• 지질공학
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• 제20권2호
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• pp.155-167
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• 2010

사면의 안정성 분석에 결정론적인 방법이 최근까지 많이 사용되어 왔으나, 암반의 불확실성과 가변성을 고려하는 확률론적인 방법이 더욱 효과적인 것으로 알려지면서 확률론적인 방법의 사용이 점차 증가하는 추세이다. 그러나 현재까지의 방법들은 절리의 특성이나 암반의 풍화 특성 등과 같은 암반의 특성이 사면 전체에서 균질한 것으로 가정하고 있으며, 암반 사면의 파괴에 가장 결정적인 변수인 절리의 연장성을 고려하지 않은 상태에서 안전율 혹은 파괴확률을 계산하여 사면의 안정성을 분석하고 있어서 정확한 사면 안정성 분석에 한계를 보이고 있는 실정이다. 이 연구에서는 모델 사면을 설정한 후, 사면이 균질하다고 가정한 경우와 사면을 암반 및 절리의 상태에 따라 구역으로 분할한 경우의 파괴확률을 계산하여 비교하였고, 또한 위의 각각의 경우에 절리의 연장성을 변수로 고려한 파괴확률을 계산하였다. 또한 강원도 홍천군에 위치한 사면을 구역으로 분할한 후 절리의 연장성을 고려한 파괴확률을 계산하여 모델 분석의 적용성을 검증하였다.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.821-827
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• 2014

An isotope dilution liquid chromatography tandem mass spectrometry (ID LC-MS/MS) method has been developed and applied to the determination of arsenobetaine (AsB, ${(CH_3)_3}^+AsCH_2COO^-$) from oyster candidate certified reference material (CRM). The exact matching isotope dilution approach was adopted for accurate determination of AsB using $^{13}C_2$-labeled AsB as an internal standard. Efficiencies of different AsB extraction methods were evaluated using a codfish reference material and a simple sonication method was selected as the method of choice for the certification of the oyster candidate CRM. The hydrophilic interaction liquid chromatography (HILIC) combined with electrospray ionization tandem mass spectrometry (ESI/MS/MS) in selected reaction monitoring (SRM) mode was optimized for adequate chromatographic retention and robust quantification of AsB from codfish and oyster samples. By analyzing 12 subsamples taken from each 12 bottles systematically selected from the whole oyster CRM batch, the certified value of AsB was determined as $6.60mg{\cdot}kg^{-1}{\pm}0.31mg{\cdot}kg^{-1}$ and it showed excellent between-bottle homogeneity of less than 0.42%, which is represented by relative standard deviation of 12 bottles from the CRM batch. The major source of uncertainty was the certified value of the AsB standard solution.

• 기술혁신연구
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• 제26권4호
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• pp.1-28
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• 2018

자동차 부품기업들은 플랫폼 기반 대량맞춤형 제품개발과 생산을 통해 비용절감과 아시아 신흥시장 수주 확대를 목표로 하고 있다. 그러나 신흥시장은 수주량이 적고, 변동성이 높아 목표 달성이 어렵다. 본 연구는 부품기업 관점에서 신흥시장의 수주량 변동성 위험을 적정 수준으로 관리하면서, 영업이익을 극대화할 수 있는 제품 포트폴리오 최적화 방법을 제안한다. 기존 제품 포트폴리오 최적화 접근법과의 차별점은 세가지다. 첫째, 플랫폼 기반 대량맞춤형 생산에 의한 비용 절감효과를 반영한다. 둘째, 수주량 변동성을 고려한다. 셋째, 최소 영업이익률 유지라는 강건성 조건을 반영한다. 실무적으로는 신흥시장 개척의 재무 위험을 최소한도로 유지하면서, 점진적으로 시장점유율을 높여가는 동적 제품개발 전략 수립의 토대를 제공한다. 북미, 유럽, 아시아 18개 업체에 납품하는 다국적 부품제조기업의 파워리프트게이트 제품을 대상으로 실증연구를 수행했다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.269-276
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• 1999

The program ESRAS Ver 0.5 that can assess the risk of slopes by means of fuzzy inference is developed in this paper. The results of assessment involve the degree of stability of slopes, the possible travel distance of the soil mass being failed, and anticipated loss of life and properties. With this program, vulnerable slopes can be managed most effectively and the fuzzy inference is used to express quantitatively the judgement of an expert and the uncertainty of slope stability. The fuzzy rule base is composed of an evaluation list for slope stability together with the experience of an expert. This program has been examined for 88 slopes which have been failed or shown a possibility of failure. With this examination, the standards to assess the stability of slopes can be presented and it is proven that this is particularly useful in determining the priority of investment for remedial works of slopes.

• 설비공학논문집
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• 제24권1호
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• pp.9-15
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• 2012

An effectiveness model has been developed from the approximate analytical solution of a rotary desiccant wheel. The resulting equations clearly show that the maximum air temperature and humidity differences are two independent driving forces commonly acting in the heat and mass transfer processes. Comparison with the numerical model from the preceeding study revealed that the effectiveness model could make realistic predictions roughly with 10% uncertainty. The model may be useful for the rough design and analysis of desiccant evaporative cooling systems.

• 대한기계학회논문집
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• 제19권6호
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• pp.1371-1381
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• 1995

A novel hybrid control scheme to actively control the endpoint position of a very flexible single-link manipulator is proposed. The control scheme consists of a motor mounted at the beam hub and a piezofilm actuator bonded to the surface of the flexible link. The control torque of the motor to produce a desired motion is firstly determined by employing the sliding mode control theory on the equation of motion of the rigid link having the same mass as that of the proposed flexible link. The torque is then applied to the flexible manipulator in order to activate the commanded motion. During the motion, undesirable oscillation is actively suppressed by applying a feedback control voltage to the piezofilm actuator. Consequently, the imposed desired position is accomplished. In order to demonstrate high control performances accrued from the proposed method, computer simulations are undertaken by treating both regulating and tracking control problems.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.125-132
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• 2000

This study presents the application of genetic algorithms(GA) to the back analysis of tunnels. GA based on the theory of natural evolution, and have been evaluated very effective for their robust performances, particularly for optimizing structure problems. In the back analysis method, the selection of initial value and uncertainty of field measurements influence significantly on the analysis result. GA can improve this problems through a probabilistic approach. Besides, this technique have two other advantages over the back analysis. One is that it is not significantly affected by the form of problems. Another one is that it can consider two known parameter simultaneously. The propriety of this study is verified as the comparison in the same condition of the back analysis(Gens et al, 1987). In this study, it was performed to estimated the geotechnical parameters in the case of weak rock mass at the Kyung Bu Express railway tunnel. GA have been shown for effective application to a geotechnical engineering.

• 동력기계공학회지
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• 제20권4호
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• pp.38-43
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• 2016

Safety-related equipments of Nuclear Power Plants(NPP) have to perform environmental qualification test in accordance with IEEE-323 standards. However, non-metallic materials replace new one regularly instead of the test because they are considered as consumable parts. In this study, the seven kinds of non-metallic materials are selected and their activation energy was experimentally evaluated with uncertainty analysis by using thermogravimetric analyzer(TGA). In order to obtain activation energy of non-metallic materials, mass difference, temperature raising rate and conversion rate on the specimen are analyzed. It is postulated that the three experiment conditions are important to get a reliable activation energy. This postulate was experimentally confirmed using Arrhenius equation and Flynn-Wall-Ozawa analysis.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.22.1-22.1
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• 2008

Media company is not a business which sells news and information but a company sells audience's attention. Advertisers estimate audience's quantity and quality which pay attention to media and pay the cost. Thus drawing audience's attention is a natural and instinctive behavior for survival of media company. News doesn't deliver the fact just as it. That's impossible. News is a commodity made by processing and selection of the media company and journalist. On the process, judge of values is involved and limitation of time and place of media is considered. If scientists understand media's character truly, their misunderstanding about media company and journalist may be cleared up. In this society, media is not a being to ignore, particularly for big science like space science which spends huge public capital. Nowadays, space science meets the time to take the leap in Korea. However that can be crisis cause of uncertainty of science activity. When the crisis which no one desires happens, preparation needs for new opportunity. We can take the crisis as a chance. Understanding about media and public will be the first step for this preparation.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1995년도 춘계공동학술대회논문집; 전남대학교; 28-29 Apr. 1995
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• pp.967-973
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• 1995

A neutral particle beam(NPB) aimed at the object and receive a small number of neutron signals at the detector to estimate the mass of an object Since there is uncertainty about the location of the axis of the beam relative to the object, we could have aiming errors which may lead to incorrect information about the object. Under the two assumptions that neutral particle scattering distribution and aiming errors have a circular normal distribution respectively, we have derived an exact probability distribution of neutral particles. It becomes a Poison-power function distribution., We proved monotone likelihood ratio property of tlis distribution. This property can be used to find a criteria for the hypothesis testing problem.