• Communications for Statistical Applications and Methods
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• 제16권3호
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• pp.421-428
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• 2009

범주형 자료의 시각화에서 범주가 많지 않은 경우에는 기존의 Hayashi의 수량화 제3방법을 이용하여 두변수의 범주들 사이의 연관성에 대한 시각화를 구할 수 있다. 그러나, Hayashi방법은 큰 빈도의 범주들보다 작은 빈도의 범주들을 두드러지게 수량화하므로 결과가 불안정하다는 문제점이 있다 (허명회와 이용구, 2006). 이 연구의 목적은 범주수가 "큰" 두 범주형 변수 R과 C에 대하여 각 변수 벌주들 사이의 연관성을 살펴보기 위한 시각화 방법을 제안하는 데 있다. 이를 위하여 우리는 2개 변수군 수치형 자료를 시각화하는 방법으로 제안된 허명회 등 (2007)의 PLS 시각화 방법을 범주형 자료에 적용하고자 한다. 즉, 범주형 변수 R과 C의 범주들 각각을 0/1로 더미 코드화하여 각각 R개와 C개의 범주군으로 변환한 다음 허명회 등 (2007)에서 제시한 PLS 시각화 방법을 적용하고자 한다. 이러한 방법은 Hayashi 수량화 방법의 문제점을 해결할 수 있을 뿐만 아니라 행변수와 열변수 각각이 여러 개의 범주형 변수들의 집합인 변수군의 경우에도 확대 적용 가능하다. 순치 예로서 German Credit 자료에서 10개 금융관련 변수의 34개 범주를 R로 간주하고 10개 사회인구적 변수의 46개 범주를 C로 간주하여 새 방법론을 적용해 보인다.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3727-3734
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• 2012

An analytical method has been developed for the rapid determination of perfluorinated compounds (PFCs) in human serum samples. The extraction and purification of PFCs from human serum were performed by the modified method of previous report. Ten PFCs were rapidly separated within 3.3 min by C18-monolithic column liquid chromatography (LC) and detected by electrospray ionization (ESI) tandem mass spectrometry (MS/MS) in negative ion mode. The runtime of PFCs on monolithic column LC was up to 4-fold faster than that on conventional column LC. The effect of triethylamine (TEA) to the mobile phase has investigated on the overall MS detection sensitivity of PFCs in ESI ionization. Quantification was performed by LC-MS/MS in multiple-ion reaction monitoring (MRM) mode, using $^{13}C$-labeled internal standards. Method validation was performed to determine recovery, linearity, precision, and limits of quantification, followed by, the analysis of a standard reference material (SRM 1957 from NIST). The overall recoveries ranged between 81.5 and 106.3% with RSDs of 3.4 to 16.2% for the entire procedure. The calibration range extended from 0.33 to 50 $ng\;mL^{-1}$, with a correlation coefficient ($R^2$) greater than 0.995 and the limits of quantification with 0.08 to 0.46 $ng\;mL^{-1}$. This approach can be used for rapid and sensitive quantitative analysis of 10 PFCs in human serum with high performance and accuracy.

• 한국자기공명학회논문지
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• 제17권2호
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• pp.98-104
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• 2013

The ERETIC (Electronic REference To access In vivo Concentrations)2 method is a new qNMR experimental technique to measure analytes based on the signal of the reference compound without additional hardware equipment. In this study, ERETIC2 method was validated, and we sought to identify whether it would be possible to apply this method to a specific compound analysis of metabolites in plant. The $90^{\circ}$ pulse value (P1) and spin-lattice relaxation time ($T_1$) of each compound were measured for ERETIC2. The $9^1H$ of 3-(trimethylsilyl) propionic-2,2,3,3-$d_4$ acid (TSP) was used as a reference peak for ERETIC 2, and then, a suitable solvent and pulse sequence for each compound were selected. Under the NOESY-presat sequence, the relative accuracy error for quantitative analyses of primary metabolites was within the range of 5%, with the exception of glucose, which showed ${\geq}$ 55% error due to saturation. It showed excellent results for the quantification of glucose by using a $30^{\circ}$ pulse sequence, which did not suppress the water peak. In addition, the quantitative accuracy for secondary metabolites was extremely accurate, with an error ${\leq}$5% when considering the purity of the standard sample. The ERETIC2 method showed outstanding linearity, precision, and accuracy.

• 한국동물위생학회지
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• 제45권3호
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• pp.243-248
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• 2022

The HPLC conditions for analysis of ivermectin in solutions dosage forms of commercial anthelmintics are different for each product. The purpose of this study was to establish a standardized chromatographic method for the quantification of ivermectin in solution. The separation was achieved on Waters Xbridge C18 column (4.6×150 nm, 5 ㎛) using different kinds of mobile phase composed of water/methanol/acetonitrile (15/34/51, v/v and 19.5/27.5/53, v/v), with UV detection at wavelengths 245 nm and 254 nm. A total of five commercial ivermectin in solution samples were analyzed. In this study, the optimal chromatographic conditions for analysis of ivermectin in solution were mobile phase of water/methanol/acetonitrile (15/34/51, v/v) at a flow rate of 1.0 mL/min and a detection wavelength of 245 nm using a Waters Xbridge C18 column (4.6×250 nm, 5 ㎛) at a column temperature of 25℃. The linearity was observed in the concentration range of 50~150 ㎍/mL, with a correlation coefficient, r²= 0.99999. The limit of detection and the limit of quantification were 0.88 and 2.68 ㎍/mL, respectively. The accuracy (% recovery) was found to be 98.9 to 100.3%. Intra-day and Intermediate precisions with relative standard deviations were less than 1.0%. The content of ivermectin for five market samples ranged 91.2~102.7%. The proposed method was also found to be robust, therefore, the method can be used for the routine analysis of ivermectin in solutions dosage forms.

• 한국식품과학회지
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• 제53권6호
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• pp.682-687
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• 2021

The purpose of this study was to validate a high-performance liquid chromatography (HPLC) method for the quantitative analysis of quercetin in various foods. The method was based on HPLC-UV (360 nm). The method was validated using candy, beverage, and sausage which were tested for specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy, and the measurement uncertainty was assessed. Matrix-matched calibration was also applied. The calibration curves (0.5-50 mg/L) showed good linearity (r²≥0.9998). LOD and LOQ ranged from 0.15 to 0.31 mg/kg and from 0.44 to 0.93 mg/kg, respectively. The average accuracy and precision at 0.5, 2.5, and 10 mg/kg ranged from 84.3 to 102.0% and 0.7 to 3.0 relative standard deviation (RSD%), respectively. This study confirmed the applicability of the proposed method by applying it to commercial products, such as teas and beverages. Thus, the proposed analytical method is suitable for quantifying quercetin in various foods.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1146-1156
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• 2021

Single-unit probabilistic safety assessment (SUPSA) has complex Boolean logic equations for accident sequences. Multi-unit probabilistic safety assessment (MUPSA) model is developed by revising and combining SUPSA models in order to reflect plant state combinations (PSCs). These PSCs represent combinations of core damage and non-core damage states of nuclear power plants (NPPs). Since all these Boolean logic equations have complemented gates (not gates), it is not easy to generate exact Boolean solutions. Delete-term approximation method (DTAM) has been widely applied for generating approximate minimal cut sets (MCSs) from the complex Boolean logic equations with complemented gates. By applying DTAM, approximate conditional core damage probability (CCDP) has been calculated in SUPSA and MUPSA. It was found that CCDP calculated by DTAM was overestimated when complemented gates have non-rare events. Especially, the CCDP overestimation drastically increases if seismic SUPSA or MUPSA has complemented gates with many non-rare events. The objective of this study is to suggest a new quantification method named probability subtraction method (PSM) that replaces DTAM. The PSM calculates accurate CCDP even when SUPSA or MUPSA has complemented gates with many non-rare events. In this paper, the PSM is explained, and the accuracy of the PSM is validated by its applications to a few MUPSAs.

• 분석과학
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• 제34권4호
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• pp.153-159
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• 2021

In this study, we describe the development of a new high-performance liquid chromatography (HPLC) method for the simultaneous analysis of six bioactive compounds (including gallic acid, epicatechin 3-gallate, quercitrin, afzelin, quercetin, and kaempferol) from Orostachys japonicus. The extraction method was investigated and optimization of the extraction time (min), solvent composition (%), and solvent to material ratio were conducted. As a result, 30 min extraction with 50% methanol and 40:1 mL/g of solvent: material ratio achieved the highest extraction efficiency with a yield of 3.32 mg/g. Furthermore, the developed HPLC method was validated and the correlation coefficient (R) values were within the satisfactory range of 0.9995-0.9999 over the linearity range of 1.53-417 ㎍/mL. The limit of detection and limit of quantification for the six active components were between 0.03-0.08 ㎍/mL and 0.08-0.26 ㎍/mL, respectively. With these newly optimized and developed methods, four batches of O. japonicus were analyzed to confirm the high extraction efficiency of the method and the feasibility of an application.

• 한국한의학연구원논문집
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• 제11권2호
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• pp.167-178
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• 2005

As a part of the quality control of herbal prescriptions which has been used for diabetes and related diseases, a reversed-phase liquid chromatographic method was developed for the simultaneous quantification of the three marker compounds, puerarin (Puerariae Radix), glycyrrhizin (Glycyrrhizae Radix), schizandrin (Schizandrae Fructus) in Oc Chun San. The HPLC analysis method was validated for parameters such as linearity, Limits of Detection(LOD), quantification(LOQ), repeatability, stability and recovery.

• 한국안전학회지
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• 제30권3호
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• pp.100-106
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• 2015

A module or independent subtree is a part of a fault tree whose child gates or basic events are not repeated in the remaining part of the fault tree. Modules are necessarily employed in order to reduce the computational costs of fault tree quantification. This quantification generates fault tree solutions such as minimal cut sets, minimal path sets, or binary decision diagrams (BDDs), and then, calculates top event probability and importance measures. This paper presents a new linear time algorithm to detect modules of large fault trees. It is shown through benchmark tests that the new method proposed in this study can very quickly detect the modules of a huge fault tree. It is recommended that this method be implemented into fault tree solvers for efficient probabilistic safety assessment (PSA) of nuclear power plants.

• 생약학회지
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• 제47권2호
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• pp.192-196
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• 2016

The herb of Agastache rugosa (Lamiaceae) called Korean mint as a spice or Agastache Herba as a crude drug is known to contain highly fragrant volatile substances. This research aimed to establish the quantitative gas chromatography (GC) method on the essential oil of A. rugosa using the three standard compounds, estragole, methyleugenol, pulegone, and to find whether the essential oil has anti-Alzheimer's activity. The GC quantification method was established by determining the linearity of calibration curve ($R^2$), linear range, and both limit-of-detection (LOD) and limit-of-quantification (LOQ). The $IC_{50}$ of the essential oil on the activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were determined to be $69.06{\pm}0.26$ and $76.71{\pm}0.58{\mu}g/ml$, respectively.