Noise Analysis for the Operation of the eVTOL PAV using AEDT (Aviation Environmental Design Tool)
윤주열 Ju-yeol Yun , 이봉술 Bong-sul Lee , 황호연 Ho-yon Hwang
23(4) 265-272, 2019
윤주열 Ju-yeol Yun , 이봉술 Bong-sul Lee , 황호연 Ho-yon Hwang
DOI: JANT Vol.23(No.4) 265-272, 2019
In this paper, we selected commuting scenarios in the most congested metropolitan area in Korea, and conducted noise analysis during personal air vehicle (PAV) operation using aviation environmental design tool (AEDT) software which was developed by Federal Aviation Administration (FAA). Noise is the second important factor after safety in order to operate PAVs through concepts such as ODM (on-demand mobility) introduced by National Aeronautics and Space Administration (NASA). Noise analysis were performed by modeling low-noise ePAVs as commercial helicopters and predicted residential suitability in order to resolve problems in which accurate NPD (noise power distance) data from PAVs were not released. The application of noise reduction technology such as electric propulsion has significantly reduced noise exposure levels and has reached the conclusion that commuting with PAVs is feasible without noise problems in the metropolitan area.
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Improvement of Strain Detection Accuracy of Aircraft FBG Sensors Using Stationary Wavelet Transform
손영준 Yeong-jun Son , 신현성 Hyun-sung Shin , 홍교영 Gyo-young Hong
23(4) 273-280, 2019
손영준 Yeong-jun Son , 신현성 Hyun-sung Shin , 홍교영 Gyo-young Hong
DOI: JANT Vol.23(No.4) 273-280, 2019
There are many studies that use structure health monitoring to reduce maintenance costs for aircraft and to increase aircraft utilization. Many studies on FBG sensors are also being conducted. However, if the FBG sensor is installed inside the composite, voids will occur between the layers of the composite, resulting in signal split problem. In addition, the FBG sensor is not affected by electromagnetic waves, but will produce electromagnetic noise caused by electronic equipment during post-processing. In this paper, to reduce the error caused by these noises, the stationary wavelet transform, which has the characteristics of movement immutability and is efficient in nonlinear signal analysis, is presented. And in the above situation, we found that noise rejection performance of stationary wavelet transform was better compared with the wavelet packet transform.
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A Study on the Guidelines for the Development of Domestic Flight Test Operation Manual
김무근 Mu-geun Kim , 백승돈 Seung-don Baek , 송찬용 Chan-yong Song , 안대희 Dae-whee Ahn , 한정호 Jeongho Han , 유병선 Beong-seon Yoo , 강자영 Ja-young Kang
23(4) 281-288, 2019
김무근 Mu-geun Kim , 백승돈 Seung-don Baek , 송찬용 Chan-yong Song , 안대희 Dae-whee Ahn , 한정호 Jeongho Han , 유병선 Beong-seon Yoo , 강자영 Ja-young Kang
DOI: JANT Vol.23(No.4) 281-288, 2019
A Flight test is an important process that must be performed to maintain airworthiness in the aircraft lifecycle, including aircraft development and certification. Flight test can be conducted for the purpose of demonstrating or verifying compliance with the applicable standard. Results of the flight test air accident analysis confirm that it is caused by a combination of various factors as well as aircraft. The International Civil Aviation Organization recommends the establishment and implementation of a safety management system to prevent aircraft accidents, but it does not reflect the specificity of the flight test. As such, advanced countries are providing separate criteria to assist stakeholder in conducting flight test safety management. This study investigates and analyzes relevant regulations of advanced countries, in accordance with the construction of a national flight performance test site in Korea, and proposes government-level guidelines to help stakeholders develop their flight test operation manuals. The guidelines discuss topics such as organizational composition, safety and risk management, flight operation, personnel management, and administrative issues.
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Design for Back-up of Ship’s Navigation System using UAV in Radio Frequency Interference Environment
박슬기 Sul Gee Park , 손표웅 Pyo-woong Son
23(4) 289-295, 2019
박슬기 Sul Gee Park , 손표웅 Pyo-woong Son
DOI: JANT Vol.23(No.4) 289-295, 2019
Maritime back-up navigation system in port approach requires a horizontal accuracy of 10 meters in IALA (International Association of Lighthouse Authorities) recommendations. eLoran which is a best back-up navigation system that satisfies accuracy requirement has poor navigation performance depending signal environments. Especially, noise caused by multipath and electronic devices around eLoran antenna affects navigation performance. In this paper, Ship based Navigation Back-up system using UAV on Interference is designed to satisfy horizontal accuracy requirement. To improve the eLoran signal environment, UAVs are equipped with camera, IMU sensor and eLoran antenna and receivers. This proposed system is designed to receive eLoran signal through UAV-based receiver and control UAV’s position and attitude within Landmark around area. The ship-based positioning using eLoran signal, vision and attitude information received from UAV satisfy resilient and robust navigation requirements.
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Big Data Analytics for Countermeasure System Against GPS Jamming
최영동 Young-dong Choi , 한경석 Kyeong-seok Han
23(4) 296-301, 2019
최영동 Young-dong Choi , 한경석 Kyeong-seok Han
DOI: JANT Vol.23(No.4) 296-301, 2019
Artificial intelligence is closely linked to our real lives, leading innovation in various fields. Especially, as a means of transportation possessing artificial intelligence, autonomous unmanned vehicles are actively researched and are expected to be put into practical use soon. Autonomous cars and autonomous unmanned aerial vehicles are required to equip accurate navigation system so that they can find out their present position and move to their destination. At present, the navigation of transportation that we operate is mostly dependent on GPS. However, GPS is vulnerable to external intereference. In fact, since 2010, North Korea has jammed GPS several times, causing serious disruptions to mobile communications and aircraft operations. Therefore, in order to ensure safety in the operation of the autonomous unmanned vehicles and to prevent serious accidents caused by the intereference, rapid situation judgment and countermeasure are required. In this paper, based on big data and machine learning technology, we propose a countermeasure system for GPS interference that supports decision making by applying John Boyd 's OODA loop cycle (detection - direction setting - determination - action).
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Dynamic Routing and Priority-based Data Transmission Schemes in Avionic Ethernet for Improving Network QoS
이원진 Won Jin Lee , 김용민 Yong Min Kim
23(4) 302-308, 2019
이원진 Won Jin Lee , 김용민 Yong Min Kim
DOI: JANT Vol.23(No.4) 302-308, 2019
Aircraft data network (ADN) is a data networking for signal transmission among avionic systems in aircraft, and it mostly has been applied MIL-STD-1553B that guarantees high reliability considering its application environments. However, commercial Ethernet has been widely applied for ADN recently, and its range of applications have increased. Ethernet provides high speed of data transmission, however, it could not guarantee quality of service (QoS) so high as MIL-STD-1553B. In this paper, we propose dynamic routing and priority based data transmission schemes in order to improve the QoS of legacy Ethernet. Our propose schemes can be applied to Ethernet switch, and it is able to manage network traffic efficiently, and reduce the time for data transmission. We analyze the packet transmission time for both legacy and proposed schemes in Ethernet environments using simulation, and we show that our proposed scheme can reduce the time for data transmission compare to legacy spanning tree protocol.
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Unequal Multi-Section Power Divider using CPW and Offset Coupled Transmission Lines
최종운 Jong-un Choi , 윤영철 Young-chul Yoon , 성규제 Gyu-je Sung , 김영 Young Kim
23(4) 309-315, 2019
최종운 Jong-un Choi , 윤영철 Young-chul Yoon , 성규제 Gyu-je Sung , 김영 Young Kim
DOI: JANT Vol.23(No.4) 309-315, 2019
This paper proposes an implementation of unequal power divider with 1:3 and 1:4 splitting ratio in multi-section structure using CPW and offset coupled transmission line. The power divider consists of a multi-section transmission line and a circuit with parallel capacitors and resistors. A multi-section transmission line was implemented by decomposing a λ /4 single transmission line terminated by an arbitrary impedance and converging it with a multi-section transmission line shorter than 90o electrical length, and RC parallel circuits were connected between transmission lines to obtain reflection coefficient of output port and isolation characteristics between the output port. In this way, it was confirmed that the transmission lines at the unequal power divider designed at 2 GHz were shorter than λ/4 and implemented at least 27% less than the conventional ones, and that the broadband characteristics could be obtained.
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Development of High Precision Impedance Measurement Systems in Specific Ranges Using a Microprocessor
유재춘 Jae-chun Ryu , 이명의 Myung-eui Lee
23(4) 316-321, 2019
유재춘 Jae-chun Ryu , 이명의 Myung-eui Lee
DOI: JANT Vol.23(No.4) 316-321, 2019
In this paper, by applying the constant current principle we develop an impedance measurement system which can measure the high precision impedance of various electric materials by using microprocessor. This measurement system board has an interface device for acquiring digital data from an external device including an impedance measuring device, and system software is also developed by a firmware program executed on such an embedded board. It can measure the high precision impedance of a specific band with 1/32768 precision by using 15-bit ADC(analog to digital converter) and calculate it to the five digits to the right of the decimal point(fraction part). Data is transmitted through a USB interface of a general computer and a measuring device to manage digital data. An impedance measurement system equipped with a communication function capable of a more general and easy-to-use interface than other equipment is developed and verified.
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Cognitive User's Quality of Service Enhancement by using Spectrum Hole Grouping in Cellular Cognitive Radio Networks
이진이 Jin-yi Lee
23(4) 322-327, 2019
이진이 Jin-yi Lee
DOI: JANT Vol.23(No.4) 322-327, 2019
In this paper, we propose first a scheme of grouping spectrum holes that are created in the multiple channels of primary users, and then by using the scheme we enhance quality of service (QoS) of wideband cognitive radio users in cellular cognitive radio networks. In our scheme, spectrum holes created in each primary channel are predicted by Wiener prediction process, and then the predicted spectrum holes happened in the same time are grouped into a group. The wideband cognitive radio users explore the group of spectrum holes to improve their QoS. Simulation results show that their handoff calls dropping rate and initial calls blocking rate are significantly reduced in our scheme, compared to those in the single primary channel.
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Web Assembly System Architecture Model
박진태 Jin-tae Park , 문일영 Il-young Moon
23(4) 328-332, 2019
박진태 Jin-tae Park , 문일영 Il-young Moon
DOI: JANT Vol.23(No.4) 328-332, 2019
Advances in web technology have enabled technical convergence in various system environments to be carried out through the web interface. The Web can be categorized from the Web 1.0 to the 4.0, depending on its role, it has the characteristics of connects information, connects people, connects knowledge, and connects intelligence. In addition, various technological needs occurred through the mobile app during the 4th Industrial Revolution, and functions such as 3D, virtual reality, augmented reality, video/audio processing were enabled on the web, which was a simple means of providing information. Technical standards have been studied to support these period needs. In this paper, I would like to mention one of the Web assembly. We will explore ways to link and fuse Web assembly with existing web systems (or platforms) and analyze their technical implications through a variety of examples. In addition, we will conduct a study on the architecture that can fuse the existing javascript with the web assembly, and discuss the future direction of the study.
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