• 한국해양환경ㆍ에너지학회지
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• 제3권1호
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• pp.52-61
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• 2000

제주도 남부연안해역을 대상으로 1997년 7월부터 1598년 6월 까지 매월 현장 조사와 수질 분석을 실시하였고, 생태계 모델을 이용한 시뮬레이션을 통하여 용존무기질소(DIP), 화학적 산소 요구량(COD) 및 용존산소(DO)의 수층별 분포를 재현하였다. 그리고 제주도 남부연안해역의 환경용량을 산정하기 위하여 해역수질 환경기준을 만족하지 못하는 환경악화 상태를 예측하는 수질 시뮬레이션이 실시되었으며, 이러한 예측 시뮬레이션은 생태계 모델을 이용하여 모델 해역으로 유입하는 주요 하천의 오염부하를 정량적으로 조절하면서 실시되었다. 그 결과 모델 해역으로 유입하는 4개 오염원으로부터의 오염부하가 증가할수록 오염원에 인접한 주변 해역에서 DIN, DIP 및 COD의 농도가 더욱 증가하는 것으로 나타났다. 하천을 포함한 4개 오염원 모두로부터의 오염부하가 현재 부하의 3배에 해당하는 경우, 오염원에 인접한 해역에서의 DIN 농도가 해역수질 환경기준의 3등급 기준인 0.20mg/ℓ까지 증가하는 것으로 예측되었다. 또한 오염원 모두로부터의 오염부하가 현재 부하의 10배에 해당하는 경우, 오염원에 인접한 해역에서의 COD농도가 해역수질 환경기준의 1등급 기준인 1.0mg/ℓ까지 증가하는 것으로 예측되었다. 그리고 오염원 모두로부터의 오염부하가 현재 부하의 20배에 해당하는 경우, 오염원에 인접한 해역에서의 DIP 농도가 해역수질 환경기준의 2등급 기준인 0.015mg/ℓ까지 증가하는 것으로 예측되었다.

• 한국수산과학회지
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• 제34권4호
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• pp.348-354
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• 2001

This study was conducted to estimation of change characteristics for water quality by the dyke gate operation in the Keum River estuary. The estimation data made use of surveyed data in Keum River estuary by NERDI (National Fisheries Research and Development Institute) during $1990\~1999$. Shown to compare water quality changes at st. A and st. D in Figure 1, the concentrations of TSS, COD and nutrients at st. A were as high as about $2\~4$ times than those at st. D due to affection of fresh water discharge in the Keum River. The percentages of water quality change at surface water by dyke gate operation in the Keum River estuary were shown that TSS (Total Suspended Solid) was decrease to $56\%,\;47\%$ at st. A and D, and COD (Chemical Oxygen Demand) was increase to $68\%,\;71\%$ at st. A and D, respectively. The changes percentage of DIN (Dissolved Inorganic Nitrogen) by dyke gate operation in the Keum River estuary were increase high to $95\%$ at surface water and $7\sim30\%$ at bottom water, but those of DIP (Dissolved Inorganic Phosphorus) were increase to $2.8\sim8.6\%$ at surface water and $28\%$ at bottom water. The range of fluctuation for water quality at each station by dyke gate operation has shown that salinity and TSS are little better than before dyke gate operation, but COD show highly fluctuation. Also we studied estimation of characteristics of water quality change by the season, COD was increased except the summer, TSS was decreased to all season. DIN was increased to about $61\sim172.1\%$ for all season, but DIP was increased to the spring and decreased to the autumn, DIN enrichment in the estuary by dyke gate operation are interpreted to improvement of organic matter decomposition and nitrification by increasing the residence time and to increase nutrient flux in sediments due to decreasing dissolved oxygen and increasing a deposit matter.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1675-1682
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• 2017

This paper deals with three dimensional orientation estimation algorithm for an attitude and heading reference system (AHRS) based on nine-axis inertial/magnetic sensor signals. In terms of the orientation estimation based on the use of a Kalman filter (KF), the quaternion is arguably the most popular orientation representation. However, one critical drawback in the quaternion representation is that undesirable magnetic disturbances affect not only yaw estimation but also roll and pitch estimations. In this paper, a sequential direction cosine matrix-based orientation KF for AHRS has been presented. The proposed algorithm uses two linear KFs, consisting of an attitude KF followed by a heading KF. In the latter, the direction of the local magnetic field vector is projected onto the heading axis of the inertial frame by considering the dip angle, which can be determined after the attitude KF. Owing to the sequential KF structure, the effects of even extreme magnetic disturbances are limited to the roll and pitch estimations, without any additional decoupling process. This overcomes an inherent issue in quaternion-based estimation algorithms. Validation test results show that the proposed method outperforms other comparison methods in terms of the yaw estimation accuracy during perturbations and in terms of the recovery speed.

• 한국수산과학회지
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• 제31권2호
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• pp.176-185
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• 1998

서식 환경 조사 결과 수온은 1992년에는 웅촌이, 1993 년에는 송도가 높았으며, 염분은 1992년 1월에서 5월을 제외하고는 송도 양식장이 더 높았다. 부유물질과 chlorophyll a 함량 및 저질내 COD는 송도가 높았고, DO, DIP, DIN 및 저질내 총황화물은 웅촌이 높았다. 피조개의 성장과 생리 상태를 분석한 결과, 성장, 연체부지수, 체내 글리코겐 함량과 헤모글로빈 함량 모두 송도의 피조개가 높은 수치를 나타내었다. 또한 송도의 피조개가 생식소 발달도 빨랐다. 본 시험에서 피조개 성장과 생리상태에 영향을 미치는 가장 큰 환경 요인은 먹이생물의 양과 저질의 총황화물량으로 추정되었다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.150-153
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• 1997

The proposed tracking algorithm approaches geometrical method or position, direction, width of vessel. This algorithm using continuity of vessel in spatial coordinates used to determine direction of the center point, after estimating boundary point in dynamic region. Therefore the tracking of vessel's contour is tracked contour as direction of entire contour in coronary artery. This algorithm is automatically processed by DIP as a compared with conventional method, because searching area varies adaptively to allocate searching region from extracted information at past. And ML estimation expressed robust method or angiography as evaluating sample values after preprocessing.

• 한국환경과학회지
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• 제12권3호
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• pp.299-306
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• 2003

The purpose of this study is to investigate the characteristics of water quality in Jeju harbor and to estimate pollutant loadings discharged into Jeju Harbor. To know characteristics of water quality in Jeju harbor, and pollutant loadings of Sanzi river, we have investigated from August, 2000 to May, 2001. The results showed that the concentrations of COD, DIN and DIP were in the range of 1.00∼4.85 mg/L (mean 2.15 mg/L), 2.14∼74.0 $\mu\textrm{g}$-at/L(mean 12.20 $\mu\textrm{g}$-at/L) and 0.52∼4.00 $\mu\textrm{g}$-at/L(mean 1.18 $\mu\textrm{g}$-at/L), respectively. These values were under III class of seawater quality criteria. The ratio of nitrogen to phosphorus was lower than 16 except for Station 1 in Jeju harbor. Therefore, nitrogen was playing an important role in phytoplankton growth as limiting factor in Jeju harbor. The mean values of eutrophication index were exceeding 1, which was the eutrophication criteria. The results of estimating pollutant loadings at Sanzi river are 0.30 ton/day for COD, 300 kg/day for DIN and 18.0 kg/day for DIP, respectively.

• 한국환경과학회지
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• 제11권9호
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• pp.945-954
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• 2002

The objective okgf this study is understanding and evaluation of temporal and spatial variation of pollutant loads by input sources for water quality management in Kamak Bay. Flow rate of rivers and ditches ranges from about $2,592-63,072m^3/d$ in October to $864-55,296m^3/d$ in January. In particular, the R2 predominated flow rate among input sources. Total COD, BOD, DIN and DIP loadings in January were about 896kg/d, 718kg/d, 2,152kg/d, and 154kg/d, respectively, which exceeded those of October. Lower POC/TOC levels are estimated in R2, and also in October. Temporal variation of pollutant loads were closely related to the human activity. Total discharging loadings of BOD, TN and TP by unit loading estimation were 4,993.0kg/d, 2,558.7kg/d, and 289.2kg/d, respectively, and were mainly affected by the population. Runoff ratio of BOD was about 0.14 in January Mean $NH_4^＋_-N$ and $PO_4\;^{3-}-P$ loadings from sediment were 16.23mg/$m^2$/d and 7.26mg/$m^2$/d, respectively. For the improvement of water quality in this area, not only pollutant loads of rivers and ditches but also benthic flux from sediment should be reduced within the limits of the environmental capacity.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1990년도 춘계학술대회
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• pp.47-50
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• 1990

In this study, the degree of spectral transfer to lower frequency caused by accumulation of Latic acid inside the muscle is estimated the convintional dip analysis, zero-crossing method and FFT method have intrinsic errors and estimation problems in case of severe noise. The new spectral analysis method using "$2^{nd}$ order Maximum Entropy Method" was applied to estimate mean frequency and we confirmed that this new method yields fast and reliable estimation over the FFT method.

• Journal of Positioning, Navigation, and Timing
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• 제13권1호
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• pp.63-73
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• 2024

NeQuick G is the ionosphere model utilized by Galileo single-frequency users to estimate the ionospheric delay on each user-satellite link. The model is characterized by the effective ionization level (Az) index, determined by a modified dip latitude (MODIP) and broadcast coefficients derived from daily global space weather observations. However, globally fitted Az coefficients may not accurately represent ionosphere within local area. This study introduces a method for regional ionospheric modeling that searches for locally optimized Az coefficients. This approach involves fitting TEC output from NeQuick G to TEC data collected from GNSS stations around Korea under various ionospheric conditions including different seasons and both low and high solar activity phases. The optimized Az coefficients enable calculation of the Az index at any position within a region of interest, accounting for the spatial variability of the Az index in a polynomial function of MODIP. The results reveal reduced TEC estimation errors, particularly during high solar activity, with a maximum reduction in the RMS error by 85.95%. This indicates that the proposed method for NeQuick G can effectively model various ionospheric conditions in local areas, offering potential applications in GNSS performance analyses for local areas by generating various ionospheric scenarios.

• 한국지반환경공학회 논문집
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• 제9권5호
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• pp.61-69
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• 2008

일반적으로 암반사면의 안정성을 평가하는 방법으로는 평사투영해석, 한계평형해석, 수치해석, 안정성 평가표에 의한 방법 등 여러 가지 방법이 이용되고 있다. 이 중 안정성 평가표에 의한 방법은 평가법의 제안기관이나 자국의 특성에 따라 그 평가항목이 상이하며, 또한 안정성 평가표상의 개개의 평가항목에 대한 연구는 미흡한 실정이다. 본 연구에서는 315개소의 고속도로 암반사면 분석자료를 이용하여 일반적으로 사용되고 있는 암반사면의 안정성 평가항목중 기하학적 형상(사면높이, 사면경사 및 경사방향, 주불연속면의 경사 및 경사방향, 사면과 주불연속면의 방향차이) 및 지형학적 특성(지형의 집수가능성, 상부자연사면 경사, 사면형상)에 대한 이상치(abnormal value) 분석을 통하여 암반사면 안정성 평가항목의 유효성을 평가하였다.