• 한국도로학회논문집
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• 제18권1호
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• pp.57-62
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• 2016

PURPOSES : Reflection cracking has been one of the major causes of distress when asphalt pavement is laid on top of concrete pavement. This study evaluated the reflection cracking resistance of asphalt mixtures reinforced with asphalt embedded glass fiber and carbon fiber using a Texas Transportation Institute (TTI) overlay tester. METHODS : Different asphalt mixtures such as polymer-modified mastic asphalt (PSMA) and a dense graded asphalt mixture were reinforced with asphalt-embedded carbon fiber and glass fiber. For comparison purposes, two PSMA asphalt mixtures and one dense graded asphalt mixture were evaluated without fiber reinforcement. Two different overlay test modes, the repeated overlay test (R-OT) and monotonic overlay test (M-OT), were used to evaluate the reflection cracking resistance of asphalt mixtures at $0^{\circ}C$. In the R-OT test, the number of repeated load when the specimen failed was obtained. In the M-OT test, the tensile strength at the peak load and tensile strain were obtained. RESULTS : As expected, the fiber-reinforced asphalt mixture showed a higher reflection cracking resistance than the conventional nonreinforced asphalt mixtures based on the R-OT test and M-OT test. The dense graded asphalt mixture showed the least reflection cracking resistance and less resistance than the PSMA. CONCLUSIONS : The TTI overlay tester could be used to differentiate the reflection cracking resistance values of asphalt mixtures. Based on the R-OT and M-OT results, the carbon-fiber-reinforced asphalt mixture showed the highest reflection cracking resistance among the nonreinforced asphalt mixtures and glass-fiber-reinforced asphalt mixture.

• Journal of applied mathematics & informatics
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• 제27권5_6호
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• pp.1397-1404
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• 2009

It is the aim of this paper to consider the reflection symmetries of the Genocchi polynomials $G^*_n(x)$. We display the shape of Genocchi polynomials $G^*_n(x)$. Finally, we investigate the roots of the Genocchi poly-nomials $G^*_n(x)$.

• 컴퓨터교육학회논문지
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• 제22권5호
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• pp.27-37
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• 2019

본 연구는 고등학생 대상 온라인 시뮬레이션 기반 HW설계 학습에서 학습자들의 성찰수준을 분석하기 위해, 5차시 HW설계 학습을 실시하고, 차시별 5개 성찰내용에 따른 성찰수준을 분석하였다. 또한 HW설계 학습의 만족도와 필요성을 조사하였다. 차시별 성찰수준 차이 분석 결과, 3차시 D-Flip Flop 학습의 성찰 수준이 1.23점(2점 만점)으로 가장 높았다. 성찰내용 간의 상관관계를 분석한 결과, 학습내용과 과제 해결 방법에서 높은 정적 상관관계(r=.781, p<.01)를, 과제 해결 방법과 다른 해결 방법에서 부적 상관관계(r=-.615, p<.05)를 나타냈다. HW설계 학습 만족도 조사 결과는 4.2점(5점 만점)을 나타냈으며, 대부분의 학생들이 고등학생 대상 HW설계 학습이 필요하고, 현재의 학습내용은 다소 어렵다는 의견이 많았다. 이를 통해 향후 HW설계 학습은 기초-심화로 구성된 콘텐츠와 온 오프라인이 병행된 교육과정 구성이 필요함을 알 수 있었다.

• 대한수학회보
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• 제35권2호
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• pp.269-278
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• 1998

Let ($G,\;{\upsilon}$) be a bounded smooth domain and reflection vector field on $\partial$G, which points uniformly into G. Under the condition that locally for some coordinate system, ${\mid}{\upsilon^i}{\mid}\;i\;=\;1,{\cdot},{\cdot}$,d - 1, where is constant depending on the Lipschitz constant of G, we have tightness for reflected diffusion with jump on G with reflection $\upsilon$ depending only on c. From this, we obtain some properties of L-harmonic function where L is a sum of Laplacian and integro one.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제33권1호
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• pp.35-45
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• 2019

반성적 사고와 메타인지는 학생들의 수학적 사고력 향상에 핵심적인 역할을 한다고 하여도 과언이 아니다. 특히, Schoenfeld(1987)는 메타인지라는 용어에 대해 수학 교사들이 나타낸 반응을 소개하면서 메타인지란 연구자를 위한 전문어일 뿐이며 연구자가 아닌 입장에서 메타인지는 종잡을 수 없는 전문 용어라고 하였다. 이는 메타인지 개념의 불명확성을 나타내고 있다고 하겠다. 따라서 수학교육에서의 반성과 메타인지에 대한 의미를 탐색해 보는 것은 의미 있는 일일 것이다. 본 연구에서는 주요 수학 교수 학습론에서의 반성의 의미를 살펴보고, 또 메타인지의 의미와 역할을 살펴보고 문제 해결 과정에서의 반성과 메타인지를 결부시켜 모색해 봄으로써 궁극적으로 반성과 메타인지에 관한 이해를 도모해 보고자 하였다.

• 한국해양공학회지
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• 제1권1호
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• pp.138-143
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• 1987

Friction welding has emerged as a reliable process for high-production commercial applications with significant economic and technical advantages. But nondestructive test in friction weld was not clearly developed. Therefore the experimental verification is necessary in order to understand the characteristcs of the pulse echo effects according to various change in welding conditions. This paper presents an attempt to determine the relationship between the varios welding conditions and the coefficients of reflection using the ultrasonic pulse echo method in dissibilar metals friction weld. The new approach of calculating the coefficients of reflection based on measured amplitudes of the echoes is applied in this paper. These coefficients provides a single quantitative measurement which involves both acoustic energy reflected at the welded interface as well as transmitted across the interface. As a result, it was known that the quantitave relationship between welding conditions and the coefficients of reflection using the ultrasonic pulse echo exists in dissimilar metals friction weld.

• 통합자연과학논문집
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• 제3권3호
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• pp.138-142
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• 2010

Polystyrene thin films containing Bragg structures have been successfully obtained by the removal of DBR porous silicon films from the DBR structured porous silicon/polystyrene composite film in HF/$H_2O$ mixture solution and by replicating the nano-structures of porous silicon containing Bragg structure. Polystyrene thin films containing Bragg structures displayed unique optical reflection resonances in optical reflection spectrum. This optical reflection band was resulted from the interference of reflection wavelength at Bragg structure of polystyrene thin films. The wavelength of reflection resonances could be modified by the change of Bragg structure of the master. Polystyrene thin films containing Bragg structures were flexible and maintained their optical characteristics upon bending. The Polystyrene thin films replicate the photonic features and the nanostructure of the master.

• The Journal of the Acoustical Society of Korea
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• 제25권1E호
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• pp.1-7
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• 2006

This study examines the reflection characteristic of a thin transition layer of the ocean bottom showing variability with respect to depth. In order to model the surficial sediment simply, we reduce the Biot model to the depth dependent wave equation for the pseudo fluid using the fluid approximation (weak frame approximation). From the reduced equation, the difference between the inherent frequency dependency of the reflection and the frequency dependency resulting from a thin transition layer is investigated. Using Tang's depth porosity profile model of the surficial sediment [D. Tang et al., IEEE J. Oceanic Eng., vol.27(3), 546-560(2002)], we numerically simulated the reflection loss and investigated the contribution from both frequency dependencies. In addition, the effects of different sediment type and varying depth structure of the sediment are discussed.

• 아동학회지
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• 제22권4호
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• pp.115-132
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• 2001

This study examined the effects of mother's parenting and children's reflection on the development of self-control in the resistance to temptation situation. Subjects were 85 3-, 4- and 5- year old children attending educational preschool and their mothers. Each subject's activities were videotaped for 10 minutes in the experimental settings. Children's reflection was evaluated by Kagan's Matching Familiar Figures Test(MFF). Mothers completed a parenting questionnaire. Results showed no age or sex difference in resistance to temptation. Task patience increased with age, and girls had more task patience than boys. Children's resistance to temptation and task patience correlated with children's reflection and mother's parenting. Children's MFF latency and mother's permissiveness-nonintervention predicted children's resistance to temptation. Children's MFF errors, sex, age and mother's warmth-acceptance predicted children's task patience.

• 제어로봇시스템학회논문지
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• 제6권10호
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• pp.894-902
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• 2000

This paper proposes a force reflection control method with a speed saturation compensation scheme for the slave manipulators having a speed saturation due to the high reduction ratio joints. When speed saturation is generated, the proposed force reflection control method not only shows an anti-windup feature in controlling the slave manipulator but also makes the master manipulator move slowly using the force reflection caused by saturation. In this way, the position of the slave manipulator tracks the reference position regardless of speed saturation. The experimental results show that the proposed control method provides excellent performance.