• Journal of Aerospace System Engineering
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• v.3 no.2
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• pp.12-19
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• 2009

The research for the fatigue analysis is regarded greatly as important in aerospace field. Moreover, a study on the fatigue characteristic is very actively progressing. In this study, the fatigue life estimation was performed for Flaperon Joint which has FCL(fatigue critical location) of tilt-rotor UAV. The Flaperon Joint should be taken the various loads by several missions profiles of UAV. The fatigue load spectrum of Flaperon Joint is generated by the standard mission segment for the tilt-rotor UAV, and this spectrum is used for the fatigue test and analysis. The in-house fatigue analysis program is applied to calculate the fatigue life based on Stress-Life(S-N) method. The S-N curve is generated from the S-N data of Mil-Handbook by second order polynomial regression method. Moreover, the coefficient of determination is used to ensure how accuracy it has. In addition, the Goodman equation is used to consider the mean stress effect for evaluating more accurate fatigue life. Finally, the result of fatigue analysis is verified by comparing with the fatigue test result for the Flaperon Joint.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1775-1780
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• 2005

One of the most important factors so that mobile objects can achieve their purpose is the information about their positions. In this paper, we propose an improved beacon system, to which ultrasonic sensors are attached, for the indoor localization of mobile objects. We have researched so that it can cover the wider space and estimate more accurate positions than the existent beacon systems. The existent beacon systems have the constraint that one beacon cannot cover wide area since ultrasonic sensors have limits in the angle of signal (beam-angle) on which their signal strength depends. Hence, we used the active beacon which consists of a pan-tilt mechanism and a beacon module. The active beacon system can always aim at mobile objects in order to transmit the strongest signal of the ultrasonic sensors into the objects using the pan-tilt mechanism. In addition, this system is inexpensive because it can decrease the number of beacons by about a half of the beacons of the existent system. Finally, the results show what is the difference between the active beacon system and existent beacon systems, and how accurate it is.

• Fire Science and Engineering
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• v.27 no.6
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• pp.77-82
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• 2013

This research suggested smart fire recognition system which trances firing location with CCD camera with wired/wire-less TCP/IP function and Pan/Tilt function, delivers information in real time to android system installed by smart mobile communication system and controls fire and disaster remotely. To embody suggested method, firstly, algorithm which applies hue saturation intensity (HSI) Transform for input video, eliminates surrounding lightness and unnecessary videos and segmentalized only firing videos was suggested. Secondly, Pan/Tilt function traces accurate location of firing for proper control of firing. Thirdly, android communication system installed by mobile function confirms firing state and controls it. To confirm the suggested method, 10 firing videos were input and experiment was conducted. As the result, all of 10 videos segmentalized firing sector and traced all of firing locations.

• Korean Journal of Cognitive Science
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• v.16 no.4
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• pp.333-349
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• 2005

In this paper, we propose a real tine moving object tracking system based on block-based image processing technique and human visual processing. The system has two nun features. First, to take advantage of the merit of the biological mechanism of human retina, the system has two cameras, a CCD(Charge-Coupled Device) camera equipped with wide angle lens for more wide scope vision and a Pan-Tilt-Zoon tamers. Second, the system divides the input image into a numbers of blocks and processes coarsely to reduce the rate of tracking error and the processing time. Tn an experiment, the system showed satisfactory performances coping with almost every noisy image, detecting moving objects very int and controlling the Pan-Tilt-Zoom camera precisely.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.2
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• pp.135-141
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• 2011

A smart home provides services that its inhabitant needs or wants, by integrating and simultaneously controlling various devices and sensors. In this study, we focused on a smart-home system for people with disabilities and for elderly people. We introduced a new type of system for real-time analysis of body posture of the inhabitants of a smart home. The system includes the concept that offers remote healthcare or medical services by using a 3D tilt sensor for recognizing the static and dynamic postures of inhabitants in real time. It consists of a smart-home server and a 3D tilt sensor, and it uses wireless technology to communicate with the inhabitants and thus enhance their mobility. The smart-home server includes the inference engine that differentiates the dynamic postures from the static ones. Finally, we also demonstrate the usefulness of the proposed system by applying it to a real environment.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.87-90
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• 2004

A numerical analysis was made for the unsteady flow fields of rotor system of a Tilt-Rotor aircraft in cruise mode. The Reynolds-averaged thin-layer Navier-Stokes equations were discretized by Roe's upwind differencing scheme and integrated in time by the LU-SGS algorithm. The computational domain of the rotor system was constructed by six multi-block Chimera grids. Simulated unsteady flow fields of rotating blades were studied in several different view points.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.404-408
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• 2009

Gas pipelines in bridges, roads and subway construction sections can undergo abrupt stress and vibration changes. To protect human life from any gas leakage accidents induced by the abrupt stress and vibration, the gas pipeline system needs to be continuously monitored. The estimation method of pipeline stress using MEMS wireless tilt sensor has been developed and its validity has been evaluated using a lab test bench.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.21-24
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• 2005

Numerical analysis were made for the unsteady flow fields of the rotor system of a Tilt-Rotor aircraft in cruise mode. The Reynolds-averaged thin-layer Wavier-Stokes equations were discretized by Roe's upwind differencing scheme and integrated in time by the LU-SGS algorithm. The computational domain of the rotor system was constructed by seven multi-block Chimera grids. Comparison of pressure coefficient on the surface of the main wing and blades were made for 3cases of advance ratio(0.325, 0.350, 0.375) and thrust and power coefficients for the rotor were compared with experimental data.

• Journal of Astronomy and Space Sciences
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• v.40 no.4
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• pp.237-245
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• 2023

Laser communication has been considered as a novel method for earth observation satellites with generation of high data volume. It offers faster data transmission speeds compared to conventional radio frequency (RF) communication due to the short wavelength and narrow beam divergence. However, laser beams are refracted due to atmospheric turbulence between the ground and the satellite. Refracted laser beams, upon reaching the receiver, result in angle-of-arrival (AoA) fluctuation, inducing image dancing and wavefront distortion. These phenomena hinder signal acquisition and lead to signal loss in the course of laser communication. So, precise alignment between the transmitter and receiver is essential to guarantee effective and reliable laser communication, which is achieved by pointing, acquisition, and tracking (PAT) system. In this study, we simulate the effectiveness of tip/tilt compensation for more efficient laser communication in the satellite-ground downlink. By compensating for low-order terms using tip/tilt mirror, we verify the alleviation of AoA fluctuations under both weak and strong atmospheric turbulence conditions. And the performance of tip/tilt correction is analyzed in terms of the AoA fluctuation and collected power on the detector.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.141-144
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• 2002

This paper describes a new feature based tracking system that can track moving objects with a pan-tilt camera. We extract corner features of the scene and tracks the features using filtering, The global motion energy caused by camera movement is eliminated by finding the maximal matching position between consecutive frames using Pyramidal template matching. The region of moving object is segmented by clustering the motion trajectories and command the pan-tilt controller to follow the object such that the object will always lie at the center of the camera. The proposed system has demonstrated good performance for several video sequences.