• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.1
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• pp.28-34
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• 2010

The spatial distribution characteristics of damaged trees by the pine wilt disease appear scattered spots spreading from single dead trees. That is the reason why it is difficult to early detect damage and to prevent from extensive damage. Thus, it is very important to forecast and analyze the damage occurrences, to establish strategies for prevention, and to supervise them. However, conventional survey which observes around roads or residential areas by naked eyes was impossible to investigate completely, missing target areas and dangerous areas. Therefore, aerial forecasting techniques on the damaged area were developed using GIS, GPS, and helicopters for an accurate observation of systematic and scientific approach in this study. Moreover, advantages of the techniques application were confirmed to survey 972 dead tree samples at 349 position-coordinates in 32 cities (about $28,810km^2$), 2005. This study is expected to apply widely to find dead trees and the causes, particularly by pine wilt disease.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.6
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• pp.586-594
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• 2013

This paper proposes a new coupling element of microwave slot coupler for designing waveguide slot array which can reduce the effect of undesired higher order mode coupling between coupling and radiating slots in the branch waveguide. The proposed device is composed of a centered longitudinal shunt-series coupling slot at the center of broad wall shared by two crossed rectangular waveguides and an asymmetric compound iris that excites the coupling slot. We first have obtained scattering parameters for the proposed coupler by use of EM S/W tool HFSS and then extracted the parameters of T- network equivalent circuit for the coupling slot. We also have analyzed the resonant properties such as resonant length and normalized admittance by changing the geometrical dimensions. The measured results for the fabricated coupler with short-circuited block ${\lambda}_g/4$ away from the coupling slot are well agreed with the simulated ones.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.122-122
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• 2018

1. 배경 최근 IoT 기술이 발전함에 따라 각종 전자기기에 들어가는 센서들이 점점 늘어나고 있다. 특히 사용자 중심의 기기들은 기술이 발전함에 따라 집적화가 이루어지면서, 하나의 기기에서 온도, 습도, 조도 등의 다양한 정보를 처리하고 있다. 이에 따라 더 많은 기능을 사용하기 위해, 소모 전력 또한 점차 증가하고 있다. 그러나 부피는 한정되어 있어, 기존 배터리만으로는 증가하는 소모 전력을 모두 보완하기 어렵다. 또한 대표적인 사용자 중심 기기인 스마트폰에서는, 가장 많은 전력을 소모하는 부분이 점점 커지고 있다. 이에 대한 대책으로 버려지는 에너지를 수확하여 전기적인 에너지로 바꿔주는 에너지 하베스팅 기술이 각광을 받고 있다. 에너지 하베스팅 기술은 바람, 진동, 인체의 움직임 등의 기계적 에너지, 태양광, 실내등의 빛 에너지를 전기적인 에너지로 바꿔주는 기술을 말한다. 본 연구에서는 강유전체 고분자 내부에 양자점이 임베딩된 박막을 이용하여, 스마트폰에서 발생하는 빛 에너지와 손가락으로 디스플레이를 터치할 때 발생하는 기계적인 에너지를 모두 수확할 수 있는 새로운 소자를 제시하였다. 소자 내부에 있는 양자점은 빛 에너지를 산란 혹은 흡수하여 발광한 후, 고분자 내부의 전반사를 통해 양 옆에 있는 태양전지로 빛을 전달한다. 또한 컴포짓의 매트릭스를 이루고 있는 강유전체 폴리머인 P(VDF-TrFE)는 강유전 특성을 통해 마찰전기 에너지를 효율적으로 전기 에너지로 전환할 수 있다. 강유전체 특성에 의해 P(VDF-TrFE) 내부에 정렬된 Polarization은 퀀텀닷에 양자구속 스타크 효과(Quantum Confined Stark Effect)를 일으켜 더 긴 파장을 방출한다. 이렇게 바뀐 파장은 실리콘 태양전지에서 더 많이 흡수할 수 있는 영역으로 방출되어 태양전지 출력의 증가를 일으킨다. 마지막으로 실리콘 태양전지의 출력 증가를 보여줌으로써 이를 실험적으로 입증했다.

• Smart Media Journal
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• v.7 no.1
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• pp.45-51
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• 2018

Avian influenza (AI) is notorious for its rapid infection rate, and has a serious impact on consumers and producers alike, especially in poultry farms. The AI outbreak, which occurred nationwide at the end of 2016, devastated the livestock farming industries. As a result, the prices of eggs and egg products had skyrocketed, and the event was reported by the media with heavy emphasis. The purpose of this study was to investigate the correlation between the egg price fluctuation and the keyword changes in online news articles reflecting social issues. To this end, we analyzed 682 cases of AI-related online news articles for fourteen weeks from November 2016 in South Korea. The results of this study are expected to contribute to understanding the relationship between the actual price of eggs and the keywords from news articles related to social issues.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.917-924
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• 2019

The passive scattering system nozzle of the proton therapy accelerator was simulated to evaluate the neutrons generated by each component in each nozzle by energy. The Monte Carlo N-Particle code was used to implement spread out Bragg peak with proton energy 220 MeV, reach 20 cm, and 6 cm length used in the treatment environment. Among the proton accelerator components, neutrons were the highest in scatterers, and the neutron flux decreased as it moved away from the central flux of the proton. This study can be used as a basic data for the evaluation of the radiation necessary for the maintenance and dismantling of proton accelerators.

• Journal of the Korean Institute of Gas
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• v.15 no.3
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• pp.11-18
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• 2011

Ultrasonic guided waves have been widely utilized for long range inspection of structures. Recently, many researchers have paid attention to the tomographic imaging using guided wave for the diagnosis of plate-like structures because group velocity of guided waves is changed by central frequency of transducer and thickness of plate. Currently, Delay and Sum imaging technique and MVDR(Minimum Variance Distortionless Response) imaging technique are performed. So the performance of these two imaging techniques are investigated in this paper.

• Journal of Environmental Science International
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• v.24 no.9
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• pp.1233-1237
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• 2015

This study was conducted to evaluate the effects of red ginseng marc powder on egg freshness in laying hens during 4 weeks. A total of 60 Hy-line Brown laying hens, 50 week of age, were randomly assigned to 2 groups with diets containing 0% and 2% red ginseng marc powder. There were 3 replications per group with 10 laying hens per pen. Throughout the period of the trial, there were no effects of red ginseng marc powder on egg weight (but not 4 weeks). Haugh Unit (HU) values were observed by showing significant differences between red ginseng marc powder and controls at 0 and 4 weeks, except for HU at 1 through 3 weeks. For egg yolk color, red ginseng marc powder has no difference in comparison with controls at 0, 3 and 4 weeks (but not 1 and 2 weeks). In conclusion, the dietary supplementation with 2% red ginseng marc powder improved HU values throughout the experiment.

• Journal of Environmental Science International
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• v.29 no.7
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• pp.789-792
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• 2020

The present study was investigated the oviposition characteristics of Protaetia brevitarsis seulensis with a focus on winter larvae to improve the utilization of insect resources. The average oviposition tendency and average cumulative number of eggs laid during a 7-week period were measured in adults emerging from larvae that had hibernated for 4 months in five farmhouses. The study covered five zones: Gimje, Jangsu, Wanju, Iksan and Yeoju. The average oviposition tendency over a 7-week period showed increased egg laying between 2 to 3 weeks and 5 to 6 weeks. Overall, it was found that the average cumulative number of eggs laid during the 7-week period was initially low and increased proportionally with time. Our results suggest that using adults that have emerged from hibernated larvae is effective in increasing the oviposition rate and utilization of the insect.

• Journal of Environmental Science International
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• v.29 no.7
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• pp.785-788
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• 2020

We investigated the oviposition characteristics of Protaetia brevitarsis seulensis, focusing on zone breeding throughout the year in terms of the development and utilization of insect resources. To select Protaetia brevitarsis seulensis individuals laying a large number of eggs, the number of eggs laid for each individual was measured for each individual after emergence as adults from larvae grown at room temperature in five farmhouses. The five study zone included Gongju (Tancheon), Gyeonggi (Himsen), Chungnam (Gyeryong), Taean (Wonbuk), and Siheung (Baekse). The average oviposition tendency during a 12-week period obtained from the five regions was somewhat different; however, there was no remarkable difference in overall tendency. The maximum oviposition in Protaetia brevitarsisseulensis in the five regions occurred between 6 and 7 weeks. Compared toother regions, the average cumulative number of eggs laid during the 12-week period was higher (40%-60%) in Gongju (Tancheon) and Gyeonggi (Himsen). These results indicate that in two regions, zone breeding is selected as a system for increasing the demand for insects.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.305-312
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• 2016

This study were compared with the direct measurement and indirect dose methods through various dose calculation in head and wrist. And, the modified equation was proposed considering equipment type, setting conditions, tube voltage, inherent filter, added filter and its accompanied back scatter factor. As a result, it decreased the error of the direct measurement than the existing dose calculation. Accordingly, diagnostic radiography patient dose comparison would become easier and radiogrphic exposure control and evaluation will become more efficient. The study findings are expected to be useful in patients' effective dose rate evaluation and dose reduction.