• 대한임베디드공학회논문지
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• 제9권5호
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• pp.269-276
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• 2014

In recent, autonomous navigation techniques to avoid obstacles have been studied by using unmanned aircraft vehicles(UAVs) since the increment of UAV's interest and utilization. Particularly, autonomous navigation based UAVs are utilized in several areas such as military, police, media, and so on. However, there are still some problems to avoid obstacle when UVAs perform autonomous navigation. For instance, the UAV can not forward in the corner of corridors even though it utilizes the improved vanish point algorithm that makes an autonomous navigation system. Therefore, in this paper, we propose an obstacle avoidance technique based on immune algorithm for autonomous navigation of Quadrotor. The proposed algorithm is consisted of two steps such as 1) single color discrimination and 2) multiple color discrimination. According to the result of experiments, we can solve the previous problem of the improved vanish point algorithm and improve the performance of autonomous navigation of Quadrotor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1954-1956
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• 2004

Nowadays, $CO_2$ lasers are used widely in many applications such as materials fabrication, communications, remote sensing and military purpose etc. Especially, $CO_2$ lasers are in the spotlight at surface handling and heat processing. It is important to control the laser output power and beam Quality in those fields. And those are studied the important parameters deciding the fluctuation of laser beam are smoothing capacitor, frequency and the characteristics of laser resonator. But the study of plasma parameters of $CO_2$ lasers are little. So we detect the $CO_2$ laser from emitted $CO_2$ laser discharge plasma using a non-contact photo tansistor sensor and Low pass filter. In this study, The relativity of the emitted light of discharge plasma and CO2 laser output.

• 항공우주기술
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• 제13권1호
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• pp.166-173
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• 2014

최근 쿼드콥터에 대한 관심이 증가하면서 방송에서 군에 이르기까지 다양한 분야에서 활용되고 있다. 특히 다수의 쿼드콥터를 동시에 제어하는 군집 비행 연구는 중요 임무 수행 성공 확률을 높일 수 있고, 예술과 융합되어 군무를 수행하는 등 다양한 응용에 활용될 수 있다. 본 논문에서는 AR.Drone을 활용하여 실내에서 모션 캡쳐 기반으로 다수의 비행체가 서로의 위치를 파악하고, 시나리오에 맞춰 정해진 임무를 수행하기 위해 개발된 군집 비행 시스템을 소개한다.

• 실천공학교육논문지
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• 제5권2호
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• pp.117-122
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• 2013

첨단 IT 기술이 발달함에 따라 가상현실 기술이 빠르게 발달하고 있으며, 각 분야에서 가상현실 기술을 이용한 연구가 활발히 진행되고 있다. 가상현실을 활용한 분야로는 교육, 군사, 의료, 예술, 오락 등, 다양한 분야에서 연구가 진행되고 있다. 본 연구에서는 가상현실기술을 기술교육분야에 적용하여 다양한 형태의 가상훈련 콘텐츠를 개발하였으며 개발된 가상훈련 콘텐츠들을 유형별 분류하고 그 특징과 효과를 비교하고 분석하였다. 또한 가상훈련 콘텐츠를 기술교육에 실제 활용한 사례를 유형별로 조사하여 가상훈련 콘텐츠의 교육적 효과를 확인하였다.

• International Journal of Internet, Broadcasting and Communication
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• 제12권3호
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• pp.156-162
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• 2020

Wireless Sensor Network (WSN) field is mainly studied to monitor and characterize large-scale physical environments to track various environmental or physical conditions, such as temperature, pressure, wind speed and humidity. WSN can be used in various applications such as wild surveillance, military target tracking and monitoring, dangerous environmental exploration and natural disaster relief. We design probabilistic mobile models that apply to mobile ad hoc network mobile environments. A probabilistic shift model proposed by dividing the number of moving nodes and the distance of travel into two categories to express node movement characteristics. The proposed model of movement through simulation was compared with the existing random movement model, ensuring that the width and variation rate of the first node node node node (FND) was stable regardless of the node movement rate. In addition, when the proposed mobile model is applied to the routing protocol, the superiority of network life can be verified from measured FND values. We overcame the limitations of the existing random movement model, showing excellent characteristics in terms of energy efficiency and stable in terms of changes in node movement.

• 한국멀티미디어학회논문지
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• 제21권5호
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• pp.545-557
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• 2018

The Global Positioning System (GPS) has become popular and widely used in many fields from military to civilian applications. However, GPS signals are suffered from interference due to its weak signal over wireless channel. There are many types of interference, such as jamming, blocking multipath, and spoofing, which can mislead the operation of GPS receiver. In this paper, vector-based tracking loop model with integrity check is proposed to detect and mitigate the harmful effect of interference on GPS receiver operation. The suggested methods are implemented in the tracking loop of GPS receiver. As a first method, integrity check with carrier-to-noise ratio (C/No) monitoring technique is applied to detect the presence of interference and prevent contaminated channels out of tracking channels to calculate position. As a second method, a vector-based tracking loop using Extended Kalman Filter with adaptive noise covariance according to C/No monitoring results. The proposed methods have been implemented on simulated dataset. The results demonstrates that the suggested methods significantly mitigate interference of Additive White Gaussian Noise (AWGN) and improve position calculation by 44%.

• 한국측량학회지
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• 제35권4호
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• pp.319-326
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• 2017

SAR (Synthetic aperture radar) images are less affected by the weather compared to optical images and can be obtained at any time of the day. Therefore, SAR images are being actively utilized for military applications and natural disasters. However, because SAR data are in grayscale, it is difficult to perform visual analysis and to decipher details. In this study, we propose a color mapping method using RF (random forest) regression for enhancing the visual decipherability of SAR images. COSMO-SkyMed 2 and WorldView-3 images were obtained for the same area and RF regression was used to establish color configurations for performing color mapping. The results were compared with image fusion, a traditional color mapping method. The UIQI (universal image quality index), the SSIM (structural similarity) index, and CC (correlation coefficients) were used to evaluate the image quality. The color-mapped image based on the RF regression had a significantly higher quality than the images derived from the other methods. From the experimental result, the use of color mapping based on the RF regression for SAR images was confirmed.

• 한국전기전자재료학회논문지
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• 제30권9호
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• pp.583-588
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• 2017

Thermal batteries are used in military power sources that require robustness and long storage life for applications in missiles and torpedoes. $FeS_2$ powder is currently used as a cathode material because of its high specific energy density, environmental non-toxicity, and low cost. $MS_2$ (M = Fe, Ni, Co) cathodes have been explored as novel candidates for thermal batteries in many studies; however, the discharge characteristics (1, 2, 3 plateau) of single cells in thermal batteries with different cathodes have not been elucidated in detail. In this study, we independently analyzed the discharge voltage and calculated the total polarizations of single cells using $MS_2$ cathodes. Based on the results of this study, we propose $NiS_2$ as a potential cathode material for use in thermal batteries.

• Advances in materials Research
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• 제3권4호
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• pp.233-242
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• 2014

Magnetic and conducting aniline sulfide resin cross-linked (ASC-Fe3O4) nanocomposite has been prepared in the presence of aniline sulfide resin (ASR), aniline, $Fe_3O_4$ coated by polyethylene glycol (PEG) and initiator. The magnetic properties of the resulting composites showed ferromagnetic behavior, such as high-saturated magnetization (Ms= 41 emu/g), and coercive force (Hc=1.5 Oe). The saturated magnetization was increased by increasing of $Fe_3O_4$ content and decreased by increasing aniline ratio. The transmission electron micrograph (TEM) and X-ray diffraction proved that nanometer-sized about 20-30 nm $Fe_3O_4$ in the composite. The average size of ASC-$Fe_3O_4$ nanocomposite with core-shell structure was about 50-60 nm, and polydisperse. This approach may also be extended to the synthesis and modification of other polymers. Electrical conductivity of aniline sulfide resin cross-linked (ASC) nanocomposite has been studied by four-point probe method and produced $3.3{\times}10^{-4}S/cm$ conductivity for it. The conductivity of the composites at room temperature depended on the $Fe_3O_4$, aniline ratio and doping degree. The thermogravimetry analysis (TGA) results showed that this resin is thermal resistance near of $500^{\circ}C$. So, It can be used for resistance thermal coating for military applications. $Fe_3O_4$-PASC nanocomposite has been flexible structure with electrical and magnetic properties.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권3호
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• pp.901-920
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• 2015

Wireless Sensor Networks (WSNs) are widely used in geographically isolated applications like military border area monitoring, battle field surveillance, forest fire detection systems, etc. Uninterrupted power supply is not possible in isolated locations and hence sensor nodes live on their own battery power. Localization of sensor nodes in isolated locations is important to identify the location of event for further actions. Existing localization algorithms consume more energy at sensor nodes for computation and communication thereby reduce the lifetime of entire WSNs. Existing approaches also suffer with less localization coverage and localization accuracy. The objective of the proposed work is to increase the lifetime of WSNs while increasing the localization coverage and localization accuracy. A novel intelligent unmanned aerial vehicle anchor node (IUAN) is proposed to reduce the communication cost at sensor nodes during localization. Further, the localization computation cost is reduced at each sensor node by the proposed intelligent arc selection (IAS) algorithm. IUANs construct the location-distance messages (LDMs) for sensor nodes deployed in isolated locations and reach the Control Station (CS). Further, the CS aggregates the LDMs from different IUANs and computes the position of sensor nodes using IAS algorithm. The life time of WSN is analyzed in this paper to prove the efficiency of the proposed localization approach. The proposed localization approach considerably extends the lifetime of WSNs, localization coverage and localization accuracy in isolated environments.