• Title/Summary/Keyword: defense performance

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Adversarial Detection with Gaussian Process Regression-based Detector

  • Lee, Sangheon;Kim, Noo-ri;Cho, Youngwha;Choi, Jae-Young;Kim, Suntae;Kim, Jeong-Ah;Lee, Jee-Hyong
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.8
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    • pp.4285-4299
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    • 2019
  • Adversarial attack is a technique that causes a malfunction of classification models by adding noise that cannot be distinguished by humans, which poses a threat to a deep learning model. In this paper, we propose an efficient method to detect adversarial images using Gaussian process regression. Existing deep learning-based adversarial detection methods require numerous adversarial images for their training. The proposed method overcomes this problem by performing classification based on the statistical features of adversarial images and clean images that are extracted by Gaussian process regression with a small number of images. This technique can determine whether the input image is an adversarial image by applying Gaussian process regression based on the intermediate output value of the classification model. Experimental results show that the proposed method achieves higher detection performance than the other deep learning-based adversarial detection methods for powerful attacks. In particular, the Gaussian process regression-based detector shows better detection performance than the baseline models for most attacks in the case with fewer adversarial examples.

A Study on the Method of Analyzing the Topography Characteristics of the Main Maneuvering Test Site for the Selection of the Representative Drive Course of Combat Vehicles (전투차량 대표주행경로 선정을 위한 주행시험장 지형 특성 분석 기법 연구)

  • Kim, Juhee;Choi, Hyunho
    • Journal of the Korea Institute of Military Science and Technology
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    • v.24 no.3
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    • pp.293-301
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    • 2021
  • LTV(Light Tactical Vehicle) operating in our military requires higher levels of performance and durability to withstand harsher conditions than general vehicles, as they must travel on both rough-train and off-road as well as on public roads. Recently, LTV development is demanded a variety of test evaluations in order to satisfy ROC (Required Operational Capability) by the military requirement. However, there is no informations of driving test course for satisfying the durability performance of Korean tactical vehicle. Therefore, this study aims to provide basic data to establish reliable drive test conditions by analyzing the main maneuvering test site at the domestic and foreign country in order to select the representative drive course. These studies will provide a more scientific and systematic evaluation solution for the development of tactical vehicles, and can be effectively used to establish a certified system for military vehicle test evaluation in the future

Development and Verification of Wireless Check-up System of POD for Captive Flight Test (탑재비행시험용 POD 무선 점검 시스템 개발 및 검증)

  • Ko, Myoungjun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.24 no.2
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    • pp.204-210
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    • 2021
  • In this paper, we studied a method of wirelessly checking up the POD for captive flight tests which is performed during the development of guided weapons systems. The wireless power transfer module, the power distribution device, and the battery pack were designed to wirelessly power the captive flight test POD, and the communication device was designed to enable wireless communication between the POD and the check-up device. The communication device was designed to enable WiFi, IR communication, and laser diode communication, so that various communication methods could be tested. Through the performance test, it was confirmed that power was stably supplied to the captive flight test POD, and the wireless communication performance was verified by measuring the delay time and error rate. As a result, by using our system the POD check-up for the captive flight test was performed wirelessly and the data of the captive equipment could be obtained effectively.

The Study on the Performance Prediction of Precision Linear Shaped Charge Using Numerical Analysis Method (수치해석 기법을 이용한 정밀선상성형장약의 성능 예측에 관한 연구)

  • Lee, Sieun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.25 no.3
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    • pp.275-284
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    • 2022
  • Linear Shaped Charge(LSC) is widely used as a separation system in the field of weapon system. However, there are some disadvantages that are charging lots of explosives due to lack of uniformity and having difficulties of the design of liner and explosives because of manufacturing process. In order to solve these problems, Precision Linear Shaped Charge(PLSC) that can design a liner independently and charge explosives uniformly has been developed. In this study, PLSC was designed to have a proper liner shape and amount of explosives, and the penetration test of PLSC with different stand-off distance from liner to target was conducted. On the basis of the penetration test results of PLSC, the numerical analysis method using AUTODYN was established and verified. The penetrative mechanism and characteristics of PLSC with targets of different materials was analyzed from experimental and numerical results.

Anti-Jamming and Time Delay Performance Analysis of Future SATURN Upgraded Military Aerial Communication Tactical Systems

  • Yang, Taeho;Lee, Kwangyull;Han, Chulhee;An, Kyeongsoo;Jang, Indong;Ahn, Seungbeom
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.9
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    • pp.3029-3042
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    • 2022
  • For over half a century, the United States (US) and its coalition military aircrafts have been using Ultra High Frequency (UHF) band analog modulation (AM) radios in ground-to-air communication and short-range air-to-air communications. Evolving from this, since 2007, the US military and the North Atlantic Treaty Organization (NATO) adopted HAVE QUICK to be used by almost all aircrafts, because it had been revealed that intercepting and jamming of former aircraft communication signals was possible, which placed a serious threat to defense systems. The second-generation Anti-jam Tactical UHF Radio for NATO (SATURN) was developed to replace HAVE QUICK systems by 2023. The NATO Standardization Agreement (STANAG) 4372 is a classified document that defines the SATURN technical and operational specifications. In preparation of this future upgrade to SATURN systems, in this paper, the SATURN technical and operational specifications are reviewed, and the network synchronization, frequency hopping, and communication setup parameters that are controlled by the Network (NET) Time, Time Of Day (TOD), Word Of Day (WOD), and Multiple Word of Day (MWOD) are described in addition to SATURN Edition 3 (ED3) and future Edition 4 (ED4) basic features. In addition, an anti-jamming performance analysis (in reference to partial band jamming and pulse jamming) and the time delay queueing model analysis are conducted based on a SATURN transmitter and receiver assumed model.

Numerical Study and Thrust Prediction of Pintle-Controlled Nozzle with Split-line TVC System (스플릿라인 TVC 시스템을 적용한 핀틀 추력조절 노즐의 유동해석 및 추력 성능 예측)

  • Jo, Hana
    • Journal of the Korean Society of Propulsion Engineers
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    • v.26 no.3
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    • pp.43-53
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    • 2022
  • In this study, analysis of the flow characteristics of pintle-controlled nozzle with split-line TVC system and the thrust performance prediction was performed. The numerical computation was verified by comparing the thrust coefficient derived from the analysis results with the experimental data. By applying the same numerical analysis technique, the flow characteristics of nozzle were confirmed according to operating altitude, pintle stroke position and TVC angle with the 1/10 scale. As the TVC angle increased, thrust loss occurred and the tendency of AF was different depending on the position of the pintle stroke. Based on the analysis results, the relation of thrust coefficient was derived by applying the response surface methods. The thrust performance model with a slight difference of 1.2% on average from the analysis result was generated.

A Study on the Wind Tunnel Facility Performance Improvement of ADD Ludwieg Tube (국방과학연구소 Ludwieg Tube 풍동설비 성능개량 연구)

  • Sangjun Ma
    • Journal of Aerospace System Engineering
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    • v.17 no.4
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    • pp.118-125
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    • 2023
  • The wind tunnel test is one of the essential processes in the development of guided missile systems, and various wind tunnel facilities exist depending on the test requirements, various conditions, and their purposes. The Ludwieg tube is very useful in the development of guided missile systems, and we have necessitated the upgrade of the Ludwieg tube in ADD to acquire various test requirements, such as high angle of attack, repeatability, and stability. In this paper, upgrading the nozzle, vacuum tank, and model support is suggested to improve the Ludwieg tube performance, and we demonstrate a result of the solution through pressure measurement.

Performance Analysis of Real-time Orbit Determination and Prediction for Navigation Message of Regional Navigation Satellite System

  • Jaeuk Park;Bu-Gyeom Kim;Changdon Kee;Donguk Kim
    • Journal of Positioning, Navigation, and Timing
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    • v.12 no.2
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    • pp.167-176
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    • 2023
  • This study presents the performance analysis of real-time orbit determination and prediction for navigation message generation of Regional Navigation Satellite System (RNSS). Since the accuracy of ephemeris and clock correction in navigation message affects the positioning accuracy of the user, it is essential to construct a ground segment that can generate this information precisely when designing a new navigation satellite system. Based on a real-time architecture by an extended Kalman filter, we simulated orbit determination and prediction of RNSS satellites in order to assess the accuracy of orbit and clock prediction and signal-in-space ranging errors (SISRE). As a result of the simulation, the orbit and clock accuracy was at 0.5 m and 2 m levels for 24 hour determination and six hour prediction after the determination, respectively. From the prediction result, we verified that the SISRE of RNSS for six hour prediction was at a 1 m level.

Development of Radar HILS System and Verification Radar Performance Scenario-based (레이다 비행 모의 장치 개발 및 시험 시나리오 기반 레이다 성능 검증)

  • Yong-kil Kwak
    • Journal of Advanced Navigation Technology
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    • v.27 no.5
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    • pp.574-579
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    • 2023
  • The radar flight test has many restrictions on simulating various targets, clutter and jamming signal. Therefore, in this study, a radar HILS system that performs a radar operation simulation function according to an operation scenario was developed. Radar HILS simulates the radar mission environment through radar beam operation simulation, radar operation control, simulated signal generation, and flight attitude simulation.. HILS generates and modulates simulated target signals(single, multiple targets) containing radar mission environments(clutter, jamming etc.) based on flight scenarios, and transmits them to AESA radar over RF. And Scenario-based radar performance was verified by detecting simulated targets and confirming detection results.

Fabrication and Evaluation of Spectroscopic Grade Quasi-hemispherical CdZnTe Detector

  • Beomjun Park;Kyungeun Jung;Changsoo Kim
    • Journal of Radiation Protection and Research
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    • v.49 no.2
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    • pp.85-90
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    • 2024
  • Background: This study focuses on the fabrication and characterization of quasi-hemispherical Cd0.9Zn0.1Te (CZT) detector for gamma-ray spectroscopy applications, aiming to contribute to advancements in radiation measurement and research. Materials and Methods: A CZT ingot was grown using the vertical Bridgman technique, followed by proper fabrication processes including wafering, polishing, chemical etching, electrode deposition, and passivation. Response properties were evaluated under various external bias voltages using gamma-ray sources such as Co-57, Ba-133, and Cs-137. Results and Discussion: The fabricated quasi-hemispherical CZT detector demonstrated sufficient response properties across a wide range of gamma-ray energies, with sufficient energy resolution and peak distinguishability. Higher external bias voltages led to improved performance in terms of energy resolution and peak shape. However, further improvements in defect properties are necessary to enhance detector performance under low bias conditions. Conclusion: This study underscores the efficacy of quasi-hemispherical CZT detector for gamma-ray spectroscopy, providing valuable insights for enhancing their capabilities in radiation research field.