• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.12
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• pp.1043-1053
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• 2012

In distributed video coding (DVC) systems, the complexity of encoders is greatly reduced by removing the motion estimation operations in encoders, since the correlation between frames is utilized in decoders. The transmission of parity bits is requested through the feedback channel, until the related errors are corrected to decode the Wyner-Ziv frames. The requirement to use the feedback channel limits the application of DVC systems. In this paper, we propose an efficient method to remove the feedback channel in DVC systems. First, a simple side information generation method is proposed to calculate the amount of parity bits in the encoder, and it is shown that the proposed method yields good performance with low complexity. Then, by calibrating the theoretical entropy with three parameters, we can calculate the amount of parity bits in the encoder and remove the feedback channel. Moreover, an adaptive method to determine quantization parameters for key frames is proposed. Extensive computer simulations show that the proposed method yields better performance than conventional methods.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.6 s.40
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• pp.13-22
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• 2004

Ductiluty factor has played an important role in seismic design as it is key component of response modification factor(R). In this stuty, ductility factors() are calculated by multiplying ductility factor for SDOF systems() and MDOF modification factors(). Ductility factors() for SDOF systems are computed from nonlinear dynamic analysis undergoing different level of displacement ductiluty demands and period when subjected to a large number of recorded earthquake ground motions. The MDOF modification factors() are proposed to account for the MDOF systems, based on previous studies. A total of 108 prototype steel frames are designed to investigate the ductility factors considering the number of stories(4, 8 and 16-stories), framing system(Perimeter Frames, PF and Distributed Frames, DF), failure mechanism(Strong-Column Weak-Beam, SCWB and Weak-Column Strong-Beam, WCSB), soil profiles(SA, SC and SE in UBC 1997) and seismic zone factors(Z=0.075, 0.2 and 0.4 in UBC 1997). It is shown that the number of stories, failure mechanisms (SCWB, WCSB), and soil profiles have great influence on the ductility factors, however, the structural system(Perimeter frames, Distributed frames), and seismic zones have no influence on the ductility factors.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.539-541
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• 2005

We propose efficient video retrieval scheme which use fast key frame extraction in DCT domain. Our scheme extract key frame using the edge histogram difference which is extracted in compressed domain for I-frames. And the video retrieval is implemented using Hausdorff distance function about edge histogram of key frame. This approach enables fast content-based video retrieval of the compressed video content without decompression process. Experimental results show our scheme is very fast and efficient.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.536-538
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• 2005

As multimedia data and huge-Quantity video data having been increasingly and commonly used, the key frame algorithm, as one of the methods for manipulating these kinds of data, became an important matter and has been studied for many years. But the formerly proposed key frame extraction methods take much processing time or need complex calculations due to decoding processes. In order to solve these problems which the former methods have and to enhance the key frame extraction efficiency, a novel key frame extraction method in compressed domain is proposed in this paper. In this method we get an edge histogram for each I-frame in DCT domain and then extract the key frames by means of histogram difference metric. Experimental results show that our algorithm achieves fast processing speed and high accuracy.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.787-798
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• 2004

High performance net재rking is one of key factors to provide support for data intensive applications in the Internet. Extended frame size has a major impact on end to-end performance with increasing effective TCP throughput and decreasing system overhead. Most of the research about extended frames has focused on local area network performance and the impact that extended frame size has on the system elements including memory, network interface card and so forth. In the paper, we analyse the effects of the extended frames to the other traffic flows sharing Internet paths for the wide area performance of TCP by conducting various network simulations. Results show that securing available bandwidth in no loss and low delay networks is indispensable to exploit the efficiency of extended frames.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.7
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• pp.95-102
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• 1998

This paper proposes a synchronization method of synthetic facial iamge sequences and synthetic speech. The LP-PSOLA synthesizes the speech for each demi-syllable. We provide the 3,040 demi-syllables for unlimited synthesis of the Korean speech. For synthesis of the Facial image sequences, the paper defines the total 11 fundermental patterns for the lip shapes of the Korean consonants and vowels. The fundermental lip shapes allow us to pronounce all Korean sentences. Image synthesis method assigns the fundermental lip shapes to the key frames according to the initial, the middle and the final sound of each syllable in korean input text. The method interpolates the naturally changing lip shapes in inbetween frames. The number of the inbetween frames is estimated from the duration time of each syllable of the synthetic speech. The estimation accomplishes synchronization of the facial image sequences and speech. In speech synthesis, disk memory is required to store 3,040 demi-syllable. In synthesis of the facial image sequences, however, the disk memory is required to store only one image, because all frames are synthesized from the neutral face. Above method realizes synchronization of system which can real the Korean sentences with the synthetic speech and the synthetic facial iage sequences.

• Steel and Composite Structures
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• v.3 no.3
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• pp.185-198
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• 2003

The concept of performance based seismic design has been gradually accepted by the earthquake engineering profession recently, in which the cost-effectiveness criterion is one of the most important principles and more attention is paid to the structural performance at the inelastic stage. Since there are many uncertainties in seismic design, reliability analysis is a major task in performance based seismic design. However, structural reliability analysis may be very costly and time consuming because the limit state function is usually a highly nonlinear implicit function with respect to the basic design variables, especially for the complex large-scale structures for dynamic and nonlinear analysis. Understanding statistical properties of the structural inelastic deformation, which is the aim of the present paper, is helpful to develop an efficient approximate approach of reliability analysis. The present paper studies the statistical properties of the maximum elastoplastic story drift of steel frames subjected to earthquake load. The randomness of earthquake load, dead load, live load, steel elastic modulus, yield strength and structural member dimensions are considered. Possible probability distributions for the maximum story are evaluated using K-S test. The results show that the choice of the probability distribution for the maximum elastoplastic story drift of steel frames is related to the mean value of the maximum elastoplastic story drift. When the mean drift is small (less than 0.3%), an extreme value type I distribution is the best choice. However, for large drifts (more than 0.35%), an extreme value type II distribution is best.

• Journal of Korea Multimedia Society
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• v.20 no.5
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• pp.731-739
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• 2017

Distributed compressed video sensing (DCVS) is a framework that integrates both compressed sensing and distributed video coding characteristics to achieve a low complexity video sampling. In DCVS schemes, motion estimation & motion compensation is employed at the decoder side, similarly to distributed video coding (DVC), for a low-complex encoder. However, since a simple BCS-SPL algorithm is applied to a residual arising from motion estimation and compensation in conventional MC-BCS-SPL (motion compensated block compressed sensing with smoothed projected Landweber) scheme, the reconstructed visual qualities are severly degraded in Wyner-Ziv (WZ) frames. Furthermore, the scheme takes lots of iteration to reconstruct WZ frames. In this paper, the conventional MC-BCS-SPL algorithm is improved to be operated in more effective way in WZ frames. That is, first, the proposed algorithm calculates a correlation coefficient between two reference key frames and, then, by selecting adaptively the reference frame, the residual reconstruction in pixel domain is performed to the conventional BCS-SPL scheme. Experimental results show that the proposed algorithm achieves significantly better visual qualities than conventional MC-BCS-SPL algorithm, while resulting in the significant reduction of the decoding time.

• The KIPS Transactions:PartB
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• v.11B no.6
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• pp.701-708
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• 2004

Existing contents-based video retrieval systems search by using a single method such as annotation-based or feature-based retrieval. Hence, it not only shows low search efficiency, but also requires many efforts to provide system administrator or annotator with a perfect automatic processing. Tn this paper, we propose an agent-based, and automatic and unified semantics-based video retrieval system, which support various semantics-retrieval of the massive video data by integrating the feature-based retrieval and the annotation-based retrieval. The indexing agent embodies the semantics about annotation of extracted key frames by analyzing a fundamental query of a user and by selecting a key-frame image that is ed by a query. Also, a key frame selected by user takes a query image of the feature-based retrieval and the indexing agent searches and displays the most similar key-frame images after comparing query images with key frames in the database by using the color-multiple-partition histogram techniques. Furthermore, it is shown that the performance of the proposed system can be significantly improved.

• Earthquakes and Structures
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• v.18 no.5
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• pp.527-542
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• 2020

In traditional eccentrically braced steel frames, damages and plastic deformations are limited to the links and the main structure members are required tremendous sizes to ensure elasticity with no damage based on the force-based seismic design method, this limits the practical application of the structure. The high strength steel frames with eccentric braces refer to Q345 (the nominal yield strength is 345 MPa) steel used for links, and Q460 steel utilized for columns and beams in the eccentrically brace steel frames, the application of high strength steels not only brings out better economy and higher strength, but also wider application prospects in seismic fortification zone. Here, the structures with four type eccentric braces are chosen, including K-type, Y-type, D-type and V-type. These four types EBFs have various performances, such as stiffness, bearing capacity, ductility and failure mode. To evaluate the seismic behavior of the high strength steel frames with variable eccentric braces within the similar performance objectives, four types EBFs with 4-storey, 8-storey, 12-storey and 16-storey were designed by performance-based seismic design method. The nonlinear static behavior by pushover analysis and dynamic performance by time history analysis in the SAP2000 software was applied. A total of 11 ground motion records are adopted in the time history analysis. Ground motions representing three seismic hazards: first, elastic behavior in low earthquake hazard level for immediate occupancy, second, inelastic behavior of links in moderate earthquake hazard level for rapid repair, and third, inelastic behavior of the whole structure in very high earthquake hazard level for collapse prevention. The analyses results indicated that all structures have similar failure mode and seismic performance.