• Science of Emotion and Sensibility
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• v.11 no.3
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• pp.365-374
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• 2008

Using flight simulator tasks with 48 air force cadets, this research examined the effects of pilots' flight skill and self-esteem on risk-taking behavior in the context of social comparison with their cohorts. Flight skill and self-esteem were assessed for individual cadets and three conditions of social comparison (upward-, downward-, and no-comparison) were devised. Flight simulator situations inappropriate for further approach or landing were designed to assess pilots' risk-taking behavior. Weather conditions in the simulator were inadequate to make a landing and the recommended strategy was to break off the approach and attempt a go-around. In this experiment, pilots' risk taking was measured in terms of their approach altitudes; the lower approach altitudes indicative of the higher risk-taking. Our results showed interaction effects of flight skill, self-esteem, and social comparison on risk-taking behaviors. For pilots who were either high or low in both self-esteem and flight skill, social comparison had no effect on risk-taking behavior. However, pilots with high self-esteem but low flight skill showed more risk-taking behaviors in social comparison conditions. And, pilots with low self-esteem but high flight skill showed risk-aversive behaviors in the downward-comparison condition.

• Journal of Veterinary Clinics
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• v.28 no.2
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• pp.219-224
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• 2011

The health status of three groups of Hanwoo steers (n=157) aged 2-3 years, raised at three different altitudes (600 m, n=50; 200-400 m, n=58; plane land, n=49) and environment with more or less similar management have been evaluated through hematological, biochemical and globulin examinations in order to determine the optimum environment suitable for raising cattle while at the same time minimizing the risk of disease. Five mL of blood samples from each animal were collected by jugular veinipuncture and 2 mL was transferred to a tube containing EDTA for complete blood count (CBC) and 3 mL in lithium heparin for chemistry screening (CS) and immunoassay. Among the CBC parameters a significantly higher white blood cell count (tWBC), total red blood cell count (tRBC), hemoglobin (Hb) and packed cell volume (PCV) were noticed in the high altitude groups, whereas those were lower in the plane land group. In the CS parameters higher levels of aspartate aminotransferase (AST), creatinine, lactate dehydrogenase (LDH) and total bilirubin (TBL) were found in the plane land group, whereas those were lower in the high altitude groups. The total protein (significantly) and globulins were higher in the 600 m group. The results of this study revealed that the overall health status of the Hanwoo cattle based on the hemato-biochemical indices was superior in the highest altitude and inferior in the plane land group but all the parameters were within the reference range in all the groups. Therefore, for recommendation of a suitable environment at an appropriate altitude for raising cattle there need to be further studied along with the hemato-biochemical parameters; considering, breeding, feeding, management, marketing, waste disposal and other factors.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.4
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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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.474-480
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• 2019

We propose a method to evaluate a Modulation Transfer Function (MTF) using a circular target. In addition, a MATLAB GUI-based resolution analysis tool was developed to enhance the reliability of UAV image quality and the efficiency of the work. For this purpose, images were taken with an FC-6310 during flights at altitudes of 80 m, 120 m, and 150 m and by an iXM-100 at altitudes of 150 m, 200 m, and 400 m. The MTFs of UAV images were compared with traditional photogrammetry by measuring and analyzing MTFs on images taken by the UltraCAM Eagle Mark-2 sensor at a flight altitude of 1000 m. The results show that ${\sigma}MTF$ of the FC-6310 were 0.431(80 m), 0.524(120 m), and 0.699(150 m), and those of the iXM-100 were 0.332(150 m), 0.393(200 m), and 0.631(400 m), respectively. At the altitude of 150 m, the image quality of the iXM-100, which has a high-performance camera, was very high, and the effect of the camera performance on the image quality was confirmed. In addition, the ${\sigma}MTF$ of the UltraCAM Eagle Mark-2 was 0.711 due to the high flight altitude. This was the worst value among all UAV images. However, the ${\sigma}MTF$ of the FC-6310 at 150-m altitude was 0.699, which is almost the same as that of a manned aerial image.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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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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• v.20 no.2
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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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• v.17 no.9
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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.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.3
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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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• v.13 no.1
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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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• v.33 no.3
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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.