• Journal of the Korean Institute of Gas
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• v.12 no.4
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• pp.34-40
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• 2008

Using the finite element method and Taguchi's design technique, the displacement in vertical direction, von Mises stress, and strain energy of the corrugation damper have been analyzed as functions of the extruded length and the thickness of the corrugation damper, and the upper and lower corner radii of the damper. The optimized profile design elements of a corrugation damper are very important for increasing a strain energy absorption capacity of a helmet structure, which is attacked by impulsive external forces. In this study, the optimized design data based on the Taguchi's method was computed as a corrugation damper length of L = 20 mm, a damper thickness of t = 2 mm, the upper corner radius of $R_1=4\;mm$, and the lower corner radius of $R_2=3\;mm$. The optimized design parameters of a corrugation damper indicated that the thickness and extruded length of a corrugation damper may affect to increase the strain energy, which absorbs the impact forces of the helmet.

• Structural Engineering and Mechanics
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• v.67 no.4
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• pp.347-358
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• 2018

The main aim of this research was to investigate the shear strength of non-prismatic steel fiber reinforced concrete beams under monotonic loading considering different parameters. Experimental program included tests on fifteen non-prismatic reinforced concrete beams divided into three groups. For the first and the second groups, different parameters were taken into consideration which are: steel fibers content, shear span to minimum depth ratio ($a/d_{min}$) and tapering angle (${\alpha}$). The third group was designed mainly to optimize the geometry of the non-prismatic concrete beams with the same concrete volume while the steel fiber ratio and the shear span were left constant in this group. The presence of steel fibers in concrete led to an increase in the load-carrying capacity in a range of 10.25%-103%. Also, the energy absorption capacity was increased due to the addition of steel fibers in a range of 18.17%-993.18% and the failure mode was changed from brittle to ductile. Tapering angle had a clear effect on the shear strength of test specimens. The increase in tapering angle from ($7^{\circ}$) to ($12^{\circ}$) caused an increase in the ultimate shear capacity for the test specimens. The maximum increase in ultimate load was 45.49%. The addition of steel fibers had a significant impact on the post-cracking behavior of the test specimens. Empirical equation for shear strength prediction at cracking limit state was proposed. The predicted cracking shear strength was in good agreement with the experimental findings.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.378-387
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• 2009

To investigate the effects of sago palm pith (SPP) substitution of corn in the diets on intake, digestibility, rumen fermentation characteristics, nitrogen balance and microbial N Supply, five ruminally fistulated Southern indigenous cattle (mean initial BW = 226${\pm}$5 kg) were randomly assigned to a 5${\times}$5 Latin Square Design to receive five diets, $T_1$ = concentrate with 0% SPP, $T_2$ = 25% SPP, $T_3$ = 50% SPP, $T_4$ = 75% SPP and $T_5$ = 100% SPP, of dietary dry matter, respectively. Plicatulum hay (PH) was offered ad libitum as the roughage. A metabolism trial lasted for 21 days during which liveweight changes and feed intakes were measured. Based on this experiment, there were no significant differences (p>0.05) among treatments groups regarding total DM intake (OMI, NDFI and ADFI) and digestion coefficients of nutrients (DM, OM, CP, NDF and ADF), while total DM intake (% BW) was significantly (p<0.05) higher as higher levels of SPP were incorporated into diets. Rumen parameters (ruminal temperature, pH, glucose, packed cell volume, volatile fatty acid and rumen microorganism populations) were similar among treatments (p>0.05), whereas $NH_3-N$, blood urea nitrogen and molar proportion of propionate concentrations were significantly (p<0.05) higher as higher levels of SPP were incorporated into diets. The amount of N absorption, N retention and microbial protein synthesis were similar among treatments. These results indicate that SPP can be included in diets for Southern indigenous cattle to supply up to 100% of supplemental corn when fed with PH without negative impact on animal performance and it was a good approach in exploiting the use of local feed resources for beef cattle production.

• Polymer(Korea)
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• v.34 no.1
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• pp.14-19
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• 2010

Applying acrylic silane monomer for determent of weathering damage of stone cultural assets from various sources was investigated to improve inorganic affinity of polymer impregnated to the stone for conservation treatment using impregnation of acrylic polymers under pressure. Radical polymerization was carried out with various mixture ratios of methacrylate (MMA), as the base monomer, and vinyl trimethoxy silane (VTMS). Subsequently, according to the changes of glass transition temperatures, average molecular weights, and storage moduli of the obtained copolymers, the case of adding 1 wt% of benzoyl peroxide, polymerization for 8 hrs, and mixing 5 mol% of VTMS to MMA was the optimum condition of monomer ratio and polymerization. Practically, fresh granites collected in domestic site and weathered stones were treated by following the obtained result above, and then, the moisture absorption, impact, acid resistance, and adhesion properties of the treated stones were compared to those of the corresponding stones treated with MMA only. It was found that those properties of the stones treated with PMV5 were considerably improved.

• Korean Business Review
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• v.18 no.2
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• pp.45-60
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• 2005

CSA(Control Self Assessment) is a new internal control technique whose objective is to control the human resource performance, the manager's philosophy, the business ethics, the effective communication and decision making etc. The purpose of this study is to find out if the CSA improve the quality of internal control. With the questionnaire method the following conclusions are reached. 1) Level of the management supports influence the level of the workshop participation. 2) Anonymity during the workshop session influences the level of workshop participation. 3) Level of the organizational committment influences the level of the participation 4) The level of workshop performance significantly influences the level of internal contro improvement.

• Journal of Forest and Environmental Science
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• v.36 no.3
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• pp.219-224
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• 2020

Urea formaldehyde resins are widely used in the manufacturing of wood composite and their usage is always combined with release of formaldehyde characterized to be hazardous to health during and after the manufacturing of the products. This study investigates the effectiveness of wood-based adhesive from oil of pyrolysed Triplochiton scleroxylon sawdust for the production of composite board. The wood-derived Pyrolytic Oil (PyO) was blended with Urea Formaldehyde (UF) resin to formed Pyrolytic Oil-Urea Formaldehyde (PyOUF). The obtained PyOUF called Wood-Based Adhesives at four blends and control (UF) viz; 1:1, 1:2, 1:3, 2:1, 1:3 were further employed to prepare the composite board and test for their bonding strength by physical (water absorption-WA and thickness swelling-Th.S) and mechanical properties (modulus of elasticity-MOE, modulus of rupture-MOR, and impact bending-IB). Data obtained was analysed using analysis of variance at α 0.05. The result of analysis of variance conducted on physical properties show significant difference (p≤0.05) between the WA values obtained when testing the different blending proportion of PyOUF and likewise between 2 and 24 h of immersion. PyOUF had significant effect (p≤0.05) on Th. S for 24 h but no significant different (p>0.05) for the 2 h period of soaking. The analysis of variance on mechanical properties of the composite board (MOE, MOR, and IB) show significance differences (p≤0.05) between the strength values obtained when testing the different ratios of PyO with UF. PyO content influenced the properties of the boards and it is evident that PyO can be used in the manufacture of composite board.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.42-48
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• 2009

There are a number of factors affecting the continued airworthiness of composite structure. Unlike metal structure, damages made in manufacturing processes or maintenance repair procedures need to be considered. The different levels of degradation and damage, which may occur, must be considered for structural substantiation of static strength, stiffness, flutter, and damage tolerance. This can start with an evaluation of environmental effects for the particular composite material. Matrix-dominated composite properties, such as compressive strength, are most sensitive to moisture absorption and temperatures. Static strength substantiation includes the smaller damages that will not be detected in production or maintenance inspection while damage tolerance addresses larger damages that need to be repaired once discovered. In this paper, we intend to list the airworthiness regulations and advisory circular that are deemed closely related to the certification of composite airplanes.

• Journal of Korea Game Society
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• v.9 no.5
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• pp.63-72
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• 2009

I-phone presented a new mobile control type by the introducing motion recognition sensor and that influenced on game application development so that led a lot of games using kinds of sensors. In this paper, we divided the game enjoyment into 5 factors for the embodiment of the sensor's influence direction on the enjoyment. We experimented two game, which have same content, different devices in using motion recognition sensor or not for clarifying the distinction between devices. As a experiment source game, we used Cooking Mama, as a experimental device, we used I-pod touch and NDS. This experiment shows a motion recognition sensor control's enjoyment is far superior to touch sensor. This sensor got high marks on every fun factors, stimulus, absorption, empathy, accomplishment and variation. Especially, stimulus and empathy showed great differences. In this case, we found the fact that extended communication between the gamer and the device can be fun.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.136-142
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• 2015

In the paper, a design method of knee and pelvis joint in the biped robot is proposed for shock absorption and gravity compensation. Similarly to the human's body, the knee joints of the biped robot support most body weight and get a shock from the landing motion of the foot on the floor. The torque of joint motor is also increased sharply to keep the balance of the robot. Knee and pelvis joints with the spring are designed to compensate the gravity force and reduce the contact shock of the robot. To verify the efficiency of the proposed design method, we develope a biped robot with the joint mechanism using springs. At first, we experiment with the developed robot on the static motions such as the bent-knee posture both without load and with load on the flat ground, and the balance posture on the incline plane. The current of knee joint is measured to analyze the impact force and energy consumption of the joint motors. Also, we observe the motor current of knee and pelvis joints for the walking motion of the biped robot. The current responses of joint motors show that the proposed method has an effect on shock reduction and gravity compensation, and improve the energy efficiency of walking motions for the biped robot.

• Fashion & Textile Research Journal
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• v.18 no.1
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• pp.120-129
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• 2016

This study aimed to develop an optimal sizing system and a draping pattern for hip protector based on an analysis of anthropometric characteristics of Korean older women. A hip protector is a specialized form of pants or underwear containing pads along the outside of each hip. The 3D body scan data of Korean older women were analyzed to identify their anthropometric characteristics and a four-size system with 93% of population accommodation was developed by clustering analysis based on key dimensions derived from factor analysis. The sizing system consists of small/short, large/short, small/tall, and large/tall. A 3D physical model and hip pads were fabricated; then, a hip protector was draped on the 3D model and hip pads. The sizing system of hip protector was analyzed in terms of size and shape and a draping pattern was compared on back center, back side, front side, front center and pad. Lastly, the pattern deformation and clothing pressure were analyzed using the virtual clothing system CLO. Virtual system have disadvantage of not to suggest the objective value. In the future research the wearing comfort and impact absorption of the hip protector needs to be tested and then a hip protector design will be finalized by considering the hip protector's size, material, comfort testing results, aesthetic appeal, protection effectiveness, and practical utility of everyday use.