• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.19-25
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• 2023

With an attempt to investigate the correlation between the internal pressure distribution of slit nozzle and the thickness uniformity of slot-coated thin films, we have performed computational fluid dynamics (CFD) simulations of slit nozzles and slot coating of high-viscosity (4,800 cPs) polydimethylsiloxane (PDMS) using a gantry slot-die coater. We have calculated the coefficient of variation (CV) to quantify the pressure and velocity distributions inside the slit nozzle and the thickness non-uniformity of slot-coated PDMS films. The pressure distribution inside the cavity and the velocity distribution at the outlet are analyzed by varying the shim thickness and flow rate. We have shown that the cavity pressure uniformity and film thickness uniformity are enhanced by reducing the shim thickness. It is addressed that the CV value of the cavity pressure that can ensure the thickness non-uniformity of less than 5% is equal to and less than 1%, which is achievable with the shim thickness of 150 ㎛. It is also found that as the flow rate increases, the average cavity pressure is increased with the CV value of the pressure unchanged and the maximum coating speed is increased. As the shim thickness is reduced, however, the maximum coating speed and flow rate decrease. The highly uniform PDMS films shows the tensile strain as high as 180%, which can be used as a stretchable substrate.

• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.32-37
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• 2023

For the potential applications in large-area OLED lightings, hydrogen fuel cells, and secondary batteries, we have performed an intermittent coating of high-viscosity polydimethylsiloxane using roll-to-roll slot die coater. During intermittent coating, dead zones inevitably appear where the thickness of PDMS patch films becomes non-uniform, especially at the leading/trailing edge. To reduce it, we have coated the PDMS patches by varying the process parameters such as the installation angle of the slot die head, coating speed, and patch interval. It is observed that the PDMS solution flows down and thus the thickness profile is non-uniform for horizonal intermittent coating, whereas the PDMS solution remaining on the head lip causes an increase in the PDMS thickness at the leading/trailing edges for vertical intermittent coating when the coating velocity is low. As the coating speed increases, however, the dead zone is shown to be reduced. It is addressed that the overall dead zone (the dead zone at the leading edge + the dead zone at the trailing edge) is smaller with horizontal intermittent coating than with vertical intermittent coating.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.3
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• pp.555-560
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• 2018

In this paper, we focus on the study of educational contents using real vehicle based electric vehicle diagnosis system. To understand the electric vehicle, we describe the driving modes and operating principles of the core components and electric vehicles that make up the electric vehicles. In addition, we implemented a diagnostic system for analyzing the characteristics of the electric vehicle test bed and analyzed the characteristics of the vehicle based on the driving mode.

• Journal of Software Assessment and Valuation
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• v.17 no.1
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• pp.93-99
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• 2021

The demand for online education has rapidly increased due to the influence of COVID-19. One of the biggest challenges in engineering education is how to efficiently conduct experiments online. In this paper, for the virtual experimental system for microcontroller application that is essential for education in the field of electrical, electronic, and control engineering, we described the microcontroller functional modeling and implementation with Java language. The usefulness of the developed microcontroller module has been verified through educational field application.

• Journal of Engineering Education Research
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• v.24 no.4
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• pp.61-74
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• 2021

The purpose of this study is to provide a direction for domestic engineering education research by analyzing the research trends of JEE(Journal of Engineering Education). The results of analyzing research trends regarding research topics, research objects and research methods are as follows. First, by research topic, 'Diffusion of Educational Innovation' was found to have the highest proportion with 52 articles(21%). Second, by research objects, 'university students' showed the highest proportion with 148 articles(53.6%). Third, by research method (large category), 'quantitative research' had the highest proportion with 132 articles(53.2%). By research method (medium category), 'survey research' had the highest proportion with 129 articles(33.5%). Based on the results of this study, future engineering education research should be conducted to contribute to holistic development through diversification of research topics, methods, and objects.

• 한국정보교육학회:학술대회논문집
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• 2010.01a
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• pp.171-174
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• 2010

디지털 강국을 선도하기 위해서는 초등학교에서부터 정보통신 관련 교육적 경험을 제공하는 것이 필요시 된다. 본 연구에서는 초등학생의 인지발달 수준에 부합하고 전기, 전자 통신 학습에 효과적인 교구인 디키를 교과통합 및 재량활동에 적용하고 학습자의 반응을 분석하여 교육적 효과를 살펴보았다. 학습초기에 생소한 부품들로 학습곤란을 경험하였지만 교육이 진행될수록 기존의 습득한 지식과 기능을 바탕으로 지식을 재구조하여 창의적 표현 및 문제해결활동에 활용하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.861-863
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• 2014

Fingerprinting technique exists at the position assumption system for the service of indoor location-based. However, there is a problem it takes a long time to build fingerprinting map. We need to verify that received signal of WAP(wireless access point) is similar at all times in a similar space in order to solve these problems. This paper proposes a plan that is able to build fingerprinting map by using the received signal data of WAP. To do this, change the positon of WAP in the same space, It is confirmed the process of change of the RSSI corresponding to the distance. We also confirmed that the RSSI collected from elsewhere in the space a similar change in the same manner.

• Journal of Advanced Navigation Technology
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• v.27 no.2
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• pp.203-208
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• 2023

In this study, we propose a method to improve the precision of contact resistance measurement circuits using constant current method and voltage drop method, and implement a dashboard that monitors the measured data of contact resistance measurement systems through MQTT broker server. The contact resistance measurement system measures the resistance value and transmits the measured value to the MQTT broker server using wireless communications. This developed dashboard uses Node-RED and Node-RED-Dashboard to receive the resistance values of up to four contact resistance measurement systems and show them to user's monitor screen. Users can manage multiple measurement data using a single dashboard and easily interface with other devices through the MQTT broker server. Through the experimental results from real data measurements, the relative standard deviation about precision is improved to average 40.37% and maximum 64.73% respectively.

• Journal of the Semiconductor & Display Technology
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• v.22 no.2
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• pp.11-16
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• 2023

EtherCAT is an Ethernet-based fieldbus system standardized in IEC 61158 and SEMI, and widely used in the fields of factory automation, semiconductor equipment and robotics. In this paper, without operating system, we have implemented an EtherCAT master with an open source EtherCAT master stack SOEM on STM32 Nucleo-144 board with an STM32F767 microcontroller. And its jitter performance has been evaluated at the output of the network port to include all the effects of the entire system in the results. The results show that the implemented EtherCAT master has precise control performance for control frequencies from 1KHz to 8KHz and relatively superior jitter performance compared to the EtherCAT masters with real-time patched Linux operating system.

• Journal of the Semiconductor & Display Technology
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• v.23 no.2
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• pp.55-59
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• 2024

Plasma Enhanced Chemical Vapor Deposition (PE-CVD) is a widely used technology in semiconductor manufacturing for thin film deposition. The implementation of wafer guide rings in PE-CVD processes is crucial for enhancing efficiency and product quality by ensuring uniform deposition around wafer edges and reducing particle generation. On the other hand, to prevent overall temperature non-uniformity and degradation of thin film quality within the chamber, it is essential to consider various parameters comprehensively. In this study, after applying the wafer guide rings, temperature variations and fluid flow changes were simulated. Additionally, by simulating the temperature and flow changes when applied to the PE-CVD chamber, this paper discusses the importance of optimizing variables within the entire chamber.