Analysis and Improvement on Process of Mission Autonomy in UxAS
김윤근 Yungeun Kim
27(1) 1-7, 2023
김윤근 Yungeun Kim
DOI: JANT Vol.27(No.1) 1-7, 2023
Mission autonomy system should be embedded on UAV (Unmanned Aerial Vehicle) for mosaic warfare where UAVs autonomously assign tasks to themselves. UxAS (Unmanned x-systems Autonomy Service) proposed by Air Force Research Laboratory is mission autonomy system for unmanned platforms. UxAS has extensible structure composed of numerous module services. However, UxAS can conduct mission autonomy process only when an operator sends an autonomy request. In this paper, We analyze the process of mission autonomy in UxAS, and propose an improved structure of UxAS where mission autonomy process is autonomously triggered by situation awareness service without the request of the operator. The proposed process was validated by simulation.
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A Study on the Development of Helicopter Accident Prevention Program by Spatial Disorientation
조영진 Young-jin Cho
27(1) 8-15, 2023
조영진 Young-jin Cho
DOI: JANT Vol.27(No.1) 8-15, 2023
According to the results of a survey of pilots, 92% or 230 out of 252 respondents said they had experienced flight errors during flight. As so many pilots are experiencing Spatial Disorientation, and this is one of the main causes of aircraft accidents and loss of life, so it is important to understand accurately. However, in Korea, training equipment for fixed-wing pilots has already been developed and trained, or recently developed, and some equipment for helicopter pilots is available in the Korea Air Force, but there is no environment for helicopter pilots to receive training in Spatial Disorientation prevention. Therefore, we intend to produce a helicopter-only simulator, present a program to prevent possible Spatial Disorientation during flights for helicopter pilots, and propose legal and institutional measures based on future training data.
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A Study on the Response to Acts of Unlawful Interference by Insider Threat in Aviation Security
임상훈 Sang-hoon Lim , 허백용 Baek-yong Heo , 황호원 Ho-won Hwang
27(1) 16-22, 2023
임상훈 Sang-hoon Lim , 허백용 Baek-yong Heo , 황호원 Ho-won Hwang
DOI: JANT Vol.27(No.1) 16-22, 2023
Terrorists have been attacking in the vulnerable points of aviation sector with the diverse methods of attacks. Recently, Vulnerability is increasing because the Modus Operandi of Terrorism is carried out by exploitation of people in the form of employee working in aviation sector whose role provides them with privileged access to secured locations, secured items or security sensitive information. Furthermore, cases of insider threat are rising across the world with the phenomenon of personal radicalization through internet and social network service. The government of ROK must respond to insider threat could exploit to acts of unlawful interference and the security regulations should be established to prevent from insider threat in advance refer to the acts of unlawful interference carried out in foreign countries and the recommendations by USA, UK and ICAO.
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김학근 Hak-keun Kim , 김규왕 Kyu-wang Kim
27(1) 23-35, 2023
김학근 Hak-keun Kim , 김규왕 Kyu-wang Kim
DOI: JANT Vol.27(No.1) 23-35, 2023
Evidence-based training (EBT) improves a pilot’s competency and confidence based on the data(Evidence) from actual aircraft accidents, incidents, operations, and training for safe operation in the fast-paced and large-scale air transportation field. It is a training/assessment program that strengthens resilience for problem solving. As a way to apply this evidence-based training(EBT) to the educational system of ATO and to resolve the problems, I propose 3 improvement plans. They are evaluation criteria that apply the core competencies of EBT to the educational evaluation system, the way to improve the system for standardization of practical test examiners and instructors and also the ways to use Flight Simulation Training Devices(FSTD).
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A Study on the Traffic Simulation for Autonomous Vehicles Considering Weather Environment
이서영 Seo-young Lee , 용성중 Sung-jung Yong , 박효경 Hyo-gyeong Park , 유연휘 Yeon-hwi You , 문일영 Il-young Moon
27(1) 36-42, 2023
이서영 Seo-young Lee , 용성중 Sung-jung Yong , 박효경 Hyo-gyeong Park , 유연휘 Yeon-hwi You , 문일영 Il-young Moon
DOI: JANT Vol.27(No.1) 36-42, 2023
The development of autonomous vehicles are currently being actively carried out by various companies and research institutes. Expectations for commercialization in daily life as well as specific industries are also rising. Simulators for autonomous vehicles are an essential element in algorithm development and execution considering stability and cost. In this need, various simulators and platforms for simulators are emerging, but research on simulations that reflect various meteorological environmental factors in the real world is still insufficient. This paper proposes a traffic simulation for autonomous vehicles that can consider the weather environment. The weather environment that can be set is largely classified into four categories, and an improved collision prevention algorithm to apply them is presented. Simulation development was conducted through Carla's Python API, a development tool for autonomous driving, and the performance results were compared with existing collision algorithms. Through this, we tried to propose improvements for the development of advanced self-driving vehicle simulations that can reflect various weather environmental factors in real life.
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Object Tracking Using Weighted Average Maximum Likelihood Neural Network
박선배 Sun-bae Park , 유도식 Do-sik Yoo
27(1) 43-49, 2023
박선배 Sun-bae Park , 유도식 Do-sik Yoo
DOI: JANT Vol.27(No.1) 43-49, 2023
Object tracking is being studied with various techniques such as Kalman filter and Luenberger tracker. Even in situations, such as the one in which the system model is not well specified, to which existing signal processing techniques are not successfully applicable, it is possible to design artificial neural networks to track objects. In this paper, we propose an artificial neural network, which we call 'maximum-likelihood weighted-average neural network', to continuously track unpredictably moving objects. This neural network does not directly estimate the locations of an object but obtains location estimates by making weighted average combining various results of maximum likelihood tracking with different data lengths. We compare the performance of the proposed system with those of Kalman filter and maximum likelihood object trackers and show that the proposed scheme exhibits excellent performance well adapting the change of object moving characteristics.
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Analysis on Influence of Errors for Dual-axis Rotational Inertial Navigation System Performance
조민수 Minsu Jo , 박찬주 Chanju Park
27(1) 50-56, 2023
조민수 Minsu Jo , 박찬주 Chanju Park
DOI: JANT Vol.27(No.1) 50-56, 2023
INS(Inertial Navigation System) calculates navigation information using a vehicle’s acceleration and angular velocity without the outside information. However, when navigation is performed for a long time, navigation error gradually diverges and the performance decreases. To enhance INS’s performance, the rotation of inertial measurement unit is developed to compensate error sources of inertial sensors, which is called RINS(Rotational Inertial Navigation System). This paper analyzes the influence of several errors for dual-axis RINS and the shows the results using simulation.
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Compact Tri-Band Bandpass Filter Using Dual-Mode Stepped- Impedance Resonators and Parallel Coupled-Lines
성규제 Gyuje Sung , 김영 Young Kim
27(1) 57-62, 2023
성규제 Gyuje Sung , 김영 Young Kim
DOI: JANT Vol.27(No.1) 57-62, 2023
This paper proposes a tri-band bandpass filter using dual-mode stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with open stubs and parallel coupled lines (PCLs) that have inter-digital and comb-line shorted ends. Two U-shaped SIRs with open stubs build the first and third passband, and the central PCL resonators build the second passband. Five resonators and coupling structures are theoretically analyzed to derive the scattering parameters of the proposed filter. A novel tri-band bandpass filter is designed and fabricated using the induced scattering parameters. The measured result of the fabricated tri-band bandpass filter shows a good agreement with the simulated one.
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A Rotary Capacitive-Wireless Power Transfer System for Power Supply of a Wireless Sensor System on Marine Rotating Shaft
호앙반아이 Van Ai Hoang , 이영철 Young Chul Lee
27(1) 63-70, 2023
호앙반아이 Van Ai Hoang , 이영철 Young Chul Lee
DOI: JANT Vol.27(No.1) 63-70, 2023
In this work, a capacitive wireless power transfer (C-WPT) system is presented for wireless sensor system (WSS) applications in marine propulsion shafts. For a single Q factor on both sides of the coupling capacitor and reactive power removal from the circuit, a double-sided LCLC converter and transformers topology are designed to drive the rotary C-WPT system for WSS on the shaft. Parallel-connected parallel plate rotating capacitors with a capacitance of 170 pF are designed and implemented for the C-WPT system on a snow rotating shaft. In the experimental results, the C-WPT system achieved a transmission efficiency of 66.67% with 7.8 W output power at 3 mm distance and 1 MHz operating frequency. Therefore, it was proved that the fabricated C-WPT system can supply power to the WSS of the rotating shaft.
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여준호 Junho Yeo
27(1) 71-76, 2023
여준호 Junho Yeo
DOI: JANT Vol.27(No.1) 71-76, 2023
In this paper, a humidity sensor using a microstrip patch antenna(MPA) and polyvinyl alcohol(PVA) is studied. PVA is a polymer material whose permittivity changes with humidity, and a rectangular slot is added to the radiating edge of the MPA, which is sensitive to changes in electric field, in order to increase the sensitivity to changes in relative permittivity. After thinly coating the area around the radiating edge with the rectangular slot of the MPA fabricated on a 0.76 mm-thick RF-35 substrate with PVA, the changes in the resonant frequency and magnitude of the MPA’s input reflection coefficient are measured when relative humidity is adjusted from 40% to 80% in 10% increments at a temperature of 25 degrees using a temperature and humidity chamber. Experiment results show that when the relative humidity increases from 40% to 80%, the resonance frequency of the antenna’ input reflection coefficient decreases from 2.447 GHz to 2.418 GHz, whereas the magnitude increases from -7.112 dB to -3.428 dB.
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Conceptual design and sensitivity analysis of a tilt + stopped rotor type eVTOL using motor weight estimation formula and iterative design
이주헌 Ju-heon Lee , 김태종 Taejong Kim , 장서윤 Seo-yoon Jang , 조희수 Hui-su Jo , 황호연 Ho-yon Hwang
27(1) 77-94, 2023
이주헌 Ju-heon Lee , 김태종 Taejong Kim , 장서윤 Seo-yoon Jang , 조희수 Hui-su Jo , 황호연 Ho-yon Hwang
DOI: JANT Vol.27(No.1) 77-94, 2023
In this study, the conceptual design of a tilt + stopped rotor type electric vertical take-off and landing (eVTOL) aircraft was performed using design iteration. Based on Hyundai Motor's S-A1, the mission profile was defined using the concept of urban air mobility (UAM), and configuration design and aerodynamic analysis were performed using OpenVSP and XFLR5 software. After estimating the required power for the designed eVTOL, the required performance of the battery and the maximum take-off weight (MTOW) were calculated. . It was iteratively calculated using Microsoft Excel and Visual Basic Application, and a new electric motor weight estimation formula was derived. Also, the sensitivity analyses of each design variables of an eVTOL was performed using the automated program.
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Energy Harvester on a Ship Propulsion Shaft for Wireless Sensor System Applications
호앙반아이 Van Ai Hoang , 이영철 Young Chul Lee
27(1) 96-101, 2023
호앙반아이 Van Ai Hoang , 이영철 Young Chul Lee
DOI: JANT Vol.27(No.1) 96-101, 2023
In this work, an energy harvester (EH) on the rotating shaft has been proposed for a wireless sensor system (WSS) applications. The EH was designed and implemented to the shaft with a diameter of 20 cm to continuously power a wireless sensor system (WSS). The rotor has coils wound in pairs on seven U-shaped cores attached to the shaft. The stator consists of eight pairs of magnets attached to eight I-cores and they are fixed to an outer fixture. The generated power of the EH was investigated as function of the air gap between the rotor and stator, the number of turn of coils, and shaft speed. The fabricated EH produced power up to 2.87 W at 300 rpm and the 3 mm air gap.
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고상훈 Sang-hoon Koh , 송호진 Ho-jin Song , 금남호 Nam-ho Keum , 유필중 Pil-joong Yoo , 오세권 Se-kwon Oh , 김영성 Young-sung Kim
27(1) 102-110, 2023
고상훈 Sang-hoon Koh , 송호진 Ho-jin Song , 금남호 Nam-ho Keum , 유필중 Pil-joong Yoo , 오세권 Se-kwon Oh , 김영성 Young-sung Kim
DOI: JANT Vol.27(No.1) 102-110, 2023
The MATS(Missile Assembly Test Set) is manufactured and used to check the function of the missile during the period of development for the guided missile system, and the requirements for power and communication are managed for equipment production. The MATS developer implements software according to the proposed communication standard to guarantee the reliability of the data that communicates with the guided missile. The test bed is built and self-performance evaluation is performed after implementation. And the verification process is performed using the standard equipment. The characteristics of periodic delay for data transmission must be reflected when building a test bed. This paper describes a test bed construction method for data processing with periodic delay. Also This paper compares and evaluates the performance by changing the previously designed algorithm.
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Machine Learning Model for Predicting the Residual Useful Lifetime of the CNC Milling Insert
최원근 Won-gun Choi , 김흥섭 Heungseob Kim , 고봉진 Bong Jin Ko
27(1) 111-118, 2023
최원근 Won-gun Choi , 김흥섭 Heungseob Kim , 고봉진 Bong Jin Ko
DOI: JANT Vol.27(No.1) 111-118, 2023
For the implementation of a smart factory, it is necessary to collect data by connecting various sensors and devices in the manufacturing environment and to diagnose or predict failures in production facilities through data analysis. In this paper, to predict the residual useful lifetime of milling insert used for machining products in CNC machine, weight k-NN algorithm, Decision Tree, SVR, XGBoost, Random forest, 1D-CNN, and frequency spectrum based on vibration signal are investigated.
As the results of the paper, the frequency spectrum does not provide a reliable criterion for an accurate prediction of the residual useful lifetime of an insert. And the weighted k-nearest neighbor algorithm performed best with an MAE of 0.0013, MSE of 0.004, and RMSE of 0.0192. This is an error of 0.001 seconds of the remaining useful lifetime of the insert predicted by the weighted-nearest neighbor algorithm, and it is considered to be a level that can be applied to actual industrial sites.
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A Study on Operational Improvements for Reducing Carbon Emissions from Aviation
김성미 Sung-mi Kim , 김은미 Eun-mi Kim , 임상훈 Sang-hoon Lim , 황호원 Ho-won Hwang
27(1) 119-125, 2023
김성미 Sung-mi Kim , 김은미 Eun-mi Kim , 임상훈 Sang-hoon Lim , 황호원 Ho-won Hwang
DOI: JANT Vol.27(No.1) 119-125, 2023
It is necessary to reduce aviation GHG(CO2) emission to ensure aviation sustainable development. Operational improvements may not contribute significantly to carbon reduction but it can sustatially reduce emission in a short term. ICAO has developed GANP and ASBU to optimize operations and countries are making efforts to expand infrastructure and develop technology. The legal barriers to operational improvement are based on the notion of state sovereignty under the Chicago Convention which allows countries to control inefficiencies based on borders or limit or prohibit the passage of aircraft. Chicago Convention does not grant unlimited freedom of air sovereignty and if the concept of state sovereignty is interpreted according to the times it is possible to achieve smooth operational improvement.
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Object Recognition Using Local Binary Pattern Based on Confidence Measure
이용걸 Yonggeol Lee
27(1) 126-132, 2023
이용걸 Yonggeol Lee
DOI: JANT Vol.27(No.1) 126-132, 2023
Object recognition is a technology that detects and identifies various objects in images and videos. LBP is a descriptor that operates robustly to illumination variations and is actively used in object recognition. LBP considers the range of neighboring pixels, the order of combining the neighbors after the comparison operation, and the starting position of combining. In particular, the starting position of the LBP becomes the "most significant bit"; it dramatically affects the performance of object recognition. In this paper, based on the N starting positions, the data most similar to the input data are searched in each of the N feature spaces. Object recognition is performed by the confidence measure that can compare different results of each feature space under the same criterion and select the most reliable result. In the experimental results, it was confirmed that there is a difference in performance depending on the starting position of LBP. The proposed method showed a high performance of up to 12.66% compared to the recognition performance of the existing LBP.
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Data Quality Assessment and Improvement for Water Level Prediction of the Han River
최지현 Ji-hyun Choi , 강진엽 Jin-yeop Kang , 안현 Hyun Ahn
27(1) 133-138, 2023
최지현 Ji-hyun Choi , 강진엽 Jin-yeop Kang , 안현 Hyun Ahn
DOI: JANT Vol.27(No.1) 133-138, 2023
As a side effect of recent rapid climate change and global warming, the frequency and scale of flood disasters are increasing worldwide. In Korea, the water level of the Han River is a major management target for preventing flood disasters in Seoul, the capital of Korea. In this paper, to improve the water level prediction of the Han River based on machine learning, we perform a comprehensive assessment of the quality of related dataset and propose data preprocessing methods to improve it. Specifically, we improve the dataset in terms of completeness, validity, and accuracy through missing value processing and cross-correlation analysis. In addition, we conduct a performance evaluation using random forest and LightGBM to analyze the effect of the proposed data improvement method on the water level prediction performance of the Han River.
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Telemedicine robot system for visual inspection and auscultation using WebRTC
박재삼 Jae-sam Park
27(1) 139-145, 2023
박재삼 Jae-sam Park
DOI: JANT Vol.27(No.1) 139-145, 2023
When a doctor examines a patient in a hospital, the doctor directly checks the patient's condition and conducts a face-to-face diagnosis through dialogue with the patient. However, it is often difficult for doctors to directly treat patients. Recently, several types of telemedicine systems have been developed. However, the systems have lack of capabilities to observe heart disease, neck condition, skin condition, inside ear condition, etc. To solve this problem, in this paper, an interactive telemedicine robot system with autonomous driving in a room capable of visual examination and auscultation of patients is developed. The developed robot can be controlled remotely through the WebRTC platform to move toward the patient and check a patient's condition under the doctor's observation using the multi-joint robot arm. The video information, audio information, patient's heart sound, and other data obtained remotely from patients can be transmitted to a doctor through the web RTC platform. The developed system can be applied to the various places where doctors are not possible to attend.
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Purchase and Acquisition Order System for sharing on factory
서연경 Youn-kyoung Seo
27(1) 146-153, 2023
서연경 Youn-kyoung Seo
DOI: JANT Vol.27(No.1) 146-153, 2023
In accordance with the industrial convergence regulation sandbox decision promoted by the Ministry of Trade, Industry and Energy, the “machine tool sharing service in the factory” applied for by MyMaker Co., Ltd., an industry-academia cooperation company, was granted a demonstration exception. While implementing this, in a situation where the ordering service part had to be developed as software, the company's domain problems were identified and analyzed, procedures were established, and a system was designed that met the related requirements. As a joint research and development project to solve the difficulties of the LINC+ industry, the order-to-order system was finally developed for shared factory services. In accordance with the procedure and requirements analysis, the planning, design, prototyping, and implementation production stages were carried out. Finally, it was confirmed that the final development contents were well implemented according to the requirements, and the resolution of the difficulties was confirmed through functional verification demonstrations.
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