• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.97-108
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• 2006

C. H. OH, S. N. CHOI, T. G. NAM, The Kinematic Analysis of the Tennis Flat Serve Motion, Korean Jiurnal of Sports Biomechanics, Vol. 16, No. 2, pp. 97-108, 2006. By the comparison and the analysis of the different factors during the tennis flat serve motion such as the required time per section, the movement displacement of the racket, the velocity of the upper limbs joints, the physical center of gravity, and the angle and the angular velocity of the upper limbs joints between an ace player and a mediocre player, these following results were drawn. First, the experiment result of the total time required per section in a tennis flat serve motion showed that an ace player was faster than a mediocre player by 0.4 seconds. This result suggested that it was required to increase the speed of the racket head by a swift swing to perform an effective flat serve motion. Second, the experiment result of the movement displacement of the racket in the tennis flat serve motion showed that an ace player greatly moved toward the left side on an x-axis. But both an ace and a mediocre player were shown to be at the similar points on a y-axis at the moment of the impact of the racket. An ace player was also shown to be located at a higher position on a z-axis by 0.23m. Third, the velocity of the center of gravity of an ace player was faster in every phase than that of a mediocre player in a tennis flat serve motion. Fourth, the velocity of the upper limb joints of an ace player was faster in every phase than that of a mediocre player in a tennis flat serve motion. Fifth, the experiment result of the speed of the racket head in tennis flat serve motion showed that a mediocre player was faster than an ace player in the first phase, but the latter was faster than the former in the second, third, and the fourth phases. Sixth, at the moment of impact of a tennis flat serve, an ace player had greater flexion of the angle of the wrist joints by an 11.8 degree than a mediocre player. An ace player also had greater extension of the angle of the elbow joint and the shoulder joint respectively by a 5.2 degree and a 1.4 degree with a mediocre player. Seventh, an ace player had greater angular velocity of the upper limb joints and the hip joints than a mediocre player at the moment of the impact of tennis flat serve. Eighth, an ace player was shown to have a greater change of the forward and the backward inclination (or the anterior and posterior inclination) of the upper body

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.145-153
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• 2007

The purpose of this study is to compare and analyze the phase-by-phase elapsed time, the COG, the body joint angle changes and the angular velocities of each phase of Handspring Salto Forward Piked performed by 4 college gymnasts through 3D movement analysis program. 1. The average elapsed time for each phase was .13sec for Phase 1, .18sec for Phase 2, .4sec for Phase 3, and .3sec for Phase 5. The elapsed time for Phase 1 to Phase 3 handspring was .35sec on average and the elapsed time for Phase 4 to Phase 5 handspring salto forward piked was .7sec on average. And so it showed that the whole elapsed time was 1.44sec. 2. The average horizontal changes of COG were 93.2 cm at E1, 138. 5 cm at E2, 215.7 cm at E3, 369.2 cm at E4, 450.7 cm at E5, and 553.1 cm at E6. The average vertical changes of COG were 83.1 cm at E1, 71.3 cm at E2, 78.9 cm at E3, 93.7 cm at E4, 150.8 cm at E5, and 97.2 cm at E6. 3. The average shoulder joint angles at each phase were 131.6 deg at E1, 153.5 deg at E2, 135.4 deg at E3, 113.4 deg at E4, 39.6 deg at E5, and 67.5 deg at E6. And the average hip joint angles at each phase were 82.2 deg at E1, 60 deg at E2, 101.9 deg at E3, 161.2 deg at E4, 97.7 deg at E5, and 167 deg at E6. 4. The average shoulder joint angular velocities at each phase were 130.9deg/s E1, 73.1 deg/s at E2, -133.9 deg/s at E3, -194.4 deg/s at E4, 29.4 deg/s at E5, and -50.1 deg/s at E6. And the average hip joint angular velocities at each phase were -154.7 deg/s E1, -96.5 deg/s at E2, 495.9 deg/s at E3, 281.5 deg/s at E4, 90.3 deg/s at E5, and 181.7 deg/s at E6. The results shows that, as for the performance of handspring salto forward piked, it is important to move in short time and horizontally from the hop step to the point to place the hands on the floor and jump, and to stretch the hip joints as much as possible after the displacement of the hands and to keep the hip joints stretched and high in the vertical position at the takeoff. And it is also important to bend the shoulder joints and the hip joints fast and spin as much as possible after the takeoff, and to decrease the speed of spinning by bending he shoulder joints and the hip joints quickly after the highest point of COG and make a stable landing.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.133-140
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• 2015

Purpose: It was investigated whether two different stabilization designs of toric contact lenses changed the rotational axis and degree of toric lenses according to body posture and gaze direction in the present study. Methods: Toric soft contact lenses with Lo-Torque$^{TM}$ design and ASD design (accelerated stabilized design) were fitted on 52 eyes aged in 20s-30s. Then, rotational degree was measured at the five gaze directions including front gaze and the lying position. Results: When gazing the front and vertical directions in the upright posture, lens was much rotated to nasal side for the Lo-Torque$^{TM}$ design and temporal side for the ASD design. When gazing horizontal direction, both design lenses were rotated against to the gaze direction. Rotation degree was the smallest at superior direction gaze and the largest at nasal gaze. In case of the rotation degree less than $5^{\circ}$, Lo-Torque$^{TM}$ design was more frequent when gazing front and vertical directions, and ASD design was more frequent when gazing horizontal direction. In addition, the lens with Lo-Torque$^{TM}$ design was lesser rotation degree than with ASD design immediately after lying. On the other hand, the lens with ASD design was lesser rotation degree than with Lo-Torque$^{TM}$ design 1 minute later after lying. Conclusions: This study confirmed that axis rotation of the lens induced by gaze direction and posture was different according to axis stabilization design during wearing toric soft contact lens.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.2
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• pp.99-104
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• 2007

The skin barrier function is one of the vital functions. Horny layer and epidermis among various skin layers play an important role in protecting body from environmental insults. Stratum corneum is completely formed by differentiation processes from the basal layer and newly formed corneocytes push the older ones from skin surface. In this study we investigated changes of various parameters - capacitance, transepidermal water loss (TEWL), pH and amount of removed corneocytes - according to the stratum corneum's depth. We removed the stratum corneum using tape stripping technique. We found that uppermost stratum corneum play an important role in skin surface moisturization and lower stratum corneum in protecting transepidermal water loss. In addition, skin pH is more acidic than surface pH. In the stratum corneum, skin pH is mote acidic in the deeper layer. Furthermore amount of removed corneocyte is also decreased according to depth because of stronger cell-cell union strength. From these results we suggest that stratum corneum has different characteristics depending on their position.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.337-347
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• 2016

This study is aimed at figuring out the stress of workers in the field of railroad electricity and vehicles and its convergence factors. The workers were divided into the workers in the headquarters and in the field. A self-administered survey was conducted from February 9 to March 6 in 2015. 628 respondents' reply was analyzed by PASW Statistics Ver. 18.0. As the result, 94.7% of them belonged to the over weight group and frequently drank alcohol. The stress score was higher in the workers in the headquarters(3.00/5.00) than those in the field(2.85). For the workers in the headquarters, those who smoke everyday showed higher stress level than that of those who have never smoked while stress level decreased in those who are satisfied with their company life. For the workers in the field, stress increased in the higher age group than those in their the twenties and those who skip their breakfast. The more positive their subjective awareness toward their body shape and the more satisfied they were with their company life, the more their stress level decreased. Therefore, the study suggests that we have to focus on those who are vulnerable to stress using the factors.

• Journal of Technologic Dentistry
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• v.18 no.1
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• pp.95-115
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• 1996

The esthetic factor for the esthetic prosthesis were studied on 300 persons. The praaticipants were 150 students registered under the Deparment of Dental Laboratoy Technology, Jisan Junior College at the present day of June, 1995 and their mothers. The results were as follows; 1. The number of persons with 28 teeth in their oralcatity was highest(P<0.01). They complained that they have only 28 teeth bacaues of the loss(deficiency) fo teeth due to their impacted teeth and dental caries. 2. The presons with feelings of dissatisfaction were large in number(P<0.01). They were dissatisfied with an abnormal tooth form(33.5%), tooth position(31.7%), tooth color(31.1%), and tooth size(3.7%) in order(P<0.01). 3. In their facial form, the most numerous were men with square form and women with ovoid form(P<0.01). Among the whloe number fo facial forms it appeared to decresae in the order of ovoied(41.8%), square(32.7%), square+tapered(20.5%), and tapered form(5%)(P<0.01). In a profile form, the most numerous were men with A form and women with B. Among the whole participants the most numerous were persons with B form and persons with A and C form were next in oder of numbers(P<0.01). 4. In discoloration of teeth, the most numerous were persons who have no discoloration. 5. In the esthetic recovery of anterior prosthesis the color matching of proximal teeth was not correct, but the outline of proximal teeth was to be reproduced correctly. 6. In the diastema of teeth, the number of persons who have no diastema was higher than that of persons who have a disatema(P<0.01) Among the persons who have diastema the most numerous were persons who have a diastema, and next were 2, 4, 3 and 5 diastemas in order. 7. In a meeting point of the midline of the body and the tooth the number of person hanving a meeting point was higher than that of persons who did not fit each other(P<0.01). The bias direction of midline teeth appeared to be affected by chewing direction, prosthesis location, and posterior location. 8. The length and width of teeth in the tooth size were suitable(P<0.01). The number of persons who have central teeth longer than lateral teeth was high(P<0.0). 9. In the results of smile analysis, the line form connected with incisal edge of upper canine were parallel(P<0.01). When smile the location fo upper lips should be in accord with the central area of teeth(P<0.01) and lower lip should be atteched to the edge of anterior teeth in order to be esthetic. 10. Among the number of upper teeth we can see the most numerous were 8 teeth and next were 10, 6 and 12 in order.

• Journal of Oriental Medical Thermology
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• v.5 no.1
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• pp.1-13
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• 2006

Objectives : This study was designed to analyze basic data for cold hypersensitivity patients with a questionnaire and investigate correlation between cold hypersensitivity and Heart Rate Variability(HRV). Methods : 49 patients who complain of cold hypersensitivity on hands and feet in ambulatory care were investigated in Oriental Gynecology, Kyunghee Oriental Medical Center and Women medical center, Kangnam Koreana hospital from May 1, 2006 to October 20, 2006. All patients were asked to answer a questionnaire. After careful I examination to rule out other disease which may affect Digital Infrared Thermal Imaging(DITI) and HRV data, patients were taken thermography for the diagnosis of cold hypersensitivity Based on the result of thermography, the patients were divided into two groups(Objective cold hypersensitivity and Subjective cold hypersensitivity). Then, these two groups were compared using HRV data which was measured in the supine position for 5 minutes. Results: 1. For most patients, cold hypersensitivity first developed during puberty. 2. The parts of the body that felt cold first time were hands and feet. 3. The cold sensation was increased in winter or at bedtime Showing that the sensation can be changed according to the level of coldness. 4. Among women who sufferfrom cold hypersensitivity, very few of them were treated. 5. More than half of cold hypersensitivity patients's family member also had a cold hypersensitivity. 6. The decrease in mean values of LF/HF ratio was observed in objective cold hypersensitivity group than subjective cold hypersensitivity group and the decrease was significant(P=0.014) when examined by Student t-test. Conclusions : It is necessary that the cold hypersensitivity patients should be treated carefully considering the facts mentioned above. And it can be suggested that dysautinomia be related with cold hypersensitivity and be evaluated by HRV.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.27-37
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• 2006

Although the main purpose of periodontal treatment to regenerate is the complete regeneration of periodontal tissue due to periodontal disease, most of the treatment cannot meet such purpose because healing by long epithelial junction. Therefore, diverse materials of resorbable and non-resorbable have been used to regenerate the periodontal tissue. Due to high risk of exposure and necessity of secondary surgical procedure when using non-resorbable membrane, guided tissue regeneration using the resorbable membrane has gain popularity, recently. However, present resorbable membrane has the disadvantage of not having sufficient time to regenerate date to the difference of resorption rate according to surgical site. Meanwhile, other than the structure stability and facile manipulation, acellular dermal matrix has been reported to be a possible scaffold for cellular proliferation due to rapid revascularization and favorable physical properties for cellular attachment and proliferation. The purpose of this study is to estimate the influence of acellular dermal matrix on periodontal ligament, cementum and alveolar bone when acellular dermal matrix is implanted to 1-wall alveolar bone defect. 4 dogs of 12 to 16 month old irrelevant to sex , which below 15Kg of body weight, has been used in this study. ADM has been used for the material of guided tissue regeneration. The 3rd premolar of the lower jaw was extracted bilaterally and awaited for self-healing. subsequently buccal and lingual flap was elevated to form one wall intrabony defect with the depth and width of 4mm on the distal surface of 2nd premolar and the mesial surface of 4th premolar. After the removal of periodontal ligament by root planing. notch was formed on the basal position. Following the root surface treatment, while the control group had the flap sutured without any treatment on surgically induced intrabony defect. Following the root surface treatment, the flap of intrabony defect was sutured with the ADM inserted while the control group sutured without any insertion. The histologic specimen was observed after 4 and 8 weeks of treatment. The control group was partially regenerated by periodontal ligament, new cementum and new alveolar bone. the level of regeneration is not reached on the previous formed notch. but, experimental group was fully regenerated by functionally oriented periodontal ligament fiber. new cementum and new alveolar bone. In conclusion, we think that ADM seems to be used by scaffold for periodontal ligament cells and the matrix is expected to use on guided tissue regeneration.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.10
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• pp.427-436
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• 2013

In this paper, a method of moving path control of an automatic guided vehicle in an indoor environment through recognition of marker images using vision sensors is presented. The existing AGV moving control system using infrared-ray sensors and landmarks have faced at two critical problems. Since there are many windows in a crematorium, they are going to let in too much sunlight in the main hall which is the moving area of AGVs. Sunlight affects the correct recognition of landmarks due to refraction and/or reflection of sunlight. The second one is that a crematorium has a narrow indoor environment compared to typical industrial fields. Particularly when an AVG changes its direction to enter the designated furnace the information provided by guided sensors cannot be utilized to estimate its location because the rotating space is too narrow to get them. To resolve the occurrences of such circumstances that cannot access sensing data in a WSN environment, a relative distance from marker to an AGV will be used as fingerprinting used for location estimation. Compared to the existing fingerprinting method which uses RSS, our proposed method may result in a higher reliable estimation of location. Our experimental results show that the proposed method proves the correctness and applicability. In addition, our proposed approach will be applied to the AGV system in the crematorium so that it can transport a dead body safely from the loading place to its rightful destination.

• Investigative Magnetic Resonance Imaging
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• v.7 no.2
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• pp.108-115
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• 2003

Purpose : To evaluate the effect of the gradient switching noise on the ECD source localization with the EEG data recorded during the MRI scan. Materials and Methods : We have fabricated a spherical EEG phantom that emulates a human head on which multiple electrodes are attached. Inside the phantom, electric current dipole(ECD) sources are located to evaluate the source localization error. The EEG phantom was placed in the center of the whole-body 3.0 Tesla MRI magnet, and a sinusoidal current was fed to the ECD sources. With an MRI-compatible EEG measurement system, we recorded the multi channel electric potential signals during gradient echo single-shot EPI scans. To evaluate the effect of the gradient switching noise on the ECD source localization, we controlled the gradient noise level by changing the FOV of the EPI scan. With the measured potential signals, we have performed the ECD source localization. Results : The source localization error depends on the gradient switching noise level and the ECD source position. The gradient switching noise has much bigger negative effects on the source localization than the Gaussian noise. We have found that the ECD source localization works reasonably when the gradient switching noise power is smaller than $10\%$ of the EEG signal power. Conclusion : We think that the results of the present study can be used as a guideline to determine the degree of gradient switching noise suppression in EEG when the EEG data are to be used to enhance the performance of fMRI.