• International Journal of Concrete Structures and Materials
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• v.7 no.3
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• pp.225-238
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• 2013

In this study, a two-layer feed-forward neural network was constructed and applied to determine a mapping associating mix design and testing factors of cement-nano silica (NS)-rice husk ash ternary blended concrete samples with their performance in conductance to the water absorption properties. To generate data for the neural network model (NNM), a total of 174 field cores from 58 different mixes at three ages were tested in the laboratory for each of percentage, velocity and coefficient of water absorption and mix volumetric properties. The significant factors (six items) that affect the permeability properties of ternary blended concrete were identified by experimental studies which were: (1) percentage of cement; (2) content of rice husk ash; (3) percentage of 15 nm of $SiO_2$ particles; (4) content of NS particles with average size of 80 nm; (5) effect of curing medium and (6) curing time. The mentioned significant factors were then used to define the domain of a neural network which was trained based on the Levenberg-Marquardt back propagation algorithm using Matlab software. Excellent agreement was observed between simulation and laboratory data. It is believed that the novel developed NNM with three outputs will be a useful tool in the study of the permeability properties of ternary blended concrete and its maintenance.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.5
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• pp.173-185
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• 2016

As a dual-degree program/exchange student program becomes widespread, the faculty and students consisting of a course are being globalized. Recently, there has been an online or blended learning-based course, which is evolved from a conventional offline course. However, the course has no consideration of a dual-degree program or exchange student program because it is limited to a domestic university. To create and manage a global course, there have several of difficulties in the aspects of cost or effectiveness. As a solution to tackle them, it is necessary to do research on providing blended global courses with a fusion approach of online and offline. In this paper, we studied and presented a model of blended global courses. To create and maintain overseas scholar-oriented courses, we devised eight types of blended global courses depedning on their opening time and the cooperative relation between online and offline and made their comparative analysis. The blended global course proposed in this paper can be applied to cultivating global human resources in universities.

• Journal of Information Technology Services
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• v.10 no.3
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• pp.61-76
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• 2011

The purpose of this paper was to design and implement effective learning model for internet ethics education, following the learning principle and procedure of PBL(Problem-Based Learning) which is one of the constructivism teaching-learning theories(, and to apply it). In this learning model, online learning and face-to-face classes were systematically combined for achieving the teaching-learning goals and the main module for online learning run on Moodle, an open source LMS(Learning Management System). It is possible for learner to participate actively in creation of micro-contents and reorganize contents using various SNS(Social Network Service). The learner can achieve the learner-oriented learning and select micro-contents in order to reorganize the personalized learning contents to take advantage of SNS among learners. To examine educational effectiveness of the proposed learning model, an experimental study was conducted through the education content and method to the subjects of two classes in the second-grade of university located in OO city. 60 students(treatment group=30, control group=30) participated in the experiment. The result statistically verified that the proposed learning method is more effective in cultivating consciousness of internet ethics than the face-to-face PBL learning method. The results of this paper also showed that a lecture using blended learning is efficient in achieving learning performance and that learners responded positively(, which are indicating that the higher effectiveness of learning would be expected) by forming connectedness among learners using SNS. The results of this paper showed that a lecture using blended learning is effectiveness in achieving learning performance and that learners responded positively, which are indicating that the higher effectiveness of learning would be expected by forming connectedness among learners using SNS.

• Journal of the Korean Society for Library and Information Science
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• v.55 no.2
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• pp.179-200
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• 2021

This study is aimed at analyzing cases of management focusing on a reading club using the blended learning at school library and the relevant programs of the free semester system. Therefore, the study has designed a research model for the blended-based management of school libraries, and cases of activities of reading clubs at school libraries for participants in programs linked with the free semester system have been analyzed. As a result of the analysis, first, the confidence level was satisfied in all areas of stability, consistency, predictability and verification on confidence level for related variables of the research model. Second, a meaningful relation has been verified in the correlation analysis between the blended activities and activities of the career search and the career design. Third, as a meaningful static effect has been shown in the contact-free activities in the areas of activities of the blended learning and activities of the career search and the career design, it was verified that programs linked with reading clubs of the free semester system have higher positive effects in the contact-free activities. Last but not least, programs related to local governments to support reading clubs at school libraries have been presented, and management of the blended learning at school libraries has been suggested.

• The Journal of Korean Association of Computer Education
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• v.11 no.6
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• pp.11-27
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• 2008

Though web-based learning is known to be effective for computer aided practical class, it lacks in cooperative human feedback and self-adjustment. This paper presented the effects of blended learning that was based on web-based learning for learning by level and blended with peer tutoring for reducing the differentials of scholastic achievements between the students. For experimental purpose, high school students were divided into two groups and web-based EXCEL tutoring tool was developed and applied to both groups in advance. After this learning, we applied the web-based learning for comparative group as before and peer tutoring for experimental group respectively, Performance result evaluated by SPSS showed that the Blended Learning has affirmative effect in scholastic achievements. Especially, students under the medium level of experimental group could narrow the gap to the high level students in its group and this eventually improved the overall achievements of experimental group with blended learning.

• Journal of the Korean Statistical Society
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• v.24 no.2
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• pp.349-360
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• 1995

This paper deals with the robustness properties of the minimum disparity estimation in linear regression models. The estimators defined as statistical quantities whcih minimize the blended weight Hellinger distance between a weighted kernel density estimator of the residuals and a smoothed model density of the residuals. It is shown that if the weights of the density estimator are appropriately chosen, the estimates of the regression parameters are robust.

• Computers and Concrete
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• v.13 no.1
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• pp.97-115
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• 2014

Silica fume is a by-product of induction arc furnaces and has long been used as a mineral admixture to produce high-strength, high-performance concrete. Due to the pozzolanic reaction between calcium hydroxide and silica fume, compared with that of Portland cement, the hydration of concrete containing silica fume is much more complex. In this paper, by considering the production of calcium hydroxide in cement hydration and its consumption in the pozzolanic reaction, a numerical model is proposed to simulate the hydration of concrete containing silica fume. The heat evolution rate of silica fume concrete is determined from the contribution of cement hydration and the pozzolanic reaction. Furthermore, the temperature distribution and temperature history in hardening blended concrete are evaluated based on the degree of hydration of the cement and the mineral admixtures. The proposed model is verified through experimental data on concrete with different water-to-cement ratios and mineral admixture substitution ratios.

• Proceedings of the Korea Contents Association Conference
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• 2014.06a
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• pp.399-400
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• 2014

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.6
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• pp.693-704
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• 2017

Blended-Wing-Body Underwater Glider (BWBUG), which has excellent hydrodynamic performance, is a new kind of underwater glider in recent years. In the shape optimization of BWBUG, the lift to drag ratio is often used as the optimization target. However this results in lose of internal space. In this paper, the energy reserve is defined as the direct proportional function of the internal space of BWBUG. A motion model, which relates gliding range to steady gliding motion parameters as well as energy consumption, is established by analyzing the steady-state gliding motion. The maximum gliding range is used as the optimization target instead of the lift to drag ratio to optimizing the shape of BWBUG. The result of optimization shows that the maximum gliding range of initial design is increased by 32.1% though an Efficient Global Optimization (EGO) process.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.6
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• pp.995-1006
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• 2015

Underwater glider, as a new kind of autonomous underwater vehicles, has many merits such as long-range, extended-duration and low costs. The shape of underwater glider is an important factor in determining the hydrodynamic efficiency. In this paper, a high lift to drag ratio configuration, the Blended-Wing-Body (BWB), is used to design a small civilian under water glider. In the parametric geometric model of the BWB underwater glider, the planform is defined with Bezier curve and linear line, and the section is defined with symmetrical airfoil NACA 0012. Computational investigations are carried out to study the hydrodynamic performance of the glider using the commercial Computational Fluid Dynamics (CFD) code Fluent. The Kriging-based genetic algorithm, called Efficient Global Optimization (EGO), is applied to hydrodynamic design optimization. The result demonstrates that the BWB underwater glider has excellent hydrodynamic performance, and the lift to drag ratio of initial design is increased by 7% in the EGO process.