• Geomechanics and Engineering
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• v.3 no.3
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• pp.189-206
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• 2011

Amplification based on empirical relations is widely used for seismic microzonation of urban centers. Amplifications are used to represent the site effects of a particular soil column. Many empirical correlations are available to estimate the amplification of seismic waves. These correlations are based on the ratio of shear wave velocity of foundation/rock to soil velocity or 30 m equivalent shear wave velocity ($Vs^{30}$) and are developed considering deep soil data. The aim of this work is to examine the applicability of available amplification relations in the literature for shallow engineering bedrock sites by carrying out site response studies. Shear wave velocity of thirteen sites having shallow engineering bedrock have been selected for the study. In these locations, the depth of engineering bedrock (> 760 ${\pm}$ 60 m/s) is matched with the drilled bore hole. Shear wave velocity (SWV) has been measured using Multichannel Analysis of Surface Wave survey. These sites are classified according to the National Earthquake Hazards Reduction Program (NEHRP) classification system. Amplifications for an earthquake are arrived for these sites using empirical relations and measured SWV data. Site response analysis has been carried out in SHAKE using SWV and using synthetic and real earthquake data. Amplification from site response analysis and empirical relations are compared. Study shows that the amplification arrived using empirical relations does not match with the site response amplification. Site response amplification is much more than empirical values for same shear wave velocity.

• Tunnel and Underground Space
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• v.13 no.4
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• pp.260-269
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• 2003

In order to introduce to engineers the suitable calculation techniques of TBM advance rate (ad.) and ultimately promote to understand the designing process, this study was carried out. We analyzed the 17 bored data of TBM which applied to the roadway and water supply tunnels in Korea. From this analysis, it was able to how that the average utilization is 30.83% md the correlation equation of Ad and TBM´s diameter (D) is Ad(m/month) = 506.05ㆍ $e^{-0.1162}$$\times$D than the correlation coefficient ($R^2$) is 0.76. In the object of the W tunnel of Seoul-Busan highspeed railway, the Ad of TBM 5.0mø was analyzed by the variety of empirical models and upper correlation equation. Average Ad of the empirical models was calculated to be larger than one of the upper equations. But considering only the results of 3.0~5.0mø TBM in the 17 bored data, the average Ad by the models belongs to the similar range of bored data. Therefore, when the reliability and representative of parameters are decreased, a reliability test should be carried out through the comparison a variety of empirical models with the upper correlation equation.

• Asia-Pacific Journal of Business
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• v.5 no.1
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• pp.1-11
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• 2014

The study provides new empirical evidence on the level of profit efficiency and returns to scale of the Bangladesh banking sector. We employ the Slack-Based Data Envelopment Analysis (SBM-DEA) method to assess the level of profit efficiency of individual banks over the years 2004 to 2011. The empirical findings indicate that the Bangladesh banking sector has exhibited the highest and lowest level of profit efficiency during years 2004 and 2011 respectively. We find that only eight banks have been profit efficient throughout the period under study. The empirical findings seem to suggest that most of the Bangladesh banks have been experiencing economies of scale due to being at less than the optimum size, or diseconomies of scale due to being at more than the optimum size. Thus, decreasing or increasing the scale of production could result in cost savings or efficiencies.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.3
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• pp.307-313
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• 2021

In this study, the comparative analysis, among the design standard value of distribution power, the calculated value from the measurement data of strand and the empirical data of the distribution line itself, have been performed for the elastic coefficients and linear expansion coefficients of distribution line conductors. The empirical values of elastic coefficients were lower about 10.6%(892kgf/mm²) than those of the design standard value of the distribution power and there were a little difference between the empirical values of linear expansion coefficients and the design standard value of the distribution power. From the above results, it could be concluded that the empirical values of conductor characteristics should be used in the dip design and installation of distribution line.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.4
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• pp.244-252
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• 2014

EOF (Empirical Orthogonal Function) analysis is applied to investigate the sand movement in Hujeong Beach. For the analysis, the profile data which were observed five times from June 2009 to May 2010 along the 13 baselines were used. To secure the temporal and physical consistency among the 13 profile data, the 13 profile data were combined into one data and using this data the EOF analysis was performed. According to the analysis, the first EOF is related with the mean topography and the second EOF represents the natural variation of sediment migration and the third EOF is related with the along-shore sediment transport arising from storm. The remaining EOFs show no special relation with wave conditions. In conclusion the main factors which are having great effects on Hujeong Beach's sand movement are analyzed as natural variation and along-shore sediment transport owing the wave conditions.

• Journal of the Korean Data and Information Science Society
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• v.8 no.1
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• pp.21-30
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• 1997

In accelerated life tests, the failure time of an item is observed under a high stress level, and based on the time the performances of items are investigated at the normal stress level. In this paper, when the mean of the prior of a failure rate is known in the exponential lifetime distribution with censored accelerated failure time data, we utilize the empirical Bayesian method by using the moment estimators in order to estimate the parameters of the prior distribution and obtain the empirical Bayesian predictive density and predictive intervals for a future observation under the normal stress level.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3417-3426
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• 2012

This study aims to determine how ownership structure (share-holding ratio of insiders, foreigners) affects agent costs (the portion of asset efficiency or non-operating expenses) through empirical analysis. However, as existing studies on correlations between ownership structure and agent costs adopted Pooled OLS Model, this study focused on additionally formulating Fixed Effect Model and Random Effect Model aimed to reflect the time of data formation and corporate effects as study models based on verification results on the suitability of Pooled-OLS Model before comparative analysis for the purpose of improvement of credibility and statistical validity of the results of empirical analysis based on the premise that the Pooled OLS Model is not reliable enough to verify massive panel data. The data has been accumulated over 10 years from 1998 to 2007 after the IMF crisis hit the nation, from a subject 331 companies except for financial institutions. As a result of the empirical analysis, verification of the suitability of model has determined that the Random Effect Model is appropriate in terms of asset efficiency among agent costs items. On the other hand, the Fixed Effect Model is appropriate in terms of non-operating costs. As a result of the empirical analysis according to the appropriate model, no hypothesis adopted in the Pooled OLS Model has been accepted. This suggests that developing an appropriate model is more important than other factors for the purpose of generating statistically significant empirical results by showing that different empirical results are produced according to the type of empirical analysis.

• Journal of the Korea Safety Management & Science
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• v.24 no.4
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• pp.149-156
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• 2022

Manufacturing process mining performs various data analyzes of performance on event logs that record production. That is, it analyzes the event log data accumulated in the information system and extracts useful information necessary for business execution. Process data analysis by process mining analyzes actual data extracted from manufacturing execution systems (MES) to enable accurate manufacturing process analysis. In order to continuously manage and improve manufacturing and manufacturing processes, there is a need to structure, monitor and analyze the processes, but there is a lack of suitable technology to use. The purpose of this research is to propose a manufacturing process analysis method using process mining and to establish a manufacturing process mining system by analyzing empirical data. In this research, the manufacturing process was analyzed by process mining technology using transaction data extracted from MES. A relationship model of the manufacturing process and equipment was derived, and various performance analyzes were performed on the derived process model from the viewpoint of work, equipment, and time. The results of this analysis are highly effective in shortening process lead times (bottleneck analysis, time analysis), improving productivity (throughput analysis), and reducing costs (equipment analysis).

• Earthquakes and Structures
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• v.25 no.6
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• pp.429-442
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• 2023

To study the seismic vulnerability of the composite material structure of adobe and timber, we collected and statistically analysed empirical observation samples of 542,214,937 m² and 467,177 buildings that were significantly impacted during the 179 earthquakes that occurred in mainland China from 1976 to 2010. In multi-intensity regions, combined with numerical analysis and a probability model, a non-linear continuous regression model of the vulnerability, considering the empirical seismic damage area (number of buildings) and the ratio of seismic damage, was established. Moreover, a probability matrix model of the empirical seismic damage mean value was provided. Considering the coupling effect of the annual and seismic fortification factors, an empirical seismic vulnerability curve model was constructed in the multiple-intensity regions. A probability matrix model of the mean vulnerability index (MVI) was proposed, and was validated through the above-mentioned reconnaissance sample data. A matrix model of the MVI of the regions (19 provinces in mainland China) based on the parameter (MVI) was established.

• Journal of Korean society of Dental Hygiene
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• v.23 no.4
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• pp.303-309
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• 2023

Objectives: According to the Korea Education Development Institute, the college admission quota is expected to exceed the number of high school graduates, leading to an anticipated expansion in the gap between them. This paper aims to conduct an empirical analysis of the variables previously studied, with a specific focus on the admission competition rate for the department of dental hygiene. Methods: The research methodology is the multiple linear regression analysis. The research data contains the structured data from academy information, and the web-based unstructured data collected over the past 3 years. Results: After conducting the analysis, it was newly discovered that the university's online recognition and its location in the metropolitan area were statistically significant factors influencing the admission competition rate for the department of dental hygiene. Conclusions: The findings of this study are expected to be helpful in formulating admission strategies for universities to attract new students and identifying the factors that influence student attraction.