• Korean Journal of Applied Biomechanics
• /
• v.28 no.3
• /
• pp.187-191
• /
• 2018

Objective: The purpose of the present study is to investigate the effect of a muscle activity by applying the complex exercise method of sling in accordance with the provision of various vibration intensities for paraplegia-spinal cord injury. Method: The subjects of the study were 15 men in their 40s and 50s with lower limb disabilities and low potential risk, who were randomly divided into a sling exercise group (SG n=4), a sling with low frequency vibration group (SLVG n=4), a sling with mid-frequency vibration group (SMVG n=4), and a sling with high frequency group (SHVG n=4) in accordance with the provision of slings and vibration stimuli. The vibratory intensity provided was divided into low frequency (30 Hz), mid-frequency (50 Hz), and high frequency (70 Hz). The anterior deltoid (AD), the posterior deltoid (PD), the pectoralis major (PM), the upper trapezius (UT), the latissimus dorsi (LD), and the multifidus (MF) were measured to compare and analyze muscle activity. Results: The closed kinetic chain (CKC) exercise to the shoulder joint showed higher muscle activity in most muscles for the SMVG, and statistically significant differences in the anterior deltoid (AD), the pectoralis major (PM), and the multifidus (MF) in particular. Conclusion: The intermediate frequency (50 Hz) string vibration was the effective vibration stimuli for Closed kinetic chain (CKC) exercises.

• Journal of The Korean Society of Integrative Medicine
• /
• v.1 no.2
• /
• pp.67-80
• /
• 2013

Purpose : This study was to investigate effects of closed kinetic chain and open kinetic chain exercise on the lumbar stabilizarion. Methods : A total of 30 healthy over 20 years old college students(men = 14, women = 16) who were participated in this. We selected randomly people of CKC, OKC, and control group. For the past four weeks, CKC and OKC group worked out 3 times per week and then we compared within group and between groups on muscle width. Results : 1. The width of internal oblique, transverse abdominis, and multifidus were all significantly increased after four weeks exercise in the CKC group(P<.05). 2. The width of internal oblique, transverse abdominis, and multifidus were all increased after four weeks exercise in the OKC group but transverse abdominis musule only showed significant difference. 3. Difference values between pre-exercise and post-exercise of transverse abdominis and multifidus in the CKC group was significantly high and difference among the groups were significant. Conclusion : Accordingly, lumbar stabilizing exercise was more effective to increase a width of abdominal deep muscles through CKC exercise.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.27 no.3
• /
• pp.89-98
• /
• 2021

Purpose: The purpose of this study was to determine the effects of electromyography (EMG)-biofeedback based closed kinetic chain exercise (CKCE) on quadriceps muscle activity and dynamic balance ability in patellofemoral pain syndrome (PFPS). Methods: Thirty subjects with PFPS were included and they were divided into EMG-biofeedback using CKCE (Group I) and squat exercise using CKCE (Group II), each group consisted of 15 patients. Group I and Group II was performed by the patients for three times a week, for six weeks. sEMG was used to measure quadriceps muscle activity and star excursion balance test (SEBT) was used to measure dynamic balance ability. Results: According to the results of the comparisons between the groups, after intervention, quadriceps muscle activity and dynamic balance ability were significantly higher in Group I than in the Group II. Conclusion: Findings of this study suggest that EMG-biofeedback using CKCE that provides real-time biofeedback information on muscle contraction may have a beneficial effect on selective muscle strength of vastus medialis oblique muscle and dynamic balance ability in PFPS.

• The korean journal of orthodontics
• /
• v.24 no.3 s.46
• /
• pp.631-648
• /
• 1994

The purpose of this study was to investigate the effects of different types of orthodontic force on the root resorption and repair in rat molar. 77 rats were divided into three groups; The control group was not equiped with orthodontic appliance between incisor and first molar. The experimental group was subdivided into closed coil spring subgroup and elastic chain subgroup by the application methods of orthodontic force. Initial orthodontic force between incisor and first molar was 100g. Experimental period was 8 weeks; for 4 weeks the appliance was acting and for another 4 weeks, removed. Root resorption and repair in the root of first molar was examined by light microscope for histologic changes and by inductively coupled plasma spectroscopy(ICP) for quantitative changes. The results were as follows: 1. In the closed coil spring subgroup odontoclasts and root resolution were appeared one week earlier. 2. One week after orthodontic force was eliminated the repair response in the resorptive lacuna was seen in both subgroups. Delayed resorption was seen on the periphery of resorptive lacunae whereas reparative response was seen in the center of lacunae. A new resorption was seen one week after orthodontic force was eliminated. Root contour was partially restored by repairing of resorbed root. 3. The weight ratios of calcium and phosphorous to the sample were decreased during resorptive process but increased during repair process in both the orthodontic groups, but not more than the control group. 4. By different types of orthodontic force (closed coil spring or elastic chain) resorption process was affected but repair process was not.

• Journal of The Korean Society of Integrative Medicine
• /
• v.3 no.1
• /
• pp.81-90
• /
• 2015

Purpose: The purpose of this study was to investigate any visible difference in shoulder stability muscle activity along the bending angle($70^{\circ}$, $90^{\circ}$, $110^{\circ}$) to perform the open kinetic chain(OKC) and closed kinetic chain(CKC) exercise. Method: This study was performed on normal 20 males subjects. Exercise was carried out in two ways OKC and CKC. Shoulder stability muscles are examined activity in the bending angles. In the OKC and CKC exercise to subjects with stretched out waist straightened, and than push forward the shoulder. Muscular activation was examined using the WEMG-8. Result: The results of this study were as follows. 1. Only in the trapezius muscle, it showed specific interaction between exercise methods and angles. When it comes to muscle activity, there was no significant difference in all muscles except for the anterior fibers of the deltoid muscle during both CKC and OKC exercise. 2. The average value of maximum muscle activity was significantly increased with increasing order of angles. But in CKC exercise, the muscle activity of infraspinatus tended to decrease with increasing angles. Conclusion: To summarize the research results, the muscle activity in upper fibers of the trapezius, anterior fibers of the deltoid, and serratus anterior was significantly different depending on the angle of the shoulder in both CKC and OKC exercise.

• The Journal of Korean Physical Therapy
• /
• v.32 no.4
• /
• pp.238-244
• /
• 2020

Purpose: This study compared the effects of the fascial distortion model (FDM), foam rolling (FR), and self-stretching (SS) on the ankle dorsiflexion range of motion (ROM). Methods: Thirty subjects who had no more than 30° of ankle dorsiflexion ROM at the weight-bearing lunge test were recruited in this study. They were divided into three groups: (FDM, FR, and SS), and underwent each intervention for five minutes. Before and after the intervention, the ankle dorsiflexion ROM in the supine (the open-) and standing (the closed-kinetic chain) of the subjects were tested. The changes in the ROM between pre- and post-intervention and among the groups were analyzed. Results: All groups showed increased ankle dorsiflexion ROM after the intervention in both positions. In the position of the open kinetic chain, the changes in the ROM between pre- and post-intervention had significant differences among the groups, and the FDM was higher than the FR and SS. In the position of the closed kinetic chain, the ROM after the interventions and the changes in the ROM had significant differences among the groups, and FDM was higher than the FR (ROM after the intervention, the change in ROM) and SS (the change in ROM). Conclusion: These findings showed that FDM had more efficiency than the FR and SS as FDM had a stronger effect on increasing ankle dorsiflexion in a short, limited time. Clinicians who have limited time to treat their patients, particularly trying to increase ankle dorsiflexion ROM, should consider the application of FDM.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.9
• /
• pp.4180-4196
• /
• 2017

In this paper, we analyze average capacity of an amplify-and-forward (AF) cooperative communication system model in multi-relay multiuser networks. In contrast to conventional cooperative networks, relays in the considered network have no embedded energy supply. They need to rely on the energy harvested from the signals broadcasted by the source for their cooperative information transmission. Based on this structure, a two-step selection scheme is proposed considering both channel state information (CSI) and battery status of relays. Assuming each relay has infinite or finite energy storage for accumulating the energy, we use the infinite or finite Markov chain to capture the evolution of relay batteries and certain simplified assumptions to reduce computational complexity of the Markov chain analysis. The approximate closed-form expressions for the average capacity of the proposed scheme are derived. All theoretical results are validated by numerical simulations. The impacts of the system parameters, such as relay or user number, energy harvesting threshold and battery size, on the capacity performance are extensively investigated. Results show that although the performance of our scheme is inferior to the optimal joint selection scheme, it is still a practical scheme because its complexity is much lower than that of the optimal scheme.

• Communications of the Korean Mathematical Society
• /
• v.34 no.3
• /
• pp.951-965
• /
• 2019

Let $f:X{\rightarrow}X$ be a continuous map on a compact metric space (X, d) and for an arbitrary $x{\in}X$, $${\mathcal{SC}}_d(x,f):=\{y{\mid}x{\text{ can be strong }}d-{\text{chain to }}y\}$$. We give an example to show that ${\mathcal{SC}}_d(x,f)$ is dependent on the metric d on X but it is a closed and f-invariant set. We prove that if ${\mathcal{SC}}_d(x,f){\supseteq}{\Omega}(f)$ or f has the asymptotic-average shadowing property, then ${\mathcal{SC}}_d(x,f)=X$. Also, we show that if f has the shadowing property, then ${\lim}\;{\sup}_{n{\in}{\mathbb{N}}}\{f^n\}={\mathcal{SC}}_d(f)$ where ${\mathcal{SC}}_d(f)=\{(x,y){\mid}y{\in}{\mathcal{SC}}_d(x,f)\}$. For each $n{\in}{\mathbb{N}}$, we give an example in which ${\mathcal{SCR}}_d(f^n){\neq}{\mathcal{SCR}}_d(f)$. In spite of it, we prove that if $f^{-1}:(X,d){\rightarrow}(X,d)$ is an equicontinuous map, then ${\mathcal{SCR}}_d(f^n)={\mathcal{SCR}}_d(f)$ for all $n{\in}{\mathbb{N}}$.

• IE interfaces
• /
• v.13 no.3
• /
• pp.378-387
• /
• 2000

As the globalization of manufacturing companies continues, the scope of dependence between these companies and distributors, and other suppliers are growing very rapidly since no one company manufactures or distributes the whole product by themselves. And, the need to increase the efficiency of the whole supply chain is increasing. This paper deals with a multi-plant lot-sizing problem(MPLSP) which happens in a decentralized manufacturing system of a supply chain. In this study, we assume that the whole supply chain is driven by a single source of independent demand and many levels of dependent demands among manufacturing systems in the supply chain. We consider setup cost, transportation cost and time, and inventory holding cost as a decision factor in the MPLSP. The MPLSP is decomposed into two sub-problems: a planning problem of the whole supply chain and a lot-sizing problem of each manufacturing system. The supply chain planning problem becomes a pure linear programming problem and a Generalized Goal Decomposition method is used to solve the problem. Its result is used as a goal of the lot-sizing problem. The lot-sizing problem is solved using the CPLEX package, and then the coefficients of the planning problem are updated reflecting the lot-sizing solution. This procedure is repeated until termination criteria are met. The whole solution process is similar to Lagrangian relaxation method in the sense that the solutions are approaching the optimum in a recursive manner. Through experiments, the proposed closed-loop hierarchical planning and traditional hierarchical planning are compared to optimal solution, and it is shown that the proposed method is a very viable alternative for solving production planning problems of decentralized manufacturing systems and in other areas.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.11
• /
• pp.4282-4290
• /
• 2010

Recently, business environment is spreading from singular business to supply-chain problem. SCM(Supply Chain Management) is changing from closed and static to opened and dynamic environment, so these environment changes of SCM require to enterprise different approach than past. As supply chain is becoming opened and dynamic, a claim is being naming that converse of real-time the get reaction from to recognizing the level of supply chain problem, grope of alternative plan to solving this problem and choosing optimum alternative plan raise the enterprise competitive. But until present, the research to deal with these changes of SCM is on insufficient situation. Thus in this paper proposes the agent system by a way of realizing dynamic supply chain. The agent is going to accomplish the management activities in real-time depends on environment and given condition and designed for solving problems development and maintenance. Also, algorithms performance of the agent is tested on TAC SCM environment. Agents in TAC SCM are simulations of small manufacturers, who must compete with each other for both supplies and customers, and manage inventories and production facilities.