems have become a widely used method of coordinating the actions of independent organizations. This article examines the quality of data in one important interorganizational system—the criminal-record system of the United States.
Research and Advances Jan 1 1986

Selected papers from the sixth international conference on information systems

There are a number of alternative tools and methods for building and designing information systems for organizational use. Each tool or design alternative has its advocates. Benefits and advantages are proposed or claimed; little empirical evidence is presented. The two selected papers from the 1985 International Conference on Information Systems (Indianapolis, December 15-18) present empirical laboratory experiments to provide evidence as to tools and design alternatives. The first paper by Dickson, DeSanctis, and McBride describes three experiments to compare traditional tabular presentation with graphic presentation. The experiments are designed to build cumulative research results around the issue of the task the reader of the information is to perform upon receiving the information. The second paper by Vessey and Weber provides experimental evidence comparing methods for documenting a problem: decision tree, decision table, and structured English. The three methods are frequently presented as alternatives; the experiments compare them. Two studies do not settle an issue as complex as comparison of alternative tools and methods: they begin to provide the evidence needed. They also illustrate one well-established research approach—the laboratory experiment. The advantage of laboratory experiments is the control that can be obtained; field studies and experience of practitioners can be understood more fully in the context of such laboratory results.
Research and Advances Dec 1 1985

Data compression on a database system

A general-purpose data-compression routine—implemented on the IMS database system—makes use of context to achieve better compression than Huffman's method applied character by character. It demonstrates that a wide variety of data can be compressed effectively using a single, fixed compression routine with almost no working storage.
Research and Advances Dec 1 1985

Selecting MIS projects by steering committee

Steering committees have recently gained vast acceptance in organizations as the mechanism used to select management information systems (MIS) projects. Because of their widespread adoption and their differences from other selection mechanisms with respect to orientation, steering committees were chosen for study. Data from 92 projects selected from 32 organizations were analyzed. As hypothesized, projects selected by steering committees were found to differ significantly from those chosen via other selection mechanisms. The implications of this result for organizations using steering committees to select MIS projects are presented.
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Research and Advances Dec 1 1985

Prolog in 10 figures

In the fall of 1981, a Japanese report officially initiated the quest for fifth-generation computers that would encompass the functions of knowledge processing and artificial intelligence. The conceptual underpinnings behind Prolog—Japan's language of choice for these activities—are presented here in a way that suggests why Prolog or a similar language might be considered a model for designing the computers of the future.

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