• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.1
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• pp.113-119
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• 2003

During the mission operation time, it is very important to estimate the spacecraft propellant remaining as accurately as possible. This is because the quantity of propellant is related directly to how long the satellite can be operated ín orbit. There are two different methods for spacecraft propellant gauging; the PVT method and the book-keeping method. This paper describes the characteristics and applications of these methods using the flight operation data of KOMPSAT-1. Additionally, propellant consumption rates in delta-V maneuvering and each attitude control submode are analyzed according to spacecraft operation modes. The earth search submode shows the highest propellant consumption rate.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.5
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• pp.393-400
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• 2017

A virtual simulation test program to carry out the handling qualities of unmanned Rotorcraft has developed by using the MATLAB GUIDE(Graphic User Interface Development Environment). The handling quality evaluation program based on ADS-33E contributes to design the flight control system and to evaluate handling qualities. In addition, Linear Quadratic Tracker with Integrator(LQTI) attitude controller based on Linear Quadratic Regulator(LQR) for to rotorcraft BO-105C and the effects of the handling qualities is analyzed change to weight matrices of the Q and R.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.12
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• pp.986-993
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• 2018

Lateral thrust jet has better maneuverability performance than the control surface like the conventional fin for attitude control or orbital transition of guided weapons. However, in the supersonic region, a jet interaction flow occurs due to the lateral thrust jet during flight, and a complicated flow structure is exhibited by the interaction of the shock wave, boundary layer flow, and the vortex flow. Especially, hit-to-kill interceptors require precise control and maneuvering, so it is necessary to analyze the effect of jet interaction flow. Conventional jet interaction analyses were performed under low altitude conditions, but there are not many cases in the case of medium altitude condition, which has different flow characteristics. In this study, jet interaction flow analysis is performed on the lateral jet controlled interceptor operating at medium altitude. Based on the results, the structural characteristics of the flow field and the changes of aerodynamic coefficient are analyzed.

• Journal of Convergence for Information Technology
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• v.9 no.4
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• pp.68-77
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• 2019

The purpose of this study is to identify the optimal model to explain safety behavioral intention according to the recognition of safety communication in cabin through comparison of Planned behavioral theory and Triandis' theory of interpersonal behavior. In order to accomplish the study purpose, research model and hypothesis were established based on the previous research. As a result of the analysis, it was found that attitude and Perceived Behavioral Control had a positive effect on the safety behavioral intention. Triandis theory shows that social factors and habits have a positive impact on safety behavioral intention. In addition, A comparison of the two models confirms that both psychological processes of recognition and emotion are accompanied by the relationship between safety information awareness and safety behavioral intention.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.9
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• pp.81-90
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• 2016

Recently drones have become popular enough to be one of the hobby. The drone refers to an unmanned aerial vehicle which can fly and be steered by a radio wave without a pilot and it has a airplane or helicopter shape. The drone was first started to be used from military purpose, but its usage has been expanded to the private such as construction site, crop-dusting, field discovery, freight shipping and drones to prevent cheating. However the drone that we can see often in the market is expansive, hard to be repaired when it broken down and has a discomfort of the short flight time. In this paper, to solve an uncomfortable talk on the cheap 8-bits microcontrollers ATmega128 Using drone for implementation. Axes gyroscope and accelerometers mcu between posture an attitude control, communications through drone control, pid. Receiver input them into transmitter signals of movements to control drone c the programming was implemented in on the basis of language. drone using ATmega128 microcontroller is possible hovering, By utilizing a pin that are not required for control it can be used as a drone for a variety of uses.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.41-51
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• 2018

Downwash from helicopter rotor blades and external winds from various maneuvering make an unguided rocket change its trajectory and range. For the prediction of the trajectory and range, it is essential to consider the downwash effect. In this study, an algorithm was developed to calculate 6-Degree-Of-Freedom(6 DOF) forces and moments exerting on the rocket, and total flight trajectory of a 2.75-inch unguided rocket in a helicopter downwash flow field. Using Actuator Disk Model(ADM) analysis result, the algorithm could analyze the entire trajectory in various initial launch condition such as launch angle, launch velocity, and external wind. The algorithm that considered the interference between a fuselage and external winds could predict the trajectory change more precisely than inflow model analysis. Using the developed algorithm, the attitude and trajectory change mechanism by the downwash effect were investigated analyzing the effective angle of attack change and characteristics of pitching stability of the unguided rocket. Also, the trajectory and range changes were analyzed by considering the downwash effect with external winds. As a result, it was concluded that the key factors of the rocket range change were downwash area and magnitude which effect on the rocket, and the secondary factors were the dynamic pressure of the rocket and the interference between a fuselage and external winds. In tailwind case which was much influential on the range characteristics than other wind cases, the range of the rocket rose as increasing the tailwind velocity. However, there was a limit that the range of the rocket did not increase more than the specific tailwind velocity.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.106-106
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• 2014

SIGMA (Scientific cubesat with Instrument for Global Magnetic field and rAdiation)는 근 지구공간에서 우주방사선량 측정과 자기장 변화 검출의 과학적 목적과 교육적 목적을 가지고 개발하고 있는 초소형 큐브위성이다. $100mm{\times}100mm{\times}340.5mm$의 크기로 약 3.6 kg의 무게를 가지며, 탑재체는 방사선에 대하여 인체와 동일한 산란 흡수 특성을 가진 Tissue Equivalent Proportional Counter (TEPC)와 자기장 측정을 위한 Magnetometer (Mag)이다. 위성체는 구조계, 자세제어계, 전력계, 명령 및 데이터처리계, 통신계로 구성되어있다. 구조계는 위성의 뼈대인 Chassis와 Mag deployer로 이루어져있고, 위성의 안정적인 자세유지를 목적으로 Attitude Control System (ACS) Board와 Torque Coil이 자세제어계로 구성된다. 전력의 생산과 공급 및 충전은 태양전지판과 Electrical Power System (EPS), 리튬 배터리로 구성된 전력계에서 이뤄지며, 명령 및 데이터처리계는 On Board Computer (OBC)와 Instrument Interface board (IIB)를 중심으로 서브시스템의 명령체계와 데이터처리를 다룬다. 통신계는 Uplink인 VHF 안테나와 Downlink인 UHF, S-band 안테나로 구성되며 지상과 명령을 송수신한다. SIGMA는 타임인터럽트 기능을 활용한 Flight Software (FSW)로 운용되며 임무에 따른 6가지 모드의 시나리오로 위성을 운용한다. 이에 SIGMA의 개발과 테스트 결과를 소개한다. 본 큐브위성 개발기술을 바탕으로 향후 천문관측용 위성에도 활용할 예정이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.493-503
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• 2021

In this study aviation authority officials were classified into four cultural groups according to culture theory, and then questioned to determine the effects of cultural bias on their social acceptance of a new air traffic flow management system. Based on previous studies, cultural biases were categorized as egalitarianistic, individualistic, fatalistic, and hierarchical, and social acceptances were considered to be influenced by four variables, that is, perceptions of usefulness, work attitude, intention to use, and behavior (job absorption). Empirical analysis showed that hierarchy had a significant positive effect on social acceptance, and egalitarianism was found to have a significant positive effect on social acceptance with 95% credibility. We propose the organizational culture of Korean government be changed to accept the diverse opinions of government officials during the implementation phase of the new system recommended by ICAO.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.578-588
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• 2019

As the service industry develops, service quality, customer satisfaction, and human resource management are considered priorities in modern management to maintain a company's growth. Therefore, understanding the strategic importance of service marketing is an essential task for modern companies. This study examined the relationship between the internal service quality of employees in the organization and customer orientation through organizational effectiveness. In the case of an airline, a service can be defined as an interaction between an external customer and an internal customer service provider. This interaction significantly affects the behavior and attitude of the employees. Based on the results, empowerment has a significant influence on the internal service quality, but it has no significant effect on customer orientation. As the relationship between department and employees improved, the more confident staff showed an improved ability to perform their work. Therefore, it is important that the organizational structure and the reporting system are as concise and clear as possible to allow employees to accurately recognize the authorities and responsibilities assigned to them and have autonomy and discretion in the framework.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1479-1488
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• 2022

Accidents in which oil spills occur intermittently in the ocean due to ship collisions and sinkings. In order to prepare prompt countermeasures when such an accident occurs, it is necessary to accurately identify the current status of spilled oil. To this end, the Coast Guard patrols the target area with a fixed-wing airplane or helicopter and checks it with the naked eye or video, but it was difficult to determine the area contaminated by the spilled oil and its exact location on the map. Accordingly, this study develops a technology for direct ortho-rectification by automatically geo-referencing aerial images collected by the Coast Guard without individual ground reference points to identify the current status of spilled oil. First, meta information required for georeferencing is extracted from a visualized screen of sensor information such as video by optical character recognition (OCR). Based on the extracted information, the external orientation parameters of the image are determined. Images are individually orthorectified using the determined the external orientation parameters. The accuracy of individual orthoimages generated through this method was evaluated to be about tens of meters up to 100 m. The accuracy level was reasonably acceptable considering the inherent errors of the position and attitude sensors, the inaccuracies in the internal orientation parameters such as camera focal length, without using no ground control points. It is judged to be an appropriate level for identifying the current status of spilled oil contaminated areas in the sea. In the future, if real-time transmission of images captured during flight becomes possible, individual orthoimages can be generated in real time through the proposed individual orthorectification technology. Based on this, it can be effectively used to quickly identify the current status of spilled oil contamination and establish countermeasures.