• 한국지반공학회논문집
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• 제25권7호
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• pp.55-64
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• 2009

본 연구에서는 실제 현장조건을 고려하여 토목섬유의 화학저항성을 측정하기 위한 개선된 시험방법이 제안되었다. 이를 위하여 시공조건에 가장 근접한 시험법을 규격화하기 위한 인덱스 및 성능시험이 실시되었으며, Arrhenius 식에 의한 가속모델을 적용하여 실험 데이터를 해석하였다. 전반적인 실험 결과를 분석, 비교하여 현장 시공조건에 부합한 개선된 토목섬유의 화학저항성 시험방법을 확립하고 그 가능성을 제시하였다.

• Journal of Digestive Cancer Research
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• 제10권2호
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• pp.82-91
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• 2022

Gastrointestinal cancer accounts for one-third of the overall cancer occurrence worldwide. Pancreatic ductal adenocarcinoma (PDAC) is a type of gastrointestinal cancer that is known to be one of the most fatal among all cancer types, with a 5-year survival rate of less than 8%. Chemotherapy combined with surgical resection is its probable curative option. However, surgery is accessible for only 10-15% of patients diagnosed with PDAC. Organoids show self-organizing capacities and resemble the original tissue in terms of morphology and function. Organoids can also be cultured with high effectiveness from tumor tissues derived from each patient, making them an extremely fitting model for translational uses and improving personalized cancer medicine. Enhancing drug screening platforms is necessary to apply personalized medicinebased organoids in clinical settings.

• Korean Chemical Engineering Research
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• 제62권1호
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• pp.53-69
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• 2024

The solubility of Cloxacillin sodium in ethanol, 1-propanol, isopropanol, and acetone solutions was measured at different temperatures. The melting property was also tested by using a differential scanning calorimeter (DSC). Then, the solubility data were fitted using Apelblat equation and λh equation, respectively. The Wilson model and NRTL model were not utilized to correlate the test data, since Cloxacillin sodium will decompose directly after melting. For comparison purposes, the four empirical models, i.e., Apelblat equation, λh equation, Wilson model and NRTL Model, were evaluated by using 1155 solubility curves of 103 solutes tested under different monosolvents and temperatures. The comparison results indicate that the Apelblat equation is superior to the others. Furthermore, a new method (named the calculation method) for determining the Apelblat equation using only three data points was proposed to solve the problem that there may not be enough solute in the determination of solubility. The log-logistic distribution function was used to further capture the trend of the correlation and to make better quantitative comparison between predicted data and the experimental ones for the Apelblat equation determined by different methods (fitting method or calculation method). It is found that the proposed calculation method not only greatly reduces the number of test data points, but also has satisfactory prediction accuracy.

• Wind and Structures
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• 제38권4호
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• pp.309-323
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• 2024

The gust factor and turbulence intensity are two crucial parameters that characterize the properties of turbulence. In tropical cyclones (TCs), these parameters exhibit significant variability, yet there is a lack of established formulas to account for their probabilistic characteristics with consideration of their inherent connection. On this condition, a probabilistic analysis of gust factors and turbulence intensities of TCs is conducted based on fourteen sets of wind data collected at the Sutong Cable-stayed Bridge site. Initially, the turbulence intensities and gust factors of recorded data are computed, followed by an analysis of their probability densities across different ranges categorized by mean wind speed. The Gaussian, lognormal, and generalized extreme value (GEV) distributions are employed to fit the measured probability densities, with subsequent evaluation of their effectiveness. The Gumbel distribution, which is a specific instance of the GEV distribution, has been identified as an optimal choice for probabilistic characterizations of turbulence intensity and gust factor in TCs. The corresponding empirical models are then established through curve fitting. By utilizing the Gumbel distribution as a template, the nexus between the probability density functions of turbulence intensity and gust factor is built, leading to the development of a generalized probabilistic model that statistically describe turbulence intensity and gust factor in TCs. Finally, these empirical models are validated using measured data and compared with suggestions recommended by specifications.

• Membrane and Water Treatment
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• 제15권2호
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• pp.89-98
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• 2024

The ability of Zizyphus lotus stem powder (ZLSP) to remove Pb (II) and Cd (II) ions from an aqueous solution was evaluated. The present phenomenon of biosorption was revealed to depend on pH, biosorbent dosage, temperature, initial ionic concentration, time of contact and biosorbent's particle size. The sorption process was exothermic (∆H°<0), and showing a strong Pb(II)/Cd(II)-ZLSP affinity (∆S°>0). Gibbs free energy data (∆G°<0, and decreases as temperature increase) reveals that the process studied is characterized by its feasibility and spontaneous nature. The best fits of the equilibrium data were obtained by the Temkin model and the Langmuir model. The maximum Pb(II)/Cd(II)-ZLSP biosorption capacities were 33.02 mg/g for Pb (II) and 20.73 mg/g for Cd (II). The pseudo-second order model was the most appropriate for fitting the kinetic data. The characterization of the biochemical groups essentially involved in the sorption phenomenon was made possible by FTIR spectral analysis. The capacity of ZLSP as an effective and ecofriendly biosorbent is confirmed through this study.

• Asian-Australasian Journal of Animal Sciences
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• 제28권10호
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• pp.1407-1418
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• 2015

A total of 32,817 test-day milk yield (TDMY) records of the first lactation of 4,056 Girolando cows daughters of 276 sires, collected from 118 herds between 2000 and 2011 were utilized to estimate the genetic parameters for TDMY via random regression models (RRM) using Legendre's polynomial functions whose orders varied from 3 to 5. In addition, nine measures of persistency in milk yield ($PS_i$) and the genetic trend of 305-day milk yield (305MY) were evaluated. The fit quality criteria used indicated RRM employing the Legendre's polynomial of orders 3 and 5 for fitting the genetic additive and permanent environment effects, respectively, as the best model. The heritability and genetic correlation for TDMY throughout the lactation, obtained with the best model, varied from 0.18 to 0.23 and from -0.03 to 1.00, respectively. The heritability and genetic correlation for persistency and 305MY varied from 0.10 to 0.33 and from -0.98 to 1.00, respectively. The use of $PS_7$ would be the most suitable option for the evaluation of Girolando cattle. The estimated breeding values for 305MY of sires and cows showed significant and positive genetic trends. Thus, the use of selection indices would be indicated in the genetic evaluation of Girolando cattle for both traits.

• 응용통계연구
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• 제24권2호
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• pp.269-278
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• 2011

스코어 변수의 민감도와 특이도와의 관계로 표현한 ROC 곡선을 더욱 정확한 진단을 위하여 분포함수와 공변량을 고려한 연구가 많이 진행되었다. 공변량을 고려하는 회귀분석 방법을 사용하였으며 이때 분포함수를 정규분포로 가정하거나 잔차의 분포함수를 추정하여 ROC 분석을 하였다. 본 연구는 분포함수가 주어지지 않으며 진단에 영향을 주는 공변량을 모르는 일반적인 상황에서 논의하였다. 확률변수인 스코어와 두 개의 보모집단으로 구성된 신용평가 자료에 적합한 분포함수를 추정하기 위하여 여러 개의 정규분포가 혼합된 정규혼합분포를 사용하여 ROC 분석을 한다. 고전적인 비모수적이고 경험적인 ROC 곡선에 적합한지를 파악하기 위하여 AUC 통계량을 사용하여 비교하며, 본 연구에서 제안한 정규혼합분포를 이용한 ROC 곡선이 다른 방법으로 구한 ROC 곡선보다 적합함을 보였다.

• 한국농공학회논문집
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• 제48권7호
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• pp.55-63
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• 2006

Bacterial transport models were evaluated in this study to determine the suitable model at describing bacterial transport in saturated column experiments. Four models used in the evaluation were: advective-dispersive equation (ADE) + equilibrium sorption/retardation (ER) + kinetic reversible sorption (KR) (Model I), ADE + two-site sorption (Model 2), ADE + ER + kinetic irreversible sorption (KI) (Model 3), ADE + KR + KI (Model 4). Firstly, analyses were performed with the first experimental data, showing that Model 4 is appropriate for describing bacterial transport. Even if Model 1 and 2 fit well to the observed data, they have a defect of not including the irreversible sorption, which is directly related to mass loss of bacteria. Model 3 can not properly describe the tailing observed in the data. However, further analysis with the second data indicates that Model 4 can not describe retardation of bacteria, even if the sorption-related parameters are varied. Therefore, Model 4 is modified by incorporating retardation factor into the model, resulting in the improved fitting to the data. It indicates that the transport model, into which retardation, kinetic reversible sorption, and kinetic irreversible sorption are incorporated, is suitable at describing bacterial transport in saturated column experiments. It is expected that the selected transport model could be applied to properly analyze the bacterial transport in saturated porous media.

• 정보처리학회논문지A
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• 제10A권4호
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• pp.285-294
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• 2003

클러스터 웹 서버에서 사용되는 요청 분배 기법에는 부하 균형 요청 분배 기법과 내용 기반 요청 분배 기법이 있다. 부하 균형 요청 분배 기법은 실제 서버들의 부하 균형을 목적으로 실제 서버를 선택하는 기법이다. 반면 내용 기반 요청 분배 기법은 캐쉬 친화적인 기법으로 요청 패킷의 내용에 따라서 실제 서버를 선택하게 된다. 이는 부하 균형보다는 각 실제 서버 내의 캐쉬 참조율을 높이는 것을 목적으로 한다. 하지만 현재 두 기법의 성능 비교에 관한 명확한 자료가 부족한 상태여서 본 논문에서는 두 기법에 관한 성능 평가 결과를 보이고자 한다. 이를 위해 우리는 리눅스 클러스터 웹 서버를 구현한 후 이 두 기법간의 성능을 비교, 분석한다. 이 비교/분석 결과를 활용할 경우 부하 상황에 따른 적절한 요청 분배 기법을 선택하는 데에 도움을 줄 수 있다는 것이 본 논문이 기여하는 바라 할 것이다.

• 재활복지공학회논문지
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• 제8권4호
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• pp.305-312
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• 2014

본 연구에서는 재활정도를 정량적으로 표현하기 위하여 정상 보행과 모의 비정상 보행 시 보행주기에 따른 근전도 패턴에 고차 곡선 맞춤을 적용하여 분석하였다. 보행 근전도 패턴에 적합한 다항식을 생성하였으며, 그 변수를 군집분석 하여 5개의 그룹으로 분류하였다. 정상패턴을 포함한 그룹을 기준으로 거리가 가까운 그룹을 나열하여 각 변수의 분포를 확인하였다. 진폭감소 패턴, 불규칙 패턴, 역상 패턴 순으로 정상 패턴에 유사하였으며, 분류된 그룹의 분포는 중첩되는 범위가 작아 변수 값을 이용한 그룹 분류가 가능하였다. 분류된 재활정도를 정량적으로 나타내기 위하여 각 계수항의 표준편차를 패턴별로 비교하였고, 정상에 가까울수록 큰 값을 가지는 것을 확인하였다. 역상 패턴의 경우는 편차 값은 크지만 부호가 음의 값을 가지므로 가장 작았다. 본 연구의 결과인 정량적인 재활정도의 표현은 보다 효율적인 재활방법 연구에 기여할 것으로 예상된다.