• Journal of applied mathematics & informatics
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• v.40 no.5_6
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• pp.933-947
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• 2022

In this research, we presented the type 2 fuzzy transportation problem with additional constraints and solved by our proposed genetic algorithm model, and the results are verified using the softwares, genetic algorithm tool in Matlab and Lingo. The goal of our approach is to minimize the cost in solving a transportation problem with an additional constraint (TPAC) using the genetic algorithm (GA) based type 2 fuzzy parameter. We reduced the type 2 fuzzy set (T₂FS) into a type 1 fuzzy set (T₁FS) using a critical value-based reduction method (CVRM). Also, we use the centroid method (CM) to obtain the corresponding crisp value for this reduced fuzzy set. To achieve the best solution, GA is applied to TPAC in type 2 fuzzy parameters. A real-life situation is considered to illustrate the method.

• Journal of the Korean Mathematical Society
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• v.61 no.5
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• pp.953-973
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• 2024

Let R = ⊕_α∈Γ R_α be a commutative ring graded by an arbitrary torsionless monoid Γ. A homogeneous prime ideal P of R is said to be strongly homogeneous prime if aP and bR are comparable for any homogeneous elements a, b of R. We will say that R is a graded pseudo-valuation ring (gr-PVR for short) if every homogeneous prime ideal of R is strongly homogeneous prime. In this paper, we introduce and study the graded version of the pseudo-valuation rings which is a generalization of the gr-pseudo-valuation domains in the context of arbitrary Γ-graded rings (with zero-divisors). We then study the possible transfer of this property to the graded trivial ring extension and the graded amalgamation. Our goal is to provide examples of new classes of Γ-graded rings that satisfy the above mentioned property.

• Journal of Environmental Policy
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• v.9 no.3
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• pp.143-160
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• 2010

This paper estimate the $CO_2$ reduction potential that can be achieved by improving the technical efficiency of input factors in the manufacturing sector. Technical efficiency in each manufacturing firm was estimated using the DEA technique. Depending on the returns-to-scale assumption selected, average technical efficiency was estimated to be between 0.467 and 0.643. These estimates suggest that, when the efficiency of electricity consumption in the manufacturing sector is improved, the overall $CO_2$ emissions can be reduced by 17.1-25.5%. Recently, the Korean government has adopted a low-carbon-green-growth policy with the goal of reducing greenhouse gas emissions by 30% below the BAU level by year 2020. The analysis of the paper suggests that this goal can be achieved through improved efficiency of electricity consumption.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.2
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• pp.143-150
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• 1993

Shallow sub-bottom reflection recorders are obtained using dual frequency (15/100 KHz). The main goal of this study is to enhance the resolving power and penetration for the sub-bottom reflection of the sub-marine seismic exploration. The Fresnel zones of spherical waves for the near-field are of great importance to reach the high resoluton. In case a target to detects than the Fresnel radius, a diffraction hyperbola on the recorder is observed. A larger attenuation of sand makes less penetration than the smaller attenuation of silt and clay. It is found that the selective frequency as well as the seismic energy generation is the most important factors for sub-marine exploration. This technique of using dual frequency sub-marine exploration may be applied to detect the sub-bottom sludge soil, ocean contamination and marine archaeological relics.

• Korean Journal of Materials Research
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• v.34 no.4
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• pp.202-207
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• 2024

In this study, we undertook detailed experiments to increase hydrogen production efficiency by optimizing the thickness of titanium dioxide (TiO₂) thin films. TiO₂ films were deposited on p-type silicon (Si) wafers using atomic layer deposition (ALD) technology. The main goal was to identify the optimal thickness of TiO₂ film that would maximize hydrogen production efficiency while maintaining stable operating conditions. The photoelectrochemical (PEC) properties of the TiO₂ films of different thicknesses were evaluated using open circuit potential (OCP) and linear sweep voltammetry (LSV) analysis. These techniques play a pivotal role in evaluating the electrochemical behavior and photoactivity of semiconductor materials in PEC systems. Our results showed photovoltage tended to improve with increasing thickness of TiO₂ deposition. However, this improvement was observed to plateau and eventually decline when the thickness exceeded 1.5 nm, showing a correlation between charge transfer efficiency and tunneling. On the other hand, LSV analysis showed bare Si had the greatest efficiency, and that the deposition of TiO₂ caused a positive change in the formation of photovoltage, but was not optimal. We show that oxide tunneling-capable TiO₂ film thicknesses of 1~2 nm have the potential to improve the efficiency of PEC hydrogen production systems. This study not only reveals the complex relationship between film thickness and PEC performance, but also enabled greater efficiency and set a benchmark for future research aimed at developing sustainable hydrogen production technologies.

• Journal of the Korean Home Economics Association
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• v.50 no.8
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• pp.97-112
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• 2012

The purpose of this study is to develop the concept of manner leadership for adolescents based on the manner of the East and leadership of the West. Also, it is to investigate the influence of manner leadership on happiness of adolescents. For this, manner leadership was developed through literature review, focus group interview, empirical study, in-depth interview, exploratory factor analysis, and confirmatory factor analysis. The sub-dimensions of manner leadership consisted of time management, academic performance, goal attainment and citizenship behavior, communication, family relationship, social relationship, image management and conflict resolution. The data were obtained by administering a self-reported questionnaire to high school students residing in Seoul. Statistical analyses were carried out using SPSS and AMOS. The main results of the study can be summarized as follows. First, the level of the adolescents' manner leadership tended to be more than average. In addition, they were good at image management but time management was absolutely lacking among the sub-dimension of manner leadership. On the other hand, it appeared that the adolescents' happiness level was lower than the manner leadership. Second, the result of the study was that the manner leadership was positively correlated with happiness of adolescents. Finally, happiness of adolescents was affected on these variables, such as grade, self-efficacy, emotional intimacy between mother and adolescent, time management, goal attainment, communication, and family relationship. Based on this study, it is expected that the manner leadership programs for enhancing happiness for adolescents would be developed.

• Earthquakes and Structures
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• v.23 no.2
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• pp.115-128
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• 2022

One common method to select input ground motions to predict dynamic behavior of structures subjected to seismic excitation requires spectral acceleration (S_a) match target mean response spectrum. However, dispersion of ground motions, which explicitly affects the structural response, is rarely discussed in this method. Generally, selecting ground motions matching target mean and variance has been utilized as an appropriate method to predict reliable seismic response. The goal of this paper is to investigate the impact of target spectra variance of ground motions on structural seismic response. Two sets of ground motions with different target variances (zero variance and minimum variance larger than inherent variance of the target spectrum) are selected as input to two different structures. Structural responses at different heights are compared, in terms of peak, mean and dispersion. Results show that increase of target spectra variance tends to increase peak floor acceleration, peak deformation and dispersions of response of interest remarkably. To short-period structures, dispersion increase ratios of seismic response are close to that of S_a of input ground motions at the first period. To long-period structures, dispersions of floor acceleration and floor response spectra increase more significantly at the bottom, while dispersion increase ratios of IDR and deformation are close to that of S_a of input ground motions at the first period. This study could further provide useful information on selecting appropriate ground motion to predict seismic behavior of different types of structures.

• Korean Medical Education Review
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• v.16 no.1
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• pp.32-41
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• 2014

The purpose of this study was to investigate the differences in non-cognitive factors, specifically achievement goal orientation (AGO) and self-regulated learning (SRL), influencing the academic achievement (AC) of medical and nursing students. 186 students, including 110 medical students and 76 nursing students, completed a survey, which addressed the factors of AGO and SRL. There were significant differences in the factors that affected the academic achievement of medical and nursing students. Multiple regression revealed that the AC of medical students was significantly more affected by mastery-approach AGO (p<0.05), seeking information (p<0.001), and rehearsing/memorizing SRL (p<0.01), while the AC of nursing students was affected by performance-approach AGO, self-efficacy (p<0.001), and time-management SRL. Analysis of variance revealed that significant differences in the sub-factors of AGO and SRL between the medical and nursing students. Thus, it was found that the academic achievement of medical and nursing students was influenced by non-cognitive factors, but there were significant differences in the sub-factors by group. It is suggested that comparative studies with other student groups and a longitudinal study of medical and nursing students need to be conducted, and a personalized counseling and learning intervention focusing on non-cognitive factors should be provided to medical and nursing students.

• Atmosphere
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• v.32 no.4
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• pp.307-322
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• 2022

A drone has recently got attention as an instrument for weather observation in lower atmosphere because it can produce the high spatiotemporal resolution weather data even though the weather phenomenon is inaccessible. Sea fog is a weather phenomenon occurred in lower atmosphere, and has observational limitations because it occurs on the sea. Therefore, goal of this study is to analyze the vertical structures about inflow, development and dispersion of sea fog using the high-resolution weather data with the meteorological sensor-equipped drone. This study observed sea fogs in the west coast of the Korean peninsula from March to October 2021 and investigated one sea fog inflowed into the coast on June 8th 2021. θ_e - q_v diagrams (θ_e: equivalent potential temperature, q_v: water vapor ratio) and vertical wind structures were analyzed. At inflow of sea fog, moist adiabatically stable layer was formed in 0-300 m and prevailing wind was switched from south-southwesterly to west-southwesterly under 120 m. Both changes are favorable for sea fog on the location. θ_e and q_v plummeted in a layer 0-183 m. The inflowed sea fog developed from 183 m to 327 m by mixing with ambient atmosphere on top of sea fog. Also, strong mechanical turbulence near ground drove a vertical mixing under stable layer. At dispersion of sea fog, as θ_e on ground gradually increased, air condition was changed to neutral. Evaporation occurred on both bottom and top in sea fog. These results induced dissipation of sea fog.

• Korean Journal of Child Studies
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• v.37 no.2
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• pp.169-187
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• 2016

Objective: This study aimed to identify profiles based on early childhood and elementary school teachers' goal orientations and to examine differences in teacher efficacy, psychological wellbeing, and job satisfaction among these profile groups. Methods: Data were collected through a teacher questionnaire. The teacher goal-orientation scale consisted of six sub-dimensions: growth, leisure, wealth, relationship, promotion, and social contribution. Data were analyzed using latent profile analyses. Results: Latent profile analyses revealed three distinct profile groups: one group characterized by higher scores across all six dimensions (balanced-goal-orientation group); another characterized by lower scores on all six dimensions, with a relatively higher score on the relationship dimension (relationship-goal-oriented group); another one characterized by lower scores on all dimensions except the leisure goal (leisure-goal-oriented group). MANOVA showed that the balanced-goalorientation group was significantly higher in total years of teaching, educational attainment, and age, compared to the leisure-goal-oriented group. In regression analyses, when controlling for educational attainment, teacher types (kindergarten vs. elementary school) did not significantly predict each of the dummy-coded profile groups (0 = no, 1 = yes). When taking into account teachers' age and educational attainment, belonging to the balanced-goal-orientation group was consistently associated with higher levels of teacher efficacy, job satisfaction, and psychological well-being, whereas the opposite pattern was observed in leisure-goal-oriented group. Conclusion: These findings imply that it is crucial to help pre- and in-service kindergarten and elementary school teachers foster a balance between different types of goals, which would ultimately strengthen and stabilize the supply of a teaching force and the provision of a better education.