Requirement Analysis of Efficiency, Reliability, Safety, Noise, Emission, Performance and Certification Necessary for the Application of Urban Air Mobility (UAM)
윤주열 Ju-yeol Yun , 황호연 Ho-yon Hwang
24(5) 329-342, 2020
윤주열 Ju-yeol Yun , 황호연 Ho-yon Hwang
DOI: JANT Vol.24(No.5) 329-342, 2020
In this paper, we analyzed the requirements for the application of UAM, a new concept to solve the traffic congestion in large cities. First , the current domestic and foreign status of research and development related to UAM was investigated and the pros and cons and the time required for each mission radius were analyzed for various configurations of aircraft being commercialized. In addition, in order to analyze the market acceptance of the UAM, the individual's consciousness and reliability requirements were identified and safety requirements were analyzed through accident rate data for each aircraft type. Because it operates in a densely populated urban area, requirement analyses on noise and exhaust, which are environmental factors that can affect the community were performed , and requirements related to aircraft performance, certification standards, and airworthiness standards of FAA and EASA were also analyzed.
|
Development of 3D-Map Software for Ship Hull in Underwater
오말근 Mal-geun Oh , 김홍렬 Hong-ryeol Kim , 홍성화 Sung-hwa Hong
24(5) 343-347, 2020
오말근 Mal-geun Oh , 김홍렬 Hong-ryeol Kim , 홍성화 Sung-hwa Hong
DOI: JANT Vol.24(No.5) 343-347, 2020
This paper presents the development of a software for tracking the location of objects in the water and for creating a three-dimensional hull map. The objective of this software, as a software for underwater hull cleaning robot, is to map the location of underwater hull cleaning robot and to locate the position of sensor by identifying the shaded area of acoustic communication. For the software designed for mapping the location of cleaning robot in the water, the height and intensity were applied as variables for underwater ultrasonic communication. The software for creating a three-dimensional hull was developed by OpenGL using scanned lines from a blueprint of a ship. This software can help identifying the location of underwater hull cleaning robot without actual visibility and can be used to maintain a stable communication status by locating the position of sensor by easily spotting the shaded area of acoustic communication caused by the curved area of the bottom of the ship.
|
Noise Priority Route Generation and Noise Analysis for the Operation of Urban Air Mobility Considering Population Distribution
소민준 Min-jun So , 황호연 Ho-yon Hwang
24(5) 348-357, 2020
소민준 Min-jun So , 황호연 Ho-yon Hwang
DOI: JANT Vol.24(No.5) 348-357, 2020
An important challenge in commercialization of eVTOL PAV is to reduce noise for urban air mobility (UAM) operation. Therefore, in this paper, noise priority routes were created to minimize the number of people affected by noise using aviation environmental design tool (AEDT) software and population distribution data for administrative districts, and noise analyses during operation were performed. Also, it was analyzed how much noise exposure could be reduced compared to the number of people affected by noise in the shortest route. Considering that the eVTOL PAV developers do not provide data, the analysis was conducted using a helicopter model. As a result, it was shown that the noise priority route that minimized the amount of noise exposure was more efficient than other routes.
|
Selection of Vertiport Location, Route Setting and Operating Time Analysis of Urban Air Mobility in Metropolitan Area
오재석 Jae-seok Oh , 황호연 Ho-yon Hwang
24(5) 358-367, 2020
오재석 Jae-seok Oh , 황호연 Ho-yon Hwang
DOI: JANT Vol.24(No.5) 358-367, 2020
With the increases of average commuting time of office workers in the Seoul metropolitan area and the cost of traffic congestion on roads, the need for new transportation is increasing and urban air mobility (UAM) is emerging as an alternative. Therefore, in this paper, the vertiport locations were selected and routes were established using population, traffic and commuting data of Seoul and Gyeonggi Province. Vector thrust type and multicopter type of eVTOL compatible for UAM were selected by analyzing the types of eVTOL and time required for selected routes was calculated. In addition, the time required when we utilize other transportations was compared with UAM. Finally, it was verified that the commuting time can be sharply reduced when we use UAM.
|
The Future of Aerospace Weapon Systems based on Aerospace Technology Modeling
조태환 Taehwan Cho , 최인수 Insoo Choi , 이성섭 Soungsub Lee
24(5) 368-373, 2020
조태환 Taehwan Cho , 최인수 Insoo Choi , 이성섭 Soungsub Lee
DOI: JANT Vol.24(No.5) 368-373, 2020
In order to systematically apply major technologies of the 4th Industrial Revolution to aerospace power development, an aerospace technology model is needed. The Propeller Model, which is an existing aerospace model, is a concept that operates a combination of altitude, speed, and distance, which are basic characteristics of aerospace. However, in the era of the 4th Industrial Revolution, a new model is needed because numerous technologies are used in convergence. In this paper, a jet engine model is proposed as a new aerospace technology model. Also, we propose a procedure for creating future aerospace weapon systems based on aerospace technology modeling, not on operational capability. The utilization of future battlefields and the study of the concept of advanced weapon systems in developed countries can create a new concept of weapon systems.
|
Real-time Calculation of Geoid Applicable to Embedded Systems
김현석 Hyun-seok Kim , 박찬식 Chan-sik Park
24(5) 374-381, 2020
김현석 Hyun-seok Kim , 박찬식 Chan-sik Park
DOI: JANT Vol.24(No.5) 374-381, 2020
In order to improve the vertical position accuracy, the advantages of GPS and barometric altimeter are combined and used, but in order to fuse the two sensors, the geoid altitude must be compensated. In this paper, we proposed a technique that can calculate geoid altitude in real time even in low-cost embedded systems applied to drones or autonomous vehicles. Since the reference EGM08 is determined by a polynomial of the 2160th order, real-time calculation is impossible in the embedded system. Therefore, by introducing a linear interpolation technique, the amount of calculation was increased, and the storage space was saved by 75% by using the integer geoid height as a grid point. The accuracy of the proposed technique was evaluated through simulation, and it was confirmed that the accuracy of the maximum error is -1.215 m even in the region where the geoid change is rapid.
|
Optimal Surveillance Trajectory Planning for Illegal UAV Detection for Group UAV using Particle Swarm Optimization
임원호 Wonho Lim , 정형찬 Hyoungchan Jeong , 호등 Teng Hu , 아람기르 Alamgir , 장경희 Kyunghi Chang
24(5) 382-392, 2020
임원호 Wonho Lim , 정형찬 Hyoungchan Jeong , 호등 Teng Hu , 아람기르 Alamgir , 장경희 Kyunghi Chang
DOI: JANT Vol.24(No.5) 382-392, 2020
The use of unmanned aerial vehicle (UAV) have been regarded as a promising technique in both military and civilian applications. Nevertheless, due to the lack of relevant and regulations and laws, the misuse of illegal drones poses a serious threat to social security. In this paper, aiming at deriving the three-dimension optimal surveillance trajectories for group monitoring drones, we develop a group trajectory planner based on the particle swarm optimization and updating mechanism. Together, to evaluate the trajectories generated by proposed trajectory planner, we propose a group-objectives fitness function in accordance with energy consumption, flight risk. The simulation results validate that the group trajectories generated by proposed trajectory planner can preferentially visit important areas while obtaining low energy consumption and minimum flying risk value in various practical situations.
|
Drone Location Tracking with Circular Microphone Array by HMM
정형찬 Hyoungchan , 임원호 Jeongwonho , 곽준봉 Limjunfeng Guo , 이시티아크아메드 Isitiaq Ahmad , 장경희 Kyunghi Chang
24(5) 393-407, 2020
정형찬 Hyoungchan , 임원호 Jeongwonho , 곽준봉 Limjunfeng Guo , 이시티아크아메드 Isitiaq Ahmad , 장경희 Kyunghi Chang
DOI: JANT Vol.24(No.5) 393-407, 2020
In order to reduce the threat by illegal unmanned aerial vehicles, a tracking system based on sound was implemented. There are three main points to the drone acoustic tracking method. First, it scans the space through variable beam formation to find a sound source and records the sound using a microphone array. Second, it classifies it into a hidden Markov model (HMM) to find out whether the sound source exists or not, and finally, the sound source is In the case of a drone, a sound source recorded and stored as a tracking reference signal based on an adaptive beam pattern is used. The simulation was performed in both the ideal condition without background noise and interference sound and the non-ideal condition with background noise and interference sound, and evaluated the tracking performance of illegal drones. The drone tracking system designed the criteria for determining the presence or absence of a drone according to the improvement of the search distance performance according to the microphone array performance and the degree of sound pattern matching, and reflected in the design of the speech reading circuit.
|
Dispersion-Managed Optical Transmission Link Adding of Non-Midway OPC
이성렬 Seong-real Lee
24(5) 408-414, 2020
이성렬 Seong-real Lee
DOI: JANT Vol.24(No.5) 408-414, 2020
The method of overcoming the limitation of optical phase conjugator applied into optical long-haul link for transmitting high capacity wavelength division multiplexed (WDM) channels was investigated. The configuration of optical link was based on dispersion-managed link, in which dispersion compensating fiber inserted into each fiber span with single mode fiber, and optical phase conjugator was added into suitable location of link. The maximum number of fiber spans as a function of the launch power of WDM channels in optical link with optical phase conjugator placed at the proposed location was induced and compared for analyzing the compensation performance of the distorted WDM channels. It was confirmed that the more optical phase conjugator depart from the midway of total transmission length, the less the distorted WDM channels was compensated, however, it was also confirmed that the degradation of compensation can be overcome by the suitable value of residual dispersion per span and by the reasonable choice of fiber span controlling total dispersion accumulated in overall transmission link.
|
Requirements for 6 GHz Unlicensed Bands
강영흥 Young-heung Kang
24(5) 415-422, 2020
강영흥 Young-heung Kang
DOI: JANT Vol.24(No.5) 415-422, 2020
Federal Communications Commissions (FCC) has adopted a new rule that can provide a 1,200 MHz unlicensed spectrum to maximize the public benefits in the 5.925 ~ 7.125 GHz(6 GHz) band by expanding unlicensed broadband into the 6 GHz band while also ensuring that licensed services that operate in the band continue to thrive. In Korea, the M/W band of 6 GHz has been reallocated to introduce unlicensed services in the 6 GHz band. Considering the national interests, the entire 1,200 MHz will be supplied for the indoor uses, but only the 500 MHz of the lower bandwidth (5925 ~ 6425 MHz) will for the outdoor uses under the limited power to protect the incumbent services. The introduction of unlicensed devices is being actively promoted through the reallocation of the 6 GHz M/W band, but since it is desperately necessary to prepare technical requirements to operate them in Korea. In this paper, the US 6 GHz unlicensed rules has been analyzed, these results will be utilized for establishing Korean technical standards with the unlicensed spectrum expansion.
|
Study on Methods of Missile Electromagnetic Susceptibility (EMS) Test
이대현 Dae-hyun Lee , 오택근 Taeckkeun Oh , 오세권 Se-kwon Oh , 김형재 Hyung-jae Kim , 박동현 Dong-hyun Park
24(5) 423-429, 2020
이대현 Dae-hyun Lee , 오택근 Taeckkeun Oh , 오세권 Se-kwon Oh , 김형재 Hyung-jae Kim , 박동현 Dong-hyun Park
DOI: JANT Vol.24(No.5) 423-429, 2020
In this paper, the electromagnetic compatibility (EMC) test standard is described, and the purpose and test configuration for the electromagnetic susceptibility (EMS) test of the missile component and the missile system are confirmed. The test configuration and specifications are suggested by the configuration of the missile component and the missile system based on the US military standards MIL-STD-461F and MIL-STD-464C, and explained that the ungrounded state, the final operating state of the missile component and the missile system, was constructed. In addition, the methods for checking the steady state and the points to be considered during the immunity test were introduced.
|
Implementation of Face Recognition Pipeline Model using Caffe
박진환 Jin-hwan Park , 김창복 Chang-bok Kim
24(5) 430-437, 2020
박진환 Jin-hwan Park , 김창복 Chang-bok Kim
DOI: JANT Vol.24(No.5) 430-437, 2020
The proposed model implements a model that improves the face prediction rate and recognition rate through learning with an artificial neural network using face detection, landmark and face recognition algorithms. After landmarking in the face images of a specific person, the proposed model use the previously learned Caffe model to extract face detection and embedding vector 128D. The learning is learned by building machine learning algorithms such as support vector machine (SVM) and deep neural network (DNN). Face recognition is tested with a face image different from the learned figure using the learned model. As a result of the experiment, the result of learning with DNN rather than SVM showed better prediction rate and recognition rate. However, when the hidden layer of DNN is increased, the prediction rate increases but the recognition rate decreases. This is judged as overfitting caused by a small number of objects to be recognized. As a result of learning by adding a clear face image to the proposed model, it is confirmed that the result of high prediction rate and recognition rate can be obtained. This research will be able to obtain better recognition and prediction rates through effective deep learning establishment by utilizing more face image data.
|
QuTFTP: Quick UDP Trivial File Transfer Protocol
김병국 Byoung-kug Kim
24(5) 438-443, 2020
김병국 Byoung-kug Kim
DOI: JANT Vol.24(No.5) 438-443, 2020
To transfer files between nodes on network based on Ethernet, file transfer protocol (FTP) on TCP/IP and trivial file transfer protocol (TFTP) on UDP/IP are mostly used. Due to the lack of resources (processor, memory and so on) in the embedded system where we generally use for simple works with small firmware like ones; many of the systems implement only UDP/IP for their network stacks. Thus, TFTP is greatly to be preferred. For examples, environmental sensor devices for sensor networks, Boot Loader for general embedded device and preboot execution environment (PXE) boot for PC provide the TFTP. The logic of TFTP is simple for file transmission but, there is Stop-And-Wait problem during the process which occurs long blocking time. In this paper, we propose an algorithm which called QuTFTP(Quick UDP Trivial File Transfer Protocol) to reduce the length of the blocking time and to be compatible with the legacy TFTP.
|
The Multi-legged Small Sized Robot Drive using Piezoelectric Benders
박종만 Jong-man Park , 김영현 Young-hyun Kim , 정원찬 Won-chan Jeong , 류정민 Jeong-min Ryu
24(5) 444-449, 2020
박종만 Jong-man Park , 김영현 Young-hyun Kim , 정원찬 Won-chan Jeong , 류정민 Jeong-min Ryu
DOI: JANT Vol.24(No.5) 444-449, 2020
I proposed small ambulatory robot actuators using piezoelectric benders. In order to make the motion of the biomimetic robot legs similar to the movements of the cockroaches or similar insects, two pairs of legs in the diagonal direction in the four leg structures are required to make the same movement. And elliptical displacement is realized by taking into account horizontal and vertical displacement of multimode oscillations and driving them by electrical signals with differences step by step, for example of 90° the T-shaped robot actuator showed wide range of speed (From 2 mm/sec. up to 266 mm/sec.) and ability of transportation (up to 10 g with 50 mm/s). Locomotive performance of the robot was competitive to the preceding robots, and moreover, the modular type actuators of a segmented myriapods robot could be added and removed for different tasks or performances.
|