• 한국지능시스템학회논문지
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• 제24권4호
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• pp.437-442
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• 2014

최근에는 크기 및 비용의 관점에서 많은 장점을 갖는 초소형 해양로봇(Micro Marine Robot : MMR)의 개발 및 적용에 대한 요구가 증가하고 있다. 하지만 국내에서는 그 기반이 매우 부족한 상황이다. 다행히도 초소형 수상로봇(Micro Surface Robot : MSR)의 장애물회피와 관련해서는 크기와 성능의 관점에서 최적화되어 4방향 탐지가 가능한 장애물회피소나(Obstacle Avoidance Sonar : OAS)가 개발되었으나, 제한된 빔폭(beam width) 및 탐지거리를 갖는 고정 소나빔의 사용으로 인하여 장애물의 형상에 따라 탐지성능이 저하되는 문제점이 존재했다. 이러한 문제를 해결하기 위하여, 본 논문에서는 평기어(spur gear) 및 서보모터를 활용하여 회전 소나빔을 구현한 MSR의 메커니즘을 제안하였다. 제안된 메커니즘의 검증을 위해 다각 평면 장애물에 대한 MSR의 벽면 추적(wall-tracking) 문제를 고려하였고, 탐지성능 및 구동명령 측면에서 기존의 고정 소나빔 적용 시와 비교 및 분석을 수행하였다. 실험결과는 제안된 메커니즘의 타당성을 보여준다.

• 한국인터넷방송통신학회논문지
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• 제15권1호
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• pp.61-68
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• 2015

최근 스마트폰의 급속한 확대로 다양한 형태의 보안 위협이 증가하고 있다. 그 중 감염된 스마트폰은 개인정보 유출뿐만 아니라 사이버 테러와 같은 DDOS 공격에도 악용될 수 있어 매우 위험하다. 하지만 기존 기법들은 배터리를 사용하는 스마트폰에서는 적합하지 않거나 별도의 저장소를 필요로 하는 문제점이 있다. 본 논문에서는 스마트폰에서 효율적인 봇 탐지 기법을 제안한다. 제안 기법은 수신 트래픽을 대상으로 탐지하는 기존 기법과 다르게 제안 기법은 송신 트래픽만을 대상으로 탐지하므로 수신 트래픽보다 송신 트래픽이 적은 스마트폰에서 더욱 에너지 효율적이다. 또한 의도하지 않은 트래픽을 유발하는 로그 정보들을 외부 통합 서버에 수집하여 봇뿐만 아니라 봇넷을 탐지할 수 있다. 제안 기법을 안드로이드 스마트폰에서 구현하고 성능 평가를 한 결과 효과적으로 봇을 탐지할 수 있음을 확인하였다.

• Journal of Communications and Networks
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• 제7권3호
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• pp.337-352
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• 2005

In this paper, a fuzzy logic implementation of the random early detection (RED) mechanism [1] is presented. The main objective of the proposed fuzzy controller is to reduce the loss probability of the RED mechanism without any change in channel utilization. Based on previous studies, it is clear that the performance of RED algorithm is extremely related to the traffic load as well as to its parameters setting. Using fuzzy logic capabilities, we try to dynamically tune the loss probability of the RED gateway. To achieve this goal, a two-input-single-output fuzzy controller is used. To achieve a low packet loss probability, the proposed fuzzy controller is responsible to control the $max_{p}$ parameter of the RED gateway. The inputs of the proposed fuzzy controller are 1) the difference between average queue size and a target point, and 2) the difference between the estimated value of incoming data rate and the target link capacity. To evaluate the performance of the proposed fuzzy mechanism, several trials with file transfer protocol (FTP) and burst traffic were performed. In this study, the ns-2 simulator [2] has been used to generate the experimental data. All simulation results indicate that the proposed fuzzy mechanism out performs remarkably both the traditional RED and Adaptive RED (ARED) mechanisms [3]-[5].

• 한국정보통신학회논문지
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• 제16권1호
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• pp.98-106
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• 2012

컨테이너 보안 장치(CSD)는 컨테이너의 문 안에 장착되어 센서를 통해 컨테이너의 문이 비정상적으로 열리는 것을 탐지하는 장치다. 이러한 CSD 장치는 컨테이너의 보안성을 제공하는 장치이기 때문에 도청이나 위조와 같은 공격에 안전해야할 뿐만 아니라 복제 되어서도 안된다. 만약 복제된 CSD를 탐지할 수 없다면, CSD는 공격자에 의해 불법적으로 복제되어 정상적인 목적과는 다른 용도로 사용되어 질 수 있다. 본 논문에서는 이러한 복제된 CSD를 탐지하기 위한 정책 기반 복제 탐지 메커니즘을 제안한다. 또한 실제 구현 결과를 통해 제안하는 기법을 검증 및 평가한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권11호
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• pp.5580-5593
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• 2019

A malicious Uniform Resource Locator (URL) recognition and detection method based on the combination of Attention mechanism with Convolutional Neural Network and Long Short-Term Memory Network (Attention-Based CNN-LSTM), is proposed. Firstly, the WHOIS check method is used to extract and filter features, including the URL texture information, the URL string statistical information of attributes and the WHOIS information, and the features are subsequently encoded and pre-processed followed by inputting them to the constructed Convolutional Neural Network (CNN) convolution layer to extract local features. Secondly, in accordance with the weights from the Attention mechanism, the generated local features are input into the Long-Short Term Memory (LSTM) model, and subsequently pooled to calculate the global features of the URLs. Finally, the URLs are detected and classified by the SoftMax function using global features. The results demonstrate that compared with the existing methods, the Attention-based CNN-LSTM mechanism has higher accuracy for malicious URL detection.

• 한국정밀공학회지
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• 제25권2호
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• pp.65-71
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• 2008

In this paper, we propose a new driving mode control algorithm for a mobile robot based on obstacle detection. The robot has a variable geometry single-tracked mechanism, so it can maximize a contact length with ground for the adaptability to off-road and puesue a stable system due to the lower center of gravity. However this robot system embodied passive type according to operator. In this reason, several problems are detected. So, this research presents a new method of obstacle detection using PSD infrared sensors and translates the variable tracks on the best suited driving mode actively. And experimental results about mentioned are presented.

• 한국멀티미디어학회논문지
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• 제18권3호
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• pp.359-367
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• 2015

In this paper, we propose intelligent fire learning and detection system using hybrid visual attention mechanism of human. Proposed fire learning system generates leaned data by learning process of fire and smoke images. The features used as learning feature are selected among many features which are extracted based on bottom-up visual attention mechanism of human, and these features are modified as learned data by calculating average and standard variation of them. Proposed fire detection system uses learned data which is generated in fire learning system and features of input image to detect fire.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 춘계학술발표대회 논문집
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• pp.27-30
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• 2003

In order to apply fracture detection we fabricated the CP-FRP using carbon-powder and analyzed conductive mechanism of it. The composites showed lower initial resistance as the carbon powder and amount of glass fiber(TEX) was used much more. When those are compared with each other that before and after bending test, the more cracks observed in matrix after bending test. We become to know that the conductivity of the composites depends on percolation structure of carbon powder.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3738-3750
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• 2015

Sybil attack is a special kind of attack which is difficult to be detected in Wireless Sensor Network (WSN). So a lightweight detection mechanism based on LEACH-RSSI-ID (LRD) is proposed in this paper. Due to the characteristic of Low-Energy Adaptive Clustering Hierarchy (LEACH) protocol, none of nodes can be the cluster head forever.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권3호
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• pp.224-235
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• 2017

Purpose: Reliability is the most important factor to detect defects as wind turbines are deployed in large blades. The methods of detecting defects are various, such as non-destructive inspection and thermal imaging inspection. We propose the phased array ultrasonic testing method of non-destructive testing. Methods: We propose the active pressure mechanism for wind power blade. The phase array ultrasonic inspection method is used for fault detection inner blade surface. Controlled pressure of mechanism with respect to z-axis is important for guarantee the result of phase array ultrasonic inspection. The model based control and proposed mechanism are utilized for overall system stability and effectiveness of system. Result: The result of proposed pressure mechanism B is more stable than A. Convergence speed is also faster than A. Conclusion: We confirmed the performance of the proposed constant pressure mechanism through experiments. Non-destructive testing was applied to the specimen to confirm the reliability of detecting defects.