• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.245-257
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• 1998

This study was performed to measure the changes of the mandibular movement and the masticatory muscular activities - anterior temporal and masseter muscle of both side - reflected by intentional increase of anterior guidance angie. For this study, 5 volunteers (3 males and 2 females with average age of 24.0) were selected. Each volunteer had Angle's classification I and did not have any missing tooth except third molar and any extensive restorations. Metallic guide plate was made at volunteer's working model fabricated by improved dental stone and cemented to the palatal surface of maxillary central incisor using resin cement(Panavia $21^{(R)}$) and then adjusted not to give any occlusal interferences at intercuspal position. The activity of masticatory muscles and the changes of mandibular movement were recorded by EMG and Sirognathograph in Biopak analysing system(Bioresearch Inc., Milwaukee, Wisconsin, USA). Measurement was done at before experiment, immediatley after placement, 1 week after placement, immediately after removal, and 1 week after removal. The results were as follows: 1. Moderate phonetic disturbance and mild headache were occured to 3 volunteers for 2 days after setting and 1 volunteer had positive reaction to percussion and slight midline diastema. But all of these clinical signs were diappeared 1 week after removal and the other volunteer did not have any special clinical sign. 2. In the EMG of the mandibular rest position, the mean value of anterior tempotal muscle was increased immediately after placement(p<0.01) and then decreased 1 week after placement(p<0.05) and increased 1 week after removal(p<0.05) but not recovered as before experiment. The mean value of masseter muscle was decreased during the experiment period. 3. In the EMG during mandibular protrusive movement, all muscular activity was decreased during the experiment period. Reduced activity was not recovered 1 week after removal(p<0.03). 4. During the habitual opening, anteroposterior movement of mandible was decreased immediately after placement(p<0.05) and then increased 1 week after placement but not statistically significant(p>0.1). Vertical movement was not shown significant difference during the experiment period(p>0.1). Lateral movement was decreased immediately after placement(p<0.05) and then increased 1 week after placement but not recovered as before experiment. The opening and closing velocity of mandible was shown minor changes but not statistically significant. 5. During the habitual opening, anteroposterior movement of mandible was decreased 1 week after placement(p<0.05) and then increased immediately after removal and recovered 1 week after removal as before experiment. Vertical movement was not shown significant changes. Lateral displacement of mandible was increased continuously and recovered 1 week after removal. Opening velocity was temporarily increased immediately after removal but recovered and closing velocity was not shown significant changes. 6. During the right side chewing, anteroposterior movement of mandible was increased immediately after removal but recovered and vertical movement was not shown statistically significant results. Lateral displacement and velocity of mandible were not shown significant results. 7. During the left side chewing, the changes of mandibular movement pattern were not shown statistically significant results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.674-677
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• 2010

The purpose of this study was to analyze bradykinesia of forearm movement in patients with Parkinson's disease (PD) as compared to those of normal subjects. A gyrosensor was selected for the measurement of forearm movement, because it can provide angular velocity signal which is free from the gravitational artifact and also because it can be conveniently used during clinical test of bradykinesia. Forty PD patients (age: $65.7\pm11.1$ yrs, H&Y stage:$2.3\pm0.5$), 14 age-matched elderly subjects ($65\pm3.9$ yrs) and 17 healthy young subjects ($24\pm2.1$ yrs) participated in this study. Angular velocity during forearm movement of pronation/supination was measured in both arms. Suggested quantitative measures of bradykinesia were root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power which were derived from the angular velocity. ANOVA showed that all measures were significantly different among three groups (p<0.001). Subsequent post-hoc test revealed that all measures in PD patients were significantly smaller than in healthy elderly and healthy young subjects (p<0.05). This results suggest that PD patients can be differentiated from normal subjects using suggested measures.

• Korean Journal of Applied Biomechanics
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• v.21 no.5
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• pp.551-560
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• 2011

The purpose of this study was to perform the kinematic analyses of the men's pole vault skills in IAAF World Championships Daegu 2011. Subjects were the 1st through 8th place finishers in the pole vault. The kinematic analyses were divided into four phases: two dimensional run up analysis, and three dimensional analyses for the remaining plant, swing up, and extension phases. Run-up variables consisted of run up distance, number of steps, average step length, the ratio of step length to his height, average velocity at the final 6~11 m, approach position. Three variables were analyzed during plant: pole angle, center of gravity (COG) velocity, and takeoff angle of COG. Swing up phase variables included: pole flexion angle, COG velocity (horizontal, vertical, resultant), COG trajectory and bar approach angle of COG. Compared to the 2009 World Championships in Berlin, the average vault height, run up velocity and approach position increased. However, horizontal velocity during the last two steps of the final approach decreased dramatically compared to speeds from 1990. These results reflect the change in both technique and improved physical fitness in pole vaulters. During extension, the peak height of COG averaged 0.3m higher then COG height when the pole was released. These specific results can help coaches and athletes modify training and improve performance.

• Journal of Oral Medicine and Pain
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• v.11 no.1
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• pp.19-27
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• 1986

Registration of the mandibular movement in patients with temporomandibular joint noise (clicking and/or crepitus) was performed using one of mandibular tracking devices(SAPHON VISI-TRAINER CII,Tokyo Shizai-sha Inc.,Japan). The obtained results were follows : 1. In many cases, the movement pattern of light emitting diode(LED) attached on the mandibular midline showed lateral deviation from a vertical reference line which was pronounced in association with TMJ noise during opening and closing. 2. In patients with unilateral TMJ noise the mandibular midline usually towards the side demonstrating TMJ noise during opening. 3. A distinct V-shaped discontinuity in the trace of velocity of mandibular movement was found at the point of the TMJ noise. 4. In patients with TMJ noise the velocity of mandibular movement at the point of the TMJ noise was decreased rapidly. 5. In several cases, TMJ noise could be eliminated by traning of Rocabado`s control of TMJ rotations.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.91-97
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• 2007

The purpose of this study was to investigate the changes of various balls velocity under the different surface conditions after impact. For this study, four different balls were used which are golf ball, tang-tang ball, table tennis ball, and iron ball. And two different types of ground conditions were used which are artificial grass green and glass green. Movements of putter head and ball were recorded with 2 HD video cameras(60 Hz, 1/500s shutter speed). Small size control object($18.5cm{\times}18.5cm{\times}78.5cm$) was used in this study. To transfer the same amount of kinetic energy to the ball, pendulum putting machine was used. Analyzing the process of impact and the ball movement, a putter was digitized the whole movement but the ball was digizited within the 50cm movement. Velocities were calculated by the first central difference method(Hamill & Knutzen, 1995). Putter head velocities were about 112.2cm/s-116.2cm/s at impact. Maximum ball velocities were appeared 0.08s-0.10s after impact no matter what the ground conditions are. Table tennis ball recorded higher ball velocities than the other ball velocities and iron ball recorded the lowest ball velocity in this group. But Table tennis ball was influenced with the frictional force and immediately was decreased at the artificial grass green condition. If an object is received the kinetic energy under the static condition(v=0cm/s), the object recorded the maximum velocity shortly after the impact and then decreased the velocity because of the frictional force. The ball distance from the start position to the peak velocity position is about 6cm-10cm under the 112.2cm/s-116.2cm/s putting velocity with putter. 0.25 seconds later after impact balls were placed 40cm distance from the original position except iron ball. In this study, ball moving distances were too short therefore it was not possible to investigate the reactions after the translational force is disappeared. Rotational force would play a major role at the end of the ball movement. Future study must accept two things. One is long distance movement of ball and the other is balanced ground. Three-piece ball is a good item to investigate the golf ball movement on the different surface conditions.

• Annals of Clinical Neurophysiology
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• v.1 no.1
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• pp.47-54
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• 1999

The Doppler in neurosonologic examination could be applied to blood flow to determine its movement, the direction of its movement, and how fast it is. Indicies of the Doppler study denoted velocity, direction, and amount of RBC in the examined vessel. Systolic. diastolic, and mean blood flow velocities represent velocity of RBCs in a sample volume. Blood flow direction to the probe means direction of RBC to the probe. Size of amplitude displays toe amount of the RBCs passing the sample volume. Spectral broadening means presence of turbelence. The RBC movements and hemodynamics at the examined vessels can be estimated by analysis of Doppler indicies The formation and meaning of each of neurosonologic Doppler study is described in the present review.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.23-27
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• 2011

This study analyzes about the variation of pressure and stream velocity according to the movement of tail wing. The pressure at the front part of airplane becomes lower than at the rear part and the stream velocity has decreased by being bumped against the wing of airplane. The pressure at the front part of rudder becomes higher than at its rear part according to the movement of rudder among the tail wings of airplane. The more stream velocity becomes decreased, the more rudder spreads out. As the tail wing of airplane folds, the pressure at its front part becomes higher. And the pressure at its rear part becomes lower than at its front part. The more tail wing of airplane folds, the more stream velocity becomes decreased.

• Journal of Korea Multimedia Society
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• v.22 no.1
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• pp.110-116
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• 2019

Virtual reality (VR) sickness can have an influential effect on the viewing quality of VR 3D contents. Particularly, watching the 3D contents on a head-mounted display (HMD) could cause some severe level of visual discomfort. Despite the importance of assessing the VR sickness, most of the recent studies have focused on unveiling the reason of inducing VR sickness. In this paper, we subjectively measure the level of VR sickness induced in the viewing of omnidirectional 3D graphics contents in HMD environment. Apart from that, we propose an objective assessment model that estimates the level of induced VR sickness by calculating the difference between head movement velocity and global camera motion velocity.

• Journal of Biomedical Engineering Research
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• v.30 no.2
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• pp.142-146
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• 2009

The purpose of this study is to investigate the angular velocity of forearm pronation/supination movement in Parkinson's disease patients, as a quantitative measure of the bradykinesia. Thirteen Parkinson's disease patients ($64{\pm}11.0$ yrs, male:6, female:7) participated in the experiments. The subjects' both right and left forearms were scored by a rater according to rapid alternating movement of hands category in the UPDRS (unified Parkinson's disease rating scale) and the angular velocity of forearm pronation/supination was measured at the same time. As analysis parameters, RMS (root mean square) angular velocity and RMS angle were used. The parameters showed negative correlation with the clinical score (RMS angular velocity: r= - 0.914, RMS angle: r= -0.749). The RMS angular velocity of all clinical scales were significantly different one another except for the non significant difference between those of scale 3 and 4. RMS angle of scale 0 was significantly different from those of scale 2, 3, 4 and that of scale 1 was significantly different from those of scale 3 and 4. This suggests that RMS angular velocity can be used for a quantitative measure of bradykinesia in motor examination.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.337-345
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• 2009

The purpose of this study were to find out the differences in kinematic variables of racket movement by performing the tennis serve. Three top male tennis players participated in this study. Three synchronized high-speed cameras were used to record the service action of top players for Three dimensional video analysis. The results of this study showed that (1) the velocity of the tennis racket at impact is important to the generation of racket velocity to Y-axis. This result indicates that forward motion and upward movement of the racket; (2) with respect to racket angular velocity at impact, the fast angular momentum of X-axis is important to generate the velocity of the tennis ball. This result indicate upward movement of the racket with a strong flexor of wrist joint; (3) the velocity of the tennis ball was influenced by the change of angular linking the Z-axis to -X-axis. This result indicates that the high velocity of the tennis ball is obtained from having the racket unitedly moving to the direction of the bill's flight at the acceleration interval and acquiring the distance of acceleration with the racket head vertically to the ground at the back scratching.