• Proceedings of the Safety Management and Science Conference
• /
• 2010.11a
• /
• pp.245-256
• /
• 2010

최근 들어 안전관리의 패러다임은 사후분석에서 사전예방으로 바뀌고 있다. 이러한 추세에 맞추어 본질적인 안전관리에 대한 관심이 늘어나고 있다. 공정에 본질적인 안전을 추구하는 방법은 크게 5가지로 나누어 질 수 있으며, 공정의 배치를 통해서 사고를 영향을 최소화하는 방법은 공정의 설계단계에서 적용할 수 있는 좋은 방법이다. 본 연구에서는 공정의 설비가 가지는 위험성을 기반으로 안전거리에 대한 지침을 제시하고 있다. 사고결과와 사고발생빈도를 기반으로 개인적 위험성(Individual Risk: IR)을 계산하였으며, 계산된 값을 기반으로 최적의 안전거리 계산을 수행할 수 있었다. 계산된 IR과 문헌에서 제시된 안전거리를 바탕으로 작업자가 거주하는 건물과 공정경계 까지의 적절한 거리와 설비간의 최적의 거리를 계산하게 된다. Mixed Integer Linear Programming(MILP)를 이용하여 각각설비의 안전거리가 확보된 시설물 배치와 최소 부지 면적 등을 알 수가 있다. 이 연구를 통해 최적화된 부지면적과 파이프라인의 시설물 배치는 물론 공정건설이나 초기 디자인 단계 및 안전성확보측면에서 본질적인 안전을 구현하는데 유용하게 적용될 수 있다.

• Structural Engineering and Mechanics
• /
• v.28 no.1
• /
• pp.1-18
• /
• 2008

The conventional design of bridge piers against scour uses scour equations which involve number of uncertain flow, sediments and structural parameters. The inherent high uncertainties in these parameters suggest that the reliability of piers must be assessed to ensure desirable safety of bridges against scour. In the present study, a procedure for the reliability assessment of bridge piers, installed in main and flood channels, against scour has been presented. To study the influence of various random variables on piers' reliability sensitivity analysis has been carried out. To incorporate the reliability in the evaluation of safety factor, a simplified relationship between safety factor and reliability index has been proposed. Effects of clear water (flood channel) and live bed scour (main channel) are highlighted on pier reliability. In addition to these, an attempt has also been made to explain the failure of Black mount bridge of New Zealand based on its pier's reliability analysis. Some parametric studies have also been included to obtain the results of practical interest.

• Structural Engineering and Mechanics
• /
• v.50 no.3
• /
• pp.305-322
• /
• 2014

Reliability-based design limit states and associated partial load factors provide a consistent level of design safety across bridge types and members. However, limit states in the current AASHTO LRFD have not been developed explicitly for the situation encountered by integral abutment bridges (IABs) that have unique boundary conditions and loads with inherent uncertainties. Therefore, new reliability-based limit states for IABs considering the variability of the abutment support conditions and thermal loading must be developed to achieve IAB designs that achieve the same safety level as other bridge designs. Prestressed concrete girder bridges are considered in this study and are subjected to concrete time-dependent effects (creep and shrinkage), backfill pressure, temperature fluctuation and temperature gradient. Based on the previously established database for bridge loads and resistances, reliability analyses are performed. The IAB limit states proposed herein are intended to supplement current AASHTO LRFD limit states as specified in AASHTO LRFD Table 3.4.1-1.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05a
• /
• pp.542-547
• /
• 1997

In the SSC(Super System Code), the reactivity feedback models of the Doppler effect and fuel axial expansion were modified to evaluate the safety performance of the metal-fueled core. The core radial expansion model was developed and implemented into the code as well. The transient analyses have been performed by the modified SSC for UTOP, ULOHS, ULOF/LOHS, and UTOP/LOF/LOHS events for one of the core design options being considered. Analysis results shows that the reactivity feedbacks can provide an inherent shutdown capability in response to key anticipated events without scram. Development of other reactivity feedback models and validation of these models against experimental data would make the SSC suitable for the assessment of the metal-fueled core safety performance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.8
• /
• pp.1-8
• /
• 2013

The study carried out in this dissertation focuses on the lens structure design and the light distribution for LED safety luminaires using COB type LED module. Lens structures for LED lights has been designed 1) to induce light diffusion by dual process of internal reflection and refraction, 2) to minimize the inherent LED lights' glittering, and 3) to have uniform brightness. The lens designed with the proposed structures function as diffusers for the divergence of the LED lights so that they form a wide angle of view and adjust the light distribution. We designed of lens with stable uniformity factor and average roughness using aspheric optics property. Finally we made the analysis data of the simulated data.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.1112-1117
• /
• 2010

The intelligent safety system for level crossing which employs information and communication technology has been developed in USA and Japan, etc. But, in Korea, the relevant research has not been performed. In this paper, we analyze the cause of railway level crossing accidents and the inherent problem of the existing safety equipments. Based on analyzed results, we design the intelligent safety system which prevent collision between a train and a vehicle. This system displays train approaching information in real-time at roadside warning devices, informs approaching train of the detected obstacle in crossing areas, and is interconnected with traffic signal to empty the crossing area before train comes. Especially, we present the video based obstacle detection algorithm and verify its performance with prototype H/W since the abrupt obstacles in crossing areas are the main cause of level crossing accidents. We identify that the presented scheme detects both pedestrian and vehicle with good performance. Currently, we demonstrate developed railway crossing intelligence system at one crossing of Young-dong-seon line of Korail with Sea Train cockpit.

• Proceedings of the KIEE Conference
• /
• 2006.07e
• /
• pp.91-92
• /
• 2006

The increased use of underground power distribution as opposed to overhead lines contributes to the aesthetics of the downtown areas. But there is an inherent risk of accidental electrocution should there be damage to the insulation of the cable because of heavy rain. Should a pedestrian make contact with this cable indirectly, via a man hole cover, electrocution could result. In this paper, we analyse weaknesses in this low-voltage manhole and propose improvements.

• Nuclear Engineering and Technology
• /
• v.51 no.1
• /
• pp.45-53
• /
• 2019

Thermal-hydraulic passive safety systems (PSSs) are incorporated into many advanced reactor designs on the bases of simplicity, economics and inherent safety nature. Several factors among which are the critical parameters (CPs) that influence failure and reliability of thermal-hydraulic (t-h) passive systems are now being explored. For simplicity, it is assumed in most reliability analyses that the CPs are independent whereas in practice this assumption is not always valid. There is need to critically examine the dependency influence of the CPs on reliability of the t-h passive systems at design stage and in operation to guarantee safety/better performance. In this paper, two multivariate analysis methods (covariance and conditional subjective probability density function) were presented and applied to a simple PSS. The methods followed a generalized procedure for evaluating t-h reliability based on dependency consideration. A passively water-cooled steam generator was used to demonstrate the dependency of the identified key CPs using the methods. The results obtained from the methods are in agreement and justified the need to consider the dependency of CPs in t-h reliability. For dependable t-h reliability, it is advisable to adopt all possible CPs and apply suitable multivariate method in dependency consideration of CPs among other factors.

• Transactions of the Korean hydrogen and new energy society
• /
• v.34 no.6
• /
• pp.722-727
• /
• 2023

There are various types of hydrogen production methods, but among them, the alkaline water electrolysis method produces hydrogen by electrolyzing water, and unlike other methods, it can produce green hydrogen that does not emit pollutants and greenhouse gases. There are many different potential risk factors inherent in the water electrolysis process. So it is necessary to predict an emergency situation in advance and to safely manage and take countermeasures according to the emergency situation. Korea Gas Safety Corporation (KGS) CODE AH271 stipulates legal matters to secure safety, but it is not detalied. Thus it is necessary to take measures to safely control and manage it according to the situation in which an emergency stop is required. In this study, based on KGS CODE and HAZOP for alkaline water electrolysis facilities, factors that can cause emergency situations were derived and countermeasures were prepared.

• Journal of the Korean institute of surface engineering
• /
• v.56 no.6
• /
• pp.371-379
• /
• 2023

Ammonia, which is closely related to our lives, has a significant impact on our lives as a representative substance for crop cultivation. Recently, it has gained attention as an efficient and productive hydrogen/storing substance that can replace fossil fuels. Efforts are being made to utilize it as a renewable energy source through thermochemical and electrochemical reactions. However, the use of ammonia, which encompasses the era, carries inherent toxicity, so a comprehensive understanding of ammonia safety is necessary. To ensure safety in the transportation and storage of ammonia and chemical substances domestically and internationally, national and organizational standards are being developed and provided through documents and simple symbols to help people understand. This review explores the chemical characteristics of ammonia, its impact on human health, and the global trends in safety standards related to ammonia. Through this examination, the paper aims to contribute to the discourse on the safety and risk management of ammonia transport and storage, crucial for achieving carbon neutrality and expanding the hydrogen economy.