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REMORA


In 1988 Colette Rolland’s paper „An Information System Methodology supported by an Expert Design Tool“ is published. In this paper the REMORA methodology and an expert design tool, that supports the design of information systems, are described.

The REMORA methodology provides a consistent set of models, languages, methods and software tools to design and implement large and semantically complex information systems. As result of REMORA, especially the conceptual model’s use, there is a more direct and efficient interaction between the users and the designers. The conceptual model allows the definition of the information system conceptual schema.

An information system can be characterized as a collection of objects having structural (static) and behavioural (dynamic) relationships with each other and with the environment. The structure refers to states and static properties such as entities and their relationships. The behaviour refers to state transitions and dynamic properties like operations and events on entities and their relationships. REMORA interconnects static and dynamic properties to design large and complex information systems. So REMORA considers both a static and dynamic point of view.

The information system conceptual schema is a complete, consistent, not redundant and economic representation of the real world system structure and behaviour.

The conceptual model

REMORA tries to describe the real world system behaviour in a causal way. This means that events trigger operations that modify the state of objects.



Figure 1. Causal approach of behaviour modelling

 

The conceptual model includes three concepts called C-Objects, C-Operations and C-Events.

The C-Object concept represents a time consistent aspect of the real-world object or relationship.

The C-Operation concept allows the representation of elementary operation classes. Elementary operations are operations that produce an elementary state change of the IS. For example the creation or modification of a C-Object. 

The C-Event is an elementary state change type of only one C-Object that triggers one or more C-Operations.

Conceptual schema

The conceptual schema is a collection of C-Objects, C-Operations, C-Events and constraints. The schema integrates the modeling of data (C-Objects), their transformation (C-Operations) and the triggering conditions of these transformations (C-Events).



Figure 2. A graphical representation of the conceptual schema and conceptual schema elements

The two conclusions of REMORA

  • The design of complex and large information systems should be supported by tools. Software tools are necessary to integrate different views, to check their consistency and completeness, to produce documentation and to get the status of the design process. In their opinion an expert system is the best tool to handle the design process.
  • There are two different types of knowledge: knowledge about the real-world system and the knowledge to perform design activities. The two types of knowledge are shared by actors of the real world and design specialists. An expert system is able to bridge these classes of persons.

Expert System

An expert system is developed in the context of the REMORA methodology. From a real-world description, given in a subset of the natural language, the system generates the corresponding REMORA conceptual schema. The design is interactively done with the end user. 

The acquisition of knowledge happens through natural language recognition. An expert system (OICSI) picks up the application domain knowledge from natural language statements. There are different problems such as the richness of the natural language. So the use of the language is restricted.

The goal of an expert system is to get sufficient knowledge of the application domain and then to produce progressively, by interaction with the designer, the conceptual and logical schema according to the REMORA methodology. 

More information

Short biography

 

Reference

Rolland, Colette: An Information System Methodology supported by an Expert Design Tool, University of Paris, 1988, Elsevier Science Publishers