• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.307-320
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• 2017

The objective of this study is to identify the effectiveness of ESC(Electronic Stability Control) based on a meta analysis technique. Accident Rate, Fatal Crash Rate, Loss of Control Crash Rate were set as indexes of traffic safety evaluation. Also, reviews on the effectiveness of ESC were collected using keyword, 'ESC'. As a result, the Effect size of accident rate odd ratio was 0.90. When ESC system was applied on vehicles, accident rate decreased by 10%. Also, the Effect size of fatal crash rate odd ratio was 0.64. When ESC system was applied on vehicles, fatal crash rate decreased by 36%. Lastly, the Effect size of loss of control crash rate odd ratio was 0.73. When ESC system was applied on vehicles, loss of control crash rate decreased by 27%. The outcome of this study would be effectively used for developing polices and regulations for ESC installation obligation of commercial vehicles.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.4
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• pp.26-40
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• 2018

The aim of this research is to analyze factors affecting bicycle accidents using the PLS structural equation. Accident types in this study were categorized into total accidents, serious injuries including death, and light injuries which occurred at nationwide Si Gun Gu. It was found that urbanization was the main factor for bicycle accidents through the accident models developed in this study. Population, ratio of economically active population, density of intersections, ratio of urbanized area, commercial and industrial land-uses, number of drive license holders, number of education institutions, number of parks were the main factors causing bicycle accidents. Besides, length of bicycle roads, number of bicycles, and ratio of bicycle as mode choice also increased bicycle accidents.

• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.755-763
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• 2020

The critical flow phenomenon has been studied because of its significant effect for design basis accidents in nuclear power plants. Transition points from thermal non-equilibrium to equilibrium are different according to the geometric effect on the critical flow. This study evaluates the uncertainty parameters of the critical flow model for analysis of DBA (Design Basis Accident) with the MARS-KS (Multi-dimensional Analysis for Reactor Safety-KINS Standard) code used as an independent regulatory assessment. The uncertainty of the critical flow model is represented by three parameters including the thermal non-equilibrium factor, discharge coefficient, and length to diameter (L/D) ratio, and their ranges are determined using large-scale Marviken test data. The uncertainty range of the thermal non-equilibrium factor is updated by the MCDA (Model Calibration through Data Assimilation) method. The updated uncertainty range is confirmed using an LBLOCA (Large Break Loss of Coolant Accident) experiment in the LOFT (Loss of Fluid Test) facility. The uncertainty ranges are also used to calculate an LBLOCA of the APR (Advanced Power Reactor) 1400 NPP (Nuclear Power Plants), focusing on the effect of the PCT (Peak Cladding Temperature). The results reveal that break flow is strongly dependent on the degree of the thermal non-equilibrium state in a ruptured pipe with a small L/D ratio. Moreover, this study provides the method to handle the thermal non-equilibrium factor, discharge coefficient, and length to diameter (L/D) ratio in the system code.

• Korean journal of food and cookery science
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• v.28 no.4
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• pp.451-461
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• 2012

The purposes of this study were to examine the financial statements and analyze the financial soundness of contract foodservice management companies(CFMC) using the financial ratio. The statistical data analysis was completed using Microsoft Excel(ver.2007) for the trend line equation and using SPSS Win(ver.18.0) for wilcoxon-rank sum test. Increased asset, debt, capital and sales occurred in most of the CFMCs, but the financial trend of firm D decreased for operating profit and net profit. The financial ratio for investigating a firm's financial soundness was based on liquidity, stability, profitability, activity, and growth through financial statements. Most of the CFMCs had maintained outstanding financial soundness from 1999 to 2011. The financial statements during the decade were verified and fluctuated. The directly affected CFMCs by a school foodservice' sanitation accident had maintained better financial statements than those of other CFMCs. Therefore, there was opportunity for directly affecting CFMCs involved in school foodservice' sanitation accident to diversify the business portfolio of the firms.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.457-463
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• 2012

Changing the environment around detecting areas may lower the performance of a video-based accident detection system. Region of interest(ROI) and background information changing constantly on account of the car headlights at night and a sudden changes in the weather are the biggest factors to increase the ratio of wrong results. Thus, we proposed and implemented the integrated accident detection system combined the video-based system and the laser-based imaging system. In this paper, we were able to overcome the majority problem of video-based system and it was a meaningful results that it can improve the reliability for the system.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.3154-3165
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• 2022

During a loss-of-coolant accident (LOCA) in the pressurized water reactor (PWR), there is a possibility that high temperature and internal pressure of the fuel rods lead to ballooning of the cladding, which causes a partial blockage of flow area in a subchannel. Such flow blockage would influence the core coolant flow, thus affecting the core heat transfer during a reflooding phase and subsequent severe accident. However, most of the system analysis codes simulate the accident process based on the assumed channel blockage ratio, resulting in the fact that the simulation results are not consistent with the actual situation. This paper integrates the developed core Fuel Rod Thermal-Mechanical Behavior analysis (FRTMB) module into the self-developed severe accident analysis code ISAA. At the same time, the existing flow blockage model is improved to make it possible to simulate the change of flow distribution due to fuel rod deformation. Finally, the ISAA-FRTMB is used to simulate the QUENCH-LOCA-0 experiment to verify the correctness and effectiveness of the improved flow blockage model, and then the effect of clad ballooning on core heat transfer and subsequent parts of core degradation is analyzed.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1537-1546
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• 2017

Many thermal-hydraulic tests have been conducted at the Korea Atomic Energy Research Institute for verification of the SMART (System-integrated Modular Advanced ReacTor) design, the standard design approval of which was issued by the Korean regulatory body. In this paper, the contributions of these tests to the standard design approval of SMART are discussed. First, an integral effect test facility named VISTA-ITL (Experimental Verification by Integral Simulation of Transients and Accidents-Integral Test Loop) has been utilized to assess the TASS/SMR-S (Transient and Set-point Simulation/Small and Medium) safety analysis code and confirm its conservatism, to support standard design approval, and to construct a database for the SMART design optimization. In addition, many separate effect tests have been performed. The reactor internal flow test has been conducted using the SCOP (SMART COre flow distribution and Pressure drop test) facility to evaluate the reactor internal flow and pressure distributions. An ECC (Emergency Core Coolant) performance test has been carried out using the SWAT (SMART ECC Water Asymmetric Two-phase choking test) facility to evaluate the safety injection performance and to validate the thermal-hydraulic model used in the safety analysis code. The Freon CHF (Critical Heat Flux) test has been performed using the FTHEL (Freon Thermal Hydraulic Experimental Loop) facility to construct a database from the $5{\times}5$ rod bundle Freon CHF tests and to evaluate the DNBR (Departure from Nucleate Boiling Ratio) model in the safety analysis and core design codes. These test results were used for standard design approval of SMART to verify its design bases, design tools, and analysis methodology.

• Journal of Korean Society of Transportation
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• v.27 no.3
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• pp.141-148
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• 2009

An inappropriate evaluation of capacity leads to the incorrect and impractical result due to the transfer of error to the analysis and the evaluation on highway system. The traffic accident which reduces the capacity of road temporarily generates unpredictable congestion, causing difficulties in congestion management. Therefore, this research aims on the measurement of the capacity of the road in accordance to the speed at the accident which is a basic factor when performing analysis. Based on the given approach, the behavior of a vehicle in highway is understood to develop model of critical gap and model of maximum flow rate with respect to the speed of traffic flow. With the established model, the reduction rate of the capacity in highway system at the accident is measured. The result shows that the capacity is reduced by 37% when the speed of the traffic flow is 40km/h. Although the developed model can't be verified clearly, this research has shown that the reduction rate of the capacity in road system has a close relation to the speed.

• Journal of Korean Academy of Nursing
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• v.14 no.1
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• pp.1-20
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• 1984

This study was attempted to evaluate and explain the correlation between stress and utilization of Dispensary, Frequency of absence, Frequency of accident as the health condition of bluecollared workers. The subjects for this study were 260 workers selected conveniently from 360 workers working at one chemical manufacturer located in Seoul. The dataas measure the Stress was collected through SRRS (The Social Readjustment Rating Scale) which is developed by Holmes ＆ Rahe (1976) from 27th July to 10th August, 1983. The data of Utilization of Dispensary and Frequency of Accident were brought out from the record of Dispensary during past 8 months. The Frequency of Abscence from January to August were collected through diligence and indolence cards of each department. All collected data were analysed based on the SPSS (Statistical Package for the Social Science) program. The results of the study are as follows: 1. The average of Utilization of Dispensary was 7.4, Frequency of abscence 14.6, frequency of Accident 0.4. 2. The average score of Stress was 134 (minimum : 0, maximum : 593, Standard deviation : 109. 3) It can be considered as a slight stressed group by the requlations of Holmes and Rahe. 3. According to the analysed results of correlation between Stress and the Utilization of Dispensary, Frequency of Absence, frequency of Accident, the Utilization of dispensary and stress were significantly related (r= .1955, p<.001), the Frequency of Absence (r=.0284, p >, 05), and the Frequency of Absence (r=.0284, p>.05), and the Frequency of Accident (r= .0831, p>.05) were not significantly related with Stress. 4. In the relation between general characters of subjects and the Utilization of Dispensary, 20 to 25 aged group, women, single, christian, lent-house dwelling, 1 to 5 years employed group used at a high ratio. 5. In the relation between general character of subjects and the Frequency of Absence, men, 51 to 55 aged group, 21 to 25 years employed group indicated high Frequency, and other char-noters were not significantly related. 6. In the relation between general characters of subjects and the Frequency of Accident, women. single, 20 to 25 aged group, catholic, lent-house dwelling, below 1 year employed group showed high frequency. 7. Stress showed a significant difference only with a religion. Catholic group represented mode-rate stressed scored 209.67, and not significantly related with other general characters.

• Proceedings of the KOR-KST Conference
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• 1997.12a
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• pp.33-69
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• 1997

This study was conducted to develop a methodology to predict utility pole accident rates and to evaluate cost-effectiveness for safety improvement for utility pole accidents. The utility pole accident rate prediction model was based on the encroachment rate approach introduced in the Transportation Research Board Special Report 214. The utility pole accident rate on a section of highway depends on the roadside encroachment rate and the lateral extent of encroachment. The encroachment rate is influenced by the horizontal and vertical alignment of the highway as well as traffic volume and mean speed. The lateral extent of encroachment is affected by the horizontal and vertical alignment, the mean speed and the roadside slope. An analytical method to generate the probability distribution function for the lateral extent of encroachment was developed for six kinds of encroachment types by the horizontal alignment and encroachment direction. The encroachment rate was calibrated with the information on highway and roadside conditions and the utility pole accident records collected on the sections of 55mph speed limit of the State Trunk Highway 12 in Wisconsin. The encroachment rate on a tangent segment was calibrated as a function of traffic volume with the actual average utility pole accident rates by traffic volume strategies. The adjustment factors for horizontal and vertical alignment were then derived by comparing the actual average utility pole accident rates to the estimations from the model calibrated for tangent and level sections. A computerized benefit-cost analysis procedure was then developed as a means of evaluating alternative countermeasures. The program calculates the benefit-cost ratio and the percent of reduction of utility pole accidents resulting from the implementation of a safety improvement. This program can be used to develop safety improvement: alternatives for utility pole accidents when a predetermined performance level is specified.