• 자원환경지질
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• 제32권6호
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• pp.633-644
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• 1999

Gully pot is a part of urban darainage system to butter the runoff water fluxes from road to rivers and to minimize environmental pollution by prevending over the surrounding area. A series of studies have been carried out concerning the physicochemical characteristics of the sewage sludge sediments sttling down in such a gully pot in order to over to evaluate the contamination for heavy metals such as pb, Zn, Cu and Cd. The roadside soil and sewage sludge samples from gully pots were characterized by XRD analyses and sequential extraction : Zn 2595.7$\mu$g/g; Cd9.8$\mu$/g; Cu602.5$\mu$g/g; Pb260.0$\mu$g/g),because of a long-term accumulation of vehicle- and industrial-related pollutants. Mean Zn concentration in Yeouido (3873$\mu$g/g) and Junggu(3262$\mu$g/g)areas are 4-5 times higher than those in Dobonggu area, suggesting that Zn may be derived from automobile traffic (including the rubber of automobile tires). The mean concentrations of Cu and Cr are very significantly high in Junggu and Gurogu areas, possibly due to the industrial activities in these areas. The low Pb levels throughtotut the whole study areas in Seoul can be accounted for the use of unleaded gasoline since 1987. Sequential extraction experiments illustrate that a major part of Zn is bound to FII and FIII, representing about 88% of the total Zn concentration. Fraction IV, related to orgnic matter, is mostly significant for Cu accounting for 60% of the total Cu, and FII is next in importance. The main carriers of Pb are the fractions III, II and FIV, and in that order. The behavior of Cd is quite different from other elements (Zn, Cu, Pb), and most of the Cd is associated with FV. Changes in the physicochemical environments (such as acidification) may result in severe environmental pollution of surface water and rivers with respect to heavy metals (especially Zn and Cu).

• 자원환경지질
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• 제52권2호
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• pp.141-158
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• 2019

경남에 소재하는 삼천포 및 하동 석탄 화력발전소 인근 농경지 토양을 대상으로 중금속 함량을 측정하였다. 삼천포지역 48개, 하동 지역 61개의 표토 및 심토를 대상으로 분석한 결과, Cu, Hg, Ni, Pb, Zn는 모두 토양오염 우려기준 미만으로 나타났으나 Cd는 삼천포 38개, 하동 13개 시료에서 우려기준을 초과하였다. 지질부하지수와 농축계수를 구한 결과 Cd는 높은 오염도를 보였으며 Cd와 Pb는 인위적 오염원에 의한 토양 내 농축인 것으로 보인다. 그러나 연속추출을 통해 중금속의 존재형태를 규명한 결과 Cd를 포함한 토양 내 중금속들은 대부분 용출 가능성이 매우 적은 형태로 존재하여 생물이용도가 낮게 나타났다. 이러한 결과는 석탄 화력발전소 인근 토양이 인위적인 요인으로 인해 Cd로 오염되었으나 인근 생태계로 유입될 가능성은 낮음을 의미한다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권1호
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• pp.8-16
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• 2021

This study has evaluated the stabilization of As contaminated paddy and cultivated soils by pot experiments for rice and lettuce. Various ratios of limestone (L) and steel slag (S) were mixed with the soils in each pot. The soils were taken from before and after pot experiments, and analyzed for As extracted by sequentially (Wenzel method) and totally (aqua regia method).. Paddy soils amended with L (0.5%) and L (1.0%) + S (1.0%) showed increasing fraction 2 (specifically bound As) compared with control soil. Arsenic concentrations in rice grain grown on the amended soils decreased 14% and 12% compared with those on the control soil, respectively. According to sequential extraction of As in cultivated soils, the fractions 1~3 were decreased due to stabilization of As by the soil amendment, especially for S (1.0%), S (3.0%) and L (1.0%) + S (1.0%). In addition, relatively low As concentrations were found in lettuce grown on amended soils with L (0.5%) and L (1.0%) + S (1.0%). Therefore, it can be suggested that soil amendments with L (0.5%) or L (1.0%) + S (1.0%) were suitable for enhancing stabilization of As in the study area.

• 한국환경농학회지
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• 제41권4호
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• pp.223-229
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• 2022

BACKGROUND: Mining activities, smelter discharges, and sludges are the major sources of heavy metal contamination to soils. The objective of this study was to determine the efficiency of magnetite and bottom ash derived from coal ash in remediating As-contaminated soil. METHODS AND RESULTS: An incubation experiment was conducted for 10 weeks. Magnetite and bottom ash at different rates and ratios were applied to each plastic bottle repacked with 1,000 g of dried As-contaminated soil. After 3-weeks of incubation, the concentrations of available As were measured by using Mehlich-3, SBET, and sequential extraction methods. All of the subjected soil amendments resulted in significant decreases in available As concentration compared to the controls. The addition of magnetite at the highest rate was the best to stabilize As in the soils; however, the values of As concentration varied with the extraction methods. CONCLUSION(S): To ensure the stabilization accuracy of heavy metals in soil, both single and sequential extractions are recommended. The magnetite derived from fly coal ash can also be applicable as a heavy metal stabilizer for the As-contaminated soil.

• 전자공학회논문지
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• 제51권7호
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• pp.60-68
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• 2014

최근 전자전 지원 시스템 분야에서는 TDOA(time difference of arrival)와 FDOA(frequency difference of arrival) 정보를 활용한 고 정밀 위치 추정 방법에 대한 연구가 활발히 진행되고 있다. TDOA/FDOA 위치 추정 시스템은 TDOA와 FDOA 정보를 추출하는 단계와 추출한 정보로부터 신호원의 위치를 추정하는 두 단계로 나뉘며, 정보 추출 단계에서 보편적으로 사용하는 알고리즘으로 CAF(complex ambiguity function) 기반 방법이 알려져 있다. 하지만 기존의 CAF 기반 알고리즘은 VHF 대역의 통신 신호로부터 TDOA 및 FDOA 정보를 추출하는 경우, 많은 연산량으로 인해 제한된 시간에 처리하기 어려운 단점이 있다. 따라서 본 논문에서는 통신 신호 기반 TDOA/FDOA 정보 추출을 연산량 측면에서 효율적으로 수행하기 위해 개선된 CAF 기반 순차 추정 알고리즘을 제안하고, 기존 CAF기반 알고리즘과 연산량을 비교 분석한다. 또한 제안한 알고리즘의 추출 성능을 검증하기 위해 CRLB(Cramer-Lao lower bound)를 이용해 유도된 이론적 한계 성능과 비교 분석한다.

• 한국지능시스템학회논문지
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• 제16권4호
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• pp.466-471
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• 2006

패턴 인식 문제에서 중요한 전처리 과정 중 하나는 특정을 선택하거나 추출하는 부분이다. 특정을 추출하는 방법으로는 PCA가 보통 사용되고 특정을 선택하는 방법으로는 SFS 나 SBS 등의 방법들이 자주 사용되고 있다. 본 논문은 진화 연산 방법으로써 비선형 최적화 문제에서 유용하게 사용되어 지고 있는 유전자 알고리즘을 특정 선택에 적용하는 유전자 알고리즘 특정 선택 (Genetic Algorithm Feature Selection: GAFS)방법을 개발하여 다른 특징 선택 알고리즘과의 비교를 통해 본 알고리즘의 성능을 관찰한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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• pp.1390-1403
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• 2016

Facial expression recognition (FER) plays a very significant role in computer vision, pattern recognition, and image processing applications such as human computer interaction as it provides sufficient information about emotions of people. For video-based facial expression recognition, depth cameras can be better candidates over RGB cameras as a person's face cannot be easily recognized from distance-based depth videos hence depth cameras also resolve some privacy issues that can arise using RGB faces. A good FER system is very much reliant on the extraction of robust features as well as recognition engine. In this work, an efficient novel approach is proposed to recognize some facial expressions from time-sequential depth videos. First of all, efficient Local Binary Pattern (LBP) features are obtained from the time-sequential depth faces that are further classified by Generalized Discriminant Analysis (GDA) to make the features more robust and finally, the LBP-GDA features are fed into Hidden Markov Models (HMMs) to train and recognize different facial expressions successfully. The depth information-based proposed facial expression recognition approach is compared to the conventional approaches such as Principal Component Analysis (PCA), Independent Component Analysis (ICA), and Linear Discriminant Analysis (LDA) where the proposed one outperforms others by obtaining better recognition rates.

• 한국농공학회논문집
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• 제59권5호
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• pp.41-49
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• 2017

This study was aimed to investigate the influence of cation exchange capacity (CEC) and application amounts of zeolite on the stabilization of heavy metals (As, Ni, Pb, and Zn) in upland soils. The upland soils were sampled from field near mines located in Gyeonggi Province. The CEC of zeolite was treated at three different levels, ie, low, medium, and high, while zeolite was amended with soils at the ratio of 0.1 % and 0.5 % as to soil weight. A sequential extraction was performed for the soil sampled at 1, 2 4, and 8 week after zeolite was added to the soil. The concentrations of Pb and Zn appeared to be high in the sampled soils. The mobility of heavy metals obtained from sequential experiments was as follows: Pb > Zn > Ni >As. Addition of zeolite to contaminated soils effectively reduced exchangeable and carbonate fractions but increased organic and residual fraction, indicating that zeolite is effective for immobilizing heavy metals in soils. The influence of incubation time on the metal stabilization was rather pronounced as compared to the application amount and CEC of zeolite.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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• pp.893-898
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• 1994

In this paper, the influence of voice source estimation and modeling on speech synthesis and coding is examined and then their new estimation and modeling techniques are proposed and verified by computer simulation. It is known that the existing speech synthesizer produced the speech which is dull and inanimated. These problems are arised from the fact that existing estimation and modeling techniques can not give more accurate voice parameters. Therefore, in this paper we propose a new voice source estimation algorithm and modeling techniques which can not give more accurate voice parameters. Therefore, in this paper we propose a new voice source estimation algorithm and modeling techniques which can represent a variety of source characteristics. First, we divide speech samples in one pitch region into four parts having different characteristics. Second, the vocal-tract parameters and voice source waveforms are estimated in each regions differently using sequential SVD. Third, we propose composite source model as a new voice source model which is represented by weighted sum of pre-defined basis functions. And finally, the weights and time-shift parameters of the proposed composite source model are estimeted uning EM(estimate maximize) algorithm. Experimental results indicate that the proposed estimation and modeling methods can estimate more accurate voice source waveforms and represent various source characteristics.

• 대한소아치과학회지
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• 제30권1호
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• pp.110-115
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• 2003

치외치(Dens evaginatus)는 조직 형태 분화기에 법랑기의 내측 법랑 상피가 외부로 과증식 되거나 치수 간엽 조직 이 국소적으로 과증식되어 나타난다. 치외치는 하악제 2소구치에서 가장 빈발하며 유전적 성향을 가지고 있다고 알려져 있다. 치아에 발생한 결절은 법랑질, 상아질, 치수 등의 정상 치아구조를 가지고 있으며 그 형태학적 특성으로 인해 저작에 의한 파절 또는 마모가 발생하여 미세한 치수노출이 발생할 수 있다. 이러한 치수노출에 의해서 치수염증, 치근단 병변, 치근 형성 중지 등이 생길 수 있으므로 조기에 발견하여 예방 및 조기치료를 시행하는 것이 중요하다. 만약 이미 감염이 진행되어 치근단 병변이 야기된 경우 적절한 근관 치료가 행해져야 하며 미완성 치근을 가지고 있는 경우가 대부분이므로 치근단 형성술을 병행해야 한다. 이에 저자는 치외치에 의한 치근단 병변을 주소로 내원하여 치근단 형성술을 시행한 언니의 증례와, 함께 내원하여 사전에 발견하고 점진적 삭제술을 시행하여 양호한 결과를 얻은 동생의 증례를 보고하는 바이다.