• Journal of the Korean Society of Systems Engineering
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• v.17 no.2
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• pp.129-138
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• 2021

Today, as the number of vehicles equipped with autonomous driving functions increases, the use of various sensors increases, and the complexity of system configuration increases. The ISO 26262 standard was published to prevent caused by systematic errors. Recently, the issue of external environmental factors rather than mechanical failure has increased. This issue is a problem outside of the scope of ISO 26262, and the ISO/DIS 21448 standard was published to solve this problem. Also, Mobileye proposed the RSS model that defined safe distance for dangerous situations in order to secure the safety of autonomous vehicles and who is responsible in case of an accident. In this paper, integrated process of ISO 21448 and RSS model, and through these results, we expect that possible to contribute to securing the safety and reliability of autonomous vehicles in the future.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.575-584
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• 2021

This study contains the process of developing a Mission Planning System (MPS) of an USV that can be applied in real situations and verifying them through HILS. In this study, we set the scenario of a single USV with limited operating time. Since the USV may not perform some missions due to the limited operating time, an objective function was defined to maximize the Mission Achievement Rate (MAR). We used a genetic algorithm to solve the problem model, and proposed a method using a 3-D population. The simulation showed that the probability of deriving the global optimal solution of the mission planning algorithm was 96.6% and the computation time was 1.6 s. Furthermore, USV showed it performs the mission according to the results of the MPS. We expect that the MPS developed in this study can be applied to the real environment where USV performs missions with limited time conditions.

• Journal of The Korean Association For Science Education
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• v.29 no.3
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• pp.291-303
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• 2009

According to social constructivism, group interaction is very important when students construct their knowledge. Many researchers have developed methods of teaching on the basis of group interaction because they recognized the importance of group interaction. There are a large variety of issues related to group interaction including group size, the gender and ability composition of groups, seating arrangements, textbook use, gestures, and role assignments. However, research on group interaction in science learning is still insufficient. In this study, we focused upon the emerging role of the primary leader. We investigated the primary leader's diverse role when students are solving mechanics problems. The participants were one group composed of three students in an upper-level mechanics class. To analyze these students' group interactions, their verbal interactions during meetings were videotaped and audiotaped during one-semester period. We also conducted interviews with the three students and analyzed their reports. As a result, we could find a special student who had the role of primary leader. We could also find the leader's three different leadership roles in different problem situations by inductively; explainer, facilitator and evaluator. Group interaction had different aspect according to the different role of leaders. The group interactions were the most active when the leader played the role of facilitator.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.92-99
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• 2024

To minimize the cumulative radiation dose, various path-finding approaches for single agent have been proposed. However, for emergence situations such as nuclear power plant accident, these methods cannot be effectively utilized for evacuating a large number of workers because no multi-agent method is valid to conduct the mission. In this study, a novel algorithm for solving the multi-agent path-finding problem is proposed using the conflict-based search approach and the objective function redefined in terms of the cumulative radiation dose. The proposed method can find multi paths that all agents arrive at the destinations with reducing the overall radiation dose. To verify the proposed method, three problems were defined. In the single-agent problem, the objective function proposed in this study reduces the cumulative dose by 82% compared with that of the shortest distance algorithm in experiment environment of this study. It was also verified in the two multi-agent problems that multi paths with minimized the overall radiation dose, in which all agents can reach the destination without collision, can be found. The method proposed in this study will contribute to establishing evacuation plans for improving the safety of workers in radiation-related facilities.

• Journal of The Korean Association For Science Education
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• v.26 no.7
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• pp.835-842
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• 2006

The aims of this study are to investigate how Kepler found a scientific problem for the retinal image theory and how abductive reasoning was used in his theory development, and to find implications for teaching creativity in science class from his thinking processes in the scientific discovery. Through the analysis of the related literatures, it was found that Kepler's problem finding in his retinal image theory came from the critical analysis of contemporary theories of vision, based on his relevant knowledge of optics, as he formulated his own hypothesis to build a new theory in eye vision employing optical phenomenon in spherical lens, which is a kind of abductive reasoning. From the results, three suggestions are proposed, that: (a) in the development of creativity teaching material, the situations like Kepler's problem finding need to be included in the programs; (b) it should be taught that relevant scientific knowledge is important for problem finding and hypothesis formulating; and (c) the experience of successful problem solving by themselves could help them find new scientific problem(s).

• Communications of Mathematical Education
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• v.30 no.2
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• pp.161-178
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• 2016

Mathematics problem based learning(PBL), which has recently attracted much attention, is a teaching and learning method to increase mathematical ability and help learning mathematical concepts and principles through problem solving using students' mathematical prerequisite knowledge. In spite of such a quite attention, it is not easy to apply and practice PBL actually in school mathematics. Furthermore, the recent instructional situations or environments has focused on student's self construction of their learning and its process. Because of this reason, to whom is related to mathematics education including math teachers, investigation and recognition on the degree of students' acquisition of mathematical thinking skills and strategies(for example, inductive and deductive thinking, critical thinking, creative thinking) is an very important work. Thus, developing mathematical thinking skills is one of the most important goals of school mathematics. In particular, recently, connection or integration of one subject and the other subject in school is emphasized, and then mathematics might be one of the most important subjects to have a significant role to connect or integrate with other subjects. While considering the reason is that the ultimate goal of mathematics education is to pursue an enhancement of mathematical thinking ability through the enhancement of problem solving ability, this study aimed to implement basically what is the meaning of the integrated thinking ability in problem based learning theory in Mathematics. In addition, using historical materials, this study was to develop mathematical materials and a sample of a concrete instructional guideline for enhancing integrated thinking ability in problem based learning program.

• The Journal of the Korea Contents Association
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• v.18 no.2
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• pp.334-343
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• 2018

The purposes of this study were to examine the general tendency of knowledge and problem solving abilities of children to cope with climate change and to find out whether there is a difference in the ability to cope with climate change based on the gender and age of young children. For this purpose, 129 children aged 5 and 6 who are attended in day care center in Seoul and Gyeonggi area were selected. We used 10 questions to measure climate change response knowledge modified environment conservation knowledge checklist and used five problem solving situations to measure climate change response problem solving ability modified safety problem solving ability test item. The collected data were analyzed using mean, standard deviation, two-way ANOVA, and Pearson's correlation coefficient. As a result, 6-year-old children's knowledge of climate change response and ability to solve climate change problems was higher than that of 5-year-olds. There was no gender difference in knowledge of climate change response and ability to solve climate change. The higher the knowledge level of children's response to climate change, the higher their ability to solve climate change response problems. The results of this study confirmed the association between children's knowledge of climate change response and problem solving ability and showed that a more systematic curriculum for improving knowledge and problem solving ability for preventing climate change needs to be provided to children.

• Journal of the military operations research society of Korea
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• v.8 no.2
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• pp.17-30
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• 1982

This paper offers an optimal artillery deployment scheme for the defending unit when two forces are confronted at a military front line. When proposed gun sites, types and number of guns as well as targets are given, the solutions of the two models in this paper direct each (unit of) guns to a certain location. The aim of the models is to maximize the number of guns which can hit important targets. Unlike widely used target assignment models, these models are formulated using the set covering problem concept. These models do not contain probabilities and time. Thus they are simple as models, easy in implementation, and yield tractable solutions. The dynamic and probabilistic feature of battle situations is implicitly reflected on the models. The first model is for the case that enemies' approaching route is clearly predictable, while the second model is for the unpredictable approaching route case.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.1
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• pp.59-66
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• 1996

In this paper, we present a new effective algorithm for element failure compensation of Generalized Sidelobe Canceller (GSC). While the GSC is well formulated, little works have been done on array element compensation in the presence of faulty elements. Element failure changes the problem of a linearly equally spaced array into that of an unequally spaced array. Typical research approaches have been directed at using search techniques to optimize unequally spaced arrays. The proposed algorithm matches the linear constraint conditions and the general shape of the desired beam pattern at the expense of an increase of beam-width in the overall main lobe. Numerical results are included to demonstrate the capability of compensation for various situations.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.485-496
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• 1997

To develop an Enterprise Data Model in Information Strategy Planning, it is essential that we first decide on the critical entities that need to be consistently managed in the enterprise. Identifying entities is a very crucial decision that has much influence on the subsequent phases in Information Engineering. Nevertheless, it is very subjective and usually depends on a decision makers experience and his/her own knowledge. In this paper, we propose a decision support system called CB*IMSS, which employs Case-Based Reasoning as the problem solution technique. By retrieving, analyzing and adapting some similar previous cases with a decision makers enterprise situations, this system can help them identify and decide the critical entities required for successful performance of the ISP.