• Journal of the Society of Naval Architects of Korea
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• v.49 no.1
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• pp.26-32
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• 2012

The 3-D unsteady viscous flow around an impulsively started rotating marine propeller is simulated using VIC(Vortex-In-Cell) method which is adequate to analyze the strong vortical flow around complicatedly-shaped body. The computational procedure is governed by the vorticity transport equation in Lagrangian form. In order to solve the equation, a regular grid which is independent to the shape of a body is introduced and each term of the equation is evaluated numerically on the grid by applying immersed boundary concept. In this paper, the overall algorithm including the formulation of governing equations and boundary conditions is described and some computational results are presented with discussing their physical validity.

• Geomechanics and Engineering
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• v.25 no.3
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• pp.233-243
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• 2021

Rib spalling is a major issue affecting the safety of steeply inclined coal seam. And the failure coal face and support system can be affected with each other to generate a vicious cycle along with inducing large-scale collapse of surrounding rock in steeply inclined coal seam. In order to analyze failure mechanism and propose the corresponding prominent control measures of steeply inclined coal working face, mechanical model based on coal face-support-roof system and mechanical model of coal face failure was established to reveal the disaster mechanism of rib spalling and the sensitive analysis of related factors was performed. Furthermore, taking 3402 working face of Chen-man-zhuang coal mine as engineering background, numerical model by using FLAC3D was built to illustrate the propagation of displacement and stress fields in steeply inclined coal seam and verify the theory analysis as mentioned in this study. The results show that the coal face slide body in steeply inclined working face can be observed as the failure height of upper layer smaller than that of lower layer exhibiting with an irregular quadrilateral pyramid shape. Moreover, the cracks were originated from the upper layer of sliding body and gradually developed to the lower layer causing the final rib spalling. The influence factors on the stability of coal face can be ranked as overlying strata pressure (P) > mechanical parameters of coal body (e.g., cohesion (c), internal fraction angle (φ)) > support strength (F) > the support force of protecting piece (F') > the false angle of working face (Θ). Moreover, the corresponding control measures to maintain the stability of the coal face in the steeply inclined working face were proposed.

• Fashion & Textile Research Journal
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• v.9 no.6
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• pp.581-588
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• 2007

The purposes of this study are to look into the formative characteristics of the miniskirt and to evaluate the visual effects and images according to changes in the silhouette and length of the miniskirt from analyzing the mini skirt style shown in 2007 S/S domestic fashion. The miniskirt style shown in 2007 S/S domestic fashion was analyzed with pictures from a fashion website "Interfashion Planning" from Feb. to May of 2007. As a result, the basic lines of the miniskirt are classified into two types according to the side line. The lengths of miniskirts are classified into five steps of 25 cm, 27.5 cm, 30 cm, 32.5 cm, and 35 cm from the natural waistline. The stimuli were produced with imaginative sewing system 3D CAD of i-design series. For the visual evaluation according to changes in the silhouettes and length of the miniskirt, we used 13 pairs of items to find the visual effects, and 23 pairs of adjectives to measure the visual images. The stimuli and adjectives were randomly given to the evaluators and were evaluated by the 7-point likert type scale. Data we got from this experiment was analyzed statistically by using the SPSS 12.0 and practiced the Factor Analysis and Correlation Analysis. Formative characteristics of miniskirts can be found in the lines, colors, and materials that are the elements of fashion designs, colors and materials are the characteristics of the cloth that is the medium of the expression of designs. The result of factor analysis of visual effects and visual images according to changes in the silhouettes and lengths of miniskirts, the visual effect was composed of the three factors of the length of the lower body, the thickness of the lower body, and the shape abdomen and it was showed that these three factors occupied 63.6% of the total variance. The visual image was composed of four factors of elegance, personality, attraction, maturity and these four factors got 67.6% of the total variance.

• Journal of electromagnetic engineering and science
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• v.16 no.2
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• pp.87-99
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• 2016

This paper describes an implementation method and the results of numerical mobile phone models representing real phone models that have been released on the Korean market since 2002. The aim is to estimate the electromagnetic absorption in the human brain for case-control studies to investigate health risks related to mobile phone use. Specific absorption rate (SAR) compliance test reports about commercial phone models were collected and classified in terms of elements such as the external body shape, the antenna, and the frequency band. The design criteria of a numerical phone model representing each type of phone group are as follows. The outer dimensions of the phone body are equal to the average dimensions of all commercial models with the same shape. The distance and direction of the maximum SAR from the earpiece and the area above -3 dB of the maximum SAR are fitted to achieve the average obtained by measuring the SAR distributions of the corresponding commercial models in a flat phantom. Spatial peak 1-g SAR values in the cheek and tilt positions against the specific anthropomorphic mannequin phantom agree with average data on all of the same type of commercial models. Second criterion was applied to only a few types of models because not many commercial models were available. The results show that, with the exception of one model, the implemented numerical phone models meet criteria within 30%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1577-1583
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• 2012

Penetrator with enhanced lateral effect (PELE) is a novel projectile that does not require dynamite and a fuse. It comprises a high-density jacket that is closed at its rear end and filled with a low-density filling material. To study the explosion characteristics of PELE using AUTODYN-3D code, the calculation models of the projectile body and the bullet target were developed and the process of penetrating an aluminum-2024 alloy target using PELE was simulated. The scattering characteristics after PELE penetrated the aluminum-2024 alloy target were studied for different filling materials. The explicit finite element analysis of PELE fragmentation was implemented with the stochastic failure criterion in AUTODYN-3D code. As the filling expanded, the fragments gained velocity and dispersed laterally, increasing the damage area considerably. The number and shape of PELE fragments differed depending on the impact pressure of the filling that fragmented during the penetration and lateral dispersion processes.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.2
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• pp.497-501
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• 2008

3D facial scanner for an accurate analysis is measured precisely a distance in straight, a distance in curved line, an angle in 3D data, the area of surface. We can easy acquire 3D data by the method of 0.8sec in each scan with easy handling, simple merge to whole face, harmless and fast process. In the HyungSang medicine, the inspection of the facial shape includes the Dam(gall bladder) - Bang Kwang(urinary bladder) body, the Jung${\cdot}$Gi${\cdot}$Shin${\cdot}$Hyul, the six merdian types etc. And we will collect the evidence based date verifing in the HyungSang clinical medicine. As we will analyze the facial whole form and the size${\cdot}$length${\cdot}$angle of the facial part, put the facial form's standardization on a solid foundation.

• Conservation Science in Museum
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• v.25
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• pp.1-8
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• 2021

This study investigated White Porcelain Water Dropper with Openwork Lotus Scroll Design and Eight Trigram Design in Cobalt-blue Underglaze (hereinafter, the "water dropper") in the collection of the National Museum of Korea using computed tomography (CT). A replica was produced to examine both the structure and its original production method. The CT scanning identified no joint lines or pores in the clay, which suggests that the body (the lower part of the water dropper) was shaped in a single piece using a mold and was then matched with a mold-formed lid (the upper part of the water dropper). The inner container of the body portion was roughly trimmed with a bamboo knife so that its upper surface could be securely attached to the bottom of the lid and prevent any leakage in the joined surface. It appears that the inner container for storing water was made first in a cylindrical shape that met the unit of quantity used at the time and could be easily formed by molding. It was transformed into a trapezoid shape during the process of combining it with the lid. A cylindrical inner container was reproduced using silicon 3D printing to compare its capacity with that of the original inner container. The comparison revealed that the reproduced container had a capacity of 152.5㎖, whereas the original container holds approximately 168.6㎖, a figure similar to three hop (around 174㎖) in Joseon-period units of quantity. Since the capacity of the cylindrical inner container corresponds to a known measure from the late Joseon dynasty, it is likely that the water dropper was originally produced to contain a cylindrical inner container.

• Fashion & Textile Research Journal
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• v.16 no.6
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• pp.1001-1007
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• 2014

We surveyed the wearing characteristics of hip protectors. The problems of existing hip protectors were identified and the directions for improvement were presented. The evaluation of wearing characteristics was conducted on the 100 elderly women (60 to 85 years) with 5 types of hip protector. The questionnaire was composed of history and characteristics on falling, hip protector acceptance, preference, use characteristics and improvement requirements. The result of wearing characteristic evaluation indicated that 52% of the subject experienced falling in winter. Incidents resulting from falling occurred: outdoors (74.5%), bathroom (10.9%), and kitchen (5.5%). Body parts to be protected were in several areas: 35.6% for lumbar, 26.9% for hip joint, and 15% for hip bone. Participants prefer a belt B type design at a rate of 56.9% because it provided a sense of stability by clinging to the body and upholding the waist. Belt B type was the most appropriate in terms of fit, allowance, mobility, and design except pad thickness. To reduce the risk of hip fracture, hip protector needs to be designed in consideration of user's type of fall and body shape. The pattern and size of a hip protector has to be improved in regards to the amount of discomfort. An objective evaluation is needed for the ergonomic design of a hip protector based on and analysis of 3D body image of the elderly and the shock-absorbing quality of pad.

• The Korean Journal of Mycology
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• v.12 no.4
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• pp.164-169
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• 1984

Interspecific heterokaryons were obtained between auxotrophic mutants of Pleurotus ostreatus and Pleurotus florida by polyethylene $glycol-Ca^{++}$ induced fusion of somatic protoplasts. The fusion products produced colonies of dense growing mycelium after 10-14 days culture on hypertonic Mushroom Minimal Medium. When they were transferred to Mushroom Minimal Medium plates, the sectors showed normal vegetative morphology but the colonies of irregular shape varied in growth rate. All of the colonies produced fruit body of normal pilei. Some heterokaryon colonies bearing none or only a small amounts of basidiospores were isolated. Fusion products, generally, gave higher basidiocarp yields than the parents.

• Transactions of Materials Processing
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• v.9 no.4
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• pp.362-371
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• 2000

In order to reduce weight of a high-speed railroad vehicle, the main body has been manufactured by hollow section extrusion using aluminum alloys. A porthole die has utilized for the hollow section extrusion process, which causes complicated die geometry and flow characteristics. Design of porthole die is very difficult due to such a complexity. The three-dimensional finite element analysis for hollow section is also an arduous job from the viewpoint of appropriate mesh construction and tremendous computation time. In the present work, mismatching refinement, an efficient domain decomposition method with different mesh density for each subdomain, is implemented for the analysis of the hollow section extrusion process. In addition, a modified grid-based approach with the surface element layer is utilized lot three-dimensional mesh generation of a complicated shape with hexahedral elements. The effects of porthole design are discussed through the simulation for extrusion of an underframe part of a railroad vehicle. An experiment has also been carried out for the comparison. Comparing the velocity distribution at the outlet with the thickness variation of the extruded part, it is concluded that the analysis results can provide reliable measures whether the die design is acceptable to obtain uniform part thickness. The analysis results are then successfully reflected on the industrial porthole die design.