• 한국안광학회지
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• 제11권4호
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• pp.293-298
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• 2006

본 연구는 임상에서 완전자동 및 자동굴절검사기를 자각적 굴절검사와 비교하여 그 유효성과 신뢰성을 평가하였다. 106명(212안)을 대상으로 조절마비를 하지 않은 상태에서 굴절검사를 실시하였으며, 106명의 피검사자를 7일과 14일에 걸쳐 각각 재 측정하여 회차 별 신뢰도를 분석하였다. 자각적 굴절검사와 자동굴절 검사기기별로 측정된 구면굴절력을 대응표본 T-test로 분석하였다.

• 한국자동차공학회논문집
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• 제2권5호
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• pp.48-57
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• 1994

The specific power output and thermal effeciency of any two-stroke engine are dependent on its scavenging behavior. Among the many factors which influence on the scavenging process, the cylinder head shape is one of the important factor. Hence in this study three different type models of cylinder head shape which are the cylindrical, the spherical and the arbitrary shape are studied to show the effects of the turbulent scavenging process in the cylinder with one inlet port, two side ports and one exhaust port. A modified version of KIVA-II which strip out of or add planes of cells across the mesh above the piston for flow simulation of two-stroke engine is used. The $k-{\varepsilon}$ turbulent model is used. The results show that the flow in a two-stroke engine cylinder of the spherical head shape among the three different type model is a desirable for efficient scavenging.

• 전자공학회논문지CI
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• 제43권2호
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• pp.72-80
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• 2006

본 논문에서는 3차원 모델을 검색하기 위한 형태 기반 기술자를 추출하는 새로운 알고리즘을 제안한다. 제안한 형태 기반 기술자는 모델의 기하학적인 특성을 고려하여 레이 캐스팅 샘플링과 구면조화함수를 이용하는 방법이다. 레이 캐스팅 기법은 모델의 외형을 고려한 적응적인 방법으로 샘플링한다. 이 기법을 통해 기술자에 포함되는 형태 정보를 증가시켜 기술자의 식별성을 높인다. 구면조화함수 계수 추출에서는 기하학적인 주파수 특성을 고려하여 적응적인 계수를 추출한다. 이 방법은 검색 성능에 영향을 미치지 않고 기술자를 조밀하고 간결하게 만든다. 최종적으로 두 방법을 결합함으로서 검색 엔진에서 이용가능하고, 식별성이 향상되며 간결해진 기술자를 생성한다.

• 한국수소및신에너지학회논문집
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• 제28권1호
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• pp.40-46
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• 2017

We reviewed the electrical properties of SOFC anode manufactured using spherical Ni and nano YSZ powder. When core-shell is fabricated by using submicron Ni as core and nano-sized YSZ as shell for SOFC anode, the electrical conductivity of the $0.2{\mu}m$ Ni-YSZ core-shell was 3 times higher than that of $1.0{\mu}m$ NiO or $1.0{\mu}m$ Ni-YSZ. Hydrogen selectivity was similar at $800^{\circ}C$, but hydrogen selectivity and methane conversion rate under $750^{\circ}C$ was 10~25% higher, Power density was more than 2 times, ASR was about 1/3, when exposed to $H_2$ atmosphere at $750^{\circ}C$ for a long time, Ni particles did not have any growth or cut off conduction path.

• The Journal of Korean Physical Therapy
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• 제22권1호
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• pp.33-38
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• 2010

Purpose: This study investigated the effect of taping therapy on metacarpophalangeal (MCP) disorders of the thumb. Methods: Twenty eight patients were enrolled in this study. They were randomly assigned to experimental (n=16) or a control group (n=12). The experimental and control groups received Ultrasound (Gymna Pulson 200) operating at a frequency of 3MHz and an intensity of $1.0W/cm^2$ with a 100% duty cycle for 10 minutes. The experimental group received, additionally, taping using Kinesiotape on the injured thumb. The following parameters were measured:pain during rest and flexion of the thumb, tenderness, range of motion (ROM), pinch and spherical grip power pre- and post-treatment. This study was carried out 3 days per week throughout the 2-week treatment. Results: There were significant improvements in pain during rest and flexion of the thumb, tenderness, ROM, pinch and spherical grip power between pre- and post-treatment times in both groups (p<0.05). However, there was a significant difference in all parameters between the experimental and control groups (p<0.05). Finally, the satisfaction level after intervention was significantly higher in the experimental group than in the control group (p<0.05). Conclusion: Taping is effective for treating pain and dysfunction in patients with thumb disorders.

• 한국안광학회지
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• 제20권3호
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• pp.341-347
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• 2015

목적: 가입렌즈 도수 변화에 따른 반응 AC/A비와 프리즘 굴절력 변화에 따른 CA/C비를 측정하고, 이 두 변수와 PD 및 상대조절력과의 상관관계, 반응 AC/A비의 역수와 CA/C비 사이의 평균차이를 비교하여 임상에서 굴절력 및 프리즘 처방의 자료로 활용하고자 한다. 방법: 20대 대학생(평균 $22.62{\pm}2.84$세) 62명(남 50명, 여12명)을 대상으로 주시거리 40 cm에서 하웰시표(Howell card)와 개방형굴절력계(Nvision-K 5001, Shin nippon)를 이용하여 가입렌즈 도수 변화에 따른 반응 AC/A비를 측정하였고, CA/C비는 Wesson fixation card(WFC Bernell, USA) 이면의 DOG시표와 개방형굴절력계를 사용하여 프리즘 굴절력 변화에 따른 CA/C비를 측정하였다. 결과: 가입렌즈 도수 변화에 따른 조절반응량이 프리즘 굴절력 변화에 따른 조절반응량보다 통계적으로 유의한 차이가 크게 나타났다. 동공간 거리와 반응 AC/A비의 설명변량 $R^2=0.025$으로 나타났으며, PD와 CA/C비는 설명변량 $R^2=0.009$으로 나타났다. 상대조절력과 반응 AC/A비의 설명변량 $R^2=0.064$으로 나타났으며 상대조절력과 CA/C비의 설명변량 $R^2=0.321$로 상대조절력과의 예측가능한 상관관계가 있는 것으로 나타났다. 반응 AC/A비와 CA/C비의 설명변량 $R^2=0.126$으로 낮은 상관관계가 있는 것으로 나타났다(p=0.000). 반응 AC/A비의 역수와 CA/C비 사이의 평균차이는 $0.12{\pm}0.06D/{\Delta}$로 통계적으로 유의한 차이를 보였다(p=0.000). 결론: 상대조절력과 CA/C비의 상관관계는 상대조절력이 높은 사람일수록 폭주자극에 대한 폭주성 조절반응량이 큰 것으로 나타났다. 반응 AC/A비의 역수와 CA/C비는 통계적으로 유의한 차이를 보이므로 독립적인 변수로 임상에서 낮은 AC/A비를 가진 환자라도 높은 CA/C비를 가질 수 있다. 이에 양안시 이상에서 프리즘을 처방 할 경우 AC/A비가 정상범위라 하더라도 CA/C비는 다를 수 있어 반드시 조절반응량을 고려한 처방이 되어야 한다.

• 한국안광학회지
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• 제2권1호
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• pp.61-76
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• 1997

18세에서 26세 사이의 남자 64 명, 여자 36명의 안경장용자를 대상으로 나안시력과 타각적 굴정이상, 완전교정도수, 장용감 테스트를 하여 적절한 처방도수를 구했다. 나안시력 0.1을 1.0으로 향상시키기 위해서는 등가구면도수가 남자 -3.00D, 여자 -2.91D 정도가 필요했고, 0.5시력을 1.0.으로 향상시키기 위해서 등가구면도수가 남자 -0.58D, 여자 -1.38D 정도가 필요했다. 나안시력과 교정도수와는 선형적으로 반비례하지는 않았지만 전체적으로 보면 나안시력이 낮을수록 교정에 필요한 교정도수는 증가하는 경향을 보였다. 그리고 타각적 굴절이상치와 완전교정도수, 처방도수를 비교했을 때 타각적 굴절이상치 보다는 완전교정도수가 대체적으로 낮았고, 처방도수는 그보다도 더욱 낮은 도수를 나타냈다. 난시도수는 2.50D 미만이었으며, 도난시 보다는 직난시가 훨씬 많았다. push up법으로 조정력을 측정한 결과 남자는 6.75D~10.04 D, 여자는 7.5D~9.6D까지 분포하고 있었다.

• 한국임상보건과학회지
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• 제8권1호
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• pp.1362-1368
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• 2020

Purpose. In this study, The change of the accommodation function due to the use of a smartphone was objectively evaluated using an Auto Refractokeratometer and was to investigate the effect of accommodation response and microfluctuations of accommodation on stable fatigue. Methods. Twenty subjects (20 males, 20 females) who had no abnormalities in ophthalmic disease and strabismus, diplopia, suppression, convergence and ocular movement, and corrected visual acuity and unaided visual acuity of 0.8 or more were performed. The average age of the participants is (21.78 ± 1.78) years old. The refractive power of the eye was measured using an Auto Refractokeratometer (Speedy-i K-model, Righton Mfg Co. Tokyo Japan), and the equivalent spherical power was automatically calculated from the measured refractive power. The accommodation response amount was calculated for the accommodation stimulation amount in 8 steps in 0.5D increments from + 0.50D to -3.00D in the calculated equivalent spherical power. The microfluctuations of accommodation in the high frequency region was calculated according to the change in the amount of the accommodation stimulus. At this time, the spectral power of the microfluctuations of accommodation was analyzed by Fast Fourier Transformation (FFT). Results. After using the smartphone, it was found that the accommodation response to accommodation stimulation decreased and the microfluctuations of accommodation increased. Conclusions. It can be said that the use of a smartphone affects the accommodation response and the microfluctuations of accommodation, thereby causing a accommodative stable fatigue. Therefore, it is thought that the use of a smartphone for a long time may bring about a change in the accommodation function.

• Journal of Astronomy and Space Sciences
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• 제26권3호
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• pp.287-294
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• 2009

In helioseismology it is normally assumed that p-mode oscillations are excited in a statistically independent fashion. Unfortunately, however, this issue is not clearly settled down in that two experiments exist, which apparently look in discrepancy. That is, Appourchaux et al. (2000) looked at bin-to-bin correlation and found no evidence that the assumption is invalid. On the other hand, Roth (2001) reported that p-mode pairs with nearby frequencies tend to be anti-correlated, possibly by a mode-coupling effect. This work is motivated by an idea that one may test if there exists an excess of anticorrelated power variations of pairs of solar p-modes. We have analyzed a 72-day MDI spherical-harmonic time series to examine temporal variations of p-mode power and their correlation. The power variation is computed by a running-window method after the previous study by Roth (2001), and then distribution function of power correlation between mode pairs is produced. We have confirmed Roth's result that there is an excess of anti-correlated p-mode pairs with nearby frequencies. On the other hand, the amount of excess was somewhat smaller than the previous study. Moreover, the distribution function does not exhibit significant change when we paired modes with non-nearby frequencies, implying that the excess is not due to mode coupling. We conclude that the origin of this excess of anticorrelations may not be a solar physical process, by pointing out the possibility of statistical bias playing the central role in producing the excess.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1839-1844
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• 2003

In order to provide a tool for designing more efficient methods of mixing fabric, a simplified discrete element computational model was developed for modeling fabric dynamics in a rotating horizontal drum. Because modeling the interactions between actual pieces of fabric is quite complex, a simplified model was developed where individual pieces of bundled fabric are represented by spherical particles. The simulations are used to investigate fabric bundle kinematics, the power required to drive the rotating drum, and the power dissipated through normal and tangential contacts. Parametric studies indicate only fill percentage, drum rotation speed, and friction coefficient play significant roles in the fabric bundle dynamics.