• Korean Journal of Applied Biomechanics
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• v.34 no.2
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• pp.81-92
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• 2024

Objective: The purpose of this study was to analyze the impact acceleration, shock attenuation and biomechanical variables at various running speed. Method: 20 subjects (height: 176.15 ± 0.63 cm, weight: 70.95 ± 9.77 kg, age: 27.00 ± 4.65 yrs.) participated in this study. The subjects ran at four different speeds (2.5 m/s, 3.0 m/s, 3.5 m/s, 4.0 m/s). Three-dimensional accelerometers were attached to the distal tibia, sternum and head. Gait parameters, biomechanical variables (lower extremity joint angle, moment, power and ground reaction force) and acceleration variables (impact acceleration, shock attenuation) were calculated during the stance phase of the running. Repeated measures ANOVA was used with an alpha level of .05. Results: In gait parameters, decreased stance time, increasing stride length and stride frequency with increasing running speed. And at swing time 2.5 m/s and 4.0 m/s was decreased compared to 3.0 m/s and 3.5 m/s. Biomechanical variables statistically increased with increasing running speed except knee joint ROM, maximum ankle dorsiflexion moment, and maximum hip flexion moment. In acceleration variables as the running speed increased (2.5 m/s to 4.0 m/s), the impact acceleration on the distal tibia increased by more than twice, while the sternum and head increased by approximately 1.1 and 1.2 times, respectively. And shock attenuation (tibia to head) increased as the running speed increased. Conclusion: When running speed increases, the magnitude and increasing rate of sternum and head acceleration are lower compared to the proximal tibia, while shock attenuation increases. This suggests that limiting trunk movement and increasing lower limb movement effectively reduce impact from increased shock. However, to fully understand the body's mechanism for reducing shock, further studies are needed with accelerometers attached to more segments to examine their relationship with kinematic variables.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.684-689
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• 2007

The aim of this study is to examine the change of the osteoclastic activity in the surrounding bone with or without tooth movement after corticotomy by histologic study. Eighteen male Sprague Dawley rats with an average body weight of 300 g(range 250-350 g) were used. The rats were divided into three groups of six animals. They were operated corticotomy-assisted tooth movement and killed after 1 week, 2 weeks, and 3 weeks after tooth movement. Corticotomy was done in the surrounding of the both upper first molar. A split mouth design was used by referring to the contralateral side as control. After flap suturing, the upper left first molar was moved anteriorly by closed coil spring. The force applied was 1 N. The average of tooth movement of the 1 week group was $0.24{\pm}0.09mm,\;0.20{\pm}0.26mm$ in 2 weeks group and $0.41{\pm}0.39mm$ in 3 weeks group, respectively. The difference between the 1 week and the 2 weeks groups was very small to compare with the 3 weeks group. In the treatment group, the average numbers of cells that positively reacted to TRAP were 14.5 in the 1 week group, 12.0 in the 2 weeks group, and 6.0 in the 3 weeks group. In the control group, the numbers were 8.3 in the 1 week group, 12.8 in the 2 week group, and 1.5 in the 3 week group, respectively. The amount of tooth movement of the 3 week group was about twice as large as those of the 1 week and 2 week groups. From the standpoint of histology, the average number of cells that positively reacted to TRAP was initially larger in the treatment group than in the control group, similar in both group in 2 weeks, and became less in the treatment group in 3 weeks. Additionally, in the control group, their activity of osteoclast was higher in 2 weeks than in 1 week, and decreased rapidly in 3 weeks.

• Korean Journal of Ecology and Environment
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• v.48 no.2
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• pp.77-85
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• 2015

Siniperca scherzeri is major target species for restocking and restoration project as it is one of the economic species in South Korea. In this study, to investigate their ecological characteristics movement pattern and habitat characteristic of S. scherzeri were analyzed using radio telemetry. Three specimens released during spawning season, moved more than 10 km toward upstream from the release site. Whereas the remains released after spawning season, settled within 400 m of their release site except two specimens (Ss 11, 3.2 km; Ss, 15, 1.4 km). One of possible reason of upstream movement during spawning season is reproduction. The conditions of their settlement area is similar with reference conditions of their spawning ground. S. scherzeri were mainly detected near the edge of the water, and it may related with the facts that rocks are mainly located at the edge of the water and S. scherzeri prefers rocks for their shelter. AMD (Accumulated movement distance) positively related with body weight and condition factor K, but no significant relationship was identified with gender and total length. Daily movement boundary of S. scherzeri was $214.94m^2{\sim}3,257.19m^2$, and their movement was restricted near the edge of the water. The results of this study could be useful to restocking and restoration.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.33-49
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• 2002

This study was intended to provide basic materials for golf coaching by somatotype by analyzing and comparing the kinematic factors found in each somatotype at the time of golf swing. For this purpose, the somatotype was divided into endomorph, mesomorph and ectomorph in reference to the weight, height and upper arm circumference of each of nine professional golfers. Each of their swing motions was videotaped with the camcorder and their swing motion was analyzed by dividing it into 8 sections. The time required for the swing motion, the displacement of the center of the human body and the rotation angle of the upper body were calculated through the three-dimensional image analysis based on the DLT(Direct Linear Transformation). Based on the findings of this study, the following conclusion was drawn: The endomorphic golfers showed the longest required golf swing time, followed by the mesomorphic golfer and then the endomorphic golfer. The displacement of left-to-right movement was largest in the mesomorphic golfers, followed by the endomorphic golfers the up-to-down displacement was upward at the time of impact and that the endomorphic and mesomorphic golfers raised the sense of stability by maintaining an almost uniform height at the time of impact. As for the rotational angle of the upper body and the rotational angle of the thigh, the upper body and the thigh took a form of rotating earlier in the ectomorphic golfers at the time of impact, who showed a somewhat different characteristics compared to the endomorphic and mesomorphic golfers. It is necessary to investigate the movement of more fundamental forces in presenting the theory related to the kinematic characteristics of this swing by somatotype. Accordingly, it is thought that it is necessary to analyze the center of pressure(COP) using the ground counterforce in the future study.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.155-164
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• 2007

This study is to find out effective defensive type by analysis on differences among three different defence types of the body lock technique in the ground wrestling. The subjects are 5 athletes who are in 60kg weight class. To get the kinematic analysis seven ProReflex MCU-240(Motion Capture Unit), infrared rays cameras, which was produced by Qualisys, were used to get a two-dimensional coordinate. Following are the analysis result from kinematic factors such as time element, speed element and angular element. 1. During position of ground wrestling, the average necessary time until defender's hip joint touches the mat for Phase1 was $0.34{\pm}0.14sec$ at side position was the shortest space of time out of three types, and Phase2 was $0.21{\pm}0.02sec$ at front position was the shortest space of time out of three types. Moreover, side defence position was the shortest for total average necessary time with $0.78{\pm}0.05sec$. 2. The movement change for hip joint was $57.21{\pm}20.17cm$ for front, $43.35{\pm}7.13cm$ for rear, and $18.67{\pm}10.24cm$ for side at Phase1 and $42.08{\pm}17.56cm$ for side, $16.61{\pm}6.34cm$ for front, and $1.48{\pm}1.29cm$ for rear at Phase2. 3. Movement speed of hip joint at defensive type were most effective in success and fail rate at Phase 1 and its frontal average speed was fastest with $1.01{\pm}0.23m/s$ following by $0.52{\pm}0.15m/s$ for side, and $0.62{\pm}0.15m/s$ for rear. The average for total change of speed is $0.79{\pm}0.32m/s$ for front, $0.78{\pm}0.17m/s$ for side, and $0.49{\pm}0.08m/s$ for rear. 4. The joint angle gets smaller in a order by rear, front, and side for the size of hip joint angle and knee angle for different defensive type. 5. As a result of one-way ANOVA on linear velocity for hip joint in frontal defence(phase1) was significance ($\alpha$=.05), but phase 2 was not significance. Synthetically, analyzing on differences among three different defence types which were front, rear, and side of the body lock technique in the ground wrestling, front defensive type was the most effective. In future, there should be more studies regarding on defence at not a laboratory study but a field study to help out wrestler to pertinent techniques to improve the game of wrestling.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.201-209
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• 2015

The deformed degree of car body varies largely with the collision part from side collision of car-to-car. In case of deformation of car body caused by collision, the movement is different as speed energy changes to strain energy. Generally, in the analysis of traffic accident, the movement of car after the collision is analyzed by law of conservation of motion and the error of energy absorption rate along the deformation of car body can be calibrated by inputting coefficient of restitution, but it is current situation that coefficient of restitution applied by referring to the research results of forward collision and backward collision because the research results of side collision is rare. Vehicle model of finite element method applied by structure of car body and materials of each component was analyzed by explicit finite element method, and coefficient of restitution and collision detection time along contact part of side collision was drawn by analyzing the results. Analysis result acquired through the law of conservation momentum by applying finally-computed coefficient of restitution and crash detection time compared to collision result of actual vehicle. As a result, the reliability of analysis was higher than the existing analysis method were acquired when applying the drawn initial input value that used finite element method analysis model.

• Journal of the Korean Society of Costume
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• v.63 no.4
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• pp.84-100
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• 2013

Ancient Greece was a patriarchal society that distinguished gender roles between men and women. Although their costumes were composed of simple rectangular fabric without any technical complications in itself, the Greeks did try to express gender differences in their clothing. The final look of the Greek costume was dependent on the way the cloth draped onto its wearer as well as the wearer's identity. Greeks costume could just be seen as a rectangular fabric when it was not draped on a person's body. The purpose of this study is to examine how the gender differences were expressed in the ancient Greek drapery costume, which was made by using a completely different technical process, compared with the modern tailored costume. There are four elements of the costume that give the costume its formative shape, which are the wearer's body, the rectangular fabric (material as the first formative costume), the way the fabric is draped, and the final appearance as the second formative costume (the relationship between the wearer's body and the costume) and this study analyzes these elements individually. It is intended to analyze the gender characteristics and how each element appears in a different way from the perspective of Structuralism, an analytical method that considers a phenomenon as a total sum of the elements. Literature research was conducted and representative sculpture, painting and pottery, were used between the Archaic Period (B.C. 800~500) and the Classical Period (B.C. 500~323). The results show that the gender differences appear in each formative element of costume: First, the body was distinguished by the ancient Greek custom. The man's nudity was accepted while the woman's body was concealed. Second, in regards to the first formative costume, which was the rectangular fabric, men's were made with thick high quality wool because their involvement in outdoor activities meant that they needed clothes to stay warm, while the women wore clothes made of thin wool or hemp cloth, because their most of their activities were at home. Third, the way to drape the fabric shows the gender differences by changing the length of the clothing and its design ; men's short khiton was practical for big movement and at the same time the clothing exposed the man's body. The woman's doric khiton diversified its decoration by the size of the apotigma and by using the belt. Finally the second formative costume reflected the Greeks' social distinction between a man's body and a woman's body. The man's costume naturally exposed the man's body. On the other hand, the woman's long costume has a variety of shapes on the ground, that concealed her lower body, while the ornamental function was more accentuated than the man's costume. The gender differences expressed in Greek costume fundamentally reflected the point of view of the male and female body and their social roles in society.

• PNF and Movement
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• v.6 no.2
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• pp.1-10
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• 2008

Purpose : The purpose of this study was to investigate the effect of aquatic exercise applied PNF patterns on body composition and balance performance in people who have had a stroke. Methods : Forteen candidates who have all experienced a stroke were participating in a community based rehabilitation program, have been included in this study. The program was conducted three times weekly, 1 hour per session, for 10 consecutive weeks. Subjects were tested with body composition and 5 items of Berg's balance test at pre-training and post-training. Total balance indexes in 3 conditions were measured by K.A.T. 3000. The aquatic exercise applied PNF patterns was consisted of PNF patterns and various aquatic activities. Results : After ten weekends of aquatic exercise training, there were not significant difference in body composition(p>.05) except of muscular weight of affected lower extremity(p<.05). But edema index increased more than pre-training (p<.05). Subjects showed significant difference in Berg's balance test results except of 2 items of Berg's balance test (p<.05). Total balance index score when subjects opened their eyes and didn't hold the handle was decreased less than pre-training(p<.05). Conclusion : The results of this study showed that intervention of this aquatic exercise program applied PNF patterns could increase edema index and muscular weight of affected lower extremity and improve the balance performance in people who have had a stroke.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.8 s.99
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• pp.790-796
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• 2005

In order to accomplish a wireless communication of capsule endoscopy, an environment study in the human body and receiving antenna design have been performed. The proposed antenna is the loop antenna designed to minimize the propagation loss in multi-loss layer such as the human body and utilize the magnetic field. Considering the propagation loss in the human body, the frequency range is from 400 MHz to 500 MHz. Acorrrding to the FCC regulations, the permittivity and conductivity for each human tissue were extracted. We set up an equivalent model and make an aqueous solution which is replaced with the human body. Due to movement of capsule in the human body which propagation loss is extremly severe, an array antenna is required. Irrespective of the location of transmission antenna transmitting a signal of 1 mW, we confirme what it is possible for the enough signal detection as the average signal level of array antenna is -60 dBm.

• Korean Journal of Applied Biomechanics
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• v.15 no.2
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• pp.129-138
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• 2005

The purpose of this study was to investigate the techniques used by long jumpers who recorded over 8meters in 2002 Busan Asian Game and 2003 Daegu Universiade. The kinematic characteristics from the last three stride to takeoff at the takeoff board were analyzed such as velocities, heights and angles. The real-life three-dimensional coordinates of 20 body landmarks during each trial were collected using a Direct Linear Transformation procedure. The conclusion were as follows; 1. The height variation who recorded over 8 meters of center of gravity of the jumpers at the last stride was under 8cm. In order to record over 8meters the national long jumpers should have under 10cm height variation. 2. In the approach phase the horizontal velocity of the jumpers should reach to 10.5m/s in last three strides and 9.79m/s in touch down at take off board. 3. The horizontal velocity at take off board must have over 8.51m/s and the vertical velocity must have 3.75m/s simultaneously in order to record 8meters. 4. The forward body lean angle should have over 20degrees with pushing the take off board in forwarding movement. The appropriate body variation range ratio between take off and touch down should be 1.2 vs 1 and the trunk angle at touch down on the board should be close to the erect posture for higher body flight.