• Journal of the Ergonomics Society of Korea
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• v.11 no.1
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• pp.13-19
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• 1992

This paper deals with the legibility of Korean characters(Hangeul) on car number licence plates. We focus of the height-width ratio as key factor affecting the legibility in experimental procedures. The results of experiments are; i) For vertica characters, the vest height-width ratio was 1:1 for 3 throuth 5 stroke characters, and 4:5 for 6 and 7 stroke characters. ii) For horizontal characters, the best height-width ratio was 1:1 for 3 through 5 stroke charcters, and 5:4 for 6 and 7 stoke characters.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.69-76
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• 2020

Since the mechanically stabilized earth walls have a form of retaining wall compatible with a narrow section, the geogrid overlaps according to the separation distance between the walls. There is a problem that the overall behavior may occur in the state of being integrated with the stress change due to the interaction of the geogrid. Therefore, a careful approach is required at the design stage, but there are currently no design criteria or guidelines in Korea. This study investigated the optimal reinforcement length ratio according to the retaining wall width to height ratio (width to height ratio, Wb/H) for these back-to-back mechanically stabilized earth walls. Retaining wall width ratio is 1.1H, 1.4H, 1.7H, 2.0H for Case II of the FHWA design standard, and the height is 3.0 m, 5.0 m, 7.0 m, and 10.0 m, which are most commonly applied. Through numerical analysis, the appropriateness of the FHWA design standard and the optimal reinforcement length ratio according to the height of the retaining wall and the width of the retaining wall were proposed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.831-836
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• 1989

It was found that the effect of the friction between the roll and the workpiece on the spread ratio in flat rolling processes varies with the width-to-height ratio and the reduction in height by Tozawa, Oh and kobayashi numerically. In the present study, the barrelling profile accompanying the width spread was predicted by using the energy method proposed by Kato, which is known to be one of the most advanced method for the three dimensional analysis of the rolling process. The modified velocity field was applied to compute the width spread and the result was verified by experiments. the analysis by the energy method gave the result that the spread ratio increases with the friction factor when the width-to-height ratio is 1 and decreases when the ratio is larger then 2, being consistent with the results of Tozawa and Oh. Nevertheless the cold rolling experiment for pure aluminium showed that the spread ratio decreases with the increasing friction factor irrespective of the width-to-hight ratio.

• Journal of the Ergonomics Society of Korea
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• v.6 no.2
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• pp.9-18
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• 1987

The purpose of this study was to find the optimal stroke width-to-height ratio of the Korean character (Hangeul) which yields the greatest reading distance. In this study, black characters on a white background were used under 200 lux conditions in-doors, with the stroke width-to-height ratios ranging from a very thin 1:125 to heavier 1: 8.3. The criterion was the average reading distance at which three subjects (male university students) having normal visual acuity (1.2) could read the characters. Using the data obtained from the experi- ment, we analyzed the relationship between stroke width-to-height ratio and reading distance. In the case of the black characters on a white background, the greatest reading distances occurred with a range from 1:11.4 to 1:17.9.

• Journal of the Korea Fashion and Costume Design Association
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• v.7 no.1
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• pp.33-40
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• 2005

Gathering is method used to control fullness along a seam line. The purpose of this study was to investigate the relationship between the quantitative research and qualitative method; the effect of gather and the types of gather drape. The experimental design consists of four factors: (l) three kinds of different weight and thickness of fabrics (2) three kinds of stitch densities (3) five kinds of ratio of gathers (4) three kinds of grain directions. Therefore one hundred thirty five (135) samples were made. And utilized SPSS WIN 10.0 Package in data analysis. The results of this study were as follows; First, after frequency analysis, side height, hem line width, node depth, node count, node width accorded with these result data recording. Second, after correlation analysis, side height related with front statements. Side height and entire visual was negative correlation. Hem line width, node depth, node count with section statements was negative correlation but node width at section statements was positive correlation. Third, after $k^2$ analysis, front picture parts getting excellent evaluation were 1st side height, 3rd hem line width, 4th node depth, 3rd node count, 3rd node width. And section illustration parts getting excellent evaluation were 4th side height, 1st hem line width, 2nd node depth, 3rd node count, 4th node width.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.6
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• pp.743-752
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• 1998

Experiments were performed to characterize single-phase heat transfer behavior of submerged liquid jet with multiple nozzle normally impinging on the smooth and extended surfaces. Arrays of 9 and 36 nozzles were used, with diameters of 0.5 to 2.0mm providing nozzle area ratio (AR) from 0.05 to 0.2. The square pin fin arrays were chosen as extended surfaces and the effects of geometrical parameters such as fin height, the ratio of fin width to channel width on heat transfer enhancement were examined. Single nozzle characteristics were also evaluated for comparison. The results clearly showed that heat transfer enhancement could be realized by using multiple nozzles at the constant volume flow rate. The average Nusselt number of multiple nozzle impingement on the smooth surface was correlated by the following equation : Nu/$Pr\frac{1}{3}=0.94 Re^{0.56}N^{-0.12}AR^{0.50}$The average heat transfer coefficients of multiple nozzle impingement on the extended surfaces decreased with increasing fin height and the ratio of fin width to channel width. The effectiveness of ex-tended surfaces ranged from 1.5 to 3.5 depending on the fin height, the ratio of fin width to channel width of pin fin arrays, nozzle number and nozzle area ratio.

• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.8
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• pp.523-529
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• 2010

We investigate two-dimensional laminar flow around rectangular cylinders placed in a uniform stream. Numerical simulations are performed, using finite volume method, in the ranges of $50{\leq}Re{\leq}150$ and $0.1{\leq}W/H{\leq}1.0$, where Re and W/H are the Reynolds number and the width-to-height ratio, respectively. The immersed boundary method is used to handle the rectangular cylinder in a rectangular grid system. Comparisons with the previous results show good agreement in Strouhal number, drag and lift coefficient. The present study reports the detailed information of flow structure at different width-to-height ratios in the ranges of $50{\leq}Re{\leq}150$.

• Geomechanics and Engineering
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• v.2 no.1
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• pp.29-44
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• 2010

Vertical vibration tests were conducted using model footings of different size and mass resting on the surface of finite sand layer with different height to width ratios which was underlain by either rigid concrete base, under both dry and saturated condition. The effect of saturation on the damping ratio of finite sand stratum underlain by a rigid base has been verified and compared with the results obtained for the case of finite dry sand stratum underlain by the rigid base. Comparison of results of the experimental study showed that the damping in both the cases is less than 10%. The damping ratio obtained for finite saturated sand stratum is marginally lower than that obtained on finite dry sand stratum at H/B ratio of 0.5. The difference between the two cases becomes significant when the H/B ratio increases to 3.0, indicating the significant influence of soil moisture on damping ratio of foundation- soil system with increase in the thickness of the finite sand stratum. Comparison of the predicted damping ratio for a homogeneous sand stratum with the experimental damping ratio obtained corresponding to the height to width ratio of 3.0 of the finite sand stratum underlain by the rigid concrete base indicates a significant reduction in damping ratio of the foundation-soil system for both the cases.

• The korean journal of orthodontics
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• v.26 no.2 s.55
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• pp.197-204
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• 1996

This study was performed to mark the criteria of the eathetic smile that was necessary to improve the esthetic problem in oral maxillo-facial region. The facial straight photographs of 62 adults(30 males, 32 females : 19-24 years old) in resting position and during smile were taken. The measurements and proportion of lip-teeth relationship during smile were statistically analyzed with photogrammetry. The following results wow obtained : 1. In the evaluation of the change of lips, smile line ratio was 0.93, buccal corridor ratio was 0.63, and smile symmetry ratio was 0.96. 2. The width of mouth during smile was 1.31 times of the width inthe resting position and 0.48 times of face width. 3. The upper lip height during smile was 0.69 times of the height in the resting position and the lower lip height during smile was 0.93 times of the height in the resting position. 4. The mean exposed lenght of upper central incisor was 9.96mm. Maxillary incisor exposure was significantly correlated with the upper lip change ratio, mouth width change ratio, and buccal corridor ratio.