• 한국추진공학회지
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• 제22권1호
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• pp.80-88
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• 2018

한국형 발사체 지상고정 장치는 발사체 이륙시 엔진 최대 추력에서 고정을 해제 한다. 고정력을 일시에 제거하면 추진체가 탱크 내부에서 상하로 진동하는 Ka Doing a Doing a Doing Mode를 유발할 수 있으므로, 점진적으로 고정력을 제거하는 기능이 필요하다. 본 연구에서는 이를 만족하기 위해 축압기 및 파이로 밸브로 유압구동기를 작동하고 구동기내 오리피스로 속도를 제어하는 지상고정장치 유압시스템의 작동 시험을 수행하였다. 주요 설계변수 변화 의한 유압구동기 운동속도의 영향을 분석하여 이를 바탕으로 구동기 요구속도를 만족시킬 수 있는 유압구동기 설계값들을 도출하였다. 이를 통하여 최대추력에서 동작할 수 있는 발사체 지상고정 장치의 개발을 위한 공학적 기반을 마련하였다.

• Journal of information and communication convergence engineering
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• 제15권1호
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• pp.37-42
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• 2017

The constrained application protocol (CoAP) can be used for remotely controlling various sensor devices in Internet of Things (IoT) networks. In CoAP, to support the handover of a mobile sensor device, service discovery and message transmission needs to be repeated, although doing so would increase the handover delay significantly. To address this limitation of CoAP, a centralized CoAP scheme has been proposed. However, it tends to result in performance degradation for an inter-domain handover case. In this letter, we propose a distributed CoAP handover scheme to support the inter-domain handover. In the proposed scheme, a distributed mobility agent (DMA) is used for managing the location of mobile sensors in a domain and performing handover control operations with its neighboring DMAs in a distributed manner. A performance comparison reveals that the proposed scheme offers a performance improvement of up to 29.5% in terms of the handover delay.

• 반도체디스플레이기술학회지
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• 제13권1호
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• pp.91-95
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• 2014

(F,Ga) co-doped ZnO thin film on glass substrate was fabricated via a simple non-alkoxide sol-gel spin-coating. Contrary to the F single doped ZnO thin film, the (F,Ga) co-doped thin film showed a significant reduce in electrical resistivity after a second post-heat-treatment in reducing environment. The resulting decrease in electrical resistivity with Ga co-doping is considered to be resulted from the increases both carrier density and mobility. The optical transmittance of the (F,Ga) co-doped thin film in the visible range showed higher transmittance with Ga co-doping compared with F single doped ZnO thin film.

• 재활치료과학
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• 제11권4호
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• pp.7-22
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• 2022

목적 : 본 연구는 국내 CO-OP 중재 연구를 체계적으로 고찰하여 임상적 근거를 제공하고자 한다. 연구방법 : 본 연구는 2015년 1월부터 2021년 12월까지 학술연구정보서비스(RISS), 학술교육원(e-article) 데이터베이스에 게재된 문헌 중 선정기준에 적합한 13편의 논문을 최종적으로 선택하여 연구 방법의 내용에 따라 일반적 특성과 질적 수준으로 나누어 분석하였다. 결과 : 연구 내용을 분석한 결과, 2015년 이후 연구가 지속적으로 진행되었으며 CO-OP 중재 연구의 근거 수준은 개별대상연구가 주를 이루었다. 연구 대상은 아동과 성인 모두에게 적용되고 있었으며, CO-OP 중재의 목표 활동 영역으로 아동은 놀이와 여가, 성인은 수단적 일상생활 영역으로 나타났다. 중재의 효과를 살펴보기 위한 평가로는 COPM과 PQRS 평가를 많이 사용하였으며 구체화 전략으로는 아동은 자세, 집중하기, 과제변형, 언어적 상상을 많이 사용하였고 성인은 자세, 집중하기, 과제변형, 움직임에 대한 느낌, 언어적 상상, 과제 촉진 언어를 주로 사용한 것으로 나타났다. 결론 : 본 연구를 통해 국내 CO-OP 중재를 적용한 연구의 특성과 질적 수준을 확인할 수 있었다. CO-OP 중재가 작업치료 분야에서 지속해서 적용되고 있으며, 적용 연령과 진단군이 확대되고 있음을 알 수 있었다. 국내 CO-OP 중재 연구의 체계적 고찰을 통해 임상에서 CO-OP 중재를 실행하기 위한 근거 자료를 제공하였다는 데 의의가 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.277-280
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• 1991

We have developed 154kV OF cable accessories from 1987. 4 to 1990. 10 by doing assembly design, investing equipment, manufacturing inspecting parts, type testing in labortary, in our company, in KEPCO. The one of those accessories. Oil Stop Joint, has been developed by using Shield Metal Embeded Type Epoxy Unit. This is More reliable than old type.

• 대한임베디드공학회논문지
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• 제10권3호
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• pp.119-127
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• 2015

In the IoT(Internet of Things) environment, methods that user can access sensor node directly to collect sensing data or manage sensor in a gateway have a limitations. To solve this problem, cloud based sensor network architectures are proposed. In this paper, we proposed CoAP based IoT architecture that a lightweight gateway is used for data gathering instead of using a heavy traditional one and users can request sensing data through IoT applications running in the cloud environment and analyze signaling message cost. By doing so, our system can reduce message cost compared to the traditional gateway based system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.51-53
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• 1997

Even though, many types of induction motors are known, most of the single phase induction motors being used are of squirrel cage type. However, basic structure of the machine has not been changed a lot during the past century. Author had been experienced many experiments with modified rotor. The modification was completed by doing two procedures: an elimination of lamination in central pan of the rotor and filling of melted aluminium in it instead. This paper demonstrates the reason for higher efficiency.

• Elastomers and Composites
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• 제30권3호
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• pp.185-194
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• 1995

Membrane process has been employed to separate a specific substance from gas or liquid mixture, and treat wastewater. This is due to the fact that the substance of mixture can be permeated and separated selectively by membrane. Since Initial equipment and operation costs are not expensive, membrane process has been adopted in various fields such as petroleum Industry, chemistry, polymer, electronics, foods, biochemical industry and wastewater treatment. In this study, $CaCO_3$ particles impregnated in silicone rubber network were extracted by using supercritical carbon dioxide and pore distribution of silicone $rubber-CaCO_3$ was investigated with varying amount of extract. Silicone rubber has excellent mechanical properties such as heat-resistance, cold-resistance etc. and $CaCO_3$ has microporous structure. It is possible to make silicone $rubber-CaCO_3$ composite sheets via work-intensive kneading processes. In so doing $CaCO_3$ particles become distributed and impregnated in silicone rubber network. Supercritical carbon dioxide diffuse through composite sample, then sample is swollen. $CaCO_3$ in silicone rubber network Is dissolved in supercritical carbon dioxide, and its sites become pores. Pore distribution, pore shape and surface area are observed by SEM(scanning electron microscope) micrograph and BET surface area analyzer examination respectively. Pore characteristics of membrane suggest the possibilities that the membrane can be used for process of mixture separation and wastewater treatment.

• 미생물학회지
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• 제19권4호
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• pp.186-191
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• 1981

Protoplast production from Trichoderma koningii ATCC 26113 was investigated for the purpose of doing basic and applied researches by protoplast fusion of the cellulolytic filamentous fungus. High yields of protoplast were obtained by using the 18hr. old mycelia treated with the lytic enzyme Driselase of Kyowa Fermentation Co., Japan, in 0.6M $MgSO_4\;or\;(NH_4)_2SO_4$ as osmotic stabilizers. The optimum temeprature of mycelial digestion was about $28^{\circ}C$ and the number of protoplast increased rapidly after 3hr. digestion. Protoplasts produced at different periods showed distinct morphological heterogeneities in the whole size and the size of vacuole.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 춘계학술발표논문집 1부
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• pp.269-272
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• 2010

In this paper, we propose the computation reduction methods of delta pitch search that is used in G.723.1 vocoder. In order to decrease the computational amount in delta pitch search the characteristic of proposed algorithms is as the following. First, scheme to reduce the computation amount in delta pitch search uses NAMDF. Developed the second scheme is the skipping technique of lags in pitch searching by using the threshold value. By doing so, we can reduce the computational amount of pitch searching more than 64% with negligible quality degradation.