• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 한국방송공학회 2014년도 하계학술대회
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• pp.105-106
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• 2014

본 논문에서는 중요도 지도를 사용한 화소값 사이 척력 기반 영상 대조비 향상 기법을 제안한다. 공간상에서 인접한 화소들 사이에 자주 발생하는 화소값들의 차이를 크게 하면 효과적으로 영상의 디테일을 두드러지게 할 수 있다. 대조비 증가를 위해 화소값 사이 척력을 정의하고, 유효 화소값 사이 척력들의 합을 사용하여 대조비의 증가 정도를 조절한다. 중요도 지도는 영상의 화소마다 사람의 시선이 머무르는 정도를 상대적인 수치로 나타낸 것이다. 따라서 영상 화질을 개선할 때 중요도 지도를 사용하면 사람의 시선을 끄는 화소값들의 대조비를 선택적으로 높일 수 있다. 실험 결과를 통하여 제안 기법이 우수한 화질개선 영상을 생성함을 확인한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.390-391
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• 2007

LED Packaging 과정 중 Die bond 재료로 Silver epoxy를 사용하여 Packaging 한 후 T3Ster 장비로 열 저항 값(Rth)을 측정하였다. Silver epoxy 의 접착 두께를 조절하여 열 저항 값을 측정하였고, 열전도도 값이 다른 Silver epoxy를 사용하여 열 저항 값을 측정하였다. Silver epoxy 접착 두께가 충분하여 Chip 전면에 고루 분포되었을 경우 그렇지 않은 경우보다 평균 4.8K/W 낮은 13.23K/W의 열 저항 값을 나타내었고, 열전도도가 높은 Silver epoxy 일수록 열전도도가 낮은 재료보다 평균 4.1K/W 낮은 12K/W의 열 저항 값을 나타내었다.

• The Journal of Korean Society for Radiation Therapy
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• 제26권2호
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• pp.281-287
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• 2014

Purpose : The purpose of this study is to compare the plan quality of volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) for the treatment of orbital lymphoma. IMRT, partial single arc(SA) and partial-double arc(DA) VMAT plans for four patients with orbital lymphoma treated at our institution were used for this study. Conformity Index(CI), Paddick's Conformity Index(PCI) and Homogeneity Index(HI) of planning target volume(PTV) were used to evaluate dosimetric quality of each plan. The Monitor Unit (MU), treatment time and dose of ipsilateral lens from each type of plan were measured for comparison. Materials and Methods : The CI of PTV for IMRT, SA and DA were measured as 0.88, 0.86, 0.92. The PCI of DA was the lowest as 1.33. Also HI of DA was the lowest in measured plans as 1.15. Mean dose of lens, lacrimal gland, optic chiasm, the opposite optic nerve and both orbit was analyzed with V30, V20, V10, V5. The result showed that the lowest dose in IMRT highest in SA in opposite lens, lacrimal gland, optic nerve, orbit. Results : Treatment time and average MU of IMRT was about three times higher than SA. Conclusion : Considering the superior plan quality as well as the delivery efficiency of VMAT compared with that of IMRT, VMAT may be the preferred modality for treating orbital lymphoma.

• Journal of the Korean Society of Clothing and Textiles
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• 제25권10호
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• pp.1738-1744
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• 2001

본연구의 목적은 반응성 염료를 이용한 텐셀섬유의 피브릴화 조절 효과를 표면 형태, 감량율, 역학적 성질 및 태의 변화의 측면에서 고찰하는데 있다. 반응성 염료에 의한 가교는 섬유의 비결정 영역의 구조를 변화시켜 피브릴화를 억제하였으며 또한 효소의 작용에 영향을 주어 감량율을 감소시켰다. 반응성 염료에 의한 가교는 역학적 성질 중 특히 전단강성, 압축에너지, 압축레질리언스를 증가시켰다. 염색후 효소처리한 시료는 다른 시료보다 numeri와 fukurami 값이 높아 더 나은 종합태를 보였다. 공정순서에 따라 약간씩 차이가 있는 촉감을 나타냈다.

• Proceedings of the KIPE Conference
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.341-342
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• 2012

이 논문에서는 모듈 통합형 태양광 전력조절기 시스템을 간소화하기 위해서 인버터 스테이지 DSP에서 도통률을 결정하여 지그비를 이용한 무선방식으로 전송하고 이를 모듈에서 직접 PWM으로 변환하여 전력조절기를 제어하는 직접 PWM 제어방식을 제안하였다. 각 모듈의 전압, 전류를 지그비 모듈을 통하여 일정 간격으로 샘플링하여 그 값을 인버터 스테이지 DSP에 보내주고 MPPT 동작을 통하여 최대전력점에 해당하는 시비율을 컨버터에 다시 지그비 모듈을 통하여 무선으로 보내주는, 전압제어루프를 사용하지 않는 직접 PWM을 이용하여 부스트 컨버터를 제어하는 방법을 사용하였다. 제안하는 방식을 증명하기 위하여 50W 태양광 전력조절기, 듀얼 솔라 PV시뮬레이터 그리고 지그비 모듈을 사용하여 그 타당성을 입증하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제11권9호
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• pp.3406-3411
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• 2010

Assessment of the accommodative response is an essential part of the optometric examination. This study measured objectively the accommodation responses those were measured by Autorefractor, MEM retinoscopy and Nott dynamic retinoscopy, and investigate the correlation and difference the results. Twenty-seven college students with normal visual acuity aged 19 to 29 years (mean $22.7{\pm}2.43$ years) participated in this study. Their accommodative responses to accommodative demand of 4D (25cm) were measured with Shin-Nippon NVision-K 5001 Autorefractor, MEM retinoscopy and Nott dynamic retinoscopy. The accommodative responses to accommodative demand of 4D were $3.70{\pm}0.25D$ by Shin-Nippon NVision-K 5001 Autorefractor, $3.58{\pm}0.30D$ by MEM retinoscopy and $3.77{\pm}0.29D$ by Nott dynamic retinoscopy, respectively. There were high correlations among the three techniques (p<0.05). MEM retinoscopy was measured $0.19{\pm}0.13D$ lower than Nott dynamic retinoscopy (p<0.05) and it was measured $0.12{\pm}0.24D$ lower than Shin-Nippon NVision-K 5001 Autorefractor (p<0.05). There was no significant difference between Nott dynamic retinoscopy and Shin-Nippon NVision-K 5001 Autorefractor (p>0.05). MEM retinoscopy showed lesser accommodative responses than Nott dynamic retinoscopy and Shin-Nippon NVision-K 5001 Autorefractor. Author suggest that Nott dynamic retinoscopy may use Shin-Nippon NVision-K 5001 Autorefractor interchangeably to evaluate accommodative responses expect MEM retinoscopy.

• Journal of the Korea Computer Industry Society
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• 제2권10호
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• pp.1253-1260
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• 2001

In this paper, a new voltage-controlled tunable analog active element for low-voltage applications and information protection is proposed. The proposed active element is composed of the CMOS complementary cascode circuit which can extend transconductance of an element. Therefore, the unity gain frequency which is determined transconductance is increased than that of the conventional element. And then these results are verified by the $0.25\mutextrm{m}$ CMOS n-well parameter HSPICE simulation. As a result, the gain and the unity gain frequency are 42㏈ and 200MHz respectively in the element on 2V supply voltage. And power dissipation of the designed circuit is 0.32mW.

• Proceedings of the Korea Contents Association Conference
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• 한국콘텐츠학회 2005년도 추계 종합학술대회 논문집
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• pp.649-653
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• 2005

To estimate for an error signal with sigmoid nonlinearity what reduced constellation applies closed eye pattern in the initial equalization, there can be improves problems of previous soft decision-directed algorithm that increasing estimate complexity and decreasing of convergence speed when substitute high-order constellation. The characteristic of sigmoid function is adjusted by a mean and a variance parameter, so it depends on adjustment of variance that what reduced constellation $values(\gamma)$ can have ranges between + $\gamma$ and - $\gamma$. In this paper, we proposed Variable Modulus Algorithm (VMA) that can be improving a performance of steady-state by adjustment of variance when equalization works normally and each cluster of constellation decrease.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제34권4C호
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• pp.430-436
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• 2009

In this paper, we propose and describe our implementation of an automatic control system for the center wavelength of a fiber Bragg grating. The proposed system consists of a Fabry-Perot filter and cantilever structure controlled by a step motor interfacing computer. We consider the change of the center wavelength and the reflective spectrum shape for a given FBG according to the translation distance of the push stick and the cantilever thickness variation. The proposed system can control the center wavelength of a FBG with a resolution of 0.01 nm by applying compression or extension to the FBG. The proposed system has characteristics that keep the desired wavelength of the FBG with a variation of environmental conditions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제45권7호
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• pp.77-80
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• 2008

In this paper, low phase noise VCO using novel compact microstrip spiral resonator is proposed. A spiral resonator has super compact dimension, low insertion losses in the passband and high level of rejection in the stopband with sharp cutoff and a large coupling coefficient value, which makes a high Q value, and has reduced the phase noise. To increase the tuning range of VCO, varactor diode has been connected at the tunable negative resistance in VCO. This VCO has presented the oscillation frequency of $5.686{\sim}5.841GHz$, harmonics -29.83 dBc and phase noise of $-115.16{\sim}-115.17dBc/Hz$ at the offset frequency of 100 KHz.