• Physical Therapy Korea
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• v.19 no.3
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• pp.81-90
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• 2012

The aim of the current study was to assess the effectiveness of backward gait training on the treadmill in patients with spastic diplegic cerebral palsy (CP). Twelve patients with spastic diplegic CP participated in the study. An 8-week course of backward gait training was administered to the subjects for 3 days per week. Pre-intervention and post-intervention assessments of temporal-spatial gait parameters, the symmetry of the bilateral lower extremity weight bearing, and gross motor function were analyzed using motion analysis system, force plate, and Gross Motor Function Measurement (GMFM). There were significant improvements (p<.05) in the measures of both step length and right stance phase time. Joint kinematics showed increase in right hip abduction in initial contact and terminal swing, right hip external rotation and knee flexion in mid-swing, left ankle dorsiflexion in initial contact and terminal swing (p<.05). The symmetry of the bilateral lower extremity weight bearing and GMFM also significantly increased (p<.05). These findings indicate that backward gait training using a treadmill is beneficial for patients with spastic diplegic CP.

• Composites Research
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• v.27 no.4
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• pp.141-145
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• 2014

This paper presents a structural health monitoring method using piezoelectric paint sensor designed for an impact sensor. The piezoelectric paint sensor can be flexibly deposited onto most structural surfaces in a thin form of the paint, and measure impact signals without any external device such as a power amplifier. In this study, a composite plate having four zones coated with piezoelectric paint was used for impact monitoring test. The sensitivity of the piezoelectric paint sensor was obtained by measuring the output voltages against the impact force. In addition to the sensitivity measurement, the impact position has been also estimated by comparing the output signals of the paint sensors when the impact occurs on the specimen.

• Korean Journal of Community Nutrition
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• v.1 no.2
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• pp.178-188
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• 1996

Blood pressure distribution of adolescents and its several related factors including obesity were investigated through blood pressure measuring by automated oscillometric method, anthropometry, and questionnaire. Subjects were 480 female and 480 male middle school students living in Taejon. Mean values of systolic(SBP)/diastolic(DNP) blood pressure of male and female students were 118.4$\pm$11.0/69.5$\pm$9.6 mmHg and 116.9$\pm$10.4/69.5$\pm$8.6 mmHg, respectively. Their blood pressures, particularly SBP, increased with age and showed higher value in the males than in the females. All frequency distributions of SBP and DBP, by sex and age, showed normal curves and their 50th, 90th, and 95th percentiles were presented. As obese index increased, both SBP and DBP were elevated and the prevalence of hypertension which was classified by Task Force Report(1987) increased, particularly in male students. Body weight and BMI were positively correlated with both SBP and DBP, and hight was also positively correlated with SBP or DBP. Our data inicated that blood pressure and hypertension prevalence of adolescents tended to increase and various internal and external environmental factors affected them. It was emphasized that blood pressure measurement should be done in every medical examination of adolescents and the nationwide Korean standard of blood pressure for adolescents have to be prepared. (Korean J Community Nutrition 1(2) : 178-188, 1996)

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.8 s.227
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• pp.921-928
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• 2004

Measurements of local heat/mass transfer coefficients in rotating two-pass ducts are presented. Ducts of three different aspect ratios (W/H), 0.5, 1.0 and 2.0, are employed with a fixed hydraulic diameter ($D_h$) of 26.7 nm. $90^{\circ}$-rib turbulators are attached on the leading and trailing walls symmetrically. The rib height-to-hydraulic diameter ratio ($e/D_h$) is 0.056, and the rib pitch-to-rib height ratio (p/e) is 10. The experimental conditions are the same as those of the previous part of the study. As the rib height-to-duct height ratio (e/H) increases, the core flow is more disturbed and accelerated in the midsections of ribs. Therefore, the obtained data show higher heat/mass transfer in the higher aspect ratio duct. Dean vortices also augment heat/mass transfer in the turn and in the upstream region of the second pass. However, the effect becomes less significant for the higher aspect ratio because the surface area increases in the present geometric condition. The effect of rotation produces heat/mass transfer discrepancy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.3
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• pp.502-510
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• 1997

A disturbance rejection controller using eccentricity filtering and LQ control techniques is proposed to alleviate the effecto of major roll eccentricity in multivariable cold-rolling processes. Fundamental problems in multivariable cold-rolling processes such as process time delay inherent in exit thickness measurement and non-stationary characteristics of roll eccentricity signals can be overcome by the proposed control method. The filtered instantaneous estimate of roll eccentricity may be exploited to improve instantaneous estimate of the exit thickness variation based on roll force and roll gap measurements, and a feedforward compensator is augmented as a reference for a gaugemeter thickness estimator. LQ feedback controller is combined with eccentricity filter for the attenuation of the exit thickness variation due to the entry thickness variation. The simulation results show that the roll eccentricity disturbance is significantly eliminated and other disturbances also are attenuated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.1
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• pp.14-19
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• 2016

Transmission error (TE) is the most important cause of gear noise and vibration because TEs affect the changes of the force and the speed of gears. TE is usually expressed as an angular deviation, or a linear deviation measured at the pitch point and calculated at successive positions of the pinion as it goes through the meshing cycle. Accurate measurement of TE for gear transmission will provide a reasonable basis for gear design, manufacturing processes and quality control. Therefore, in order to study the accuracy of the gear transmission, stability, TE, vibration and noise after gear micro-geometry modification, a gear transmission test rig is proposed in this paper, which is based on the existing technical conditions, by using reasonable testing methods, hardware and a signal processing method. All of the details and the experience can be taken into consideration in the next upgraded test rig.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.10 s.241
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• pp.1092-1100
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• 2005

In the present study, characteristics of steady state laminar flows of a straight duct connected to a 180$^{o}$ curved duct were examined in the entrance region through experimental and numerical analyses. For the analysis, the governing equations of laminar flows in the Cartesian coordinate system were applied. Flow characteristics such as velocity profiles and secondary flows were investigated numerically and experimentally in a square cross-sectional straight duct by the PIV system and a CFD code(STAR CD). For the PIV measurement, smoke particles produced from mosquito coils. The experimental data were obtained at 9 points dividing the test sections by 400 3m. Experimental and numerical results can be summarized as follows. 1) Reynolds number, Re was increased, dimensionless velocity profiles at the outer wall were increased due to the effect of the centrifugal force and secondary flows. 2) The intensity of a secondary flow became stronger at the inner wall rather than the outer wall regardless of Reynolds number. Especially, fluid dynamic phenomenon called conner impact were observed at dimensionless axial position, x/D$_{h}$=50.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.2
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• pp.152-161
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• 2013

This paper presents a control effectiveness analysis of the hawkmoth Manduca sexta. A multibody dynamic model of the insect that considers the time-varying inertia of two flapping wings is established, based on measurement data from the real hawkmoth. A six-degree-of-freedom (6-DOF) multibody flight dynamics simulation environment is used to analyze the effectiveness of the control variables defined in a wing kinematics function. The aerodynamics from complex wing flapping motions is estimated by a blade element approach, including translational and rotational force coefficients derived from relevant experimental studies. Control characteristics of flight dynamics with respect to the changes of three angular degrees of freedom (stroke positional, feathering, and deviation angle) of the wing kinematics are investigated. Results show that the symmetric (asymmetric) wing kinematics change of each wing only affects the longitudinal (lateral) flight forces and moments, which implies that the longitudinal and lateral flight controls are decoupled. However, there are coupling effects within each plane of motion. In the longitudinal plane, pitch and forward/backward motion controls are coupled; in the lateral plane, roll and side-translation motion controls are coupled.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1228-1231
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• 2005

This paper reports about the development of scanning probe microscopy (SPM) tip with multi-walled carbon nanotube (MWNT). For making a carbon nanotube (CNT) modified tips, AC electric field which causes the dielectrophoresis was used for alignment and deposition of CNTs to the metal coated SPM tip. By dropping the MWNT solution and applying an electric field between an SPM tip and an electrode, MWNTs which were dispersed into a diluted solution were directly assembled onto the apex of the SPM tips due to the attraction by the dielectrophoretic force. In this paper, we investigate experimental conditions about the alignment of the CNT to tip axis according to the change of the angle between a tip and an electrode. Experimental results are presented, and then fabricated CNT tips are showed and measurement results for 15nm gold particles are compared with that of the conventional silicon tip.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.1 s.190
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• pp.118-125
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• 2007

In this study, we analyzed the plantar shear stress and normal pressure in lateral heel diabetic foot patients during walking by using in-shoe local shear stress and plantar pressure measurement systems. The shear force transducer based on the magnetic-resistive principle, was a rigid 3-layer circular disc. Shear transducers were mounted on the locations of four metatarsal heads and heel in the insole. Twelve normal subjects and three diabetic foot patients with diabetic neuropathy in the lateral heel participated in this study. The center of pressure in lateral heel diabetic foot patients moved more medially and directed toward the first, medial to the second metatarsal heads, and the hallux during late stance, making pressure at the medial heel and the second metatarsal head significantly larger than in the normal. Shear stress at the heel changed significantly in early stance and the magnitude of shear stresses in each metatarsal head also changed. Further studies would be very helpful to design foot orthoses in patients with diabetic neuropathy or other diseases.