• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.197-200
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• 2000

본 논문에서는 교통정보 수집용 영상검지기를 위한 실제 교차로 상황에 잘 맞는 배경영상 생성 방법을 제안한다. 교차로 특성상 진행중인 차량 및 신호 대기중인 차량 등 여러 가지 통행패턴이 있을 수 있는데 차량의 움직임 정보를 추출하기 위해 장면차이 방법을 사용한다. 영상열내 차량의 움직임을 관찰하여 배경영상의 생성 과정에 선택적으로 부분 영역을 반영함으로써 보다 좋은 초기 배경영상을 얻을 수 있다. 기존 방법으로 해결하지 못하는 복잡한 상황하에서의 좋은 초기 배경영상을 생성하므로, 차량으로 탐지되지 않는 영상의 부분영역만을 배경생성 과정에 참여시키는 기존의 배경생성 방법에 이 방법을 사용할 경우, 복잡한 상황에서도 견고하게 차량 탐지를 할 수 있는 배경영상을 생성할 수 있다.

• Annual Conference on Human and Language Technology
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• 2020.10a
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• pp.103-107
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• 2020

의존구조 말뭉치는 자연언어처리 분야에서 문장의 의존관계를 파악하는데 널리 사용된다. 이러한 말뭉치는 일반적으로 오류가 없다고 가정하지만, 현실적으로는 다양한 오류를 포함하고 있다. 이러한 오류들은 성능 저하의 요인이 된다. 이러한 문제를 완화하려고 본 논문에서는 XGBoost와 교차검증을 이용하여 이미 구축된 구문분석 말뭉치로부터 오류를 탐지하는 방법을 제안한다. 그러나 오류가 부착된 학습말뭉치가 존재하지 않으므로, 일반적인 분류기로서 오류를 검출할 수 없다. 본 논문에서는 분류기의 결과를 분석하여 오류를 검출하는 방법을 제안한다. 성능을 분석하려고 표본집단과 모집단의 오류 분포의 차이를 분석하였고 표본집단과 모집단의 오류 분포의 차이가 거의 없는 것으로 보아 제안된 방법이 타당함을 알 수 있었다. 앞으로 의미역 부착 말뭉치에 적용할 계획이다.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.2
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• pp.63-69
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• 2013

Change detection technique is essential to various applications of Very High-Resolution(VHR) satellite imagery and land monitoring. However, change detection accuracy of VHR satellite imagery can be decreased due to various geometrical dissimilarity. In this paper, the existing fusion evaluation indexes were revised and applied to improve VHR imagery based change detection accuracy between multi-temporal images. In addition, appropriate change detection methodology of VHR images are proposed through comparison of general change detection algorithm with cross-sharpened image based change detection algorithm. For these purpose, ERGAS, UIQI and SAM, which were representative fusion evaluation index, were applied to unsupervised change detection, and then, these were compared with CVA based change detection result. Methodologies for minimizing the geometrical error of change detection algorithm are analyzed through evaluation of change detection accuracy corresponding to image fusion method, also. The experimental results are shown that change detection accuracy based on ERGAS index by using cross-sharpened images is higher than these based on other estimation index by using general fused image.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.1
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• pp.60-69
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• 2014

Footstep detection using seismic sensors for security is a very meaningful task, but readings can easily fluctuate due to noise in outdoor environment. We propose NSSC method based on nonlinear spectral subtraction and cross-correlation using prime footstep model signal as a footstep signal refining process that enhances the signal-to-noise ratio (SNR) and attenuates noise. After de-noising, a detection event classification method is presented as further refining process to ensure that the detection result is a footstep. To validate the proposed algorithm, representative experiments including sunny and rainy-day cases are demonstrated.

• Journal of Internet Computing and Services
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• v.9 no.6
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• pp.27-35
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• 2008

With the proliferation of wireless devices, mobile ad-hoc networking (MANETS) has become a very exciting and important technology. However, MANET is more vulnerable than wired networking. Existing security mechanisms designed for wired networks have to be redesigned in this new environment. In this paper, we discuss the problem of anomaly detection in MANET. The focus of our research is on techniques for automatically constructing anomaly detection models that are capable of detecting new or unseen attacks. We propose a new anomaly detection method for MANETs. The proposed method performs cross-feature analysis on the basis of Rough sets to capture the inter-feature correlation patterns in normal traffic. The performance of the proposed method is evaluated through a simulation. The results show that the performance of the proposed method is superior to the performance of Huang method that uses cross-feature based on the probability of feature attribute value. Accordingly, we know that the proposed method effectively detects anomalies.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.4
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• pp.297-304
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• 2015

The change detection algorithms, based on remotely sensed satellite imagery, can be applied to various applications, such as the hazard/disaster analysis and the land monitoring. However, unchanged areas sometimes detected as the changed areas due to various errors in relief displacements and noise pixels, included in the original multi-temporal dataset at the application of unsupervised change detection algorithm. In this research, the object-based changed detection for the high-spatial resolution satellite images is applied by using the IR-MAD (Iteratively Reweighted- Multivariate Alteration Detection), which is one of those representative change detection algorithms. In additionally, we tried to increase the accuracy of change detection results with using the additional information, based on the cross-sharpening method. In the experiment, we used the KOMPSAT-2 satellite sensor, and resulted in the object-based IR-MAD algorithm, representing higher changed detection accuracy than that by the pixel-based IR-MAD. Also, the object-based IR-MAD, focused on cross-sharpened images, increased in accuracy of changed detection, compared to the original object-based IR-MAD. Through these experiments, we could conclude that the land monitoring and the change detection with the high-spatial-resolution satellite imagery can be accomplished efficiency by using the object-based IR-MAD algorithm.

• The Korean Journal of Applied Statistics
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• v.22 no.5
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• pp.923-935
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• 2009

This study aims to explore a recommended model of decision tree to predict a hard-to-measure measurement in anthropometric survey. We carry out an experiment on cross validation study to obtain a recommened model of decision tree. We use three split rules of decision tree, those are CHAID, Exhaustive CHAID, and CART. CART result is the best one in real world data.

• Korean Journal of Remote Sensing
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• v.34 no.5
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• pp.777-786
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• 2018

GF (Guided Filtering) is a representative image processing technique to effectively remove noise while preserving edge information in the digital image. In this paper, we proposed a unsupervised change detection method for the KOMPSAT-3 satellite image using the GF and evaluated its performance. In order to utilize GF for the unsupervised change detection, cross-sharpened images were generated based on GF, and CVA (Change Vector Analysis) was applied to the generated cross-sharpened images to extract the changed area in the multitemporal satellite imagery. Experimental results using KOMPSAT-3 satellite images showed that the proposed method can be effectively used to detect changed regions compared with CVA results based on existing cross-sharpened images.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.431-434
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• 2020

본 논문에서는 악성코드탐지 기법으로 n-grams를 사용한 특징 추출을 통해 이미지 인식 분야에서 널리 쓰이는 Convolutional Neural Network로 학습하는 프레임워크를 제안한다. 윈도우즈 실행 파일의 PE 포맷에서 특징을 추출하여 6-grams 확률을 구하고 grayscale 을 통해 이미지로 변환한다. 이것을 기존에 연구된 탐지방법과 비교하여 우수함을 보인다. 학습에 사용된 데이터는 총 55,000개로 5-folds 교차검증을 하였으며 예측 정확도는 98.87%였다.

• The Journal of the Acoustical Society of Korea
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• v.36 no.1
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• pp.30-38
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• 2017

In this paper, we propose an underwater acoustic sensor fault detection method for passive sonar systems. In general, a passive sonar system displays processed results of array signals obtained from tens of the acoustic sensors as a two-dimensional image such as displays for broadband or narrowband analysis. Since detection result display in the operation software is to display the accumulated result through the array signal processing, it is difficult to determine the possibility where signal may be contaminated by the fault or failure of a single channel sensor. In this paper, accordingly, we propose a detection method based on the analysis of RMSCR (Root Mean Square Crossing-Rate), and the processing techniques for the faulty sensors are analyzed. In order to evaluate the performance of the proposed method, the precision of detecting fault sensors is measured by using signals acquired from real array being operated in several coastal areas. Besides, we compare performance of fault processing techniques. From the experiments, it is shown that the proposed method works well in underwater environments with high average RMS, and mute (set to zero) shows the best performance with regard to fault processing techniques.