• Journal of Environmental Science International
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• v.11 no.10
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• pp.1081-1087
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• 2002

This study was performed to research the characteristics of suspended particulate for Yellow Sand of January, 1999 in Busan. Yellow Sand frequency during 13 years(1988~2000) in Busan showed maximum in April(57%), next to March(21%), May(16%). According to result of 850hPa weather map and backward isentropic trajectory, this event originated from the Gobi Desert and the Loess Plateau of China. And three mode was found in time series of TSP and PM10 concentration, primary peak showed the maximum hourly concentration at ali station. Gamjeondong as industrial site showed the highest TSP concentration and also had the longest high concentration($geq700\mu\textrm{g}/m^3$). In PM10, concentration of primary peak showed maximum value at Yeonsandong, maximum concentration of secondary and third peak was Deokcheondong. Lasted time from primary peak to secondary peak was about 30 hours, between secondary peak and third peak was 18 hours in Busan, The traveling time between occurrence of Yellow Sand the finding of it was 8~9 hours in Busan and 4~5 hours in central area.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.533-539
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• 2018

In this paper, the transformer type superconducting fault current limiter (SFCL) with additionally coupled circuit was suggested and its peak fault current limiting characteristics due to the fault condition to affect the fault current were analyzed through the fault current limiting tests. The suggested transformer type SFCL is basically identical to the previous transformer type SFCL except for the additional coupled circuit. The additional coupled circuit, which consists of the magnetically coupled winding to the primary and the secondary windings together with another superconducting element and is connected in parallel with the secondary winding of the transformer type SFCL, is contributed to the peak fault current limiting operation for the larger transient fault current directly after the fault occurrence. To confirm the fault current limiting operation of the suggested SFCL, the fault current limiting tests of the suggested SFCL were performed and its effective peak fault current limiting characteristics were analyzed through the analysis on the electrical equivalent circuit.

• Korean journal of applied entomology
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• v.44 no.4 s.141
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• pp.337-339
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• 2005

In Iksan, Korea, Parnara guttata Brener et Grey spend three generations per year, 1st generation adult emerged mid to late May from pupa developed from overwintered larva in weeds on bank around rice paddy field or on hillside and moved to rice paddy field to lay eggs on leaves of rice. The damage to rice by 2nd generation larva began to increase late July and reached peak from mid to late August. The 3rd generation adults were observed early to mid September and flew away from rice paddy field. There was significant relationship between the transplanting time and the occurrence of P. guttata in rice paddy fields. P. guttata preferred the rice transplanted in late season in paddy field. Insecticide treatment on late July about a week before the peak larval occurrence reduced the damage by P. guttata up to 91.2%, whereas the treatment on early August was a lot less effective reducing only 57.2% of the damage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.775-784
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• 2023

In terms of flood management, it is necessary to analyze quantitative rainfall and runoff from a spatial and temporal perspective and to analyze runoff for heavy rainfall events that are concentrated within a short period of time. The simulation and analysis results of rainfall-runoff models vary depending on the type and input data. In particular, rainfall data is an important factor, so calculating areal mean rainfall is very important. In this study, the areal mean rainfall of the Samcheok Osipcheon(Riv.) watersheds located in the mountainous terrain was calculated using the Arithmetic Mean Method, Thiessen's Weighting Method, and the Isohyetal Method, and the rainfall-runoff results were compared by applying the distributional model S-RAT and the lumped model HEC-HMS. The results of the temporal transferability study showed that the combination of the distributional model and the Isohyetal Method had the best statistical performance with MAE of 64.62 m³/s, RMSE of 82.47 m³/s, and R² and NSE of 0.9383 and 0.8547, respectively. It is considered that this study was properly analyzed because the peak flood volume occurrence time of the observed and simulated flows is within 1 hour. Therefore, the results of this study can be used for frequency analysis in the future, which can be used to improve the accuracy of simulating peak flood volume and peak flood occurrence time in mountainous watersheds with steep slopes.

• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.27-35
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• 2007

Seasonal occurrences of tobacco cutworm, Spodoptera litura and beet armyworm, Spodoptera exigua were observed using sex pheromone traps at different locations and climatic regions in Yeongnam district. In Gyeongnam province, S. litura male adults kept occur from mid or late March to mid or late November Whereas in Gyeongbuk province, S. litura occurred from mid or late April to early or mid November with exception at Uljin where it was late May to late October. According to the climatic regions, the peak occurrence of S. litura was middle September at the southern coast region, late August at the inland and the basin region, middle August at the inland mountainous region, and early September at the eastern middle coast region. The occurrence rate of S. litura was the highest at Jinju with 20.0% and the lowest at Changyeong with 8.6% in Cyeongnam province, while it was the highest at Sungju with 3.3% and the lowest at Uljin with 0.8% in Gyeongbuk province. In accordance with the climatic regions, the occurrence rate of S. litura was the highest at the inland region with 43.7%, and followed by the southern coast region (36.3%), the basin region (8.4%) and the inland mountainous region (7.0%), and was the lowest at the eastern middle coast legion with 4.6%. On the other hand, S. exigua occurred from early March to middle November with the exception of the eastern middle coast region including Pohang, Yeongdeog and U]ien in Cyeongbuk province where it occurred from mfd April to middle November. The peak occurrence of s. exigua was early August at the inland region, the basin region and the inland mountainous region, and was late of August at the southern coast region and the eastern middle coast region. The occurrence of S. exigua was the highest at Changyeong with 1.6% and the lowest at Busan with 0.4% in Gyeongnam province, while it was the highest at Sungju with 37.2% and the lowest at Uljin with 2.7% in Gyeongbuk province. The climatic regional occurrence rate of S. exigua was the highest at the basin region with 54.3%, and followed by the inland mountainous region (29.9%), the eastern middle coast region (9.3%) and the inland (3.9%), and was the lowest at the southern coast region with 2.6%. As a whole, S. litura occurred more in Gyeongnam province than Cyeongbuk province, while S. exigua occurred more in Gyeongbuk province than Gyeongnam province. According to the regions grouped by climatic differences, the occurrence of S. litura and S. exigua was the highest at the inland region in Gyeongnam province and at the basin region in Gyeongbuk province. The total number of S. litura captured by sex pheromone trap was 2.4 times higher than that of S. exigua. However, the first occurring time and the peak occurrence of S. exigua were slightly earlier than those of S. litura.

• Proceedings of the KSRS Conference
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• v.2
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• pp.938-941
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• 2006

Satellite synthetic aperture radar (SAR) images from 1995 to 2001 and field measurements of sea surface wind, sea state, and vertical stratification are used for statistical analyses of internal wave (IW) occurrence and SAR imaging conditions in the northern South China Sea (NSCS). Latitudinal distribution of IW packets shows that 22% of IW packets distributed in the east of $118^{\circ}E$ and 78% of IW packets in the west of $118^{\circ}E$. The yearly distribution of IW occurrence frequencies reveals an interannual variability. The monthly SAR-observed IW occurrence frequencies show that the high frequencies are distributed from April to July and reach a peak in June. The low occurrence frequencies are distributed in winter from December to February of next year. These statistical features are explained by solitary wave dynamics.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.229-233
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• 1995

The life history, seasonal occurrence of larval population and natural enemies of Tea leaf roller (Caloptilia theivora (Walshingham) were investigated in field-age. C. theivora had 6 generations a year. The developmental periods from egg to adult emergence were 32.1~38.6 days in spring and fall, and 24.8~32.7 days in summer. The average longevities of adults were 8.4~14.5 days in spring and fall, and 6.3~8.6 days in summer. The average number of eggs laid by a female were 55~71 throughout the season. Larval population density of C. theivora showed 3~4 peaks from middle may in 1992 and 1993. However, population density of 194 was pretty low in early season and exhibited a peak in late September-early October. C. theivora overwintered in pupal stage on the leaves. Four hymenopterous parasitoids of C. theivora larvae were identified ; they are Stenomesius japonicus (Ashmead), Sympiesis ringoniellae Kamijo, Elasmus sp., and S. dolichogaster Ashmead which is dominant.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.45.2-45.2
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• 2016

In this study we investigate 195 spacecraft anomalies from 1998 to 2010 from Satellite News Digest (SND). We classify these data according to types of anomaly : Control, Power, Telemetry etc. We examine the association between these anomaly data and daily peak particle (electron and proton) flux data from GOES as well as their occurrence rates. To determine the association, we use two criteria that electron criterion is >10,000 pfu and proton criterion is >100 pfu. Main results from this study are as flows. First, the number of days satisfying the criteria for electron flux has a peak near a week before the anomaly day and decreases from the peak day to the anomaly day, while that for proton flux has a peak near the anomaly day. Second, we found a similar pattern for the mean daily peak particle (electron and proton) flux as a function of day before the anomaly day. Third, an examination of multiple spacecraft anomaly events, which are likely to occur by severe space weather effects, shows that anomalies mostly occur either when electron fluxes are in the declining stage, or when daily proton peak fluxes are strongly enhanced. This result is very consistent with the above statistical studies. Our results will be discussed in view of the origins of spacecraft anomaly.

• Korean journal of applied entomology
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• v.56 no.2
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• pp.97-105
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• 2017

An investigation was conducted to determine the characteristics of seasonal occurrences and effective insecticides for minimizing the occurrence of Pseudaulacaspis cockerelli in sweet persimmon orchards. Most of the nymphs or female scales that mated in mid-September overwintered on twigs, matured to lay eggs in the next spring in accordance with temperature increase, and survived till mid to late May to lay all of their eggs. Males mostly died after mating by the end of September, while the males on the fallen leaves died during the hibernating period. Egg laying in P. cockerelli showed differences in accordance with the weather conditions in each year. They laid eggs from mid-April to mid- or late May, with a peak in early or mid-May. A female was estimated to lay 160 eggs; eggs hatched a week later from the peak period of egg laying. In summer, egg laying started in early or mid-July and ended in mid- or late August, with a peak in late July or early August; a female laid approximately 130 eggs in summer. The estimated egg period was 4 days. The first generation nymph that hatched from the eggs laid by the overwintered female on twigs showed 10% occurrence on twigs and 90% on leaves. The first generation nymphs on twigs mostly developed into female scales. The occurrence of the second generation nymphs reached a peak on July 27, 2009; they lived on the twigs as their overwintering site from mid- or late August. The female and male scales on leaves developed at the similar rate as the first generation nymphs up to August. The occurrence of male scales indicated that the peak occurrence of nymphs was on August 12, 2009, male scales on August 27, and adults approximately on September 14, which showed steady relationship in the sequence of development from nymphs to adult males. Among the nymphs that occurred on the leaves on August 12, 75% of them emerged into male adults, mated, and died. Buprofezine+dinotefurn (20+15) WP treatment on June 9 and 16 resulted in 90.6% control of P. cockerelli, when mortality was checked 7 weeks after treatment.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.261-263
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• 1994

This paper deals with the on off arc characteristics of electromagnetic relay contacts contaminated by NaCl and $H_2SO_4$. In this paper, I have studied the characteristics of on-off voltage waveform. the contact errosion, contact surface analysis by SEM and EDAX under changed R-L parameter of testing circuit. After considers these result, I have tried to promote the diagnosis method and developed the contacts. As a results, (1) The arc duration and the numbers of arc occurrence characteristics are depended on contamination degree. The contamination degree is high when the arc characteristics is high. (2) Under clean condition, arc occurrence voltage, surge peak voltage, arc duration and the rate of contact errosion is lower than wet condition. (3) Surge peak voltage and arc duration is depended on L parameter. When L is High, the arc characteristics is high.