TAIS

Wiki Article on Langefors

Theoretical Analysis of Information Systems¹ is a published approach to mathematical modeling of a general enterprise information system based on systems theory and algebra. Its results are basic and startling only to the degree in which something like what the book does has not become an element of common IS practice.

Studentenliiteratur

The TOC as reproduced below does not capture the incidence string style of the Auerbach original text, for example "Boundary Operator for Generalized Systems" the is marked § "12.31".

1. Systems Theory
   1. Basic Problems of Systems Theory
      1. Needs for a Formal Systems Theory
      2. Common Faults in Systems Design Analysis
      3. Different Kinds of Systems Study
      4. Systems Engineering
      5. Structural Systems Theory, Electric Networks and Elastic Systems
      6. Mathematical Systems Theory as a System
      7. Other Kinds of System Study
      8. Elements of a Systems Theory
      9. Usefulness of our Concise Definition of Systems
      10. The Systems Analysis Approach
      11. The Fundamental Principle of Systems Work
      12. General and Special Properties of System Problems
      13. Systems, Subsystems, Parts, and Boundaries
      14. Structure Types of a System
      15. System Partitioning
      16. Systems Partitioning of Outer Boundary
      17. A Sketch of a Basic Theory of Systems Analysis
      18. The Suitable Number of Subsystems in a System
   2. Systems Algebra
      1. Algebraic Tools for Describing Systems
      2. Precedemce Operator of a System (or Graph)
      3. The Precdence Matrix of a System
      4. The Precendents of s set of Parts
      5. Use of the Precedence Matrix P to Determine the Precedents of a Set of parts
      6. Connections with a Linked Data Structure
      7. Matrix by Matrix Composition pⁿ, n-th Precedents and Paths
      8. Succedence Matrix P_T
      9. Generalization of the Precendence Concept
      10. A generalized Matrix by Vector Operation
      11. Generalized Matrices
      12. Matrix Operations as Processing of Data Structures
      13. Other Kinds of Algorithms for Processing Data Structures
      14. P¹¹, the 1-dimensional Precendence Matrix
      15. P⁰¹ and P¹⁰, Precendence Matrices for Mixed 0-1 and 1-0 Dimension Respectively
      16. Relations between P⁰¹, P¹⁰, P¹¹, and P⁰⁰ Respectively
      17. Definition of E¹⁰, the Incidence Matrix
      18. Boundary Operations on a System and the Incidence Matrix
      19. Co-boundary Operation and Incidence Matrix
      20. The Coincidence Matrix M¹⁰
      21. Data Structure Representations of Incidence and Coincidence Matrices
      22. Illustrations of Boundary Operations in Accounting
      23. Built-up Systems and Gross Systems
      24. System Connections, Boundary Operation and Cycles
      25. Positional Operator for the System Graph
      26. Simple Paths and Closed Paths in a System Graph
      27. Transposed Positional Operator, Forward Positioning
      28. General Positioning
      29. Requirements Computation and Scheduling
      30. Determining the Boundary Operator from M¹⁰ and the Part Boundary Operator R^T
      31. Boundary Operator for Generalized Systems
2. Information Systems Theory
   1. Information Systems
      1. Information Systems Design
      2. Formalization of Information Systems Design
      3. Component Problems of Information Systems
   2. The Function of an Information System
      1. The Function of an Information System
      2. Two Tasks of an Information System
      3. Operative Information Requirments. An Example.
      4. The value of Directive Information
      5. Effect of time for Decomposing. Executive Decisions.
      6. Transient Decision Situation. Satisficing.
      7. Information Needed in a Simplified Model of a Manufacturing Shop
   3. The Economic Quantity of Information and Processing
      1. The Economic Quantity of Information and Processing
      2. Information Value as an Information Systems Design Parameter
      3. Information and System Control
      4. The Meaning of Information within a System
      5. The Value of Information in a System
      6. Data Representation aof Information in a System. Volume of Data
      7. The Information System for a Simple Inventory
      8. Operative vs. Directive Information
      9. An Example of Optimum Reduction. Information Processing for a Simple Inventory
      10. Information System for a Simple Work Station
   4. Some Problems of Information Systems Design
      1. Complexity of an Information System
   5. Precedence Relations between Information Sets in and Information System
      1. Data Structure of an Information System
      2. On the Definition of Elementary Files (e-files)
      3. Inference Problem in Information Systems Design
   6. Data and Information Files
   7. Files, Computations, and Processes
   8. Effect of a Process Grouping
   9. File Consolidation
   10. System Design Computation Using Matrix Algebra
   11. File Storage Considerations
   12. File Organizations
   13. System Reliability
3. Some Data Processing Problems
   1. Relation between a Process and its Files
   2. Influence of Word Structure

This TOC, as reproduced here, is the normative designation by which I reference the text of the original document, not the original section numbering. A small number of copies of the work appear to be available online.

Import

TAIS is significant for several obvious reasons. One is historical. The work was published shortly after the introduction of the concept of Software Engineering and before the emergence of OOP, Design Patterns, and other currents which came to represent the mainstream of of systems analysis and design practice.

The approach was developed over some time before the mid-1970s and so reflects a relatively low-level focus that seems quaint in a modern context. However the material culminating in the chapter on System Design Computation is of enduring value. I believe Langefors died a few years before the turn of the century and there was both a final work by him, related work by colleagues in Regnecentralen and other organizations, and related work from unrelated sources.

Role in ai-integration.biz

TAIS is the theoretical foundation of the general approach to information systems development in ai-integration.biz.

Further Reading

¹ Lagefors, B. Fourth Edition, AUERBACH. 1973 ISBN 0-87769-151-7