# TAIS

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

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 PT
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 RT
31. Boundary Operator for Generalized Systems
2. Information Systems Theory
1. Information Systems
2. The Function of an Information System
3. The Economic Quantity of Information and Processing
4. Some Problems of Information Systems Design
5. Precedence Relations between Information Sets in and Information System
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

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.

## Import

TAIS is significant for several 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.

## Role in ai-integration.biz

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