• Korean Journal of Child Studies
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• v.25 no.3
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• pp.1-14
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• 2004

This study focused on the development and application of learning cycle model for promoting children's creativity and problem solving ability. The learning cycle approach consists of four phases : awareness, exploration, investigation, and concept application. The program consists of 20 scientific activities. A total of 70 children participated the 10 week program to examine the effectiveness of this model. The experimental design included a pretest, treatment, and posttest. Results showed that the experimental group children scored significantly higher on the creativity and problem solving tests in the posttest than the control group children.

• International journal of advanced smart convergence
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• v.7 no.4
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• pp.19-26
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• 2018

One of the distinct features of Wireless Sensor Networks (WSNs) is duty cycling mechanism, which is used to conserve energy and extend the network lifetime. Large duty cycle interval introduces lower energy consumption, meanwhile longer end-to-end (E2E) delay. In this paper, we introduce an energy consumption minimization problem for duty-cycled WSNs. We have applied Q-learning algorithm to obtain the maximum duty cycle interval which supports various delay requirements and given Delay Success ratio (DSR) i.e. the required probability of packets arriving at the sink before given delay bound. Our approach only requires sink to compute Q-leaning which makes it practical to implement. Nodes in the different group have the different duty cycle interval in our proposed method and nodes don't need to know the information of the neighboring node. Performance metrics show that our proposed scheme outperforms existing algorithms in terms of energy efficiency while assuring the required delay bound and DSR.

• Journal of The Korean Association For Science Education
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• v.29 no.4
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• pp.450-462
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• 2009

In this study, we investigated the influences of teaching practices upon pre-service secondary teachers' perceptions on the learning cycle by their understanding of it. Surveys on their understanding and perceptions of the learning cycle were administered to 37 seniors at the department of chemistry education in two colleges of education before teaching practices, and the survey for perceptions of the learning cycle was given to them after teaching practices. In addition, we selected seven pre-service teachers with decreased perceptions after teaching practices, and interviewed them thoroughly to investigate the factors influencing the decrease of their perceptions. The results revealed that the degree of pre-service secondary teachers' understanding of the learning cycle was not high, but their perceptions on the advantage/disadvantage of the learning cycle, their willingness to implement it, and the external aids influencing implementation were relatively positive before they practiced teaching. However, their positive perceptions more or less decreased after entering the teaching practice and the degree of decrease for those having a higher understanding of the learning cycle was larger than those having a lower understanding of it. The results of the interviews suggested the factors of pre-service teachers, students, curriculum and outside conditions as the causes of the decrease. Educational implications of these findings are discussed.

• Journal of The Korean Association For Science Education
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• v.11 no.1
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• pp.15-24
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• 1991

The purpose of this study was to investigate the effectiveness of Learning Cycle approach to change the concept of density. The results of the study were as follows : 1) Students already had various types of preconception related to density before formal learning. These preconceptions mostly differ from scientific concepts. 2) Male students were much better than female ones in the development of scientific concepts before formal learning. These differences were found statistically significant(P<0.01). 3) The higher the cognitive level of the students, the better the development of scientific concepts. 4) In the change of preconceptions to scientific concepts by treatment, there was significant difference between control group and experimental group at the 0.05 level. It was found that Learning Cycle approaches were more effective than traditional approaches in acquiring the concept of density. 5) It was found that there was no significant difference On the retention level of the concept of density between control group and experimental group.

• Smart Structures and Systems
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• v.30 no.6
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• pp.571-582
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• 2022

Optimal life-cycle management is a challenging issue for deteriorating regional bridges. Due to the complexity of regional bridge structural conditions and a large number of inspection and maintenance actions, decision-makers generally choose traditional passive management strategies. They are less efficiency and cost-effectiveness. This paper suggests a deep reinforcement learning framework employing double-deep Q-networks (DDQNs) to improve the life-cycle management of deteriorating regional bridges to tackle these problems. It could produce optimal maintenance plans considering restrictions to maximize maintenance cost-effectiveness to the greatest extent possible. DDQNs method could handle the problem of the overestimation of Q-values in the Nature DQNs. This study also identifies regional bridge deterioration characteristics and the consequence of scheduled maintenance from years of inspection data. To validate the proposed method, a case study containing hundreds of bridges is used to develop optimal life-cycle management strategies. The optimization solutions recommend fewer replacement actions and prefer preventative repair actions when bridges are damaged or are expected to be damaged. By employing the optimal life-cycle regional maintenance strategies, the conditions of bridges can be controlled to a good level. Compared to the nature DQNs, DDQNs offer an optimized scheme containing fewer low-condition bridges and a more costeffective life-cycle management plan.

• Journal of Korean Elementary Science Education
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• v.21 no.1
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• pp.135-142
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• 2002

This paper aims to compare the effects of two teaching methods, the discovery-observational(DO) and the expository-observational(EO) instructions, on students learning interest in the life cycle of fruit fly. The subjects, 463 third-graders from two elementary schools in Changwon City, were divided into two groups, the DO group and the EO group. After the instruction on the life of the flies in two different teaching ways, a questionnaire with 13 items was devised regarding the students' interest, and the subjects were asked to respond to it. The results reveal that the general mean score of the DO group is higher than that of the EO group. Also, the DO group obtains the higher mean score in each item, except two items about knowledge learning. The differences of the mean scores of the two types, general as well as item-individual, between the two groups are statistically significant. This suggests that the class about the life cycle of living creatures easily getatable and observable, such as fruit flies, should be student-centered investigatory one, where students themselves collect them and observe the process of their growth and whole cycle.

• Journal of The Korean Association For Science Education
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• v.28 no.5
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• pp.409-423
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• 2008

Many researches have reported that it is difficult to solve students' difficulties in learning science with teaching models focused on certain aspects because of various reasons. Recently, in science education research, the integrated perceptive has been to put emphasis on understanding complex situations of real teaching and learning. In this research context, the integrated mental model theory that were considered as a whole factor related to learning has been studied by integrating previous studies that related to students' conceptions and learning in various fields. Thus, it is needed that the teaching model be based on the integrated mental model theory to help students to solve their difficulties. The purpose of this research was to develop a new teaching model based on the integrated mental model theory to address this issue. We reviewed current studies on student difficulties and teaching models. After this, we developed 4M learning cycle teaching model. In this paper, we described the process of developing a new teaching model and discussed how to apply this teaching model to the practices. We also discussed the effects of 4M learning cycle teaching model based on the integrated mental model theory in learning science with its implications.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.2
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• pp.49-66
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• 2014

This paper studies optimal consumption and investment behaviors of an individual when risky asset returns and her income are affected by the business cycle. The investor considers the incomplete information risk of unobservable macroeconomic conditions and updates her belief of expected risky asset returns through Bayesian learning. We find that the optimal investment strategy, certainty equivalent wealth, and portfolio hedging demand significantly depend on the belief about the macroeconomic conditions.

• Journal of the Korea Society of Computer and Information
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• v.22 no.3
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• pp.69-79
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• 2017

In this paper, we propose our four-phase life cycle of P2P botnet with corresponding detection methods and the future direction for more effective P2P botnet detection. Our proposals are based on the intensive analysis that compares existing P2P botnet detection schemes in different points of view such as life cycle of P2P botnet, machine learning methods for data mining based detection, composition of data sets, and performance matrix. Our proposed life cycle model composed of linear sequence stages suggests to utilize features in the vulnerable phase rather than the entire life cycle. In addition, we suggest the hybrid detection scheme with data mining based method and our proposed life cycle, and present the improved composition of experimental data sets through analysing the limitations of previous works.

• Journal of The Korean Association For Science Education
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• v.16 no.1
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• pp.13-34
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• 1996

The purpose of this study is to develop appropriate science teaching models which can be applied effectively to relevant situations. Five science teaching models; cognitive conflict teaching models, generative teaching model, learning cycle teaching model, hypothesis verification teaching model and discovery teaching model, were identified from the existing models. The teaching models were modified and in primary and secondary students using a nonequivalent pretest-posttest control group design. Major findings of this study were as follows: 1. For teaching science concepts, three teaching models were found more effective; cognitive conflict teaching model, generative teaching model and discovery teaching model. 2. For teaching inquiry skills, two teaching models were found more effective; learning cycle teaching model and hypothesis verification teaching model. 3. For teaching scientific attitudes, two teaching models were found more effective; learning cycle teaching models and discovery teaching model. Each teaching model requires specific learning environment. It is strongly suggested that teachers should select a suitable teaching model carefully after evaluating the learning environment including teacher and student variables, learning objectives and curricular materials.