A little more than a decade ago my colleagues and I faced the necessity for providing a database management system which might commonly serve a number of different types of computer aided design applications at different manufacturing enterprises. We evaluated some wellknown cases of conceptual models and commercially available DBMSs, and found none fuHy meeting the requirements. Yet the analysis of them led us to the development of what we named the Logical Structure Management System (LMS). Syntactically the LMS language is somewhat similar to ALPHA by E. F. Codd. The underly- ing conceptual model is entirely different from that of the relational model, however. LMS has been since put into practical use, meanwhile a further ef- fort in search of asound theoretical base and a concrete linguistic framework for true product modeling together with comparative studies of various ap- proaches has been made. Here, the term product modeling is used to signify the construction of informational models of design objects and design pro- cesses in which it must be possible to include not a fixed set of attributes and relations, such as geometry, physical properties, part-of hierarchy, etc. , but whatever aspects of design designers may desire to be included. The purpose of this book is to present the major results of the said effort, which are primarily of a theoretical or conceptual nature. Following the intro- duction (Chap.

Table of Contents:
0 Introduction.- 0.1 Primary Organization of a CAD System.- 0.2 Current State of Integration and Distribution.- 0.3 Roles of a Database.- 0.4 Toward Product Modeling.- 0.5 The Subject Matter.- 0.6 An Example.- 0.7 On the Formalness and Abstractness of Language.- 0.8 On the General Theory of Design.- 0.9 Program for Succeeding Chapters.- References.- 1 Requirements of CAD Databases.- 1.1 Structures and Semantics.- 1.2 Dynamic Aspect.- 1.3 Version Control.- References.- 2 Criticism of Past and Current Data Models.- 2.1 Graphics Packages in the 1960s.- 2.1.1 Ring Structure, Typically ASP.- 2.1.2 LEAP, an Associative Language.- 2.1.3 Set-theoretic Data Structure (STDS).- 2.2 Ad hoc Developments of CAD Databases.- 2.3 The Network (CODASYL) Model and Its Extensions.- 2.3.1 Structure and Basic Functions.- 2.3.2 Criticism.- 2.4 Relational Model and Its Extensions.- 2.4.1 Structure and Basic Functions.- 2.4.2 Criticism.- 2.4.3 Semantic Extensions of Relational Model.- 2.4.4 Applications of the Relational Model to CAD.- References.- 3 First Order Theory and Its Interpretation.- 3.1 First Order Language.- 3.2 Formal Theory.- 3.3 Interpretation of First Order Theory.- 3.3.1 Fundamental Concepts and the Completeness of FOPL.- 3.3.2 Morphism between Interpretations.- 3.4 Undecidability and Incompleteness.- 3.5 Clausal Form and the Herbrand Model.- References.- 4 Criticism of Logical Approaches.- 4.1 Pertinencies of Logic to Computer Sciences and Applications.- 4.2 Theory or Interpretation?.- 4.2.1 Information Systems as Formal Theories.- 4.2.1.1 General Discussion.- 4.2.1.2 Logic Programming (LP).- 4.2.1.3 Abstract Data Typing (ADT).- 4.2.2 Criticism.- 4.3 Meanings of Logical Formulas.- 4.3.1 Deductive Data Modeling.- 4.3.2 Derivation Rules, Integrity Constraints or What?.- 4.4 Single or Multiple Interpretations?.- 4.5 The Universe of Interpretation.- 4.6 What Kind of Logic?.- 4.6.1 Semantic Network (SN).- 4.6.2 Criticism.- 4.6.3 Network Represented as a Logical Structure.- 4.6.4 Limitations of FOPL.- References.- 5 Philosophical Discussions.- 5.1 Philosophical Reinterpretations of Conceptual Frameworks.- 5.1.1 Entity-Centered and Subject-Predicate Weltanschauung.- 5.1.2 Intensions and Extensions.- 5.2 Criticism of Underlying Weltanschauungen.- 5.3 An Alternate Weltanschuung.- 5.3.1 Characteristics of Our Universe of Discourse.- 5.3.2 The Paradigms: A Methodological Basis.- References.- 6 The Fundamental Structure of the Design Object Model.- 6.1 Physical Object, Theory and Interpretation.- 6.2 Qualifications on Theories and Interpretations.- 6.3 Illustrative Examples.- References.- 7 The Model Description Language (MDL).- 7.1 General.- 7.2 Theory Construction.- 7.2.1 Declarations and Definitions.- 7.2.2 Procedural Statements.- 7.3 Interpretation.- 7.3.1 Declarations and Definitions.- 7.3.2 Procedural Statements.- 7.4 Illustrative Examples.- References.- 8 Modeling the Design Process.- 8.1 The Concept of Minimal Extension.- 8.1.1 General.- 8.1.2 Fundamental Procedure.- 8.2 The Expansion of Model Description Language (MDL).- 8.2.1 Syntax and Semantics.- 8.2.2 Illustrative Examples.- 8.3 Controlling the Model Development.- 8.3.1 Working Principles for Programming Processes.- 8.3.2 System Facilities at the Macroscopic and Intelligent Level.- References.- 9 Implementation and Remaining Problems.- 9.1 General Organization.- 9.1.1 Structure of a Model.- 9.1.2 Structure of the Data Storage.- 9.2 Logical Structure Description Language (LDL).- 9.3 Logical Structure Manipulation Language (LML).- 9.4 Logical Structure Manipulation Utility (LMU).- 9.5 Examples and Applications.- 9.5.1 Examples.- 9.5.2 Applications.- 9.6 Remaining Problems.- References.