• Journal of Broadcast Engineering
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• v.6 no.1
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• pp.41-49
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• 2001

Digital watermarking has been proposed for copyright protection of digital data. According to the property of an embedded watermark, it is classified into two categories, robust watermarking and fragile watermarking. The former is used for copyright protection, and the latter applies to the authentication/integrity to verify the authenticity of data, If an Image has been modified or forged. the embedded watermark cannot be extracted from the Image. As a results, it is possible to defect the modification of the image. As pixels are represented by tilts, the modification of bits corresponds to the alteration of the image. In this paper, a new fragile watermarking is proposed In which two watermarks are embedded in order to detect some modification occurred In high and low bit Planes. From simulation results, the embedded watermark is Invisible in a watermarked image and we can locale some Places where the modification occurring

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.215-217
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• 2008

The most widely used method for searching contents of mot ion picture compares contents by extracted cuts. The cut extract ion methods, such as CHD(Color Histogram Difference) or ECR(Edge Change Ratio), are very weak at modifications such as cropping, resizing and low bit rate. The suggested method uses audio contents for indexing and searching to make search be robust against these modification. Scenes of audio contents are extracted for modification-robust search. And based on these scenes, make spectral powers binary on each frequency bin. in the time-frequency domain. The suggested method shows failure rate less than 1% on the false positive error and the true negative error to the modified(using cropping, clipping, row bit rate, addtive frame) contents.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.579-587
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• 2008

Typically, the file sizes of JPEG compressed images with various complexity differ from images regardless of same image size. So, it is not easy to estimate the remaining image counts that should be stored in the limited storage equipped with the digital camera. To solve the problem, the bit rate control employs the modification of quantization table. The previous work assumed that there is linear relation between image activity and modification factor of quantization table, but in this paper, more accurate functional relations based on statistics are employed to improve the bit rate control accuracy. Computer simulations reveals that the standard deviation of the bit rate error of the proposed scheme is 50% less than that of the conventional method.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.480-484
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• 2005

In this paper, the multiwatermarking method to make it possible to the authentication, modification detection and copyright protection of the digital image was proposed. After the original image is transformed by the DWT(Discrete Wavelet Transform), the encrypted watermark information is embedded into the LSB(Least Significant Bit) of LL band on the low frequence domain for authenticating and detecting modified position in the image. And watermark information is embedded by exchanging the wavelet coefficient for the copyright protection. Thereby, we can authenticate the modification and detect the modified location by extracting the values of LSB on the low frequence domain. And we can perceive the copyright information of original image by extracting the embedded watermark on the high frequence domain.

• The Journal of the Korea Contents Association
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• v.6 no.1
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• pp.170-178
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• 2006

In this paper, the hybrid-watermarking method to make it possible to the authentication, modification detection and copyright protection of the digital image was proposed. After the original image is transformed by the DWT(Discrete Wavelet Transform), the encrypted watermark information is embedded into the LSB(Least Significant Bit) of LL band on the low frequence domain for authenticating and detecting modified position in the image. And watermark information is embedded by exchanging the wavelet coefficient for the copyright protection. Thereby, we can authenticate the modification and detect the modified location by extracting the values of LSB on the low frequence domain. And we can perceive the copyright information of original image by extracting the embedded watermark on the high frequence domain.

• Journal of Broadcast Engineering
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• v.22 no.5
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• pp.618-631
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• 2017

In this paper, we propose a modification of fuzzy logic based DASH adaptation algorithm(FDASH) for seamless media service in time-varying network conditions. The proposed algorithm selects more appropriate bit-rate for the next segment by the modification of the Fuzzy Logic Controller(FLC) and reduces the number of video bit-rate changes by applying Segment Bit-rate Filtering Module(SBFM). Also, we apply the Start Mechanism for clients not to watch the low quality videos in the very beginning stage of streaming service and add the Sleeping Mechanism to avoid any buffer overflow expected. Ultimately, we verified by using NS-3 Network Simulator that the proposed method shows better performance compared to FDASH. According to the experimental results, there is no buffer underflow/overflow within the limited buffer size, which is not guaranteed in FDASH on the other hand. Also, we confirmed that mFDASH has almost the same level of average video quality against FDASH and reduces about 50% of number of video bit-rate changes compared to FDASH in Point-to-Point network and Wi-Fi network.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.863-866
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• 1998

In this paper, we proposes Moving Picture Compression reducing bit numbers within the block by probability in 3D-DCT considered of temporal axis. From Delta Modification theory for frequency components, bit numbers within the block(4$\times$4) were properly compressed by using the Probability Entropy. At the result for the proposed algorithm, we could find that the values of PSNR for resolution and the compression rate were better than existing methods.

• Journal of the Korean Institute of Intelligent Systems
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• v.2 no.2
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• pp.42-60
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• 1992

An adaptive fuzzy system can efficiently classify subimages into four categories according to image activity level for image data compression. The system estimates fuzzy rules by clustering input-output data generated from a given adaptive transform image coding process. The system encodes different images without modification and reduces side information when encoding multiple images. In the second part, a fuzzy system estimates optimal bit maps for the four subimage classes in noisy channels assuming a Gauss-Markov image model. The fuzzy systems respectively estimate the sampled subimage classification and the bit-allocation processes without a mathematical model of how outputs depend on inputs and without rules articulated by experts.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.35-38
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• 2000

Low bit rate image/video coding is essential for many visual communication applications. When bit rates become low, most compression algorithms yield visually blocking artifacts that highly degrade the perceptual quality, and post-processing approaches provide one attractive solution. In this paper, we provide simple and very efficient blocking artifacts reduction method using constrained random value addition. Our method is simple enough to be used for real-time post-processing of video.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.5
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• pp.37-42
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• 2012

Audio steganography is quite similar to the procedure of modifying the least significant bit(LSB) of image media files. The most widely used technique today is hiding of secret messages into a digitized audio signal. In this paper, I propose a new method for hiding messages from attackers, high data inserting rate is achieved. In other words, based on the LSB hiding method and digitized to change the bit position of a secret message, an encrypted stego medium sent to the destination in safe way.