• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1492-1496
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• 2006

수공구조물의 설계에 있어 가중 중요한 변수 중에 하나가 확률 강우량이다. 우리나라의 경우 매개변수적인 지점빈도해석을 통해 확률 강우량을 산정하고 있으나, 최근 들어 지점별 관측자료의 부족으로 인한 지역빈도해석을 수행하여 확률강우량을 산정하고 있는 실정이다. Index Flood 기법이나 L-moment 기법과 같은 기존의 지역빈도해석은 여러 관측 지점에서 관측된 강우자료를 이용하여 매년최대 시간강우량 자료를 추출하여 동질성 분석을 통해 이질성이 없는 것으로 분석된 연최대 강우량을 빈도해석 하여 확률 강우량을 결정한다. 그러나 이와 같은 지역빈도해석은 매개변수적 지점빈도해석과 마찬가지로 적합도 검정에 통과한 다수의 분포형이 선정되는 경우에 어떤 분포형을 사용하느냐 하는 문제점이 발생할 수 있다. 그리고 선정된 여러 강우 관측 지점의 연최대 강우량 자료에 모두 동일한 확률 분포형을 이용하므로 선정된 확률 분포형이 모든 지점의 강우 자료와 적합하지 못할 가능성을 내포하고 있으며, 또한 수문자료가 여러가지 요인으로 인하여 복합분포(mixed distribution)형태를 가질 때, 매개변수적 해석방법으로는 다중 첨두를 갖는 확률밀도함수를 해석하는데는 여러 가지 어려움이 따른다. 따라서 이러한 매개변수적 확률분포형을 이용한 빈도해석의 문제점을 해결할 수 있는 비매개변수적 빈도해석이 하나의 대안으로 제시될 수 있다. 본 연구에서는 강우자료의 선별을 통해 신뢰성 있는 자료를 구축하고, 기존의 매개변수를 갖는 확률 분포형을 이용한 지역빈도해석을 적용하여 확률 강우량을 산정하였다. 그리고 동질성분석을 통해 선정된 강우자료에 대해 비매개변수적 지역빈도해석을 적용하여 확률 강우량을 산정하고 각각의 방법에 대한 빈도해석 결과를 비교하여 확률강우량 해석에 있어 하나의 대안을 제시하고자 한다.X>${\mu}_{max,A}$는 최대암모니아 섭취률을 이용하여 구한 결과 $0.65d^{-1}$로 나타났다.EX>$60%{\sim}87%$가 수심 10m 이내에 분포하였고, 녹조강과 남조강이 우점하는 하절기에는 5m 이내에 주로 분포하였다. 취수탑 지점의 수심이 연중 $25{\sim}35m$를 유지하는 H호의 경우 간헐식 폭기장치를 가동하는 기간은 물론 그 외 기간에도 취수구의 심도를 표층 10m 이하로 유지 할 경우 전체 조류 유입량을 60% 이상 저감할 수 있을 것으로 조사되었다.심볼 및 색채 디자인 등의 작업이 수반되어야 하며, 이들을 고려한 인터넷용 GIS기본도를 신규 제작한다. 상습침수지구와 관련된 각종 GIS데이타와 각 기관이 보유하고 있는 공공정보 가운데 공간정보와 연계되어야 하는 자료를 인터넷 GIS를 이용하여 효율적으로 관리하기 위해서는 단계별 구축전략이 필요하다. 따라서 본 논문에서는 인터넷 GIS를 이용하여 상습침수구역관련 정보를 검색, 처리 및 분석할 수 있는 상습침수 구역 종합정보화 시스템을 구축토록 하였다.N, 항목에서 보 상류가 높게 나타났으나, 철거되지 않은 검전보나 안양대교보에 비해 그 차이가 크지 않은 것으로 나타났다.의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.549-557
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• 2013

An flood inundation map is able to convey spatial distribution of inundation to a decision maker for flood risk management. A roughness coefficient with unclear values and a discharge obtained from the stage-discharge rating equation are key sources of uncertainty in flood inundation mapping by using a hydraulic model. Also, the uncertainty analysis needs an observation for the flood inundation, and satellite images is useful to obtain spatial distribution of flood. Accordingly, the objective of this study is to quantify uncertainty arising roughness and discharge in flood inundation mapping by using a hydraulic model and a satellite image. To perform this, flood inundations were simulated by HEC-RAS and terrain analysis, and ISODATA (Iterative Self-Organizing Data Analysis) was used to classify waterbody from Landsat 5TM imagery. The classified waterbody was used as an observation to calculate F-statistic (likelihood measure) in GLUE (Generalized Likelihood Uncertainty Estimation). The results from GLUE show that flood inundation areas are 74.59 $km^2$ for lower 5 % uncertainty bound and 151.95 $km^2$ for upper 95% uncertainty bound, respectively. The quantification of uncertainty in flood inundation mapping will play a significant role in realizing the efficient flood risk management.

• Food Science and Preservation
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• v.15 no.1
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• pp.49-57
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• 2008

This study was conducted to develop an optimal composite recipe for a cookie including yam powder that would be attractive to all age groups. Wheat flour was partially substituted by yam powder to reduce the content of wheat flour. This study has produced the sensory optimal composite recipe by making cookies, respectively with each 5 level of yam powder $(X_1)$, Sugar$(X_2)$, butter$(X_3)$, by C.C.D (Central Composite Design) and conducting sensory evaluation and instrumental analysis by means of RSM (Response Surface Methodology). Sensory items showed very significant values in color, softness, overall quality (p<0.01), flavor (p<0.05) and those of instrumental analysis showed significant values in lightness, redness (p<0.05), spread ratio, hardness (p<0.01). Also sensory optimal ratio of yam cookie was calculated at yam powder 37.35 g, sugar 50.75 g, butter 78.40 g and it was revealed that the factors of influencing yam cookie aptitude were in older of yam powder, butter, sugar.

• Economic Analysis
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• v.26 no.1
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• pp.84-132
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• 2020

A central bank infers market expectations of future yields based on yield curves. The central bank needs to precisely understand the changes in market expectations of future yields in order to have a more effective monetary policy. This need explains why a range of models have attempted to produce yield curves and market expectations that are as accurate as possible. Alongside the development of bond markets, the interconnectedness between them and macroeconomic factors has deepened, and this has rendered understanding of what macroeconomic variables affect yield curves even more important. However, the existence of various theories about determinants of yields inevitably means that previous studies have applied different macroeconomics variables when estimating yield curves. This indicates model uncertainties and naturally poses a question: Which model better estimates yield curves? Put differently, which variables should be applied to better estimate yield curves? This study employs the Dynamic Nelson-Siegel Model and takes the Bayesian approach to variable selection in order to ensure precision in estimating yield curves and market expectations of future yields. Bayesian variable selection may be an effective estimation method because it is expected to alleviate problems arising from a priori selection of the key variables comprising a model, and because it is a comprehensive approach that efficiently reflects model uncertainties in estimations. A comparison of Bayesian variable selection with the models of previous studies finds that the question of which macroeconomic variables are applied to a model has considerable impact on market expectations of future yields. This shows that model uncertainties exert great influence on the resultant estimates, and that it is reasonable to reflect model uncertainties in the estimation. Those implications are underscored by the superior forecasting performance of Bayesian variable selection models over those models used in previous studies. Therefore, the use of a Bayesian variable selection model is advisable in estimating yield curves and market expectations of yield curves with greater exactitude in consideration of the impact of model uncertainties on the estimation.

• Journal of the Korean Vacuum Society
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• v.14 no.2
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• pp.78-83
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• 2005

Nanometric crystalline silicon (no-Si) embedded in dielectric medium has been paid attention as an efficient light emitting center for more than a decade. In nc-Si, excitonic electron-hole pairs are considered to attribute to radiative recombination. However the surface defects surrounding no-Si is one of non-radiative decay paths competing with the radiative band edge transition, ultimately which makes the emission efficiency of no-Si very poor. In order to passivate those defects - dangling bonds in the $Si:SiO_2$ interface, hydrogen is usually utilized. The luminescence yield from no-Si is dramatically enhanced by defect termination. However due to relatively high mobility of hydrogen in a matrix, hydrogen-terminated no-Si may no longer sustain the enhancement effect on subsequent thermal processes. Therefore instead of easily reversible hydrogen, phosphorus was introduced by ion implantation, expecting to have the same enhancement effect and to be more resistive against succeeding thermal treatments. Samples were Prepared by 400 keV Si implantation with doses of $1\times10^{17}\;Si/cm^2$ and by multi-energy Phosphorus implantation to make relatively uniform phosphorus concentration in the region where implanted Si ions are distributed. Crystalline silicon was precipitated by annealing at $1,100^{\circ}C$ for 2 hours in Ar environment and subsequent annealing were performed for an hour in Ar at a few temperature stages up to $1,000^{\circ}C$ to show improved thermal resistance. Experimental data such as enhancement effect of PL yield, decay time, peak shift for the phosphorus implanted nc-Si are shown, and the possible mechanisms are discussed as well.

• Journal of Korea Technology Innovation Society
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• v.16 no.3
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• pp.582-604
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• 2013

The machinery industry provides infrastructure to many manufacturing industries and it has strong influences on performance and quality of products. However, Korean economic growth has been constantly causing the korean general machinery industry to significantly depend on Japan. To solve this problem, many industrial policies have been tried. In this paper, we divide the value chain of general machinery industry into four steps; technology development step, manufacturing step, marketing step, and after-sales management step. We study the relationships between each of these steps and the awareness of dependency on Japan. For empirical analysis we surveyed 207 domestic companies in general machinery industry. The findings are that the three factors, technology development competency, marketing competency and after-sales management competency have significant relationships with dependence on Japan. Manufacturing competency is not a significant factor. As control variables, the type of manufacturers has effect on dependency on Japan. The company size, the kinds of products and technology levels of products don't have effects on the relationship between the four steps of the value chain and dependency on Japan. To overcome the trade imbalance with Japan in the general machinery industry, we recommend to develop technology development competency, marketing competency, and after-sale management competency. Also we need to adopt industry supporting policies, not depending on all three control variables of company sizes, the kinds of products and the technology levels of products, but depending on the type of manufacturers.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.4
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• pp.127-138
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• 2016

Outsourcing enables firms to use external resources in efficient and effective manner by adopting the best practice of industry. It also helps firms improve their business process which may result in seizing or creating new business opportunity. Collaborating with outstanding BPO(business process outsourcing) providers offer a great deal of advantage that could access to new knowledge, technology, intellectual and material resources that firms do not own. This study was designed to provide in-dept understanding of key elements that may affect the attitude towards BPO of entrepreneurs using 99 samples comprised SME & Venture business owners. Specifically, this study aims to test and analyse the relationship between attitude towards BPO and 4 independent variables including cost reduction, core competence, specialized resources and quality improvement. The analysis results show that core competence, specialized resources and quality improvements have all positive relationships with the attitude towards BPO. However, exceptionally cost reduction is not associated positively with the attitude towards BPO which was against our expectation. Theoretical discussion and practical implication on the analysis results are provided.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.541-549
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• 2015

Research about U.S. and European countries demonstrated that startups and young firms account for nearly all net job creation. If we want to bring down unemployment and to increase economic growth rate, we need to create new companies and to make them to grow. Credit availability is one of the most important factors for entrepreneurs as they attempt to start or expand a business. For young firms, access to credit for business growth can mean the difference between survival and failure. Equity crowdfunding is an innovative means of raising capital for businesses. Crowdfunding campaigns can give new business access to a large pool of investors. This brings huge benefits for marketing and increase provability of success of business and ROI, so it leads follow-on investment from Venture Capital and Angel investors. In Korea, the survival rate of startups and average growth rate of survivors is far lower than those of the U.S or other countries due to lack of funds for startup or early business growth. Equity crowdfunding can be a new funding source for venture or startups. It can increase startup and survival rate, in addition to the growth rate of survivors, resulting in decreased unemployment rate. In Korea, Equity crowdfunding will be available from 2016. Further study is needed to determine whether the impact of crowdfunding in Korea on job creation will be similar to its impact in the U.S.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.765-774
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• 2011

The purpose of this study is to provide informative statistics which can be used for effective Diabetes Management Programs. We collected and analyzed the data of 666 diabetic people who had participated in Korean National Health and Nutrition Examination Survey in 2007 and 2008. Group classification on management behavior of Diabetic Mellitus is based on the K-means clustering method. The Decision Tree method and Multiple Regression Analysis were used to study factors of the management behavior of Diabetic Mellitus. Diabetic people were largely classified into three categories: Health Behavior Program Group, Focused Management Program Group, and Complication Test Program Group. First, Health Behavior Program Group means that even though drug therapy and complication test are being well performed, people should still need to improve their health behavior such as exercising regularly and avoid drinking and smoking. Second, Focused Management Program Group means that they show an uncooperative attitude about treatment and complication test and also take a passive action to improve their health behavior. Third, Complication Test Program Group means that they take a positive attitude about treatment and improving their health behavior but they pay no attention to complication test to detect acute and chronic disease early. The main factor for group classification was to prove whether they have hyperlipidemia or not. This varied widely with an individual's gender, income, age, occupation, and self rated health. To improve the rate of diabetic management, specialized diabetic management programs should be applied depending on each group's character.

• Journal of Navigation and Port Research
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• v.43 no.1
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• pp.72-78
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• 2019

The second-hand ship market provides immediate access to the freight market for shipping investors. When introducing second-hand vessels, the precise estimate of the price is crucial to the decision-making process because it directly affects the burden of capital cost to investors in the future. Previous studies on the second-hand market have mainly focused on the market efficiency. The number of papers on the estimation of second-hand vessel values is very limited. This study proposes an artificial neural network model that has not been attempted in previous studies. Six factors, freight, new-building price, orderbook, scrap price, age and vessel size, that affect the second-hand ship price were identified through literature review. The employed data is 366 real trading records of Panamax second-hand vessels reported to Clarkson between January 2016 and December 2018. Statistical filtering was carried out through correlation analysis and stepwise regression analysis, and three parameters, which are freight, age and size, were selected. Ten-fold cross validation was used to estimate the hyper-parameters of the artificial neural network model. The result of this study confirmed that the performance of the artificial neural network model is better than that of simple stepwise regression analysis. The application of the statistical verification process and artificial neural network model differentiates this paper from others. In addition, it is expected that a scientific model that satisfies both statistical rationality and accuracy of the results will make a contribution to real-life practices.