• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.341-348
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• 2019

In order to reduce the safety risk of forestry operations, this research was conducted to examine the suitability of chainsaw protective pants after repeated laundering, testing four different products that are currently used in hand-held chainsaw operations. Laundering was repeated 10, 20, 30, 40, and 50 times. After washing, we measured the shrinkage ratio of 17 measurement positions mostly affecting the safety of forest operations and suggested the expected safety life cycle of chainsaw protective clothes. The results showed that most of the products have only one measurement position where the standard shrinkage ratio (<6%) was exceeded after 20 washings, and that the lateral direction of measurement positions shrank more than the vertical one. The numbers of repeated launderings and measurement positions were found to be significant factors influencing the shrinkage ratio (p<0.05). In the shrinkage rates for 17 measurement positions, there were significant correlations between five of the measurement positions (a, b, g, j, and n) and the number of repeated launderings (p<0.05). Therefore, the results suggest that about 10 months would be suitable for an adequate safety lifetime for chainsaw protective pants. The relationship between the number of repeated launderings and the measurement positions will be further analyzed in detail to examine the durability of chainsaw protective pants.

• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.30-36
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• 2022

In commercial transactions of energy sources using hydrogen charging stations, high-accuracy flow meters are needed to prevent accidents such as overcharging due to inaccurate measurements and to ensure transparency in hydrogen commercial transactions through accurate measurements. This research developed a Corioli-type flowmeter prototype and conducted a risk assessment to prevent accidents during a process change comparison experiment for existing charging stations to verify the measurement performance. A process change section was defined for the installation of measurement facilities for empirical experiments and HAZOP was conducted. In addition, JSA was also conducted to secure the safety of experimenters, such as preventing valve mis-opening during empirical experiments. Measures were established to improve the risk factors derived through HAZOP, and work procedures were established to minimize human errors and ensure the safety of workers through JSA. The design change and system manufacturing for the installation of the metering system were completed by reflecting the risk assessment results, and safety could be confirmed through the performance comparison test of the developed meter prototype. The developed prototype flow meter showed a total of 30 flow measurements under the operating conditions of 70 MPa, and the average error was -1.58% to 3.96%. Such a metering error was analyzed to have the same performance as a flow meter installed and operated for commercial use.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.259-261
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• 2002

Recently, according to the spread of semiconductor applied technology like motor speed control contrivance, power conversion installation and so on, harmonic ingredients occurred in switching operation flow into a distribution system and increase voltage distortion of distribution system and bring on obstacles like damage, lowering of capability, false operation and so on of various electrical installation. So, in order to consider a countermeasure to limit occurrence quantity of harmonic source, harmonic interception and others, precision measurement and analysis on voltage, current, power, power factor, the each ingredient of harmonic order, the percentage of total harmonic distortion and so forth are needed. In this paper monitoring system to measure and analyze power quality connected with power harmonics was developed and it's performance is verified by measuring and analyzing three-phase voltage and current of R, S, T in the three-phase and four-wire system using the developed measurement system.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.6
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• pp.407-413
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• 2015

Ultrasonic infrared thermography is an active thermography methods. In this method, mechanical energy is introduced to a structure, it is converted into heat energy at the defects, and an infrared camera detects the heat for inspection. The heat generation mechanisms are dependent on many factors such as structure characteristics, defect type, excitation method and contact condition, which make it difficult to predict heat distribution in ultrasonic infrared thermography. In this paper, a method to simulate frictional heating, known to be one of the main heat generation mechanisms at the closed defects in metal structures, is proposed for ultrasonic infrared thermography. This method uses linear vibration analysis results without considering the contact boundary condition at the defect so that it is intuitive and simple to implement. Its advantages and disadvantages are also discussed. The simulation results show good agreement with the modal analysis and experiment result.

• International Journal of High-Rise Buildings
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• v.7 no.4
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• pp.409-415
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• 2018

Recently, many countries around the world began to show interest in safety against terrorism, fire, and natural disasters. This study aimed to propose a quantitative measurement system for emergency evacuation and safety for various kinds of terrorism and fire within high-rise multi-purpose facilities, which can measure the pedestrians' ordinary walking patterns in the concourse with the highest pedestrian volume out of all the spaces within multi-story buildings, predict pedestrians' evacuation walking lines when a sudden disaster breaks out, and analyze the gait coefficient, occupant density, and evacuation behavior time.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.861-869
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• 2023

This article proposes a novel approach to measure the performance of Safety-Critical Systems (SCS). Such systems contain multiple processing nodes that communicate with each other is modeled by a Petri nets (PN). The paper uses the PN for the performance evaluation of SCS. A set of ordinary differential equations (ODEs) is derived from the Petri net model that represent the state of the system, and the solutions can be used to measure the system's performance. The proposed method can avoid the state space explosion problem and also introduces new metrics of performance, along with their measurement: deadlock, liveness, stability, boundedness, and steady state. The proposed technique is applied to Shutdown System (SDS) of Nuclear Power Plant (NPP). We obtained 99.887% accuracy of performance measurement, which proves the effectiveness of our approach.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.43-44
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• 2022

Recently, there is a demand for a fast and efficient method for measuring displacement during construction or maintenance of new buildings. As the number of safety accidents caused by structural collapse increases, the integrated management plan of the measurement and management system has become a platform and data is shared with stakeholders, so that it is possible to establish safety management in advance according to the displacement of the structure.

• Proceedings of the Safety Management and Science Conference
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• 2006.04a
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• pp.183-187
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• 2006

• Journal of the Korean Society of Safety
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• v.21 no.4 s.76
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• pp.66-72
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• 2006

An accurate knowledge of the AITs(autoignition temperatures) is important in developing appropriate prevention and control measures in industrial fire protection. The measurement of AITs are dependent upon many factors, namely initial temperature, pressure, vessel size, fuel/air stoichiometry, catalyst, concentration of vapor, ignition delay time. The values of the AITs used process safety are normally the lowest reported, to provide the greatest margin of sefety. This study measured the AITs of o-xylene+n-pentanol system from ignition delay time by using ASTM E659-78 apparatus. The experimental AITs of o-xylene and n-pentanol were $480^{\circ}C\;and\;285^{\circ}C$, respectively. The experiment AITs of o-xylene+n-pentanol system were a good agreement with the calculated AITs by the proposed equations with a few A.A.D.(average absolute deviation).

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.22-28
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• 2014

This study is compare to model-based analysis and experimental data of the response characteristic of interior impulse noise. Interior impulse noise and the pressure response characteristics of the building structure on its analysis are presented the impulse pressure acting on the rear wall 90 N-sec. The force acting on the wall $CFD^{{+}{+}}$ which are compared measurement and simulation analysis. Results of simulation and measurement data were shown. In this study, a high dimension of the degree of virtual space in the numerical space of the lesser degree in order to calculate folding method was applied. The results of this study contribute safety evaluation and model development for the interior impulse noise that affects the basic data for the interior impulse noise model validate for the physical quantity prediction.