• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.519-524
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• 2023

The purpose of this study is to construct basic data for efficient technical training by investigating the difference in muscle activity during badminton technical movements involving jump motions similar to game situations. Seven male badminton players were randomly assigned to perform smash, drop, and clear techniques, and electromyograms were measured during the implementation of three technical movements. Measured EMG was calculated by RMS and one-way ANOVA was performed. The muscle activity of the smashing motion did not show any significant difference according to the site. In drop motion, activity of PM in the upper extremity muscles was lower than that of BC and ECR, and FCR activity was lower than that of EC. The activity of ECR was higher than that of PM and FCR. The activity of ES in trunk muscles was lower than that of RF and GM. RF activity of lower extremity muscles was higher than that of ES and BF. In clear motion, the activity of TC in upper extremity muscle was higher than FCR. The activity of ES in trunk muscles was lower than that of BF. RF activity of lower extremity muscles was higher than that of BF, and BF activity was lower than that of RF and GM. The activity of GM was higher than that of BF. As for muscle activity according to badminton skills, smash and drop motions were higher than clear motions in FCR, and clear motions were higher than smash and drop motions in RA. In conclusion, it is considered that muscle activity during the badminton game is different according to the characteristics of each skill, and FCR can affect the smash and drop, and RA can affect the clear motion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4D
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• pp.467-472
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• 2009

Even if Seoul City administration improved its public transportation service, transportation model share in seoul has not been increased. Subway user is also decreasing. Therefore, policy transition into TOD(Transit Oriented Development) should be applied in oder to enhance subway modal share. This paper develops a influencing model by using variables of transportation demand and supply. In addition, it provides major influencing factors for users in subway station area and level of transportation supply based on the analysis results. The results show that: first, cluster analysis presents that traffic pattern is proved to be different according to land use characteristics(residence, non-residence); second, main transportation variables such as transferring distance, the number of bus stop, the number of short distant bus lines, and the number of bicycle are more supplied in residential area compared to non-residential areas; third, the number of lines, bus dispatching interval, operating time, and distance between subway stations are more supplied in non-residential areas than residential areas. All in all, the results will be useful for providing priority of considerations in case of decision-making on public transportation policy in subway station area.

• Korean Journal of Legislative Studies
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• v.27 no.2
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• pp.71-109
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• 2021

The purpose of this study is to find out what factors influence lawmakers' voting decisions in the plenary session. In particular, the study examines causes and characteristics of waffling and strategic waffling, which express opposition or abstention in a discharge petition or a vote at the plenary session despite participating in a bill sponsorship. The study on waffling is meaningful because it has not been covered in previous literatures. To this end, the Gadeokdo New Airport Special Act, which the National Assembly passed in February 2021, was set as an analysis target. The study examined the factors that affected legislators' voting decisions and participation in bill sponsorship and who were related with waffling. Statistical results showed that the age variable influenced the motion of the bill while seniority and party affiliation had an effect on the participation of the bill. Likewise, the study found that party affiliation and district had an influence on the approval of the bill. In addition, the analysis of waffling showed that lawmakers with higher seniority tended not to participate in the vote. It could be interpreted that lawmakers with more legislative experience judged that they would benefit from strategic waffling. There is a limit to understanding lawmakers' decision-making and waffling through a limited analysis of the Gadeokdo New Airport bill. However, given that lawmakers tend to choose avoidance strategies in ambiguous situations, and given the high intelligence of lawmakers who know better than anyone about the future impact of a new bill, the decision-making shown by lawmakers in each stage of the situation is a prudent judgment gained from their experience. It indicates that it is necessary to research the legislative activities of lawmakers in various ways.

• Korean Journal of Exercise Nutrition
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• v.13 no.1
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• pp.15-21
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• 2009

Ergogenic aids are substances, devices, and practices that enhance an individual's energy use and production, and recovery from fatigue. L-carnitine increases enhance performance and aerobic capacity by stimulating lipid oxidation in muscle cells during long term exercise. L-carnitine is a well known and widely used ergogenic aid. In the present study, the effect of L-carnitine at concentrations of 100 nM, 1 μM, 10 μM, and 100 μM on the amplitude of field potential in rat cardiac muscle slices was measured using multi-channel extracellular recording (MED 64) system. In the present result, L-carnitine was shown to enhance field potential as a does-dependent manner. The increasing effect of the L-carnitine on field potential was not affected by application of the glibenclamide, an ATP-dependant K⁺ channel antagonist. The increasing effect of L-carnitine on field potential was suppressed by application of the diazoxide, an ATP-dependent K⁺ channel agonist. Present data show that L-carnitine potentiates field potentials by inhibition on ATP-dependant K⁺ channel in cardiac muscles. The enhancing effect of the L-carnitine on the field potential in cardiac muscles can be suggested as one of the underlying mechanism of ergogenic aid of the L-carnitine.

• Journal of Practical Engineering Education
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• v.15 no.1
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• pp.73-80
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• 2023

The advancement of online technology in the 21st century has increased online courses and web-based communication in higher education. This type of education is not limited by time or location and has made it possible to expand university campuses globally and broaden the reach of university education to the general public and students from other universities. Changes such as a decrease in the school-age population and a reorganization of the university structure have also created an opportunity to change the perception of online education. In this paper, we conducted surveys on K University students, high school seniors, and the general public to assess their satisfaction with online courses, identify areas that require massive online courses, and determine students' needs for the operation of massive online courses. The survey showed that K University students are generally satisfied with online courses. However, improvements are needed to ensure a smooth online course-taking environment, increase system uniformity, and enhance the overall online course environment. High school students have a strong preference for natural science and should be offered online courses in subjects such as mathematics and physics as prerequisites to prepare for their major classes. The general public prefers the humanities, which is evident in the purpose of the liberal arts lectures.

• Journal of The Korean Association For Science Education
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• v.43 no.6
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• pp.563-572
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• 2023

This study aimed to analyze cases of online class design by pre-service science teachers to identify the teaching strategies employed for online classes. For this purpose, the real-time online class lesson plans of 12 pre-service science teachers, who had experienced education utilizing online teaching tools for a semester, were collected and analyzed. The pre-service science teachers considered all the elements that were essential in traditional face-to-face class designs, including prerequisites, statements of learning objectives, stimulating motivation, teaching and learning methods, wrapping up, teacher-student interaction, and assessment. They devised teaching strategies that could overcome the limitations of online teaching and were not feasible in face-to-face classes for each element. Additionally, they were considering new instructional strategies tailored to the online teaching environment, such as creating a conducive environment for using online teaching tools and strategies related to checking the online teaching environment. However, for statements of learning objectives, stimulating motivation, and wrapping up, most of the pre-service science teachers predominantly utilized teaching strategies from traditional face-to-face classes, especially those involving the presentation of visual materials through online tools. Student-centered approaches were rarely implemented in stimulating motivation or wrapping up. These findings imply that one semester of exposure to the utilization of online teaching tools may be insufficient in teacher education. Thus, there is a need for a continuous and expanded educational program on the utilization of online teaching tools as part of pre-service teacher education.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.950-957
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• 2023

For safe mooring and towing between the ship and port, the equipment must be designed in accordance with the relevant international regulations. However, some small shipyards and engineering companies often do not fully comprehend the core contents. Therefore, the international regulations regarding towing and mooring equipment are reviewed and the bollard and chock are newly developed based on the Mooring Equipment Guideline 4 (MEG4) standards. A bollard is a mooring equipment used to fix a mooring rope to the hull. It has two columns and is mostly used in a figure eight pattern knots under the mooring condition. The chock, which is used to change the mooring rope direction coming into the ship from outside, is manufactured using a casting with curvature. The two mooring equipment are widely used in the stern, bow, and mid-side. Owing to the increase in the size of container vessels and LNG ships, the mooring rope load has increased and the safe working load of the mooring equipment must be revised. This study summarizes and examines the results of the allowable stress method obtained using finite element analysis modelling. To consider the mesh size effect, a reasonable criteria was suggested by referring the existing class guidance. Additionally, the safe working load was verified through nonlinear collapse analysis, and the elastic region against load increments was confirmed. Furthermore, the proposed evaluation method can be used to develop similar equipment in the near future.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.681-687
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• 2023

The selection technique for optimal operation position selection technique is used to present the initial bow and stern draft with minimum resistance, for achievingthat is, the optimal fuel consumption efficiency at a given operating displacement and speed. The main purpose of this studypaper is to develop a program to select the optimal operating position with maximum energy efficiency under given operating conditions based on the effective power data of the target ship. This program was written as a Python-based GUI (Graphic User Interface) usingbased on artificial intelligence techniques sucho that ship owners could easily use the GUIit. In the process, tThe introduction of the target ship, the collection of effective power data through computational fluid dynamics (CFD), the learning method of the effective power model using deep learning, and the program for presenting the optimal operation position using the deep neural network (DNN) model were specifically explained. Ships are loaded and unloaded for each operation, which changes the cargo load and changes the displacement. The shipowners wants to know the optimal operating position with minimum resistance, that is, maximum energy efficiency, according to the given speed of each displacement. The developed GUI can be installed on the ship's tablet PC and application and used to determineselect the optimal operating position.

• Education of Primary School Mathematics
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• v.26 no.4
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• pp.299-316
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• 2023

With the importance and necessity of using AI in the field of education, this study aims to explore elementary school teachers' perceptions of using Artificial Intelligence (AI) in mathematics education. For this purpose, we conducted a survey using a 5-point Likert scale with 161 elementary school teachers and analyzed their perceptions of mathematics education with AI via four categories (i.e., Attitude of using AI, AI for teaching mathematics, AI for learning mathematics, and AI for assessing mathematics performance). As a result, elementary school teachers displayed positive perceptions of the usefulness of AI applications to teaching, learning, and assessment of mathematics. Specifically, they strongly agreed that AI could assist personalized teaching and learning, supplement prerequisite learning, and analyze the results of assessment. They also agreed that AI in mathematics education would not replace the teacher's role. The results of this study also showed that the teachers exhibited diverse perceptions ranging from negative to neutral to positive. The teachers reported that they were less confident and prepared to teach mathematics using AI, with significant differences in their perceptions depending on whether they enacted mathematics lessons with AI or received professional training courses related to AI. We discuss the implications for the role of teachers and pedagogical supports to effectively utilize AI in mathematics education.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.305-314
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• 2023

In this study, a mathematical model of a 9.77 G/T small fishing vessel was established based on captive model tests. The powering and manoeuvring performances of the vessel in the harbor and coastal sea were focused on, so captive model tests were conducted up to the full-scale speed of 8 knots. Propeller open water, resistance, and self-propulsion tests of a 1/3.5-scaled model ship were performed in a towing tank, and the full-scale powering performance was predicted. Hydrodynamic coefficients in the mathematical model were obtained by rudder open water, horizontal planar motion mechanism tests of the same model ship. In particular, in static drift and pure yaw tests which were conducted at a speed of 2 to 8 knots, the linear hydrodynamic coefficients varied with the ship speed. The effect of the ship speed on the linear coefficients was considered in the mathematical model, and manoeuvring motions, such as turning circles and zig-zags, were simulated with various approach speeds and analyzed.