• Journal of the Korean Association of Geographic Information Studies
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• v.4 no.4
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• pp.72-78
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• 2001

In this study, high spatial resolution of IKONOS 1m image and Red(0.63~0.69) band, NIR(0.76~0.90) band in 4m image, which are the same wavelength range as Landsat TM band 3, 4, were used for extraction of the front areas of B. Xylophilus in Geuje island where is located in southern part of Korea. Moreover, since they have higher spatial resolutions than Landsat TM, they have been used for lots of studies in the field of forest and vegetation. In the results, it was validated by GPS field survey, spectral histogram analysis of IKONOS NIR band was significant available method for extracting the front areas of B. Xylophilus. In this study, 15 points were verified as real damaged trees of 22 sample points extracted from GPS field survey. This study was not only extracted the damaged trees by B. Xylophilus but also suggested the possibility of using IKONOS images for the study on the forest damages by any disease and insect pests.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.295-300
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• 2010

Recently, many tsunamis triggered by impulsive undersea ground motions occurred in subduction zones around the Pacific Ocean area including the East Sea surrounded by Korea, Japan and Russia. The wave height of a tsunami may be in the order of several meters, while the wavelength can be up to 1,000 km in the ocean, where the average water depth is about 4 km. A tsunami could cause a severe coastal flooding and property damage not only at neighboring countries but also at distant countries. A fundamental and economic way to mitigate unusual tsunami attacks is to construct tsunami hazard maps along coastal areas vulnerable to tsunami flooding. These maps should be developed based on the historical tsunami events and projected scenarios. The map could be used to make evacuation plans in the event of a real tsunami assault.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.31-35
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• 2007

In order to find out the cause of plant injury, the symptom of plant injury, and contents of element concerned in the plant were analysed. Also, a case study was conducted to find out the factor of plant injury at a agriculture and industry complex in Gyeongsang province in 2004. The distribution of isomeric curve was made with meteorological data, toxic gas concentration exhausted from pollution source. The general symptom of plant injury by ammonia gas was dry and dead of leaves with white color. At low concentration of ammonia gas, plant leaf showed spots of reddish brown. The characteristic of plant injury symptom by hydrogen fluoride gas was that the symptom was appeared at the edge of leaf. The isomeric curve of sulfur dioxide at the region, where the plant was damaged, showed that the area was affected by exhausted gas from the pollution source. Especially, this area was affected more deeply at summer than any other season.

• Journal of Sericultural and Entomological Science
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• v.28 no.2
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• pp.1-8
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• 1986

This study was conducted to bring light on inducing factors for non-sprouting occured in the mulberry field of Kyungpook Province in 1983. The results are as follws ; 1. In spring, winter buds were suddenly died during germination, necrosis appeared in pholem and cortex of non-sprouting stem and measles at the bottom of non-sprouting stem. 2. The depth of available of soil was more shallow in the non-sproutiong field than in healthy field. 3. There was no signifioant difference between the healthy field and non-sprouting field in siol PH, the content of organic matter, available phosphorous and exchangeble cations. 4. Available boron content in soil was significantly more in healthy field than in non-sprouting field. 5. Boron content in leaf and bark was significantly lower in the non-sproutiong tree than in the healthy tree. 6. The non-sprouting fields were completely controlled by the application of 6kg/10a borax. 7. Cold tolerance of the mulberry tree was higher in the mulberry tree with boron than in the mulberry tree without boron. 8. Mulberry tree in Kyungpook Province in 1983 may absorb water earlier compared with the average year because of high temperature at the end of March, 1983 and they had been damaged by frost injuary due to the lowest temperature (-6.4$^{\circ}C$) on the grass at the beginning of April 1983. As the above results, non-sprouting bud in the mulberry fields of Kyungpook Province in 1983 had been occured by low temperature and boron deficiency and boron deficiency of mulberry trees accelerared the frost injury.

• Journal of Bio-Environment Control
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• v.20 no.1
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• pp.45-49
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• 2011

This research was carried out to investigate frost damage of mulberry tree (Morus alba) according to topographic characteristics in Buan province. The first bud-break, leafing, blooming and harvest date of mulberry tree in 2010 were two, four, fourteen and eight days later than those in 2009, respectively. These results were that daily mean temperature during March and April in 2010 were lower than those in 2009 by $2.3^{\circ}C$ and $2.4^{\circ}C$. Frost damage of orchards at flat-bottomed valley, flat near hill and lake, and plain were 50.0%,12.0%, and 4.2%, respectively. Also, frost damage of branch of below 15 mm in diameter was serious than that of branch over 16 mm, but orchard at flat-bottomed valley was high as the range of 46.2~54.0%. These results in 2010 were caused by occurrence of below zero temperatures in leafing stage. Since then, many shoots came out at accessary bud on proximal and the top part of the branches. Therefore, frost damage of mulberry tree in Buan province in 2010 was caused by occurrence of below zero temperatures on April and topographic characteristics of orchard.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.4
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• pp.1-13
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• 2009

Liquefaction is a significant threat to structures on loose saturated sandy soil deposits in the event of an earthquake, and can often cause catastrophic damage, economic loss, and loss of life. Nevertheless, the Korean peninsula has for a long time been recognized as a safe region with respect to the hazard of liquefaction, as the peninsula is located in a moderate seismicity region, and there have been no reports of liquefaction, with the exception of references in some historical documents. However, some earthquakes that have recently occurred in different parts of the world have led to liquefaction in non-plastic silty soils, a soil type that can be found in many of the western coastal areas of Korea. In this study, we first present procedures for evaluating the liquefaction potential, and calculate the liquefaction potential index (LPI) distribution at two western coastal sites using both piezocone penetration test (CPTu) data and standard penetration test (SPT) data. The LPI is computed by integrating liquefaction potential over a depth of 20m, and provides an estimate of liquefaction-related surface damage. In addition, we compared the LPI values obtained from CPTu and SPT, respectively. Our research found that the CRR values from CPTu were lower than those from the SPT, particularly in the range between 40 and 120 for the corrected tip resistance, (qc1N)CS, from the CPTu, or in the range of CRR less than 0.23, resulting in relatively high LPI values. Moreover, it was observed that the differences in the CRR between the two methods were relatively higher for soils with high fine contents.

• Korean journal of applied entomology
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• v.40 no.4
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• pp.301-307
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• 2001

The pine needle gall midge (PNGM), Thecodiplosis japonensis Uchida et Inouye, is a serious pest in pine forests in Korea. Since the first report of PNGM infestation in Korea in 1929, the infestation area has been expanded gradually. In 1975 the distribution of PNGM and its parasitoids were surveyed throughout several infested areas in Korea. Annual survey has been made for the rates of gall formation by PNGM and parasitism by its parasitoids at the monitoring sites including newly infested area in 1975 since 1980. These data were used to examine the relationship between PNGM and its parasitoids for newly invaded areas. The gall forming rate of PNGM and the parasitism by the parasitoid were 34.8 and 1.9% in 1975, respectively, while the gall forming rate and the parasitism were 20.7 and 8.9% in 1985, respectively. The relationships of densities between PNGM and its parsitoid were weak in the early stage of dispersion, but the density of parasitoid was with an asymptotic increase along with PNGMs density increase during the observation period for 10 years.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.863-868
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• 2009

최근에 이상기후로 인해 예측하기 힘든 기상현상들이 돌발적이고 대규모의(또는 설계빈도를 초과하는) 집중호우를 야기하여 댐과 같은 수공구조물의 안전을 위협하고 있다. 그러므로 이러한 대규모의 집중호우로 발생되는 댐의 붕괴에 대한 대책을 수립하는 것이 매우 중요하다. 특히 댐의 붕괴가 도시의 침수로 이어지는 경우는 더욱 많은 인명과 재산피해를 발생시키므로 도시지역을 흐르는 범람홍수파의 특성에 대한 규명은 매우 중요하다. 본 연구에서는 홍수범람파의 특성을 3차원 수치모형인 FLOW-3D를 이용하여 모의하였다. 저류 수심 0.4m, 두께 0.8m의 댐이 붕괴하여 붕괴폭이 1m가 된다고 가정하였고, 도시지역은 댐으로부터 5m 거리에 위치한다고 가정하였다. 대상 도시지역은 $0.3m{\times}0.3m{\times}0.6m$($L{\times}W{\times}H$)인 정사각형 블록들을 $5{\times}5$ 정방향으로 배치하였고, 수리실험 결과와 비교 검증하였다. 그리고 범람홍수파가 흐름방향과 일치하게 접근해오는 경우와 도시지역으로의 접근각도에 따른 범람홍수파의 변화를 보기위해 흐름방향에 대하여 각각 $10^{\circ}$, $22.5^{\circ}$, $45^{\circ}$ 회전시킨 경우에 대해 수치모의를 수행하였다. 그리고 각 경우의 침수영향들을 비교하여 그 차이점을 분석하였다. 모의 결과 범람홍수파의 접근각도가 흐름방향에 대해 커질수록 도시선단에서 도수는 적게 일어났고 유속도 감소하였으며, 수심은 증가하였다. 본 연구의 결과를 토대로 범람홍수파가 흐름방향과 일치하게 접근해 올 때가 가장 위험한 case 라는 것을 알 수 있다. 이 결과는 추후 유체-구조물간의 연성해석을 통하여 범람 홍수파의 흐름이 건물에 주는 영향까지 파악한다면 예방대책 수립의 보다 더 정확한 기초자료로 활용할 수 있을 것이다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.93-93
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• 2022

최근 이상기후로 인하여 우리나라 산림에 태풍 및 국지성 호우가 빈번히 발생하고 있다. 이로 인해 사면재해가 많이 발생하고 있으며 그 중 호우로 인한 많은 양의 물과 함께 토석 및 부유물이 중력에 의해 경사면을 따라 흐름 형태를 보이는 토석류 재해는 속도가 매우 빠르고 파괴적이며 그 결과는 비참하기까지 하다. 더구나 인구밀도가 낮은 산지 계곡부 뿐만 아니라 도시지역에서도 토석류 재해가 빈번히 발생하며 국내 및 해외에서도 토석류에 의한 피해사례는 자주 볼 수 있다. 이러한 토석류 재해의 피해를 줄이고자 토석류의 유동성을 저감시키기 위한 대책구조물의 시공이 많이 이루어지고 있으며 최근에는 투과형 구조물 중 하나인 원통형 기둥구조물을 그룹 형태로의 시공하는 경우가 늘어나고 있다. 토석류와 대책구조물 간의 상호작용은 월류(overflow), 쳐오름(run-up), 역류(backwater) 등의 복잡한 흐름 거동을 보인다. 하지만 원통형 대책구조물에 대한연구가 많이 이루어져 있지 않고 대규모 실험 또한 비용이 많이 소요되고 실행하기도 어렵다. 이 연구는 오픈소스 소프트웨어인 OpenFOAM을 사용하여 원통형 대책구조물의 설치 조건에 따라 토석류 흐름에 미치는 영향을 분석하였다. 짧은 시간 내에 흐름이 발생하고 비뉴튼 유체 특성을 갖는 토석류의 유효전단응력이 난류전단응력에 비해 상당히 크므로 난류의 영향은 무시하였다. 계산된 수치모의의 결과를 같은 규모로 시행한 실험결과와 비교분석 및 검증하였다. 공학학적 문제에 적용 가능하도록 비교적 낮은 해상도의 계산 격자를 사용했지만 실험에서 보여지는 토석류의 흐름거동을 양호하게 재현했으며 원통형 대책구조물의 배치조건에 따라 토석류 선단부 유속의 감소 정도 및 시간에 따른 흐름깊이 변화를 분석할 수 있었다. 이 연구는 다양한 조건을 가지는 토석류 흐름을 해석하는데 유용하게 활용할 수 있으며, 추후 복잡한 실제지형 조건을 고려하는 연구를 통하여 적용성을 확보하고자 한다.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.109-115
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• 1984

This study was conducted to investigate the bionomics, host range and damage aspect of Japanese juniperus bark borer, Semanotus bifasciatus M., which shoves the severe damage for the Juniperace in Chonnam province, recently. Host plants were Juniperus virginiana, J. chinensis var. kaizuka, J. chinensis, Biata orientalis var. nepalensis, Chamaccyparis ostus and Thujopsis dolabrata. Out of those, J. chinensis var. kaizuka is newly investigated in this study. Damage rate in each area was $16.5\%$ in Kwangju, $4.25\%$ in Damyang ana $6.5\%$ in Hwasoon. Adults appear once a year, with a peak at late March to early April. Adults emergence during the day showed the peak at 13 to 15 hours and were influenced in the maximum temperature in a day. Attack direction of larva after invasion in the stem was $62\%$ toward base, $22\%$ toward tip and $16\%$ toward horizon, and the damage in each DBH (Diameter of breast height) was the greatest at $30\~40mm$. At period of each stage, egg was $15.8\~19.7$ days, larva was $l12\~126$ days and pupa was $15\~21$ days. Longevity of adult was 19 days for female and 16 days for male.