• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.1
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• pp.39-43
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• 2021

In the case of ZnO:Al thin films, it is the best material that can replace ITO that is mainly used as a transparent electrode in electronic devices such as solar cells and flat-panel displays. In this study, ZnO:Al films were fabricated by using the RF dual magnetron sputtering method at various substrate temperatures. As the substrate temperature increased, the crystallinity of the ZnO:Al thin films was improved, and the electrical conductivity and electrical properties of the thin film improved owing to the increase in grain size. In addition, the surface roughness of the ZnO:Al thin films increased due to changes in the surface and density of the thin films. Moreover, the substrate temperature increased the density of thin films and improved their transmittance. To be applied to solar cells and other several electronic devices in the future, the hardness and adhesion properties of the thin film improve as the substrate temperature increases.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.525-530
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• 2023

Stretchable piezoelectric energy harvester (S-PEHs) based on composite materials are considered one of the potential candidates for realizing wearable self-powered devices for smart clothing and electronic skin. However, low energy conversion performance and expensive stretchable electrodes are major bottlenecks hindering the development and application of S-PEHs. Here, we fabricated the S-PEH by adopting the piezoelectric composites with enhanced stress transfer properties and kirigami-patterned textile electrodes. The optimum contents of piezoelectric BaTiO₃ nanoparticles inside the carbon nanotube/ecoflex composite were selected as 30 wt% considering the trade-off between stretchability and energy harvesting performance of the device. The final S-PEH shows an output voltage and mechanical stability of ~5 V and ~3,000 cycles under repeated 150% of tensile strain, respectively. This work presents a cost-effective and scalable way to fabricate stretchable piezoelectric devices for self-powered wearable electronic systems.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.325-333
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• 2014

An ADS-B system, which is a critical technology in surveillance area of the CNS/ATM, can replace or compensate a conventional radar based surveillance system through the communications among aircrafts. An ADS-B ground system which is to use the ADS-B on the ground air traffic management system consists of various subsystem devices such as ground stations that communicate with the aircrafts, and ADS-B/TIS-B/FIS-B servers. The ADS-B ground system has a form of distributed system and is interconnected through the network. Therefore, a system which can monitor and control the status of the multiple subsystem devices of the ADS-B ground system is essential. In this paper, we designed and implemented a remote status monitor and control system for the ADS-B system that can monitor and control the subsystem devices of the ADS-B system in remote place via SNMP protocol.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.25-31
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• 2014

In this paper, a modified Alford loop antenna for on-body communication system is proposed. The proposed antenna operating in the ISM band is designed with consideration of human body effect. One of advantages of the Alford loop antenna structure is low-profile, however the Alford loop antenna is not suitable for on-body devices since it does not have a ground plane for other electronic part of on-body system and requires balanced feeding structure. To be embedded on on-body devices, the proposed antenna is design with the unbalanced feed structure and ground. The performance of the proposed antenna is simulated and measured when it is placed on the human body phantom to consider the effect of the human body. The proposed antenna a 10 dB return loss bandwidth over the ISM band and monopole-like radiation pattern with low-profile. The antenna has the surface of appropriate for on-body communication environment.

• Journal of Sensor Science and Technology
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• v.24 no.5
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• pp.319-325
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• 2015

While the conventional personal protective equipments (PPEs) covers a variety of devices and garments such as respirators, turnout gear, gloves, blankets and gas masks, several electronic devices such as personal alert safety system (PASS) and heads-up displays in the facepiece have become a part of firefighters personal protective equipments through past several years. Furthermore, more advanced electronic sensors including location traking sensor, thermal imaging caerma, toxic gas detectors, and even physiological monitoring sensors are being integrated into ensemble elements for better protection of firefighters from fire sites. Despite any electronic equipment placed on the firefighter must withstand environmental extremes and continue to properly function under any thermal conditions that firefighters routinely face, there are no specific criteria for these electronics to define functionability of these devices under given thermal conditions. Although manufacturers provide the specifications and performance guidelines for their products, their operation guidelines hardly match the real thermal conditions. Present study overviews firefighter's fatalities and thermal conditions that firefighters and their equipments face. Lastly, thermal packaging methods that we have developed and tested are introduced.

• Journal of Digital Convergence
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• v.17 no.4
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• pp.327-334
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• 2019

This study is a case study of couple counseling case applying Satir Empirical Growth Model to improve the communication and self - esteem of the sexual offenders who are attached to the electronic devices requested by the representative at the ${\bigcirc}{\bigcirc}$ Compliance Support Center. The counseling process was carried out in this center counseling room for 120 minutes from March to June 2017 once a week for 5 times in total. To validate the effects of this study, researchers and observer-centered techniques were used as subjective evaluations. Based on the results of the study, the following conclusions were obtained. The self - esteem and communication change of the subjects with sexual violence electronic devices were found to be positive. This suggests that there is a significant effect in suggesting the possibility of using the marital counseling in the practice of the correctional facility.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.5
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• pp.459-465
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• 2022

This paper reports a method to use a wireless sensor network deployed in the field to real-time monitor soil moisture, warning when the moisture level reaches a specific value, and wirelessly controlling an additional device (LED or water supply system, etc.). In addition, we report all processes related to wireless irrigation system, including field deployment of sensors, real-time monitoring using a smartphone, data calibration, and control of additional devices deployed in the field by smartphone. A commercially available open-source Internet of Things (IoT) platform, NodeMCU, was used, which was combined with a 9V battery, LED and soil humidity sensor to be integrated into a portable prototype. The IoT-based soil humidity sensor prototype deployed in the field was installed next to a tree for on-site demonstration for the measurement of soil humidity in real-time for about 30 hours, and the measured data was successfully transmitted to a smartphone via Wifi. The measurement data were automatically transmitted via e-mail in the form of a text file, stored on the web, followed by analyses and calibrations. The user can check the humidity of the soil real-time through a personal smartphone. When the humidity of a soil reached a specific value, an additional device, an LED device, placed in the field was successfully controlled through the smartphone. This LED can be easily replaced by other electronic devices such as water supplies, which can also be controlled by smartphones. These results show that farmers can not only monitor the condition of the field real-time through a sensor monitoring system manufactured simply at a low cost but also control additional devices such as irrigation facilities from a distance, thereby reducing unnecessary energy consumption and helping improve agricultural productivity.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.3
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• pp.10-17
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• 2024

This paper discusses Chip On Film (COF) technology, one of the key technologies in flexible packaging to enable miniaturization and flexibility of electronic devices. COF attaches Display Driver IC (DDI) directly to a flexible polyimide substrate, enabling lightweight and reduced thickness for high-resolution displays. COF technology is primarily used in high-performance display panels, such as organic light emitting diode (OLED) displays, and plays a key role in portable electronic devices, such as smartphones and wearable devices. This study analyzes the key components of COF and advances in bonding technology. In particular, the introduction of modern bonding techniques, such as thermo-compression bonding and thermo-sonic bonding, has led to significant improvements in bonding reliability and electrical performance. These bonding techniques enhance the mechanical stability of COF packages while maintaining high electrical connectivity in fine-pitch structures. This paper will discuss the future development of COF bonding technology and its challenges and explore its potential as a next-generation display and advanced packaging technology.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.2
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• pp.78-85
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• 2012

Low-Voltage power lines should equip surge protection devices which protect electronic equipments and human lives against lightning and abnormal voltages. Data transmission capacity of the power line is determined by frequency characteristics of the surge protective devices. To analyze the effects of surge protective devices on the data transmission performance, various combinations of installation methods are tested which include ZnO varistor elements that is compatible with class I, class II and class III. The result claims that ZnO varistor for class III is found to be one of the main factors that deteriorates the transmission performance. To overcome this problem a serial connection methed between Gap type SPD and ZnO varistor is proposed. With the proposed scheme, laboratory experimental results show that the data transmission performance can be improved up to 91.9[%] with proper SPD combination.

• Vacuum Magazine
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• v.3 no.1
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• pp.22-31
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• 2016

Although graphene has been considered as one of the promise materials for future logic devices due to extremely high mobility, its applications in electronics have been limited to a few cases such as a flexible interconnect, and RF devices. Furthermore, most of the studies on graphene devices reported unstable operations, claimed to be due to the poor quality of graphene. Nevertheless, recent studies showed that the electrical performance of graphene field effect transistor could be stabilized even with CVD graphene when well-established integration processes to control the interface of graphene were used. These results indicate that as in the case of silicon devices, a proper control of graphene interface is very important for the stable operation of graphene device as well as other 2D material based devices.