• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1275-1282
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• 2012

This paper proposes the 16-channel LED Driver IC for Full color LED display system. The proposed LED driver IC in this paper can draw current independent of temperature and supply voltage in each channel. Current flow in the channel is configurable via an external resistor. LED brightness is adjusted by 12-Bit PWM(Pulse Width Modulation) and 8-Bit DC(Dot Correction). A real-time monitoring of IC temperature ($130^{\circ}C/150^{\circ}C$) and LED status (open/short) is provided by LED driver IC and the user can receive warning and get information on problems. A 16-channel LED driver IC is produced using 0.35 um BCD process and the size is $2.5mm{\times}2.5mm$. In this paper, channel current characteristic and channel current control function were measured in order to verify am embodied 16-channel LED driver IC by producing a single IC test board.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.555-562
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• 2007

In order to display Bayer input stream received from CMOS image sensor to the display device, image signal processing must be performed. That is, the hardware performing the image signal processing for Bayer data is called ISP(Image Signal Processor). We can see real image through ISP processing. ISP executes functionalities for gamma correction, interpolation, color space conversion, image effect, image scale, AWB, AE and AF. In this paper, we obtained the optimum algorithm through software verification of ISP module for CMOS camera image sensor and described using VHDL and verified in ModelSim6.0a simulator. Also we downloaded into Xilinx XCV-1000e for the designed ISP module and completed the board level verification using PCI interface.

• Journal of the Semiconductor & Display Technology
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• v.20 no.2
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• pp.126-130
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• 2021

The ball grid array is one of the packaging methods that used in high density printed circuit board. Solder void defects caused by voids in the solder ball during the BGA process do not directly affect the reliability of the product, but it may accelerate the aging of the device on the PCB layer or interface surface depending on its size or location. Void inspection is important because it is related in yields with products. The most important process in the optical inspection of solder void is the segmentation process of solder and void. However, there are several segmentation algorithms for the vision inspection, it is impossible to inspect all of images ideally. When X-Ray images with poor contrast and high level of noise become difficult to perform image processing for vision inspection in terms of software programming. This paper suggests the solution to deal with the suggested problem by means of using Mask R-CNN instead of digital image processing algorithm. Mask R-CNN model can be trained with images pre-processed to increase contrast or alleviate noises. With this process, it provides more efficient system about complex object segmentation than conventional system.

• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.168-173
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• 2022

As the function of a product is advanced and the process is refined, the yield in the fine manufacturing process becomes an important variable that determines the cost and quality of the product. Since a fine manufacturing process generally produces a product through many steps, it is difficult to find which process or equipment has a defect, and thus it is practically difficult to ensure a high yield. This paper presents the system architecture of how to build a smart manufacturing system to analyze the big data of the manufacturing plant, and the equipment factor analysis methodology to increase the yield of products in the smart manufacturing system. In order to improve the yield of the product, it is necessary to analyze the defect factor that causes the low yield among the numerous factors of the equipment, and find and manage the equipment factor that affects the defect factor. This study analyzed the key factors of abnormal equipment that affect the yield of products in the manufacturing process using the data mining technique. Eventually, a methodology for finding key factors of abnormal equipment that directly affect the yield of products in smart manufacturing systems is presented. The methodology presented in this study was applied to the actual manufacturing plant to confirm the effect of key factors of important facilities on yield.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.217-221
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• 2012

As a part of basic research to improve screen quality, which deteriorates when strain occurs within optical sheets in LCD modules for laptop computers, a measurement system is needed to analyze the influence of heat and moisture, which are the main factors causing the strain. It is assumed that the existence of an air gap less of than 0.5 mm inside the LCD module causes humid air from outside to permeate through the module. To investigate this phenomenon, in this study a thin printed circuit board (PCB) of compact sensors that measure temperature and humidity is inserted into LCD modules, and thus, the changes in temperature and humidity can be analyzed in real time. The results can be used as basic data for simulation of the deformation behavior and structural design of LCD modules in the future.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.3
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• pp.310-321
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• 2019

Objectives: The purpose of this study was to investigate types and characteristics of chemical substances used in LCD(Liquid crystal display) panel manufacturing process. Methods: The LCD panel manufacturing process is divided into the fabrication(fab) process and module process. The use of chemical substances by process was investigated at four fab processes and two module processes at two domestic TFT-LCD(Thin film transistor-Liquid crystal display) panel manufacturing sites. Results: LCD panels are manufactured through various unit processes such as sputtering, chemical vapor deposition(CVD), etching, and photolithography, and a range of chemicals are used in each process. Metal target materials including copper, aluminum, and indium tin oxide are used in the sputtering process, and gaseous materials such as phosphine, silane, and chlorine are used in CVD and dry etching processes. Inorganic acids such as hydrofluoric acid, nitric acid and sulfuric acid are used in wet etching process, and photoresist and developer are used in photolithography process. Chemical substances for the alignment of liquid crystal, such as polyimides, liquid crystals, and sealants are used in a liquid crystal process. Adhesives and hardeners for adhesion of driver IC and printed circuit board(PCB) to the LCD panel are used in the module process. Conclusions: LCD panels are produced through dozens of unit processes using various types of chemical substances in clean room facilities. Hazardous substances such as organic solvents, reactive gases, irritants, and toxic substances are used in the manufacturing processes, but periodic workplace monitoring applies only to certain chemical substances by law. Therefore, efforts should be made to minimize worker exposure to chemical substances used in LCD panel manufacturing process.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.525-533
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• 2017

Objective: The aim of this study is to investigate maritime officers' strategies to avoid the ship collision in crossing situations. Background: In a situation where there is a risk of collision between two ships, maritime officers can change the direction and speed of the own-ship to avoid the collision. They have four options to select; adjusting the speed only, the direction only, both the speed and direction at the same time and no action. Research questions were whether the strategy they are using differs according to the shipboard experience of maritime officers and the representation method of ARPA (automatic radar plotting aid) - radar graphic information. Method: Participants were 12. Six of them had more than 3 years of onboard experience, while the others were 4th grade students at Korea Maritime and Ocean University. For each participant, 32 ship encounter situations were provided with ARPA-radar information. 16 situations were presented by the north-up display and 16 situations were presented by the track-up display. Participants were asked to decide how to move the own-ship to avoid the ship collision for each case. Results: Most participants attempted to avoid the collision by adjusting the direction of the ship, representing an average of 22.4 times in 32 judgment trials (about 70%). Participants who did not have experience on board were more likely to control speed and direction at the same time than participants with onboard experience. Participants with onboard experience were more likely to control the direction of the ship only. On the other hand, although the same ARPA Information was provided to the participants, the participants in many cases made different judgments depending on the method of information representation; track-up display and north-up display. It was only 25% that the participants made the same judgment under the same collision situations. Participants with onboard experience did make the same judgment more than participants with no onboard experience. Conclusion: In marine collision situations, maritime officers tend to avoid collisions by adjusting only the direction of their ships, and this tendency is more pronounced among maritime officers with onboard experience. The effect of the method of information representation on their judgment was not significant. Application: The results of this research might help to train maritime officers for safe navigation and to design a collision avoidance support system.

• English Language & Literature Teaching
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• v.17 no.3
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• pp.177-194
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• 2011

This study examines the use of discourse markers in cross-cultural communication between EFL learners in an e-learning environment. The study analyzes the use of discourse markers in a corpus of an interactive web with a bulletin board system through which college students of English at Japanese and Korean universities interacted with each other discussing the topics of local and global issues. It compares the use of discourse markers in the learners' corpus to that of a native English speakers' corpus. The results indicate that discourse markers are useful interactional devices to structure and organize discourse. EFL learners are found to display more frequent use of referentially and cognitively functional discourse markers and a relatively rare use of other markers. Native speakers are found to use a wider variety of discourse markers for different functions. Suggestions are made for using computer corpora in understanding EFL learners' language difficulties and helping them become more interactionally competent speakers.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.529-532
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• 2005

In this paper, we propose a motion picture processor for CSTN LCD. In order to eliminate flicker phenomenon, the proposed processor suggests a new driving scheme, SFP(Subgroup Frame Pattern). We use an input image compression methode from RGB(:8:8;8) to RGB(5:6:5) to improve quality of the image and apply the image to CSTN Module. The proposed hardware architecture has been implemented and verified using a FPGA on prototype board. The proposed Algorithm provide a lower computational complexity. Therefore the processor can be used in the display devices such as PDA, mobile phone and PMP(Portable Multimedia Player).

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.849-852
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• 2001

본 눈문에서는 뒤틀림, 응력, 압력[1], 토크, 가속도 등의 물리적인 동적 현상을 측정하여 수집된 데이터를 처리하기 위한 신호처리(Signal Processins) 기능이 결합되어 넓은 용도로 활용할 수 있는 센서 신호 수집 시스템을 구현하였다. 구현된 시스템은 data acquisition board 의 하드웨어와 소프트웨어로 나누어 볼 수 있다. 하드웨어의 구성은 아날로그부, 디지털부, 그리고 시스템 인터페이스 처리부로 되어 있다. 아날로그부에서는 센서신호를 받아서, PGA (Programmable Gain Amplifier)[2]와 Op-Amp를 사용하여 signal conditioning 처리하여 8차 Lowpass Filter 로 보낸다. Filtering 된 신호는 ADC (Analog to Digital Converter) 가 내장되어 있는 PIC(3) microcontroller로 보내져 AD변환과 디지털 신호 처리를 한다. 처리된 신호는 RS232 인터페이스를 통해 호스트 컴퓨터로 보내 사용자가 분석할 수 있도록 한다. 또한 LCD display 실시간으로 확인, 분석할 수 있으며 동시에analog output에서 센서신호의 특징을 분석 할 수 있도록 한다.