• Geomechanics and Engineering
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• v.24 no.3
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• pp.237-251
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• 2021

The main purpose of this study is to investigate the performance of the proposed hybrid teaching-learning based optimization algorithm on the optimum design of reinforced concrete (RC) cantilever retaining walls. For this purpose, three different design examples are optimized with 100 independent runs considering continuous and discrete variables. In order to determine the algorithm performance, the optimization results were compared with the outcomes of the nine powerful meta-heuristic algorithms applied to this problem, previously: the big bang-big crunch (BB-BC), the biogeography based optimization (BBO), the flower pollination (FPA), the grey wolf optimization (GWO), the harmony search (HS), the particle swarm optimization (PSO), the teaching-learning based optimization (TLBO), the jaya (JA), and Rao-3 algorithms. Moreover, Rao-1 and Rao-2 algorithms are applied to this design problem for the first time. The objective function is defined as minimizing the total material and labor costs including concrete, steel, and formwork per unit length of the cantilever retaining walls subjected to the requirements of the American Concrete Institute (ACI 318-05). Furthermore, the effects of peak ground acceleration value on minimum total cost is investigated using various stem height, surcharge loads, and backfill slope angle. Finally, the most robust results were obtained by HTLBO with 50 populations. Consequently the optimization results show that, depending on the increase in PGA value, the optimum cost of RC cantilever retaining walls increases smoothly with the stem height but increases rapidly with the surcharge loads and backfill slope angle.

• Journal of the Korean School Mathematics Society
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• v.2 no.1
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• pp.93-104
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• 1999

The subject of this study was the graph of relation of direct inverse proportion, linear function and quadratic function in the 1st, 2nd and 3rd grade of current middle school mathematics curriculum. GSP materials were developed to simplify the principle, trait and characteristics of graphs and make them easier to understand. The overall aim of the materials is to improve the effectiveness of teaching and learning through the utilization of enhanced students' practice. Additionally, the use of the GSP will be useful in the development of mere effective materials. The effectiveness of the GSP materials will be as followings. 1. The step by step approach of GSP materials through computer interaction will enhance students motivation and interest in mathematics. 2. By presenting the subject matter simply and in a variety of ways, difficult concepts can be understood without the use of complex mathematical calculation. 3. The GSP program is different from CAI and other software programs. It should be used only after learning how to input and output data.

• Journal of the Korean School Mathematics Society
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• v.3 no.2
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• pp.123-131
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• 2000

In order to educate future leaders of the new age, we should help students to increase their basic knowledge, thinking and problem solving ability. It is necessary that we should use multi-media, computer as well as old teaching-learning material to improve students' basic knowledge and to motivate their interest in mathematics in the small-sized Middle School situated on the agricultural and fishery village. In solving this problem, it is ultimately necessary that we should utilize CAI program on the learning achievement in mathematics for the students to understand basic concept, principle, law and to promote teaching-learning process considered on individual different abilities. Therefore, this study is on the effect of students' interest and learning achievement in mathematics when we develop CAI program focusing on the lesson statistics in the 3rd Grade Middle School Mathematics Textbook and explain the concept and principle of statistics through using exact and various techniques of computers

• School Mathematics
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• v.12 no.4
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• pp.619-638
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• 2010

In this paper, we listed and reviewed some properties on polygonal numbers, pyramidal numbers and Pascal's triangle, and Fibonacci sequence. We discussed that the properties of gnomonic numbers, polygonal numbers and pyramidal numbers are explained integratively by introducing the generalized k-dimensional pyramidal numbers. And we also discussed that the properties of those numbers and relationships among generalized k-dimensional pyramidal numbers, Pascal's triangle and Fibonacci sequence are suitable for teaching and learning of mathematical reasoning and connections.

• Research in Mathematical Education
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• v.21 no.1
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• pp.35-46
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• 2018

In this perspective paper, we present seven elements of the appropriate educator mindset for teaching in the constructivist elementary mathematics classroom. The elements include supporting students as they construct their own understanding, eliminating deficit view of slow learners, setting new understanding and growth as the learning objective, providing opportunities to co-construct meaning with peers, using student contributions as the source of curricular material, encouraging all students to participate in learning, and providing instruction not bounded by time. In our struggles to provide authentic, inclusive elementary classrooms, we hope that our discussion of the educator mindset can increase discourse on constructivism from philosophy to practice in the community of mathematics education and policy makers.

• English Language & Literature Teaching
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• v.15 no.2
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• pp.121-150
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• 2009

This paper deals with contrastive analysis and interlanguage with respect to adjective ordering. It aimed to investigate how similar and different the orders of descriptive adjectives are in English and Korean, and how Korean EFL learners perceive the sequences of English descriptive adjectives. Data were collected from native English speakers and native Korean speakers and Korean EFL learners. The contrastive analysis showed that the order of English adjectives was size, opinion, condition, age, color, shape, material, and origin, whereas the Korean order was condition, age, opinion, color, size, shape, material, and origin. The relative order of the interlanguage was shown to be age, size, opinion, shape, condition, color, origin, and material, with the exceptions of the order of condition preceding age and that of size being the same position as condition. The interlanguage data manifested different aspects of ordering when compared with English and Korean: Some adjective combinations were similar to both English and Korean; Some were different from English or Korean; Some were different from both English and Korean. These ordering patterns are discussed in terms of such principles as the nouniness principle, the subjectivity/objectivity principle, the iconic principle, etc. On the basis of these results, some helpful suggestions are made.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.945-953
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• 2006

The researchers in the field of cognitive science and learning science suggest that the teaching activity induces the elaborative and meaningful learning. Actually, lots of research findings have shown the beneficial effect of learning by teaching such as peer tutoring. But peer tutoring has some limitations in the practical learning context. To overcome some limitations, the new concept of "learning by teaching" through the agent called Teachable Agent. The teachable agent is a modified version of traditional intelligent tutoring system that assigns a role of tutor to teach the agent. The teachable agent monitors individual difference and provides a student with a chance for deep learning and motivation to learn by allowing them to play an active role in the process of learning. That is, The teaching activity induces the elaborative and meaningful learning. This study compared the effects of our teachable agent, KORI, and peer tutoring on the cognition and motivation. The field experiment was conducted to examine whether learning by teaching the teachable agent would be more effective than peer tutoring and reading condition. In the experiment, all participants took 30 minutes lesson on rock and rock cycle together to acquire the base knowledge in the domain. After the lesson, participants were randomly assigned to one of the three experimental conditions; reading condition, peer tutoring condition, and teachable agent condition. Next, participants of each condition moved into separated place and performed their own learning activity. After finishing all of the learning activities in each condition, all participants were instructed to rate the interestingness using a 5-point scale on their own learning activity and leaning material, and were given the comprehension test. The results indicated that the teachable agent condition and the peer tutoring condition showed more interests in the learning than the reading condition. It is suggested that teachable agent has more advantages in overcoming the several practical limitations of peer tutoring such as restrictions in time and place, tutor's cognitive burden, unnecessary interaction during peer tutoring. The applicability and prospects of the teachable agent as an efficient substitute for peer tutoring and traditional intelligent tutoring system were also discussed.

• Journal of Science Education
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• v.39 no.1
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• pp.1-14
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• 2015

This study aims to find out the effect of pre-service elementary teachers' experiences of inquiry performance in the life on their images about a scientist and science teaching anxiety. Thus, this study selected 162 college juniors who completed 'Science Teaching Material Research & Teaching Methods' for one semester at a university of education. Groups of 3 to 4 pre-service teachers were made to select one of the 10 experimental topics and inquired it for themselves, and make a presentation about the results before the other pre-service teachers. The results of this study can be summarized as below. Firstly, as a result of investigating pre-service elementary teachers' opinions about the characteristics of scientists, it was found that they thought of scientists prudent, intellectually superior, creative, and hard-working, but did not consider them artistic or religious, no matter if they had inquiry performance experiences. Especially, to such characteristics as intellectually-superior, creative, open-minded, outgoing and responsible, they showed more positive responses after inquiry performances. Besides, in scientists' activity types shown in pre-service elementary teachers' drawing pictures of a scientist, 'Experimental Activity' increased most after their inquiry performances, and in the place of activity, 'Laboratory' was most since it was related to activity types. Secondly, as a result of examining per-service elementary teachers' science teaching anxiety before and after inquiry performances, it was found that they showed statistically significant differences in all the domains, scientific knowledge, inquiry class preparation and inquiry class management. This finding could be interpreted as their inquiry experiences had positive effect on their having confidence in teaching science.

• Journal of Science Education
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• v.34 no.1
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• pp.84-92
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• 2010

We analyzed learning materials from web sites of the Ministry of Environments, the Ministry of Land, Transport and Maritime Affairs and Korea Energy Management Corporation to help people to develop and utilize web-based multimedia teaching materials. The contents of web-based multimedia teaching materials for environmental educations were generally concentrated in 304 cases of natural environments (22.1%), 250 cases of environmental contaminations (16.5%) and 187 cases of environmental preservation plans (12.4%). It did not significantly deviate from traditional teaching-learning contents being conducted focusing on environmental pollutions of the past. The types of web-based multimedia teaching materials for environmental educations were 934 cases of teaching plans (61.8%), 156 cases of documentaries (10.3%) and 128 cases of e-text information (8.5%). The web-based multimedia teaching materials by school-levels showed that there were 796 for primary schools (35.3%), 588 for middle schools (26.1%) and 320 for high schools (14.2%). It also showed that environmental education with similar contents were provided even in advanced schools. Therefore, it is believed that there needs development of various types of teaching materials while the fields of environmental education contents are covered with connectivity according to school-levels.

• Journal of The Korean Association For Science Education
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• v.33 no.6
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• pp.1139-1153
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• 2013

Misconceptions are one of the most important and long-lasting studied themes on science education. It is because their nature is obstinate and settled as well as they corrupt students' understanding of science concepts. This study examines whether preservice elementary school teachers enrolled in biology teaching material research course changed positively on science teaching efficacy and correcting life science misconceptions when they used the handbook developed for this study. The handbook comprises 203 life science concepts surveyed among preservice teachers holding from advanced researches and arranged by 2007 Revised Science Curriculum. 107 preservice elementary school teachers participated in the study. Forty-six (46) of them were assigned to the experimental group and the other 61 to the control group. ANOVA was conducted for analyzing data. Science Teaching Efficacy Belief Instrument (STEBI) and the life science misconception test which was developed for this study, were administrated as assessing instruments for pretest and posttest. The experimental group, using the handbook, acquired higher scores in both tests on statistical significance level than the control group who were not using the handbook. The results indicate the handbook developed for correcting life science misconceptions for this study is effective in enhancing science teaching efficacy and correcting life science misconceptions.