• 대한건축학회연합논문집
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• 제20권6호
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• pp.47-54
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• 2018

The purpose of this study is to verify the long - range measurement performance for practical field application of VDMS. The reliability of the VDMS was verified by comparison with the existing monitoring sensor, GPS, Accelerometer and LDS. It showed the ability to accurately measure the dynamic displacement by tracking a motion of free vibration of target. And using the PSD function of measured data, the results in the frequency domain were also analyzed. We judged that VDMS is able to identify the higher system mode and has sufficient reliability. Based on the reliability verification, we conducted tests for long-distance applicability for actual application of VDMS. The distance from the stationary target model structure was increased by 50m interval, and the maximum distance was set to 400m. From the distance of 150m, the image obtained by the commercial camcorder has an error in the analysis, so the measured displacement comparison was performed between the LDS and the refractor telescope measurement results. In the measurement results of the displacement area of VDMS, the data validity was deteriorated due to the data shift by the external force and the quality degradation of the enlarged image. However, even under the condition that the effectiveness of the displacement measurement data of VDMS is low, the first mode characteristic included in the free vibration of the object is clearly measured. If the influence from the external environment is controlled and stable data is collected, It is judged that reliability of long-distance VDMS can be secured.

• 한국전기전자재료학회논문지
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• 제32권5호
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• pp.371-375
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• 2019

Developing a thin-film transistor with characteristics such as a large area, high mobility, and high reliability are key elements required for the next generation on displays. In this paper, we have investigated the research trends related to improving the reliability of oxide-semiconductor-based thin-film transistors, which are the primary focus of study in the field of optical displays. It has been reported that thermal treatment in a high-pressure oxygen atmosphere reduces the threshold voltage shift from -7.1 V to -1.9 V under NBIS. Additionally, a device with a $SiO_2/Si_3N_4$ dual-structure has a lower threshold voltage (-0.82 V) under NBIS than a single-gate-insulator-based device (-11.6 V). The dual channel structure with different oxygen partial pressures was also confirmed to have a stable threshold voltage under NBIS. These can be considered for further study to improve the NBIS problem.

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권4호
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• pp.331-342
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• 2011

The transmission of tracked vehicles performs complex functions as steering, shifting, braking, etc. and the system level life time has been a key influenced by the number of sub-parts like as gear assembly, torque converter, clutches, bearings and so on. In particular, the mechanical type steering system in tracked vehicle has impact shock torques in steering shift and those kind of shock torques can effect on the durability of many sub-parts in power train system. The field failure modes of gear assembly, steering assembly and the bearings of output shaft appear as a very complex phenomenon. In this study, the actual failure, which may occur in field, of the transmission was investigated comprehensively and that the endurance test on the resulting output shaft bearing failure analysis and life assessment was performed. Life time test method used in this study, developed for the purpose of the internal usage, and under these testing techniques the impact of the each bearing damage, which used in tracked vehicle transmission left / right outputs of different structures, was analyzed.

• 한국통신학회논문지
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• 제30권2A호
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• pp.66-79
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• 2005

본 논문에서는 스마트 무인항공기의 데이터 링크의 신뢰성 향상을 위하여 그것을 구성하는 RF 송수신 시스템의 성능 분석 및 통신링크 분석을 수행하였다. 시스템 분석은 데이터 링크의 개발 사양서 및 사용되는 부품의 data sheet를 참조하여 시스템 시뮬레이션 툴인 Agilent EEsof ADS(Advanced Design System)을 이용하여 수행하였고, 통신링크 분석은 스마트 무인항공기 운용 환경에 맞는 다양한 전파 모델들을 이용하여 분석하였다. 그 결과, 시뮬레이션 결과와 개발 사양서에서 나타난 문제점들을 제시하였고, 통신링크 분석을 통해 나타난 문제점 및 시스템 설계를 위한 고려사항에 대하여 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.793-796
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• 2003

The electronics of a mobile robot ill nuclear facilities is required to satisfied the reliability to sustain survival in its radiation environment. To know how much radiation the robot has been encountered to replace sensitive electronic parts, a dosimeter to measure total accumulated dose is necessary. Among many radiation dosimeters or detectors, semiconductor radiation sensors have advantages in terms of power requirements and their sires over conventional detectors. This paper describes the use of the radiation-induced threshold voltage change of a commercial power pMOSFET as an accumulated radiation dose monitoring mean and that of the photo-current of a commercial PIN Diode as a dose-rate measurement mean. Commercial p-type power MOSFETs and PIN Diodes were tested in a Co-60 gamma irradiation facility to see their capabilities as radiation sensors. We found an inexpensive commercial power pMOSFET that shows good linearity in their threshold voltage shift with radiation dose and a PIN diode that shows good linearity in its photo-current change with dose-rate. According to these findings, a radiation hardened hybrid electronic radiation dosimeter for nuclear robots has been developed for the first time. This small hybrid dosimeter has also an advantage in the point of view of reliability improvement by using a diversity concept.

• 한국산업정보학회논문지
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• 제7권4호
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• pp.46-52
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• 2002

기업의 경영범위가 확대되고 경영패러다임이 글로벌 경영으로 전환되면서 기업의 가치평가도 제품 및 서비스 위주 평가뿐만 아니라 작업장내에서 발생하는 각종 사고에 대한 평가까지도 포함시키는 포괄적인 기업경영평가로 확대되고 있다. 그래서 기업들도 안전보건에 대한 관리에서 실패할 경우, 기업의 이미지 저하는 물론 사고처리비용이 많이 들기 때문에 각 기업은 안전보건에 대해 지속적인 투자와 많은 관심을 가져야 한다. 따라서 본 연구에서는 산업현장에서 안전관리를 하는데 있어서 문제점을 살펴보고, 그리고 재해예방전문기관의 설립 전과 설립 후에 대한 재해통계자료를 Duane의 신뢰성 성장모델을 이용하여 분석해 보고, 모델의 적합성을 검증해 보고자 한다. 이러한 분석을 위해서 재해발생 수는 포아송 분포로, 그리고 분포의 평균값은 시간에 따라 변화하는 NHPP로 가정하였다.

• International journal of advanced smart convergence
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• 제12권2호
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• pp.47-55
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• 2023

The automotive industry is undergoing a paradigm shift due to the convergence of IT and rapid digital transformation. Various components, including embedded structures and systems with complex architectures that incorporate IC semiconductors, are being integrated and modularized. As a result, there has been a significant increase in vehicle defects, raising expectations for the quality of automotive parts. As more and more data is being accumulated, there is an active effort to go beyond traditional reliability analysis methods and apply machine learning models based on the accumulated big data. However, there are still not many cases where machine learning is used in product development to identify factors of defects in performance and durability of products and incorporate feedback into the design to improve product quality. In this paper, we applied a prediction algorithm to the defects of automotive door devices equipped with automatic responsive sensors, which are commonly installed in recent electric and hydrogen vehicles. To do so, we selected test items, built a measurement emulation system for data acquisition, and conducted comparative evaluations by applying different machine learning algorithms to the measured data. The results in terms of R² score were as follows: Ordinary multiple regression 0.96, Ridge regression 0.95, Lasso regression 0.89, Elastic regression 0.91.

• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.24-28
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• 2012

In this study, we fabricated an amorphous InGaZnO pseudo-MOS transistor (a-IGZO ${\Psi}$-MOSFET) with a stacked $Si_3N_4/SiO_2$ (NO) gate dielectric and evaluated reliability of the devices with various thicknesses of a $SiO_2$ buffer layer. The roles of a $SiO_2$ buffer layer are improving the interface states and preventing degradation caused by the injection of photo-created holes because of a small valance band offset of amorphous IGZO and $Si_3N_4$. Meanwhile, excellent electrical properties were obtained for a device with 10-nm-thick $SiO_2$ buffer layer of a NO stacked dielectric. The threshold voltage shift of a device, however, was drastically increased because of its thin $SiO_2$ buffer layer which highlighted bias and light-induced hole trapping into the $Si_3N_4$ layer. As a results, the pseudo-MOS transistor with a 20-nm-thick $SiO_2$ buffer layer exhibited improved electrical characteristics and device reliability; field effective mobility(${\mu}_{FE}$) of 12.3 $cm^2/V{\cdot}s$, subthreshold slope (SS) of 148 mV/dec, trap density ($N_t$) of $4.52{\times}1011\;cm^{-2}$, negative bias illumination stress (NBIS) ${\Delta}V_{th}$ of 1.23 V, and negative bias temperature illumination stress (NBTIS) ${\Delta}V_{th}$ of 2.06 V.

• 한국시스템다이내믹스연구
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• 제8권2호
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• pp.5-23
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• 2007

According to the system dynamics model of this study, if there is a significant network effect on vehicle operating costs, it is difficult to achieve the shift to AFV even in the long term without a policy intervention because the car market is locked in to the current structure. Network effect can be caused by an increasing return to scale in fuel supply sector as well as in maintenance service sector. It is also related to the fact that the reliability and awareness of consumers on new products increases with the growth of the market share of the new products. There are several possible policy options to break the 'locked in' structure of car market, such as subsidy on vehicle price (capital cost), subsidy on fuel (operating cost) and niche management policy. Combined policy options would be more effective than relying on a single policy option to increase the market share of AFV.

• International Journal of Control, Automation, and Systems
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• 제6권5호
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• pp.627-638
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• 2008

With the shift of the electric power industry from a regulated monopoly structure to a competitive market environment, the focus of the transmission expansion planning has been moving from reliability-driven transmission expansion to market-based transmission expansion. In market-based transmission expansion, however, a growing demand for electricity, an increasing number of transmission bottlenecks, and the falling levels of transmission investment have created the need for an incentive to motivate investors. The expectation of profit serves as a motivational factor for market participants to invest in transmission expansion in a competitive market. To promote investment in transmission expansion, there is an increasing need for a systematic method to examine transmission expansion for investment incentives from multiple perspectives. In this paper, the transmission expansion problem in a competitive market environment is formulated from ISO and investors' perspectives. The proposed method uses parametric analysis to analyze benefits for investors to identify the most profitable location and amount for transmission addition. Numerical results are presented to demonstrate the effectiveness of the proposed method.