Jukka Parviainen

Using Self-organizing Map in a Computerized Decision Support System

Modern computerized decision support systems have developed to their current status during many decades. The variety of methodologies and application areas has increased during this development. In this paper neural method Self-Organizing Map (SOM) is combined with knowledge-based methodologies in a rule-based decision support system prototype. This system, which may be applied for instance in fault diagnosis, is based on an earlier study including compatibility analysis. A Matlab-based tool can be used for example in fault detection and identification. We show with an example how SOM analysis can help decision making in a computerized decision support system. An error state model made in Simulink programming environment is used to produce data for the analysis. Quantisation error between normal data and error data is one significant tool in the analysis. This kind of decision making is necessary for instance in state monitoring in control room of a safety critical process in industry.

SOM Based Decision Support in Failure Management

Computerized decision support system field covers many methodologies and application areas. In this paper self- organizing map (SOM) and knowledge-based techniques are used in combination to reason problematic situations in failure management. A process model that consists of individual connected process components has been developed. A primary circuit of a boiling water nuclear power plant including two branches has been composed. A failure management scenario is thoroughly analyzed and solved with the SOM based decision support system. The structure and reasoning of the computerized decision support system (CDSS) is also shortly discussed. The process model is demonstrated together with the CDSS and shown to be useful. The tool helps operators decision making with various visualizations, and by giving concrete recommendations for possible control actions or other acts.

Process state and progress visualization using self-organizing map

The self-organizing map (SOM) [1] is used in data analysis for resolving and visualizing nonlinear relationships in complex data. This paper presents an application of the SOM for depicting state and progress of a real-time process. A self-organizing map is used as a visual regression model for estimating the state configuration and progress of an observation in process data. The proposed technique is used for examining full-scope nuclear power plant simulator data. One aim is to depict only the most relevant information of the process so that interpretating process behaviour would become easier for plant operators. In our experiments, the method was able to detect a leakage situation in an early stage and it was possible to observe how the system changed its state as time went on.