• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9B
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• pp.1082-1091
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• 2011

Power-reduction techniques based on DVFS(Dynamic Voltage and Frequency Scaling) are crucial for lengthening operating times of battery powered mobile systems. This paper proposes an optimal DVFS scheduling algorithm for decoders with memory size limitation on display buffer, which is realistic constraints not properly touched in the previous works. Furthermore, we mathematically prove that the proposed algorithm is optimal in the limited display buffer and limited clock frequency model, and also can be used for feasibility check. Simulation results show the proposed algorithm outperformed the previous heuristic algorithms by 7% in average, and the performance of all algorithms using display buffers saturates at about 10 frame size.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.115-118
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• 2004

Images with high resolution are desired and often required in many visual applications. When resolution can not be improved by replacing sensors, either because of cost or hardware physical limits, super resolution image reconstruction method is what can be resorted to. Super resolution image reconstruction method refers to image processing algorithms that produce high quality and high resolution images from a set of low quality and low resolution images. The method is proved to be useful in many practical cases where multiple frames of the same scene can be obtained, including satellite imaging, video surveillance, video enhancement and restoration, digital mosaicking, and medical imaging. The method can be either the frequency domain approach or the spatial domain approach. Much of the earlier works concentrated on the frequency domain formulation, but as more general degradation models were considered, later researches had been almost exclusively on spatial domain formulations. The method in spatial domains has three stages: i) motion estimate or image registration, ii) interpolation onto high resolution grid and iii) deblurring process. The super resolution grid construction in the second stage was discussed in this paper. We applied the Maximum A­Posteriori(MAP) reconstruction method that is one of the major methods in the super resolution grid construction. Based on this method, we reconstructed high resolution images from a set of low resolution images and compared the results with those from other known interpolation methods.

• Journal of The Korean Association of Information Education
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• v.11 no.2
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• pp.243-249
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• 2007

Most homepages of schools are available to publicize activities of education, to load educational materials efficiently. But we can't use current homepages of schools in making characteristic information or sharing educational resources. In this study, this I-CUBE system with RSS was designed and embodied for sharing characteristic educational activities and works in schools. Currently, I-CUBE is being under experimental test for sharing education activities and making community in elementry schools,.

• Journal of Digital Convergence
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• v.18 no.5
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• pp.425-432
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• 2020

Stereoscopic imaging is an important branch in the field of digital imaging, and has grown significantly over the last two decades through research and development. Hologram projection technology based on stereoscopic technology has been a social issue since the development of the Hungarian physicist Daniel Garber in 1947. It is becoming more and more important as stereoscopic works using similar technologies are applied to various fields. This study analyzed content cases using classical and creative stereoscopic technology from the perspective of digital image content design and explored the multiprotocol direction of holographic projection.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.186-191
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• 2008

Injection molding is used to manufacture various kinds of products including very thin plate like frames. One such product is Door video phone system Panel which is our present object of investigation. During the molding process, large deflection problems in the final product always provokes for the several trials for the accuracy. To solve the issue we use Moldflow6.2 which is injection molding simulation software. It simulates the product exactly the way it happens in actual manufacturing environment. Differences in the geometrical parameters such as thickness changes will lead to the large deformation problems in the frame. However in our present study we simulate it in a well defined condition under several trials. Interesting observations are made in minimizing the deformation of the frame during the injection molding process. This way of approach is very useful in further works if any changes have to be made in the product.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2S
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• pp.701-710
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• 2000

This paper presents a new method for an efficient coding of very low bit-rate color video based on adaptive wavelet transform. Our approach reveals that the coding process works more efficiently if the quantized wavelet coefficients are preprocessed by a mechanism exploiting the redundancies in the wavelet subband structure. Thus, we focuses optimized activity of coding part, and exhaustive overlapped block motion compensation is utilized to ensure coherency in motion compensated error frames, and raised cosine window is applied. The horizontal and vertical components of motion vectors are encoded separately using adaptive arithmetic coding while significant wavelet coefficients are encoded in bit-plane order using adaptive arithmetic coding. On average the proposed codec exceeds H.263 and ZTE in peak signal-to-noise ratio by as much as 2.07 and 1.38dB at 28 kbits, respectively. Fore entire sequence coding, 3DWCVC method is superior to H.263 and ZTE by 0.35 and 0.71dB on average, respectively.

• Journal of KIISE:Software and Applications
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• v.32 no.10
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• pp.956-962
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• 2005

To improve video quality and coding efficiency, H.264/AVC adopts different half pixel calculating method compared with the previous standards. So, the transcoder requires additional works to transcode the pre-coded video contents with the previous standards to H.264/AVC in DCT domain. In this paper, we propose the first half-pixel correction method for MPEG-2 to H.264 transcoding in DCT domain. In the proposed method, MPEG-2 block is added to the correction block obtained by difference calculation of half-pixel values between two standards using DCT reference frame. Experimental results show that the proposed achieves better quality than pixel based cascaded transcoding method.

• Journal of Broadcast Engineering
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• v.10 no.2
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• pp.202-209
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• 2005

In this paper, we propose a design of the metadata engine of the video recording system to minimize the retrieval time. For this purpose, the proposed metadata engine stores the XML metadata as a separated fragment and construct a hierarchical indexing scheme based on the contextual and structural properties of metadata. The hierarchical indexing scheme is consisted of a node index for basic searching and a group index for advanced searching. In this way our approach can minimize the number of indexes and thus the retrieval time. Our simulation results show that the response time of our proposed system is shorter than that of the previous works.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.3
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• pp.181-187
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• 2003

For the moving objects with environmental sensors such as object tracking moving robot with audio and video sensors, environmental information acquired from sensors keep changing according to movements of objects. In such case, due to lack of adaptability and system complexity, conventional control schemes show limitations on control performance, and therefore, sensory-motor systems, which can intuitively respond to various types of environmental information, are desirable. And also, to improve the system robustness, it is desirable to fuse more than two types of sensory information simultaneously. In this paper, based on Braitenberg's model, we propose a sensory-motor based fusion system, which can trace the moving objects adaptively to environmental changes. With the nature of direct connecting structure, sensory-motor based fusion system can control each motor simultaneously, and the neural networks are used to fuse information from various types of sensors. And also, even if the system receives noisy information from one sensor, the system still robustly works with information from other sensors which compensates the noisy information through sensor fusion. In order to examine the performance, sensory-motor based fusion model is applied to object-tracking four-foot robot equipped with audio and video sensors. The experimental results show that the sensory-motor based fusion system can tract moving objects robustly with simpler control mechanism than model-based control approaches.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.52-62
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• 2008

In this paper, we develop a method that changes the resolutions of images in an arbitrary block transform domain by using a filter that suits to the characteristics of the underlying images. To accomplish this, we represent each procedure resizing images in an arbitrary transform domain as matrix multiplications and we derive the matrix that scales the image resolutions from the matrix multiplications. The resolution scaling matrix is also designed to be able to select the up/down-sampling filter that suits the characteristics of the image. Experiments show that the proposed method produces the reliable performances when it is applied to various transforms and to images that are mixed with predicted and non-predicted blocks which are generated during video coding.