• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.644-652
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• 2013

This paper describes the development and field experiments of Manta-type Unmanned Underwater Vehicle (UUV). Various simulations for Manta UUV are performed by using the nonlinear 6-DOF motion of equations. Through this simulation we verified the motion performances of Manta UUV. To acquire the blueprint of Manta UUV, it was designed with the simulation results. The Manta UUV uses a Doppler Velocity Log (DVL), gyrocompass, GPS, pressure sensor and other minor sensors, applied to measure the motion, position and path of Manta UUV. For its propulsion and changing a direction in the underwater, one vertical fin and four horizontal fins are installed at the hull of UUV. The Manta UUV system was verified with motion and autonomous navigation test at field.

• The Journal of Engineering Geology
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• v.19 no.2
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• pp.131-138
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• 2009

A simulation-optimization model is developed for development of groundwater and control of a saltwater wedge for protecting over-exploiting freshwater pumping wells. To achieve the goal an objective function is developed for three types of wells: freshwater pumping, freshwater injection and saltwater pumping. Integrity of groundwater environment is accounted for by including three indices. Illustrative cross-sectional examples show that both types of barriers can protect freshwater pumping wells from saltwater intrusion. A barrier well operating at the same rate located anywhere within a certain reach can protect a pumping well. However, the location of the reach appears to contradict the common practice of barrier placements. Consideration of the groundwater environment yields a unique optimal location for barrier wells.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.10
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• pp.888-893
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• 2012

This paper described the wind tunnel testing apparatus and technique to acquire the dynamic stability derivatives of large slenderness ratio air vehicle such as the guided missiles or rockets. There have been few difficulties in conducting wind tunnel testing for slender long rocket due to the size limitation of the test section size and the installation of oscillation equipments. In this study, the dynamic stability balance was used as the wind tunnel technique for obtaining the dynamic stability derivatives. Through the wind tunnel testing, the experimental apparatus for slender air vehicle's oscillation is established. The measured data showed that it is possible to acquire the dynamic stability derivatives of large slenderness ratio rocket, properly.

• Journal of Korean Society of Steel Construction
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• v.26 no.3
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• pp.205-217
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• 2014

In this study, flexural strength and ductility requirements of composite hybrid steel I-girder with its HSB(high performance steel for bridge) applied to tension flanges are examined in positive bending. In AASHTO LRFD specification, flexural strength and ductility requirements of composite I-girder in positive bending are specified in terms of plastic moment and plastic neutral axis that are derived from plastic behavior of conventional steel. However, plastic zone cannot be defined clearly from the stress-strain behavior of HSB unlike the behavior of conventional steel. Therefore, through idealized stress-strain curves of HSB, the plastic moment of composite hybrid steel I-girder with its HSB applied to tension flanges is defined by assuming the plastic zone of HSB. By using the consequences of numerical analysis regarding arbitrary cross-sections that have various dimensions, ductility requirements and flexural strength of composite hybrid I-girder with its HSB applied to tension flange are proposed.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1845-1849
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• 2006

본 연구에서는 관측자료에 나타난 Clark 단위도의 매개변수를 검토하고 그 변동성을 평가하였다. 강우-유출과정에 영향을 미치는 유역 및 기상 특성인자들을 확률밀도함수로 정량화하였고, 유역의 집중시간 및 저류상수를 호우사상의 특성 및 유역의 조건을 고려하여 다변량 회귀분석을 실시하였다. 이를 Monte Carlo 모의기법에 적용하여 유역평균 저류상수 및 집중시간에 대한 신뢰구간을 추정하였다. 또한 신뢰구간을 좁히기 위한 방안으로 관측된 집중시간 및 저류상수를 Bootstrap 기법으로 처리하였다. 그 결과 유역을 대표하는 유출특성의 결정에는 관측 강우-유출사상의 수가 어느 정도 확보된다고 하더라도 여전히 높은 불확실성을 피하기 힘들다는 것이다. 집중시간의 경우는 그 분포가 상당히 왜곡된 형태여서 단순한 산술평균은 상당히 왜곡된 추정치를 제시할 가능성이 높다. 단순히 관측치를 이용한 경우보다 Monte Carlo 모의기법에 의한 경우 신뢰구간이 2-3배정도 좁게 나타났다. 어느 정도 신뢰도 있는 집중시간 및 저류상수의 추정을 위해서는 최소 10여개 대략 20개 정도 이상의 호우사상이 필요할 것으로 판단된다. 본 연구의 목적은 주어진 유역을 대표할 수 있는 집중시간 및 저류상수를 결정하고자 하는 것이다. 따라서 본 연구에서의 방법론을 적용하여 관측자료가 존재하는 다양한 유역에서의 집중시간 및 저류상수를 결정하고, 이를 지형인자 유역특성을 고려하여 회귀분석하는 경우 보다 정도 있는 경험식의 개발도 가능할 것이다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.37-42
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• 2004

Shallow $p^{＋}$-n junctions were formed by preamorphization, low-energy ion implantation and dual-step annealing processes. Germanium ions were implanted into silicon substrates for preamorphization. The dopant implantation was performed into the preamorphized and non-preamorphized substrates using B $F_2$2 ions. Rapid thermal anneal (RTA) and furnace anneal (FA) were employed for dopant activation and damage removal. Samples were annealed by one of the following four methods; RTA(75$0^{\circ}C$/10s)＋Ft FA＋RTA(75$0^{\circ}C$/10s), RTA(100$0^{\circ}C$/10s)＋FA, FA＋The Ge Preamorphized sample exhibited a shallower junction depth than the non-preamorphized sample. When the employed RTA temperature was 100$0^{\circ}C$, FA＋RTA annealing sequence exhibited better junction characteristics than RTA＋FA thermal cycle from the viewpoint of junction depth, sheet resistance, $R_{s}$$.$ $x_{j}$, and leakage current.t.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.66-69
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• 1999

To investigate the hormetic effect of the low dose ${\gamma}-ray$, soybean(Glycine max L.) seeds of three cultivars (Hwangkeumkong, Bansakong, S900 cv.) were irradiated with the dose of 0.5∼20.0 Gy and cultivated in the experimental field. The hormetic effects of the low dose ${\gamma}-ray$ on the growth of field experiment were different from each cultivar, that is, more effective in the S900 cultivar of black seedcoat color than in the Hwangkeumkong and Bangsakong of yellow ones. The germination rate of S900 cultivar increased about 30% in the 0.5Gy irradiated group compared with that of the control. The plant height of the 4.0Gy irradiated group in both Bangsakong and S900 cultivar increased 15% more than that of the control. Grain yield and the number of pod in 1.0 Gy and 4.0 Gy irradiated group of S900 cultivar and that of 2.0 Gy irradiated group of Hwangkeumkong increased 25 and 35% on the average, respectively.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.243-255
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• 2020

The purpose of this study is to present the factors that affect business model and product innovation on the enterprise performance of the mobile ecosystem, and to confirm the results of whether they have an effect. To this end, through prior research, business model factors and product innovation factors were defined in the mobile ecosystem that was the mother of the 4th industry, and a hypothesis that each factor will affect corporate performance was established. Through the exploratory surveys and interviews, the value proposition of the business model proved to have a positive (+) effect on the financial and non-disaster performance of the company, and the innovation was proved to have a positive (+) effect on the non-financial performance of the company. It was analyzed that the price competitiveness of product innovation had a positive (+) effect on the financial factors of a company, and the initial market entry had a positive (+) effect on the non-financial factors. With this study, we propose the criteria for reviewing the performance of companies that are rapidly competing in the 4th industrial revolution in terms of business model and product innovation.

• Korean Journal of Human Ecology
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• v.10 no.1
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• pp.33-39
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• 2001

The effects of dipping syrups prepared with isomaltooligosaccharides on the characteristics of Yackwa were investigated. The dipping syrups were prepared replacing sucrose with 0, 25 and 50% isomaltooligosaccharide. Physical and sensory characteristics of Yackwa were evaluated. Isomaltooligosaccharides increased dehydration rate and increased absorption rate of dipping syrups. Yackwas dipping in the syrup containing isomaltooligosaccharides were more acceptable than those with sucrose syrup. The acceptability was significantly correlated with shinness(p<.01), moistness(p<.05), adhesiveness(p<.05), cohesiveness(p<.01), roasted taste(p<.0l) and sweetness(p<.05). Therefore, isomaltooligosaccharides might be a good alternative for sucrose in making dipping syrup of Yackwa.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.144-149
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• 2011

This research has been carried out to examine the effects of quality promoting agents on global quality and epidermal changes of Chamaecereus silvestrii 'Hee-mang' for quality maintenance of the transportation. D-sorbitol than D-mannitol treatment was effective in a lower reduction of fresh weight in C. silvestrii transportations. Application of diniconazole 200 ppm suppressed growth of C. silvestrii. However, it enabled the possibility of long-tenn plant transportation (up to 50 days) and color formation was also effective. As for epidermis structure of C. silvestrii, hypodermis development was lower compared to Gymnocalycium friedrichii and its long-term transportation became poor quality due to single layered, thin cell wall. Application of diniconazole 200 ppm + D-mannitol 10,000 ppm showed higher growth suppressing effects and diniconazole 200 ppm + wax treatment showed better color formation suitable for quality maintenance and storage purposes for C. silvestrii.