• Journal of Power Electronics
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• v.10 no.1
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• pp.9-13
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• 2010

This paper proposes an input-series-output-parallel connected ZVS full bridge converter with interleaved control for photovoltaic power conditioning systems (PV PCS). The input-series connection enables a fully modular power-system architecture, where low voltage and standard power modules can be connected in any combination at the input and/or at the output, to realize any given specifications. Further, the input-series connection enables the use of low-voltage MOSFETs that are optimized for a very low RDSON, thus, resulting in lower conduction losses. The system costs decrease due to the reduced current, and the volumes of the output filters due to the interleaving technique. A topology for a photovoltaic (PV) dc/dc converter that can dramatically reduce the power rating and increase the efficiency of a PV system by analyzing the PV module characteristics is proposed. The control scheme, consisting of an output voltage loop, a current loop and input voltage balancing loops, is proposed to achieve input voltage sharing and output current sharing. The total PV system is implemented for a 10-kW PV power conditioning system (PCS). This system has a dc/dc converter with a 3.6-kW power rating. It is only one-third of the total PV PCS power. A 3.6-kW prototype PV dc/dc converter is introduced to experimentally verify the proposed topology. In addition, experimental results show that the proposed topology exhibits good performance.

• Journal of KIISE:Information Networking
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• v.41 no.4
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• pp.177-185
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• 2014

It has been occurred many times that wireless sensor networks (WSNs) had congested areas because all the sensing data collected by multiple sensor nodes are delivered to one sink node. Typically, in order to control congested areas, it used to reduce the traffic by increasing the sensing period or discarding packets. However, those schemes have a disadvantage that it loses the reliability when delivering sensing data. Moreover, there are no schemes considering case of having poor quality of links between nodes in practical terms. In this paper, we suggest a scheme not to reduce the traffic but to distribute the traffic by changing routing paths depends on the traffic and the quality of links. Also, it can be seen that the reliability of delivering of the sensing data is improved with the experiments improving collection rates and shortening end-to-end delay.

• PNF and Movement
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• v.16 no.1
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• pp.93-103
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• 2018

Purpose: The aim of this study was to investigate the effect of goal-oriented side walking training on balance and gait in chronic stroke patients. Methods: This study involved 18 chronic stroke patients who were divided into an experimental group (n=9) and a control group (n=9). The experimental group performed goal-oriented side walking training, and the control group performed general side walking training. The walking variables assessed were walking speed, stride length, and 10-m walking time. The balance variables assessed were foot pressure, timed up and go test (TUG), and Berg balance scale (BBS). These variables were measured before and after the exercise. Wilcoxon's signed-rank test was used to compare the participants' performances before and after the intervention in both groups. The Mann-Whitney U test was conducted for between-group comparisons after the intervention. Statistical significance was set at ${\alpha}=0.05$ Results: Walking speed, stride length, 10-m walking time, TUG, and foot pressure were significantly improved in both groups after the exercise (p<0.05). The between-group comparison showed a significant improvement in the goal-oriented side walking group (p<0.05). However, there were no significant between-group differences in 10-m walking times (p>0.05) and BBS (p=0.05). Conclusion: The results revealed that goal-oriented side walking training was effective in improving the balancing and walking ability of chronic stroke patients.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.10 no.1
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• pp.23-28
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• 2012

Purpose : The objectives of this study were to examine changes in gait parameters related to the COP and gait velocity resulting from the use of ankle foot orthosis, and to provide information for the prescription of ankle foot orthosis and gait rehabilitation training. Methods : We sampled a control group of 14 normal children of the same age as the spastic diplegia (spastic diplegia used ankle foot orthosis) and measured their COP at barefoot gait and their gait parameters at three gait velocities. Change in the COP according to the use of ankle foot orthosis measured one-way ANOVA and Gait parameters according to gait velocity used repeated measures ANOVA. Results : As a result of analyzing change in the COP it became close to that of normal children, and changes in gait parameters such as step width, stride length and stride time also became close to those of normal children. Conclusion : In conclusion, when spastic diplegia used ankle foot orthosis, their balancing ability was improved as a result of decreased change in the COP, and their changes in gait parameters also became close to those of the control group. These results show that the use of ankle foot orthosis improves spastic diplegia gait functions.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.6
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• pp.435-447
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• 2004

For VOD systems, it is important to provide QoS to more users under the limited resources. To analyze QoS issues in real environment, we implement clustered VOD server and embedded client system based on the Linux open source platform. The parallel processing of MPEG data, load balancing for nodes and VCR like functions are implemented in the server side. To provide more user friendly interface, the general TV is used for a VOD client's terminal and the embedded board is used supporting for VCR functions. In this paper, we measure the performance of the implemented VOD system under the various user requirement features and evaluate the sources of performance limitations. From these analyses, we propose the dynamic admission control method based on the availability memory and network bandwidth. The proposed method enhances the utilization of the system resource for the more QoS media streams.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.2
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• pp.82-89
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• 2021

This study proposes a DAB two-stage series structure with insulated bidirectional DC-DC converter for two-way power transfer between the renewable energy of high voltages (1 kV and above). The proposed circuit transforms the existing DAB converter into a two-stage series structure to reduce the pressure in the switch. The problem of power imbalance occurring in the design of the DAB converter second-stage series is improved by applying the cell balancing method circuit and the common mode coupled inductor using an external flying capacitor instead of reflecting the existing improvement measures, voltage balance control, and inductor current control. In addition, a no-load supercharging sequence is proposed in high voltages and high-speed switching by using the fixed duty output method. This study presents the analysis results through the structure of the proposed circuit, the principle of improving the power imbalance problem, and simulations. Prototypes were manufactured to meet the specifications of input/output voltage of 1700 V, maximum load of 65 kW, and switching frequency of 51kHz, and the validity of the topology was verified using the experimental results and efficiency data.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.1
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• pp.34-41
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• 2022

In vivo oocytes grow and mature in ovarian follicles whereas oocytes are matured in vitro in plastic culture dishes with a hard surface. In vivo oocytes show a superior developmental ability to in vitro counterparts, indicating suboptimal environments of in vitro culture. This study aimed to evaluate the influence of an agarose matrix as a culture substrate during in vitro maturation (IVM) on the development of pig oocytes derived from small antral follicles (SAFs). Cumulus-oocyte complexes (COCs) retrieved from SAFs were grown in a plastic culture dish without an agarose matrix and then cultured for maturation in a plastic dish coated without (control) or with a 1% or 2% (w/v) agarose hydrogel. Then, the effect of the soft agarose matrix on oocyte maturation and embryonic development was assessed by analyzing intra-oocyte contents of glutathione (GSH) and reactive oxygen species (ROS), expression of VEGFA, HIF1A, and PFKP genes, and blastocyst formation after parthenogenesis. IVM of pig COCs on a 1% (w/v) agarose matrix showed a significantly higher blastocyst formation, intra-oocyte GSH contents, and transcript abundance of VEGFA. Moreover, a significantly lower intra-oocyte ROS content was detected in oocytes matured on the 1% and 2% (w/v) agarose matrices than in control. Our results demonstrated that IVM of SAFs-derived pig oocytes on a soft agarose matrix enhanced developmental ability by improving the cytoplasmic maturation of oocytes through redox balancing and regulation of gene expression.

• Journal of the Korean Society of Physical Medicine
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• v.17 no.2
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• pp.1-10
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• 2022

PURPOSE: This study examined the effects of the low dye taping technique on the static and dynamic balancing ability and navicular bone drop when the low dye taping technique was divided into elastic and non-elastic taping. METHODS: The subjects of the study were 31 volunteers without musculoskeletal disorders. The length (L) and anterior (A), posteromedial, and posterolateral values of the arch in the NO (normal eyes open), NC (normal eyes closed), PO (pillow with eyes open), and PC (pillow with close eyes closed) states were evaluated when barefoot and when Kinesio tape and non-elastic tape were applied. The measurements were analyzed using repeated ANOVA and an independent t-test. Post hoc tests were performed using a Fisher's LSD. RESULTS: A significant difference was found in the arch L and A values using a foot scanner (p < .05). In addition, there was a significant difference in dynamic balance in the three directions (p < .05), and no difference was found in the case of static balance. As a result, non-elastic tape application helps improve the dynamic balance ability and arch of the foot. CONCLUSION: The non-elastic tape technique is helpful for the foot arch function, and there is no difference in the static balance ability between Kinesio tape and non-elastic tape. Nevertheless, non-elastic tape is more helpful for the dynamic balance ability than Kinesio taping.

• Journal of Korean Academy of Nursing
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• v.29 no.2
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• pp.429-444
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• 1999

This study was performed to explore the effects of a dance therapy on physical and psychological characteristics in the elderly. The design of this study was a non-equivalent pre-post test experiment. The subjects consisted of elderly persons living in a facility located in Suweon and Bucheon. Fifty eight subjects, aged between 65 and 93 years who had normal cognition, sensory function, balance, and resting blood pressure. They underwent tests of balance, flexibility, muscle strength, depression, and anxiety as baseline data before dance therapy, and at 6th week and at the end of the 12nd week after following dance therapy. Twenty seven elderly persons were assigned to the experimental group and participated with the dance therapy between April and July, 1998. The dance therapy was developed by the author with the help of a dance therapist and a physiatrist. This therapy was based on the Marian Chace's dance therapy and Korean traditional dance with music. The dance therapy consists of 50 minutes session, 3 times a week for 12 weeks. One session was consisted of warming-up, expression, catharsis, sharing, and closing stage. The intensity of the dance therapy was at the 40 % of age-adjusted maximum heart rates. Data were analysed with mead standard deviation, Chi-square test, unpaired t-test, repeated measures ANOVA, and Bonferroni multiple regression using SAS program. 1. The results related to the physical characteristics were as follows : 1) The balance (standing on one leg, walking on the balancing bar), flexibility and muscle strength (knee extensor, knee flexor, ankle plantarflexor and dorsiflexor) of the experimental subjects significantly increased over time mere than that of the control subjects. 2) The experimental group had significantly higher score for balance, flexibility, muscle strength of knee extensor, and knee flexor than the control group at the 12nd week after dance therapy. 3) The experimental group had significantly higher score for muscle strength of ankle dorsiflexor and plantarflexor than the control group at the 6th week and the 12nd week after dance therapy. 2. The results related to psychological characteristics were as follows : 1) Scores of Geriatric Depression Scale, Hamilton Depression Rating Scale, and Zung's Self-rating Anxiety Scale of the experimental group were significantly decreased over time more than that of the control group. 2) The experimental group had significantly lower score for depression than the control group at the 12nd week after dance therapy. 3) The experimental group had significantly lower score for anxiety than the control group at the 6th week and the 12nd week after dance therapy. The findings showed that the dance therapy could be effective in improving the balances, flexibility, and muscle strength of lower limb, and effective in decreasing the depression and anxiety of the elderly. Additional merits of the dance therapy would be inexpensiveness, easy accessibility, and increasing interpersonal relationship. It can be suggested that the dance therapy is effective in the health promotion of the elderly.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.319-327
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• 2019

The muscle activity and balance ability of the acute stroke patient has been checked by the functional electrical stimulation using biofeedback fusion postural control training in this study. Functional electrical stimulation using biofeedback fusion postural control training have been implemented on 15 trainees and general biofeedback fusion postural control training have been implemented on another 15 trainees for 30 minutes at 5 times per week during 8 weeks, and vastus lateralis, vastus medialis, rectus femoris and biceps femoris have been measured using the biceps femoris to evaluate the muscle activity of the lower extremity. The moving surface area, whole path length and limited of stability have been measured using biorecue to measure the balance ability. There was statistically meaningful difference on the vastus lateralis, vastus medialis, rectus femoris and biceps femoris in the muscle activity of the lower extremity and there was statistically meaningful difference on surface area, whole path length and limited of stability in the balancing ability. Based on above, it is realized that the functional electrical stimulation using biofeedback fusion postural control training is more effective than the general biofeedback fusion postural control training on the improvement of the muscle activity of the lower extremity and the balance ability.