• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.466-468
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• 2012

선박산업에서의 국내외 해양사고 통계에 의하면, 모든 해양사고의 80% 정도가 직접적 또는 간접적으로 관련된 인적요인(Human Factors)에 의하여 발생한다고 보고되고 있다. 이러한 해양사고의 원인을 규명함으로써 유사 해양사고의 발생을 방지하고, 또한, 해양사고 조사에 있어서 공통적인 접근방법의 이용과 국가 간의 협력을 증진시키기 위한 목적으로, IMO(International Maritime Organization)에서는 해양사고 인적요인 조사지침(Guidelines for the Investigation of Human Factors in Marine Casualties and Incidents)을 포함한 해양사고조사코드(Casualty Investigation Code: Code of the International Standards and Recommended Practices for a Safety Investigation into a Marine Casualty or Marine Incident)를 채택하였으며, 동 코드는 2010년 1월 1일 발효되었다. 이에 따라, 해양안전심판원에서는, 3단계 절차로 구성된 인적요인 조사 및 분석 방법론을 제안하고, "해양사고 인적요인 분석 매뉴얼"을 마련하였다. 본 논문에서는, 해양안전심판원에서 제안한 인적요인 조사 및 분석 방법론을 실제 해양사고에 적용하여 인적요인 조사분석 모델의 적용사례를 마련하고, 분석 모델을 검토 및 보완하고자 한다.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.41-48
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• 2014

This paper provides the design of system software for the management of radiation dose that is generated by using computerized tomography(CT). Recently, the radiation leakage incident of Japanese nuclear power plant was in the news internationally and there is a growing interest not only in nuclear power plant but in medical radiation exposure. In spite of the fact that currently safety management of radiation is under control only the workers of the radiation involved, now the exposure management of patients have been required. As surgery and inspections using the radiation have increased, this medical radiation exposure is increasing too. But it is a real situation that medical institutions don't know the level of radiation exposure applied to the patient. Therefore, a system for managing the radiation exposure of a patient from the medical institution is required. This paper proposes a design of a software program that manages the radiation exposure of CT which is a typical imaging tool to use the radiation in the medical institution. By check the amount of radiation dose and set the limit of dose, we would be of help to optimize the medical exposure of the patient.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.673-681
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• 2014

Due to the increased demand for safety and security requirements on the port infrastructure, the harbor tranquility is one of the important parameter in the mooring basin of harbor. It relates keenly to berthing/unberthing and cargo handling works but also it is an important indicator to get the minimum water area as the safe refuge. Hupo harbor is a national coastal harbor located in east coast of Korea and a development plan for a new marina near the entrance is being carried out including berth layouts, breakwater extensions, 300m marina berths, dredging and land reclamation works. The new plan will impact on calmness of the existing port. Therefore, it is necessary to analyze in complex the variation of wave height and direction caused by wave refraction, diffraction, shoaling and reflection from the incident waves from outside the harbor. In order to check the calmness inside a harbor, the numerical models are being used currently need fundamental reviews according to the difference of results which depend on their respective features. In this study, hence, it was introduced the validity of numerical models by comparing the computational results with the hydraulic model experiment. The current investigations contribute to the existing development recommendations and provide further solutions for port planning.

• Journal of Internet Computing and Services
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• v.18 no.2
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• pp.31-42
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• 2017

As Internet banking service became popular, many users can exchange goods by online. Even though this advantage, there are incident cases in the Internet banking service due to security threats. In order to counteract this problem, various security techniques have been applied over whole area in the Internet banking service. Therefore, we described that analyzed results of security techniques applied in the financial institutions area and network communication area in this paper. We consider that this paper will be useful as a reference to protect security threats occurred by insiders and vulnerabilities in implementation.

• The Korean Journal of Applied Statistics
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• v.30 no.5
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• pp.759-774
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• 2017

Earthquake concerns have grown after a remarkable earthquake incident on September 12th, 2016 in Gyeongju, Korea. Earthquake forecasting is gaining in importance in order to guarantee infrastructure safety and develop protection policies. In this paper, we adopt a power-law distribution model to fit past earthquake occurrences in Korea with various historical and modern seismological records. We estimated power-law distribution parameters using empirical distributions and calculated the future probabilities for large earthquake events based on our model. We provide the probability that a future event has a larger magnitude than given levels, and the probability that a future event over certain levels will occur in a given period of time. This model contributes to the assessment of latent seismological risk in Korea by estimating future earthquake probabilities.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.91-97
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• 2006

Currently, approx. 10,532 turnouts were installed on the KR line, of which 3,644 turnouts were installed in the main line where high speed operation is performed. This shows that it is necessary to improve the performance of turnout as one of vulnerable areas for the safe operation of a train. Even though the number of railway accidents is decreasing every year due to the renewal of railway facilities, there are still many factors that cause the occurrence of an accident. In particular, an incident in turnout area does not only have a high risk of a serious accident but also affect the operation of a train on the adjacent track in most cases, and consequently a big social loss is expected due to the delay in train operation as well as the loss of life and property. The objective of this study is to examine the accidents occurred in turnout area that is one of typical　vulnerable areas over the past ten years, on the basis of the results, and to take an appropriate measure by finding out the major cause of accidents in turnout area so that a systematic safety system can be established to prevent or reduce accidents in turnout area.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.214-214
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• 2015

Rainfall induced landslides is one of the most devastating natural disasters acting on mountainous areas. In Korea, landslide damage areas increase significantly from 1990s to 2000s due to the increase of both rainfall intensity and rainy days in addition with haphazard land development. This study was carried out based on the application of TRIGRS unsaturated (Transient Rainfall Infiltration and Grid-based Regional Slope stability analysis), a Fortran coded, physically based, and numerical model that can predict landslides for areas where are prone to shallow precipitation. Using TRIGRS combining with the geographic information system (GIS) framework, the landslide incident happened on 27th, July 2011 in Mt. Umyeon in Seoul was modeled. The predicted results which were raster maps showed values of the factors of safety on every pixel at different time steps show a strong agreement with to the observed actual landslide scars in both time and locations. Although some limitations of the program are still needed to be further improved, some soil data as well as landslide information are lack; TRIGRS is proved to be a powerful tool for shallow landslide susceptibility zonation especially in great areas where the input geotechnical and hydraulic data for simulation is not fully available.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.304-308
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• 2012

This paper presents a numerical investigation on propagation of hydrocarbon (ethylene-air mixture) detonation in a deformable copper tube. In this study, we deal with interactions of multi-materials, gas and solid. In gas phase, the model consists of the reactive compressible Navier-Stokes equations and one step chemical reaction. Also we use Inviscid Euler equations in solid. In order to the interface tracking and the determination of boundary values, our model handle level-set and ghost fluid method. Through the numerical simulation results, we identify generations of expansion waves and interferences by the wall deformation. In addition, we predict the minimum copper tube thickness that ensures safety under an incident detonation.

• Current Optics and Photonics
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• v.4 no.4
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• pp.330-335
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• 2020

We have investigated optimization of the working distance (WD) for a highly miniaturized imaging probe for endoscopic optical coherence tomography (OCT). The WD is the axial distance from the distal end of the imaging probe to its beam focus, which is demanded for dimensional margins of protective structures, operational safety, or full utilization of the axial imaging range of OCT. With an objective lens smaller than a few hundred micrometers in diameter, a micro-optic imaging probe naturally exhibits a very short WD due to the down-scaled optical structure. For a maximized WD careful design is required with the optical aperture of the objective lens optimally filled by the incident beam. The diffraction-involved effect was taken into account in our analysis of the apertured beam. In this study, we developed a simple design formula on the maximum achievable WD based on our diffraction simulation. It was found that the maximum WD is proportional to the aperture size squared. In experiment, we designed and fabricated very compact OCT probes with long WDs. Our 165-㎛-thick fiber-optic probes provided WDs of 3 mm or longer w ith reasonable OCT imaging performance.

• Journal of the Korean Solar Energy Society
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• v.39 no.4
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• pp.25-39
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• 2019

Luminescent solar concentrator (LSC), consisting of luminophore included glass or substrate with edge-mounted photovoltaic cell, is semi-transparent, energy harvesting devices. The luminophore absorbs incident solar light and re-emit photons, while the waveguide plate allows re-emitted photons to reach edge or bottom mounted photovoltaic cells with reduced losses. If the area of LSC is much larger than that of photovoltaic cell, this system can effectively concentrate solar light. In order to improve the performance of LSC, new materials and optical structures have been suggested by many research groups. For decreasing re-abosprion losses, it is essential to minimize the overlap between absorption and photoluminescence solar spectrum of luminophoroe. Moreover, the combination of selective top reflector and reflective optical cavity structure significantly boosts the waveguide efficiency in the LSC. As a result of many efforts, commercially available LSCs have been demonstrated and verified in the outdoor. Also, it is expected to generate electricity in buildings by replacing conventional glass to LSCs.