• Fashion & Textile Research Journal
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• v.22 no.6
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• pp.826-833
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• 2020

When it is necessary to wear masks for long periods, such as during the current COVID-19 pandemic, the essential function of masks to prevent contamination (or transmission to others) as well as comfortableness are important. For this study, we used three-dimensional (3D) facial measurements of adult women to compile basic face shape data for designing comfortable and effective masks. This study analyzed the 3D facial data of 127 subjects in their 20s to 30s of the 6th Size Korea. Factor analysis of the survey data produced seven factors that formed the composition of adult female faces. These factors combined to produce three facial types: square (long face and a large lower middle face), oval (smallest central and lower body in the middle), and triangle (short face with a small central and lower large nose). These types reflect that the facial types of adult women show the differences in the nose angle, nose length, bitragion-subnasal arc, bitragion-menton arc. Therefore, properly fitting masks for fine dust particle filtration require 3D customization of a mask's breathing apparatus to fit differently shaped central and lower face parts that interfere with mask fit.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.2
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• pp.257-264
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• 2020

Vectorization is currently the main method in feature collection (extraction) during digital mapping using UAV-Photogrammetry. However, this method is time consuming and prone to gross elevation errors when extracted from a DSM (Digital Surface Model), because three-dimensional feature coordinates are vectorized separately: plane information from an orthophoto and height from a DSM. Consequently, the demand for stereo plotting method capable of acquiring three- dimensional spatial information simultaneously is increasing. However, this method requires an expensive equipment, a Digital Photogrammetry Workstation (DPW), and the technology itself is still incomplete. In this paper, we evaluated the accuracy of low-cost stereo plotting system, Menci's StereoCAD, by analyzing its three-dimensional spatial information acquisition. Images were taken with a FC 6310 camera mounted on a Phantom4 pro at a 90 m altitude with a Ground Sample Distance (GSD) of 3 cm. The accuracy analysis was performed by comparing differences in coordinates between the results from the ground survey and the stereo plotting at check points, and also at the corner points by layers. The results showed that the Root Mean Square Error (RMSE) at check points was 0.048 m for horizontal and 0.078 m for vertical coordinates, respectively, and for different layers, it ranged from 0.104 m to 0.127 m for horizontal and 0.086 m to 0.092 m for vertical coordinates, respectively. In conclusion, the results showed 1: 1,000 digital topographic map can be generated using a stereo plotting system with UAV images.

• Geophysics and Geophysical Exploration
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• v.4 no.2
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• pp.25-33
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• 2001

Loop-loop electromagnetic (EM) survey in frequency domain has been carried out in order to provide basic solution to geotechnical applications. Source and receiver configuration may be horizontal co-planar (HCP) and/or vertical co-planar (VCP). Three quadrature components of mutual impedance ratio for each configuration are used to construct the subsurface image. For the purpose of obtaining the model response and validating the reasonable performance of the inversion, we obtained each responses of two-layered and three-layered earth models and two-dimensional (2-D) isolated anomalous body. The response of 2-D isolated anomalous body has been calculated using extended Born approximation for the solution of 2.5-D integral equation describing EM scattering problem. As a result of the least-squares inversion with variable Lagrangian multiplier, we could construct more resolvable image from HCP data than VCP data. Furthermore, joint inversion of HCP and VCP data made better stability and resolution of the inversion. Resistivity values, however, did not exactly match the true ones. Loop-loop EM field data was obtained with EM34-3XL system manufactured by Geonics Ltd. (Canada). Electrical resistivity survey was conducted on the same line for the comparison in advance. Since the constructed image from loop-loop EM data by 2-D inversion algorithm showed almost similar resistivity distribution to that from electrical resistivity one, we expect the developed 2.5-D loop-loop EM inversion program can be applied for the reconnaissance site survey.

• Journal of the Korean earth science society
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• v.27 no.4
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• pp.425-432
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• 2006

A seismic tomography using refraction waves is applied to provide information on depth of basement rocks and leachate distribution of the Noeun waste landfill site for the stage of preliminary environmental survey. This method is generally applied to civil and environmental areas. Three lines, apparently perpendicular to the potential leachate flow direction in this site, were installed to investigate the waste landfill site in pseudo three dimensional geometry. The results show that the site is composed of 3 layers and depth of basement becomes shallower at the upstream area of the landfill site than that of the downstream area. Moreover, some parts of the second layer and the basement at the down stream area are partially infiltrated by the leachate, probably related to the disturbed distribution of the different velocity materials within the second layer. In Conclusion, refraction wave tomography is found to be one of the most efficient way to investigate waste landfill site.

• Geophysics and Geophysical Exploration
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• v.4 no.4
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• pp.124-132
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• 2001

Electrical resistivity survey has been conducted for delineating geological fault structure in Kaekok-ri near Kyungju. In general, electrical resistivity survey has an advantage of searching buried faults and its traces compared with other geophysical survey methods. Distribution of electrical conductivity in the ground is influenced by the ratio of pores, groundwater and clay minerals. These properties are evidenced indirectly to explain for weathering condition, faults and fracture Bones. Thus the electrical resistivity survey can be an effective method to find buried faults. We have carried out two dimensional (2-D) interpretation by means of smoothness-constrained least-squares and finite element method. Field data used in this paper was acquired at Kaekok-ri, Wuedong-eup, Kyungju-si, where is Ulsan Fault and is close to the region in which debatable quaternary fault traces were found recently. The dipole-dipole array resistivity survey which could show the 2-D subsurface electrical resistivity structure, was carried out in the area with three lines. The results showed good property of fault, fracture zone and fault traces which we estimated were congruous with the results. Through this study, 2-D electrical resistivity survey interpretation for fault is useful to apply.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.4 s.11
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• pp.145-151
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• 2003

The domestic and the industry wastes which mainly come out of human life activities have been usually processed mainly by the incineration method and/or the method of reclamation. The method of reclamation, specially open dumping, has caused significant environmental pollution problems on the local or regional soil and groundwater system by leachate. Therefore, to investigate the 3-D structure characteristics of environmental pollution area is one of the hot subjects. We applied dipole-dipole method of electrical resistivity survey to investigate 3-D environmental contamination characteristics of the Noeun landfill area. For electrical resistivity survey, the line for measurements was established parallel to the main boundary of the Noeun landfill, for effective investigation of the whole landfill area. The result shows that the uppermost layer of the Noeun landfill is believed to be stabilized completely, based on the result of electrical resistivity values. However, the lowest layer of the Noeun landfill was partially polluted by leachate. Therefore, the electrical resistivity survey method is believed to be the one of the most effective methods to investigate three-dimensional distribution of leachate occurred in the lower part of landfill area.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.60-67
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• 2008

In this paper we consider an application of the method of electromagnetic (EM) migration to the interpretation of a typical marine controlled-source (MCSEM) survey consisting of a set of sea-bottom receivers and a moving electrical bipole transmitter. Three-dimensional interpretation of MCSEM data is a very challenging problem because of the enormous number of computations required in the case of the multi-transmitter and multi-receiver data acquisition systems used in these surveys. At the same time, we demonstrate that the MCSEM surveys with their dense system of transmitters and receivers are extremely well suited for application of the migration method. In order to speed up the computation of the migration field, we apply a fast form of integral equation (IE) solution based on the multigrid quasi-linear (MGQL) approximation which we have developed. The principles of migration imaging formulated in this paper are tested on a typical model of a sea-bottom petroleum reservoir.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.8
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• pp.1178-1187
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• 2006

The purpose of this study is to conduct a questionnaire survey on the actual conditions of the working uniform and protective equipment put on by street cleaners, then to identify their inconvenience and problems and to draw solutions to improve them, and finally to design a spring-and-autumn street cleaner uniform which has enhanced functionalities such as motional flexibility, safety and soil proof. The questionnaire survey of this study was done by street cleaners who were in charge of street cleaning and collecting the recyclable waste. The result of this study, easily worn-out parts of the working clothing were the sleeve hems and the front part on the upper uniform, and the trouser hems and zipper on the lower uniform. Easily soiled parts were the sleeve hems, parts of arm on the upper uniform, and the trouser hems and knee parts on the lower uniform. Based on the results of the questionnaire survey, the sample uniforms were designed in consideration of material, design and pattern. A soil-proof material was used for easily soiled parts such as sleeve hems, knee parts and trouser hems. Reflective material was applied to the parts such as chest, back and the side lines of sleeves and trousers to raise visibility in working and to ensure safety. A crease was given to each side of the back. The height of sleeve cap was lowered to lift the motional flexibility of back and arm parts. Darts were applied to elbow and knee parts for a three-dimensional design. Gussets were inserted in the thigh part to give it activity. Then quantitative evaluation and a sensory evaluation, which was composed of outward appearance, motional flexibility and fitness for field operation, were conducted. According to these evaluations, the sample uniform was found to be more satisfactory than current uniform.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.8 no.2
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• pp.23-29
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• 1990

Non-metric camera is more profitable than metric camera for geometric analysis of small and elaborate structures, because focal length control of non-metric camera is flexible while generally metric camera has limited focal length. And if the problem of conventional method requiring much time and endeavor to measure three dimensional positions of control points will be solved effectively, it is possible to analyze very close-range photogrammetry more easily and quickly. The purposes of this study are to propose the efficiency of non-metric camera and to reduce difficulty of control survey sharply by introducing self-control survey method. For these, very close-range photographs of the small object were obtained by using non-metric camera calibrated for systematic errors and then bundle adjustment is used for analysis procedure. As a result, the superiority of non-metric camera in analyzing very close-range photographs and the application proptriety of self-control survey were proved, therefore it is expected to be able to apply to precise analysis of small structures or spearhead parts.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.4
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• pp.521-530
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• 2021

Objectives: This was to examine and explore the elements of Size Korea 6th 3D head anthropometric database and to provide basic information for the selection of respirators in Korea. Methods: This was a pilot study for the first year of work in a two-year-project initiated at KOSHA in 2021. 3D head dimensions data were obtained from the Size Korea Center managing the Size Korea 6th 3D national anthropometry survey databases. The 3D head dimensions data, including 45 dimensions, were used in line with ISO standards (e.g., ISO/TS 16976-2) for examinations, comparisons, statistical analyses, etc. Results: A total of 3,088 subjects were finally determined in this study. The main features were: Male subjects were 52.5%; the highest age group was 15-29 at 36.7%; unhealthy weight group based on BMI was 31.7%; and survey area was the capital region. For the 6th 3D head dimensions data with 45 items, the means and standard deviations for 'Face length' were 115.9±7.5 cm for males and 107.3±6.9 cm for females respectively while those for 'Face width' item were not available since there was no such item in the data. Numerous findings were discussed accordingly. Conclusions: This study showed that there were likely requirements for improvements in the 6th 3D head anthropometric data as follows: Standardization of Korean and English terms; addition of head dimensions items missed in the Size Korea survey; and reliability of generalizability for subjects, suggesting that the study results can be used for further studies or improvement of respirator selection in Korea.