• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.187-193
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• 2018

There has been a gradual increase in the demand for the electric power in Korea. In order to meet the demand, power station should have technical functions with increased effectiveness. When accident happens in electric machinery at power stations, huge amount of economic losses and mulfunction of equipments occur. One of the accidents is a deteriorated cables operating power stations. In order to prevent cable accident in advance, we should monitor the insulation status of the cable. Cable accidents are resulting from the junctions. We have developed and installed a device in order to identify the status of junction part of power cable at Korea Western Power Co., Ltd.. We performed an accurate diagnosis for the stable utilization of junctions where the accidents occurs most frequently, and to increase the reliability. In this paper, we present the concepts of our device and the method of monitoring diagnosis for the stable use of junctions at cables predicting the life time of cables by analyzing the data obtained by the device. We also present the hardware aspect of the device we have developed.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.1
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• pp.9-17
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• 2019

Purpose : This study assessed the effects of transcranial direct current stimulation (tDCS) on balance, fall efficacy, and fall-related fitness in stroke patients, using a cohort of 30 stroke patients divided into two groups. Methods : The experimental group (was given transcranial direct current stimulation in a virtual reality program) and the control group was given false tDCS in virtual reality. there were 15 patients in each group, receiving appropriate treatment over 30 sessions (30 minutes per session per week over a six-week period). In order to assess the change in balance before and after the intervention, the Berg Balance scale was utilized. Fall efficacy was evaluated using the Korean Falls Efficacy Scale for the Elderly (FES-K), The following exercises were performed by patients to assess fall-related fitness : sitting down in a chair and standing up : walking a 244 cm round= trip, and standing on one foot. Results : After the intervention, the experimental group exhibited significantly increased fall efficacy and fall-related fitness, while the control group exhibited no change. These findings suggest that tDCS has positive effects on balance, fall efficacy, and fall-related fitness in stroke patients. Conclusion : Using tDCS as an intervention would bring positive effects on balance, fall efficacy, and fall-related fitness in stroke patients undergoing rehabilitation.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.654-664
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• 2018

In this paper, this system is operated by PCS that is driven by being synchronized voltage fed inverter and AC source, and in the steady state of power source charge battery connected to DC side with solar cell using a photovoltaic (PV) that it was so called constant voltage charge. it can cause the effect of energy saving of electric power, from 10 to 20%. and through a normal operation of electric energy storage system (EESS). In addition, better output waveform was generated because of pulse width modulation (PWM) method, and it was Proved to test by experiment maintained constant output voltage regardless of AC source disconnection, load variation, and voltage variation of AC power source.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.3
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• pp.159-169
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• 2019

Purpose: The purpose of this study was to provide an effective method of exercise therapy for patients with cervicogenic headache. Methods: The subjects were divided into the following three groups according to the intervention received: cervix-stabilizing exercise (n=12, group 1), transcranial direct current stimulation (n=12, group 2), and cervix-stabilizing exercise combined with transcranial direct current stimulation (n=12, group 3). The intragroup and intergroup differences in muscle characteristics and neck disability index were compared and analyzed. Results: The comparison and analysis of the changes in muscle tone and post hoc analysis revealed statistically significant intragroup decreases in the upper trapezius and suboccipitals in groups I and III, and statistically significant intergroup differences in the upper trapezius, with greater changes in group III than in group II, and in the suboccipitals, with greater changes in groupIII than in groups Iand II. The comparison and analysis of the change in muscle stiffness and post hoc analysis revealed a statistically significanti ntra group decrease in the upper trapezius in group Iand suboccipitals in group III, and a statistically significant intergroup difference in both muscles, with greater change in group III than in group II. The comparison and analysis of change in neck disability index and post hoc analysis revealed a statistically significant intragroup decrease in all the three groups and a statistically significant intergroup difference, with greater change in group III than in groups I and II. Conclusion: The neck-stabilizing exercise and transcranial direct current stimulation were shown to be effective in decreasing the tone of the cervical muscles by stabilizing the cervical bone and improving muscle durability, and in improving the movement and limitation of joint range of motion by decreasing muscle tone and stiffness.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.4
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• pp.300-308
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• 2019

For drones to be used for industrial or agricultural applications, it is necessary to increase the payload and endurance. Currently, the payload and endurance are limited by the battery technology for electric powered drones. In addition, charging or replacing the batteries may not be a practical solution at the field that requires near continuous operation. In this paper, a procedure to optimize the power system of an electric hybrid drone that consists of an internal combustion engine, a generator, a battery, and electric motors is presented. The example drone for crop dusting is sized for easy transportation with a maximum takeoff weight of 200 kg. The two main rotors that are mechanically connected to the internal combustion engine provides most of the lift. The drone is controled by four electric motors that are driven by the generator. By analyzing the flow of the energy, a methodology to select the optimum propeller and motor among the commercially available models is described. Then, a procedure of finding the optimum operational condition along with the proper gear reduction ratios for the internal combustion engine based on the test data is presented.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.4
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• pp.201-210
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• 2021

Purpose : There is a lack of research on this field in the Republic of Korea, especially those that have seen the effect of interaction between transcranial direct current stimulation and computerized cognitive rehabilitation therapy. This study divided 30 dementia patients into a treatment group, which received transcranial direct current stimulation and computerized cognitive rehabilitation, and a control group, which received pseudo-transcranial direct current stimulation and pseudo-computerized cognitive rehabilitation. This study evaluated the effects of these treatments on the visual perception, cognition functions, and daily activities of dementia patients. Methods : Fifteen subjects were allocated to the treatment group and the other 15 subjects were allocated to the control group. Treatments were given at intervals of five sessions per week (30 minutes per session) for six weeks (30 times in total). This study used the Neurobehavioral Cognitive Status Examination (NCSE) to examine cognitive functions, MVPT to evaluate visual perception, and FIM to test daily living activities before and after applying the treatments. Results : The results of this study showed that cognitive functions, visual perception, and daily living activities significantly (p<.05) improved after the intervention in the treatment group and the control group. The changes in cognitive functions, visual perception, and daily living activities due to the treatments were significantly different between the groups (p<.05). Conclusion : The results indicated that transcranial direct current stimulation and computerized cognitive rehabilitation therapy improved visual perception and daily living activities by increasing cognitive functions. Consequently, it was found that the simultaneous application of transcranial direct current stimulation in conjunction with a computerized cognitive rehabilitation program was an intervention method that could positively affect the visual perception, cognitive function, and daily living activities of dementia patients. Based on the results of this study, the study of arbitration protocols for demential will have to be more active.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.45-52
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• 2021

The space vector control based voltage control method for a three-phase PWM rectifier requires a lot of effort to design an optimal switching pattern since a switching pattern for the switching section must be designed. In this study, a D-Q control based SPWM output voltage control algorithm was studied for the three-phase six-pulse CVS type rectifier. In the output voltage control algorithm, three-phase reference signals are obtained from the D-Q transformation based on the space vector representation method, instead of the switching pattern, SPWM method is used to generate rectifier switching control signals. Next, a three-phase six-pulse CVS PWM rectifier based on D-Q transformation and SPWM was modeled using EMTP-RV. Finally, the validity of the D-Q control-based SPWM voltage control algorithm was confirmed by comparing the output voltage waveform obtained through EMTP-RV simulation works with a reference value and confirming that the output voltage accurately follows the reference voltage.

• PNF and Movement
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• v.11 no.2
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• pp.9-19
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• 2013

Purpose : Study on the effects of attention(working memory) for normal adults by applying transcranial Direct Current Stimulation(tDCS). Methods : There are two groups of 10 random people aged between 20 to 30, one is an experimental group(stimulation) and the other is a comparison group(simulate stimulation). For the 1st da y, pre-stimulation test is executed, and for the 2nd day to the 4th day, tDCS is applied stimulated both on the right prefrontal lobe and the left occipital lobe through the electrode. The stimulation lasts for 15 minutes with voltage power of 1mA for each day. The post-stimulation test is executed on the day of 5th. In this paper, a FAIR attention test is used for measuring the attention. Results : As the result of the experiment, there are significant gaps both on the value of P, the ability of selective attention, and the value of C, the consistent ability after the stimulation on right prefrontal and left occipital lobe. And there is no significant gap on the value Q, the quality(Control). However, all the P, Q, and C values are increased according to the average value between the pre-stimulation test and the post-stimulation. Conclusion : Finally, ability of selective attention and self-control, and consistent attention is progressed by applying the tDCS to the normal people.

• Journal of the Korea Society of Computer and Information
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• v.26 no.2
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• pp.53-60
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• 2021

In this paper, we aimed to identify the insulation characteristics and reliability of Epoxy composites, which are widely used as insulation material for electrical & electronic components and electric appliance. To this end, it was necessary to predict variations of electric field due to the distribution of fillers that must be added by economic and mechanical factors. So, we verified the result using an electric field analysis Simulator. Furthermore, under the condtion of DC voltage application, an dielectirc breakdown test was performed according to ambient temperature changes and the distribution of fillers, and the changes were observed. Three types of specimens were manufactured by adding 0, 50 and 100[phr] filling to Epoxy resin. In all specimens, as temperature was increased, the strength of the dielectric strength was decreased. When comparing the simulation results with the actual dielectric breakdown test results, we was able to confirm the technical applicability required for Insulation design of electric appliance.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.4
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• pp.213-221
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• 2020

Purpose : This study aimed to evaluate the changes in visual perception and daily life activities after simultaneously applying the visual perception training program and transcranial DC stimulation. Particularly, this study tried to understand what changes in abilities among daily life activities influenced cognition. Methods : This study selected 50 dementia patients to achieve the objective. This study applied transcranial DC stimulation and a visual perception training program to a treatment group (n=25) and a visual perception training program to a control group (n=25). The intervention was applied five times per week and 30 minutes per session (total of 30 intervention sessions). This study measured visual perception functions and daily life activities using MVPT and FIM before and after applying the intervention. Results : The visual perception, mobility of daily life activities, cognition, and total score of the treatment group (n=25), which received the visual perception training program and transcranial DC at the same time, were significantly (p<.05) different between before and after the intervention. Moreover, when the visual perception and daily life activities of the treatment group and those of the control group after implementing the intervention were compared, they were significantly (p<.05) different between the two groups. Conclusion : The results of this study showed that the simultaneous application of the visual perception training program and transcranial DC stimulation was an effective means to enhance the visual perception and daily life activities of dementia patients. The results implied that transcranial DC stimulation, as well as the application of visual perception training program, as well as a visual perception training program, was effective for improving the visual perception functions and daily life activities dementia patients and simultaneous application of the two interventions would increase the effect even further.