• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권1호
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• pp.421-433
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• 2015

Recently, there have been fast-growing social network services based on the Internet environment and web technology development, the prevalence of smartphones, etc. Social networks also allow the users to convey the information and news so that they have a great influence on the public opinion formed by social interaction among users as well as the spread of information. On the other hand, these social networks also serve as perfect environments for rampant malware. Malware is rapidly being spread because relationships are formed on trust among the users. In this paper, an effective patch strategy is proposed to deal with malicious worms based on social networks. A graph is formed to analyze the structure of a social network, and subgroups are formed in the graph for the distributed patch strategy. The weighted directions and activities between the nodes are taken into account to select reliable key nodes from the generated subgroups, and the Incremental PageRanking algorithm reflecting dynamic social network features (addition/deletion of users and links) is used for deriving the high influential key nodes. With the patch based on the derived key nodes, the proposed method can prevent worms from spreading over social networks.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2004년도 추계학술발표논문집(상)
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• pp.833-836
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• 2004

세그먼트 패치(Segment Patch) 기반의 스테레오 매칭에 있어서, 매칭의 속도와 정확도는 세그먼트 패치를 생성하는 과정에 의존한다. 본 논문에서는 매칭 프리미티브로 사용되는 세그먼트 패치를 결정하는 과정으로 영상의 강도와 함께 인접 세그먼트 패치들 사이의 깊이를 고려하여 최적의 세그먼트 패치를 결정하는 방법을 제안하였다. 그 결과 영상의 강도 변화가 작은 영역에서 뿐만 아니라 패치 매칭의 취약함으로 지적되었던 복잡한 영역에서도 좋은 결과를 보여 주었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.265-266
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• 2008

The objective of this paper is to effectively detect partial discharges in XLPE power cables. In this field, we have been usually applied several sensors for such partial discharges. This study used a type of beyond compare antenna based on the influence of background noises. Also, we designed a new structure that is able to easily apply in the adhesion of planar patch types for XLPE power cables in measurement sensitiveness elevation. A high frequency simulation tool (CST-MWS) was applied to the antenna used in this study, and it was used to evaluate certain characteristics. We fabricated an antenna using the simulation data obtained from a specific test. After checking the sensitivity of this Planar Patch Sensor in the Lab, it was tested in an actual site. This paper analyzed the data as a part of time and frequency domain using an oscilloscope and spectrum analyzer, respectively.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.61-62
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• 2017

본 연구에서는 주파수 1.5GHz~1.7GHz 넓은 대역에서 동작하는 내부 슬롯과 외부 스터브를 갖는 원형편파 패치 안테나를 설계하였다. 광대역 특성과 고 이득을 갖기 위해 기본적으로 접지판으로부터 높은 공기층을 적용하였다. 임피던스 대역폭을 개선하기 위하여 패치의 크기, 매인 패치와 접지판 간거리, 내부 슬롯의 길이, 급전 위치, 외부 스터브의 길이 등을 조정하였다. 시뮬레이션을 통해 1.5GHz~1.7GHz 대역의 안테나를 설계하고 반사손실, 이득, 방사패턴 등의 안테나 특성을 확인하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.599-602
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• 2004

본 논문에서는 로봇축구의 식별을 위한 초기 패치(patch)값 및 조명의 변화량에 따른 제어변수의 자동설정 방법을 연구하였다. 먼저 패치값 자동설정을 위해 찾고자하는 국부적인 패치영역을 획득하여 RCB값으로 표본화하고, 기울기 연산자를 적용하여 화소의 기울기 값을 얻는다. 그리고 기울기 값으로부터 유효 패치영역과 YUV값을 구한다. 또한 YUV 성분 중 휘도성분을 측정하여 조명의 변화량에 따른 제어변수를 설정한다. 제안된 방법을 로봇축구 영상에 적용하여 초기 패치값을 설정하였고 경기 중 조명의 변화에 적응적인 패치값 검출이 가능함을 보였다.

• 한국산학기술학회논문지
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• 제13권8호
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• pp.3623-3627
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• 2012

인터넷이 보급된 이후로 현대사회는 본격적인 정보화시대에 진입하게 되었다. 정보화시대에 발 맞춰 인터넷은 유선인터넷에서 무선인터넷으로 발전하게 되었다. 무선인터넷의 수요가 급증하자 기존에 사용된 2.4GHz대역의 통신은 포화상태에 이르게 되었으며 효율과 성능이 현저히 떨어지게 되었다. 이에 따라 5GHz대역의 통신이 주목을 받게 되었다. 본 논문에서는 5GHz대역의 통신이 가능한 U-slot 마이크로스트립 안테나를 HFSS(High Frequency Structure Simulator)를 통해 분석 및 설계하였다. 설계된 안테나를 유전율 4.4의 FR4-epoxy기판을 이용해 제작하고 최종적으로 회로망 분석기(Network Analyzer)를 통해 안테나 특성을 평가, 분석하였다.

• Journal of Information Processing Systems
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• 제13권5호
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• pp.1183-1202
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• 2017

Image restoration has been carried out by texture synthesis mostly for large regions and inpainting algorithms for small cracks in images. In this paper, we propose a new approach that allows for the simultaneous fill-in of different structures and textures by processing in a wavelet domain. A combination of structure inpainting and patch-based texture synthesis is carried out, which is known as patch-based inpainting, for filling and updating the target region. The wavelet transform is used for its very good multiresolution capabilities. The proposed algorithm uses the wavelet domain subbands to resolve the structure and texture components in smooth approximation and high frequency structural details. The subbands are processed separately by the prioritized patch-based inpainting with isophote energy driven texture synthesis at the core. The algorithm automatically estimates the wavelet coefficients of the target regions of various subbands using optimized patches from the surrounding DWT coefficients. The suggested performance improvement drastically improves execution speed over the existing algorithm. The proposed patch optimization strategy improves the quality of the fill. The fill-in is done with higher priority to structures and isophotes arriving at target boundaries. The effectiveness of the algorithm is demonstrated with natural and textured images with varying textural complexions.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2006년도 하계학술대회
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• pp.193-196
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• 2006

In this paper, two $4{\times}4$ rectangular patch array antennas operated at 20 GHz are implemented for the satellite communication. Two $2{\times}2$ sub-arrays are designed and used for the design of $4{\times}4$ patch array. The sixteen patch antennas and microstrip feeding line are printed on the single-layered substrate. The spacing between the array elements is chosen to be $0.736{\lambda}$. The HPBW(Half Power Beam Width) of the $4{\times}4$ microstrip patch array is 17.01 degrees in the E-plane and 17.71 degrees in the H-plane with a gain of 11.6dB in the experimental results. The HPBW of the recessed $4{\times}4$ microstrip patch array is 18.66 degrees in E-plane and 17.12 degrees in the H-plane with a gain of 12.55dB in the experimental results.

• International Journal of Aeronautical and Space Sciences
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• 제6권1호
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• pp.17-26
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• 2005

An optical phase tracking technique for an extrinsic Fabry-Perot interferometer (EFPI) is proposed in order to overcome interferometric non-linearity. Basic idea is utilizing strain-rate information, which cannot be easily obtained from an EFPI sensor itself. The proposed phase tracking system consists of a patch-type EFPI sensor and a simple on-line phase tracking logic. The patch-type EFPI sensor comprises an EFPI and a piezoelectric patch. An EFPI sensor itself has non-linear behavior due to the interferometric characteristics, and a piezoelectric material has hysteresis. However, the composed patch-type EFPI sensor system overcomes the problems that can arise when they are used individually. The dynamic characteristics of the proposed phase tracking system were investigated, and then the patch-type EFPI sensor system was applied to the active suppression of flutter, dynamic aeroelastic instability, of a swept-back composite plate structure. The proposed system has effectively reduced the amplitude of the flutter mode, and increased flutter speed.

• Journal of information and communication convergence engineering
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• 제10권2호
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• pp.123-128
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• 2012

In communication systems, there are various types of microstrip antenna that can be used for many applications. This paper mainly focuses on the simple design of an inset rectangular microstrip patch antenna to operate at a frequency of 2.45 GHz for rectenna design. The study involves using an high frequency structure simulator to design the antenna dimensions and to determine its performance. This antenna is based on a thickness of 1.6 mm flame retardant 4 (FR-4) substrate having a dielectric constant of approximately 4.7, an inset feed, and a ground plane. After simulation, the antenna performance characteristics such as its return loss, voltage standing wave ratio, gain, and radiation pattern were obtained and compared with the fabricated measured antenna.