• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.3A
• /
• pp.265-275
• /
• 2010

Concrete filled steel tube and concrete encased steel tube columns are expected to have confined effects of concrete by steel and reinforced effects of local buckling by concrete. On the basis of confined state concrete models of previous researches, stress-strain and load-displacement relations of RC, CFT and CET columns are analyzed by steel ratio. After comparing analysis results with experimental results, Modified stress-strain relations are derived through evaluation the influence upon confined effects of concrete in each cases. Also, the modified stress-strain models are carried out to be compared with specified strength of various countries.

• Journal of Korean Society for Geospatial Information Science
• /
• v.22 no.4
• /
• pp.53-61
• /
• 2014

Landsat OLI satellite imagery can be applied to various remote sensing applications, such as generation of land cover map, urban area analysis, extraction of vegetation index and change detection, because it includes various multispectral bands. In addition, land cover map is an important information to monitor and analyze land cover using GIS. In this paper, land cover map is generated by using Landsat OLI and existing land cover map. First, training dataset is obtained using correlation between existing land cover map and unsupervised classification result by K-means, automatically. And then, spectral signatures corresponding to each class are determined based on training data. Finally, abundance map and land cover map are generated by using iterative spectral mixture model. The experiment is accomplished by Landsat OLI of Cheongju area. It shows that result by our method can produce land cover map without manual training dataset, compared to existing land cover map and result by supervised classification result by SVM, quantitatively and visually.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.32 no.5
• /
• pp.443-450
• /
• 2014

To fulfill the recent increasement in the public and private demands for various spatial data, the central and local governments started to produce those data. The low-level land cover map has been produced since 2000, yet the production of high-level land covered map has started later in 2010, and recently, a few regions was completed recently. Although many studies have been carried to improve the quality of land that covered in the map, most of them have been focused on the low-level and mid-level classifications. For that reason, the study for high-level classification is still insufficient. Therefore, in this study, we suggested the automatic extraction of land readjustment for paddy land that updated in the mid-level land mapping. At the study, the RapidEye satellite images, which consider efficient to apply in the agricultural field, were used, and the high pass filtering emphasized the outline of paddy field. Also, the binary images of the paddy outlines were generated from the Otsu thresholding. The boundary information of paddy field was extracted from the image-to-map registrations and masking of paddy land cover. Lastly, the snapped edges were linked, as well as the linear features of paddy outlines were extracted by the regional Hough line extraction. The start and end points that were close to each other were linked to complete the paddy field outlines. In fact, the boundary of readjusted paddy fields was able to be extracted efficiently. We could conclude in that this study contributed to the automatic production of a high-level land cover map for paddy fields.

• Journal of Sericultural and Entomological Science
• /
• v.24 no.1
• /
• pp.19-24
• /
• 1982

This experiment was carried out to develope a new planting system from the economical point of view, using the various sizes of mulberry saplings ranged from 3mm to 7mm (3, 4, 5 and 7mm) in diameter of branches. They were planted densely (2,285 trees/10a) in vinyl film-and non-mulching system. The results are summarized as follows. 1. There are no differences in growth and yield of the planting year between 6mm and 7mm saplings. 2. The vinyl mulching affords an abundant growth of the saplings due to retaining of soil temperature and moisture. The dense planting with vinyl film mulching gave rise to 26% and 7% increase of leaf yield, using the saplings sized of 7mm and 5mm, respectively. 3. On the other hand, it was evident that the use of 6mm saplings in non-mulching and 5mm ones in mulching redused possibly the sapling cost. It was also noteworthy an additional profit took places in the yield increase, the cost reduction of saplings and weeding by using the 7mm and 5mm saplings in mulching system. It amounted to the increase of ￦33,800 and ￦24,520, respectively over the use of 7mm saplings in non-mulching system.

• Journal of Navigation and Port Research
• /
• v.39 no.4
• /
• pp.335-344
• /
• 2015

This study aims to assess the effectiveness of zeolite, montmorillonite, and steel slag as capping materials to block the release of heavy metals from marine sediment depending on their depths. The results showed that all capping materials used this study were not effective in interrupting release of As. Zeolite had negative effect on the block of Cr release but it was significantly reduced to 5 cm by montmorillonite capping. In contrast to As and Cr, Cd, Ni, and Pb were not released even from uncapped sediments. Cu and Zn were the heavy metals those were most significantly influenced by the capping conditions. Cu release from marine sediments were effectively blocked by more than 1 cm depth of montmorillonite and more than 3 cm depth of zeolite. All capping materials were found to be effective in interrupting release of Zn from marine sediments. It was concluded that the zeolite, montmorillonite, and steel slag could be used as a potential capping material for interrupting the release of Cr, Cu, and Zn from the contaminated marine sediments.

• Weed & Turfgrass Science
• /
• v.1 no.4
• /
• pp.24-30
• /
• 2012

This study was conducted to select the cover crops in organic apple orchard by estimating the coverage of each cover crops and time-periodic weed occurrence. Seeding of Festuca myuros and Trifolium repens showed high contents of soil organic matter and phosphorus as compared with control. Seeding of Trifolium sp., Hordeum vulgare and Secale cereal reduced relatively occurrence of weed in May and S. cereal among others showed the greatest effect in June. In July, seeding F. arundinaceae and Poa pratensis showed low coverage and a lot of weeds occurred in their field. Fifty one species were occurred as weeds and it needs to removal of high and broadleaf weeds such as Chenopodium ficifolium, C. album var. centrorubru and Humulus japonicus in spring to increase the rate of ground cover. P. pratensis having the lowest cover rate showed the similar dry weight of weeds as compared with control. Trifolium sp. and Persicaria hydropiper had a high correlation with contents of soil organic matter and C. album var. centrorubru had a correlation with contents of soil phosphorus by CCA analysis.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2003.07a
• /
• pp.199-204
• /
• 2003

본 연구는 축산농장을 출입하는 차량을 소독하여 가축전염병 발생을 예방하기 위하여 수행 되었으며 그 결과를 요약하면 다음과 같다. 가 축사진출입 차량소독기는 차량의 폭에 따라 약액살포 붐대가 이동하여 일정한 간격에서 약액을 살포하도록 제작하였다. 나. 붐대의 각도를 차량출입 반대방향으로 0$^{\circ}$, 15$^{\circ}$, 30$^{\circ}$로 살포각도가 변화하였을 때 살포 각이 커질수록 후면에 약액이 고르게 피복되었다. 다. 살포압력 10kg/$\textrm{cm}^2$, 20kg/$\textrm{cm}^2$ 이었을 때 약액피복면적비가 75%-95%로 차량 전체에 고르게 피복 되었다. 라. 본 시작기의 소독소요시간은 차량 한대당 0.0042시간으로 관행 0.0083시간에 비하여 50% 감소하였고 소요비용도 455원으로 관행의 1,099원에 비하여 59% 절감효과가 있는 것으로 나타났다.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05c
• /
• pp.259-264
• /
• 1996

상용 Zircaloy-4보다 성능이 우수한 고연소도용 Zr 신합금을 개발하는 것을 목표로 외국에서 개발중인 12종의 신합금 피복관에 대한 특성평가, 부식기구 규명 연구, 국내에서 제조된 Zr 신합금의 특성평가를 실시하였다. 외국 피복관의 부식특성 평가로 부터 Sn을 0.6-1.0 wt.% 첨가하고 Nb을 0.4 wt.% 첨가하는 것이 내식성 관점에서 바람직함을 알 수 있었다. 여러 가지 LiOH용액에서의 부식기구 연구를 통해 수소화물이 부식가속의 원인임을 알 수 있었으며 수소화물 형성을 억제하는데는 Nb첨가가 효과적인 것으로 나타났다. 이와 같은 연구결과를 토대로 신합금의 개발방안을 수립하였으며 예비적으로 합금을 설계. 제조하여 특성시험을 실시한 결과, Zr-Sn-Nb-FeCr 합금이 우수한 내식성을 보이며 Fe, Mo는 강도 증가 효과가 큰 것으로 나타났다. 이러한 연구결과를 종합적으로 평가하여 신합금을 설계하고 노외성능 평가를 통해서 신합금을 선정한후, 단계적으로 하나로를 이용한 노내성능 평가를 실시할 예정이다.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05b
• /
• pp.52-57
• /
• 1997

국제 열 핵융합로 (International Thermonuclear Experimental Reactor) 의 중앙 솔레노이드(solenoid) 초전도 전자석의 피복관 (conduit) 으로서 가장 유력한 후보 재료인 니켈-철 기저 초합금에 대한 개선된 파괴역학적 거동 예측 모형을 개발하기 위하여 피로균열 성장과 파괴 인성 치의 측정이 사용되었다. 유한 요소법을 사용하는 상용 구조해석 코드인 ANSYS 제 5.2판에 의해 초전도 전자석 피복관 재료에 대한 탄소성 파괴역학적 거동을 살펴보았다. 정확한 파괴 기준을 개발하기 위하여 삼차원 J 적분 인자에 의한 결과를 사용하였다. 얇은 피복관재의 경우에 절대온도 4도에서의 적합한 파괴 인성치는 실제 단면효과를 고려한 표면균열 인장시험 결과를 토대로 J 적분으로 도출한 150 MPaㆍm$^{1}$2/ 로 제시되었다.

• Korean Journal of Remote Sensing
• /
• v.33 no.6_2
• /
• pp.1075-1087
• /
• 2017

In this study, we tried to utilize results of the change detection analysis for satellite images as the basis for updating the land cover map. The Sequential Spectral Change Vector Analysis ($S^2CVA$) was applied to multi-temporal multispectral satellite imagery in order to extract changed areas, efficiently. Especially, we minimized the false alarm rate of unsupervised change detection due to the seasonal variation using the direction information in $S^2CVA$. The binary image, which is the result of unsupervised change detection, was integrated with the existing land cover map using the zonal statistics. And then, object-based analysis was performed to determine the changed area. In the experiment using PlanetScope data and the land cover map of the Ministry of Environment, the change areas within the existing land cover map could be detected efficiently.