• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.178-180
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• 2004

In this work, we propose new method of sigma filtering for efficient filtering and preserving edge regions in DCT Domain. In block-based image compression technique, the image is first divided into non-overlapping $8{\times}8$ blocks. Then, the two-dimensional DCT is computed for each $8{\times}8$ block. Once the DCT coefficients are obtained, they are quantized using a specific quantization table. Quantization of the DCT coefficients is a lossy process, and in this step, noise is added. In this work, we combine IDCT matrix and filter matrix to a new matrix to simplify filtering process to remove noise after IDCT in spatial domain, for each $8{\times}8$ DCT coefficient block, we determine whether this block is edge or homogeneous region. If this block is edge region, we divide this $8{\times}8$ block into four $4{\times}4$ sub-blocks, and do filtering process for sub-blocks which is homogeneous region. By this process, we can remove blocking artifacts efficiently preserving edge regions at the same time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4C
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• pp.505-513
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• 2004

Most video codecs including the international standards use the block-based hybrid structure for efficient compression. But for low bit-rate applications such as video transmission through wireless channels, the blocking artifacts degrade image qualify seriously. In this paper, we propose an adaptive de-blocking algorithm using characteristics of the block boundaries. Blocking artifacts contain the high frequency components near the block boundaries, therefore the lowpass filtering can remove them. However, simple lowpass filtering results into blurring by removing important information such as edges. To overcome this problem, we determine the modes depending upon the characteristics of pixels adjacent to block boundary then proper filter is applied to each area. Simulation results show that proposed method improves de-blocking performance compared to that of MPEG-4.

• Journal of Korea Multimedia Society
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• v.12 no.6
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• pp.867-875
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• 2009

More and richer information sources and services are available on the web everyday. However, harmful information, such as adult content, is not appropriate for all users, notably children. Since internet is a worldwide open network, it has a limit to regulate users providing harmful contents through each countrie's national laws or systems. Additionally it is not a desirable way of developing a certain system-specific classification technology for harmful contents, because internet users can contact with them in diverse ways, for example, porn sites, harmful spams, or peer-to-peer networks, etc. Therefore, it is being emphasized to research and develop context-based core technologies for classifying harmful contents. In this paper, we propose an efficient text filter for blocking harmful texts of web documents using context-based technologies and examine which algorithms for feature selection, the process that select content terms, as features, can be useful for text categorization in all content term occurs in documents, are suitable for classifying harmful contents through implementation and experiment.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.859-864
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• 2006

The openness of the Web allows any user to access almost any type of information easily at any time and anywhere. However, with function of easy access for useful information, internet has dysfunctions of providing users with harmful contents indiscriminately. Some information, such as adult content, is not appropriate for all users, notably children. Additionally for adults, some contents included in abnormal porn sites can do ordinary people's mental health harm. In the meantime, since Internet is a worldwide open network it has a limit to regulate users providing harmful contents through each countrie's national laws or systems. Additionally it is not a desirable way of developing a certain system-specific classification technology for harmful contents, because internet users can contact with them in diverse way, for example, porn sites, harmful spams, or peer-to-peer networks, etc. Therefore, it is being emphasized to research and develop context-based core technologies for classifying harmful contents. In this paper, we propose an efficient text filter for blocking harmful texts of web documents using context-based technologies.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.338-351
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• 2003

UV radiation is the most dangerous stress factor among permanent environmental impacts on human skin. Consequences of UV exposure are aberrant tissue architecture, alterations in skin cells including functional changes. Nowadays new kinds of outdoor leisure-time activities and changing environmental conditions make the question of sun protection more important than ever. It is necessary to recognize that self-confident consumers do not consider to change their way of life, they demand modern solutions on the basis of new scientific developments. In the past one fundamental principle of cosmetics was the use of physical and organic filter systems against damaging UV-rays. Today new research results demonstrate that natural protecting cell mechanisms can be activated. Suitable biological actives strongly support the protection function not from the surface but from the inside of the cell. A soy seed preparation (SSP) was proven to stimulate natural skin protective functions. The major functions are an increased energy level and the prevention of DNA damage. These functions can I be defined as biological UV protection. The tumor suppressor protein p53 plays a key role in the regulation of DNA repair. p53 must be transferred into the phosphorylated form to work as transcription factor for genes which are regulating the cell cycle or organizing DNA repair. A pretreatment with SSP increases the phosphorylation rate of p53 of chronically UV-irradiated human keratinocytes significantly. According to the same test procedure SSP induces a dramatic increase in the expression of the tumor suppressor protein p14$^{ARF}$ that is supporting the p53 activity by blocking the antagonist of p53, the oncoprotein Mdm2. Mdm2, a ubiquitin E3-ligase, downregulates p53 and at the same time it prevents phosphorylation of p53. The positive influence of the tumor suppressor proteins explains the stimulation of DNA repair and prevention of sunburn cell formation by SSP, which was proven in cell culture experiments. In vivo the increased skin tolerance against UV irradiation by SSP could be confirmed too. We have assumed, that an increased repair potential provides full cell functionality.y.