• Journal of The Korean Association For Science Education
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• v.26 no.3
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• pp.356-366
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• 2006

The purpose of this study was to investigate the effects of offering similar experiences for hypothesis-generation based on abduction. Two hundred and seventy eight students in Seoul(8th and 10th grades) were requested to propose causal questions and generate hypotheses after observing an unfamiliar situation. Then, after having been presented numerous similar experimental situations to initial situation, the students were asked to regenerate a hypothesis. When the $X^2$ analysis was done to determine differences in hypothesis generation before and after offering the similar experimental situations, a meaningful difference appeared(p<.001). This study proposes that offering similar experimental situations ease hypothesis-generation based on abductive reasoning. Additionally, the second meaningful difference was discovered when the $X^2$ analysis was carried out to find differences in causal question proposal and hypothesis generation among students who had varied cognitive levels(p<.05) Considering the findings of the study, a progressive stage offering similar scenarios may further abductive reasoning while implementing lessons related to hypothesis generation in middle and high school.

• Korea Journal of Hospital Management
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• v.20 no.1
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• pp.1-12
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• 2015

This study aims to examine the effect of a change of leadership on internal environment and organization effectiveness and suggest measures on effective organizational management by analyzing a change of leadership before and after 2nd generation management. There was analysis of a difference of leadership type, organizational structure, organizational culture, management resources, job satisfaction, and organizational commitment between the period of the founders and the period of 2nd generation successors by collecting data from employees of 6 hospitals in Seoul. Also there was analysis of the effect of a change of leadership on internal environment and organizational effectiveness. According to the analysis, it was demonstrated that the factor affecting job satisfaction during the period of the founder was complexity of organizational structure, and there were no factors affecting organizational commitment. In contrast, during the period of the 2nd generation successors, it was revealed that transformational leadership, centralism of organizational structure, and human resources of management resources affect job satisfaction, and transformational leadership, complexity of organizational structure, hierarchical culture of organizational culture, and human resources of management resources affect organizational commitment. Further, after the succession from the founders to 2nd generation successors, as transformational leadership increased, job satisfaction rose, and as developmental culture was reinforced and human resources increased, organizational commitment was heightened. Furthermore, as transformational leadership increased and developmental culture was reinforced, organizational commitment was heightened. Namely, as transformational leadership was reinforced resulting from the succession to 2nd generation, employees' job satisfaction and organizational commitment increased, with circumstances aiming for the actual change.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.2
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• pp.149-154
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• 2023

In the Fourth Industrial Revolution, hydrogen energy is in the spotlight. There is a difficulty in commercialization due to the lack of hydrogen infrastructure. Therefore, a lot of hydrogen should be imported and a method using ammonia is the most useful. In this study, using the mixed gas of hydrogen and nitrogen generated when ammonia is decomposed, the hydrogen separation performance is to be tested. Hydrogen was separated using an electrochemical hydrogen compressor based on a fuel cell and the experiment was conducted by changing the ratio of hydrogen and nitrogen. In addition, the performance was also compared by the difference both the pressure and the membrane.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.8-16
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• 2007

Finite element analysis (FEA) is an effective means for the analysis of bioelectromagnetism. It has been successfully applied to various problems over conventional methods such as boundary element analysis and finite difference analysis. However, its utilization has been limited due to the overwhelming computational load despite of its analytical power. We have previously developed a novel mesh generation scheme that produces FE meshes that are content-adaptive to given MR images. MRI content-adaptive FE meshes (cMeshes) represent the electrically conducting domain more effectively with far less number of nodes and elements, thus lessen the computational load. In general, the cMesh generation is affected by the quality of feature maps derived from MRI. In this study, we have tested various feature maps created based on the improved differential geometry measures for more effective cMesh head models. As performance indices, correlation coefficient (CC), root mean squared error (RMSE), relative error (RE), and the quality of cMesh triangle elements are used. The results show that there is a significant variation according to the characteristics of specific feature maps on cMesh generation, and offer additional choices of feature maps to yield more effective and efficient generation of cMeshes. We believe that cMeshes with specific and improved feature map generation schemes should be useful in the FEA of bioelectromagnetic problems.

• The korean journal of orthodontics
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• v.46 no.6
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• pp.364-371
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• 2016

Objective: With the introduction of third-generation light-emitting diodes (LEDs) in dental practice, it is necessary to compare their bracket-bonding effects, safety, and efficacy with those of the second-generation units. Methods: In this study, 80 extracted human premolars were randomly divided into eight groups of 10 samples each. Metal or polycrystalline ceramic brackets were bonded on the teeth using second- or third-generation LED light-curing units (LCUs), according to the manufacturers' instructions. The shear bond strengths were measured using the universal testing machine, and the adhesive remnant index (ARI) was scored by assessing the residual resin on the surfaces of debonded teeth using a scanning electron microscope. In addition, curing times were also measured. Results: The shear bond strengths in all experimental groups were higher than the acceptable clinical shear bond strengths, regardless of the curing unit used. In both LED LCU groups, all ceramic bracket groups showed significantly higher shear bond strengths than did the metal bracket groups except the plasma emulation group which showed no significant difference. When comparing units within the same bracket type, no differences in shear bond strength were observed between the second- and third-generation unit groups. Additionally, no significant differences were observed among the groups for the ARI. Conclusions: The bracket-bonding effects and ARIs of second- and third-generation LED LCUs showed few differences, and most were without statistical significance; however, the curing time was shorter for the second-generation unit.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.205-211
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• 2010

Effects of operating parameters on electrical properties and ozone generation of Plasma Gun for ballast water treatment were investigated in a laboratory scale experiment. Electrical discharges and ozone generation initiated with applying voltages higher than discharge onset value. Ozone concentration was almost linearly increased with the increase of applied voltage. The optimum electrode gap distance which gave the optimum energy efficiency of ozone generation was 1.95 mm in the experimented apparatus. The effect of inner electrode material on the electrical energy transfer was negligible, however, the difference of electrical and thermal conductivities between electrode materials significantly influenced the ozone generation. In a constant geometrical structure, the electrical energy density played an important role in the ozone generation. The increase of oxygen content in the feeding gas enhanced the ozone generation by lowering ionization potential and promoting ozone source.

• Journal of the Korea Society of Computer and Information
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• v.26 no.10
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• pp.27-35
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• 2021

Local search has been used to solve various combinatorial optimization problems. One of the most important factors in local search is the method of generating a neighbor solution. In this paper, we propose neighbor generation strategies of local search for permutation-based combinatorial optimization, and compare the performance of each strategies targeting the traveling salesman problem. In this paper, we propose a total of 10 neighbor generation strategies. Basically, we propose 4 new strategies such as Rotation in addition to the 4 strategies such as Swap which have been widely used in the past. In addition, there are Combined1 and Combined2, which are made by combining basic neighbor generation strategies. The experiment was performed by applying the basic local search, but changing only the neighbor generation strategy. As a result of the experiment, it was confirmed that the performance difference is large according to the neighbor generation strategy, and also confirmed that the performance of Combined2 is the best. In addition, it was confirmed that Combined2 shows better performance than the existing local search methods.

• Journal of Korea Entertainment Industry Association
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• v.13 no.7
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• pp.39-60
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• 2019

The purpose of this study is to examine new types of political participation using the new media of digital convergence generation. For this purpose, groups were classified according to age and characteristics of media usage to investigate whether there are differences in media-related tendencies, SNS and characteristics of Smartphone usage political-related characteristics, and political participation by types. The results of the study is that the media usage characteristics by generation showed a difference between groups according to the high and low motivation for using media, and there was a generation differences in politics-related characteristics and types of political participation. Digital generation showed lower political involvement, political efficiency and offline political participation than Web 1.0 generation. In addition, political efficacy showed the moderating effect that had the greatest effect on political participation by types.

• Korean Management Science Review
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• v.17 no.1
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• pp.117-134
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• 2000

Pubilc utility industries including the electric utility industry are facing a new stream of privatization com-petition with the private sector and deregulation. The necewssity to solve now and in the future power supply and demand problems has been increasing through the sophisticated generation expansion plan(GEP) approach con-sidering not only KEPCo's supply-side resources but also outside resources such as non-utility generation(NUG) demand-side management (DSM). Under the environmental situation in the current electric utility industry a new approach is needed to acquire multiple resources competitively. This study presents the development of a modified electric generation expansion analysis system(EGEAS) model with avoided cost based on the existing EGEAS model which is a dynamic program to develope an optimal generation expansion plan for the electric utility. We are trying to find optimal GEP in Korea's case using our modified model and observe the difference for the level of reliabilities such as the reserve margin(RM) loss of load probability(LOLP) and expected unserved energy percent(EUEP) between the existing EGEAS model and our model. In addition we are trying to calculate avoided cost for NUG resources which is a criterion to evaluate herem and test possibility of connection calculation of avoided cost with GEP implementation using our modified model. The results of our case study are as follows. First we were able to find that the generation expansion plan and reliability measures were largely influenced by capacity size and loading status of NUG resources, Second we were able to find that avoided cost which are criteria to evaluate NUG resources could be calculated by using our modified EGEAS model with avoided cost. We also note that avoided costs were calculated by our model in connection with generation expansion plans.

• Journal of Digital Convergence
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• v.18 no.5
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• pp.513-520
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• 2020

This research aims to examine the difference in participation motivation, participation experience and identity negotiation between generations of overseas Koreans in the National Sports Festival(NSF). The subjects for this study were 360 overseas Koreans who took part in the 100th NSF held in Seoul in 2019. The results are as follows; First, while the first generation participated in the NSF because of visiting family and maintaining Korean identity, the second generation took part in the event for self-realization. Second, the second generation had more negative experiences than the second generation during the NSF. Third, while the first generation negotiated more identity with origin, the second generation had more identity with settlement.