• Clinical and Experimental Reproductive Medicine
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• v.43 no.2
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• pp.112-118
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• 2016

Objective: Ovarian reserve tests are commonly used to predict ovarian response in infertile patients undergoing ovarian stimulation. Although serum markers such as basal follicle-stimulating hormone (FSH) or random $anti-M{\ddot{u}}llerian$ hormone (AMH) level and ultrasonographic markers (antral follicle count, AFC) are good predictors, no single test has proven to be the best predictor. In this study, we developed appropriate equations and novel nomograms to predict the number of oocytes that will be retrieved using patients' age, serum levels of basal FSH and AMH, and AFC. Methods: We analyzed a database containing clinical and laboratory information of 141 stimulated in vitro fertilization (IVF) cycles performed at a university-based hospital between September 2009 and December 2013. We used generalized linear models for prediction of the number of oocytes. Results: Age, basal serum FSH level, serum AMH level, and AFC were significantly related to the number of oocytes retrieved according to the univariate and multivariate analyses. The equations that predicted the number of oocytes retrieved (log scale) were as follows: model (1) $3.21-0.036{\times}(age)+0.089{\times}(AMH)$, model (2) $3.422-0.03{\times}(age)-0.049{\times}(FSH)+0.08{\times}(AMH)$, model (3) $2.32-0.017{\times}(age)+0.039{\times}(AMH)+0.03{\times}(AFC)$, model (4) $2.584-0.015{\times}(age)-0.035{\times}(FSH)+0.038{\times}(AMH)+0.026{\times}(AFC)$. model 4 showed the best performance. On the basis of these variables, we developed nomograms to predict the number of oocytes that can be retrieved. Conclusion: Our nomograms helped predict the number of oocytes retrieved in stimulated IVF cycles.

• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.27-32
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• 1986

Electrical conductivities of NiO-$Y_2O_3$ systems containing 0.8, 1.6, and 3.2 mol% NiO have been measured in the temperature range of 400 to 1100$^{\circ}$C at $PO_2$'s of 1 ${\times}10^{-5}$ to 2 ${\times}10^{-1}$ atm. Plots of $log\sigma$ vs 1/T at constant $PO_2$'s are found to be linear with an inflection at temperature around 650$^{\circ}$C. The slopes are steeper in the high temperature region above 650$^{\circ}$C than in the low temperature region below 650$^{\circ}$C. The average activation energies are 41.8kcal/mol in the high temperature region and 12.5kcal/mol in the low temperature region. $PO_2$'s dependence value, 1/n, is 1/5.1~1/5.4 in the high temperature region and 1/5.9~1/6.2 in the low temperature region. The NiO-$Y_2O_3$ systems are found to be an electronic p-type semiconductor. The predominant defects in the systems are believed to be triply ionized yttrium vacancy in the high temperature region and doubly ionized oxygen interstitial in the low temperature region. Ionic contribution to the total conductivity is found from ${\sigma}^{\propto}PO_2$ in the temperatures below 650$^{\circ}$C.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.640-652
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• 1994

This work is undertaken to determine alcohol homologues so-called fusel oil that may be present in the Korean folk sojues (distilled liquor) made from grains and to describe sample preparation and analytical method by GC-FID-MS. Solid phase extraction method for sample preparation by using porous styrene divinyl benzene polymer (Porapak Q) was compared with steam distillation and solvent extraction method. Retention behaviors of homologous series of alcohols were also studied. Log values of retention time, molecular weight, boiling point, and capacity factor of alcohols showed linear correlations to the carbon number of an alcohol, to the oven temperature, and to the dielectric constant. Components such as methyl alcohol, n-propyl alcohol, isobutyl alcohol, isopentyl alcohol, and phenethyl alcohol have been identified. The more amount of isopentyl alcohol than other alcohols are contained in the Korean folk sojues, while that of n-propyl alcohol are contained in Chinese kaoliangchiew. Degree of similarity or dissimilarity and classification of the individual samples were discussed using multivariate statistical analysis(principal components analysis) based on GC data.

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.1026-1032
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• 1996

The effects of steeping temperature $(7^{\circ},\;15^{\circ},\;20^{\circ}\;and\;30^{\circ}C)$ and steeping time $(2{\sim}14\;hr)$ on the physicochemical properties of milled rice (variety; Chucheongbyeo) were investigated. The pH of the steep water decreased as the steeping time increased, which was more pronounced at higher steeping temperature. The solid loss was about 4.0% during steeping. The contents of protein, fat and ash decreased during steeping, which was greater at elevated temperature. The lightness of rice was slightly increased, and the yellowness was decreased upon steeping. The water-binding capacity of rice was increased during steeping at above $15^{\circ}C$. The slight increase of the swelling power of rice at $80^{\circ}C$ was observed upon steeping. The maximum wavelengh for the rice flour-iodine complex was moved to a higher wavelengh, but X-ray diffraction patterns remained constant regardless the steeping conditions. The pasting properties of rice flour (10%) by amylograph indicated that the peak viscosity increased as the steeping time was increased at all steeping temperatures. The steeping resulted in the greater breakdown and the 1ower setback. The log peak viscosity showed a linear relationship with the steeping time. The activation energy and $Q_{10}$ value for the visciosity increase rate was 2, 320 cal/mole and 1.14, respectively.

• Journal of the Korean Chemical Society
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• v.29 no.6
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• pp.608-614
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• 1985

Electrical conductivities of $ZrO_2-Sm_2O_3$ systems containing 10, 20, 30, 40, and 50 mol% of $ZrO_2$ have been measured as a function of temperature and of oxygen partial pressure at temperature from 500 to 1000${\circ}C$ and oxygen partial pressures from 1 ${\times}10^{-5}to 1{\times}10^{-1}$ atm. Plots of log conductivity vs. 1/T are found to be linear with an inflection point at around 650$^{\circ}C$ and the temperature dependence of conductivity shows two different defect structures. The conductivities are increased with increasing pressure, slowing a p-type character. The electrical conductivity dependences on $Po_2$ are found to be ${\sigma}{\propto}Po_2^{1/5.3}$ at 650∼1000$^{\circ}C$ and ${\sigma}{\propto}Po_2^{1/6}$ at 500∼650$^{\circ}C$, respectively, The defect structures are Oi" at 650-1000$^{\circ}C$ and $Vs_m$"' at 500-650$^{\circ}C$. The electron hole is main carrier type, however ionic contribution is found at low temperature portion. Ionic contributions increased with the increasing amount of $ZrO_2$ dopant. In 60mol% $ZrO_2-Sm_2O_3$ system, the conductivity is increased with decreasing oxygen pressure.

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.105-111
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• 1993

The stability constants for lanthanides complexes with optically active L-proline (1 : 1) were determined in aqueous solution in the ionic medium of 0.1 M $NaClO_4$ at 25$^{\circ}C$ using a pH titration method. The results show called "gadolinium break" between lighter and heavier lanthanides. The linear relation between the stability constant (log$\beta$1) and the pKa values of ligands indicates that L-proline acts as a bidentate ligand in the complexation. The thermodynamic parameters (${\Delta}H$ and ${\Delta}S$) were also determined using an enthalpy titration method at the same condition. The positive endothermic enthalpy change and positive entropy change clearly indicate that the driving force for the complexation is an entropy effect. The comparison of the thermodynamic parameters of L-proline complexes with anthranilate complexes supports the conclusion that the heterocyclic nitrogen atom and carboxylate of L-proline are involved in the chleate formation. The enthalpy values for L-proline are more positive than the ones for anthranilate complex. The difference in enthalpy change for the complex formation between L-proline complex and anthranilate complex is explained in terms of the basicity of the nitrogen donor atom in the ligand. The relatively large entropy change may be described by the extra dehydration related to the rigidity of L-proline ring.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.5
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• pp.23-30
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• 2000

To compensate the nonlinearity of electroabsorption modulator(EAM) resulting from its near exponential transfer function, a semiconductor optical amplifier(SOA) that has a log transfer function is used. Since the transfer function of SOA is inverse to that of EAM, the intermodulation distortion(IMD) of EAM can be reduced by cascading SOA to EAM. Also, the RF gain can be increased by the optical gain of SOA. For these reasons, spurious free dynamic range(SFDR) of EAM is enhanced by connecting SOA to EAM in series and operating in gain salutation region. To improve the nonlinearity compensation of EAM, the increased gain of SOA is required and the slope of gain saturation, the ratio of gain to input SOA power, needs to be steep. However, signal spontaneous beat noise that is the dominant system noise increases in proportion to the gain such that the SFDR of EAM is reduced. The higher the gain of SOA is, the more ASE is increased. Thus the noise level of system is increased and the following SFDR of EAM is decreased. The slope of gain saturation region and ASE of have trade-off relation and the optimization is achieved at 8㏈ optical gain. 9㏈ enhancement of SFDR of EAM is obtained. This scheme is easy to embody the linear EAM and the integration with three components (DFB-LD, EAM and SOA) offers many merits, such as low insertion loss, low chirping and low polarization sensitivity.

• Journal of the Korean Data and Information Science Society
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• v.25 no.5
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• pp.1057-1067
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• 2014

Many genetic variants have been identified to be associated with complex diseases such as hypertension, diabetes and cancers throughout genome-wide association studies (GWAS). However, there still exist a serious missing heritability problem since the proportion explained by genetic variants from GWAS is very weak less than 10~15%. Gene-gene interaction study may be helpful to explain the missing heritability because most of complex disease mechanisms are involved with more than one single SNP, which include multiple SNPs or gene-gene interactions. This paper focuses on gene-gene interactions with the survival phenotype by extending the multifactor dimensionality reduction (MDR) method to the accelerated failure time (AFT) model. The standardized residual from AFT model is used as a residual score for classifying multiple geno-types into high and low risk groups and algorithm of MDR is implemented. We call this method AFT-MDR and compares the power of AFT-MDR with those of Surv-MDR and Cox-MDR in simulation studies. Also a real data for leukemia Korean patients is analyzed. It was found that the power of AFT-MDR is greater than that of Surv-MDR and is comparable with that of Cox-MDR, but is very sensitive to the censoring fraction.

• Journal of Korea Technology Innovation Society
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• v.11 no.2
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• pp.241-263
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• 2008

Within any income approach, a discount rate is used to convert some projected free cash flow to its presented value. In case of valuing companies, the most frequently used discount rate is the weighted average cost of capital(WACC) at the aggregate level. But technology valuation is different to discounting aggregate corporate cash flow since it is concerned about individual Intellectual property. Therefore, blindly applying standard discount rate such as WACC in technology valuation is unlikely to lead to the right result. The primary focus of this paper is to establish the structure of discount rate for technology valuation and to suggest the method of estimation. To determine an appropriate discount rate for technology valuation, the level of technology risk, market risk and competitive risk should be included in the structure of discount rate. This paper suggests the build-up model which consists of three components as a expansion of the CAPM. It includes (1) a risk-free rate of return, (2) general market risk premium and beta and (3) intellectual property risk premium related to technology risk and specific target market risk. However, there is no specific check list for examining the intellectual property risk until now and no specific method for quantifying its risk into risk premium. This paper developed the 10 element to determine the level of the intellectual property risk and applied estimation function such as linear function, natural log function and exponential function to transform the level of risk into risk premium. The limitation of this paper is that the range of intellectual property risk premium is inferred based on the information of foreign and domestic valuation agency. Finally, this paper explored the development of an intellectual property discount rate for technology valuation and presented the method in order to quantify the intellectual property risk premium.

• The Korean Journal of Applied Statistics
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• v.6 no.2
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• pp.201-215
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• 1993

The health status of workers in a foundry was analyzed in a study which consisted of evaluations of respiratory health together with environmental measurements. The results from environmental measurements showed values exceeding permissible exposure limits. A t-test was done with log transformed and untransformed data to examine the statistical significance for the noncompliance with exposure standards. For the analysis of categorical health outcomes, $\chi$-square test with 2 $\times$ 2 tables and logistic regression analysis were employed. For continuous variables, multiple linear regression was done against assessed risk factors. Pros and cons of different parameters in the compliance (or noncompliance) testing were presented. Respiratory function did not show any relation with occupational exposures, which may be due to the healthy worker effects. Strategies for controlling time dependent covariates were discussed in relation to the healthy worker effect. The scope of statistical analysis in occupational health studies is still limited in Korea without a suitable external comparison group such as credible vital statistics for the whole nation. Internal comparisons between different exposure status often result in unstable estimates of effect, and proportional morbidity study is discussed as an alternative potential research tool.