Generally the non-bearing walls in apartment buildings in Korea are not considered as a lateral force resisting members for the design consideration. This engineering practice caused large crack damages and brittle fractures of the non-bearing walls when subjected to Pohang earthquakes in 2017 since those have not been designed for seismic loading. In this study, finite element analysis was conducted for slot type non-bearing wall connection system to reduce damages and concentrate damages to the designated damping device through separation from the structural wall members. Steel plate and dowel bar systems designed for the dissipation of seismic energies were modeled and analyzed to investigate the damage reductions. Finally, the test result and the analysis result were compared and verified.

Earthquake preparedness has become more important with recent increase in the number of earthquakes in Korea, but many existing structures are not prepared for earthquakes. There are various types of liquefaction prevention method that can be applied, such as compaction, replacement, dewatering, and inhibition of shear strain. However, most of the liquefaction prevention methods are applied before construction, and it is important to find optimal methods that can be applied to existing structures and that have few effects on the environment, such as noise, vibration, and changes in underground water level. The purpose of this study is to estimate the correlation between the displacement of a structure and variations of pore water pressure on the ground in accordance with the depth of the sheet file when liquidation occurs. To achieve this, a shaking table test was performed for Joo-Mun-Jin standard sand and an earth pressure, accelerometer, pore water pressure transducer, and LVDT were installed in both the non-liquefiable layer and the liquefiable layer to measure the subsidence and excess pore water pressure in accordance with the time of each embedded depth. Then the results were analyzed. A comparison of the pore water pressure in accordance with Hsp/Hsl was shown to prevent lateral water flow at 1, 0.85 and confirmed that the pore water pressure increased. In addition, the relationship between Hsp/Hsl and subsidence was expressed as a trend line to calculate the expected settlement rate formula for the embedded depth ratio.

The Asian corn borer, O. furnacalis (Crambidae) and the old world bollworm, H. armigera (Noctuidae) simultaneously cause ear damage in corn in Suwon area. It has been assumed that the second generation of larvae of both insects is responsible for the damage. We, therefore, studied proper spray timing of insecticide in order to reduce the damage. A waxy corn hybrid cultivar, Ilmichal, was sown directly on four plots of a field at April 10, April 20, May 4, and May 18, 2018, respectively. A sodium channel blocker, indoxacarb, was sprayed eight times at 3- or 4-day intervals around the silking stage of corn in each sowing plot. At ear harvest time of each plot, we investigated damaged ratio and length of ear, and the numbers of both insect species. The significantly effective spray timings on reduction of ear damage were the sprays at June 29 and July 2 in the plot sown at April 10, the sprays from July 2 to 13 in the April 20-sown plot, the sprays from July 2 to 19 in the May 4-sown plot, and the sprays at July 19 in the May 18-sown plot, respectively. The damage level was positively related to the insect number. The result indicated that the spray at the silking stage of corn was effective on reduction of ear damage. It was assumed that occurrence time of neonate larvae of the insects at silking stage cause the damage, based on the experimental results using screened pots inoculated with the two species.

Free radicals originate due to the radiolysis of cytoplasmic water with low “Linear Energy Transfer” (LET) radiations. Naringenin (Ng) is a natural antioxidative compound found in citrus fruits. This study revealed that Naringenin (Ng) reduced the radiation damage of critical organs by scavenging oxidative free radicals. In the study, Ng was orally administrated to rats daily for 7 consecutive days, prior to whole body exposure to gamma-rays. The scavenging efficacy was evaluated biochemically by measuring the concentration of cytotoxic byproducts and the activity of enzymes relevant to oxidative free radicals, after extracting the organs from the exposed rat. We observed increased levels of malondialdehyde (MDA) concentration, and decrease in the activities of superoxide dismutase (SOD) and catalase (CAT) in the exposed control group. However, pretreatment with Ng significantly reduced the MDA concentration, and increased the activities of SOD and CAT, as compared to the control group, due to the free radical scavenging by Ng. The results indicate that Ng administration prior to irradiation could protect critical organs from radiation damage.

톱다리개미허리노린재 (Riptortus pedestris) 상용 집합페로몬을 이용하여 포획할 때 유인되어지는 거리를 규명하고 이를 이용한 대량포획으로 콩 피해 경감 효과를 조사하였다. 집합페로몬 트랩의 재포획 비율은 최초 방사 지점에서 40 m 이내의 트랩에서는 전체 재포획 개체의 76.1%, 80 m 이내에서는 89.0%가 포획 되었으며, 트랩 설치 방위 간에 재포획 개체수는 큰 차이가 없었다. 대량 포획을 통한 피해 경감 효과를 알아보기 위해 집합페로몬 트랩을 농가 포장에 설치한 결과, 트랩수가 증가 할수록 톱다리개미허리노린재 총 포획수는 직선적으로 증가하였다. 페로몬 트랩 당 포획 할당 면적이 770 m2인 포장에서 10주당 수량이 261.8 g 으로 가장 높았으나, 트랩 당 할당 면적과 수량과의 관계에는 일정한 경향이 없었다. 트랩 당 포획 할당 면적에 따른 종자 형태 비율은 트랩 당 포획 할당 면적이 385 m2와 770 m2 인 포장에서 건전한 A형 종자의 비율이 62% 근처로 높았고 약한 피해립인 B형 종자의 비율이 27% 근처로 가장 낮았다. 톱다리개미허리노린재 집합페로몬 트랩을 이용한 피해 경감 효과는 포장 면적 385∼770 m2 당 1개를 포장 주변에 적절히 설치 운용 한다면 건전립의 비율을 높이고 약한 피해립의 비율을 어느 정도 감소시킬 수 있는 수단으로 사용할 수 있을 것으로 판단된다.

This study demonstrates a variability in efficacy of mating disruption against the oriental fruit moth, Grapholita molesta, populations infesting apples cultivated in differential environmental conditions. Throughout the growing seasons, trap catches of G. molesta male moths and damaged leaf and fruit were examined to evaluate the efficacy of a commercialized mating disruptor. Treatment of the mating disruptor significantly reduced the trap catches of male moth in treated plot, compared to those of the untreated plot. This reduced trap catches were significantly correlated with leaf and fruit damage. Moreover, the highest host damage occurred in June just after the highest overwintering adult peaks in both plots. The treatment of mating disruptors in Chungsong effectively disrupted the overwintering population in April and May, resulting in no noticeable host damage during the following growing seasons. However, there was a marked difference in host damage between two plots, especially in late seasons. Variation in the efficacy of mating disruption technology in terms of host damage appeared to be related with nearby pheromone-untreated orchards, which may result in the immigration of gravid females.

Different timings of coverage by a small paper bag at the young fruit stage were tested in order to evaluate the effect on the protection of fruit damage occurred by disease or pest, and quality deterioration during organic cultivation of 'Hwasan' (Pyrus pyrifolia Nakai) pear cultivar. The occurrence of four major moth populations and two major diseases in pears were monitored from April to September 2015. Among major moths and diseases, Grapholita molesta and pear rust were found often in the organic pear orchard, and they were observed frequently in May. Coverage by a small paper bag at the young fruit stage resulted in better fruit quality and a higher proportion of commercial fruits compared to a coverage timing of conventional paper bag. Interestingly, the fastest coverage timing of a small paper bag at the young fruit stage (when it was covered in April) showed the lowest occurrence of damaged fruits, which indicates that it successfully protected fruits from the damage caused by moths and diseases during April and May. Moreover, this timing of small paper bag coverage did not negatively affect the major qualitative and quantitative characteristics of fruits. These results suggest that early coverage by a small paper bag at the young fruit stage can be considered an efficient management strategy for organic cultivation of ‘Hwasan’ pear cultivar.

In this study, the construction and maintenance procedures of the freeze damage mitigation method were proposed through analysis of current freeze damage status and related literature review. Considering the characteristics of the Gang-won area, it can be used for the construction guideline and maintenance manual of the freeze damage mitigation method to be developed.

Background : The use of the rain shelter facility gets more prevalent in the Ginseng cultivation area these days. This study is designed to establish a technique for the stable cultivation of Ginseng in the rain shelter facilities in high temperature (above 30 ℃) without the damage from high temperature Methods and Results : This study was carried out on 3-year Ginseng roots in 2016 in order to find out how to stably cultivate Ginseng in high temperature without suffering the high temperature damage during the cultivation of Ginseng under rain shelter facilities. The rain shading materials were coated with scattering film (scattering film + black shading net 90%), bluish white double-sided film (shading 85%) and PE film (PE film + black shading net 90%). The damage reduction by high temperature was made to the scattering film and bluish-white double-ended film only. An aluminum screen (shading rate: 40%) was installed when the high temperature (above 30℃) was reached while the isoprene (solution of 2000 times) was sprayed 4 times every 7 days from the full development stage. The light transmittance was 12.6 - 13.4% for the scattering film, 10.5 - 10.8% for the bluish-white double sided film and 7.1% for the PE film in the first coating while it was 7.3% for the scattering film and 7.1% for the bluish-white double-sided film when the aluminum screen was installed in high temperature. The high, average and low values in the relative humidity were higher inside the facility than in the outside during the survey period. The area of leaf was the largest under the scattering film. The area of leaf was the largest for the scattered film under the aluminum shade of 40% shading followed by that of spraying of isoprene 4 times, and that of the no-treatment. As for the growth under ground, the growth of underground shoots increased by 40% in aluminum screen, 53.7% in shading and 26.1% in the spraying of isoprene 4 times than non-shading while there was no difference among other rain shelter materials. Conclusion : The result of the research showed that when the scattering film is selected as the rain shelter material film for the cultivation of Ginseng, it is necessary to shade the sunlight as much as 40% by using the aluminum screen or the shading net to reduce the high temperature damage.

Background : Schisandra chinensis is being weighted difficulties in stable production, there is increasing drought damage caused by climate change as shallow rooted crops. Therefore, the study was performed for water supply capacity and growth characteristics analysis by setting the irrigation method for the drought damage reduction. Methods and Results : Test material was used sophomore V-shaped planting Schisandra chinensis. Irrigation method were surface watering, underground watering, sprinkler and untreated. Underground irrigation was irrigation that buried hose and then dug up the 15㎝. Soil moisture tension was the irrigation after fixed at -30 ㎪(23%). Irrigation timing was performed in June-July that high drought damage and made the most fruit enlargement. The main investigating items were investigated fruit growth, normal fault rate, soil moisture and EC content according to the irrigation method. Normal fruit rate according to irrigation method were appeared in sprinkler(81, 74 %)>underground irrigation(76, 69 %)>surface irrigation(76, 67%)>untreated(66, 52 %). Cluster length of yield component was determined to effective irrigation method in fruit growth the highest in sprinkler. Soil moisture contents was maintained at appropriate level with significant -30㎪(23 %) in the sprinkler. EC content low with a downward trend in underground irrigation and sprinkler. Water supply capacity according to Irrigation Method were sprinkler 40 tons, underground irrigation 85 tons, surface irrigation 138 tons. Conclusion : Appropriate watering methods for drought damage reduction of Schisandra chinensis caused by climate change was determined in the most efficient irrigation method in sprinkler that high fruit growth and normal fruit rate, lower the required of water supply capacity.

In the winter season, a many problems such as water leaks, icicles, etc. has occurred by freezing phenomenon at the road tunnels. Therefore, in order to reduce property damage caused by cold environment, it is necessary to establish a mechanism of freezing and thawing of tunnel structures. In this study aims to introduce the method for freeze damage reduction and suggest the plan for practical use of it.

최근 강우와 토지이용의 특성 변화로 인해 도시지역의 재해위험은 크게 악화되고 있다. 과거 도시지역 재난관리는 하천제방, 우수관망, 빗물펌프장 등과 같은 구조물적인 대책에 집중되었지만, 최근 도심지 침수피해의 증가는 추가적인 대책 마련이 시급함을 시사한다. 이에 국내외의 재난관리 정책에서는 장기적인 관점에서 사전예방 차원의 재해저감 및 완화단계에 초점을 둔 비구조적 대책들을 중요시하고 있다. 이에 본 연구에서는 기존의 구조물적 대책에 더하여 비구조물적 대책의 효과를 경제성 측면에서 살펴보고자 한다. 이를 위해 기존의 우수관망의 설계기준을 상향 조정하고, 가용한 비구조물적 대책들을 고려하여 유출모의를 수행하였다. 분석 결과를 전체적으로 보면, 우수유출저감시설, 불투수율 규제, 토지이용 관리 등과 같은 비구조물적 수방대책은 기상이변에 대응하기 위한 보완적 수단으로써 시가지유역의 막대한 침수피해를 최소화하고, 간접적으로는 도시 물순환 체계를 회복하는 측면에서 경제성을 확보할 수 있을 것으로 보인다.

전통적인 다기준의사결정(Multi-Criteria Decision Analysis, MCDA)기법은 복수 대안을 평가기준과 의사결정권자의 선호도에 따라 평가하여 유역 전반에 걸친 최적 대안을 선정하는 데 있어 효율적으로 사용되는 기법이다. 하지만, 홍수터 관리를 위한 유역 전반에 걸친 의사결정 정보는 지역적 특색을 반영할 수 있는 공간적 변동성을 체계적으로 파악할 수 있는 능력에 제한을 받고 있다. 이와 관련하여 최적대안 결정시 지리정보체계(GIS)의

최근 기후변화에 의한 이상기후에 따라 홍수, 가뭄, 산사태, 등 자연재해 현상들이 예고없이 빈번히 발생함에 따라 국가와 국민들에게 막대한 물질적·정신적 피해를 입히고 있다. 특히 집중호우의 증가와 인구밀집, 산업화로 인하여 도시지역의 피해는 더욱 심각해질 것으로 전망되고 있어 이를 개선하기 위한 기술적 대책이 필요하다. 따라서 본 연구에서는 기후변화로 인한 자연재해에 대비하기 위한 일환으로 미래 기후변화를 예측을 통해 도심지에 미치는 영향을 파악하고, 또한 이에 대응할 수 있는 대안을 설정함으로써 효율적으로 기후변화에 대응하기 방안을 제시하기 위함이다. 대상지역으로는 인천광역시 계양구 일대를 선정하였으며, CNCM3 기후모형과 A1B, A2, B1 세 가지 시나리오를 이용하여 기후변화의 영향으로 인해 발생할 수 있는 확률강우량을 산정하였다. 산정된 확률강우량을 이용하여 대상지역 도시 배수시스템의 홍수유출여부를 모의(XP-SWMM 이용) 후, 기후변화에 대응하기 위한 관거 용량 개선의 대안을 선정하고 경제성 분석을 실시하였다. 그 결과, 편익·비용비(B/C ratio)가 1을 초과하였으므로 기후변화의 영향을 고려한 관거의 용량 개선 대책(안)의 경제적 타당성을 확인할 수 있었다.

본 연구에서는 유한 요소법과 고도화된 손상 탐지 기법을 결합하여 구조적 손상을 규명하는 방법을 다룬다. 본 연구의 특징은 충격하중을 받는 구조물의 동적 거동 특성을 분석하여 이를 임의의 손상 형태를 갖는 판에 적용한다는 것이다. 이러한 방법은 손상된 부위의 강성 분포를 추정할 뿐만 아니라 손상의 정도도 파악할 수 있는 장점을 갖으며 분할 요소수의 제한을 두지 않는다. 제안된 방법을 검증하기 위하여 본 알고리즘은 임의의 손상을 갖는 박판에 대하여 적용하기 한다. 수치해석 결과로부터 제안된 알고리즘은 수치적 효율성과 함께 임의의 손상 분포를 규명할 수 있음을 보여준다.