• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.6
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• pp.86-92
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• 2010

This paper proposes a new steganography scheme based on frequency domain using various image frames and collages that can protect the copyright of digital contents for users and securely perform to exchange the security information in the digital communication environments. The main idea of our proposed scheme is that the security informations related its copyright embed into the frequency domain of the image frame and collages when a user decorates the original image by using various image frames and collages. The strengths of our proposed scheme are as follows: (1) It allows to freely control the quantity of embedded information by changing the number of image frames and collages. (2) It is secure to variety image distortion attacks. (3) It maintains high PSNR(Peak Signal to Noise Ratio). As a result, the proposed steganography scheme can be used practically diverse multimedia security fields such as digital copyright protect, secure message communication and digital watermarking.

• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1149-1158
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• 2003

Content adaptive watermark embedding algorithm using a stochastic image model in the multiwavelet transform is proposed in this paper. A watermark is embedded into the perceptually significant coefficients (PSCs) of each subband using multiwavelet transform. The PSCs in high frequency subband are selected by SSQ, that is, by setting the thresholds as the one half of the largest coefficient in each subband. The perceptual model is applied with a stochastic approach based on noise visibility function (NVF) that has local image properties for watermark embedding. This model uses stationary Generalized Gaussian model characteristic because watermark has noise properties. The watermark estimation use shape parameter and variance of subband region. it is derive content adaptive criteria according to edge and texture, and flat region. The experiment results of the proposed watermark embedding method based on multiwavelet transform techniques were found to be excellent invisibility and robustness.

• Journal of Korea Multimedia Society
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• v.10 no.1
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• pp.74-82
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• 2007

IPv6 is the internet protocol for next generation which can solve the problem of IPv4 protocol. Mobile IPv6 efficiently provides the mobility for mobile devices holding the properties of IPv6. iSCSI(Internet Small Computer System Interface) is a block-oriented storage access protocol that enables a user to recognize a remote storage as their own local block device through general TCP/IP networks. Since iSCSI uses a standard Ethernet switch and router for this kind of access, it can not only be applized to Ethernet technologies, but can also be used to create a storage networking system without any distance restrictions that can equally be applied to a wireless network environment. Accordingly, this paper presents an alternative approach to overcome the limited storage space of mobile devices based on the IPv6 iSCSI initiator driver which was originally designed for wired networks. Also, this paper describes about the implementation and performance analysis of mobile education service system using virtual storage devices in IPv6 wireless networks.

• Journal of Information Processing Systems
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• v.2 no.2
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• pp.76-81
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• 2006

A PDA is used mainly for downloading data from a stationary server such as a desktop PC in an infrastructure network based on wireless LAN. Thus, the overall performance depends heavily on the performance of such downloading with PDA. Unfortunately, for a PDA the time taken to receive data from a PC is longer than the time taken to send it by 53%. Thus, we measured and analyzed all possible factors that could cause the receiving time of a PDA to be delayed with a test bed system. There are crucial factors: the TCP window size, file access time of a PDA, and the inter-packet delay that affects the receiving time of a PDA. The window size of a PDA during the downstream is reduced dramatically to 686 bytes from 32,581 bytes. In addition, because flash memory is embedded into a PDA, writing data into the flash memory takes twice as long as reading the data from it. To alleviate these, we propose three distinct remedies: First, in order to keep the window size at a sender constant, both the size of a socket send buffer for a desktop PC and the size of a socket receive buffer for a PDA should be increased. Second, to shorten its internal file access time, the size of an application buffer implemented in an application should be doubled. Finally, the inter-packet delay of a PDA and a desktop PC at the application layer should be adjusted asymmetrically to lower the traffic bottleneck between these heterogeneous terminals.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.8
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• pp.315-320
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• 2015

The purposed of this research is to develop multimedia content usage analysis service platform. In the proposed platform, the content gazing behaviors of the users are monitored and profiled in real-time and a set of quantifiable metrics is provided. These metrics are used to determine the closeness of the users' behavior from the intent set by the provider. Based on the evaluation, it is possible to assess the effectiveness of the contents themselves as well. The content usage assessment is accomplished by utilizing the intention flow and the intent weight, which are embedded into the content by the content provider. Proposed methodology can be effectively applied and used in various application domains such as in education and in commercial advertisements.

• Journal of Korea Multimedia Society
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• v.9 no.4
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• pp.515-527
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• 2006

Domestic standards for data broadcasting differ in the fact that satellite broadcasting chose MHP, cable OCAP, satellite ACAP, therefore making reuse of data contents impossible due to the differences. To resolve this problem, this study designed and implemented independent middleware class library for developing data broadcasting contents. To define class library which could bridge between applications and different middleware, standard library developing methods were used; and analysis of procedural application of each middleware was carried out. Based upon the analysis, classes with embedded transform and handle modules were defined to be linked to libraries of each middleware; and to verify the implemented class library, test contents were created to be compared to the existing contents. This kind of contents development by independent middleware class library allows for reuse of data contents easier, and develops an environment for higher quality of contents by reducing the efforts needed to learn each middleware for the developers.

• Journal of Korea Multimedia Society
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• v.6 no.3
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• pp.508-517
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• 2003

This paper presents perceptual model with a stochastic multiresolution characteristic that can be applied with watermark embedding in the biorthogonal wavelet domain. The perceptual model with adaptive watermarking algorithm embeds at the texture and edge region for more strongly embedded watermark by the SSQ. The watermark embedding is based on the computation of a NVF that has local image properties. This method uses non- stationary Gaussian and stationary Generalized Gaussian models because watermark has noise properties. The particularities of embedding in the stationary GG model use shape parameter and variance of each subband regions in multiresolution. To estimate the shape parameter, we use a moment matching method. Non-stationary Gaussian model uses the local mean and variance of each subband. The experiment results of simulation were found to be excellent invisibility and robustness. Experiments of such distortion are executed by Stirmark 3.1 benchmark test.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.703-709
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• 2008

The methodology of the compiler construction improved by well-defined parsing techniques and developments of automatic generation tools. Through them, a variety of compilers for the special applications can be developed effectively: particularly, the compiler for embedded/mobile devices. Also, as contents industry is proliferating recently, the necessity of developing a compiler which is suitable for contents system is highly increasing. These various demands can be resolved by modular techniques and automatic construction of compilers. But, optimization of compiler itself as development tools uses heuristic methods and it needs higher cost. In this paper, we suggest the parsing method which can decrease unnecessary reduce actions by analyzing the characteristics of LR parser. The suggested parsing technique uses lookahead/ states, reachable reduction goals information in parsing process and enhances the parsing efficiency by changing continuous reduce actions to one. Actually, we applied it to the front-end of ANSI C compiler and proved the parsing performance in terms of the number of reduce actions.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.651-660
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• 2008

Flash memory is widely used in embedded systems because of its benefits such as non-volatile, shock resistant, and low power consumption. However, NAND flash memory suffers from out-place-update, limited erase cycles, and page based read/write operations. To solve these problems, YAFFS and RFFS, the flash memory file systems, are proposed. However YAFFS takes long time to mount the file system, because all the files are scattered all around flash memory. Thus YAFFS needs to fully scan the flash memory. To provide fast mounting, RFFS has been proposed. It stores all the block information, the addresses of block information and meta data to use them at mounting time. However additional operations for the meta data management are decreasing the performance of the system. This paper presents a new NAND flash file system called ERFFS (Efficient and Reliable Flash File System) which provides fast mounting and recovery with minimum mata data management. Based on the experimental results, ERFFS reduces the flash mount/recovery time and the file system overhead.

• Journal of Korea Multimedia Society
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• v.8 no.11
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• pp.1462-1471
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• 2005

Recently, the medical image has been digitized by the development of computer science and digitization of the medical devices. There are needs for database service of the medical image and long term storage because of the construction of PACS(picture archiving and communication system) following DICOM(digital imaging communications in medicine) standards, telemedicine, and et al. However, it also caused some kinds of problems, such as illegal reproduction of medical image, proprietary rights and data authentication. In this paper, we propose the new digital watermarking technique for medical image based on public key encryption algorithm for integrity verification. It prevents illegal forgery that can be caused after transmitting medical image data remotely. The watermark is the value of bit-plane in wavelet transform of the original image for certification method of integrity verification. We proposed the embedding regions are randomly chosen considering ROI, and a digital signature is made using hash function of MD5 which input is a secret key. The experimental results show that the watermark embedded by the proposed algorithm can survive successfully in image processing operations and that the watermark's invisibility is good.