• Structural Engineering and Mechanics
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• v.34 no.2
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• pp.143-157
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• 2010

This paper presents theoretical solutions for the three-dimensional (3D) stress field in an infinite isotropic elastic plate containing a through-the-thickness circular hole subjected to far-field in-plane loads by using Kane and Mindlin's assumption. The dangerous position, where the premature fracture or failure of the plate will take place, the expressions of the tangential stress at the surface of the hole and the out-of-plane stress constraint factor are found in a concise, explicit form. Based on the present theoretical solutions, a comprehensive analysis is performed on the deviated degree of the in-plane stresses from the related plane stress solutions, stress concentration and out-of-plane constraint, and the emphasis has been placed on the effects of the plate thickness, Poisson's ratio and the far-field in-plane loads on the stress field. The analytical solution shows that the effects of the plate thickness and Poisson's ratio on the deviation of the 3D in-plane stress components is obvious and could not be ignored, although their effects on distributions of the in-plane stress components are slight, and that the effect of the far-field in-plane loads is just on the contrary of that of the above two. When only the shear stress is loaded at far field, the stress concentration factor reach its peak value about 8.9% higher than that of the plane stress solutions, and the out-of-plane stress constraint factor can reach 1 at the surface of the hole and is the biggest among all cases considered.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.3
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• pp.7-13
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• 2007

In the optical module for optical communications, the flip chip bonding is used fer the precise alignment of the optical fiber and optical device. In flip chip bonding, the optical device is aligned and welded while observing the alignment mark of substrate and chip by using flip chip bonder in order to bond the optical device at the exact position. In this research, optical passive alignment method of photodiode(PD) flip chip bonding is suggested for low cost optical subassembly. By using the visible He-Ne laser (633nm wavelength), photodiode is easily aligned with emitting spot on the optical fiber with the help of stereoscopic alignment system. We compensated wavelength dependent deviation about 4m to find out real alignment position of 1550nm input laser by ray tracing. The maximum optical coupling efficiency between the optical fiber and photodiode was about 23.3%.

• Physical Therapy Rehabilitation Science
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• v.5 no.1
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• pp.34-39
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• 2016

Objective: Hip abductors play a role in providing stability and movement to the lower limbs. The purpose of this study was to examine the effects of hip abductor fatigue on static balance and gait in the general population. Design: One group pre-test post-test design. Methods: Thirteen university students in their twenties volunteered for the study and had underwent a functional assessment. To induce fatigue, the subjects were instructed to raise their dominant lower extremity up against a load of 50% of 1 repetition maximum while producing hip abduction in a side-lying position. Subjects were instructed to maintain an abduction speed of 30 repetitions per minute to induce fatigue. Muscle fatigue was considered to be established when subjects were unable to perform hip abduction three consecutive times along with the metronome. A post-test of balance and gait was performed immediately in order to prevent fatigue recovery. The center of pressure (COP) distance area was measured using the Zebris FDM-S Multifunction Force measuring plate. Gait performance was analyzed using the GAITRite. Results: The COP distance was increased after fatigue was induced. There was a significant increase in the standard deviation of the medio-lateral and antero-posteror distance (p<0.05). Although there was no significant difference in gait parameters, there was a significant decrease in single support time after fatigue was induced (p<0.05). Conclusions: There was an increase in static balance instability and a significant decrease in single support time during gait due to hip abductor muscle fatigue.

• Journal of Sasang Constitutional Medicine
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• v.28 no.2
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• pp.123-131
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• 2016

Objectives We observed what effects of Paced Breathing(PB) in specific respiration rate have on heart rate variability (HRV) according to Sasang Constitution.Methods HRV of 72 healthy participants in sitting position was recorded while they carried out usual breathing, 0.2Hz, 0.1Hz, and 0.05Hz PB each 5 minutes in consecutive order. Five minute of relaxation was permitted between each breathing. Finally, HRV indices were statictically analyzed of 32 participants (SOEUM: 11, SOYANG: 10, TAEEUM: 11) after data out of accord with respiration rate or outliers were excluded.Results and Conclusions According to respiration rates, there was no statistical significance of HRV among Sasang Constitution. Regardless of Sasang Constituion, 0.2Hz PB increased mean heart rate and decreased natural logarithmic low frequency(lnLF) oscillation of HRV without the change of natural logarithmic high frequency(lnHF), while 0.1Hz PB increased lnLF and standard deviation of N-N interval(SDNN), and slightly decreased lnHF without the change of mean heart rate. 0.05 Hz PB also showed the same effect as 0.1Hz PB, but was impracticable.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.4
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• pp.413-423
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• 2001

Low back disorders (LBDs) are one of the most common and costly work-related musculoskeletal disorders. One of the major possible risk factors of LBDs is to work with static and awkward trunk postures, especially in a complex trunk posture involving flexion, twisting and lateral bending simultaneously. This study is to examine the effect of complex trunk postures on the postural stresses using a psychophysical method. Twelve healthy male students participated in an experiment, in which 29 different trunk postures were evaluated using the magnitude estimation method. The results showed that subjective discomfort significantly increased as the levels of trunk flexion, lateral bending and rotation increased. Significant interaction effects were found between rotation and lateral bending or flexion when the severe lateral bending or rotation were assumed, indicating that simultaneous occurrence of trunk flexion, lateral bending and rotation increases discomfort ratings synergistically. A postural workload evaluation scheme of trunk postures was proposed based on the angular deviation levels from the neutral position. Each trunk posture was assigned numerical stress index depending upon its discomfort rating, which was defined as the ratio of discomfort of a posture to that of its neutral posture. Four qualitative action categories for the stress index were also provided in order to enable practitioners to apply corrective actions appropriately. The proposed scheme is expected to be applied to several field areas for evaluating trunk postural stresses.

• Korean Journal of Adult Nursing
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• v.16 no.3
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• pp.378-387
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• 2004

Purpose: The study was undertaken to examine the degree of nurse's suffering experience and to identify the influencing factors on nurses' suffering experience in Korea. Method: Data were collected using a questionnaire for 271 nurses working at 5 general hospitals in Daegu and Kyung-book province from Sep. 1, to Sep. 30, 2003. The questionnaire consists of 54 items, general characteristics(10) and nurse's suffering experience(44). All surveys were sorted and studied by frequency analysis, mean score, standard deviation, range, independent t-test, one way ANOVA, Pearson's correlation coefficient and Multiple regression. Result: The findings of this survey indicate 1) The degree of suffering experienced by nurses caring for terminal cancer patients was 2.96; 2) Demographic variables affecting the degree of nurses' suffering experience were age(F=5.62, p=.000), marital status(F=20.53, p=.000), religion(F=5.44, p=.020), career of clinical experience(F=6.96, p=.000), and feelings of end-life care(F=3.11, p=.016); 3) There were slight correlation between the subitem of nurse's suffering experience and general characteristics of subjects. For 'expanding self consciousness', age, career duration, and position; for 'forming empathy with family', age and career duration ; for 'spiritual sublimation', age, and career duration were affected variables. 4) As a result of the multiple regression analysis for predictable variables affecting nurses' suffering, it was found that 'career of clinical experience' was most significant(F=23.100, p=.000). The explanatory power of this regression formula was 17.6%. Conclusion: This study can provide the basic data useful towards improvement of nursing services for terminal cancer patients and the health of the nurse.

• Physical Therapy Korea
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• v.28 no.1
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• pp.65-71
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• 2021

Background: The hamstring is a muscle that crosses two joints, that is the hip and knee, and its flexibility is an important indicator of physical health in its role in many activities of daily living such as sitting, walking, and running. Limited range of motion (ROM) due to hamstring tightness is strongly related to back pain and malfunction of the hip joint. High-frequency diathermy (HFD) therapy is known to be effective in relaxing the muscle and increasing ROM. Objects: To investigate the effects of HFD on active knee extension ROM and hamstring tone and stiffness in participants with hamstring tightness. Methods: Twenty-four participants with hamstring tightness were recruited, and the operational definition of hamstring tightness in this study was active knee extension ROM of below 160° at 90° hip flexion in the supine position. HFD was applied to the hamstring for 15 minutes using the WINBACK device. All participants were examined before and after the intervention, and the results were analyzed using a paired t-test. The outcome measures included knee extension ROM, the viscoelastic property of the hamstring, and peak torque for passive knee extension. Results: The active knee extension ROM significantly increased from 138.8° ± 9.9° (mean ± standard deviation) to 143.9° ± 10.4° after the intervention (p < 0.05), while viscoelastic property of the hamstring significantly decreased (p < 0.05). Also, the peak torque for knee extension significantly decreased (p < 0.05). Conclusion: Application of HFD for 15 minutes to tight hamstrings immediately improves the active ROM and reduces the tone, stiffness, and elasticity of the muscle. However, further experiments are required to examine the long-term effects of HFD on hamstring tightness including pain reduction, postural improvement around the pelvis and lower extremities, and enhanced functional movement.

• Korean Journal of Cleft Lip And Palate
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• v.15 no.1
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• pp.21-28
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• 2012

Unilateral cleft lip is not a simple and independent problem in all aspects. nasal deformity results from the cleft lip, maxillary hypoplasia, and abnormal muscular pull on the nasal structures, including abnormal muscular tension on the alar base and abnormal position of the orbicularis oris muscle. Its gross and histopathologic characteristics include widening of the alar base, a midline deviation of the columella and septum to the noncleft side, dorsal displacement of the dome, lateral rotation of medial crura, buckling of the alar cartilage, and underdevelopment of the pyriform aperture. Since Dr. Millard first presented his method for repair of the unilateral cleft lip and nasal deformity in 1955, no other technique has gained as much popularity as the rotation-advancement principle. Principles established more than 50 years ago and techniques are evolving continuously. Unlike earlier procedures, this repair gives the surgeon the opportunity to manipulate the individual cleft elements through various modifications while maintaining Millard's original surgical and anatomical goals. Although this strategy is applied worldwide, successful execution is variable and highly operator dependent. Millard and many other surgeons have made technical variations to adjust the procedure to each specific patient, to address some of its faults, and to gain new advantages. We will review the Mulliken's modifications that Dr. Millard made to his original rotation-advancement principle and inform cases applied modifying the rotation-advancement principle.

• Journal of The Korean Astronomical Society
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• v.48 no.4
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• pp.213-228
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• 2015

The Horizon Run 4 is a cosmological N-body simulation designed for the study of coupled evolution between galaxies and large-scale structures of the Universe, and for the test of galaxy formation models. Using 6300³ gravitating particles in a cubic box of L_box = 3150 h⁻¹Mpc, we build a dense forest of halo merger trees to trace the halo merger history with a halo mass resolution scale down to M_s = 2.7 × 10¹¹h⁻¹M_⊙. We build a set of particle and halo data, which can serve as testbeds for comparison of cosmological models and gravitational theories with observations. We find that the FoF halo mass function shows a substantial deviation from the universal form with tangible redshift evolution of amplitude and shape. At higher redshifts, the amplitude of the mass function is lower, and the functional form is shifted toward larger values of ln(1/σ). We also find that the baryonic acoustic oscillation feature in the two-point correlation function of mock galaxies becomes broader with a peak position moving to smaller scales and the peak amplitude decreasing for increasing directional cosine μ compared to the linear predictions. From the halo merger trees built from halo data at 75 redshifts, we measure the half-mass epoch of halos and find that less massive halos tend to reach half of their current mass at higher redshifts. Simulation outputs including snapshot data, past lightcone space data, and halo merger data are available at http://sdss.kias.re.kr/astro/Horizon-Run4.

• Physical Therapy Korea
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• v.11 no.4
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• pp.7-17
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• 2004

Individuals who propel wheelchairs have a high prevalence of upper extremity injuries (i.e., carpal tunnel syndrome, elbow/shoulder tendonitis, impingement syndrome). Musculoskeletal injuries can result from overuse or incorrect use of manual wheelchairs, and can hinder rehabilitation efforts. To better understand the mechanisms of upper extremity injuries, this study investigates the motion of the wrist during wheelchair propulsion. This study also examines changes in the variables that occur with fatiguing wheelchair propulsion to determine how the time parameters of wheelchair propulsion and the state of fatigue influence the risk of injury. A two dimensional (2-D) analysis of wrist movement during the wheelchair stroke was performed. Twenty subjects propelled a wheelchair handrim on a motor-driven treadmill at two different velocities (50, 70 m/min). The results of this study were as follows; The difference in time parameters of wheelchair propulsion (cadence, cycle time, push time, recovery time, and PSP ratio) at two different velocities was statistically significant. The wrist kinematic characteristics had statistically significant differences at two different velocities, but wrist radial deviation and elbow flexion/extension had no statistically significant differences. There were statistically significant differences in relation to fatigue in the time parameter of wheelchair propulsion (70 m/min) between initial 1 minute and final 1 minute. The wrist kinematic characteristics between the initial 1 minute and final 1 minute in relation to fatigue had statistically significant differences but the wrist flexion-extension (50 m/min) had no statistically significant differences. According to the results, the risk of musculoskeletal injuries is increased by fatigue from wheelchair propulsion. To prevent musculoskeletal injuries, wheelchair users should train in a muscle endurance program and consider wearing a splinting/grove. Moreover, wheelchair users need education on propulsion posture, suitable joint position, and proper recovery patterns of propulsion.