• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.420-420
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• 2007

ZnO 나노막대는 산화물 반도체로서 넓은 밴드캡 (3.37eV)을 가진 반도체이며, 테라급의 전계 효과 트랜지스터(FET), 대기오염물질 모니터링 센서, 태앙전지용 전극, UV 발광소자, 전계방출 디스플레이의 팀 등 나노기술 전반에 활용해 최근 각광을 받고 있는 물질이다. 최근 디바이스 응용의 효율을 높이기 위한 방편으로 나노막대에서 박막으로의 연구가 활발하다. 본 실험은 MOCVD률 이용하여 p-si 기판위에 나노막대를 성장시킨 후 압력 및 온도 등의 공정변수를 조절하여 나노막대에서 박막으로 성장형태를 변화시켰다. SEM으로 1 차원 나노막대에서 2차원의 나노박막으로 성장이 된 ZnO 하이브리드 구조를 확인할 수 있었다. 또, PL장비를 이용해 ZnO의 UV영역의 파장을 확인할 수 있었다.

• KIEAE Journal
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• v.17 no.5
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• pp.43-50
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• 2017

Purpose: Residential cooking(gas or electricity) emits many air pollutants. For Removal of these contaminants, range hood is play an important role in the cooking activities. However, deterioration about performance of range hood can be occur in used range hood which is not verified on performance by testing balancing and adjusting in apartment. So, purpose of this study is to improve the range hood against cooking-generated contaminations. Method: To improve hood, survey of range hood which mounted in apartment have to conduct at first. In this study, the survey was conducted for 3 steps. First, Visual inspection for conditions of range hood. Second, questionnaire of operating and maintenance method. Third, interview with user about need for improvement, complainant. Finally, we integrated the survey for range hood and introduced the probable cause of deterioration through this comprehensive survey. Result: Result of measurement for air volume for range hood, A measured air volume has reduced by 41.4, 38.0, 32.0% each step from rated air volume. There are lots of reasons of this phenomenon including to maintenance, air path of duct, lower-cost devices, exhaust ports. For solve this problem, guideline about operating hood, user in apartment will have to supply with maintenance information at first.

• The Korean Journal of Food And Nutrition
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• v.30 no.5
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• pp.960-972
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• 2017

The objectives of this study was to investigate the properties and stability of the wet noodles added to nanoemulsion as a industrial model system, and in so doing, survey practical applicability in the food industry. In order to test out these objectives, the characteristics and stability of the wet noodles added to nanoemulsion were investigated and their cooking characteristics and capsaicinoids loss were examined. As a result, the test results showed that the findings indicated that the post-cooking loss of capsaicinoids in the wet noodles added to double-layer nanoemulsion covered with chitosan was less than the losses in the wet noodles added to any other noodles. More especially, this demonstrates that the noodle added to double-layer nanoemulsion covered with chitosan scored significantly higher than the others with reference to their cooking properties, color, texture, stability for storage stability, and sensory evaluation. These results show that the findings of this study demonstrated that the noodles added to nanoemulsions could be produced as a food-grade merchandise because they could provide enhanced encapsulation capacity of capsaicinoids and higher acceptability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2623-2627
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• 2014

The objective of this study is to experimentally investigate the heat transfer characteristics of 200W woofer speaker unit with the input voice signals such as 500 Hz, 1000 Hz, 2000 Hz, and 3000 Hz. The temperature and heat transfer characteristics of the woofer speaker unit were evaluated with the input signals. As results. the temperature of the voice-coil for woofer speaker unit increased with a decrease of the input signals and the temperature differences between parts of the tested speaker unit increased with the decrease of the input voice signals. In addition, the voice-coil temperature for the input signal of 500 Hz showed 48.4 % lower than that of 3000 Hz during 18000 sec.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.06a
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• pp.95-99
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• 2011

최근 무료 WiFi Zone이 확대되고 있고, Smart Phone으로 무료 WiFi에 접속하여 인터넷으로 접속하여 메신저를 하거나, 메일확인, 정보검색 등을 한다. 하지만 무료 WiFi Zone에서 Smart Phone으로 인터넷을 할 때, 개인정보를 해킹 당 할 수가 있다. 본 논문에서 안드로이드 O,S, Smart Phone에서 무료 WiFi를 이용하여 접속한다. 먼저 메신저와 웹사이트 로그인을 한다. 이때 AirPcap을 이용하여 패킷을 캡처한다. Packet 분석 툴인 WireShark를 사용하여 Packet의 내용을 분석하고, ID, PW와 메신저 대화 내용을 해킹한다. 해킹한 개인정보 ID, 비밀번호를 이용하여 인터넷 사이트에 접속을 하여 관리자 권한을 획득한다. 그리고 Smart Phone에서 WiFi접속 시 공격에 대한 보안대책을 제시한다. 본 연구는 Smart Phone에서 무료 WiFi 접속 때, 보안성 강화연구와 무선 해킹과 방어 기술 발전에 초석이 될 것이다.

• Journal of Korean Association for Spatial Structures
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• v.19 no.2
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• pp.91-99
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• 2019

The push-out tests have been conducted on the specimens which consist of the steel beam with U-shape section and the continuous cap-type shear connector. Existing formulas for the elevation of shear connector capacity were investigated on the basis of test results. The shear capacities of continuous cap-type shear connectors distinctly declined as the diameters of side-hole in the shear connector increased. The rebars through side-hole for the transverse reinforcement improved the shear capacity of continuous cap-type connector by 20 to 30 percent. It was not feasible to obtain the appropriate capacity values of continuous cap-type shear connectors made of thin steel plate like those of in this study, using the existing formulas. The new formula for reflecting the shear strength of penetrative bars was proposed based on the shear equation of Eurocode 4. The slip capacities of continuous cap-type shear connectors were shown to exceed the limit value of 6mm for the sufficiently ductile behavior.

• Journal of Broadcast Engineering
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• v.24 no.4
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• pp.613-622
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• 2019

A differential codebook design method using wireless channel's temporal correlation is proposed over closed loop multiple-input single-output (MISO) system. The single layer codewords in a codebook are selected among a set of phase elements. In the conventional codeword selection rule, codewords are assumed to be on a spherical cap and sine formula was used. In this paper, however, a new method using Pythagoras formula is employed to simplify computational complexity. Also, an adaptive differential codebook selection is adopted to enhance performance. Monte-Carlo simulations demonstrate that the proposed codebook is superior to the conventional ones.

• Journal of Engineering Education Research
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• v.22 no.2
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• pp.61-70
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• 2019

This paper deals with a 'Designeer' education program that has a specific objective of educating design to undergraduate students in mechanical engineering with the aim of enhancing their ability of collaboration with designers when they are going to work in the field after graduation. The entire curriculum of the Designeer education program is introduced first, the end of which two-semester Capstone Design Courses for senior students is offered to let them practice all the knowledge and skills in a project-based learning environment. Learning specific matters such as sketching & visual thinking, prototyping and user experience design is one thing and practicing those knowledge and skills into a Capstone Design project is another. At this point, design thinking process needs to be in place to give students a foresight of one-year journey and to ensure that they will produce a desirable, feasible and viable product at the end of the year when they define the right problem at the beginning. Their frustrations and discoveries while applying design thinking throughout the year is explained by taking an example of a Robot Vacuum Cleaner design project. Finally, we provide real examples of effective methods to practice divergent and convergent phases.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.58-65
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• 2018

The life span of the porcelain insulator was made to be 30 years, but currently many of the 154kV NGK porcelain insulators using in Korea are found to have passed the production life. Accidents caused by aged mechanical breakdown can lead to disruption of power supply in some areas, large economic losses, and casualties. Therefore, ultrasonic method, which is one of the non - destructive test methods, is applied as a method for evaluating the integrity of porcelain insulators. In this study, the experiment on the interface of cap was conducted and the difference between the energy difference and the attenuation coefficient of the reflected wave was derived according to the interface state of the steel - cement. The results of this study are expected to be used as the basic data of the ultrasonic testing to evaluate the interface condition of the porcelain insulator cap.

• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.394-401
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• 2020

Purpose: The present study is an analysis of the extents of class satisfaction of college students who had applied the design thinking technique to capstone design class. Methods: The experimental method involved an analysis of 122 cases of data where advance and post replies were performed for the subject by students who had applied the design thinking technique and students who had not. The students involved had attended the capstone design class as a junior in the Department of Dental Technology at D University. Results: In the satisfaction with performance process of the capstone design class, five questions among nine had a high positive rating, while all eight questions on the satisfaction with performance methods had a high negative rating. Among ten questions on subjective learning outcomes, six showed a high positive rating. After the application of the design thinking class method, all mean values of the group with the application were higher than the group with no application in satisfaction with performance process, satisfaction with performance method, and subjective class outcomes. Hence, the design thinking class did have positive effects on the students' improvement of class. Conclusion: Based on the results of the study, it is implied that the considerations about diverse class composition methods and operation methods capable of improving the students' satisfaction are needed for efficient operation of the capstone design class.