• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.444-453
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• 2017

This paper proposes an operational algorithm for a Photovoltaic Power-Hardware-In-Loop Simulator that is designed to improve the control algorithm and reliability of the PV Inverter. There was an instability problem in the PV PHILS with the conventional algorithm when it was connected tothe PV inverter. Initially, a real-time based computing unit with mathematical modeling of the PV array is implemented and a DC amplifier and an isolated device for DC power measurement are integrated. Several experiments were performed based on theabove concept undercertain conditions, which showed that the proposed algorithm is more effective for the PV characteristic test and grid evaluation test than the conventional method.

• Journal of The Korean Association of Information Education
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• v.19 no.1
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• pp.11-20
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• 2015

The researches on the concept of justice and utilization for Computational Thinking with SW education are being actively discussed. However, a program has developed in conjunction with the actual elementary curriculum is not much. In this study, we have developed an educational program in applied mathematics based on CT. First, a separated view for a CT Application of mathematical concepts and objectives are set in three different application models. In order to achieve the CT-based math lessons, we also have developed a teaching and learning materials. We applied the developed materials in class, and to evaluate the satisfaction of learners. In addition to the validation of school application, we conducted a survey of professionals and teachers. The results of the analysis, the data showed that are helpful in the development of the student' CT ability as well as the ability to be helpful teaching and learning in school.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.121-130
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• 1999

The objective of this study is to perform finite element analyses(FEA) using the anisotropic hardening constitutive model on the basis of the total stress concept. An anisotropic hardening model was then developed to solve the problem and its mathematical formulations and experimental verifications were also described. In a companion paper, the constitutive equation will be formulated for accurate and efficient solutions of FEA, and coded into a nonlinear analysis program, and finally a field problem will be analyzed. The proposed model includes the failure criterion of a von Mises type and the anisotropic hardening rule based on the generalized isotropic hardening description, which can model the nonlinearity and the anisotropy of the stress-strain relationship. As a result this study could verty the experimental results for UU triaxial tests, CU triaxial tests for overconsolidated samples, and anisotropic loading tests with the rotation of principal stress axes for $K_0$consolidated samples.

• Korean Journal of Construction Engineering and Management
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• v.13 no.3
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• pp.43-55
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• 2012

A methodology for BIM Quality Assurance in the construction industry is becoming increasingly an important issue to determine the reliability of BIM. However, the quality assurance of BIM is currently limited to check 3D models, such as clash detection and space layout while verification methods for disciplinary BIM results from structural engineering, mechanical engineering, and estimation do not exist yet. Particularly, in the BIM-based estimation mathematical equations to take off quantities are not clearly exposed so that the results are not quite accepted at practices. With the concept of reliability engineering defined in the manufacturing industry to improve reliability of outcomes of BIM-based quantity take-off, impacting factors that affect reliability of BIM-based quantity take-off were derived. It was found that the factors also include the modeling method and the features of a BIM tool. Therefore, this research aims to propose modeling and verification methods to improve reliability of BIM-based quantity take-off through the pilot test that was performed with commercial BIM tools and IFC-based BIM data.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.4 s.175
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• pp.926-936
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• 2000

Actual and strict definition of the shift quality for the powertrain system equipped an automatic transmission must be understood through the acceleration change of the vehicle body, which the driver directly feels as a shift shock. For this reason, it is necessary to concurrently analyze the characteristics of the powertrain system and the vehicle body. This paper presents the mathematical model of the vehicle body, which is based on the equivalent lumped system, to append to the developed model of the powertrain system. The concept of tire slip is also introduced for the experimental relationship between tire/road and driving force. Using the developed dynamic simulation programs, shift transients characteristics are analyzed. Theoretical results are compared with experimental ones from real car tests in equal conditions in order to prove the validity of presented model. In these tests, the system to measure the vehicle acceleration is used with various speeds and engine throttle sensors. It is expected that the presented modeling techniques can provide good predictions of the vehicle driving comfortability.

• School Mathematics
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• v.19 no.1
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• pp.95-116
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• 2017

Through the teaching experiments, we investigated a series of processes for obtaining the differential coefficient at x=0 of the exponential function $y=2^x$ based on the process of constructing the natural constant e and the understanding of it. and all of the students who participated in this study were students who had no experience of calculating the derivative of the exponential function. The purpose of this study was not to generalize the responses of students but to suggest implications for mathematical concept mapping related to calculus by analyzing various responses of students participating in experiments. It is expected that the accumulation of research data derived in this kind of research on the way of understanding and composition of learners will be an important basic data for presenting the learning model related to calculus.

• Korean Institute of Interior Design Journal
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• v.15 no.5 s.58
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• pp.247-254
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• 2006

The museum has steadily been evolved by time with its function and social idea differently. As the museum makes its evolution, its architecture has also been changed. This study aims to find out the characteristics of museum architecture by applying Space Syntax for space correspondence of museum architecture changed by the time. And the characteristics could be used as project guide by making data for building up museum architecture changed by social concept with efficient and functional system. The method of the study is to divide the museum into three generations, and give case for each generation. And the each chosen case was analyzed by convex space of space syntax. The order of the analysis is to divide the case as the unit space, make out the Convex Map. And finally get the analysis variable by carrying out a mathematical operation. The characteristics found in these operations are as follows. First, the major space has been planed for convenience of spectators. Second, exhibition space located on specific area in entire plot planning makes spectators easy to recognize in terms of the line of flow toward exhibition space and also relieves character of major and exhibition space. Third, it is getting hard to comprehend the entire space as forming diverse space in process that museum accepts many request from spectators.

• Journal of the Korean School Mathematics Society
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• v.12 no.3
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• pp.347-364
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• 2009

In this paper, the researchers investigated the influence of graphing calculator in learning the concept of linear function for the gifted students. Elementary students who were taking a course in enrichment mathematics at Science Education Institute for the Gifted in Mokpo National University were selected for this study. The researchers analyzed students' processes of mathematical inference and conjecture, and students' algebraic description. We found the facts that the visualization using a graphing calculator and CBL is helpful to the gifted students in understanding concepts of liner function, finding the relationship between variables, analyzing and presupposing of graph. But, using graphing calculator can be a factor that disturbs learning of students who have too much of curiosity on graphing calculator.

• Journal of Soil and Groundwater Environment
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• v.8 no.4
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• pp.12-20
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• 2003

This study presents a mathematical model for simulating the fate and transport of a reactive organic contaminant, TCE, degraded by cometabolism in dual-porosity soils during the installation of in situ biobarrier. To investigate the effect of dual-porosity on transport and biodegradation of organic hydrocarbons, a bimodal approach was incorporated into the model. Modified Monod kinetics and a microcolony concept were employed to represent the effects of biodegrading microbes on the transport and biodegradation of an organic contaminant. The effect of permeability reduction in biobarrier due to biomass accumulation on the flow field were examined in the simulation of a hypothetical field-scale in situ bioaugmentation. Simulation results indicate that the presence of the immobile region can decrease the bioavailability of biodegradable contaminants and that the placement of microbes and nutrients injection wells should be considered for an effective installation of biobarrier during in situ bioaugmentation scheme.

• Textile Coloration and Finishing
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• v.21 no.5
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• pp.41-50
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• 2009

Design of experiments (DoE) concept was successfully applied to determine the optimum processing conditions that yield maximum % exhaustion for berberine interaction with synthetic tanning agent pretreated polyamide substrates. The potential of synthetic tanning agent to provide anionic sites on the polyamide for berberine interaction which is cationic in nature was tested to increase the % exhaustion of berberine in this article. Experiments were designed according to Central Composite Rotatable Design (CCRD). The three factors for synthetic tanning agent pretreatment and two factors for berberine interaction each at five different levels, including central and axial points were considered. Experiments were conducted in a laboratory scale infra-red treatment instrument according to CCRD. For each response, second order polynomial models were developed using multiple linear regression analysis incorporating linear, interactions and squared effects of all variables and then optimized. The significance of the mathematical model developed was ascertained using Excel regression (solver) analysis module. Analysis of variance (ANOVA) was performed to check the adequacy and accuracy of the fitted models. The response surfaces and contour maps showing the interaction of process variables were constructed. Applying Monte Carlo simulation, response surface and contour plots, optimum operating conditions were found and at this optimum point, % exhaustion of 81% and 74% respectively for synthetic tanning agent pretreatment and berberine interaction were observed and subsequently the results were experimentally investigated.