• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.452-459
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• 1997

For computer aided design and construction of low noisy power plants, indoor and outdoor noise prediction program has been developed. The program utilizes the predefined data of noise sources and building materials and has the faculty to estimate the source level using the empirical formula in case of the measured data not being available. In the noise prediction, the mutual noise propagation between indoor and outdoor sites are considered. The outdoor noise source in the calculation of geometric divergence effects is modelled as the omni-directional finite line or planar source according to the source geometry and the receiving points. Outdoor noise prediction is carried out to consider the diffraction effect due to plant structures as well as the attenuation effect due to atmospheric absorption and soft ground. The results of indoor and outdoor noise prediction for a recently constructed diesel engine power plant show good agreement with the measured.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.1
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• pp.56-63
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• 2009

This paper describes a general approach for processing data from an omni-directional guided wave transducer array for the rapid inspection of large plate structures. A basic phased array algorithm is presented that can be applied to any array geometry. For guided waves on plate, beam steering algorithm is derived and the corresponding beam pattern is analyzed. The algorithms are applied to simulation and experimental data. The results show well its usefulness in structural applications.

• The Journal of Korea Robotics Society
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• v.3 no.2
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• pp.137-145
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• 2008

We present the initial results of on-going research for building a novel Mobile Haptic Interface (MHI) that can provide an unlimited haptic workspace in large immersive virtual environments. When a user explores a large virtual environment, the MHI can sense the position and orientation of the user, place itself to an appropriate configuration, and deliver force feedback, thereby enabling a virtually limitless workspace. Our MHI (PoMHI v0.5) features with omnidirectional mobility, a collision-free motion planning algorithm, and force feedback for general environment models. We also provide experimental results that show the fidelity of our mobile haptic interface.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.1
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• pp.118-128
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• 2006

This paper deals with auto-landing guidance system design applicable to Smart UAV(Unmanned Aerial Vehicle). The proposed guidance law generates horizontal position, velocity and altitude commands in the longitudinal channel and heading angle command in the lateral channel to track a predetermined trajectory for automatic landing. The longitudinal guidance commands are derived from an approximated dynamic equations in vertical plane. These longitudinal guidance commands are appropriately distributed to each control input as the flight mode of Smart UAV is changed. The concept of VOR(VHF Omni-directional Range) guidance system is applied to generate the required heading angle commands to eliminate the lateral deviation from the desired trajectory. The performance of the proposed guidance system for Smart UAV is evaluated using the nonlinear simulation. Simulation results show that the proposed guidance system for auto- landing provides good tracking performance along the predetermined landing trajectory.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.2
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• pp.180-185
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• 2006

This study has been conducted in order to develop a temperature-controlled round pan diffuser with variable-openings. Flow visualization was performed to investigate the airflow patterns according to gap openings. The velocity profiles were measured using an omni-directional anemometer for two cases, i.e. a horizontal and a vertical discharge conditions. Numerical simulation also confirms there is a narrow range of gap openings where a horizontal discharge shifts to a vertical discharge. The air distribution performance index increases abruptly when the air discharge shifts from vertical to horizontal direction.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.2
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• pp.161-167
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• 2008

This article describes the methods of a decision of the location which user points to move by an optical device like a laser pointer and a moving to that location. Using a conic mirror and CCD camera sensor, a robot observes a spot of user wanted point among an initiative, computes the location and azimuth and moves to that position. This system offers the brief data to a processor with simple devices. In these reason, we can reduce the time of a calculation to process of images and find the target by user point for carrying a robot. User points a laser spot on a point to be moved so that this sensor system in the robot, detecting the laser spot point with a conic mirror, laid on the robot, showing a camera. The camera is attached on the robot upper body and fixed parallel to the ground and the conic mirror.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.219-220
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• 2006

In this paper, we designed and implemented the Dual Band Dipole Antenna with Tapered Microstrip Balun for WLAN Access Point. Two dipole antennas with different resonant frequency and the antenna structure combined additional line were implemented for dual band performance. In order to feed the balun current, the tapered microstrip balun was used. Produced the Dual Band Antenna shows a special quality. The quality is that all VSWR is less than 1.5 in the 2.4GHz and 5GHz frequency bands in 802.11 standards, and it profits not less than 1.7dBi having typical Dipole Antenna pattern the very "a form of 8"pattern and Omni-directional pattern.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.11
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• pp.1127-1133
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• 2003

In this paper, we proposed a novel folded multi-strip monopole antenna whose height is reduced using folded strip structure. It has a broadband characteristic and its measured impedance bandwidth ratio is approximately 1.85 : 1, from 4.55 GHz to 8.4 GHz, for VSWR$\leq$2. Proposed antenna has vertically polarized omni-directional conical beam radiation pattern. It maintains about the same radiation pattern over entire bandwidth.

• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.209-214
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• 2007

In this paper, we proposed a new MANET (Mobile Ad hoc Networks) technology of routing protocol. The MANET has a mobility formation of mobile nodes in the wireless networks. Wireless network have two types architecture: the Tree based multicast and shared tree based. The two kind's architecture of general wireless networks have difficult to solve the problems existing in the network, such as connectivity, safety, and reliability. For this purpose, as using that ADDMRP (Ad hoc network Doppler effect-based for Dynamic Multicast Routing Protocol), this study gives the following suggestion for new topology through network durability and Omni-directional information. The proposed architectures have considered the mobility location, mobility time, density, velocity and simultaneous using node by Doppler effects and improved the performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.499-503
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• 2013

자동차를 위한 전방향(omni-directional) 감시 시스템, 로봇의 시각 역할 등 다양한 비전 시스템에서 카메라가 장착되어 사용되고 있다. AVM(Around View Monitoring) 시스템에서 그리드 패턴의 코너를 검출하기 위해서는 먼저, 광각 카메라에서 획득한 비선형적인 방사 왜곡을 가진 영상의 왜곡 보정 작업을 수행하여야 한다. 이후에 왜곡이 보정된 영상 내부의 그리드 패턴 각 코너들을 자동으로 검출하기 위해서 Sub-Pixel, 허프 변환 등의 여러 가지 방법이 있으며 현재 출시된 AVM 시스템에 직선이나 교점 및 코너 검출을 위해 사용되고 있다. 본 논문에서는 왜곡 보정 영상을 입력 영상으로 받아 그리드 패턴의 코너를 자동으로 검출하는 프로그램을 설계한다. 제안하는 코너 검출 방법을 직접 구현하여 성능을 평가함으로써 AVM 시스템에서 코너를 검출하는 부분에 적용시킬 수 있음을 보인다.