• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.515-517
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• 2013

We carried out the maritime safety audit for Sandal Water Bridge constructed between Geje-Do and Sandal-Do in 2015. To study as to whether can be secured the marine traffic safety for this area, this research investigated and performed the marine accident, marine traffic volume, the marine traffic flow simulation and shiphandling simulation. It is considered to be required the quantitative guidelines for maritime safety audit including audit target area and formal audit object etc.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.6_spc
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• pp.729-735
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• 2016

According to the survey for working environment of the cashiers in highway tollbooths, workers replied that noise was the most harmful substances next to air pollutant in the tollbooth. Researches on the noise levels exposed to cashiers in the highway tollbooth scarcely have been performed. Therefore, the aim of this study was to acquire baseline data to prevent health impairments of the cashiers by evaluating noise level exposed to them. Noise dosimeters were used for monitoring workers' noise exposure level in the tollbooths at 8 different highway tollgates. The noise levels of tollbooths did not exceed noise exposure limit of the ministry of labor, 90 dB(A). The average TWA inside of the tollbooths was 55.4 dB(A) and the average TWA outside of tollbooths was 58.3 dB(A). The average TWA outside of tollbooths was slightly higher than that of inside of tollbooths. However, the significance probability(p-value) was 0.255 which means statistically not significant. The noise levels inside and outside of tollbooth were statistically significant to both mean traffic volume per day and traffic volume of passenger car.

• International Journal of Safety
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• v.11 no.1
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• pp.19-21
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• 2012

In this thesis, fracture test was performed in order to investigate the fracture strength of SFRC(steel fiber reinforced concrete) structures. The relationship between the compressive force and strain value of SFRC specimens were observed under the compressive strength test. From the fracture test results, the relationship between percentage of fiber by volume, compressive strength, elastic modulus, and tensile strength of SFRC beams were studied, and the measured elastic modulus of SFRC were compared with the calculated elastic modulus by ACI committee 544.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.573-577
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• 2012

Based on latest research, the parametric quality statistics cannot be used in non-normal process with demand pattern of many-variety and small-volume, since it involves extremely small sample size. The research proposes nonparametric quality statistics according to the number of lot or batch in the non-normal process. Additionally, the nonparametric Process Capability Index (PCI) is used with 14 identified non-normal distributions.

• Journal of the Korean Society of Safety
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• v.15 no.3
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• pp.52-56
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• 2000

The finite control volume method was utilized to investigate the effects of flow through openings on convection in an enclosure. Flow patterns and temperature distribution were compared for non-dimensional inflow velocity U=20, 40, 60 at Ra=$10^4$ and $5\times10^4$, respectively. The inflow velocity influenced temperature distribution in the enclosure significantly and lowered temperature on the top wall. The flow through openings forced the position of the highest temperature on the top wall to move toward the outflow opening.

• Journal of the Korean Society of Safety
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• v.37 no.2
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• pp.10-17
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• 2022

Currently, in Korea, lower and upper tier qualifying quantities of the 97 substances requiring preparation for accidents have been designated. The information on the submission of chemical accident prevention management plan varies depending on whether the handling volume is above or below the lower or upper qualifying quantity. Because the criteria of the lower and upper qualifying quantities of substance requiring preparation for accidents are not stipulated in the Chemical Substances Control Act, this study attempted to establish a criterion through significance verification. In addition, the study investigated whether these qualifying quantities are related to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), toxic concentration endpoint, and National Fire Protection Association (NFPA). Finally, by comparing the risk categorization of the GHS, endpoint, and NFPA, it was evaluated whether the circulation-volume-based risk categorization of the substance requiring preparation for accidents that are in the top 13 is appropriate. The qualifying quantities of benzene, toluene, and sulfuric acid needed to be adjusted upward, while those of methyl alcohol and ammonia were adjusted downward from the current qualifying quantities. It is required to establish a quantified criterion that fully reflects the domestic situations in Korea and various indicators such as toxicity, physicochemical properties, and circulation volume for the qualified criterion of hazardous chemical substances. The study is expected to be helpful in establishing an efficient system by systematizing the criterion for qualifying quantity.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.9-13
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• 2010

An experimental study for characteristics of soot were conducted at the post-flame region in jet diffusion flames, where carbon dioxide was used as additives in oxidizer stream. Light-extinction method was performed using He-Ne laser with wave length at 632.8nm for the measurement of relative soot density and soot volume fraction with dimensionless extinction coefficient, $K_e$ and mass specific extinction coefficient, ${\sigma}_s$. To increase of resolution, laser light was modified for sheet-form using concave, convex lenses and slit. C/H ratio was introduced for quantitative analysis of soot growth which is expressed by carbonization and dehydrogen. Also transmission electron microscopy(TEM) was used for observation of morphological shape. The results show that the relative soot density in the post-flame region was lower when carbon dioxide was added in oxidizer stream because of reduction of flame temperature.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.2
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• pp.21-31
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• 2015

The world air transport industry has grown steadily with quantitative expansion. The volume of air transport in the world is skyrocketing with the open-sky trend. Air passengers from or to South Korea has shown 5% of annual growth for the last couple of decades which caused South Korea now ranking in 18th in the World for air transport market size. Quantitative expansion of Air transport affects in policy making of air transport operators, such as airports, airlines or authorities, directly and indirectly. Especially, Aviation Safety field should be supported by policy regime with the growth of air transport volume, assured resources for continuous monitoring is standing out as a vital factor. This study is to estimate social costs caused by aviation accidents and investment costs for aviation safety by airports, airlines and authorities as operators. Estimated investment costs for aviation safety verified by comparing and analysing them. Precedent studies were reviewed to refer research methodology to calculate aviation accident costs and safety costs of operators. Safety costs of operators was calculated with literature researches and interview surveys among professionals of each operators in rational range.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.87-95
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• 2019

Earth-work calculation is the important data for estimating the optimal construction cost at the construction site. Earth-work calculations require the accurate terrain data and precise soil volume calculations. Drone surveying technology provides accurate topography in a short time and economic advantages. In this paper, a drone surveying technique was used to derive a high precision soil volume calculation system. Field demonstration were performed to verify the accuracy of the volume measurement system. The results of earth-work calculation using drone survey were compared with those of GPS surveying. In addition, the developed earth-work volume calculation algorithm is compared with the existing aerial survey software (Pix4D) to verify the accuracy.

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.81-88
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• 1996

In order to investigate the electrical properties of transformer oils for large power, the characteristics of AC and Impulse breakdown in gap length of 1.0~2.5mm and that of volume resistivity were researched in temperature range of 20~$100^{\circ}C$. An geometrical capacitance of electrode with coaxial cylindrical shape for measuring the volume resistivity was 16pF, and highmegohm meter with model no. VMG-1000 was used, and also the applied voltage were DC 100, 250 and 500V. In the dependance of breakdown characteristics due to electrode gap length, it was confirmed that breakdown voltage was nearly uniform by volume effect according to the increase of gap. In the characteristics for AC breakdown, the dielectric strength was increased to $90^{\circ}C$ but decreased over $90^{\circ}C$, and also in case of impulse breakdown, it was increased to 7$0^{\circ}C$ and at dated $70^{\circ}C$ over in temperature range. The calculated mobility of oils in the characteristics for impulse breakdown were about $10^{-5}$~$10^{-4}cm^2/V{\cdot}S$, and the value of volume resistivity was almost invariable in low temperature range, regardless of voltage by the stable thermal properties, and it indicated a peak at $50^{\circ}C$ and had a sudden change to decrease over that temperature, and also the value of volume resistivity in 250V/mm at $80^{\circ}C$ is suitable for the International electrical standards, it was confirmed.