• Educational Technology International
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• v.12 no.1
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• pp.1-20
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• 2011

The study described in this paper examined the effectiveness of a multimedia case-based learning environment to teach technology integration to Korean pre-service teachers. The structure and philosophy behind the use of embedded video in an online, multimedia system and the data collected from 103 pre-service teachers are presented and discussed. The overall finding shows that there was no significant difference from pre- to posttest among the lecture, the case-based, and the mixed environment groups. However, low prior knowledge students improved more when they learned about technology integration with the mixed method than with the case-based method alone. Discussion about this result and its educational implications conclude the paper.

• Journal of Science Education
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• v.46 no.1
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• pp.40-52
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• 2022

Daily science classes, which have been continued as part of the spread of participatory science culture, has taken the lead in popularizing science as an effective out-of-school experiential and research activity. However, due to the recent COVID-19 situation, daily science classes have also become an environment in which there is no choice but to switch to non-face-to-face or to combine face-to-face and non-face-to-face education. Therefore, in this study, we examine how elementary school students participating in the non-face-to-face daily science class program change their usual fields of interest, perception of science and technology, interest about science, and scientific competency. In addition, the educational effectiveness of the non-face-to-face daily science class improved by comparing the differences in perceptions of students and parents, and future operation plans were sought. As a result of the study, after participating in the non-face-to-face daily science class program, students' interest in science and technology development, future technology, environmental pollution, and social media increased, and their interest in games decreased. Also, students' interest in science and technology activities, interest in science, and scientific competency also increased. This shows that non-face-to-face daily science class education is effective. Therefore, it was suggested that it is necessary to diversify the learning topics and content levels of the daily science class program, to expand the opportunities of non-face-to-face science education for underprivileged learners, and to develop and share science content using the latest media.

• Journal of Korea Foundry Society
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• v.35 no.2
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• pp.23-28
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• 2015

This work presents the effect of the cooling rate on the precipitation of super duplex stainless steel. Specimens of super duplex stainless steel with a specific composition were cooled at various cooling rates after being melted at $1550^{\circ}C$ in a directional solidification furnace. Ferrite (${\delta}$), Austenite (${\gamma}$), Sigma (${\sigma}$), and Chi (${\chi}$) phases were precipitated when the cooling rate was lower than 0.22 K/s. When the cooling rate was 0.22 K/s or faster, ${\sigma}$ and ${\chi}$ phases were not precipitated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.819-826
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• 2002

In this paper, the performance of Au / $Ba_{0.5}Sr_{0.5}TiO_3$ (BST) / Magnesium oxide (MgO) two-layered electrically tunable band-pass Filters (BPFs) is demonstrated. The devices consist of microstrip, coplanar waveguide (CPW), and conductor-backed coplanar waveguide (CBCPW) structures. These BST thin film band-pass filters have been designed by the 2.5 D field simulator, IE3D, Zeland Inc., and fabricated by thin film process. The simulation results, using the 2-pole microstrip, CPW, and CBCPW band-pass filters, show the center frequencies of 5.89 GHz, 5.88 GHz, and 5.69 GHz, and the corresponding insertion losses are 2.67 dB, 1.14 dB, and 1.60 dB, with 3 %, 9 %, and 7 % bandwidth, respectively. The measurement results show the center frequencies of 6.4 GHz, 6.14 GHz, and 6.04 GHz, and their corresponding insertion losses are 6 dB, 4.41 dB, and 5.41 dB, respectively, without any bias voltage. With the bias voltage of 40 V, the center frequencies for the band-pass filters are measured to be 6.61 GHz, 6.31 GHz, and 6.21 GHz, and their insertion losses are observed to be 7.33 dB, 5.83 dB, and 6.83 dB, respectively. From the experiment, the tuning range for the band-pass filters are determined as about 3 % ~ 8 %.

• Journal of Korean Home Economics Education Association
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• v.19 no.2
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• pp.77-101
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• 2007

The purposes of this study were to develop ICT consumer education program for the second grade middle school students using in the Home Economics and Technology class and to test the effect of this program in terms of learning the knowledge and forming the attitude to be a wise consumer. The contents of a middle school Home Economics curriculum and 10 different textbooks were analyzed. Based on these analyses 5 ICT lesson plans on consumer education were developed. The second grade middle school students as an experimental group participated in 5 ICT consumer education classes during the middle school Home Economics and Technology classes. The control group of students who had same condition with the experimental group were taught by traditional instructional methods. After experiment, the changes in knowledge and attitude to be a wise consumer of both groups were analyzed using Analysis of Covariance. The significant improvements of knowledge and attitude of it were found among the experimental group of students compared with control group of students. Thus the conclusion is that the ICT consumer education program conducted in this study was found to be more effective than traditional one in terms of learning the knowledge and forming the attitude to be a wise consumer.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.2
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• pp.73-78
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• 2004

In this paper, the instrument for scientific education in elementary school is developed with the application of basic robot technology for coming IT future world. Particularly, a kind of robot game to fun a race with each other is planed to give a motive or interest in scientific education. This robot game is played with two robots per player, One robot is moved wirelessly with a remote controller and the other robot is moved automatically with intelligence given by computer program made by a player. This game system will be in spotlight as multi-objective educational system not only to teach basic technology of IT, but also to improve the ability for logical and creative thought in elementary school students.

• Journal of Engineering Education Research
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• v.18 no.6
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• pp.46-51
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• 2015

Recently, Information Communication Technology(ICT) is one of the most important technology that supports the modern society. As the ICT rises, the needs of the nurturing talents, who can develop a service or hardware on the basis of the humanities increases. As a result, teaching programming skills to students studying humanities and social science are essential. Also, it is important to train students studying science and engineering to write their thoughts logically. In order to serve these students, we introduce a pedagogy for computer programming using programming essay. Since a program is a sequence of the operations based on the programmer's logical thinking, programming can be considered as describing programmer's logic in the proper order using programming syntax. In this research, we train students to describe their logic using natural language. Students write down their essays for a given programming problems. Also, we introduce a pedagogy guideline using programming essay.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.601-610
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• 2020

Recently, damage caused by drought is becoming worse and worse due to the global climate change. To overcome these problems, movable-weir to control the water level has been installed instead of a fixed-weir made from concrete. On the other hand, it is difficult to operate an existing moveable-weir because of the high cost of facility management and manpower consumption. In addition, because most moveable-weirs are installed in power systems, the operating cost and the cost of connection for power systems increase when they are located in remote areas. Therefore, this paper proposes an optimal design algorithm and the evaluation algorithm of the SOC (state of charge) of a lithium-ion battery to replace an existing power supply with eco-friendly movable-power with a power supply system using PV modules and lithium-ion batteries. In addition, this study modeled a 50kW power supply system of a movable-weir using PSCAD/EMTDC S/W. The simulation results confirmed that the proposed algorithm has stable operation characteristics in an independent operation mode and interconnection operation mode and that there is the possibility of commercialization with a benefits evaluation of the eco-friendly power supply system of a movable-weir.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.9
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• pp.1093-1098
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• 2013

A single-crystal sapphire is used as a transparent bulletproof window material; however, few studies have investigated the dynamic behavior and fracture properties under high-speed impact. High-speed and high-resolution sequential images are required to study the interaction of the bullet with the brittle ceramic materials. In this study, a device is developed to capture the sequence of high-speed impact/penetration phenomena. This system consists of a speed measurement device, a microprocessor-based camera controller, and multiple CCD cameras. By using a linear array sensor, the speed-measuring device can measure a small (diameter: up to 1 2 mm) and fast (speed: up to Mach 3) bullet. Once a bullet is launched, it passes through the speed measurement device where its time and speed is recorded, and then, the camera controller computes the exact time of arrival to the target during flight. Then, it sends the trigger signal to the cameras and flashes with a specific delay to capture the impact images sequentially. It is almost impossible to capture high-speed images without the estimation of the time of arrival. We were able to capture high-speed images using the new system with precise accuracy.

• Journal of Advanced Navigation Technology
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• v.26 no.2
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• pp.72-77
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• 2022

Among the techniques of reinforcement learning, Q-Learning means learning optimal policies by learning Q functions that perform actionsin a given state and predict future efficient expectations. Q-Learning is widely used as a basic algorithm for reinforcement learning. In this paper, we studied the effectiveness of selecting and learning efficient paths by designing policies and rewards based on Q-Learning. In addition, the results of the existing algorithm and punishment compensation policy and the proposed punishment reinforcement policy were compared by applying the same number of times of learning to the 8x8 grid environment of the Frozen Lake game. Through this comparison, it was analyzed that the Q-Learning punishment reinforcement policy proposed in this paper can significantly increase the learning speed compared to the application of conventional algorithms.