• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.7
• /
• pp.551-556
• /
• 2018

A lot of hardwares are allocated on the satellite to perform the attitude control. Sun sensor is very important hardware to acquire the initial attitude after separation from launcher and to maintain the safety attitude from the satellite anomaly operation. So the allocation of the sun sensor to acquire the field of view and the attitude control design using it, are critical work in the beginning of development. Number of Sun sensor for GEO-KOMPSAT2 is reduced with respect to COMS due to star tracker usage. The additional sun sensor using COMS heritage is considered. In this paper, it is described the analysis and the results on the method for the safety improvement which is to enlarge the field of view and to consider the harness connection of P/R-side of the sun sensor.

• Aerospace Engineering and Technology
• /
• v.4 no.2
• /
• pp.60-64
• /
• 2005

STSAT-2 will demonstrate the scientific mission(acquisition of brightness temperature of the earth at 23.8 GHz and 37 GHz) and spacecraft technologies(laser ranging, frame-type satellite structure, Dual-head star tracker, CCD sun sensor, pulsed plasma thruster, etc.). In this paper STSAT-2 satellite system is described. It includes the definition of the system and the overview of payloads and BUS.

• Journal of Multimedia Information System
• /
• v.4 no.4
• /
• pp.285-288
• /
• 2017

In this paper, we propose a vision-based object detection and tracking system using online learning. The proposed system adopts a feature point-based method for tracking a series of inter-frame movement of a newly detected object, to estimate rapidly and toughness. At the same time, it trains the detector for the object being tracked online. Temporarily using the result of the failure detector to the object, it initializes the tracker back tracks to enable the robust tracking. In particular, it reduced the processing time by improving the method of updating the appearance models of the objects to increase the tracking performance of the system. Using a data set obtained in a variety of settings, we evaluate the performance of the proposed system in terms of processing time.

• 제어로봇시스템학회:학술대회논문집
• /
• 1995.10a
• /
• pp.110-114
• /
• 1995

This paper presents the on-board attitude determination algorithm for LEO (Low Earth Orbit) three-axis stabilized spacecraft. Two advanced star trackers and a three-axis Inertial Reference Unit (IRU) are assumed to be attitude sensors. The gyro in the IRU provides a direct measurement of the attitude rates. However, the attitude estimation error increases with time due to the gyro drift and noise. An update filter with measurements of star trackers and/or sun sensor is designed to update these gyro drift bias and to compensate the attitude error. Kalman Filter is adapted for the on-board update filter algorithm. Simulation results will be presented to investigate the attitude pointing performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2003.10a
• /
• pp.311-314
• /
• 2003

This paper describes a virtual instrument system with faulty sensor reconstruction mechanism based on personal computer. This system consists of sensor control board using 16bit RISC machine, error signal reconstruction algorithm based on principal component analysis and auto tunned GUI interface according to the attached sensors. USB module is used for fast communication between PC and sensor controller. To show the veridity of the proposed system, the proposed system was applied to the developed sun tracker with 8 solar sensors.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2016.10a
• /
• pp.184-187
• /
• 2016

본 연구는 손목 착용형 활동 측정기로부터 수집된 활동 강도 값을 기반으로 사용자의 수면 상태를 파악하는 방법을 제시한다. 수집된 활동 강도 값은 하루 전체에서 1분 단위로 손목의 움직임의 크기에 따라 측정되는 값으로 수면과 활동 시 그 값의 차이를 나타낸다. 본 연구는 활동 강도에 따라 수면 상태를 검출하고 검출된 수면 상태의 지속시간에 기반을 두어 수면 상태를 보정한다. 3명의 사용자로부터 하루씩 수집된 활동 강도 값에서 검출된 수면 시간은 실제 수면 시간에 대비하여 약 99.35%의 정확도를 갖는다.

• Information and Communications Magazine
• /
• v.31 no.12
• /
• pp.64-71
• /
• 2014

요즘 많은 인기를 끌고 있는 핏빗(Fitbit)과 같은 액티비티 트래커(Activity tracker)와 곧 출시될 애플 워치(Apple watch)와 같은 스마트 시계 등에서 얻을 수 있는 운동 또는 활동량 데이터와 맥박과 같은 건강 데이터를 플랫폼을 통하여 획득하고 이를 기반으로 건강을 관리하고자 하는 노력이 다양한 곳에서 시도되고 있다. 이와 같이 미국, 유럽의 정부와 애플, 구글, 마이크로소프트, 삼성과 같은 많은 글로벌 기업 등이 앞다투어 개인 건강 관리를 위한 기술을 개발하고 있고, 많은 기업들이 건강 관련 기기와 서비스를 상용화하여 내놓고 있다. 이러한 획득 가능한 데이터로부터 전통의학인 한의학 기반의 건강 관리를 위하여 한의학적으로 의미있는 개인 건강 데이터를 수집하려는 기술에 대하여 알아본다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.4 no.4
• /
• pp.258-263
• /
• 2011

In this paper, a high quality battery charge-discharge controller for new & renewal energy power generation system is designed. The proposed new controller has a function to manipulate the battery charging current precisely and it is suitable for various batteries including Lead-Acid battery generally used for solar power generation system. LCD display function is implemented to enhanced the user's convenience and minimization of standby power consumption is realized by optimal design using CAD tools.

• KIEAE Journal
• /
• v.10 no.4
• /
• pp.137-145
• /
• 2010

Active sunlighting systems have been applied to deliver sunlight into the indoor space where natural light is insufficient, mainly because of the congested high-rise buildings in urban areas. Among various active sunlighting systems, a mirror sunlighting system which is simple structure and economically reasonable has been widely used in different types of spaces such as underground, north facing place and atrium. This study was to evaluate the mirror sunlighting systems, which were consisted of the first mirror of $3.5m{\times}2.5m$, the eight sets of the second mirrors of $1.0m{\times}1.25m$ and a sun tracker. Ten sets of the systems were installed for 40 apartment living rooms, the configuration of $3.5m(W){\times}4.0m(D){\times}2.5m(H)$ where sunlighting were not possible due to high retaining walls located in the front of the living rooms. The 45 HOBO data logger sensors for the indoor illuminance were equipped and 2 Li-cor photometers for outdoor illuminance. Both indoor and outdoor horizontal illuminances were monitored every second from 9am to 3pm on 17 January 2010 under clear sky condition. The results showed that the indoor illuminance of installed mirror sunlighting system was significant relationship with outdoor illuminance and increased the indoor illuminance level by 4.2 times on the whole floor space, by 8 times on the sun patch space of 6m2 and even by 2 times on the no sun patch space. In addition, the luminous conditions of the living room under real sky conditions met the KS recommendation for difficult task (600-1000-1500 lux) such as sewing and reading on whole floor space and sun patch space. It was proved that the benefits of mirror sunlighting systems included an effective technology for penetrating daylight into indoors where sunlighting was not possible and improving occupants' satisfaction and health, and contributing to energy saving in apartments during daytime.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.2
• /
• pp.672-680
• /
• 2017

A solar photovoltaic system is composed of a module mounting structure, supporting trunk, and a control unit that supplies generated electrical power to an external power grid or a load. The efficiency of the system depends on the incident solar light, so the mounting structure is installed to face the sun. However, because the sun always moves, systems that track the sun have better efficiency than fixed systems. The structure experiences wind pressure, snow load, seismic load, and structure weight. The wind pressure has the most serious effect on the structure. The pressure was obtained using finite element method for various gaps between modules and angles between the panel and the ground. The wind pressure is lowest when the gap is zero, and it increases with the inclination angle. Based on the results, a mounting structure module was designed.