• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.407-407
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• 2017

홍수 예측을 위한 분포형 수문모형의 유출해석에서 하도추적은 수리학적 하도 추적과 수문학적 하도 추적 방법이 있다. 수리학적 하도 추적은 운동파 방정식, 확산파 방정식 등을 이용하여 수리현상을 시간과 공간으로 편미분하여 홍수량 예측을 한다. 수리적 하도 추적은 시간적, 공간적 안정조건(stability condition)을 만족해야된다. 면적이 큰 유역에서 적용할 때에는 계산에 소요되는 시간이 크다. 그러므로 국지호우로 인한 돌방홍수 예 경보를 위해서는 준실시간 또는 실시간 홍수 감시 및 예측이 필요하므로 계산에 소요되는 시간이 큰 수리학적 하도추적을 이용한 홍수 예측은 한계를 가진다. 본 연구에서는 유역면적이 큰 유역의 준실시간 홍수 감시 및 예측을 위하여 수문학적 하도추적 기법은 하천차수별 저류상수를 적용한 multi-Muskingum방법을 개발하여 모의하였다. multi-Muskingum 적용한 결과 모의시간이 상당히 단축되었으며 자료동화 기법을 통하여 모형의 정확도를 개선하였다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.31-41
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• 2010

It is difficult to identify attacker's real location when the attacker spoofs IP address in current IPv4-based Internet environment. If the attacks such as DDoS happen in the Internet, we can hardly expect the protection scheme to respond to these attacks in active or real-time manner. Many traceback techniques have been proposed to protect against these attacks, but most traceback schemes were designed to work with the IPv4-based Internet and found to be lack of verification of whether the traceback related information is forged or not. Few traceback schemes for IPv6-based network environment have been suggested, but it has these disadvantages that needs more study. In this paper, we propose the reliable IP traceback scheme supporting integrity of traceback-related information in IPv6 network environment, simulate it, and compare our proposed scheme with exsisting traceback mechanisms in terms of overhead and functionality.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.177-180
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• 2015

본 논문에서는 비디오 영상을 입력 했을 때 특징점 추적을 통한 다수 영상의 고속 스트칭 기법을 제안한다. 빠른 속도로 특징점 추출을 위해서 FAST(Features from Accelerated Segment Test) 기법을 사용한다. 특징점 정합과정은 기존의 방법과는 다른 새로운 방법을 제안한다. Mean shift 를 통해 특징점이 포함된 영역을 추적하여 벡터(vector)를 구한다. 이 벡터를 사용하여 추출한 특징점들을 정합하는데 사용한다. 마지막으로 이상점(outlier)을 제거하기 위해 RANSAC(RANdom Sample Consensus) 기법을 사용한다. 입력된 두 영상의 호모그래피(homography) 변환 행렬을 구하여 하나의 파노라마 영상을 생성한다. 실험을 통해 제안하는 기법이 기존의 기법보다 속도가 향상되는 것을 확인하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.12
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• pp.1105-1111
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• 2016

In modern warfare, various target tracking radars are used for target location tracking. So, the importance of EA radar jamming technique which disrupt enemy target tracking radar in oder to neutralize tararget location tracking has increased. VGPO/I jamming is a base technique of EA(Electronic Attack), it is possible to operate to pulse-Doppler radar. In this papar, we develop VGPO/I jamming technique that can apply to phase sampled DRFM by using phase information and verifiy through simulations.

• Journal of IKEEE
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• v.13 no.2
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• pp.232-240
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• 2009

This paper presents a robust vehicle detection and tracking algorithm for supervision of illegal parking. The proposed algorithm is composed of four parts. First, a vehicle detection algorithm is proposed using the improved codebook object detection algorithm to segment moving vehicles from the input sequence. Second, a preprocessing technique using the geometric characteristics of vehicles is employed to exclude non-vehicle objects. Then, the detected vehicles are tracked by an object tracker which incorporates histogram tracking method with Kalman filter. To make the tracking results more accurate, histogram tracking results are used as measurement data for Kalman filter. Finally, Real Stop Counter (RSC) is introduced for trustworthy and accurate performance of the stopped vehicle detection. Experimental results show that the proposed algorithm can track multiple vehicles simultaneously and detect stopped vehicles successfully in the complicated street environment.

• Journal of Korea Multimedia Society
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• v.7 no.8
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• pp.1120-1130
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• 2004

Distributed Denial-of-Service(DDoS) attack prevent users from accessing services on the target network by spoofing its origin source address with a large volume of traffic. The objective of IP Traceback is to determine the real attack sources, as well as the full path taken by the attack packets. Existing IP Traceback methods can be categorized as proactive or reactive tracing. Existing proactive tracing scheme(such as packet marking and messaging) prepares information for tracing when packets are in transit. But, these scheme require additional network overhead. In this paper, we propose a "advanced Traceback" mechanism, which is based on the modified Pushback system with secure router mechanism. Proposed mechanism can detect and control DDoS traffic on router and can generate marked packet for reconstructing origin DDoS attack source, by which we can diminish network overload and enhance Traceback performance.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.1
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• pp.1-8
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• 2013

This study focuses on a ship detection and tracking method using Frequency Modulated Continuous Wave (FMCW) radar used for horizontal surveillance. In general, FMCW radar can play an important role in maritime surveillance, because it has many advantages such as low warm-up time, low power consumption, and its all weather performance. In this paper, we introduce an effective method for data and signal processing of ship's detecting and tracking using the X-band radar. Ships information was extracted using an image-based processing method such as the land masking and morphological filtering with a threshold for a cycle data merged from raw data (spoke data). After that, ships was tracked using search-window that is ship's expected rectangle area in the next frame considering expected maximum speed (19 kts) and interval time (5 sec). By using this method, the tracking results for most of the moving object tracking was successful and those results were compared with AIS (Automatic Identification System) for ships position. Therefore, it can be said that the practical application of this detection and tracking method using FMCW radar improve the maritime safety as well as expand the surveillance coverage cost-effectively. Algorithm improvements are required for an enhancement of small ship detection and tracking technique in the future.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.159-166
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• 2013

Recently, because the interest and needs in privacy protection are growing, smartcard-based remote user authentication schemes have been actively studied to provide the user anonymity. In 2008, Kim et al. first proposed an authentication scheme in order to ensure the user anonymity against both external attackers and the remote server and track malicious users with the help of a trusted trace sever. However, in 2010, Lee et al. showed that Kim et al.'s scheme cannot provide the user anonymity against remote server, which is because the server can trace users without any help of the trace server, and then proposed a improved scheme. On the other hand, in 2010, Horng et al. proposed an authentication scheme with non-tamper resistant smart cards, in which the non-tamper resistant smart card means that an attacker may find out secret information stored in the smart card through special data analysis techniques such as monitoring power consumption, to be secure against a variety of attacks and to provide the user anonymity against external attackers. In this paper, we will propose a remote user authentication scheme with non-tamper resistant smart cards not only to ensure the user anonymity against both external attackers and the remote server but also to track malicious users with only the help of a trusted trace sever.

• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.77-85
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• 2005

MPPT(Maximum power point tracking) is used in photovoltaic systems to maximize the solar array output power, irrespective of the temperature and irradiation conditions and of the load electrical characteristics. In this paper, new MPPT algorithm is proposed for the small satellite in LEO. As the proposed MPPT algorithm does not need any calculation of power by multiplication of voltage and current, it can be made by the simply analog circuit. In this study, the proposed MPPT algorithm is verified by the simulation and experimental in the many conditions that can change the characteristics of the solar array.

• Journal of Internet Computing and Services
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• v.6 no.1
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• pp.13-25
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• 2005

Distributed Denial-of-Service(DDoS) attack prevent users from accessing services on the target network by spoofing its origin source address with a large volume of traffic. The objective of IP Traceback is to determine the real attack sources, as well as the full path taken by the attack packets. Existing IP Traceback methods can be categorized as proactive or reactive tracing. Existing PPM based tracing scheme(such as router node appending, sampling and edge sampling) insert traceback information in IP packet header for IP Traceback. But, these schemes did not provide enhanced performance in DDoS attack. In this paper, we propose a 'TTL based advanced Packet Marking' mechanism for IP Traceback. Proposed mechanism can detect and control DDoS traffic on router and can generate marked packet for reconstructing origin DDoS attack source, by which we can diminish network overload and enhance traceback performance.