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A Historical Perspective on Conceptual Modelling

(Based on an article and presentation by Janis Bubenko jr.,

Royal Institute of Technology, Sweden.

June 2005)

Pensum:

A01: Janis A. Bubenko jr: From Information Algebra to Enterprise Modelling and Ontologies – a Historical Perspective on Modelling for Information Systems in Conceptual Modelling in Information

Systems Engineering. Krogstie, John; Opdahl, Andreas Lothe; Brinkkemper, Sjaak (Eds.)

TDT4252, Spring 2013Lecture 1: Introduction

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Conceptual Modelling

• Definition:– represents 'concepts' (entities) and relationships between them.

• May be used for enterprise models, problem analysis requirements and design specification.

• Primarily diagrammatic (2-dimensional diagrams). • The languages used for modeling have a limited vocabulary.• The languages used are originally meant to be generally applicable

(and not for a specific domain). Some exception e.g. using so-called domain specific modeling techniques.

TDT4252, Spring 2013Lecture 1: Introduction

PERSON PAPERW RITES

LANGUAGE

TITLE

N M

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Focus of early attemps

• What were modelled were data and operations on the data.

• There was a focus on representing the domain in strict, formal, computer-independent terms.

• Data were modelled using abstract concepts.

TDT4252, Spring 2013Lecture 1: Introduction

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Modelling during four+ decades

TDT4252, Spring 2013Lecture 1: Introduction

Pioneering work concepts

Refinement, models and extensions

The search for a common framework

Participation and understanding

-Extended scope- Standardisation efforts

60s

70s

80s

90s

2005

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Modelling during four+ decades

TDT4252, Spring 2013Lecture 1: Introduction

Pioneering work concepts

Refinement, models and extensions

The search for a common framework

Participation and understanding

60s

70s

80s

90s

2005Database Models

-Extended scope- Standardisation efforts

Young & Kent, 1958,CODASYL, 1963,Langefors 1965

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Young and Kent (1958)“Abstract Formulation of Data Processing Problems”

TDT4252, Spring 2013Lecture 1: Introduction

•… a way of designing different alternative implementations

•Information set/item•Defining relationship•Producing relationship•Conditions•Temporal aspects

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CODASYL Development Committee:An Information Algebra (1962)

The goal of this work is to arrive at a proper structure for a machine-independent problem-defining language at the systems level of data processing.

… It should help the information processing community to clarify, understand the fundamental and essential features of data processing considerations.

…With current programming languages the problem definition is buried in the rigid structure of an algorithmic statement of the solution, and such a statement cannot readily be manipulated.

TDT4252, Spring 2013Lecture 1: Introduction

Source: CACM, Vol.5, No. 4, April 1962, pp. 190 - 204

CODASYL: Conference on Data System Languages

8 The Scandinavian School: Langefors

• the infological realm: where data processing problems were expressed.

• the datalogical realm: design and analysis of a information processing system.

• the “elementary message” – the smallest element that could certain any meaning.

TDT4252, Spring 2012Lecture 1: Introduction

e = <s, a, v, t>

s system point a attribute v value t time

e = <s, a, v, t>

s system point a attribute v value t time

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Modelling during four+ decades

TDT4252, Spring 2013Lecture 1: Introduction

Pioneering work concepts

Refinement, models and extensions

The search for a common framework

Participation and understanding

60s

70s

80s

90s

2005Database Models

-Extended scope- Standardisation efforts

ANSI/X3/SPARC,IFIP Working groups

Information System Models

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The period 1970-80 ”refinement and extensions"

• The 1975 ANSI/X3/SPARC (Standards Planning and Requirements Committee) report: the three schema approach– External– Conceptual– Internal

• IFIP WG 2.6 series: "Modelling in Database Management Systems” (1974)

• IFIP TC 8 on Information Systems (1976)

TDT4252, Spring 2013Lecture 1: Introduction

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ANSI/X3/SPARC, 1975

• The three-schema approach offers three types of schemas with schema techniques based on formal language descriptions:– External schema for user views

– Conceptual schema integrates external schemata

– Internal schema that defines physical storage structures

TDT4252, Spring 2013Lecture 1: Introduction

User view

Computer view

Neutral view

• The framework attempted to permit multiple data models to be used for external schemata.

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IFIP Working Groups

TDT4252, Spring 2013Lecture 1: Introduction

• IFIP: International Federation for Information Processing, an umbrella organisation for national societies working in the field of information technology.

• IFIP WG 2.6 series: "Modelling in Database Management Systems” (1974).

• IFIP TC 8 on Information Systems (1976).

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Significant issues, insights and proposals during the 70s

• An "object" and the "name of an object" are different things.

• Binary vs. Relational models.

• Specialisation and generalisation, inheritance.

• Distinction between types, sets, and instances.

• Constraints and deduction.

• The temporal dimension.

• Data Model Based Data Base Management Systems.

• Graphical query languages. In summary, most of the essential basic concepts of

modelling were invented and presented during the seventies.

TDT4252, Spring 2013Lecture 1: Introduction

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Modelling during four+ decades

TDT4252, Spring 2013Lecture 1: Introduction

Pioneering work concepts

Refinement, models and extensions

The search for a common framework

Participation and understanding

60s

70s

80s

90s

2005Database Models

-Extended scope- Standardisation efforts

Temporal aspects,Semantic Modelling

Information System Models

Business rule modelling

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Ambitions of the 80’s

• To understand better and improve parts of existing methods and tools.

• To harmonise different notions and methods.

• To enhance the requirements capture and validation stage of the

systems life-cycle.

• To provide computerised assistance to the process of developing a

specification.

• To pay attention to human, cognitive, linguistic and social aspects of

IS.

TDT4252, Spring 2013Lecture 1: Introduction

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Modelling research in the 80’s

• Improving the expressive power of semantic data models (including

abstraction mechanisms) and adding the temporal dimension.

• ”semantic modelling” vs relational data modelling.

• What are we modelling? The DB? The IS? The real world?

• The operational vs. the deductive and temporal approach.

TDT4252, Spring 2013Lecture 1: Introduction

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Modelling during four+ decades

TDT4252, Spring 2013Lecture 1: Introduction

Pioneering work concepts

Refinement, models and extensions

The search for a common framework

Participation and understanding

60s

70s

80s

90s

2005Database Models

Information System Models

Business rule modelling

Modelling of ”why”, Enterprise Models

-Extended scope- Standardisation efforts

User education and participation,User focus,Organisational change

18 Modelling in the 90’s: focus on organisational aspects, participation, and understanding

Why are we modelling?How are we modelling?

… "the understanding and support of i) Human activities at all levels in an organisation.ii) Change, be it of the product, of the process or of the

organisation.iii)Complex user organisations, and individual users"

(ESPRIT 91)

TDT4252, Spring 2013Lecture 1: Introduction

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The 90’s: Widening the scope

• Interoperable systems• Semantic heterogeneity• Non-functional requirements• Business modelling/engineering• Modelling of intentions and actors• Participative modelling• ”Method knowledge”*• ”Patterns”

TDT4252, Spring 2013Lecture 1: Introduction

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Modelling during four+ decades

TDT4252, Spring 2013Lecture 1: Introduction

Pioneering work concepts

Refinement, models and extensions

The search for a common framework

Participation and understanding

60s

70s

80s

90s

2005Database Models

Information System Models

Business rule modelling

Modelling of ”why”, Enterprise Models

-Extended scope- Standardisation efforts

Domain specific ”ontological models” and languages

Formality vs. informal

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Temporal aspects,Semantic Modelling

Modelling during four+ decades

TDT4252, Spring 2013Lecture 1: Introduction

Pioneering work concepts

Refinement, models and extensions

The search for a common framework

Participation and understanding

60s

70s

80s

90s

2005Database Models

Information System Models

Business rule modelling

Modelling of ”why”, Enterprise Models

-Extended scope- Standardisation efforts

User education and participation

Domain specific ”ontological models” and languages

Formality vs. informal

Young & Kent, 1958,CODASYL, 1963,Langefors 1965

ANSI/X3/SPARC,IFIP Working groups

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What do you think is important to model today?

TDT4252, Spring 2013Lecture 1: Introduction

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Current Trends

• Enterprise Models

• Active Knowledge Models

• Context

• Model-Driven Development

• Modelling social aspects and Communities

• Semantics, Ontologies

• Interoperability and Standardisation

• Leveraging on developments in other fields, e.g.– AI – reasoning about knowledge, knowledge representation, uncertain

knowledge– Modelling work in other engineering fields

TDT4252, Spring 2013Lecture 1: Introduction

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• Starting from very simple well-bounded conceptual descriptions of information and database systems, modelling has evolved into less well-defined domains.

• Our needs for modelling and expectations of models have evolved.

• Stakeholder involvement.• Focus of dynamics, semantics, active models.

Systems that can evolve as our needs evolve.

TDT4252, Spring 2013Lecture 1: Introduction

Conclusions

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Enterprise Modelling

• The purpose of modelling is not only IS design.• Models not only address “what?”, but also “why?”.• Integrates conceptual and process models of the business

with objectives, actors, business rules and information system requirements.

• Provides traceability from information system solutions to business objectives.

• Improves the quality of modelling and the models by making it a “participatory” activity.

TDT4252, Spring 2013Lecture 1: Introduction

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Summary

• Introduction to the course and practical information

• Historical perspective of IS modelling over 4+ decades.

TDT4252, Spring 2013Lecture 1: Introduction

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TDT4252, Spring 2013Lecture 1: Introduction