• 한국생산제조학회지
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• 제25권6호
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• pp.462-470
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• 2016

The locking load of a conventional manhole depends on the weight of its cover. Locking-type manhole structures with a special locking mechanism were recently developed to prevent accidents such as stolen cover, away cover from a frame. The weight of the manhole structure can be reduced under structural safety because the locking force of a locking-type manhole is greater than the weight of the cover. A light-weight manhole cover is developed in this study by using a finite element stress analysis and the design of experiments. Static stress analysis and fracture experiments are also conducted to analyze the states of the initial product. The optimum light-weight manhole cover considering manufacturing molds is developed and tested. Consequently, the weight was found to reduce by 16%. In addition, the fracture load increased by 38%.

• 한국지반신소재학회논문집
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• 제2권3호
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• pp.11-18
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• 2003

최종복토의 설계에 있어 가장 중요한 요소 중 하나는 매립지 내부로 우수의 침투를 제한하는 것이다. 우수의 침투는 침출수 발생량을 증가시켜 침출수 처리 비용의 증가에 따른 매립지 운영 비용을 증가 초래한다. 따라서, 매립지의 최종복토층은 우수의 침투를 최소화하기 위해 단독의 다짐점토층 또는 HDPE와 다짐점토층의 복합으로 구성된 차단층을 포설하도록 되어 있다. 그러나 다짐점토층과 HDPE는 매립 폐기물의 분해에 의해 발생하는 침하에 의해 손상이나 파손이 발생할 우려가 있다. 따라서 본 연구는 매립 종료 후 침하에 따른 폐기물 매립지 최종복토층 HDPE의 영향에 대해 평가하고자 수행되었다. 현장시험시공과 lysimeter test, 최종복토 후 침하 예측 결과 최종복토층의 HDPE는 침하에 의한 영향을 크게 받지 않는 것으로 나타나 침하에 대해 안정하다고 할 수 있다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 춘계학술발표회 논문집
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• pp.397-408
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• 2003

The information about land use presents future development and vision being the basis of nation development; therefore, it is necessary to more active research that can detect wide land use and changes for the information and efficient management about land use. In this study, we wished to analyze effectively land use changes to Ansan city that is fast changing land use by the latest national land development and urbanization. this study executed land-cover classification using 4 year's Landsat TM images including Ansan city, and efficiently could manage the result of land-cover changes through Arc/Info GRID analysis. Especially, by using change detection system that is developed in this research, we could variously detect land-cover changes, and query and search easily past land-cover changes of pixels that correspond to specific region.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.446-449
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• 2002

Recently, advanced manufacturing system with high speed and intelligent have been developed for the betterment of machining ability. In this case, reliability prediction work with motion characteristic evaluation of sliding cover has also important roll from design procedure to manufacturing and assembly process. Accordingly in this study, H/W test -bed system for reliability evaluation of sliding cover has been developed to obtain proper reference data for design of new model, and also prevention trouble, quality and life cycle improvement extremely for advanced mother machinary.

• Journal of Ecology and Environment
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• 제41권2호
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• pp.34-44
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• 2017

Background: Monitoring terrestrial vegetation cover condition is important to evaluate its current condition and to identify potential vulnerabilities. Due to simplicity and low cost, point intercept method has been widely used in evaluating grassland surface and quantifying cover conditions. Field-based digital photography method is gaining popularity for the purpose of cover estimate, as it can reduce field time and enable additional analysis in the future. However, the caveats and uncertainty among field-based vegetation cover estimation methods is not well known, especially across a wide range of cover conditions. We compared cover estimates from point intercept and digital photography methods with varying sampling intensities (25, 49, and 100 points within an image), across 61 transects in typical steppe, forest steppe, and desert steppe in central Mongolia. We classified three photosynthetic groups of cover important to grassland ecosystem functioning: photosynthetic vegetation, non-photosynthetic vegetation, and bare soil. We also acquired normalized difference vegetation index from satellite image comparison with the field-based cover. Results: Photosynthetic vegetation estimates by point intercept method were correlated with normalized difference vegetation index, with improvement when non-photosynthetic vegetation was combined. For digital photography method, photosynthetic and non-photosynthetic vegetation estimates showed no correlation with normalized difference vegetation index, but combining of both showed moderate and significant correlation, which slightly increased with greater sampling intensity. Conclusions: Results imply that varying greenness is playing an important role in classification accuracy confusion. We suggest adopting measures to reduce observer bias and better distinguishing greenness levels in combination with multispectral indices to improve estimates on dry matter.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.153-158
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• 2000

This paper addresses an intelligent robot control system using an off-line programming to teach a precise assembly task of electronic components in a flexible way. The investigated task consists of three job: heat caulking test, soldering on a circuit board, and checking of soldering defects on the back cover of a camera. This study investigates the remodelling of the most complicated cell in terms of the accuracy and fault rate among the twelve cells in a camera back-cover assembly line. We have attempted to enhance back-cover assembly line. We have attempted to enhance soldering quality, to add task flexibility, to reduce failure rate, and to increase product reliability. This study modifies the cell structure, and improves the soldering condition. The developed all system implements the real-time control of assembly with vision data, and realized an easier task teaching on off-line programming.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.820-824
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• 2003

One of the most important research areas on remote sensing is spectral unmixing of hyper-spectral data. For spectral unmixing of hyper spectral data, accurate land cover information is necessary. But obtaining accurate land cover information is difficult process. Obtaining land cover information from high-resolution data may be a useful solution. In this study spectral signature of endmembers on ASTER acquired in October was calculated from land cover information on IKONOS acquired in September. Then the spectral signature of endmembers applied to ASTER images acquired on January and March. Then the result of spectral unmxing of them evauateted. The spectral signatures of endmembers could be applied to different seasonal images. When it applied to an ASTER image which have similar zenith angle to the image of the spectral signatures of endmembers, spectral unmixing result was reliable. Although test data has different zenith angle from the image of spectral signatures of endmembers, the spectral unmixing results of urban and vegetation were reliable.

• 한국의류학회지
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• 제22권6호
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• pp.737-748
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• 1998

This study was carried out on 132 obese women who satisfied both of conditions for obesity: equal to or over 1.6 in Rohrer index and 90 in bust girth. The purpose of the study was to set up a sizing system using the loss function which would be a guide for obese women to select ready-to-wear of suitable size. The results were as follows. 1) In the sizing system for large size apparel industry, each company has 4 to 7 sizes that differ in their content and number. Producing only 5 sizes was trying to minimize the producti on expenses. 2) The sizing system according to the loss function was the follwings. The height was 3: 149, 154.5 and 161 cm. The bust girth was 5:96.5, 100.5, 104, 107.5, 112 cm. The hip girth was 5: 95, 99, 102.5, 105.5, 110 cm. 3) In comparing the cover ratio of the newly suggested sizing system for obese women's garment with that of the Korea Sizing system for women's garment, the former was founded to have the greater cover ratio.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 봄 학술발표논문집 Vol.31 No.1 (A)
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• pp.628-630
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• 2004

Distributed Denial of Service(D-DoS) 공격을 차단하기 위해서는 AS(Autonomous System) 경계 라우터에 필터를 설치하는 것이 필요하다. 필터가 설치되는 라우터의 개수를 최소로 하는 Vertex Cover(VC)--모든 edge를 커버하는 Vertex의 모임--을 찾아내는 방법은 NP-complete 문제가 된다. 따라서 Vertex Cover(VC) 근사기법 중에서 Greedy 알고리즘과 Approximated VC 알고리즘에 대해 Vertex Cover(VC)을 찾아내는 방법을 적용하여 실험하였다. Vertex Cover(VC)를 찾을 경우 Worst case에서 이론상 VC수의 최대 2배의 Vertex Cover(VC)를 찾아낼 수 있는 Approximated VC 알고리즘의 장점과 적은 수의 Vertex Cover(VC)로 모든 edge를 커버할 수 있는 Greedy 알고리즘［7］의 장점을 모두 갖춘 Vertex Cover(VC) 근사 기법을 구현하였다. NS-2를 이용한 실험 결과, 제안된 알고리즘은 Greedy 알고리즘보다 Vertex Cover를 찾아가는 단계 수에 따른 커버되는 층 노드 수를 비교하였을 때. 전체 노드의 75%를 커버하는데 24번의 단계가 필요하여 Greedy 알고리즘의 40개 보다 40%의 단계의 수적인 감소가 일어났으며 전체노드의 90%를 커버하는데 38%의 단계 개수의 감소가 일어났다. 실험으로 제안된 알고리즘이 Vertex Cover(VC) 톨 찾아가는 단계 측면에서 좀더 빠르게 AS 경계 라우터에 필터를 설치하여 D-DoS에 효율적으로 대처해 나갈 수 있음을 확인할 수 있다.

• 한국토양비료학회지
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• 제49권5호
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• pp.531-540
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• 2016

The adoption of legume cover crops in no-tillage system can contribute to improve soil fertility by providing several benefits, including reduction in soil erosion, suppression of weed growth and N supply to subsequent crops. We conducted a field study to investigate the effect of cover crops and nitrogen fertilization rates on yield and nitrogen use efficiency of waxy corn (Zea mays L.) in no-tillage upland field. Two legume cover crops, hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnuturn L.) were mechanically terminated with roller in early June. For each cover crop treatment, nitrogen (N) fertilizer was applied at three different rates (145, 72.5 and $0kg\;N\;ha^{-1}$). The growth and yield characteristics of corn were significantly affected by the N fertilization rates in crimson clover plots, which suggest N mineralization from the cover crop residue was not sufficient. In contrast, N fertilization rates had no significant effect on growth and yield of corn in hairy vetch plots, indicating that the amount of N released from the cover crop is large enough to meet most of the N requirement of corn. However, the application of N fertilizer in hairy vetch cover plots resulted in slight increase of crop yield, though not statically significant, and high levels of N concentration in corn plant tissue possibly due to luxury consumption of N. Organic residues on the soil surface in hairy vetch cover plots had substantial amounts of N after harvest, ranging from 100 to $116kg\;N\;ha^{-1}$, which is presumably retained during winter season and released by microbial mineralization in subsequent year. The highest nitrogen yield efficiency was achieved in the plot with hairy vetch cover and no N fertilizer application, followed by the plot with hairy vetch cover and $72.5kg\;N\;ha^{-1}$ fertilization rate. In conclusion, hairy vetch showed better performance in corn productivity as compared with crimson clover. In addition, it was concluded that the application of N fertilizer between 0 and $72.5kg\;N\;ha^{-1}$ in combination with hairy vetch cover crop might be most efficient for corn yield under no-tillage system with climatic and soil characteristics similar to those of the experimental site.