• Journal of Korea Multimedia Society
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• v.22 no.3
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• pp.357-365
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• 2019

In this paper, we suggest the tracking method of moving multi-objects in maritime environments. The image acquisition is conducted using IR(InfraRed) camera sensors on an airborne platform. Under the circumstance of maritime, the qualities of IR images can be significantly degraded due to the clutter influence, which directly gives rise to a tracking loss problem. In order to reduce the effects from the clutters, we introduce a technical approach under Man-In-The-Loop(MITL) system for enhancing the tracking performance. To demonstrate the robustness of the proposed approach based on VTG(Valid Tracking Gate), the simulations are conducted utilizing the airborne IR video sequences: Then, the tracking performances are compared with the existing Kalman Filter tracking techniques.

• International journal of advanced smart convergence
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• v.10 no.3
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• pp.163-171
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• 2021

Recently, Machine Learning-based visualization approaches have been proposed to combat the problem of malware detection. Unfortunately, these techniques are exposed to Adversarial examples. Adversarial examples are noises which can deceive the deep learning based malware detection network such that the malware becomes unrecognizable. To address the shortcomings of these approaches, we present Block-matching and 3D filtering (BM3D) algorithm and deep image prior based denoising technique to defend against adversarial examples on visualization-based malware detection systems. The BM3D based denoising method eliminates most of the adversarial noise. After that the deep image prior based denoising removes the remaining subtle noise. Experimental results on the MS BIG malware dataset and benign samples show that the proposed denoising based defense recovers the performance of the adversarial attacked CNN model for malware detection to some extent.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.4
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• pp.449-456
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• 2021

Impatience characteristics are an important factor to be considered in the defense field, which is sensitive to time, but there are not many cases applied. In addition, due to the difficulty of analysis that must consider various probabilistic factors (breakdown/maintenance distribution, impatience characteristics, etc.), military decision makers consider only simple data (number of occurrences per year, maintenance time, etc.) Therefore, in this study, a model capable of analyzing the performance of the emergency maintenance system for determining the appropriate size and organization of military and civilian maintenance personnel was presented in consideration of impatience characteristics and probabilistic factors. And through numerical analysis, the appropriate size of the military and civilian emergency maintenance teams was analyzed. This study is significant in that it can improve readiness of operational power and prevent waste of defense budget through efficient operation of the military's emergency maintenance system.

• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.22-30
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• 2021

Ventilated cavity shapes by varying angle of attack of a circular cavitator were predicted based on Logvinovich's Independence Principle in order to verify the cavity shape prediction method. The prediction results were compared with model experiments conducted in the high-speed cavitation tunnel. In the prediction of the cavity centerline, the movement of the cavity centerline due to the effect of gravity and cavitator's angle of attack were well predicted. In the prediction of the cavity contour, it was found that the cavity edge prediction error increased as the angle of attack increased. The error of the upper cavity contour was small at the positive angle of attack, and the error of the lower cavity contour was small at the negative angle of attack.

• Annual Conference of KIPS
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• 2024.05a
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• pp.786-787
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• 2024

Large Language Model은 그 기능으로 말미암아 여러 애플리케이션에 통합되고 있다. 특히 OpenAI는 ChatGPT에 여러 세부 사항을 설정함으로써 차별화된 기능을 사용자가 제공할 수 있도록 한다. 하지만 최근 제시되는 프롬프트 연출 공격은 서비스의 핵심 요소를 쉽게 탈취할 수 있는 가능성을 제시한다. 본 연구는 지침 우회 방법론을 통해 기본 대비 공격의 성공률을 10%p 올렸다. 또한 유출공격을 평가할 수 있는 유효성과 성공률을 통해 모델의 방어 성능을 일반화한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.599-604
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• 2018

For missile systems, sustaining high reliability and ensuring economical maintenance are very important. In the Republic of Korea, for most missiles, periodic inspection is mandatory for missiles in the field. Every fixed number of years, they are returned to the ordnance depot to be tested and repaired if faults are found. Almost all missiles have a built-in test (BIT) capability. With the BIT, faulty missiles can be isolated anytime during operations or storage in the launchers. So the reliability and the maintenance costs of the missiles greatly depend on the length of the inspection cycle and the BIT/inspection quality. In this paper, we suggest a model for predicting the storage reliability of missiles subjected to non-periodic tests and periodic inspections, excluding overlapping failures. Some numerical examples are given. This model will be useful for determining the length of the periodic inspection cycle.

• Journal of the Korean Magnetics Society
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• v.20 no.3
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• pp.100-105
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• 2010

For predicting magnetic signals due to the remanent magnetization distributed on a ferromagnetic ship hull, this paper presents an efficient methodology for solving inverse problems, where the material sensitivity analysis based on the continuum mechanics is combined with the equivalent magnetic models. To achieve this, the 3D magnetic charge model and the magnetic dipole moment model are introduced and material sensitivity formulae applicable to each equivalent model are derived. The formulae offer the first-order gradient information of an objective function with respect to the variation of the magnetic charge or magnetic dipole and so an optimal solution can be easily obtained regardless of the number of design variables. To validate the proposed method, the numerical results are comparison with the real measurements of a mock-up model.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.200-206
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• 2008

To implement a mobile radio system, wave-propagation models are necessary to determine propagation characteristics accurately, Currently, the empirical/theoretical prediction models for urban environments are fairly well-developed. But there is a lack of a suitable prediction model for mountain region. So in this paper, to develop the prediction model for mountain region, propagation environments are classified based on three basic mechanisms: reflection, diffraction, penetration(absorbtion and scattering), and measurements have been performed for the classified mountain regions including open area, forest and ridge. Using the measurement data, empirical modeling of propagation characteristics are performed, and then a prediction model for mountain region is proposed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.4
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• pp.629-635
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• 2017

Free-Flooded Ring (FFR) transducer array for use in Sonar system can be driven with large amplitude in a wide frequency band due to its structural characteristics, in which two resonances of a ring mode (1st radial mode) and an inner cavity vibration mode occur in a low frequency band. Since its sound wave generation characteristics are not influenced by the water pressure, the FFR transducer array is widely used in the deep sea. So FFR has been recognized as a low-frequency active sound source and has received much attention ever since. In order to utilize the FFR transducer array for SONAR systems in military and industrial applications, its equivalent electric circuit model is necessary especially to design the matching circuit between the driving power amplifier and the FFR transducer array. Thus this paper proposes the equivalent electric circuit model of FFR transducer array by using measured values of parameter, and suggest the improved method of parameter identification. Finally it verifies the effectiveness of the proposed circuit model of FFR transducer array by experimental measurements.

• Journal of Information Technology and Architecture
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• v.9 no.2
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• pp.167-176
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• 2012

In Korean military measuring systems interoperability is based on LISI (Level of Information System Interoperability) model at the requirement generation and acquisition process. However, LISI model cannot be used for interoperability measurement of system of systems (SoS) because LISI model is focused on interoperability measurement of a given system or system pair. Also, LISI model cannot provide quantitative information for interoperability decision because of qualitative rather than quantitative approach. This paper proposes a quantitative interoperability measurement methodology of SoS. At the proposed methodology, mission threads and supporting systems are identified using architecture approach, and Interoperability of SoS is measured with systems multiplicity and resemblance coefficient. Finally, a case study is presented to show the usefulness of the methodology.