• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.35-41
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• 2021

A rotor is a crucial component in various mechanical assemblies. Additionally, high-speed and high-efficiency components are required in the automotive industry, manufacturing industry, and turbine systems. In particular, the failure of high-speed rotating bearings has catastrophic effects on auxiliary systems. Therefore, bearing reliability and fault diagnosis are essential for bearing maintenance. In this work, we performed failure mode and effect analysis on bearing rotors and determined that corrosion is the most critical failure type. Furthermore, we conducted experiments to extract vibration characteristic data and preprocess the vibration data through principle component analysis. Finally, we applied a machine learning algorithm called support vector machine to diagnose the failure and observed a classification performance of 98%.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.113-118
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• 2020

Recently, eco-friendly electric motorcycles have been considered to replace aging gasoline motorcycles to reduce the amount of suspended fine dust in air. However, existing rechargeable battery-powered electric motorcycles have been found unacceptable by users because of their many limitations, such as long charging time, short travel distance per charge, and low driving speed. To overcome the drawbacks of conventional electric motorcycles, this paper proposes an exchangeable battery-powered electric motorcycle and a new frame shape for housing the exchangeable battery. The proposed frame is similar to that of current electric motorcycles; however, the shape and position of the saddle support, battery, and controller mount section are redesigned. The safety of the presented frame is verified through static and dynamic analyses using ABAQUS. In particular, the dynamic analysis is conducted under the most extreme condition among the various operating situations, thus confirming the robustness of the proposed frame design.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.108-113
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• 2021

Recently, a new concept of a one-touch descending lifeline has been proposed to address the drawbacks of the conventional descending lifeline, which can be easily installed and quickly evacuated in the case of a fire emergency. All separate parts for escape are initially mounted in a box, and the link-type support is spread out of the window by pushing the handle attached to the box. In this study, the proposed double square linkage mechanism was redesigned, and its safety is verified by determining an appropriate moment of inertia of the link through finite element analysis using Abaqus. The shape and assembling method of the reel and speed controller were also modified such that the safety belt was simultaneously unfolded with link-type support. Finally, the feasibility of the proposed one-touch all-in-one descending lifeline was confirmed through fabrication.

• Journal of the KSME
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• v.52 no.11
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• pp.43-47
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• 2012

이 글에서는 두산인프라코어(주)를 중심으로 15개 국내외 기관이 참여하여 토목 및 전자 그리고 기계기술의 융합을 통해 개발한 세계 최초의 지능형 무인 굴착 시스템을 소개하고자 한다.

• Journal of Drive and Control
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• v.21 no.1
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• pp.77-80
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• 2024

• Journal of Drive and Control
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• v.21 no.1
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• pp.81-85
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• 2024

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.165-170
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• 2021

Machine learning has recently been applied to research in most areas. This is because the results of machine learning are not determined, but the learning of input data creates the objective function, which enables the determination of new data. In addition, the increase in accumulated data affects the accuracy of machine learning results. The data collected here is an important factor in machine learning. The proposed system is a convergence system of cloud systems and local fog systems for service delivery. Thus, the cloud system provides machine learning and infrastructure for services, while the fog system is located in the middle of the cloud and the user to collect and refine data. The data for this application shall be based on the Sensitive data generated by smart devices. The machine learning technique applied to this system uses SVM algorithm for classification and RNN algorithm for status recognition.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.178-183
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• 2021

This paper describes a dynamic spectroscopic ellipsometry based on dual-wavelength calibration. DSE provides ellipsometric parameters at rates above 20 Hz, but the interferometer's sensitivity to temperature makes it difficult for that proposed system to maintain stable 𝜟k over long periods of time. To solve this problem, we set up an additional path in the DSE to perform simulations of the polarization phase calibration method using dual wavelengths. Through simulation, we were able to eliminate most of the polarization phase error and maintain a stable 𝜟k in the long-term stability experiment for 10 hours. This is the result that the 𝜟k stability of the proposed system is improved tens of times compared to the existing system.

• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.90-95
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• 2023

We describe an optimal alignment method for improving accuracy of dynamic spectroscopic polarimeter based on monolithic polarizing interferometer. The dynamic spectroscopic polarimeter enables real-time measurements of spectral ellipsometric parameters by using a spectral carrier frequency concept. However, the non-polarizing beam splitter used in the monolithic polarizing interferometer cannot maintain the polarization state perfectly due to phase retardation caused by optical anisotropic characteristics of the non-polarizing beam splitter, resulting in degraded measurement accuracy. The effect of the beam splitter can be minimized through optimal alignment of the polarizers used in the polarizing interferometer and the analyzer. We demonstrate how much the proposed alignment method can enhance the measurement accuracy by comparing with previous alignment approach.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.809-810
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• 2023

도서관 자동화 시스템 개발로 이용자가 책을 직접 찾지 않고, 대출하고자 하는 책을 PC에 입력하면 자율주행으로 책이 있는 서가로 이동, 딥러닝 기반의 로봇팔로 책을 잡고 기존 위치로 복귀하여 자동으로 대출과 운반이 가능한 로봇의 시스템을 제안한다.