• 한국전기전자재료학회논문지
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• 제21권5호
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• pp.411-414
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• 2008

The germanium films were deposited by metal organic chemical vapor deposition using $Ge(allyl)_4$ precursors on TiAlN substrates. Deposition of germanium films was only possible with a presence of $Sb(iPr)_3$, which means that $Sb(iPr)_3$ takes a catalytic role by a thermal decomposition of $Sb(iPr)_3$ for Ge film deposition. Also, as Sb bubbler temperature increases, deposition rate of the Ge films increases at a substrate temperature of $370^{\circ}C$. The GeTe thin films were fabricated by MOCVD with $Te(tBu)_2$ on Ge thin film. The GeTe films were grown by the tellurium deposition at $230-250^{\circ}C$ on Ge films deposited on TiAlN electrode in the presence of Sb at $370^{\circ}C$. The GeTe film growth on Ge films depends on the both the tellurium deposition temperature and deposition time. Also, using $Sb(iPr)_3$ precursor, GeSbTe films with hexagonal structures were fabricated on GeTe thin films. GeSbTe films were deposited in trench structure with 200 nm*120 nm small size.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.851-853
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• 2004

This paper deals with current distribution analysis of the windings of a superconducting transformer with BSCCO-2223 High Tc Superconducting (HTS) tapes. Current distribution of HTS windings wound in parallel is analyzed by electromagnetic field analysis of finite element method and verified by experiments. For the sake of uniform current distribution, windings must be transposed so to make the impedances of each strands same. The parallel HTS tapes were transposed between the pancakes via non-superconducting joints because it is hard to make transpositions inside the pancake windings. In order to measure current distribution, test windings are fabricated and experimented for both transposed and non-transposed windings. We compared test results with calculated ones.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권5호
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• pp.586-590
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• 2010

본 논문에서는 선형 추세 제거 서브시퀀스 매칭을 정의하고, 이를 효율적으로 수행하기 위한 인덱스 기반 해결책을 제안한다. 이를 위해, 먼저 윈도우 자체의 선형 추세가 아닌 해당 윈도우를 포함하는 서브시퀀스의 선형 추세를 제거하여 얻은 새로운 윈도우인 LD-윈도우 개념을 제시한다. 다음으로, LD-윈도우를 이용하여 제안하는 인덱스 기반 해결책의 이론적 근거인 하한 조건을 제시하고, 이를 정형적으로 증명한다. 이러한 하한 조건에 기반하여, 본 논문에서는 또한 인덱스 구성 및 서브시퀀스 매칭 알고리즘을 각각 제안한다. 마지막으로, 실험을 통해 제안하는 인덱스 기반 해결책의 우수성을 입증한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.54-60
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• 1994

The cause of black out of Tokyo Power in 1987 has been identified as the voltage stability problem. After this event many researchers has been interested in voltage stability or voltage collapse phenomena. The voltage instability is different Com the transient stability in the sense of reactive power mismatch and the long duration time. In this study, we developed efficient tool for analyze and control the dynamic voltage instability. To analize specific condition of dynamic voltage stability, quasi-dynamic simulation method is developed. To provide proper mathmatical model for dynamic voltage stability, generator, SVC, OLTC, induction motor models are introducted. To provide specified dynamic voltage stability, the authors considered to use reactive loss function(${\partial}Q/{\partial}p_L$) as reactive power facility control index. This program was tested and identified its usefulness in real KEPCO system.

• 전기학회논문지
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• 제58권11호
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• pp.2223-2228
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• 2009

Dye sensitized solar cells(DSCs) have been very economical and easy method to convert solar energy to electricity. DSC can reach low costs in future outdoor power applications. However, to commercialize the DSC, there are still many shortages to overcome such a low efficiency in a large size DSC. In this study, DSCs were fabricated by an electrospray coating method for the $TiO_2$ thin film. They were compared with DSCs prepared by conventional coating methods. We conducted an experiment to obtain the optimized parameters of voltage, flow rate, incident angle and distance in the electrospray method. After we fabricated $TiO_2$ film using that way, we investigated the characteristics of DSC through I-V Curve, SEM and EIS. This novel method shows stable performance with an energy conversion efficiency of 3.44 % under 1 sun illumination (AM 1, $P_{in}$ of $100\;mW/cm^2$).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.959-960
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• 2007

The wind power has been used steadily since long ago, but the importance of it has been faded because of the abundant and convenient fossil energy. Now, due to the energy crisis, experiencing the environmental problems etc, the necessity of using it growing bigger. Because the small wind turbines under a few kW grade has the merits of setting up with low costs by individuals, and get the energy saving effects that, it has the secured, separate markets from the range systems, and the developing of it is continuously proceeding. The small wind turbine system must have the output power regulating system for the over wind speed, to run steadily in the various wind speed environment. In case of the small wind turbine system, to prevent the breaking and for safety, at the over wind speed, additional system is required, and in most cases, output power is restricted by mechanical means. In this paper, the furling system makes the tail and the head move to make the blades to the wind in slanted angle, restrict the output power at the over wind speed. In thesis, small prototype wind turbine is made, and analyzing the output power characteristics at the over wind speed, and to verify, through the logical study and tests.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.88-90
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• 2002

The $BaTi_4O_9$ ceramics with $Y_2O_3$(0.5wt%) were prepared by the conventional mixed oxide method. The structural properties were investigated with sintering temperature by XRD. The microwave dielectric properties also were investigated as a function of sintering temperature. According to the X-ray diffraction pattern of the $BaTi_4O_9$ ceramics with $Y_2O_3$(0.5wt%), the orthorhombic $BaTi_4O_9$ were appeared. In the case of $BaTi_4O_9+Y_2O_3$(0.5wt%) ceramics sintered $1400^{\circ}C$, dielectric constant. quality factor and temperature coefficient of resonant frequency were 41.3, 41,600, $+3.2ppm/^{\circ}C$, respectively.

• 대한음성학회지:말소리
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• 제61호
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• pp.75-86
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• 2007

In this paper, we propose a scalable audio coder, which has a variable bandwidth from the narrowband speech bandwidth to the audio bandwidth and also has a bit-rate from 8 to 320 kbits/s, in order to cope with the quality of service(QoS) according to the network load. First of all, the proposed scalable coder splits bandwidth of the input audio into narrowband up to around 4 kHz and above. Next, the narrowband signals are compressed by a speech coding method compatible to an existing standard speech coder such as G.729, and the other signals whose bandwidth is above the narrowband are compressed on the basis of a psychoacoustic model. It is shown from the objective quality tests using the signal-to-noise ratio(SNR) and the perceptual evaluation of audio quality(PEAQ) that the proposed scalable audio coder provides a comparable quality to the MPEG-1 Layer III (MP3) audio coder.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.338-338
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• 2010

공정 중 발생하는 입자는 반도체 생산 수율에 가장 큰 영향을 끼치는 원인으로 파악되며, 생산 수율을 저하시키는 원인 중 70% 가량이 이와 관련된 것으로 알려져 있다. 현재 반도체 공정에서 입자를 계측하는데 사용하는 PWP (Particle per Wafer Pass) 방법은 표준 측정방법으로 널리 쓰이고 있으나, 실시간으로 입자의 양을 측정할 수 없고, Test wafer 사용에 따른 비용증가의 단점이 있어 공정 중에 입자를 실시간으로 측정할 수 있는 대안기술이 필요한 실정이다. ISPM (In-Situ Particle Monitoring)은 레이저 산란방식을 이용한 실시간 입자측정 장비로서 오염원 발생에 대한 즉각적인 대처와 조치가 가능하고 부가적인 추가 비용이 발생하지 않기 때문에 실시간 모니터링 장비가 없는 현재의 반도체 공정에 충분히 적용될 가능성이 있다. 특히 CVD 공정은 반도체 공정의 약 30%를 차지할 만큼 중요한 단계로 생성되는 오염입자 모니터링을 통해 공정 불량 유무를 판단할 수 있을 것으로 기대된다. 본 연구에서는 Silane 가스를 이용한 PECVD (Plasma Enhanced Chemical Vapor Deposition) 공정 중 발생되는 오염입자를 ISPM을 이용하여 실시간으로 측정하였다. 챔버 배기구에 두 가지 타입의 ISPM을 설치하고 공정압력, 유량, 플라즈마 파워를 공정변수로 하여 각각의 조건에서 발생되는 오염입자의 분포 변화를 실시간으로 측정하였으며 결과를 비교 분석하였다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2015년도 추계학술발표대회
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• pp.1470-1473
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• 2015

최근 빠른 인터넷 속도를 이용하여 SNS (Social Network Service), 인터넷 방송 등의 엔터테인먼트를 즐기는 사용자가 증가하였다. 이와 함께 직접 사진, 동영상 등의 멀티미디어를 직접 제작해 제공하는 사례도 크게 증가함에 따라 영상처리 기술이 발전하였다. 이에 따라 셀프촬영이 점점 증가하고 있지만, 동영상의 경우는 셀프촬영을 하는데 있어 한계가 있다. 이 문제를 해결하기 위한 한 방법으로 영상처리를 이용할 수 있다. 하지만 현재의 기술은 고성능에 초점이 맞춰있기 때문에 시스템 구현을 위해 비용 낭비가 발생할 수 있다. 따라서 본 논문에서는 셀프 동영상 촬영 분야의 적외선 영상처리 기반 저비용 사용자 추적 시스템을 제안한다. 실제 단순히 인식률을 측정한 결과 80%를 보였으며, 속도에 따라 1.5m/s에서 76%의 인식률을 보였다.