• Journal of the Korean Institute of Gas
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• v.22 no.5
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• pp.62-71
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• 2018

According to own investigation conducted by Korea Gas Safety Corporation Gas Safety Research Institute in 2017, the length of underground pipes in domestic high-pressure gas pipelines is approximately 770km, of which 84% is buried in Ulsan and Yeosu industrial complexes. In particular, 56% of underground pipelines have been in operation for more than 20 years. This suggests urgent management of buried high pressure gas pipelines. PHMSA in US and EGIG in Europe, major causes of accidents in buried gas pipelines are reported as third party damage, external corrosion and loss of pipe wall thickness. Therefore, it is important to evaluate whether the defects affect the remaining life of the pipe when defects occur in the pipe. DNV and ASME have evaluated the residual strength of pipelines through the hydraulic rupture test using pipe specimens with artifact flaws. Once the operating pressure is known through the residual strength of the pipe, the wall thickness at the point at which the pipe ruptures is calculated. If we know the accurate rate of corrosion growth, we can predict the remaining life of pipe. In the study, we carried out experiments with A53 Grade.B and A106 Grade.B, which account for 80% of domestic buried pipes. In order to modify the existing model equation, specimens with a defect depth of 80% to 90% was tested, and a formula expressing the relationship between defect and residual strength was made.

• Korean Security Journal
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• no.37
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• pp.51-82
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• 2013

Traffic safety has been dramatically enhanced thanks to recent improvements in traffic environment. Nonetheless, many traffic accidents occur due to unchanging driving practices. Therefore, this study addresses the issues of traffic fine and penalty fine policies, and seek appropriate levels of traffic fines through a public attitude survey. For this purpose, a survey was conducted on 905 adult drivers over 20 years of age from 15 provinces and metropolitan cities. Analysis results are as follows. First, traffic environment in South Korea is generally not safe. Respondents perceive violation of traffic laws such as reckless driving, speeding and drunk and driving as an important cause. Second, 61.6% of respondents experienced over one speeding annually, but only 15.2% of respondents were caught in the last three years. Third, opposition to levels of traffic fines has decreased over the past, and responses were more positive when more information was provided. Fourth, to deter moral hazard of paying traffic fines to avoid traffic penalty points, traffic fines should be at least 50,000~70,000 won higher than penalty fines. Fifth, there was less opposition to implementation of accumulated penalty policy compared to income-based differential fine levels. Sixth, traffic fines for different types of traffic violations need to be reorganized. In conclusion, this study suggests the following policy improvements for the current traffic fine and penalty fine policies for violation of traffic laws. First, enough understanding and consensus must be developed for policy improvements. Second, administrative sanctions such as giving penalty points should be considered rather than financial sanctions. Third, there should be policy improvement for accumulative penalty. Current acts of traffic law violation should be reorganized.

• Proceedings of the ESK Conference
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• 1993.10a
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• pp.46-55
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• 1993

조종사가 수행하는 조종 업무는 여러 정보를 동시에 지각하여 처리하여 야 하는 복잡한 작업으로 구성되어 있어, 조종사에게는 고도의 인간성능이 요구되고 있다. 또한 조종기술을 습득하기 위해서는 많은 훈련시간과 비용 이 소요되며, 조종사의 실수는 치명적인 사고를 초래한다. 따라서 조기에 비행 부적격자를 판별하고, 미흡한 조종 적성을 함양시킬 수 있는 교육 . 훈련 프로그램을 조종 후보생에게 적용시키는 분석적 조종적성 진단 체계 개발은 조 종사의 도태율 감소, 효율적인 비행훈련, 비행 안전사고 감소 등의 측면에서 절실하게 요구되고 있다. 본 연구에서는 조종 업무 수행시 요구되는 여러 인간 기능의 중요도 차이를 조종 적성 평가 체제에 적용하기 위해서, 각 적성 검사 항목들의 상대적 중요도를 분석하고 이의 타당성을 평가하였다. 적성검사 항목의 상대적 중요도 분석은 조종적성검사 계층구조의 각 수준별 쌍체 비교 평가와 AHP(Analytic Hierarchy Process) 분석에 의한 상대적 중요도 산출 및 평가, 그리고 일관성 지수(Consistency Index)에 의한 분석 결과의 조정을 통해 이루어 졌다. 적성검사 항목의 쌍체 비교 평가는 심리기능검사, 비행자질 검사 등 총 29개 적성검사 항목에 대해 검사를 받았고 또한 초등비행 훈련과정을 수료한 조종 학생들에 의해 이루어 졌다. 상대적 중요도를 분석한 결과 심리기능 검사(W=0.30)가 다른 검사에 비하여 조종적성 평가에 중요한 검사로 나타났으며, 세부 항목으로는 주의 분배력(W=0.13), 추적능력(0.06) 등이 상대적으로 중요한 검사 항목으로 나타났다. 또한 상대적 중요도 결과를 적용한 적성검사 성적이 적용하지 않은 적성검사 성적에 비해 비행성적에 대한 예측 능력이 좋은 것으로 평가되었다.al age)가 있다는 것을 의미하는 것이다. 한편, 생산현장에서는 자동화, 기계화가 진보되어 육체적인 노동이 경감된 결과, 중고령자라도 할 수 있는 작업이 많아지고 있다. 또, VDT (Visual Dislay Terminal) 작업과 같은 정보처리 작업의 수요가 증가하여 그 인재의 부족이 지적되고 있다. 따라서 중고령자의 기능을 조사하여 어떠한 작업에 적합한가를 판단하는 것이 중요한 과제로 되었다. 그러나 노동에는 많은 기능이 관여 하고, 그 내용에 따라서 요구되는 기능이 서로 다르기 때문에 노동적응능력의 기본적인 기능으로 보여지는 것에 좁혀서 작업능력의 연령증가 변화에 대하여다원적 평가를 하는 것이 실제적이라고 할 수 있다. 따라서 본 연구에서는 인간이 가지고 있는 다수의 기능중에서 수지교 치성과 연령증가와의 관계를 조사한다. 만약 연령증가 만으로 수지교치성을 평가 할 수 없는 경우에는 어떠한 요인이 수지기민성의 변화에 영향을 미치는가를 검토한다.t list)에서 자동적으로 사건들의 순서가 결정되도록 확장하였으며, 설비 제어방식에 있어서도 FIFO, LIFO, 우선 순위 방식등을 선택할 수 있도록 확장하였다. SIMPLE는 자료구조 및 프로그램이 공개되어 있으므로 프로그래머가 원하는 기능을 쉽게 추가할 수 있는 장점도 있다. 아울러 SMPLE에서 새로이 추가된 자료구조와 함수 및 설비제어 방식등을 활용하여 실제 중형급 시스템에 대한 시뮬레이션 구현과 시스템 분석의 예를 보인다._3$", chain segment, with the activation energy of carriers from the shallow trap with 0.4[eV], in he amorphous regions.의 증발산율은 우기의 기상자료를 이용하여 구한 결과

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.731-736
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• 2021

Oil fences effectively prevent the spread of oil spilled in the sea, thereby reducing the damage to the marine environment. However, the fence is damaged by oil and structures at the accident site and is discarded. When incinerated disposal method for discarded fences, fine dust, and harmful materials are generated. Moreover, as a part of the damaged fence is dumped into the sea, it may cause secondary environmental pollution, such as microplastics. Therefore, in this study, durability was measured using the most common solid foam type oil fences. As a result, the reduction rate of after five days of contact was 13 % in seawater and 3 % in oil, affected by temperature changes. Thus, the durability of the fence should be improved because it is exposed to seawater and oil and affected by wind, light, and waves depending on the weather conditions. Therefore, we suggest a method to improve the oil fence inspection to strengthen the durability of the fence's fabric part.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.447-452
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• 2020

Extratropical cyclone in winter season is very important in safe operation of ships because it is a major cause of marine accidents due to its strong power. In this study, we used meteorological data, to analyze extratropical cyclones occurring near the 1st Pacific polar front from December 2019 to February 2020. The analysis results are as follows. During those three months, we recorded 41 extratropical cyclones, 8 of which were remarkably developed. The central pressure of the strongest cyclone was 947hPa. The highest number of cyclones were generated in the East P acific Ocean around J apan (16), followed by the areas around Korea, the East China Sea, and the southern Sea of J apan. The cyclones followed five major tracks with a common northeast pattern. We thus concluded that the optimal route for a ship encountering an extratropical cyclone in the North P acific in winter would be south of the cyclone's center traveling eastbound and north of the center traveling westbound.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.6
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• pp.853-861
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• 2018

This paper proposes the application of harmonic constraints to address the problems caused by abnormal voltage increases when electric railway vehicles are running. The AC line that supplies the train with power during operation is used to provide electricity of 25kV/60 Hz, but gradually the size and frequency of harmonics involved in the line are varied with the technological evolution of the railroad vehicle electrical equipment. An increase in heat losses due to the failure of the instrument transformer (PT), the main circuit device, which is a serious problem with the recent train safety operation, or to the main displacement voltage. When high frequency components are introduced through low frequency Transformers of the main circuit device, the high intensity of the components is caused by the high intensity of the core and the current flow of the parasitic core is increased, thus generating heat. To solve this problem, the recent adjustment of the sequence has applied artificial NOTCH OFF of the power converter. However, the method of receiving and controlling the OFF signal operates by interaction between the ground and the vehicle's devices, thus it is invalid in the event of failure, and an actual accident is occurring. Therefore, the harmonic currents were required to prevent possible flow of harmonics, and conducted a study to prevent accidental occurrence of train accidents and to verify feasibility of the device through the simulations of the train's experimental analysis and the simulations of the train for safe operation.

• Journal of the Society of Disaster Information
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• v.19 no.4
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• pp.916-923
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• 2023

Purpose: Looking at the status of fatal accidents in the construction industry in the 2022 Industrial Accident Status Supplementary Statistics, 27.8% of all fatal accidents in the construction industry are caused by construction equipment. In order to overcome the limitations of tours and inspections caused by the enlargement of sites and high-rise buildings, we plan to build a model that can extract construction equipment using computer vision technology and analyze the model's accuracy and field applicability. Method: In this study, deep learning is used to learn image data from excavators, dump trucks, and mobile cranes among construction equipment, and then the learning results are evaluated and analyzed and applied to construction sites. Result: At site 'A', objects of excavators and dump trucks were extracted, and the average extraction accuracy was 81.42% for excavators and 78.23% for dump trucks. The mobile crane at site 'B' showed an average accuracy of 78.14%. Conclusion: It is believed that the efficiency of on-site safety management can be increased and the risk factors for disaster occurrence can be minimized. In addition, based on this study, it can be used as basic data on the introduction of smart construction technology at construction sites.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.116-118
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• 2023

In recent years, the need for economical and sustainable ship routing has emerged due to the enforced regulations on environmental issues. Despite the development of weather forecasting technology, maritime accidents by rough waves have continued to occur due to incorrect weather forecasts. In this study, onboard measurements are conducted to observe the acutal situation on merchant ships in operation encountering rough waves. The types of measured data include information related to navigation (Ship's position, speed, bearing, rudder angle) and engine (engine revolutions, power, shaft thrust, fuel consumption), weather conditions (wind, waves), and ship motions (roll, pitch, and yaw). These ship experiments was conducted to 28,000 DWT bulk carrier, 63,000 DWT bulk carrier, 20,000 TEU container ship, and 12,000 TEU container ship. The actual ship experiment of each ship is intended to acquire various types of data and utilize them for multi-objective studies related to ship operation. Additionally, in order to confirm the sea conditions, the directional wave spectrum was reproduced using a wave simulation model. Through data collection from ship experiments and wave simulations, various studies could be proceeding such as the measurement for accurate wave information by marine radar and analysis for cargo collapse accidents. In addition, it is expected to be utilized in various themes from the perspective of safety and efficiency in ship operation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4855-4862
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• 2015

This paper proposes low price power component measurement and record system for preventing electrical safety accident and supporting accident cause analysis by periodically monitoring and recording the operation status of electrical equipments. The proposed system was designed by mainly using parts to measure accurate power component but reduce cost. Especially, low cost and high effectiveness system implementation was possible by using MAXIM 78M6631 to calculate power components in the definition of IEEE Standard 1459-2010 related power quality. The measurement performance of the developed system is tested by using standard devices such as YOKOGAWA power analyzer WT1600. The test results showed that accuracy of the developed system is less than 0.5 % and the developed system is tested in a real area to verify the operation reliability and remote monitoring performance of the system over 6 months.

• The Journal of the Korea Contents Association
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• v.15 no.11
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• pp.115-125
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• 2015

This study was to identify major risk factors associated with secondary traumatic stress in a sample of 654 public social welfare specialists. Findings indicated that 69.0% of the subjects experienced secondary traumatic stress, and 36.9% of them were in a high-risk group. Multiple regression analysis showed that the risk of the secondary traumatic stress was associated with gender, work hours, physical violence and threats from clients, coping strategies, and vocational self-efficacy. Based on these results, several interventions for preventing the incidence of secondary traumatic stress among public social welfare specialists are suggested as the follows: construction of secure job environment, development of educational programs for improving vocational self-efficacy and coping skills, and implementation of mental health screening system on a regular basis to prevent the outbreak of mental disease among the workers.