• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.551-556
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• 2009

3-D CAD (Computer Aided Design) system is an indispensable tool for manufacturing. A lot of engineers have studied for the methods to generate a curved surface on an N-sided shape, which is the basic technology of 3-D CAD systems. This surface generation, however, has three problems on the case of long and narrow shapes: the resultant surface is distorted, the surface is not continuous to adjacent surfaces, or additional user inputs are required to generate the surface. Conventional methods have not yet solved these problems at the same time. In this paper, we propose the method to generate internal curves that divide a long and narrow shape into regular N-sided sections so as to divide the shape into an N-sided section and four-sided ones. Our method controls the shape of internal curves by dividing an N-sided long and narrow shape into an N-sided section and four-sided ones, and solves distortion of the generated curved surface. In addition, each of the generated sections is interpolated with G1-continuous surfaces. This process does not require any user's further input. Therefore, the three problems mentioned above will be solved at the same time.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.35-40
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• 1999

In order to know the characteristics of attenuation of coda wave in the Kyungsang Sedimentary Basin quality factor for coda wave or coda Q is estimated from the earthquake data recorded in the KIGAM microearthquake network. The single scattering model for coda wave generation is adopted in estimating coda Q. Coda Q appears to be largely dependent on the normalized time(a) which is the ratio of elapsed time to S-wave travel time. In the present study coda Q(Qc) is estimated in the range of a=1.5-3.Q and expressed in terms of frequency(f). The deduced function in the range of 1 to 25 Hz is Qc=36.8283 f1.15095 to represent the strong dependence of coda Q on frequency. It is found that the difference of Qc between U-D N-S and E-W components is negligible, This face supports the back-scattering theory that coda were originates from scattered waves by randomly distributed heterogeneities in the crust. On the other hand it is observed that the coda Q increases with depth.

• Fashion & Textile Research Journal
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• v.18 no.6
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• pp.766-775
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• 2016

In the era of globalization and unlimited competition, Korean universities need a breakthrough in their education system according to the changing education landscape, such as lower graduation requirements to cultivate more multi-talented convergence leaders. While each student has different learning capabilities, which results in different performance and achievements in the same class, the uniform education that most universities are currently offering fails to accommodate such differences. Blended learning, synergically combining offline and online classes, enlarges learning space and enriches learning experiences through diversified tools and materials, including multimedia. Recently, universities are increasingly adopting video contents and on-offline convergence learning strategy. Thus, this study suggests a teaching method based on blended learning to more effectively teach existing pattern CAD and virtual CAD in the Apparel Pattern CAD class. To this end, this researcher developed a teaching-learning method and curriculum according to the blended learning phase and video-based contents. The curriculum consisted of 2D CAD (SuperAlpha: Plus) and 3D CAD (CLO) software learning for 15 weeks. Then, it was loaded to the Learning Management System (LMS) and operated for 15 weeks both online and offline. The performance analysis of LMS usage found that class materials, among online postings, were viewed the most. The discussion menu most accurately depicted students' participation, and students who did not participate in discussions were estimated to check postings less than participating students. A survey on the blended learning found that students prefer digital or more digitized classes, while preferring face to face for Q&As.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.3-10
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• 2005

In this study, 1-g shaking table tests on the model of CFR(Concrete-Face Rockfill) type "D" dam in operation and the model of virtual ECRD(Earth Core Rockfill Dam) of which static stability is about the same compared to the model of CFRD were carried out. The purpose of this study is to compare the seismic performance of CFRD and ECRD from the analysis of model test results. Displacement response behavior of the dam was examined through the measurement of vertical and horizontal displacement of model dam crest. Also, amplification characteristics of accelerometers installed with dam height were examined through the measurement of acceleration with dam height. Also, in the case of ECRD, patterns of excess pore pressure generation with dam height were examined. From the test results, it was found that accelerations of dam crest of CFRD and ECRD were amplified about 1.52 times and 2 times compared to the accelerations of dam bottom, respectively. amplification was outstanding at three quarters of dam height from the bottom of dam. This phenomenon was outstanding in case of ECRD. And it was estimated that vertical and horizontal displacement of prototype dam of CFRD were 6.8cm (0.1% of dam height) and 12.3cm (0.2% of dam height), respectively. Also, it was estimated that vertical and horizontal displacement of prototype dam of ECRD were 4.3cm (0.1% of dam height) and 5.5cm (0.11% of dam height), respectively.

• International journal of advanced smart convergence
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• v.13 no.2
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• pp.130-135
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• 2024

The Stable diffsuion AI tool is popular among designers because of its flexible and powerful image generation capabilities. However, due to the diversity of its AI models, it needs to spend a lot of time testing different AI models in the face of different design plans, so choosing a suitable general AI model has become a big problem at present. In this paper, by comparing the AI images generated by two different Stable diffsuion models, the advantages and disadvantages of each model are analyzed from the aspects of the matching degree of the AI image and the prompt, the color composition and light composition of the image, and the general AI model that the generated AI image has an aesthetic sense is analyzed, and the designer does not need to take cumbersome steps. A satisfactory AI image can be obtained. The results show that Playground V2.5 model can be used as a general AI model, which has both aesthetic and design sense in various style design requirements. As a result, content designers can focus more on creative content development, and expect more groundbreaking technologies to merge generative AI with content design.

• Journal of the Korea Society for Simulation
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• v.32 no.3
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• pp.1-8
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• 2023

Modeling of artificial targets in Synthetic Aperture radar (SAR) mainly simulates radar signals reflected from the faces and edges of the 3D Computer Aided Design (CAD) model with a ray-tracing method, and modeling of the clutter on the Earth's surface uses a method of distinguishing types with similar distribution characteristics through statistical analysis of the SAR image itself. In this paper, man-made targets on the surface and background clutter on the terrain are integrated and made into a three-dimensional (3D) point cloud scatterer model, and SAR image were created through computational signal processing. The results of the SAR Stripmap image generation of the actual automobile based SAR radar system and the results analyzed using EM modeling or statistical distribution models are compared with this 3D point cloud scatterer model. The modeling target is selected as an bridge because it has the characteristic of having both water surface and ground terrain around the bridge and is also a target of great interest in both military and civilian use.

• The KIPS Transactions:PartB
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• v.13B no.2 s.105
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• pp.187-196
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• 2006

In 3D animation most people adjust the moving motion of their characters on various terrains by using motion data acquired with the motion capture equipment. The motion data can be used to present real human motions naturally, but the data must be captured again to apply to the different terrains from those given at acquiring mode. In addition, there would be a difficulty when applying the data to other characters, in that case the motion data must be captured newly or the existing motion data must be heavily edited manually. In this paper we propose a unified method to generate human motions of walking and running for various terrains such as flat plane, inclined plane, stairway and irregular face. With these methods we are able to generate human motions controlled by the parameters : body height, moving speed, stride, etc. In the proposed methods, the positions and angles of joint can be calculated by using inverse kinematics, and we calculate the trajectory of the swing leg and pelvis according to the cubic spline. With these methods we were presented moving motions using a model of a human body.

• Journal of KIISE:Software and Applications
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• v.30 no.11
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• pp.1092-1101
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• 2003

Most of 3D character animation adjusts the gait of their characters for various terrains, using motion capture data through the motion capture equipments. This motion capture data can be naturally presented as real human motions, which are to be adjusted according to the various types of terrain. In addition, there would be a difficulty applying motion capture data for other characters in which the motion data will be captured again or edited for the existing motion data. Therefore, this paper proposes a method that is to generate walking motion for various terrains, such as flat, inclined plane, stair, and irregular face, and a method that is to calculate the trajectory of the swing leg and pelvis. These methods are able to generate various gaits controlled by the parameters of body height, walking speed, stride, etc. In addition, the positions and angles of joint can be calculated by using inverse kinematics, and the cubic spline will be used to calculate the trajectory of the joint.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.1
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• pp.74-84
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• 1998

A doubly resonant ultrasonic transducer has been designed as an attempt to increase the bandwidth of underwater transducers. The dual resonance conditions were accomplished by attaching a single acoustic matching layer on the front face of a Tonpilz transducer consisted of an aluminum head, a piezoelectric ring, a brass tail and a prestress bolt. A modified Mason's model was used for the performance analysis and the design of transducers, and the constructed transducers were tested experimentally and numerically by changing the impedances and thicknesses of the head, tail and matching layers in the water tank. Two distinct resonance peaks in the transmitting voltage response(TVR) of a developed transducer were observed at 34.3 and 40.4 kHz, respectively, with the difference frequency of 6.1kHz and the center frequency of 37.2kHz. The values of TVR at these frequencies were 136.5 dB re $1\;\muPa/V$ at 34.3 kHz and 136.8 dB re $1\;\muPa/V$ at 40.4 kHz, respectively. Reasonable agreement between the experimental results and the numerical results was achieved. From this result, it is expected that the generation of the distinct resonances at any two desired frequencies can be achieved through the proper choice of the matching layer to provide the impedance transformation between the transducer and the medium.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.4
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• pp.403-415
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• 2014

Recently, the temperature rise in the summer due to climate change, power usage is increasing rapidly. As a result, power generation facilities have been newly completed and the need for ultra-high-voltage transmission line for power transmission of electricity to the urban area has increased. The mechanized tunnelling method using a shield TBM have an advantage that it can minimize vibrations transmitted to the ground and ground subsidence as compared with the conventional tunnelling method. Despite the popularity of shield TBM for cable tunnel construction, study on the mechanical behavior of cable tunnel driven by shield TBM is insufficient. Thus, in this study, the effect of fractured zone ahead of tunnel face on the mechanical behavior of the shield TBM cable tunnel is investigated. In addition, it is intended to compare the behavior characteristics of the fractured zone with continuous model and applying the interface elements. Tunnelling with shield TBM is simulated using 3D FEM. According to the change of the direction and magnitude of the fractured zone, Sectional forces such as axial force, shear force and bending moment are monitored and vertical displacement at the ground surface is measured. Based on the stability analysis with the results obtained from the numerical analysis, it is possible to predict fractured zone ahead of the shield TBM and ensure the stability of the tunnel structure.