The New Vacuum Solar Telescope (NVST) is the largest solar telescope in China. When using CCDs for imaging, equal-thickness fringes caused by thin-film interference can occur. Such fringes reduce the quality of NVST data but cannot be removed using standard flat fielding. In this paper, a correction method based on multi-scale decomposition and adaptive partitioning is proposed. The original image is decomposed into several sub-scales by multi-scale decomposition. The region containing fringes is found and divided by an adaptive partitioning method. The interference fringes are then filtered by a frequency-domain Gaussian filter on every partitioned image. Our analysis shows that this method can effectively remove the interference fringes from a solar image while preserving useful information.

대규모 유한요소 모델을 빠르게 해석하기는 위해서 병렬 희소 솔버를 필수적으로 적용해야 한다. 이논문에서는 미세하게 변화하는 시스템 행렬을 대상으로 연속적으로 해를 구해야 하는 문제에서 효율적으로 적용가능한 반복-직접 희소 솔버 조합 기법을 소개한다. 반복-직접 희소 솔버 조합 기법은 병렬 희소 솔버 패키지인 PARDISO에 제안 및 구현된 기법으로 새롭게 행렬값이 갱신된 선형 시스템의 해를 구할 때 이전 선형 시스템에 적용된 직접 희소 솔버의 행렬 분해(factorization) 결과를 Krylov 반복 희소 솔버의 preconditioner로 활용하는 방법을 의미한다. PARDISO에서는 미리 설정된 반복 회수까지 해가 수렴하지 않으면 직접 희소 솔버로 해를 구하며, 이후 이어지는 갱신된 선형 시스템의 해를 구할 때는 최종적으로 사용 된 직법 희소 솔버의 행렬 분해 결과를 preconditioner로 사용한다. 이 연구에서는 첫 번째 Krylov 반복 단계에서 소요되는 시간을 동적으로 계산하여 최대 반복 회수를 설정하는 기법을 제안하였으며, 주파수 영역 해석에 적용하여 그 효과를 검증 하였다.

본 연구에서는 적층된 중앙개구부를 갖는 CNTFPC 복합재 판에 대하여 기하학적 비선형 동적 해석을 수행하였다. Hewitt and Malherbe 멀티스케일 모델을 기반으로 MWCNT의 함유 비율과 중앙개구부의 크기 변화에 따른 영향을 분석하였다. 1차전단변형 판이론에 근거하여, Newmark 방법과 Newton-Raphson 반복기법이 비선형 동적해석을 위하여 적용되었다. 본 연구에서 제안한 방법은 기존 문헌으로부터 도출 결과와 비교 검증하였다. 수치해석 예제는 MWCNT의 적절한 함유량 및 적층된 CNTFPC 구조의 구조성능의 향상시킬 수 있는 상호 관계를 상세 규명하였다.

솔껍질깍지벌레는 남부지방의 곰솔을 가해하는 주요 해충으로 최근 그 분포범위가 확산되고 있다. 현재 솔껍질깍지 벌레의 모니터링은 난낭의 조사를 통해 이뤄지고 있으나, 이는 매우 많은 인력이 필요하며 부정확하다. 따라서 페로몬을 이용한 솔껍질깍지벌레의 모니터링이 새로운 대안으로 제시되고 있다. 하지만 이 역시 적절한 가이드라인이 없어 현장적용에 큰 어려움이 있다. 본 연구 에서는 페로몬을 이용한 솔껍질깍지벌레의 효율적인 모니터링 기법 개발을 위하여 최적 페로몬 방출농도 및 트랩설치 방법을 규명하였으며, 페로몬의 새로운 합성기법의 개발 통하여 경제적 효율성을 기하였다. 성 페로몬에 대한 수컷 솔껍질깍지벌레의 유인효과는 100 μg부터 1,600 μg 까지의 처리에서 용량의존적인 관계를 나타내었으며 이 이상으로 처리할 경우 페로몬 처리 증가에 따른 유인개체수가 증가하지 않았다. 트랩의 설치 높이를 지표면으로부터 50cm, 100cm 150 cm로 구분하여 조사한 결과 지상부로부터 50cm에 설치한 트랩에 가장 많은 개체가 포획되었다. 새로운 방법으로 합성한 페로몬 역시 기존 페로몬과 마찬가지로 페로몬 처리량과 유인 개체수 간 용량의존적인 관계가 나타났다.

The black pine bast scale are the main insects of the Japanese black pine forest in Korea, and the distribution is spreading around the Japanese black pine forest in the east and west coast. However, after the nationwide survey in 2010, there has been no investigation on the distribution and spread of these, so we conducted the 2017 and 2018 surveys to determine the extent of the northern area inland or east and west. In the 2017 survey, outbreaks were observed in 35 areas from 47 dong or myeon of 14 cities or counties, mainly in areas not previously located in the outbreak area. In the 2018 survey, additional outbreaks were confirmed at 14 out of 23 areas in the East Coast region, and damage was detected at 27 out of 28 points in the inland area of the South Sea and distribution was found at 16 out of 17 in the west coast.

This study was performed to assess particulate matter removal efficiency of domestic air cleaner products in a field condition. The assessment also included air cleaners with different air removal mechanisms. The particulate matter (PM2.5) removal test with a different air removal mechanism using air cleaners showed that the electrostatic precipitation technique showed better performance compared with HEPA filters and other types of systems. Its removal efficiency was almost 95% in one of our operation times in the given test condition. It was assumed that not only the type of removal system but also the individual design, supply and exhaust system, and the automatically controlled air volume are involved in the removal efficiency. With respect to the area of application, tests with air cleaners for 40 m2, 60 m2, and 80 m2 areas revealed that particulate matter removal efficiency increased with the air cleaner that had a broad area of application. However, particulate matter removal efficiency by air cleaners did not correspondingly increase with the increase of the area of application. Moreover, the installation location did not influence particulate matter removal efficiency. Our results are expected to be used as the basic information for indoor air quality improvement and prediction using air cleaners.

A pilot-scale biocover was installed at a sanitary landfill for municipal waste, and the removal of volatile organic compounds (VOCs) by the biocover was evaluated for a long period of 550 days. The biocover (2.5 m W × 5 m L × 1 m H) was constructed with the mixture of soil, perlite, earthworm cast and compost (6:2:1:1, v/v). The total VOCs concentration of the inlet gas into the biocover was 820.3 ppb~7,217.9 ppb, and the total VOCs concentration of the outlet gas from the surface of the biocover was 12.6 ppb~1,270.1 ppb. The average removal efficiency of total VOCs was 87.6 ± 11.0% (60.5% for minimum and 98.5% for maximum). Toluene concentration was the highest among the inlet VOCs, followed by ethylbenzene, m, p-xylene and o-xylene. These aromatic VOCs accounted for more than 50% of the total VOCs concentration. Other than these aromatic VOCs, hexane, cyclohexane, heptane, benzene, and acetone were major VOCs among the inlet VOCs. Compared with the VOC profiles in the inlet gas, the relative contribution of dichloromethane to the outlet VOCs emitted from the biocover layer increased from 0.1% to 15.3%. The average removal efficiencies of BTEX in the biocover were over 84% during the operation period of 550 days. The average removal efficiencies of hexane, cyclohexane and heptane in the biocover were 86.0 ± 18.9%, 85.4 ± 20.4% and 97.1 ± 4.0%, respectively. The removal efficiency of VOCs in the biocover decreased not only when the ambient temperature had fallen below 5oC, but also when the ambient temperature had risen above 23oC. Information on the VOCs removal characteristics of the biocover installed in the landfill field can be useful for commercializing the biocover technology for the treatment of VOCs.

Boundary element solution method is introduced for radiation heat transfer problem with objects inside a 2-D enclosure, where shadow zone exists. Surfaces are assumed as diffuse gray in a transparent medium. Boundary integral and boundary element equations were derived from radiation transfer equation, and their theory is reviewed. Also the process of solution methods to implement the boundary element method is analysed and explained with consideration of shadow effects. BEM solution results are compared with two test problems and are found to be good agreements with the both analytic and ANSYS Fluent numerical solutions. Therefore the current BEM analysis for radiation heat transfer problem can be considered as verified, and their efficacy with engineering applicability is established as a result.

As a part of the research on existing structures of private homes from Joseon Era. Focusing on one hundred twenty five-purlin houses, the current study investigated the features and characteristics of the house structure from style, size, proportion and roof pitch, and measurements of key parts, and developed the following conclusions. Most are single-houses (89, 83%), and among them, there are 47 single front-terrace houses (39%), which is the highest number. The sizes of lower house structure do not differ greatly depending on the vertical structure, and single rear terrace house and double-house have relatively larger side sizes. The size of upper structure is larger in double-houses compared to other vertical structures, indicating a relatively higher roof. The cross-section measurement of major parts show that double-houses are larger than single-houses by 3cm in pillar, 3-4.5cm in crossbeam length, and 4.5cm in crossbeam width. However, Janghyeo width was consistent at 7.5 to 10.5cm, maintaining uniformity regardless of vertical structure of the houses. In addition, the cross-section measurements decreased from sixteenth to nineteenth century, with the size of pillar size decreasing the most. The result that the Janghyeo width is not related to the house structure house confirmed that the Janghyeo width was kept consistent regardless of the size of the house structure.

This study was conducted in order to improve opening efficiency of the miniaturized small-scale net for anchovy boat seine gear to reduce the fleet size. Field experiment was performed to observe geometry of nets by catcher boats. When the distance between the two ships was 150, 300 and 450 m and the speed of towing nets was 0.6, 0.9, and 1.2 kt, the vertical opening and actual opening of each part of the miniaturized small-scale net was as follows: the front part of the wing net, 6.8-9.5 m, 45-63%; the middle part of the wing net, 16.1-30.7 m, 34-65%; the entrance of the inside wing net, 21.6-41.2 m, 44-84%; the square and bosom, 17.4-34.0 m, 38-75%; the entrance of the body net, 16.5-29.4 m, 36-64%; the entrance of the bag net, 14.5-21.9 m, 70-106%; the flapper, 6.7-7.7 m, 81-83%, and the end of the bag net, 8.6-10.9 m, 64-81%. The tension of towing nets was measured to be 2,734-6,812 kg approximately, which indicates that the fleet can tow nets with 350 hp, the standard engine horse power. The fishing operation time was shortened comparing to existent net with the large-scale buoy attachment operation. It was also possible to operate the ship without fish detecting boat.

Existing reinforced concrete frame buildings designed for only gravity loads have been seismically vulnerable due to their inadequate column detailing. The seismic vulnerabilities can be mitigated by the application of a column retrofit technique, which combines high-strength near surface mounted bars with a fiber reinforced polymer wrapping system. This study presents the full-scale shaker testing of a non-ductile frame structure retrofitted using the combined retrofit system. The full-scale dynamic testing was performed to measure realistic dynamic responses and to investigate the effectiveness of the retrofit system through the comparison of the measured responses between as-built and retrofitted test frames. Experimental results demonstrated that the retrofit system reduced the dynamic responses without any significant damage on the columns because it improved flexural, shear and lap-splice resisting capacities. In addition, the retrofit system contributed to changing a damage mechanism from a soft-story mechanism (column-sidesway mechanism) to a mixed-damage mechanism, which was commonly found in reinforced concrete buildings with strong-column weak-beam system.

Crawling robots are advantageous in overcoming obstacles. These robots have characteristics such as light weight and outstanding mobility. In case of large robots, they have difficulties passing narrow gaps or entering the cave. In this paper, we propose a milli-scale hexapedal robot using 4-bar linkages. Two conditions are necessary to enable efficient walking. In short, the trajectory of the foot must be elliptical, and the lowest point of the foot should be the same. These conditions are satisfied with a novel leg design. The robot has a pair of three legs and the legs are coupled to operate simultaneously. Each set of the legs are installed to robot’s both sides and the legs satisfy the equal lowest foot point and elliptical trajectory. As a result, this hexapedal robot can crawl with 0.56m/s speed.