• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.3
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• pp.171-176
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• 2016

The distribution shapes of air and water temperatures are basic and essential information, which determine the frequency patterns of their occurrence. It is also very useful to understand the changes in long-term air and water temperatures with respect to climate change. The typical distribution shapes of air and water temperatures cannot be well fitted using widely used/accepted normal distributions because their shapes show multimodal distributions. In this study, Gaussian mixture distributions and kernel distributions are suggested as the more suitable models to fit their distribution shapes. Based on the results, the tail shape exhibits different patterns. The tail is long in higher temperature regions of water temperature distribution and in lower temperature regions of air temperature distribution. These types of shape comparisons can be useful to identify the patterns of long-term air and water temperature changes and the relationship between air and water temperatures. It is nearly impossible to identify change patterns using only mean-temperatures and normal distributions.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.3
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• pp.408-418
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• 2015

This study investigates the purchasing and wearing conditions of wetsuits, and analyzes consumer awareness on wetsuit functional factors between domestic and imported brands. This research provides basic information on presenting competitiveness and developing suitable wetsuits for the Korean body shape through an investigation of a size system. An in-depth interview was conducted to consider consumer awareness with 10 persons of different levels of scuba diving experience. The survey variables consist of classified suggestion of inquires for functional factors and size systems. We distributed 80 questionnaires to scuba diving club members; subsequently, a total of 66 usable data sets were coded for statistical analysis through SPSS WIN 18.0. The result shows that respondents preferred imported ready-to-wear brands, whereas national ready-to-wear brands were purchased less often. However, the difference in customer awareness of functional factors between domestic and imported brands was not significant. In evaluating the size system of six brands (including three domestic and three imported brands), wetsuits of domestic brands were better fitted to the Korean body shape than imported brands; however, competitiveness has been hindered by public perception that domestic brands imitate imported brands. The results suggest that domestic brands can strengthen their competitiveness through promoting a lower price and size suited to Koreans while trying to change public perception as imitators of imported brands.

• Journal of Korea Multimedia Society
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• v.9 no.5
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• pp.658-670
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• 2006

As the educational media tends to be more digitalized and individualized, the learning paradigm is dramatically changing into e-learning. Existing on-line courseware gives a learner more chances to learn when they are home with their own PCs. However, it is of little use when they are away from their digital media. Also, it is very labor-intensive to convert the original off-line contents to on-line contents. This paper proposes education mobile contents(EMC) that can supply the learners with dynamic interactions using various multimedia information by recognizing real images of off-line contents using mobile devices. Content-based image retrieval based on object shapes is used to recognize the real image, and shapes are represented by differential chain code with estimated new starting points to obtain rotation-invariant representation, which is fitted to computational resources of mobile devices with low resolution camera. Moreover we use a dynamic time warping method to recognize the object shape, which compensates scale variations of an object. The EMC can provide learners with quick and accurate on-line contents on off-line ones using mobile devices without limitations of space.

• Journal of The Korean Astronomical Society
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• v.39 no.3
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• pp.73-80
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• 2006

We analyze the extinction law towards several B1V stars-members of our Galaxy, searching for possible discrepancies from the galactic average extinction curve. Our photometric data allow to build extinction curves in a very broad range: from extreme UV till infrared. Two-colour diagrams, based on the collected photometric data from the ANS UV satellite, published UBV measurements and on the infrared 2MASS data of the selected stars, are constructed. Slopes of the fitted straight lines are used to build the average extinction curve and to search for discrepant objects. The selected stars have also been observed spectroscopically from the Terskol and ESO Observatories; these spectra allow to check their Sp/L's. The spectra of only about 30% of the initially selected objects resemble closely that of HD144470, considered as the standard of B1 V type. Other spectra either show some emission features or belong clearly to another spectral types. They are not used to build the extinction curve. Two-colour diagrams, constructed for the selected B1 V stars, showing no emission stellar features, prove that the interstellar extinction law is homogeneous in the Galaxy. Both the shape of the curve and the total-to-selective extinction ratio do not differ from the galactic average and the canonical value(3.1) respectively. The circumstellar emissions usually cause some discrepancies from the average interstellar extinction law; the discrepancies observed in the extraterrestrial ultraviolet, usually follow some misclassifications.

• Journal of KSNVE
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• v.9 no.4
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• pp.769-777
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• 1999

Research on vibration of a vehicle with a transversely mounted 4-cylinder engine was performed using a vector synthesis method, Data of the engine vibration for the vector synthesis method was obtained experimentally and the data was ODS-fitted to calculate vibration level on any engine location assuming that the engine is rigid body in the frequency range of interest. In order to derive the excitation force on the vehicle body, the displacements were converted from the acceleration of engine. The transfer functions from engine mounts to toe pan on the floor were obtained experimentally. The vibration level on the toe pan was predicted by multiplying the excitation force by the transfer function. The predicted vibration level was compared with experimental data and the result was reasonable. Using the developed method, analysis was made for the effect of body fixture conditions of the vehicle when testing the engine vibration and for the effect of the transfer functions when the engine is installed or when the engine is removed. Finally the degree of contribution for 12 transfer paths was calculated.

• Wind and Structures
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• v.34 no.6
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• pp.469-482
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• 2022

The generalized extreme value distribution (GEVD) is frequently used to fit the block maximum of environmental parameters such as the annual maximum wind speed. There are several methods for estimating the parameters of the GEV distribution, including the least-squares method (LSM). However, the application of the LSM with the expected order statistics has not been reported. This study fills this gap by proposing a fitting method based on the expected order statistics. The study also proposes a plotting position to approximate the expected order statistics; the proposed plotting position depends on the distribution shape parameter. The use of this approximation for distribution fitting is carried out. Simulation analysis results indicate that the developed fitting procedure based on the expected order statistics or its approximation for GEVD is effective for estimating the distribution parameters and quantiles. The values of the probability plotting correlation coefficient that may be used to test the distributional hypothesis are calculated and presented. The developed fitting method is applied to extreme thunderstorm and non-thunderstorm winds for several major cities in Canada. Also, the implication of using the GEVD and Gumbel distribution to model the extreme wind speed on the structural reliability is presented and elaborated.

• Journal of Biosystems Engineering
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• v.11 no.1
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• pp.76-85
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• 1986

This study was intended to examine the failure characteristics and breakdowns of the head-fed type combines generally used on farms. The failure distribution was assumed to follow Weibull distribution function and the Weibull parameters of the major parts, units and combine as whole were estimated by using the data collected in a survey. A computer program for the estimation of the Weibull parameter was developed. Monte Carlo method was used in predicting the time between failures. The results of study may be summarized as follows: 1. The number of failures per combine was 4.83 times per year and 0.3 times per hectare of combines of different ages. 2. According to the Kolmogorov-Smirnov test method, it was proved that the Weibull distribution function is well fitted to the characteristics of the failure and breakdowns of combines. 3. Weibull parameters of failure distribution of the combine as a whole were estimated to give the shape parameter ${\beta}$=1.3089 and the scale parameter ${\alpha}$=105.2409. The combining area with 80% reliability was 1.1 ha, and the probability of operating the combine without any failure for a year, was $2.76{\times}10^{-4}$. 4. The mean time between failures (MTBF) of the combines was predicted to be 3.2 ha of operation, which corresponds to 32 hours of operation.

• Journal of Korean Society of Forest Science
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• v.99 no.2
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• pp.204-212
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• 2010

This study was performed in 22 unthinned Larix olgensis plantations in northeast China. Data were collected on 95 sample trees of different canopy positions and the diameter at breast height ($d_{1.3}$) ranged from 5.7 cm to 40.2 cm. The individual tree models for the prediction of vertical distribution of live crown, branch and needle biomass were built. Our study showed that the crown, branch and needle biomass distributions were most in the location of 60% crown length. These results were also parallel to previous crown studies. The cumulative relative biomass of live crown, branch and needle were fitted by the sigmoid shape curve and the fitting results were quite well. Meanwhile, we developed the crown ratio and width models. Tree height was the most important predictor for crown ratio model. A negative competition factor, ccf and bas which reflected the effect of suppression on a tree, reduced the crown ratio estimates. The height-diameter ratio was a significant predictor. The higher the height-diameter ratio, the higher crown ratio is. Diameter at breast height is the strongest predictor in crown width model. The models can be used for the planning of harvesting operations, for the selection of feasible harvesting methods, and for the estimation of nutrient removals of different harvesting practices.

• Journal of The Korean Astronomical Society
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• v.44 no.2
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• pp.59-65
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• 2011

A small number of active galactic nuclei are known to exhibit prominent double peak emission profiles that are well-fitted by a relativistic accretion disk model. We develop a Monte Carlo code to compute the linear polarization of a double peaked broad emission line arising from Thomson scattering. A Keplerian accretion disk is adopted for the double peak emission line region and the geometry is assumed to be Schwarzschild. Far from the accretion disk where flat Minkowski geometry is appropriate, we place an azimuthally symmetric scattering region in the shape of a spherical shell sliced with ${\Delta}{\mu}=0.1$. Adopting a Monte Carlo method we generate line photons in the accretion disk in arbitrary directions in the local rest frame and follow the geodesic paths of the photons until they hit the scattering region. The profile of the polarized flux is mainly determined by the relative location of the scattering region with respect to the emission source. When the scattering region is in the polar direction, the degree of linear polarization also shows a double peak structure. Under favorable conditions we show that up to 0.6% linear polarization may be obtained. We conclude that spectropolarimetry can be a powerful probe to reveal much information regarding the accretion disk geometry of these active galactic nuclei.

• Journal of the Korean Home Economics Association
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• v.40 no.10
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• pp.177-189
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• 2002

The purpose of this study was to develop a suitable jacket pattern for elderly women. The subjects were two women of the ages of 65-70, who had different bust size. To reflect the ready made pattern drafting systems, 4 industrial patterns were selected. After analyzing the problems of these patterns, a new jacket pattern was proposed. The results were as follows : 1) The amount of appropriate ease in fitted jacket for elderly women was about 10cm at the bust circumference, 10∼12cm at the hip circumference and the height of sleeve cap was AH/3+0.5cm. 2) Considering an enlargement of waist and abdomen, difference between front and back size was 2cm on the bust line, 6-8cm on the waist and hip line. 3) Because of the shape of concavity of back-waist, center back line in the pattern was folded by 0.5cm from center back waist toward side seam for manipulation. 4) The new jacket pattern was compared with the existing pattern through the wearing test by sensory evaluation. It showed that the fit and comfort of experimental pattern was superior to those of the existing pattern.