• Education of Primary School Mathematics
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• v.20 no.1
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• pp.37-52
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• 2017

The purpose of this thesis is to analyze the current status of a program for an elementary math class for gifted students in Daegu and to propose a remedy. The main results of this thesis are as follows. First, goals of the gifted class and the basic operation direction were satisfactory, however plans for parent training programs and self evaluation of the classes were not presented. Therefore, it needs when and how to do for specific plan of gifted class evaluation and parent training programs. Second, The annual instruction plan has been restricted to the subject matter education and field trips and has not included specific teaching methods in accordance with the contents of learning program. The management of gifted classes, therefore, requires not only the subject matter education and field trips but also output presentations, leadership programs, voluntary activities, events and camps which promote the integral development of gifted students. Third, there is no duplication of content to another grade, and various activities did not cover the whole scope of math topics(eg. number and operation, geometry, measurement, pattern) equally. In accordance with elementary mathematics characteristics, teachers should equally distribute time in whole range of mathematics while they teach students in the class because it is critical to discover gifted students throughout the whole curriculum of elementary mathematics. Fourth, as there are insufficient support and operational lack of material development, several types of programs are not utilized and balanced. It is necessary for teachers to try to find the type of teaching methods in accordance with the circumstances and content, so that students can experience several types of programs. If through this study, we can improve the development, management and quality of gifted math programs, it would further the development of gifted education.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.3
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• pp.329-343
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• 1995

Traditionally, machining process sequence was influenced and constrained by the design information obtained from CAD data base, i.e., class of operations, geometric shape, tooling, geometric tolerance, etc. However, even though all the constraints from design information are considered, there may exist more than one way to feasibly machine parts. This research is focused on the integrated problem of operations sequencing and machine tools selection in the presence of the product mix and their production volumes. With the transitional costs among machining operations, the operation sequencing problem can be formulated as a well-known Traveling Salesman Problem (TSP). The transitional cost between two operations is expressed as the sum of total machining time of the parts on a machine for the first operation and transportation time of the parts from the first machine to a machine for the second operation. Therefore, the operation sequencing problem formulated as TSP cannot be solved without transitional costs for all operation pairs. When solved separately or serially, their mutual optima cannot be guaranteed. Machining operations sequencing and machine tool selection problems are two core problems in process planning for discretely machined parts. In this paper, the interrelated two problems are integrated and analyzed, zero-one integer programming model for the integrated problem is formulated, and the solution methods are developed using a Tabu Search technique.

• Communications of the Korean Mathematical Society
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• v.27 no.4
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• pp.689-699
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• 2012

(S, *) is a semigroup S equipped with a unary operation "*". This work is devoted to a class of unary semigroups, namely E-$inversive$ *-$semigroups$. A unary semigroup (S, *) is called an E-inversive *-semigroup if the following identities hold: $$x^*xx^*=x^*$$, $$(x^*)^*=xx^*x$$, $$(xy)^*=y^*x^*$$. In this paper, E-inversive *-semigroups are characterized by several methods. Furthermore, congruences on these semigroups are also studied.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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• pp.525-538
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• 2016

This study is to investigate the effect of the amusement factor and the motive of participation in skin-scuba class on the satisfaction with university life with the university students participating in the skin-scuba class and to provide the practical research data for the development of the marine sports, for the proper operation of skin-scuba class, and for the leisure life which the university students may lack. For these purposes, technical statistics between questions were disposed in order to grasp the average and standard deviation on each variables, exploratory factor analysis and reliability analysis were conducted for the reliability and validity of the scale, and correlation analysis and multiple regression analysis were conducted to test the casuality of amusement factor, the motive of participation in skin-scuba class and the satisfaction with university life as the research methods. Research results showed that it was confirmed that the amusement factor and the motive of participation in skin-scuba class act as the important variables in the satisfaction with university life and it was predicted that the motive of participation in skin-scuba class and the amusement factor had interrelation with parameter. Therefore, a variety of programs reflecting the amusement factors should motivate the university students to particiapte in the skin-scuba class to increase the satisfaction with university life and to encourage the re-participation of students.

• The Journal of the Korea Contents Association
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• v.21 no.8
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• pp.271-284
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• 2021

The purpose of this study is to explore the current status and effects of online discussion classes in universities. To this end, a survey was conducted on university students attending a total of four universities in Seoul and Gyeonggi Province to diagnose their perceptions of the operation of online discussion classes and their effects. The collected data were analyzed using frequency analysis, descriptive statistical analysis, cross-analysis, F-test, T-test, and Scheffe test by applying SPSS program. As a result of the study, first, it was found that 'non-real-time recorded lessons' and 'real-time interactive video lessons' were mainly conducted at universities after the COVID19 crisis. Second, in the online class method, 'real-time interactive video class' had a positive effect on 'debate class preference' and was found to be more meaningful. Third, college students recognized participation in online discussion classes as a foundation for expanding creative thinking skills, suggesting that strengthening through smooth communication and exchanges based on learners' sufficient cognitive processes on discussion methods and procedures is more helpful.

• Journal of Korean society of Dental Hygiene
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• v.18 no.4
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• pp.525-533
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• 2018

Objectives: This retrospective study evaluated the changes in the airway width after the orthognathic surgery associated with the skeletal Class III malocclusion. Methods: The lateral cephalograms of 30 adult patients were taken before and immediately after the operation, and after the orthodontic treatment. The angles and distances of them were measured and compared. Results: Before the surgery, the mean value of mandibular (S-B) setback was 9.66 mm, and moved by 1.56 mm anteriorly after the orthodontic treatment. The ANB increased by 5.42 degrees, since then it decreased by 0.68 degree. The hyoid bone (S-APH) moved by 5.05 mm posteriorly, but then moved by 2.26 mm anteriorly. The soft tissue width of laryngeal pharynx (apw2-ppw2) was narrowed by 1.04 mm, and decreased by additional 0.83 mm after the orthodontic treatment. Conclusions: As the mandible was moved back, the location of hyoid bone and laryngeal pharynx were moved backward.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.3
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• pp.376-384
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• 2018

Selection of suitable ice class for ships operation is an important but not simple task. The increased exploitation of the Polar waters, both seasonal periods and geographical areas, as well as the introduction of new international design standards such as Polar Code, reduces the relevancy of using existing experience as basis for the selection, and new methods and knowledge have to be developed. This paper will analyse what can be the limiting ice thickness for ships navigating in the Russian Arctic and designed according to the Finnish-Swedish ice class rules. The permanent deformations of ice-strengthened shell structures for various ice classes is determined using MT Uikku as the typical size of a vessel navigating in ice. The ice load in various conditions is determined using the ARCDEV data from the winter 1998 as the basic database. By comparing the measured load in various ice conditions with the serviceability limit state of the structures, the limiting ice thickness for various ice classes is determined. The database for maximum loads includes 3-weeks ice load measurements during April 1998 on the Kara Sea mainly by icebreaker assistance. Gumbel 1 distribution is fitted on the measured 20 min maximum values and the data is divided into various classes using ship speed, ice thickness and ice concentration as the main parameters. Results encouragingly show that present designs are safer than assumed in the Polar Code suggesting that assisted operation in Arctic conditions is feasible in rougher conditions than indicated in the Polar Code.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.2
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• pp.45-53
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• 2024

The maintenance of semiconductor equipment is crucial for the continuous growth of the semiconductor market. System management is imperative given the anticipated increase in the capacity and complexity of industrial equipment. Ensuring optimal operation of manufacturing processes is essential to maintaining a steady supply of numerous parts. Particularly, monitoring the status of substrate transfer robots, which play a central role in these processes, is crucial. Diagnosing failures of their major components is vital for preventive maintenance. Fault diagnosis methods can be broadly categorized into physics-based and data-driven approaches. This study focuses on data-driven fault diagnosis methods due to the limitations of physics-based approaches. We propose a methodology for data acquisition and preprocessing for robot fault diagnosis. Data is gathered from vibration sensors, and the data preprocessing method is applied to the vibration signals. Subsequently, the dataset is trained using Gradient Tree-based XGBoost machine learning classification algorithms. The effectiveness of the proposed model is validated through performance evaluation metrics, including accuracy, F1 score, and confusion matrix. The XGBoost classifiers achieve an accuracy of approximately 92.76% and an equivalent F1 score. ROC curves indicate exceptional performance in class discrimination, with 100% discrimination for the normal class and 98% discrimination for abnormal classes.

• Knowledge Management Research
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• v.21 no.2
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• pp.119-135
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• 2020

Owing to pandemic (COVID-19), the traditional face-to-face education method has been changed to the non-face-to-face real-time online education methods. Using a real time-based video conference system, synchronous education can be adopted by face-to-face class easily. Specially, it is very important to minimize the difference in learning effects between face-to-face and non-face-to-face in Entrepreneurship education. In this study, in order to derive the factors that affect the satisfaction of learners in synchronous online education, authors collected data from learners taking a synchronous entrepreneurship course. Through previous research, learned the reality of education and the composition of lessons. Spatiotemporal effectiveness, mentor ability, and educational environment influence learning satisfaction. PLS-SEM results revealed that it was confirmed that only spatiotemporal effects affect learner satisfaction. However, the education environment (fluent operation and convenience of function use of real-time based online conference system) effect teaching presence, class structure, and spatiotemporal effects. Through this research, we hope to provide theoretical and practical support for developing effective teacher activities, proper lesson structure, convenient function of the conference system, and learner-centered online learning environment when developing synchronous online classes.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.110-117
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• 2021

The purpose of the study is to develop effective teaching methods to strengthen the major learning capabilities of electronic engineering learners through inquiry learning using computing thinking ability. To this end, first, in the electronic engineering curriculum, we performed teaching-learning through an inquiry and learning model related to mathematics, probability, and statistics under the theme of various majors in electronic engineering, focusing on understanding computing thinking skills. Second, an efficient electronic engineering subject inquiry class operation using computing thinking ability was conducted, and electronic engineering-linked education contents based on the components of computer thinking were presented. Third, by conducting a case study on inquiry-style teaching using computing thinking skills in the electronic engineering curriculum, we identified the validity of the teaching method to strengthen major competency. In order to prepare for the 4th Industrial Revolution, by implementing mathematics, probability, statistics-related linkage, and convergence education to foster convergent talent, we tried to present effective electronic engineering major competency enhancement measures and cope with innovative technological changes.