• Smart Structures and Systems
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• v.13 no.2
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• pp.305-318
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• 2014

This paper numerically investigates the feasibility of an active mass damper (AMD) system using the time delay control (TDC) algorithm, which is one of the robust and adaptive control algorithms, for effectively suppressing the excessive vibration of a building structure under wind loading. Because of its several attractive features such as the simplicity and the excellent robustness to unknown system dynamics and disturbance, the TDC algorithm has the potential to be an effective control system for mitigating the vibration of civil engineering structures such as buildings and bridges. However, it has not been used for structural response reduction yet. In this study, therefore, the active control method combining an AMD system with the TDC algorithm is first proposed in order to reduce the wind-induced vibration of a building structure and its effectiveness is numerically examined. To this end, its stability analysis is first performed; and then, a series of numerical simulations are conducted. It is demonstrated that the proposed active structural control system can effectively reduce the acceleration response of the building structure.

• Journal of Korean Association for Spatial Structures
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• v.21 no.3
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• pp.77-84
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• 2021

In this study, In order to apply the U-flanged truss hybrid beam to the actual construction site, the structural design of the basic module of the middle and low-rise neighborhood living facilities was performed according to the Korea Design Standard, and the construction cost and construction period were compared with the traditional reinforced concrete structure system. As a result of analyzing the construction cost for the basic module, if the U-flanged truss hybrid beam and D-Deck slab system are used, the construction cost can be reduced by 86% compared to the traditional reinforced concrete structure system. In addition, as a result of analyzing the construction period for a floor area of 1,000m², using the U-flanged truss hybrid beam and D-Deck slab system can save 2.0days in construction period compared to the traditional reinforced concrete structure system. Therefore, the U-flange truss hybrid beam can secure sufficient economic feasibility compared to the existing reinforced concrete method in terms of cost reduction and shortening of construction period.

• Journal of Korea Trade
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• v.25 no.2
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• pp.1-21
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• 2021

Purpose - The purpose of this research is to develop two medical tourism system models which explain medical tourism phenomenon with a systemic approach. Design/methodology - This research was conducted by using a qualitative data analysis which mainly refers to previous references of medical tourism in the areas of tourism and medicine. Leiper's tourism system model was utilized as a conceptual framework. In-depth interviews with experts in the field were conducted in order to pretest the models. Findings - This research suggests a medical tourism system framework and a medical service provision framework. The first model presents medical tourism components and their relationships within a framework presented in a diagram. The second model shows the relationships among medical services required by medical tourists, the service providers, and service human resources along with movements of medical tourists. Originality/value - The first model presents a spatial composition of medical tourism components and their relationships, whereas the second model shows the linkage among medical services, the service providers, and relevant service human resources along with time sequential steps of medical tourists. These two models are complementary and may be used as useful tools to observe medical tourism phenomenon with a systemic and holistic approach. These two models may enable stake holders avoid unnecessary confusions and conflicts that result in duplication of government policies and a waste of budget and human resources.

• Journal of Drive and Control
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• v.16 no.2
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• pp.15-21
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• 2019

In this study, the maximum system efficiency of the electro-hydrostatic actuators was experimentally investigated, where small size external gear pumps with volumetric displacement under 1.3 cc/rev were combined with a 400W servomotor as the prime mover. Since the efficiency data of the servomotor, gear pumps and hydraulic cylinder were not provided by the suppliers, experimental apparatuses for their efficiency measurement were extra built up. When a gear pump with a volumetric displacement of 1.27cc/rev was used on an electro-hydrostatic actuator system, the maximum system efficiency was not higher than 70%. This was because the most effective operation ranges of the motor and pump did not coincide each other. In order to match their operation ranges as one of the most crucial design factors, a speed reduction mechanism can be used, such as a timing belt. It was shown in the study that the maximum system efficiency could be increased from 70% to 76% in that way.

• Journal of the Korean Society of Clothing and Textiles
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• v.44 no.6
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• pp.1139-1153
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• 2020

Upper body types were classified to develop the sizing system of the cycling wear top for the high school male cyclist. The research methods were performed using the anthropometric measurements of 111 high school male cyclists that included cluster analysis was performed. The research results are as follows. Type 1 (23.4%) has the longest biocromion length, is the tallest of the three types and a proper body type. Type 2 (25.2%) has the largest weight and developed muscles in the chest parts. Type 3 (51.4%) is the shortest of the three types and is a skinny body with a bending back. In order to develop a sizing system, the 12 anthropometric measurements were selected for correlation analysis. The bust circumference and stature were presented as the control dimensions of sizing system. The waist front, waist back length and biacromion length were less correlated with other items; consequently, they were independent items and were set as referable dimensions. Therefore, it was proposed as a sizing system because the 5 cm of bust and 5 cm of stature have a high coverage by body type. The total coverage rate was 81.9%.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.2
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• pp.153-158
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• 2021

In order to mitigate the vulnerability of the satellite navigation system against radio frequency interference, South Korea has been developing advanced terrestrial navigation system (eLoran) technology since 2016. The eLoran system synchronizes the transmission time of the pulse used in the existing Loran-C system with UTC and transmits correction information that can improve the position error. The eLoran system is known to reduce the position error of about 460 m of the existing Loran-C system to 20 m, and for this, the transmitter must be able to transmit eLoran signals according to more stringent standards. For this reason, an international standard that further developed the Loran-C signal standard established by US Coast Guard was established by Society of Automotive Engineers (SAE) International. In this paper, based on the analysis of the SAE9990 document, the international standard for eLoran transmission signals, a standard inspection process was produced to check whether the eLoran transmitter is transmitting signals in accordance with the standard.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.93-101
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• 2021

The purpose of this study is to analyze the adequacy of production capacity of the assembly process system of mobile bath vehicle's top box panel and process design through a simulation analysis. Towards this end, the layout of the facility designed with pre-verification job using a simulation modeling and an experiment, and facility, logistics process, and personnel input method were made into a simulation model, and the design system's adequacy was evaluated through an experiment. To produce 120 mobile bath vehicles annually, it was analyzed that 14 general workers and seven skilled workers were adequate through the experiment. It was also identified that three painting process lines carried out through outsourcing were adequate. Production lead time was 201.7 hours on average and it was 230 hours maximum. To meet customer delivery service level of 95% within the deadline when establishing a customer order and vehicle delivery plan, it was analyzed that more than 215 hours of lead time is needed minimum. If the process cycle time is reduced to 85% upon system stabilization and skillfulness improvement, it was analyzed that annual output of 147 vehicles can be achieved without additional production line expansion.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.11
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• pp.3875-3891
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• 2021

In this study, a Velostat pressure sensor was manufactured to develop a plantar pressure measurement system and a C#-based application was developed to monitor and collect plantar pressure data in real time. In order to evaluate the characteristics of the proposed plantar pressure measurement system, the accuracy of plantar pressure index and personal classification was verified by comparing with MatScan, a commercial plantar pressure measurement system. As a result, the output characteristics according to the weight of the Velostat pressure sensor were evaluated and a trend line with the reliability of r² = 0.98 was detected. The Root Mean Square Error(RMSE) of the weighted area was 11.315 cm², the RMSE of the x coordinate of Center of Pressure(CoP_x) was 1.036 cm and the RMSE of the y coordinate of Center of Pressure(CoP_y) was 0.936 cm. Finally, inaccuracy of personal classification, the proposed system was 99.47% and MatScan was 96.86%. Based on the advantage of being simple to implement and capable of manufacturing at low cost, it is considered that it can be applied to various fields of measuring vital signs such as sitting posture and breathing in addition to the plantar pressure measurement system.

• Journal of the Korean Chemical Society
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• v.7 no.4
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• pp.283-287
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• 1963

The distribution ratio of hydrogen cupferrate in $H_2O-CHCl_3$ system was considered as a function of pH ($HClO_4$), ionic strength ($NaClO_4$), and cupferron concentration in perchloric acid media, respectively. The values were independent upon pH (1.50∼3.00 range) and ionic strength (0.1∼2.00 range), but they increased as increasing the cupferron concentration in the acidic media. At the infinite dilution, the thermodynamic distribution ratio between chloroform and aqueous phase was 120. 0. The activity coefficients of hydrogen cupferrate in chloroform solution were determined by the distribution ratio. This activity coefficient may be calculated by using the empirical equation, $-log\;f_{CHCl3}=0.1285C_{CHCl3}+{7.775C^2}_{CHCl3}$ which represents the experimental data quite well for the solution in 0.1 mole/l order of hydrogen cupferrate concentration.

• The Journal of Korean Physical Therapy
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• v.34 no.2
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• pp.80-89
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• 2022

Purpose: In Japan, the long-term care insurance and health insurance acts have stipulated the visiting rehabilitation system to provide support at the national level. The prior case of Japan would provide guidelines for seeking a suitable policy direction in South Korea. This study aims to examine the historical transition process of the visiting rehabilitation system in Japan, and the issues that emerged in the process of the institutionalization of this system. Methods: To examine the historical transition process of the system, the regulations announced by the government and their reports were reviewed. The relevant issues were qualitatively analyzed based on the opinions of scholars, therapists, and interested organizations that were reported in published papers on the topic. Result: The visiting rehabilitation system has been implemented in the following chronological order: The Health and Medical Service Act for the aged (1982-2006), the Health Insurance Act (1988-), and the Long-term Care Insurance Act (2000-). Currently, visiting rehabilitation is provided through hospitals, clinics, visiting nursing stations, etc. The following issues came to the fore in the process of the institutionalization of the system: (1) the complexity of the system, (2) the necessity of changing perceptions into a life model approach, (3) insufficient service provision by therapists, (4) the lack of human resources and an education system, (5) the lack of awareness of care managers and doctors about visiting rehabilitation, and (6) the necessity of quality enhancement through a team approach. Conclusion: It is deemed worthwhile to refer to the visiting rehabilitation system in Japan and the issues that emerged in the process of institutionalizing the system while seeking a policy direction for a similar system in South Korea.