• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.1-14
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• 1999

In the present study, the flame factor which primarily influence the simulation accuracy of the combustion process in a gasoline engine was modeled as a nonlinear function of turbulent intensity to laminar flame speed ratio. Multi-length-scale production rate model for turbulent kinetic energy equation was introduced to consider the different length scales of the swirling and tumbling motions in cylinder on the production rte of turbulent kinetic energy. By7 introducing the multi-length-scale production rate model for the turbulent kinetic energy equation, the predictions of turbulent burning velocity , cylinder pressure, mass burning rate and engine performance of a gasoline engine can much be improved.

• Journal of Korean Society for Geospatial Information Science
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• v.6 no.2 s.12
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• pp.119-132
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• 1998

Much information on the terrain and the space has been depicted to maps of various form according to the map scale and the application. In Korea the base map system was made by only one projection method(Transvers Mercator projection). This is the reason to study this paper, because I think singular map projection method can't satisfy the various map scales and application. In this paper Meridian Are Length, Parallel Are Length of ellipsoid and the area of ellipsoidal surface-the length, the width and area of the map scale 1/5,000, 1/25,000, 1/5,000, 1/1,000, will be calculated and transformed to the plane length and area by Transvers Mercartor projection and Polyhedrical projection. The projection distortion which came into existence on this occasion was compared and analyzed by this Paper. And Properties on TM and Polyhedrical projection were understood. Lastly this paper intended to present suitable map projections according to the map scales and the purpose of use.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.6
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• pp.1060-1071
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• 1997

The purpose of this study is to identify the effect of clothing cues(sleeve and skirt width, length) on female impressions. The experimental materials developed for this study are a set of stimuli and response scales. The stimuli are 16 pictures manipulated with sleeve and skirt width · length variations by computer drawing. The experimental design consists of 3 factorial design: (1) sleeve shapes(plain, upper expanded, below expanded, all expanded) (2) skirt width (wide, narrow) (3) skirt length(long, short) The 7-point semantic differential response scale designed for visual evaluation of female' s impression formation on sleeve shape and skirt width · length is 27 bipolar adjectives. The results of this study are as follows: 1. When we analize the impressions of female figure by sleeve shape and width · length of skirt, it becomes clear that maturity, modernity, attention, elegance and tenderness are proved to be important. Among these five factors, maturity, modernity and attention are identified as more important ones. 2. Sleeve shape have an effect on all factors except maturity and the effects of sleeve on the four factors are not striking. ' Width of skirt are most influential to the maturity and attention, but it does not have any effect on modernity. However two factor, that is width of skirt and sleeve have an effects on modernity, attention and tenderness. ' The length of skirt has an effects on the tenderness, elegance and modernity, but it dose not have any effect on attention. But width and length of skirt have an effects on attention, tenderness and modernity The length of skirt and sleeve have an effect on tenderness.

• Wind and Structures
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• v.34 no.1
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• pp.137-149
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• 2022

In this paper, the fluctuating lift and drag forces on 5:1 rectangular cylinders with two different geometric scales in three turbulent flow-fields are investigated. The study is particularly focused on understanding the influence of the ratio of turbulence integral length scale to structure characteristic dimension (the length scale ratio). The results show that both fluctuating lift and drag forces are influenced by the length scale ratio. For the model with the larger length scale ratio, the corresponding fluctuating force coefficient is larger, while the spanwise correlation is weaker. However, the degree of influence of the length scale ratio on the two fluctuating forces are different. Compared to the fluctuating drag, the fluctuating lift is more sensitive to the variation of the length scale ratio. It is also found through spectral analysis that for the fluctuating lift, the change of length scale ratio mainly leads to the variation in the low frequency part of the loading, while the fluctuating drag generally follows the quasi-steady theory in the low frequency, and the slope of the drag spectrum at high frequencies changes with the length scale ratio. Then based on the experimental data, two empirical formulas considering the influence of length scale ratio are proposed for determining the lift and drag aerodynamic admittances of a 5:1 rectangular cylinder. Furthermore, a simple relationship is established to correlate the turbulence parameter with the fluctuating force coefficient, which could be used to predict the fluctuating force on a 5:1 rectangular cylinder under different parameter conditions.

• Journal of The Korean Association For Science Education
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• v.17 no.2
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• pp.127-137
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• 1997

The purpose of this study was to assess elementary student's ability of measuring length, area, and volume and reading metric scales. The findings of this study were as follows. All students were successful in measuring without scale, regardless of grades. But they were less successful in measuring the task using standard and nonstandard scales. Especially, in measuring area, lower grade students were not able to perform the task using nonstandard instruments, but higher grade students were able to perform the task. Measuring area using grade paper was least successful for sixth graders. In measuring volume, students under fifth grade read the upper scale when using graduated cylinder. In measuring by direct comparison, students were more successful in measuring length than in measuring area and volume using given material. The use of given nonstandard material was successful for 4th, 5th, and 6th grade students. In measuring using metric scale, lower grade students did not pay attention to the zero of the scale, but just read the end point. Higher grade students considered both zero and end points.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.1
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• pp.55-63
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• 2011

This study presents characteristics of representative five hand dimensions including hand length, medius finger length, hand circumference, hand breadth and hand thickness, and hand scales by gender and age for Koreans. The study was based on data of hand dimensions published in 2008 by Korean Agency for Technology and Standards. The hand dimensions of males were nearly the same as those of females until age of 12~13(10~11 in hand thickness), but the males' were larger than the females' from age group of 14~15 or 12~13. The growth of the hand dimensions was found until age of 12~13(14~15 in hand thickness) in females and 16~17 in males. After the age groups, the hand dimensions was almost the same irrespective of age groups. ANOVA was performed to investigate significant factors affecting hand dimensions. Representative five hand dimensions were significantly affected by gender and age, while they were not affected by occupation. Two hand scales were proposed depending upon gender, for easily using hand characteristics in design stage of hand relevant products. In addition, regression equations were provided for quantitatively predicting hand dimensions on the basis of representative five hand dimensions.

• Wind and Structures
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• v.30 no.3
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• pp.231-243
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• 2020

Downbursts are acknowledged for being a major loading hazard for horizontally-extending structures like transmission line systems. With these structures being inherently flexible, it is important to characterize the turbulence associated with the wind flow of downburst events being essential to quantify dynamic excitations on structures. Accordingly, the current study numerically characterizes the downburst wind field of open terrain simulated at the Wind Engineering, Energy and Environment (WindEEE) dome testing facility at The University of Western Ontario in Canada through a high-resolution large eddy simulation (LES). The study validates the numerical simulation considering both the mean and the turbulent components of the flow. It then provides a detailed visual description of the flow at WindEEE through the capabilities enabled by LES to identify the key factors affecting the flow. The study also presents the spatial distribution of turbulence intensities and length scales computed from the numerical model and compares them with previous values reported in the literature. The comparison shows the ability of the downburst simulated at WindEEE to reproduce turbulence characteristics similar to those reported from field measurements. The study also indicates that downburst turbulence is well-correlated circumferentially which imposes high correlated loads on horizontally-distributed structures such as transmission lines.

• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.11-20
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• 2009

Radiation effects on materials are inherently multiscale phenomena in view of the fact that various processes spanning a broad range of time and length scales are involved. A multiscale modeling approach to embrittlement of pressure vessel steels is presented here. The approach includes an investigation of the mechanisms of defect accumulation, microstructure evolution and the corresponding effects on mechanical properties. An understanding of these phenomena is required to predict the behavior of structural materials under irradiation. We used molecular dynamics (MD) simulations at an atomic scale to study the evolution of high-energy displacement cascade reactions. The MD simulations yield quantitative information on primary damage. Using a database of displacement cascades generated by the MD simulations, we can estimate the accumulation of defects over diffusional length and time scales by applying kinetic Monte Carlo simulations. The evolution of the local microstructure under irradiation is responsible for changes in the physical and mechanical properties of materials. Mechanical property changes in irradiated materials are modeled by dislocation dynamics simulations, which simulate a collective motion of dislocations that interact with the defects. In this paper, we present a multi scale modeling methodology that describes reactor pressure vessel embrittlement in a light water reactor environment.

• Journal of Computing Science and Engineering
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• v.8 no.2
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• pp.119-128
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• 2014

The appearance of retinal blood vessels is an important diagnostic indicator of serious disease, such as hypertension, diabetes, cardiovascular disease, and stroke. Automatic segmentation of the retinal vasculature is a primary step towards automatic assessment of the retinal blood vessel features. This paper presents an automated method for the enhancement and segmentation of blood vessels in fundus images. To decrease the influence of the optic disk, and emphasize the vessels for each retinal image, a multidirectional morphological top-hat transform with rotating structuring elements is first applied to the background homogenized retinal image. Then, an improved multiscale line detector is presented to produce a vessel response image, and yield the retinal blood vessel tree for each retinal image. Since different line detectors at varying scales have different line responses in the multiscale detector, the line detectors with longer length produce more vessel responses than the ones with shorter length; the improved multiscale detector combines all the responses at different scales by setting different weights for each scale. The methodology is evaluated on two publicly available databases, DRIVE and STARE. Experimental results demonstrate an excellent performance that approximates the average accuracy of a human observer. Moreover, the method is simple, fast, and robust to noise, so it is suitable for being integrated into a computer-assisted diagnostic system for ophthalmic disorders.

• Macromolecular Research
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• v.13 no.5
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• pp.435-440
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• 2005

This study describes a method where the match of two different length scales, i.e., the patterns from self-assembled block copolymer (<50 nm) and electron beam writing (>50 nm), allow the nanometer scale pattern mask. The method is based on using block copolymers containing a poly(methyl methacrylate) (PMMA) block, which is subject to be decomposed under an electron beam, as a pattern resist for electron beam lithography. Electron beam on self assembled block copolymer thin film selectively etches PMMA microdomains, giving rise to a polymeric nano-pattern mask on which subsequent evaporation of chromium produces the arrays of Cr nanoparticles followed by lifting off the mask. Furthermore, electron beam lithography was performed on the micropatterned block copolymer film fabricated by micro-imprinting, leading to a hierarchical self assembled pattern where a broad range of length scales was effectively assembled, ranging from several tens of nanometers, through submicrons, to a few microns.