• 전기전자학회논문지
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• 제8권2호
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• pp.161-165
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• 2004

본 논문은 CMOS 에지 완료검출 신호를 이용하여 8bit 웨이브파이프라인 덧셈기를 설게하였다. 이 구조는 클럭이 필요 없이 동작한다. 에지감지후 신호완료를 검출하는 알고리즘회로는 센서회로와 래치로 구성되어있다. 제안하는 구조를 이용하여 8bit 덧셈기의 출력이 거의 같은 시간에 만들어 지도록 정렬된다. 시뮬레이션에서 0.35um CMOS 공정을 사용하여 3.3V 공급전압으로 1GHz 동작을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권3호
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• pp.1287-1300
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• 2018

Target-tracking algorithm based on ad hoc camera sensor networks (ACSNs) utilizes the distributed observation capability of nodes to achieve accurate target tracking. A compressed sensing-based multiple-target tracking algorithm (CSMTTA) for ACSNs is proposed in this work based on the study of camera node observation projection model and compressed sensing model. The proposed algorithm includes reconfiguration of observed signals and evaluation of target locations. It reconfigures observed signals by solving the convex optimization of L1-norm least and forecasts node group to evaluate a target location by the motion features of the target. Simulation results show that CSMTTA can recover the subtracted observation information accurately under the condition of sparse sampling to a high target-tracking accuracy and accomplish the distributed tracking task of multiple mobile targets.

• 대한원격탐사학회지
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• 제26권6호
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• pp.681-691
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• 2010

LiDAR waveform decomposition plays an important role in LiDAR data processing since the resulting decomposed components are assumed to represent reflection surfaces within waveform footprints and the decomposition results ultimately affect the interpretation of LiDAR waveform data. Decomposing the waveform into a mixture of Gaussians involves two related problems; 1) determining the number of Gaussian components in the waveform, and 2) estimating the parameters of each Gaussian component of the mixture. Previous studies estimated the number of components in the mixture before the parameter optimization step, and it tended to suggest a larger number of components than is required due to the inherent noise embedded in the waveform data. In order to tackle these issues, a new LiDAR waveform decomposition algorithm based on the sequential approach has been proposed in this study and applied to the ICESat waveform data. Experimental results indicated that the proposed algorithm utilized a smaller number of components to decompose waveforms, while resulting IMP value is higher than the GLA14 products.

• 한국컴퓨터정보학회논문지
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• 제21권1호
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• pp.73-78
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• 2016

In wireless sensor networks, sensors have capabilities of sensing and wireless communication, computing power and collect data such as sound, movement, vibration. Sensors need to communicate wirelessly to send their sensing data to other sensors or the base station and so they are vulnerable to many attacks like garbage packet injection that cannot be prevented by using traditional cryptographic mechanisms. To defend against such attacks, a behavior-based attack detection is used in which some specialized monitoring nodes overhear the communications of their neighbors(normal nodes) to detect illegitimate behaviors. It is desirable that the total sensing area of normal nodes covered by monitoring nodes is as large as possible. The previous researches have focused on selecting the monitoring nodes so as to maximize the number of normal nodes(node coverage), which does not guarantee that the area sensed by the selected normal nodes is maximized. In this study, we have developed an algorithm for selecting the monitoring nodes needed to cover the maximum sensing area. We also have compared experimentally the covered sensing areas computed by our algorithm and the node coverage algorithm.

• 한국컴퓨터정보학회논문지
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• 제10권5호
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• pp.141-150
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• 2005

무선 센서 네트워크는 센서 테크놀로지의 발전으로 인하여 급속히 개발되고 있으며, 여러 분야에서 다양하게 응용될 것으로 예측된다. 무선 센서 네트워크에서 가장 중요한 요소는 네트워크를 에너지 효율적으로 운용하는 것이다. 이러한 목적을 충족시키기 위해 여러 라우팅 프로토콜이 제시되었다. 그러나 기존의 연구들은 모든 센서 노드들이 센싱 데이터를 갖고 있다는 이상적인 상황을 가정하고 있다. 본 논문에서는 일부 센서 노드들만이 데이터를 갖고 있는 센서 네트워크 상에서 클러스터 헤드를 선정하는 센싱 인지 클러스터 선정 알고리즘을 LEACH-C 기반으로 설계 및 구현하였다. 또한 제안된 알고리즘을 여러 네트워크 상황에서 시뮬레이션하여 센싱 인지 기법이 가장 효율적인 네트워크 상황을 분석하였다. 시뮬레이션 결과에서 데이터를 센싱한 노드군(群)을 중심으로 클러스터 헤드를 선정하는 것이 가장 효율적임을 알 수 있었으며, 일부 센서들만이 데이터를 갖고 있는 경우에는 센싱 인지 개념을 클러스터 헤드 선정에 적용하는 것이 중요하다는 점을 보여주었다.

• Journal of Communications and Networks
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• 제17권5호
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• pp.517-524
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• 2015

The fast and accurate spectrum sensing over an ultra-wide bandwidth is a big challenge for the radio environment cognition. Considering sparse signal feature, two novel compressed sensing schemes are proposed, which can reduce compressed sampling rate in contrast to the traditional scheme. One algorithm is dynamically adjusting compression ratio based on modulation recognition and identification of symbol rate, which can reduce compression ratio. Furthermore, without priori information of the modulation and symbol rate, another improved algorithm is proposed with the application potential in practice, which does not need to reconstruct the signals. The improved algorithm is divided into two stages, which are the approaching stage and the monitoring stage. The overall sampling rate can be dramatically reduced without the performance deterioration of the spectrum detection compared to the conventional static compressed sampling rate algorithm. Numerous results show that the proposed compressed sensing technique can reduce sampling rate by 35%, with an acceptable detection probability over 0.9.

• 센서학회지
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• 제22권4호
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• pp.268-275
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• 2013

Efficient energy management becomes a critical design issue for complex WSN (Wireless Sensor Network). Most of complex WSN employ the sleep mode to reduce the energy dissipation. However, it should cause the reduction of sensing coverage. This paper presents new wake-up algorithm for reducing energy consumption in complex WSN. The proposed wake-up algorithm is devised using geometric probability. It determined which node will be waked-up among the nodes having overlapped sensing coverage. The only one sensor node will be waked-up and it is ready to sense the event occurred uniformly. The simulation results show that the lifetime is increased by 15% and the sensing coverage is increased by 20% compared to the other scheduling methods. Consequently, the proposed wake-up algorithm can eliminate the power dissipation in the overlapped sensing coverage. Thus, it can be applicable for the various WSN suffering from the limited power supply.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1272-1274
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• 2003

In this paper, we present a new algorithm for high dimensional data reduction based on wavelet decomposition and Genetic Algorithm (GA). Comparative results show the superiority of our algorithm for dimensionality reduction and accuracy improvement.

• 대한원격탐사학회지
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• 제18권5호
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• pp.291-297
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• 2002

Optimal allocation of viewers on a terrain in such a wav that the hidden area would be minimized has many practical applications. However, it is impossible in practical sense to evaluate all the possible allocations. In this paper, we propose an optimal allocation of viewers based on genetic algorithm that enables probabilistic search of huge solution space. An experiment for one and three viewers was performed. The algorithm converges to good solutions. Especially, in one viewer case, the algorithm found the best solution.

• 한국항행학회논문지
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• 제13권3호
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• pp.378-384
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• 2009

본 논문에서는 주파수 사용 효율 증대를 위한 사이클로스테이션너리 특징 검출 (Cyclostationary Feature Detection; CFD)방식의 ATSC 신호 검출 알고리듬을 고려한다. 현재 IEEE 802.22 표준화 기구에 제안된 알고리듬들 중 IEEE 802.22의 권고사항을 충분히 만족시키는 알고리듬으로 사이클로스테이션너리 특징 검출 방식에 기반한 톰슨(Thomson)사의 알고리듬이 있다. 본 논문에서는 톰슨사의 알고리듬보다 계산량이 적으면서 톰슨사의 알고리즘의 성능에 필적할 만한 성능을 갖는 보간법 기반 ATSC 스펙트럼 센싱 알고리듬을 제안한다. 제안하는 보간법 기반 알고리듬은 시간영역에서의 영삽입(Zero-Padding) 방법과 효과적인 센싱 스캔 방법을 사용하여 적은 계산량으로 톰슨사의 성능에 필적하는 성능을 보여준다.