• Current Optics and Photonics
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• 제7권1호
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• pp.1-14
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• 2023

Wavefront-coding imaging can achieve high-quality imaging along with a wide range of defocus. In this paper, the anti-laser detection and damage performance of wavefront-coding imaging systems using different asymmetric phase masks are studied, through modeling and simulation. Based on FresnelKirchhoff diffraction theory, the laser-propagation model of the wavefront-coding imaging system is established. The model uses defocus distance rather than wave aberration to characterize the degree of defocus of an imaging system. Then, based on a given defocus range, an optimization method based on Fisher information is used to determine the optimal phase-mask parameters. Finally, the anti-laser detection and damage performance of asymmetric phase masks at different defocus distances and propagation distances are simulated and analyzed. When studying the influence of defocus distance, compared to conventional imaging, the maximum single-pixel receiving power and echo-detection receiving power of asymmetric phase masks are reduced by about one and two orders of magnitude respectively. When exploring the influence of propagation distance, the maximum single-pixel receiving power of asymmetric phase masks decreases by about one order of magnitude and remains stable, and the echodetection receiving power gradually decreases with increasing propagation distance, until it approaches zero.

• 공연문화연구
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• 제41호
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• pp.257-284
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• 2020

고성오광대는 1950년대 말부터 학술조사가 시작되어 1964년 국가무형문화재로 지정되었다. 지정 당시까지는 종이탈을 사용하였으나 1965년에는 이미 나무탈로 바뀌었으며 이후 탈의 변화 양상이 매우 크다. 1960년에는 9개의 탈을 사용하였는데 문둥이, 초란이, 말뚝이, 청보양반, 젓양반, 할미, 제밀주 탈을 기본으로 하였으며 여기에 소무는 제밀주와, 청보양반과 비비양반은 영감과 탈을 겸용하기도 하였다. 황봉사와 상주는 탈을 쓰지 않고 맨얼굴로 등장했다. 1965년부터 고성오광대 연희용 탈은 전체가 나무탈로 바뀌었다. 상주, 마당쇠, 상두꾼을 제외한 전 배역이 탈을 쓰고 있는데 비비, 홍백양반, 봉사 탈은 1964년까지는 등장한 적이 없는 탈이다. 초라니는 종가도령으로 바뀌었고 청보양반은 원양반으로 대체되었다. 1969년을 기점으로 연희용 탈은 종류가 현재와 같아지는 안정기에 들어선다. 비비양반과 소무를 제외한 모든 등장인물들이 개별탈을 사용하여 총18점의 탈을 사용한다. 양반들은 적제양반까지 확실하게 분화되어 총 7명의 양반이 등장한다. 이렇게 탈의 종류와 재질 및 표현법에 변화가 큰 것은 1세대 탈 제작자가 사망하면서 탈 제작의 전승이 끊어진 이유도 있겠으나 지정 이후 연희자들이 맞닥뜨려야 했던 연희환경의 극심한 변화에도 그 원인이 있다. 연희자들의 자족적인 놀이였기 때문에 세부 사항에서는 엄격한 규칙이 적용되지 않는 유동적인 놀이였으나 민속예술경연대회에 참가하면서 점차 공연을 위한 준비로 바뀌었다. 춤이나 의상, 소품들도 점차 화려해졌고 시각적인 효과와 짜임새 있는 연출을 시도하면서 연희 전반의 변화와 함께 탈의 변화를 가져왔고 이를 보존회 내부에서도 수용하게 되었다.

• Journal of Preventive Medicine and Public Health
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• 제31권3호
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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.

• 복식문화연구
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• 제19권3호
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• pp.460-472
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• 2011

This paper developed motifs through the use of images of masks with which the Korean innate consciousness of aesthetics is expressed. The motifs were applied to fashion items. This paper investigated the concept, origin and types of traditional masks through the existing literature. Using the computer graphic programs of Illustrator and Photoshop CS2, three basic motifs were set from the images of the nobleman, Bune of Hahoi Tal and Byeongsan Tal. Each motif was extended into two motifs by changing shape and color. For the basic motif design, this study sought to express contemporary images, suitably for each fashion item, while maintaining the basic shape of the masks and their traditional images. In addition, this study set the concept of the design so that could be accepted by various age groups. For the design of handkerchiefs, a rotating array, involving enlargement, reduction, repetition, and the gradation of motifs, as well as a diagonal symmetric array, and all-over patterns were developed. The T-shirt design created here was divided into a half-sleeve box type, a round neckline sleeveless type, a V-neckline close-fitting sleeveless type, and a V-neckline close-fitting cap sleeve type. For the design of necklaces, OLED or LED, which are considered as a future display type, was used. Additionally, the production of an entertainment styled new atmosphere is proposed.

• 한국산업보건학회지
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• 제15권3호
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• pp.277-281
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• 2005

Air-line mask is an important personal protective equipment for workers working under hazardous surroundings in which a fixed ventilation system is difficult to be installed. If the air-line mask make loud noise, works wearing the mask may be faced with health problems such as noise induced hearing loss(NIHL). The purpose of this study is to introduce a low noisy technology for workers using air-line mask. A traditional type air-line has been improved to an advanced air-line mask with lesser noise. In the mask, air suppling conduits consists of multi tubes are placed inside of the front of the safety helmet. The noise level reduced from 80dB(A) to less than 80dB(A) when measured by KS A 0701 method at Center for Safety Inspection, Testing and Certification for KOSHA. It is suitable for related regulation[Article 35 of the Industrial Safety and Health Act(Test of Personal Protective Equipment)]. While workers working in noise level of over 90dB(A), they may expose to 82dB(A) or less when they wear the advanced masks. This type masks can be an alternative for works suffering from loud noise generated by traditional air-line masks.

• 한국산업보건학회지
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• 제26권3호
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• pp.367-376
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• 2016

Objectives: The production and use of nanoparticles have been increased. In 2014 Workplace Survey Results, 335 companies produce and treat nanoparticls. However, lack of data on nano-toxicity and a method for risk management and regulation on nanoparticles and the standard test method are not sufficient. Protective equipment selection guidelines for nanoparticles are not established. It is required to carry out respirator efficiency test against nanoparticles. This study was performed to evaluate filtration efficiency and manikin-based total inward leakage of particle filtering mask using in Korean country challenged with silver nanoparticles. Methods: We investigated filtration efficiency and total inward leakage of 7 respirator with silver nanoparticle. Results: The geometric mean diameters of Silver nanoparticles were 30 nm and number concentration were about $10^6{\sharp}/cm^3$. Filtration efficiency of six of the seven particle filtering masks was more than 98% and one particle filtering masks filtration efficiency was 94.9%. The filtration efficiency of particle filtering masks to 20 nm silver nanoparticels was highest. Artificial breathing machine with manikin based total inward leakage were 7.6% ~ 42.3%. Conclusions: The results of this study nano-silver filter efficiency was high but the total inward leakage was higher than filter penetration. Therefore, education on how to wear a respirator should be demanded. Especially for workers handling nanoparticles and toxic material, user seal checking and fit test must be performed.

• 복식문화연구
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• 제10권4호
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• pp.404-418
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• 2002

The pattern of a dance had changed and made a progress delicately according to the change of the myth, religion, and civilization. One genre which had experienced the change for the dance is a mask dance. This dance started from wishes to adore spirit or god with imitated masks of native animals and desire to identify with nature. After the middle ages, it finally became to approach to the artistic state. In that dance, there was used a role of the head of the family which was strongly adapted to the shape of the mask as performing casts After studying symbolic characteristics of the mask dancing, we could conclude these as fol1ows.: First, Masks symbolized the totemism that adores spirit or god. This kind of whole masks were consistently used. Second, Mask was worn for expressing a dancer's cast well. This function of performing cast was in the primitive ages. However at the age which was characterized as the age of the art, the expression of using a mask became various. Third, Mask was mostly related to the head of the family and appeared with the desire to be others not themselves. Since the middle ages, this tendency continued to the modern dance. Now we can see this type at the carnival. The mask was not only an effective means of dance but also an expression of totemism, performing cast, and the head of the family. Therefore it contributed to the growth of the dance a lot.

• 대한치과기공학회지
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• 제11권1호
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• pp.95-102
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• 1989

This study was performed to study the efficiency of a local ventilation system, installed in dental laboratories, and of two types of protecting face masks. The dust originating from the workpiece as well as from the wheels and stones was collected on air filters in the cutting cycle during coarse and fine grinding, and in the subsequent polishing procedures of each specific dental material. The efficiency of the ventilation system was measured on the basis of weight reduction of dust in the breathing air at a distance about 20-40 cm from workpiece. The results were as follows: 1. Use of the local ventilation system reduced the amounts of respirable dust to an average level of 21.4%, although the efficiency of the local ventilation system varied depending upon materials used. 2. Mounting a nozzle on the tube improved the efficiency of the ventilation system considerably. The efficiency of the local ventilation system also increased as the workpiece was closing to the tube inlet. 3. With or without the local ventilation system, the distance between the position of the workpiece and sampler greatly affected the dust level. 4. The face masks covering the sampler improved the efficiency of the ventilation system considerably.

• 로봇학회논문지
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• 제14권1호
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• pp.31-39
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• 2019

A robot usually adopts ANN (artificial neural network)-based object detection and instance segmentation algorithms to recognize objects but creating datasets for these algorithms requires high labeling costs because the dataset should be manually labeled. In order to lower the labeling cost, a new scheme is proposed that can automatically generate a training images and label them for specific objects. This scheme uses an instance segmentation algorithm trained to give the masks of unknown objects, so that they can be obtained in a simple environment. The RGB images of objects can be obtained by using these masks, and it is necessary to label the classes of objects through a human supervision. After obtaining object images, they are synthesized with various background images to create new images. Labeling the synthesized images is performed automatically using the masks and previously input object classes. In addition, human intervention is further reduced by using the robot arm to collect object images. The experiments show that the performance of instance segmentation trained through the proposed method is equivalent to that of the real dataset and that the time required to generate the dataset can be significantly reduced.

• 한국의상디자인학회지
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• 제23권2호
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• pp.93-104
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• 2021

The worldwide coronavirus pandemic has brought to light the importance of having a reliable supply of masks for each person. This study aims to understand the effect of personal awareness (including community, others', and safety awareness) on consumption conformity and the repurchase intention of masks. The research method used the SPSS 22.0 and AMOS 22.0 statistical systems to analyze descriptive statistics in terms of reliability, validity, structural equation modeling, and moderated regression analysis. A total of 272 Chinese participants were recruited via an online survey website (www.sojump.com) from May 1 to May 14, 2020. Findings indicated that mask users' awareness can be categorized into three distinct types: community, others', and safety awareness. The more community and safety awareness is perceived, the higher the level of consumption conformity. In contrast, others' has no statistical effect on consumption conformity or repurchase intention. The positive influence of consumption conformity on the repurchase intention of masks is also weaker than price perception. However, another moderating variable, mask quality, has no moderating effect. The results of this study can help mask manufacturers and distributors retain their customers, resulting in reasonable protective measures while maintaining market order. Theoretical and managerial implications for mask suppliers are also provided.