• Bulletin of the Korean Mathematical Society
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• v.55 no.5
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• pp.1433-1440
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• 2018

We study the polarity of cohomogeneity two isometric actions on Riemannian manifolds of constant negative curvature.

• Journal of Ocean Engineering and Technology
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• v.20 no.4 s.71
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• pp.43-49
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• 2006

Detailed investigations were carried out on the stability of the dredged soil bed against wave actions, aimedat establishing the design method of artificial tidal flats using dredged soil. The soil was dredged at Nagoya port, Japan, and has a mean grain size of 0.013mm. Basic features of artificial dredged soil bed against wave actions were explained from a series of model experiments in a wave flume. The two types of section shapes were employed; one is a horizontal bed and the other is a sloped one. Changes of the bed profile, shear strength, grain size distribution and water content, according to the wave actions, were measured in detail. The cumulative effect of the wave actions, over about one week, was investigated. A dredged soil bed moves withthe wave actions with relatively small wave height. It should be especially. noted that the clay component is dissolved and flown out, away from the surface layer, and consequently the surface layer hardens, as if it is covered with sand. Wren the wave height is gradually increased, the bed is not liquefied and the shear strength of the dredged bed is increased by a wave-induced dissipation of pore pressures in the bed and a decrease of clay component by the wave-induced leakage.

• Communications of the Korean Mathematical Society
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• v.21 no.2
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• pp.337-345
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• 2006

John Harer conjectured that the canonical map from braid group to mapping class group induces zero homology homomorphism. To prove the conjecture it suffices to show that this map preserves the first Araki-Kudo-Dyer-Lashof operation. To get information on this homology operation we need to investigate the image of braiding under the Harer map. The main result of this paper is to give both algebraic and geometric interpretations of the image of braiding under the Harer map. For this we need to calculate long chains of consecutive actions of Dehn twists on the fundamental group of surface.

• Wind and Structures
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• v.37 no.2
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• pp.133-151
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• 2023

This paper first provides a wide overview about the design codes and standards covering the use of Computational Wind Engineering / Computational Fluid Dynamics (CWE/CFD) for wind-sensitive structures and built environment. Second, the paper sets out the basic assumptions and underlying concepts of the new Annex T "Simulations by Computational Fluid Dynamics (CFD/CWE)" of the revised version "Guide for the assessment of wind actions and effects on structures" issued by the Advisory Committee on Technical Recommendations for Constructions of the Italian National Research Council in February 2019 and drafted by the members of the Special Interest Group on Computational Wind Engineering of the Italian Association for Wind Engineering (ANIV-CWE). The same group is currently advising UNI CT021/SC1 in supporting the drafting of the new Annex K - "Derivation of design parameters from wind tunnel tests and numerical simulations" of the revised Eurocode 1: Actions on structures - Part 1-4: General actions - Wind actions. Finally, the paper outlines the subjects most open to development at the technical and applicative level.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.16-26
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• 2020

Improving operator performance in complex and time-critical situations is critical to maintain plant safety and operability. These situations require quick detection, diagnosis, and mitigation actions to recover from the root cause of failure. One of the key challenges for operators in nuclear power plants is information management and following the control procedures and instructions. Nowadays Digital Twin technology can be used for analyzing and fast detection of failures and transient situations with the recommender system to provide the operator or maintenance engineer with recommended action to be carried out. Systems engineering approach (SE) is used in developing a digital twin for the CEDM system to support operator actions when there is a misalignment in the control element assembly group. Systems engineering is introduced for identifying the requirements, operational concept, and associated verification and validation steps required in the development process. The system developed by using a machine learning algorithm with a text mining technique to extract the required actions from limiting conditions for operations (LCO) or procedures that represent certain tasks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4498-4510
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• 2015

The purpose of this study is to investigate effective teaching media for infants' teaching-learning process by comparing the effects of multimedia fairytale activities and picture fairytale listening activities on infants' prosocial actions. Following the purpose of this study, we studied any effect to infants' prosocial actions from multimedia fairytale activities by dividing in two groups. This study was conducted with 5-year-old infants (total 40; 20 experimental group & 20 comparison group) in D daycare center in Daejeon. Verifying data tool were time series corresponding t-test, independent t-test and multi-variant analyses. As a result, multimedia fairytale listening activities are more effective for infants' prosocial actions. It has meaningful difference in the interpersonal relationship skills and early childhood education adapt which is sub-area of infant's prosocial actions. So, for various and high-quality early childhood education, using multimedia teaching media is more effective than existing teaching media.

• The Pure and Applied Mathematics
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• v.14 no.4
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• pp.307-315
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• 2007

We study crossed products of the free group and semigroup $C^*-algebras$ by actions of ${\mathbb{R}$, i.e., flows, and estimate and compute their stable rank.

• Journal of Technologic Dentistry
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• v.33 no.1
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• pp.65-77
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• 2011

Purpose: The purposes of this study were to provide information about safe actions during the practice of dental technology, promote belief in safe actions among the students of dental technology, and reinforce their knowledge about how to act safety. Methods: Open questions were asked to 120 sophomores majoring dental technology to understand the target group's belief about safe actions. Following the instructions by Ajzen & Fishbein, the collected data were grouped according to similar beliefs. Those beliefs of the highest frequency were given a priority and got to represent the belief level of the target group. Even with belief changes, however, they would not be able to practice safe actions if they had no knowledge about how to do safe actions. For desirable behavioral changes among the students, the students were then asked to discuss the current state of safety accidents and issues focusing on the materials and processes used in the practice and give presentations regarding the subjects to identify risk factors. Then the identified risk factors were used to devise the program contents so that the students could practice safe actions through accurate behavioral approaches and belief changes by educating them about how to act safely by the practice processes and the involved materials and devices. Results: Not only do the students of Dept. of Dental Technicians have difficulties with the complex practice processes while practicing to make dental prosthesis, but they are exposed to the risk of accidents as they're poor at dealing with the materials and devices. Although there is a definite need for accident prevention education programs before practice, the reality is that the school doesn't the schoosuch education. Based on the judgment that an education program designed to reinforce belief for behavioral changes would generate effgrams results, an education program was developed by applying the Theory of Planned Behavior(TPB). Along with their beliefs, the current state of accidents n. Basepractice, demand for safety education, and practice level of safe actions were used to device the contents of accident prevention education and to develop an accident prevention education program for dental technology. Conclusion: The study presents an accident prevention education program developed to reinforce dental technology students' beliefs and knowledge and to help them do safe actions during practice.

• Honam Mathematical Journal
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• v.13 no.1
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• pp.65-70
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• 1991

• Communications of the Korean Mathematical Society
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• v.5 no.1
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• pp.129-160
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• 1990