• Korean Journal of Construction Engineering and Management
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• v.13 no.1
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• pp.140-147
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• 2012

Climate changes caused by fossil fuel energy usages have led to serious environmental damages and resource scarcity. Ever-increasing demand for energy causes harsh competition in international energy markets. Nuclear power, which once was regarded as a desirable clean energy, began to face public oppositions after the Japanese nuclear disaster in 2011. In this context, wind power is now considered to be an ever-more important recyclable energy source. Thus, this study intended to identify critical success factors for wind power construction projects. After a thorough literature review, two focus group interview sessions were conducted. A questionnaire-based survey, coupled with the two previous methods, resulted in the extraction of important factors for the success of wind power projects. Experts, including those working as constructors, designers, and owners, were paid a direct visit for the interview and survey. The critical success factors were categorized into feasibility study, right policies, equipment selection, and project financing issues. The proposed critical success factors are expected to be an effective guideline for future investors in wind powers.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.193-199
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• 2016

The aim of this study is to determine factors that affect the competitiveness and the move-in environment of migration companies according to the recent change of location conditions of industrial complexes. The results of analysis show that productive factor and economic factor are related to the main factors that determine the location environment. The resident companies have a strong link to the economic characteristics factors, which seems to be related to the expectation and satisfaction for public support facilities, hospitals, educational institutions, and administrative agencies to be placed in the complex, encouraging companies to be located in the complex. In other words, if the existing economic factors and public support facilities were complemented, it can be inferred that the industrial complex promotion policies will be more effectively planned. Also, transportation and infrastructure facilities are analyzed as successful factors for resident companies. In addition, the economic and productive environments turn out to affect public support facilities and environmental factors of infrastructure as major factors. The results of this study are expected to be a useful guideline in determining the resident policy or external factors for the future industrial complex.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3A
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• pp.149-160
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• 2012

Corrugated steel plates have several advantages such as high resistance for shear without stiffeners, minimization of welding process, and high fatigue resistance. To take advantage of these benefits, several researchers have attempted to use corrugated steel plate as a web of I-girders. The lateral-torsional buckling is the major design aspect of such I-girders. However, lateral-torsional buckling of the I-girder with corrugated steel webs still needs to be investigated especially for a real loading condition such as non-uniform bending. This paper investigated the lateral-torsional buckling strength of the I-girder with corrugated steel webs under linear moment gradient by using finite element analysis. From the results, it was found that the buckling behavior of the I-girder with corrugated steel webs differed depending on the number of periods of the corrugation. Also, a simple equation for the moment gradient correction factor of the I-girder with corrugated steel webs was suggested. The inelastic lateral-torsional buckling strength of the I-girder with corrugated steel webs was then discussed based on current design equations for ordinary I-girders and the results of finite element analysis.

• Earthquakes and Structures
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• v.13 no.1
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• pp.59-66
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• 2017

Modern seismic codes rely on performance-based seismic design methodology which requires that the structures withstand inelastic deformation. Many studies have focused on the inelastic deformation ratio evaluation (ratio between the inelastic and elastic maximum lateral displacement demands) for various inelastic spectra. This paper investigates the inelastic response spectra through the ductility demand ${\mu}$, the yield strength reduction factor $R_y$, and the inelastic deformation ratio. They depend on the vibration period T, the post-to-preyield stiffness ratio ${\alpha}$, the peak ground acceleration (PGA), and the normalized yield strength coefficient ${\eta}$ (ratio of yield strength coefficient divided by the PGA). A new inelastic deformation ratio $C_{\eta}$ is defined; it is related to the capacity curve (pushover curve) through the coefficient (${\eta}$) and the ratio (${\alpha}$) that are used as control parameters. A set of 140 real ground motions is selected. The structures are bilinear inelastic single degree of freedom systems (SDOF). The sensitivity of the resulting inelastic deformation ratio mean values is discussed for different levels of normalized yield strength coefficient. The influence of vibration period T, post-to-preyield stiffness ratio ${\alpha}$, normalized yield strength coefficient ${\eta}$, earthquake magnitude, ruptures distance (i.e., to fault rupture) and site conditions is also investigated. A regression analysis leads to simplified expressions of this inelastic deformation ratio. These simplified equations estimate the inelastic deformation ratio for structures, which is a key parameter for design or evaluation. The results show that, for a given level of normalized yield strength coefficient, these inelastic displacement ratios become non sensitive to none of the rupture distance, the earthquake magnitude or the site class. Furthermore, they show that the post-to-preyield stiffness has a negligible effect on the inelastic deformation ratio if the normalized yield strength coefficient is greater than unity.

• Science of Emotion and Sensibility
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• v.20 no.4
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• pp.31-40
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• 2017

This research aims to investigate 'Hallyu' contents consumption tendency of consumers from Korea, Japan, and the United States by analyzing their emotional responses. With the development of social media, research on emotion analysis by reviewing text materials has grown. Whereas environmental variables affect consumer demand towards 'Hallyu' contents, little comparative analyses have been conducted on the emotional responses of consumers from different countries. In this research, the emotional prototype model proposed by Russell(1980) used to extract and distinguish emotional words to clarify how people in the three countries differently perceive the Korean drama "Goblin". First of all, the SNS reviews were collected during a two-month period (February 12 to April 12). Second, significant factors were identified in the collected data according to Russell's emotion model. Third, random forest was applied to organize the selected variables in the order of variable importance. Fourth, the correlations among the emotional words were compared. Lastly, the accuracy of the trained model was measured using the test dataset. The results show that "Happy" was found to be the greatest factor in Korea and in the United States and "Pleased" in Japan. Emotional words correlations showed that when watching the drama "Goblin", "passive unpleasure" was the main factor associated with individual's interest in Korea whereas "passive pleasure" was associated with individual's interest in Japan and in the United States. Based on the results, this research suggests the possibility of developing evaluation guidelines for emotional responses of different countries towards 'Hallyu' contents.

• Parasites, Hosts and Diseases
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• v.53 no.5
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• pp.553-559
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• 2015

Research on micro-level assessment of the changes of socio-economic status following health interventions is very scarce. The use of household asset data to determine wealth indices is a common procedure for estimating socio-economic position in resource poor settings. In such settings information about income is usually lacking, and the collection of individual consumption or expenditure data would require in-depth interviews, posing a considerable risk of bias. In this study, we determined the socio-economic status of 213 households in a community population in an island in the north-western Tanzania before and 3 year after implementation of a participatory hygiene and sanitation transformation (PHAST) intervention to control schistosomiasis and intestinal worm infections. We constructed a household 'wealth index' based housing construction features (e.g., type of roof, walls, and floor) and durable assets ownership (e.g., bicycle, radio, etc.). We employed principal components analysis and classified households into wealth quintiles. The study revealed that asset variables with positive factor scores were associated with higher socio-economic status, whereas asset variables with negative factor scores were associated with lower socio-economic status. Overall, households which were rated as the poorest and very poor were on the decrease, whereas those rated as poor, less poor, and the least poor were on the increase after PHAST intervention. This decrease/increase was significant. The median shifted from -0.4376677 to 0.5001073, and the mean from -0.2605787 (SD; 2.005688) to 0.2605787 (SD; 1.831199). The difference in socio-economic status of the people between the 2 phases was highly statistically significant (P<0.001). We argue that finding of this study should be treated with caution as there were other interventions to control schistosomiasis and intestinal worm infections which were running concurrently on Kome Island apart from PHAST intervention.

• Journal of Korea Water Resources Association
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• v.51 no.spc
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• pp.1161-1169
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• 2018

In this study, a new methodology was proposed to evaluate the flood vulnerability of river levee and to investigate the effect on the levee where the water level changes according to climate change. The stability of levee against seepage was evaluated using SEEP/W model which is two-dimensional groundwater infiltration model. In addition to the infiltration behavior, it is necessary to analyze the vulnerability of the embankment considering the environmental conditions of the river due to climate change. In this study, the levee flood vulnerability index (LFVI) was newly developed by deriving the factors necessary for the analysis of the levee vulnerability. The size of river levee was investigated by selecting the target area. The selected levees were classified into upstream part, midstream part and downstream part at the nearside of Seoul in the Han river, and the safety factor of the levee was analyzed by applying the design flood level of the levee. The safety ratio of the levee was analyzed by applying the design flood level considering the current flood level and the scenario of climate change RCP8.5. The degree of change resulting from climate change was identified for each factor that forms the levee flood vulnerability index. By using the levee flood vulnerability index value utilizing these factors comprehensively, it was finally possible to estimate the vulnerability of levee due to climate change.

• Journal of The Korean Association For Science Education
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• v.38 no.6
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• pp.825-838
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• 2018

The purpose of this study is to develop a survey tool of scientific character for elementary student which connects science education and character education effectively by figuring out traits of elementary students' character being presented in teaching and learning context of elementary school science. For this, we adapted the theocratical model from the previous research which defined scientific character as the competencies being able to practice in concrete teaching and learning context of science. Based on this model, we developed the survey tool as 'Scientific Character Inventory for Elementary Student' to assess elementary students' scientific character as the competences to practice the virtues being pursued in the context of elementary school science and verified its reliability and validity. As a result of an exploratory and confirmatory factor analysis, we confirmed all the items could be summarized into 28 items and eight constructs such as scientific problem-solving, self-management, self-reflection, communication, interpersonal skill, community participation, global citizenship, and environmental ethics awareness. We found that minimum reliability coefficient of constructs was over than 0.5 and reliability coefficient of the total items was 0.878. And also, there was modest relationship between each construct and the total score of scientific character. These results show that the developed survey tool can be useful in evaluating the effectiveness of science character education. This study is meaningful in that it systematically reveals constructs of scientific character which can be raised in concrete context of science teaching and learning so as to suggest the survey tool to assess this.

• Composites Research
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• v.32 no.1
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• pp.78-84
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• 2019

This study focused on the prediction of the long-term performance of carbon fiber/epoxy composites using Dynamic Mechanical Analysis (DMA) and Time-Temperature Superposition (TTS). Single-frequency test, multi-frequency test, and creep TTS test were performed. A sinusoidal load of $20{\mu}m$ amplitude was applied while increasing the temperature from $-30^{\circ}C$ to $240^{\circ}C$ at $2^{\circ}C/min$ for the single-frequency test and the multi-frequency test. The frequencies applied to the multi-frequency test were 0.316, 1, 3.16, 10 and 31.6 Hz. In the creep TTS test, a stress of 15 MPa was applied for 10 minutes at every $10^{\circ}C$ from $-30^{\circ}C$ to $230^{\circ}C$. The glass transition temperature was determined by single-frequency test. The activation energy and the storage modulus curve for each temperature were obtained from glass transition temperature for each frequency by the multi-frequency test. The master curve for the reference temperature was obtained by applying the shift factor using the Arrhenius equation. Also, TTS test was used to obtain the creep compliance curves for each temperature and the master curve for the reference temperature by applying the shift factors using the manual shift technique. The master curve obtained through this process can be applied to predict the long-term performance of carbon fiber/epoxy composites for a given environmental condition.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.92-101
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• 2020

It is necessary to develop a rational method for evaluating the safety of bridges for the passage of inseparable crane vehicles exceeding the limit weight. In this study, the same method applied to the development of the recently introduced reliability-based highway bridge design code - limit state design method is applied to the calibration of the live load factor for the crane vehicle. Structural analysis was performed on the concrete bridge and the required strengths of the previous design code, the current design code and AASHTO LRFD were compared. When comparing the unfactored live load effect, the live load of the crane was greater than that of the current and previous design code. When comparing the required strength by applying the calibrated live load factor, the previous design code demands the largest strength and the current design code and the crane live load effect yields similar value. The results of safety evaluation of the actual bridges on the candidate route for the crane passage secured the same reliability as the target reliability index required by the design code and the strength of the cross section of the actual bridge is calculated greater than the required strength for the passage of the crane, which confirms the safety for the passage of the crane.