• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.69-73
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• 2004

This paper deals with the transient performance of zero signal reference grid(ZSRG) and insulated/isolated ground(IG) in case of lightning strike or surge currents in buildings. Using HIFREQ, which is a commercial code for electromagnetic field analysis, the difference of transient performances of ZSRG and IG type grounding structure have been presented based on the numerical calculations. It is expected that the quantitative and numerical calculation based analysis, which is adopted in this paper, will attribute to the selection of optimal grounding method in the intelligent buildings.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.38-43
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• 1994

To provide more instructive and a safer ground control operation environments for satellite operators, and subsequently to implement a better look-and-feel user interface and a structural mechanism to enhance the efficiency of control and monitoring facilities, we have developed a prototype(laboratory model) ground control softwares targeting for the first generation KOREASAT scheduled to be launched in 1995. As far as the functionality is concerned, the developed system is covering almost all the mission phase operational functions except for some functions like antenna tracking control that are necessary for real operation environments. Most of the functions of the system is realized in softwares but some hardwares needed for TM/TC RF communications are also included in it. The system is now being integrated and under the system test. The performance and functionality is to be evaluated by the end of this year by using the satellite software simulator. Next year, this system could be configured to be used as a workbench for a online/off-line analysis of the operating KOREASAT satellites.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.10
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• pp.26-33
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• 2004

Ultra precision grinding technology has been developed from the refinement of the abrasive, the development of high stiffness equipment and grinding skill. The conventional wafering process which consists of lapping, etching, 1 st, 2nd and 3rd polishing has been changed to the new process which consists of precision surface grinding, final polishing and post cleaning. Especially, the ultra precision grinding of wafer improves the flatness of wafer and the efficiency of production. Furthermore, it has been not only used in bare wafer grinding, but also applied to wafer back grinding and SOI wafer grinding. This paper focuses on the flatness of the ground wafer. Generally, the ground wafer has concave pronto because of the difference of wheel path density, grinding temperature and elastic deformation of the equipment. Wafer tilting is applied to avoid non-uniform material removal. Through the geometric analysis of wafer grinding process, the profile of the ground wafer is predicted by the development of profile simulator.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.9
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• pp.841-848
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• 2016

In this paper, a microstrip-fed dual-band monopole antenna with DGS(: Defected Ground System) for WLAN(: Wireless Local Area Networks) applications was designed, fabricated and measured. The proposed antenna is based on a microstrip-fed structure, and composed of two strip lines and DGS structure and then designed in order to get dual band characteristics. We used the simulator, Ansoft's High Frequency Structure Simulator(: HFSS) and carried out simulation about parameters W2, L10, W3, and DGS to get the optimized parameters. The proposed antenna is made of $21.0{\times}36.0{\times}1.6mm3$ and is fabricated on the permittivity 4.4 FR-4 substrate. The experiment results are shown that the proposed antenna obtained the -10 dB impedance bandwidth 700 MHz(2.10~2.80 GHz) and 1,780 MHz(5.02~6.80 GHz) covering the WLAN bands. Also, the measured gain and radiation patterns characteristics of the proposed antenna are presented at required dual-band(2.4GHz band/5.0GHz band), respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.183-188
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• 2008

Engine control/performance model for helicopter simulator is one of the most important models which affect flight performance and handling quality. It is typical to develop the model based on the raw data and models from the engine designers/manufacturers. The approaches in this study were to develop the basic model based on the available resources and to tune and verify it based on the ground/flight test results. The maintenance manuals of TB3-117 which is installed in KA-32T were reviewed and the components to be simulated for the engine control model were categorized and modeled. Piece-wise linear modeling method was used for the engine performance model. The engine performance data in the engine maintenance manuals were incorporated into the engine steady state performance tables, which were incorporated with the transfer functions for the dynamic performance. Engine control/performance model was compared and tuned with the ground/flight test results. It was verified that the fidelity of the model was within the tolerances in FAA AC120-63.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.891-893
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• 2012

Currently, aircraft and automobile simulator for training provides a variety of training by making hypothetical situation on a simulator Installed on the ground Currently. And the instructor maximizes the effectiveness of the training by Monitoring training and instructing the required training. When trainees are boarding the aircraft or automobile. The Instructor in the ground is not able to monitoring aircraft, automobile. The assessment of the training is not easy after the end of the training Therefore, it is difficult to provide high quality of education to the students. In this paper, Simulation software is to develop the following. Collecting GPS and real-time information for aircraft, automobile ${\grave{a}}implementing$ 3D simulation. Implementing Current image of the aircraft or automobile in the screen by 3D Real-time monitoring of training situation at the control center utilizing for training saving 3D video files Analysis, evaluation on training After the end of the training.

• Journal of Broadcast Engineering
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• v.27 no.1
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• pp.20-30
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• 2022

Recently, as VR (Virtual Reality) technology has been in the spotlight, 360° panoramic images that can view lively VR contents are attracting a lot of attention. Image stitching technology is a major technology for producing 360° panorama images, and many studies are being actively conducted. Typical stitching algorithms are based on feature point-based image stitching. However, conventional feature point-based image stitching methods have a problem that stitching results are intensely affected by feature points. To solve this problem, deep learning-based image stitching technologies have recently been studied, but there are still many problems when there are few overlapping areas between images or large parallax. In addition, there is a limit to complete supervised learning because labeled ground-truth panorama images cannot be obtained in a real environment. Therefore, we produced three fisheye images with different camera centers and corresponding ground truth image through carla simulator that is widely used in the autonomous driving field. We propose image stitching model that creates a 360° panorama image with the produced fisheye image. The final experimental results are virtual datasets configured similar to the actual environment, verifying stitching results that are strong against various environments and large parallax.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.765-771
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• 2015

In this paper, a dual-band arc-shaped monopole antenna for WLAN(Wireless Local Area Networks) applications. The proposed antenna is based on CPW-fed structure, and composed of two-arc shaped of radiating patch and ground plane. To obtain the optimized parameters, we used the simulator, Ansoft's High Frequency Structure Simulator (HFSS) and found the parameters that greatly effect antenna characteristics. Using optimal parameters, the antenna is fabricated. The numerical and experiment results demonstrated that the propnosed antenna satisfied the -10 dB impedance bandwidth requirement while simultaneously covering the WLAN bands. And measured results of gain and radiation patterns characteristics displayed determined for opeating bands.

• Journal of Biomedical Engineering Research
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• v.10 no.3
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• pp.269-278
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• 1989

The initial impact at foot strike is produced by a slider type mechanical model, which can be measured using a force platform to evaluate various shoes. The lower extremity and foot motion was filmed by a 16mm high speed movie camera and several points on the rear half of the shoe and those near the trochanter and the lateral epicondyle were digitized to provide the linear and angular positions and velocities during impact. With these observed kinematics, a slider type foot strike simulator composed of guide rail and sliding dummy is designed. The simulator system makes the artificial foot of the dummy with running shoe on it to follow the foot strike motion. The dummy has the relevant mass-spring-damper system modeled after McMahon's. The motion of the model is drived by the gravity force and the generated motion alone with the ground reaction forces are monitored by the same procedures afore mentioned producing the initial foot strike impact similar to the onto observed in human gait.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.219-221
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• 1999

HVDC(High Voltage Direct Current) transmission system was constructed between Cheju island and mainland Haenam and has been operating commercially since 1998. But research activities in this area are not so much. That is caused by the facts that HVDC is large scale system and it is not so easy to implement and to test. Though such simulation tools as RTDS(Real Time Digital Simulator) and EMTDC can be useful, these have limitations for actual control and protective system design. Therefore scaled-down HVDC model was developed for the purpose of researches at operating technique, control and protection methods. The design of this model was based on real Cheju-Haenam HVDC system. And additionally faults simulator such as ground fault, short-circuit and change of impedance in transmission line is equipped for analysis of these faults. Control system of the model was implemented fully digitally. So it is very easy for the researchers to develope control and protection algorithm and to test the performance.