• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.23-31
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• 2018

Recently, there was an collision accident of vehicle-concrete median barrier and unfortunately, passengers were killed by exceeded capacity of concrete median. Therefore, improving the capacity of concrete median barrier is need to reduce damage. Accordingly, in this study, appropriate collision model verified by using the FE analysis program LS-Dyna and recommend a concrete median barrier section. The improvement parameters such as wire mesh diameter, steel plate, rubber pad were selected for improved capacity of the median barrier. Finally, section of concrete median barrier improved wire mesh diameter decreased volume loss, section of concrete median barrier improved rubber pad accepted impact loading and increased elastic area.

• Journal of the Korean Geotechnical Society
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• v.27 no.8
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• pp.5-16
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• 2011

The objective of this paper is to assess the potential use of the resilient force of the ground obtained from an accelerometer and to propose a new compaction control process. Several comprehensive field experimental programs were conducted to analyze the correlation of compaction results obtained from an accelerometer and conventional test methods (e.g. the plate load test and field density test). This study focused on comparing the compaction results obtained from an accelerometer with conventional test results statistically. Based on the statistical analysis results, impact and resilient force measured from an accelerometer, mounted on the drum of a roller are very useful factors for continuous compaction control. A new compaction criteria determination process using an accelerometer is also proposed in this study.

• Korean Journal of Cleft Lip And Palate
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• v.15 no.2
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• pp.61-68
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• 2012

Cleft lip and palate is the most common congenital facial malformation and has a significant developmental, physical, and psychological impact on those with the deformity and their families. When treating the patients with unilateral cleft lip, many surgeons adopt the rotation advancement flap method originally developed by Millard, or the triangular flap technique developed by Tennison, Randall or the modifications of these techniques. Among these, Millard's rotation advancement flap method has its advantage in designing the flap using the patient's anatomic landmarks. For performing this rotation advancement technique, skillful operation is needed to obtain esthetically satisfactory results. Vomer flap sometimes is used to repair anterior hard palate in complete cleft lip and palate patients. Vomerine tissue is readily available in the vicinity of the palatal defect and elevation of the vomerine flap is relatively simple procedure. In this article, we will introduce the comprehensive vomer flap technique conjunction with primary lip closure and review the comparative studies of the outcome of simultaneous repair of cleft lip and cleft hard palate with Millard's rotation advancement method and vomer flap.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.46-51
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• 2016

The TMCP steel has expanded in the marine structure during manufacturing process because of its excellent weld-ability and impact toughness. In the case of merchant ships, coverage of TMCP steel has been used widely on over DH36 Classifications material. The line heating process is applied to the outer surface of the steel plate for the shipbuilding. In this study, We compared between TMCP and normalizing steel for shipbuilding by analyzing some basic data through performing the natural cooling after the line heating. The experimental results show the angular misalignment changes in line heating. Heated surface of normalizing steel material expanded to $-0.3^{\circ}$ and reduced to $+0.2^{\circ}$ after cooling. And during cooling at $194^{\circ}C$ for 1,500 seconds, Angular Misalignment began from - direction to + direction, passed the critical point to the default at 2,200 seconds and did not take place any more at $103^{\circ}C$ after the 2,700 seconds. Angular Misalignment results of TMCP steels and Normalizing steel material show same angular misalignment lasted 1,200 seconds, TMCP steel has given more expansion and contraction angle which is $0.2^{\circ}$ than that of the Normalizing steel. Length difference between expansion and contraction is about 0.3 mm.

• Journal of the Korean Wood Science and Technology
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• v.27 no.3
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• pp.1-6
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• 1999

European spruce and maple were to be estimated as raw material of violin family instruments with linear modal analysis to provide the information data for the design of their bodies. Wood specimens cut in different direction were excited by impact hammer to measure the resonant frequency with typical vibrational modes. In spite of lower density than maple, European spruce showed the excellent acoustical properties with higher resonant frequency. And edge-grained spruce had more even frequencies than flat-grained ones to be more acceptable as front plate of violin. Resonant frequency was positively correlated with wood density of each specimen and the coefficients of edge-grained specimens were higher than those of flat-grained specimens of both wood species.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.119-128
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• 2006

This study was performed to see ground reaction force with different soccer studs with twelve players in Human Performance Laboratory(University of Calgary). Running speed was $4.0{\pm}0.2m/sec$ in straight running as well as vcut running. By using four different kinds of shoes; three different pairs of soccer shoes and one pair of jogging shoes, I reached a conclusion as following. In case of right and left ground reaction force, on the assumption that the positive magnitude of power is inversion and the negative is eversion, vcut running did not occur any inversion, which in the aspect of kinetic mechanics, thought to be decelerating movement. Because when eversion happens, it arises component force of power on heading direction about 8.6 times more than in the movement of straight running. In case of front and rear ground reaction, on the assumption that the positive magnitude of power is suspension power and the negative is propulsion, vcut movement is thought to be decelerating movement in the aspect of kinetic mechanics. Because on heading direction, this movement occurs component force of power about 1.8 times more suspension and 2.2 more propulsion than in the straight running movement. In case of vertical ground reaction, on the assumption that the first peak is the magnitude of power in impact and the second peak is the magnitude of power in active, we judged that the straight running movement performed more efficiently than the vcut movement in the aspect of kinetic mechanics. On the next study, I suppose that vcut running would make up an interesting subject in the aspect of improving kinetic performance ability.

• Journal of the Ergonomics Society of Korea
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• v.25 no.4
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• pp.115-119
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• 2006

To investigate the effects of independent suspension technology(IST) of hiking boot on the stability and load of foot, eight participants performed medial and lateral drop landing from 33.4cm height and 85cm distance to uneven surface while wearing normal & IST hiking boots. For the stability of foot during the drop landing, the balance angle & suspension angle and rearfoot angle was analyzed using high-speed video analysis. Also kinetic analysis using the force plate and insole pressure measurement was conducted to analyze vertical & breaking ground reaction force and pressure distribution. Not only the balance angle & suspension angle but also rearfoot angle was improved with IST boots for lateral drop landing. These results indicate the IST boots may have the suspension function which keeps the foot to be stable during landing. However the IST boots did not show any effect for medial landing. This might be related to the hardness of medial part of outsole. Therefore the softer outsole of medial part could be recommended. Furthermore the impact force & breaking force and insole pressure were reduced with IST boot. These results means that IST boot has not only cushioning effect but also good grip effect. Therefore the hiking boots applied the independent suspension function may help to reduce fatigue and prevent injury such as ankle sprain in hiking on uneven surface.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.4
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• pp.429-438
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• 2011

In this paper, experiment of thermal conductivity among thermal properties for CCS insulation material was carried out under the condition ranged from room temperature to cryogenic temperature. CCS insulation system should be sustained under cryogenic temperature($-163^{\circ}C$), and lots of investigations will be conducted how to block the heat to insulation material. CCS components which consist of various materials are especially the main interests, and how the temperature of the entire CCS along the location is should be investigated through these studies. With the experimental thermal properties, the steady state thermal analysis of the entire cargo system was conducted. When the LNG leaked through the insulation system with external impact, temperature distribution and thermal safety of secondary barrier, especially plywood and hull structure, was observed.

• PNF and Movement
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• v.17 no.3
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• pp.391-399
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• 2019

Purpose: This study investigated the three-dimensional moment values of the hip joint for subjects with artificial leg length alterations and subjects with unaltered leg lengths. Methods: Forty-two healthy adults (8 men, 34 women) participated in this study. The selected subjects were able to walk normally, had less than a 1 cm leg length discrepancy, and were instructed to wear shoes that fit their feet. The study participants performed 8 dynamic gait trails to measure the hip joint moment using a three-dimensional motion analysis system. Kinetic and dynamic three-dimensional gait analysis data were collected from infrared cameras, and a force plate was used to standardize the weight of each subject. Results: There were significant correlations between the differences in the leg length discrepancy during right extension, right flexion, right internal rotation, and left extension in hip joint moments (p<0.05). There were significant correlations between the differences in shoe conditions during left extension, right flexion, right extension, and right internal rotation in the hip moments (p<0.05). Conclusion: This study suggests that a leg length discrepancy can affect hip joint moment, which may further exacerbate musculoskeletal disorders, such as osteoarthritis in lower extremity joints. Therefore, further studies should be conducted to verify the impact of clinical interventions on differences in hip joint moment values to correct leg length discrepancies and prevent osteoarthritis in lower extremity joints.

• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.503-509
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• 2014

In this study, a new concept perforated breakwater is proposed, which is having resonant channels. In the channel, perforated plate is installed for dissipating wave energy induced by flow separations. The breakwater has two advantages compared with conventional perforated breakwater having wave chamber with slotted walls. One is easy to control the target wave condition for dissipating wave energy, and the other is having the high structural safety because the structural members are not exposed to impact waves, directly. To evaluate wave reflection characteristics of the proposed breakwater, numerical experiment was carried out by using Galerkin's finite element model based on the linear potential theory. The results indicated that considerable energy dissipation occurs near the resonant period of channel, and wave reflection characteristics are affected by channel shape, location and opening ratio.