• Current Industrial and Technological Trends in Aerospace
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• v.4 no.2
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• pp.25-32
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• 2006

제품보증은 크게 품질보증과 설계보증으로 구분될 수 있으며, 설계보증은 다시 신뢰성 보증, 전자 부품 및 재료 공정 관리, 오염 관리 등으로 구분된다. 품질보증의 경우에는 이미 여러 기업에서 보편적으로 적용되고 있는 개념이며, 항공우주 업계에서도 공인된 민간 인증 체계를 활용하고 있다. 반면 설계보증은 인공위성 등과 같이 운용 중 수리가 불가능한 시스템에서는 특별히 강조되어야 하는 활동이며 안정적인 위성 서비스를 제공하기 위해서는 시스템의 개발 초기부터 체계적인 설계보증 활동이 수행되어야 한다. 이에 따라 각국은 관련 기술 정보를 공유할 수 있는 국가적인 체계를 구축하여 자국 기업들의 경쟁력을 향상시키고 있다. 후발 주자인 우리나라도 이러한 추세에 발맞추어 자체적인 제품보증 기술을 확립하고 국가적인 제품보증 기술 연구 체계를 구축하여 민간 기업의 위성 시장 진출을 촉진시키고 기존 위성 개발 업체의 대외 경쟁력을 높일 필요가 있다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.1
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• pp.93-98
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• 2010

The metal fastening method is the new technology to repair cracks in the casting material using specially designed reverse screws. In this study, we conduct the finite element analysis to analyze the pulling force characteristic of a reverse screw, the core component of the metal fastening method, with respect to the change of the applying torque, frictional coefficient and front screw angle. The simplified analysis model with single screw pitch is proposed for convergency of the non-linear contact analysis. As a results, the pulling force of a reverse screw increase in proportion to the applying torque but exponentially decrease according to frictional coefficient. And also we can find the optimum front screw angle with the largest pulling force is $20^{\circ}$.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.728-734
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• 2007

In this study, we prepared surimi from pork leg and chicken breast by pH adjustments of 3.0 and 11.0. The content of crude protein, yield, water-holding capacity, redness, yellowness, myoglobin(Mb) and metmyoglobin(metMb) were significantly higher in the surimi manufactured from pork leg at adjustment pH 3.0 compared to the other surimi samples; whereas whiteness, myofibrillar protein, breaking force, deformation and gel strength were lower than other samples(P<0.05). The textural attributes were significantly higher in the surimi manufactured from pork leg at adjustment pH 11.0 compared to the other surimi samples; whereas Mb, metMb, cooking loss, breaking force, deformation and gel strength were lower than other samples(P<0.05). Again, the content of crude protein, yield, pH, breaking force, deformation, gel strength and lightness were significantly higher in the surimi manufactured from chicken breast at adjustment pH 3.0 compared to the other surimi samples; whereas myofibrillar protein, redness and metMb were higher than other samples(P<0.05). The content of myofibrillar protein, deformation, lightness and cohesiveness were significantly higher in the suriml manufactured from chicken breast at adjustment pH 11.0 compared to the other surimi samples; whereas Mb, cooking loss, yield and breaking force were higher than other samples(P<0.05). The chicken breast surimi had superior color and gel characteristics than manufactured from pork leg, and adjustment pH 11.0 had superior whiteness and cohesiveness than the pH 3.0 adjusted sample, however, there were no significant differences in sensory attributes among the surimi samples.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.1
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• pp.25-33
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• 1986

Natural river channels usually have a deep section and one or two floodplains, which is called a compound channel. As the general method in the compound channel overestimates the discharge capacity, the momentum transfer due to interaction between the main channel flow and flow over its floodplain must be considered. Scale model experiments are performed for the rectangular main channel with an asymmetrical floodplain. Firstly, velocities are measured at various section grids. Secondary, boundary shear stresses are calculated from velocity distributions. Lastly, in order to determine the apparent shear force, the shear stress distributions are integrated along the wetted perimeter for the full cross-section and equated to the total weight force in the flow direction. The hydraulic characteristics in a compound channel are closely examined with the scales of length, velocity, boundary shear stress, and apparent shear force which are described with the various relationships.

• Journal of Nutrition and Health
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• v.19 no.4
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• pp.233-245
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• 1986

The relationships between nutritional status and psychological functionings in elementart school children were studied using dietary survey, physical and biochemical examinations and psychological measures of both cognitive and personality traits. The results obtained are as follows: (1) Performance of Y school (higher economic class) children on the tests of cognitive functionings, was generally higher than that of B school(lower economic class) children. The means of all anthropornetric measurements were also higher in Y than B school children. (2) Nutrient intakes were found to be positvely correlated with the psychological funtionings of the children to the varing degrees depending on the variables tested. However, the correlations between the physical measures and psychological functionings were low. (3) Most nutrient variables showed positive correlations with body size. (4) The functionings of both cognitive and personality traits are of utmost importance reflecting the positive effects of balanced diet on behavior.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.29 no.3
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• pp.157-177
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• 2018

This study identified problems in reading for future careers and suggests approaches to solve the identified problems by analyzing the fundamental vocational competence and reading for a future career. The study included 457 students in the liberal arts college (humanities and education programs) at "A" university. In accordance with the analysis, communication ability (average 3.61), interpersonal relation ability (3.59), literacy (3.40) and problem solving ability (3.39) were relatively high in fundamental vocational competence, while numeracy (2.72) and entrepreneurship (2.89) were low. Next, 65.2% of those reported no reading for their future career. 46.3% answered 'no time to read books related to my future career.' 25.8% selected 'no books worth reading related to my future career.' 22.5% said 'no curiosity about my future career.' Considering that those who did not read any materials related to a future career reached 65.2% and a number of students had low fundamental vocational competence, this paper suggested the implementation of a systematic educational program for standardizing and strengthening fundamental vocational competence and enhancing understanding of future careers.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.893-897
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• 2004

본 연구는 아이스하버 형태의 어도를 조립식으로 개발하여 실제 현장에 적용하기에 앞서 유량 변화에 따라 어도내 유속 및 유황변화를 조사하고 어도의 배열을 조정하여 어도의 현장적용성을 검토하기 위하여 실시하였다. 모형 월류수심이 40cm(현장 20cm)일 때 상류부는 어류가 소상하기에 적합한 유속을 나타내었고 하류부의 가장 낮은 월류부(좌측열)에서는 어류 소상에 다소 지장을 주는 유속변화를 보였다. 그러나 좌측열을 제외한 우측열과 중간열에서는 어류 이동 및 소상에 적절한 유속변화를 나타내고 있는 것으로 보아 본 어도는 유량 증가에 따라 월류 유속이 증가하여도 월류벽이 높은 구간에서는 유속이 증가폭이 크지 않기 때문에 수위변화에 대응력을 가지는 것으로 판단된다. 다양한 배열로 어도를 설치하면 유속이 느린 어도 구간은 어도 유인수로로서의 역할을 할 수 있으므로 어도내의 다양한 유속은 어류 소상에 유리하게 작용한 것으로 평가된다. 어도의 배열은 월류부의 높이가 높은 것을 좌${\cdot}$우측열에 배열하고 낮은 것을 중간열에 배열하면 갈수량에 대한 대응력이 증가하는 것으로 나타났다. 잠공은 하천의 유량 조건이 좋을 때보다 갈수기나 홍수기에 어류가 소상하는 통로의 역할을 할 수 있을 것으로 판단된다. 따라서, 본 어도는 다양한 월류벽의 배열로 하천의 수위변화에 대한 대응력을 가지고 있으며 구조적으로 견고하여 우리나라 하천 상황에 적절한 어도로 판단된다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.2
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• pp.66-75
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• 1993

Hydraulic experiments were performed in order to gain an insight into the quantitative differences between the perforated wall caisson and its solid wall counterpart in the local pressure distribution and caisson stability. The results showed that the wave forces acting on local walls were smaller in the perforated wall caisson than in the solid wall caisson. For the caisson stability, the critical weights of the perforated wall caisson also turned out to be smaller than those of the solid wall caisson. The Phenomenon was attributed to the dual effects inherent to the perforated wall caisson, which are the decrease of total horizontal force and the phase difference between the total horizontal and vertical forces.

• The Korean Journal of Applied Statistics
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• v.35 no.1
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• pp.93-104
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• 2022

In forecasting realized volatility of the major US stock price indexes (S&P 500, Russell 2000, DJIA, Nasdaq 100), internet search volume reflecting investor's interests and implied volatility are used to improve forecast via a deep learning method of the LSTM. The LSTM method combined with search volume index produces better forecasts than existing standard methods of the vector autoregressive (VAR) and the vector error correction (VEC) models. It also beats the recently proposed vector error correction heterogeneous autoregressive (VECHAR) model which takes advantage of the cointegration relation between realized volatility and implied volatility.

• Journal of Astronomy and Space Sciences
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• v.14 no.1
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• pp.136-141
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• 1997

To calculate the position and velocity of the artificial satellite precisely, one has to build a mathematical model concerning the perturbations by understanding and analysing the space environment correctly and then quantifying. Due to these space environment model, the total acceleration of the artificial satellite can be expressed as the 2nd order differential equation and we build an orbit propagation algorithm by integrating twice this equation by using the Cowell's method which gives the position and velocity of the artificial satellite at any given time. Perturbations important for the orbits of geostationary spacecraft are the Earth's gravitational potential, the gravitational influences of the sun and moon, and the solar radiation pressure. For precise orbit propagation in Cowell' method, 40 x 40 spherical harmonic coefficients can be applied and the JPL DE403 ephemeris files were used to generate the range from earth to sun and moon and 8th order Runge-Kutta single step method with variable step-size control is used to integrate the the orbit propagation equations.