Evaluation of a Text Compression Algorithm against Computer-Aided Instruction (CAI) Material

Abstract

INFORMATION STRUCTURED CAI material. The resulting compression ratios are near 1.5 to one for both types of materials. The simulation program was modified to apply the algorithm to the lesson files of a particular frame- structured CAI subsystem used in the Air Force Phase II Base Level System. The compression in this case was found to be 1.3 to one because of the presence in the lesson file of uncompressible, frame formatting bytes. The modified simulation program was also used to take letter occurrence statistics on the text being compressed. From these, a theoretical compression was calculated using a probabilistic model of the compression algorithm. Theoretical compression was within two per cent of measured compression, thus verifying the model's applicability.

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Document Details

Document Type
Technical Report
Publication Date
Jul 01, 1972
Accession Number
AD0759162

Entities

People

  • Joseph M. Knight Jr.

Tags

Communities of Interest

  • C4I

DTIC Thesaurus Topics

  • Air Force
  • Compression
  • Computer Programming
  • Computer Programs
  • Computer-Aided Instruction
  • Computers
  • Data Compression
  • Databases
  • Dictionaries
  • Information Systems
  • Instructions
  • Language
  • Materials
  • Models
  • Probabilistic Models
  • Probability
  • Training

Readers

  • Database Systems and Applications
  • Mechanical Engineering/Mechanics of Materials.