• Journal of Periodontal and Implant Science
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• 제28권2호
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• pp.371-376
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• 1998

This study presents an evaluation of the effectiveness of nonsurgical subgingival scaling and root planing related to initial pocket depth, type of teeth, and individual root surfaces. A total of 110 teeth designated for periodontal surgery in 67 patients with marginal periodontitis were selected and received thorough scaling and root planing with standard rigid Gracey curettes. After a healing period of 4 to 8 weeks, residual calculus was assessed at the time of periodontal surgery following the reflection of mucoperiosteal flap. The results demonstrated a high correlation between the percentage of residual calculus and initial pocket depth. It was further noted that tooth type and involved root surface also influenced the rate of calculus remnant. The results of this study suggest that complete removal of subgingival calculus utilizing conventional instrumentation via closed approach is rare.

• 제어로봇시스템학회논문지
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• 제6권1호
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• pp.91-97
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• 2000

In this paper, the illuminator is designed to recognize the shape and the existence of holes of radiation fin in the point that the light reflection characteristics are different according to the roughness of the material. The threshold value, the positions of holes and the black pixel nembers in the positon are obtained under the illuminator, in accordance with the reference image, by applying binary conversion and hole segmentation algorithm, as they are suggested in this paper, The existence and shape of hole are recognized by calculating the distance and feature value in the test image, which is obtained from the parameters of reference image. It is programmed to apply to GUI(Graphic User the Interface) in windows. More than 98% of recognition rate is shown, as it is applied to three different sizes of the radiation fin.

• 한국인쇄학회지
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• 제1권1호
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• pp.7-41
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• 1983

Reproduced colors which are half-tone printed at the rate of 10,20,30, ...100% half-tone dot area by each process ink- cyan, magenta, yellow and at the rates of 0,30,60, 100% half-tone dot areas by the mean color mixing of black, cyan, magenta and yellow, are colorimetric analyzed by make use of the 1931 CIE XYZ system of color specification and matching the Munsell color system. Espacially, magenta and secondary colors which are contained magenta, do not have good uniformity and proportionalization in the dominant wavelength and the excitation purity. Half-tone colors without reflection of blue light, are reproduced ideal color with the excitation purity 100% in wavelengths from 555nm to 600nm.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.227-232
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• 2003

Anodizing film was prepared by anodic oxidation of pure aluminum(purity > 99.50) using DC power supply for constant current mode in an electrolytic solution of surface of sulfuric acid. Effects of pre-treatment process such as chemical polishing, acid cleaning, alkali etching before anodic oxidation, were studied to microstructures and surface morphologies. A roughness on surface of anodizing film had to be decreased for amorphous phase by anodic oxidation. A roughness on surface of anodizing film decrease as annealing temperature increased in chemical polishing.

• 한국실내디자인학회논문집
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• 제5호
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• pp.30-36
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• 1995

Light plays an important role in making a continuity of space and in determining the distinctive expression and char-acter of a space. Particularly, the introduction of natural light derives from our esthetic needs, as well as from the fundamental biologi-cal necessities of human beings. And also, adaptation to time and space is the vital factor of human survival and prosperity. Our visual recognition of light is usually formed not only by practical illumination but by analogy, expection and expe-rienced of lighting itself. As the forecase of natural light is (almost) impossible be-cause of variables such as changing weather, reflection rate of light and the patterns of shade, in designing the introduc-tion of daylight, there should be follow-ed careful considera-tion of the adaptation to such variety and the impet-us of light. The research was conducted to mane a contribution to cre-ate more rich and beautiful interior spaces by studying the characteristic of light which is one of the important factors of interior space design, and by inquiring the way to intro-duce light and its effect through the practical examples of Alvar Aalto, Le Corbusier and Louis I. Kahn.

• 대한금속재료학회지
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• 제50권5호
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• pp.389-393
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• 2012

Improvement in microwave absorbance has been investigated by insertion of a periodic air cavity in rubber composites filled with magnetic powders. A mixture of $Co_2Z$ hexagonal ferrite and Fe powders were used as the absorbent fillers in silicone rubber matrix. The complex permeability and complex permittivity of the magnetic composites were measured by reflection/transmission technique. In the grid-type magnetic absorbers, the equivalent permeability (${\mu}_{eq}$) and permittivity (${\varepsilon}_{eq}$) are calculated as a function of air volume rate (K) on the basis of effective medium theory. Reduction in the material parameters (especially, dielectric permittivity and magnetic loss) has been estimated with the increase of K. Plotting the ${\mu}_{eq}$ and ${\varepsilon}_{eq}$ on the solution map of wave-impedance matching, wide bandwidth microwave absorbance has been predicted in the magnetic composites with an optimum value of K.

• 한국분무공학회지
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• 제26권4호
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• pp.182-188
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• 2021

In this paper, using a transfer function-based analytical model, major factors influencing the acoustics and combustion instability in a two-stage duct system composed of a nozzle and a combustor were derived and their quantitative effects were evaluated. From the acoustic analysis, it was confirmed that the change in reflection coefficient and mean flow could have a great influence on the instability growth rate, and the area ratio and speed of sound ratio between the nozzle and the combustor are also key parameters to determine combustion instability as well as flame transfer functions.

• 산업경영시스템학회지
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• 제46권2호
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• pp.32-46
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• 2023

Recently, small and medium-sized manufacturing companies have shown increased interest in and participation in smart factories in order to survive in market competition. However, many SMEs build smart factories without a systematic review or preparation, which leads to them not being able to use them properly. This study considers the main reason for the low utilization rate of smart factories to be a lack of sufficient reflection of user requirements. Therefore, a method and procedure for deriving the priority of smart factory requirement functions and operating performance indicators based on QFD is proposed as a solution to this issue.

• 대한전자공학회논문지TC
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• 제41권8호
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• pp.93-97
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• 2004

전력선 통신의 매체인 전력선은 60Hz 전력 공급을 위해 설계되었기 때문에 고속 전력선 통신을 위한 1MHz∼30MHz 대역에서는 전력선은 전기적으로 많은 다른 특징을 갖는다. 따라서 고속 전력선 통신을 위해서는 전력선의 고주파 특성-감쇄 지연, 임피던스-등이 자세하게 분석되고 연구되어야 한다. 본 논문에서는 고속 전력선 통신용 1MHz∼30MHz 주파수 대역 옥내저압 전력선 (220V) 임피던스를 측정하였다. 벡터 회로망 분석기와 저압 전력선 결합 장치(coupling unit)를 이용하여 임피던스를 측정하였다. 결합 장치를 T형 등가회로로 바꾸어, 전체 회로에서 얻은 산란계수를 이용하여 저압 전력선 임피던스를 구했다. 제안된 방법으로 표준 한국형 저층 연립 아파트에 대한 임피던스를 측정하고, 그 특성을 분석하였다. 또한 임피던스 정합을 위하여 평균 임피던스를 구하였고, 측정결과 평균 임피던스는 약 100Ω이었다.

• 한국음향학회지
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• 제32권2호
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• pp.95-103
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• 2013

천해에서 수중음향통신은 해면과 해저의 음향특성에 강한 영향을 받는다. 시변적인 해면 산란과 입사각에 좌우되는 해저손실에 의해 수중통신 시스템의 성능은 영향을 받게 되어 고속의 디지털 통신 성능은 저하된다. 우세한 직접파가 존재하면 통신채널은 Rice 페이딩, 그렇지 않은 경우 Rayleigh 페이딩으로 모델링된다. 그러나 실해역의 실험으로 이러한 통계적인 채널 모델링을 검증하는 것은 어려운 연구주제로 알려져 있다. 해면산란과 해저반사 손실이 수중음향통신에 미치는 영향의 근원적인 이해를 돕기 위하여 저자들은 이들의 영향을 정량화하기 위한 천해 해역에서 실험을 수행하였다. 이진 주파수 천이 변조 방식으로 영상을 전송하여 해면산란과 해저 입사각에 좌우되는 해저반사 영향을 송신기와 수신기간의 거리, 수신기 깊이에 따른 영상의 양호성과 비트 오류율로 평가하였다. 결론적으로 영상의 전송 성능은 채널의 일관성 대역폭을 결정하는 송수신기간의 거리 및 수신기의 깊이에 좌우된다.