• Journal of the Korea Society of Computer and Information
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• v.20 no.3
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• pp.19-27
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• 2015

Technologies of wind power generation for development of alternative energy technology have been accumulated over the past 20 years. Wind power generation is environmentally friendly and economical because it uses the wind blowing in nature as energy resource. In order to operate wind power generation efficiently, it is necessary to accurately predict wind speed changing every moment in nature. It is important not only averagely how well to predict wind speed but also to minimize the largest absolute error between real value and prediction value of wind speed. In terms of generation operating plan, minimizing the largest absolute error plays an important role for building flexible generation operating plan because the difference between predicting power and real power causes economic loss. In this paper, we propose a method of wind speed prediction using numeric prediction algorithm-based wind speed forecast model made to analyze the wind speed forecast given by the Meteorological Administration and pattern value for considering seasonal property of wind speed as well as changing trend of past wind speed. The wind speed forecast given by the Meteorological Administration is the forecast in respect to comparatively wide area including wind generation farm. But it contributes considerably to make accuracy of wind speed prediction high. Also, the experimental results demonstrate that as the rate of wind is analyzed in more detail, the greater accuracy will be obtained.

• Journal of the Korean Applied Science and Technology
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• v.8 no.1
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• pp.27-34
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• 1991

동백종실유(冬栢種實油)에서 컬럼크로마토그래피로 지질(脂質) 성분(成分)을 상호(相互) 분리(分離)하였다. 여기서 얻은 트리글리세리드의 일부(一部)를 취하여 알칼리로 가수분해(加水分解)하거나 또는 pancreatic lipase로 가수분해(加水分解) 하여, 트리글리세리드의 구성(構成) 지방산(脂肪酸) 또는 1, 3- 위치(位置)와 2-위치(位置)에 급합(給合) 한 지방산(脂肪酸) 조성(組成)을 조사(調査)하였다. 나머지 트리글리세리드는 16% $AgNO_3$ TLC로 이중결합선(二重結合敾)별로 나누었으며, 이렇게 나누어진 분획(分劃)을 다시 HPLC로 PN별로 재분획(再分劃) 하였다. 여기서 얻어진 획분(劃分)들 중 PN이 같은 것은 모두 모아서 알칼리 가수분해(加水分解)로 PN의 총지방산(總脂肪酸) 조성(組成)을, pancreatic lipase로 1,3 위치(位置)에 결합선(結合敾)한 지방산(脂肪酸)의 조성(組成)을 조사(調査) 하였다. 여기서 얻어진 결과(結果)로 부터 구성(構成) 트리그리셀리드 분자종(分子種)을 산출(算出)하였더니 다음과 같은 결과(算出)를 얻었다. 1) 종실유(種實油)는 투명(透明)한 액체(液體)로 그 함량(含量)이 73.5%였으며, 그 중 트리글리세리드가 94.8%, 극성(極性) 지질(極性)이 2.0%, 탄화(炭化) 수소(水素)가 1.8%였다. 2) $AgNO_3$-TLC로 트리글리세리드를 분획(分劃)하였더니 5개의 획분(劃分)을 얻었으며, 대부분(大部分)의 트리글리세리드가 이중(二重) 결합선(結合敾) 3${\sim}$5개인 band 2와 band 3에 80% 이상 존재(存在)하였다. 3) $AgNO_3-TLC$에서 얻은 각 획분(劃分)은 모두가 HPLC상에서 PN 46, 48 및 50으로 나누어졌으며 전체(全體) 분획(分劃)에서 PN 48이 78.13%로 제일 많았으며, 다음으로 PN 50이 12.04%였으며, PN 46이 9.83%였다. 4) 전체(全體) 트리글리세리드 분자종(分子種) 중에서 0.1mol% 이상을 차지하고 있는 분자종(分子種)이 43종(種)이었으며, OOO와 POO가 각각 39.8mol%와 25.8mol%로 제일 많았으며, 그 다음으로 OPO가 5.5 mol%, OOL가 4.8 mol%, POS가 3.9mol%, SOO가 3.5mol%. POL이 3.0mol%였다. 또 동백종실유(冬栢種實油)에 존재(存在)하는 트리글리세리드의 분자종(分子種)의 조성(組成)은 1,3-random, 2-random 분포설(分布說)에 따라 구성(分布說)되어 있었다.

• Journal of Korean Society of Forest Science
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• v.54 no.1
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• pp.60-67
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• 1981

The run-off experiment plots had been established for eight sets of plot comprising four treatments with two replications on $20^{\circ}$ slope land having the Wait-A-Bit Clay soil(locally known), at the Olive River Soil Conservation Centre, Trelawny in Jamaica. The location of plots was about 820 metres m.s.l. and sloped north-west. Each plot size was determined as $40m^2$ having 2.7 m wide and 15.8 m long along slope. All of the run-off soil and water were collected by using the receiving tanks through the collection troughs and conveyance pipes. These run-off materials were measured and sampled, dried and computed for determination of the soil loss from each treatment of plots. During the first period of experiment for about 10 month which was one crop-year cycle of yam crop, total amount of 1,295 mm rainfall received. The heaviest daily rainfall was recorded as 116.2 mm on August 5 followed by 100.4 mm on August 6, 1980. The soil sediment had been collected and analysed for eleven times during this experiment. Total amounts of soil sediment as over-dried weight by the treatment plot were estimated as 182 ton/ha from treatment I, 105 tons/ha from treatment II, 50 tons/ha from treatment III, 43 tons/ha from treatment IV respectively. It is recommendable at present that the treatment III and IV measure which treated with contour mounds with the hillside ditch and grass buffer strip should be adopt4ed for hillside farming particularly with yam cultivation in Jamaica.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.1
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• pp.24-34
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• 2001

The authors reconstruct a mooring type underwater positioning system to measure the movement of bag-net in a set-net by long base line mode with four transponders attached on the bag-net in latitudinal and a transponder fixed on the sea bed. To confirm the practical use of the system, the field experiments were carried out at the Jaran Bay, Kosung, Kyungnam Prov., on October 6, 2000 (neap tide) and November 28, 2000 (spring tide). And the vertical oscillation of bag-net was observed with three data loggers attached on the bottom of bag-net in longitudinal on November 28, 2000. The longitudinal movement range, the latitudinal one and the vertical one of the bag-net were 3.2 m, 3.4 m and 2.1 m. respectively. At the spring tide, these variations were 7.8 m, 7.8 m and 5.0 m, respectively. The vertical oscillation range about the bottom of the bag-net at near point of the slope net, at the middle part and at far point from the slope net were 3.2 m, 3.7 m and 8.4 m, respectively. The depth of the bottom net was decreased and its vertical oscillation appeared frequently when the current speed was more than 10 cm/s and the current direction was significantly different from the longitudinal axis of the bag-net. The variation of hydrophone coordinates measured by the transponder fixed on the sea bed presents that hydrophones equipped to the frame line of the set-net could be moved within several meters due to the tidal current. The fact indicates that the compensation of hydrophone coordinates is necessary to reduce the measuring errors. The position measuring errors of x, y and z axis of the system measured in the cage of aquaculture were 0.6 m, 0.8 m, and 1.2 m, respectively. And the errors of the transponders those were close to the base lines or placed in the baselines were smaller than those of others.

• Korean Journal of Remote Sensing
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• v.36 no.5_4
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• pp.1195-1207
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• 2020

With the development of GeoWeb technology, 2D/3D spatial information services through the web are also has been used increasingly in the application of disaster management. This paper is suggested to construct a web-based 3D geo-spatial information mapping platform to visualize various spatial information collected at the disaster site in a web environment. This paper is presented a web-based geo-spatial information mapping service plan for the various types of 2D/3D spatial data and large-volume LiDAR point cloud data collected at the disaster accident site using HTML5/WebGL, web development standard technology and open source. Firstly, the collected disaster site survey 2D data is constructed as a spatial DB using GeoServer's WMS service and PostGIS provided an open source and rendered in a web environment. Secondly, in order to efficiently render large-capacity 3D point cloud data in a web environment, a Potree algorithm is applied to simplifies point cloud data into 2D tiles using a multi-resolution octree structure. Lastly, OpenLayers3 based 3D web mapping pilot system is developed for web visualization of 2D/3D spatial information by implementing basic and application functions for controlling and measuring 3D maps with Graphic User Interface (GUI). For the further research, it is expected that various 2D survey data and various spatial image information of a disaster site can be used for scientific investigation and analysis of disaster accidents by overlaying and visualizing them on a built web-based 3D geo-spatial information system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.380-390
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• 2020

Cyber-university has a higher rate of dropout freshmen due to various educational factors, such as social background, economic factors, IT knowledge, and IT utilization ability than students in twenty offline-based university. These students require a different dropout prevention method and improvement method than offline-based universities. This study examined the main factors affecting dropout during the first semester of 2017 and 2018 A Cyber University. This included management and counseling factors by the 'Decision Tree Analysis Model'. The Management and counseling factors were presented as a decision-making method and weekly methods. As a result, a 'Dropout Improvement Model' was implemented and applied to cyber-university freshmen in the first semester of 2019. The dropout-rate in freshmen applying the 'Dropout Improvement Model' decreased by 4.2%, and the learning-persistence rate increased by 11.4%. This study applied a questionnaire survey, and the cyber-university students LMS (Learning Management System) learning results were analyzed objectively. On the other hand, the students' learning results were analyzed quantitatively, but qualitative analysis was not reflected. Nevertheless, further study is necessary. The 'Dropout Improvement Model' of this study will be applied to help improve the dropout rate and learning persistence rate of cyber-university.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.633-642
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• 2018

The purpose of this study was to assess the antioxidant, anti-inflammatory and preservative effects of Water Chestnut from 70% ethanol extracts. The toxicity of extracts from Water Chestnut investigated using the RAW 264.7 cell showed higher than 90% of cell survival rate. The total content of polyphenol ethanol extract was $353.1{\pm}5.6mg/g$, while the total content of flavonoid was $26.2{\pm}1.4mg/g$. With a concentration level of $1{\sim}1000 ({\mu}g/m{\ell})$ ethanol extract of Water Chestnut the range of removal of 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radicals was $17.0{\pm}2.8%{\sim}88.6{\pm}0.6%$ respectively and the range of removal of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals was also $2.3{\pm}0.8%{\sim}93.9{\pm}0.2%$ respectively. There were decreases in reactive oxygen species(ROS) generations ethanol extracts of Water Chestnut 1, 10, $100({\mu}g/m{\ell})$ and significance decrease at $100{\mu}g/m{\ell}$ (p<.01). As a result of measuring the Nitric Oxide(NO) generation amount of Water Chestnut extract 1, 10, $100({\mu}g/m{\ell})$ concentration exhibited significant (p<.001, p<.01) decreases. For the anti-bacterial features using a paper disk and the preservative features using petri film, no significance was found and therefore water chestnut extracts had not anti-bacterial or preservative features.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.215-221
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• 2020

Navigation lights used in supersonic aircraft are used to identify the direction and location of the aircraft. The color of the navigation lights and location of installation are defined by aviation law as red for the left wing, green for the right wing, and white for the tail. Navigation lights operate in BRT and DIM modes. BRT is the brightest mode, and DIM is an output with dimmed brightness. Navigation lights serve to prevent aircraft collisions and are very important for stability and location identification. One phenomenon is that the inlet and tail navigation lights flicker abnormally. In this study, fault tree analysis was performed in two stages. The first step was derived from three causal factors, the second step developed five improvements, and the optimal improvement plan was drawn. The navigation lights confirmed that the initial input power was unstable as the main cause of abnormal flickering. As an improved method, the circuit was adjusted to stabilize the initial power, and it was confirmed that flickering did not occur as a result of the tests under the same conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.248-255
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• 2020

The effects of the coating thickness on the thermal durability and thermal stability of thermal barrier coatings (TBCs) with a gradient coating thickness were investigated using a flame thermal fatigue (FTF) test and thermal shock (TS) test. The bond and topcoats were deposited on the Ni-based super-alloy (GTD-111) using an air plasma spray (APS) method with Ni-Cr based MCrAlY feedstock powder and yttria-stabilized zirconia (YSZ), respectively. After the FTF test at 1100 ℃ for 1429 cycles, the bond coat was oxidized partially and the thermally grown oxide (TGO) layer was observed at the interface between the topcoat and bond coat. On the other hand, the interface microstructure of each part in the TBC specimen showed a good condition without cracking or delamination. As a result of the TS test at 1100 ℃, the TBC with gradient coating thickness was initially delaminated at a thin part of the coating layer after 37 cycles, and the TBC was delaminated by more than 50% after 98 cycles. The TBCs of the thin part showed more oxidation of the bond coat with the delamination of topcoat than the thick part. The thick part of the TBC thickness showed good thermal stability and oxidation resistance of the bond coat due to the increased thermal barrier effect.

• Journal of the Korean Applied Science and Technology
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• v.15 no.4
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• pp.1-9
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• 1998

The lipids from the seeds of Pinus koraiensis mostly composed of triacylglycerols (TGs), in which linoleic acid (46.2 mol%) and oleic acid (25.6 mol%) are present as main components in the fatty acid composition. Surprisingly, they also have unusual fatty acids with ${\Delta}^5$-double bond systems such as ${\Delta}^{5.9.12}-C_{18:3}$ (16.0 mol%), ${\Delta}^{5.9}-C_{18:2}$ (2.3 mol%) and ${\Delta}^{5.11.14}-C_{20:3}$ (0.8 mol%). Saturated fatty acids of palmitic, stearic and arachidic acid were present in less than 8.0 mol%. TG was resolved into 17 fractions by reverse-phase HPLC according to so-called partition number (PN) suggested by Plattner, in which TG molecules with ${\Delta}^{5}$-NMDB acyl chains eluted later than did those with ${\Delta}^{9}$-MDB acyl radicals. $Ag^+$-HPLC separated the TG into 14 fractions more clearly than did those with ${\Delta}^{9}$-MDB acyl radicals. $Ag^+$-HPLC separated the TG into 14 fractions more clearly than did reverse-phase HPLC, and the complexity of ${\Delta}^{5.9.12}-C_{18:3}$ moiety with silver ion impregnated in the column bed was in the level between ${\Delta}^{9.12.15}-C_{18:3}$ ($C_{18:3{\omega}3}$) and $C_{18:2{\omega}6}$ (${\Delta}^{9.12}-C_{18:2}$). In the $Ag^+$-HPLC, it was found that the molecular species having a given-numbered double bonds widely spreaded in the acyl chains eluted earlier than those concentrated in one acyl chain. The main molecular species are $(C_{18:2{\omega}6})_2/{\Delta}^{5.9.12}-C_{18:3}$ (14.8 mol%), $C_{18:1{\omega}9}/C_{18:2{\omega}6})_2$ (12.8 mol%) and $C_{18:1{\omega}9}/C_{18:2{\omega}6}/{\Delta}^{5.9.12}-C_{18:3}$ (10.9 mol%).