• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1149-1151
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• 2003

We performed a validation study of the MODIS active fire detection algorithm using high resolution SPOT image as the reference data set. Fire with visible smoke plumes are detected in the SPOT scenes, while the hotspots in MODIS data are detected using NASA's new version 4 fire detection algorithm. The detection performance is characterized by the commission error rate (false alarms) and the omission error rate (undetected fires). In the Sumatra and Kalimantan study area, the commission rate and the omission rate are 27% and 34% respectively. False alarms are probably due to recently burnt areas with warm surfaces. False negative detection occur where there are long smoke plumes and where fires occur in densely vegetated areas.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.179-185
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• 2008

The purpose of this paper is to propose a systematic method on the weld pitch design of a vehicle sub-frame considering the fatigue life of spot welding points. The input data, which perform the fatigue analysis on the spot welding nuggets, are obtained by both the dynamic analysis of the multi-body vehicle model passing through the virtual proving ground of a typical Belgian road and the quasi-static analysis with the finite element model of the vehicle sub-frame. By utilizing the life cycle data obtained from the fatigue analysis, the welding points to perform the pitch change are determined. The sensitivity analysis on the fatigue life of the welding points is carried out by using the three-level orthogonal array design, and through the results of the sensitivity analysis, the best combination on the welding pitch is determined. This study shows that as compared with the baseline design, the sub-frame redesigned by the proposed technique improves the fatigue life about 7 percent while reducing the number of welding points about 19 percent.

• Korean Journal Plant Pathology
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• v.3 no.4
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• pp.285-290
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• 1987

Septoria brown spot caused by Septoria glycines Hemmi is one of the serious fungal diseases in soybean. Since little has been known about the disease progress in the field, the present study was conducted to determine the factors affecting the disease progress in the soybean plant. Disease severity and pattern of the progress of the Septoria brown spot were different with varieties. Susceptibility of soybean plants increased with increase of plant age and leaf maturity in order from the primary leaf to the newly expanded leaf. It seemed to be related with conidial germination on the leaves. Germination and germtube elongation were more inhibited by the diffusates obtained from upper leaves than those from lower leaves and they were higher in a susceptible variety than in a moderately resistant one.

• 한국지형공간정보학회:학술대회논문집
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• 2002.03a
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• pp.27-33
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• 2002

최근 들어 다항식비례모형(RFM: Rational Function Model)은 비전문가에게 있어서 지형보정을 위한 정확도 문제를 해결함과 동시에 센서 종류에 상관없이 적용 가능한 범용적인 센서모델링 기법으로 각광을 받고 있다. 그러나 엄밀(physical) 모델이 없는 센서 혹은 위성의 궤도력 자료를 제공하지 않는 센서의 경우 다항식비례모형의 적용을 위해서는 다수의 매개변수 사용으로 인한 계수들 간의 상관성을 고려해야 한다. 이에 본 연구에서는 2차 다항식비례모형에 기초하여 전방 다항식비례모형(Forward RFM)과 상관도 분석을 통한 전방 다항식비례모형의 이른 및 위치정확도에 관한 연구를 수행하였다. 대상연구지역은 KOMPSAT(Korea Multi-Purpose Satellite)과 SPOT으로 촬영한 대전광역시와 그 주변지역으로 SPOT과 KOMPSAT 모두 상관성 분석 전에는 대략 50% 정도의 검사점에 대해 과대오차(>100m)가 얻어졌으며, 이 점들을 제외한 검사점에 대해서도 SPOT은 평균수평오차 20-24m, 평균표고오차 25m, KOMPSAT은 평균수평오차 15-24m, 평균표고오차 30m를 나타내었다. 전방 다항식비례모형에 대하여 상관성 분석을 수행한 후에는 검사점에 대한 모든 과대오차 조정결과가 소거되었고 검사점에 대해서 SPOT은 평균수평오차 8.8m, 평균표고오차 25.2m, KOMPSAT은 평균수평오차 8.4m, 평균표고오차 14.5m를 나타내었다. 최종적으로 연구지역에 대한 수치표고모형의 제작을 통해 상관도 분석을 통한 다항식비례모형의 실제 적용 가능성을 보여주었다.

• The Plant Pathology Journal
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• v.17 no.3
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• pp.180-183
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• 2001

A corynespora leaf spot of pepper, which has not been reported previously in Korea, occurred severely at the major pepper cultivation area of Chinju, Gyeongnam province in 2001. Infection rate ranged from 48.2 to 84.7% in eight fields surveyed. The causal fungus was identified as Corynespora cassicola based on the following cultural and morphological characteristics. The fungi grew well on potato dextrose agar, showing gray to brown color with cultural age. Conidia formed solitary or catenary were obclavate to cylindrical in shape, and pale olivaceous brown or brown in color. They had 420 pseudoseptate and isthmus, and measured 42.7-197.6 x 9.3-$23.5\mu\textrm{m}$. Septate conidiophores were pale to light brown in color, and measured 116.5-836.0 x 4.2-$11.0\mu\textrm{m}$. Conidia germinated as a bi-polar type. Optimal temperature for mycelial growth and conidial germination was $30^{\circ}$ and 25-$30^{\circ}$, respectively. The fungus showed strong pathogenicity to pepper plant, and the symtoms on pepper by the artificial inoculation were similar to those observed in the field. This is the first report on the corynespora leaf spot on pepper (Capsium annuum) caused by Corynespora cassicola in Korea.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.397-401
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• 1998

Asexual spores of Mycosphaerella nawae were profusely produced on PDA after a prolonged incubation at $25^{\circ}C$ for 90 days. When persimmon trees were artificially inoculated by the conidial suspension, typical symptoms of circular leaf spot of persimmon appeared on the leaves two month later. The imperfect stag of the fungus was identified as Ramularia sp. based on following morphological characteristics examined under a light microscope and a scanning electron microscope. Conidia were mostly ellipsoid, but occasionally cylindrical, elongated oval, taro, peanut or gourd shapes and measured as 12.2~32.6$\times$6.1~10.2 ${\mu}{\textrm}{m}$. erect, hyaline, colorless-light brown. Conidia were formed solitarily or in chains on a medium and infected leaves. Conidiophore was erect, hyaline, colorless-light brown. and the size was 20.4~102.0$\times$3.1~10.2 ${\mu}{\textrm}{m}$, respectively. In this paper, we firstly demonstratrated that asexual spores of M. nawae induced persimmon circular leaf spot in nature as well as sexual spores of the fungus. Therefore, it is hypothesized that the imperfect stage of the fungus plays an important role in nature for epidemics as secondary inoculum.

• Journal of Welding and Joining
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• v.20 no.6
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• pp.78-78
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• 2002

Front-side members are structures with the greatest energy absorbing capability in a front-end collision of vehicles. This paper was performed to analyze initial collapse characteristics of spot welded hat and double hat-shaped section members, which are basic shape of side members, on the shift of flange weld pitches. The impact collapse tests were carried out by using home-made vertical air compression impact testing machine, and impact velocity of hat-shaped section members is 4.17m/sec and that of double hat-shaped section members is 6.54m/sec. In impact collapse tests, the collapsed length of hat-shaped section members was about 45mm and that of double hat-shaped section members was about 50mm. In consideration of these condition, axial static collapse tests(0.00017m/sec) of hat and double hat-shaped section members were carried out by using UTM which was limited displacement, about 50mm. As the experimental results, to obtain the best initial collapse characteristics, it is important that stiffness of vehicle members increases as section shapes change and the progressively folding mode induces by flange welding pitch.

• Journal of Welding and Joining
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• v.20 no.6
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• pp.802-808
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• 2002

Front-side members are structures with the greatest energy absorbing capability in a front-end collision of vehicles. This paper was performed to analyze initial collapse characteristics of spot welded hat and double hat-shaped section members, which are basic shape of side members, on the shift of flange weld pitches. The impact collapse tests were carried out by using home-made vertical air compression impact testing machine, and impact velocity of hat-shaped section members is 4.17m/sec and that of double hat-shaped section members is 6.54m/sec. In impact collapse tests, the collapsed length of hat-shaped section members was about 45mm and that of double hat-shaped section members was about 50mm. In consideration of these condition, axial static collapse tests(0.00017m/sec) of hat and double hat-shaped section members were carried out by using UTM which was limited displacement, about 50mm. As the experimental results, to obtain the best initial collapse characteristics, it is important that stiffness of vehicle members increases as section shapes change and the progressively folding mode induces by flange welding pitch.

• International Journal of Advanced Culture Technology
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• v.3 no.1
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• pp.145-152
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• 2015

The article aims to apply a friction stir spot welding for producing the lap joint between AA5052 aluminum alloy and C11000 copper alloy. The dimension of the materials was 100 mm in length, 30 mm in width and 1.0 mm in thickness. The copper plate was set overlap the aluminum plate by 30 mm. The welding parameter was the rotating speed of 2500-4000 rpm, the pin inserting rate of 2-8 mm/min and the holding time of 6 sec. The mechanical properties test and the microstructure investigation were performed to evaluate the lap joint quality. The summarized results are as follows. The friction stir spot welding could produce effectively the lap joint between AA5052 and C11000 copper. Increase of the rotating speed and holding time directly affected to decrease the tensile shear strength of the lap joint. The optimized welding parameters in this study that indicated the tensile shear strength of 864 N was the rotating speed of 3500 rpm, the pin inserting rate of 6 mm/min and the holding time of 4sec. The experimental results also showed that the hardness of the weld metal was lower than that of the base materials.

• Journal of Welding and Joining
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• v.23 no.4
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• pp.59-65
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• 2005

The resistance spot welding is one of the most commonly used welding process for joining the sheet metal in automotive manufacturing process due to higher deposition rates and higher economy achieved. Control variables in the resistance spot welding for achieving high quality are welding current, welding force and welding time. Generally at the manufacturing scene, welding current Vs welding time lobe diagram is used to estimate weldability because controlling welding force is not practical due to economical reasons. However new automotive steel plates have been developed to make lightweight automobiles and to improve resistance against rusting. Also the weldability of these steel plates are worst than the existing steel plates because of changing bare metal and surface plating effect. In consequence of above mentioned reasons, it is necessary to use welding force to present the lobe diagram. In this study, we obtained the welding force Vs welding current lobe diagram for commonly used GA steel plate and found that the second order repression model of tensile shear strength was useful in reducing the number of experiments, and the indentation, and thickness change during welding were used as a response to estimate quantitatively expulsion.