• 감성과학
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• 제11권3호
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• pp.365-374
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• 2008

조종사의 비행수행능력과 자존감이 비행비교 상황에서 위험행동에 미치는 영향을 알아보기 위해 비행교육과정 조종사 48명을 대상으로 시뮬레이터 상황실험을 실시하였다. 피험자간 변인으로서 비행수행능력(비행등수)과 자존감 척도로 각각의 높고 낮은 그룹으로 나누어 안전규칙상 착륙이 허가되지 않는 활주로 접근 시뮬레이션 상황을 수행하게 하였다. 접근 상황은 피험자 내 설계로 세 번에 걸쳐 측정하였고, 동일한 각각의 상황실험 수행 직전에 실험참가자에게 다른 사람들의 수행결과를 조작(긍정비교, 부정비교, 통제)하여 제시하였다. 실험참가자의 위험행동은 접근한 고도를 통하여 측정하였다. 실험 결과 각 제시 조건에 따라 위험행동이 유의미하게 차이가 나타났고, 각 비교조건에서의 위험행동 경향은 비행수행능력과 자존감의 수준에 따라 달라지는 상호작용 효과가 나타났다. 비행수행능력이 낮은 집단은 비교조건들에서 통제조건과 달리 위험한 행동을 하는 것으로 나타났고 비행수행능력이 높은 집단은 부정비교조건에서 다른 조건들과 달리 위험을 회피하는 경향을 보였다. 자존감이 높은 집단은 통제조건에 비해 비교조건들에서 유의미한 위험행동을 보인 반면, 자존감이 낮은 집단은 다른 조건들에 비해 부정적 비교조건에서 유의미한 위험회피행동을 보였다.

• 한국임상수의학회지
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• 제28권2호
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• pp.219-224
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• 2011

서로 다른 고도에서 사육하고 있는 2-3세령의 수컷, 건강한 비육 한우를 세 그룹(600 m, n=50; 200-400 m, n=58; 0 m n=49)으로 나누어 혈액 및 혈청검사 그리고 면역항체가 검사를 실시 하였다. 고도를 제외한 일반 사육 환경과 식이 및 축사의 형태는 매우 비슷한 조건이였으며 질병이 확인 된 개체는 통계에서 제외 하였다. 경정맥에서 채취한 혈액은 일반혈액검사 중 WBC, RBC, Hb, PCV 를, 혈청화학검사 중 AST, LDH, TBL를 집중적으로 비교 분석하였으며 또한 면역학적 검사를 실시하였다. 고도가 높은 그룹이 낮은 그룹에 비하여 CBC에서는 조금 높게 나타났으며, 혈청검사에서는 평지에서 사육된 한우가 조금 높게 나왔다. 그러나 모두가 정상범위를 벗어나거나 통계적으로 유의한 수준의 차이를 보이지 않았다. 이러한 결과는 지금까지 알려진 대부분의 연구결과와는 차이가 있는 것이다. 본 연구와 지금까지의 알려진 연구와의 이러한 차이는 과거의 연구들은 고도의 차이가 현저한 경우가 대부분이었으나 본 연구에서 조사한 지역은 서로 고도가 비슷한 점에서 생긴 결과라고 여겨지며, 특히 고도가 600m 이하인 지형에서는 서로 큰 영향을 받지 않는 것으로 생각된다. 따라서 한우의 경우 목장 시설의 건축시 지형에 따른 어려움과 주변에서 들여오는 조사료의 수송에 따른 경제적 불리, 축산폐수 처리는 물론 퇴비의 활용 등 전반적인 목장 관리 면에서 고도가 높은 산지 보다는 평지가 권장된다.

• 한국환경복원기술학회지
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• 제15권4호
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• pp.81-95
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• 2012

This study was intended for Fagus engleriana stand in Is. Ulleung where the disturbance of vegetation has been caused by the exploitation and the increase of tourists. For the effective conservation and management on this issue, this study was conducted provide basic data. The sixteen study sites ($20{\times}20m$) were installed in the dominant Fagus engleriana stand and the base environment and vegetation were investigated. The Fagus engleriana stand was classified into two groups, The Fagus engleriana stand was classified into two groups, community A is Fagus engleriana-Sorbus amurensis and community B is Fagus engleriana-Acer pictum subsp. Mono by cluster analysis and community A were nothing signigicant by indicator species analysis. Community B were Eight species (Tsuga sieboldii, Camellia japonica, Dystaenia takesimana ect.) significant by indicator species analysis. The diameter class of 16cm to 25cm was 53.7% in population structure of Fagus engleriana, which was the highest and showed inverse J-distribution. Species diversity index (H') of investigated woody layer group ranged from 0.99 to 2.05 and that of under layer group ranged from 1.75~2.59. According to Non-metric Multidimensional Scaling (NMS) analysis, the woody layer was divided into community A developed in the region having relatively high sand content at high altitudes and community B formed at the place having relatively high clay content at low altitudes. Then this classification was significant through Multi-Response Permutation Procedures (MRPP) analysis. The distribution of understory vegetation through Detrended Correspondence Analysis (DCA) was induced by the silt content and cover degree of vegetation layer.

• 한국산학기술학회논문지
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• 제20권9호
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• pp.474-480
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• 2019

본 연구에서는 무인항공영상의 품질 평가를 위해 공간해상도 검정 방법 중 하나인 MTF(Modulation Transfer Function)를 Circular target을 이용하여 평가하는 방안을 제시하고, MATLAB GUI 기반 해상도 분석 Tool을 제작하여 무인항공영상 품질의 신뢰도와 작업의 효율성을 높이고자 하였다. 이를 위해 무인항공기체인 DJI Phantom 4 Pro(FC 6310)기체는 80m, 120m, 150m, Matrice 600(iXM-100)기체는 150m, 200m, 400m의 서로 다른 고도에서 촬영하였으며, 유인항공영상과 비교를 위해 UltraCAM Eagle Mark 2 센서로 비행고도 1000m에서 영상을 촬영하여 MTF를 비교하였다. 연구 결과 DJI Phantom 4 Pro(FC 6310)기체의 ${\sigma}MTFs$ 수치는 촬영고도에 따라 0.431, 0.524, 0.699, Matrice 600(iXM-100)기체의 ${\sigma}MTFs$ 수치는 촬영고도에 따라 0.332, 0.393, 0.631의 결과를 나타내어 촬영고도가 높아질수록 영상의 품질이 낮아짐을 알 수 있었다. 동일한 고도인 150m의 경우 탑재된 카메라의 성능이 높은 Matrice 600(iXM-100)기체의 영상품질이 매우 높은 결과를 나타내어 카메라의 성능이 영상의 품질에 미치는 영향을 확인할 수 있었다. 또한, UltraCAM Eagle Mark 2 센서를 탑재한 유인항공영상의 ${\sigma}MTF$ 수치는 높은 비행고도로 인하여 0.711의 결과를 나타내어 모든 무인항공영상의 품질보다 낮은 결과를 나타내었다. 하지만 DJI Phantom 4 Pro(FC 6310)기체의 150m 고도에서 촬영한 무인항공영상에서 ${\sigma}MTF$ 수치는 0.699의 결과를 나타내어 유인항공영상의 품질과 거의 비슷한 결과를 나타내었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.195-196
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• 2014

Unlike general construction works, bridge construction is mostly done in a high place. The conventional deck form of bridge is installed between precast concrete girders using sleepers, bridging joints and plywoods, and after concrete is poured to the deck, the form materials are removed at high altitudes. When removing the form, it may be dropped on ground, damaging the materials and resulting in economic loss. In addition, safety accidents are likely as the works are performed in a high place, and as the manpower increases, the cost increases. Also, it is difficult to install and remove temporary equipment. Therefore, it is required to develop a system form that allows easier and quicker installation and removal by unskilled workers and ensures safety of workers. In this regard, the study is intended to analyze requirements for the system form for pouring concrete to bridge decks, which can be easily installed and removed. The study result will be used as basic information for development of the system form for pouring concrete to bridge decks.

• The Korean Journal of Ecology
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• 제20권2호
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• pp.125-132
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• 1997

A study of forest vegetation in Mt. $T\v{o}kyu$ National Park was investigated by ordination technique. By TWINSPAN(Two-Way Indicator Species Analysis) method, 10 groups were recognized as follows: pinus densiflora, Quercus variabilis, Quercus serrata, Quercus mongolica-Rhododendron schlippenbachii, Quercus mongolica-Abies koreana, Quercus mongolica-Acer pseudo-sieboldi-amum, Quercus mongolica-Symplocos chinensis for. pilosa, Carpinus laxiflora, Fraxinus mandshurica and Taxus cuspidata groups. The floristic composition of these groups showed high correlation to soil moisture(r=0.831), altitude(r=0.784), topography(r=-0.722), organic matter(r=0.642), and pH(r=-0.509) among various environmental factors. According to the results of CCA(Canonical Correspondence Analysis) Pinus densiflora group and Quercus variabilis group were situated in a xeric area at a lower altitude where soil nutrients were poor compared with the other groups. Fraxinus mandshurica group was distributed throughout the valley with high soil moisture and good nutrients, Quercus serrata group and Carpinus laxiflora group were found in the low altitude region with good nutrients, Quercus mongolica group, at the high altitude region with good nutrients, and Quercus mongolica-Acer koreana and Taxus cuspidata at higher altitudes(1, 400-1600 m).

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권9호
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• pp.2590-2608
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• 2023

The high-altitude and mobility characteristics of unmanned aerial vehicles (UAVs) have made them a key element of new radio systems, particularly because they can exceed the limits of terrestrial networks. However, at high altitudes, UAVs can be significantly affected by intercell interference at a high line-of-sight probability. To mitigate this drawback, we propose an algorithm that selects the optimal beam to reduce interference and maximize transmission efficiency. The proposed algorithm comprises two steps: constructing a user-location-based fingerprint database according to the user types presented herein and cooperative beam selection. Simulations were conducted using cellular cooperative downlink systems for analyzing the performance of the proposed method, and the signal-to-interference-plus-noise cumulative distribution function and spectral efficiency cumulative distribution function were used as performance analysis indicators. Simulation results showed that the proposed algorithm could reduce the effect of interference and increase the performance of the desired signal. Moreover, the algorithm could efficiently reduce overheads and system cost by reducing the amount of resources required for information exchange.

• 한국항공운항학회지
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• 제31권3호
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• pp.50-58
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• 2023

Sudden wind changes at low altitudes pose a significant threat to aircraft operations. In particular, airports located in regions with complex terrain are susceptible to frequent abrupt wind variations, affecting aircraft takeoff and landing. To mitigate these risks, Low Level Wind shear Alert System (LLWAS) have been implemented at airports. This study focuses on understanding the characteristics of wind shear and developing a prediction model for Jeju International Airport, which experiences frequent wind shear due to the influence of Halla Mountain and its surrounding terrain. Using two years of LLWAS data, the study examines the occurrence patterns of wind shear at Jeju International Airport. Additionally, high-resolution numerical model is utilized to produce forecasted information on wind shear. Furthermore, a comparison is made between the predicted wind shear and LLWAS observation data to assess the prediction performance. The results demonstrate that the prediction model shows high accuracy in predicting wind shear caused by southerly winds.

• Journal of Astronomy and Space Sciences
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• 제13권1호
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• pp.40-47
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• 1996

One of the important effects of the space environment on the satellites and spacecrafts is the single event upsets (SEUs) which are caused by the high energy particles in space. A SEU occurs when an ionizing radiation produces a burst of electron-hole pairs in a digital microelectronic circuit and causes the charge state to change. We have developed and integrated a software package which can estimate the SEU rates for any specified locations or altitudes under various geophysical conditions. We report in this paper the algorithm of the software and the results for some devices with known parameters. We also compare the results with actual observations made by Akebono.

• Journal of Ecology and Environment
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• 제33권3호
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• pp.223-228
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• 2010

Soil microbes perform crucial roles in the nutrient cycles of forest ecosystems, by effecting the decomposition of organic matter. Enzyme activities have been used to evaluate decomposition rates, as well as microbial activities. The principal objectives of this study were to determine the activities of different soil enzymes, to compare enzyme activities at different elevations, and to elucidate the most important controlling variables for enzyme activities. We conducted a field survey at three sites in Mt. Jumbong on a monthly basis from May, 2004 to September, 2005. Enzyme activities did not change substantially over different seasons. However, the spatial differences were distinct; the lowest elevation site evidenced the lowest levels of enzyme activity. Soils at the lowest elevation were nutrient-depleted soils, and enzyme activities appeared to be affected by precipitation and temperature. However, enzyme activities in fertile soils at high elevations were associated with nutrients and organic matter. The enzyme activities detected in this study differed significantly at the three elevations, and their controlling variables also evidenced different factors.