• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.202-207
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• 2016

An auxiliary real-time train communications system among drivers, train-traffic controllers and field workers is necessary to share hazard information (i.e. rockfall detection, track maintenance) in low visibility zones (long tunnels and steep curved track). To develop the appropriate communication system, this paper proposes a new way of power line communication using the rail track (Rail - PLC), which has little noise and distortion of attenuation. Therefore, it is important to measure the impedance of the rail and to apply an impedance matching technique to increase the transmission characteristic of the Rail - PLC. This study would evaluate the reflection and the transmission characteristics of the rail using a network analyzer and an impedance matching transformer. The suitable impedance matching ratio was 1:3.28 from the result of back-to-back testing. The results confirmed that the transformer can improve the performance of the transmission signal in Rail - PLC using an impedance matching technique.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.3
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• pp.270-278
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• 2014

This paper describes an improvement of space objects orbit prediction. To screen possible collisions between operational satellites and space objects, the TLE (Two-Line Element) was used as pseudo-measurement and than the orbit determination and orbit prediction were performed through the flight dynamics system. For determining the orbits, the state vectors were assumed by a series of TLEs within a certain period. The propagation error was analyzed according to the fitting period and a number of pseudo-observations. In order to find out the improvement of orbit prediction with the proposed method, KOMPSAT-2, 3 having the precise orbit in the meter-level range were first applied. Then the result applied to space objects under the same conditions was analyzed. As a result of the RMS error comparison with the orbit prediction of space object, the precision of orbit prediction was improved by approximately 90% for seven days prediction. The improved orbit prediction of space objects can be utilized in the daily analysis for initial screening of the close space objects at high risk.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.7
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• pp.550-557
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• 2017

Ionospheric delay, which affect the accuracy of GNSS positioning, is generated by electrons in Ionosphere. Solar activity level, region and time could make change of this delay level. Dual frequency receiver could effectively eliminate the delay using difference of refractive index between L1 to L2 frequency. But, Single frequency receiver have to use limited correction such as ionospheric model in standalone GNSS or PRC(pseudorange correction) in Differential GNSS. Generally, these corrections is effective in normal condition. but, they might be useless, when TEC(total electron content) extremely increase in local area. In this paper, monitoring algorithm is proposed for local ionospheric anomaly using multiple reference stations. For verification, the algorithm was performed with specific measurement data in Ionospheric storm day (20. Nov. 2003). this algorithm would detect local ionospheric anomaly and improve reliability of ionospheric corrections for standalone receiver.

• Journal of the Korean Institute of Gas
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• v.17 no.2
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• pp.28-35
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• 2013

The number of large and complex buildings is growing and they are usually concentrated in metropolitan cities. There is a possibility in such buildings that a small accident can expand to a massive disaster since their scale and complexity. To deal with this issue, a research on gas sensors which can detect multiple gases and early-warning systems has been conducted. Proper criteria or standards are necessary for effective application and operation of such sensor-based disaster monitoring system. In this study, we have proposed the alarm criteria of concentration of hazardous gases for the detection and the alarm release. For each alarm level, systematic disaster response plans consist of responsive actions and information delivery have been prepared. These disaster monitoring criteria can help the detection of hazardous gas-related disaster in the early stage of accident and the provision of appropriate emergency responses.

• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.78-83
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• 2000

Generally, There is to install fire resist shutter or to compart between the office room and the atrium in the atrium buildings in Korea. But, Glass wall that is installed sprinkler which purpose to protect it from fire, is already installed between the office room and the atrium in the advanced nations. We study this problem as follow; We made the fire scenario, and analyze each scenario using FASTLite is fire modeling software and BREAK1 is to predict the window breakage time in the compartment fire. In this study, we can decide that fire compartmentalization between atrium and office rooms doesn't require in Atrium building if the material and fire protection system were reliable. Consequently, Korean Fire Protection Regulations have to consider in direction of increasing freedom of building.

• Journal of the Korean GEO-environmental Society
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• v.15 no.9
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• pp.29-36
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• 2014

Under the situation that the seismic vulnerability are a worsening problem in many world's megacities, the disaster preparedness including earthquake hazards is a matter of primary concern in the capital city of Korea, Seoul. Especially, because it is hard to move or dismantle the architectural heritages, the mitigation of earthquake damages is potentially more difficult than other structures. Moreover, in order to decide the proper preparedness plan against future earthquakes, it is very important to understand how soils pass the seismic waves to architectural heritages. In this paper, therefore, the ground condition and depth of bedrock was investigated by the MASW-method at heritages located in Seoul. Then one-dimensional seismic response analysis was conducted based on the distribution of shear wave velocity. As the major result of analyses, peak acceleration, site amplification factor and natural period are proposed in each site for recurrence period.

• Smart Media Journal
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• v.9 no.3
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• pp.122-129
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• 2020

The possibility that an asymptotic coronavirus-19 infected person around the world is not aware of his infection and can spread it to people around him is still a very important issue in that the public is not free from anxiety and fear over the spread of the epidemic. In this paper, the K-means clustering algorithm and deep learning-based crowd aggregation were proposed to determine the possibility of contact with confirmed cases of infectious diseases. As a result of 300 iterations of all input learning images, the PSNR value was 21.51, and the final MAE value for the entire data set was 67.984. This means the average absolute error between observations and the average absolute error of fewer than 4,000 people in each CCTV scene, including the calculation of the distance and infection rate from the confirmed patient and the surrounding persons, the net group of potential patient movements, and the prediction of the infection rate.

• Journal of the korean veterinary medical association
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• v.46 no.6
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• pp.527-543
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• 2010

구제역은 소 돼지 사슴 면양 산양 고라니 노루 등 우제류 동물에서 발생하는 제1종 가축전염병으로 빠른 시간내에 동물의 입 발굽 젖꼭지 등에 수포를 형성하는 것이 특징이다. 감염된 소의 혓바닥, 잇몸, 입술, 입 내부점막, 주둥이에 크기가 다양한 수포가 형성된다. 심한 경우에 혀 전체 넓은 부위에서 궤양이 형성될 수 있다. 수포는 24시간이내에 정상적으로는 파열되며, 그 수포액은 $10^8/ml$의 역가를 갖는 바이러스를 함유한다. 상피가 떨어지고, 유연이 심해지며, 타액이 입 주변에 흔건히 흘러내린다. 입 주변 병변과 동시 또는 이어서 수포가 발굽에 형성되며, 부분적으로 발굽갓띠 또는 제부의 갈라진 틈에서 생성되어 통증과 파행의 원인이 된다. 수포는 보통 유두와 유방에 발생되며, 때로는 세균성 유방염을 발생시킨다. 생산성의 감소는 보통 25% 정도로 추정된다. 돼지는 초기에 파행, 발열, 의기소침, 식욕부진이 있다. 소 보다 발굽에서 더욱 증상이 심하다. 유두, 유선, 콧등에 수포가 형성된다. 혀의 병변은 소보다 심하지 않다. 잠복기가 2~14일 (소에서의 약 6.2일, 돼지에서는 약 10.2일)로 짧고, 전파가 매우 빠르며 경제적 피해가 크기 때문에 국제 교역에서도 규제대상이 되는 질병이다. 구제역의 병인체는 피코르나바이러스과 아프토바이러스속에 속하는 구제역 바이러스로 현재까지 7개의 혈청형(A, O, C, Asia 1, SAT 1, SAT 2 및 SAT 3)이 알려져 있다. 이 전염병은 동물전염병 중에서 가장 악명 높은 전염병이다. 세계동물보건기구 (OIE)에서도 각 국간에 국제적인 위협을 최소화하기 위하여 질병의 발생을 보고해야 하는 질병으로 특별 관리하고 있다. 2006년 이후 최근까지 아시아 지역에서 지속적으로 많은 발생을 보이고 있다. 금년 들어 중국, 대만, 일본, 몽골, 우리나라까지 발생되어 이 질병의 위험성에 대하여 다시 한번 생각하게 하였다. 구제역의 재발방지를 위하여 최근 동북아시아 지역의 발생상황과 향후 구제역의 발생억제 또는 발생시 긴급 대응을 위하여 해야 할 일은 무엇인지 알아보자.

• Pediatric Infection and Vaccine
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• v.25 no.2
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• pp.107-112
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• 2018

Staphylococcus aureus is now a major community-acquired pathogen worldwide, notably associated with skin and soft tissue infections. Staphylococci are present in the form of colonizers or environmental contaminants at home and increase the risk of recurrent infection. We are describing recurrent familial furunculosis caused by Panton-Valentine Leukocidin-positive methicillin susceptible S. aureus ST1 in Korea. An infant, his father and mother had furunculosis due to methicillin-sensitive S. aureus (MSSA) infection with identical susceptibility patterns. ST1 accounted for all 3 isolates and they were confirmed of having agr group I. Both sec and seh were detected in all isolates using polymerase chain reaction (PCR) assays, and all isolates contained Panton-Valentine leukocidin (PVL) genes. Risk factors for the household spread of S. aureus include skin conditions and close physical contact among household members. The relationship between S. aureus colonization of household contacts and the occurrence of S. aureus infection should be studied into more detail.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.4
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• pp.623-629
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• 1999

The definition of fascial spaces are latent spaces between fascial planes. If infections which spread from dental origin to soft tissue are mild, they are restricted by fascial planes. But, when infections are severe, fascial spaces are often used as a natural pathway which spread to the deep cervical region. If they are not treated at early stage, they may result in the fatal complications as followings; airway obstruction, septicemia, cerebral abscess, and thrombophlebitis etc. The early treatment of fascial space abscess is very important for young children. These case reports present the successful result of fascial space abscess treatment through intracanal drainage without surgical excision. It is proven that the treatment through intracanal drainage has some benefits to the surgical excision, which are as follows: 1) It is economic to the patients or their parents avoiding admission. 2) The treatment procedure is more simple. 3) Childrens can avoid the fearful environment.