• Journal of Advanced Navigation Technology
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• 제6권3호
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• pp.241-250
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• 2002

This paper presents a way to maximize transmission efficiency and reception ability through transmission diversity technology, which can be adapted to wireless multimedia OFDM system. The presented method is a comparative analysis between a case where parameter ${\alpha}$ for time average is 0.3, 1 with consideration of channel presumption with two types of rms delayed spread, which is 50nsec, 150nsec, for the performance analysis of STTC(Space-Time Trellis Code) using time-space ciphering method appropriate for MIMO channel, and performance in the case where presumed channel value from long training column section is applied to according frame in a single frame. The result showed that BER brought SNR improvement of 1.0 dB in $10^{-3}$ when ${\alpha}$ was 0.3 than using only the long training column, and showed increase of general performance improvement for the sake of time average rather than the case without.

• Journal of Advanced Navigation Technology
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• 제21권6호
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• pp.585-592
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• 2017

Recently, as the air traffic volume has been explosively increased, various studies are being conducted to increase the air passenger capacity. In order to compensate the limitation of the separation distance on the aerodrome established on the basis of existing VOR / DME equipment, GNSS utilizing satellite is considered. In addition, we are trying to obtain more precise location information by using SBAS, a system that can correct GNSS error. ICAO recommends introducing SBAS until 2025, and Korea has also started to develop KASS, a Korean SBAS since 2014. Therefore, in this paper, we analyze the interference threshold for the measurement items and the receiving antenna gain according to the elevation angle of the satellite receiving antenna.

• Journal of Advanced Navigation Technology
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• 제10권4호
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• pp.319-326
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• 2006

In this paper, a fuzzy inference control system is proposed for a turbojet engine with fuel flow control input only. The proposed control system provides a practical fuel flow control method to prevent surge or flame out during engine acceleration or deceleration. A fuzzy logic is designed to obtain the fast acceleration and deceleration of the engine under the condition that the operating point should stay between the surge line and flame out control line. With using both engine rotating speed error and surge margin as fuzzy input variables, the desired engine rotating speed can be achieved to rapidly follow the engine control line without engine stall. Computer simulation using the MATLAB is realized to prove the proposed control performance to the turbojet engine which is linear modelized using DYGABCD program package.

• Journal of the Korea Society of Computer and Information
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• 제24권10호
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• pp.1-9
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• 2019

Fighter pilots are taking 'Advanced Pilot Training' courses to perform their missions perfectly even under adverse conditions. However, there are accidents that fall due to problems with the human body's equilibrium in the acceleration of flight, falling into the 'Vertigo, Spatial disorientation' phenomenon. As such, accidents that fighters fall due to spatial disorientation frequently occur not only in Korea but also abroad. In this study, we implemented the 'Vertigo' warning function in the fighter. First, we analyzed the aircraft's mission computer and the currently implemented warning functions. And we studied the coordinate system to utilize the aircraft attitude information. Based on this, we wanted to provide a visual warning to the HUD when the fighter flies over a certain time in the inverted flight position. Implementing this feature is expected to improve pilot flight safety. In addition, based on the results of this study, we propose a method to implement warning functions through linkage with other subsystems.

• Journal of IKEEE
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• 제26권2호
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• pp.257-264
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• 2022

As it takes a lot of time and money to develop an aircraft, an environment for renovating and using existing operating aircraft has been created. As a result, many old aircraft were renovated, and due to the aging of the aircraft, more demanding cable requirements were required for renovation projects, and as the number of equipment inside the aircraft gradually increased, the difficulty of system integration increased. In order to solve the difficulties of system integration through systematization of verification procedures, this paper explains VSWR, I-loss, which are the main indicators of antenna cable modification, and explains DTF, one of the problem detection methods. It also explains the elements required for cable design, the environment to be measured, and procedures, and introduces the overall process and effect of antenna cable improvement through demonstration cases.

• Journal of the Korea Society of Computer and Information
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• 제27권12호
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• pp.93-100
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• 2022

In this paper, we propose a mobile app for personalized rehabilitation exercise coaching and management service using an edge computing-based personalized exercise information collection system. The existing management method that relies on user input information has difficulty in examining the actual possibility of rehabilitation. In this paper, we implement an application that collects movement information along with body joint information through image information analysis based on edge computing at a remote location, measures the time and accuracy of the movement, and provides rehabilitation progress through correct posture information. In addition, in connection with the measurement equipment of the rehabilitation center, the health status can be managed, and the accuracy of exercise information and trend analysis information is provided. The results of this study will enable management and coaching according to self-rehabilitation exercises in a contactless environment.

• Journal of the Korea Society of Computer and Information
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• 제29권4호
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• pp.55-62
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• 2024

In this paper, we propose a thin-film hydroponic plant cultivator using HMI display and IoT technology. Existing plant cultivators were difficult to manage due to soil-based cultivation, and it was difficult to optimize environmental conditions due to the open cultivation environment. In addition, there are problems with plant cultivation as immediate control is difficult and growth of plants is delayed. To solve this problem, a cultivation environment was established by connecting the MCU and sensors, and the environment information could be checked and quickly controlled by linking with the HMI display. Additionally, a case was applied to minimize changes in environmental information. Implementation of a thin-film hydroponic cultivation system made soil management easier, improved functionality through operation and control, and made it easy to understand environmental information through the display. The effectiveness of rapid growth was confirmed through crop cultivation experiments in existing growers and hydroponic growers. Future research directions will include optimizing growth information by transmitting and storing cultivation environment information and linking and comparing growth information using vision cameras. It is expected that this will enable efficient and stable plant cultivation.

• The Journal of the Convergence on Culture Technology
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• 제10권4호
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• pp.589-594
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• 2024

In this paper, we introduce the results of the Sounding Rocket LTE communication test using the LTE-Cat.M1 module. The developed LTE data transmission/reception system consists of Mission-Mounted Equipment(Payload) and Ground Observation Equipment(GOE), and the delay rate was secured based on the time between data measured when received from the GOE by constantly transmitting data from the Payload at a speed of 10 Hz. In order to increase the accuracy of the actual flight test, ground network delay rate tests, hardware internal delay rate tests, and ground tests were performed. As a result of the flight test, it was confirmed that the handover failed in the upward phase and the communication was lost for 13 seconds, and then the parachute was deployed and the communication was reconnected in a situation with a constant positional displacement. LTE-Cat.M1 technology is expected to be utilized for descent phase observation missions or data backup during Sounding Rocket missions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제50권4호
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• pp.259-267
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• 2022

The existing method of deriving the fail-safe design requirements for the domestic developed rotary-wing aircraft system may miss the factors that cause critical system function failures, when being applied to the latest integrated avionics system. It is because the existing method analyzes the severity effect of the failures caused by a single item. To solve the issue, we present a systematic analysis procedure for deriving fail-safe design requirements of system architecture by utilizing functional hazard assessment and development assurance level analysis of SAE ARP4754A, international standard for complex system development. To demonstrate that our proposed procedure can be a solution for the aforementioned issue, we set up experimental environments that include common factors that can cause critical function failures of a system, and we conducted a cross-validation with the existing method. As a result, we showed that the proposed procedure can identify the potential critical common factors that the existing method have missed, and that the proposed procedure can derive fail-safe design requirements to control the common factors.

• Journal of the Korea Society of Computer and Information
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• 제27권8호
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• pp.77-84
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• 2022

In this paper, we propose a system for monitoring air pollutants such as fine dust using an unmanned aerial vehicle capable of autonomous navigation. The existing air quality management system used a method of collecting information through a fixed sensor box or through a measurement sensor of a drone using a control device. This has disadvantages in that additional procedures for data collection and transmission must be performed in a limited space and for monitoring. In this paper, to overcome this problem, a GPS module for location information and a PMS7003 module for fine dust measurement are embedded in an unmanned aerial vehicle capable of autonomous navigation through flight information designation, and the collected information is stored in the SD module, and after the flight is completed, press the transmit button. It configures a system of one-stop structure that is stored in a remote database through a smartphone app connected via Bluetooth. In addition, an HTML5-based web monitoring page for real-time monitoring is configured and provided to interested users. The results of this study can be utilized in an environmental monitoring system through an unmanned aerial vehicle, and in the future, various pollutants measuring sensors such as sulfur dioxide and carbon dioxide will be added to develop it into a total environmental control system.