• International Journal of Naval Architecture and Ocean Engineering
• /
• v.7 no.1
• /
• pp.195-211
• /
• 2015

Flat plate friction lines have been used in the process to estimate speed performance of full-scale ships in model tests. The results of the previous studies showed considerable differences in determining form factors depending on changes in plate friction lines and Reynolds numbers. These differences had a great influence on estimation of speed performance of full-scale ships. This study was conducted in two parts. In the first part, the scale effect of the form factor depending on change in the Reynolds number was studied based on CFD, in connection with three kinds of friction resistance curves: the ITTC-1957, the curve proposed by Grigson (1993; 1996), and the curve developed by Katsui et al. (2005). In the second part, change in the form factor by three kinds of friction resistance curves was investtigated based on model tests, and then the brake power and the revolution that were finally determined by expansion processes of full-scale ships. When three kinds of friction resistance curves were applied to each kind of ships, these were investigated: differences between resistance and self-propulsion components induced in the expansion processes of full-scale ships, correlation of effects between these components, and tendency of each kind of ships. Finally, what friction resistance curve was well consistent with results of test operation was examined per each kind of ships.

• Journal of the Korean Society of Food Culture
• /
• v.21 no.4
• /
• pp.414-419
• /
• 2006

The purpose of this study was to measure the factor influencing tourist preferences for leaf mustard iimchi. Among 250 questionnaires, 230 questionnaires were utilized for the analysis. Frequencies, conjoint model, max. utility model, BTL model, Logit model, K-means cluster analysis, and one-way ANOVA analysis were used for this study. The findings from this study were as follows. First, the Pearson's R and Kendall's tau statistics showed that the model fitted the data well. Second, it was found that total respondents and three clusters regarded taste and price as the very important factor. Third, it was found that the first cluster most preferred product with light red color, plain package, and mild taste sold at a cheap price in factory. The second cluster most preferred product with light red color, plain package, and moderately pungent taste sold at a expensive price in factory. The third cluster most preferred product with dark red color, shaped package, and highly pungent taste sold at a cheap price in factory. Fourth, it was found that the first cluster most preferred simulation product with light red color, shaped package, and mild taste sold at a cheap price in factory. The second cluster most preferred simulation product with light red color, shaped package, and moderately pungent taste sold at a cheap price in factory. The third clutter most preferred simulation product with dark red color, shaped package, and highly pungent taste sold at a cheap price in factory.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.5
• /
• pp.1153-1164
• /
• 2016

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.6 no.3
• /
• pp.97-102
• /
• 2002

Two dimensional Analysis has been applied to most of tunnel lining design in these days. Two dimensional analysis uses beam or curved beam element for finite element method. But because the behaviors of tunnel concrete lining structure is near to shell, it is required to model the tunnel lining as shell structure for safety design of tunnel lining structure. In this paper, two dimensional analysis by beam element and the three dimensional analysis by shell element of tunnel concrete lining are studied, in which 3 type of tunnel lining and lateral pressure factors are considered. As results of the study, three dimensional analyses of the behavior of tunnel concrete lining structure considering lateral pressure factor shows that the moment of three dimensional analysis is greater than those of two dimensional analysis. The results shows that three dimensional analysis is necessary for safety design of tunnel lining.

• Communications for Statistical Applications and Methods
• /
• v.28 no.5
• /
• pp.521-536
• /
• 2021

As life expectancies increase continuously over the world, the accuracy of forecasting mortality is more and more important to maintain social systems in the aging era. Currently, the most popular model used is the Lee-Carter model but various studies have been conducted to improve this model with one of them being 6-parametric factor model (6-PFM) which is introduced in this paper. To this new model, long short-term memory (LSTM) and regularized LSTM are applied in addition to vector autoregression (VAR), which is a traditional time-series method. Forecasting accuracies of several models, including the LC model, 4-PFM, 5-PFM, and 3 6-PFM's, are compared by using the U.S. and Korea life-tables. The results show that 6-PFM forecasts better than the other models (LC model, 4-PFM, and 5-PFM). Among the three 6-PFMs studied, regularized LSTM performs better than the other two methods for most of the tests.

• Journal of Climate Change Research
• /
• v.7 no.2
• /
• pp.193-203
• /
• 2016

The importance of forecasting agricultural production is receiving attention while climate change is accelerating. This study suggested three types of crop yield forecasting model for major vegetable crops by using downscaled meteorological information of main production area on farmland level, which identified as limitation from previous studies. First, this study conducted correlation analysis with seven types of farm level downscaled meteorological informations and reported crop yield of main production area. After, we selected three types of meteorological factors which showed the highest relation with each crop species and regions. Parameters were deducted from meterological factor with high correlation but crop species number was neglected. After, crop yield of each crops was estimated by using the three suggested types of models. Chinese cabbage showed high accuracy in overall, while the accuracy of daikon and onion was quiet revised by neglecting the outlier. Chili and garlic showed differences by region, but Kyungbuk chili and Chungnam, Kyungsang garlic appeared significant accuracy. We also selected key meteorological factor of each crops which has the highest relation with crop yield. If the factor had significant relation with the quantity, it explains better about the variations of key meteorological factor. This study will contribute to establishing the methodology of future studies by estimating the crop yield of different species by using farmland meterological information and relatively simplify multiple linear regression models.

• Journal of Advanced Marine Engineering and Technology
• /
• v.29 no.7
• /
• pp.736-743
• /
• 2005

In this study, three different types of mechanical ventilation systems are compared based on their ventilation characteristics: tracer gas concentration decay characteristics, and ventilation effectiveness by calculating actual ventilation air flow rate. The experiments are performed by using a step-down method for measuring tracer gas. $CO_{2}$ gas, concentration in the model chamber. Application of a mixing factor, k, was used and measured values ranged from 0.68 to 0.77. The Type 2 ventilation system was found to have the highest ventilation effectiveness rather than the Types 1 and 3.

• Journal of Ginseng Research
• /
• v.33 no.3
• /
• pp.240-243
• /
• 2009

To better understand how to increase a ginseng grower's revenue, a 4-factor revenue determination model (RDM) of raw ginseng production (R=A Y Q P) was proposed. The total revenue (R) is a multiplicative function of four factors: cultivation area(A), unit yield (Y), quality grade (Q) and unit price (P). The A appears to be a pure capital factor. Y and Q are technological factors and P is social and market factor. When P is constant, the technological term (YQ) is the revenue per unit area (R/A) production efficiency per capital. The RDM appears to be a linear model between R and A with the slope [YQ]. RDM was applied to three farmers' raw ginseng production for assessment of its dependency on capital and technological factors.

• The Research Journal of the Costume Culture
• /
• v.22 no.2
• /
• pp.273-289
• /
• 2014

The purpose of this study is to identify the determinants of the susceptibility of global consumer culture. As determinants, materialism and self monitoring as psychological variables and fashion clothing product knowledge as clothing-related variable were included. It was hypothesized that both psychological variables and clothing-related variable influence susceptibility of global consumer culture. Data were gathered by surveying university students in Seoul metropolitan area, using convenience sampling, and 311 questionnaires were used in the statistical analysis. In analyzing data, exploratory factor analysis using SPSS and confirmatory factor analysis and path analysis using AMOS were conducted. Factor analysis of susceptibility of global consumer culture revealed four dimensions, 'social prestige' factor, 'quality perception' factor, 'conformity to others' factor, and 'conformity to consumption trend' factor. In addition, factor analysis of self monitoring revealed three dimensions, 'center-oriented attention' factor, 'situation-appropriate self-presentation' factor, and 'strategic displays of self-presentation' factor. The results showed that all the fit indices for the variable measures were quite acceptable. In addition, the overall fit of the model suggests that the model fits the data well. Tests of the hypothesized path show that all variables except for the one factor of self monitoring, 'center-oriented attention', and materialism influence all the factors of susceptibility of global consumer culture. The implications of these findings and suggestions for future study are also discussed.

• Wind and Structures
• /
• v.31 no.4
• /
• pp.311-319
• /
• 2020

India is a developing nation and heavily spends on the development of wind power plants to meet the national energy demand. The objective of this paper is to investigate wind power potential of Ennore site using wind data collected over a period of two years by three parameter Weibull distribution. The Weibull parameters are estimated using maximum likelihood, least square method and moment method and the accuracy is determined using R² and root mean square error values. The site specific capacity factor is calculated by the mathematical model developed by three parameter Weibull distribution at different hub heights above the ground level. At last, the wind energy economic analysis is carried out using capacity factor at 30 m, 40 m and 50 m height for different wind turbine models. The analysis showed that the site has potential to install utility wind turbines to generate energy at the lowest cost per kilowatt-hour at height of 50 m. This research provides information of wind characteristics of potential sites and helps in selecting suitable wind turbine.