• ETRI Journal
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• 제45권5호
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• pp.781-794
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• 2023

Uncrewed aerial vehicles (UAVs) have become a vital element in nonterrestrial networks, especially with respect to 5G communication systems and beyond. The use of UAVs in support of 4G/5G base station (uncrewed aerial vehicle base station [UAV-BS]) has proven to be a practical solution for extending cellular network services to areas where conventional infrastructures are unavailable. In this study, we introduce a UAV-BS system that utilizes a high-capacity wireless backhaul operating in millimeter-wave frequency bands. This system can achieve a maximum throughput of 1.3 Gbps while delivering data at a rate of 300 Mbps, even at distances of 10 km. We also present the details of our testbed implementation alongside the performance results obtained from field tests.

• 복식
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• 제58권3호
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• pp.116-122
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• 2008

This study aims at defining the meaning of Pobeckchuck in the historical view-point, which appeared in the History of Joseon Dynasty, regarding the periods from the ruling period of Sunjo to that of Sunjong as the latter part of history. Pobeckchuck used in King Sejong was redressed in accordance with the measurement in the Kyeonggukdadejeon(code), in which time one Pobeckchuck was 46.80cm long. It is known that Juchuck, Hwangjongchuck, Youngjochuck, Joraegichuck etc. which had been used in the ruling period of Sejong Dynasty, were used till the period of Youngjo. Also, the document shows that in the 12th ruling period of Sunjo, Pobeckchuck was used for measurement, and in the 20th ruling period of Sunjo, newly-made ruler was only used for the measurement of fields, but no more details about how long it was. But according to the document complied at that time, one Pobeckchuck was 46.80cm long, which fact reveals that the same measurement was used as in the ruling period of Sunjo. When all the measurement laws which were established in the 3rd year of Junghee, the 6th year of Kwangmu were abolished, Pobeckchuck was solely banned from its use, which fact offers a glimpse of how confusing at that period was. The comparison and examination among many documents in the latter part of Joseon Dynasty show the differences within about 4cm that one Pobeckchuck ranged from 44.80cm to 48.80cm long. But no other document on measurement appeared in the History of Joseon Dynasty, except for the 46.80cm. Thus, the 46.80cm corrected in the ruling period of Sunjo proves that one chuck in Pobeckchuck adopted by the dynasty was used as the measurement of length till the ruling period of Sunjong.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1656-1662
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• 2013

The ternary phase $EuZn_xIn_{4-x}$ has been identified as the main product of reactions of Eu, Zn, and In by using the In-flux method and characterized by both powder and single-crystal X-ray diffraction. The structure belongs to the common $BaAl_4$-type (tetragonal space group I4/mmm, Pearson code tI10) with lattice parameters of a = 4.5610(9) ${\AA}$, c = 12.049(3) ${\AA}$ for composition $EuZn_{1.10(12)}In_{2.90}$ and a = 4.5463(3) ${\AA}$, c = 12.028(2) ${\AA}$ for composition $EuZn_{1.18(2)}In_{2.82}$, respectively. In this structure, the Eu atoms are situated at the center of 18-vertex Fedorov polyhedra made of Zn and In atoms, where the 4d site is preferentially occupied by In and the 4e site is occupied by randomly mixed Zn and In atoms. Theoretical investigations using tight-binding linear muffintin orbital (TB-LMTO) method provide rationale for the observed site preferences and suggest potentially wider homogeneity range than the experimentally established for $EuZn_xIn_{4-x}$ ($x{\approx}1.1$).

• 전자공학회논문지
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• 제51권8호
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• pp.104-113
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• 2014

HEVC(high efficiency video coding) 표준에서 사용되는 기존의 rough mode decision(RMD) 알고리즘은 transform skip mode(TSM)와는 연관성이 낮은 DCT를 기반으로 하는 모드 선택 방법을 이용하고 있다. 따라서 기존 RMD의 결과로 구한 후보 모드가 TSM에서 사용될 때, 압축 효율이 손실되고 인코딩 시간을 낭비하게 된다. 본 논문은 HEVC에서의 TSM을 위한 새로운 RMD를 제안한다. 우리가 제안한 RMD 알고리즘은 TSM에서 최선의 모드를 선택할 확률을 높이는 새로운 비용 함수를 제안하여 코딩 효율을 향상시킨다. 또한, 제안하는 알고리즘은 새롭게 제안한 임계값을 기준으로 선택 가능성이 거의 없는 TSM의 인코딩 과정을 생략하여 인코딩 시간을 줄인다. 실험 결과 제안하는 방식은 HEVC 표준에 비해서 10%의 인코딩 시간을 줄이며 스크린 콘텐츠에 대해서 0.3%의 압축률을 향상시킨다.

• Current Photovoltaic Research
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• 제2권4호
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• pp.168-172
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• 2014

Under concentrated illuminations, the solar cells show higher efficiencies mainly due to an increase of the open circuit voltage. In this study, InGaP/InGaAs/Ge triple-junction solar cells have been grown by a low pressure metalorganic chemical vapor deposition. Photovoltaic characteristics of the fabricated solar cells are investigated with a class A solar simulator under concentrated illuminations from 1 to 100 suns. Ideally, the open circuit voltage should increase with the current level when maintained at the same temperature. However, the fabricated solar cells show degraded open circuit voltages under high concentrations around 100 suns. This means that the heat sink design is not optimized to keep the cell temperature at $25^{\circ}C$. To demonstrate the thermal degradation, changes of the device performance are investigated with different bonding conditions and heat sink materials.

• 한국도서관정보학회지
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• 제44권3호
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• pp.429-446
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• 2013

이 연구는 조선시대 전남지방의 읍지편찬활동을 파악하는 연구의 일환으로, 장흥(長興)의 읍지를 중심으로 살펴보았다. 이는 전남의 다른 지역의 읍지편찬 연구를 체계화하는데 도움이 될 수 있을 것이다. 현존하는 장흥의 읍지를 조사하여 체계화하였으며, 개별 읍지의 내용과 체재를 살펴서 장흥에서 편찬된 읍지의 특성을 고찰하였다. 그 결과 영조조부터 1910년까지 10종의 읍지가 현존하였고, 고종조에서 편찬한 읍지가 4종이었다. 읍지의 체제는 "신증동국여지(新增東國輿地) 승람(勝覽)"의 항목을 기본으로 하고 추가항목을 더하여 기술하고 있다. 장흥읍지의 특성은 1) 각 방(坊)중심으로 기술한 읍지가 3종 있는데, 인물(人物)항목에서 그들의 공동체 의식과 성리학적 교화사상을 반영하는 것으로 해석된다. 2) 군사(軍事) 항목 중심의 읍지가 2종이 있는데, 당시 수군(水軍)에 대한 상세한 정보와 장흥의 군사적 중요성을 확인할 수 있다. 3) 관찬읍지(官撰邑誌)가 4종 있는데, 읍지의 내용과 체재가 영조조와 고종조의 시대상을 반영하였다. 또한 "함주지", "김해읍지"와 비교한 결과 "장흥읍지"는 지리적 요건 상 국방의 요충지적 성격이 강하게 드러나고 있다.

• 건축역사연구
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• 제19권2호
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• pp.101-116
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• 2010

Jangan-sa is one of the Buddhist temples in the southeastern seaside district, which was restored directly after the termination of Japanese Invasion of Korea in 1592. Recently we could find out 4 records on the constructions of Daeoong - jeon in J angan-sa. These are written in the 12th year of Emperor Soonchi, written in the 8th year of Emperor Geonryung, written in 1947 Buddha Era and written in 1951 Buddha Era. Until the revelation of these records, the present building has been considered to be built in 1657, the 8th year of King Hyojong, based upon Kim Bang - han's "Jangan - sa Daeoong - jeon - gi". Because the gongpo of Daeoong - jeon was finished with the type of the late period of Chosun Dynasty, we doubt of the correction on it's building date, just in the year of 1657. Now we are able to examine the building date and the alteration date, based upon the actual measurement and constructional records of Daeoong - jeon. So to speak, the building destroyed in 1592, had been restored in 1658, the 9th year of King Hyojong and was reconstructed in 1744, the 20th year of King Youngjo. Afterward it was repaired on small scales in 1947 and in 1951. Though this building is considered to be lack of the completeness owing to the later alterations, it is still worthy heritage for the research on the building type at the directly after the termination of Japanese Invasion of Korea in 1592.

• 응용통계연구
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• 제29권5호
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• pp.977-985
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• 2016

노숙문제는 주거의 부재라는 문제뿐만 아니라 실업, 가족해체, 사회적 배제, 건강 및 자살문제 등과도 복합적으로 얽혀있는 사회문제로서 인식되고 있다. 본 논문은 노숙인의 취약한 정신건강 상태를 지적하는 기존의 연구들을 바탕으로, 중독의 실태 및 세대에 따른 중독유형의 특수성의 실재여부를 탐색하기 위하여 노숙인들의 중독 및 정신건강 실태에 대한 설문조사를 실시하였다. 조사결과, 알코올중독은 주로 장년층에서 나타난 반면 인터넷 중독 및 스마트폰 중독은 주로 청년층에서 나타나는 경향을 보였다. 현재 청년노숙인들을 다루는 연구가 극히 드물 뿐더러, 알코올을 제외한 노숙인들의 중독현황에 대한 연구가 부재한 상황이다.

• 한국의사학회지
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• 제33권2호
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• pp.77-87
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• 2020

Objective : The Annals of the Joseon Dynasty is a primary historical record that has provided a great deal of information about what the Joseon Dynasty was like. However, as of yet, we know very little about the medical officers in Joseon dynasty, such as their government posts and official ranks. The purpose of this study is look in to the activities, government posts, and official ranks of the medical personnel by examining Yeongjosillok. Methods : First, I selected historical records containing '醫' in Yeongjosillok. Then, I organized medical officers' name by reading each record. I screened historical records in Yeongjosillok with their names to analyze their activities, government posts, and official ranks. When there was limited information available, I referred to The Daily Records of Royal Secretariat of Joseon Dynasty. Results : I found 262 historical records in Yeongjosillok containing '醫'. Then I found 26 people who served as medical officers in Yeongjosillok. Also, l found that 11 government posts and 7 official ranks were awarded to them throughout the 110 historical records in Yeongjosillok and The Daily Records of Royal Secretariat of Joseon Dynasty. Conclusion : Through this study, I was able to examine the detailed activities of unknown medical officers by studying the historical records in Yeongjosillok and The Daily Records of Royal Secretariat of Joseon Dynasty. Under the Joseon Dynasty's class-based society, the middle class had various restrictions. However, I found that medical officers that belonged to the middle class received exceptional treatment despite their social status.

• 응용통계연구
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• 제28권2호
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• pp.289-294
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• 2015

생동성 시험과 같은 임상약리학분야의 연구는 일반적으로 한 개체 내에서 반복하여 측정된 자료구조를 사용하므로 선형혼합모형을 이용하여 분석하는 것이 보편적이다. 이러한 모형에서 랜덤효과는 개체 내 관측 자료 사이의 상관관계를 설명하고, 공분산행렬은 개체-내 변동을 설명한다. 생동성 분석은 두 약물의 약동학적 변수인 Cmax와 AUC의 기하평균비에 대한 90% 신뢰구간이 동등성 한계인 [0.8, 1.25] 범위에 드는지 알아보는 분석으로, 고정효과에는 시기, 순서군, 치료효과를, 랜덤효과에는 개체효과를 가지는 선형혼합모형을 이용하여 분석한다. 이러한 분석이 적용된 실제 예를 살펴보기 위하여 레보플록사신 연구의 자료를 활용하였다.