• Korean Journal of Heritage: History & Science
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• v.35
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• pp.100-118
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• 2002

Originally, Gyeongcheonsa pagoda was located in Busosan, Jungyeon-ri, Gwangdeok-myeon, Gaepung-gun, Gyeonggi-do,but it has suffered from being taken out to Japan illegally in 1907 and being returned to Korea in 1918. After returned to Korea, Gyeoncheonsa Pagoda had been neglected and restored in 1960. It had been exhibited outside the Gyeingbokgung Palace after restoration, but many problems were raised. It was taken to pieces in 1995 and it is conservation and restoring today. However, the top of pagoda is necessary to be researched about its archetype because the shapes of stupa in 1902 and in 1960(the shape of pagoda after restoration) are all different from its archetype. According to picture datum in 1902, the top of pagoda was a Korean building type on a 10 layered roof stone. On the other hand, when it was restored in 1960, cement suspected as a anda was taken place between Korean building type and a 10 layered roof stone. Therefore, I am going to examine Restoration of Gyeongcheonsa pagoda in this thesis. When we examine historical records of Geongcheonsa and datum of parts, we can know that the pagoda was established in 1348(Goryeo Dynasty) but it is difficult to know the truth of its establishment and demolition of Gyeongcheonsa-temple. Three ways to restore the top of the pagoda of Gyeoncheonsa Pagoda can be c o n s i d e r e d . First, Korean building type made by metals is located on a 10 layered roof stone, which is same to picture datum in 1902. Second, the shape of and a type, which is similar to the shape when it was restored in 1960's. Also it is similar to Lamapagoda type. Third, to restore the top of pagoda of gabled roof type, which is similar to the top of pagoda of Wongaksagi P agoda. However it is necessaray to exmamine functions about circle grooves hollowed out in a 10 layered roof stone in restoration. Also we need to find out the archetype of dragon sculpture through the dragon claws left on an edge of a 10 layered roof stone.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.3
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• pp.169-176
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• 2019

In the present study, a CFD/DSMC hybrid method performed by a coupled analysis between the CFD method and the DSMC method was developed to obtain the flow information on the rarefied gas flows effectively. Flow simulations around the high speed vehicles on the transition flow regimes were conducted by using the developed method. The FRESH-FX vehicle made of cone and cylinder shapes was considered for the simulations. The results of the hybrid method were compared with the results of the pure CFD and the pure DSMC method to confirm the reliability and efficiency of the hybrid method. It was found that the gradient and the intensity of the shock waves were weakened due to the relatively low density on the transition flow regime. It was confirmed that the results of the hybrid analysis were different to those of the pure CFD analysis and almost identical to those of the pure DSMC analysis. In addition, the computational time of the hybrid method was reduced than that of the pure DSMC method. As a result, it was obtained that the validity and the efficiency of the CFD/DSMC hybrid method.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.3
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• pp.19-28
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• 2018

Key factors that ensure competitiveness of modular unit include consistent high quality and connection condition that ensures high structural performance while minimizing the overall scale of the on-site process. However, it is difficult to evaluate the structural performance of the connection of modular unit, and its structural analysis and design method can be different depending on the connection to its development, which affects the seismic performance of its final design. In particular, securing the seismic performance is the key to designing modular systems of mid-to-high-rise structure. In this paper, therefore, the seismic performance of the modular system with bracket-typed fully restrained moment connections according to stiffness and the shapes of various connection members was evaluated through experimental and analytical methods. To verify the seismic performance, a cyclic loading test of the connection joint of the proposed modular system was conducted. As a result of this study, theoretical values and experimental results were compared with the initial stiffness, hysteresis behavior and maximum bending moment of the modular system. Also, the connection joint was modeled, using the commercial program ANSYS, which was then followed by finite element analysis of the system. According to the results of the experiment, the maximum resisting force of the proposed connection exceeded the theoretical parameters, which indicated that a rigid joint structural performance could be secured. These results almost satisfied the criteria for connection bending strength of special moment frame listed on KBC2016.

• Journal of the Korea Institute of Building Construction
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• v.20 no.6
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• pp.537-543
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• 2020

The window cleaning works are manpower-dependent and are performed in an unstable posture at high altitude, so that there is a risk of falling. Therefore, there is an urgent need to improve the safety of workers. In this study, a conceptual design was proposed for the cleaning of exterior windows of a building, and the economic feasibility of the proposed conceptual model was analyzed. The proposed model is designed to avoid protrusions such as window frames, and to be able to respond even if the shapes of the upper and lower parts are different. As a result of analyzing the economic feasibility of the designed conceptual model, the benefit cost ratio was 4.48, which was significantly higher than 1. Therefore, the economic feasibility of the proposed window cleaning device is expected to be sufficient. The results analyzed in this paper will be used in the development and marketing of the window cleaning device.

• Journal of Korean Neurosurgical Society
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• v.64 no.4
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• pp.514-523
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• 2021

Objective : Aneurysm volume quantification (AVQ) using the equation of ellipsoid volume is widely used although it is inaccurate. Furthermore, AVQ with 3-dimensional (3D) rendered data has limitations in general use. A novel universal method for AVQ is introduced for any diagnostic modality and application to any shape of aneurysms. Methods : Relevant AVQ studies published from January 1997 to June 2019 were identified to determine common methods of AVQ. The basic idea is to eliminate the normal artery volume from 3D model with the aneurysm. After Digital Imaging and Communications in Medicine (DICOM) data is converted and exported to stereolithography (STL) file format, the 3D STL model is modified to remove the aneurysm and the volume difference between the 3D model with/without the aneurysm is defined as the aneurysm volume. Fifty randomly selected aneurysms from DICOM database were used to validate the different AVQ methods. Results : We reviewed and categorized AVQ methods in 121 studies. Approximately 60% used the ellipsoid method, while 24% used the 3D model. For 50 randomly selected aneurysms, volumes were measured using 3D Slicer, RadiAnt, and ellipsoid method. Using 3D Slicer as the reference, the ratios of mean difference to mean volume obtained by RadiAnt and ellipsoid method were -1.21±7.46% and 4.04±30.54%, respectively. The deviations between RadiAnt and 3D Slicer were small despite of aneurysm shapes, but those of ellipsoid method and 3D Slicer were large. Conclusion : In spite of inaccuracy, ellipsoid method is still mostly used. We propose a novel universal method for AVQ that is valid, low cost, and easy to use.

• Structural Engineering and Mechanics
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• v.77 no.1
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• pp.47-56
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• 2021

This paper deals with damage detection using a Gapped Smoothing Method (GSM) combined with deep learning. Convolutional Neural Network (CNN) is a model of deep learning. CNN has an input layer, an output layer, and a number of hidden layers that consist of convolutional layers. The input layer is a tensor with shape (number of images) × (image width) × (image height) × (image depth). An activation function is applied each time to this tensor passing through a hidden layer and the last layer is the fully connected layer. After the fully connected layer, the output layer, which is the final layer, is predicted by CNN. In this paper, a complete machine learning system is introduced. The training data was taken from a Finite Element (FE) model. The input images are the contour plots of curvature gapped smooth damage index. A free-free beam is used as a case study. In the first step, the FE model of the beam was used to generate data. The collected data were then divided into two parts, i.e. 70% for training and 30% for validation. In the second step, the proposed CNN was trained using training data and then validated using available data. Furthermore, a vibration experiment on steel damaged beam in free-free support condition was carried out in the laboratory to test the method. A total number of 15 accelerometers were set up to measure the mode shapes and calculate the curvature gapped smooth of the damaged beam. Two scenarios were introduced with different severities of the damage. The results showed that the trained CNN was successful in detecting the location as well as the severity of the damage in the experimental damaged beam.

• Steel and Composite Structures
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• v.39 no.1
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• pp.65-80
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• 2021

Irregularities of a building in plan and elevation, which results in the change in stiffness on different floors highly affect the seismic performance and resistance of a structure. This study motivated to investigate the seismic responses of high-rise steel-frame buildings of twelve stories with various stiffness irregularities. The building has five spans of 3200 mm distance in both X- and Z-directions in the plan. The design package SAP2000 was adopted for the design of beams and columns and resulted in the profile IPE500 for the beams of all floors and box sections for columns. The column cross-section dimensions vary concerning the number of the story; one to three: 0.50×0.50×0.05m, four to seven: 0.45×0.45×0.05 m, and eight to twelve: 0.40×0.40×0.05 m. Real recorded ground accelerations obtained from the Vrancea earthquake in Romania together with dead and live loads corresponding to each story were considered for the applied load. The model was validated by comparing the results of the current method and literature considering a three-bay steel moment-resisting frame of eight-story height subject to seismic load. To investigate the seismic performance of the buildings, the time-history analysis was performed using ABAQUS. Deformed shapes corresponding to negative and positive peaks were provided followed by the story drifts and fragility curves which were used to examine the probability of collapse of the building. From the results, it was concluded that regular buildings provided a seismic performance much better than irregular buildings. Furthermore, it was observed that building with torsional irregularity was more vulnerable to seismic failure.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.5
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• pp.10-17
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• 2021

In this study, cold-flow test of simulant gel is conducted using a pressure swirl injector to identify spray characteristics according to gellant weight percent. Experiment results show the aircore is developed locally at the nozzle and expanded to the entire swirl chamber as the supply pressure increases. The aircore formation of simulant gel showed no significant difference compared to Newtonian fluid. The spray pattern was classified into four distinct shapes where relationship between the breakup regimes and dimensionless numbers were investigated. In the future, additional study is necessary to understand the aircore formation mechanism, stability and spray characteristics at different configuration of the swirl chamber shape.

• Textile Coloration and Finishing
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• v.34 no.1
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• pp.38-45
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• 2022

Sound absorbing materials are being developed in various materials and shapes and they are being applied in many fields such as construction, transportation, civil engineering, and sound. Among many sound-absorbing materials, polyester fiber has no environmental problems and harmfulness, and is a material with good sound absorption properties while being inexpensive. So it is manufactured as a nonwoven sound-absorbing material and used in various fields. In this study, polyester dry-laid nonwoven with different basis weight were manufactured using three types of polyester staple fibers: regular solid, single-hole hollow, and low linear density. We focused on the effects of the properties of the fibers, which constitute nonwovens, on the sound absorption properties, and we considered the basis weight. As the basis weight of the nonwoven fabric increased, the pore size became smaller and the air permeability was lowered, but the sound absorption coefficient was higher. However, the single-hole hollow polyester fiber did not contribute to the increase of the sound absorption coefficient of the nonwoven. It was established that, lower fiber fineness caused the sound absorption coefficient of the nonwoven to be increased. It was also found that the increase in the sound absorption coefficient due to the application of low fineness appeared from a certain basis weight or more.

• Journal of the Korea Fashion and Costume Design Association
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• v.24 no.3
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• pp.127-144
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• 2022

This paper aims to analyze the different external images of women expressed in ancient artwork through the socio-cultural background and the aesthetic view during the Tang and Song dynasties of China. The research method contains a literature review involving the collection of historical literature, thesis, and artwork data. The image of women according to the aesthetic view of the two periods is summarized as follows. In terms of face shape, the Tang pursued a round face while the Song pursued a more slender shape. As for hair ornamentation, the Tang wore various shapes of hair buns like "Paojiaji", and decorated them with coronets. The Song wore various types of braided hair called "Tongxinji", but the coronets were smaller and more sophisticated. For makeup, the Tang wore colorful and heavy makeup and the Song makeup was lighter and more elegant. In attire, the Tang followed revealed shape, used splendid colors and thin, transparent material. The Song exhibited a more simple design and was conservative and neat, using luxurious silk fabric with low chroma. In body shape, the Tang pursued the "beauty of obesity" with a voluptuous body shape; the Song pursued the "beauty of gaunt" with a slim body shape. As the result of the analysis according to the aesthetic views of the Tang and Song dynasties, women of Tang were depicted as rich, and women of Song were rather neat. The research on the aesthetic views that changed according to the development of social civilization and the status of women will play an active role in the transmission and development of traditional Chinese culture. At this point, the paper may contribute to the creation of images of women as well as changes in the art of future generations.