• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.83.1-83.1
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• 2012

We have developed an self-consistent PDR model to synthesize warm CO lines of Herschel/PACS observations more accurately. The PDR model solves the FUV continuum radiative transfer, gas energetics, and chemistry simultaneously. A local FUV radiation flux is calculated by using a Monte Carlo method taking anisotropic scattering into account. A new (r, ${\delta}$) coordinate system was used, where the r is the distance from the origin and the ${\delta}$ is z/$R^2$ in the cylindrical coordinate of (R,z). This is an adequate coordinate system to represent a power-law density of an envelope and a high spatial resolution near the outflow wall. The gas enegetics and chemistry are solved locally and considered $10^4K$ blackbody radiation field instead of the interstellar radiation filed. This newly developed model can be used to analyze quantitatively the effect of UV-heated outflow walls on the warm molecular lines in the embedded proto-stellar objects.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.305-311
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• 2005

This research presents a three-dimensional modeling technique for a flexible sheet. A relative coordinate formulation is used to represent the kinematics of the sheet. The three-dimensional flexible sheet is modeled by multi-rigid bodies interconnected by out-of-plane joints and plate force elements. A parent node is designated as a master body and is connected to the ground by a floating joint to cover the rigid motion of the flexible sheet in space. Since the in-plane deformation of a sheet such as a paper and a film is relatively small, compared to out-of-plane deformation, only the out-of-plane deformation is accounted for in this research. The recursive formulation has been adopted to solve the equations of motion efficiently. An example is presented to show the validity of the proposed method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.573-576
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• 2005

This research presents a three-dimensional modeling technique for a flexible sheet. A relative coordinate formulation is used to represent the kinematics of the sheet. The three-dimensional flexible sheet is modeled by multi-rigid bodies interconnected by out-of-plane joints and plate force elements. A parent node is designated as a master body and is connected to the ground by a floating joint to cover the rigid motion of the flexible sheet in space. Since the in-plane deformation of a sheet such as a paper and a film is relatively small, compared to out-of-plane deformation, only the out-of-plane deformation is accounted for in this research. The recursive formulation has been adopted to solve the equations of motion efficiently. An example is presented to show the validity of the proposed method.

• Journal of Korea Multimedia Society
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• v.24 no.11
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• pp.1518-1525
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• 2021

Due to the growth of VR industry and rise of digital twin industry, the importance of implementing 3D data same as real space is increasing. However, the fact that it requires expertise personnel and huge amount of time is a problem. In this paper, we propose a system that generates point cloud data with same shape and color as a real space, just by scanning the space. The proposed system integrates 3D geometric information from lidar and color information from stereo camera into one point cloud. Since the number of 3D points generated by lidar is not enough to express a real space with good quality, some of the pixels of 2D image generated by camera are mapped to the correct 3D coordinate to increase the number of points. Additionally, to minimize the capacity, overlapping points are filtered out so that only one point exists in the same 3D coordinates. Finally, 6DoF pose information generated from lidar point cloud is replaced with the one generated from camera image to position the points to a more accurate place. Experimental results show that the proposed system easily and quickly generates point clouds very similar to the scanned space.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.1
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• pp.170-176
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• 1998

In this paper, the column space and null space of the Jacobian matrix were obtained by using the pseudo-inverse method and projection matrix. The equations of motion of the system were replaced by independent acceleration components using the null space matrix. The proposed method has the following advantages. (1) It is simple to derive the null space. (2) The efficiency is improved by getting rid of constrained force terms. (3) Neither null space updating nor coordinate partitioning method is required. The suggested algorithm is applied to a three-dimensional vehicle model to show the efficiency.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.6
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• pp.330-335
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• 1999

This paper proposed the p-q-r coordinate system where the instantaneous active power p, and the two instantaneous reactive powers qq, qr were defined. The three power components are linearly independent, so the compensation for the two instantaneous reactive powers leads to control the two components of the current space vector. With the theory, the neutral current of a three-phase four-wire system can be eliminated by only compensating the instantaneous reactive power using no energy storge element.

• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.315-320
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• 2013

Space geodetic techniques can be used to obtain precise shape and rotation information of the Earth. To achieve this, the representative combination solution of each space geodetic technique has to be produced, and then those solutions need to be combined. In this study, the representative combination solution of very long baseline interferometry (VLBI), which is one of the space geodetic techniques, was produced, and the variations in the position coordinate of each station during 7 years were analyzed. Products from five analysis centers of the International VLBI Service for Geodesy and Astrometry (IVS) were used as the input data, and Bernese 5.0, which is the global navigation satellite system (GNSS) data processing software, was used. The analysis of the coordinate time series for the 43 VLBI stations indicated that the latitude component error was about 15.6 mm, the longitude component error was about 37.7 mm, and the height component error was about 30.9 mm, with respect to the reference frame, International Terrestrial Reference Frame 2008 (ITRF2008). The velocity vector of the 42 stations excluding the YEBES station showed a magnitude difference of 7.3 mm/yr (30.2%) and a direction difference of $13.8^{\circ}$ (3.8%), with respect to ITRF2008. Among these, the 10 stations in Europe showed a magnitude difference of 7.8 mm/yr (30.3%) and a direction difference of $3.7^{\circ}$ (1.0%), while the 14 stations in North America showed a magnitude difference of 2.7 mm/yr (15.8%) and a direction difference of $10.3^{\circ}$ (2.9%).

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.296-299
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• 2004

KARI precision attitude determination system has been developed for high accurate geo-coding of KOMPSAT-2 image. Sensor data from two star trackers and a IRU are used as measurement and dynamic data. Sensor data from star tracker are composed of QUEST and unit vector filter. Filter algorithms consists of extended Kalman filter, unscented Kalman filter, and least square batch filter. The type of sensor data and filter algorithm can be chosen by user options. Estimated parameters are Euler angle from 12000 frame to optical bench frame, gyro drift rate bias, gyro scale factor, misalignment angle of star tracker coordinate frame with respect to optical bench frame, and misalignment angle of gyro coordinate frame with respect to optical bench frame. In particular, ground control point data can be applied for estimating misalignment angle of star tracker coordinate frame. Through the simulation, KPADS is able to satisfy the KOMPSAT-2 mission requirement in which geo-location accuracy of image is 80 m (CE90) without ground control point.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2157-2163
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• 2011

In this paper, we designed 2D, 2.5D cloth design system and a 3D cloth animation system. They make the 3D cloth animation possible by using coordinate points extracted from 2D and 2.5D cloth design system in order to realize a system that allows customers to wear clothes in the virtual space. To make natural draping, it uses for description the mesh creation and transformation algorithms, path extraction algorithm, warp algorithm, and brightness extraction and application algorithms. The coordinate points extracted here are received as text format data and inputted as clothing information in the cloth file. Moreover, the cloth file has a 2D pattern and is realized to be used in the 3D cloth animation system. The 3D cloth animation system generated in this way builds a web-based fashion mall using ISB (Internet Space Builder) and lets customers view the clothing animation on the web by adding the animation process to the simulation result.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.2
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• pp.57-64
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• 2004

Nowadays the parks in Shanghai tend to develop towards two directions. Small and medimn parks are being gradually transformed from closed management to open management, while large ones emphasize their nature of theme and nature of functions. Simultaneously, the number of large and open public green spaces has been significantly increased. Although the public green space does not adopt the management pattern for parks, there is almost no difference between public green space and ordinary parks so far as the functions and scales are concerned. Due to the fact that there is no obvious boundary between a public park and a public green space, this paper raises a suggestion to coordinate continuously their management and functions so that the distribution of and the connection between the urban green spaces can be more rational and more definite and a sound green network can be formed. Starting from the viewpoint of emphasizing accessibility to green spaces and enhancing the angle of linking green spaces, we aim at transforming a park system to a multifunctional green system, extending the effects and service radius of large green spaces, and strengthening the internal connections with the surrounding areas so that a high-quality green space can be formed with the connection of the green space network.