• Journal of Life Science
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• v.16 no.2 s.75
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• pp.213-218
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• 2006

The study of genetic diversity and population structure was carried out in the Codium fragile using allozyme analysis. Although this species has been regarded as a ecologically and economically important source, there is no report on population structure in Korea. Starch gel electrophoresis was used to investigate the allozyme variation and genetic structure of four Korean populations of this species. Of the 15 genetic loci surveyed, nine (60.0%) was polymorphic in at least one population. Genetic diversity was high at the species level ($H_{ES}$=0.144), and, that of the population level was relatively low ($H_{EP}$=0.128). Nearly 87% of the total genetic diversity in C. fragile was apportioned within populations. The predominant asexual reproduction, population fragmentation, low fecundity, geographic isolation and colonization process are proposed as possible factors contributing to low genetic diversity in this species. The indirect estimated of gene flow based on $G_{ST}$ was 1.69. The moderate level of gene flow in C. fragile populations is mainly caused by thallus developed from isolated utricles dispersal via sea current.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.89-98
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• 2015

This paper provides a robust and non-fragile $H_{\infty}$ controller design algorithm for time-delayed systems with randomly occurring polytopic uncertainties and disturbances. First, we design time-delayed system considering randomly occurring uncertainties and disturbances. Next, The sufficient condition for the existence of robust and non-fragile $H_{\infty}$ controller is presented by LMI(linear matrix inequality) using Lyapunov stability analysis and $H_{\infty}$ performance measure. Since the obtained condition can be expressed as a PLMI(parameterized linear matrix inequality) by changes of variables and Schur complement, all solutions including controller gain, degrees of controller satisfying non-fragility, $H_{\infty}$ norm bound ${\gamma}$ can be calculated simultaneously. Finally, numerical examples are given to illustrate the performance and the effectiveness of the proposed robust and non-fragile $H_{\infty}$ controller compared with the deterministic uncertainty model even though there exists randomly occurring uncertainties, disturbances and time delays.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.223-229
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• 2021

To evaluate the protective effect of Codium fragile on fine dust (PM2.5)-induced cytotoxicity, we investigated its antioxidant activity and cell protective effect on PM2.5-exposed cells. The 40% ethanolic extract of C. fragile showed the highest total phenolic content, whereas the water extract of C. fragile showed the highest total polysaccharide content. The protective effect of the extracts on PM2.5-induced oxidative damage in nasal cavity (RPMI2650), lung (A549), brain (MC-IXC), hippocampus (HT-22), and microglia (BV-2) cells was evaluated by measuring the intracellular reactive oxygen species (ROS) content and cell viability. The results showed that the 40% ethanolic extract more efficiently inhibited ROS production than the water extract. In contrast, PM2.5-exposed cells treated with the water extract showed higher viability than those treated with the 40% ethanolic extract.

• East Asian Economic Review
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• v.21 no.2
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• pp.167-197
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• 2017

I build a small open economy (SOE) dynamic stochastic general equilibrium (DSGE) model to investigate the effect of a heterogeneous wage contract between regular and temporary workers on a macroeconomic volatility in a financially fragile economy. The imperfect financial market condition is captured by a quadratic financial adjustment cost for borrowing foreign assets, and the labor market friction is captured by a Nash bargaining process which is only available to the regular workers when they negotiate their wages with the firms while the temporary workers are given their wage which simply equals the marginal cost. As a result of impulse responsesto a domestic productivity shock, the higher elasticity of substitution between two types of workers and the lower weight on the regular workers in the firm's production process induce the higher volatilities in most variables. This is reasoned that the higher substitutability creates more volatile wage determination process while the lower share of the regular workers weakens their Nash bargaining power in the contract process.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3269-3277
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• 1999

To promote the inclusion of end-to-end congestion control in the design of future protocols using best-effort traffic, we propose a router mechanism, Extended FRED(ex-FRED). In this paper, we catagorize the TCP controlled traffics into robust and fragile traffic and discuss several unfairness conditions between them caused by the diverse applications. For example, fragile traffic from bursty application cannot use its fair share due to their slow adaptation. Ex-FRED modifies the FRED(Fair Random Early Drop), which can show wrong information due to the narrow view of actual buffer. Therefore, Ex-FRED uses per-flow accounting in larger virtual buffer to impose an each flow a loss rate that depends on the virtual buffer use of a flow. The simulation results show that Ex-FRED uses fair share and has good throughput.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.875-878
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• 2001

본 논문에서는 디지털 영상의 변조를 확인함과 동시에 변조의 위치를 확인하는 연성 워터마킹(fragile watermarking)을 위하여 DCT를 통해 블록의 에너지를 계산한 후, 에너지의 단계별로 워터마크의 삽입량을 조절하는 방법을 제안한다. 디지털 영상의 소유권 확인을 위해 디지털 서명을 사용하며, 영상에 DCT를 수행함으로서 모든 픽셀에 워터마크를 삽입하지 않고서도 변조의 유무를 확인하는 것이 가능하 방식이다. DCT 계수로 각 블록의 에너지를 계산하여 블록의 관계를 분류하며 에너지가 작은 블록들과 큰 블록들은 이간의 시각에 민감한 부분이므로 워터마크의 삽입 양을 줄이고, 중간 단계의 블록일수록 워터마크의 삽입 양을 늘린다. 에너지의 단계 분류에 의해 가변적으로 워터마크를 삽입함으로 워터마크의 비가시성과 연성을 만족시키며 변조의 유무와 위치를 확인할 수 있게 된다.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2149-2154
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• 2015

This paper proposes a novel watermarking method to discover the tampers and localize it in digital image. The image which is to be used to generate a watermark is first wavelet decomposed and the edge feature from the sub bands of high frequency coefficients are retrieved to generate a watermark (Edge Feature Image) and which is to be embed on the cover image. Before embedding the watermark, the pixels of cover image are disordered through the Arnold Transform and this helps to upgrade the security of the watermark. The embedding of generated edge feature image is done only on the Least Significant Bit (LSB) of the cover image. The invisibleness and robustness of the proposed method is computed using Peak-Signal to Noise Ratio (PSNR) and Normalized Correlation (NC) and it proves that the proposed method delivers good results and the proposed method also detects and localizes the tampers efficiently. The invisibleness of proposed method is compared with the existing method and it proves that the proposed method is better.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.216-221
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• 2006

This study provides a methodology for development of the Seismic Damage Evaluation System (SDES) in Korea. Major systems and status of database related to road networks in Korea are investigated to analyze the usability of the required information for developing the SDES. In this study, the SDES is composed of four components that are the road network component, the ground motion component, the fragile structure component, and the cost component. In addition, the procedures for the construction of database which support the SDES is proposed, and a prototype of the SDES for expressway of Korea is developed based on the developed methodology. The National Geospatial Information System (NGIS) and the National Earthquake Information System (NEIS) are used to develop the road network component and ground motion component, respectively. For the fragile structure component and the cost component, Highway Bridge Management System (HEMS) was used.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.272-272
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• 2000

since the controller is part or the overall closed-Loop system, it is necessary that the designed controller be able to tolerate some uncertainty in its coefficients. The adequate stability and performance margins are required for the designed nominal controllers. In the paper. we study the method to design the non-fragile fixed-structured controller for real parametric uncertain systems. When we impose the controller parameter perturbation, the structure of the controller must be given. Therefore, we assume that the controller has fixed-structure. The fixed-structure controller is practically necessary especially when the robust controller synthesis results in a high-order controller. In SISO systems, we propose the robust controller design method using the Mapping theorem. In the method, the plant uncertainty and controller Parameter are of the multilineal form in the stability and performance conditions. Then, the controller synthesis problem is easily recast to Linear Programming Problem.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.458-471
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• 2006

Digital watermarking of multimedia data is a very active research area that has enjoyed a considerable amount of attention in recent years. In this paper, we propose an algorithm for embedding/detecting a fragile watermark in MPEG-4 compressed video domain (Simple and Advance Simple Profiles). The watermark bits are put directly into Huffman VLC-codespace of quantized DCT domain. The advantage of watermark embedding into the compressed domain is the significant savings for a real-time implementation as it does not require a full decoding operation. The watermark embedding does not change the video file size. The algorithm demonstrates high watermarking capacity, thereby providing reliable foolproof authentication. The results of experimental testing demonstrate that watermark embedding preserves the video quality. Watermark detection is performed without using the original video.