• Journal of Engineering Education Research
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• v.25 no.4
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• pp.21-34
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• 2022

This study is conducted with the aim of identify the factors constituting learning competencies for engineering college students, and developing and validating the scale to measure them. To this end, literature and prior research were reviewed and focus group interview was conducted with high-achieving learners of K University in the capital region of Korea. According to previous research, 3 learning competency groups, 12 learning competencies and 41 sub-competencies were derived. Delphi survey was carried out twice, 28 sub-competencies were derived among the 41 sub-competencies through this process. 166 initial items were developed through literature review and FGI. Then, 130 items were confirmed by verifying content validity in the second Delphi survey. Based on this, pilot test were performed with 110 students in K university, and an interview was conducted with 50 students who participated in the pilot test. Reflecting the pilot test results, 1 sub-competency and 22 items were deleted. After the confirmed pilot test results, the main test were performed with all current students in K University. According to the main test result, the validity of the scale and the model fit was verified for the response data of 823 students, and the scale consisting of a total of 105 items was confirmed. The final learning competencies scale included three competency groups and 10 learning competencies. The scale developed in this study can be used as an independent scale for each competency group as needed. It is expected that this scale can be contributed to support the development their learning competencies for academic success of engineering college students, who are future learners.

• Structural Engineering and Mechanics
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• v.90 no.5
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• pp.447-458
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• 2024

This study investigated the influence of scale ratio and vertical load on the seismic performance of Puzuo joints in traditional Chinese timber structures. Three low-cyclic reversed loading tests were conducted on three scaled specimens of Bujian Puzuo in Yingxian Wooden Pagoda. This study focused on the deformation patterns and analyzed seismic performance under varying scale ratios and vertical loads. The results indicated that the slip and rotational deformations of Bujian Puzuo were the primary deformations. The scale of the specimen did not affect the layer where the maximum interlayer slip occurred, but it did decrease the proportion of slip deformation. Conversely, the reducing vertical load caused the layer with the maximum slippage and the position of the damaged Dou components to shift upward, and the proportion of slip deformation increased. When the vertical load was decreased by 3.7 times, the maximum horizontal bearing capacity under positive and negative loadings, initial stiffness, and energy dissipation of the specimen decreased by approximately 60%, 58.79%, 69.62%, and 57.93%, respectively. The horizontal bearing capacity under positive loading and energy dissipation of the specimen increased by 35.63% and 131.54%, when the specimen scale was doubled and the vertical load was increased by 15 times.

• Journal of the Korean Society for Precision Engineering
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• v.8 no.3
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• pp.82-92
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• 1991

A study on the manufacturing of High Precision Linear Scalr using He-Ne Laser interference Of late, along with the advancement of precision machining technology, the requirement of super precision measurement increases as time goes on, and the accuracy of standard scale which is a basis of precision measurement has been cognized as a criterion of industrial development in a nationl. In this paper, we described on technology by which we could carve scale lines thru optical method under the condition of laboratory by using the coherence of He-Ne two-mode stabilized laser and in turn, put it to practical use as linear scale for the measurement of length. Hence in this research in the case of setting scale interval to 20 ${\mu}m$, we employed super precision scale-carving device associated with Ar laser and acousto optic modulator in lieu of flashing lamp scale-carving device, and we obtained as experimental result superior linear scales carved within the accuracy of ${\pm}$0.3${\mu}m$.

• Wind and Structures
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• v.36 no.6
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• pp.367-377
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• 2023

This study proposes a few-shot learning model for extrapolating the wind pressure of scaled experiments to full-scale measurements. The proposed ML model can use scaled experimental data and a few full-scale tests to accurately predict the remaining full-scale data points (for new specimens). This model focuses on extrapolating the prediction to different scales while existing approaches are not capable of accurately extrapolating from scaled data to full-scale data in the wind engineering domain. Also, the scaling issue observed in wind tunnel tests can be partially resolved via the proposed approach. The proposed model obtained a low mean-squared error and a high coefficient of determination for the mean and standard deviation wind pressure coefficients of the full-scale dataset. A parametric study is carried out to investigate the influence of the number of selected shots. This technique is the first of its kind as it is the first time an ML model has been used in the wind engineering field to deal with extrapolation in wind performance prediction. With the advantages of the few-shot learning model, physical wind tunnel experiments can be reduced to a great extent. The few-shot learning model yields a robust, efficient, and accurate alternative to extrapolating the prediction performance of structures from various model scales to full-scale.

• Journal of Engineering Education Research
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• v.21 no.5
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• pp.32-39
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• 2018

The purpose of this study was to develop and validate a behaviorally anchored rating scale for peer evaluation in group projects based on social interdependence theory. A mixed method involving a qualitative and quantitative approach was used in this study. In the qualitative study, both the individual and group interviews were conducted to college students regarding their cooperative learning experiences. Data from this qualitative research was analyzed based on 5 elements of cooperative learning and 'critical incidents' were extracted from students' own voices that would serve as specific rating criteria in the scale. Once the 'critical incidents' have been incorporated into the scale, validation from 3 independent experts was conducted. In the quantitative study, correlations with relevant variables were analyzed to examine the criteria-referenced validity. Findings suggest that the behaviorally anchored rating scale for peer evaluation in group projects can be used in various team-based learning contexts.

• Journal of the Korean Applied Science and Technology
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• v.26 no.4
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• pp.434-439
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• 2009

This paper is a new method for prevent. The particulate scale. stero-microscope were used for the scale removal experiment to improve mineralogical characteristics and the reduction of scales in heat pipe. Generally, the scale in the heat pipe consists of calcium carbonate minerals, such as calcite and aragonite which are precipitated by the reaction of Ca and $CO_2$ in the water. Copper alloy metal could eliminate the scale and prevent the production of scale in the heat pipe.

• Corrosion Science and Technology
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• v.4 no.3
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• pp.89-94
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• 2005

This paper presents the results of a study that was undertaken to optimize the ratio of the components of a new multi-component inhibitor blend composed of orthophosphate/ phosphonates/ acrylate copolymer/ isothiazolone. The effects of newly developed inhibitor on carbon steel dissolution in synthetic cooling water were studied through weight loss tests, electrochemical tests, scale tests, and micro-organism tests. The obtained results were compared to blank (uninhibited specimen) and showed that developed inhibitor revealed very good corrosion, scale, and micro-organism inhibition simultaneously. All measurements indicated that the efficiency of the blended mixture exceeded 90 %. The inhibitive effects arose from formation of protective films which might contain calcium phosphate, calcium phosphonate, and iron oxide. The nature of protective films formed on the carbon steel was studied by scanning electron microscopy (SEM) and auger electron spe ctroscopy (AES). Inhibitor used in this study appeared to have better performance for scale inhibition due to their superior crystal modification effect and excellent calcium carbonate scale inhibition properties. The effect of inhibitor on microorganisms was evaluated through minimum inhibitory concentration (MIC) test. All kinds of micro-organisms used in this study were inhibited under 78ppm concentration of inhibitor.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.6
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• pp.577-585
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• 2015

We fabricated multi-scale such as macro-, micro-, and multi-scale wrinkles by using repetitive volume dividing (RVD) method and thermal curing process. Also wrinkle surface was modified with coating of a self-assembled monolayer (SAM). We measured the contact angle of each wrinkled surface, and observed the behavior of droplets on sloping surface. Through experimental study, we found out that the contact angle was much higher in case of multi-scale and SAM coated wrinkles. And micro-scale wrinkle showed a high contact angle comparing with that of macro-scale wrinkle. Dynamic behaviors of a water droplet like sliding velocity on diverse wrinkled surfaces were dependent on their static contact angles. These results showed that hydro-dynamic characteristics were changed depending on the wrinkle structure and the material forming the wrinkle. These dynamic characteristics can be utilized in bio-chip, microfluidics, and many others in order to control easily chemical reactivity.

• Fire Science and Engineering
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• v.13 no.4
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• pp.30-37
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• 1999

In this study, reduced-scale experiments as the alternative to a real-scale fire test were conducted to understand fire properties in atrium space. The scaling laws were derived from $\pi$-parameters which were deduced by dimensional analysis of governing equations (continuity, conservation of momentum and conservation energy). The 1/50 scale experiment simulated the real-scale fire test in SIVANS atrium at Japan were conducted under the scaling laws. And this results were compared with real-scale experiment results. Furthermore these results were visualized by video recording system using laser light sheet.

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.54-67
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• 2018

There have been recent efforts to establish methods for high-fidelity and multi-physics simulation with coupled thermal-hydraulic (T/H) and neutronics codes for the entire core of a light water reactor under accident conditions. Considering the computing power necessary for a pin-by-pin analysis of the entire core, subchannel-scale T/H analysis is considered appropriate to achieve acceptable accuracy in an optimal computational time. In the present study, the applicability of in-house code CUPID of the Korea Atomic Energy Research Institute was extended to the subchannel-scale T/H analysis. CUPID is a component-scale T/H analysis code, which uses three-dimensional two-fluid models with various closure models and incorporates a highly parallelized numerical solver. In this study, key models required for a subchannel-scale T/H analysis were implemented in CUPID. Afterward, the code was validated against four subchannel experiments under unheated and heated single-phase incompressible flow conditions. Thereafter, a subchannel-scale T/H analysis of the entire core for an Advanced Power Reactor 1400 reactor core was carried out. For the high-fidelity simulation, detailed geometrical features and individual rod power distributions were considered in this demonstration. In this study, CUPID shows its capability of reproducing key phenomena in a subchannel and dealing with the subchannel-scale whole core T/H analysis.