• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.4
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• pp.1-8
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• 2010

In the aerospace field, the study on a morphing-wing is in progress to improve flight performance and perform multi flight mission. There are many concepts of morphing-wing such as camber-change, wing-twist, variable-span, and so on. In this study, the aerodynamic characteristics and flight control of an air vehicle with a variable-span morphing wing (VSMW) have been investigated. VSMW with symmetric span control(SSC) can increase cruising range of aircraft by reducing drag in various flight condition. VSMW with anti-symmetric span control(ASSC) can be used in the roll control of an aircraft. The flight control about pure rolling dynamic system and full dynamic system have been performed about the cruise missile.

• Journal of Aerospace System Engineering
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• v.10 no.4
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• pp.11-16
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• 2016

In this paper, an experimental study on the aerodynamic characteristics of a variable span wing flying inside a channel guideway is accomplished using wind tunnel testing. A variable span wing with a NACA 0012 airfoil section was fabricated and actuated using a linear servo motor. The aerodynamic effects of 1) wing aspect ratio, 2) ground effect, and 3) the gap between the wingtip and the wing fence were investigated. It was found that both ground effect and wing fence gap increased lift. Also, the wing fence gap does not significantly affect drag. Therefore, it was found that a variable span mechanism can be used as an effective high lift device when flap use is limited.

• Ocean Systems Engineering
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• v.6 no.4
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• pp.363-375
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• 2016

Large numbers of submarine pipelines are laid as the world now is attaching great importance to offshore oil exploitation. Free spanning of submarine pipelines may be caused by seabed unevenness, change of topology, artificial supports, etc. By combining Iwan's wake oscillator model with the differential equation which describes the vibration behavior of free-span submarine pipelines, the pipe-fluid coupling equation is developed and solved in order to study the effect of both internal and external fluid on the vibration behavior of free-span submarine pipelines. Through generalized integral transform technique (GITT), the governing equation describing the transverse displacement is transformed into a system of second-order ordinary differential equations (ODEs) in temporal variable, eliminating the spatial variable. The MATHEMATICA built-in function NDSolve is then used to numerically solve the transformed ODE system. The good convergence of the eigenfunction expansions proved that this method is applicable for predicting the dynamic response of free-span pipelines subjected to both internal flow and external current.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.530-537
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• 2006

Recently, the railroad route plan is trying to minimize the damage of the local resident which is caused by railroad construction. For this reason, reducing the banking height of soil roadbed, lowering the bridge girder height of a solid intersection and a part of cross river, the through bridge type which can achieve a required span length must apply. The representative through bridges of railroad are arch bridges, truss bridges and plate girder bridges, the through plate girder bridge of variable section can apply that the span length of these bridges is about $30{\sim}50m$, namely, middle span length bridge types, and that can satisfy structural capacity and beauty of railroad at the same time. This paper introduces plan and design process of the Su-eo cheon bridge applied by a through plate girder bridge type of the Jinju-Gwangyang double track 6th construction ordered at Korea Rail network Authority in 2005.

• Journal of Aerospace System Engineering
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• v.10 no.3
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• pp.39-43
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• 2016

In this paper, a wind-tunnel test is accomplished to investigate the roll characteristics of a variable-span wing flying inside a channel. The factors that affect the roll characteristics of the wing were identified by analyzing the measured data; accordingly, when the wing is flying without both the ground and sidewall effects, the asymmetric wing extension causes the roll moment. Both the ground and the sidewall can increase the roll moment, but when the wing is affected by both the ground and the sidewall, the roll moment does not increase as much as the case where the wing is only affected by the ground. Also, the aerodynamic characteristics of the flying wing inside a channel are the nonlinear function of the wing height and the gap between the wingtip and the sidewall, both of which should be considered in a study of the stability and the flight control of the wing-in-ground effect of the vehicle flying inside a channel.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.04a
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• pp.139-146
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• 1997

The main purpose of this paper is to investigate the near-optimal parameters of continuous beam subject to a moving load. The computer-aided optimization technique is used to obtain the near-optimal parameters. The computer program is developed to obtain the natural frequency parameters and the forced vibration responses to a transit point load for the continuous beam with variable support spacing, mass and stiffness. The optimization function to describe the design efficiency is defined as a linear combination of four dimensionless span characteristics: the maximum dynamic stress; the stress difference between span segments; the rms deflection under the transit point load; and the total span mass. Studies of three span beams show that the beam with near-optimal parameters can improve design efficiency by 12 to 24 percent when compared to a reference configuration beams of the same total span length.

• Journal of Families and Better Life
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• v.28 no.6
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• pp.47-57
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• 2010

This study examines the effects of parental variable(parental support and supervision), temperament(activity level, attention span/persistence, and emotionality) and the internal locus of control on self-regulation of children. Data were collected from 455 5th and 6th graders and analyzed with Pearson's correlations and pathway analysis. The results were as follows : Children's temperament, internal locus of control and parental variable directly affected children's self-regulation. Parental variables mediated between children's temperament and internal locus of control and self-regulation. Internal locus of control mediated between children's temperament and self-regulation: in addition, the most important variable predicting children's self-regulation was children's attention span/persistence temperament.

• The Journal of Korean Physical Therapy
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• v.1 no.1
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• pp.27-45
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• 1989

This study aims at helping cerebrally palsied children to overcome and minimize their sufferings, inducing them to perform ordinary activities of daily living for themselves by coducting ADL Tests which are fundamental activities in daily life and presenting treatment plan for their overall rehabilitation and basic data for achieving the training objective. For that purpose, 173 cerebrally palsied children were selected and given ADL performance Tests from Dec. 1987 to Oct. 1988 and the following results were obtained. 1. Correlation coefficients for each ADL category indicated significant statistical value at .01 level. 2. Correlation coefficient between school-year variable and ADL category variable was significant at .01 level. 3. Correlation between age variable and ADL variable category proved significant at .01 level as well. 4. Correlation coefficients between each category in terms of functional state of extremities were significant at .01 level. 5. The difference in ADL achievements between each category by school year were as follows ; 1) In the category of meeting nature's tall, the age span of more than 4 school years showed statistical significance. 2) In the category of putting off and on clothing, the age span of 3 school years indicated statistical significance. 3) In taking meals statistical significance was found in the age span of 4 school years. 4) In finger movements the age span of more the 4 school years indicated statistical significance. 5) In walking activities statistical significance was noticed in the age span of 2 or 3 school years. Besides, in category by school year, and exceptional case was noticed that the 6th graders were lower than the 5th graders in self-reliance rate. 6. the difference in ADL achievements by type of palsy, children of triplegia were the lowest, while those of monoplegia were the highest. 7. The difference in ADL achievements by kind of palsy, patients of athetosis showed lower rate of self-reliance than those of spasticity, and particularly the latter showed a high rate of self-reliance in taking meals$(83.5\%)$. The former were relatively low in self-reliance and lowerst in meeting nature's call $(59.8\%)$.

• The Korean Journal of Community Living Science
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• v.25 no.3
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• pp.303-319
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• 2014

This study considers structural equation model and examines the-relationships between various model variables to identify the causal relationships of between the attention span temperament, affectionate rearing attitudes of mothers, and family support (individual external variables) to children's behavioral problems though self-reliance, psychological variable. According to the results, the attention span temperament had significant direct, indirect, and total effects on the externalization of behavioral problems, but affectionate rearing attitudes and family support had only significant indirect effects. Self-resilience had a significant direct effect. These results can be used as basic data to prevent behavioral problems of children and increase their self-resilience.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.781-787
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• 2004

Where the track is continuously welded over a bridge, the longitudinal force is interacted between the track and the sub-structure. Due to this respect, the expansion joint is used to decrease this force. But the expansion joint has several problems related to passenger comfort and maintenance etc. In this study, it is analysed about how the stability of the track is affected as the span length becomes longer in case of 2-span continuos bridge. It is found that there is no problem of an stability unless the span length is longer than 90m when the elastic shoe is used. And several parametric studies were also implemented.