• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.760-768
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• 2017

The transition temperature shift (TTS) of the reactor pressure vessel materials is an important factor that determines the lifetime of a nuclear power plant. The prediction of the TTS at the end of a plant's lifespan is calculated based on the equation of Regulatory Guide 1.99 revision 2 (RG1.99/2) from the US. The fluence factor in the equation was expressed as a power function, and the exponent value was determined by the early surveillance data in the US. Recently, an advanced approach to estimate the TTS was proposed in various countries for nuclear power plants, and Korea is considering the development of a new TTS model. In this study, the TTS trend of the Korean surveillance test results was analyzed using a nonlinear regression model and a mixed-effect model based on the power function. The nonlinear regression model yielded a similar exponent as the power function in the fluence compared with RG1.99/2. The mixed-effect model had a higher value of the exponent and showed superior goodness of fit compared with the nonlinear regression model. Compared with RG1.99/2 and RG1.99/3, the mixed-effect model provided a more accurate prediction of the TTS.

• The Journal of Korean Medicine
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• v.33 no.3
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• pp.95-104
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• 2012

Objectives: There are some controversies over the safety of herbal medication in relation to liver function. This report, therefore, aimed to analyze the safety issue of herbal medications by scrutinizing the liver function tests (LFT) results of 82 psoriasis patients on herbal medications for 3 months at an oriental medical clinic. Methods: We tested psoriasis patients' liver function periodically with Reflotron Plus of Roche during the herbal medication. Then we statistically analyzed the LFT results to see if there was any negative change. Results: Statistical analysis on the LFT results of 82 psoriasis patients showed no meaningful change caused by herbal medication over 3 months. Conclusions: From this result we conclude that herbal medication for 3 months does no harm to patients' liver function.

• Journal of the Korean Institute of Gas
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• v.10 no.3 s.32
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• pp.54-59
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• 2006

A safety device with shut-off function was developed for preventing intentional accidents that might happen by separating of cutting hoses connected to pressure regulators used in residential LP gas facility. For the verification of function and field adaptability, the safety device with shut-off function was tested in the state of joining the device to the regulator and a field test was carried out at home. This study shows that, at the inlet pressure of 0.07-1.56 MPa, the device shuts off the gas within the 5m length of hose regardless of the installation condition of the regulator. The shut-off flow rate increases in the order of perpendicular upward, horizontal and perpendicular downward. From the results of the field tests carried out at home for 5 months, there appears no problem using a gas range or a boiler. If the developed shut-off device is commercialized and distributed in the market the intentional accidents occurred by cutting or separating hoses can be prevented remarkably.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.2
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• pp.148-155
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• 2024

Objectives: Among the regulations that have recently attracted a lot of social attention in Regulation on Occupational Safety and Health Standards, we would like to specifically present the reasons why even companies with strong will to comply with regulations that are not effective or entail a number of legal problems, and suggest ways to improve them. Methods: The facts were confirmed and identified through various methods such as interviews and meetings with labor inspectors who enforce the Regulation on Occupational Safety and Health Standards and safety officials at industrial sites experiencing them. Results: Due to the lack of effectiveness in Regulation on Occupational Safety and Health Standards, there are not a few areas that do not function properly as a preventive standard. Although operating the regulatory nature of punishment as an administrative guideline without basing it on Regulation on Occupational Safety and Health Standards is a direct violation of the principles of the administration of the rule of law, there are many expedient ways to replace what should be placed in this rule as just an administrative guideline. Conclusions: It should be prioritized to explicitly stipulate effective regulations within the Regulation on Occupational Safety and Health Standards. In addition, as regulations on occupational safety and health standards play a large part in preventing industrial accidents, comprehensive and practical measures are indispensable rather than fragmented and formal measures to ensure that these rules function properly in the prevention industrial accidents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.574-582
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• 2018

In systems such as railways, automobiles, and airplanes, system malfunctions may lead to accidents, which often cause serious personal injury and economic loss. In previous studies, failure analysis has been performed, and safety measures derived using the component level information to reduce damage when a failure occurs. However, in functional safety concept, a focus is placed on lowering the frequency of occurrence of failures by performing risks analysis, setting up safety goals, and designing safety functions. Therefore, it is necessary to study how to determine the required safety function that can reduce the failure frequency to the acceptable level. To achieve this, we first studied a failure modeling method using SysML. It was then presented how several alternatives can be assessed to determine the desired safety function by simulating the generated SysML failure models and calculating the ability to reduce the failure frequency. A case study of a railway signaling system was done, demonstrating the effectiveness of the approach. We assessed whether the safety objectives were met for the alternative design of the railway signaling system through M & S. The results can be useful in that it can be applied from the early design phase and allow to choose the appropriate safety function that satisfies safety objectives among various design alternatives.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.203-213
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• 2021

A vehicle crash occurs due to various factors such as the geometry of the road section, traffic, and driver characteristics. A safety performance function has been used in many studies to estimate the relationship between vehicle crash and road factors statistically. And depends on the purpose of the analysis, various characteristic variables have been used. And various characteristic variables have been used in the studies depending on the purpose of analysis. The existing domestic studies generally reflect the average characteristics of the sections by quantifying the traffic volume in macro aggregate units such as the ADT, but this has a limitation that it cannot reflect the real-time changing traffic characteristics. Therefore, the need for research on effective aggregation units that can flexibly reflect the characteristics of the traffic environment arises. In this paper, we develop a safety performance function that can reflect the traffic characteristics in detail with an aggregate unit for one hour in addition to the daily model used in the previous studies. As part of the present study, we also perform a comparison and evaluation between models. The safety performance function for daily and hourly units is developed using a negative binomial regression model with the number of accidents as a dependent variable. In addition, the optimal negative binomial regression model for each of the hourly and daily models was selected, and their prediction performances were compared. The model and evaluation results presented in this paper can be used to determine the risk factors for accidents in the highway section considering the dynamic characteristics. In addition, the model and evaluation results can also be used as the basis for evaluating the availability and transferability of the hourly model.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.6
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• pp.1390-1396
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• 2008

The aim of this study is to analyze literatures researching changes of liver function parameters after administration of herbal medicine and the safety of herbal medicine on hepato-biliary system. Eight Korean databases were searched for researches on the safety of oriental herbal medicine. According to inclusion criteria, nineteen studies were selected and analyzed. As a result, seventy outcomes in five parameters(aspartate transaminase, alanine transaminase, gamma(${\gamma}$)-glutamyl transferase, alkaline Phosphatase, total bilirubin) were obtained. After administration, parameters decreased or sustained in fifty seven outcomes. In thirteen outcomes, parameters slightly increased. In two outcomes, parameters increased but not severely. The change of liver function parameters after administration of herbal medicine is expected to be harmless. But it requires additional large scale studies and modification in method to corroborate the safety of herbal medicine.

• KSBB Journal
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• v.22 no.5
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• pp.318-321
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• 2007

Photodynamic therapy (PDT) is a targeted-tumor treatment system using a photosensitizer, light and oxygen to treat malignant tumor. We have investigated the cytotoxicity of 4 types of phthalocyanine derivative (silver phthalocyanine, iron (III) phthalocyanine, copper (II) phthalocyanine, nickel (II) phthalocyanine) against lung and breast cancers based on photodynamic therapy. As a result, phthalocyanine derivatives indicated a higher anticancer activity on a breast cancer cell line. Among the tested phthalocyanines, silver phthalocyanine (AgPc) showed a lower cytotoxicity against a normal cell line. In addition AgPc gave a good color characteristic when it is solubilized in water. Finally AgPc was selected as a potential antitumor agent for breast cancer.

• Journal of Korean Society of Transportation
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• v.33 no.1
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• pp.81-89
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• 2015

Crashes that occur at tollgates have different characteristics compared to those of the mainline on expressways in terms of crash cause, crash type, and vehicle type. Due to this fact, the safety performance function (SPF) focused on the expressway tollgates, apart from the mainline, should be developed. The aim of this study is, therefore, to identify the influential factors and develope a SPF for crashes at tollgates. Firstly, we established independent variables affecting crashes at tollgates through literature review and descriptive statistical analysis. Based on these variables, two negative binomial regression models with different form of independent variables were developed and goodness-of-fits of each model were compared. According to the results, the number of crashes increases i) as AADT, Hi-pass rate, and heavy vehicle rate increase, ii) as average lane width decreases, iii) on the mainline tollgate type. The safety performance function developed in this study could be applied to select hot-spots for expressway tollgates.

• KSBB Journal
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• v.26 no.2
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• pp.165-171
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• 2011

Fractional solvent extraction by organic solvents such as hexane, chloroform, ethylacetate, and butanol was carried out using 70% ethanol extract of apple flower leaves. Biological activities including antioxidant, whitening, antimicrobial and anti-wrinkle activities were investigated and bio-active materials of the extracts were identified using GC/MSD. Among the tested solvent fractions, ethylacetate fraction showed the highest total polyphenol content (1218.94 ${\mu}g/mL$), and flavonoid (140 ${\mu}g/mL$). The DPPH radical scavenging activities was over 80% at a dry matterbased concentration of 200 ${\mu}g/{\mu}L$ and SOD-like activity was over 90% at 50 ${\mu}g/mL$ concentration in ethylacetate fraction that was slightly lower than of ascorbic aicd. Tyrosinase inhibition activity related to skin-whitening was over 60% by ethylacetate fraction of 100 ${\mu}g/mL$. As an anti-aging effect, elastase inhibitory activity was about 45% in ethylacetate fraction. Also, it showed a significantly antimicrobial activity against P. acenes. From GC/MSD analysis, a characteristic peak of high content in ethylacetate fraction was identified as kaempferol, which has been reported as a bioactive compound.