• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.7
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• pp.37-41
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• 2004

We have formulated an empirical analytic model for the static characteristics of implanted vertical-cavity surface-emitting lasers (VCSELs). Specifically, we have derived analytic formulas for the threshold current, slope efficiency, dynamic resistance, and the output power and forward voltage at the operation current of 12 ㎃ in terms of the implant and metal-aperture radii by fitting the measured results. The radii of the metal aperture and implant mask of the 850 nm VCSELs range from 4 to 12.5 ${\mu}{\textrm}{m}$ and 7 to 17.5 ${\mu}{\textrm}{m}$ respectively. The model shows the way of tailoring the VCSEL characteristics by changing the mask dimensions only.

• Journal of the Semiconductor & Display Technology
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• v.18 no.2
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• pp.44-47
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• 2019

Amorphous carbon layer (ACL) is actively used as an etch mask. Recent advances in patterning ACL requires the next level of durability of hard mask in high aspect ratio etch in near future semiconductor manufacturing, and it is worthwhile to know the surface property of ACL thin film to enhance the property of etch hard mask. In this research, ACL are deposited by 6 inch plasma enhanced chemical vapor deposition system with $C_3H_6$ and $N_2$ gas mixture. Surface properties of deposited ACL are investigated depending on gas flow, pressure, RF power. Fourier transform infrared is used for the analysis of surface chemistry, and X-ray photoemission spectra is used for the structural analysis with the consideration of the contents of $sp^2$ and $sp^3$ through fitting of C1s. Also mechanical properties of deposited ACL are measured in order to evaluate hardness.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.1
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• pp.94-104
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• 2021

Objectives: A number of medical institutions have been conducting fit tests to perform seal checks on masks. This study aimed to compare the differences fit factor before and after domestic N95 mask-wearing training through a fit-test. Methods: A survey of 59 healthcare workers was conducted regarding whether they had undergone a fit test or received training on mask-wearing. Further, the fit of two types of domestic N95 masks was measured before and after the training using a QNFT(Quantitative Fit test). The average fit factors before and after training were compared using a paired t-test. Additionally the differences in the fit test pass rate were analyzed using a McNemar test. Results: A statistically significant difference was seen between the fit factors in the fit tests conducted before and after the training (p=0.0015), as well as in the fit of the two types of masks tested (p<0.01). Thus, an improvement in mask fitting was seen after the training, even with differently fitted masks. Conclusions: Upon using a QNFT, a significant increase in the fit factors for N95 masks was observed after training compared with masks that were fitted as usual. This highlights the importance of training in mask-wearing, with the conclusion that training healthcare providers will improve the fit of masks.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.79-89
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• 1999

A quantitative fit test, condensation nuclei counting (Portacount 8025, TSI), was performed concurrently with a banana oil (isoamyl acetate: IAA) qualitative fit test (MSA) to evaluate reliability on IAA QLFT and correlation between two methods. One brands of quarter mask (3M model 7500 medium) was prepared for QLFT with HEPA filter and gas & vapor removing media, i.e., combination cartridge. 110 subjects (65 male, 45 female) were fit tested QNFT and QLFT each three times. For a wearer combination having a FF<10, as determined by CNC QNFT, the point es timate (${\beta}$-error) of the probability of that combination not being rejected by the banana oil QLFT was found to be 0.0 with 95% confidence that this statistic is not expected to exceed 0.15. For a wearer combination having a FF<100, as determined by CNC QNFT, the point estimate of the probability of that combination not being rejected by the banana oil QLFT was found to be 0.07 with 95% confidence that this statistic is not expected to exceed 0.13. The uncertainty associated with each estimate, however, is large due to the small number of study subjects with inadequately fitting respirators.

• The Research Journal of the Costume Culture
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• v.19 no.3
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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.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.135-144
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• 2015

Fingerprint pores have proven to be useful features for fingerprint recognition and several pore-based fingerprint recognition systems have been reported recently. In order to recognize fingerprints using pore information, it is very important to extract pores reliably and accurately. Existing pore extraction methods utilize 2D model fitting to detect pore centers. This paper proposes a pore extraction method using 1D Gaussian model which is much simpler than 2D model. During model fitting process, 1D model requires less computational cost than 2D model. The proposed method first calculates local ridge orientation; then, ridge mask is generated. Since pore center is brighter than its neighboring pixels, pore candidates are extracted using a $3{\times}3$ filter and a $5{\times}5$ filter successively. Pore centers are extracted by fitting 1D Gaussian model on the pore candidates. Extensive experiments show that the proposed pore extraction method can extract pores more effectively and accurately than other existing methods, and pore matching results show the proposed pore extraction method could be used in fingerprint recognition.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.99-112
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• 1997

A quantitative fit test, condensation nuclei counting(Portacount 8025, TSI), was performed concurrently with a qualitative fit test, sodium saccharin(FT-10, 3M) to evaluate FF values and to determine the correlation between two methods. Two brands of full facepieces, T, S and two brands of half masks, T, S, were fit tested, respectively, on 103 wearers one time. The FF values obtained by CNC QNFT were lognormally distributed. The FF values for T brand of respirators were statistically very much higher than those for S brand of respirators. For a full facepiece wearer combination having a $FF{\leq}100$, as determined by CNC QNFT, the point estimate of the probability of that combination not being rejected by the saccharin QLFT was found to be 0.09 with 90% confidence that this statistic is not expected to exceed 0.25. For a half mask wearer combination having a $FF{\leq}10$, as determined by CNC QNFT, the point estimate of the probability of that combination not being rejected by the saccharin QLFT was found to be 0.10 with 90%, confidence that this statistic is not expected to exceed 0.23. The uncertainty associated with each estimate, however, is large due to the small number of study subjects with inadequately fitting respirators. This result indicates that saccharin QLFT may be more suitable for adequately fitting respirators than inadequately fitting respirators.

• ETRI Journal
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• v.7 no.3
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• pp.3-11
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• 1985

CAD tools that has the common data base system are important to design for the VLSI. Each CAD tools are used to design for the VLSI, and to reduce the complexity, man-error, design-time for the IC design. CIF, a layout description language, was proved to be effective in this point. In this article, the program which translates pattern generation data for the mask tooling into CIF data was described. This program has its character in the unification of physical design data base for a design automated CAD system. The output format of CIF data is fitting to the input of the kgraph that is graphic layout editor, and the name of each layer and the output file is extended as a user's option.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.2
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• pp.120-130
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• 2007

A oxygen generating closed-circuit SCBA for escape from fire will be newly developed and then a program for estimating service time for it should be required. A SCBA made on an experimental basis consisted of five components such as half facepiece (mask), $KO_2$ box, oxygen reservoir, $CO_2$ remover and hood. The half mask had a good fitting performance since fit factors for 10 subjects were all above 100. It was found that height of subjects should be the best variable to estimate service time. Measured service time was inversely correlated with height of subjects. Service life time could be estimated by interpolation and extrapolation using inverse relationship between height and measured service time, for example, 28 minutes for male and female of 170 cm during resting, 10 minutes at the walk of 4 km/h and 5 minutes at the walk of 6 km/h considering safety margin of 20%. The study implies that program for estimating service time for the SCBA should require subject's height, speed of walk (4 km/h and 6 km/h) and fit testing. Considering safety margin, selecting younger subjects would be better. The study on the number of subjects and selecting facial dimensions should be more needed for the final program.

• Safety and Health at Work
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• v.10 no.3
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• pp.275-304
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• 2019

Background: Air-purifying, tight-fitting facepieces are examples of respiratory protective equipment and are worn to protect workers from potentially harmful particulate and vapors. Research shows that the presence of facial hair on users' face significantly reduces the efficacy of these devices. This article sets out to establish if an acceptable seal could be achieved between facial hair and the facepiece. The team also created and investigated a low-cost "pressure testing" method for assessing the efficacy of a seal to be used during the early design process for a facepiece designed to overcome the facial hair issue. Methods: Nine new designs for face mask seals were prototyped as flat samples. A researcher developed a test rig, and a test protocol was used to evaluate the efficacy of the new seal designs against facial hair. Six of the seal designs were also tested using a version of the conventional fit test. The results were compared with those of the researcher-developed test to look for a correlation between the two test methods. Results: None of the seals performed any better against facial hair than a typical, commercially available facepiece. The pressure testing method devised by the researchers performed well but was not as robust as the fit factor testing. Conclusion: The results show that sealing against facial hair is extremely problematic unless an excessive force is applied to the facepiece's seal area pushing it against the face. The means of pressure testing devised by the researchers could be seen as a low-cost technique to be used at the early stages of a the design process, before fit testing is viable.