• Analytical Science and Technology
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• v.12 no.6
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• pp.528-533
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• 1999

The total iodine is determined in serum, fresh milk and feed additive by ICP-MS. The preparation involves only a 25-fold dilution with a diluent by direct nebulization in the plasma. The diluent composition is $NH_4OH$(0.5% v/v)+$CH_3OH$(5% v/v) and the abundance of iodine is measured at m/z=127. The calibration curve was linear over the ranges $0-100{\mu}g/L$ with $R^2=0.99$ for iodine. The detection limit of this method is $0.084{\mu}g/L$ for iodine. The relative error range of milk powder SRM in optimum condition is 2.30%-4.73%. The concentration ranges of iodine in the serum, fresh milk, feed additive were $12.4-40.2{\mu}g/L$, < 0.01-3.11 mg/L, < $10^{-7}-2.60g/kg$ respectively.

• Analytical Science and Technology
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• v.14 no.5
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• pp.410-415
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• 2001

An analytical method has been developed which determines lead in steel samples by inductively coupled plasma mass spectrometry (ICP-MS) with sample introduction by the hydride generation. The lead hydride is not stable and requires and oxidant for the oxidation into metastable Pb(IV) before reduction to $PbH_4$ with $NaBH_4$. A study was carried out to find and optimum lead hydride generation condition for a sample solution with more than $1000{\mu}g/mL$ Fe matrix. $K_2Cr_2O_7$ was found to work as an efficient oxidant when more than $10{\mu}g/mL$ Fe matrix was present. Lactic acid was used with the oxidant as a complexing agent of the metastable Pb(IV) to enhance sensitivity. Optimum concentrations of the sample acidity, oxidant and lactic acid were different depending on the matrix concentration. The isotope dilution method was employed for the quantitation of lead. The determined Pb concentrations of the NIST steel SRM 361 and 362 were in good agreement with the certified values within the uncertainty range.

• The Korean Journal of Financial Management
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• v.19 no.2
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• pp.233-251
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• 2002

본 연구는 우리나라를 대상으로 장단기 스프레드와 신용스프레드가 경기변동에 대해 어떠한 예측력을 갖고 있는가를 살펴보았다. 이를 위해 1991년부터 2001년까지를 분석기간으로 하여 Probit 분석을 통해 금리스프레드와 경기변동과의 시차 및 불황확률을 추정하여 평가해 보았으며, 인과관계 검정을 시도해 보았다. 우선 금리스프레드와 경기변동에 대한 불황확률을 알아보기 위해서 Probit 모형을 이용하여 불황확률을 추정하였다. 그 결과 장단기 금리스프레드 중에서는 5년 만기 1종 국민주택채권수익률-콜금리(HCS)는 3개월, 5년 만기 1종 국민주택채권수익률-1년 만기 금융채수익률(HGS)은 7개월, 5년 만기 1종 국민주택채권수익률-1년 만기 통안증권수익률(HMS)은 9개월의 시차를 보이는 경우가 Pseudo $R^2$ 값이 가장 높게 나타났지만 불황확률을 토대로 경기 호황과 불황 국면을 비교해 본 결과 HMS는 Pseudo $R^2$의 값도 상대적으로 높았을 뿐만 아니라 매우 높은 경기변동 예측력을 보여주었다. HCS와 HGS의 경우에는 IMF 체제 전후의 불황기와 그 이후에 도래한 호황기는 예측력이 높게 나타났으나 1990년대 초반에는 제대로 불황확률을 예측하지 못하는 것으로 나타났다. 또한 3년 만기 회사채수익률-5년 만기 국민주택채권수익률(CHS)와 3년 만기회사채수익률 -3년 만기 금융채수익률(CGS)로 나타낸 신용 스프레드에서는 유의적인 결과를 도출하지는 못하였다. 한편 인과관계에서도 HCS, HGS, HMS 등의 장단기 스프레드는 경기변동에 대하여 일방적 원인변수로 작용하는 것으로 나타나 선행결합관계를 보여주었으나 CHS, CGS 등의 신용스프레드는 경기변동과 어떠한 유의적인 결합관계도 보여주지 못하였다. 따라서 장단기 스프레드는 경기변동을 예측하는데 유용한 정보를 제공하지만 신용스프레드는 경기변동을 예측하는데 도움을 주지 못하는 것으로 나타났다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.147-155
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• 1993

An urban runoff model is proposed in this study, which is composed of a surface runoff model and a channel routing model. ILLUDAS is selected as the best fit model for the surface runoff computation, and the dynamic wave model using weighted four-point implicit finite difference scheme is used to perform the channel routing. The 3rd Seongbook bridge basin located in Seoul is selected as the test basin for the proposed model, and the rainfall-runoff data are collected to calibrate and verify the urban runoff model. The computed results by this model showed the fair accuracy when compared with the observed hydrographs. So the model proposed in this study could be used to compute the urban river flow as well as the outflow from the urban drainage area.

• Applied Biological Chemistry
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• v.14 no.3
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• pp.177-182
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• 1971

A new method for the measure of iron pools using 0.02M EDTA and $Na_2S_2O_4$ was tested on Akagare diseased and healthy rice leaf tissue 1) The proposed method could fraction iron into four fractions; ferrous iron($Fe^{++}$), ferric iron($Fe^{+++}$) precipitated iron(PFe) and bound iron(BFe) well indicating the physiological status of tissue. 2) The pattern of iron pools appears to be $Fe^{+++}>PFe>BFe>Fe^{++}$ in most physiologically favorable status of iron, $PFe>Fe^{+++}>BFe>Fe^{++}$ in favorable status, $BFe>Fe^{+++}>PFe>Fe^{++}$ in unfavorable status and $BFe>PFe>Fe^{+++}>Fe^{++}$ in toxic status. 3) The percentage of each fraction to total iron was less than 10 for $Fe^{++}$, 20 to 40 for $Fe^{+++}$ and PFe and 20 to 50 for BFe. 4) Ferrous iron was always higher in upper half leaf, the appearance of which is less healthier than lower half indicating that there is more active metabolic system in which ferrous iron is involved.

• Analytical Science and Technology
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• v.8 no.3
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• pp.221-227
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• 1995

The fiber optic fluorosensor that shows a specific selectivity for calcium ion is studied. This sensor employs protein Calmodulin(CaM) which forms a fluorescent chelate with $Ca^{2+}$. A dialysis membrane is used to entrap a fluorescein isothiocyanate-labeled CaM solution at the common end of a bifurcated fiber optic bundle. The sensing mechanism of this sensor is based on the shifts in the fluorescence spectrum of metal-calmodulin complexes which FCaM forms a chelate with $Ca^{2+}$. Upon binding with $Ca^{2+}$, CaM undergoes a conformational change which induces a change in the fluorescence of FCaM. This change in fluorescence signal which is measured by photomultiflier tube is related to the concentration of $Ca^{2+}$ for calibration curve. Detection limit for $Ca^{2+}$ and the interference effects by $Mg^{2+}$, $Eu^{3+}$ and $La^{3+}$ for this sensor are studied. Response time and life time for this fluorosensor are also investigated.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.123-123
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• 2018

가뭄은 홍수와 달리 진행속도가 비교적 느리기 때문에 초기에 감지한다면 피해를 최소화 할 수 있다. 국내에서는 가뭄전망을 위해 물리적 기반의 기상-수문연계해석 시스템을 구축하여 월 내지 계절전망을 수행하고 있다. 물리적 기반의 가뭄전망은 수치예보모델의 불확실성을 가지고 있으므로 예보 정확도 개선의 측면에서는 통계적 모델을 같이 활용하는 것이 바람직하다. 최근 국외에서는 통계적 방법인 AI (Artificial Intelligence) 기술을 사용하여 가뭄을 전망하는 연구가 활발히 진행 중이나, 아직까지 국내에서는 관련연구가 미흡한 실정이다. 이에 본 연구에서는 ANFIS (Adaptive Neuro-Fuzzy Inference System) 기반의 댐 유입량 예측 모델을 구축하고 SRI (Standardized Runoff Index)를 활용하여 수문학적 가뭄전망을 수행하였다. 대상유역은 국내 주요 다목적댐이 위치한 충주댐 유역과 소양강댐 유역을 선정하였다. 수문 및 기상자료는 국토 교통부 및 기상청의 관측 댐 유입량, 관측 강수량, 관측 기온 및 장기기상예보 자료를 사용하였다. ANFIS 모델 구축을 위한 훈련 및 보정기간과 검정기간은 각각 1987~2010년과 2011~2016년을 선정하였다. 수문학적 가뭄전망은 지속기간 3개월의 1개월 전망 SRI3를 활용하였으며, SRI3는 관측유입량과 예측유입량을 결합하여 산정하였다. 댐 예측유입량 및 수문학적 가뭄전망의 정확도 평가를 위해 상관계수, 평균제곱근오차를 활용하였다. 댐 예측유입량 평가 결과 예측값과 관측값의 상관계수가 높게 나타났으며, 평균제곱근오차는 낮아 예측성이 뛰어났다. SRI3의 경우 관측값과 예측값의 가뭄발생시기가 유사하여 가뭄을 적절하게 반영하는 것으로 나타났다. 본 연구의 결과는 통계적 기반의 수문학적 가뭄전망기법을 개발하였다는 측면에서 의의가 있으며, 향후 물리적 기반의 가뭄전망정보와 결합한다면 보다 실효성이 향상될 것으로 기대된다.

• Journal of Korea Water Resources Association
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• v.47 no.9
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• pp.753-766
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• 2014

The future mean sea level rise (MSLR) due to climate change in major harbors of Korean Peninsula has been estimated by some statistical methods in this article. Firstly, Mann-Kendall non-parametric trend test to find some trend in the observed long-term tidal data has been performed and also Bayesian change point analysis has been used also to detect the location of change points and their magnitude quantitatively. Especially, in this study, the results from Bayesian change point analysis have been applied to combine 4 future MSLR scenario projections with local MSLR data at 5 tidal gauges. This proposed procedure including Bayesian change point analysis results can improve the step for the determination of starting years of future MLSR scenario projections with 18.6-year lunar node tidal cycle and effectively consider local characteristics at each gauge. The final results by the proposed procedure in this study have shown that the future MSLR in Jeju region (Jeju tidal gauge) is in the largest increment and also the future MSLRs in Western region (Boryeong tidal gauge) and Southern region (Busan tidal gauge) are in the second largest one. Finally, it has been shown that the future MSLRs in Southern region (Yeosu tidal gauge) and Eastern region (Sokcho tidal gauge) seem to be in the relatively smallest growth among 5 gauges.

• Science of Emotion and Sensibility
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• v.24 no.2
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• pp.81-92
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• 2021

In this study, we investigated the effects of five EMS lumbar back pressure belts produced on an anatomical basis on lumbar spine stabilization. Five core muscles were selected, including the urinal, vertebral column, endotracheal, external abdominal, and large back muscles, and patterns were designed using a conductive fabric considering the appropriate muscle shape and pain-causing points. We experimented with four motions to examine the effects of different EMS abdominal compression belts on lumbar spine stabilization. Five healthy men in their 20s were selected. The selection conditions include no back pain history for the past three months, no restricted movements through pre-inspection, and the muscular strength of the body should belong to the normal grade. Using SLR, the sequence of experimental actions was chosen from the following but not limited to left-hand, body-hand, and back-line forces. Resting between movements lasted for 2 min, and the experiments were conducted after wearing the EMS abdominal pressure belt. Electrical stimulation was applied for 10 min to increase blood flow and muscle activation. The statistics of the experimental results were analyzed for specific differences by conducting the Wilcoxon and Friedman tests with nonparametric tests. The ranking results of each pattern were successfully assessed in the order of 5, 4, 3, 1, 2 for the five patterns, and we could identify slightly more significant results for experimental behavior associated with each muscle movement. Patterns produced based on anatomy showed differentiated effects when electric stimulation was applied to each muscle in different shapes, which could improve the stabilization of the lumbar spine in everyday life or training to the public. Based on these results, subsequent research would focus on developing smart healthcare clothing that is practical in daily life by employing different anatomical mechanisms, depending on the back pain, to utilize trunk-type tights.

• Journal of Venture Innovation
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• v.6 no.4
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• pp.153-170
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• 2023

Generative AI services, including ChatGPT, were becoming increasingly active. This study aimed to empirically analyze the factors that promoted and hindered the diffusion of such services from a consumer perspective. Accordingly, a research model was developed based on the Value-based Adoption Model (VAM) framework, addressing both benefit and sacrifice factors. Benefits identified included usefulness and enjoyment, while sacrifices were security and hallucination. The study analyzed how these factors affected the intention to use generative AI services. A survey was conducted among college students for empirical analysis, and 200 valid responses were analyzed. The analysis utilized structural equation modeling with AMOS 24. The empirical results showed that usefulness and enjoyment had a significant positive impact on perceived value, while security and hallucination had a significant negative impact. The order of influence on perceived value was usefulness, hallucination, security, and then enjoyment. Perceived value had a significant positive impact on usage intention. Moreover, perceived value was found to mediate the relationship between usefulness, enjoyment, security, hallucination, and the intention to use generative AI services. These findings expanded the research horizon academically by validating the effectiveness of generative AI services based on existing models and demonstrated the continued importance of usefulness in a practical context.