• Fashion & Textile Research Journal
• /
• v.7 no.5
• /
• pp.535-541
• /
• 2005

The health of feet is connected with individual's health and affects a man's activity. Shoes need to be designed to protect feet and to absorb the impact of land. In order to choose suitable shoes for feet, the foot size and shape must be considered, so it is essential to grasp the exact size and shape of the foot. This study aims to present fundamental data on shoes' easy order prototype development for choosing shoes of good wearing comfort, by classifying feet size and shape junior high school boys in the early adolescent period. The subject were 234 Korean junior high school boys age from 14 to 16 years old. The subjects were directly measured anthropometrically and indirectly analyzed photographically. 6 factors were extracted through factor analysis and those factors comprised 79.42% of total variance. The factors characterizing foot girth and width, foot length, foot height, foot shape around the fifth toes, angle of foot breadth and foot shape around the first toes. 3 clusters as their foot shape were categorized using 6 factor scores by cluster analysis. Type 1 was characterized by long large foot with deformed first toe. Type 2 had smaller in foot girth, width and length than other types and with deformed fifth toe. Type 3 had average size and high foot shape. Shoes prototype which is to be developed later on will be able to generate 2D flattening in the foot sole form. Therefore, it would be a great support in producing and choosing appropriate shoes if forms are classified by subdividing foot form classification and extract a factor which shows only the foot sole shape.

• Fashion & Textile Research Journal
• /
• v.9 no.3
• /
• pp.319-326
• /
• 2007

The health of feet is connected with individual's health and affects a man's activity. Shoes need to be designed to protect feet and to absorb the impact of land. In order to choose suitable shoes for feet, the foot size and shape must be considered, so it is essential to grasp the exact size and shape of the foot. This study aims to present fundamental data on shoes' easy order prototype development for choosing shoes of good wearing comfort, by classifying feet size and shape junior high school boys in the early adolescent period. The subject were 217 Korean junior high school girls in age from 14 to 16 years old. The subjects were directly measured anthropometrically and indirectly analyzed photographically. 7 factors were extracted through factor analysis and those factors comprised 78.59% of total variance. The factors were characterized foot length, foot girth and width, foot shape around the fifth toes, foot shape around the first toes, angle of foot breadth, foot height, and foot length of upper foot. 3 clusters as their foot shape were categorized using 7 factor scores by cluster analysis. Type 1 had smaller in foot girth, width and length than other types and with deformed fifth toe. Type 2 had average size and high foot shape. Type 3 was characterized by long large foot with deformed first toe. The results would be a great support in producing and choosing appropriate shoes if forms are classified by subdividing foot form classification and extract a factor which shows only the foot sole shape.

• Steel and Composite Structures
• /
• v.27 no.4
• /
• pp.427-438
• /
• 2018

In this paper, the single and multi-objective optimization of thin-walled conical tubes with different types of indentations under axial impact has been investigated using surrogate models called metamodels. The geometry of tapered thin-walled tubes has been studied in order to achieve maximum specific energy absorption (SEA) and minimum peak crushing force (PCF). The height, radius, thickness, tapered angle of the tube, and the radius of indentation have been considered as design variables. Based on the design of experiments (DOE) method, the generated sample points are computed using the explicit finite element code. Different surrogate models including Kriging, Feed Forward Neural Network (FNN), Radial Basis Neural Network (RNN), and Response Surface Modelling (RSM) comprised to evaluate the appropriation of such models. The comparison study between surrogate models and the exploration of indentation shapes have been provided. The obtained results show that the RNN method has the minimum mean squared error (MSE) in training points compared to the other methods. Meanwhile, optimization based on surrogate models with lower values of MSE does not provide optimum results. The RNN method demonstrates a lower crashworthiness performance (with a lower value of 125.7% for SEA and a higher value of 56.8% for PCF) in comparison to RSM with an error order of $10^{-3}$. The SEA values can be increased by 17.6% and PCF values can be decreased by 24.63% by different types of indentation. In a specific geometry, higher SEA and lower PCF require triangular and circular shapes of indentation, respectively.

• Wind and Structures
• /
• v.30 no.4
• /
• pp.325-338
• /
• 2020

In this paper, the improvement of the anti-snow performance of a high-speed train (HST) is studied using the unsteady Reynolds-Averaged Navier-Stokes simulations (URANS) coupled with the Discrete Phase Model (DPM). The influences of the proposed flow control scheme on the velocity distribution of the airflow and snow particles, snow concentration level and accumulated mass in the bogie cavities are analyzed. The results show that the front anti-snow structures can effectively deflect downward the airflow and snow particles at the entrance of the cavities and alleviate the strong impact on the bogie bottom, thereby decrease the local accumulated snow. The rotational rear plates with the deflecting angle of 45° are found to present well deflecting effect on the particles' trajectories and force more snow to flow out of the cavities, and thus significantly reduce the accretion distribution on the bogie top. Furthermore, running speeds of HST are shown to have a great effect on the snow-resistance capability of the flow control scheme. The proposed flow control scheme achieves more snow reduction for HST at higher train's running speed in the cold regions.

• Journal of Advanced Marine Engineering and Technology
• /
• v.37 no.5
• /
• pp.510-519
• /
• 2013

In this study, the spray characteristics of a pressure swirl atomizer classified into a liquid sheet-type swirl nozzle for Urea-SCR system were investigated experimentally with the variation of injection pressure. The length to diameter ratio ($l_o/d$) of the nozzle was 3.1, and the swirler was set inside the nozzle tip to give injecting fluid angular momentum. The injection duration of the nozzle was controlled by PWM (pulse width modulation) modes. The development processes of the spray were imaged by a 2-D PIV system, and the change of spray angle was measured. The atomization characteristics, including axial velocity and SMD, were measured using a 2-D PDA system with the injection pressures at room temperature and ambient pressure conditions. As the experimental results, the injection pressure had a significant impact on the spray structure showing a different shape around the spray leading edge, and the smaller SMD was observed with increasing injection pressures, which was similar to that of the previous work.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.5 no.4
• /
• pp.31-39
• /
• 2001

Composite propeller shafts for a vehicle have major advantages such as reduction of vibration, noise, and weight. A propeller shaft was designed with a carbon/epoxy composite material using the finite element method(FEM), and prototype shafts for tests were manufactured by the filament winding manufacturing process. In order to verify the design procedure by FEM, Two kinds of experimental tests were carried out using a FFT analyzer with impact hammers and a critical speed measuring apparatus for measurement of natural frequencies and critical speeds. The difference between the FEM analysis result and the test result was less than 3.4%, showing FEM analysis results to be acceptable. The parametric study was focused on determining the factor affecting the vibration and strength characteristics of the propeller shaft based on FEM. In investigation of the change in natural frequency without an increase in propeller shaft weight, it was found that the winding angle is the most significant factor affecting the vibration and strength characteristics.

• Journal of Adhesion and Interface
• /
• v.12 no.4
• /
• pp.144-150
• /
• 2011

The effect of low profile agent and release agent on the surface and mechanical properties of bulk mold compound were investigated. Atomic content and contact angle of surface were characterized using X-ray photoelectron spectroscopy and contact anglemeter. Surface morphology and surface roughness were obtained using field emission scanning electron microscope and atomic force microscope, respectively. As increasing the low profile agent from 0 to 9.2 wt%, the volume shrinkage and surface roughness decreased from 0.35% to 0.05%, and from $0.27{\mu}m$ to $0.12{\mu}m$, respectively. The increase of release agent from 1.8 wt% to 3.6 wt% resulted in the migration of release agent to sample surface and it increased the surface roughness. The flexural strength and impact strength were decreased approximately 30% as the low profile agent increasing from 5.0 wt% to 9.0 wt%.

• Journal of the Korean Solar Energy Society
• /
• v.35 no.2
• /
• pp.93-101
• /
• 2015

Zero energy building is a self sufficient building that minimizes energy consumption through passive elements such as insulation, high performance window system and installing of high efficiency HVAC system and uses renewable energy sources. The Korea Government has been strengthening the building energy efficiency standard and code for zero energy building. The building energy performance is determined by the performance of building envelope. Therefore it is important to optimize facade design such as insulation, window properties and shading, that affect the heating and cooling loads. In particular, shading devices are necessary to reduce the cooling load in summer season. Meanwhile, BIPV shading system functions as a renewable energy technology applied in solar control facade system to reduce cooling load and produce electricity simultaneously. Therefore, when installing the BIPV shading system, the length of shadings and angle that affect the electricity production must be considered. This study focused on the facade design applied with BIPV shading system for maximizing energy saving of the selected standard building. The impact of changing insulation on roof and walls, window properties and length of BIPV shading device on energy performance of the building were investigated. In conclusion, energy consumption and electricity production were analyzed based on building energy simulations using energyplus 8.1 building simulation program and jEPlus+EA optimization tool.

• Water for future
• /
• v.27 no.3
• /
• pp.35-43
• /
• 1994

Because a failure to provide enough plunge pool depth can create a risk to the structural stability of the psillways or dams, many researchers have proposed experimental formulas for claculating ultimate scour depth under jet issued from spillways and pipe culverts. For the design purposes of a plunge pool, scour potential distribution is important as much as the ultimate scour depth is. In this study scour potential distributions near the jet impinging point on a porous plane which can simulate a real cohesionless movable flat bed has been measured. Experimental results showed that scour potential distributions are geometrically similar to each other provided the angle of jet impact was the same. Statistical analysis of experimental results showed that scour potential distributions for the design purposes of a plunge pool could be expressed by a single equation within a range of this experiment. The proposed formula for the prediction of scour potential distributions agrees well with experimental measurements.

• The Korean Journal of Pain
• /
• v.21 no.2
• /
• pp.143-149
• /
• 2008

Background: Traction has often been utilized to treat patients with a herniated lumbar disc. Currently, the most advanced type of traction therapy is non-surgical spinal decompression. Therefore, this study was conducted to evaluate the effectiveness of decompression therapy in patients with a herniated lumbar disc based on clinical findings and symptoms. Methods: Sixty patients with herniated lumbar discs were included in this study. The patients were randomly divided into two groups, a decompression group (n = 30) and a traction group (n = 30). To evaluate the impact of decompression and traction therapy on the herniated disc, the clinical symptoms for each group were evaluated prior to and after treatment using the visual analogue scale (VAS), straight leg raising (SLR), the herniation index, and the disc height. Results: The VAS score was significantly lower in the decompression group ($2.0{\pm}0.2$) than the traction group ($3.9{\pm}0.2$) following treatment. In addition, the SLR angle was significantly higher in the decompression group ($79{\pm}1.5$) than the traction group ($63.3{\pm}1.9$). The herniation index was significantly lower in the decompression group ($217.6{\pm}19.1$) than the traction group ($259.5{\pm}16.4$). Finally, the disc height was not significant differences between pre-treatment and follow-up in two groups. Conclusions: The results of this study suggest that decompression therapy for the treatment of patients suffering from a herniated lumbar disc has an effect on the pain, SLR, and herniation indices, not disc heights.