The Development of Air-based Space Launch Vehicle for small satellites
조태환 Taehwan Cho , 이성섭 Soungsub Lee
25(4) 267-272, 2021
조태환 Taehwan Cho , 이성섭 Soungsub Lee
DOI: JANT Vol.25(No.4) 267-272, 2021
The end of the ROK-U.S. missile guidelines opened up the possibility of developing space launch vehicles for various platforms based on air and sea. In particular, the air-based space launch vehicle is an essential space power projection capability compared to the ground-based space launch vehicle in consideration of the geographical location of the Korean Peninsula, such as the deployment of various satellite orbits and the timely launch of satellite. In addition, compared to the ground-based launch vehicle, the cost reduction effect is large, and it has the merit of energy gain because it can be launched with the advantage of the aircraft’s altitude and speed. Therefore, in this paper, the necessity of air-based space launch vehicle in the strategic environment of the Korean Peninsula is clearly presented, and through technology trend analysis of various air launch vehicle, the three methods are proposed to have the most efficient air-based space launch vehicle capability in the Korean situation.
|
Synchronization Method Design of Redundant Flight Control Computer for UAV
이영서 Young Seo Lee , 강신우 Shin Woo Kang , 이희곤 Hee Gon Lee , 안태식 Tae-sik Ahn
25(4) 273-279, 2021
이영서 Young Seo Lee , 강신우 Shin Woo Kang , 이희곤 Hee Gon Lee , 안태식 Tae-sik Ahn
DOI: JANT Vol.25(No.4) 273-279, 2021
A flight control computer(FLCC) applied to an unmanned aerial vehicle(UAV) is a safety-critical item, and which is designed in a multiple structure to increase the reliability of operation by securing fault tolerance. These FLCC of multiple structure should be designed so that each independent processing/control components can perform the same operation at the same time. And for this reason, a synchronization algorithm for synchronizing the operation between FLCCs should be included in an operational flight program. In this paper, we propose a software design method for synchronization between dual FLCCs applied to UAVs. The proposed synchronization method is designed to synchronize using only the minimum hardware resources to reduce a failure rate. In addition, the proposed synchronization method is designed to minimized synchronization errors due to a timer operation by designing in consideration of operation characteristics of the hardware timer used for the synchronization.
|
The Show up Time in the Development of the Korean Pilots Fatigue Management Program
이승영 Lee Seungyoung , 정승섭 Chung Seung Sup , 김현덕 Kim Hyeon Deok
25(4) 280-285, 2021
이승영 Lee Seungyoung , 정승섭 Chung Seung Sup , 김현덕 Kim Hyeon Deok
DOI: JANT Vol.25(No.4) 280-285, 2021
The significance of pilots' fatigue and the attributed risk management had continuously increased over time as the airline industry expanded. Research and legislation efforts associated with pilot fatigue are being taking place actively all over the world. In the developed world such as the United States and European Union etc., the airline pilot fatigue is already being managed by considering the show up time, the number of take offs and landings made, resting period, jet lag etc., when computing flight duty time. In Korea, the flight duty time is only limited by the total number of hours per given period regardless of the flight conditions and environment. Such lack of regulation demand development of a fatigue management program. According to the survey taken from the airline pilots in Korea, it has been found that acquiring foreign policies directly may in turn, increase the risk of fatigue. This research suggest future studies regarding fatigue management program adapted exclusively to Korean domestic flight environment and culture.
|
Optical Transmission Link with Dispersion Map of Antipodal Symmetry and OPC
이성렬 Seong-real Lee
25(4) 286-292, 2021
이성렬 Seong-real Lee
DOI: JANT Vol.25(No.4) 286-292, 2021
Dispersion maps of antipodal symmetric type for improvement of compensation effect in dispersion managed link combined with optical phase conjugation, which can compensate for the distorted wavelength division multiplexed (WDM) signals due to chromatic dispersion and nonlinear Kerr effects of single-mode fiber, were proposed. It was confirmed that the proposed all of antipodal symmetric dispersion maps was more effective to compensate for the distorted WDM channels than the conventional link of uniform type dispersion map. Especially, dispersion maps formed like the inversion of alphabet S were more advantageous as the distorted WDM channels were compensated than dispersion maps formed like alphabet S. It was expected that the variety of optical network topology was more expanded by applying the proposed antipodal symmetric dispersion maps into transmission link.
|
Inspection of guided missiles applied with parallel processing algorithm
정의재 Eui-jae Jung , 고상훈 Sang-hoon Koh , 이유상 You-sang Lee , 김영성 Young-sung Kim
25(4) 293-298, 2021
정의재 Eui-jae Jung , 고상훈 Sang-hoon Koh , 이유상 You-sang Lee , 김영성 Young-sung Kim
DOI: JANT Vol.25(No.4) 293-298, 2021
In general, the guided weapon seeker and the guided control device process the target, search, recognition, and capture information to indicate the state of the guided missile, and play a role in controlling the operation and control of the guided weapon. The signals required for guided weapons are gaze change rate, visual signal, and end-stage fuselage orientation signal. In order to process the complex and difficult-to-process missile signals of recent missiles in real time, it is necessary to increase the data processing speed of the missiles.
This study showed the processing speed after applying the stop and go and inverse enumeration algorithm among the parallel algorithm methods of PINQ and comparing the processing speed of the signal data required for the guided missile in real time using the guided missile inspection program. Based on the derived data processing results, we propose an effective method for processing missile data when applying a parallel processing algorithm by comparing the processing speed of the multi-core processing method and the single-core processing method, and the CPU core utilization rate.
|
Design and Implementation of CNN-Based Human Activity Recognition System using WiFi Signals
정유신 You-shin Chung , 정윤호 Yunho Jung
25(4) 299-304, 2021
정유신 You-shin Chung , 정윤호 Yunho Jung
DOI: JANT Vol.25(No.4) 299-304, 2021
Existing human activity recognition systems detect activities through devices such as wearable sensors and cameras. However, these methods require additional devices and costs, especially for cameras, which cause privacy issue. Using WiFi signals that are already installed can solve this problem. In this paper, we propose a CNN-based human activity recognition system using channel state information of WiFi signals, and present results of designing and implementing accelerated hardware structures. The system defined four possible behaviors during studying in indoor environments, and classified the channel state information of WiFi using convolutional neural network (CNN), showing and average accuracy of 91.86%. In addition, for acceleration, we present the results of an accelerated hardware structure design for fully connected layer with the highest computation volume on CNN classifiers. As a result of performance evaluation on FPGA device, it showed 4.28 times faster calculation time than software-based system.
|
Design of FMCW Radar Signal Processor for Human and Objects Classification Based on Respiration Measurement
이윤구 Yungu Lee , 윤형석 Hyeongseok Yun , 김수연 Suyeon Kim , 허성욱 Seongwook Heo , 정윤호 Yunho Jung
25(4) 305-312, 2021
이윤구 Yungu Lee , 윤형석 Hyeongseok Yun , 김수연 Suyeon Kim , 허성욱 Seongwook Heo , 정윤호 Yunho Jung
DOI: JANT Vol.25(No.4) 305-312, 2021
Even though various types of sensors are being used for security applications, radar sensors are being suggested as an alternative due to the privacy issues. Among those radar sensors, PD radar has high-complexity receiver, but, FMCW radar requires fewer resources. However, FMCW has disadvantage from the use of 2D-FFT which increases the complexity, and it is difficult to distinguish people from objects those are stationary. In this paper, we present the design and the implementation results of the radar signal processor (RSP) that can distinguish between people and object by respiration measurement using phase estimation without 2D-FFT. The proposed RSP is designed with Verilog-HDL and is implemented on FPGA device. It was confirmed that the proposed RSP includes 6,425 LUT, 4,243 register, and 12,288 memory bits with 92.1% accuracy for target's breathing status.
|