• 센서학회지
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• 제20권6호
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• pp.393-399
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• 2011

In this paper, we designed and fabricated the novel air flow sensor using air drag force, which can be applied to the low air flow detection. To measure the low air flow, we should enlarge the air drag force and the output signal at the given air flow. The paddle structure is applied to the device, and the device is vertically located against the air flow to magnify the air drag force. We also adapt the corrugation structure to improve the output signals on the given air velocity. The device structure is made up of the silicon nitride layer and the output signal is measured with the piezoresistive layer. The output signals from the corrugated device show the better measurement sensitivity and the response time than that of flat one. The repeated measurement also shows the stabilized signals.

• 전자통신동향분석
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• 제34권3호
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• pp.93-105
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• 2019

This study emphasizes the importance of the newly added Ultra-Reliable and Low-Latency Communications (URLLC) service as an important evolutionary step for 5G mobile communication, and proposes a remedial application. We analyze the requirements for the application of 5G mobile communication technology in high-precision vertical industries and applications, introduce the 5G URLLC design principles and standards of 3GPP, and summarize the current state of applied artificial intelligence technology in wireless communication. Additionally, we summarize the current state of research on ultra-reliable and low-latency machine learning-based wireless communication technology for application in ultra-high-precision vertical industries and applications. Furthermore, we discuss the technological direction of artificial intelligence technology for URLLC wireless communication.

• 한국재료학회지
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• 제27권11호
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• pp.636-642
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• 2017

In the present study the microstructure of low-carbon steels fabricated by controlled rolling and accelerated cooling processes was characterized and identified based on various microstructure analysis methods including optical and scanning electron microscopy, and electron backscatter diffraction(EBSD). Although low-carbon steels are usually composed of ${\alpha}-ferrite$ and cementite($Fe_3C$) phases, they can have complex microstructures consisting of ferrites with different size, morphology, and dislocation density, and secondary phases dependent on rolling and accelerated cooling conditions. The microstructure of low-carbon steels investigated in this study was basically classified into polygonal ferrite, acicular ferrite, granular bainite, and bainitic ferrite based on the inverse pole figure, image quality, grain boundary, kernel average misorientation(KAM), and grain orientation spread(GOS) maps, obtained from EBSD analysis. From these results, it can be said that the EBSD analysis provides a valuable tool to identify and quantify the complex microstructure of low-carbon steels fabricated by controlled rolling and accelerated cooling processes.

• 벤처창업연구
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• 제9권1호
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• pp.153-164
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• 2014

R&D는 산업과 제품의 특성에 따라 그 중요도가 다르며, 제품의 고부가가치를 중요시하는 첨단산업에 있어서 R&D의 중요성이 크다. 그런데 첨단산업의 기업은 전통적인 상장기업에 비해 재무변수의 기업가치 설명력이 상대적으로 낮게 나타나는데 그 원인은 재무제표에 기록되지 않은 무형자산 때문인 것으로 추정된다. 이에 본 연구의 목적은 코스닥기업을 첨단산업과 비첨단산업으로 나누어 무형자산성 지출의 가치관련성을 분석하는 것이다. 무형자산성 지출은 연구개발비, 교육훈련비, 광고선전비로 측정하였다. 분석 결과 첫째, 첨단산업에서는 연구개발비가 기업가치에 양(+)의 유의한 영향을 미치는 것으로 나타났고 교육훈련비는 기업가치에 음(-)의 유의한 영향을 미치는 것으로 나타났다. 비첨단산업에 있어서는 교육훈련비가 기업가치에 양(+)의 유의한 영향을 미치는 것으로 나타났다. 첨단산업과 비첨단산업 모두 광고선전비는 유의한 영향을 미치지 않는 것으로 나타났다. 둘째, 대형회계법인의 감사품질은 첨단산업의 연구개발비의 가치관련성을 더욱 증가시키고 비첨단산업의 교육훈련비의 가치관련성을 증가시키는 역할을 하는 것으로 나타났다. 이러한 연구결과는 투자자들이 전자, 통신, 제약, 정밀기계와 같은 첨단산업군의 연구개발비 투자에 대해 비첨단산업군의 연구개발비 투자와 비교해서 더 가치 있는 투자로 평가하는 것으로 해석할 수 있다. 본 연구의 연구결과는 첨단산업과 비첨단산업의 경영자의 무형자산성 투자의 의사결정에 있어서 유익한 참고가 될 수 있을 것으로 기대한다.

• 한국수소및신에너지학회논문집
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• 제34권2호
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• pp.113-121
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• 2023

Recently, low hydrogen carbon production technology is drawing interest due to lower production costs. Although the pace of research in this field has been accelerating, there is no well-established criteria for evaluation. The most of current evaluation methods needs information related to technology. However the technology is not enough to provide effective evaluation criteria because the technology is not fully developed. In this study, we propose an integrated Delphi-analytic hierarchy process (AHP) method and low carbon hydrogen production technology evaluation model. Experts opinion is used to provide evaluation criteria for the technology. In this study, integrated Delphi-AHP method are utilized for determining factors and calculating their numerical importance based on experts opinion. Then, sensitivity analysis is performed to verify the robustness of the analysis and scenarios of potential changes. As many as 11 factors are identified by Delphi method. Then, numerical importance of the factors are calculated by AHP. Sensitivity analysis is performed. It shows that intellectual property right (IPR) is always more important than other factors. This study proposes the numerical standard for the low carbon hydrogen production technology evaluation. The proposed model can be used for technology evaluation or commercialization.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.207-210
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• 2008

The effects of boron additions in steels have long been recognized as very important, mainly with respect to hardnability of heat treatable steels. we investigated the effect of the microstructure and mechanical properties with cooling condition after heat treatment of the boron-treated(${\fallingdotseq}8{\sim}18ppm$) low carbon(${\fallingdotseq}0.2%C$) low alloy steel. The specimens were austenitised for 10 min at $910^{\circ}C$, cooled for the various periods of time from 10 sec to 30 sec or with water after forming for 15 sec. After cooling, mechanical properties were measured by tensile test and hardness test. For analysis of microstructure, Optical were carried out.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.259-262
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• 2009

The influence of pre-strain in low-cycle fatigue behavior of Fe-18Mn-0.05Al-0.6C TWIP steel was studied by conducting axial strain-controlled tests. As-received plates were deformed by rolling with reduction ratios of 10 and 30%, respectively. A triangular waveform with a constant frequency of 1 Hz was employed for low cycle fatigue test at the strain amplitudes in the range of ${\pm}0.4{\sim}{\pm}0.6$ pct. The results showed that low-cycle fatigue life was strongly dependent on the amount of pre-strain as well as the strain amplitude. Increasing the amount of prestrain, the number of reversals to failure was significantly decreased at high strain amplitudes, but the effect was negilgible at low strain amplitudes. A new model for predicting fatigue life of pre-strained body has been devised adding a correction term of ${\Delta}E_{pre-strain}$ to the energy-based fatigue damage parameter.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.254-258
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• 2009

In this paper, the low frequency vibration forming system is developed for micro-patterns formation on the metal substrate. many researchers have studied about micro-forming technologies such as micro deep drawing, press forming, forging, extrusion etc. for the formation of precise micro-patterns on the surface of metal substrates, multi-step forming process must be used to improve qualifies of the deformed patterns. Since the low frequency vibration forming system could easily deform the surface of metal substrates, several steps of multi-step forming process should be removed by using the low frequency vibration forming system. In order to find optimal process conditions, we have carried out low frequency vibration forming process with varying the vibration frequency from 110Hz to 500Hz.

• 산업기술연구
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• 제22권A호
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• pp.3-8
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• 2002

In this study, extremely low cycle fatigue tests were carried out under push-pull loading conditions using graphite cast iron (GCD). In order to clarify the fatigue fracture mechanism of GCD in an extremely low cycle fatigue regime successive observations of internal fatigue damage were performed. The results obtained are as follows. (1) The process of extremely low cycle fatigue can be classified into three stages which are composed of the generation, growth and coalescence of microvoids inside materials. (2) In an extremely low cycle fatigue regime, microvoids originate from debonding of graphite-matrix interface.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.191-194
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• 2005

In this paper the platform system for IEEE 802.15.4 Low Rate WPAN is designed and fabricated. IEEE 802.15.4 Low Rate WP AN system serves the functions and realization of home-area network. According to the IEEE 802.15.4 standard, there are two modes, One is BPSK modulation in 868/915MHz frequency band. The other is O-QPSK modulation in 2.45GHz frequency band. In this paper we implemented the platform system mounted in one PCB board in 868/915MHz frequency band of IEEE 802.15.4 Low Rate WPAN system. We measured that the platform system which consists of digital part and RF part has good performance. Also RF part is realized by design and fabrication of the RF transceiver IC. The key issue is to make the platform system which provides the function of Low Rate WPAN system to meet the requirement of IEEE 802.15.4 standards.