• Journal of IKEEE
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• v.15 no.3
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• pp.211-217
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• 2011

The energy of CPV system is different as the altitude and azimuth of solar. In order to The maximum of solar energy density, the tracking system which does there to make be the module and the solar will be able to maintain a normal line is necessary. This paper proposed for GPS solar tracker of stand-alone 60[W] concentrating photovoltaic system. The position algorithm of solar tracker is through the coordinates transformation calculating the altitude and azimuth of the solar.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06a
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• pp.317-318
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• 2010

클라우드 컴퓨팅 서비스를 제공하기 위해서는 클라우드 컴퓨팅에 적합한 데이터 분산 저장 및 병렬 처리가 가능한 IT 인프라 구축이 필수적이다. 이를 위해서 분산 파일 시스템 중 하나인 HDFS(Hadoop File System)와 병렬 데이터 처리를 지원하기 위한 MapReduce 프레임워크 관련 연구가 각광 받고 있다. 하지만 MapReduce 프레임워크를 구성하는 JobTracker 노드는 SPoF(Single Point of Failure)이기 때문에, 작업 도중 JobTracker 노드의 결함이 발생하게 되면 전체 작업이 실패하게 된다. 위와 같은 문제를 해결하기 위해서 본 논문에서는 MapReduce 프레임워크의 JobTracker 노드 결함 발생에 대처할 수 있는 결함허용 메커니즘을 제안하였다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.531-537
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• 2015

In order to maximize power output from the solar panels, one needs to keep the panels aligned with the sun. So solar tracker having high reliability must be designed. This paper cares about the design and evaluation of a two-axis solar tracker system based on fuzzy logic control with LabVIEW. The research focus on planning mechanical parts, making an intelligent controller which controls and monitors all parameters via user interface implemented of a fuzzy decision support system for control of photovoltaic panel movement. We also develop a real solar tracker system and analyze the influence indexes such as environment, weather, season, and light condition. The solar tracker is tested in real condition and all parameters related to the system operation are recorded and analyzed. The developed solar tracking system got a much higher efficiency about 38 % compare to fixed solar panel although the weather condition is affected a lot to the solar panel. So we confirmed the our auto tracking system is more effective and can allow more energy to be produced.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.91-98
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• 2019

The purpose of this study was to develop and test an eye tracker focusing on early childhood participants, based on the characteristics of early childhood eye tracking studies. Eye tracking collects eye movement data of the subject, which provides scientific evidence of human cognition and thinking. The researcher built a Do It Yourself eye tracker camera module from general electronic components, and used Viewpoint analysis software from Arrington Research. The researcher compared the eye tracking data between the DIY eye tracker group and Tobii Pro eye tracker group, which provides a professional eye tracking system. Eye tracking data was collected from 52 five-year old children. The average proportion of valid trials between the two groups was compared with t test, and no significant difference was found. This result indicates that the DIY eye tracker can be used to collect valid eye tracking data from young children under certain research environment.

• Journal of Energy Engineering
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• v.19 no.2
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• pp.128-135
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• 2010

This paper introduces step by step procedures for the fabrication and operation of an embedded solar tracker. The system presented consists of application software, compactRIO, C-series interface module, analogue input module, step drive, step motor, feedback devices and other accessories to support its functional stability. CompactRIO that has a real-tim processor allows the solar tracker to be a stand-alone real time system which operates automatically without any external control. An astronomical method and an optical method were used for a high-precision solar tracker. CdS sensors are used to constantly generate feedback signals to the controller, which allow a solar tracker to track the sun even under adverse conditions. The database of solar position and sunrise and sunset time was compared with those of those of the Astronomical Applications Department of the U.S. Naval Observatory. The results presented here clearly demonstrate the high-accuracy of the present system in solar tracking, which are applicable to many existing solar systems.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.740-745
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• 2023

This study proposes the development of an antenna tracker system using a satellite system to stabilize the communication status of drones and extend the communication distance. The location information of the drone and the ground station was used to maximize communication gain in the general fixed antenna method between the ground station and the drone. We developed a tracker system that can automatically and continuously aim the ground station's antenna at the drone. It is expected that the use of antenna trackers will improve the stabilization of communication conditions and expand the communication distance, thereby leading to the advancement of the drone industry.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.3
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• pp.243-249
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• 2021

The star tracker detects microscopic star light in space and compares it with a stored list of stars to calculate the satellite's position in the inertial coordinate system. If other light, such as the sun or the earth, enters the optical head, the star cannot be recognized and the star tracker cannot be operated. In particular, strong light such as the sun affects not only operation but also the performance of the star tracker. The sun exclusion angle of the star tracker is one of the important factors determining the performance of the star tracker. This paper performs the verification of the star tracker's sun exclusion angle. In order to verify the sun exclusion angle, we predict the sun exclusion time of the star tracker and compare it to the actual sun exclusion time of the GEO-KOMPSAT-2A star tracker. In addition, the performance of the star tracker is analyzed for normal operations against the sun exclusion in the optical head. It shows that the actual sun exclusion is maintained under the range of 26 degrees, the performance requirement of the star tracker, and the star tracker operates normally in spite of the sun exclusion.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.300-308
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• 2010

In order to accelerate the evolution of faster, better, cheaper spacecraft, it is evident that greatly enhanced general-purpose attitude determination methods are needed Currently, star tracker sensors based on charge coupled devices (CCD) or active pixel sensors(APS) enable one to obtain the best spacecraft attitude estimation among the existing sensors for attitude determination. In this paper, basic principles of star tracker technology are explained including major issues arising in design and development of star tracker. Also, an historical overview and worldwide survey associated with various star trackers from star scanner through microelectromechanical system(MEMS)-based star tracker is offered.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.6
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• pp.539-547
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• 2007

In this paper, development and tests of a real-time eye-tracker system are discussed. The tracker system tracks a user's gaze point through movement of eyes by means of vision-based pupil detection. The vision-based method has an advantage of detecting the exact positions of user's eyes. An infrared camera and a LED are used to acquire a user's pupil image and to extract pupil region, which was hard to extract with software only, from the obtained image, respectively. We develop a pupil-tracking algorithm with Kalman filter and grab the pupil images by using DSP(Digital Signal Processing) system for real-time image processing technique. The real-time eye-tracker system tracks the movements of user's pupils to project their gaze point onto a background image.

• Journal of Biomedical Engineering Research
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• v.22 no.6
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• pp.527-534
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• 2001

Conventional stereo image acquisition uses a pair of frame grabbers in the CAS(Computer Assisted Surgery) system. In this Paper, we developed a synchronized stereo image acquisition method with only one frame grabber Two images from left and right camera each other. were merged with different color space without time delay and thus only one frame grabber was enough toy stereo image. Due to this synchronous Property of image acquisition, we can improve spatial revolution on the computation of 3D Position. Furthermore the overall costs for 3D navigator can be down and the extraction time of stereo Position tan be shortened.