• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.330-338
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• 2018

The proportional-integral-derivative(PID) controller has been widely used in the industry because of its robust performance and simple structure in a wide range of operating conditions. However, the AVR(Automatic Voltage Regulator) as a control system is not robust to variations of the power system parameters. Therefore, it is necessary to use PID controller to increase the stability and performance of the AVR system. In this paper, a novel design method for determining the optimal PID controller parameters of an AVR system using the particle swarm optimization(PSO) algorithm is presented. The proposed approach has superior features, including easy implementation, stable convergence characteristic and good computational efficiency. In order to assist estimating the performance of the proposed PSO-PID controller, a new performance criterion function is also defined. This evaluation function is intended to reflect when the maximum percentage overshoot, the settling time are given as design specifications. The ITAE evaluation function should impose a penalty if the design specifications are violated, so that the PSO algorithm satisfies the specifications when searching for the PID controller parameter. Finally, through the computer simulations, the proposed PSO-PID controller not only satisfies the given design specifications for the terminal voltage step response, but also shows better control performance than other similar recent studies.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.51-60
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• 2016

The modern state has always followed a variety of risks in the industrialization and informatization trends in the development of science and technology. Under such an environment, A matter of State compensation should take into consideration a variety of values such as harmony relief victims' rights in accordance with the principles of the rule of law, suppression of illegal acts of public servants, ensuring stable performance of official duties, the national treasury stability. As the state takes responsibility for an act of a public servant in a modern constitutional state, there may be a doubt on that the state takes responsibility only when there is a deliberation or a mistake. According to the theory of the self-responsibility, which suits the Constitution, the principle of liability with mistake on the State Compensation Law shall be excluded. I agree to the opinion that a subjective responsibility prerequisite such as a deliberation or a mistake is not required in relation to the liability of reparation on the State Compensation Law. Therefore, it is needed to convert the principle of state liability of reparation from the principle of liability with mistake to the principle of liability without mistake through a fundamental revision of the State Compensation Law.

• Therapeutic Science for Rehabilitation
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• v.7 no.1
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• pp.37-50
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• 2018

Objective : The purpose of this study was to develop a competency indicators of occupational therapists for occupation-based intervention by conducting a Delphi survey to occupation-based intervention experts. Methods : After analyzing the data related to occupational therapists indicators in korea, the results of Delphi survey were collected three times from October to December 2016. Based on the results, we developed occupational therapists competency indicators for occupation-based intervention through expert panel's opinions. Results : Based on the eight competency elements, the competency indicators were examined by 133 primary and 133 secondary competency indicators. Finally, 131 competency indicators were developed based on 8 components as occupational therapist competence indicators for occupation-based intervention. The results of the third delphi showed a high level of content validity of .95, stability of .10, convergence of 0, and consensus of 1. Conclusion : The developed occupational therapist competence indicators for occupation-based intervention could be used in various clinical decision making such as occupation-based intervention, education training, education development and evaluation.

• Journal of Advanced Technology Convergence
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• v.2 no.1
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• pp.23-31
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• 2023

This study was described about the EEG response results of tea tree oil fragrance for the development of functional shampoo additives. In the case of experimenters (1) the intensity change of the right brain alpha wave in electroencephalographic (EEG) response was increased after inhalation of the tea tree oil fragrance. (2) the change of physical tension and stress both the left brain and the right brain in EEG response showed a tendency to decrease after inhalation compared to before inhalation of the tea tree fragrance. (3) the mental distraction and stress was decreased after experimenters inhales the tea tree oil fragrances. These means the tea tree fragrances have both mental stability and stress relief. From above results, we prepared the functional shampoo additives with tea tree oil, and the we determined the alpha wave in EEG response after the functional shampoo additive fragrance for experimenters. As results, (4) the alpha wave intensity in left and right brain was significantly decreased after inhaling the functional shampoo additives fragrance. (5) physical tension and stress changes were decreased after inhalation of functional shampoo additive fragrance. (6) mental distraction and stress changes were also decreased after inhalation of functional shampoo additive fragrance. , From above results, the functional shampoo additives could be used as physical and mental relievers. Furthermore, the functional shampoo additives have the effects of scalp calming when the experimenter was treated shampoo with the functional shampoo additives.

• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.401-409
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• 2015

Defects generated in a railroad track that guides the railroad vehicle have the characteristic of growing fast; as such, the detection technology for railroad track defects is very important because defects can eventually cause mass disasters like derailments. In this study, a speed-up test facility was fabricated to investigate the feasibility of using magnetic flux leakage (MFL) technology for defect detection in a railroad track under speed-up condition; a test was conducted using a railroad track specimen with defects. For this purpose, an MFL sensor head dedicated to the configuration of the railroad was designed and test specimens with artificial defects on their surfaces were manufactured. Using the test facility, a speed-up test ranging from 4km/h to 12km/h was performed and defects including locations were successfully detected from MFL signals induced by defects with enhanced visibility by differentiating raw MFL signals. In the future, it should be possible to apply this system to a high-speed railroad inspection car by improving the lift-off stability that is necessary for speed-up of the developed MFL sensor system.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.119-124
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• 2023

This study analyzed the impact of the real estate changes on the unemployment rate in Korea. Using monthly data from January 2013 to February 2023, the study employed a multiple regression analysis model. The key findings are as follows: First, there was a significant causal relationship between the real estate changes and the unemployment rate. Specifically, an increase in the real estate market led to a significant decrease in the unemployment rate, while a decrease in the real estate market resulted in a significant increase in the unemployment rate. Second, an increase in the loan interest rate was found to significantly reduce the unemployment rate, while a rise in interest rates had positive effects on the employment. Furthermore, an increase in inflation was associated with a significant rise in the unemployment rate. Moreover, an increase in the number of permits issued for housing construction significantly reduced the unemployment rate. Lastly, conducting robustness tests by substituting variables did not significantly alter the analysis results, indicating the robustness of the impact of the real estate changes on the unemployment rate. Based on the above analysis, it can be inferred that the fluctuations in real estate prices in South Korea are linked to fluctuations in the unemployment rate, and stable management of the real estate market may contribute to the stability of the unemployment rate.

• Journal of the Korean GEO-environmental Society
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• v.22 no.6
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• pp.17-26
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• 2021

Ground investigation and result analysis generally used to examine all sorts of structures' subsidence or stability can be classified into sandy soil and cohesive soil, and analysis on the liquid limit of soil is utilized to evaluate the physical properties of ground and types or technical behavior of soil. The most widely used method to analyze liquid limit is Casagrande with which liquid limit can be calculated relatively easily; however, it is fairly difficult to apply it to soil equipped with intermediate properties. Therefore, concerning the properties of soil having the intermediate properties of sedimentary ground, this researcher mixed the clay from Yangsan, Gwangyang, and Busan with sandy soil to make intermediate soil and then carried out the test of consistency limit and also evaluated applicability by using the suggested formula of consistency revision. The sample of intermediate soil was the mixture of clay and sandy soil, and to produce intermediate soil, the content (F_c) of fine soil was applied as 50%, 75%, or 100%. Regarding the physical properties of intermediate soil, to maintain the properties of clay in the natural state, bentonite was added at a fixed rate for controlling the properties of clay, and then, consistency was analyzed. By adopting the formula of consistency revision suggested in advanced research, this author analyzed consistency based on the experiment and consistency based on the suggested formula of revision. Also, about intermediate soil collected at the site, consistency based on the experiment and consistency based on the suggested formula of revision were analyzed comparatively, and about intermediate soil collected, this researcher analyzed particle size and calculated the content (F_c) of fine soil to analyze intermediate soil in diverse conditions. Moreover, about intermediate soil collected at the site, the suggested formula of consistency revision was applied to calculate the compression index, and the compression index based on the experiment and the compression index based on the suggested formula were analyzed comparatively to evaluate the applicability of the suggested formula.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.133-146
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• 2017

In recent years, the development and market participation of major makers of next-generation eco-green vehicles has been accelerating. Consumer interest has also increased. Consumer characteristics, consumption type, characteristics of next-generation eco-friendly vehicles, and government policies on next eco-green vehicles. The results of this study are as follows. In Korea, there was no significant difference by gender, age, monthly average income, and consumer type. However, there was no significant difference in purchase intention by gender, age, and monthly income, Respectively. In the case of Japan, there was no significant difference by gender, age, monthly income, and consumer type. In Korea, on the other hand, images such as brand, color, and design have positive effects on eco-friendly vehicles. In the case of Japan, image and stability have a positive effect on consumers' purchasing behavior. Therefore, it is important for Japanese consumers to consider not only the image of purchasing an eco-friendly vehicles, but also the safety of the vehicles body, appear. In the case of Korea, the socio-environmental value-seeking type has a significant relationship with the purchasing intention. In the case of socio-environmental value-seeking type, the government's support policy such as carbon dioxide tax, direct support from the national or local governments, gasoline tax, Carbon tax and fuel related tax relief showed positive effects. In the case of Japan, the price-seeking type and the socio-environmental value-seeking type were found to have a significant relationship with the purchasing intention. Both the price-seeking type and the socio-environmental value-seeking type showed that the carbon dioxide tax, Direct support, gasoline tax, gasoline tax, and carbon tax, etc. have positive effects.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.3
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• pp.115-120
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• 2016

$CeO_2$ is used as a co-catalyst with $TiO_2$ to improve the catalytic activity of $MnO_x$ and characterization of nano-sized powder is identified with de-NOx efficiency. A comparison between $MnO_x-CeO_2/TiO_2$ and single $CeO_2$ was conducted in terms of microstructural analysis to observe the behavior of $CeO_2$ in the ternary catalyst. The $MnO_x-CeO_2/TiO_2$ catalyst was synthesized by sol-gel method and the average particle size of the single $CeO_2$ is about $285{\mu}m$ due to the low thermal stability, whereas the particle size $MnO_x-CeO_2/TiO_2$ is about 130 nm. The strong interaction between Ce and Ti was identified through the EDS mapping by transmission electron microscopy (TEM). The improvement about 20 % of $de-NO_x$ efficiency is observed in the low-temperature ($150^{\circ}C{\sim}250^{\circ}C$) and vigorous oxygen exchange by well-dispersed $CeO_2$ is the reason of catalytic activity improvement.

• Therapeutic Science for Rehabilitation
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• v.9 no.1
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• pp.24-44
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• 2020

Objective : To develop an occupation-based bilateral upper extremity training protocol that can be effectively applied in a medical setting Methods : The research process using the delphi technique was carried out in 3 stages. The first stage was an open questionnaire development stage, The first draft is prepared through literature review and open questions were developed through preliminary research based on the draft. The second stage was the delphi survey. Based on the responses of the experts obtained through the open Delphi survey, the adequacy of the training protocol was shown on a Likert 5 point scale. The items were edited and deleted, reconstructed by analyzing the mean and standard deviation, stability, convergence degree, consensus, and content validity ratio through the questionnaire. The third step was the completion of the protocol. After discussions between researchers, the finalized protocol contents were reorganized to complete the occupation-based bilateral upper extremity training protocol for medical setting. Results : The final protocol consisted of 9 items across 3 areas in the occupation-based intervention selection domain and 81 items across 4 areas in the bilateral upper extremity training domain, intervention period, and evaluation. Conclusions : This study suggests an evidence-based method that collects the opinions of occupational therapists in order to use occupation-based activities as interventions in a situation that currently sees occupational therapy primarily performed in hospitals. It is also meaningful that the bilateral upper extremity training can be applied effectively in clinical situations by concretely presenting.