• Journal of the Korean Academy of Esthetic Dentistry
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• v.27 no.2
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• pp.66-74
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• 2018

Composite resin restoration on class II cavities is a challenging procedure since it is tough to replicate proper contact, the natural shape of the tooth, etc. Moreover, it is not familiar with the procedure and tools for this specific situation, neither. Nowadays the patients, however, request more and more composite restorations which are relatively quick and more esthetic. In this case report, the class II composite resin restoration procedure is illustrated step by step. Every step must be considered its final consequence thoroughly. In this approach, we can minimize the finishing procedure and save our effort and time.

• Journal of the Korean Chemical Society
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• v.66 no.4
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• pp.323-332
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• 2022

The purpose of this study is to investigate the effects of science classes using smart devices that combine augmented reality (AR) and virtual reality (VR) on the scientific attitude of middle school gifted students. In addition, it is intended to find out the perception of science classes using these smart devices. In addition to actual experiments, a science class program that allows students to experience science experiments virtually using AR and VR was applied to 15 middle school gifted students. Before and after the application of the program, the questionnaire is to investigate the interest in scientific classes, the attitude toward science exploration, and the professional interest in science, and the recognition of classes that combine AR and VR. In addition, through in-depth interviews, the perceptions of gifted students was accurately investigated. As a result of this study, the content of science classes and instructors showed high class satisfaction, but the smart devices and applications used during the science classes showed lower class satisfaction than others. As a result of comparing and analyzing the pre-post of gifted students, interest in science class, attitude toward science inquiry, and professional interest in science increased significantly among the sub-areas of the scientific attitude test. As a result of analyzing free responses and indepth interviews, gifted students responded with the advantage that classes using smart devices that combine AR and VR can be tested quickly and safely for a short time compared to actual experiments. On the other hand, they responded with low completeness of the application and dizziness when operating virtual reality. Based on this, implications for the development of applications and instructional programs using advanced technologies that can experience realistically limited scientific experiments such as experimental preparation, class time, and risk factors were obtained.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2853-2873
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• 2013

Over the last few years, one of the most common purposes of smart homes is to provide human centric services in the domain of u-healthcare by analyzing inhabitants' daily living. Currently, the major challenges in activity recognition include the reliability of prediction of each classifier as they differ according to smart homes characteristics. Smart homes indicate variation in terms of performed activities, deployed sensors, environment settings, and inhabitants' characteristics. It is not possible that one classifier always performs better than all the other classifiers for every possible situation. This observation has motivated towards combining multiple classifiers to take advantage of their complementary performance for high accuracy. Therefore, in this paper, a method for activity recognition is proposed by optimizing the output of multiple classifiers with Genetic Algorithm (GA). Our proposed method combines the measurement level output of different classifiers for each activity class to make up the ensemble. For the evaluation of the proposed method, experiments are performed on three real datasets from CASAS smart home. The results show that our method systematically outperforms single classifier and traditional multiclass models. The significant improvement is achieved from 0.82 to 0.90 in the F-measures of recognized activities as compare to existing methods.

• Journal of the Korea Convergence Society
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• v.12 no.5
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• pp.147-155
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• 2021

This study covers the effectiveness of SNS utilization education for the elderly. Participants in the study conducted in-depth interviews with trainees currently participating in education and mentors of the same age who are working as assistive instructors. The study deals with whether SNS utilization education, which is considered difficult, can be a more valid class when an elderly person of the same age becomes a mentor and teaches a class. The results of the study said that it was a fun and rewarding education after using SNS for the elderly, free from fear of difficult devices due to the friendly consideration and empathy of the same age. If a mentor of the same age is used for education on SNS for the elderly, SNS education, which has been considered difficult and burdensome for the elderly, is expected to be activated with more flexible education.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.41-45
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• 2019

In this paper, we propose the interference cancellation scheme of end-to-end method algorithm for power line communication (PLC) systems in smart grid. The proposed scheme estimates the channel noise information of receiver by applying a deep learning model at the receiver. Then, the estimated channel noise is updated in database. In the modulator, the channel noise which reduces the power line communication performance is effectively removed through interference cancellation technique. As an impulsive noise model, Middleton Class A interference model was employed. The performance is evaluated in terms of bit error rate (BER). From the simulation results, it is confirmed that the proposed scheme has better BER performance compared to the theoretical model based on additive white Gaussian noise. As a result, the proposed interference cancellation with deep learning improves the signal quality of PLC systems by effectively removing the channel noise. The results of the paper can be applied to PLC for smart grid and general communication systems.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.1147-1158
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• 2020

The purpose of this study was to measure the engine torque and rotational speed of a 67 kW class agricultural tractor according to tire type during plow tillage and to analyze the gear strength of the driving shift for the tractor. A field test was performed under the condition with a single tire (Test A) and dual tires (Test B) to increase the ground width of the rear tires. A load monitoring system was developed, and the engine torque and rotational speed were measured using controller area network (CAN) communication. The engine torque and rotational speed during plow tillage were calculated as the equivalent torque and speed using Palmgren Miner's rule. As a result, the equivalent torque and speed in Test A and Test B were 181.0 Nm and 1,913 rpm and 206.1 Nm and 2,130 rpm, respectively. As the ground width of the rear tire was increased, the bending stress in Test B was about 9.9 to 10.5% higher than that of the Test A, and the contact stress was about 4.6 to 4.9% higher than that of the Test A. Under all conditions, the safety factor for the bending and contact stress was 1 or more. Thus, the driving shift gears for the dual tire type are considered safe.

• Journal of Drive and Control
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• v.19 no.1
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• pp.16-25
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• 2022

The purpose of this study was to calculate and analyze the engine load factor of major agricultural operations using a 78 kW class agricultural tractor for estimating the emission of air pollutants and greenhouse. Engine load data were collected using controller area network (CAN) communication. Main agricultural operations were selected as plow tillage (PT), rotary tillage (RT), baler operation (BO), loader operation (LO), driving on soil (DS), and driving on concrete (DC). The engine power was calculated using the measured engine load data. A weight factor was applied to load factor for considering usage ratio according to agricultural operations. Weight factors for different agricultural operations were calculated to be 27.4%, 32.9%, 17.5%, 7.7%, 4.5%, and 10.0% for PT, RT, BO, LO, DS, and DC, respectively. As a result of the field test, load factors were 0.74, 0.93, 0.41, 0.23, 0.27, and 0.21 for PT, RT, BO, LO, DS, and DC, respectively. The engine load factor was the highest for RT. Finally, as a result of applying the weight factor for usage ratio of agricultural operations, the integrated engine load factor was estimated to be 0.63, which was about 1.31 times higher than the conventional applied load factor of 0.48. In future studies, we plan to analyze the engine load factor by considering various horsepower and working conditions of the tractor.

• Journal of Digital Convergence
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• v.10 no.3
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• pp.1-12
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• 2012

According to recent trends of ubiquitous learning with the advent of smart devices, this study was to suggest for the successful achievement of "Smart Campus" initiatives by experiencing an instruction with smart-pads (tablet PCs) in a university. A pilot project was conducted as a part of building a Smart Campus in S university in Gyeong-gi Province in Korea for the study. The class was held in the Summer semester in 2011 with six participants. Using research methodologies such as semi-structured interviews and stimulated recall, perceived academic performances, satisfaction, and the usability of smart-pads were analysed. Main results included high perceived academic performances, satisfaction, and the usability, however, some negative responses also detected on the variables. Based on the results, it was suggested that specific instructional strategies should be developed in terms of hardware, software and humanware.

• Journal of Digital Convergence
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• v.15 no.4
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• pp.65-71
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• 2017

With advances in technology, many researchers have made an effort to find out educational methods with customized instruction. The purpose of the research is to investigate i) if flipped learning is beneficial for the students taking intermediate-level English grammar and writing class compared with the traditional class, ii) if the flipped learning class is advantageous for all the score level students in terms of student achievement and iii) if the students feel motivated with the flipped learning class. T-test was utilized to determine any differences between pretest and posttest in student achievement. The result in terms of the academic achievement revealed that the flipped classroom approach for the low score group was found to be the least effective among others. In the case of flipped learning teaching method, the instructor should develop contents according to the level of learners. The development of customized contents tailored to the level of learners will enhance learners' learning achievement.

• Journal of Korean Elementary Science Education
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• v.35 no.2
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• pp.166-180
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• 2016

This paper examines the effects on academic achievement, scientific process skills and affective domain for elementary students learning the 'Chicken life cycle' through traditional science class versus a smart media based STEAM approach. Students designed and built a hatching jar and created a smart media content for chickens using time-lapse technology. This STEAM program was developed to improve their scientific concepts of animals over nine periods of classes using integrated education methods. The experimental study took place in the third grade of public schools in a province, with the STEAM approach applied in 2 classes (44 students) and the traditional discipline approach implemented in 2 classes (46 students). The STEAM education significantly influenced the improvement of academic achievements, basic scientific process skills and affective domain. The results suggest that this STEAM approach for teaching scientific concepts of animal life cycles has the performance in terms of knowledge, skills and affect gain achievements in elementary school students' learning when compared to a traditional approach. Moreover, the smart media based STEAM program is helpful to lead students to engage in integrated problem-solving designs and learning science and technology.