• Korean Journal of Applied Biomechanics
• /
• v.18 no.4
• /
• pp.135-142
• /
• 2008

The primary innovation in the new footwear is a heel lift of $20^{\circ}$ which is proposed to improve posture and balance as well as increase shock absorption. The purpose of this research was to compare the movement, forces and muscle activity between the new shoes and standard athletic footwear during standing and walking. Nine healthy subjects participated in this study. Data were collected at two times: 1) when the subjects first wore the new walking shoes and 2) after the subjects wore the shoes for 6 hours a day for two weeks. 1. During standing. the movement of the center of pressure is increased approximately 60% when wearing the new walking shoes compared to a control shoe. 2. During walking. the ankle is approximately $14^{\circ}$ more dorsiflexed during landing due to the 200heel lift in the new walking shoes. The knee compensates slightly by flexing approximately $2^{\circ}$ more. 3. As a result of the changes in the walking movement, the ground reaction forces are applied more quickly, although the peak magnitudes do rut change. 4. The resultant joint moments at the ankle and knee joints decrease from 21-60% with the largest reductions occurring during landing. In conclusion, the new footwear change the movement, showing a more upright stance. Also, the new footwear reduce joint loading at the joint during the landing and weight acceptance phase of walking. However, the influence of the new footwear is immediate and does rut change after wearing the shoes for two weeks.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.28 no.1
• /
• pp.95-105
• /
• 2001

The present study was designed to compare morphological and structural relationships between basicranial measurements such as MCF angulation (Ar-SE-ptm), saddle angle (N-S-Ba, N-S-Ar) and facial structures including types of malocclusion. Twenty six children with Class III whose longitudinal headfilms were available from 7 to 12-year-old, and also 26 cross-sectional headfilms at each ages of 8, 9, 10 and 11 with Class I were selected for the investigation. Cephalometric measurements such as Ar-SE-ptm, N-S-Ba, N-S-Ar, N-SE-Ar, SNA, SNB, N-S/PM vert, CP/PM vert, $\underline{1}/FH$ plane, and $N-perp/\underline{1}$ were measured. Morphologic relationships and pattern of changes in facial structures in relation to the changes of MCF and saddle angle in both malocclusion types were analysed statistically employing ANOVA, t-test and Pearson correlation. Results suggest that the MCF rather than the saddle angle in children with Class I and III is more closely related with various facial structures and with their changes. It may be, therefore, suggested that the MCF be one of the biologically meaningful measurements in determining structural relationships between cranial base and facial complex including types of malocclusion. In addition, the MCF and its correlated facial structures in children with Class III, interestingly, showed somewhat marked changes between the ages of 9 and 11.

• Journal of the Korean Applied Science and Technology
• /
• v.38 no.2
• /
• pp.532-542
• /
• 2021

The purpose of this study was to investigate the body's strategy through kinematic variables of the lower extremities and ground reaction forces to maintain the club-head speed and ball accuracy despite the three stances during the golf swing. Ten male golfers who official handicap two were participate in the experiment. All subjects performed swing after maintaining the address posture according to stance conditions(square; SS, open: OS, closed: CS). Using a 3D motion analysis system and force plateform, the results were calculated with the 7-iron full swing each stance. In result, there was no difference in center of displacement, and left and right hip and knee joint angle displacement. Left ankle joint was largely plantar-flexed in OS, and right ankle joint was largely performed in CS from the address to the downswing. From address to take-back, right foot had a large left direction and the left foot had a right direction were greater in OS than in CS. Therefore, despite various stances, maintaining the same posture at impact is thought to have a positive effect on club head speed and ball direction.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.6
• /
• pp.2773-2779
• /
• 2013

The purpose of this study was to evaluate of the usefulness and to develop new auxiliary equipment that can bending angle of the bone of the knee various depending on the thickness of the thigh of the human. The subjects agreed for research purposes and were selected from normal person who do not have past knee-related diseases and grouped thin group A and thick group B for the thigh. We set in order to obtain images in the axial direction of the bones of the knee, $35^{\circ}$ to increase by $5^{\circ}$ angle of knee flexion, $45^{\circ}$, to $55^{\circ}$, and we performed combinations of 9 tests by incident angle X-ray per each angle, $40^{\circ}$, $50^{\circ}$ and $60^{\circ}$. As a result, we have developed an Merchant auxillary equipment of X-ray table integral type in radiographic images which was easy to use and could take images of various integral knee joint angles adjusting different body types. Using the auxiliary equipment, in the case of X-ray incident angle $50^{\circ}$ and $60^{\circ}$ with the knee flexion angle of $40^{\circ}$ in group A, and in group B, Knee flexion angle of $45^{\circ}$ and $35^{\circ}$, the X-ray incident angle at $60^{\circ}$, excellent images were derived. Future, it would be very useful in the examination of patients with a variety of body types.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.12
• /
• pp.5677-5683
• /
• 2011

The purpose of this study was to determine the effects of hip flexion angles and Kinesio-taping on lumbar extension strength. Forty healthy participants(male=20, female=20) were volunteered for this study. It was used to measure lumbar extension strength with the back strength dynamometer in five angles($0^{\circ}$, $20^{\circ}$, $40^{\circ}$, $60^{\circ}$ & $80^{\circ}$ hip flexion). It was used to estimate and compare back extension strength with independent t-test, paired t-test, correlation analysis and ANOVA. The results of this study were as follows; First, lumbar extension strength was the most achieved at $40^{\circ}$ hip flexion in male and female(p<0.05). Second, lumbar extension strength was showed a statically increase(p<0.05) in $0^{\circ}$, $20^{\circ}$, $40^{\circ}$, $60^{\circ}$ and $80^{\circ}$(except male) after appling taping. These results proposed to us the conclusion that back muscle strength was influenced by hip flexion angles and Kinesio-taping in the lifting work.

• Clinics in Shoulder and Elbow
• /
• v.10 no.1
• /
• pp.99-105
• /
• 2007

Purpose: The morphological study and dynamic stability of the ulnar nerve around the elbow joint was investigated in asymptomatic normal population using ultrasonography. The purpose of this study is to provide fundamental data for ultrasonographic diagnosis of ulnar neuropathy in cubital tunnel syndrome. Materials and Methods: Fifty cases of 25 healthy male volunteers, aged between 20 to 30 years, included in this study. High resolution 7.5 MHz linear probe was used to examine the ulnar nerve in axial and longitudinal views. In a longitudinal view, the course, position and the thickness of nerve were monitored, the diameter of ulnar nerve and dynamic stability at elbow flexion and extension were measured in an axial view at four different points; 1cm proximal to medial epicondyle, behind the medial epicondyle, entrance to Osborne ligament, and 1cm distal to Osborne ligament. Results: The short diameters of ulnar nerve at elbow extension at four anatomic points were 2.66 mm, 2.97 mm, 2.64 mm, and 2.69 mm and the long diameters were 4.61 mm, 4.56 mm, 4.36 mm, and 4.37 mm, which showed no significant change at each point. However, at elbow flexion, the short diameters were changed to 2.72 mm, 2.34 mm, 2.65 mm, and 2.41 mm and the long diameters into 4.49 mm, 5.40 mm, 4.16 mm, and 4.66 mm. At elbow flexion, significant morphologic change was observed in the medial epicondyle area, and the diameter of the ulnar nerve was shortest at the entrance of Osborne ligament both at flexion and extension. In terms of dynamic stability, nine subluxations and seven dislocations were observed. Conclusion: This study shows dynamic instability and a morphological change of long and short diameters of ulnar nerve at flexion and extension in a normal person, which should be considered in the ultrasonographic diagnosis of ulnar neuropathy.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.1
• /
• pp.1-7
• /
• 2015

This paper predicts the spring-in effect of curved laminated composite structure for various stacking sequence using finite element analysis(ABAQUS). In composite manufacturing process, large temperature difference, different coefficient of thermal expansion and chemical shrinkage effect cause distortion of composite parts such as spring-in and warpage. Distortion of composite structure is important issue on quality of product, and it should be considered in manufacturing process. In finite element analysis, a CHILE(Cure Hardening Instantaneously Linear Elastic) model and chemical shrinkage effects are considered developing user subroutine in ABAQUS and some cases are simulated.

• The korean journal of orthodontics
• /
• v.36 no.4
• /
• pp.284-294
• /
• 2006

Objective: Activating mutations in the fibroblast growth factor receptor-2 (FGFR2) have been shown to cause syndromic craniosynostosis such as Apert and Crouzon syndromes. The purpose of this pilot study was to investigate the resultant phenotypes induced by the two distinctive bone-targeted gene constructs of FGFR2, Pro253Arg and Cys278Phe, corresponding to human Apert and Crouzon syndromes respectively. Methods: Wild type and a transgenic mouse model with normal FGFR2 were used as controls to examine the validity of the microinjection. Micro-CT and morphometric analysis on the skull revealed the following results. Results: Both Apert and Crouzon mutants of FGFR2 induced fusion of calvarial sutures and anteroposteriorly constricted facial dimension, with anterior crossbite present only in Apert mice. Apert mice differed from Crouzon mice and transgenic mice with normal FGFR2 in the anterior cranial base flexure and calvarial flexure angle which implies a possible difference in the pathogenesis of the two mutations. In contrast, the transgenic mice with normal FGFR2 displayed normal craniofacial phenotype. Conclusion: Apert and Crouzon mutations appear to lead to genotype-specific phenotypes, possibly causing the distinctive sites and sequence of synostosis in the calvaria and cranial base. The exact function of the altered FGFR2 at each suture needs further investigation.

• The Journal of Korean Academy of Prosthodontics
• /
• v.47 no.2
• /
• pp.191-198
• /
• 2009

Statement of problem: Ceramics have been important materials for the restoration of teeth. The demands of patients for tooth-colored restorations and the availability of various dental ceramics has driven the increased use of new types of dental ceramic materials. Improved physical properties of theses materials have expanded its use even in posterior crowns and fixed partial dentures. However, ceramic still has limitation such as low loading capability. This is critical for long-span bridge, because bridge is more subject to tensile force. Purpose: The wire reinforced ceramic was designed to increase the fracture resistance of ceramic restoration. The purpose of this study was to evaluate the fracture resistance of wire reinforced ceramic. Material and methods: Heat pressed ceramic(ingot No.200 : IPS Empress 2, Ivoclar Vivadent, Liechtenstein) and Ni-Cr wire(Alfa Aesar, Johnson Matthey Company, USA) of 0.41 mm diameter were used in this study. Five groups of twelve uniform sized ceramic specimens(width 4 mm, thickness 2 mm, length 15 mm) were fabricated. Each group had different wire arrangement. Wireless ceramic was used as control group. The experimental groups were divided according to wire number and position. One, two and three strands of wires were positioned on the longitudinal axis of specimen. In another experimental group, three strands of wires positioned on the longitudinal axis and five strands of wires positioned on the transverse axis. Three-point bending test was done with universal testing machine(Z020, Zwick, Germany) to compare the flexural modulus, flexural strength, strain at fracture and fracture toughness of each group. Fractured ceramic specimens were cross-sectioned with caborundum disc and grinded with sandpaper to observe interface between ceramic and Ni-Cr wire. The interface between ceramic and Ni-Cr wire was analyzed with scanning electron microscope(JSM-6360, JEOL, Japan) under platinum coating. Results: The results obtained were as follows: 1. The average and standard deviation in flexural modulus, flexural strength and fracture toughness showed no statistical differences between control and experimental groups. However, strain was significantly increased in wire inserted ceramics(P<.001). 2. Control group showed wedge fracture aspects across specimen, while experimental groups showed cracks across specimen. 3. Scanning electron microscopic image of cross-sectioned and longitudinally-sectioned specimens showed no gap at the interface between ceramic and Ni-Cr wire. Conclusion: The results of this study showed that wire inserted ceramics have a high strain characteristic. However, wire inserted ceramics was not enough to use at posterior area of mouth in relation to flexural modulus and flexural strength. Therefore, we need further studies.

• Science of Emotion and Sensibility
• /
• v.21 no.4
• /
• pp.55-62
• /
• 2018

The two main requirements of wearable optical fiber fabrics are that they must presuppose a high degree of flexibility and they must maintain the luminance effect in both flat and bent conformations. Therefore, woven optical fiber fabrics that satisfy the above conditions were developed by both weaving and by using computer embroidery. First, we measured the brightness of the wearable optical fiber fabric in the flat state at a total of 10 measurement points at intervals of 1 cm. Second, the wearable optical fiber fabric was placed horizontally on the forearm, where three-dimensional bending occurs, and the luminance values were recorded at the same 10 measurement points. For the woven fabric in the flat state, the maximum, minimum, average, and standard deviation luminance values were $5.23cd/m^2$, $2.74cd/m^2$, $3.56cd/m^2$, and $1.11cd/m^2$, respectively. The corresponding luminance values from the bent forearm were $7.92cd/m^2$ (maximum), $2.37cd/m^2$ (minimum), $4.42cd/m^2$ (average), and $2.16cd/m^2$ (standard deviation). In the case of the computer-embroidered fabric, the maximum, minimum, average, and standard deviation luminance values in the flat state were $7.56cd/m^2$, $3.84cd/m^2$, $5.13cd/m^2$, and $1.04cd/m^2$, respectively, and in the bent forearm state were $9.6cd/m^2$, $3.63cd/m^2$, $6.13cd/m^2$, and $2.26cd/m^2$, respectively. Therefore, the computer-embroidered fabric exhibited a higher luminous effect than the woven fabric because the detailed structure reduced light-loss due to the backside fabric. In both types of wearable optical fiber fabric the luminance at the forearm was 124% and 119%, respectively, and the light emitting effect of the optical fiber fabric was maintained even when bent by the human body. This is consistent with the principle of Huygens, which defines the wave theory of light, and also the Huygens-Fresnel-Kirchhoff principle, which states that the intensity of light increases according to the magnitude of the angle of propagation of the light wavefront (${\theta}$).