• Journal of Advanced Navigation Technology
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• v.19 no.1
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• pp.15-21
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• 2015

WA-DGNSS is a system to service for users using a satellite which received correction data from ground station that calculates the relative errors of the tracked GNSS signals and sends to a satellite. Users are guaranteed the reliability of the GNSS signal and the accuracy of positioning. ICAO recommends the application of WA-DGNSS for the airplane taking off and landing process. In this paper, we suggests methods to verify of the pre-developed WA-DGNSS reference software constituting modules and an integration test process refer to the RTCA DO-278 which is a document for the development process of an aeronautics software. Also, we statistically verified the reference software test through our methods. And then, we confirmed to performance the function of the reference software properly.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.97-104
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• 2018

In the conventional direction finding, the antenna is installed at a high position on the ground to detect the position of the target with the environment of the LOS(Line of Sight) as much as the signal receiving environment. However, in order to configure such environment, high cost and installation time were required. In this paper, we use TDOA(Time Difference of Arrival) technique to utilize drones in direction finding, so that four drones can be used for directions finding simulation. Simulations based on drone and TDOA direction finding were constructed using additional signal processing Taylor series and Exact Interactive Algorithm. In the simulation, the receiving power is defined by using the 800MHz path-loss model using the GPS information of the ground direction detection, and the position estimation performance is analyzed when the TDOA technique, the Taylor series, and the Exact Interactive Alogrithm are applied.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.12
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• pp.1112-1115
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• 2016

Global Positioning System(GPS) is a useful system used in both civilian and military applications. However, the signal of GPS is susceptible to jamming attacks due to low receive sensitivity, since the signals come from the satellite located at over 20,000 km above the earth. In this paper, we have conducted a preceding research on a non-Foster matching circuit that efficiently matches an electrically ultra-small GPS antenna. Electrically Small Antennas(ESAs) are inefficient radiators and are difficult to match in wideband due to extremely high quality factor. In order to match small GPS antenna in wideband, a non-Foster matching circuit for a small GPS antenna was designed. A negative impedance converter circuit consisting of Linvill's cross-coupled pair transistors was fabricated and its stability was verified by the time-domain stability analysis. In addition, anechoic chamber measurements show that the non-Foster matching circuit for small GPS antenna can lead bore-sight gain improvement by more than 17 dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1619-1625
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• 2017

Civil global navigation satellite system (GNSS) does not meet user performance requirements for specific PNT (Positioning, Navigation, and Time) applications. Therefore, various differential systems are used to augment GNSS for improving positioning accuracy and integrity. The MTSAT satellite augmentation system (MSAS) is the Japanese satellite based augmentation system. This paper is for analyzing the characteristics of Japanese MSAS in Korean peninsula. First of all, it was done for analyzing not only DGNSS navigation signal but also the navigation parameter through simulation and experimental tests. As a result of data analyses, the sufficient navigation satellites to determine 3-D position based on DGNSS are simultaneously available at MSAS monitering station and the southern region of Korean peninsula. It was verified that the carrier to noise signals are stable to maintain the reliable 3-D position and that the level of 2m (2drms) accuracy is very similar to the ordinary worldwide DGNSS as well.

• Journal of Advanced Navigation Technology
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• v.22 no.2
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• pp.96-104
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• 2018

NOTAM is an announcement that is distributed to flight attendants with status information related to aviation. ICAO, the International Civilian Aviation Organization, recommends that a NOTAM service be provided for the SBAS service in order to use the SBAS signal-based access procedure. To comply with ICAO recommendation, KASS must provide NOTAM service to all aircraft landing using SBAS signal in order to provide APV-I SoL service. Therefore, it is necessary to develop KASS NOTAM system to provide KASS NOTAM service. In this paper, we analyzed the regulations related to NOTAM in Korea and abroad and analyzed the present state of NOTAM service in Korea. Based on this, we propose a method of providing KASS NOTAM service. We analyzed the NOTAM system of WAAS in the US and EGNOS in Europe and analyzed the main functional requirements of the KASS NOTAM system.

• Journal of Life Science
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• v.28 no.9
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• pp.999-1006
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• 2018

Obesity is epidemic worldwide and has reportedly been linked to the progression of several metabolic and cardiovascular diseases. The natural products are decreasing the side effects of medicines used for obesity and also have health benefits dut to their numerous bioactive compounds. In this context, Artemisia scoparia is a widespread plant that has been suggested as possessing various types of bioactivity. In this study, the crude extract from A. scoparia (ASE) was tested for its ability to suppress adipogenesis in mouse 3T3-L1 pre-adipocytes. The molecular pathway by which ASE affects differentiation of 3T3-L1 cells was also investigated. The introduction of ASE to differentiating 3T3-L1 pre-adipocytes resulted in suppressed adipogenesis, as confirmed by decreased intracellular lipid accumulation. The differentiating cells treated with 10 and $100{\mu}g/ml$ of ASE showed 21.9 and 29.0% less lipid accumulation, respectively, than untreated adipocytes. In addition, the results indicated that ASE treatment lowered the expression of the adipogenesis-related factors $PPAR{\gamma}$, $C/EBP{\alpha}$, and SREBP-1c. Furthermore, treating with ASE notably decreased levels of phosphorylated p38, ERK, and JNK in 3T3-L1 adipocytes. These results indicate that ASE exhibits significant anti-adipogenesis activity by downregulating the MAPK and $PPAR{\gamma}$ pathways during the differentiation of 3T3-L1 pre-adipocytes. Therefore, A. scoparia may be a potential source of natural products against obesity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.267-275
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• 2010

Recently, the implementation & modern policy for Global Navigation Satellite System have actively been performed by USA, RUSSIA, EU & CHINA. Therefore 100+ navigation satellites will be in orbit by 2015, and the user of military and civil will benefit from the use of a total constellation of 100+ satellites. It means that the deepest dependence to GPS would be declined. In the paper, the latest technology development & implementation policy of GNSS have been analyzed. Specially, we focused on circumstance change of GNSS & application of navigation technology for modem weapon system. Finally, the application strategy of the integrated GNSS is suggested for military and civil as well.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.7
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• pp.674-679
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• 2008

In this paper, we introduce a new design approach for self-sustained resonant accelerometer, that takes advantage of the automatic gain control (AGC) loop to achieve a stabilized oscillation dynamics. Fundamental idea of this accelerometer is to maintain uniform amplitude of oscillation under input accelerations. Through system modeling and loop transformation considering the envelope of oscillation, the controller is designed to maintain uniform amplitude in oscillation under dynamic input acceleration. The simulation results demonstrate the feasibility of the proposed accelerometer design, which is applicable to control grade inertial measurement system in industrial and civil application fields.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.332-333
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• 2022

Recently, SpaceX, private enterprise dealing in space development company, has reported a plan for launching of 42,000 low earth orbit satellites until 2031 through Starlink Business, and launched 900 satellites until now. Concretely, it plans tp operate Ku/Ka band satellite, and launch 7,518 of V band satellites for broadband communication. Therefore, we can utilize wireless communication in an ocean, and various solutions through the low earth orbit satellites. This paper deals in a realization of wireless control system employing FPGA (Field Programmable Gate Array) for vessel applications.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.390-391
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• 2022

Recently, SpaceX, private enterprise dealing in space development company, has reported a plan for launching of low earth orbit satellites via Starlink Business, and launched 900 satellites until now. Concretely, it plans tp operate Ku/Ka band satellite, and launch 7,518 of V band satellites for broadband communication. Therefore, wireless communication service for ship will be provided, and various solutions will be offered through the low earth orbit satellites. In this work, we investigated RF characteristics of coplanar waveguide employing periodic 3D coupling structures, and examined its potential for a development of marine radio communication FISoC (fully-integrated system on chip) semiconductor device.