• Composites Research
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• v.21 no.4
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• pp.1-6
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• 2008

This paper explains fire safety tests of a hybrid composite train carbody with carbon/epoxy sandwich bodyshell and stainless steel underframe. In this study, a large scale mock-up was used to evaluate the fire safety of the composite train carbody. The test was conducted to the bare composite carbody mock-up without interior facilities and the fully equipped one. Tile fire propagation and temperature distribution of the carbon/epoxy bodyshell and the glass phenol interior panels was evaluated under the real fire accident scenario. The test scenario was based on the DaeGu subway fire accident. From the tests, both the surface temperature of the interiors and the composite bodyshell wore lower than tile ignition temperature. In addition, the fire spread along the surface of the interiors and bodyshell was not occurred.

• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.31-42
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• 2004

This study develops Accident Modification Factors (AMF) of countermeasures with Baysian method which are newly proposed for reducing Roadway-Rail grade crossing accidents. This study proposes a new "Bayesian Analytical Framework" for countermeasure assessment which combines "Subjective" Prior Information with "Logical" based Information. The newly proposed "Bayesian Analytical Framework" consists of the following three steps: The 1st step - Countermeasure Selection, Choice of Participants, Selection of Crashes; The 2nd step-Development of Crash History Manual and Countermeasure Evaluation Manual; The 3rd step-Development of AMFs through sound statistical tests. This study used the Komogorov-Smirnov(K-S) Test to determine whether two unknown distribution functions associated with the two populations are identical. The results of the study are that individual responses did not meet the K-S test of identical distributions. while individual vs. group distributions are identical. This indicates that combining the input of several people reduces the impact of individual subjectivity and assumptions and is important for developing a repeatable distribution to develop sound AMFs of countermeasures for reducing Roadway-Rail grade crossing accidents. The procedures of the AMF development conducted in this study can be used to estimate the safety effects of countermeasures for road segments and intersections, in addition to Roadway-Rail grade crossings.

• Journal of Korean Medicine Rehabilitation
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• v.18 no.3
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• pp.99-118
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• 2008

Objectives : This study aimed to understand the satisfaction degree of patients due to traffic accident(TA) in order to provide basic data which would give help not only to improve the quality of services, but also to strengthen the competitiveness of oriental medical hospitals on sequela of TA patients. Methods : The data were collected from inpatients and outpatients who answered a self-report questionnaire. Independent t-test, analysis of variance(ANOVA), $X^2$-test, correlation analysis were used for data analysis. Results : According to the research on medical satisfaction degree, the overall satisfaction degree was 4.141. On each field, satisfaction degree related to the doctor service recorded the highest degree among others(4.474). Satisfaction degree related to the appropriateness of service was the second(4.091). On the other hand, satisfaction degree of using procedure was the lowest degree(3.857). On the difference of degrees of satisfaction by general characteristics, patients who were unemployed houseworker group showed lower doctor service satisfaction degree than that of other groups. However, on the difference of degrees of satisfaction related to other general characteristics, there were no significant differences(p<0.05). Conclusions : The service distribution of oriental medical hospital was almost equal without concentrating on specified social classes.

• Nuclear Engineering and Technology
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• v.29 no.2
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• pp.110-126
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• 1997

A two-dimensional continuum model for the hydrogen mining phenomena in the containment subcompartment under severe accident conditions has been developed to predict the spatial distribution of the hydrogen concentration. The model can predict the distribution of time-dependent hydrogen concentration for HEDL experiments well. For the simulation of these experiments, the hydrogen is mixed uniform within the test compartment. To predict the extent of non-uniform distribution, the dominant factors such as the geometrical shape of obstacle and velocity of source injection in mixing phenomena are investigated. If the obstacle disturbing the flow of gas mixture exists in the compartment, the uniform distribution of hydrogen might be not guaranteed. The convective circulation of gas flow is separately formed up and down of the obstacle position, which makes a difference of hydrogen concentration between the upper and lower region of the compartment. The recirculation flow must have a considerable mass flow rate relative to velocity of the source injection to sustain the well-mixed conditions of hydrogen. Finally, in order to account for non-uniform distribution of the hydrogen due to the geometrical configuration the maximum-to-average ratio is functionalized.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.123-128
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• 2021

As the spread of DC power distribution systems increases, the occurrence of failures and fire accidents are also increasing. In particular, the ESS fire accident, which is a component of the smart grid, and the fire accident of the solar power system, which is a direct current system, are caused by problems in the electrical connection between system components as the supply of new and renewable energy rapidly increases and old facilities increase. An arc that can cause a direct fire by releasing the induced light and heat has been pointed out as one of the causes of fire. Therefore, the problem of such an arc defect is that it is impossible to block an arc accident in advance with the existing overcurrent circuit breaker and earth leakage circuit breaker. In this paper, we intend to develop a test equipment that satisfies international standardization and to develop a DC arc generator to protect against failure and fire caused by arcing.

• Nuclear Engineering and Technology
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• v.33 no.3
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• pp.315-326
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• 2001

Direct ECC bypass phenomena that occur in a reactor vessel downcomer with a Direct Vessel Injection (DVI) system during the reflood phase of a Large Break Loss-of-Coolant Accident (LBLOCA) are experimentally investigated using a transparent l/7.5 scaled down test facility of the Upper Plenum Test Facility (UPTF). A series of separate effect tests are peformed in order to investigate the mechanisms of direct ECC bypass and to find out its scaling parameters. Various flow regimes and phasic distribution in downcomer are identified and mapped, and the fraction of direct ECC bypass is measured under a wide range of air and water injection conditions. From the counterpart test of the UPTF Test 21-D, the dimensionless gas velocity ( $j^{*}$$_{g,eff}$) is derived experimentally, which is believed to be a major scaling parameter for the fraction of direct ECC bypass. And it is found out that the direct ECC bypass is greatly affected by the spreading width of ECC water film and the geometric configuration of the downcomer.r.

• Tribology and Lubricants
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• v.33 no.2
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• pp.45-51
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• 2017

Engine oil is a substance used for the lubrication of internal combustion systems. However, in some case, defects in engine systems may contaminate engine oil with fuel. Contaminated engine oil can cause problems in the normal functioning of a vehicle. In this study, we investigate the functional properties of engine oil contaminated with diesel fuel. The test results indicate that the engine oil contaminated with diesel fuel has low flash point, pour point, density, kinematic viscosity and cold cranking simulator value. The contaminated engine oil which has low plash point can cause fire and explosion accident. Furthermore, a four ball test indicates that the contaminated engine oil increases wear scar to poor lubricity. Moreover, we investigate the GC pattern using SIMDIST (simulated distillation) for determination of diesel in engine oil. The SIMDIST analytic result, diesel was detected at earlier retention time than engine oil in chromatogram. Thus the SIMDIST method can define whether engine oil is contaminated by diesel fuel or not. We can use the SIMDIST method for the diagnosis of oil condition instead of analyzing other physical properties that require many analytic instruments, large volume of oil sample and long analysis time.

• Journal of the Korean Society of Safety
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• v.25 no.4
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• pp.7-12
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• 2010

The average growth in the wind power energy market during the past five years has been 26% per year. Renewable energy resources, of which wind energy is prominent, are part of the solution to the global energy problem. Wind power system and the rotor blade concepts are reviewed, and loadings by wind and gravity as important factors for the mechanical performance of the materials are considered. So, the mechanical properties of fiber composite materials are discussed. In addition, it is necessary to analyze and evaluate the stress distribution and deformation for them in the design level. This study shows the result that CFRP rotor blade of wind turbine satisfies the strength and deformation through numerical analysis using the commercial finite element analysis program.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.187-190
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• 1999

To reduce the maintenance expence, and the possibility of electric outage and accident, accurate measurement should be carried. But the classical method has some problems in the aspect of man power, reliability, and expence. In this paper, we propose a new type apparatus, which could detect the degree of contamination on insulators on outdoor insulation system, such as transmission and distribution line insulator and bushing. The new type apparatus consists of Pelltier module, electrode system, and measuring part. At first leakage current detecting method was considered, then with the fault(oxidation of electrode) of that method we should propose a another method. We carried various test to prove the possiblity and reliability of the propoused apparatus. And we get some useful result with laboratory test.

• Journal of Navigation and Port Research
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• v.43 no.1
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• pp.1-8
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• 2019

Identifying behavioral errors of seafarers that have led to marine accidents is a basis for research into prevention or mitigation of marine accidents. The purpose of this study is to estimate the optimal probability distribution function needed to model behavioral errors of crew members into three behaviors (i.e., Skill-, Rule-, Knowledge-based). Through use of behavioral data obtained from previous accidents, we estimated the optimal probability distribution function for the three behavioral errors and verified the significance between the probability values derived from the probability distribution function. Maximum Likelihood Estimation (MLE) was applied to the probability distribution function estimation and variance analysis (ANOVA) used for the significance test. The obtained experimental results show that the probability distribution function with the smallest error can be estimated for each of the three behavioral errors for eight types of marine accidents. The statistical significance of the three behavioral errors for eight types of marine accidents calculated using the probability distribution function was observed. In addition, behavioral errors were also found to significantly affect marine accidents. The results of this study can be applied to predicting marine accidents caused by behavioral errors.