• Korean Journal of Health Education and Promotion
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• v.21 no.3
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• pp.53-66
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• 2004

Purpose: To compare differences in BMI, body weight perception and satisfaction, and eating behavior by gender among middle school students. Methods: From 19 middle schools in W city four classes in two middle schools were selected by cluster sampling with multi-stage sampling. A structured questionnaire was answered by 143 adolescents. Results: Differences in BMI between boys and girls were significant (x$^2$=13.15, p=.00l). Boys reported higher ideal body weight than girls (t=6.33, p<.000l), and discrepancy between ideal body weight and body weight perception in girls was significantly greater than in boys(t=-5.0l, p<.0001). There was no significant gender difference in body weight perception but more boys were satisfied with their body weight(t=-4.48, p<.0001). Comparison of eating behavior showed that girls reported high scores in disinhibition (t=-2.29, p<.05) and hunger (t=-2.81, p<.01), while boys reported higher scores in cognitive restraints (t=3.22, p<.01). Conclusion: Interventions to help girls improve body image and satisfaction with body image are crucial. In order to establish proper diet habits and balanced nutritional status for adolescents, educational interventions should address characteristics of eating behaviors.

• Computers and Concrete
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• v.25 no.5
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• pp.411-425
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• 2020

In this paper, the shell material has been taken as functionally graded material and their material quantity is located by the exponential volume fraction law. Moreover, the impact of ring supports around the shell circumference has been examined for their various positions along the shell axial length. These rings support restraints the radial displacement in the transverse direction. While the axial modal deformation functions have been estimated by characteristic beam functions and nature of materials used for construction of cylindrical shells. The fundamental natural frequency of cylindrical shell of parameter versus ratios of length- and height-to-radius for a wide range has been reported and investigated through the study. In addition, by increasing height-to-radius ratio resulting frequencies also increase and frequencies decrease on ratio of length-to-radius. Though the trends of frequency values of both ratios are converse to each other with three different boundary conditions. Also it is examined the position of ring supports with length-to radius ratio, height-to-radius ratio and varying the exponent of volume fraction. MATLAB software package has been utilized for extracting shell frequency spectra. The obtained results are confirmed by comparing with available literature.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.280-283
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• 1997

Human cervical spine has to protect the neural components and vascular structures. Also, it must have the flexibility afforded by an extensive range of motion to integrate the head with the body and environment. Because of these two-sided features, human cervical spine has very complicated shapes and their injury mechanisms are not fully understood yet. We have developed analytical model of human CS by using the finite element method. The model has been verified with in vivo and in vitro experimental results. From the qualitative analysis of simulation results, we were able to explain some of the fundamental mechanisms of neck pain. Further more, this FE model of human CS can be used as an analytical tool or biomechanical design of the clinical device and safety restraints.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.2
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• pp.119-126
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• 2003

The shoulder is a complex joint and, by virtue of having a large range of motion, is inherently unstable, relying on the surrounding soft tissue structures for stability. The bony joint consists of the glenoid, acromion, and humoral head, while the soft tissues include the glenoid labrum, the glenohumeral ligaments. and coracoacromial ligament as well as the muscles of the rotator cuff, the long head of the biceps, and the scapulothoracic muscles. Dysfunction in any one of these components can cause shoulder problems. The throwing motion involves a series of phases that stress to their limits the dynamic and static restraints of the glenohumeral and scapulothoracic joints. . Therefore, maintaining a balance of proper biomechanical forces is essential to avoiding shoulder injuries in throwing athletes. Over the last decade, signficant advances have been made in the study and understanding of the shoulder mechanics, and pathophysiology of injury. Additionally, advances in surgical techniques, particularly arthroscopy , have aided in the diagnosis of and the developement of less invasive surgical treatments for injuries that do not respond to nonoperative measures. In this article, we reviewed the pathophysiology of injuries , diagnostic techniques, and surgical management of shoulder injuries in throwing athletes .

• Journal of Korean Society of Steel Construction
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• v.15 no.3
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• pp.281-290
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• 2003

A series of connection tests of portal frames which were composed of cold-formed steel studs and rafters was carried out to study the moment-rotation relation, the rotational rigidity, and the yield and the ultimate moment of the connections. The main factors of the tests were the thickness, the shape of the connecting members which were made of mild steel, and the torsional restraints of the test specimens. The test results were compared with those obtained through the non-linear analysis, for verification. The secant stiffness estimated from the experimental moment-rotation curve was proposed for the rotational rigidity of semi-rigid connections, and its validity was verified in the structural frame analysis.

• Biomolecules & Therapeutics
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• v.14 no.2
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• pp.75-82
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• 2006

Synaptic plasticity, which is a long lasting change in synaptic efficacy, underlies many neural processes like learning and memory. It has long been acknowledged that new protein synthesis is essential for both the expression of synaptic plasticity and memory formation and storage. Most of the research interests in this field have focused on the events regulating transcriptional activation of gene expression from the cell body and nucleus. Considering extremely differentiated structural feature of a neuron in CNS, a neuron should meet a formidable task to overcome spatial and temporal restraints to deliver newly synthesized proteins to specific activated synapses among thousands of others, which are sometimes several millimeters away from the cell body. Recent advances in synaptic neurobiology has found that almost all the machinery required for the new protein translation are localized inside or at least in the vicinity of postsynaptic compartments. These findings led to the hypothesis that dormant mRNAs are translationally activated locally at the activated synapse, which may enable rapid and delicate control of new protein synthesis at activated synapses. In this review, we will describe the mechanism of local translational control at activated synapses focusing on the role of cytoplasmic polyadenylation of dormant mRNAs.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.2
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• pp.205-212
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• 1989

The minimum weight design for the simply supported orthogonally stiffened cylindrical shell subjected to axial compression is studied by a mathematical programming. A smeared-out method is used for the computation of buckling load in the optimization process and optimization is accomplished by a gradient projection method. Maximum eight design variables and twenty-one inequality constraints considering the buckling, stress and geometric restraints are used. The three stringer types are considered as the optimization models : (1) rectangular stringer (2) I-stringer (3) T-stringer. Two design examples are compared with those in the other studies and the results demonstrate the validity of the present study. From the calculation the design with T-stringer can be more efficient than the one with rectangular or I-stringer.

• Journal of Korean Society of Disaster and Security
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• v.7 no.1
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• pp.43-50
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• 2014

Based on the reliability theory, the risk assessment of steel beams is performed by the determination of failure probability. In the calculation, bending, shearing and combined (bending + shearing) modes are examined. The resistance and the loads on the beam are assumed to be normal distribution. To investigate the failure probability changes, total load applied at the mid span of beam is divided into 1 to 1 and 1 to 2 ratio and then these divided loads are placed on the trisected points on beam. The change of boundary conditions at beam ends are also included in the investigation. It shows that failure is governed by the combined mode for the present beams and the second order bound analysis of failure probability is not crucial. On the whole failure probability decreases with increasing end restraints at the beam ends with some exception.

• Journal of Auto-vehicle Safety Association
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• v.5 no.2
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• pp.45-50
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• 2013

The whiplash Injuries due to rear collision occur frequently. As result, in many countries, seat performance is being assessed and developed to improve head whiplash injury in rear collision of passenger car. This study compares whiplash assessment methods in each country. Using the DFSS(Design for Six Sigma) method, the correlation between influence parameters of head restraints and whiplash injury criteria is analyzed. Four control factors are used in this study. And total 11 whiplash injury criteria from NCAP(New Car Assessment Program) of Korea, Europe, China and IIHS(Insurance Institute for Highway Safety) of USA are used for output response. By the experimental design, L9 orthogonal coordinate system is configured and is tested by sled test equipment, twice. By using average assay value and ANOVA, the correlation between control factors and injury criteria has been comprehended. Optimization design of head restraint according the regional seat safety assessment was derived through the correlation.

• Journal of Welding and Joining
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• v.29 no.4
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• pp.80-84
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• 2011

In the 5xxx series Al-Mg alloy, magnesium addition can increase the strength of aluminum alloy by solid solution strengthening but it has a relatively low melting and boiling temperature. During full -penetration laser welding of the Al-Mg alloys, its low boiling point and high vapor pressure brings about the spiky humping bead on the bottom side. Under back-side shielding, the spiking of back bead can be reduced but it restraints the process flexibility. In this study, a square pulse waveform modulation was employed to stabilize keyhole and back bead surface without back-side shielding. By using an experimental design, the bead shapes were evaluated for various process parameters such as the focal position, welding velocity and waveform parameters and the smooth back bead shape could be achieved.