• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.11
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• pp.76-83
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• 2006

Space radiation environment for COMS is simulated by NASA AP8/AE8, JPL91 and NRL CREME models, respectively for trapped particle, solar proton and cosmic-ray. The radiation effects on electronic devices in communication payload are also estimated by using simulation results. Dose-depth curve and LET spectrum are calculated for estimating total ionizing dose(TID) effect and single event effect(SEE) respectively. Spherical sector method is applied to dose estimation at each position in the units of communication payload to consider shielding effect of platform and housing. Total ionizing dose at each position varies by 8 times through shielding effect under the same external space radiation environment.

• Korean Journal of Materials Research
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• v.13 no.1
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• pp.18-23
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• 2003

Properties of Ag thick films fabricated by using low temperature curable silver pastes were investigated. Ag pastes were consisted of polymer resins and silver powders. Ag pastes were used for conductive or fixing materials between board and various electrical and electronic devices. Low temperature curable Ag pastes have some advantages over high temperature curable types. In cases of chip mounting, soldering properties were required for screen printed Ag thick films. In this study, four types of Ag pastes were fabricated with different compositions. Screen printed Ag thick films on alumina substrates were fabricated at various curing temperatures and times. Thickness, resistivity, adhesive strength and solderability of fabricated Ag thick films were characterized. Finally, Ag thick films produced using Ag pastes, sample A and B, cured at $150^{\circ}C$ for longer than 6 h and $180^{\circ}C$ for longer than 2 h, and $150^{\circ}C$ for longer than 1 h and $180^{\circ}C$ for 1 h, respectively, showed low resistivities of $10^{-4}$ $∼10^{-5}$ Ωcm and good adhesive strength of 1∼5 Mpa. Soldering properties of those Ag thick films with curing temperatures at solder of 62Sn/36Pb/3Ag were also investigated.

• Korean Journal of Materials Research
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• v.22 no.3
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• pp.140-144
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• 2012

Compared with bulk material, quantum dots have received increasing attention due to their fascinating physical properties, including optical and electronic properties, which are due to the quantum confinement effect. Especially, Luminescent CdSe quantum dots have been highly investigated due to their tunable size-dependent photoluminescence across the visible spectrum. They are of great interest for technical applications such as light-emitting devices, lasers, and fluorescent labels. In particular, quantum dot-based light-emitting diodes emit high luminance. Quantum dots have very high luminescence properties because of their absorption coefficient and quantum efficiency, which are higher than those of typical dyes. CdSe quantum dots were synthesized as a function of the synthesis time and synthesis temperature. The photoluminescence properties were found strongly to depend on the reaction time and the temperature due to the core size changing. It was also observed that the photoluminescence intensity is decreased with the synthesis time due to the temperature dependence of the band gap. The wavelength of the synthesized quantum dots was about 550-700 nm and the intensity of the photoluminescence increased about 22~70%. After the CdSe quantum dots were synthesized, the particles were found to have grown until reaching a saturated concentration as time increased. Red shift occurred because of the particle growth. The microstructure and phase developments were measured by transmission electron microscopy (TEM) and X-ray diffractometry (XRD), respectively.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.20.2-20.2
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• 2011

BMNO dielectric materials with a pyrochlore structure have been chosen and they have quite high dielectric constants about 210 for the bulk material. In the case of thin films, 200-nm-thick BMNO films deposited at room temperature showed a low leakage current density of about $10^{-8}\;A/cm^2$ at 3 V and a dielectric constant of about 45 at 100 kHz. Because high dielectric constant BMNO thin films kept an amorphous phase at a high temperature above $900^{\circ}C$. High dielectric constant BMNO thin films grown at room temperature have many applications for flexible electronic devices. However, because the dielectric constant of the BMNO films deposited at room temperature is still low, percolative BMNO films (i.e., those were grown in a pure argon atmosphere) sandwiched between ultra-thin BMNO films grown in an oxygen and argon mixture have greater dielectric constants than standard BMNO films. However, they still showed a leakage problem at a high voltage application. Accordingly, a new nano-structure that uses BMNO was required to construct the films with a dielectric constant higher than that of its bulk material. The fundamental reason that the BMNO-Bi nano-composite films grown by RF-Sputtering deposition had a dielectric constant higher than that of the bulk material was addressed in the present study. Also we used the graphene as bottom electrode instead of the Cu bottom electrode. At first, we got the high leakage current density value relatively. but through this experiment, we could get improved leakage current density value.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.5113-5119
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• 2010

Anthropometry has been broadly explored in various fields including automobile industry, home electronic appliances, medical appliances and sports goods with aiming at reaching satisfaction to consumer's need and efficiency. However, current technologies to measure a human body still have barriers in which the methods mostly seem to be contingent on expensive devices such as scanner and digital measuring instruments and to be directly touchable to the body when obtaining body size.. Therefore, in this paper, we present a general method to automatically extract size of body from a real body image acquired from a camera and to utilize it into recommend systems including clothing and bicycle fitting. At first, Haar-like features and AdaBoost algorithm are employed to detect body position. Then features of body can be recognized using AAM. Finally clothing and bicycle recommending modules have been implemented and experimented to validate the proposed method.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.764-765
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• 2011

전력시스템을 더 효율적으로 운용하고, 더 지능화하려는 노력은 2000년대 초 다양한 각도로 진행되어 왔다. 그리하여 중장기 국책과제인 전력IT 과제를 필두로 여러 지능화 기기들이 국 내외 유관업체를 통하여 지속적으로 성장을 하였고 현재에 이르러서는 과제의 틀이 아닌 비즈니스 모델 창출을 위하여 여러 시범 사업들이 구상되고 있는 중이다. 이는 전력IT 의 핵심 아이템이라 할 수 있는 IEC-61850 국제 표준 프로토콜 기반의 IED (Intelligent Electronic Devices) 개발과 어울려 변전소의 직접 현장 적용을 통한 엔지니어링 기술 개발에 역점을 두고 있는 상태이다. 변전소 자동화 (S/A: Substation Automation)의 영역이 점점 현실화 되어가고, 전 세계 적용 Site의 폭발적인 증가로 힘입어 이젠 선택이 아닌 필수가 되고 있고, 적용에서 끝이 아닌 다양한 엔지니어링 Tool 의 개발, 진단 시스템의 융합 등과 더불어 계속 발전해나가고 있다. 본 논문에서는 이러한 시대적 흐름을 바탕으로 당사에서 참여중인 한국전력 154kV S/A 시범사업 및 스마트그리드 실증사업을 통하여 현장 적용된 154kV Main Transformer 용 IED 솔루션의 적용 사례를 소개하고자 한다. S/A 시범사업의 경우, 한국전력 충주본부 풍동S/S에서 올해 초 설계되어 현재 현장 엔지니어링을 1차 마무리한 상태이며, 스마트 그리드 실증사업은 제주 성산S/S에서 진행 중이며 이도 마무리를 하는 단계에 이르러, 그동안 현장적용의 문제점을 논의하고, 이에 대한 대응책을 서로 공유하며 정리하고 있다. 참고로 본 논문에서는 IEC-61850 프로토콜 구현에 대한 것은 다루지 않으며, 다만 현장제어에 필요하고 또한 구현되어 있는 기능에 대한 전반적인 내용을 다루게 된다.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.1225-1232
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• 2009

최근 HCI 분야에서는 사용자들이 가지고 있는 문화적 성향이 사용자 경험에 미치는 영향에 대한 다양한 연구들이 이루어져 왔다. 이는 사용자들이 가지고 있는 문화적 성향이 어떠한 기기나 시스템을 이해하고 해석하는 방식에 영향을 미치는 지각적 렌즈(Perceptual Lens)로서 작용하기 때문이다. 이와 같은 사용자들이 가지고 있는 문화적 성향의 중요성에도 불구하고 기존 HCI 분야의 연구들은 국가와 문화를 동일시하면서 국가 수준에서 문화의 중요성만을 강조하고 있다. 그러나 어떠한 기기나 시스템의 사용은 개인 수준에서의 행동이기 때문에 국가와 문화를 동일시 하는 것은 개인 수준의 행동을 설명하지 못한다는 한계가 있다. 이는 문화적 성향이 한 국가 내에서도 개인에 따라 다양한 양상을 나타낼 수 있으며, 더 나아가 한 개인 안에서도 대상이나 정황에 따라 다른 양상을 나타낼 수 있기 때문이다. 본 연구는 사용자들이 가지고 있는 문화적 성향에 있어 국가 간 차이가 존재할 뿐만 아니라, 기기 간에도 차이가 존재함을 밝히는 것을 기본 목적으로 한다. 이와 같은 목적을 위하여 본 연구에서는 Hofstede[1980]가 제시한 네 가지 문화적 차원(불확실성 회피 성향, 개인주의 성향, 남성성 성향, 권력 거리 성향)을 중심으로 각 차원에 있어 나타나는 국가 간 그리고 기기 간 사용자들의 문화적 성향의 차이를 3 개 국(미국, 독일, 러시아)에서 4 개 디지털 기기(핸드폰, MP3 플레이어, LCD TV, 냉장고) 사용자들을 대상으로 한 대규모 설문을 기반으로 검증하였다.

• The Korean Journal of Pain
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• v.5 no.2
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• pp.229-233
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• 1992

Recently a non-electronic, disposable and portable infusor, Baxter $Infusor^{(R)}$, has developed for delivering not only a continuous drug infusion but also extradoses of medication on a demand basis. The present study examined the impact of two methods of pain management on recovery in 20 patients undergoing upper abdominal surgery for stomach cancer. One group, 10 patients, received IV meperidine in the recovery room and IM meperidine on the ward on a PRN basis(PRN group). In the other group, 10 patients, a loading dose of nalbuphine 0.1mg/kg was given when the patient first complained of pain in the recovery room and patient controlled analgesia with IV nalbuphine, 0.5mg/kg day for continuous infusion, was initiated and continued for 72 hours(PCA group). The devices for PCA group was Baxter Infusor with patient control module which had flow rate 0.5ml/hr and lockout time was 15 min. As results of this study, the patients of PCA group get less pain than PRN group on operation day, the first and second days after surgery. VAPS values are $6.47{\pm}1.64$ vs $4.44{\pm}1.38$, $5.02{\pm}1.22$ vs $2.62{\pm}0.93$ and $3.22{\pm}1.47$ vs $2.02{\pm}0.71$ respectively pertaining to PRN and PCA groups(p<0.05). In conclusion, PCA group with IV nalbuphine provided more effective postoperative analgesia than PRN group with conventional meperidine IM.

• Journal of the Korean Electrochemical Society
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• v.11 no.2
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• pp.125-129
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• 2008

Rechargeable lithium-ion polymer batteries have been considered to be next-generation power sources for portable electronic devices and electric vehicles. In this work, we tried to improve the cycling performances of lithium-ion polymer cells by coating aluminum fluoride and acrylonitrile-methyl methacrylate copolymer to the polyethylene separator. It was found that the addition of aluminum fluoride to the surface-modified separator reduced the interfacial resistances and thus the cell exhibited a less capacity fading and better high rate performance. The cell showed an initial discharge capacity of 150 mAh/g and good capacity retention at 0.5 C rate.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.2
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• pp.145-152
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• 2020

In this paper, we propose the Crop Classification Management System (CCMS) that detects changes in growth environment to improve crop production rate. The CCMS consists of two modules. First, the Crop Classification Module (CCM) classifies crops through CNN. Second, the Farm Anomaly Detection Module (FADM) detects abnormal crops by comparing accumulated data of farms. The CCM recognizes crops currently grown on farms and sends them to the FADM, and the FADM picks up the weather data from the past to the present day of the farm growing the crops and applies them to the Nelson rules. The FADM uses the Nelson rules to find out weather data that has occurred and adjust farm conditions through IoT devices. The performance analysis of CCMS showed that the CCM had a crop classification accuracy of about 90%, and the FADM improved the estimated yield by up to about 30%. In other words, managing farms through the CCMS can help increase the yield of smart farms.