• Journal of Trauma and Injury
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• v.19 no.1
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• pp.54-58
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• 2006

Purpose: The committee on trauma of the american college of surgeons, in its manual resources for optimal care of the injured patients involved in falls from less than 20 feet need not be taken to trauma centers. Because triage criteria dictate less urgency for low-level falls, this classification scheme has demerits for early detection and treatment of serious problems in the emergency room. Methods: A prospective analysis was conducted of 182 patients treated for fall-related trauma from June 2003 to March 2004. Falls were classified as group A (<3 m), group B (${\geq}3m$, <6 m), and group C (${\geq}6m$). Collected data included the patient's age, gender, site and height of fall, surface fallen upon, body area of first impact, body regions of injuries, Glasgow Coma Scale (GCS), Revised Trauma Score (RTS), and Injury Severity Score (ISS). Results: The 182 patients were classified as group A (105) 57.7%, group B (61) 33.5%, and group C (16) 8.8%. There was a weak positive correlation between the height of fall and the patients' ISS in the three groups (p<0.001). There were significant differences in GCS (p=0.017), RTS (p=0.034), and ISS (p=0.007) between group A and B. In cases that the head was the initial impact area of the body, the GCS (p<0.001) and the RTS (p=0.002) were lower, but the ISS (p<0.001) was higher than it was for other type of injuries. Hard surfaces as an impact surface type, had an influence on the GCS (p<0.001) and the ISS (p=0.025). Conclusion: To simply categorize patients who fall over 6 meters as severely injured patients doesn't have much meaning, and though patients may have fallen less than 6 meters, they should be categorized by using the dynamics (impact surface type, initial body - impact area) of their fall.

• Journal of the Korean association of regional geographers
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• v.2 no.2
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• pp.93-102
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• 1996

The Korean Peninsula is located on the east coast of monsoon Asia of the midlatitude, where the Pacific polar front moves. As a result variations of spatial and temporal distribution of precipitation occur. A great variation of precipitation during the summer months created frequent droughts and floods. The purpose of this study is to identify distributional characteristics and to analyze synopic characteristics of summer droughts in Korea. The research methods used are ; (1) to identify droughts based on the anomaly of monthly precipitation during summer of 1994. (2) to analyze correlations between drought and weather systems by using the calender of rain days. (3) to compare a synoptic mechanism of summer droughts with that of typical normal summer. The characteristics of summer droughts of 1994 may be summarized as follows ; 1) While most regions were affected by the droughts some regions displayed specific characteristics. The southern part of the Korean Peninsula was severely affected during the month of June. August droughts severely affected east part of the Sobek Mountains, thus showing that the droughts of June and August are highly localized. 2) In the pressure anomaly of surface field. the positive anomaly appears in June around Korean Peninsula, but in July when all parts of the South Korea were under severe droughts, the anomaly changes and becomes negative. 3) Extracyclones occurred less frequently in the summer of 1994. Those that did occur were located in areas far off the Korean Peninsula having little consequences on the drought patterns. 4) The trough of westerly wave at 500hPa height patterns in June is located far from the eastern sea of Korean Peninsula, but in July and August Korean Peninsula belongs to ridge of westerly wave. 5) In June the positive height anomaly at 500hPa surface appears zonally from Siberia to the western Parts of North Pacific Ocean, and in July and August, the strong positive anomaly appears around Korean Peninsula. As a result the zonal index of westerlies at during each month of summer in Korean sector has a large value, which in turn implies that drought will prevails when zonal flow is strong.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.2
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• pp.99-109
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• 1994

The objective of this study was to examin some animal and sward factors which determine the daily herbage intake of high yielding dairy cows at different levels of daily herbage allowance. In this paper, the principal data relevent to the changes of sward characteristics after five days of daily strip grazing at three experimental peliods were summarized. The pregrazing herbage mass and extended height increased significantly from 5,047 kg OM/ha and 341 mm in period 1 to 6,877 kg OM/ha and 446 mm in period 3, while there was not a significant difference among herbage allowance treatments(average 6,068 kg OM/ha and 410 mm). The live leaf material in the residual herbage showed a greater reduction than the dead material and leaf sheath in terms of extended height, proportion and density. The decreased rates after grazing were higher when the level of herbage allowance decreased. Live leaves were vertically distributed to 50 cm of sward height before grazing. All live lamina distributed to 25 cm were grazed in the high and medium, and to 20 cm in the low levle of herbage allowance after grazing. The depth of grazing and grazed volume of forage material were heighly affected by the levels of hehage allowance. The biomass after grazing in the high, medium and low daily herbage allowance decreased 35, 36 and 52%, respectively, compared to before grazing level. The highly significant correlations between herbage allowance and extended tiller height(r=0.79), proportion of live lamina(r=0.94) and density of live lamina(r=O.91) after grazing, respectively, were observed.

• Journal of The Korean Association For Science Education
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• v.22 no.3
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• pp.560-570
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• 2002

This study was focused on whether secondary science teachers have consistent, integrative scheme on the definition of atmospheric pressure and phenomena caused by air pressure. We had made questionnaire and let 94 science teachers answer. We sorted the responses according to their major, school and compared them with the description in textbooks. The result can be summarized into three findings. First of all, teachers whose major is chemistry have strong tendency to understand that atmospheric pressure is caused by molecular motion though it, in textbooks, is defined as the pressure by weight of air mass. The half of respondents believed that decreasing of atmospheric pressure in high altitude is due to molecular motions, while most textbook says decrease in the weight of air mass. Secondly, many science textbooks show that air mass expands, rises, becomes less dense and the pressure of atmosphere becomes low when it receives heat. So, most of respondents explained low pressure is formed by lower density. Thirdly, they answered that they just teach the phenomena of air pressure by using the textbooks which mainly deal with the present state rather than a principle. In conclusion, the science textbooks should present the exact description and consolidated structures of those concepts to prevent students from having misconceptions on air pressure. In addition, training program for science teachers would be necessary to reconsider and explore the natural phenomena in various viewpoints.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.763-768
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• 2002

This study was performed in the airlift bioreactor using the nitrifier consortium entrapped in polyvinyl alcohol(PVA) for removing low concentration total ammonia nitrogen(TAN). At the superficial air velocity of 0.83 cm/sec, TAN removal rate and removal efficiency was $316.6{\pm}7.2g/m^3{\cdot}day$ and $92.8{\pm}2.2%$ respectively. Removal rate was continuously increased with decreasing hydraulic residence time(HRT) from 0.5 hr to 0.05 hr, whereas removal efficiency decreased with decreasing HRT. The optimum temperature for nitrification was $30^{\circ}C$ at which removal efficiency was $95.5{\pm}1.5%$. Nitrification was effectively performed at low temperature, $10^{\circ}C$. In the pH range from 7 to 9 in the bioreactor, removal rate and removal efficiency was $310{\pm}10g/m^3{\cdot}day$ and $94{\pm}3%$ respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1C
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• pp.89-96
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• 2012

Since tactical robots are going to be grown and tactical data communications will be more network-centric, the reliability of wireless tactical data networks is going to be very important in the future. However, the connectivity of such wireless tactical data networks can be extremely uncertain in practical circumstances. In this paper, we propose a searching technique to find out the weak boundary area of the network connectivity using a small UAV(unmanned aerial vehicle) which has a simple polling access function to wireless nodes on the ground in wireless tactical data networks. The UA V calculates the network topology of the wireless tactical data networks and coverts it to the Lapalcian matrix. In the proposed algorithm, we iteratively search the eigenvalues and find a minimum cut in the network resulting in finding the weak boundary of the connectivity for the wireless tactical data networks. If a UAV works as a relay nodes for the weak area, we evaluate that the throughput performance of the proposed algorithm outperforms star connection method and MST(minimum Spanning Tree) connection method. The proposed algorithm can be applied for recovering the connectivity of wireless tactical data networks.

• Journal of the Korean association of regional geographers
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• v.3 no.1
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• pp.51-62
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• 1997

In various places of drainage basins of major rivers in South Korea are distributed intermontane basins. Basin floor covered with fluvial deposits carried from the surrounding mountane area becomes alluvial plain. Its productivity is comparatively higher than anywhere else. Thus basin is a local administrative, economic, and cultural core area. Intermontane basin consists of backward mountane area, gentle hills, and alluvial lowland. The purpose of this paper is to elucidate the morpogenetic processes and development age of Angae Basin located in the sedimentary rock region. Hills with the height of a.s.l. $80{\sim}100m$ distributed in Angae Basin are residual landforms, which are the remnants of dissection of the etchplain that results from the denudation of bedrock deeply weathered along tectolineaments under the warm and moist climate, and reflect lithological differentiation of bedrock. Those hills have been comparatively higher ridges since the initial stage of the original etchplain, and they have been immune from fluvial processes. The etchplain appeared as $80{\sim}100m$ hills. the high terrace distributed in upstream reach of Nakdong River drainage basin and the old meander-cut at Seoburi in Wicheon drainage basin, are formed at the same stage when riverbed of Wicheon Stream functioned as a local base level according as the fluvial system of Wichoen arrived at dynamic equilibrium.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.3
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• pp.167-175
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• 2019

Water color analysis allows non-destructive estimation of abundance of optically active water constituents in the water body. Recently, there have been increasing needs for light-weighted multispectral cameras that can be integrated with low altitude unmanned platforms such as drones, autonomous vehicles, and heli-kites, for the water color analysis by spectroradiometers. This study performs the preprocessing of the Micasense Rededge-M camera which recently receives a growing attention from the earth observation community for its handiness and applicability for local environment monitoring, and investigates the applicability of Rededge-M data for water color analysis. The Vignette correction and the band alignment were conducted for the radiometric image data from Rededge-M, and the sky, water, and solar radiation essential for the water color analysis, and the resultant remote sensing reflectance were validated with an independent hyperspectral instrument, TriOS RAMSES. The experiment shows that Rededge-M generally satisfies the basic performance criteria for water color analysis, although noticeable differences are observed in the blue (475 nm) and the near-infrared (840 nm) band compared with RAMSES.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.511-519
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• 2021

Slewing bearing is applied to the transmission of rotational power of the body and turret in a special vehicle for anti-aircraft weapons that overcomes the enemy flight system approaching at low altitudes with rapid response fire. When the turret load and impact load generated when shooting are combined in performing the combat mission of a special vehicle, structural stability must be secured to achieve a successful function. Among the components of the slewing bearing, the stability of the components against the complex loads acting by the turret drive and shooting was evaluated by considering the shape and material characteristics of the ring-gear, roller, and wire-race. As a research method for stability evaluation, based on engineering theory, the strength characteristics of the components were examined by numerical calculations. Finite element analysis was performed on components using the ANSYS analysis program. The results of theoretical analysis and the results of finite element analysis were very similar. A structural stability evaluation for the slewing bearing, which was performed mainly on the analysis, confirmed that the design strength of the slewing bearing determined in the preliminary design in the early stage of localization development was sufficient.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1393-1405
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• 2020

UAV (Unmanned Aerial Vehicle) can acquire high-resolution images due to low-altitude flight, and it can be photographed at any time. Therefore, the UAV images can be updated at any time in map production. Due to these advantages, studies on the possibility of producing large-scale digital maps using UAV images are actively being conducted. Precise digital maps can be used as base data for digital twins or smart cites. For producing a precise digital map, precise sensor modeling using GCPs (Ground Control Points) must be preceded. In this study, geometric models of UAV images were established through a precision sensor modeling algorithm developed in house. Then, a digital map by stereo plotting was produced to evaluate the possibility of large-scale digital map. For this study, images and GCPs were acquired for Ganseok-dong, Incheon and Yeouido, Seoul. As a result of precision sensor modeling accuracy analysis, high accuracy was confirmed within 3 pixels of the average error of the checkpoints and 4 pixels of the RMSE was confirmed for the two study regions. As a result of the mapping accuracy analysis, it satisfied the 1:1,000 mapping accuracy announced by the NGII (National Geographic information Institute). Therefore, the precision sensor modeling technology suggested the possibility of producing a 1:1,000 large-scale digital map by UAV images.