• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5C
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• pp.265-275
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• 2011

In this paper, we propose a Multi-Strata Space Time Code(MSSTC) for MIMO retransmissions. Since MSSTC is constructed by superimposing two OSTBC matrices, there are no intra-stratum interferences, but there exist inter-strata interferences. In MIMO retransmission environment, the transmitter switches adaptively the phases of strata at each transmission by using 1-bit feedback sent from the receiver in order to reduce the inter-strata interferences efficiently. We also propose a power allocation scheme between strata to improve error performance. Simulation results show that the proposed scheme achieves better performance than other conventional schemes.

• Earthquakes and Structures
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• v.17 no.4
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• pp.365-372
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• 2019

Post-earthquake crisis management is a key capability for a country to be able to recover after a major seismic event. Instrumental seismic data transmitted and processed in a very short time can contribute to better management of the emergency and can give insights on the earthquake's impact on a specific area. Romania is a country with a high seismic hazard, mostly due to the Vrancea intermediate-depth earthquakes. The elastic acceleration response spectrum of a seismic motion provides important information on the level of maximum acceleration the buildings were subjected to. Based on new data analysis and knowledge advancements, the acceleration elastic response spectrum for horizontal ground components recommended by the Romanian seismic codes has been evolving over the last six decades. This study aims to propose a framework for post-earthquake warning based on code spectrum exceedances. A comprehensive background analysis was undertaken using strong motion data from previous earthquakes corroborated with observational damage, to prove the method's applicability. Moreover, a case-study for two densely populated Romanian cities (Focsani and Bucharest) is presented, using data from a $5.5M_W$ earthquake (October 28, 2018) and considering the evolution of the three generations of code-based spectral levels for the two cities. Data recorded in free-field and in buildings were analyzed and has confirmed that no structural damage occurred within the two cities. For future strong seismic events, this tool can provide useful information on the effect of the earthquake on structures in the most exposed areas.

• Earthquakes and Structures
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• v.9 no.2
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• pp.391-413
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• 2015

Damage of torsionally coupled buildings situated on soil sites has been reported in literature, however no site-specific studies are available for torsionally coupled buildings having site characteristics as a parameter. Effect of torsion is being accounted in seismic codes by the provision of design eccentricity where the dynamic to static eccentricity ratio is a parameter. In this paper, a methodology to determine dynamic to static eccentricity ratio of torsionally coupled buildings has been demonstrated for Delhi region for two torsionally coupled buildings on three soil sites. The variations of average and standard deviations of frame shears for stiff and flexible edges are studied for four eccentricity ratios for the two buildings for the three sites. From the limited studies made, it is observed that the dynamic to static eccentricity ratios observed for site-specific earthquakes are different from Indian seismic code specified value, hence a proposal is made to include a comment in Indian seismic code. Methodology proposed in this paper can be adopted for any region, for the estimation of dynamic to static eccentricity ratio for site specific earthquake.

• Special Issue of the Society of Naval Architects of Korea
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• 2015.09a
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• pp.74-78
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• 2015

When floating platform or drilling unit is located at operating station during its design life, it has to have the sufficient stability considering external environment. To evaluate whether offshore structure is complied with the required design criteria for intact stability, the factors which decrease the righting moment have to be considered. Wind heeling moment is one of main factors because the direction is opposite to the righting moment. According to 2009 MODU CODE (Code for the construction and equipment of Mobile Offshore Drilling Units, 2009), wind heeling moment derived from wind tunnel test on scale model of offshore structure enables to apply as alternative given formula and method in 2009 MODU CODE. However, there is no the specific method for applying data derived from wind tunnel test. Based on the following reasons, this paper presents that the calculation method of wind heeling moment utilizing non-dimensional coefficient relative to wind loads (wind forces and moments) and the comparison with each method applying an example.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.949-952
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• 2009

In this paper, a watermarking method based on the trellis code with multi-layer is proposed. An image is divided $8{\times}8$ block with no overlapping, and compute the discrete cosine transform(DCT) of each block, and the 12 medium-frequency AC terms from each block are extracted. Next it is compared with gaussian random vectors with zero mean and unit variance. As these processing, the embedding vectors with minimum linear correlation can be obtained by Viterbi algorithm at each layer of trellis coding. To evaluate the performance of proposed method, the average bit error rate of watermark message is calculated from different several images.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.218-226
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• 2023

In Korea, we still use function point based cost estimations for software size and cost of a project. The current problem is that we make difficultly calculating function points with requirements and also have less accurate. That is, it is difficult for non-experts to analyze requirements and calculate function point values with them, and even experts often derive different function points. In addition, all stakeholders strongly make the validity and accuracy of the function point values of the project before /after the development is completed. There are methods for performing function point analysis using source code [1][2][3][4] and some researchers [5][6][7] attempt empirical verification of function points about the estimated cost. There is no research on automatic cost validation with source code after the final development is completed. In this paper, we propose automatically how to calculate Function Points based on natural language requirements before development and prove FP calculation based on the final source code after development. We expect validation by comparing the function scores calculated by forward engineering and reverse engineering methods.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.10a
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• pp.79-82
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• 1990

The results of a large-scale study to determine the effects of epoxy coating on the bond strength between deformed reinforcement and concrete are descrebed. Tests include beam-end specimens containing No. 5(16mm), No. 6 (19mm), No. 8(25mm), No. 11(32mm) bars with average coating thicknesses ranging from 3 to 17 mils(0.08-0.43mm). Three deformation patterns are evaluated. Specimens with covers of 1, 2, and 3 bar deameters are studied. Both top-cast and bottom-cast bars are tested. Epoxy coatings are found to significantly reduce bond strength. The severity of that reduction is a function of deformation pattern, bar size, and coating thickness. Design recommendations based on these observations differ from the modifications to the 1989 ACI Building Code.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.43
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• pp.201-238
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• 2009

The purpose of this paper is to describe the contents and issues of the draft legislation of Part VI the Carriage by Air of Korean Commercial Code in respect of the domestic carriage of cargo by air, comparing to the related provisions of the Montreal Convention of 1999 for the unification of certain rules for international carriage by air and the related provisions of Korean Commercial Code in respect of the carriage by land and sea. The Montreal Convention in respect of the international carriage by air was adopted in 1999, and Korea has ratified the Montreal Convention in 2007. However, there is now no national legislation in respect of the carriage by air in Korea. Thus, the Ministry of Justice has prepared the draft legislation of Part VI the Carriage by Air of the Korean Commercial Code in July 2008, and the draft legislation is now being reviewed by the National Assembly. The draft provisions of Part VI the Carriage by Air are basically adopting most of the related provisions of the Montreal Convention in respect of the carriage of cargo by air and some draft provisions are applying the related provisions of the Korean Commercial Code in respect of the carriage of cargo by land and sea. In respect of the carriage of cargo by air, the contents of the draft legislation of Part VI the Carriage by Air are composed of the provisions in respect of the liability of the carrier, the rights of the consignor and consignee, the transport document and others. In respect of the carriage of cargo by air, the issues on the draft legislation of Part VI the Carriage by Air are the problems with respect to the extinguishment of the liability of the carrier, the application for the non-contractual claim, the liability limit of the servants or agents of the carrier, the right of disposition of cargo, the effect of breach of the provision in respect of the air transport document, the prescription of claim of the carrier, the immunity reasons from liability of the carrier for the loss or damage of the cargo, the making out of the air waybill, and the effect of the statement of the air transport document. In conclusion, the national legislation of Part VI the Carriage by Air of the Korean Commercial Code will protect the right and interest of the consignor and consignee, and clarify the right and duty of the parties to the air transport. Also it will contribute to the development of the air transport industry in Korea.

• Journal of Communications and Networks
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• v.10 no.1
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• pp.5-9
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• 2008

Researchers have investigated many upper bound techniques applicable to error probabilities on the maximum likelihood (ML) decoding performance of turbo-like codes and low density parity check (LDPC) codes in recent years for a long codeword block size. This is because it is trivial for a short codeword block size. Previous research efforts, such as the simple bound technique [20] recently proposed, developed upper bounds for LDPC codes and turbo-like codes using ensemble codes or the uniformly interleaved assumption. This assumption bounds the performance averaged over all ensemble codes or all interleavers. Another previous research effort [21] obtained the upper bound of turbo-like code with a particular interleaver using a truncated union bound which requires information of the minimum Hamming distance and the number of codewords with the minimum Hamming distance. However, it gives the reliable bound only in the region of the error floor where the minimum Hamming distance is dominant, i.e., in the region of high signal-to-noise ratios. Therefore, currently an upper bound on ML decoding performance for turbo-like code with a particular interleaver and LDPC code with a particular parity check matrix cannot be calculated because of heavy complexity so that only average bounds for ensemble codes can be obtained using a uniform interleaver assumption. In this paper, we propose a new bound technique on ML decoding performance for turbo-like code with a particular interleaver and LDPC code with a particular parity check matrix using ML estimated weight distributions and we also show that the practical iterative decoding performance is approximately suboptimal in ML sense because the simulation performance of iterative decoding is worse than the proposed upper bound and no wonder, even worse than ML decoding performance. In order to show this point, we compare the simulation results with the proposed upper bound and previous bounds. The proposed bound technique is based on the simple bound with an approximate weight distribution including several exact smallest distance terms, not with the ensemble distribution or the uniform interleaver assumption. This technique also shows a tighter upper bound than any other previous bound techniques for turbo-like code with a particular interleaver and LDPC code with a particular parity check matrix.

• The KIPS Transactions:PartB
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• v.14B no.5
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• pp.321-328
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• 2007

In this paper, we propose a fast and dynamic Region-of-Interest coding method using the adaptive code-block discrimination algorithm in JPEG2000 images which complements the implicit ROI coding method and the modified implicit ROI coding method. For reducing the time of discriminating the code block, the proposed method estimates the characteristics of the shape of ROI and makes the shape of boundaries, and classifies the patterns of each code block. The method improves the preferred processing and loss of wavelet coefficients of background within the ROI code blocks by adaptively classifying the code blocks with the percentage of content of the wavelet coefficients using the thresholds of ROI and background. Also, the priority control of wavelet coefficients of background within ROI code block supports the rapid ROI coding by processing in batch based on patterns unlike the existing methods that process with unit of wavelet coefficients. To show the usefulness of this method, we compared this to the existing methods. There is no difference in performance, but we confirmed very speedy in processing time.