• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.551-551
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• 2017

우리나라와 동아시아는 경제 성장에 따른 전력수요가 크게 증가하였으며, 증가하는 대부분의 전력수요를 원자력으로 대체하고자 원전을 통한 전력생산 비중을 증가시키고 있다. 현재 중국은 13기의 원전을 가동 중이며, 동남 해안지대에 집중되어 있다. 또한, 건설 중인 원전은 27기로 전세계에서 건설 중인 원전의 41%를 차지한다. 원전의 증가에 따른 방사능 누출에 대한 위험성 역시 증가되고 있는 실정이다. 한국원자력안전기술원에서 중국 중서부지역에서 방사능이 누출될 경우 방사성 물질이 한반도로 이동하는 모의 상황에 대한 시뮬레이션을 통해, 원전 사고 발생 시 사흘 만에 제주도를 포함한 대한민국 전역이 방사성 물질로 뒤덮이는 것으로 분석하였다. 중국에서 누출된 방사성물질은 편서풍을 타고 한반도로 이동하게 되며, 일부는 낙진으로 유역 또는 하천에 유입되고 일부는 동해를 지나 일본으로 이동 할 것이다. 그동안 중국에서의 방사능 누출사고를 통한 방사성물질의 국내유입에 의한 영향에 대한 연구가 부족한 것이 현실이다. 이에 본 연구에서는 중국 텐완에서 원전사고 발생시 국내 하천에 어떠한 영향을 미치는지 분석하고자 환경다매체 모형을 이용하여 방사성물질(세슘, Cs-137)의 영향에 대한 모의를 진행하였다. 중국 텐완원전에서 방사성 Cs-137이 누출되어 춘천지역에 도달하였을 때의 대기중 농도 $5,650Bq/m^3$로 가정하여 모의 시나리오를 구성하였다. 모의 지역은 북한강 수계를 대상으로 하였으며, 7개의 중권역과 549.3 km의 하천이 포함되었다. 다매체 모형 모의를 통해 방사성물질 낙진으로 인한 Cs-137이 북한강 수계에 어떠한 영향을 미치는지 알아보고자 북한강수계의 팔당댐 부근의 오염농도를 모의하였다. 우리나라의 원자력시설 방호 방재법에 따른 상수원 취수기준(먹는물)은 100 Bq/L로 되어있다. 본 연구의 시나리오 모의결과, 모의 1일차에서 45 Bq/L, 모의 8일차에는 먹는물 기준 100 Bq/L를 초과하여 최대 119.56 Bq/L로 오염되는 것으로 모의되었다. 따라서, 반감기가 큰 방사성물질을 유입으로 오염된 하천은 개선하기 위해서는 오랜 시간과 높은 처리비용이 발생되기 때문에 인접국 또는 국내의 방사능 누출로 인한 상수원 오염 발생에 대비한 초기/중 장기적인 대응책 마련이 필요한 시점이다.

• Clean Technology
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• v.17 no.3
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• pp.215-224
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• 2011

It is an important issue to develop quality assessing system for biofuel for the purpose of accelerating the mass production of biofuel. It is particularly challenging to conduct testing method in the mass production of bioethanol while meeting quality specifications such as ASTM (American Society for Testing & Materials) D4806-10. In order to address this challenge, this paper proposes on-line spectroscopic quality assesment system based on Near Infrared spectrum and Partial Least Squares method in Chemometrics. As a result of testing a number of preprocessing methods and Partial Least Squares, it was found out that Savitzky-Golay method showed the best performance in terms of spectrum correction, noise reduction, and model maintenance. The proposed system allows us to assess multiple quality components continuously using spectroscopic facilities with the cheap cost. Since the value of R2 is more than 0.99, it is possible to replace the laboratory analysis.

• MARITIME LAW REVIEW
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• v.29 no.2
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• pp.115-144
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• 2017

The impact of the global financial crisis, which began in the United States in 2007, had a major impact on the domestic shipping and shipbuilding industries. In this regard, the domestic shipyard has established an order-taking strategy in several ways as an alternative to lowering the amount of construction of commercial vessels due to deterioration of the shipping industry, and selected industrial sector was the offshore plant sector. However, the domestic shipyard has under performed the offshore plant in order to just increase sales and secure work without any risk analysis for EPC contracts. As a result, the shipyard has been charged more than the initial contract price with the offshore plant contractor, or the shipyard has become a legal issue requiring payment of liquidated damages due to delays in delivery of the product. The main legal disputes are caused by the thorough risk analysis and the inexperience of process control that can occur during offshore plant construction. and In particular, there is no sufficient review of the unequivocal provisions in the contract as an element of risk management. There is no human resource to review these contractual clauses. Therefore, this study identifies the existence of specific risks that could lead to delays in offshore plant construction, and examined the existence of any unequivocal clauses in contracts for offshore plant construction. and also discussed how the toxic clause applies to the actual parties and how the concrete risk factors in the construction contracts are transferred and expressed by referring to the interviews with the project manager of the domestic shipyard and the previous research. As a result, This paper examined the legal liability of the contracting parties regarding delayed delivery of the products due to the offshore plant construction contract. And to improve the domestic shipbuilding industry.

• The Korean Journal of Financial Management
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• v.22 no.1
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• pp.1-36
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• 2005

In this study, we analyzed determinant factors of leverage ratio and debt maturity for Korean firms in the simultaneous equation system using 2SLS (two stage least square) method under assumption that two variables are jointly determined in the capital structure decision. As a result of the analysis, we found that leverage ratio and debt maturity are positively related. Also, as for determinant factors of debt maturity, agency cost hypothesis, asset maturity matching hypothesis, signalling and liquidity risk hypothesis are all generally supported, and further leverage ratio are significantly positively related with firm size, but negatively related with default risk. However, when we divided samples into groups according to bank debt level and Chaebul affiliation, with contrast to existing study which worked on similar issues with OLS, we found no evidence supporting the argument that the information asymmetry problem is less severe in firms with more bank debt, whereas information asymmetry and financial constraint problems are more severe in non-Chaebul affiliated firms.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.13-13
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• 2009

현재 열간단조 금형을 제작함에 있어 육성용접을 실시하는 방법이 금형강 STD61, STD11 등으로 제작하는 방법에 비해 보수나 비용적인 측면에서 이점을 가지고 있기 때문에 점차적으로 증가하고 있는 추세이다. 열간단조 공정에서 금형은 $1000^{\circ}C$이상의 고온재료와 반복접촉하게 된다. 이때 이형제의 사용은 급속냉각 및 급속가열의 열피로를 가속시킨다. 또한, 금형은 반복충격에 의한 기계적 피로를 받게 된다. 이러한 금형의 사용환경을 고려한 FCW는 종래 고가의 $2.8{\sim}3.2{\Phi}$인 외국산 FCW를 사용하였으나 이를 대체한 $3.2{\Phi}$ 태경 FCW가 국내에서 개발되었다. 하지만 개발된 FCW를 사용하여 제작된 금형의 수명이 부족한 현상이 발생하였다. 이에 금형의 수명을 연장시킬 수 있는 내균열성 및 내열충격성을 확보한 태경 FCW의 개발과 개발된 FCW의 성능평가가 요구되었다. 특히 열간단조 금형에 있어서 중요한 내열충격성의 경우 가열과 냉각의 반복 Cycle에 의한 Thermal shock의 평가가 대부분이며 높은 Cycle로 인해 많은 시간이 걸리며, 또한 가열과 냉각을 오갈 수 있는 고가의 시험장치가 요구된다. 그러므로 개발된 FCW 육성용접부의 내균열성 및 내열충격성을 평가할 수 있는 방법에 대한 연구와 특히 내열충격성을 시간이 적게 걸리면서도 경제적으로 평가할 수 있는 방법에 대한 연구가 필요하다. 본 연구의 목적은 열간단조 금형 육성용접부의 내균열성 및 열충격특성을 평가할 수 있는 방법에 대한 검토와 특히 내열충격성에 대해 J.W.Kim등의 시험방법을 참고하여 시간이 적게 걸리면서 저 비용으로 열 충격특성을 평가할 수 있는 시험법을 고안하는 것이다. 이를 위한 방법으로 육성용접부의 내균열성을 평가하기 위한 상온 Bending을 실시하였고, 내열충격성을 평가하기 위한 염욕로를 이용하는 고온 Bending을 고안하여 실시하였다. 상온 Bending, 고온 Bending 모두 3점 굽힘시험을 적용하였다. 고온 Bending의 가열방법으로는 염욕로를 사용하여 시편이 대기중에서 약 $850^{\circ}C$의 온도가 될 수 있도록 하였다. 시편은 각각 열처리를 하여 요구 경도를 확보하였고, 이를 염욕로에서 5분간 가열 및 유지하여 취출 후 굽힘하중을 가하여 변위의 정도로 열충격을 평가하는 방법을 사용하였다. 상온 Bending은 극한변형량과 파단부 극한응력으로, 고온 Bending은 고온 극한변형량으로 평가를 하였고, 외국산 FCW를 사용한 육성용접부를 비교대상으로 하였다. 평가 결과 개발된 국산 $3.2{\Phi}$ 태경 FCW의 성능은 외국산 FCW와 유사하거나 우수한 것으로 평가되었고, 실제 금형을 제작하여 현장에 적용한 결과 금형의 수명이 연장된 것이 나타났다.

• The Korean Society of Law and Medicine
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• v.15 no.1
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• pp.335-373
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• 2014

According to one Medicare report, in the US, total federal spending on health care expends almost 18 percent of the nation's GDP, about double what most industrialized nations spend on health care. And in 2011, Medicare spending reached close to $554 billion, which amounted to 21 percent of the total spent on U.S. health care in that year. Of that $554 billion, Medicare spent 28 percent, or about $170 billion, on patients' last six months of life. So what are the reasons of this high cost in EOL care and its possible solutions? Much spendings of Medicare on End-of-Life care for the terminally ill/chronically ill in the US has led health economics experts to assess the characteristics of the care. Decades of study shows that EOL care is usually supply-sensitive and poor in cost-effectiveness. The volume of care is sensitively depending on the supply of resources, rather than the severity of illness or preferences of patients. This means at the End-of-Life care, the medical resources are being overused. On the other hand, opposed to the common assumption, "The more care the better utility", the study shows that the outcome is very poor. Actually the patient preference and concerns are quite the opposite from what intense EOL care would bring about. This study analyzes the reasons for the supply-sensitiveness of EOL care. It can be resulted from the common misconception about the intense care and the outcome, physicians' mission for patients, lack of End-of-Life Care Decision which helps the patients choose their own preferred treatment intensity. It also could be resulted from physicians' fear of legal liabilities, and the management strategy since the hospitals are also seeking for financial benefits. This study suggests the possible solutions for over-treatment at the End-of-Life resulting from supply-sensitiveness. Solutions can be sought in two aspects, legal implementation and management strategy. In order to implement advance directive properly, active ethics education for physicians to change their attitude toward EOL care and more conversations about end-of-life care between physicians and patients is crucial, and incentive system for the physicians who actively have the conversations with patients will also help. Also, the general education towards the public is also important in the long run, and easy and official advance directive registry system-such as online registry-has to be built and utilized more widely. Alternative strategies in management are also needed. For example, the new strategic cost management and management education, such as cutting unnecessary costs and resetting values as medical providers have to be considered. In order to effectively resolve the problem in EOL care for the terminally ill/chronically ill and provide better experience to the patients, first of all, the misconception and the wrong conventional wisdom among doctors, patients, and the government have to be overcome. And then there should be improvements in systems and cultures of the EOL care.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.592-601
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• 2015

Rubus coreanus is known as Korean black raspberry, native to Korea, Japan, and China. Preliminary studies evaluating their potential for cancer treatment in mammalian test systems are ongoing. In recent years, interest has been renewed due to their high levels of anthocyanins. Anthocyanins in black raspberry are important due to their potential health benefits as dietary antioxidant, anti-inflammatory compound, and as a chemopreventive agent. In the present study, Saccharomyces cerevisiae BA29 was isolated from black raspberry fruit and fruit juice as a biogenic amine non-producing strain for manufacturing of black raspberry wine, after which we investigated its characteristics: biogenic amine-producing ability, cell growth ability, alcohol-fermentation ability, and resistance to alcohol, glucose, and sulfur dioxide. Based on preliminary experiments, we optimized culture medium compositions for improving dried cell weight of S. cerevisiae BA29 by response surface methodology (RSM) as a statistical method. Design for RSM used a central composite design, and molasses with the industrial applicability was used as a carbon source. Through statistical analysis, we obtained optimum values as follows: molasses 200 g/L, peptone 30 g/L, and yeast extract 40 g/L. For the model verification, we confirmed about 3-fold improvement of dried cell weight from 6.39 to 20.9167 g/L compared to basal yeast peptone dextrose medium. Finally, we manufactured black raspberry wine using S. cerevisiae BA29 and produced alcohol of 20.33%. In conclusion, S. cerevisiae isolated from black raspberry fruit and juices has a great potential in the fermentation of black raspberry wine.

• Progress in Medical Physics
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• v.14 no.3
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• pp.151-160
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• 2003

The application of more complex radiotherapy techniques using multileaf collimation (MLC), such as 3D conformal radiation therapy and intensity-modulated radiation therapy (IMRT), has increased the significance of verifying leaf position and motion. Due to thier reliability and empirical robustness, quality assurance (QA) of MLC. However easy use and the ability to provide digital data of electronic portal imaging devices (EPIDs) have attracted attention to portal films as an alternatives to films for routine qualify assurance, despite concerns about their clinical feasibility, efficacy, and the cost to benefit ratio. In this study, we developed method for daily QA of MLC using electronic portal images (EPIs). EPID availability for routine QA was verified by comparing of the portal films, which were simultaneously obtained when radiation was delivered and known prescription input to MLC controller. Specially designed two-test patterns of dynamic MLC were applied for image acquisition. Quantitative off-line analysis using an edge detection algorithm enhanced the verification procedure as well as on-line qualitative visual assessment. In conclusion, the availability of EPI was enough for daily QA of MLC leaf position with the accuracy of portal films.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.2
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• pp.237-248
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• 2014

Linear cutting test is known to be very effective to determine machine parameters (i.e. thrust force and torque) and to estimate penetration rate of TBM and other operation conditions. Although the linear cutting test has significant advantages, the test is expensive and time-consuming because it requires large size specimen and high load capacity of the testing machine. Therefore, a few empirical prediction models (e.g. CSM, NTNU and QTBM) alternatively adopt laboratory index tests to estimate design parameters of TBM. This study discusses the estimation method of TBM machine parameters and disc cutter consumption using punch penetration test and Cerchar abrasion test of which the researches are rare. The cutter forces and cutter consumption can be estimated by the empirical models derived from the relationship between laboratory test result with field data and linear cutting test data. In addition, the estimation process was programmed through which the design parameters of TBM (e.g. thrust, torque, penetration rate, and cutter consumption) are automatically estimated using laboratory test results.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.215-224
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• 2018

Influences of the magnetic field on 5, 10 and 15 wt% (1.5, 3 and 4.5 M) HCl solution behaviour, which has widespread applications in petroleum well acidizing, were investigated in various conditions. Differences in the pH of magnetized hydrochloric acid compared to that of normal hydrochloric acid were measured. Taguchi design of experimental (DoE) method were used to model effects of the magnetic field intensity, concentration, velocity and temperature of acid in addition to the elapsed time. The experimental results showed that the magnetic field decreases [$H^+$] concentration of hydrochloric acid up to 42% after magnetization. Increasing the magnetic field intensity (with 28% contribution), concentration (with 42% contribution), and velocity of acid increases the effect of magnetic treatment. The results also demonstrated that the acid magnetization was-not influenced by the fluid velocity and heating. It was also displayed that the acid preserves its magnetic memory during time. The optimum combination of factors with respect to the highest change of [$H^+$] concentration was obtained as an acid concentration of 10% and an applied magnetic field of 4,300 Gauss. Due to the reduction of HCl reaction rate under the magnetization process, it can be proposed that the magnetized HCl is a cost effective and reliable alternative retarder in the matrix acidizing of hydrocarbon (crude oil and natural gas) wells.