• Convergence Security Journal
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• v.12 no.2
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• pp.107-113
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• 2012

Recently, according to the establishment of personal information protection Act, the public and private organizations are taking a step to protect personal information rights and interests by employing the technical methods such as the access control mechanism, cryptography, etc. The result of the personal information leakage causes a serious damage for the organization image and also has to face with the responsibility by law. However, applying access control and cryptographic approach on the personal information item for every connection to large database system causes significant performance degradation in a large database system. In this paper, we designed and implemented the light weight system using JVM (Java Virtual Machine) for the Oracle DBMS environment which the concurrent transaction occurs many, thereby the proposed system provides the minimum impact on the system performance and meets the need of personal information protection. The proposed system was validated on the personal information protection system which sits on a 'A' public organization's portal site and personnel information management system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2342-2348
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• 1999

DCT-based codebook design using binary tree was proposed to reduce computation time and to solve the initial codebook problem. In this method, DCT coefficient of training vectors that has maximum variance is to be a split key and the mean of coefficients at the location is used as split threshold, then balanced binary tree for final codebook is formed. However edge degradation appears in the reconstructed image, since the blocks of shade region are frequently selected for codevector. In this paper, we propose DCT-based vector quantization codebook design using unbalanced binary tree. Above all, the node that has the largest split key is splited. So the number of edge codevector can be increased. From the simulation results, this method reconstructs the edge region sincerely and shows higher PSNR than previous methods.

• The KIPS Transactions:PartB
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• v.12B no.7 s.103
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• pp.755-760
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• 2005

To transmit a video bit stream over low bandwith, such as mobile, channels, encoding algorithms for high bit rate like H.263+ are used. In transmitting video bit-streams, packet losses cause severe degradation in image quality. This paper proposes a new algorithm for the recovery of missing or erroneous motion vectors when H.263+ bit-stream is transmitted. Considering that the missing or erroneous motion vectors are closely related with those of neighboring blocks, this paper proposes a temporal-spatial error concealment algorithm. The proposed approach is that missing or erroneous Motion Vectors(MVs) are recovered by clustering the movements of neighboring blocks by their homogeneity. MVs of neighboring blocks we clustered according to ALA(Average Linkage Algorithm) clustering and a representative value for each cluster is determined to obtain the candidate MV set. By computing the distortion of the candidates, a MV with the minimum distortion is selected. Experimental results show that the proposed algorithm exhibits better performance in subjective and objective evaluation than existing methods.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.5
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• pp.598-606
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• 2002

We suggest a distributed communication and management methodology using PC to PC Query multicasting strategy for efficient management of medical images produced by DICOM(Digital Imaging and Communications in Medicine) Modalities. It is absolutely necessary to reduce strict degradation of PACS system due to large sire of medical images and their very high transport rates. DICOM PC to PC Component is composed of a Service Manager to execute requested queries, a Communication Manager to take charge of file transmission, and a DICOM Manager to manage stored data and system behavior Each Manager itself is a component to search for requested file by interaction or to transmit the file to other PCs. Distributed management and transformation of medical information based on PC to PC Query multicasting methodology will enhance performance of central server and network capacity, reducing overload on both. We organize three major components for system operation. Each component is implemented as Agent. Communication between agents uses XML encoded Agent Communication Language.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.241-246
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• 2004

Medical images are being managed more by PACS in general medical institutions. It is important to protect patients from being invaded their privacy related to the images. It is also necessary to confirm the ownership, the right of properity of the medical images and notice whether the data are modified. In this paper, we propose a robust watermarking against RST attacks in medical images on the PACS. The proposed scheme modifies and improves Log-Polar Mapping and Fourier Mellin Transform in order to realize and recover serious image degradation and watermark data loss caused by the conversion between cartesian coordinate and log-polar coordinate. We used the radius and theta Look Up Table to solve the realization of the Fourier Mellin Transform, and inserted a watermark into 2D-DFT magnitudes using Spread Spectrum. Experimental results shows that this method are robust to several attack.

• 보존과학연구
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• s.19
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• pp.3-22
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• 1998

The effect of pH on degradation of paper by some fungi, which able to degrade cellulose, was investigated. Trichoderma koningii, Aspergillus nigerand Penicillium nigulosum were cultured at $28^{\circ}C$ for 16 days in the selective medium (PH3, PH4, PH5, PH6, PH7, PH8, PH9, PH10, PHC) containing paper as substrate. Each paper was pretreated with each pH buffer (pH 3∼pH 10, D.W.)prior to addition to the selective medium. Enzyme activities in the each culture medium were measured spectroph to metrically using C.M.C., Avicel, PNPG as the substrates for endoglucanase, exoglucanase and $\beta$-glucosidase, respectively. In all experimental fungi, the enzyme activities of PH3 and PH9 medium were usually much higher than those of other experimental groups. However in the PH6medium, enzyme activity was lower than other groups. To analyze the concentration and pattern of protein in the each culture medium, the medium was concentrated by lyophilization. The protein concentration of PH3 and PH9 medium were relatively high (T.koningii; 6.31mg, 6,19mg, A.niger; 1.62mg, 1.96mg, P.nigulosum;2.50mg, 2.73mg, respectively), but that of PH6 was relatively low. The protein pattern of each medium was analyzed by using SDS-PAGE and VDS Image Master Analysis Program. The concentrations of bands in the each lane were usually high at lane2 (PH3) and lane8 (PH9) and low at lane5 (PH6). Therefore, the incresed cellulolytic activity of fungus against acidified paper could be result of structural change and deterioration of paper caused by being acidified.

• Journal of Korea Multimedia Society
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• v.9 no.5
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• pp.542-553
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• 2006

Because Y and C signals in a composite video signal are piled one on another in the same frequency, it is impossible to separate them completely. Therefore, it is necessary to develop efficient separation technique in order to minimize degradation of video quality. In this paper, we propose wavelet-based 3D comb filter algorithm and architecture for separating Y and C signals from a composite video signal. The proposed algorithm uses wavelet transform and thresholding of compared lines for acquiring the maximum video quality. Simulation results show that the proposed algorithm has better image quality and better PSNR than previous algorithms. For real application of the proposed algorithm, we developed a hardware architecture and the architecture was implemented by using VHDL. Finally, a VLSI layout of the proposed architecture was generated by using 0.25 micrometer CMOS process.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.837-842
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• 2008

Any errors that are generated in the channels and networks distort the video quality and are propagated in both the spatial and temporal domains. In particular, header errors ran result in serious visual degradation of the output video encoding/decoding schemes that can make an error resilient compressed bit-stream in error prone environments, such as mobile networks. In this paper, we proposes an header error resilience method that consider the activity of macroblock in video bitstream syntex. The extract of header error repaetedly embeds the header parameters into the least significant bits(LSB) of the quantized DCT coefficients prior to VLC. Experimental results show that the proposed error resilience method restores good image quality despite the detected error on header parameters.

• The Journal of Korean Institute of Information Technology
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• v.17 no.9
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• pp.99-112
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• 2019

Cracks on pavement surfaces are critical signs and symptoms of the degradation of pavement structures. Image-based pavement crack detection is a challenging problem due to the intensity inhomogeneity, topology complexity, low contrast, and noisy texture background. In this paper, we address the problem of pavement crack detection and segmentation at pixel-level based on a Deep Neural Network (DNN) using gray-scale images. We propose a novel DNN architecture which contains a modified U-net network and a high-level features network. An important contribution of this work is the combination of these networks afforded through the fusion layer. To the best of our knowledge, this is the first paper introducing this combination for pavement crack segmentation and detection problem. The system performance of crack detection and segmentation is enhanced dramatically by using our novel architecture. We thoroughly implement and evaluate our proposed system on two open data sets: the Crack Forest Dataset (CFD) and the AigleRN dataset. Experimental results demonstrate that our system outperforms eight state-of-the-art methods on the same data sets.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1189-1198
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• 2021

When performing remote tasks using robots in nuclear power plants, a 3D shape measurement system is advantageous in improving the efficiency of remote operations by easily identifying the current state of the target object for example, size, shape, and distance information. Nuclear power plants have high-radiation and underwater environments therefore the electronic parts that comprise 3D shape measurement systems are prone to degradation and thus cannot be used for a long period of time. Also, given the refraction caused by a medium change in the underwater environment, optical design constraints and calibration methods for them are required. The present study proposed a method for developing an underwater 3D shape measurement system with improved radiation tolerance, which is composed of commercial electric parts and a stereo camera while being capable of easily and readily correcting underwater refraction. In an effort to improve its radiation tolerance, the number of parts that are exposed to a radiation environment was minimized to include only necessary components, such as a line beam laser, a motor to rotate the line beam laser, and a stereo camera. Given that a signal processing circuit and control circuit of the camera is susceptible to radiation, an image sensor and lens of the camera were separated from its main body to improve radiation tolerance. The prototype developed in the present study was made of commercial electric parts, and thus it was possible to improve the overall radiation tolerance at a relatively low cost. Also, it was easy to manufacture because there are few constraints for optical design.