Yuji Niwa

Enhancing Operator Control by Adaptive Alarm Presentation

The use of alarms in process control is a complex affair, because alarms can have many different functions over and above that of alerting the operator to a new event. Alarms are potentially a rich source of information that can be used in all phases of responding to a disturbance and should therefore be considered as an aspect of the general process information. From the point of view of cognitive systems engineering, alarms provide information that enables the operators to maintain control of the process and to be proactive as well as reactive. An important issue is the time and effort needed to evaluate events and new information (time to evaluate: TE) and the time and effort needed to select an appropriate response or line of action (time to select: TS). The former (TE) can be supported by more effective presentation of information, specifically a more comprehensive presentation of alarms. The latter (TS) can be supported by various kinds of computerized support, ranging from planning systems to adapt...

Discovering Admissible Simultaneous Equation Models from Observed Data

Conventional work on scientific discovery such as BACON derives empirical law equations from experimental data. In recent years, SDS introducing mathematical admissibility constraints has been proposed to discover first principle based law equations, and it has been further extended to discover law equations from passively observed data. Furthermore, SSF has been proposed to discover the structure of a simultaneous equation model representing an objective process through experiments. In this paper, SSF is extended to discover the structure of a simultaneous equation model from passively observed data, and is combined with the extended SDS to discover a quantitative simultaneous equation model reflecting the first principle.

The Design of Human-Machine Interface for Accident Support in Nuclear Power Plants

Abstract: As feedback from Three Mile Island No. 2, a large amount of human–machine interface (HMI) design has been proposed to support operators during accidents by presenting information on plant status, some of which is implemented in commercial nuclear power plants (NPPs). However, it has not yet been discussed what role HMI should play under conditions where operators must take action as instructed under emergency operating procedure. Regarding this principal issue, an HMI design is proposed together with specific screen images. The advantage of this design is based on the involvement of an ex-operator in NPP in this paper. The participation of users in the design of HMI has been rare. Accordingly the proposed HMI is comprehensive for average operators and is expected to be acceptable for future implementation in commercial NPPs. The effectiveness of the proposed HMI has been examined in a small experiment.

Autonomous Recovery Execution in Nuclear Power Plant by the Agent

Abstract: This paper has pointed out the necessity of careful decision making by nuclear power plant (NPP) operators based on the critical parameters of an NPP, to maintain safety when these parameters are out of range. Yet under strong time pressure, it is virtually impossible to make optimal decisions in these conditions. The automation of recovery actions may therefore be needed. Considering the requirements for such automation, the paper proposes an autonomous system in collaboration with the human (i.e., an agent system) that will remain effective even during unforeseen conditions. The numerical simulation study showed the effectiveness of the proposed system. The desired relationship between human–machine as the joint system based on a new concept was also proposed.

A proposal for a new accident analysis method and its application to a catastrophic railway accident in Japan

In a society of highly advanced technology, a new type of compound accident takes place. In an accident analysis, recent research concerns three aspects: human (M), technology (T) and organisation (O). However, technologies are developing day by day and it is becoming difficult to find causes of the recent compound accidents even with M, T and O analyses. This paper suggests further analyses considering the recent change of Western and Japanese societies quoting the recent catastrophic railway accident in Japan.

Principles of Performance Monitoring in Coupled Human-Machine Systems

Abstract The automatic monitoring of operator perfonnance can be used for several specific purposes such as guarding against forgetting or missing required actions, or ensuring that actions are not carried out in the wrong order. It is effectively an attempt to provide feedback to operators at an early state, i.e., before the effects of perfonnance deviations become obvious. Perfonnance monitoring can be based on the sequence or organisation of actions provided by procedures, and thereby become an extension of a computerised procedure system. Another possibility is to apply perfonnance monitoring independently of a computerised procedure system, although it must in some way refer to the infonnation provided by the procedures - or to equivalent infonnation that describes what should be done and how it should be done. This paper outlines the main functional requirements to perfonnance monitoring, within the context of a computerised procedure system.

Collaborative Emergency Operation of Man-Machine System in Nuclear Power Plant

Abstract In this paper, the scientific investigations and analyses pointed out the necessity of the careful decision-making of NPP operators considering the critical parameters of NPP to attain the safety and those causalities amongst these parameters. Under the strong time pressure, it is virtually impossible to make optimal decision taking such causalities into account. As a result, the computerization of taking recovery actions is needed. Considering the requirement of such computerization, the autonomous system in collaboration with human (what we call the agent system) that is still effective even in such a unforeseen condition in NPP is proposed.

Graphical Representation of Nuclear Incidents/Accidents by Associating Network in Nuclear Technical Communication

Nuclear Information Archives (NUCIA) is a service for information disclosure toward the public on nuclear power plants in Japan. This paper focuses on an experience of how information stored in the NUCIA database is processed for information sharing by a “sociotechnical interface,” the interface to the general public. Information on nuclear accidents was analyzed by market basket analysis and mapped to some graphical representation in the website for comprehension. The resultant data obtained by questionnaire survey suggests that this graphical conversion is effective for letting the public understand nuclear accidents. In this sense, this attempt gives significant hints of “how technical communication to the public” should be.

Computerised Procedure Generation

Abstract This paper reports from a project to develop a system for computerised procedure generation. The purposes of the system are to ensure procedures that are consistent and complete, and to facilitate the revision of procedures caused by changes to the plant. The approach makes a fundamental distinction between procedure presentation and procedure generation, and between the various types of knowledge needed to write a procedure. A system has been specified which generates a procedure to accomplish a specific goal, based on plant operations knowledge. The output is an intermediate procedure format, which can be further processed by a computerised procedure presentation system. The system is presently being implemented, and will be evaluated by professional nuclear power plant operators using a Steam Generator Tube Rupture scenario.

Enhancing the plausibility of law equation discovery through cross check among multiple scale-type-based models

The study in the field of scientific discovery from data has been directed to the discovery of plausible law equations representing the first principles underlying objective systems. In this paper, a novel principle and an algorithm to predictively discover new scientific law equation formulae consisting of newly given quantities are proposed based on the candidate law equations governing the other quantities under current observation. The first principle-based scientific law equation formulae must follow some mathematical admissibility and consistency. These conditions enable efficient reasoning of the law equation formulae in the prediction process. The soundness and the reproducibility of the equation prediction by this approach have been tested through numerical simulations of physical examples, and, moreover, its practicality has been confirmed through a real socio-psychological analysis. The approach can discover a set of scientific law equations representing common first principles under different set of quantities, and enables to capture general scietific features of the objective system under analysis.