• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.357-358
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• 2018

The track radar use the range track loop to track the target range. The bandwidth of the radar range tracker can be determined by tradeoff according to signal to noise ratio and the target range. On the other hand, electronic warfare is carried out to prevent the radar from tracking targets by electronic attack. The deception or noise jamming in electronic warfare can be performed to interfere with the range track loop of the radar. In order to efficiently perform electronic warfare, the bandwidth in radar tracking loop is estimated and can be used for electronic attack. To do this, we have studied the method of estimating the bandwidth of radar tracking loop using the variables that can be gathered in electronic warfare.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.4
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• pp.112-123
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• 2017

Research for the inverse estimation of RF threats and the efficient electronic attack based on the parameters of the electronic information has been active in the electronic warfare (EW) situations. In this paper, an EW transmission simulator is constructed from the modeling of radar threats, EW receivers, and propagation environments with the collected electronic information in order to verify the performance of the inverse estimation algorithm in various and practical EW situations. In simulation results, we show that the range tracking error and angle tracking error are produced within ten meters and one degree, respectively. And also, we show that the changing relations between the angle tracking error and the parameters of the monopulse angle tracking radar such as the beamwidth and squint angle in simulation results correspond with those in the theoretical modeling. Accordingly, the constructed EW simulator can be used to observe the modifying characteristics of the electronic information in transmission environments, and then, to evaluate the performance of the inverse estimation system in various EW situations.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.4
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• pp.73-85
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• 2010

In dense electronic warfare signal environments, the conventional radar identification methods based on the basic parameters such as frequency, pulse width, and pulse repetition interval are confronted by the problem of identification ambiguity. To overcome this critical problem, a new approach introducing scan pattern of radars has been presented. Researches on new identification methods, however, suffer from a practical problem that it is not easy to secure the many radar signals including various scan pattern information and operation parameters. This paper presents a modeling method of radar signals with which we can generate radar signals including various scan pattern types according to the parameters determining the variation pattern of received signal strength. In addition, with the radar signals generated by the proposed model we analyze their characteristics according to the location of an electronic warfare support (ES) system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.1986-1995
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• 2013

The ELINT system which derives intelligence from electromagnetic radiations plays an important role in modern electric warfares. Among radar characteristics inferred from the signals, intra-pulse modulation scheme is a useful feature to identify modern radars. This paper proposes the method to classify intra-pulse modulation schemes such as UM, PSK, BFSK, QFSK, LFM and NLFM based on the fuzzy algorithm. The proposed method defines fuzzy membership functions to characterize input signals, and then it calculates accordance rates for each modulation scheme with fuzzy inference rules. The experimental results show that the probability of correct recognition is more than 95% for SNR > 10dB.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.1
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• pp.76-86
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• 1996

복식사 연구의 한 방법으로서, 문헌을 통하여 다량의 정보 수집이 가능할 경우, 사회과학의 분야에서 사용되어 온 내용분석법을 도입하여 정보의 수량화를 꾀할 수 있다. 본 연구에서는 내용분석법을 이용하여 1856년부터 1870년에 이르기까지 미국 여성의 평상복(daydress)중 재킷과 치마의 유행 경향을 당시의 대포적인 패션 잡지인 Godey's Ladies Book과 Perterson's Magazine의 패션 삽화를 토대로 분석하였다. 1856∼1870년은 미국의 남북전쟁 발발 5년 전부터 남북전쟁 직후 5년까지 의 15년간의 기간을 이르며, 해당 15년은 전쟁 전, 전쟁 중, 그리고 전쟁 후의 5년간씩의 3 시기로 나뉘어졌다. 연구의 목적은 여성 평상복의 디자인이 위의 기간 동안 남북전쟁의 한 영향으로서 군복 '라일의 경향을 띄게 되는지의 여부를 조사하는 것이다. 군복 스타일의 경향은 몸에 꼭 맞는 실루엣(fitted silhouette), 에플렛(epaulet), 스텐딩 칼라(standing collar), 더블 여밈 (double-breastedness) 다수의 단추의 사용 및 장식(buttons)으로 정의되었다. 여성스러운 스타일의 경향은 풍성한 실루엣 (full silhouette), 플라운스가 된 치마(flounced skirt), 그리고 러플/fp이 스/리본 (ruffles/lace/ribbons)의 사용 여부로 정의되었다. 연구의 초점은 객관적이고 체계적인 문헌 정보의 수집 방법을 수립하는 데 있었으며, 수집된 자로는 각 변수의 빈도 분포포에 의해 조사되었다. Fitted silhouette, epaulet, 그리고 standing collar는 제 3시기에 가장 많이 나타났고 제 1시기에 가장 적게 나타났다. 여성스러운 스타일에 있어서 full sihouette과 trounced skirt는 제 1시기에 가 장 많이 보였고 전쟁 당시와 전후에 점차적으로 적게 나타났다. Buttons나 double breastedness 등은 제 2시기에 가장 많이 보이고 제 3시기에는 오히려 가장 낮은 빈도수를 보였다. 반면에 ruffles/lace/ribbons는 fitted silhouette 등의 군복 스타일의 변수와 더불어 제 3시기에 가장 많이 보인 것으로 분석되었다. 전반적인 유행의 경향에 있어서, 군복 스타일의 변수와 여성스러운 경향의 변수를 각각 종합하여 분석해 보면, 제 2시기를 중심으로 전자의 유행은 점차적으로 증가하고 후자의 유행은 감소되고 있는 것을 볼 수 있다. 그러나 당시 미국 패션은 유럽 왕실의 유행에 의해 크게 영향을 받은 것을 감안할 때 본 연구의 결괴는 서양 복식의 역사의 선상에서 조심스럽게 해석되어야 할 것 이다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.165-166
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• 2007

신경망을 이용하여 반구형 유도결합형 플라즈마 장비에 대한 전자온도의 예측모델을 개발하였다. 신경망으로는 Radial Basis Function Network을 이용하였고, 신경망의 예측성능은 유전자 알고리즘을 이용하여 최적화하였다. 체계적인 모델링을 위해 $2^4$ 전 인자 (Full Factorial) 실험획법을 이용하여 $Cl_2$ 플라즈마에서의 데이터를 수집하였다. 최적화된 전자온도 모델의 예측성능은 0.143 eV이었다. 개발된 모델을 이용하여 공정변수에 따른 예측온도의 영향을 고찰하였다. 소스전력과 압력의 변화에 따른 전자온도의 변화는 작았다. 그러나 $Cl_2$ 유량과 특히 척위치의 증가에 따른 전자온도의 증가는 현저하였으며, 이는 고이온밀도의 형성에 기인하는 것으로 해석되었다.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.4
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• pp.29-39
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• 2017

Various electronic warfare situations drive the need to develop an integrated electronic warfare simulator that can perform electronic warfare modeling and simulation on radar threats. In this paper, we analyze the components of a simulation system to reversely model the radar threats that emit electromagnetic signals based on the parameters of the electronic information, and propose a method to gradually maintain the reverse extrapolation model of RF threats. In the experiment, we will evaluate the effectiveness of the incremental model update and also assess the integration method of reverse extrapolation models. The individual model of RF threats are constructed by using decision tree, naive Bayesian classifier, artificial neural network, and clustering algorithms through Euclidean distance and cosine similarity measurement, respectively. Experimental results show that the accuracy of reverse extrapolation models improves, while the size of the threat sample increases. In addition, we use voting, weighted voting, and the Dempster-Shafer algorithm to integrate the results of the five different models of RF threats. As a result, the final decision of reverse extrapolation through the Dempster-Shafer algorithm shows the best performance in its accuracy.

• Information Systems Review
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• v.25 no.4
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• pp.183-204
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• 2023

Due to the COVID-19 pandemic, lots of occasions need to be held in online environment. This is the reason why "Metaverse" gets lots of attention in 2021. A number of companies made announcements on Metaverse, and this situation also boomed stock market. This paper investigates the relationship between Metaverse initiatives and business value of the firm (i.e., stock prices). We examine this relationship by using event study method with Lexis-Nexis News data from 2019 to 2021. The results indicate that Metaverse initiatives significantly impact positive influence on firm's value. In the technological perspective, technical factors affect more positive market returns, including Metaverse enablers (e.g., NFT, VR devices, digital twin) and common infrastructure (e.g., semiconductor, AI, cloud), and especially virtual environment was emphasized. Additionally, in the strategical perspective, radical innovation (e.g., pivoting, acquisition) impact more positive market return rather than incremental innovation (e.g., partnership, investment). Also, firms from non-service industries can achieve benefits from Metaverse initiatives rather than service industry in some degree.