• The Journal of the Acoustical Society of Korea
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• v.40 no.4
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• pp.330-336
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• 2021

In bistatic sonar operation, the scattering strength of a sonar target is characterized by the probe signal frequency, the aspect angle and the bistatic angle. Therefore, the target detection and identification performance of the bistatic sonar may vary depending on how the positions of the target, sound source, and receiver are changed during sonar operation. In this study, it was evaluated which variable is advantageous to change by comparing the target identification performance between the case of changing the aspect angle and the case of changing the bistatic angle during the operation. A scenario of identifying a hollow sphere and a cylinder was assumed, and performance was compared by classifying two targets with a support vector machine and comparing their accuracy using a finite element method-based acoustic scattering simulation. As a result of comparison, using the scattering strength defined by the frequency and the bistatic angle with the aspect angle fixed showed superior average classification accuracy. It means that moving the receiver to change the bistatic angle is more effective than moving the sound source to change the aspect angle for target identification.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2007.11a
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• pp.288-293
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• 2007

미국 911 테러 발생 이후로, 국가 기반시설(예: 송/배전 전력망, 석유/가스 파이프라인, 원자력 발전소, 정보통신 시설, 교통 시설, 금융 시설, 매스미디어 시설 등)에 대한 테러리스트의 사보타지 리스크를 관리하는 도전문제에 정부 차원이나, 기업 차원에서 국내외적으로 뜨거운 이목이 집중되고 있다. 그 가운데 에너지 시스템, 특히 원자력 발전소의 물리적 보안은 국가 안보 차원에서 매우 중대한 이슈가 되고 있다. 이는 사보타지로 인한 이러한 시스템의 파손이 국민, 작업자, 또는 외부 환경에 방사성물질 누출과 같은 중대한 결말을 초래할 수 있기 때문이다. 원전과 같은 복잡 시스템에서 설계 기준 위협이 초래할 수 있는 이러한 결말은 그 시스템의 특정 핵심 표적(예: 부품, 구역, 자산, 행위, 인원)의 방호를 통해 효과적으로 방어될 수 있다. 다시 말하면, 표적 인식에서는 어떻게 방어할 것인가에 앞서서 무엇을 방어할 것인가를 다루려는 것이다. 이 연구의 주요 목적은 여태까지 개발된 다양한 표적 인식 기법의 개발 추세를 소개하고 향후 전망을 제시하는 데에 있다. 이를 통해 표적 인식 기법의 수월성, 신뢰성, 및 경제성을 제고할 수 있으리라 본다. 표적 인식 기술의 활용성 측면에서 볼 때, 표적 인식은 하드웨어 적이거나 소프트웨어적인 방호 시스템의 설계에 필수적이므로, 신뢰성 높은 표적 인식은 다음과 같은 긍정적인 파급 효과를 줄일 수 있다: 1) 사보타지 리스크 감소에 직간접적으로 기여할 수 있다; 2) 제한적인 보안 재원을 효율적으로 할당할 수 있다; 3) 보안 대응군대의 훈련 시나리오를 개발할 수 있다; 4) 발전소 규제요건인 안전조치 계획을 비용이나 보안 측면에서 향상시켜 국민 안심(public easiness)을 도모할 수 있다. 향후에는 보다 더 광의적인 복잡 시스템 사이에서 상호 연계적인 사보타지에 대한 표적 인식의 기법들이 점검될 필요성이 있다고 본다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.2
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• pp.177-180
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• 2019

To improve the accuracy rate of guided weapons, many studies have been conducted on the accurate detection and identification of targets from sea clutter. Because of the variety and complicated characteristics of both sea-clutter and target signals, an active target recognition technique is required. In this study, we propose an algorithm to distinguish clutter and recognize targets by applying a fractal signature(FS) classifier, which is a fractal dimension, and a high-resolution target image(HRTI) classifier, which applies scene matching to an image formed from a scanned image. Simulation results using the algorithm revealed that the HRTI classifier recognized targets 1 and 2 at a 100 % rate, whereas the FS classifier recognized targets 1 and 2 at rates of 90 % and 93 %, respectively.

• Journal of the Korean Magnetics Society
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• v.6 no.2
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• pp.122-129
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• 1996

Fig. 1에서 보는 바와 같이 수 MeV의 에너지를 가진 입사이온이 고체 시료표면과 충돌했을 때 여러 가지의 상호작용과 과정들이 일어난다. 입사 아온이 표적원자의 원자가전자나 내각전자와 상호작용을 하였을 때 원자를 여기시키거나 이온화시키게 되며 입사 이온이 표적 핵과 매우 가까이 접근했을 때 입사이온과 표적 핵사이에 쿨롱상호작용이나 핵 상호작용이 일어나게 된다. 이러한 여러가지 상호작용의 결과들로부터 분석하고자 하는 시료의 성분, 구조, 상호작용 과정에 대한 정보를 얻을 수 있다. 이러한 고에너지 이온선을 이용한 분석기술로는 Fig. 1에서 보는 바와 같이 후방산란법(BS : Backscattering Spectrometry), 전방산란법(FRS : Forward Recoil Spectrometry), 핵반응법(NRA : Nuclear Reaction Analysis), 양성자여기X선검출법(PIXE : Proton Induced X-ray Emission)등과 이러한 방법들과 같이 조합하여 사용하는 이온 채널링(ion channeling)등이 있다. 본 해설에서는 이러한 분석법중에서도 널리 사용되고 있는 후방산란법과 이온 채널링에 대하여 주로 기술하고자 한다.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.474-481
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• 2017

This paper presents a multiple target tracking system using Normalized Rayleigh likelihood of amplitude information of target. Although many studies of Radar systems using amplitude information have been studied, they are focused on single target tracking. This paper proposes the multiple target tracking using amplitude information as well as kinematic information from Radar sensor. The amplitude information are applied in generating the association probability of joint probabilistic data association(JPDA) algorithm through the normalized Rayleigh likelihood. It is verified that the proposed system can enhance the track maintenance and tracking accuracy, especially, in the target crossing case.

• Defense and Technology
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• no.4 s.290
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• pp.44-53
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• 2003

Hawk에 대한 미래의 계획은, Raytheon/Kongsberg사가 네덜란드 육군 및 공군용으로 개발한 Hawk-AMRAAM 방공시스템의 경우처럼, Raytheon사의 AIM-120 AMRAAM 공대공 미사일을 육상 발사형으로 개조하여 Hawk와 결합시키는 시스템에 초점이 모아지고 있다. AIM-120 미사일은 다수의 고속, 저고도 표적을 요격하기 위해서 사용되며, 사거리는 약 20km이고 최소 발사 간격은 2초 이내이다. 이러한 Hawk/AIM-120 조합을 통해서 Hawk의 장거리 및 고고도 표적에 대한 교전능력을 유지하면서, 작은 레이더 단면적 표적에 대한 Hawk ILM 미사일의 우수한 요격능력도 보유할 수 있게 된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.334-341
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• 2020

The optimum solutions of the instability of the target velocity were studied to solve the case of the target velocity of the ship approaching at a speed of ◯◯knots and deviated by more than ± 10knots, while the surveillance radar rotating speed was varied, while the maximum search range of the radar was evaluated during the operational test & evaluation. The instability of the target velocity did not enable the radar to calculate the information of the target precisely and to degrade the probability of hit and the quality of the target management. The improvement to handle the deviation of the target velocity was optimally determined by using a fishbone diagram to find 9 reasons based on 4M1E, and the algorithm of the target management was identified as the crucial reason. In this study, the improvement was applied to the filter algorithm to stabilize the target velocity in the target tracking management SW by reviewing the current algorithm to find the velocity of the target and recognizing that the problem does not apply to different 𝜶, 𝞫 values when the antenna changed the rotating speed. The ability of the improvement to work was tested on board.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.534-542
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• 2021

Single-molecular guide RNA (sgRNA) plays a role in recognizing the DNA target sequence in CRISPR technology for genome editing and gene expression control. In this study, we systematically compared the length of the target recognition sequence in sgRNAs required for genome editing using Cas9-NG (an engineered Cas9 recognizing 5'-NG as PAM sequence) and gene expression control using deactivated Cas9-NG (dCas9-NG) by targeting the gal promoter in E. coli. In the case of genome editing, the truncation of three nucleotides in the target recognition sequence (TRS) of sgRNA was allowed. In gene expression regulation, we observed that target recognition and binding were possible even if eleven nucleotides were deleted from twenty nucleotides of the TRS. When 4 or more nucleotides are truncated in the TRS of the sgRNA, it is thought that the sgRNA/Cas9-NG complex can specifically bind to the target DNA sequence, but lacks endonuclease activity to perform genome editing. Our study will be helpful in the development of artificial transcription factors and various CRISPR technologies in the field of synthetic biology.

• Journal of the Korea Society of Computer and Information
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• v.19 no.11
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• pp.43-52
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• 2014

In this paper, we propose the target detection method using image displacement, and classification method using SURF(Speeded Up Robust Features) feature points and BAS(Beam Angle Statistics) in infrared images. The SURF method that is a typical correspondence matching method in the area of image processing has been widely used, because it is significantly faster than the SIFT(Scale Invariant Feature Transform) method, and produces a similar performance. In addition, in most SURF based object recognition method, it consists of feature point extraction and matching process. In proposed method, it detects the target area using the displacement, and target classification is performed by using the geometry of SURF feature points. The proposed method was applied to the unmanned target detection/recognition system. The experimental results in virtual images and real images, we have approximately 73~85% of the classification performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.4
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• pp.63-73
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• 2021

The radar operated to detect/track aircraft targets is divided into a search radar that operates while the antenna rotating device rotates for the purpose of detecting the target according to the mission characteristics, and a tracking radar that periodically steers and tracks a beam to the predicted position of the target. The tracking radar has a shorter target information acquisition preiod than the search radar. Due to this characteristic, the tracking accuracy is better than that of the search radar, but as the prediction error increases due to the speed error at the beginning of the tracking, there are many cases in which tracking fails at the beginning of tracking due to failure to perform beam steering normally. In this paper, in order to solve the above-mentioned problems, we propose an algorithm for improving the accuracy of track initiation using radial velocity measurements in addition to the position of the measured, and confirm the performance of the proposed algorithm by comparing with the two point differential algorithm