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        검색결과 7

        1.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 인공지능기법을 이용하여 진동만의 용존산소량 예측을 하였다. 관측자료에 존재하는 결측 구간을 보간하기 위해 양방향재귀신경망(BRITS, Bidirectional Recurrent Imputation for Time Series) 딥러닝 알고리즘을 이용하였고, 대표적 시계열 예측 선형모델인 ARIMA(Auto-Regressive Integrated Moving Average)과 비선형모델 중 가장 많이 이용되고 있는 LSTM(Long Short-Term Memory) 모델을 이용 하여 진동만의 용존산소량을 예측하고 그 성능을 평가했다. 결측 구간 보정 실험은 표층에서 높은 정확도로 보정이 가능했으나, 저층에서는 그 정확도가 낮았으며, 중층에서는 실험조건에 따라 정확도가 불안정하게 나타났다. 실험조건에 따라 정확도가 불안정하게 나타났다. 결과로부터 LSTM 모델이 중층과 저층에서 ARIMA 모델보다 우세한 정확도를 보였으나, 표층에서는 ARIMA모델의 정확도가 약간 높은 것으로 나타났다.
        4,000원
        2.
        2013.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        제주연안선 부근에 밀집된 육상양식장 배출구 주변 4개 해역(애월리, 행원리, 표선리, 일과리)에서 수질환경의 시공간적 변화에 영향을 미치는 요인을 파악하기 위해 2010년 2월부터 2011년 12월까지 격월로 총 12회 조사하였다. 주성분 분석 결과 조사해역에서 연중 영양염의 분포는 염분과의 관련성 없이 배출구로부터 공급되는 물질에 의해 영양염의 농도가 조절되어, 연안에서 외해역으로 갈수록 농도구배가 감소하는 특징을 나타냈다. 특히 용존무기질소의 경우는 배출구와 인접한 해역에서는 부영양상태로 인에 비해 질소가 과잉되고 있었다. 유기물의 분포는 담수유입량이 증가하는 고수온기에 증가하는 경향을 보였다. 식물플랑크톤의 생물량 변화는 애월 및 행원해역은 담수유입과 관련된 기상요인(기온 및 강우), 표선 및 일과는 영양염의 인위적 공급요인(양식장 배출수)에 의한 영향을 주로 받는 것으로 나타났다. 특히, 배출구로부터 직선거리 약 300 m 및 수심 10 m이내 해역의 표ㆍ저층에서는 고영양염 농도 분포가 지속되고 있어, 부영양화 과정에서 발생하는 문제를 직ㆍ간접적으로 받을 수 있는 가능성을 나타냈다. 육상양식장의 운영 시 취수지점이 배출수의 영향을 받는 지점에 위치할 경우 사육수질의 문제가 발생할 수 있다.
        4,300원
        3.
        2020.03 KCI 등재 서비스 종료(열람 제한)
        Residence time is defined as the time taken for a material in a system to leave the system. The residence time characteristics in shellfish aquaculture determine the dispersion of excretion from aquaculture farms, along with the supply of food by seawater exchange. In this study, we estimated the spatial distribution of average residence time in the shellfish farming area using a particle tracking model. As a result, a relatively short average residence time of about 20 days or less was calculated in most areas, but an average residence time of more than 40 days was calculated in the inner areas. Relatively long average residence times were calculated along the west coast compared to the east coast, with the longest average residence time of more than 50 days in the northwestern areas. It can be inferred that the disturbance of the benthic ecosystem caused by shellfish farms is likely to be large because of the relatively weak dispersion of excrement from shellfish farms located on the west coast, especially in the northwest region. This distribution of average residence time is important for understanding the potential effects of seawater exchange on the environmental sustainability of shellfish farms, along with the seawater circulation characteristics of Jaran Bay.
        4.
        2017.10 KCI 등재 서비스 종료(열람 제한)
        Recently, the air quality issue came to the fore to the occupants of indoor areas with the detection of a large amount of indoor air pollutants such as formaldehyde that causes headache and atopic dermatitis. In order to address this issue, the use of indoor air purifying plants is considered positively as an ecological improvement option. However, the objective performance verification on indoor air-conditioning air volume has not been sufficient. This study aims to verify possible linkage with a building’s air conditioning equipment in order to optimize indoor air-conditioning effects by vegetation bio-filters. To this end, 4 different types of air filter material and AHU (Air Handling Unit) system were linked under air conditions of total wind volume of 400, 600, 800, 1,000 CMH and pressure loss by material was monitored objectively. Finally, material-specific power consumption for system operation was calculated to review energy efficiency. As for pressure loss by material, in terms of total wind volume of 800±1.8 CMH, Pre filter was lowest at –11.69 mmAq and LMF-based vegetation mat was highest at –219.94 mmAq. Based on this, as for material-specific power consumption, the Pre filter, which has the lowest pressure loss, was expected to have power consumption 94.7% lower than the LMF-based vegetation mat.
        5.
        2017.10 KCI 등재 서비스 종료(열람 제한)
        People today spend 80% of their time indoors and have been showing keen interests in air quality since 2015 due to harmful chemical issues such as humidifier disinfectants. Although plant-based air purification method is widely known to the public, its objective performance and air-conditioning efficiency have been limited. In particular, in the case of publicly used places frequented by many and unspecified persons, high air-conditioning wind volume is required and it is difficult to secure the required total wind volume with the current air purification method using plants. Therefore, in order to secure air-conditioning wind volume when linked with plants, this study aims to verify stability in using vegetation units that can be linked with building air-conditioning equipment. To this end, vegetation units and AHU were linked for 40 hours under no irrigation conditions and ecological environmental changes were monitored objectively. Pressure loss by total wind volume of vegetation units was verified, and soil moisture, Chlorophyll, and FVC were monitored. First, soil moisture was converged to 0% at a spot where wind volume is concentrated in vegetation units. In both of two types of tree species, chlorophyll showed a change of 1.2 - 2.9 SPAD and FVC showed a change of 4-29% after the experiment.
        6.
        2013.07 KCI 등재 서비스 종료(열람 제한)
        The aim of this study was to investigate the accumulation of metallic elements and the control effect of marine pollution caused by ocean dumping in the sediments at a waste disposal area in the Yellow Sea. In July 2009, concentrations of organic matter and metallic elements (Al, Fe, As, Cd, Cr, Co, Hg, Ni, Mn, Pb, and Zn) were measured in surface sediments at the site. The ignition loss (IL) in the surface sediments showed a mean value of 15.4%, about 1.5 times higher than the mean value of the sediments in the coastal areas of Korea. The chemical oxygen demand (COD) at some disposal sites exceeded 20 ㎎ O2/g·dry, which signifies the initial concentration of marine sediment pollutants in Japan. The disposal sites contain higher concentrations of Cr, Cu and Zn than the sediments of bays and estuaries that might be contaminated. The magnitude of both metal enrichment factors (EF) and adverse biological effects suggest that pollution with Cr and Ni occurred due to the dumping of waste in the study area. In addition, the geoaccumulation index (Igeo) showed that the surface sediments were moderately contaminated. By the mid-2000s, when the amount of waste dumped at this site was the highest, the concentration of metallic elements was higher than ever recorded. On the other hand, in 2008-09, the need for environmental management was relatively low compare with the peak. As a result, the quality of marine sediment has been enhanced, considering the effect of waste reduction and natural dilution in the disposal area.
        7.
        2005.08 KCI 등재 서비스 종료(열람 제한)
        For the sustainable management of marine ecosystem in Masan Bay, we have to assess the carrying capacity and standard of target water quality. In this research, we assume that all pollutants loads are treated in Dukdong sewage treatment plant, then we simulate the physical-biological model for prediction water quality for the achievement of standard water quality. In 2001 year, for the achievement of COD 2.5 mg/L, we need to reduce COD 90 %, nitrogen 30 %, phosphate 90% than that of the present value. According to these results, the water quality of sewage treatment plant is required to treat COD 13.5 mg/L, nitrogen 33.3 mg/L, phosphate 6.0 mg/L. If the sewage treatment plant will be expanded much larger in 2011, it will need to be treated in COD 6.6 mg/L, nitrogen 2.5 mg/L, phosphate 5 mg/L for the achievement of water quality standard in COD 2.5 mg/L.