• Plant Journal
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• v.14 no.4
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• pp.39-47
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• 2018

In this research, when the output of the standard coal-fired thermal power plant operating continuously at the rated output of 500 MW is changed to operate at 300 to 500 MW, the amount of sulfur oxide produced and the amount of sulfur oxide in the absorption tower of desulfurization equipment and proposed an extra liquid to gas ratio improvement inversely proportional to the output. In order to calibrate the combustion efficiency at low power, the ratio of sulfur oxides relative to the amount of combustion gas is increased as the excess air ratio is increased. When the concentration of sulfur oxide at the inlet of the desulfurization absorber was changed from 300 to 500 ppm along with the output fluctuation. The liquid to gas ratio of limestone slurry and combustion gas was changed from 10.99 to 16.27. Therefore, if the concentration of sulfur oxides with output of 300 MW is x, The following correlation equation is recommended for the minimum required flow rate of slurry for the reduction of surplus energy due to the increase of the liquid weight at low load. $y1[m^3/sec]=0.11x+3.74$

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.2
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• pp.93-101
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• 2019

The objective of this study is to develop a model which can predict the seismic performance of the slope relatively accurately and efficiently by using artificial neural network(ANN) technique. The quantification of such the seismic performance of the slope is not easy task due to the randomness and the uncertainty of the earthquake input and slope model. Under these circumstances, probabilistic seismic fragility analyses of slope have been carried out by several researchers, and a closed-form equation for slope seismic performance was proposed through a multiple linear regression analysis. However, a traditional statistical linear regression analysis has shown a limit that cannot accurately represent the nonlinearistic relationship between the slope of various conditions and seismic performance. In order to overcome these problems, in this study, we attempted to apply the ANN to generate prediction models of the seismic performance of the slope. The validity of the derived model was verified by comparing this with the conventional multi-linear and multi-nonlinear regression models. As a result, the models obtained through the ANN basically showed excellent performance in predicting the seismic performance of the slope, compared to the models obtained by the statistical regression analyses of the previous study.

• Journal of Digital Convergence
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• v.17 no.11
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• pp.171-181
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• 2019

In order to confirm whether innovation can be realized through the direction that companies pursue, this study empirically analyzed the relationship between strategic directionality and innovation capacity. Specifically, strategic directionality is divided into customer orientation and technology orientation, and innovation capacity is classified into strategic planning capacity, R&D capacity, and technology commercialization capacity based on previous studies. And the effect of customer and technology orientation on each innovation capacity was analyzed. Data collection was carried out by 368 questionnaires from the workers of manufacturing industry in Gyeongbuk area and the proposed hypotheses were tested by using structural equation. As a result, it was confirmed that technology orientation had significant effects on all three innovation capacities. However, the effect of customer orientation on strategic planning capacity and technical commercialization capacity was accepted, but the relationship with R&D capacity was rejected. These results can provide implications for how to draw innovation from the organizational strategic direction and culture perspectives by explaining the impact of organizational orientation on innovation capacity.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.5
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• pp.273-278
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• 2019

In this study, a new simple method for the estimation of hyperelastic material properties by indentation tests is proposed. Among hyperelastic material models, the Yeoh model with three material properties ($C_{10}$, $C_{20}$, $C_{30}$) is adopted to describe the strain energy density in terms of strain invariants. Finite element simulations of the spherical indentation of hyperelastic materials of the Yeoh model with different material properties are performed to establish a database of indentation force-displacement curves. The indentation force-displacement curves are fitted by cubic polynomials, which are approximated as a product of third-order polynomials of ($C_{10}$, $C_{20}$, $C_{30}$). A regression analysis is conducted to determine the coefficients of the equations for the indentation force-displacement curve approximations. A regression equation is used to estimate the hyperelastic material properties. The present method is verified by comparing the estimated material properties with true values.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.19-26
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• 2021

The lattice structure is attracting attention from industry because of its excellent strength and stiffness, ultra-lightweight, and energy absorption capability. Despite these advantages, widespread commercialization is limited by the difficult manufacturing processes for complex shapes. Additive manufacturing is attracting attention as an optimal technology for manufacturing lattice structures as a technology capable of fabricating complex geometric shapes. In this study, a unit cell was formed using a three-dimensional coordinate method. The relative density relational equation according to the boundary box size and strut radius of the unit cell was derived. Simple cubic (SC), body-centered cubic (BCC), and face-centered cubic (FCC) with a controlled relative density were designed using modeling software. The accuracy of the equations for calculating the relative density proposed in this study secured 98.3%, 98.6%, and 96.2% reliability in SC, BCC, and FCC, respectively. A simulation of the lattice structure revealed an increase in compressive yield load with increasing relative density under the same cell arrangement condition. The compressive yield load decreased in the order of SC, BCC, and FCC under the same arrangement conditions. Finally, structural optimization for the compressive load of a 20 mm × 20 mm × 20 mm structure was possible by configuring the SC unit cells in a 3 × 3 × 3 array.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.2
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• pp.113-120
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• 2021

The wave-propagation phenomenon in an infinite medium has been used to describe the physics in many fields of engineering and natural science. Analytical or numerical methods have been developed to obtain solutions to problems related to the wave-propagation phenomenon. Energy radiation into infinite regions must be accurately considered for accurate solutions to these problems; hence, various numerical and mechanical models as well as boundary conditions have been developed. This paper proposes a new boundary condition that can be applied to scalar-wave or horizontally-polarized shear-wave (or SH-wave) propagation problems in layered waveguides. A governing equation is obtained for the SH waves by applying finite-element discretization in the vertical direction of the waveguide and subsequently modified to derive the boundary condition for the infinite region of the waveguide. Using the orthogonality of the eigenmodes for the SH waves in a layered waveguide, the new boundary condition is shown to be equivalent to the existing root-finding absorbing boundary condition; further, the accuracy is shown to increase with the degree of the new boundary condition, and its stability can be proven. The accuracy and stability are then demonstrated by applying the proposed boundary condition to wave-propagation problems in layered waveguides.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.1
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• pp.21-35
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• 2021

Based on social capital theory, this study investigated the influence of the start-up founder's social competence on the start-up's access to funding sources and performance through the mediating role of the type of social network. This study aimed to examine two types of social networks empirically (i.e., personal networks and business networks) as social capital in analyzing the effect of the founder's social competence and social capital on the method of accessing funding sources. A self-report questionnaire was administered to 252 South Korean start-up founders whose businesses are based in South Korea. Path analysis and mediation effect analysis were performed by structural equation modeling(SEM) using STATA 16.1. This study examined the full mediating effect of the founder's social competence on his/her personal and business networks, respectively, and how the effect leads to different methods to approach funding sources. This is the first study in South Korea to analyze empirically how social competence has contrasting effects on personal and business networks as well as how each type of network varies in its influence on the method founders use to attract investment. This study is also significant in that it proposed a new methodology by utilizing the position generator as the measure of personal and business networks to analyze social networks in detail. The analyses of 252 survey data collected over a period of six months will be a valuable resource that may provide researchers, founders, investors, and other stakeholders in the start-up ecosystem with meaningful implications.

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.47-67
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• 2021

The purpose of this study is to identify antecedent factors influencing the two-sided consumption intention tendencies observed in MZ generation from the viewpoint of consumption value in the cosmetic consumption scene of fashion houses. In order to verify the research model and hypotheses proposed in this study at the level of statistical significance. a survey was conducted for MZ generation, and data collected from a total of 286 samples were analyzed through a structural equation model. As a result. emotional and social consumption value was identified as a variable that had a great influence on the consumption intention of MZ generation. First, self-esteem had an effect on the emotion consumption value at the statistical significance level. Second, materialism had a significant influence on emotional and social consumption values. Third, public self-consciousness was found to have an effect on social consumption value. That is, MZ generation pursues the beauty trend presented by the fashion house's beauty brand and perceives it as a high consumption value. In addition, it was confirmed that MZ generation exhibited a conspicuous consumption tendency that they could be socially differentiated by using fashion house cosmetics.

• Journal of Korean Library and Information Science Society
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• v.52 no.1
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• pp.155-178
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• 2021

In the era of the 4th industrial revolution, public libraries need a strategy for promoting intelligent library services in order to actively respond to changes in the external environment such as artificial intelligence. Therefore, in this study, based on the concept of artificial intelligence and analysis of domestic and foreign artificial intelligence related trends, policies, and cases, we proposed the future direction of introduction and development of artificial intelligence services in the library. Currently, the library operates a reference information service that automatically provides answers through the introduction of artificial intelligence technologies such as deep learning and natural language processing, and develops a big data-based AI book recommendation and automatic book inspection system to increase business utilization and provide customized services for users. Has been provided. In the field of companies and industries, regardless of domestic and overseas, we are developing and servicing technologies based on autonomous driving using artificial intelligence, personal customization, etc., and providing optimal results by self-learning information using deep learning. It is developed in the form of an equation. Accordingly, in the future, libraries will utilize artificial intelligence to recommend personalized books based on the user's usage records, recommend reading and culture programs, and introduce real-time delivery services through transport methods such as autonomous drones and cars in the case of book delivery service. Service development should be promoted.

• Journal of Korea Water Resources Association
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• v.54 no.11
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• pp.985-998
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• 2021

In general, the upstream dam changes downstream flow regime dramatically, i.e., from natural flow regime to hydropeaking flows. This study investigates the impact of the natural flow pattern on downstream fish habitat in a regulated river in Korea using the physical habitat simulation. The study area is a 13.4 km long reach of the Geum-gang River, located downstream from the Yongdam Dam, Korea. A field monitoring revealed that three fish species are dominant, namely Zacco platypus, Coreoleuciscus splendidus, and Opsariichthys bidens, and they account for 70% of the total fish community. Specially, Opsariichthys bidens is an indigenous species in the Geum-gang River. The three fish species are selected as target fish species for the physical habitat simulation. The Nays2D model, a 2D shallow water equation solver, and the HSI (Habitat Suitability Index) model are used for hydraulic and habitat simulations, respectively. To assess the impact of the natural flow pattern, this study uses the annual natural flow regime and hydropeaking flows from the dam. It is found that the natural flow regime increases significantly the Composite Suitability Index (CSI) in the study reach. Then, using the Building Block Approach (BBA), the scenarios for the modifying dam operations are presented in the study reach. Both Scenario 1 and scenario 2 are proposed by using the hydrological method considering both magnitude and duration of the inflow and averaging the inflow over each month, respectively. It is revealed that the natural flow regime embodied in scenario 1 and scenario 2 increases the Weighted Usable Area (WUA) significantly, compared to the hydropeaking flows. In conclusion, the modifying the dam operations by restoring to the natural flow pattern is advantageous to fish community.