• 한국전문물리치료학회지
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• 제24권4호
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• pp.11-19
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• 2017

Background: Methods for exercising serratus anterior (SA) and upper trapezius (UT) muscles are important for the recovery of patients with various shoulder disorders, yet the efficacy of closed or open kinetic chain exercises have not yet been evaluated. Objects: The purpose of this study was to compare the activation of the SA and UT muscles during scapular protraction considering both closed and open kinetic chain exercises. Methods: Thirty subjects were randomly divided into experimental groups (closed kinetic chain exercise) and control groups (open kinetic chain exercise) in which scapular protraction was performed at $90^{\circ}$ or $125^{\circ}$ shoulder flexion. Electromyographic activity data were collected from the SA and UT muscles per position and exercise method. Results: Separate mixed 2-way analysis of variance showed significant differences in the activation of the SA (F1,28=6.447, p=.017) and the UT (F1,28=35.450, p=.001) muscles between the groups at $90^{\circ}$ and $125^{\circ}$ shoulder flexion. Also, the SA/UT ratio measures at $90^{\circ}$ and $125^{\circ}$ shoulder flexion significantly differed between the groups (F1,28=15.457, p=.001). That is, the closed chain exercise was more effective than open chain exercise for strengthening the SA muscle and controlling the UT muscle, $125^{\circ}$ of shoulder joint was more effective than $90^{\circ}$. Conclusion: The findings suggest that scapular protraction with shoulder $125^{\circ}$ flexion at the closed kinetic chain exercise may be more effective in increasing SA muscle activation and decreasing UT muscle activation as well as increasing the SA/UT ratio than open kinetic chain exercise.

• 대한통합의학회지
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• 제5권3호
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• pp.49-55
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• 2017

Purpose: The purpose of this study was to investigate effect of open kinetic chain exercise on the motor function of the lower limb in middle school soccer players. Method: The subjects consisted of 14 soccer players who attend middle school in Gwangju. All subjects received open kinetic chain exercise for 3 weeks. The muscle strength of the ankle was measured by a commander muscle tester. Postural control ability was measured using a hopping test. All measurements for each subject were conducted pre-intervention and 3 weeks post-intervention. Result: There were significant differences post-intervention in the muscle strength and-the postural control ability of the open kinetic chain exercise group(p<.05). Conclusion: Open kinetic chain exercise had a significant positive effect on the motor function of the lower limb in soccer players. Therefore, open kinetic chain exercise may prevent and resolve injury with careful management while soccer players are training or playing games. It could be helpful to extend the lives of athletes and improve their records.

• 한국정밀공학회지
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• 제11권5호
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• pp.88-97
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• 1994

We persent a method for kinematic calibration of open chain mechanisms based on the product of exponentials (POE) formula. The POE formula represents the forward kinematics of an open chain as a product of matrix exponentials, and is based on a modern geometric interpretation of classical screw theory. Unlike the kinematic parameters in the POE formula vary smoothly with changes in the joint axes;ad hoc methods designed to address the inherent singularities in the D-H parameters are therefore are therefore unnecessary. After introducing the POE formula, we derive a least-squares kinematic calibration algorithm for general open chain mechanisms. Simulation results with a 6-axis open chain are presented.

• 대한물리의학회지
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• 제8권3호
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• pp.369-378
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• 2013

PURPOSE: The purpose of present study was to ascertain how the activity of the serratus anterior muscle, the upper trapezius muscle and the pectoral major muscle was affected while the upper arm was being flexed at 70, 90 and 110 degrees respectively in a closed kinetic chain exercise (wall push up plus) and an open kinetic chain exercise (static hug). METHODS: Sixteen healthy young men subjects participated in the study. Surface electromyography (EMG) data were collected from the dominant-side muscles during a closed kinetic chain exercise and an open kinetic chain exercise. The activity of each muscle was measured quantitatively, and by the use of the two-way repeated ANOVA, the data were compared with each other according to exercises and shoulder flexion angles. RESULTS: Results indicated that the closed kinetic chain exercise did not interact with the open kinetic chain exercise (p>.05). In both the closed kinetic chain exercise and the open kinetic chain exercise, the activity of the serratus anterior muscle became different significantly according to angles (p<.05). Its activity increased in order of 70, 90 and 110 degrees (p<.05). In both exercises and all angles, muscle activity was significantly higher in the serratus anterior muscle than in the upper trapezius muscle and the pectoral major muscle (p<.05). CONCLUSION: The above results show that there is a need to selectively control the exercise stress of the serratus anterior muscle in the case of the patients with the shoulder impingement syndrome characterized by the winged scapula, insufficient scapular protraction and upward rotation.

• 대한예방한의학회지
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• 제12권3호
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• pp.115-128
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• 2008

Purpose : This study was performed to distinguish the muscle activation of vastus medialis and biceps femoris through open and closed kinetic chain exercise. Methods : 31 healthy male and female students in Daegu Health College were participated in this study. All subjects were conducted three types open and closed kinetic chain exercises to examine muscle activity during the last four seconds using the sEMG system. Collected EMG data were normalized using the maximal voluntary isometric contraction(MVIC). Results : MVIC of each muscle was showed significantly increased(p<0.5). In the case of open chain exercise, the type 3 exercise most increased than type 2 and 3 exercise in vastus medialis than biceps femoris muscle. The closed chain exercise presented type 6 exercise most increased than type 4 and 5 exercise in biceps femoris than vastus medialis. Conclusion : This study finally proved that muscle activity which maintains stability of knee differ from depending on the types of exercises. Therefore, the combination of the two chain exercises is believed to greatly contribute to increments in muscle activity.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제8권2호
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• pp.75-86
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• 2004

In this study, a recursive algorithm for generating the equations of motion of a chain of rigid rods is presented. The methods rests upon the idea of replacing the rigid body by a dynamically equivalent constrained system of particles. The concepts of linear and angular momentums are used to generate the rigid body equations of motion without either introducing any rotational coordinates or the corresponding transformation matrices. For open-chain, the equations of motion are generated recursively along the serial chains. For closed-chain, the system is transformed to open-chain by cutting suitable kinematic joints with the addition of cut-joints kinematic constraints. An example of a closed-chain of rigid rods is chosen to demonstrate the generality and simplicity of the proposed method.

• 대한기계학회논문집A
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• 제20권1호
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• pp.35-43
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• 1996

A computer program for automatic deriving the symbolic equations of motion for robots using the programming language MATHEMATICA has been developed. The program, developed based on the Lagrange formalism, is applicable to the closed chain robots as well as the open chain robots. The closed chains are virtually cut open, and the kinematics and dynamics of the virtual open chain robot are analyzed. The constraints are applied to the virtually cut joints. As a result, the spatial closed chain robot can be considered as a tree structured open chain robot with kinematic constraints. The topology of tree structured open chain robot is described by a FATHER array. The FATHER array of a link indicates the link that is connected in the direction of base link. The constraints are represented by Lagrange multipliers. The parallel robot, DELTA, having three-dimensional closed chains is modeled and simulated to illustrate the approach.

• 대한물리의학회지
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• 제4권2호
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• pp.93-100
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• 2009

Purpose：The purpose of this study was to examine the effects of self-controlled knowledge of result (KR) versus the yoked KR on learning of knee joint proprioception. Methods：Forty volunteer subjects (20 men and 20 women) were randomly assigned to each four groups: 1) self-controlled KR in open kinematic chain, 2) yoked KR in open kinematic chain, 3) self controlled KR in close kinematic chain, and 4) yoked KR in close kinematic chain. The difference between the angle of position and reproduction angle was determined as a proprioception error and measured using an angle reproduction test. The subjects in self-controlled groups were provided with feedback whenever they requested it, whereas the subjects in yoked groups were not provided with feedback. The data were analyzed using a one-way ANOVA. Results：The proprioception errors in close kinematic chain groups decreased significantly compared with those in close kinematic chain groups(p<.05). The proprioception errors in the self-controlled group decreased significantly compared with those in yoked groups during acquisition and retention test(p<.05). Conclusion：Self-controlled knowledge of result during open kinematic chain movement is considered to be a good method on motor learning.

• ETRI Journal
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• 제46권1호
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• pp.11-21
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• 2024

We focus on open-domain question-answering tasks that involve a chain-of-reasoning, which are primarily implemented using large language models. With an emphasis on cost-effectiveness, we designed EffiChainQA, an architecture centered on the use of small language models. We employed a retrieval-based language model to address the limitations of large language models, such as the hallucination issue and the lack of updated knowledge. To enhance reasoning capabilities, we introduced a question decomposer that leverages a generative language model and serves as a key component in the chain-of-reasoning process. To generate training data for our question decomposer, we leveraged ChatGPT, which is known for its data augmentation ability. Comprehensive experiments were conducted using the HotpotQA dataset. Our method outperformed several established approaches, including the Chain-of-Thoughts approach, which is based on large language models. Moreover, our results are on par with those of state-of-the-art Retrieve-then-Read methods that utilize large language models.

• Archives of Pharmacal Research
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• 제26권12호
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• pp.990-996
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• 2003

A novel carboacyclic nucleoside analogue, 9-[2-bromo-4-hydroxy-3-hydroxymethyl-2-butenyl] adenine, and its derivatives were designed and synthesized as open-chain analogues of neplanocin A. The syntheses were accomplished via the coupling of adenine or pyrimidine bases to the key intermediate allylic bromide 7. The bromide 7 was prepared from epichlorohydrin in a seven step process in a 54% overall yield. The synthesized compounds were evaluated for their antiviral activity against the polio virus, HSV and HIV.