• Journal of Bio-Environment Control
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• v.28 no.1
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• pp.16-27
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• 2019

Using virtual reality technology, users can learn and experience many interactions in virtual space like the actual physical space. This study was conducted to develop air flow simulator that allows farmers and consultants to consult air flow through VR devices by creating a greenhouse or pigpen model. It can help educate farmers about the importance of ventilation effects for agricultural facilities. We proposed CFD visualization system by building a virtual reality environment and constructing database of CFD and structure of agricultural facilities. After consultants can set up situations according to environmental conditions, the users experience the visualized air flow of agricultural facility according to the ventilation effects. Also it can provide a quantified environmental distribution in the agricultural facility. Currently, the CFD data in agricultural facilities are established during winter and summer. In order to experience various environmental conditions in the developed system, The experts need to run CFD data under various environmental conditions and register them in the system requirements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.3
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• pp.461-467
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• 2019

Advances in location-aware and IoT (Internet of Things) technology increase the rapid generation of massive movement data. Knowledge discovery from massive movement data helps us to understand the urban flow and traffic management. This paper proposes a method to analyze frequent origin-destination sequence patterns from irregular spatiotemporal taxi pick-up locations. The proposed method starts by conducting cluster analysis and then run a frequent sequence pattern analysis based on identified clusters as a base unit. The experimental data is Seoul taxi trajectory data between 7 a.m. and 9 a.m. during one week. The experimental results present that significant frequent sequence patterns occur within Gangnam. The significant frequent sequence patterns of different regions are identified between Gangnam and Seoul City Hall area. Further, this study uses administrative boundaries as a base unit. The results based on administrative boundaries fails to detect the frequent sequence patterns between different regions. The proposed method can be applied to decrease not only taxis' empty-loaded rate, but also improve urban flow management.

• Geophysics and Geophysical Exploration
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• v.24 no.2
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• pp.35-44
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• 2021

As the execution speed of Python is slower than those of other programming languages (e.g., C, C++, and FORTRAN), Python is not considered to be efficient for writing numerical geodynamic code that requires numerous iterations. Recently, many computational techniques, such as the Just-In-Time (JIT) compiler, have been developed to enhance the calculation speed of Python. Here, we developed two-dimensional (2D) numerical geodynamic code that was optimized for the JIT compiler, based on Python. Our code simulates mantle convection by combining the Particle-In-Cell (PIC) scheme and the finite element method (FEM), which are both commonly used in geodynamic modeling. We benchmarked well-known mantle convection problems to evaluate the reliability of our code, which confirmed that the root mean square velocity and Nusselt number obtained from our numerical modeling were consistent with those of the mantle convection problems. The matrix assembly and PIC processes in our code, when run with the JIT compiler, successfully achieved a speed-up 30× and 258× faster than without the JIT compiler, respectively. Our Python-based FEM-PIC code shows the high potential of Python for geodynamic modeling cases that require complex computations.

• 한국사회정책
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• v.24 no.4
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• pp.185-222
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• 2017

The purpose of this study is to investigate the effect of labor market policy on fiscal soundness of welfare state. The analysis was carried out using cross-sectional panel data regression analysis, stepwise mediating effect analysis and system GMM designed by Baron and Kenny(1986) based on the data from 1985 to 2015 for 20 OECD countries. In setting up the analysis model, this study considers the interaction effect between active and passive labor market policies as well as the time sequence of the outcomes which have been overlooked in the previous studies. The result shows that labor market policies have significant impacts on the fiscal condition of welfare states, which is measured as the levels of national debt in this study. Especially the expenditure on active labor market programs has a positive effect on improving the fiscal soundness of welfare states by promoting the employment rate. In contrast, passive labor market programs expenditure is negatively associated with employment rate growth and it exacerbates the burden of national debt in the short-term. However, when active labor market programs and passive labor market programs are combined, the negative impacts by passive pabor market policies on the fiscal soundness of welfare states are off-set. Therefore this study addresses that although the expansion of the labor market policies can be inimical to the fiscal soundness of welfare states in the short-term, in the long run, they can have effective roles in securing and promoting the fiscal soundness of the welfare states by promoting the employment rate.

• (The)Study of the Eastern Classic
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• no.37
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• pp.345-375
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• 2009

In relation to body conception, the introduction of western medicine to Joseon Korea started off some points in disputes: the one was whether the western anatomy was positive or not, the other was whether the cognition was ruled by heart or brain. In the long run of these disputes, that who had clarified the change of body conception was Choi Han Kee. His new conception of body was characterized as follow: on the one hand, it emphasized the mechanical conception of body; on the other hand, it emphasized the cognitive ability of body. But that his conception of body had obscure points: that is, its mechanical conception was intervened by chi(神氣), and his doctrine of cognition searched for the origin of cognition in balance of chi of the body. He had set up this conception of body by the combination of western medicine and chi, but the combination did not seem to be perfect. This point had appeared again in his conception of physics that he thought the basis of medicine. He had pursed the combination of chemical element and chi, but it could not be accomplished successfully unless he had abandoned the organicist conception of chi. In conclusion, his new conception of body was not free from the suspicion of a incomplete tentative construction.

• The Southeast Asian review
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• v.28 no.4
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• pp.161-196
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• 2018

The major object of this study is to analyze the political development of Myanmar's civilian government on the concept of defective democracy, and to investigate the main actors who delayed or stymied political development and their interrelation. In doing so, this study suggests the tasks required for political development overcoming the current political structure and behavior. The civilian government, which was launched in 2016, failed to achieve positive political development by following the behavior of military authoritarianism in terms of exercise of power and decision making structure. On the perspective of the government, delegative democracy and domain democracy have been strengthening since one person has taken over all political power and hesitate to take horizontal accountability for each power organizations. The military, which is responsible for national defence and security seeks illiberal democracy and exclusive democracy, keeping on an undemocratic constitution by the military and Burman ethnocentrism. The reasons why defective democracy has been occurred are that the lack of a group to run a democratic institutions and the limitation of power structure that fails to adhere to the principle of civilian control to the military due to long-term military rule. Therefore, there is a need for military's come back to barracks and transform the power structure to democratic of the civilian government which is tamed an authoritarian order for the political development in Myanmar. In order to achieve this, this study concludes that setting up a empowered democratic government is required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.409-414
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• 2021

Tightness performance that blocks compartments is important for surface ships to achieve superior mission performance and survivability in combat environments. To meet the above requirements, airtightness of the structural elements and the appropriate strength to specific areas are checked during a test run after ship construction. In particular, air tests of compartments adjacent to the water surface are performed. In an air test, air is injected into the compartment up to the test pressure of the test memo. The pressure drop value is checked after 10 minutes to determine if the requirements of the corresponding area are satisfied. In summer, however, when the influence of the outside temperature is large, a phenomenon in which the internal pressure increases during the air test was identified. This phenomenon reduces the reliability of the test result. Therefore, a system was designed to compensate for temperature changes in the compartments through this study. The developed system calculates the amount of pressure change caused by a temperature change in the compartment and outputs a correction value. The pressure change was calculated using the ideal gas equation, reflecting the maintenance, increase, and decrease in temperature during the test process. A comparison of the calculated pressure correction value with the database of NIST REFPROP revealed a difference of 0.126% to a maximum of 0.253%.

• Journal of IKEEE
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• v.26 no.3
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• pp.483-487
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• 2022

In this paper, we design a self-powered Arduino system for solar energy harvesting and explain its operation. To perform the operation, the Arduino system senses the amount of solar energy that changes every moment and adjusts the ratio of the active mode and sleep mode operation time according to a given solar light intensity. If the intensity of sunlight is strong enough, the Arduino system can be continuously driven in active mode and receive sufficient power from sunlight. If not, the system can run in sleep mode to minimize power consumption. As a result, it can be seen that energy consumption can be minimized by reducing power consumption by up to 81.7% when using sleep mode compared to continuously driving active mode. Also, when the light intensity is at an intermediate level, the ratio between the active mode and the sleep mode is appropriately adjusted according to the light intensity to operate. The method of self-control of the operating time ratio of active mode and sleep mode, proposed in this paper, is thought to be helpful in energy-efficient operation of the self-powered systems for wearables and bio-health applications.

• Journal of International Area Studies (JIAS)
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• v.14 no.2
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• pp.477-498
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• 2010

The Reasons which Rose Revolution, Orange Revolution, and Lemon Revolution had been much argued in international society are as follows: Firstly, the important fact was that authoritarian governments in Georgia, Ukraine and Kyrgyzstan were collapsed not by physical violences and military forces, but by unblooded civil movements, so called Civil Revolution. And it is also called as Colorful Revolution. Secondly, during the advance of three Civil Revolution, hegemony conflicts between Russia and western powers including US appeared. In fact, tensions between the two countries, Russia and US had already occurred in Post-soviet region after dissolution of Soviet Union. Thirdly, as a result of three Civil Revolution, there were built up fullest attentions in international societies about the possibilities of other civil revolutions, that is to say, 'Colorful Revolution' among the countries which were the republics of former USSR. In this respect, in this investigation of Lemon Revolution in Kyrgyzstan as like Rose Revolution in Georgia and Orange Revolution in Ukraine, this article examined the roles and supports toward NGOs of Western powers including US. To my opinion, it is likely that NGOs, with powerful sponsors, become political bodies working through networks and media rather than being rooted in civil society and acting on behalf of citizens. And that powerful sponsors, directly or indirectly financed by outside governments, become involved in political activities. So NGOs have been important roles in promoting civil revolution as political agencies and more political instruments of foreign governments. In the long run, through the Colorful Revolution, it is better to understand that hegemony struggle is beginning between external concerned superpowers including US and Russia, rather than hegemony struggle having directly broke out.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.95-104
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• 2022

Micro hydropower is a readily available renewable energy source that can be harvested utilizing hydrokinetic turbines from shallow water canals, irrigation and industrial channel flows, and run-off river stream flows. These sources generally have low head (<1 m) and low velocity which makes it difficult to harvest energy using conventional turbines. A horizontal-axis screw turbine was designed and numerically tested to extract power from such low-head water sources. The 3-bladed screw-type turbine is placed horizontally perpendicular to the incoming flow, partially submerged in a narrow water channel at no-head condition. The turbine hydraulic performances were studied using Computational Fluid Dynamics models. Turbine design parameters such as the shroud diameter, the hub-to-shroud ratios, and the submerged depths were obtained through a steady-state parametric study. The resulting turbine configuration was then tested by solving the unsteady multiphase free-surface equations mimicking an actual open channel flow scenario. The turbine performance in the shallow channel were studied for various Tip Speed Ratios (TSR). The highest power coefficient was obtained at a TSR of 0.3. The turbine was then scaled-up to test its performance on a real site condition at a head of 0.3 m. The highest power coefficient obtained was 0.18. Several losses were observed in the 3-bladed turbine design and to minimize losses, the number of blades were increased to five. The power coefficient improved by 236% for a 5-bladed screw turbine. The fluid losses were minimized by increasing the blade surface area submerged in water. The turbine performance was increased by 74.4% after dipping the turbine to a bottom wall clearance of 30 cm from 60 cm. The final output of the novel horizontal-axis screw turbine showed a 2.83 kW power output at a power coefficient of 0.63. The turbine is expected to produce 18,744 kWh/year of electricity. The design feasibility test of the turbine showed promising results to harvest energy from small hydropower sources.