• Journal of the Korea Safety Management & Science
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• v.15 no.2
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• pp.143-149
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• 2013

Recently in the construction business construction companies has been ordered to survive in the terriblly competitive environment. Aa a result, most of the project with low-priced contract needs a speedy progress during all construction period. For the last five years major incident frequently occurs and results in the death of 189 workers at major top 6 construction builders. In most recent 10 years, the cause of major incidents happened in construction company is the speedy construction work that is affecting on the safety management. To prevent these accidents in the speedy construction work, four factors were chosed and analysed such as the personnel/organization, the working budget, the subcontractor selection and the employee motivation. The head office taked the support plan and tested it at the pilot work site. It showed a reduced accident and the harmful factors can be eliminated. It should be able to apply to the field to secure safety and prevent accidents.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.1
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• pp.23-28
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• 2015

Measuring the distances between signals in the signal space is usually determined by obtaining the ideal metric which is not easy to obtain. In this research we have investigated the scheme that measures the distances between the signals constructed with the measured voltage signals connected to electric apparatus using Kalman filter and exponential mapping. The metric is defined on the feature signals obtained via the estimation process of a Kalman filter and the mapping process using the exponential transformation. Diagnosis is on the voltage fluctuations is applied to determining whether the system is in the stable state or not due to the unexpected accidents, such as power overcharge, discharge, outages flow may be the cause of the accident. The decision making scheme evaluated with respect to the effectiveness and the degree of complication with different variances. Two methods, the Hard Limit Threshold Scheme(HLTS) and the Interval Energy Scheme(IES) are proposed and compared. In experiments the IES shows better tolerance to impulse noise than the HLTS.

• Journal of the Ergonomics Society of Korea
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• v.18 no.1
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• pp.133-147
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• 1999

Traffic signs without a cognitive consideration in their design may cause information-processing problem that could result in a mental confusion among drivers often lead to a serious traffic accident. Therefore, in this study, several traffic signs currently used in Seoul Metropolitan area have been sampled and analyzed to identify design problems that usually caused by neglecting drivers cognitive ability. To classify the practical design problems, five major information-processing problems have been suggested: indistinguishable information, information conflict, missing information, sign-load mismatch, and information overload. In order to solve these cognitive problems, new traffic signs have been suggested in this study. An experiment was also performed to validate the new traffic sign. Twenty-four healthy subjects participated in the experiment. They were asked to answer the Question after observing the traffic signs continuously displayed on computer screen. The result indicated that subjects improved the accuracy in understanding the signs by 1.4 times when they used the suggested traffic sign compared to the old one. Based upon the results, a cognitive guideline was suggested for correct and speedy reading of traffic signs by improving information processing and reducing of human error. In conclusion, the traffic sign may well be applied to design an intelligent traffic sign system to increase the safety and comfort of drivers, especially in complex load condition.

• Journal of Navigation and Port Research
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• v.26 no.3
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• pp.275-280
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• 2002

Vessel collision accidents have been investigated by means of questioning the persons involved and plotting manually the stated situation. But the repetitive plotting by hand can cause the investigator or to make some errors, and it can be connected to a wrong judgement. In this paper, we proposed a simulator for reconstructing and analyzing vessel collision accidents at sea, where the given situation is plotted automatically on it. We verified the validity of the system by applying it to some collision accidents.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.2
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• pp.18-24
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• 2023

According to the results of a survey by Boeing, LOC-I (Loss of Control in Flight) was the highest in the number of deaths by fatality accident category in the past 10 years from 2012 to 2021, and the number of deaths worldwide due to LOC-I accidents was 757. It turned out to be the biggest cause of aircraft fatalities, with a figure close to twice the sum of UNK (Unknown or Undetermined), which is the 2nd place, and CFIT (Controlled Flight Into or Toward Terrain), which is the 3rd place. This study set six scenarios related to spatial disorientation that may occur during sensory-dependent flight targeting student pilots and instructor pilots at domestic designated specialized educational institutions using flight simulation training equipment, and in each scenario, the pilot's. The need for SDRT (Spatial Disorientation Recovery Training) is verified by analyzing the flight experience and recovery ability by qualification, and SDRT is repeatedly performed to verify and present the training cycle and time.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2604-2612
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• 2023

Spent nuclear fuel and long-lived radioactive waste must be carefully handled before disposing them off to a geological repository. After the pre-storage period in water pools, spent nuclear fuel is stored in casks, which are widely used for interim storage. Interim storage in casks is very important part in the whole cycle of nuclear energy generation. This paper presents the results of the numerical study that was performed to evaluate the thermal behavior of a metal-concrete CONSTOR RBMK-1500 cask loaded with spent nuclear fuel and placed in an open type interim storage facility which is under fire conditions (steady-state, fire, post-fire). The modelling was performed using the ANSYS Fluent code. Also, a local sensitivity analysis of thermal parameters on temperature variation was performed. The analysis demonstrated that the maximum increase in the fuel load temperatures is about 10 ℃ and 8 ℃ for 30 min 800 ℃ and 60 min 600 ℃ fires respectively. Therefore, during the fire and the post-fire periods, the fuel load temperatures did not exceed the 300 ℃ limiting temperature set for an RBMK SNF cladding for long-term storage. This ensures that fire accident does not cause overheating of fuel rods in a cask.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.320-326
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• 2009

Providing visual field for a driver is one of the most important things for safe driving. Therefore, it will be a first step fur the safe driving that the driver recognizes front and back outside scenes within short time in the car. Specially, it is essential to take the visual field in frequently foggy area where the traffic accident can cause highest rank in the number of deaths. In this paper, our technique can provide the visual field by displaying the location of neighboring vehicles on the monitoring system, embedded board navigator in the car, using the location information of the vehicles from GPS(Global Positioning System) in real time. It is expected that this system can contribute to help safe driving and to lower collision accidents by guiding to cope with unexpected circumstances.

• Tunnel and Underground Space
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• v.7 no.3
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• pp.191-201
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• 1997

Geological and geotechnical surveys, in general, should precede the excavation to ensure the safety of the tunnel and should be followed up according to the various geological condition during the excavation. However actually the standard support patterns which were decided during the design step used be insisted for the whole excavation steps in spite of the various geological conditions. OO tunnel was excavated with NATM and a support pattern type-V in weak rocks. When the tunnel was excavated up to 25m long, the severe displacement was generated in the portal area and the shotcrete was damaged to make the cracks and the tunnel face was totally collapsed. It might happen owing to the one-day heavy rain, but the exact reason for that accident should be found out and the new optimal support patternt needed. Consequently three dimensional numerical analysis was applied for the evaluation of the cause of the tunnel collapse instead of two dimensional analysis, because three dimensional analysis can show better the real field phenomenon than two dimensional analysis in which the load distribution methods are adopted for the tunnel excavation. We could simulate the actual situations with three dimensional finite difference code and propose the new optimal support patterns.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.4
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• pp.398-413
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• 2011

For railway safety, it is very important to detect damages of rails at their early stage because any undetected damage in a rail can break the rail and cause a serious railway accident. In this paper, several NDT applicable to rail inspections are described. Major damage types in rails are discussed first and the rail inspection technology using conventional piezoelectric ultrasonic transducers, which is widely adopted for damage detection of rails, is explained. Other NDT being researched or tested for rail inspection are also discussed as complementary technologies to the concurrent contact type ultrasonic inspection. Characteristics of each rail inspection technologies are evaluated in order to provide requirements for future development of a new rail inspection method.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.327-340
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• 2015

Purpose : Recently, many quality issues are aroused in military forces, such as failures in K-series weapons, combat uniforms' defects and 40mm ammunition explosion accident. To address these problems, Defense Agency for Technology and Quality(DTaQ) introduced new systems such as Manufacturing Readiness Assessment(MRA), Test Report Information System(TRIS) and so on. However, these activities require the human and time resources which cannot be increased in short period. In this paper, we suggest more practical and efficient product examination method. Methods : The most popular and widely used government's quality assurance technique is a sampling method to examine the product. In this research, we first reviewed the DTaQ's quality assurance regulation, then identified several possible problems and finally suggested more efficient and effective sampling plans. Results : We have suggested new sampling framework and evaluated its performance on two military supplies by comparing with other sampling method, and observed that the number of tested samples can be substantially reduced. Therefore, required quality assurance time can be saved. Conclusion : In this paper, we first reviewed the product examination frameworks of DTaQ, PPQMS and DCMA. Then we identified several possible problems which can cause the loss of objectivity and time. To handle these problems, we suggested the new product examination framework and tested the framework to verify the performance.