• Journal of the Korean Institute of Gas
• /
• v.12 no.2
• /
• pp.48-52
• /
• 2008

According to extremely industrial growth, gas facilities, equipments and chemical plants are gradually increased due to incremental demands of annual amount of gases. The safety management of gases, however, is still far from their requirements. Methane, the principal ingredient of natural gas, is inflammable and explosive and is much used in factories and houses. Therefore, these gas safety management is essential. So, we, with a program of the gas safety management, hope to develop the detection system of methane gas leak using mid-infrared ray LED and PD with $3.2\;{\mu}m$. The cryogenic cooling device is indispensible at laser but needless at LED driven on the room temperature if manufacturing optical sensor with $3.2\;{\mu}m$. It, consequently, is not only possible to implement for subminiature and portable type but also able to speedily detect methane of extremely small quantities because the $CH_4$ absorption intensity at $3.2\;{\mu}m$ is stronger than that at $1.67\;{\mu}m$. Our objective of research is to prevent gas leak accidents from occurring previously and to minimize the extent of damage from them.

• Korean Journal of Remote Sensing
• /
• v.35 no.6_2
• /
• pp.1083-1093
• /
• 2019

The purpose of this study is to detect the burned area change by direct burning of tree canopies and post-fire mortality of trees via analyzing satellite imageries from the Korea multi-purpose satellite-2 and -3 (KOMPSAT-2 and -3) for two large-fires over the Goseong-Sokcho and Gangneung-Donghae regions in April 2019. For each case, the burned area was compared between two dates: the day when the fire occurred and 15-18 days after it. As the results, within these two dates, there was no substantial difference in burned area of sites whose severities were marked as "Extreme", but sites with "High" and "Low" severities showed significant differences in burned area between the two dates. These differences were resulted from the lagged post-fire browning of canopies which was detected by images from in-situ observation,satellite, and the unmanned aerial vehicle. The post-fire browning started after 3-4 days and became apparent after 10-15 days. This study offers information about the timing to quantify the burned area by large fire and about the mechanism of post-fire mortality. Also, the findings can support policy makers in planning the restoration of the damaged areas.

• Korean Security Journal
• /
• no.42
• /
• pp.205-227
• /
• 2015

The Korean Peninsula is put in a position to carry out a highly strategic game vis-a-vis nK, which is asserting itself as a nuclear power amongst Northeast Asia's complex dynamics. While the international community recognizes nK's possession of nuclear weapons as released secret based on nK's three nuclear tests, shrewd strategic thinking is needed by ROK to secure itself as a non-nuclear nation in order to assume a responsible role to the international community, while simultaneously being ready to respond at all times for nK's military provocations. ROK must continue with its twofold strategy, by firm response to military confrontation with nK and maintaining flexible policy of tolerance in the areas of economy and ethnicity. Various strategic options to overcome nK's nuclear threats have been presented to ROK, whose possession of nuclear weapons have been difficult, and nK's nuclear capability is a real threat to ROK's national security. We must be able to respond to nK's nuclear threats strictly from ROK's national security perspective. This thesis aims to propose a response policy for nK's nuclear capability and nK's nuclear attack based on analysis of such nuclear damage, ROK Government's response posture against nK's nuclear threats, centered around ROK Government's non-military response posture.

• Tunnel and Underground Space
• /
• v.17 no.2 s.67
• /
• pp.128-138
• /
• 2007

At low in-situ stress, the continuity and distribution of natural fractures in rock mass predominantly control the failure processes. However at high in-situ stress, the failure process are affected and eventually dominated by stress-induced fractures preferentially growing parallel to the excavation boundary. This fracturing is often observed in brittle type of failure such as slabbing or spatting. Recent studies on the stress- or excavation-induced damage of rock revealed its importance especially in a highly stressed regime. In order to evaluate the brittle failure around a deep underground opening, physical model experiments were carried out. For the experiments a new tue triaxial testing system was made. According to visual observation and acoustic emission detection, brittle failure grades were classified under three categories. The test results indicate that where higher horizontal stress, acting perpendicular $(S_{H2})$ and parallel $(S_{H1})$ to the axis of the tunnel respectively, were applied, the failure grade at a constant vertical stress level (Sy) was lowered. The failure initiation stress was also increased with the increasing $S_{H1}\;and\;S_{H2}$. From the multi-variable regression on failure initiation stress and true triaxial stress conditions, $f(S_v,\;S_{H1},\;S_{H2})$ was proposed.

• Toxicological Research
• /
• v.14 no.4
• /
• pp.515-523
• /
• 1998

Oxidative stress by reactive oxygen species (ROS) damages cellular DNA, RNA, proteins, lipids and others causing various diseases such as cancer, arthritis, and heart diseases. 8-Hydroxyguanine (8-OHG) is one of the products formed from DNA or RNA damaged by ROS. Since high amounts of 8-OHG can be excreted in urine, it may serve as a potential biomarker indicating the level of oxidative damage to nucleic acids. Residents in industrial area with severe air pollution are expected to be affected by higher level of oxidative stress from pollutants like polyaromatic hydrocarbons (PAHs), etc. Smokers are also expected to be damaged by higher level of oxidative stress from cigarette smoke components like PAHs than non-smokers. To examine if the determination of the urinary concentration of 8-OHG could be used as exposure biomarker for the oxidative stress caused by air-pollutants, this study was performed to determine and compare the urinary concentrations of 8-OHG in smokers and non-smokers, or non-polluted area residents and polluted area residents. Urine samples were collected and purified by a strong cation exchange and cellulose partition column, then analyzed by HPLC with electrochemical detector at 600 ㎷ potential. Concentrations of urinary 8-OHG in non-smokers and smokers of Seoul area college male students were determined as 15.12$\pm$9.68 (ng/mg creatinine) and 34.72$\pm$11.72 (ng/mg creatinine), respectively, showing significantly higher level of 8-OHG in smokers than in non-smokers. Urine samples of elementary school students were collected from Sokcho area, which is known to be non-polluted, and 3 representative polluted areas; Yocheon industrial area, Ulsan urban and Ulsan industrial area. The concentrations of 8-OHG in these samples were 12.42$\pm$8.27 (ng/ mg creatinine, Sokcho), 22.55$\pm$9.12 (ng/mg creatinine, Yocheon), 17.41$\pm$2.30 (ng/mg creatinine, Ulsan urban), 55.04$\pm$39.73 (ng/mg creatinine, Ulsan industrial). Thus, samples from polluted area tend to have higher level of 8-OHG and the levels of Yocheon and Ulsan industrial area were significantly higher than that of Sokcho area. The results indicate that the residents of polluted industrial area or smokers are more severely exposed to oxidative stress probably caused by air pollutants like PAHs. Thus, the determination of urinary 8-OHG concentration could be used as biomarker for the extent of body exposure to oxidative stress caused by various pollutants.

• Journal of Yeungnam Medical Science
• /
• v.12 no.1
• /
• pp.48-55
• /
• 1995

The present study was designed to evaluate the efficiency of total lactate dehydrogenase, total creatine kinase, LD1/LD2 ratio, CK-MB and newly developed troponin T in acute myocardial infarction. The level of troponin T was $0.01{\pm}0.02{\mu}g/L$ in 34 healthy person, but the peak vaule of acute myocardial infarction ranged in 4.7-24.2 ${\mu}g/L$. Total lactate dehydrogenase was peaked in 1 to 3 days after chest pain and then progressively decreased, but LD1/LD2 ratio was persistently higher than 1.0 for 10 days in most patients. Total creatine kinase and CK-MB were peaked in 1-2 days, and normalized in 3-4 days, so they were useful in early diagnosis of acute myocardial infarction, but not for the late stages of acute myocardial infarction. Troponin T is early elevated and persistently high level for more than 10 days. Comparing with total lactate dehydrogenase, total creatine kinase, LD1/LD2 ratio and CK-MB, troponin-T test improves the efficiency of serodiagnostic method for the detection of ischemic myocardial damage.

• Journal of Korea Water Resources Association
• /
• v.54 no.12
• /
• pp.1233-1242
• /
• 2021

In this study, a model was developed to determine whether flooding occurred using image data, which is unstructured data. CNN-based VGG16 and VGG19 were used to develop the flood classification model. In order to develop a model, images of flooded and non-flooded images were collected using web crawling method. Since the data collected using the web crawling method contains noise data, data irrelevant to this study was primarily deleted, and secondly, the image size was changed to 224×224 for model application. In addition, image augmentation was performed by changing the angle of the image for diversity of image. Finally, learning was performed using 2,500 images of flooding and 2,500 images of non-flooding. As a result of model evaluation, the average classification performance of the model was found to be 97%. In the future, if the model developed through the results of this study is mounted on the CCTV control center system, it is judged that the respons against flood damage can be done quickly.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.4
• /
• pp.28-36
• /
• 2021

It is known that buried rebars inside concrete structures are protected from corrosion due to passive layer. It is very important to delay the timing of corrosion or evaluate a detection of corrosion initiation for the purpose of cost-beneficiary service life of a structure. In this study, corrosion monitoring was performed on concrete specimens considering 3 levels of cover depth(60 mm, 45 mm, and 30 mm), W/C(water to cement) ratio(40.0%, 50.0%, and 60.0%) and chloride concentration(0.0%, 3.5%, and 7.0%). OCP(Open Circuit Potential) was measured using agar-based socket type sensors. The OCP measurement showed the consistent behavior where the potential was reduced in wet conditions and it was partially recovered in dry conditions. In the case of 30 mm of cover depth for most W/C ratio cases, the lowest OCP value was measured and rapid OCP recovery was evaluated in increasing cover depth from 30 mm to 45 mm, since cover depth was an effective protection against chloride ion ingress. As the chloride concentration increased, the effect on the cover depth tended to be more dominant than the that of W/C ratio. After additional monitoring and physical evaluation of chloride concentration after specimen dismantling, the proposed system can be improved with increasing reliability of the corrosion monitoring.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2019.04a
• /
• pp.54-54
• /
• 2019

Apple (Malus domestica) is one of the most economically important fruits in Korea. But virus infection has decreased sustainable production of apple and caused the serious problems such as yield loss and poor fruit quality. Virus or viroid infection including Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), Apple mosaic virus (ApMV) and Apple scar skin viroid (ASSVd) has been also reported in Korea. In many cases, apple is infected with virus and viroid with no specific symptoms, the damage caused by the virus are unaware significantly. In our research, we tried to eliminate viruses in the rootstock for the disease-free seedlings of the apple dwarfing rootstock M.9 and M.26. The method of virus elimination was meristem culture, heat($37^{\circ}C$, 6weeks) treatment and chemistry($Ribavirin^{(R)}$) treatment. The analytical methods commonly used for the detection of virus is Enzyme-linked Immuno-Sorbent Assay(ELlSA) and Reverse Transcription-polymerase Chain Reaction(RT-PCR). RT-PCR method was more 30% sensitive than ELISA method. Efficiency of method eliminate virus appeared meristem method > heat treatment > chemistry treatment. The higher acquisition rate of disease-free seedlings is 30~40% on meristem treatment. In meristem treatment, the apple dwarfing rootstock M.9 gained infection ratio of ACLSV, ASPV and ASGV were 45%, 60% and 50% respectively. In the apple dwarfing rootstock M.26, infection ratio of ACLSV, ASPV and ASGV were 40%, 55%, 55%, respectively. Based on our results, it was found that most effective method of disease-free seedlings apple dwarfing rootstocks was by meristem treatment than heat method and chemistry treatment.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.5
• /
• pp.550-559
• /
• 2019

The sinking of the M/V SEWOL in April 2014 was not a mere marine accident, but a marine catastrophe. This grim case developed into a social tragedy that impinged the national sentiment and communal integrity. It is imperative that thorough provisions and measures be outlined at the national level with regard to massive marine accidents, oil pollution, and natural disasters that might critically affect government affairs. Pivoting on "The Black Swan Theory," a concept of improperly rationalizing a national crisis based on uncertainties, this research assesses a variety of response strategies that minimize the national economic and social damage caused by a large-scale marine disaster. Along with the effort of minimizing any potential defects in each protective barrier, the "Black Swan Detection System of the Marine Disaster" needs to be incorporated to prevent cases wherein such defects lead to an actual crisis. Maritime safety must be systematically unified under a supervisory organization, and a structure for maritime crisis on-scene command and cooperation must likewise be established in order that every force on the scene of a marine disaster may act effectively and consistently under the direction of an on-scene commander.