• 한국환경과학회지
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• 제12권3호
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• pp.345-358
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• 2003

Jindong bay at the northwestern part of Jinhae bay suffers from the occurrence of red tides in summer every year. In order to study the management methods of coastal environments, an ecological numerical model has been developed. The model experiments was forecasted that the load of nutrients from the land and field concentration will be cut down per 10% each. When we cut down 57.2% nitrogen load in the inner bay and 38.4% phosphorous load in the outer bay of bottom layer of the nutrients load from land and field concentration, the seawater quality standard levels up first grade. When we cut down 86.5% nutrients in the inner bay and 93.0% nutrients in the outer bay, the concentration of chlorophyll a decreases below 3.2 $\mu\textrm{g}$/(equation omitted)(an individual concentration of phytoplankton : 10,000cel1/ml), i.e. the red tides do not occur.

• Ecology and Resilient Infrastructure
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• 제3권1호
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• pp.1-7
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• 2016

최근 하천복원 사업은 하천의 이수 및 치수 기능과 함께 생태적 기능을 고려한 방향으로 진행되고 있다. 생태적 건강성과 다양성이 증대된 하천으로의 복원을 위해서는 하천 내 제방과 같은 종적구조물로 의해 차단된 공간에서의 수리수문 연결성 회복이 중요하다. 본 연구에서는 차단된 공간에서의 생태적 연결성 분석에 필요한 수리수문자료의 제공을 위한 첫번째 단계로써 강우에 의한 유역유출 및 하도흐름 해석이 동시에 가능한 1차원 수치모형을 개발하였고, 이를 청미천 유역에 적용하였다. 수치해석 결과는 실측 자료 및 타 모형의 수치해석 결과와 비교하였고, 그 결과 잘 일치함을 알 수 있었다. 본 연구의 결과는 생태적 변화를 예측할 수 있는 자료의 제공을 위해 장기적인 수리수문분석이 가능하도록 보완될 예정이다.

• 한국해양공학회지
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• 제22권5호
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• pp.75-82
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• 2008

As a basic study for establishing a countermeasure for an oxygen deficient water mass (ODW), we investigated the variation of ODW volume according to the enforced total pollution load management in Jinhae Bay. This study estimated the inflowing pollutant loads into Jinhae Bay and predicted the reduction in ODW by using a sediment-water ecological model (SWEM). The result obtained in this study are summarized as follows: 1) The daily average pollutant loads of COD, SS, TN, TP, DIN, and DIP inflowing into Jinhae bay in 2005 were estimated to be about 12,218 kg-COD/day, 91,884 kg-SS/day, 5,292 kg-TN/day, 182 kg-TP/day, 4,236 kg-DIN/day, and 130 kg-DIP/day. 2) The calculated results of the tidal current by the hydrodynamic model showed good agreement with the observed currents. Also, an ecological model well reproduced the spatial distribution of the water quality in the bay. 3) This study defined the ODWDI (ODW decreasing index) in order to estimate the ODW decreasing volume caused by a reduction in the inflowing pollutant loads. As a result, the ODWDI was predicted to be about 0.91 (COD 30% reduction), 0.87 (COD 50% reduction), 0.79 (COD 70% reduction), 0.85 (ALL 30% reduction), 0.66 (ALL 50% reduction), and 0.45 (ALL 70% reduction). The ODW volume was decreased 1.5 $\sim$ 2.6 times with a reduction in the COD, TN, and TP inflowing pollutant loads compared to a reduction in just the COD inflowing pollutant load. Therefore, it is necessary to enforce total pollution load management, not only for COD, but also fm TN and TP.

• 한국해양공학회지
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• 제22권2호
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• pp.34-41
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• 2008

As a basic study for developing a forecasting/estimating system that predicts water quality changes when Deep Sea Water (DSW) drains to the ocean after using it, this study was carried out as follows: 1) numerical simulation of the present state at DSW developing region in the East sea using SWEM, 2) numerical prediction of water quality changes by effluent DSW, 3) analysis of influence degree 'With defined DEI (DSW effect index) at F station. On the whole, when DSW drained to the ocean, Chl-a, COD and water-temperature were decreased and DIN, DIP and DO were increased by effluent DSW, and Salinity was steady. According to analysis of influence degree, the influence degree of DIN was the highest and it was high in order of Chl-a, COD, Water-temperature, DO, DIP and Salinity. The influence degree classified by DSW effluent position was predicted that suiface outflow was lower than bottom outflow. Ad When DSW discharge increased 10 times, the influence degree increased about $5{\sim}14$ times.

• KIEAE Journal
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• 제17권5호
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• pp.33-41
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• 2017

Purpose: Indoor air quality in residential buildings needs to be evaluated over the long term. In previous research, there has been an attempt to perform the health risk assessment of pollutants by using numerical models as a method of long-term evaluation. However, the numerical model of this precedent study has limitations that do not reflect the actual concentration distribution. Therefore, this study introduces the CRPS index, constructs a numerical model that can reflect the concentration distribution, and then presents a more accurate health risk assessment method using it. At this time, the pollutants are toluene, which is a typical material released from building materials. Method: CRPS index was applied to existing numerical model to reflect concentration distribution. This was used to calculate concentrations at adult breathing area and to use them for exposure assessment in a health risk assessment. After that, we entered adult data and conducted a health risk assessment of toluene. Results: The non-carcinogenic risk of toluene was calculated to be 0.0060. This is 5% smaller than the existing numerical model, meaning that it is more accurate to predict the pollutant risks. This value is also lower than the US EPA reference value of 1. Therefore, under the conditions of this study, long-term exposure of adults to toluene has no impact on health.

• 한국수산과학회지
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• 제54권5호
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• pp.787-797
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• 2021

Yellowtail Seriola quinqueradiata tagged with a Pop-up Satellite Archival Tag (PSAT) was released off the coast of near the Moseulpo, Jeju Island and the ecological data during about 40 days was obtained. However, it is difficult to determine the spatial location of underwater ecological data. To improve the accuracy of estimating the Yellowtail migration route using temperature, suitable background field of the oceanic environment data was evaluated and used for input data. After developing of the tracking algorithm for migration route estimation, three experiment cases were estimated with ecological data among the surface layer, the mixed layer, and the whole water column. All tracking experiments move from western to eastern Jeju Island. Additionally, tracking experiment using 3D ocean numerical model reveal that it is possible to estimate the migration route using the fish ecological data of the entire water column. Therefore, using a large number of ecological data and a high-accuracy ocean numerical model to estimate the migration route seems to be a way to increase the accuracy of the tracking experiment. Moreover, the tracking algorithm of this study can be applied to small pelagic fishery using small archival electronic tags to track the migration route.

• Water Engineering Research
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• 제7권1호
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• pp.9-20
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• 2006

The watersheds are functional geographical areas that integrate a variety of environmental and ecological processes and human impacts on landscapes. Geographical assessments using GIS recognize the relationship between interdependence of resources and ecological/environmental components in watersheds. They are useful methodology for viable long term natural resource management. This paper performs through the using hydrological analyses, landscape ecological analyses, remote sensing, and GIS. Indicators are items or measures that represent key components of the small watersheds, and they are developed to be evaluated. Some indicators are described that they represent watershed condition and trend as well as focus on physical, biological and chemical properties of small watershed. Also, ecological functions such as stability, resilience, and sensitivity are inferred from them. The model implemented in GIS allows to reflect the ecological and hydrological functioning of watershed. Methodology from image analysis, landscape ecological analysis, spatial interpolation, and numerical process modeling are integrated within GIS to provide assessment for eco-logical/environmental condition. Results are described from the small watershed of Gwynns Falls in Baltimore County and Baltimore City, Maryland, an area of about 66.5 square miles. The small watershed within Gwynns Falls watershed are subject to a number of land-use. But it is predominantly urban, with significantly lesser amounts of forest and agriculture. The increasing urbanization is ass-coiated with ecological/environmental impacts and citizen conflicts.

• 한국해양환경ㆍ에너지학회지
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• 제4권2호
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• pp.3-14
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• 2001

저질로부터 용출되는 영양염부하가 내만의 수질오염에 미치는 영향을 예측하기 위하여 수층과 저질간의 물질순환과정을 고려한 수-저질생태계모델(SWEM)을 개발하였다. SWEM모델은 유동을 예측하는 수리역학모델과 수층의 생태계순환 및 저질로부터의 영양염용출과정을 고려하여 수-저질간의 물질순환과정을 예측하는 생태계모델의 2개의 서브모델로 구성되어 있으며, 수치모형실험은 실시간에 의한 유동과 수질예측 계산을 실시하였다. 본 모델을 일본 博多灣에 적용하며 대상해역의 부영양화과정 및 영양염의 물질순환과정을 수치예측하고, 저질로부터 용출되는 영양염이 만내의 수질변화에 미치는 영향에 대하여 검토하였다. 모델에 의한 博多灣의 유통계산견과는 조류, 수온ㆍ염분의 관측치와 잘 일치하였으며, 물질순환예측의 계산치는 만내 수질관측치를 양호하게 재현하였다. 또한, 博多灣의 영양염 플럭스의 예측결과로부터 저질로 부터 용출하는 영양염 플럭스는 수질변화에 크게 영향을 미치고 있는 것 으로 나타났다.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 추계학술발표회
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• pp.248-248
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• 2017

• 대한수학회지
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• 제54권1호
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• pp.1-16
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• 2017

In this paper we study a four dimensional tourism-based social-ecological dynamical system. In fact we analyse tourism profitability, compatibility and sustainability by using bifurcation theory in terms of structural properties of attractors of system. For this purpose first we transformed it into a three dimensional system such that the reduced system is the extended and modified model of the previous three dimensional models suggested for tourism with the same dimension. Then we investigate transcritical, pitchfork and saddle-node bifurcation points of system. And numerically by finding some branches of stable equilibria for system show the profitability of tourism industry. Then by determining the Hopf bifurcation points of system we find a family of stable attractors for that by numerical techniques. Finally we conclude the existence of these stable limit cycles implies profitability and compatibility and then the sustainability of tourism.