Mikito Iwamasa

Concept design visualization-a component-based approach

The paper presents a new framework and design methodology for concept-level systems design. The central part of the framework is an introduction of the components to represent the systems concept. The framework utilizes these components to navigate the designers exploration to obtain subsystems and semiautomatically integrates subsystems into one whole system. The design exploration (DE) components are a set of abstractions of the design exploration activities. A design history is recorded as a dependency graph of the DE components. The systems integration (SI) components are a set of relationships between subsystems from the systems integration perspective. Using SI components, the designer can design the systems hierarchical structure as a graph, the systems integration graph. By introducing a common semantic ground for these components, a design navigation algorithm and a conversion algorithm from the design history to the systems integration graph are introduced.

A pilot system for plant control using model-based reasoning

Conventional heuristic-based expert systems for diagnosis and control cannot adequately handle unforeseen abnormal events. Our system combines heuristics with model-based reasoning to control a thermal power plant, and to diagnose and resolve abnormal events at the plant. >

Model-based diagnosis using qualitative causal model and set-covering

A model-based diagnostic system is proposed for continuous physical devices such as a thermal power plant. The aim of model-based diagnosis is to find faulty components in the model from observations. Set-covering is an approach to diagnosis when the causal relations between symptoms and disorders are clearly defined. The new method combines the model-based approach and set-covering approach. The authors introduce the qualitative causal model (QCM) and define symptoms and qualitative disorders in QCM. The system has two submodules to calculate diagnosis from symptoms. The qualitative propagation module calculates the causal relations between the symptoms and the qualitative disorders. The BIPARTITE module based on set-covering generates all the diagnoses using these relations. The proposed method is proved to realize the diagnosis from first principles in the continuous physical domain.<<ETX>>