• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.231-234
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• 2001

In this paper, we present a robust watermarking technique based on a DCT-domain watermarking approach and an order statistic(OS) filter. The proposed technique inserts one watermark into each of four coefficients within a 2 ${\times}$ 2 block which is scanned on DCT coefficients in the zig-zag ordering from the medium frequency range. The detection algorithm uses an adaptive trimmed mean operator as a local estimator of the embedded watermark to obtain the desired robustness in the presence of additive Gaussian noise and JPEG compression attacks. The performance is analyzed through statistical analysis and numerical experiments. It is shown that the robustness properties against additive noise and JPEG compression attacks are more enhanced than the previous techniques.

• Journal of the Korean Graphic Arts Communication Society
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• v.21 no.1
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• pp.35-44
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• 2003

Because of computer developing, the digital image making the use of many a field of application with - web-above, electronic publishing. printing, dynamic image management and photo CD production etc., however many problems of save and management. The management image use of compression moth which don't have a affect on image, reduce file size. A study used sequential DCT0based mode and progressive DCT-based mode of JPEG(Joing Photographic Experts Group) compression method and Wavelet compression method. Therefore, the analog image and digital image was changed and applied by several stages according to compression rate. It made inquiries of the optimum compression rate that be compared quality transformation between original image and compressed image. As compression image was printing simply, the quality was studied by subjective valuation method, that was studied propriety and usefulness.

• English Language & Literature Teaching
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• v.17 no.1
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• pp.53-80
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• 2011

The study examines how Koreans' politeness is realized in a speech act, request. The main focus is to explore underlying rationale and influence involved in their performance, not just the comparison of difference in politeness realization between native and nonnative speakers of English, as previous studies did. The study employs the DCT, an attached politeness scale questionnaire, and interviews. Twenty nine university students participated in the study. Interchangeable reading of the three data yields some interesting and valuable insights. The participants heavily rely on a few formulaic expressions to express politeness, such as interrogatives with modal verbs, please and excuse me as a politeness marker. They want to use honorific address terms that is literally translated into English, and have a belief that there are honorific words in English as in Korean. The study refers to the participants' voice on indirectness, nonverbal messages, and expressions with different connotations between English and Korean.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.392-397
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• 2000

An Interlaced 2D field images compression technique by Discrete Wavelet Transform is proposed. The result has a good image resolution and compression rate, PSNR, and reduces processing time of compression. PSNR depends on the exponential function corresponding to 2 power N has higher 30% than DCT. And It is easier to process the inter-frame and fast to work a second with each parallel field processing, and more be able to approximate a frame on the field.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.3
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• pp.54-62
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• 2008

For a message hiding technique to be effectual, it needs to have availability, confidentiality and integrity. Steganography is the science of hiding one message within other types of digital contents. In this case, attempt to defeat steganalysis by restoring the statistics of the composite image to resemble that of the cover, these discrepancies expose the fact that hidden communication is happening. In this paper, I present a steganography scheme capable of concealing a piece of secrete information in a host image and base on the technique's OCT, RGB, statistical restoration.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.1
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• pp.15-20
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• 2002

The frame coding inside the screen for a video coder has a big influence on the quality of the whole frame. The standardized video coder uses DCT, however it can give rise to a low image quality due to the blocking effect at low bit rate. This paper proposes a video coding method for an image quality improvement in human visual aspects. With the proposed method, the perceptual weight is coded with SPIHT and VLC by applying it into the frame and the visual noises are eliminated.

• Journal of Korea Multimedia Society
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• v.10 no.11
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• pp.1427-1438
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• 2007

Video watermarking technologies are classified into types of four kinds. The first type is to embed the watermark into a raw video signal and to code the watermarked video signal. Most of video watermarking technologies fall into the category of this type. The second type is to apply watermarking to the coding process, such as block DCT and quantization. The third is to directly embed the watermark into the compressed bitstream itself. Generally, it is referred as labelling rather than watermarking. Finally, the fourth is to embed the water mark into MPEG motion vector. This type has the difficulty in real-time process because of the high complexity and has the blocking effects because of DCT-based on coder. In this paper, we proposed the digital video watermarking that embed the watermark in SPIHT video code for I-frame using motion vector analysis. This method can remove the blocking effect occurred at the DCT-based on coder and obtain video data that has progressive transmission property. The proposed method is to select the region for the watermark embedding in I frame using motion vector estimated from the previous P or B frame. And then, it is to perform DWT and embed the watermark based on HVS into the wavelet coefficients in the same subband of DWT as the motion vector direction. Finally, the watermarked video bitstream is obtained by the SPIHT coder. The experimental results verified that the proposed method has the invisibility from the objective and subjective image quality and the robustness against the various SPIHT compression and MPEG re-code.

• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.200-208
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• 2016

Compressed sensing is a signal processing technique for efficiently acquiring and reconstructing in an under-sampled (i.e., under Nyquist rate) representation. A block compressed sensing with projected Landweber (BCS-SPL) framework is most widely known, but, it has high computational complexity at decoder side. In this paper, by introducing adaptive exit criteria instead of fixed exit criteria to SPL framework, an effective fast algorithm is designed in such a way that it can utilize efficiently the sparsity property in DCT coefficients during the iterative thresholding process. Experimental results show that the proposed algorithm results in the significant reduction of the decoding time, while providing better visual qualities than conventional algorithm.

• English Language & Literature Teaching
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• v.13 no.3
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• pp.77-97
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• 2007

To compare data on the speech act of requests from two different methods, a study was conducted in which both native and non-native speakers of English participated as subjects, and data were collected by means of actual e-mail writing and DCT (discourse completion test). The analysis of requests from the two different data-gathering methods showed that despite some similarities, considerable differences existed between e-mail and DCT requests in several important aspects of requests such as amount of talk, directness level, downgraders and supportive moves which play an important role in making a given request sound less imposing and more polite. Also it was shown that requests of non-native speakers differed considerably from requests of native speakers in terms of the four aspects of requests across type of data-gathering methods. Based on the findings, some suggestions were made for both further research and L2 classrooms.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.3
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• pp.29-36
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• 2015

Steganography is the technique of hiding the existence of a secret message that is communicated hiddenly. Generally, the main objectives of this paper is to develop newer and more sophisticated steganographic techniques based on perceptual transparency, robustness and capacity of the hidden data. This paper analyzes the advantages and disadvantages of image steganography techniques and proposes an effective method. As a result, the images steganography technique based on good ELSB and DCT which applies the rearranged key is secure and effective.