• Bulletin of the Korean Chemical Society
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• 제15권1호
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• pp.74-77
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• 1994

Rare earth elements (REE) were individual separated by applying the gradient elution via HPLC using ${\alpha}-hydroxyisobutyric$ acid (HIBA) as an eluent. However, the overlap of Y and Dy peaks was too severe to obtain the resolution of these two peaks. The target transformation factor analysis (TTFA) was applied to resolve the elution peaks of Y and Dy. [A]$_{raw}$ formed from the absorbances of mixed solution was factor analyzed. The abstract factor analysis(AFA) was used to determine the number of components that contributed to the poorly resolved peaks. The error theory in the AFA showed that the number of components was 2. The test vectors which correspond to pure component were selected from the standard solutions of Y and Dy. TTFA was accomplished by target testing. The results showed that the resolution of two peaks as well as the determination of Y and Dy were possible by the factor analysis.

• Bulletin of the Korean Chemical Society
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• 제14권6호
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• pp.692-696
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• 1993

Prediction of retention times in transition metal-mandelate and transition metal-tartrate complex systems were studied on the cation exchanger. Plots of k' vs [mandelate] and k' vs [tartrate] were obtained under the condition of a constant competing cation concentration. The equation to predict the retention time of transition metal ion was derived from the ion exchange equilibria. Individual capacity factors (${k_1}',\;{k_2}'$) and stability constants ($K_1,\;K_2$) of the complexes were calculated from the non-linear least square method. Good resolution of the transition metals was predicted by the stepwise equation in the gradient method. The values of retention times from the calculation and the experiment agreed well each other.

• Mycobiology
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• 제40권2호
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• pp.138-141
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• 2012

We measured physiological functionalities, including antihypertensive angiotensin I-converting enzyme inhibitory activity and immun-stimulating ${\beta}$-glucan content for sixty kinds of Makgeolli that is commercially available from the market. As a result, we selected R-12 commercial raw Makgeolli, with a high content of immuno-stimulating ${\beta}$-glucan, and R-14 commercial raw Makgeolli, exhibiting high antihypertensive activity. Due to the similarities in their overall physicochemical properties and raw materials used for fermentation, we compared the microbial flora in order to investigate the reason for the differences in their functionalities. Nested PCR and denaturing gradient gel electrophoresis for yeasts and bacteria were performed for analysis of microbial diversity of two different kinds of Makgeolli (i.e., R-12, R-14), which showed immuno-stimulating ${\beta}$-glucan content and exhibited a very high level of antihypertensive activity, respectively. Analysis of the 18S rDNA amplicon revealed a major presence of the yeast strain Pichia burtonii in every Makgeolli sample. Analysis of the 16S rDNA amplicon revealed a predominance of lactic acid bacteria, and the most frequent lactic acid bacteria were Lactobacillus ingluviei, L. fermentum, and L. harbinensis, and Lactobacillus sp. Among these, L. harbinensis was detected only in R-12 and L. ingluviei was found only in R-14. Different functionalities from the individual commercially available Makgeolli may be attributed to actions of different microbial flora during fermentation.

• 터널과지하공간
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• 제20권1호
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• pp.15-27
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• 2010

국토의 약 70%가 산악지형인 우리나라의 지형적 특성상 각종 건설공사에 따른 대절토 사면의 형성으로 인해 낙석의 위험성이 급증하고 있다. 특히 해마다 반복되는 집중호우 시의 사면 붕괴는 대규모 낙석을 동반하면서 막대한 인적, 물적 피해를 초래하고 있다. 이러한 문제점들을 해결하기 위해 많은 현장조사연구 및 기초연구들이 수행되고 있으나 이들 연구의 대부분은 낙석이 발생할 경우의 보강 및 낙석 위험도 분석 등에 국한되고 있어, 근본적인 낙석의 거동에 관한 검토 및 분석은 미진한 실정이다. 따라서 본 연구에서는 수치해석적 기법을 이용하여 사면의 외적 요소에 따른 낙석의 거동 특성을 규명하였으며, 이를 위해 개별요소법의 하나인 PFC2D가 이용되었다. 사면의 외적 요소로 사면의 표면상태, 구배, 소단 개수, 소단 구배 및 낙석의 크기에 대한 소단의 너비의 비 등이 검토되었으며, 이들 요소에 대한 다양한 변화를 통해 낙석의 거동 메커니즘이 수치해석적으로 분석되었다.

• 한국의류학회지
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• 제38권4호
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• pp.427-439
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• 2014

This study identifies the foot side shapes of elderly men by classifying foot types according to 3D foot shapes and analyzing individual characteristics. The subjects were 284 elderly men over 60 years of age who lived in Gwangju and did not have foot related diseases. They were measured with a scanner (Nexcan$^{(R)}$ of K&I Technology) to obtain three dimensional feet shapes. Anthropometric measuring items consisted of 28 items estimated on the right foot of each subject. 3D scan data were analyzed by various statistical methods such as factor analysis, ANOVA and cluster analysis using the statistical program SPSS 19.0. A total of 7 factors were extracted through a factor analysis and these factors represent 77.56% of total variance. The 8 factors were: inside height and side gradient, ankle thickness, size from foot center to ankle, lateral malleolus height, forefoot height, instep and heel height and gradient. A total of 3 clusters (as foot type) were categorized using 7 factor scores by cluster analysis. Type 1 was classified as high forefoot and low midfoot compared to the length. Type 2 was classified as low forefoot and high midfoot, and type 3 was classified as low forefoot and low midfoot.

• 한국연소학회지
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• 제17권1호
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• pp.48-57
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• 2012

Laminar lifted propane coflow-jet flames diluted with nitrogen were experimentally investigated to determine heat-loss-related self-excitation regimes in the flame stability map and elucidate the individual flame characteristics. There exists a critical lift-off height over which flame-stabilizing effect becomes minor, thereby causing a normal heat-loss-induced self-excitation with O(0.01 Hz). Air-coflowing can suppress the normal heat-loss-induced self-excitation through increase of a Peclet number; meanwhile it can enhance the normal heat-lossinduced self-excitation through reducing fuel concentration gradient and thereby decreasing the reaction rate of trailing diffusion flame. Below the critical lift-off height. the effect of flame stabilization is superior, leading to a coflow-modulated heat-loss-induced self-excitation with O(0.001 Hz). Over the critical lift-off height, the effect of reducing fuel concentration gradient is pronounced, so that the normal heat-loss-induced self-excitation is restored. A newly found prompt self-excitation, observed prior to a heat-loss-induced flame blowout, is discussed. Heat-loss-related self-excitations, obtained laminar lifted propane coflow-jet flames diluted with nitrogen, were characterized by the functional dependency of Strouhal number on related parameters. The critical lift-off height was also reasonably characterized by Peclet number and fuel mole fraction.

• Molecules and Cells
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• 제25권2호
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• pp.265-271
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• 2008

Single nucleotide polymorphisms (SNPs) are the most common form of human genetic variation. Non-synonymous SNPs (nsSNPs) change an amino acid. Organic anion transporters (OATs) play an important role in eliminating or reabsorbing endogenous and exogenous organic anionic compounds. Among OATs, hOAT4 mediates high affinity transport of estrone sulfate and dehydroepiandrosterone sulfate. The rapid bone loss that occurs in post-menopausal women is mainly due to a net decrease of estrogen. In the present study we searched for SNPs within the exon regions of hOAT4 in Korean women osteoporosis patients. Fifty healthy subjects and 50 subjects with osteoporosis were screened for genetic polymorphism in the coding region of SLC22A11 (hOAT4) using GC-clamp PCR and denaturing gradient gel electrophoresis (DGGE). We found three SNPs in the hOAT4 gene. Two were in the osteoporosis group (C483A and G832A) and one in the normal group (C847T). One of the SNPs, G832A, is an nsSNP that changes the $278^{th}$ amino acid from glutamic acid to lysine (E278K). Uptake of [$3^H$] estrone sulfate by oocytes injected with the hOAT4 E278K mutant was reduced compared with wild-type hOAT4. Km values for wild type and E278K were $0.7{\mu}M$ and $1.2{\mu}M$, and Vmax values were 1.8 and 0.47 pmol/oocyte/h, respectively. The present study demonstrates that hOAT4 variants can causing inter-individual variation in anionic drug uptake and, therefore, could be used as markers for certain diseases including osteoporosis.

• 대한화학회지
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• 제34권6호
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• pp.582-592
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• 1990

양이온 교환체 (LC-18 coated with $C_{20}H_{41}SO_4^-$)에서 희토류원소-$\alpha$HiBA 착물계의 머무름 거동을 연구하였다. [Na$^+$] 및 [$\alpha$-HiBA]의 등용매 또는 기울기 용리에 따른 희토류원소의 머무름을 나타내는 관계식을 이온 교환 평형식으로부터 유도하였다. [$Na+$] 및 [$\alpha$-HiBA]의 등용매 용리에 따른 크기성질(k')의 관계인 log k' vs log [$Na^+$] 및 log k' vs log [$\alpha$-HiBA]의 직선의 기울기 값에 대한 실험값과 계산값을 비교한 결과 서로 일치하였다. 위의 관계식으로부터 비선형 최소자승법으로 각 개별 착물들의 크기성질($k'_{Ln}^{3+}, k'_{LnL}^{2+}, k'{LnL2+}) 및 착물의 안정도 상수(${\beta}_1$, ${\beta}_2$, ${\beta}_3$)를 각각 구하였다. 희토류원소들의 크기성질(k')에 대한 실험값과 계산값의 상관계수가 0.9996보다 좋은 결과를 나타내었다.

• The Korean Journal of Physiology and Pharmacology
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• 제19권4호
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• pp.319-325
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• 2015

Among solute carrier proteins, the organic anion transporters (OATs) play an important role for the elimination or reabsorption of endogenous and exogenous negatively charged anionic compounds. Among OATs, SLC22A9 (hOAT7) transports estrone sulfate with high affinity. The net decrease of estrogen, especially in post-menopausal women induces rapid bone loss. The present study was performed to search the SNP within exon regions of SLC22A9 in Korean females with osteoporosis. Fifty healthy controls and 50 osteoporosis patients were screened for the genetic polymorphism in the coding region of SLC22A9 using GC-clamped PCR and denaturing gradient gel electrophoresis (DGGE). Six SNPs were found on the SLC22A9 gene from Korean women with/without osteoporosis. The SNPs were located as follows: two SNPs in the osteoporosis group (A645G and T1277C), three SNPs in the control group (G1449T, C1467T and C1487T) and one SNP in both the osteoporosis and control groups (G767A). The G767A, T1277C and C1487T SNPs result in an amino acid substitution, from synonymous vs nonsynonymous substitution arginine to glutamine (R256Q), phenylalanine to serine (F426S) and proline to leucine (P496L), respectively. The Km values and Vmax of the wild type, R256Q, P496L and F426S were 8.84, 8.87, 9.83 and $12.74{\mu}M$, and 1.97, 1.96, 2.06 and 1.55 pmol/oocyte/h, respectively. The present study demonstrates that the SLC22A9 variant F426S is causing inter-individual variation that is leading to the differences in transport of the steroid sulfate conjugate (estrone sulfate) and, therefore this could be used as a marker for certain disease including osteoporosis.

• 한국정보통신학회논문지
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• 제25권2호
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• pp.171-177
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• 2021

최근 머신러닝의 발전에 따라 일상생활과 산업에서 기술을 적용하는 사례들이 많아지고 있다. 금융 데이터와 머신러닝 기법을 활용한 연구 또한 활발하게 이루어지고 있다. 본 논문은 이러한 동향에 따라 상점 매출 데이터에 머신러닝 기법을 접목해 매출 예측 모델을 구축, 핀테크 산업에서의 활용 방안을 제시한다. 다양한 결측치 처리 기법을 적용하고 그래디언트 부스팅 기반의 머신러닝 기법인 XGBoost, LightGBM, CatBoost를 사용하여 각 모델의 상점 매출예측 성능을 비교한다. 연구 결과, 단일대체법 중 중앙값 대체법을 사용한 데이터셋에 XGBoost를 활용해 예측을 진행한 모델의 성능이 가장 우수했다. 연구를 통해 얻은 모델을 이용하여 상점의 매출 예측을 진행함으로서 핀테크 기업의 고객 상점들은 대출금을 상환하기 전 금융 보조를 받는 근거로, 핀테크 기업은 상환 가능성이 높은 우수 상점에 금융 상품을 제공하는 등 기업과 고객 모두에게 긍정적인 방향으로 활용할 수 있다.