• The Journal of the Korean dental association
• /
• v.12 no.2
• /
• pp.123-129
• /
• 1974

The electrical activities of masseter muscle were recorded on 9 subjects with unilateral fracture of mandible. The electromyographic studies were executed with 2 channel RS dynograph recorder for electromyography. The graphs were recorded in the physiologic rest position, incisal occlusion, molar occlusion, left lateral excursion, right lateral excursion, and protraction. The following conclusions were drawn; 1. In the physiologic rest position, incisal occlusion, molar occlusion, and protraction, the electrical potentials of the masseter muscle were greater in the affected side. 2. In the right lateral excursion, the electrical potentials of the masseter muscle were greater in the right side, and in the left lateral excursion, greather in the left side. There is no correlation mutually between the affected side and unaffected side.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1440-1444
• /
• 2011

Memory-device is one of the auxiliary components of point-switch machine; connecting front-rod and tongue-rail. The right side and left side of memory-device are different from each other. When there would be a derailing accident of rolling stock or motor-car, the memory-device properly bends and protects the internal of point-switch machine. Memory-device is one of the important site maintenance spare parts. Memory-device for each of right and left side should be secured so that they can be installed on correct side during an exchange work. This study suggests the development of memory-device with different left and right side and the performance test of it. The study intends to contribute in the convenience improvement of maintenance by improving the unification of memory-device.

• The Journal of Korean Physical Therapy
• /
• v.14 no.4
• /
• pp.1-19
• /
• 2002

The purpose of this study is to identify influence that eye movement have an effect on postural control and balance performance by plegia side of the impaired patients of central nervous system. Subjects are patients with the impairment of central nervous system and experimental and control groups are forty people and thirty people seperatively, Total subjects were selected to seventy persons, but twelve persons of experimental group quit during the experimental periods and eight persons of control group did not measure after exercise. Therefore, twenty eight persons of experimental group and twenty two persons of control group were selected in this study and experimental group peformed eye movement for eight weeks according to the exercise program of this study. The measurement of dependent variable is right static balance, left static balance, bilateral static balance, and bilateral dynamic balance before exercise and after eighth week of exercise, examiner again measured and analyzed the results. The results were as follows: 1. As the result of comparing balance performance ability after test of the experimental and control group with right hemiplegia and control group, all of static balance performance ability of right side (p < 0.01), static balance performance ability of left side (p < 0.01), static balance performance ability of bilateral side(p < 0.01), dynamic balance performance ability of bilateral side(p < 0.05) of experimental group were statistically greater improved than those of the control group. 2. As the result of comparing balance performance ability after test of the experimental and control group with left hemiplegia and control group, all of static balance performance ability of right side (p < 0.01), static balance performance ability of left side (p < 0.01), static balance performance ability of bilateral side(p < 0.05), dynamic balance performance ability of bilateral side(p < 0.05) of experimental group were statistically greater improved than those of the control group.

• Journal of the Ergonomics Society of Korea
• /
• v.28 no.2
• /
• pp.9-16
• /
• 2009

The aim of this study was to evaluate the effects of the driving performance and workload according to changing driving environment and types of steering wheel. Twelve drivers who participated in this study consisted of two groups; six Japanese as the left-lane drivers who was accustomed to driving on left-hand side of the road, and six Europeans, Americans, and Korean as the right-lane drivers who was accustomed to driving on right-hand side of the road. They were asked to operate a driving simulator while using two different types of steering wheel (for the left-hand side driving and the right-hand side driving). During the experiment, a range of data were measured including driving performance, mental workload, and eye movements which were recorded in order to identify the amount of time looking towards the in-vehicle route guidance. Results indicated that the use of the steering wheel by parallel moving led to increase high attentional demand and worse glance behavior to traffic signs for the left-lane drivers. In the case of the right-lane drivers, the effects by changing driving direction were more effective than the types of steering wheel due to their habit or traits.

• Korean Journal of Applied Biomechanics
• /
• v.25 no.4
• /
• pp.423-429
• /
• 2015

Objective : The purpose of this study was to investigate the effects of a body alignment correction program on asymmetrically developed squash players. Method : 30 experienced squash players who showed asymmetric body development, after evaluation of moire topography contour line shape, were involved in the experiment. All of them were right-handed and had more than five years of experience playing squash. Variables of body composition, moire topography and EMG were statistically compared between pre- and post- application of the 12-week body alignment correction program. The program consisted of 10-minute, left-handed forehand and backhand drive movements and 36 minutes performing 12 different yoga postures. Results : First, the body alignment correction program showed significant effects on the total weight, body fat percentage, and body mass index of the participants. Second, a decrease of right side inclined angles and an increase of left side inclined angles might result in a higher left-right symmetry rate and a better left-right balance; however the data was not statistically significant. Third, the EMG left-right deviation of erector spinae and latissimus decreased and the erector spinae muscle was thought to be more essential for vertebral movement and left-right asymmetry correction. Conclusion : A body alignment correction program, including yoga and opposite side exercises, could reduce left-right asymmetry.

• Journal of Korean Physical Therapy Science
• /
• v.16 no.4
• /
• pp.59-65
• /
• 2009

Background: Human body is formed of symmetric bilateral structures that are comprised of eye, upper arm, lower arm and etc. but, we are used only dominant components. The purpose of this study was to analysis length cognition ability in dominant eye & hand. Method: Total 180 persons (male 32, female 138) were participated in this study. They were tested with 'hole in the card' test for identification of dominant eye's side and the question for identification of dominant hand's side, then the length cognition ability was measured in right & left axillary level by describing 10cm line. Results: The results by independent t-test were as follows. In difference of length cognition ability in right axillary level between right dominant eyed group & left dominant eyed group, right dominant eyed group was superior to left dominant eyed group, but significant difference was not existed statistically(p>.05). In left axillary level, right dominant eyed group was superior to left dominant eyed group, but significant difference was not existed statistically(p>.05). In axillary level of dominant eye's side, non-crossed group was superior to crossed group, but significant difference was not existed statistically(p>.05). In axillary level of non-dominant eye's side, non-crossed group was superior to crossed group, but significant difference was not existed statistically(p>.05). Conclusion: These result can be applied to the learning of palpation & observation skill in physical therapy.

• Korean Journal of Applied Biomechanics
• /
• v.29 no.1
• /
• pp.23-32
• /
• 2019

Objective: The aim of this study was to provide kinematic data on the characteristics of spinal disease patients by comparing and analyzing kinematic variables related to foot balance and gait pattern of spinal disease. Method: The subjects of the study included 40 adult men and 60 adult women who visited the hospital in Busan. Patients who were diagnosed with spinal disease by a physician through X-ray examination were selected as subjects for the diagnosis of vertebral disc herniation, spinal stenosis, spinal disease diagnosed with spinal disease and the general public. Left and right foot pressure and contact area were checked by Gaitview pro meter. X-ray photographs were taken with a Zen-2090 mobile fluoroscopy under physicians' direct participation. One-way ANOVA was performed to compare the differences between the kinematic variables and post-hoc was performed by the Duncan method. Results: The difference in contact area between the left foot and the right foot was $115.30{\pm}14.15cm^2$ in the left side and $124.25{\pm}13.65cm^2$ in the left side in the spinal disease patients. The difference in pressure between the left and right side of the spinal disease patients was wider than that of the general people. Especially, the right side of the spinal disease patients showed a larger area of left foot contact than the general population. Conclusion: Spinal disease patients have wider contact area of the left foot than those of the general population. In the case of right spinal disease, the left foot support area is widened due to pain. In the gait, women showed slightly more posterior body center than men, and the upper body muscle imbalance and immobilization due to the spinal disease caused imbalance of the muscles moving to the lower limb, It was analyzed to inhibit movement.

• Journal of Biosystems Engineering
• /
• v.42 no.3
• /
• pp.127-135
• /
• 2017

Purpose: Purpose: The usability of a mathematical model modified for analysis of the static stability of an asymmetric tractor-harvester system was investigated. Method: The modified asynchronous mathematical model was validated through empirical experiments, and the effects of movements of the center of gravity (CG) coordinates on the stability against lateral overturning were analyzed through simulations. Results: Changes in the lateral overturning angle of the system were investigated when the coordinates of the CG of the system were moved within the variable range. The errors between simulation results and empirical experiments were compared, and the results were -4.7% at the left side overturning and -0.1% at the right side overturning. The asymmetric system was characterized in such a way that the right side overturning had an increase in overturning angle in the (+) variable range, while it had a decrease in overturning angle in the (-) variable range. In addition, the left side overturning showed an opposite result to that of the right side. At the declination angle (296<${\gamma}$<76), the right side overturning had an increase in the maximum overturning angle of 3.6%, in the minimum overturning angle of 20.3%, and in the mean overturning angle of 15.9%. Furthermore, at the declination angle (284<${\gamma}$<64), the left side overturning had a decrease in the maximum overturning angle of 29.2%, in the minimum overturning angle of 44%, and in a mean overturning angle of 39.7%. Conclusion: The modified mathematical model was useful for predicting the overturning angle of the asymmetric tractor-harvester system, and verified that a movement of the CG coordinates had a critical effect on its stability. In particular, the left side overturning was the most vulnerable to stability, regardless of the direction of declination angle.

• Imaging Science in Dentistry
• /
• v.51 no.1
• /
• pp.49-54
• /
• 2021

Purpose: This study was conducted to establish age- and sex-specific reference standards for pterygoid hamulus(PH) dimensions using cone-beam computed tomography (CBCT). Materials and Methods: CBCT scans of 1,000 patients(493 males and 507 females) were retrospectively assessed in coronal sections for length and width measurements of the PH by 3 investigators. The study data were divided into 3 age groups(group 1: <20 years, group 2: 20-50 years, group 3: >50 years). Length and width were compared using one-way analysis of variance and the t-test for age and sex, respectively. Results: The length of the PH on the right side significantly increased from group 1 (6.11±1.47mm), through group 2 (6.65±1.67 mm) to group 3 (6.99±1.79 mm) and on the left side from group 2 (6.58±1.63) to group 3 (6.98±1.70). The width of the PH significantly decreased from group 1 (1.81±0.39 mm) to group 2 (1.61±0.39 mm) on the right side, and similarly from 1.87±0.36mm to 1.67±0.37mm on the left side. PH length (7.18±1.81mm on the right side and 7.10±1.72 mm on the left side) and width (1.68±0.38 mm on the right side and 1.74±0.36 mm on the left side) were significantly greater in males than in females. Conclusion: The length of the PH increased with age, whereas width first decreased and then increased. Length and width measurements were significantly higher in males than in females. These findings will aid in the diagnosis of untraceable pain in the oropharyngeal region related to altered PH morphology.

• Journal of the Korea Safety Management & Science
• /
• v.4 no.2
• /
• pp.1-10
• /
• 2002

In order to protect the head, baseball helmet must to have proper strength and to absorb the kinetic energy. The purposes of this study are to validate whether the helmet have the protecting ability or not. We performed three kinds of experiment to know about the this ability. To find out the limit of displacement at 4 points(front, rear, right side, and left side), the static load by magnetic dial gauges were used, and to validate the ability of absorption, drop tests were peformed from 0.5 and 1.0 meter. Futhermore, we calculated natural frequency of the helmets by the principle of Lissajous Diagram and we performed FEM(Finite Element Method) analysis. From the results of these experiments, we found that the displacement of helmet was largest at rear point and it was smallest at left-side point(ear-covered part). The ability of absorption was better at the left-side point than the other points.