• 한국환경과학회지
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• 제18권12호
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• pp.1369-1381
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• 2009

The simultaneous determination of residual pesticides was developed using a gas chromatography. In this study, a simple and reliable methodology was improved to detect 175 kinds of residual pesticides by a liquid-liquid extraction procedure, followed by chromatographic analysis by gas chromatography. The 175 kinds of residual pesticides was classified into 4 groups according to the chemical structure, column type, resolution and sensitivity. The soybean sample selected for recovery experiment was not detected any pesticides. The recovery rates were ranged from 70.6% to 119.7% in most pesticides. The relative standard deviation (RSD 0.3~5.6%) was lower than 5.6% in all cases. The limits of detection (LOD) was lower than the maximum residue levels established by Korean legislations. The method has been successfully applied to the analysis of approximately 130 real samples.

• Bulletin of the Korean Chemical Society
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• 제24권11호
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• pp.1571-1574
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• 2003

This paper describes an inductively coupled plasma emission spectrometric method for the analysis of Fe in rat plasma. Calibration curves were obtained in the range of 0.125-1.50 ${\mu}g{\cdot}mL^{-1}$. The relative standard deviation ranges from 5.93% to 6.80%, and accuracy was between 87.6 and 102.0%. Dilution with water had no influence on the performance of the method, which could then be used to quantify Fe concentration in plasma up to 0.50 ${\mu}g{\cdot}mL^{-1}$. The limit of quantification was 0.10 ${\mu}g{\cdot}mL^{-1}$. At this level, the average relative standard deviation was 6.8%. The results indicate that the method meets the accuracy and precision requirements for the pharmacokinetic studies. The Fe concentration in rat plasma was measured and the main pharmacokinetic parameters were calculated by Topfit 2.0 (GmbH. Shering AG, Godecke AG, Germany).

• 대한음성학회지:말소리
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• 제46호
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• pp.103-115
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• 2003

In this paper, we proposed Background Model Set algorithm used in the speaker verification to improve calculating confidence measure(CM) in speech recognition. CM is to display relative likelihood between recognized models and antiphone models. In previous method calculating of CM, we calculated probability and standard deviation using all phonemes in composition of antiphone models. At this process, antiphone CM brought bad recognition result. Also, recognition time increases. In order to solve this problem, we studied about method to reconstitute average and standard deviation using BMS algorithm in CM calculation.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2003년도 5월 학술대회지
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• pp.79-82
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• 2003

In this paper, we proposed Backgorund Model Set algorithm for the speaker verification to improve the shortcoming of calculating process in conventional confidence measure(CM). CM is to display relative likelihood between recognized models and unrecognized models. Unrecognized models is known as antiphone models. Calculate probability and standard deviation using all phonemes at process that compose antiphone model. At this process, antiphone CM brought bad result. Also, recognition time increases. In order problem, we studied about method to reconstitute average and standard deviation taking BMS algorithm using antiphoneme that near phoneme of CM calculation.

• 분석과학
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• 제13권2호
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• pp.179-188
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• 2000

대기환경시료인 도시분진시료와 인공적으로 준비한 휠터상 도시분진시료중의 미량원소를 중성자방사화분석법을 사용하여 비파괴 분석하였다. 분석정도관리를 위하여 미국 표준기술원의 인증표준시료 (Urban Dust, NIST SRM 1648)를 이용하였다. 37종의 검출된 원소의 상대오차와 상대 표준편차를 계산하였으며 각각 10%와 15%이내이었다. 도시분진시료로부터 29종의 원소, 휠터상 도시분진시료로부터 21종의 원소를 정량하였다. 측정결과의 신뢰도 및 숙련도 평가를 위하여, 중성자방사화분석법, 하전입자유도 X-선방출분광법, X-선 형광분석법과 원자흡수분광법을 이용한 세계 39개 실험실이 참여한 실험실간 비교시험에 참여하였으며 수집된 결과를 통계처리하였다. 평균값과 표준편차로 계산한 z-score는 몇개의 원소를 제외하고 모두 -1

• 한국토양비료학회지
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• 제32권3호
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• pp.268-273
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• 1999

토지이용 유형과 유효인산 함량이 다양한 56개 토양을 대상으로 범용 분광광도계를 사용한 Lancaster법과 분석과정 및 측정과정을 간편화시킨 Soiltek$^{(R)}$ KA-1에서 제시하는 방법으로 측정한 유효인산함량에 대하여 정확도 및 정밀도를 비교 분석하였다. 두 방법으로 분석된 인산함량은 고도의 유의성 있는 정의상관 ($r=0.998^{***}$)을 보였으며, 기울기는 0.97로 거의 일치하여 두 방법간의 정확성은 차이가 없었다. 또한, 두 방법으로 측정된 인산함량 분석결과의 표준편차, CV, 상대정밀도(RS)는 거의 차이가 없으므로 정밀도에서도 차이가 없었다. 따라서, 분석과정 및 기기조작의 편리성 및 신속성을 고려한다면 Soiltek$^{(R)}$ KA-1에서 제시하는 방법으로 유효인산 함량을 측정하는 것도 유용한 방법이라고 생각된다.

• 한국수자원학회논문집
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• 제35권5호
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• pp.575-581
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• 2002

본 연구에서는 강수의 계절성에 따라 면적평균강수의 추정오차가 어떻게 달라지는지를 평가하였다. 공간상관을 고려하는 경우와 고려하지 않는 경우 모두를 다루었으며, 각각의 경우에 대해 추정오차의 변화를 살펴보았다. 유사한 경우로서 계절성을 무시하고 누가시간을 증가시켜 추정오차가 어떻게 변하는지도 살펴보았다. 본 연구는 금강유역에 적용하였으며 30년 이상의 일 강수 기록을 가진 28개 지점의 자료를 이용하였다. 본 연구의 결과를 정리하면 다음과 같다: (1) 월 단위의 면적평균강수량에 대한 추정오차는 대체로 강수량에 비례하여 나타나며, 따라서 강한 계절성을 나타낸다. 그러나 이를 평균 강수량으로 나눈 상대오차는 1월과 12월을 제외하면 대략 5 - 8% 정도로 유사한 값을 보인다. (2) 연 강수량에 대한 추정오차는 연강수량의 3% 정도인 것으로 나타났다. (3) 그러나, 강수량이 아닌 강수량의 표준편차를 기준으로 삼는 경우 면적평균강우의 추정오차는 월 단위 및 년 단위에서 동일하게 표준편차의 11% 정도로 계산된다. (4) 마지막으로, 공간상관을 고려하지 않는 경우의 추정오차는 고려하는 경우의 2배 정도까지 커짐을 확인할 수 있었다.

• 한국대기환경학회지
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• 제15권4호
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• pp.495-503
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• 1999

Airborne particulate matter $(PM_{10})$ collected using high volume air sampler and silica fiber filter were analyzed by Instrumental Neutron Activation Analysis(INAA), Inductively Coupled Plasma Atomic Emission Spectrometry(ICP-AES) and Atomic Absorption Spectrometry(AAS), and the results were compared with each other. 30~40 trace elements in environmental standard reference materials(NIST SRM 1648 and NIES CRM No.8) were analyzed for the analytical quality control. The relative error for two-third of elements detected was less than 10%, and the standard deviation was less than 15%. During the sampling period for 24 hours, the mass concentration of total suspended particulate was 36.1$\mu\textrm{g}$/㎥ and the value is lower than the critical level in Korea. In the results of NAA, the elements of Al, As, Ba, Fe, La, Mg, Na, Sb, Zn were well agreed with those of other methods. In statistical estimation between different methods, the deviation of Al, Ba, Cr, Fe was less than 10% and quite reliable.

• Asian-Australasian Journal of Animal Sciences
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• 제26권6호
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• pp.864-873
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• 2013

In developing countries, biogas energy production is seen as a technology that can provide clean energy in poor regions and reduce pollution caused by animal manure. Laboratories in these countries have little access to advanced gas measuring equipment, which may limit research aimed at improving local adapted biogas production. They may also be unable to produce valid estimates of an international standard that can be used for articles published in international peer-reviewed science journals. This study tested and validated methods for measuring total biogas and methane ($CH_4$) production using batch fermentation and for characterizing the biomass. The biochemical methane potential (BMP) ($CH_4$ NL $kg^{-1}$ VS) of pig manure, cow manure and cellulose determined with the Moller and VDI methods was not significantly different in this test (p>0.05). The biodegradability using a ratio of BMP and theoretical BMP (TBMP) was slightly higher using the Hansen method, but differences were not significant. Degradation rate assessed by methane formation rate showed wide variation within the batch method tested. The first-order kinetics constant k for the cumulative methane production curve was highest when two animal manures were fermented using the VDI 4630 method, indicating that this method was able to reach steady conditions in a shorter time, reducing fermentation duration. In precision tests, the repeatability of the relative standard deviation (RSDr) for all batch methods was very low (4.8 to 8.1%), while the reproducibility of the relative standard deviation (RSDR) varied widely, from 7.3 to 19.8%. In determination of biomethane concentration, the values obtained using the liquid replacement method (LRM) were comparable to those obtained using gas chromatography (GC). This indicates that the LRM method could be used to determine biomethane concentration in biogas in laboratories with limited access to GC.

• Journal of Forest and Environmental Science
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• 제32권3호
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• pp.280-290
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• 2016

Stem diameter variability is an essential inventory result that provides useful information in forest management decisions. Little has been done to explore the modelling potentials of standard deviation (SDD) and coefficient of variation (CVD) of diameter at breast height (dbh). This study, therefore, was aimed at developing and testing models for predicting SDD and CVD in stands of Pinus caribaea Morelet (pine) in south west Nigeria. Sixty temporary sample plots of size $20m{\times}20m$, ranging between 15 and 37 years were sampled, covering the entire range of pine in south west Nigeria. The dbh (cm), total and merchantable heights (m), number of stems and age of trees were measured within each plot. Basal area ($m^2$), site index (m), relative spacing and percentile positions of dbh at $24^{th}$, $63^{rd}$, $76^{th}$ and $93^{rd}$ (i.e. $P_{24}$, $P_{63}$, $P_{76}$ and $P_{93}$) were computed from measured variables for each plot. Linear mixed model (LMM) was used to test the effects of locations (fixed) and plots (random). Six candidate models (3 for SDD and 3 for CVD), using three categories of explanatory variables (i.e. (i) only stand size measures, (ii) distribution measures, and (iii) combination of i and ii). The best model was chosen based on smaller relative standard error (RSE), prediction residual sum of squares (PRESS), corrected Akaike Information Criterion ($AIC_c$) and larger coefficient of determination ($R^2$). The results of the LMM indicated that location and plot effects were not significant. The CVD and SDD models having only measures of percentiles (i.e. $P_{24}$ and $P_{93}$) as predictors produced better predictions than others. However, CVD model produced the overall best predictions, because of the lower RSE and stability in measuring variability across different stand developments. The results demonstrate the potentials of CVD in modelling stem diameter variability in relationship with percentiles variables.