• Korean Journal of Ecology and Environment
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• v.55 no.3
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• pp.251-257
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• 2022

Monitoring and assessing aquatic ecosystems using the behavior of organisms is essential for sustainable ecosystem management. Oligochaetes, which inhabit various freshwater ecosystems, are frequently used to evaluate the environmental conditions of freshwater ecosystems. Tubifex tubifex (Müller, 1774) (Oligochaeta, Tubificidae) is tolerant to organic pollution and has been used to evaluate the toxicity of toxicants, including heavy metals. We studied the behavioral responses of T. tubifex to three different copper concentrations (0.1, 0.5, and 1.0 mg L^-1). The specimens were exposed to copper in an observation cage containing 150 mL of dechlorinated water. Movement behavior (diameter, speed, acceleration, meander, and turning rate) was continuously observed for two hours before and after the copper treatments. After the treatments, the diameter shrank and showed rapid twisting movement under all the copper conditions. The turning rate had a positive correlation with meander and acceleration both before and after treatment at all three concentrations, whereas speed and meander had a negative correlation. Length and turning rate also showed a negative correlation. The correlation coefficient between speed and acceleration in the highest copper concentration changed from positive before treatment (r=0.64) to negative (r= -0.52) after treatment. Our results present the possibility of using behavioral parameters to detect copper contamination in freshwater ecosystems.

• Korean Journal of Applied Biomechanics
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• v.14 no.2
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• pp.41-55
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• 2004

This study analyzed snatch technique in weight-lifting performed by female gold, silver, and copper medalists at the 75kg level in the 2002 Pusan Asian Games and obtained the following conclusions. 1. KSH used more extensor in the waist than those in ankles, knees, or hip joints during the second pull, So further training is required to manifest both each of joints and waist extensor effectively and thus for the line from shoulders through barbell to hip joints to form a smooth vertical pattern. 2. Contrary to those in other countries, Korean athlete KSH tended to be swift in starting but slow in the second pull section, showing less effectiveness in movement during the second pull; therefore, they must try to exert a swift movement in lockout. 3. KSH showed slowdown in the speed, which was a factor interfering with performance during second pull, despite the great maximum speed of moving barbell. It is important to use barbell sufficiently not to reduce the speed of vertical movement but rather to keep the speed increasing. 4. KSH, who kept doing inefficient movements such as failure to perform swift lockout after lifting the heel at the maximum angle of lower limbs, needs to reduce this meaningless extension of ankles, knees, or hip joints to exert energy effectively.

• 한국해양학회지
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• v.8 no.1
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• pp.46-52
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• 1973

From available data, the movement of the cold water in the Korea Strait was investigated. The cold water forms an undercurrent with a speed of 0.10knots near Ulgi in June. Sometimes it reaches a speed of 0.35knots. The cold water forms a sharp wdege in the western channel like a salt wedge in an estuary. The calculated volume transport of the cold water is 17,135 cubic meters per second in June. The external influences are also discussed.

• The Research Journal of the Costume Culture
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• v.21 no.1
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• pp.81-92
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• 2013

Many women feel pain in their breasts while running due to an excessively large degree of breast movement. Therefore, most sports bras pursue a reduction in breast movement. The purpose of this study is to investigate the breast movement reduction effect of a selection of sports bra designs according to the intensity of the sport and the breast size of the wearer. The study measured differences in the vertical movement of the nipple with 4 types of sports bras and 3 exercise speeds(4km/h, 7km/h, and 10km/h). Subjects included women in their 20s with bra sizes of either B cup(n=3) or C cup(n=3). The results of the study are as follows. Breast movement differed according to running speed and breast size; breast movement significantly increased starting with jogging speed(7km/h), and the C-cup group had a larger degree of vertical movement than the B-cup group. A superior effect on breast movement during jogging(7km/h) and sprinting(10km/h) was observed differently by bra cup sizes. To C-cup group, encapsulation-style sports bra, which provides horizontal support across the upper breast and padding inside the shoulder strap and bra cup to ease impact was most effective and next effective style was the compression-style bra with a princess line to cover the breasts solidly. Most style sports bra were effective in the B-cup group. Besides aforementioned encapsulation-style sports bra, the compression-style bra with a band, which presses the breasts against the chest wall, reduced breast movement effectively.

• Fisheries and Aquatic Sciences
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• v.8 no.3
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• pp.177-181
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• 2005

Fishing selectivity is determined by the level of voluntary escaping behavior in accordance with decision-making based on the relationship between fish size and mesh size. This study examined movement during the swimming behavior of black porgy in a trawl's towing cod-end and analyzed the movement components such as swimming speed, angular velocity of turning, and distance to the net over time. Most of the observed fish exhibited an optomotor response, maintaining position and swimming speed without changing direction. Others exhibited erratic or 'panic' behavior with sudden changes in swimming speed and direction. The latter behavior involved very irregular and aperiodic variations in swimming speed and angular velocity, termed 'chaotic behavior.' Thus, the results of this study can be applied to a chaotic behavior model as a time series of swimming movements in the towing cod-end for the fishing selectivity.

• Korean Journal of Applied Biomechanics
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• v.24 no.3
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• pp.229-238
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• 2014

This study comparatively analyzed the speed and segment coordination characteristics of Taekwondo hand techniques, while different attention focusing strategies were utilized. Ten elite Taekwondo poomsae athletes participated, and three different strategies (no focus, target focus, body focus) were utilized in random order. The hand velocity and upper body segment coordination characteristics were analyzed, with the following results. First, the maximum magnitudes of the hand velocity differed between the focus conditions for the Araenaereomakgi and Momtongjireugi techniques. Second, the angular velocity and kinetic energy transfer patterns of the segments differed between the focus conditions, and in the case of the body focus condition, the movement was more correct according to the theory. Third, the shoulder and elbow joint coordination patterns differed between the focus conditions, with more efficient movement shown with the body focus condition. In conclusion, we confirmed the potential of effectively using an attention focusing strategy in a taekwondo teaching situation. However, the effect on the movement coordination and results of the movement could be changed by a difference in the cue provided or the type of the task. In addition, depending on the task, the attention focusing strategy could affect the efficiency of the movement. Therefore, coaches and masters of Taekwondo will have to constitute determine the appropriate attention focusing cues based on the task.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.119-120
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• 2010

• PNF and Movement
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• v.16 no.1
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• pp.27-32
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• 2018

Purpose: This study examined changes in gait speed and stride length after an intervention involving simultaneous scapular and pelvic patterns of proprioceptive neuromuscular facilitation in a hemiplegic patient. Methods: A 58-year-old woman with left hemiplegia who had complained of slowness of gait speed and weakness of leg strength took part in an intervention involving scapular postdepression patterns on the affected side and pelvic postdepression patterns on the nonaffected side. The intervention was performed with the patient lying on her left side, in a half kneeling position, and in a standing posture. Rhythmic initiation was used for teaching the movements to the patient and improvement of kinesthesia, and a combination of isotonic was employed for increasing strength and irradiation of the scapula and pelvic movement. The intervention took place for 30 min. It was implemented twice a day, 5 days a week, for 3 weeks. After three repetitions, the average time taken to complete the 10-m walk test (10 MWT), in addition to stride length, was measured to determine gait speed. Results: After the 3-week program, the patient's performance in the 10 MWT improved from 21.7sec to 17.1sec, and her stride length improved from 31.4cm to 38.7cm. Conclusion: The results showed that trunk movement exercise, especially coordinative movements of the scapula and pelvis can improve gait speed and stride length by increasing trunk stability and mobility. A combination of pelvic and scapular patterns can facilitate trunk rotation, thereby improving gait speed and stride length.

• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.167-174
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• 2011

This paper proposed a smart-phone based user movement state identification algorithm. Then movement state of the user is identified by calculating the location and moving speed using the GPS sensor, and detailed movement methods are identified by analyzing the data from the Orientation sensor. In this study, two sensors of the smart-phone were used to implement the user movement status identification algorithm and to perform tests. The reference values of the speed and orientation required for the identification of the movement type were defined based on the experimental data. The results of this study showed that the movement type of a smart-phone user can be identified using the user movement state identification algorithm.

• The korean journal of orthodontics
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• v.51 no.6
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• pp.366-374
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• 2021

Objective: This study investigated the impact of a single piezocision in the maxillary alveolar process on the speed of tooth movement. The null hypothesis was that the speed of tooth movement will be equal with and without piezocision. Methods: All maxillary molars on one side were moved against the combined incisors in 10 ten-week-old male Wistar rats. Under general anesthesia, a force of 25 cN was applied on either side using a Sentalloy closed coil spring. After placing the orthodontic appliance, vertical corticision was performed using a piezotome under local anesthesia, 2 mm mesial from the mesial root of the first molar on a randomly selected side; the other side served as the control. At the beginning of the treatment, and 2 and 4 weeks later, skull micro-computed tomography was performed. After image reconstruction, the distance between the mesial root of the first molar and the incisive canal, and the length of the mesial root of the first maxillary molar were measured. Moreover, the root resorption score was determined as described by Lu et al. Results: Significantly higher speed of tooth movement was observed on the corticision side; thus, the null hypothesis was rejected. The loss of root length and root resorption score were significantly more pronounced after piezocision than before. A strong correlation was observed between the speed of tooth movement and root resorption on the surgical side, but the control side only showed a weak correlation. Conclusions: Piezocision accelerates orthodontic tooth movement and causes increased root resorption.