• International Journal of Advanced Culture Technology
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• v.7 no.4
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• pp.242-245
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• 2019

In this paper, watermark embedding technique was proposed to securely conceal the watermark in color cover image by applying the spatial encryption technique. The embedded watermak can be extracted from stego-image without loss. The quality of the stego-image is very good. So it is not possible to visually distinguish the difference between the original cover image and the stego-image. The validity of the proposed technique was verified by mathematical analysis. The proposed watermark embedding technique can be used for intellectual property protection, military, and medical applications that require high security.

• Spatial Information Research
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• v.17 no.4
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• pp.405-416
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• 2009

According to the changes of the city's paradigm, the demand on u-City increases rapidly. u-City has been built at 54 areas in Korea (as of May 2009). One of the important determinants of success or failure in the increasing of u-City is how to provide u-Services. Most current u-Services are Sensor Network-based monitoring services to manage urban infrastructure. u-GIS is one of fundamental requirements to implement 'any time and any where' u-Service which covers the essential meaningful term "ubiquitous". Hence, in this paper, we 1) describe the definition of the spatial awareness, 2) discuss how to converge (Spatial Embedding) among different spatial data : topographic spatial data, sensor spatial data, and more, 3) bring forth an advanced form of u-Service, 4) analyze the state-of-the-art u-GIS techniques.

• Journal of Korea Multimedia Society
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• v.25 no.10
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• pp.1535-1545
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• 2022

Sign language has completely different meaning depending on the direction of the hand or the change of facial expression even with the same gesture. In this respect, it is crucial to capture the spatial-temporal structure information of each movement. However, sign language translation studies based on Sign2Gloss2Text only convey comprehensive spatial-temporal information about the entire sign language movement. Consequently, detailed information (facial expression, gestures, and etc.) of each movement that is important for sign language translation is not emphasized. Accordingly, in this paper, we propose Spatial-temporal Keypoints Centered Sign2Gloss2Text Translation, named STKC-Sign2 Gloss2Text, to supplement the sequential and semantic information of keypoints which are the core of recognizing and translating sign language. STKC-Sign2Gloss2Text consists of two steps, Spatial Keypoints Embedding, which extracts 121 major keypoints from each image, and Temporal Keypoints Embedding, which emphasizes sequential information using Bi-GRU for extracted keypoints of sign language. The proposed model outperformed all Bilingual Evaluation Understudy(BLEU) scores in Development(DEV) and Testing(TEST) than Sign2Gloss2Text as the baseline, and in particular, it proved the effectiveness of the proposed methodology by achieving 23.19, an improvement of 1.87 based on TEST BLEU-4.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.7
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• pp.1030-1040
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• 1998

One of the main unresolved issues in large-eddy simulation(LES) of wall-bounded turbulent flows is the requirement of high spatial resolution in the near-wall region, especially in the spanwise direction. Such high resolution required in the near-wall region is generally used throughout the computational domain, making simulations of high Reynolds number, complex-geometry flows prohibitive. A grid-embedding strategy using a nonconforming spectral domain-decomposition method is proposed to address this limitation. This method provides an efficient way of clustering grid points in the near-wall region with spectral accuracy. LES of transitional and turbulent channel flow has been performed to evaluate the proposed grid-embedding technique. The computational domain is divided into three subdomains to resolve the near-wall regions in the spanwise direction. Spectral patching collocation methods are used for the grid-embedding and appropriate conditions are suggested for the interface matching. Results of LES using the grid-embedding strategy are promising compared to LES of global spectral method and direct numerical simulation. Overall, the results show that the spectral domain-decomposition grid-embedding technique provides an efficient method for resolving the near-wall region in LES of complex flows of engineering interest, allowing significant savings in the computational CPU and memory.

• Journal of KIISE
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• v.44 no.1
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• pp.71-77
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• 2017

There has been a recent spate in the usage of mobile device equipped GPS sensors, such as smart phones. This trend enables the posting of geo-tagged messages (i.e., multimedia messages with GPS locations) on social media such as Twitter and Facebook, and the volume of such spatial data is rapidly growing. However, the relationships between the location and content of messages are not always explicitly shown in such geo-tagged messages. Thus, the need arises to reorganize search results to find the relationship between keywords and the spatial distribution of messages. We find the smallest minimum bounding rectangle (MBR) that embedding k or more points in order to find the most dense rectangle of data, and it can be usefully used in the location search system. In this paper, we suggest efficient algorithms to discover a group of 2-Dimensional spatial data with a close distance, such as MBR. The efficiency of our proposed algorithms with synthetic and real data sets is confirmed experimentally.

• Journal of Broadcast Engineering
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• v.6 no.2
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• pp.169-176
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• 2001

Most of the previous video watermarking algorithms cannot be supported by real-time video processing. The maul reason is that in order to develop a robust algorithm the watermarking technique requires a very high computational cost when embedding and extracting the watermark in various frequency domains. Previous embedding methods simultaneously try to compress a video by MPEG and embed a watermark supporting real-time processing. However, In this paper, our proposed algorithm can support real-time processing in both spatial and frequency domains. First. the watermark is created on the courier transform domain, and next is inverse-Fourier-transformed ; then, we directly embed it into the video frame In the spatial domain. This procedure does not require a lot of the computational cost during embedding because of the spatial domain processing. Also, it is possible to support a video stream service and a very robust algorithm from MPEG compression and various geometric attacks.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.801-810
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• 2011

This paper proposes a new lossless data embedding algorithm on spatial domain of digital images. A single key parameter is required to embed and extract data in the algorithm instead of embedding any additional information such as the location map. A $3{\times}3$ window slides over the cover image by one pixel unit, and one bit can be embedded at each position of the window. So, the ideal embedding capacity equals to the number of pixels in an image. For further increase of embedding capacity, new weight parameters for the estimation of embedding target pixels have been used. As a result, significant increase in embedding capacity and better quality of the message-embedded image in high capacity embedding have been achieved. This algorithm is verified with simulations.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.1
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• pp.22-28
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• 2008

In this paper, we propose a DCT coefficient domain watermarking scheme, which makes use of the sinusoidal patterns created by the watermark embedding. The embedded watermark can be detected in the spatial domain by computing the correlation. Also, the proposed algorithm can detect the spatial synchronization without additional sync bit embedding. Experimental results show that the proposed algorithm is robust to various StirMark attacks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2741-2761
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• 2017

With the purpose of copyright protection for digital video, a novel H.264/AVC watermarking algorithm based on JND model is proposed. Firstly, according to the characteristics of human visual system, a new and more accurate JND model is proposed to determine watermark embedding strength by considering the luminance masking, contrast masking and spatial frequency sensitivity function. Secondly, a new embedding strategy for H.264/AVC watermarking is proposed based on an analysis on the drift error of energy distribution. We argue that more robustness can be achieved if watermarks are embedded in middle and high components of $4{\times}4$ integer DCT since these components are more stable than dc and low components when drift error occurs. Finally, according to different characteristics of middle and high components, the watermarks are embedded using different algorithms, respectively. Experimental results demonstrate that the proposed watermarking algorithm not only meets the imperceptibility and robustness requirements, but also has a high embedding capacity.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.3
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• pp.262-266
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• 2020

In this paper, we proposed an effective technique for hiding the watermark in the LSB of a color image by applying spatial encryption techniques. Even if the watermark hidden in the LSB of the image is extracted, the information of the extracted watermark cannot be decrypted because the watermark is encrypted using various spatial encryption techniques. Therefore, if the watermark is concealed in the LSB using the spatial encryption techniques proposed in this paper, the security is greatly improved compared to the existing technique of embedding the watermark in the LSB. When watermarking is performed by applying the proposed technique, the image quality of the watermark-concealed image is very good, so it is impossible to distinguish it from the original image, and the watermark, which is confidential data, can be extracted from the watermarked image without loss. The performance of the proposed technique was mathematically analyzed and the superiority of the proposed technique was confirmed through experiments. When the watermark was concealed by applying the proposed technique to Lenna, airplane, Tiffany, and pepper images having a size of 512×512, the PSNR values of the watermarked images were 53.91dB, 54.10dB, 54.09dB, and 54.13dB, respectively.