• Journal of Conservation Science
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• v.37 no.3
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• pp.255-269
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• 2021

A vast amount of materials-such as prints, woodblock prints, manuscripts, old novels, and letters-written in old Korean and using old grammar and/or obsolete characters, are collected in many institutions, including the Jangseogak at the Academy of Korean Studies. Digitization of these texts has required a prolonged manual inputting process. Individual researchers, who majored in old Korean, have read and typed the characters into electronic documents, which depends upon individual skill, effort, and approach, and is particularly limiting because none can be significantly increased. To date, only a small proportion of the old Korean document collections, currently kept in storage, have been digitized and made available to the public. Even the electronic formats of the texts prove difficult to displaying correctly, due to the incompatibility between the old Korean characters and the character set on today's electronic devices. To improve the techniques and efficiency of digitizing old Korean texts, it is necessary to develop optical character recognition (OCR), which will analyze images of old Korean documents, as well as input, display, and storage methods.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.835-844
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• 2021

In this paper, a power facility communication control device was designed to autonomously determine and separate the fault section through communication between power facilities in the smart grid distribution system. In the power facility communication control device, the control module was designed as a DSP to measure three-phase voltage and current, and the communication module was designed as an embedded-based Raspberry Pi to determine the fault section and realize the fault section separation through communication between power facilities. Communication between DSP and Raspberry Pi was designed by SPI communication, and communication between Raspberry Pi was designed based on Wi-Fi. Finally, a performance evaluation system based on three power facility communication control devices was built, and simulation verification was conducted for various fault events that may occur on the distribution line. As a result of the test evaluation, it was possible to confirm the effectiveness of the design methodology of the communication control device by showing the required response of the communication control device to all test cases.

• Progress in Superconductivity and Cryogenics
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• v.23 no.2
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• pp.6-9
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• 2021

Heterostructures fabricated by various combinations of van der Waals (vdW) materials enable us to investigate disorder-free physical properties and realize novel functional devices. Superconducting vdW junctions have attracted a lot of attention because of its simple structure without a barrier layer. In superconducting vdW junction, without extra fabrication effort, a natural barrier can be formed, whose character is sensitive to distance and angle of lattice between two superconducting vdW materials. Using high-quality single crystals and the dry transfer technique, we fabricated the vertically stacked NbSe₂/NbSe₂ and FeSe/FeSe vdW junctions and investigated their Josephson junction properties. We found that in the FeSe junctions, Josephson coupling is extremely sensitive to the fabrication conditions, in contrast to the NbSe₂ junctions. We attributed this distinct character of the FeSe junctions to surface instability and small Fermi surface of FeSe.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.4
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• pp.119-126
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• 2006

In order to improve voters' reliability in electronic voting system, voter verifiable receipt technique is being actively researched. Since the receipt should be verifiable not only inside but also outside a polling place, it satisfies the requirements, individual verifiability and receipt-freeness. In the previous researches, there are some problems that special paper and printer is necessary or frequent monitoring is needed to confirm the voting machine's trustworthiness. In this paper, we propose a new receipt issuing scheme. Our scheme does not require any special equipments such as special paper and printer or optical scanner. In addition to that it does not require voters to trust any devices in the polling station and there is no need of frequent observations to the voting machines.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.101-108
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• 2021

This paper builds a real-time home security system based on the OneNet cloud platform to control the status of the house through a smartphone. The system consists of a local part and a cloud part. The local part has I/O devices, router and Raspberry Pi (RPi) that collects and monitors sensor data and sends the data to the cloud, and the Flask web server is implemented on a Rasberry Pi. When a user is at home, the user can access the Flask web server to obtain the data directly. The cloud part is OneNet in China Mobile, which provides remote access service. The hybrid App is designed to provide the interaction between users and the home security system in the smartphone, and the EDP and RTSP protocol is implemented to transmit data and video stream. Experimental results show that users can receive sensor data and warning text message through the smartphone and monitor, and control home status through OneNet cloud.

• Journal of IKEEE
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• v.25 no.4
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• pp.689-696
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• 2021

In this paper, in order to apply Prognostics and Health Management(PHM) to an electronic system or circuit, a circuit capable of detecting and predicting defect characteristics inside the system or circuit is implemented, and the results are described. In the previous study, we demonstrated that the frequency of the amplitude of S-parameter changed as the circuit defect progressed. These characteristics were measured by network analyser. but in this study, even if the same defect detection method is used, a circuit is proposed to check the progress of the defect, the remaining time, and the occurrence of the defect without large measurement devices. The circuit is designed to detect the change in impedance that generates changes of S-parameter, and it is verified through simulation using the measurement results of Bond-wires.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.641-648
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• 2023

Recently, the rapid growth of artificial intelligence among the 4th industrial revolution has progressed based on the performance improvement of semiconductor, and circuit integration. According to transistors, which help operation of internal electronic devices and equipment that have been progressed to be more complicated and miniaturized, the control of heat generation and improvement of heat dissipation efficiency have emerged as new performance indicators. The DUT(Device Under Test) Shell is equipment which detects malfunction transistor by evaluating the durability of transistor through heat dissipation in a state where the power is cut off at an arbitrary heating point applying the rating current to inspect the transistor. Since the DUT shell can test more transistor at the same time according to the heat dissipation structure inside the equipment, the heat dissipation efficiency has a direct relationship with the malfunction transistor detection efficiency. Thus, in this paper, we propose various method for PCB configuration structure to optimize heat dissipation of DUT shell and we also propose various transformation and thermal analysis of optimal DUT shell using computational fluid dynamics.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.723-730
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• 2023

Due to the recent development of battery technology, various types of means of transportation such as electric kickboards, Segways, and electric bicycles have emerged, which can be defined as Personal Mobility. In this paper, as the incidence of safety accidents increases due to the increase in the number of users of Personal Mobility, safety helmet devices that strengthen safety capabilities and peripheral recognition functions were studied. In order for the helmet to send a safety signal, Arduino was used as a base to set the value of the sensor according to changes in distance and angle using the ultrasonic sensor to minimize errors and ensure smooth recognition. In addition, a gyro sensor was used to turn on the direction indicator according to each slope. Using a CDS sensor, the LED is designed to turn on when it goes below 150 lux at night. Finally, it is possible to check whether a helmet is worn within 5cm, and when driving at an average speed, the direction indicator light is turned on at 10 degrees, and the LED is turned on at less than 150 lux.

• 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 Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.6
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• pp.633-637
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• 2023

Recently, with the development of the smart device market, the integration of high-functional devices has increased the heat density, causing overload of the device, and resulting in various problems such as shortened lifespan, performance degradation, and failure. Therefore, research on heat dissipation materials is being actively conducted to realize next-generation electronic products. The heat dissipation material is characterized in that it is easy to dissipate heat due to its high thermal conductivity and minimizes leakage current flowing through the heat dissipation material due to its low electrical conductivity. In this study, flower-shaped Al₂O₃ and BN composites were engineered with a simple hydrothermal synthesis approach, and their thermal conductivity characteristics were compared and evaluated for each synthesis condition for the application to a heat dissipation material. Spherical BN and flower-shaped Al₂O₃ were easily obtained, and SEM/EDS analyses confirmed the uniform presence of BN between the Al₂O₃, and it can be expected that these shapes can affect the thermal conductivity.