• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.303-306
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• 2007

CWR(Continuous Welded Rail) and bridge interaction produce rail force, bridge displacement and rail/bridge relative displacement. Each of these has limitation by many codes. In this paper, analysis of interaction has been carried out by using foreign codes(UIC 774-3 R code of Europe etc.) because there is no code about interaction between rail and bridge in Korea. Recently, railway bridges with CWR has been constructed for structural and economical reasons. When designer plans railway bridges, design a bridge model first and then investigate railway forces and displacement by interaction analysis. If these results go out bounds from limitation, designer plans railway bridges again and again. In this paper, using the parametric study on CWR and railway bridge interaction, railway bridge parameters such as length of bridge span, area of bridge, moment of inertia, stiffness of pier, etc. are presented. It helps preliminary design of railway bridges.

• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.739-745
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• 2006

The role of maintenance in railway is going to be extended to improve the reliability of railway system in the aspect of Asset management gradually. In this paper, the meaning of reliability and safety in RCM which has been applied in order to improve the efficiency of maintenance is deduced. And the analysis task of reliability and safely which has been recommended in railway standards such as EN50126 and IEC62278 is reviewed in the aspect of RCM. Finally, the several ways are proposed to apply RCM to railway system through the comparison between the RCM procedure and the analysis procedure for the reliability and safety in railway standards. Hereafter, if the analysis of reliability and safety is performed with the concept of RCM in the beginning of railway business, it will be more efficient to improve the reliability and manage the railway asset.

• Journal of the Korean GEO-environmental Society
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• v.18 no.12
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• pp.47-57
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• 2017

In this study, a predictive analysis was conducted on sediment disaster hazard area by selecting six research areas (Chuncheon, Seongnam, Sejong, Daejeon, Miryang and Busan) among the urban sediment disaster preliminary focus management area. The models that were used in the analysis were the existing models (SINMAP and TRIGRS) that are commonly used in predicting sediment disasters as well as the program developed through this study (LSMAP). A comparative analysis was carried out on the results as a means to review the applicability of the developed model. The parameters used in the predictions of sediment disaster hazard area were largely classified into topographic, soil, forest physiognomy and rainfall characteristics. A predictive analysis was carried out using each of the models, and it was found that the analysis using SINMAP, compared to LSMAP and TRIGRS, resulted in a prediction of a wider hazard zone. These results are considered to be due to the difference in analysis parameters applied to each model. In addition, a comparison between LSMAP, where the forest physiognomy characteristics were taken into account, and TRIGRS showed that similar tendencies were observed within a range of -0.04~2.72% for the predicted hazard area. This suggests that the forest physiognomy characteristics of mountain areas have diverse impacts on the stability of slopes, and serve as an important parameter in predicting sediment disaster hazard area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.200-208
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• 2024

The occurrence a fire on a training ship with a large number of people on board can lead to severe casualties. Hence the Seafarers' Act and Safety Life At Sea(SOLAS) emphasizes the importance of the abandon ship drill. Therefore, in this study, the training ship of Mokpo National Maritime University, Segero, which has a large number of people on board, was selected as the target ship and the likelihood and severity of fire accidents on each deck were predicted through the preliminary hazard analysis(PHA) qualitative risk assessment. Additionally, assuming a fire in a high-risk area, a simulation of evacuation time and population density was performed to quantitatively predict the risk. The the total evacuation time was predicted to be the longest at 501s in the meal time scenario, in which the population distribution was concentrated in one area. Depending on the scenario, some decks had relatively high population densities of over 1.4pers/m², preventing stagnation in the number of evacuees. The results of this study are expected to be used as basic data to develop training scenarios for training ships by quantifying evacuation time and population density according to various evacuation scenarios, and the research can be expanded in the future through comparison of mathematical models and experimental values.

• Fire Science and Engineering
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• v.19 no.1 s.57
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• pp.20-28
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• 2005

Major petrochemical companies in the USA and the EU map out the strategies step-by-step hazard evaluation for the efficient risk management. They adopted the risk screening methods, such as Dow fire & explosion index, as a preliminary phase to execute detailed evaluation such as QRA (Quantitative Risk Assessment). In this study, The FEDI (Fire & Explosion Damage Index), which a kind of risk screening method proposed by Khan and Abbasi, was applied to the BTX plant in Korea. We showed that the FEDI can be effectively used to classify the hazard potential by comparison of the result from the FEDI and the result from QRA. And we showed that the characteristics and the quantities of chemical are the factors which have a largest effect on fire and explosion by executing relative sensitivity analysis of the FEDI. In conclusion, if the FEDI was applied as a preliminary phase of HAZOP, more efficient hazard evaluation can be possible.

• Journal of the Korean Geotechnical Society
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• v.30 no.6
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• pp.61-68
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• 2014

The main objective of this study is to evaluate the preliminary landslide hazard based on the identification of geomorphological features, which are believed to be critical values in the initial state of landslides. Two methods, SINMAP and Planarity analyses, are used to simulate those characteristics where landslides are actually located. Results showed that both methods well discriminate geomorphic features between stable and unstable domains in the landslide areas. SINMAP analysis which is the consecutive model considering external factors like infiltration identifies the landslide hazard especially for debris flow type landslides better than plararity analysis focusing on a specific area. This analysis combined with other methods dealing with specific characteristics of geomorphological feature, the accurate landslide hazard will be evaluated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1011-1021
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• 2016

This study performs the potential flood hazard analysis by applying elevation data, soil data and land use data. The susceptibility maps linked to elevation, soil and land use are combined to develop the new types of flood hazard map such as runoff production map and runoff accumulation map. For the development of the runoff production map, land use, soil thickness, permeability, soil erosion and slope data are used as runoff indices. For the runoff accumulation map, elevation, knick point and lowland analysis data are used. To derive an integrated type of flood potential hazard, a TOPSIS (The Technique for Order of Preference by Similarity to Ideal Solution) technique, which is widely applied in MCDM (Multi-Criteria Decision Making) process, is adopted. The indices applied to the runoff production and accumulation maps are considered as criteria, and the cells of analysis area are considered as alternatives for TOPSIS technique. The model is applied to Gamcheon watershed to evaluate the flood potential hazards. Validation with large scale data shows the good agreements between historical data and runoff accumulation data. The analysis procedure presented in this study will contribute to make preliminary flood hazard map for the public information and for finding flood mitigation measures in the watershed.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1635-1643
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• 2022

STPA (System-Theoretic Process Analysis) is a widely used safety analysis technique to identify UCAs (Unsafe Control Actions) resulting in potential losses. It is totally dependent on the experience and ability of analysts to construct an information model called Control Structures, upon which analysts try to identify unsafe controls between system components. This paper proposes a formal approach to support the manual identification of UCAs, effectively and systematically. It allows analysts to mechanically extract Process Model, an important element that makes up the Control Structures, from a formal requirements specification for a software controller. It then concisely constructs the contents of Context Tables, from which analysts can identify all relevant UCAs effectively, using a software fault tree analysis technique. The case study with a preliminary version of a Korean nuclear reactor protections system shows the proposed approach's effectiveness and applicability.

• Korean Journal of Ophthalmology
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• v.32 no.6
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• pp.470-477
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• 2018

Purpose: To investigate the relationship between the progression of visual field (VF) loss and changes in lamina cribrosa depth (LCD) as determined by spectral-domain optical coherence tomography (SD-OCT) enhanced depth imaging in patients with primary open angle glaucoma (POAG). Methods: Data from 60 POAG patients (mean follow-up, $3.5{\pm}0.7$ years) were included in this retrospective study. The LCD was measured in the optic disc image using SD-OCT enhanced depth imaging scanning at each visit. Change in the LCD was considered to either 'increase' or 'decrease' when the differences between baseline and the latest two consecutive follow-up visits were greater than the corresponding reproducibility coefficient value ($23.08{\mu}m$, as determined in a preliminary reproducibility study). All participants were divided into three groups: increased LCD (ILCD), decreased LCD (DLCD), and no LCD change (NLCD). The Early Manifest Glaucoma Trial criteria were used to define VF deterioration. Kaplan-Meier survival analysis and Cox's proportional hazard models were performed to explore the relationship between VF progression and LCD change. Results: Of the 60 eyes examined, 35.0% (21 eyes), 28.3% (17 eyes), and 36.7% (22 eyes) were classified as the ILCD, DLCD, and NLCD groups, respectively. Kaplan-Meier survival analysis showed a greater cumulative probability of VF progression in the ILCD group than in the NLCD (p < 0.001) or DLCD groups (p = 0.018). Increased LCD was identified as the only risk factor for VF progression in the Cox proportional hazard models (hazard ratio, 1.008; 95% confidence interval, 1.000 to 1.015; p = 0.047). Conclusions: Increased LCD was associated with a greater possibility of VF progression. The quantitative measurement of LCD changes, determined by SD-OCT, is a potential biomarker for the prediction of VF deterioration in patients with POAG.

• Journal of Food Hygiene and Safety
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• v.22 no.1
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• pp.15-22
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• 2007

Health functional foods refer to food which manufactured in the form of a tablet, capsule, granule or pill, using materials and ingredients with useful function for a human body in Korea. It needs to be confirmed as safe. Microbiological analyses on 37 samples of botanical raw materials used in the health functional food were performed. Microbiological analyses and probability of irradiation using PSL on 4 samples of aloe powder products were studied. In health functional food ingredients APC was $10^{3}-10^{6}\;CFU/g$ and coliform counts were $10^{2}-10^{5}\;CFU/g$. Among 37 samples B. cereus were found in 12 samples. Four samples of aloe powder products were tested for possible irradiation using preliminary PSL, Two samples of aloe powder products showed positive on preliminary PSL test for irradiation.