• Journal of the Korean School Mathematics Society
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• v.17 no.4
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• pp.589-611
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• 2014

Since most people experience mathematics anxiety(MA), the research on mathematics anxiety has been the main theme in the research of mathematics education. The study of brain science related to MA has recently been begun due to the advent of apparatuses so this study might have revisited MA as time passed and aimed to obtain realistic implications for the future study. For this purpose, we analyzed previous studies how to measure MA and how to develop the intervention to reduce MA. As the result, the researchers based on brain science studied the relevance of specific parts of the brain according to the degree of MA using only simple computational tasks. The research for developing the MA scale has upgraded how to measure both the cognitive and affective domains with more efficient ways. The research on intervention for MA has developed the programs using systematic desensitization, clinical counseling, STAD teaching method, writing methods, etc. However, we realized that more specified and reliable studies to solve the MA must be done in the future.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.535-543
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• 2014

In the robust optimization field, the robustness of the objective function emphasizes an insensitive design. In general, the robustness of the objective function can be achieved by reducing the change of the objective function with respect to the variation of the design variables and parameters. However, in conventional methods, when an insensitive design is emphasized, the performance of the objective function can be deteriorated. Besides, if the numbers of the design variables are increased, the numerical cost is quite high in robust optimization for nonlinear programming problems. In this research, the robustness index for the objective function and a process of robust optimization are proposed. Moreover, a method using the supremum of linearized functions is also proposed to reduce the computational cost. Mathematical examples are solved for the verification of the proposed method and the results are compared with those from the conventional methods. The proposed approach improves the performance of the objective function and its efficiency.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.3
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• pp.41-46
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• 2020

In this study, measurement and analysis results from Differential scanning calorimetry(DSC) and Thermogravimetric analysis(TGA) on the newly developed high-energy thermoplastic elastomer(ETPE) propellant are described, followed by the previous study done under the same title as this paper [1]. The characteristics of high-energy thermoplastic propellant were also verified by conducting thermal analysis, and the LSGT, Shotgun & RQ Bomb test, was carried out as well. High energetic thermoplastic binders containing 45% of GAP(Glycidyl Azide Polymer), energetic plasticizer(DEGDN) and Oxidizer Aonium Perchlorate), RDX(reseach development explosive, cyclotrimethylenetrinitramine) were used to formulate the propellant.

• Korean Journal of Optics and Photonics
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• v.19 no.1
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• pp.1-8
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• 2008

Shack-Hartmann sensors are widely employed as a wavefront measuring device in various applications. Adaptive optics is one of the major applications. Since an adaptive optics system should be operated in real-time, high-speed wavefront sensing is essential. In high-speed operation, integration time of an image detector is very short. In this case, noises such as readout noise and photon noise greatly influence the accuracy of wavefront sensing. Therefore a fast and noise-insensitive centroid finding algorithm is required for the real-time wavefront sensing. In this paper, the multi-resolution correlation method is proposed. By employing multi-resolution images, this method greatly reduces the computation time when compared to the fast Fourier transform (FFT) correlation method. The verification is performed through the computational simulation. In this paper, the center of mass method, correlation method and multi-resolution correlation method are employed to compare the measurement accuracy of the centroid finding algorithms. The accuracy of a Shack-Hartmann wavefront sensor using the proposed algorithm is proved to be comparable to that of the conventional correlation method.

• Journal of dental hygiene science
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• v.17 no.1
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• pp.46-55
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• 2017

Many people in Korea suffer from a fear of dental treatments; however, only a few studies have focused on this population. This study assessed the effectiveness of cognitive behavioral therapy (CBT) and its interventions in reducing dental anxiety, especially when administered by trained dental staff. Using case studies, the authors analyzed the content of each session and examined the process of reducing dental anxiety. First, the authors observed that the results of both dental fear scale and subjective unit of disturbance decreased significantly with changes in cognitive distortions related to dental anxiety and that rapid improvements were noted after two therapy sessions. Second, the study reported that practicing relaxation (deep-breathing) and muscle relaxation techniques; using hand signals to indicate anxiety or discomfort; establishing an empathic relationship with the therapist; making an anxiety list; and graded insensitive and exposure along with rehearsal, were effective in coping with dental anxiety and in changing negative thoughts towards the dentist. Third, a simple cognitive behavioral intervention can be effective in reducing dental anxiety. In summary, a short-term, five-session psychological intervention with CBT produced a sustained decrease in the symptoms of dental anxiety, allowing the patients to receive the required procedures. The authors discussed the study limitations and the implication of their results on future research.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.4
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• pp.147-157
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• 1987

Five finite difference schemes (explicit, Bresler, implicit, upstream, and Chaudhari scheme) for the convective dispersion model are analyzed numerically to investigate their characteristics and applicabilities. Camparative study results show that the conditionally stable Chaudhari scheme has the smallest numerical dispersion and that the unconditionally stable Bresler scheme has the overshooting in regions of oscillation. Explicit scheme is the most accurate for a dispersion-dominated flow whereas Chaudhari scheme is for a convection-dominated flow. The computation time (CPU) is the shortest for the explicit or Chaudhari scheme with the same order of magnitude and is always the longest for the Bresler scheme.

• Journal of Biomedical Engineering Research
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• v.16 no.3
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• pp.353-358
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• 1995

The impedance pneumography which is widely used in monitoring respiration is simple to use and noninvasive, but it is sensitive to motion artifacts and insensitive to detect obstructive apnea. A 3-channel respiratory inductive plethysmography (RIP) developed in this study detects inductance change of the inductance band induced by cross-sectional area change of thorax or abdomen as one breathes. It was confirmed that RIP was less sensitive to various motion artifacts but more sensitive to detection of obstructive apnea than impedance pneumography.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.4
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• pp.402-410
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• 2002

Recently the necessity of study on optical measuring method using laser to detect the pipeline's defect in nuclear facilities, chemical industries and power plants has been increased. Because laser light can be delivered to a remote area without any difficulties, the application of laser in many industries can solve several difficulties from the limitation of access in danger area and reduce the risks of workers. Therefore, we applied a new experimental technique to the measurement of internal defects in pressure vessels with the combination of shearography and image processing technique and detected the internal cracks of pressure vessels in the former paper. In this paper, we used the same optical system as in the former study and found the optimum shearing magnitude by comparing the real length of specimen with experimental results. A variety of conditions were applied to certify the validity of this method. Actually, several specimens which have different lengths and depths were used in this experiment under the three diverse pressure. Consequently, we have carried out this experiment to determine the limit of measurement ability with analyzing errors.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2004.05a
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• pp.112-117
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• 2004

본 연구에서는 쏠더를 이용한 새로운 웨이퍼 레벨 실장 기술을 제안하였고 순수 주석도금이 쏠더로서 이용되었다. 제안된 실장 기술의 가장 큰 차별성은 레고 조립처럼 어셈블리 한 후에 쏠더 리프로우를 통해 측면 접합한다는 것이다. 이런 측면 접합 기술은 기본적으로 표면 상태에 매우 둔감하다는 장점과 비아를 통한 전기적 연결 시 끝 단의 노칭(notching)에 의한 전기적 연결 끊김 문제를 해결할 수 있다. 접합강도는 전단 응력을 측정하여 평가하였고, 실장의 기밀성(Hermeticity)는 가압 헬륨 측정법을 통해서 평가되었다. 실험결과로부터 본 실장 기술은 고 수율 웨이퍼 레벨 실장 기술의 대안이며 실행 가능함을 확인할 수 있었다.

• The Journal of the Korea Contents Association
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• v.3 no.2
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• pp.31-38
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• 2003

This paper proposes method to insert soong Watermark considering dull HVS properties to big change of Edge and Texture area. While conversion of existent Fourier form can acquire information for whole frequency ingredient of image, but Wavelet transform can look for Edge and Texture area locally. Therefore, use Wavelet transform to use HVS properites, and compare with Xia's Watermarking techniques to use Wavelet transform simply arid experimented these proposal algorithm. Experimented about fidelity and robusthness by attack method that is used in existing paper, and as a result, confirmed that proposal algorithm that use HVS properties is more superior than Xia's techniques.