• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.49.2-49.2
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• 2013

We report preliminary results from a radio study of central galaxies in cool and non-cool core clusters. A cooling flow is expected to rapidly form in the center of galaxy clusters unless additional heating mechanisms such as merging with sub clusters are at work. It has been suggested that cool flows can feed the AGN in the central galaxies, increasing their power. On the other hand, the AGN feedback can also affect the surrounding medium, heating back up the gas in the cluster core region. In this study, we investigate the co-evolution of cool flows and the AGN of galaxies located in the cluster center. For this study, we have selected 13 radio bright central galaxies from clusters with a range of cooling time scale. In this work, we present results of our recent observations using the Korean VLBI Network. We discuss the properties of the sample in radio and other wavelengths.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.4
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• pp.767-779
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• 2017

Automated mission planning for unmanned aerial vehicles (UAVs) is difficult because of the propagation of several sources of error into the solution, as for any large scale autonomous system. To ensure reliable system performance, we quantify all sources of error and their propagation through a mission planner for operation of UAVs in an obstacle rich environment we developed in prior work. In this sequel to that work, we show that the mission planner developed before can be made robust to errors arising from the mapping, sensing, actuation, and environmental disturbances through creating systematic buffers around obstacles using the calculations of uncertainty propagation. This robustness makes the mission planner truly autonomous and scalable to many UAVs without human intervention. We illustrate with simulation results for trajectory generation of multiple UAVs in a surveillance problem in an urban environment while optimizing for either maximal flight time or minimal fuel consumption. Our solution methods are suitable for any well-mapped region, and the final collision free paths are obtained through offline sub-optimal solution of an mTSP (multiple traveling salesman problem).

• International Journal of Aeronautical and Space Sciences
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• v.15 no.3
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• pp.320-334
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• 2014

Over the last two decades, numerous experimental and numerical efforts have examined physical phenomena in plasma discharge devices. The physical mechanisms that govern the anomalous electron diffusion from the cathode to the anode in the Hall Effect Thruster (HET) are not fully understood. This work used 1-D numerical method to improve our understanding and gain insight into the effect of the anomalous electron diffusion in the HET. To this end, numerical solutions are compared with various experimental HET performance measurements and the effects of anomalous electron diffusion are analyzed. The relationships between the anomalous electron diffusion and important parameters of the HET are also studied quantitatively. The work identifies the cathode mass flow rate fraction, radial magnetic field distribution, and discharge voltage as significant factors that affect anomalous electron diffusion. Additionally, the study demonstrates a computational process to determine the radial magnetic field distribution required to achieve specific thruster performance goals.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.1
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• pp.36-43
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• 2015

Optimizing multiple design characteristics which are usually in conflict with each other in the injection molding process is frequently becoming a critical problem for designers who work in this area. The purpose of this work is to develop an automated design methodology for optimizing two such design characteristics found in injection-molded parts. A value function based on decision-making theory is used as a means of evaluating the performance of a two-characteristic design alternative. Also, a design space reduction algorithm based on Taguchi's orthogonal arrays is utilized to discover an optimal design alternative. Verification of the developed design methodology is carried out for an actual model with two design characteristics, the weld line and the gate location, to be optimized in computer simulation experiments.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.298-301
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• 2006

The HIBRAND located in Yangjaedong, Seochogu, Seoul is a large complex shopping center of total space 48,000 p'yongs which consists of a nineteen-story business facility and a six-story sale facility. In the case of a big construction work in the downtown, they are suffered much difficulty by construction period and working space lack. They, however, can satisfy construction period, constructability and quality using a PC system in HIBRAND. Also, we maximized the advantage of each material being the abreast of a RC and steel structure method partially and devised a reasonable copula. A PC system with advantages of construction period, constructability and quality assurance should be actively practiced to big downtown construction work.

• Journal of The Korea Institute of Healthcare Architecture
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• v.13 no.1
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• pp.7-15
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• 2007

The medicine is used for diagnosis, treatment or prevention of disease and consequently has an important influence upon human life and health. Its effectiveness and safety must be guaranteed. In order to achieve the facility that meets GMP, KFDA has provided standards for quality assurance of the manufacture, examination and tests of medical supplies. The result of this study were as follows : the GMP facilities are divided into work, lab/test and storage spaces, and the systematic corridor. The clean rooms are mainly installed in work and lab/test spaces, and maintain class 10,000 in average. The individual space for the procedures that requires class 100 is not provided as a separate division. Instead, they are performed in the clean bench of the laboratory.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.363-368
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• 1995

A general method of solving inverse kinematics of three-joint manipulator composed of revolute joints or prismatic joints or combinations of those joints is presented in this study. In completing real-time control, it is very important to obtain the closed form solutions of inverse kinematics rather than iterative numerical solutions, because iterative numerical solutions are generally much slower than the corresponding closed form solutions. If it is possible to obtain the inverse kinematic solutions for general cases of considering twist anlges and offsets, the manipulator work space can be designed and enlarged more effciently for specific task. Moreover, in idustrial manipulators, the effect of main three joints is larger than that of the other three joints related to orientation in the view of work space. Therfore the solutions of manin three-joint are considered. Even The inverse kinematic equations are complicatedly coupled, the systematical solving process by using symbolic calculation is presented.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.419-422
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• 2010

In this study, I executed civil engineering design and compared it with the existing method in order to analyze the expected effect of civil engineering design by using three dimensional space information and its advantages. Through a series of processes, it is possible to enhance the usability of three-dimensional space information, expected more accurate calculation of earth work and proceed with more reasonable construction in soil conversion and civil engineering work. Also, it enables improvement of productivity by establishing efficient construction plan.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.10a
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• pp.17-24
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• 1995

This work proposes an optimality criteria applicable to the optimum design of plane frames. Stress constraints as well as displacement constraints are treated as behavioural constraints and thus the first order approximation of stress constraints is adopted. The design space of practical reinforced concrete frames with discrete design variables has been found to have many local minima, and thus it is desirable to find in advance the mathematical minimum, hopefully global, prior to starting to search a practical optimum design. By using the mathematical minimum as a trial design of any search algorithm, we may not full into a local minimum but apparently costly design. Therefore this work aims at establishing a mathematically rigorous method ⑴ by adopting first-order approximation of constraints, ⑵ by reducing the design space whenever minimum size restrictions become "active" and ⑶ by the of Newton-Raphson Method.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2004.11a
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• pp.112-115
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• 2004

Avante-garde arts which are still being continued until now has become not only just a forefather of art, but also the tradition of modern arts which are still being held on. Rem Koolhaas is growing his reputation as an architect like Le Corbuster. Space image and related documents analysis and characteristic interior image analysis rather than whole concept or the structure analysis, which first, making a analysis tool from derived characteristics from theoretical guidance of avante-garde and then by deriving characteristics of avante-garde arts from space consists of Rem Koolhaas, was able to identify that in his work consists contained characteristics of avante-garde arts