• Journal of KIISE
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• v.43 no.8
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• pp.848-856
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• 2016

Seeking and recognizing maritime targets are very important tasks for maritime safety. While searching for maritime targets using radar is possible, recognition is conducted without automatic identification system, radio communicator or visibility. If this recognition is not feasible, radar operator must tediously recognize maritime targets using movement features on radar base on know-how and experience. In this paper, to support the radar operator's mission of continuous observation, we propose an algorithm for automatic recognition of an unknown ship using movement features on radar and a method of detecting potential ship related accidents. We extract features from contact range, course and speed of four types of vessels and evaluate the recognition accuracy using SVM and suggest a method of detecting potential ship related accidents through the algorithm. Experimentally, the resulting recognition accuracy is found to be more than 90% and presents the possibility of detecting potential ship related accidents through the algorithm using information of MV Sewol. This method is an effective way to support operator's know-how and experience in various circumstances and assist in detecting potential ship related accidents.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3620-3630
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• 2022

The diagnosis of abnormalities in a nuclear power plant is essential to maintain power plant safety. When an abnormal event occurs, the operator diagnoses the event and selects the appropriate abnormal operating procedures and sub-procedures to implement the necessary measures. To support this, abnormality diagnosis systems using data-driven methods such as artificial neural networks and convolutional neural networks have been developed. However, data-driven models cannot always guarantee an accurate diagnosis because they cannot simulate all possible abnormal events. Therefore, abnormality diagnosis systems should be able to detect their own potential misdiagnosis. This paper proposes a rulebased diagnostic validation algorithm using a previously developed two-stage diagnosis model in abnormal situations. We analyzed the diagnostic results of the sub-procedure stage when the first diagnostic results were inaccurate and derived a rule to filter the inconsistent sub-procedure diagnostic results, which may be inaccurate diagnoses. In a case study, two abnormality diagnosis models were built using gated recurrent units and long short-term memory cells, and consistency checks on the diagnostic results from both models were performed to detect any inconsistencies. Based on this, a re-diagnosis was performed to select the label of the second-best value in the first diagnosis, after which the diagnosis accuracy increased. That is, the model proposed in this study made it possible to detect diagnostic failures by the developed consistency check of the sub-procedure diagnostic results. The consistency check process has the advantage that the operator can review the results and increase the diagnosis success rate by performing additional re-diagnoses. The developed model is expected to have increased applicability as an operator support system in terms of selecting the appropriate AOPs and sub-procedures with re-diagnosis, thereby further increasing abnormal event diagnostic accuracy.

• Journal of the Korean Society of Radiology
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• v.18 no.1
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• pp.11-20
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• 2024

As the importance of intervention has recently increased, interest in the health of medical staff performing the procedure is increasing. Existing radiation shielding devices have limited the operator's movement and have not been properly used due to the risk of infection, and adequate radiation shielding of the operator's gonads and furthermore, the entire area of the procedure room has not been achieved. An auxiliary shielding device was manufactured by attaching a Bismuth to the elbow support used in the procedure, and the radiation shielding effect was measured. As a result of the measurement, the average spatial dose rate decreased by about 64.8%, and the independent sample t-test analysis showed statistically significant below the significance probability (p<0.05). The use of an auxiliary shielding device is considered to be an effective shielding method that can shield the operator's gonads and reduce the radiation spatial dose rate of the entire area of the procedure room.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.203-205
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• 2005

A reactor protection system (RPS) plays the roles of generating the reactor trip signal and the engineered safety features (ESF) actuation signal when the monitored plant processes reach predefined limits. A Korean project group is developing a new digitalized RPS and the Cabinet Operator Module (COM) of the RPS which is used for the RPS integrity testing and monitoring by an equipment operator. A flat panel display (FPD) with a touch screen capability is provided as a main user interface for the RPS operation. To support the RPS COM user interface design, actually the FPD screen design, we developed a user interface style guide because the system designer could not properly deal with the many general human factors design guidelines. To develop the user interface style guide, various design guideline gatherings, a walk-though with a video recorder, guideline selection with respect to user interface design elements, determination of the properties of the design elements, discussion with the system designers, and a conversion of the properties into a screen design were carried out. This paper describes the process in detail and the findings in the course of the style guide development.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1759-1764
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• 2005

Human Adaptive Mechatronics(HAM) is a new concept which was proposed in our university's research project sponsored by Japanese Ministry of Education, Sports, Culture, Science and Technology(MEXT), and is defined as "intelligent mechanical systems that adapt themselves to the user's skill under various environments, assist to improve the user's skill, and assist the human-machine system to achieve best performance". In this paper, the concept and key-items of HAM are mentioned. And the control strategy to realize a HAM human-machine system is explained in the case of physical-interface system, i.e. haptic system. The proposed assist-control of a force-feedback type haptic system includes online estimation of a operator's control characteristics, and a `force assist' function implemented as a change in the support ratio according to the identified skill level. We developed a HAM-haptic device test system, executed evaluation experiments with this apparatus, and analyzed the measured data. It was confirmed that the operator's skill could be estimated and that operator's performance was enhanced by the assist-control.

• Journal of Navigation and Port Research
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• v.45 no.2
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• pp.75-86
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• 2021

This paper intends to evaluate the policies which are considered necessary to enhance the T/S competitiveness of Busan's port, and thereby present suggestions to the government which would best implement the results of this research. This research first raises the claim that the majority of the following four conditions: location of the port, port productivity/service level, status of network with overseas ports, and cost competitiveness, should be satisfied in order to maintain a competitive T/S port. Based on these four conditions, seven policies, which are individually pertinent to the four conditions, have been drawn up for proposal, and they are also analyzed in the survey, where all the eligible samples participate to ensure if they are effective in enhancing the T/S competitiveness of Busan. Proposed important policies are a) Terminal operator integration, b) port infrastructure expansion, c) global carriers owned terminal operation, d) enhancement of national carrier's competitiveness, e) feeder carriers' owned terminal operation in new port, f) institutional support for effective and convenient environments for handling T/S cargo, and g) volume incentive expansion. From the analysis by which all the relevant parties (Carriers, Terminal Operators, Port Authority) are answered, it was found that all the seven policies have relevance in strengthening the transshipment competitiveness of Busan's port. Whereas in the analysis that uses AHP methodology to compare the significance among the different policies, it was found that terminal operator integration has the highest priority in terms of increasing transshipment competitiveness.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1271-1287
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• 2022

When abnormal operating conditions occur in nuclear power plants, operators must identify the occurrence cause and implement the necessary mitigation measures. Accordingly, the operator must rapidly and accurately analyze the symptom requirements of more than 200 abnormal scenarios from the trends of many variables to perform diagnostic tasks and implement mitigation actions rapidly. However, the probability of human error increases owing to the characteristics of the diagnostic tasks performed by the operator. Researches regarding diagnostic tasks based on Artificial Intelligence (AI) have been conducted recently to reduce the likelihood of human errors; however, reliability issues due to the black box characteristics of AI have been pointed out. Hence, the application of eXplainable Artificial Intelligence (XAI), which can provide AI diagnostic evidence for operators, is considered. In conclusion, the XAI to solve the reliability problem of AI is included in the AI-based diagnostic algorithm. A reliable intelligent diagnostic assistant based on a merged diagnostic algorithm, in the form of an operator support system, is developed, and includes an interface to efficiently inform operators.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.153-158
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• 1995

All of the nuclear power plants in Korea we operating with analog instrumentation and control (I&C) equipment which are increasingly faced with frequent troubles, obsolescence and high maintenance expenses. Electrical and computer technology has improved rapidly in recent years and has been applied to other industries. So it is strongly recommended we adopt modern digital and computer technology to improve plant safety and availability. The advanced I&C system, namely, Integrated Intelligent Instrumentation and Control System (I$^3$CS) will be developed for beyond the next generation nuclear power plant. I$^3$CS consists of three major parts, the advanced compact workstation, distributed digital control and protection system including Automatic Start-up/shutdown Intelligent Control System (ASICS) and the computer-based alarm processing and operator support system, namely, Diagnosis, Response, and operator Aid Management System (DREAMS).

• Journal of the Korean Society of Safety
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• v.7 no.4
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• pp.95-99
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• 1992

The attraction of using expert system in operator support systems for modern plant is that it offers a way of dealing with the problem of information overload that can occur during a severe disturbance at a modern industrial plant. During such a disturance the volume of information presented to operators may be such that they are unable to decide quickly what is important and what is not. Therefore, arriving at a correct diagnosis of the initialling fault may be delayed. An expert system operator sup-port system is a means of focusing attention on what really matters and cutting out the rest. This paper presents the development of prototype expert system which detect the fault part, machine, system and decide action priority. This prototype expert system has 6 sub- system which is Interface Manager, Decision Maker, Inference Engine, Knowledge base, Simulatio, and D.P System ( Diagnosis and predictor)

• Journal of the Ergonomics Society of Korea
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• v.18 no.3
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• pp.153-169
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• 1999

The design of nuclear control room is advancing toward totally computer based human system interfaces (HSI). Computer based interfaces offer the opportunity to provide improved support of operator performance, but if not properly deployed, can introduce new challenges. This paper reviews the Westinghouse AP-600 Human Factors Verification and Validation Plan selected for HSI evaluation model of Korea next generation nuclear control rooms. The AP-600 HSI evaluation model addressed 15 evaluation issues considering major activity class of operator and task complexity factors. This paper also describes the test procedures experimenters should follow to evaluate the addressed issues.