• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.147-147
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• 2009

Shadow mask는 OLED의 R-G-B 컬러를 구현하기 위한 유기화합물을 증착하는데 사용하는 금속막으로 수없이 많은 홀이 뚫려있고 디스플레이의 화질, 선명도 및 색상을 좌우하는 핵심적인 소모성 부품이다. 하지만 증착공정시 발생되는 열에 의해 홀의 치수변화가 발생되기 때문에 이를 방지하기 위하여 본 연구에서는 열팽창에 치수변화가 없는 인바소재를 이용하여 Shadow mask를 제조하였다.

• Archives of Plastic Surgery
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• v.35 no.5
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• pp.514-520
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• 2008

Purpose: Many attempts have been made to describe ideal facial proportions for over two thousands year and constantly lasted till now. Dr. Marquardt has derived supposedly ideal facial proportions from the facial golden mask using golden ratio of 1 : 1.618. On the other hand, facial reducing surgeries such as mandible angle reduction are popularized in Asia because the width of mid and lower face of Korean is recognized to be wider. The purpose is to analyze characters of Korean university students' faces in horizontal plane and establish the objective data for facial width distributions and clinical applications. Methods: We applied the facial golden mask to the photographs in 1000 cases, compared the width of mid and lower face between the facial golden mask and Korean university students' faces. And we first calculated the horizontal ratio(HR) of middle and lower face each for using comparative scale of width, facial golden mask. We divided 1,000 cases into 3 groups by degrees of HR and analyzed data of HR on each groups. Using calculated horizontal ratio, we newly invented the cumulative frequency of distribution graphs in Korean university students' faces. Results: Mean data of HR were over 1.0 in all groups, which means that Korean university students' faces are typically wider than facial golden mask in horizontal planes. And this study was statistically significant(p- value < 0.05). Clinically using the cumulative frequency distributions of Korean university students' face width, we can easily explain changes of facial width to patient after facial reducing surgery and describe the changes into objective data. Conclusion: This study concludes thatKorean university students' faces are wider than facial golden mask is significantly true and the cumulative frequency of distribution graphs are expected to be widely used for comparison of results in facial reducing surgery.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.1
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• pp.149-155
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• 2022

Purpose : This study investigated the effects of wearing a mask and different mask filters on the respiratory function of stroke patients. Methods : A total of 15 stroke patients were selected according to the inclusion and exclusion criteria. The respiratory functions were compared between participants with and without masks and among respiratory functions with three different mask filters. The order of using masks was non-wearing masks, Dental masks, KF80 masks, and KF94 masks; the difference in respiratory volumes among these conditions were measured. For accuracy of the measurement, sufficient education on the respiratory measurement method was provided to the researcher, and the heart rate of the participants was estimated to confirm their stability before the measurements. To ensure accuracy, the subjects were educated on the researchers' respiratory measurement methods. Each measurement was followed by 10 min breathing stability before replacing the next mask. Results : The results of this study showed that the difference in respiratory functions, including forced vital capacity (FVC), forced expiratory volume in the first second (FEV₁), and maximal voluntary ventilation (MVV), in stroke patients was statistically significant among different masks (p<.05). Afterwards, the values of FVC, FEV₁, and MVV in stroke patients wearing masks were significantly lower than those of the non-masked control group (p<.05). The difference in respiratory functions with different mask filters showed no statistical significance (p<.05). Conclusion : This study showed that participants wearing any of the masks presented a lower respiratory function than that of those without using masks; additionally, no difference in respiratory functions was observed with differences in mask filters. Therefore, wearing a mask for a prolonged period is confirmed to affect breathing in stroke patients with weak respiratory function.

• Journal of Convergence for Information Technology
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• v.10 no.8
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• pp.77-86
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• 2020

The study aims to analyze the compliance and non-compliance of the Korean health authorities regarding WHO's mask use recommendations following the spread of Covid-19, and to suggest the limitations and implications of the recommendations in the prevention of epidemics by deriving the causes of non-compliance with the results of alternative options. To this end, documents related to masks at home and abroad are reviewed, and WHO's mask recommendations and the Korean health authorities' mask guidelines are targeted for analysis. The analysis results are as follows. First, Korea's health authorities have basically accepted and applied WHO's "limited mask user perspective" in two recommendations. Second, Korea's health authorities have implemented differently from WHO mask recommendations due to the lack of supply and demand of masks. Third, Korea's health authorities were able to succeed in the initial prevention of Corona 19 based on the stabilization of the mask supply. Fourth, in the WHO mask recommendations, mask user restriction resulted in partial errors as a recommendation. The implication derived from the analysis is that even international recommendations based on medical evidence need to be allowed to follow autonomous guidelines according to the country's quarantine situation and competence, rather than strict adherence to international rules, in the infectious disease pandemic situation.

• Journal of Preventive Medicine and Public Health
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• v.31 no.3 s.62
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• pp.440-448
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• 1998

In many developed countries, for example, USA, respirator fit testing is required before entering specific work environment to ensure that the respirator worn satisfies a minimum of fit and that the user knows when the respirator fits properly. Unfortunately because we have not fit test regulation in Korea, a lot of workers wearing respirators may be potentially exposed to hazards. This study was conducted to evaluate the fitting performance for respirators and correlation fit factors with facial dimensions of wearers. 110 subjects (70 males, 40 females) were fit tested for three quarter masks, i.e., two domestic-made Mask 2, and Y and one foreign-made Mask T using PortaCount 8020. A facial dimension survey of the same subjects was conducted to develop a facial dimension grids fer correlation fit factors with facial dimension parameters. A facial dimension grid was developed on the basis of face length and lip length for quarter masks. The results obtained were as follows : 1 Fit factors of Mask T were much higher than those of Masks Z, and Y. 2. Males were fitted more properly than females. 3. Male in box 'f' of grid would be adequately fitted Mask Y and male in box 'b', 'e', 'f', 'h' of grid would be sufficiently fitted Mask T. Female in box 'h' of grid may have a good fitting performance for both Mask Y, and T. But subjects in all boxes of grid would be inadequately fitted Mask Z.

• Journal of the Semiconductor & Display Technology
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• v.15 no.2
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• pp.32-37
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• 2016

Sidewall angle (SWA) of an absorber stack in extreme ultraviolet lithography mask is considered to be $90^{\circ}$ ideally, however, it is difficult to obtain $90^{\circ}$ SWA because absorber profile is changed by complicated etching process. As the imaging performance of the mask can be varied with this SWA of the absorber stack, more complicated optical proximity correction is required to compensate for the variation of imaging performance. In this study, phase shift mask (PSM) is suggested to reduce the variation of imaging performance due to SWA change by modifying mask material and structure. Variations of imaging performance and lithography process margin depending on SWA were evaluated through aerial image and developed resist simulations to confirm the advantages of PSM over the binary intensity mask (BIM). The results show that the variations of normalized image log slope and critical dimension bias depending on SWA are reduced with PSM compared to BIM. Process margin for exposure dose and focus was also improved with PSM.

• The Korean Journal of Emergency Medical Services
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• v.22 no.1
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• pp.73-82
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• 2018

Purpose: The purpose of this study was to compare the tidal volumes and airway pressures of 3 mask-sealing methods (one hand C-E, two hands C-E, and one hand O-E) for ventilation treatment. Methods: The study subjects were 45 paramedic students. Tidal volume was measured for the three sealing methods by setting a ventilator, connecting it to the masks for 2 minutes, and using Respi-trainer software. Results: Regarding general characteristics, the group of men, in upper grades, and with practical training experience and experience and experience in the implementation of bag-valve-mask ventilation provided higher tidal volumes. Regarding physical characteristics, larger hands and greater grip strength correlated with higher tidal volume. Two hands C-E generated the highest tidal volume of $483.78{\pm}34.14mL$, one hand O-E generated $449.59{\pm}51.09mL$ and one hand C-E generated $394.31{\pm}68.95mL$. Conclusion: Means of tidal volumes were statistically significantly different based on mask sealing methods (p<.001). Two hand C-E was performed by the two-persons task and was suggested as the most effective method. For the one-person task, one hand O-E was the more effective method compared to the previous one hand C-E.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1151-1152
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• 2003

Harmonic analysis, based on finite element method, is popularly used to predict a response of shadow mask to the external excitation from speakers. Since vibration wave travels from speakers to the shadow mask, a finite element model must include all mechanical parts between the speakers and the shadow mask, which increases total time needed in finite element modeling and computation. In this paper, we perform the harmonic analysis on a MF assembly to obtain frequency response function of a shadow mask, and compare the solutions with experimental results.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.8
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• pp.1247-1256
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• 1989

In this paper, we propose the dynamic scene segmentation algorithm using a cross mask and edge information. This method, a combination of the conventioanl feature-based and pixel-based approaches, uses edges as features and determines moving pixels, with a cross mask centered on each edge pixel, by computing similarity measure between two consecutive image frames. With simple calcualtion the proposed method works well for image consisting of complex background or several moving objects. Also this method works satisfactorily in case of rotaitional motion.

• Journal of Korean Academy of Nursing
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• v.51 no.5
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• pp.549-560
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• 2021

Purpose: This study evaluated the validity and reliability of the Korean version of the Face Mask Use Scale (K-FMUS) among community-dwelling adults. Methods: The participants of the study were community-dwelling adults in Korea using face masks during the COVID-19 pandemic. The English FMUS was translated into Korean using forward and backward translation procedures. The construct validity and reliability of the K-FMUS were evaluated using the exploratory and confirmatory factor analyses and the internal consistency reliability test. Results: The K-FMUS comprised 6 items divided into 2 factors. The variance of the factors was approximately 79.1%, which suggested that the scale indicated the effectiveness of face mask usage. The two factors were labeled as face mask use in society (4 items) and face mask use at home (2 items). Cronbach's α value for the overall scale was .88. Conclusion: The K-FMUS is a valid and reliable scale that can be used to measure face mask usage among community-dwelling adults in Korea during the COVID-19 pandemic.