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Ku 대역 다중모드 모노펄스 위성추적시스템을 위한 커플러 구현 및 안테나 추적정확도 분석
이재문,임재성,박도현,Lee, Jaemoon,Lim, Jaesung,Park, Dohyun 한국군사과학기술학회 2016 한국군사과학기술학회지 Vol.19 No.3
This paper proposes a Ku-band multi-mode coupler and its monopulse tracking system, which can be applied to a unmaned aircraft vehicle(UAV) platform. In general, the carrier-to-noise(C/N) level of the beacon signal from a Ku-band commercial satellite is relatively weak compared to that of a military satellite because the Ku-band satellite has been designed for commercial services. Therefore, this paper proposes a coupler and its multi-mode monopulse tracking system satisfying the tracking accuracy under a low C/N environment and analyzes the tracking accuracy. After that, we perform a real satellite tracking test and compare the accuracy of the test with the analysis result before validating the performance of the architecture of the proposed satellite tracking system.
한국 국방 연구개발 프로젝트 일정 관리 및 예측을 위한 Earned Schedule 기법의 적용 효과와 한계 분석
조정호,임재성,Cho, Jungho,Lim, Jaesung 한국군사과학기술학회 2018 한국군사과학기술학회지 Vol.21 No.3
Earned Value Management(EVM) has been used to manage and forecast defense project schedule and cost over the last two decades in the world. However to support the lacking ability of schedule analysis in traditional EVM, earned schedule(ES) has been introduced as a tool to more accurately estimate schedule performance. This paper compares which method EVM or ES, provides more accurate schedule predictors in 32 Korean defense research and development projects. As a result of comparison, the ES method can predict the future schedule more reliably than the EVM method. We also analyze early warning function of schedule performance index considering project duration extension point. Through the analysis results, we confirm that both the EVM and the ES method lack the ability of the early warning in terms of the current schedule management criterion.
사이버공격의 정량적 피해평가를 통한 공세적 대응규모 산정
홍병진,임재성,김완주,조재명,Hong, Byoungjin,Lim, Jaesung,Kim, Wanju,Cho, Jaemyoung 한국융합보안학회 2017 융합보안 논문지 Vol.17 No.4
Various cyber attacks against our society and the government are continuing, and cases and damages are reported from time to time. And the area of cyber attack is not limited to cyberspace, but it is expanding into physical domain and affecting it. In the military arena, we have established and implemented the principle of responding proportionally to enemy physical attacks. This proportionality principle is also required in the version where the region is expanding. In order to apply it, it is necessary to have a quantitative and qualitative countermeasure against cyber attack. However, due to the nature of cyber attacks, it is not easy to assess the damage accurately and it is difficult to respond to the proportionality principle and the proportional nature. In this study, we calculated the damage scale by quantitatively and qualitatively evaluating the cyber attack damage using the Gorden-Lobe model and the security scoring technique based on the scenario. It is expected that the calculated results will be provided as appropriate level and criterion to counteract cyber attack. 우리사회와 정부에 대한 다양한 사이버 공격이 지속적으로 이루어지고 있으며 수시로 그 사례 및 피해가 발표되고 있다. 그리고 사이버공격의 영역 또한 사이버공간에 국한되는 것이 아니라 물리적 영역으로 확대되어 영향을 미치고 있다. 군사적 영역에서는 적의 물리적 공격에 대해 비례성을 갖고 대응한다는 원칙을 수립하고 시행하고 있다. 영역이 확대되고 있는 사이버전에서도 이러한 비례성 원칙이 필요할 것으로 판단되며, 실제 적용하기 위해서는 사이버공격에 대한 정량적, 정성적 대응기준을 가지고 있어야 할 것이다. 그러나 사이버공격의 특성상 정확한 피해평가가 쉽지 않아 비례성이 모호하며 비례성 원칙으로 대응하는 것도 어려울 것이다. 이에 본 연구에서는 시나리오를 기반으로 사이버공격이 조직이나 시스템에 미치는 영향을 Gorden-Lobe 모델과 시큐리티 스코어링 기법을 이용하여, 사이버 공격 피해를 정량적 정성적으로 평가하여 피해규모를 산출하였다. 산출된 결과는 사이버공격에 대한 공세적으로 대응하기 위한 적절한 수준과 기준으로 제공할 것으로 기대한다.
고속 도플러 편이 환경에서 최적 시간지연을 갖는 다중모드 모노펄스 신호처리에 관한 연구
이재문,임재성,안희수,Lee, Jaemoon,Lim, Jaesung,Ahn, Huisoo 한국군사과학기술학회 2016 한국군사과학기술학회지 Vol.19 No.5
Multi-mode monopulse system is widely used for satellite terminal like UAV because of high tracking accuracy and low size/weight profile. In order to calculate tracking error, Multi-mode monopulse system utilizes high-order mode signal, and it should have enough C/N(carrier to noise) level therefore tracking system needs narrow band filtering of received satellite beacon signal as much as possible. However, UAV suffers for beacon frequency drift derived from Doppler effect due to satellite figure 8 movement and UAV maneuvering. Therefore wideband signal processing needs to be considered in advance for exact doppler compensation and consequent time delay. In this paper, we propose the multi-stage Digital Signal processing system for beacon signal, which could minimize the signal delay under high Doppler and low C/N condition.
뚜언,이민우,임재성,Tuan, Vu Quoc,Lee, Minwoo,Lim, Jaesung 한국정보통신학회 2022 한국정보통신학회논문지 Vol.26 No.12
In the era of Fourth Industrial Revolution, secure networking technology is playing an essential role in the defense weapon systems. Encryption technology is used for information security. The safety of cryptographic technology, according to Kerchoff's principles, is based on secure key management of cryptographic technology, not on cryptographic algorithms. However, traditional centralized key management is one of the problematic issues in battlefield environments since the frequent movement of the forces and the time-varying quality of tactical networks. Alternatively, the system resources of each node used in the IoBT(Internet of Battlefield Things) environment are limited in size, capacity, and performance, so a lightweight key management system with less computation and complexity is needed than a conventional key management algorithm. This paper proposes a novel key escrow scheme in a lightweight manner for the IoBT environment. The safety and performance of the proposed technique are verified through numerical analysis and simulations.
김상수,구성모,임재성,Kim, Sangsoo,Gu, Sungmo,Lim, Jaesung 한국군사과학기술학회 2014 한국군사과학기술학회지 Vol.17 No.5
The Republic of Korea Army is using R-NAD of MIL-STD-188-220 as a Media Access Control protocol. Under urgent situations, almost all stations transmit data frames and then the network will reach a saturation state. Several articles have been devoted to the study of R-NAD performance. However, most of them focus on comparing the performance of some NADs using network simulation tools. We propose an analytical model to compute the throughput of R-NAD under the assumption of a network traffic saturation. Analytical results were verified by Monte Carlo methods. We have shown that the performance of a success probability and an average idle time remains almost unchanged as the total number of stations increases. We have also shown that Type 1/2/4 operation mode outperforms Type 3 operation mode in throughput. The results showed that the system with a squelch detection achieved a better performance than the one without it. The longer DATA time had a higher throughput.
전파 지연이 긴 공중 전술 TDMA 네트워크에서 송신자 간 거리 기반 보호 시간 제어 기법
백호기(Hoki Baek),임재성(Jaesung Lim),구자열(Jayeul Koo),오일혁(Ilhyuk Oh) 한국통신학회 2012 韓國通信學會論文誌 Vol.37 No.11(융합기술)
공중 전술 네트워크는 공대공 또는 공대지 작전에 사용되고 전파 지연이 크다는 특징이 있다. 모든 노드는 TDMA 기반의 브로드캐스팅을 사용하여 데이터를 공유한다. 공중 전술 네트워크에서는 긴 전파 지연으로 인한 충돌 때문에, 브로드캐스팅을 보장하기 위해서는 각 타임 슬롯마다 보호 시간이 필요하다. 그러나 보호 시간의 낭비로 인해 네트워크의 채널 이용률이 크게 저하될 수 있다. 본 논문에서는 송신자 간 거리 정보를 사용하여 보호 시간의 낭비를 줄여 채널 이용률을 향상시키면서 브로드캐스팅을 보장하는 Inter-Transmitter Distance-Based TDMA(ID-TDMA) 기법을 제안한다. 그리고 성능 평가를 통해 ID-TDMA의 효과성을 확인하였다. Airborne tactical networks is used to air-to-air or air-to-ground operation and have a large propagation delay. All nodes share the data by using TDMA-based broadcasting. In airborne tactical networks, each time slot needs the guard time to ensure the broadcasting because the collisions occur due to the large propagation delay. However, the channel utilization of the networks can be greatly degraded due to the waste of guard time. In this paper, we propose Inter-Transmitter Distance-Based TDMA (ID-TDMA) scheme which ensures the broadcasting while improving the channel utilization by reducing the guard time with the inter-transmitter distance information. The proposed scheme shows the effectiveness through the performance evaluation.