• Proceedings of the KSR Conference
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• 2007.05a
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• pp.242-248
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• 2007

In this paper, the basic requirements of catenary in railroad traction is explained. Three different types of catenary suspension systems for different terrains, environments and high speed / low speed trains are presented. The essential requirements of catenary such as reliability, cost effectiveness, maintenance and ruggedness requirements are discussed. The catenary materials and safety problems associated in it are dealt.

• Journal of Aerospace System Engineering
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• v.6 no.3
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• pp.29-33
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• 2012

Until now, The Market of aviation parts had led by OEM(Original Equipment Manufacturer) parts because of aviation industry's nature required higher reliability and safety. But recently, The interest about PMA parts in aviation market is increasing continuously with various environmental changes, such as economic stagnation, oil price rise, development of the manufacture technique and newly rising market of Asia-Pacific region. So, this paper introduces the trend and the requirements of FAA PMA / EASA EPA in order to enhance understanding for certification for aviation parts.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2002.08a
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• pp.82-91
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• 2002

방파제에 대한 신뢰성 설계 방법은 유럽과 일본을 중심으로1980년대 중반 이후로 발전되어 왔다. 유럽에서는 van der Meer(1988a)가 방파제 피복재의 설계에 확률론적인 방법을 도입하였고, Burcharth(1991)는 사석방파제에 대하여 부분안전계수(partial safety factor)를 이용한 신뢰성 설계 방법을 제시하였다 최근 Burcharth and Sørensen(1999)은 PIANC (Permanent International Association of Navigation Congress) Working Groups의 결과를 요약하여 사석방파제와 직립방파제에 대한 부분안전계수들을 확립하였다. (중략)

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1457-1459
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• 2000

The ATO(Automatic Train Operation System) system is equipment for automatic and driverless operation of electric train with minimum control of operator. In this paper, we made ATO system with national technic and passed type test. We are convinced of reliability and safety of the ATO system on the seoul metro 7 line.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.447-454
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• 2000

As the AGT system has never operated in Korea, the construction of test track is essential to the acquisition of safety for the passengers. However, the test track is a synthetic system including vehicle, power system, signalling, track etc, several factors must be considered. In this paper, we suggest the general guideline for the test track of AGT system and test items on test track through the investigation of leading test facilities in the world. Through continuous study and investigation, we finally will build the test track to verify the reliability requirements between the train and infrastructures

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.202-207
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• 2002

The rubber type AGT system is operated by driverless that signaling is CBTC type. The system function is acomplished exactly to obtain the safety and reliability of system and the system is designed to minimize risk. In order to design the system, the functional analysis is performed. Recently functional analysis is performed by RDD-100 which is used and verified by aerospace, military, etc. Therefore, The design tool RDD-100 is used to perform functional analysis in AGT system development project.

• Journal of Biosystems Engineering
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• v.41 no.3
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• pp.153-160
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• 2016

Purpose: This study was conducted to experimentally investigate the structural safety of and identify critical locations in a front-end loader under impact loads. Methods: Impact and static tests were conducted on a commonly used front-end loader mounted on a tractor. In the impact test, the bucket of the front-end loader with maximum live load was raised to its maximum lift height and was allowed to free fall to a height of 500 mm above the ground where it was stopped abruptly. For the static test, the bucket with maximum live load was raised and held at the maximum lift height, median height, and a height of 500 mm from the ground. Strain gages were attached at twenty-three main locations on the front-end loader, and the maximum stresses and strains were measured during respective impact and static tests. Results: Stresses and strains at the same location on the loader were higher in the impact test than in the static test, for most of measurement locations. This indicated that the front-end loader was put under a severe environment during impact loading. The safety factors for stresses were higher than 1.0 at all locations during impact and static tests. Conclusions: Since the lowest safety factor was higher than 1.0, the front-end loader was considered as structurally safe under impact loads. However, caution must be exercised at the locations having relatively low safety factors because failure may occur at these locations under high impact loads. These important design locations were identified to be the bucket link elements and the connection elements between the tractor frame and front-end loader. A robust design is required for these elements because of their high failure probability caused by excessive impact stress.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.4
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• pp.482-488
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• 2019

Leisure and business facilities have been steadily developing in Korea. Among waterborne leisure vessels and equipment, the distribution and sale of kayaks and canoes have significantly increased. Previously, (FRP) materials were primarily employed for constructing kayaks. However, owing to global warming and depletion of natural resources, the demand for non-polluting renewable energy is rapidly increasing, which has increased the demand for carbon fibers. To meet the requirements of changing social consciousness, a carbon fiber-based commercial kayak was designed in this study. Resistance analysis and structural safety were conducted by employing software tool for verifying the reliability of the proposed kayak. The pressure resistance and frictional resistance were examined in a wide range of speed. Obtained results indicate that at speeds greater than 2.6 m/s, the pressure resistance significantly increases and the total resistance also increases. Furthermore, the results corroborate that the proposed kayak structure has a adequate safety with respect to the design loads that are considered during operating conditions.

• Safety and Health at Work
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• v.13 no.3
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• pp.326-335
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• 2022

Background: One of the important actions for enhancing human reliability in any industry is assessing human error probability (HEP). The HEART technique is a robust tool for calculating HEP in various industries. The traditional HEART has some weaknesses due to expert judgment. For these reasons, a hybrid model is presented in this study to integrate HEART with Best-Worst Method. Materials Method: In this study, the blasting process in an iron ore mine was investigated as a case study. The proposed HEART-BWM was used to increase the sensitivity of APOA calculation. Then the HEP was calculated using conventional HEART formula. A consistency ratio was calculated using BWM. Finally, for verification of the HEART-BWM, HEP calculation was done by traditional HEART and HEART-BWM. Results: In the view of determined HEPs, the results showed that the mean of HEP in the blasting of the iron ore process was 2.57E-01. Checking the full blast of all the holes after the blasting sub-task was the most dangerous task due to the highest HEP value, and it was found 9.646E-01. On the other side, obtaining a permit to receive and transport materials was the most reliable task, and the HEP was 8.54E-04. Conclusion: The results showed a good consistency for the proposed technique. Comparing the two techniques confirmed that the BWM makes the traditional HEART faster and more reliable by performing the basic comparisons.

• Geotechnical Engineering
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• v.11 no.1
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• pp.9-22
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• 1995

The purpose of this study is to propose safety factors of pile bearing capacity based on the reliability analysis. Each prediction method involves various degrees of uncertainties. To account for these uncertainties in a systematic way, the ratios of the measured bearing capacity from pile load tests to the predicted bearing capacity are represented in the form of a probability density function. The safety factor for each design method is obtained so that the probability of pile foundation failure is less than 10-3. The Bayesian theorem is applied in a way that the distribution using static formulae is assumed to be the A-prior and the distribution using dynamic formulae or wave equation based methods is assumed to be the likelihood, and these two are combined to obtain the posterior which has the reduced uncertainty. The results of this study show that static formulae of the pile bearing capacity using the 5.p.7. N-value as well as dynamic formulae are highly unreliable and have to have the safety factor more than 7.4 : the wave equation analysis using PDA(Pile Driving Analyzer) system the most reliable with the safety factor close to 2.7. The safety factor could be reduced certain amount by adoption the Bayes methodology in pile design.