Research on Pilot Decision Model for the Fast-Time Simulation of UAS Operation
박승현 Seung-hyun Park , 이현웅 Hyeonwoong Lee , 이학태 Hak-tae Lee
25(1) 1-7, 2021
박승현 Seung-hyun Park , 이현웅 Hyeonwoong Lee , 이학태 Hak-tae Lee
DOI: JANT Vol.25(No.1) 1-7, 2021
Detect and avoid (DAA) system, which is essential for the operation of UAS, detects intruding aircraft and offers the ranges of turn and climb/descent maneuver that are required to avoid the intruder. This paper uses detect and avoid alerting logic for unmanned systems (DAIDALUS) developed at NASA as a DAA algorithm. Since DAIDALUS offers ranges of avoidance maneuvers, the actual avoidance maneuver must be decided by the UAS pilot as well as the timing and method of returning to the original route. It can be readily used in real-time human-in-the-loop (HiTL) simulations where a human pilot is making the decision, but a pilot decision model is required in fast-time simulations that proceed without human pilot intervention. This paper proposes a pilot decision model that maneuvers the aircraft based on the DAIDALUS avoidance maneuver range. A series of tests were conducted using test vectors from radio technical commission for aeronautics (RTCA) minimum operational performance standards (MOPS). The alert levels differed by the types of encounters, but loss of well clear (LoWC) was avoided. This model will be useful in fast-time simulation of high-volume traffic involving UAS.
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Selection and Evaluation of Vertiports of Urban Air Mobility (UAM) in the Seoul Metropolitan Area using the K-means Algorithm
정준영 Jun-young Jeong , 황호연 Ho-yon Hwang
25(1) 8-16, 2021
정준영 Jun-young Jeong , 황호연 Ho-yon Hwang
DOI: JANT Vol.25(No.1) 8-16, 2021
In this paper, locations of vertiports were selected and evaluated to operate urban air mobility (UAM) in the Seoul metropolitan area. Demand data were analyzed using the data from the survey of commuting population and were marked on a map using MATLAB. To cluster the data, the K-means algorithm function built in MATLAB was used to identify the center of the cluster to as the location of vertiports, and using the silhouette technique, the accuracy and reliability of the clustering were evaluated. The locations of the selected vertiports were also identified using satellite maps to ensure that the locations of the selected vertiports were suitable for the actual vertiport location, and, if the location was not appropriate, final vertiports were selected through the repositioning process.
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Aerodynamic Analysis, Required Power and Weight Estimation of a Compound (Tilt rotor + Lift + Cruise) Type eVTOL for Urban Air Mobility using Reverse Engineering Techniques
김동희 Dong-hee Kim , 이준희 Joon-hee Lee , 황호연 Ho-yon Hwang
25(1) 17-28, 2021
김동희 Dong-hee Kim , 이준희 Joon-hee Lee , 황호연 Ho-yon Hwang
DOI: JANT Vol.25(No.1) 17-28, 2021
Recently, eVTOL, the next-generation of eco-friendly transportation, has been in the spotlight due to global warming along with traffic jams in large cities of many countries. This study benchmark the external features of Hyundai Motors S-A1, a compound eVTOL combined fixed and tilt rotors among many types of eVTOLs, to create the basic configuration using reverse design techniques. Basic configurations were created using CATIA and aerodynamic analyses were performed using the aircraft design and aerodynamic analysis programs, OpenVSP, XFLR5, and the aircraft wetted area, drag, and lift were calculated after selecting the airfoil, incidence angle, and dihedral and anhedral angles through trade study. Also, required powers were estimated for completing the given mission profile and components weight and the total weight were predicted using the estimation formula and data survey.
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Preliminary Conceptual Design of a Multicopter Type eVTOL using Reverse Engineering Techniques for Urban Air Mobility
최원석 Won-seok Choi , 이동규 Dong-kyu Yi , 황호연 Ho-yon Hwang
25(1) 29-39, 2021
최원석 Won-seok Choi , 이동규 Dong-kyu Yi , 황호연 Ho-yon Hwang
DOI: JANT Vol.25(No.1) 29-39, 2021
As a means of solving traffic congestion in the downtown of large city, the interest in urban air mobility (UAM) using electric vertical take-off landing personal aerial vehicle (eVTOL PAV) is increasing. eVTOL configurations that will be used for UAM are classified by lift-and-cruise, tilt rotors, tilt-wings, tilted-ducted fans, multicopters, depending on propulsion types. This study tries to perform preliminary conceptual design for a given mission profile using reverse engineering techniques by taking the multicopter type Airbus’s CityAirbus as a basic model. Wetted area, lift to drag ratio, drag coefficients were calculated using the OpenVSP which is an aerodynamic analysis software. The power required for each mission section of CityAirbus were calculated, and the corresponding battery and motor were selected. Also, total weight was predicted by estimating component weights of eVTOL.
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Design Requirement Analysis and Configuration Proposal of a Vertiport for Domestic Applications of the Urban Air Mobility
안병선 Byeong-seon Ahn , 황호연 Ho-yon Hwang
25(1) 40-51, 2021
안병선 Byeong-seon Ahn , 황호연 Ho-yon Hwang
DOI: JANT Vol.25(No.1) 40-51, 2021
In this paper, the design requirements was produced by analyzing domestic and foreign regulations of the vertical takeoff and landing site required to operate the urban air mobility (UAM) system in Korea and the size of the take-off and landing pads were defined, and the configuration of vertiport was proposed. First, for the metropolitan area with high population density, pilot locations of the vertical take-off and landing site were selected based on the demonstration routes suggested by the Ministry of Land, Infrastructure and Transport and analyzed the characteristics of each location and determined the number of possible installations of vertiport by measuring each site. After that, variables necessary for the operation of the vertical takeoff and landing area were set, and the hourly, daily, monthly aircraft operating cycle, the number of acceptable people, and efficiency were calculated according to the number of simultaneous operation and the number of stand. Finally, using CATIA, the configurations of the virtual vertiport was created by applying the design requirements.
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Unstable Approach Mitigation Based on Flight Data Analysis
김현덕 Kim Hyeon Deok
25(1) 52-59, 2021
김현덕 Kim Hyeon Deok
DOI: JANT Vol.25(No.1) 52-59, 2021
According to the International Air Transport Association (IATA), 61% of the accidents occurred during the approach and landing phase of the flight, with 16% of the accidents caused by unstable access of the commercial aircraft. It was identified that the pilot's unstable approach and poor manipulation of correction led to accidents by continuing the excessive approach without go-around manuever. The causes of unstable access may vary, including airport approach procedures, pilot error, misplanning, workload, ATC (Air Traffic Contol) congestion, etc. In this study, we use the flight data analysis system to select domestic case airports and aircraft type where unstable approach events occur repeatedly. Through flight data analysis, including main events, airport approach procedures, pilot operations, as well as various environmental factors such as weather and geographical conditions at the airport. It aims to identify and eliminate the tendency of unstable approach events and the causes and risks of them to derive implications for mitigating unstable approach events and for developing navigation safety measures.
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A Precision Positioning Method of Drone Last-mile Delivery Technology in Urban Areas
김규석 Kyuseok Kim
25(1) 60-67, 2021
김규석 Kyuseok Kim
DOI: JANT Vol.25(No.1) 60-67, 2021
Countries around the world, including the U.S. are actively researching to commercialize the logistics services using drones. In Korea, telecommunications companies as well as logistics companies are researching and developing the logistics services using drones. However, there’s an environmental difference for last-mile delivery between the U.S. and Korea. In Korea, more than 77% of the population lives in apartments and the population density is the 4th highest in the world. Accordingly, in terms of the logistics services using drones, it is necessary to research it with the Korean suitable environment. In this paper, a precision positioning method of drone last-mile delivery in urban areas using short-range wireless communication and barometer is proposed. The experiment results show that the proposed method can detect a window within 2.5 meters. It is expected that the proposed method will help improve the logistics services using drones in urban areas.
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Design of a Compact GPS/MEMS IMU Integrated Navigation Receiver Module for High Dynamic Environment
정구용 Koo-yong Jeong , 박대영 Dae-young Park , 김성민 Seong-min Kim , 이종혁 Jong-hyuk Lee
25(1) 68-77, 2021
정구용 Koo-yong Jeong , 박대영 Dae-young Park , 김성민 Seong-min Kim , 이종혁 Jong-hyuk Lee
DOI: JANT Vol.25(No.1) 68-77, 2021
In this paper, a GPS/MEMS IMU integrated navigation receiver module capable of operating in a high dynamic environment is designed and fabricated, and the results is confirmed. The designed module is composed of RF receiver unit, inertial measurement unit, signal processing unit, correlator, and navigation S/W. The RF receiver performs the functions of low noise amplification, frequency conversion, filtering, and automatic gain control. The inertial measurement unit collects measurement data from a MEMS class IMU applied with a 3-axis gyroscope, accelerometer, and geomagnetic sensor. In addition, it provides an interface to transmit to the navigation S/W. The signal processing unit and the correlator is implemented with FPGA logic to perform filtering and corrrelation value calculation. Navigation S/W is implemented using the internal CPU of the FPGA. The size of the manufactured module is 95.0x85.0x.12.5mm, the weight is 110g, and the navigation accuracy performance within the specification is confirmed in an environment of 1200m/s and acceleration of 10g.
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Establishment of Flight Inspection Evaluation Items and Optimal Design of SBAS Performance Test Measurement Equipment by Analyzing Evaluation Items and Essential Components of Korean SBAS
김영빈 Young-bin Kim , 홍교영 Gyo-young Hong
25(1) 78-83, 2021
김영빈 Young-bin Kim , 홍교영 Gyo-young Hong
DOI: JANT Vol.25(No.1) 78-83, 2021
Due to rapidly increasing air traffic congestion and airspace restrictions, the International Civil Aviation Organization (ICAO) is urging all aircraft to use SBAS by 2025, in order to implement Performance-based navigation to increase airspace capacity. In line with this, research and development of Korean-style SBAS, which reflects the characteristics of Korea's airspace environment, continues in Korea. Since there is no flight inspection procedure for performance testing and verification of SBAS in Korea yet, this paper analyzes FAA, ICAO Regulations, and laws enacted by the Ministry of Land, Infrastructure and Transport to derive essential evaluations and parameters of Korean SBAS, and presents the optimal design using RTK-DGPS as a position fixing system.
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Asymmetric-type Dispersion-managed Link with Optical Phase Conjugation
이성렬 Seong-real Lee
25(1) 84-89, 2021
이성렬 Seong-real Lee
DOI: JANT Vol.25(No.1) 84-89, 2021
The alternative method for symmetric configuration in optical link consisted of dispersion management and optical phase conjugation for compensating of the distorted optical signals due to chromatic dispersion and nonlinear effects of standard single mode fiber is proposed. The symmetric configuration means number of fiber spans, dispersion distribution in former half section and latter half section, etc should be symmetrical about optical phase conjugator. In dispersion-managed proposed in this research, optical phase conjugator is located after former half section consisted of 6 fiber spans and before latter half section of 14 fiber spans, and the averaged residual dispersion per span (RDPS) of each half section are consistence. The compensation effects of the distorted signals in the proposed link is analyzed by comparing with the results obtained in dispersion-managed link with the unequally averaged RDPS of each half section. From the simulation results, it is confirmed that RDPS deviation between adjacent fiber span has a grater effect on the compensation than the equivalent of the averaged RDPS.
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Design of High-Sensitivity Compact Resonator using Interdigital-Capacitor Structure for Chipless RFID Applications
여준호 Junho Yeo , 이종익 Jong-ig Lee
25(1) 90-95, 2021
여준호 Junho Yeo , 이종익 Jong-ig Lee
DOI: JANT Vol.25(No.1) 90-95, 2021
In this paper, the design method for a high-sensitivity compact resonator for chipless RFID tags is proposed. Proposed high-sensitivity compact resonator uses an interdigital-capacitor structure instead of a capacitor-shaped strip structure in a conventional ELC resonator. The length of the electrode plate of the IDC structure is longer than that of the conventional capacitor-shaped structure, resulting in a larger equivalent capacitance of the resonator. This can lower the resonant peak frequency of the RCS characteristic. Two resonators with the same length of the square loop and the width of the strip are fabricated on an RF-301 substrate with a thickness of 0.8 mm. The experiment results show that the resonant peak frequency and value of the bistatic RCS for the ELC resonator were 4.305 GHz and -30.39 dBsm, whereas those of the proposed IDC resonator were 3.295 GHz and -36.91 dBsm. Therefore, the size of the resonator is reduced by 23.5% based on the measured resonant peak frequency of the RCS characteristic.
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Machine Learning-based Stroke Risk Prediction using Public Big Data
정선우 Sunwoo Jeong , 이민지 Minji Lee , 유선용 Sunyong Yoo
25(1) 96-101, 2021
정선우 Sunwoo Jeong , 이민지 Minji Lee , 유선용 Sunyong Yoo
DOI: JANT Vol.25(No.1) 96-101, 2021
This paper presents a machine learning model that predicts stroke risks in atrial fibrillation patients using public big data. As the training data, 68 independent variables including demographic, medical history, health examination were collected from the Korean National Health Insurance Service. To predict stroke incidence in patients with atrial fibrillation, we applied deep neural network. We firstly verify the performance of conventional statistical models (CHADS2, CHA2DS2-VASc). Then we compared proposed model with the statistical models for various hyperparameters. Accuracy and area under the receiver operating characteristic (AUROC) were mainly used as indicators for performance evaluation. As a result, the model using batch normalization showed the highest performance, which recorded better performance than the statistical model.
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Research and Implementation of An Experiencing Fairy Tale Content for Young Inpatients using Augmented Reality
조민화 Min-hwa Jo , 정준영 Jun-young Jung , 최규리 Kyu-ri Choi , 조세홍 Sae-hong Cho
25(1) 102-107, 2021
조민화 Min-hwa Jo , 정준영 Jun-young Jung , 최규리 Kyu-ri Choi , 조세홍 Sae-hong Cho
DOI: JANT Vol.25(No.1) 102-107, 2021
In the case of long-term hospitalization for young patients, ‘Hospital Schools’ are operated to pursue school classes and to develop social and emotional abilities for them. However, face-to-face classes at hospital schools have been completely prohibited, and the untact or limited contact environment has been strengthened even for young patients due to the COVID-19 in recent years. Augmented Reality(AR) technology enables the development of experiential content with virtual environments, objects and characters similar to real life. The developed contents should revitalize the imagination of young patients living only in hospitals and allow them to experience, not only acquiring knowledge, but also improving interpersonal skills and sociality. This study is intended to provide diverse adventures and in-depth choice experiences to young patients who are struggling in an environment of untact and limited contact by creating experiential fairy tale contents using AR technology. In addition, long-term hospitalized children will be able to cultivate the will to overcome illness with positive emotions through the augmented reality experience fairy tale content studied and implemented in this study.
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Research and Development of Virtual School Life Experiencing Contents Using Virtual Reality Technology in the Untact Era
심재혁 Jae-hyeok Sim , 조세홍 Sae-hong Cho
25(1) 108-114, 2021
심재혁 Jae-hyeok Sim , 조세홍 Sae-hong Cho
DOI: JANT Vol.25(No.1) 108-114, 2021
In recent years, human is experiencing an ‘untact’ era that has not been existed before. A remarkable features of an untact era is a limited or no interaction with other people and things in a daily life. In order to overcome this special situation, diverse state-of-the-art technologies like ICT technology are being used to give the effect of face-to-face and contact. In particular, Virtual Reality technology allows users to actively interact with virtual environments, objects, and other people, thereby providing effects that are as similar as possible to experience in real life. School freshmen are also experiencing various inconveniences because they are not experiencing the environment or academic management of newly admitted schools in the untact era. This research is a study and implementation of ‘Virtual School Life Experience Content’ which provides new students to tour campus, to utilize the school buildings facilities, to experience of academic schedules including course registration, and to participate in school events in an environment that is as close as possible to the real campus. Freshmen will be able to easily adapt to a new school through the implemented VR content.
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Deep Learning Based Pine Nut Detection in UAV Aerial Video
김규민 Gyu-min Kim , 박성준 Sung-jun Park , 황승준 Seung-jun Hwang , 김희영 Hee Yeong Kim , 백중환 Joong-hwan Baek
25(1) 115-123, 2021
김규민 Gyu-min Kim , 박성준 Sung-jun Park , 황승준 Seung-jun Hwang , 김희영 Hee Yeong Kim , 백중환 Joong-hwan Baek
DOI: JANT Vol.25(No.1) 115-123, 2021
Pine nuts are Korea's representative nut forest products and profitable crops. However, pine nuts are harvested by climbing the trees themselves, thus the risk is high. In order to solve this problem, it is necessary to harvest pine nuts using a robot or an unmanned aerial vehicle(UAV). In this paper, we propose a deep learning based detection method for harvesting pine nut in UAV aerial images. For this, a video was recorded in a real pine forest using UAV, and a data augmentation technique was used to supplement a small number of data. As the data for 3D detection, Unity3D was used to model the virtual pine nut and the virtual environment, and the labeling was acquired using the 3D transformation method of the coordinate system. Deep learning algorithms for detection of pine nuts distribution area and 2D and 3D detection of pine nuts objects were used DeepLabV3+, YOLOv4, and CenterNet, respectively. As a result of the experiment, the detection rate of pine nuts distribution area was 82.15%, the 2D detection rate was 86.93%, and the 3D detection rate was 59.45%.
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