• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.354-360
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• 2022

The aluminum handrails used for promoting structural strength and weight reduction of the topside in an offshore platform are designed according to international standards (ISO, NORSOK, and Austria Standard), and consider the most conservative load combinations. Existing aluminum handrails are bolted to a socket when installed on the topside of a platform, and the amount of deflection of the handrail is largely influenced by the socket design. However, the importance of socket design has been overlooked, and furthermore, separate evaluation procedures or guidance for socket design are ambiguous. Therefore, a series analysis was performed for estimating the structural strength of aluminum handrails to obtain the governing parameters that minimize their deflection against loads. Experimental verification was performed to validate the structural safety of the new model, and we confirmed that all were satisfied within allowable deflection according to international standards. The developed model could be used in several areas in the future as it is lighter and more productive compared to existing models from overseas makers.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2436-2438
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• 2002

전자제품의 소형화 및 고기능화 추세에 따라 부품의 크기가 작아지고, PCB 회로의 고집적화가 이루어지면서 생산 장비의 고속성, 정밀성 등의 필요성이 대두되고 있다. 소형 부품 조립에 있어 대표적인 SMD 장착 장비인 칩마운터의 경우 시스템의 고속성 정밀성을 향상시키기 위해서 부품검사를 담당하는 고속의 영상 처리 알고리즘이 필수적이나 개발업체간의 특수성으로 인해 공개적으로 논의되고 있지 않다. 따라서 본 연구에서는 실제 칩마운터에 적용되는 사양을 기준으로 영상처리를 이용한 부품 외형 검사를 통해 위치 및 각도 오차를 계산하는 알고리즘을 제안하였으며, 제시된 알고리즘의 신뢰성 및 유효성을 확인하기 위한 부품 검사 실험을 수행하였다. 아울러, 본 논문에서는 부품검사방법의 정밀도를 높이기 위하여 부화소(subpixel)를 고려한 검사방법을 적용하였다.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.200-204
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• 1998

Physical and chemical properties of artificial soil produced by firing process were analyzed and compared with normal dry field soil and soil quality standards. Material used for production was water and wastewater treatment sludge, chabizite, and lime. The mixed material was thermally treated in the firing kiln at about $300^{\circ}C$ and $1,000^{\circ}C$, respectively, as per designed process. General properties of the artificial soil were classified as sand by unified soil classification method and similar to the dry-field soil, and even soil conditioning effect were expected when it is mixed properly with normal soil. The artificial soil is high in pH and permeability compared to the dry-field soil. Heavy metal concentrations of the artificial soil met the soil quality standards for the farmland. Overall, the artificial soil was thought to be an appropriate soil which can be returned safely to the nature without significant adverse effect. The cost for the artificial soil production process needs to be lowered for practical application as a sludge treatment, therefore, commercializing of the artificial soil is under review.

• Journal of Korea Water Resources Association
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• v.40 no.3
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• pp.205-214
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• 2007

The objective of this study is to generate the regional scale runoff scenarios by using IPCC SRES A2 climate change scenario for analyzing the spatial variation of water resources in Korea. The PRMS model was adopted to simulate long-term stream discharge. To estimate the PRMS model parameters on each sub-basin, the streamflow data at 6 dam sites and Rosenbrock's scheme are used for model parameter calibration and those parameters are translated to ungauged catchments by regionalization method. The other 3 dam sites are selected for the verification of the adequateness of regionalized model parameters in ungagued catchments. The statistical results show that the simulated flows by using regionalized parameters well agree with observed ones. The generated runoff scenarios by climate change are compared with observed data on 4 dam sites for the reference period. The consequences show that the selection of climate station for generating climate scenario affects the reliability of climate scenario at sub-basin. The comparison results of the stream flows between the 30-year baseline period (1971-2000) and future 90-year (2001-2030, 2031-2060, 2061-2090) show that the long-term mean annual runoff in the Han River has increasing trend, while the Nakdong, the Gum, the Youngsan and the Sumjin Rivers have decreasing trend.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.2
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• pp.73-79
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• 2020

This study was conducted to develop a technique for the stable production of Italian ryegrass(IRG) seeds in reclamation sites. Harvesting 35 days after heading in Autumn resulted in the highest production, an average of 2,232kg/ha. The production yield decreased due to seed loss as harvesting was delayed to 45 and 55 days post-heading. For the harvested 35 days post-heading, under growing rice sowing resulted in 80% seed yield of after rice sowing's; spring sowing resulted in 40%. After rice sowing using the domestic IRG seeds of 30kg/ha produced the highest seed yield of 2,507kg/ha. The highest straw yield has resulted when using the imported IRG seeds of 20kg/ha for after rice sowing 35 days post-heading fresh weight 36,667kg/ha, dry weight 14,500kg/ha, and TDN weight 7,895kg/ha.

• Journal of Animal Environmental Science
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• v.18 no.2
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• pp.111-122
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• 2012

Establishment of the LFQC (Liquid Fertilizer Quality Certification) system is very urgent issue for recycling livestock manure as renewable resources in Korea faced with environmental problem of manure application to land due to intensive livestock farming. In this study, we investigated relevant laws and regulations on livestock manure fertilizer, certifications of eco-friendly agricultural products, government policies on livestock manure management to establish reasonable direction of Korean LFQC (Liquid Fertilizer Quality Certification) system. As a result from this study, the liquid fertilizers in 'LFQC' system could be classified as three levels according to the usage patterns in field; 1st. Individual Farm Level (IFL), 2nd. Joint Farm Level (JFL), and 3rd. Commercial Level (CML). And finally, we found some characteristics in 'Main Level-Grading Factors' of liquid fertilizer such as fertilizing value, harmfulness, stability, uniformity, economic effect, storage potential, commercial value, functionality. Those items were considered to be the key factors for the establishment of 'LFQC' system. More research on 'Evaluation Standards' for concrete guideline and on the 'Main Level-Grading Factors' be needed to complete Korean LFQC system.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.198-202
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• 2009

기후변화는 강수와 기온을 변화시켜 수자원에 지대한 영향을 미칠 것으로 알려져 있다. 따라서 이에 대한 안정적인 수자원 관리를 위해서는 기후변화 영향을 정량적으로 평가하는 것이 필요하다. 기본적으로 기후변화에 대한 수자원의 영향을 연구할 때 '온실가스 배출시나리오, GCMs을 통한 기후모의, 시공간적 편차보정을 위한 상세화, 유출모형 적용을 통한 유출시나리오 생산'의 과정을 거친다. 그러나 유출시나리오를 얻기까지 과정에는 각각 불확실성을 가지고 있기 때문에 최종결과의 불확실성은 각 과정을 거치면서 매우 커진다고 할 수 있다. 다양한 배출시나리오, GCM 결과, 유출모형에 대해 단순평균 혹은 가중치를 주는 multi-model ensemble 기법은 각 경우에 따른 값의 범위를 제시할 수있다는 점 때문에 불확실성 평가에서 주로 이용되고 있다. 본 연구에서는 우리나라 5대강 유역 109개 중권역에 대해 multi-model ensemble을 적용하여 기후변화에 의한 수자원 영향을 평가하였다. 1971년에서 2100년까지 120년 기간에 대해 3개의 온실가스 배출시나리오, 13개의 GCMs 결과들을 수집하여 총 39개의 기후시나리오를 이용하였고, 이를 8개의 유출모형에 적용하여 총 312개의 유출시나리오를 생산하였다. 생산된 유출시나리오를 기준시간(1971${\sim}$2000)에 대한 미래의 세 기간(2020s, 2050s, 2080s)으로 나누어 변화율을 분석한 결과 여름철 유출량과 겨울철 유출량이 증가될것으로 나타났으나 겨울철 유출량 전망은 여름철에 비해 불확실성이 큰 것으로 나타났다. 공간적으로는 한강유역이 위치한 북쪽유역이 남쪽에 비해 불확실성이 큰 것으로 나타났다. 결과적으로 유출의 시공간적 편차에 의해 우리나라 수자원은 홍수피해 증가가 예상되었으며, 월별유출량의 변화로 인해 용수확보와 관리에 어려움이 증가할 것으로 전망되었다.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.539-547
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• 2019

Recently, the international community signed a climate change agreement to prevent global warming. Yet currently, the fossil fuels have been widely used in to supply building energy for cooling and heating. The Green Building certification (G-SEED), an energy efficiency rating for new or existing buildings requires that buildings meet certain conditions. Insulation is used as a building material to reduce the energy supply to buildings and to improve the thermal insulation, and it accounts for more than 90% of the total heat resistance provided by the building surface components that meet the energy-saving design standards of new buildings. In this investigation, a performance evaluation study was conducted through an experimental study by directly extracting the foam polystyrene insulation on-site during the remodeling of a building that was in the range of 22~38 years old. Through tests, it was found that the thermal conductivity of the extrusion method insulation (XPS) was reduced by 48% and the compressive strength of XPS decreased by 36% compared to KS M 3808, which is the initial quality standard. For bead method insulation (EPS) with a thickness of 50mm, the thermal conductivity, the compressive strength, and flexural failure load were similar to the initial quality standard. Therefore, in the calculation of the primary energy requirement per unit area per year, the performance of bead method insulation can be estimated simply by considering the thickness of the insulation, while a correction factor that considers its performance deterioration should be applied when extrusion method insulation is used.

• Korean Journal of Construction Engineering and Management
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• v.13 no.5
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• pp.103-112
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• 2012

Republic of Korea is recently becoming an advanced country with increasing standard of living. This is causing a lack of employment in the construction industry because of high labor costs and it is resulting rapid increase in foreign labors. Modular Method of Construction can be defined as 50%~90% of the entire process is completed in factory, and transferred to construction field to install. The main purpose of this process is to minimize the entire process that possibly can be done at construction field in order to maximize the quality. The current local usage of Modular Method of Construction started at Shin Ki Elementary School during 2003 and it is widely used for military facilities. It should be used more because it has strengths of spending short time period to complete and low production costs. It can make a change if Modular Method of Construction is applied. Toyota is currently producing vehicle with conveyor system and if Modular Method of Construction is applied, then it is possible to reduce the waste of labor, and automatic production time. Expansion of the modular Market can be expected by applying this method because it will improve producing costs, high quality, and enforced process. This research tried to solve the problem of factory's manufacturing production by applying local Modular Method of Construction to provide suggestions and analyze the profitability with applied conveyor system. It is depending on produced model, but this research's model will take 20 months including assessment of payback period.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.74-84
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• 2009

The study aims that high quality recycled sand by wet manufacturing system can be used in practical way through basic material property. The basic material property test was done by 4 categories, dry manufacturing system (1) tandem and (2) parallel, wet manufacturing system (3) large capacity and (4) small capacity. RS-IV is the final production of (1) to (4) method, it is tested via KS F 2573 (recycled fine aggregate). RS-IV is satisfied with 4 items, those are absolute dry density, 0.08mm sieve throughput, clay lump amount, and organic impurity substance content. However, absorptivity item has problem in (1) and (2) method, (3) and (4) method are confirmed with norms 5% low. Also, the production quality of wet manufacturing system is better than dry manufacturing system in absolute dry density, absorptivity, 0.08mm sieve throughput, and clay lump amount.