• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.1
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• pp.11-20
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• 2003

In this paper we examine several methods tor calculating the reflection of irregular waves from a perforated-wall caisson breakwater using a regular wave model. The first method is to approximate the irregular waves as a regular wave whose height and period are the same as the root-mean-squared wave height and significant wave period, respectively, of the irregular waves. The second is to use the regular wave model, repeatedly, for each frequency component of the irregular wave spectrum. The wave period is determined according to the frequency of the component wave, and the root-mean-squared wave height is used for all the frequencies. The third method is the same as the second one except that the wave height corresponding to the energy of each component wave is used. Comparison with experimental data from previous authors shows the second method is the most adequate, giving reasonable agreement in both frequency-averaged reflection coefficients and reflected wave spectra.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.97-100
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• 2006

This study performed numerical analysis for obtaining optimal frequency and damping ratio of tuned mass damper (TMD) using 20 seismic loads measured at rock site. The structures of $1{\sim}2$ second natural period were considered, and optimal frequency and damping ratio were estimated for different mass ratio in terms of displacement and absolute acceleration response control. Numerical results showed that the values of the optimal parameters were different those from previous study by Hartog.

• Journal of the Korean Data and Information Science Society
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• v.25 no.1
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• pp.245-254
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• 2014

The traditional methods of simulating daily precipitation have paid little attention to the inherent dependence structure between the total precipitation amount and the precipitation frequency for a fixed period of time. To address this issue, we propose a new simulation algorithm using copula in order to incorporate the dependence into the traditional methods. The algorithm consists of two parts: First, while reflecting the observed dependence, we generate the total precipitation amount (S) and the frequency (N) during the period of interest; then we simulate the daily precipitation whose aggregation matches the pair of (N; S) generated in the first part. Our result shows that the proposed method substantially improves the traditional methods.

• Fashion & Textile Research Journal
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• v.6 no.5
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• pp.558-564
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• 2004

The purpose of this study was to examine the design characteristics of women's swimwear from 1955 to 1969 in Korea using documentary research sources. Both visual and linguistic elements found in the illustrations and advertisements that appeared in periodicals from 1955 to 1969 were used as primary sources. The primary sources were 아리랑, 여상, 여성계, 여성동아, 여원, 주부생활. The methods of content analysis and frequency seriation were combined to analyze the data obtained from the primary sources. Seriational analysis of the data were performed by ordering the frequency chronologically for the entire fifteen-year period. As the result of the study, it was found that the design of the swimwear during this period changed consistently in terms of swimwear type, shape of thigh line, textile design and decorative details. The degree of skin exposure was also continuously increased in different body parts.

• Journal of Korea Trade
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• v.24 no.5
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• pp.71-86
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• 2020

Purpose - This study investigates research trends by searching for English keywords and abstracts in 1,511 Korean journal articles in the Korea Citation Index from the 2002-2019 period using the term "Port." The study aims to lay the foundation for a more balanced development of port research. Design/methodology - Using abstract and keyword data, we perform frequency analysis and word embedding (Word2vec). A t-SNE plot shows the main keywords extracted using the TextRank algorithm. To analyze which words were used in what context in our two nine-year subperiods (2002-2010 and 2010-2019), we use Scattertext and scaled F-scores. Findings - First, during the 18-year study period, port research has developed through the convergence of diverse academic fields, covering 102 subject areas and 219 journals. Second, our frequency analysis of 4,431 keywords in 1,511 papers shows that the words "Port" (60 times), "Port Competitiveness" (33 times), and "Port Authority" (29 times), among others, are attractive to most researchers. Third, a word embedding analysis identifies the words highly correlated with the top eight keywords and visually shows four different subject clusters in a t-SNE plot. Fourth, we use Scattertext to compare words used in the two research sub-periods. Originality/value - This study is the first to apply abstract and keyword analysis and various text mining techniques to Korean journal articles in port research and thus has important implications. Further in-depth studies should collect a greater variety of textual data and analyze and compare port studies from different countries.

• The Journal of Korean Medicine
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• v.32 no.4
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• pp.139-148
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• 2011

Objective: The purpose of this study was to investigate the effect of food intake on the Fourier components of radial pulse wave. Methods: Thirty-one healthy male subjects participated in this study. Radial pulse was measured using 3 dimensional pulse imaging system (DMP-3000) before, right after, 40 minutes after, 80 minutes after and 120 minutes after food intake. Fourier transform was performed and the frequency and amplitude of Fourier components were analyzed. Results: 1. The frequency and the amplitude of Fourier components of radial pulse wave increased significantly after food intake. 2. The frequency of Fourier components increased right after food intake and then gradually decreased as time passed, however the amplitude of Fourier components increased and maintained certain levels and patterns throughout the experimental period of 120 minutes. 3. The change ratios of the frequency and the amplitude of Fourier components after food intake varied with the pulse measuring locations. Conclusions: Food intake exerts an influence on radial pulse wave, resulting in increase of frequency and amplitude of Fourier components. The change ratios of the frequency and the amplitude of Fourier components after food intake varied with the pulse measuring locations.

• Journal of the Korean Society of Safety
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• v.29 no.2
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• pp.76-81
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• 2014

Railroad traffic accident consists of train accident, level-crossing accident, traffic death and injury accident caused by train or vehicle, and it is showing a continuous downward trend over a long period of time. As a result of the frequency comparison of train accidents and level-crossing accidents using the railway accident statistics data of Railway Industry Information Center, the share of train accident is over 90% in the 1990s and 80% in the 2000s more than the one of level-crossing accidents. In this study, we investigated time series characteristic and short-term prediction of railroad crossing, as well as seasonal characteristic. The analysis data has been accumulated over the past 20 years by using the frequency data of level-crossing accident, and was used as a frequency data per month and year. As a result of the analysis, the frequency of accident has the characteristics of the seasonal occurrence, and it doesn't show the significant decreasing trend in a short-term.

• Journal of the Korean Society for Library and Information Science
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• v.49 no.1
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• pp.129-148
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• 2015

This study grasped the true nature of the inquiry domain by analysing the requests for collaborative reference service in the social science field using the co-word technique, and schematized the intellectual structure. First, this study extracted 748 uncontrolled keywords from inquiries for reference in the field of social science. Second, calculated similarity indices between the words on the basis of co-occurrence frequency, and performed not only clustering but also MDS mapping. Third, to grasp the difference in inquiries for reference by period, dividing the period into two parts, and performed comparative analysis. As a result, there formed 5 clusters and "Korea Education" showed an overwhelming size with 40.3% among those clusters. The result of the analysis through the period division showed there were many questions about "Education" during the first half, while a lot of inquiries with focus on "welfare and business information" during the second half.

• Journal of the Korean Home Economics Association
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• v.24 no.4
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• pp.139-146
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• 1986

The purpose of this study was to identify aesthetic concepts of‘Sarangbang’furniture during the Yi-dynasty period and aesthetic descriptions indicating each concept expressed by experts in traditional furniture. The furniture selected for the study includes desks, table bookcases, document and stationary boxes (mungab), letter holders (Kobi) and inkstone boxes (younsang) with lacquer and oil finish on. The respondents were 72 traditional furniture experts; researchers collectors, sellers and artists related to period furniture. The important points of aesthetic descriptors were collected 123 from related literature. From experts' answers, 47 representative descriptors were selected. Data were analyzed with the SPSS using frequency, Percentage mean, factor analysis, t-test and C2. The results were as follows; 1. The aesthetic concept of sarangbang furniture during the Yi-dynasty can be categorized into 9 aspects; appearance of beauty, stability the interior space, naturalness, nobleness/harmony of lines, detail/refinement, simplicity, diversity solidity and surface division. 2. The characteristics of the Korean traditional furniture can be described using 47 descriptors explaining 9 concepts mentioned above.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.313-317
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• 2001

The approach to predict time series without neglecting the fluctuation in a short period is tried by using a digital FIR filter and a neural network. The differential waveform of the Nikkei average closing price is filtered by the FIR band-pass filter of 101 length. It is filtered into the five frequency bands of 0-1Hz, 1-2Hz, 2-3Hz, 3-4Hz and 4-5Hz by setting the sampling frequency 10Hz. The each filtered waveform is learned and forecasted by the neural network. The neural network of the back propagation method is adopted in the learning the waveform. By inputting the data of 20 days in the past, the prediction of 10 days ahead is carried out. After learning the time series of each frequency band by the neural network, the predicted data far each frequency band are obtained. The predicted waveforms of each frequency band are synthesized to obtain a final forecast. The waveform can be forecasted well as a whole.