• Title/Summary/Keyword: Defence Science and Technology

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Research of Interopaeration Simulation between War Game Simulator and Communication Effect Simulator using HLA/RTI (HLA/RTI를 이용한 워게임 시뮬레이터와 통신 효과 시뮬레이터의 연동 시뮬레이션 연구)

  • Kim, Deok-Su;Bae, Jang Won;Park, Soo Bum;Kim, Tag Gon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.18 no.1
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    • pp.46-54
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    • 2015
  • Wargame simulators are widely used in the field of defence modeling and simulation. Because of increasing importance of communication effects on the warfare, the war game simulator is also required to reflect communication effects. One way to satisfy the requirement is the interoperation simulation between war game simulator and communication effect simulators. This paper shows the application of interoperation simulation between war game and communication effect simulators using HLA(High-Level Architecture)/RTI(RunTime Infrastructure). The war game simulator mainly deal with the engagement of troops and the troops communicate each other at the mission execution level. In the other hand, The communication effect simulator perform communication actions between the troops in the engineering level. Using the interoperation simulation, we can reflect the communication effects on the war game simulation. We show various applications of the interoperation simulation with the point of the war game and communication effect simulator. with a case study, we explain the interoperation simulation improves the reality and fidelity of the war game simulator and how the interoperation simulation can be applied to developing doctrines and real communication system.

Exploring the Potentiality of Novel Rhizospheric Bacterial Strains against the Rice Blast Fungus Magnaporthe oryzae

  • Amruta, Narayanappa;Kumar, M.K. Prasanna;Puneeth, M.E.;Sarika, Gowdiperu;Kandikattu, Hemanth Kumar;Vishwanath, K.;Narayanaswamy, Sonnappa
    • The Plant Pathology Journal
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    • v.34 no.2
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    • pp.126-138
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    • 2018
  • Rice blast caused by Magnaporthe oryzae is a major disease. In the present study, we aimed to identify and evaluate the novel bacterial isolates from rice rhizosphere for biocontrol of M. oryzae pathogen. Sixty bacterial strains from the rice plant's rhizosphere were tested for their biocontrol activity against M. oryzae under in vitro and in vivo. Among them, B. amyloliquefaciens had significant high activity against the pathogen. The least disease severity and highest germination were recorded in seeds treated with B. amyloliquefaciens UASBR9 (0.96 and 98.00%) compared to untreated control (3.43 and 95.00%, respectively) under in vivo condition. These isolates had high activity of enzymes in relation to growth promoting activity upon challenge inoculation of the pathogen. The potential strains were identified based on 16S rRNA gene sequencing and dominance of these particular genes were associated in Bacillus strains. These strains were also confirmed for the presence of antimicrobial peptide biosynthetic genes viz., srfAA (surfactin), fenD (fengycin), spaS (subtilin), and ituC (iturin) related to secondary metabolite production (e.g., AMPs). Overall, the results suggested that application of potential bacterial strains like B. amyloliquefaciens UASBR9 not only helps in control of the biological suppression of one of the most devastating rice pathogens, M. grisea but also increases plant growth along with a reduction in application of toxic chemical pesticides.

Evaluation of Characteristic for SS400 and STS304 Steel by Weld Thermal Cycle Simulation - 3rd Report: Residual Stress and Ultrasonic Parameter (용접열사이클 재현에 의한 SS400강 및 STS304강의 특성 평가 - 제3보: 잔류응력과 초음파 파라미터)

  • Ahn, Seok-Hwan;Choi, Moon-Oh;Jeong, Jeong-Hwan;Kim, Sung-Kwang;Nam, Ki-Woo
    • Journal of Ocean Engineering and Technology
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    • v.22 no.6
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    • pp.27-34
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    • 2008
  • The temperature distribution in the weldment is not uniform because a weldment is locally heated. Thermal plastic deformation results from the local expansion and shrinkage by the heating and cooling of metal. Therefore, residual stresses and distortion occur in the weldment. In this study, we had conducted on the weld thermal cycle simulation that is supposed as the HAZ on SS400 steel and STS304 steel. The residual stresses that were obtained from the drawing and the weld thermal cycle simulation were estimated by X-ray diffraction. We also carried out ultrasonic test for the weld thermal cycle simulated specimens, and then conducted on nondestructive evaluation by the ultrasonic parameters obtained ultrasonic test. From the results, residual stresses of weld thermal cycle simulated specimens after the residual stress removal heat treatment are lower than that of the drawing.

Optimal design of Natural Fiber Composite Structure for Automobile

  • Lee, Haseung;Kong, Changduk;Park, Hyunbum
    • International Journal of Aerospace System Engineering
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    • v.3 no.1
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    • pp.21-24
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    • 2016
  • In this study, a optimal design on the hood automotive using eco-friendly natural fiber composites is performed. The hood of an automobile is determined by dividing the Inner panel shape through optimization phase to outer panel and inner panel. It was performed to optimize the size of the thickness of the inner panel and the outer panel by applying a flax/epoxy composite materials. The optimized shape was evaluated for weight-lightening, stability and the pedestrian collision safety. Through the resin flow analysis are confirmed to molding possibility judgment of product.

An Integrated CAD/CAM System for CNG Pressure Vessel Manufactured by Deep Drawing and Ironing Operation

  • Park, Joon-Hong;Kim, Chul;Park, Jae-Chan
    • Journal of Mechanical Science and Technology
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    • v.18 no.6
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    • pp.904-914
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    • 2004
  • The fiber reinforced composite material is widely used in the multi-industrial field because of their high specific modulus and specific strength. It has two main merits which are to cut down energy by reducing weight and to prevent explosive damage proceeding to the sudden bursting which is generated by the pressure leakage condition. Therefore, Pressure vessels using this composite material can be applied in the field such as defence industry and aerospace industry. In this paper, for nonlinear finite element analysis of E-glass/epoxy filament winding of composite vessel subjected to internal pressure, the standard interpretation model is developed by using the ANSYS with AutoLISP and ANSYS APDL languages, general commercial software, which is verified as useful characteristic of the solution. Among the modules of the system, both the process planning module for carrying out the process planning of filament wound composite pressure vessel and the autofrettage process module for obtaining higher residual stress will minimize trial and error and reduce the period for developing new products. The system can serve as a valuable system for experts and as a dependable training aid for beginners.

Prelinimary Engagement Effect Analysis of Isotropic Kinetic Energy Warhead (등방성 운동에너지 탄두의 교전 효과 예비 분석)

  • Shim, Sang-Wook;Hong, Seong-Min;Seo, Min-Guk;Tahk, Min-Jea
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.43 no.5
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    • pp.440-448
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    • 2015
  • Kinetic energy(KE) rod warhead system is a new interceptor which combines advantages of existing ones. This system is less dependant on a precision guidance than direct hit type warhead and gives high penetration rates than blast fragmentation type warhead. In this paper, isotropic KE rod warhead system is introduced with detonation/deployment model. A penetration effects of the deployed rods are calculated using TATE penetration equation. Also, an engagement performance analysis method is suggested. Finally, an optimal detonation time and engagement geometry is derived by Monte-Carlo simulation in various engagement situation using the performance analysis factor.

ANALYSIS OF OCEAN WAVE BY AIRBORNE PI-SAR X-BAND IMAGES

  • Yang, Chan-Su;Ouchi, Kazuo
    • Proceedings of the KSRS Conference
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    • 2008.10a
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    • pp.240-242
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    • 2008
  • In the present article, we analyze airborne Pi-SAR (Polarimetric-Interferometric SAR) X-band images of ocean waves around the Miyake Island at approximately 180 km south from Tokyo, Japan. Two images of a same scene were produced at approximately 40 min. interval from two directions at right angles. One image shows dominant range travelling waves, but the other image shows a different wave pattern. This difference can be caused by the different image modulations of RCS and velocity bunching. We have estimated the dominant wavelength from the image of range waves, and from the wave phase velocity computed from the dispersion relation (though no wave height data were available), the image intensity is computed by using the velocity bunching model. The comparison of the result with the second image at right angle strongly suggests the evidence of velocity bunching.

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Modeling and simulation on an IR absorbing structure with the cascaded transmission line model (전송선 이론에 의한 적외선 흡수 구조체의 흡수율 모의시험)

  • Park, Seung-Man
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.12
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    • pp.1725-1729
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    • 2013
  • In this paper, the modeling and simulation of infrared absorption in an infrared absorbing structure with the cascaded transmission line model were carried out. Each layer in the infrared absorbing structure can be modeled as a characteristic impedance of the cascaded transmission line model. The simulation results show that the cavity thickness to get a maximum absorption should be less than a quarter wavelength, which is somewhat different from prevalent thickness. It can be assured that the sheet resistance of an absorbing layer to get a maximum absorption is $377{\Omega}/{\square}$, that the thickness of the absorbing layer dose not affect the spectral characteristics of absorption. It is also shown that the thickness of the active layer is not critical to the IR absorption. It can also be assured that the validation of this modeling is proved in comparison with the previous results from similar absorbing structures.

Efficient Recognition Method for Ballistic Warheads by the Fusion of Feature Vectors Based on Flight Phase (비행 단계별 특성벡터 융합을 통한 효과적인 탄두 식별방법)

  • Choi, In-Oh;Kim, Si-Ho;Jung, Joo-Ho;Kim, Kyung-Tae;Park, Sang-Hong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.6
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    • pp.487-497
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    • 2019
  • It is very difficult to detect ballistic missiles because of small cross-sections of the radar and the high maneuverability of the missiles. In addition, it is very difficult to recognize and intercept warheads because of the existence of debris and decoy with similar motion parameters in each flight phase. Therefore, feature vectors based on the maneuver, the micro-motion according to flight phase are needed, and the two types of features must be fused for the efficient recognition of ballistic warhead regardless of the flight phase. In this paper, we introduce feature vectors appropriate for each flight phase and an effective method to fuse them at the feature vector-level and classifier-level. According to the classification simulations using the radar signals predicted by the CAD models, the closer the warhead was to the final destination, the more improved was the classification performance. This was achieved by the classifier-level fusion, regardless of the flight phase in a noisy environment.

Experimental Validation of Multiple UAVs with Vector Field Guidance for SEAD(Suppression of Enemy Air Defense) (벡터필드 유도기법이 적용된 다수 무인기를 이용한 적 방공망 제압 임무의 실험적 검증)

  • Jung, Wooyoung;Kim, Ki-Duck;Lee, Seongheon;Bang, Hyochoong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.43 no.3
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    • pp.282-287
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    • 2015
  • In modern warfare, the importance of SEAD(Suppression of Enemy Air Defense) mission is being emphasized. However, this mission runs the risk of hull damage or casualties of our friendly air forces. Because of these risks, research on the way of minimizing damages and enhancing mission capability is under active discussion. As a part of this research, SEAD mission planning with multiple UAVs has been covered using vector field guidance. This guidance method not only applies to various forms of flight path but also requires less computational power than other guidance methods. Therefore, in this paper, planning methods of SEAD mission for multiple UAVs using vector field guidance and experimental data from flight experiments regarding designed mission has been covered.