• 한국정밀공학회지
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• 제26권6호
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• pp.7-13
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• 2009

• 대한지역사회영양학회:학술대회논문집
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• 대한지역사회영양학회 2001년도 춘계학술대회
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• pp.460.1-460
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• 2001

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.966-966
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• 2006

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2006년도 추계학술발표회 초록집
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• pp.76-76
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• 2006

• Journal of Power Electronics
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• 제16권1호
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• pp.84-92
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• 2016

Compared with Si MOSFETs, the GaN FET has many advantages in a wide band gap, high saturation drift velocity, high critical breakdown field, etc. This paper compares the electrical properties of GaN FETs and Si MOSFETs. The soft-switching condition and power loss analysis in a flyback-forward high gain DC/DC converter with a GaN FET is presented in detail. In addition, a comparison between GaN diodes and Si diodes is made. Finally, a 200W GaN FET based flyback-forward high gain DC/DC converter is established, and experimental results verify that the GaN FET is superior to the Si MOSFET in terms of switching characteristics and efficiency. They also show that the GaN diode is better than the Si diode when it comes to reverse recovery characteristics.

• 유통과학연구
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• 제19권8호
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• pp.37-46
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• 2021

Purpose: This study aims at investigating how high-tech SMEs can enhance innovation performance through the application and distribution of social media strategic capability and whether entrepreneurial orientation moderates the relationship between social media strategic capability and innovation. Research design, data, and methodology: The study followed a deductive approach based on the quantitative design in investigating the proposed relationships. The data was collected using a questionnaire, and the proposed relationships were examined based on a sample of 221 high-tech SMEs through the application of structural equation modeling (SEM). By applying SEM, this study accounted for hidden and unobservable factors as well as reconciled the potential measurement errors. Results: As hypothesized, it was confirmed that social media strategic capability positively influences innovation performance. Besides, the findings supported the moderating effect of three dimensions of entrepreneurial orientation (innovativeness, proactiveness, and risk-taking) toward the relationship between social media strategic capability and innovation performance. Conclusions: According to the results, high-tech SMEs can enhance their innovation performance through social media by distributing and applying social media strategic capability along with entrepreneurial orientation. This study thereby enriches the literature of innovation on high-tech SMEs for implementing social media strategies as well as stimulating future social media research for entrepreneurship.

• 영재교육연구
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• 제19권1호
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• pp.141-162
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• 2009

본 연구는 한국과학영재학교 학생들의 과학적 태도, 학습양식, 선호하는 수업형태, 수업환경을 일반계고등학생들과 과학고 학생들과의 비교를 통해 한국과학영재학교 학생들의 학습자 특성을 알아보고, 남녀별 학번별 학습자 특성의 차이를 파악하고자 하였으며 이에 기초한 수업전략을 수립하고자 하였다. 첫째, 한국과학영재학교 학생들의 과학적 태도 수준은 과학고 학생들과 비슷하였으며 일반계 학생들보다 높은 수준이었다. 둘째, 학습양식은 독립형, 협동형, 참여형이 많았다. 셋째, 선호하는 과학수업의 형태는 다양화와 높은 수준의 사고화 요구가 높았다. 넷째, 선호하는 수업환경은 허용적 분위기에 대한 요구가 낮았다 여학생은 남학생보다 과학적 태도에서 개방성, 협동성, 자기주도성의 수준이 높았고, 학습양식은 독립형의 많았으며, 선호하는 수업환경면에서 교사의 지원성과 과제 지향성, 허용적 분위기에 대한 선호가 높았다. 학번에 따른 학습자 특성과 선호도는 차이가 없었다. 이에 따른 수업전략 4가지를 제안하였다.

• 수산해양교육연구
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• 제28권5호
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• pp.1258-1265
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• 2016

The aim of this study was to evaluate the impact on the fishery resources and marine ecosystems by derelict fishing gears as part of the R & E (Research and Education) program that supervised by the busan metropolitan city office of education. In this study, we verified the ghost fishing effects caused by derelict fishing gears through the process which fish were caught to be attracted to bait for gillnet and trap in tank. In results, the dead fish to be gilled in gillnet and to enter in pot have been shown to attract other fish to the bait role. The result showed that the ghost fishing was caused by abandoned, lost or discarded fishing gears continuously. In particular, as a result of pot experiment, if the lost pot has a escape device, the entered fish could escape from the pot and the fisheries resources could protect from derelict fishing gears. In addition, the high school students are capable of raising the problem solving skills through carrying out the research project and expect to contribute to raising awareness about the protection of the marine environment.

• Corrosion Science and Technology
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• 제6권4호
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• pp.159-163
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• 2007

Micron size Co-alloy 800 (T800) powder is coated on the high temperature, oxidation and corrosion resistant super alloy Inconel 718 substrate by the optimal high velocity oxy-fuel (HVOF) thermal spray coating process developed by this laboratory. For the study of durability improvement of high speed spindle operating without lubricants, friction and sliding wear behaviors of the coatings are investigated both at room and at an elevated temperature of $1000^{\circ}F(538^{\circ}C)$. Friction coefficients, wear traces and wear debris of coatings are drastically reduced compared to those of non-coated surface of Inconel 718 substrate both at room temperature and at $538^{\circ}C$. Friction coefficients and wear traces of both coated and non-coated surfaces are drastically reduced at higher temperature of $538^{\circ}C$ compared with those at room temperature. At high temperature, the brittle oxides such as CoO, $Co_{3}O_{4}$, $MoO_2$ and $MoO_3$ are formed rapidly on the sliding surfaces, and the brittle oxide phases are easily attrited by reciprocating slides at high temperature through oxidation and abrasive wear mechanisms. The brittle solid oxide particles, softens, melts and partial-melts play roles as solid and liquid lubricants reducing friction coefficient and wear. These show that the coating is highly recommendable for the durability improvement coating on the machine component surfaces vulnerable to frictional heat and wear.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권1호
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• pp.366-381
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• 2020

Steganography has been successfully employed in various applications, e.g., copyright control of materials, smart identity cards, video error correction during transmission, etc. Deep learning-based steganography models can hide information adaptively through network learning, and they draw much more attention. However, the capacity, security, and robustness of the existing deep learning-based steganography models are still not fully satisfactory. In this paper, three models for different cases, i.e., a basic model, a secure model, a secure and robust model, have been proposed for different cases. In the basic model, the functions of high-capacity secret information hiding and extraction have been realized through an encoding network and a decoding network respectively. The high-capacity steganography is implemented by hiding a secret image into a carrier image having the same resolution with the help of concat operations, InceptionBlock and convolutional layers. Moreover, the secret image is hidden into the channel B of carrier image only to resolve the problem of color distortion. In the secure model, to enhance the security of the basic model, a steganalysis network has been added into the basic model to form an adversarial network. In the secure and robust model, an attack network has been inserted into the secure model to improve its robustness further. The experimental results have demonstrated that the proposed secure model and the secure and robust model have an overall better performance than some existing high-capacity deep learning-based steganography models. The secure model performs best in invisibility and security. The secure and robust model is the most robust against some attacks.