• Journal of Astronomy and Space Sciences
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• v.39 no.3
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• pp.109-116
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• 2022

The small-scale magnetospheric and ionospheric plasma experiment (SNIPE) is a mission initiated by the Korea Astronomy and Space Science Institute (KASI) in 2017 and comprises four 6U-sized nano-satellites (Korea Astronomy and Space Science Institute Satellite-1, KASISat-1) flying in formations. The main goal of the SNIPE mission is to investigate the space environment in low Earth orbit at 500-km. Because Iridium & GPS Board (IGB) is installed on the KASISat-1, a communication simulation is required to analyze the contact number and the duration. In this study, communication simulations between the Iridium satellite network and KASISat-1 are performed using STK Pro (System Tool Kit Pro Ver 11.2) from the AGI (Analytical Graphics, Inc.). The contact number and durations were analyzed by each orbit and date. The analysis shows that the average access number per day is 38.714 times, with an average of 2.533 times per orbit for a week. Furthermore, on average, the Iridium satellite communication is linked for 70.597 min daily. Moreover, 4.625 min is the average duration of an individual orbit.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.9
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• pp.746-756
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• 2017

An algorithm is developed to generate measurement data of deep space network for Korea Pathfinder Lunar Orbiter (KPLO) mission. The algorithm can provide corrected measurement data for the Orbit Determination (OD) module in deep space. This study describes how to generate the computed data such as range, Doppler, azimuth angle and elevation angle. The geometric data were obtained by General Mission Analysis Tool (GMAT) simulation and the corrected data were calculated with measurement models. Therefore, the result of total delay includes effects of tropospheric delay, ionospheric delay, charged particle delay, antenna offset delay, and tropospheric refraction delay. The computed measurement data were validated by comparison with the results from Orbit Determination ToolBoX (ODTBX).

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.287-298
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• 2023

The purpose of this study is to analyze the compensation law for Special Mission Executors enacted to compensate for sacrifices for the state based on the policy framework proposed by Gilbert and Terrell and to present the limitations and development directions of the compensation policy. In particular, this study presents the characteristics of each dimension of the policy through the bases of social allocation, the types of social provisions, the strategies for the delivery, and the ways to finance. Through the analysis, We deduce problems of the compensation law for Special Mission Executors. Representative limitations of the compensation policy can be summarized as follows. Due to extreme selectivism, the limitations are the narrow selection criteria of the targets, the benefits which are not out of proportional to contributions, delayed benefits and the decrease in the size of public resources. These limitations suggest that the compensation policy for Special Mission Executors does not contain the significance of the Patriots and Veterans Affairs Policy. The value the Patriots and Veterans Affairs can be considered as a means for repaying the contributions who sacrificed for the nation. Therefore, the government needs to make efforts to develop a policy with the true significance of the Patriots and Veterans Affairs.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.28.2-28.2
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• 2008

Recently, star sensors have been successfully used as main attitude sensors for attitude control in many satellites. This research presents the star visibility analysis for star trackers and the goal of this analysis is to make sure that the star tracker implementation is suitable to the mission profile and scenario and satisfies the requirement of attitude orbit control system. As a main optical attitude sensor imaging stars, accomodations of a star tracker should be optimized in order to improve the probability of the usage by avoiding the blinding (the unavailability) by the Sun and the Earth. For the analysis, a statistical approach and a time simulation approach are used. The statistical approach is based on the generation of numerous cases, to derive relevant statistics about Earth and Sun proximity probabilites for different lines of sight. The time simulation approach is performed for one orbit to check the statistical result and to refine the statistical result and accomodations of star trackers. In order to perform simulations first of all, an orbit and specific mission profiles of a satellite are set, next the earth proximity probability and the sun proximity probability are calculated by considering the attitude maneuvers and the geometry of the orbit, and then finally the unavailability positions are estimated. As a result, the optimized accomodations of two star trackers are suggested for the low earth orbit satellite.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.4
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• pp.508-519
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• 2018

In order to design the hull form of an underwater vehicle in the conceptual design phase, the dynamic characteristics depending on the hull form parameters should be identified. Course-keeping stability, turning ability, yaw-checking ability, and mission competence are set to be the indices of the dynamic characteristics, and the geometric parameters for the bare hull and rudder are set to be the hull form design parameters. The total sensitivity of the dynamic characteristics with respect to the hull form parameters is calculated by the chain rule of the partial sensitivity of the dynamic characteristics with respect to the hydrodynamic coefficients, and the partial sensitivity of the hydrodynamic coefficients with respect to the hull form parameters. Based on the sensitivity analysis, important hull form parameters are selected, and those optimal values to satisfy the required intercept time of mission competence of a specific underwater vehicle and turning rate are estimated.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.155-161
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• 2022

Until now, many leadership styles have focused only on behavioral characteristics or skills. However, genuine leadership focuses on the essence of leadership. This study intends to analyze the effects of genuine leadership, the main body leading the corporate organization, on the organization's influence in order to achieve the organizational mission. In order to examine the relationship between genuine leadership, job satisfaction, and organizational commitment after deriving a research model as a method of research, we conducted a regression analysis after frequency analysis, validity, and reliability analysis to examine the effect of genuine leadership on organizational commitment and job satisfaction. looked at the As a result of the analysis, it was found that leadership had a positive effect on organizational commitment and job satisfaction.

• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.37-44
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• 2011

COMS(Chollian) satellite which was launched on June 26, 2010 has three payloads for Ka-band communications, geostationary ocean color imaging and meteorological imaging. In order to make efficient use of the geostationary satellite, a concept of mission operations has been considered from the beginning of the satellite ground control system development. COMS satellite mission operations are classified by daily, weekly, monthly, and seasonal operations. Daily satellite operations include mission planning, command planning and transmission, telemetry processing and analysis, ranging and orbit determination, ephemeris and event prediction, and wheel off-loading set point parameter calculation. As a weekly operation, North-South station keeping maneuver and East-West station keeping maneuver should be performed on Tuesday and Thursday, respectively. Spacecraft oscillator updating parameter should be calculated and uploaded once a month. Eclipse operations should be performed during a vernal equinox and autumnal equinox season. In this paper, operational validations of the major functions in COMS SGCS are presented for the first three month of in-orbit test operations. All of the major functions have been successfully verified and the COMS SGCS will be used for the mission operations of the COMS satellite for 7 years of mission life time and even more.

• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.427-439
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• 2021

This study surveyed the recognition on the Korean education for specific purposes targeting student-teachers majoring Korean language education in a Cyber University located in Seoul. 50 among 57 students taking the class participated in this survey. The participants were the students-teachers interested in Korean education for the mission purposes and took the class during the second term in 2020. At the end of the term they participated in this survey. 6 items were objective and 4 items were narrative. Among the narrative ones, one was excluded from analysis. The objective items were investigated by descriptive statics and the narrative items were analyzed with qualitative approach. As a result, most of the participants preferred the combined textbooks with others such as the ones for general and mission purposes rather than the bibles only. They had positive opinions on using the bibles, but proposed that the bibles themselves are not the best choice for improving communicative competence and the text combination is the better choice because of the difficulty of the bibles, the lack of teachers' competence, and the learners' needs. However, while taking this class, they became to be aware of the possibilities of the bibles as textbooks, to possess the concern about the mission areas, to consider the possibilities of application and the educational methods in it, and to reflect the ways for self development. This study suggested several points as follows: the development of diverse textbooks according to situations and learners, two directions of teacher education and the cooperative works, and the necessities of the related departments and classes with mission purposes.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.176-184
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• 2010

The power simulator for a LEO satellite is a useful tool to analyze mission validity and energy balance for various mission scenarios by estimating power generation, power consumption, depth of discharge, bus voltage, charging/discharging current, etc. In this paper, it is described the calculation algorithm of the solar array (SA) power, the satellite load power and the battery modeling method to develop a satellite power simulation. To simulate the SA power generation, three different operation modes (DET, MPPT, CV) of SAR (Solar Array Regulator) are considered with a SA model. The satellite load power is estimated using the satellite unit power database, the unit on/off configuration at some satellite operation modes. The bus voltage and battery charging/discharging current at the specific DoD (Depth of Discharge) are calculated based on the battery characteristics. By this satellite power simulator, it can be conveniently analyzed the energy balance and the validity of a planned mission of a LEO satellite.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.319-326
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• 2013

This paper describes the orbital dynamics operation results for the launch and early operations phase (LEOP) of KOMPSAT-3, which was successfully launched on May 18, 2012. At the initial phase, operational orbit determination was carried out using ground tracking data and GPS navigation solution. And, both in-plane and out-of plane maneuvers were executed in order to change the orbit from the injection orbit to the mission orbit. In addition, the accuracy of precise orbit determination was indirectly evaluated by overlapping method using GPS raw data of KOMPSAT-3 and international GNSS service data from worldwide-distributed ground stations. Currently, KOMPSAT-3 is operated in pre-defined mission orbit, and its various kinds of orbit data are generated and distributed to support the normal mission operations.