• Journal of computational fluids engineering
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• v.17 no.4
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• pp.32-40
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• 2012

Efficient Global Optimization (EGO) method is a global optimization technique which can select the next sample point automatically by infill sampling criteria (ISC) and search for the global minimum with less samples than what the conventional global optimization method needs. ISC function consists of the predictor and mean square error (MSE) provided from the kriging model which is a stochastic metamodel. Also the constrained EGO method can minimize the objective function dealing with the constraints under EGO concept. In this study the constrained EGO method applied to the RAE2822 airfoil shape design formulated with the constraint. But the noisy CFD data caused the kriging model to fail to depict the true function. The distorted kriging model would make the EGO deviate from the correct search. This distortion of kriging model can be handled with the interpolation(p=free) kriging model. With the interpolation(p=free) kriging model, however, the search of EGO solution was stalled in the narrow feasible region without the chance to update the objective and constraint functions. Then the accuracy of EGO solution was not good enough. So the three-step search method was proposed to obtain the accurate global minimum as well as prevent from the distortion of kriging model for the noisy constrained CFD problem.

• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.177-187
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• 2013

Association rule mining is a popular data mining technique with a wide range of application domains, and aims to extract the cause-and-effect relations between the discrete items included in transaction data. However, analysts sometimes have trouble in interpreting and using the plethora of association rules extracted from a large amount of data. To address this problem, this paper aims to propose a novel approach called HTM for extracting the interesting association rules from given transaction data. The HTM approach consists of three main steps, hierarchical clustering, table-view, and mosaic plot, and each step provides the analysts with appropriate visual representation. For illustration, we applied our approach for analyzing the mass health examination data, and the result of this experiment reveals that the HTM approach help the analysts to find the interesting association rules in more effective way.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.04a
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• pp.175-182
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• 1998

The object of this study is shape finding and cutting pattern generation of membrane structures under the following assumptions : (1) material is linearly elastic (2) stress state is plane stress. Cable and membrane structures should introduce the nonlinear analysis considering geometric nonlinearity because these structures deform largely under the external loads. The analysis procedure is consisted of three steps considering geometric nonlinearity unlike any other structures. First step is the shape finding analysis to determine the initial equilibrium shape. Second step is the stress-deformation analysis to investigate the behaviors of structures under various external loads. Once a satisfactory shape has been found, a cutting pattern based on the shape finding analysis may be generated from the view point of construction. In this paper, (1) shape finding analysis formulation and an example, (2) cutting pattern determination procedure using weighted least-square minimization flattening method and some results are presented.

• Journal of Educational Research in Mathematics
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• v.20 no.1
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• pp.85-102
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• 2010

Linear programming(LP) is useful for finding the best way in a given condition for some list of requirements represented as linear equations. This study analysed LP in mathematics contexts and LP in school mathematics contexts, considered learning process of LP from an epistemological point of view, and explored a hypothetical learning trajectory of LP. The differences between mathematics contexts and school mathematics contexts are whether they considered that the convex polytope $\Omega$ is feasible/infeasible or bounded/unbounded or not, and whether they prove the theorem that the optimum is always attained at a vertex of the polyhedronor not. And there is a possibility that students could not understand what is maximum and minimum of a linear function when the domain of the function is limited. By considering these three aspects, we constructed hypothetical learning trajectory consisted of 4 steps. The first step is to see a given linear expression as linear function, the second step is to partition a given domain by straight lines, the third step is to construct the conception of y-intercept by relating lines and the range of k, and the forth step is to identify whether there exists the optimum in a given domain or not.

• Journal of The Korean Association For Science Education
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• v.34 no.5
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• pp.511-521
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• 2014

In this study, we conducted an exploratory investigation of the imaginative writing processes of middle school students. Twelve 8th graders were asked to imagine and write about the daily life of atoms, assuming that they became specific atoms for themselves. The think-aloud method was used to investigate students' writing processes. We recorded students' writing processes, and also collected the data through interviews to clarify ambiguities in their writing processes. The analyses of the results revealed that their imaginative writing processes could be classified into the three types by the two aspects of writing process components (retrieving information and generating ideas). That is, the integration of retrieving information and generating ideas, the predominant retrieving information, and the predominant generating ideas. The students who were classified into the type of the integration of retrieving information and generating ideas came up with a story and properly introduced science concepts into it. These suggested that this type of students expressed their own understanding more effectively, and that this type was most appropriate for imaginative writing in learning science. The results also showed that the imaginative writing processes were greatly influenced by whether the planning step was adequately considered or not. On the bases of the results, we suggest the teaching strategies for effective imaginative writing in learning science.

• Journal of The Korean Association of Information Education
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• v.23 no.6
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• pp.561-571
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• 2019

Programming education generally includes problem analysis process, automation through algorithms and programming, and generalization process. It is a good software education method for students in improving computing thinking. However, it was found that beginners had difficulties in understanding instruction usage, writing algorithms, and implementing programming. In this study, we developed a game programming education model and curriculum for programming education of pre-service teachers. The 4E model consisted of empathy, exploration, engagement and evaluation. In addition, it is configured to learn game core elements and core command blocks by each stage. To help the pre-service teachers understand the use of various programming blocks, a three-step teaching and learning method was presented, consisting of example learning, self-game creation, and team-based projects. As a result of applying and verifying the curriculum for 15 weeks, it showed significant results in the 4E model and pre-service teachers' perception of block programming competence and the level of computational thinking on the submitted game project results was also high.

• Journal of Life Science
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• v.22 no.4
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• pp.552-558
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• 2012

Severe acute respiratory syndrome (SARS) is a severe respiratory infectious disease caused by a novel human coronavirus, SARS-CoV. The 3CL protease is a key enzyme in the proteolytic processing of replicase polyprotein precursors, pp1a and pp1ab, which mediate all the functions required for viral genomic replication and transcription. Therefore, this enzyme is a target for the development of chemotherapeutic agents against SARS. A large quantity of active SARS-3CL protease is required for development of anti-SARS agents. Here we have constructed overexpression vector for the production of the SARS-3CL protease. The gene encoding SARS-3CL protease was amplified using polymerase chain reaction and cloned into the pET29a expression vector, resulting in pET29a/SARS-3CLP. Recombinant SARS-3CL protease was successfully synthesized by the dialysis mode of the cell-free protein expression system, and purified by three-step fast protein liquid chromatography using HighQ and MonoP column chromatographies and Sephacryl S-300 gel filtration. In addition, the produced SARS-3CL protease was found to be an active mature form. This study provides efficient methods not only for the development of anti-SARS materials from natural sources, but also for the study of basic properties of the SARS-3CL protease.

• Journal of Science Education
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• v.46 no.2
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• pp.195-211
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• 2022

In this study, we explored the meaning of astronomical observation activities of five earth science teachers through in-depth interviews. Semi-structured interviews were conducted after providing a questionnaire based on Seidman's three-step process of interview. By analyzing the interview transcript, the educational implications inherent in astronomical observation activities were extracted. Teachers have constructed systematic basis of observation and astronomy in the observational astronomy and laboratory class during their course in the teacher education institute. After they became in-service teachers, practical know-hows of astronomical observation activities in schools were developed with the help of colleagues. By designing and executing astronomical observation activities for students, teachers notice positive changes in the cognitive domain, affective domain, and career perception of the students. Hence, teachers consider that astronomical observation activities have great educational effects. In addition, astronomical activities appear to be very rewarding and satisfying experiences to teachers, by providing opportunities for having pride as an earth science teacher. However, teachers tend to find difficulties in operating astronomical observation activities in fields, due to both internal and external obstacles. It is found that the removal of internal obstacles is more important for teachers to attempt or to continue astronomical observation activities. In this sense, it is necessary to support teachers by providing timely training courses with related content, as well as opportunities to share their experiences within a peer group such as teachers' research society.