• Journal of Broadcast Engineering
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• v.21 no.6
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• pp.845-860
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• 2016

This paper proposes a digital watermarking scheme to protect the ownership of the freeview 2D or 3D image such that the viewer watches the image(s) by rendering a arbitrary viewpoint image(s) with the received texture image and its depth image. In this case a viewpoint change attack essentially occurs, even if it is not malicious. In addition some malicious attacks should be considered, which is to remove the embedded watermark information. In this paper, we generate a depth variation map (DVM) to find the locations less sensitive to the viewpoint change. For each LH subband after 3-level 2DDWT for the texture image, the watermarking locations are found by referring the DVM. The method to embed a watermark bit to a pixel uses a linear quantizer whose quantization step is determined according to the energy of the subband. To extract the watermark information, all the possible candidates are first extracted from the attacked image by considering the correlation to the original watermark information. For each bit position, the final extracted bit is determined by a statistical treatment with all the candidates corresponding that position. The proposed method is experimented with various test images for the various attacks and compared to the previous methods to show that the proposed one has excellent performance.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.130-133
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• 2010

멀티미디어 신호 처리 분야의 급속한 발전으로 인해 3차원 TV(3DTV)는 차세대 방송 시스템 시장에서 가장 주목을 받는 제품이 되었다. 3DTV는 사용자에게 입체감을 제공하여 사용자가 마치 그곳에 있는 듯한 효과를 줄 수 있다. 이에 최근 다시점 컬러 영상과 그에 대응되는 깊이 영상을 이용하여 다양한 위치에서의 입체 영상을 제공하는 기술이 활발히 진행되고 있다. 본 논문에서는 주어지는 다시점 컬러 영상과 깊이 영상의 정보를 동시에 이용하여 다시점 영상 부호화의 효율을 높이는데 그 목적이 있다. 이를 위해 시점 생성 기법을 통해 다시점 영상의 부호화 시 참조하는 주변 시점의 영상들로부터 계산되는 변이 벡터 정보를 줄이는 방법을 제안한다. 실험 결과, 기존의 다시점 비디오 부호화에 비해서 약 0.5~1.5 dB정도의 화질 개선이 이뤄졌고, 평균 17.5%의 비트율 감소를 보였다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.155-164
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• 2004

Advanced spent fuel Conditioning Process(ACP) project which is under development for efficient spent fuel management has finished process feasibility study and is preparing $\alpha$-${\gamma}$ type hot cell construction for process experimentation. Radiation dose evaluation for the radioactive nuclides were preliminarily performed for normal operation and accident case with the basic concept design report, the meteorological data and the recent site specific data. According to the production and release rate of nuclides, dose evaluations for residents around facility were performed. The evaluation result shows a safe margin for regulation limits and SAR(Safety Analysis Report) limit of IMEF(Irradiated Material Examination Facility) where this facility will be constructed.

• Journal of Digital Convergence
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• v.21 no.3
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• pp.41-48
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• 2023

As the 4th Industrial Revolution accelerates, the future of the economy faces new uncertainties, particularly around digital transformation. This shift is crucial in today's ICT-centric world. Korea, a significant contributor to global Manufacturing Value Added (MVA), is poised to expand its share. This paper examines Korea's digital transformation and its global economic competitiveness. By referencing world-renowned analyses, it compares Korea's competitive stance. As industries and economies are on the verge of a technological upheaval, understanding and preparing for these changes is vital for maximizing benefits. This paper also delves into the opportunities and policy challenges presented by digitization in the 4th Industrial Revolution era.

• Journal of KIISE
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• v.44 no.6
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• pp.643-648
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• 2017

Among Wi-Fi based indoor positioning systems, fingerprinting localization is the most common technique with high precision. However, construction of the initial radio map and the update process require considerable labor and time effort. To address this problem, we propose an efficient method that constructs the initial radio map at each vertex based on a graph. In addition, we introduce a method to update the radio map automatically by mapping signal data acquired from users to the reference point created on each edge. Since the proposed method collects signal data manually only at the vertex of the graph to build the initial radio map and updates it automatically, our proposed method can dramatically reduce labor and time effort, which are the disadvantages of the conventional fingerprinting method. In our experimental study, we show validity of our radio map update method by comparing with the actual reference point data. We also show that our proposed method is able to construct the radio map with an accuracy of about 3.5m by automatically updating the radio map.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.76-83
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• 2009

This paper presents a compression method for animated meshes or mesh sequences which have a shared connectivity and geometry streams. Our approach is based on static semi-regular mesh compression algorithm introduced by Khodakovky et al. Our encoding algorithm consists of two stages. First, the proposed technique creates a semi-regular mesh sequence from an input irregular mesh sequence. For semi-regular remeshing of irregular mesh sequences, this paper adapts the MAPS algorithm. However, MAPS cannot directly be performed to the input irregular mesh sequence. Thus, the proposed remesh algorithm revises the MAPS remesher using the clustering information, which classify coherent parts during the animation. The second stage uses wavelet transformation and clustering information to compress geometries of mesh sequences efficiently. The proposed compression algorithm predicts the vertex trajectories using the clustering information and the cluster transformation during the animation and compress the difference other frames from the reference frame in order to reduce the range of 3D position values.

• Spatial Information Research
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• v.21 no.3
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• pp.31-43
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• 2013

Although the vector map data possesses much higher values than other types of multimedia, the data copyright and the protection against illegal duplication are still far away from the attention. This paper proposes a novel watermarking technique which is both robust to diverse attacks and optimized to a vector map structure. Six approaches are proposed for the design of the watermarking algorithm: point-based approach, building a minimum perimeter triangle, watermark embedding in the length ratio, referencing to the pixel position of the watermark image, grouping, and using the one-way function. Our method preserves the characteristics of watermarking such as embedding effectiveness, fidelity, and false positive rate, while maintaining robustness to all types of attack except a noise attack. Furthermore, our method is a blind scheme in which robustness is independent of the map data. Finally, our method provides a solution to the challenging issue of degraded robustness under severe simplification attacks.

• Journal of Broadcast Engineering
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• v.19 no.1
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• pp.83-95
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• 2014

Hand posture recognition is an important technique to enable a natural and familiar interface in HCI(human computer interaction) field. In this paper, we introduce a hand posture recognition method by using a depth camera. Moreover, the hand posture recognition method is incorporated with MPEG-U based advanced user interaction (AUI) interface system, which can provide a natural interface with a variety of devices. The proposed method initially detects positions and lengths of all fingers opened and then it recognizes hand posture from pose of one or two hands and the number of fingers folded when user takes a gesture representing a pattern of AUI data format specified in the MPEG-U part 2. The AUI interface system represents user's hand posture as compliant MPEG-U schema structure. Experimental results show performance of the hand posture recognition and it is verified that the AUI interface system is compatible with the MPEG-U standard.

• Journal of the Korea Computer Graphics Society
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• v.13 no.1
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• pp.33-36
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• 2007

Generally, word balloon have played a role to connect the script with character in comics. The location of word balloons depicts the process of story in comics, because they are located by reading order. Therefore, it is very Important works to generate and place word balloons, these work usually is processed manually by comic writer's. In this paper, we discuss the automated generation and placement of word balloon. For this, we modeled 6 kinds of word balloons. And these word balloons are placed by heuristic method based on EPFLP. We also generate the tail of word balloon automatically by considering the direction and reference points of word balloon.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.635-635
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• 2012

최근 공공분야 및 민간분야에서 고해상도 위성영상의 활용이 높아짐에 따라 이를 이용하여 수자원 분야의 치수계획 및 안전도 평가, 유역 홍수대응기술 분야에서의 다양한 활용이 비약적으로 증대되고 있는 실정이다. 고해상도 위성영상의 활용은 국지적 규모의 토지이용 변화 및 대기 상태의 모니터링을 위한 효과적인 기술로 인식되어 왔다. 우리나라의 KOMPSAT-2 위성은 GSD(Ground Sample Distance) 1m급의 전정색 영상과 4m급의 다중분광 영상을 동시에 제공하는 고해상도 위성이다. 그러나 다중분광센서의 복잡성과 보안성에 의해 영상이 제한적으로 제공되고 있어 KOMPSAT-2 위성영상을 이용한 다양한 연구가 미흡한 실정이다. 한편, 토지이용도의 제작은 다중분광 영상을 제공하는 위성영상을 이용하여 제작된다. 다중분광 영상이 제공하는 분광정보 및 공간정보 등으로 토지이용분류를 수행하거나 멀티센서 자료의 통합을 통한 토지이용분류 기법을 개발하여 제작하였다. 그러나 대부분 GSD 10m급 이상의 중 저해상도 위성영상을 이용하여 제작이 이루어져 수평위치 정확도 및 세부정보의 제공이 낮으며, 정보의 최신성이 결여되어 있다. 특히, 유역 치수안전도 평가를 위한 토지이용도 작성은 매우 중요한 부분을 차지하고 있으므로 이에 대한 연구가 필요하다. 이에 본 연구에서는 섬강유역을 대상으로 KOMPSAT-2 영상을 이용하여 유역 치수안전도 평가 및 치수계획 수립기술을 위한 토지이용도를 작성하고자 한다. 토지이용 분류방법은 감독분류와 무감독분류 방법을 조합하여 분류정확도를 개선시키는 하이브리드분류(hybrid classification) 방법을 이용하였으며, 분류기준의 선정은 환경부 토지이용분류 기준을 참고하여 1단위와 2단위 분류체계를 혼용하였다. 또한, 분류 후 후처리를 통하여 잡음을 제거하고 환경부의 토지이용도를 참조하여 육안판독으로 오분류된 지역을 보정하였다. 새롭게 작성된 토지이용도는 기존의 토지이용도와 비교 분석하여 토지이용변화 상황을 파악하고, 이를 통하여 KOMPSAT-2 영상의 토지이용도 개선 가능성을 검토하였다.