• Journal of Korean Association for Spatial Structures
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• v.22 no.1
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• pp.17-24
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• 2022

Currently, the construction trend of high-rise structures is changing from a cube-shaped box to a free-form. In the case of free-form structures, it is difficult to predict the behavior of the structure because it induces torsional deformation due to inclined columns and the eccentricity of the structure by the horizontal load. For this reason, it is essential to review the stability by considering the design variables at the design stage. In this paper, the position of the weak vertical member was analyzed by analyzing the behavior of the structure according to the change in the core position of the twisted high-rise structures. In the case of the shear wall, the shear force was found to be high in the order of proximity to the center of gravity of each floor of the structure. In the case of the column, the component force was generated by the axial force of the outermost beam, so the bending moment was concentrated on the inner column with no inclination.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.162-162
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• 2023

Climate change is a complex phenomenon having its impact on diverse sectors. Temperature and precipitation are two of the most fundamental variables used to characterize climate, and changes in these variables can have significant impacts on ecosystems, agriculture, and human societies. This study evaluated the historical (1981-2010) and future (2011-2100) climatic trends in the Seti-Gandaki basin of Nepal based on 5 km resolution Multi Model Ensemble (MME) of 18 Global Climate Models (GCMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) for SSP1-2.6, SSP2-4.5 and SSP5-85 scenarios. For this study, ERA5 reanalysis dataset is used for historical reference dataset instead of observation dataset due to a lack of good observation data in the study area. Results show that the basin has experienced continuous warming and an increased precipitation pattern in the historical period, and this rising trend is projected to be more prominent in the future. The Seti basin hosts 13 operational hydropower projects of different sizes, with 10 more planned by the government. Consequently, the findings of this study could be leveraged to design adaptation measures for existing hydropower schemes and provide a framework for policymakers to formulate climate change policies in the region. Furthermore, the methodology employed in this research could be replicated in other parts of the country to generate precise climate projections and offer guidance to policymakers in devising sustainable development plans for sectors like irrigation and hydropower.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.86-91
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• 2011

Thermal design was conducted for a solar thermal storage system in a medium-temperature range between $200^{\circ}C$ and $400^{\circ}C$. The system was composed of heat pipes as heat carrier and molten salts as phase-change storage material. Each heat pipe penetrated through the storage system and had two heat-exchanging sections at both ends to interact with high-and low-temperature steams, while it exchanged heat with molten salts in the middle section. During a heat-storage mode, the heat pipes transferred heat from the hot steam at one side to the molten salts and it transferred heat from the molten salt to the cold steam at the other side during the heat-dissipating mode. A tube-bank type heat exchanger theory was applied to this design task to meet the required inlet and outlet temperatures of the steams depending on the operation modes. Several design variables were considered including the lengths of evaporator and condenser of a heat pipe, traverse and longitudinal pitches of the pipe, and the number of rows of the heat pipes for two different molten salt baths. An optimum design results were presented with discussion.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.518-521
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• 2011

A PEMFC single cell with the active area of $25cm^2$ was used to verify the effect of water management in the anode. Water management is one of the most critical operating variables. In this paper the effect of operating condition change, such as anode humidification and temperature, was investigated under constant current density of $200mA/cm^2$ where possible anode flooding operating area. Also experiments to observe the effect of the anode and cathode stoichiometry change and flow field design on the water management were performed. The water management was effected by the stoichimetry change. The temperature and humidification change also affected the fuel cell performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.535-543
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• 2014

In the robust optimization field, the robustness of the objective function emphasizes an insensitive design. In general, the robustness of the objective function can be achieved by reducing the change of the objective function with respect to the variation of the design variables and parameters. However, in conventional methods, when an insensitive design is emphasized, the performance of the objective function can be deteriorated. Besides, if the numbers of the design variables are increased, the numerical cost is quite high in robust optimization for nonlinear programming problems. In this research, the robustness index for the objective function and a process of robust optimization are proposed. Moreover, a method using the supremum of linearized functions is also proposed to reduce the computational cost. Mathematical examples are solved for the verification of the proposed method and the results are compared with those from the conventional methods. The proposed approach improves the performance of the objective function and its efficiency.

• Journal of Korean Physical Therapy Science
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• v.28 no.2
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• pp.65-74
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• 2021

Background: The purpose of this study was investigated of effect of neuromuscular electrical stimulation combined with mirror therapy on static balance, weight support and ankle movement incline with chronic stroke patients. Design: Two-group pretest-posttest design. Methods: Thirty chronic stroke patients participated in this study. The study design is a two-group pretest-posttest design. A total of 30 people participated in the study, and 15 people were each assigned to the experimental group and control group. Experimental group received neuromuscular electrical stimulation combined with mirror therapy 30 minutes, and conventional physical therapy 30 minutes. Control group received conventional physical therapy 30 minutes. Both groups were conducted 5 times a week for 4 weeks. static balance and weight support was measured by force plate and ankle movement incline was measured by goniometer. Results: As a result of comparing the static balance, weight support and ankle movement incline change between experimental group and control group, statistically significant differences were found in all variables (p<.05). In the evaluation before and after the intervention, there was a statistically significant difference in all variables in the experimental group (p<.05), but there was no statistically significant difference in the control group (p>.05). Conclusion: Neuromuscular electrical stimulation combined with mirror therapy intervention improves static balance, increase paretic side weight support and ankle movement incline in chronic stroke patients. It could be an effective intervention for improve static balance, weight support and ankle movement for chronic stroke patients.

• Advances in Computational Design
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• v.7 no.4
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• pp.321-343
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• 2022

Museum buildings display artefacts for public education and enjoyment, ensuring their long-term safety and the comfort of visitors by following strict indoor environment control protocols using mechanical Heating, Ventilation and Air Conditioning (HVAC) systems to keep the (environmental) variables at a fixed comfort level. Maintaining this requires constant supply of energy currently mostly sourced from the combustion of fossil fuels which exacerbates climate change. However, a review on the effects of the indoor environmental variables on museum artefacts as well as museum visitors revealed that there is no specific point at which artefact deterioration occurs, and that there are wide ranges of conditions that guarantee the long-term safety of artefacts and human comfort. Visits to museum buildings in hot-humid tropical climate of Nigeria revealed that strict indoor environmental practices were adopted. Even when appropriate micro-climatic conditions are provided for artefacts, mechanical HVAC systems remain necessary for visitor comfort because almost no consideration is given to natural ventilation. With the current global push towards energy management, this paper reviewed passive environmental control practices, architectural design strategies, and discusses the adaptation of double skin façade with jali screens, and the notion of smart materials, which can satisfy the range of requirements for the long-term safety of artefacts and levels of human comfort in buildings in hot-humid tropical climate, without mechanical HVAC systems. This review would inspire more discussions on passive, energy efficient, smart and climate responsible popular architecture, challenging current thinking on the impact of the more accepted representative architecture.

• Journal of Korean Society for Quality Management
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• v.52 no.2
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• pp.377-394
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• 2024

Purpose: To derive the optimal conditions for the Rubber based colloidal suspension manufacturing process, which made using a stirrer, to apply the mixture design method. Methods: We used two process component and one process variable Mixture design to derive the optimal conditions for the process. The response variables were selected for rotational viscometer measures which can represent Rubber based colloidal suspension quality. The input variables were selected as the values of rubber-organic solvent expressed in proportions as process components and stirring amount as a process variable which are controllable factors in the process. Results: Based on the results of the experiment, rubber and organic solvent and the interaction between stirring amount and rubber and the interaction between stirring amount and rubber and organic solvent were significant. Reproducibility of the regression model was confirmed by the observation that the values obtained from the reproducibility experiment fell within the confidence interval. Additionally, the model predictions were found to be in close agreement with the field measurements. Conclusion: In this study, a regression model was developed to predict the viscosity change of colloidal suspensions based on the proportion of rubber based colloidal suspension. The developed regression model can lead to improved product quality.

• Physical Therapy Korea
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• v.28 no.2
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• pp.154-160
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• 2021

Background: Theoretically, balance is affected by the height of center of mass (COM) during quiet standing. However, no one examined this in humans with variables derived from the center of pressure (COP). Objects: We have conducted balance experiment to measure COP data during quiet standing, in order to examine how the COP measures were affected by the height of COM, vision, floor conditions, and gender. Methods: Twenty individuals stood still with feet together and arms at sides for 30 seconds on a force plate. Trials were acquired with three COM heights: 1% increased or decreased, and not changed, with two vision conditions: eyes closed (EC) and eyes open (EO), and with two floor conditions: unstable (foam pad) and stable (force plate) floor. Outcome variables included the mean distance, root mean square distance, total excursion, mean velocity, and 95% confidence circle area. Results: All outcome variables were associated with the COM height (p < 0.0005), vision (p < 0.0005), and floor condition (p < 0.003). The mean velocity and 95% confidence circle area were 5.7% and 21.8% greater, respectively, in raised COM than in lowered COM (24.6 versus 23.2 mm/s; 1,013.4 versus 832.3 mm²). However, there were no interactions between the COM height and vision condition (p > 0.096), and between the COM height and floor condition (p > 0.183) for all outcome variables. Furthermore, there was no gender difference in all outcome variables (p > 0.186). Conclusion: Balance was affected by the change of COM height induced by a weight belt in human. However, the effect was not affected by vision or floor condition. Our results should inform the design of balance exercise program to improve the outcome of the balance training.

• Journal of Korean Physical Therapy Science
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• v.29 no.3
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• pp.75-84
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• 2022

Background: This study was to investigate the effect of non-invasive transcranial direct current stimulation due to hemiplegic patients due to stroke on temporal and spatial gait ability. Design: Randomized sham controlled trial. Methods: For the study method, 42 patients with hemiplegia due to stroke were randomly assigned to 14 patients each, and the general walking group, tDCS walking group, and tDCS (sham) walking group were subjected to 5 times a week, 30 minutes a day, and 6 weeks. In the temporal gait variables of hemiplegic patients due to stroke, the effect of the gait time, gait cycle, single support, double support, swing phase, stance phase, gait speed, cadence were measured. In spatial variables, one step length and one step length were measured. Results: As a result of the study, the EG group significantly increased in the step time, gait velocity, and cadence of the paralysis side in the comparison of temporal walking variables between groups according to the application of tDCS of walking ability in hemiplegic patients due to stroke patients(p<.05). In the change in spatial walking variables between groups according to the application of tDCS, the step length and stride length of the EG group showed a significant increase. Both the comparison of temporal and spatial symmetry walking variables between groups according to tDCS application was not significant(p>.05) Conclusion: As a result, tDCS has an effective effect on the improvement of the gait ability of stroke patients. In particular, it is an effective method of physical therapy that can improve the cadence and speed of gait, which can be combined with the existing gait training to effectively increase the gait of hemiplegia due to stroke patients.