• Journal of Korea Spatial Information System Society
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• v.10 no.3
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• pp.55-65
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• 2008

For obtaining telematics traffic information(travel time or speed in an individual link), there are many kinds of devices to collect traffic data. Since the GPS satellite signals have been released to civil society, thank to the development of GPS technology, the GPS has become a very useful instrument for collecting traffic data. GPS can reduce the cost of installation and maintenance in contrast with existing traffic detectors which must be stationed on the ground. But. there are Problems when GPS data is applied to the existing filtering techniques used for analyzing the data collected by other detectors. This paper proposes a method to provide users with correct traffic information through filtering abnormal data caused by the unusual driving in collected data based on GPS. We have developed an algorithm that can be applied to real-time GPS data and create more reliable traffic information, by building patterns of past data and filtering abnormal data through selection of filtering areas using Quartile values. in order to verify the proposed algorithm, we experimented with actual traffic data that include probe cars equipped with a built-in GPS receiver which ran through Gangnam Street in Seoul. As a result of these experiments, it is shown that link travel speed data obtained from this algorithm is more accurate than those obtained by existing systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10C
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• pp.1023-1032
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• 2003

Object-based coding, such as MPEG-4, enables various content-based functionalities for multimedia applications. In order to support such functionalities, as well as to improve coding efficiency, each frame of video sequences should be segmented into video objects. In this paper. we propose an effective video object segmentation method using nonlinear multiscale filtering and spatio-temporal information. Proposed method performs a spatial segmentation using a nonlinear multiscale filtering based on the stabilized inverse diffusion equation(SIDE). And, the segmented regions are merged using region adjacency graph(RAG). In this paper, we use a statistical significance test and a time-variant memory as temporal segmentation methods. By combining of extracted spatial and temporal segmentations, we can segment the video objects effectively. Proposed method is more robust to noise than the existing watershed algorithm. Experimental result shows that the proposed method improves a boundary accuracy ratio by 43% on "Akiyo" and by 29% on "Claire" than A. Neri's Method does.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.6
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• pp.1171-1179
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• 2021

Image forensic is performed to check image limpidness. In this paper, a robust scheme is discussed to detect median filtering in low quality images. Detection of median filtering assists in overall image forensic. Improved spatial statistical features are extracted from the image to classify pristine and median filtered images. Image array data is rescaled to enhance the spatial statistical information. Features are extracted using Markov model on enhanced spatial statistics. Multiple difference arrays are considered in different directions for robust feature set. Further, texture operator features are combined to increase the detection accuracy and SVM binary classifier is applied to train the classification model. Experimental results are promising for images of low quality JPEG compression.

• Journal of KIISE:Databases
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• v.35 no.5
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• pp.421-431
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• 2008

Recently XML is becoming a de facto standard for online data exchange between heterogeneous systems and also the research of streaming XML data filtering comes into the spotlight. Since streaming XML data filtering technique needs rapid matching of queries with XML data, it is required that the query processing should be efficiently performed. Until now, most of researches focused only on partial sharing of path expressions or efficient predicate processing and they were work for time and space efficiency. However, if containment relationship between queries is previously calculated and the lowest level query is matched with XML data, we can easily get a result that high level queries can match with the XML data without any other processing. That is, using this containment technique can be another optimal solution for streaming XML data filtering. In this paper, we suggest an efficient XML data filtering based on prime number indexing and containment relationship between queries. Through some experimental results, we present that our suggested method has a better performance than the existing method. All experiments have shown that our method has a more than two times better performance even though each experiment has its own distinct test purpose.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.10a
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• pp.429-434
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• 1997

영상 평활화(Image Smoothing) 작업은 영상 신호 표본화, 정량화, 통신 이동과 같은 과정을 거치면서 잡음 등의 불필요한 신호가 포함된 디지털 영상의 잡음을 감소키는데 많이 이용되고 있다. 이와 같은 영상 평활화 작업에는 대부분 전역적인 공간 영역 혹은 주파수 영역의 전역적인 필터링 기법이 이용되고 있다. 그러나, 기존의 방법들은 왜곡된 잡음 픽셀들의 정보를 그대로 반영하기 때문에 잡음 제거 결과 복원 영상의 선명도는 크게 저해된다. 본 논문에서는 특히나 양자화 과정을 통해 잡음 정보의 변형이 극대화되어지는 압축 영상을 대상으로 하여 적절한 잡음제거 기법을 제안하고자 한다. 특히, 압축 영상의 잡음 추출은 1차 복호화 후의 공간 도메인에서, 추출된 잡음 제거는 주파수 도메인에서 수행함으로써 2차 복호화 후의 잡음제거 결과 영상은 압축 영상의 잡음 제거에 따른 본질적인 문제를 해결하였으며, 실험 결과 역시 다른 기존의 방법에 비해 우수한 성능을 발휘하였다.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.505-514
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• 2005

Image upsampling can be performed in both spatial and frequency (transform) domain. In the spatial domain, various upsampling techniques are developed and 6-tap FIR interpolation filter is most well known method, which is embedded in many video coding standards. It can provide high subjective quality but shows low objective quality. In the transform domain, simple zero padding method can produce upsampled image easily. It shows better objective quality than 6-tap filtering, but it yields ringing effects which annoy eyes. In this paper, we present efficient upsampling method using frequency addition method in transform domain to provide better subjective and objective quality than conventional method Extensive simulation results show that the proposed algorithm produces visually fine images with high PSNR.

• Journal of KIISE:Databases
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• v.30 no.3
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• pp.273-285
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• 2003

Generally, vector spatial data, with richer information than raster spatial data enabledata, enables a mere flexible and effective manipulation of the data sets. However, one of challenges against the publication of vector spatial information on the Internet is the efficient transmission of the big and complex vector spatial datadata, which is both large and complex, across the narrow-bandwidth of the Internet. This paper proposes a new transmission method, namely, the Scale-Dependent Transmission method, with the purpose of improving the efficiency of vector spatial data transmission on the narrow-bandwidthacross the Internet. Simply put, its nam idea is “Transmit what can be seen””. Scale is regarded as a factor naturally associated with spatial features so that not all features are visible to users at a certain scale. With the aid of the Wavelet-Wavelet-based Map Generalization Algorithm, the proposed method filters out invisible features from spatial objects according to the display scale and then to transmit onlytransmits only the visible features as athe final answer for an individual operation. Experiments show that the response times ofan individual operation has been reducedoperations were substantially by the usage of reduced when using the proposed method.

• Journal of the Korea Computer Graphics Society
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• v.25 no.3
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• pp.21-29
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• 2019

This paper proposes a novel framework for image fusion of satellite imagery to enhance spatial resolution of the image via structure-texture decomposition. The resolution of the satellite imagery depends on the sensors, for example, panchromatic images have high spatial resolution but only a single gray band whereas multi-spectral images have low spatial resolution but multiple bands. To enhance the spatial resolution of low-resolution images, such as multi-spectral or infrared images, the proposed framework combines the structures from the low-resolution image and the textures from the high-resolution image. To improve the spatial quality of structural edges, the structure image from the low-resolution image is guided filtered with the structure image from the high-resolution image as the guidance image. The combination step is performed by pixel-wise addition of the filtered structure image and the texture image. Quantitative and qualitative evaluation demonstrate the proposed method preserves spectral and spatial fidelity of input images.

• Proceedings of the Korea Water Resources Association Conference
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• 2003.05b
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• pp.695-698
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• 2003

No Abstract, See Full Text

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.185-188
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• 2000

본 논문은 인간이 양귀로 3차원 공간상의 음의 위치를 파악하는 원리를 이용하여 만들어진 입체음향을 청취자의 안귀에 가장 효과적으로 재생시킴으로써 완벽한 입체음향을 재현하는 장치로 3차원 게임, 가상현실 시뮬레이터, 놀이공원에서 사용될 수 있는 A/V용 입체음향 재생기 구현 기법이다. 본 개발 품은 전방 30도에 스피커를 배치하는 기존 제품에 비해 안정된 정면 음상 정위와 후면 음상 정위가 가능하고, 청취자의 머리 움직임에 따른 입체음향 효과의 저하를 막을 수 있으며, 인지적 특성을 고려한 역 필터링으로 과도한 신호처리로 인한 음질 저하를 개선할 수 있고, 다중 사용자에게 동일한 음질을 골고루 전달할 수 있어 카 오디오나 영화관에서도 사용되어질 수 있다.