• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1804-1810
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• 2011

It is necessary to adopt some logical techniques and methods of alarm processing for a large complex plant such as nuclear power plants in order to present the occurred alarm messages properly and concisely. Among such alarm processing techniques, the alarm suppressing function is a strong tool to avoid alarm flooding during the sudden transients of plant output power such as turbine trips, reactor trips and other incidents. Unless any suppression or representation technologies are used in an alarm message listing system, it cannot provide quick assistance to plant operators or supervisors during plant upsets because too many alarm messages are presented in an alarm list window. This paper presents the key suppression methods and analysis processes developed for implementing a suppressed alarm message listing function of an integrated alarm system called LogACTs which has been applied to a CANDU nuclear power plant. A simulation testing of the suppressing function conducted with the real plant alarm message list data has demonstrated an effective performance of the developed logics with the high suppression rate.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.363-375
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• 2021

The purpose of this study is to analyze the safety of evacuation using the Pathfinder program for the alert at once, the priority alarm method, the priority alarm method for the four floors above, and the sequential priority alarm method, which is a modification of the priority alarm method specified in the tourist hotel building. Currently, in Korea's National Fire Safety Codes (NFSC), fire alarm methods are compulsorily applied differently depending on the number of floors and total floor area of a building. Although the growth rate is getting faster due to the diversification of building structures, it is still an obstacle to improving evacuation safety to comply with the standardized fire alarm method in NFSC. As a result of the experiment, the evacuation time was found to be faster with the priority alarm method for the four floors above than the priority alarm method applied to the specific firefighting object. Compared to the priority alarm method applied to the tourist hotel, which is a specific firefighting target with 5 or more floors and a total floor area of more than 3,000m2, the time was shortened by 3.7 seconds when measured by applying the priority alarm method for the four floors directly above. This indicates that it is necessary to take measures to select a fire alarm method suitable for the structure and environmental conditions of the building rather than applying the uniform NFSC regulations.

• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.69-75
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• 2013

Objective: This study proposes an alarm display and compares it with the one(alarm tile display) widely used in main control rooms(MCRs) of nuclear power plants. Background: Catching up with the rapid development of computer technologies, advanced MCRs has been required. Using modern technologies of computers and visual displays, we have a lot of potential to improve user performance and satisfaction as well as safety in MCRs. Method: The alarm bar display has been proposed to reduce some potential problems of the alarm tile display in this study. Human factors evaluations were conducted to compare both types of displays. Two interfaces of bar alarm and tile alarm were simulated on the desktop computer for the user-involved experiment. Eight students participated in the experiment with the within-subject design. Results: The alarm bar was slightly better in terms of situation awareness, and preferred to understand alarm dynamics. The alarm tile was slightly or significantly better in other measures. Conclusion: Both alarm displays have their own advantages and disadvantages. Therefore, combining benefits of both displays can be used to optimize the design of alarm displays. Application: The proposed display is expected to compensate the existing displays for certain purposes.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3716-3724
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• 2023

Loose parts monitoring and detecting alarm type in real Nuclear Power Plant have challenges such as background noise, insufficient alarm data, and difficulty of distinction between alarm data that occur during start and stop. Although many signal processing methods and alarm determination algorithms have been developed, it is not easy to determine valid alarm and extract the meaning data from alarm signal including background noise. To address these issues, this paper proposes a denoising autoencoder-based majority vote classification. Training and test data are prepared by acquiring alarm data from real NPP and simulation facility for data augmentation, and noisy data is reproduced by adding Gaussian noise. Using DAEs with 3, 5, 7, and 9 layers, features are extracted for each model and classified into neural networks. Finally, the results obtained from each DAE are classified by majority voting. Also, through comparison with other methods, the accuracy and the false alarm rate are compared, and the excellence of the proposed method is confirmed.

• Journal of Aquaculture
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• v.12 no.1
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• pp.63-69
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• 1999

A series of experiments were conducted to examine on what stimulus giant danio (Danio malabaricus) were mainly responsible for detecting alarm substance. When 0.15 ml alarm substance (10 ppm) was introduced into the tank, fish showed no notable change in swimming pattern. However, the introduction of 1.5 ml alarm substance (100 ppm) could induce fright reaction about in 6 minutes. Further, when 15 ml alarm substance (1,000 ppm) was introduced into the tank, fish showed the following fright reaction in a few seconds; suppressing to feed diet, no swimming, strong chasing, and visual alertness. In detecting alarm substance, fish were mainly depending on the chemical stimulus (nares) rather than the vision stimulus (eyes) because fish detected alarm substance by the chemical cue showed the significantly stronger fright reaction than by the visual cue. The time for fish to show the initial fright reaction after detecting alarm substance by the chemical cue was shorter than by the visual cue. Also after alarm substance was introduced into the tank, olfaction-deprived fish showed significantly weaker fright reaction and less frequency of chasing than the normal fish which detected alarm substance by both olfaction and gustation stimulus. These results indicated that chemical stimulus, especially olfaction might be the primary sensory modality used in the detection of the alarm substance for giant danio.

• Journal of the Korean Society of Safety
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• v.37 no.2
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• pp.69-75
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• 2022

Fire-alarm systems are safety equipment that facilitate rapid evacuation and early suppression in case of fire. It is highly desirable that fire-alarm systems have low false-alarm rates and are thus reliable. Until now, researchers have attempted to improve detector performance by applying new technologies such as IoT. To this end, IoT-based fire-detection systems have been developed. However, due to scarcity of large-scale operational data, researchers have barely studied malfunctioning in fire-alarm systems or attempted to reduce false-alarm rates in these systems. In this study, we analyzed false-alarm rates of smoke/temperature detectors and unwanted fire-alarm signal patterns at K institution, where Korea's largest IoT-based fire-detection system operates. After analyzing the fire alarm occurrences at the institution for five years, we inferred that the IoT-based fire-detection system showed lower false-alarm rates compared to the automatic fire-detection equipment. We analyzed the detection pattern by dividing it into two parts: normal operation and unwanted fire alarms. When a specific signal pattern was filtered out, the false-alarm rate was reduced to 66.9% in the smoke detector and to 46.9% in the temperature detector.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.658-661
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• 2005

In many fire emergencies, the auditory fire alarm signals are very important to save the occupant's life. But as the sound insulation of building elements has been improved, it is more difficult for occupant to recognize the fire alarm signals when the audible fire alarm worked. This is the first study to show the sound attenuation of audible fire alarm device in apartments. We measured and analyzed the sound attenuation level in seven units. The result showed that it was not sufficient to detect the sound from the fire alarm device in bedrooms. Whether the fire alarm device worked or not, the differences of sound level in bedrooms were below 1$\sim$10dBA. To give the minimum sound level 60dBA in bedrooms, the proper sound levels from alarm device installed in livingrooms were suggested using computer simulation.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.185-190
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• 1995

Conventional alarm system has many difficulties in the operator's identifying the plant status during special situations such as design basis accidents. To solve the shortcomings, an on-line alarm annunciator system, called dynamic alarm console (DAC), was developed. In the DAC, a signal is generated as alarm by the use of an adaptive setpoint check strategy based on operating mode, and time delay technique is used not to generate nuisance alarms. After alarm generation, if activated alarm is a level precursor alarm or a consequencial alarm, it would be suppressed, and the residual alarms go through dynamic prioritization which provide the alarms with pertinent priorities to the current operating mode. Dynamic prioritization is achieved by going through the system- and mode-oriented prioritization. The DAC has the alarm hierarchical structure based on the physical and functional importance of alarms. Therefore the operator can perceive alarm impacts on the safety or performance of the plant with the alarm propagation from equipment level to plant functional level. In order to provide the operator with the most possible cause of the event and quick cognition of the plant status even without recognizing the individual alarms, reactor trip status tree (RTST) was developed. The DAC and the RTST have been simulated with on-line data obtained from the full-scope simulator for several abnormal cases. The results indicated that the system can provide the operator with useful and compact information fur the earlier termination and mitigation of an abnormal state.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.9
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• pp.351-358
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• 2006

In this paper, DSPOCS(Digital Switchgear-Panel Operation and Control Solution) is designed, which is the intelligent inference based operation and control solution to obtain the safety and reliability of electric power supply in substation based on IED. DSPOCS is designed as a scheduled monitoring and control task and a real-time alarm inference task, and is interlinked with BRES(Bus Reconfiguration Expert System) in the required case. The intelligent alarm inference task consists of the alarm knowledge generation part and the real-time pattern matching part. The alarm knowledge generation part generates automatically alarm knowledge from DB saves it in alarm knowledge base. On the other hand, the pattern matching part inferences the real-time event by comparing the real-time event information furnished from IEDs of substation with the patterns of the saved alarm knowledge base.; Especially, alarm knowledge base includes the knowledge patterns related with fault alarm, the overload alarm and the diagnosis alarm. In order to design the database independently in substation structure, busbar is represented as a connectivity node which makes the more generalized graph theory possible. Finally, DSPOCS is implemented in MS Visual $C^{++}$, MFC, the effectiveness and accuracy of the design is verified by simulation study to the typical distribution substation.

• Journal of Korean Biological Nursing Science
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• v.20 no.4
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• pp.228-235
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• 2018

Purpose: This study aimed to investigate the clinical alarm occurrence and management of nurses toward clinical alarms in the intensive care unit (ICU). Methods: This observational study was conducted with 40 patients and nurses cases in two ICUs of a university hospital. This study divided 24 hours into the unit of an hour and conducted two times of direct observation per unit hour for 48 hours targeting the medical devices applied to 40 patients. Data were analyzed using IBM SPSS Statistics 23. Results: On average, 3.8 units of medical devices were applied for each patient and the ranges of alarm settings were wide. During 48 hours, 184 cases of clinical alarm were occurred by four types of medical devices including physiological monitors, mechanical ventilators, infusion pumps, and continuous renal replacement therapy. Among them, false alarm was 110 cases (59.8%). As for the alarm management by ICU nurses, two-minute alarm mute took up most at 38.0% (70 cases), and no response was second most at 32.6% (60 cases). When valid alarm sounded, nurses showed no response at 43.2%. Conclusion: The findings suggest that a standard protocol for alarm management should be developed for Korean ICU settings. Based on the protocol, continuous training and education should be provided to nurses for appropriate alarm management.