Analysis of the Maritime Communication Requirements in the e-Navigation Era
양규식 Gyul-sik Yang
21(5) 423-427, 2017
양규식 Gyul-sik Yang
DOI: JANT Vol.21(No.5) 423-427, 2017
The IMO approved e-navigation strategy implementation plan made e-navigation adoption visible. In addition, the schedule for the modernization of GMDSS by the ITU was confirmed at the 4th NCSR meeting. Accordingly, we will complement the existing communication system and provide the requirements for the new communication system to be introduced in the future, reflecting all the requirements for the communication system capable of supporting the e-navigation service. Although the communication method for supporting e-navigation service should be capable of providing IP-based data communication basically, it is impossible to provide internet service because of the narrow-band characteristic in the MF/HF frequency bands. In addition, as the existing GMDSS satellite communication service organization expands and new services are introduced, IP based data communication service will be possible, but service restriction resulting from expensive communication cost can be solved by introducing VSAT service.
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Analysis of Interference Effect on FS System from ESIM with Motion Characteristics
강영흥 Young-houng Kang , 오대섭 Dae-sub Oh
21(5) 428-434, 2017
강영흥 Young-houng Kang , 오대섭 Dae-sub Oh
DOI: JANT Vol.21(No.5) 428-434, 2017
In recent years, owing to the growing user demand for the two-way internet service based on the mobile global broadband communications, a new type of satellite terminal has been developed, known as ESIM(Earth Station in Motion). This service was required by Resolution 158(WRC-15) to study on the coexistence with the co-primary FS(Fixed Service) in 27.5-29.5 GHz as a FSS(Fixed Satellite Service) uplink. In this paper, the average received power on ESIM within -10 dB of beam width of FS and its outage probability was analyzed theoretically and also simulated to account for the azimuth angle with uniform distribution. From the results, it can be concluded that this theoretical analysis is very useful to analyze the interference from ESIM into FS based on the statistical and probabilistic method. Therefore, it is necessary to control the azimuth angle due to a moving terminal as well as the inclination angle of moving path, the operation hours, and the speed of ESIM to protect the co-primary FS.
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Development for Estimation Model of Runway Visual Range using Deep Neural Network
구성관 Sungkwan Ku , 홍석민 Seokmin Hong
21(5) 435-442, 2017
구성관 Sungkwan Ku , 홍석민 Seokmin Hong
DOI: JANT Vol.21(No.5) 435-442, 2017
The runway visual range affected by fog and so on is one of the important indicators to determine whether aircraft can take off and land at the airport or not. In the case of airports where transportation airplanes are operated, major weather forecasts including the runway visual range for local area have been released and provided to aviation workers for recognizing that. This paper proposes a runway visual range estimation model with a deep neural network applied recently to various fields such as image processing, speech recognition, natural language processing, etc. It is developed and implemented for estimating a runway visual range of local airport with a deep neural network. It utilizes the past actual weather observation data of the applied airfield for constituting the learning of the neural network. It can show comparatively the accurate estimation result when it compares the results with the existing observation data. The proposed model can be used to generate weather information on the airfield for which no other forecasting function is available.
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Consensus-based Autonomous Search Algorithm Applied for Swarm of UAVs
박국권 Kuk-kwon Park , 권호준 Ho-jun Kwon , 최은주 Eunju Choi , 유창경 Chang-kyung Ryoo
21(5) 443-449, 2017
박국권 Kuk-kwon Park , 권호준 Ho-jun Kwon , 최은주 Eunju Choi , 유창경 Chang-kyung Ryoo
DOI: JANT Vol.21(No.5) 443-449, 2017
Swarm of low-cost UAVs for search mission has benefit in the sense of rapid search compared to use of single high-end UAV. As the number of UAVs forming swarm increases, not only the time for the mission planning increases, but also the system to operate UAVs has excessive burden. This paper addresses a decentralized area search algorithm adequate for multiple UAVs which takes advantages of flexibility, robustness, and simplicity. To down the cost, it is assumed that each UAV has limited ability: close-communication, basic calculation, and limited memory. In close-communication, heath conditions and search information are shared. And collision avoidance and consensus of next search direction are then done. To increase weight on un-searched area and to provide overlapped search, the score function is introduced. Performance and operational characteristics of the proposed search algorithm and mission planning logic are verified via numerical simulations.
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Linear Quadratic Controller Design of Insect-Mimicking Flapping Micro Aerial Vehicle
김성근 Sungkeun Kim , 김인래 Inrae Kim , 김승균 Seungkeun Kim , 석진영 Jinyoung Suk
21(5) 450-458, 2017
김성근 Sungkeun Kim , 김인래 Inrae Kim , 김승균 Seungkeun Kim , 석진영 Jinyoung Suk
DOI: JANT Vol.21(No.5) 450-458, 2017
This paper presents dynamic modelling and simulation study on attitude/altitude control of an insect-mimicking flapping micro aerial vehicle during hovering. Mathematical modelling consists of three parts: simplified flapping kinematics, flapping-wing aerodynamics, and six degree of freedom dynamics. Attitude stabilization is accomplished through linear quadratic regulator based on the linearized model of the time-varying nonlinear system, and altitude control is designed in the outer loop using PID control. The performance of the proposed controller is verified through numerical simulation where attitude stabilization and altitude control is done for hovering. In addition, it is confirmed that the attitude channel by periodic control is marginally stable against periodic pitching moment caused by flapping.
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Design of Lightning Induced Transient Protection Circuit for Avionics Equipment Considering Parasitic Inductance
심용기 Yong-gi Sim , 조성진 Seong-jin Cho , 김성훈 Sung-hun Kim , 박준현 Jun-hyun Park , 한종표 Jong-pyo Han
21(5) 459-465, 2017
심용기 Yong-gi Sim , 조성진 Seong-jin Cho , 김성훈 Sung-hun Kim , 박준현 Jun-hyun Park , 한종표 Jong-pyo Han
DOI: JANT Vol.21(No.5) 459-465, 2017
In this paper, we introduce the design consideration of the lightning induced transient protection circuit for the indirect lightning strike on the avionics equipment. The lightning induced surge voltage, which is so-called as indirect effects of lightning, may cause a functional failure or physical damage to the electrical and electronic equipment of aircraft. In order to protect the electrical and electronic equipment of aircraft from the indirect effects of lightning, we should analyze the effect of lightning strike on aircraft and consider applying protection design for each avionics device. However, lightning induced transient protection circuits can have unintended consequences because parasitic inductance elements are exist in PCB and TVS diodes. In this paper, we introduce the design method of the protection circuit considering the parasitic inductance of the protection circuit. In addition, we show the result of verification test performed to validate the protection circuits for indirect effects of lightning.
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A Design of Low Profile Ku Band Parabolic Antenna using Elliptical Reflector Shape
류다운 Daun Ryu , 이경순 Kyung-soon Lee , 박대길 Dae-kil Park , 구경헌 Kyung Heon Koo
21(5) 466-471, 2017
류다운 Daun Ryu , 이경순 Kyung-soon Lee , 박대길 Dae-kil Park , 구경헌 Kyung Heon Koo
DOI: JANT Vol.21(No.5) 466-471, 2017
SOTM is a device for the satellite communication on the move. Many studies are conducted on microstrip, waveguide and array antenna for the low profile of the SOTM`s antenna. But those antennas have a problem that is difficult to adjust the polarization, and for that reason we have studied the parabolic antenna structure. The general form of parabolic reflector structure is circular, but we used cut-off shape reflector by cutting the upper and lower reflector for low profile antenna. Accordingly, this results in the decrease of reflector area which causes reduced gain and G/T ratio. In order to solve this problem, we have transformed and designed the sub reflector for improving the efficiency and gain of the cut- off shape parabolic antenna.
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A Algorithm on Optimizing Traffic Network by the Control of Traffic Signal Timing
안영필 Yeong- Pil An , 김동춘 Dong-choon Kim , 나승권 Seung-kwon Na
21(5) 472-478, 2017
안영필 Yeong- Pil An , 김동춘 Dong-choon Kim , 나승권 Seung-kwon Na
DOI: JANT Vol.21(No.5) 472-478, 2017
In this paper, we deals with optimizing traffic signal timing in grid networks by using a network topology design method. Optimizing traffic signal timing includes minimizing delay time delay between departure and destination by interlocking straight traffic signal in the minimum spanning tree(MST).
On the assumption that users of network abide by the paths provided in this paper, this paper shows optimizing traffic signal timing in grid networks. the paths provided in this paper is gathered by using Dijkstra algorithm used in computer networks.
The results indicate minimizing delay time of passing through the grid network and interlocking traffic signal in the grid network.
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A Positioning Accuracy Analysis in Korea by using NTCM-BC Ionosphere Model
김민규 Mingyu Kim , 명재욱 Jaewook Myung , 김정래 Jeongrae Kim
21(5) 479-485, 2017
김민규 Mingyu Kim , 명재욱 Jaewook Myung , 김정래 Jeongrae Kim
DOI: JANT Vol.21(No.5) 479-485, 2017
A Neustrelitz TEC model (NTCM) developed by Deutsches Zentrum fur Luft- und Raumfahrt (DLR) provides a better accuracy than the global positioning system (GPS) Klobuchar model for predicting ionospheric delay. The NTCM model accuracy is comparable to Galileo NeQuick model, and it has less computation time. The NTCM model uses F10.7 values as a parameter of solar activity function, while a NTCM-Broadcast (NTCM-BC) uses TEC values from a Klobuchar model. For this reason, a NTCM-BC model can be used for real-time ionosphere correction. In this paper, vertical ionospheric delay and GPS positioning errors in Korea by using a NTCM-BC ionosphere model from 2009 to 2014 are analyzed and compared with those of a Klobuchar model. In the 6-year statistics, the vertical ionospheric delay is reduced by 17.7 %, and horizontal and vertical positioning accuracies by the NTCM-BC model are improved by 25.6 % and 6.7 %, respectively, over the Klobuchar model.
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Acceleration for Removing Sea-fog using Graphic Processors and Parallel Processing
김영두 Young-doo Kim , 곽재민 Jae-min Kwak , 서영호 Young-ho Seo , 최현준 Hyun-jun Choi
21(5) 485-490, 2017
김영두 Young-doo Kim , 곽재민 Jae-min Kwak , 서영호 Young-ho Seo , 최현준 Hyun-jun Choi
DOI: JANT Vol.21(No.5) 485-490, 2017
In this paper, we propose a technique for high speed removal of sea-fog using a graphic processor. This technique uses a host processor(CPU) and several graphics processors(GPU) capable of parallel processing to remove sea-fog from the input image. In the process of removing sea-fog, the dark channel extraction, the maximum brightness channel extraction, and the calculation of the transmission are performed by the host processor, and the process of refining the transmission by applying the bidirectional filter is performed in parallel through the graphic processor. To verify the proposed parallel processing method, three NVIDIA GTX 1070 GPUs were used to construct the verification environment. As a result, it takes about 140ms when implemented with one graphics processor, and 26ms when implemented using OpenMP and multiple GPGPUs. The proposed a parallel processing algorithm based on the graphics processor unit can be used for safe navigation, port control and monitoring system.
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Implementation of the Traffic Control System based Low Cost Dual Modular Redundancy
이동우 Dong-woo Lee , 나종화 Jong-whoa Na , 김남선 Nam-sun Kim
21(5) 491-500, 2017
이동우 Dong-woo Lee , 나종화 Jong-whoa Na , 김남선 Nam-sun Kim
DOI: JANT Vol.21(No.5) 491-500, 2017
This paper investigates a low cost dual modular redundancy system based on heartbeat which can be applied to traffic control signal system. Failure of the traffic control signal system can cause traffic confusion and traffic accidents. Therefore safety and reliability of traffic control should be secured using fault tolerance technology. To do this, we configured a redundant board using the open source hardware and the heartbeat technique of Linux HA. The function of the traffic signal control system was verified and the fault recovery time was measured using fault injection test. As a result of the test, the fault recovery time was confirmed to be less than 9 seconds on average, confirming that the reliability target time is satisfied. Based on the results of this study, it is expected that it can be applied to fields requiring high reliability systems such as aviation, space, and nuclear power embedded systems.
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Development of a voltage-controlled output current source for zenor diode degradation analysis
김종호 Jong-ho Kim , 장홍기 Hong-ki Chang , 권영목 Young-mok Kwon , 최규식 Gyu-shik Che
21(5) 501-507, 2017
김종호 Jong-ho Kim , 장홍기 Hong-ki Chang , 권영목 Young-mok Kwon , 최규식 Gyu-shik Che
DOI: JANT Vol.21(No.5) 501-507, 2017
When zenor diode load current is necessary to be controlled by input voltage as a circuit load, existing voltage controlling method cannot be applied to it because the output current of zenor diode is changed due to breakdown voltage variations. We propose input voltage controlled output current source regardless of zenor breakdown voltage variation due to degradation resulted from severe current applied electronic component life test as a circuit load in this paper. We show breakdown voltage characteristics of this zenor diode circuit through simulation, applying adequate values for each component in order to verify the circuit composed of that method, and then show the result in which output current is controlled by input voltage. We confirmed the output current varies proportional to input voltage, and developed circuit shows a constant value independent of zenor diode breakdown voltage variations due to component degradations.
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Maintainability Improvement of Automatic Test Equipment for Aircraft
서민기 Min-gi Seo , 권기용 Ki-yong Kwon , 김성우 Seong-woo Kim , 이성우 Seong-woo Lee
21(5) 508-513, 2017
서민기 Min-gi Seo , 권기용 Ki-yong Kwon , 김성우 Seong-woo Kim , 이성우 Seong-woo Lee
DOI: JANT Vol.21(No.5) 508-513, 2017
Maintainability in engineering terms means ease of maintenance / management of the product. Aircraft automatic test equipment (ATE) is heavily influenced by the design changes of the unit under test(UUT) since the test procedure is developed according to the function / performance characteristics of the UUT. Moreover, if the integrated ATE is an environment that checks more than one UUT, it is not easy to maintain the ATE for the UUT design changes. Developers should be able to flexibly cope with the change of development staff by selecting an easy and clear development method to improve the maintainability of ATE. It is also necessary to limit the area affected by the UUT design change to a specific range to minimize the area to be modified. In this paper, we propose ATE development method which focuses on maintenance improvement based on the aircraft ATE development process.
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Comparison of Positioning Accuracy Using the Pseudorange from Android GPS Raw Measurements
김준성 Joonseong Gim , 박관동 Kwan-dong Park
21(5) 514-519, 2017
김준성 Joonseong Gim , 박관동 Kwan-dong Park
DOI: JANT Vol.21(No.5) 514-519, 2017
In this paper, the pseudorange-based GPS performance using the Android's raw measurements is compared with NMEA. In order to compare the performance between the two different implementations, we used Nexus 9 tablets and collected the raw measurements and NMEA data using the GNSS logger application provided by Google. To verify the performance of the final coordinates calculated, the VRS was used as the reference coordinate and compared with the NMEA results. The resulting horizontal, vertical, and 3D RMS errors of the pseudorange-based GPS using the Android’s raw measurements are 3.05, 3.82, and 4.97 m, respectively, which correspond to 32% horizontal, 65% vertical and 49% 3D performance improvement compared with NMEA.
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