• Ocean Systems Engineering
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• v.13 no.4
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• pp.349-365
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• 2023

Targeting a floating wave and offshore wind hybrid power generation system (FWWHybrid) designed in the Republic of Korea, this study examines the impact of the interaction, with multiple wave energy converters (WECs) placed on the platform, on platform motion. To investigate how the motion of WECs affects the behavior of the FWWHybrid platform, it was numerically compared with a scenario involving a 'single-body' system, where multiple WECs are constrained to the platform. In the case of FWWHybrid, because the platform and multiple WECs move in response to waves simultaneously as a 'multi-body' system, hydrodynamic interactions between these entities come into play. Additionally, the power take-off (PTO) mechanism between the platform and individual WECs is introduced for power production. First, the hydrostatic/dynamic coefficients required for numerical analysis were calculated in the frequency domain and then used in the time domain analysis. These simulations are performed using the extended HARP/CHARM3D code developed from previous studies. By conducting regular wave simulations, the response amplitude operator (RAO) for the platform of both single-body and multi-body scenarios was derived and subsequently compared. Next, to ascertain the difference in response in the real sea environment, this study also includes an analysis of irregular waves. As the floating body maintains its position through connection to a catenary mooring line, the impact of the slowly varying wave drift load cannot be disregarded. To assess the influence of the 2^nd-order wave exciting load, irregular wave simulations were conducted, dividing them into cases where it was not considered and cases where it was included. The analysis of multi-degree-of-freedom behavior confirmed that the action of multiple WECs had a substantial impact on the platform's response.

• Journal of the Korea Society of Computer and Information
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• v.17 no.7
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• pp.1-11
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• 2012

As process technology scales down, the number of cores integrated into a processor increases dramatically, leading to significant performance improvement. Especially, the GPU(Graphics Processing Unit) containing many cores can provide high computational performance by maximizing the parallelism. In the GPU architecture, the access latency to the main memory becomes one of the major reasons restricting the performance improvement. In this work, we analyze the performance improvement of the 3D GPU architecture compared to the 2D GPU architecture quantitatively and investigate the potential problems of the 3D GPU architecture. In general, memory instructions account for 30% of total instructions, and global/local memory instructions constitutes 60% of total memory instructions. Therefore, the performance of the 3D GPU is expected to be improved significantly compared to the 2D GPU by reducing the delay of memory instructions. However, according to our experimental results, the 3D architecture improves the GPU performance only by 2% compared to the 2D architecture due to the memory bottleneck, since the performance reduction due to memory bottleneck in the 3D GPU architecture increases by 245% compared to the 2D architecture. This paper provides the guideline for suitable memory design by analyzing the efficiency of the memory architecture in 3D GPU architecture.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.3
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• pp.127-143
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• 2022

Recently, many attempts to run numerical ocean models in cloud computing environments have been tried actively. A cloud computing environment can be an effective means to implement numerical ocean models requiring a large-scale resource or quickly preparing modeling environment for global or large-scale grids. Many commercial and private cloud computing systems provide technologies such as virtualization, high-performance CPUs and instances, ether-net based high-performance-networking, and remote direct memory access for High Performance Computing (HPC). These new features facilitate ocean modeling experimentation on commercial cloud computing systems. Many scientists and engineers expect cloud computing to become mainstream in the near future. Analysis of the performance and features of commercial cloud services for numerical modeling is essential in order to select appropriate systems as this can help to minimize execution time and the amount of resources utilized. The effect of cache memory is large in the processing structure of the ocean numerical model, which processes input/output of data in a multidimensional array structure, and the speed of the network is important due to the communication characteristics through which a large amount of data moves. In this study, the performance of the Regional Ocean Modeling System (ROMS), the High Performance Linpack (HPL) benchmarking software package, and STREAM, the memory benchmark were evaluated and compared on commercial cloud systems to provide information for the transition of other ocean models into cloud computing. Through analysis of actual performance data and configuration settings obtained from virtualization-based commercial clouds, we evaluated the efficiency of the computer resources for the various model grid sizes in the virtualization-based cloud systems. We found that cache hierarchy and capacity are crucial in the performance of ROMS using huge memory. The memory latency time is also important in the performance. Increasing the number of cores to reduce the running time for numerical modeling is more effective with large grid sizes than with small grid sizes. Our analysis results will be helpful as a reference for constructing the best computing system in the cloud to minimize time and cost for numerical ocean modeling.

• Structural Engineering and Mechanics
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• v.50 no.6
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• pp.755-772
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• 2014

A simplistic approach towards evaluation of complete load deflection response of Reinforced Concrete (RC) flexural members under post fire (residual) scenario is presented in this paper. The cross-section of the RC flexural member is divided into a number of sectors. Thermal analysis is performed to determine the temperature distribution across the section, for given fire duration. Temperature-dependent stress-strain curves for concrete and steel are then utilized to perform a moment-curvature analysis. The moment-curvature relationships are obtained for beams exposed to different fire durations. These are then utilized to obtain the load-deflection plots following pushover analysis. Moreover one of the important issues of modeling the initial stiffness giving due consideration to stiffness degradation due to material degradation and thermal cracking has also been addressed in a rational manner. The approach is straightforward and can be easily programmed in spreadsheets. The presented approach has been validated against the experiments, available in literature, on RC beam subjected to different fire durations viz. 1hr, 1.5hrs and 2hrs. Complete load-deflection curves have been obtained and compared with experimentally reported counterparts. The results also show a good match with the results obtained using more complicated approaches such as those involving Finite element (FE) modeling and conducting a transient thermal stress analysis. Further evaluation of the beams during fire (at elevated temperatures) was performed and a comparison of the mechanical behavior of RC beams under post fire and during fire scenarios is made. Detailed formulations, assumptions and step by step approach are reported in the paper. Due to the simplicity and ease of implementation, this approach can be used for evaluation of global performance of fire affected structures.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.7
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• pp.1007-1018
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• 2004

Luxury fashion brand business is one of the most successful global businesses in these days. The luxury fashion brands with strong brand power permeates through various regions of the world with high added value and buying power. This study was conducted to determine the dimensions of the luxury fashion brand equity so that the fashion marketers can develop strategies to increase their brand power. ID find out the dimensions of the luxury fashion brand equity, qualitative as well as quantitative research methods were employed. Qualitative research was conducted by interviewing 12 consumers who were loyal to the luxury fashion brands. A total of ten dimensions(uniqueness, sophistication, display, economical and utility value, overall pleasure, satisfaction, reputation, trust respect, social acceptance) were identified as a result of the literature review and the qualitative analysis, and a questionnaire was developed based on them. The questionnaire was administered to 250 subjects and the responses were analyzed by factor analysis to confirm the dimensions empirically. As a result of factor analysis, 7 dimensions of fashion luxury brand equity are ＇chic and pleasure＇, ＇trust＇, ＇distinction＇, ＇reputation＇, ＇economical and utility value＇, ＇social acceptance＇, and ＇status＇. First, ＇reputation＇, ＇economical and utility value＇ and ＇social acceptance＇ are similar to the result of the literature review and the qualitative analysis. Next, ＇Chic and pleasure＇ included ＇overall pleasure＇,＇display＇and＇sophistication＇that were identified previously. We knew that People would expect emotional responses such as display through luxury fashion brand. ＇Trust＇ included ＇trust＇ and ＇satisfaction＇ that were identifed previously. ＇Distinction＇ included ＇uniqueness＇ and ＇respect＇ that were identifed previously. Finally, ＇status＇ included ＇sophistication＇ and ＇reputation＇ It seemed that the concept of ＇sophistication＇ was near symbolic rather than descriptive.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.121-131
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• 2016

This research aims to analyze domestic articles related to entrepreneurship and elicit implications for future research. To this end, bibliometric analysis was conducted for the authors and titles of 1,887 articles published in the Korean Citation Index between 1997 and 2016. First, in the author analysis, Dae Yong Chung, Bong Sik Bin & Jeong Ki Park, and Sung Sik Bahn were noticeable in terms of the number of articles, the number of citation and the formation of the researchers' network. Second, in the title analysis, the characteristics of entrepreneurs and education in entrepreneurship, entrepreneurial strategies and case studies, the empirical analyses regarding entrepreneurial performance, investment in startups, and Korean IT companies were found to be the most active research fields. The results of this study can be used in selecting co-researchers and exploring research areas in the future.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.235-242
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• 2010

In recent years, the busan port is now facing a serious crisis. Exterally, though worldwide economics depression is a serious factor, cuttthroat competition between north port and new port since new port open lead to decrease terminal profitability and busan port image. The essential cause is crowed with terminal operators. therefore, This paper empirically analyze the container terminal integration factor solving busan port problem affecting the competitiveness performance. According to research results, integration between operators will be to acomplish global terminal, and so, contribute to increase service power, port productivity, cargoes and to be hub-port at the north-east asia. These results show political suggestions for importance of repid integration to improve busan port's competitiveness.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.3069-3085
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• 2018

In this study, we examined the effect of non-cognitive factors on job tenure and tenure using KLIPS. We examine the internal consistency of the big5 personality trait and of the locus of control, and use the parameterized proportional hazards model. As a result, we confirmed that non-cognitive skill such as personality traits and locus of control affect individual labor market performance. Conscientiousness has shown that the job seeking period of adult job seekers is lengthened, thereby lowering the unemployment rate. It can be understood that high attentiveness under uncertainty can misinterpret information, and that lack of decision restricts escape from unemployment. In the tenure analysis, people with internal locus of control tendency were less likely to leave the job due to longer tenure. Those who have internal control can not only be preferred by the organization but also the internal control tendency seems to be the factor that maintains the long-term job because of the motivation and self-control of their actions.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.421-431
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• 2023

Recently, the destructive power of typhoons is continuously increasing due to the influence of global warming. In a situation where the installation of floating wind turbines is increasing around the world, concerns about the huge loss and collapse of floating offshore wind turbines due to strong typhoons are deepening. Regarding to the safe operation of the floating offshore wind turbine, the development of a new type of disconnectable mooring system is required. A new fairlead chain stopper considered in this study is devised to more easily attach or detach the floating offshore wind turbine with mooring lines comparing to other disconnectable mooring apparatuses. In order to investigate the structural safety of the initial design of fairlead chain stopper that can be applied to MW-class floating type offshore wind turbine, scale-down structural models were produced using a 3-D printer and structural tests were performed on the models. For the structural tests of the scale-down models, tensile specimens of acrylonitrile butadiene styrene material that was used in the 3-D printing were prepared, and the material properties were evaluated by performing the tensile tests. The finite element analysis of fairlead chain stopper was performed by applying the material properties obtained from the tensile tests and the same load and boundary conditions as in the scale-down model structural tests. Through the finite element analysis, the structural weak parts on the fairlead chain stopper were reviewed. The structural model tests were performed considering the main load conditions of fairlead chain stopper, and the test results were compared to the finite element analysis. Through the results of this study, it was possible to experimentally verify the structural safety of the initial design of fairlead chain stopper. It is also judged that the study results can be usefully used to improve the structural strength of fairlead chain stopper in a detailed design stage.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.41-41
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• 2023

Red pepper (Capsicum annuum L.) is one of the most consumed vegetable worldwide. In this study, we tried to suggest the possibility of Cheongyang pepper as a functional cosmetic material by identifying the physiological activity, especially antioxidant and whitening effects of Cheongyang pepper through bibliometric analysis and experimental studies. A bibliometric analysis was performed through co-word analysis of 8,892 papers retrieved from SCOPUS. 4 research fields were obtained by cluster mapping from VOSviewer software, among which we noted the antioxidant activity of extracts from Capsicum annum L.. Phenol as a useful ingredient of Cheongyang pepper was analyzed using HPLC (high-performance liquid chromatography). Antioxidant and whitening effects were evaluated by measuring DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, hydrogen peroxide scavenging activity, and tyrosinase inhibitory activity. Cheongyang pepper extract showed contents of 0.106 ± 0.01 and 0.105 ± 0.02 mg/g, respectively, in the order of gallic acid and protocatechuic acid. The extract exhibited 56.95% DPPH scavenging activity and 43.97% hydrogen peroxide scavenging activity at a concentration of 1,000 ㎍/ml. In addition, 1,000 ㎍/ml of the extract inhibited tyrosinase activity by 52.44% and 42.61%, respectively in a whitening efficacy test using L-tyrosine and L-DOPA (L-3,4- dihydroxyphenylalanine) as substrates. These results suggest that Cheongyang pepper extract and its active ingredients have antioxidant and whitening effects, and the possibility of future development as a whitening functional cosmetic material.