• Education of Primary School Mathematics
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• v.3 no.1
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• pp.55-62
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• 1999

Through our elementary school mathematics, measurement is a critical topic since measurement helps connect ideas within areas of mathematics and between mathematics and other disciplines. In grade 4, students should understand angle, time, perimeter and area of figures by active involving. The paper gives ten ideas about teaching these concepts.

• Korean Institute of Interior Design Journal
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• v.24 no.6
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• pp.221-228
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• 2015

This study aims to define concepts on Hospital Design Focused on System to respond to the development and change by comparing general design methods of the General hospital architecture in Korea and analyze elements suitable to concepts on Hospital Design Focused on System in the General hospital architecture through examining the transformation of General hospitals in Korea. Essential architectural elements composing the Hospital Design Focused on System are as follows. First of all, the elements which can react to development of hospital architecture are HOSPITAL STREET and site situation. Secondly, core, equipment shaft, column, MAIN STREET and air handling unit room are elements of great importance as the location of these elements determines the dimensions and scale of the space which hospital functions are assigned to. Third, the area in regard to the rate of change is formed by MAIN STREET, which is the primary element, and envelope. The depth between MAIN STREET and envelope is defined as space depth. The flexible area is determined depending on this space depth and thus how to set up this flexible area determines the degree of readiness in responding to the change.

• School Mathematics
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• v.4 no.2
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• pp.283-296
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• 2002

In this study we tried to find the method of using the tangrams and the mosaic puzzles together for learning the elementary geometry in the Korean primary schools. The tangram and the mosaic puzzle activity-panels were developed and the activity-cards for them also were designed. The criteria to be used for the analyses of contents of the activity-cards were developed. We surveyed and analyzed the students' responses, A previous research had insisted that solely using the tangrams were not useful in learning about an obtuse-angled triangle in the elementary geometry (Welchman, 1999), but the combinative uses of the tangrams and the mosaic puzzles were found to extend the limits of the previous study in investigating the figures of the plain diagrams. Actually, the tangrams and the mosaic puzzles helped the students to learn the concepts of several elements of the plain diagrams such as 'angles', 'sides', and 'angular points', with students'operational comparison of the diagrams developed with them. They also provided useful clues in learning the relationship between the 'length' and the 'area' of the Plain diagrams. The students participated in the class with much activities, using the operational learning materials. They also comprehended the concepts and the principles of the elementary geometry more thoroughly, expressing their ideas in spoken or written languages through interactive communication. In conclusion, the tangram and mosaic puzzles can be used for learning the elementary geometry of the primary school level as motivative learning materials, helping students enhance diverse mathematical thinking and discover mathematical principles.

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.893-905
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• 2016

Numerous advanced reactor concepts have been proposed to replace light water reactors ever since their establishment as the dominant technology for nuclear energy production. While most designs seek to improve cost competitiveness and safety, the implausibility of doing so with affordable materials or existing nuclear fuel infrastructure reduces the possibility of near-term deployment, especially in developing countries. The organic nuclear concept, first explored in the 1950s, offers an attractive alternative to advanced reactor designs being considered. The advent of high temperature fluids, along with advances in hydrocracking and reforming technologies driven by the oil and gas industries, make the organic concept even more viable today. We present a simple, cost-effective, and safe small modular nuclear reactor for offshore underwater deployment. The core is moderated by graphite, zirconium hydride, and organic fluid while cooled by the organic fluid. The organic coolant enables operation near atmospheric pressure and use of plain carbon steel for the reactor tank and primary coolant piping system. The core is designed to mitigate the coolant degradation seen in early organic reactors. Overall, the design provides a power density of 40 kW/L, while reducing the reactor hull size by 40% compared with a pressurized water reactor while significantly reducing capital plant costs.

• School Mathematics
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• v.2 no.1
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• pp.203-241
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• 2000

This study aims to suggest a model of task development for mathematics performance assessment and to develop performance tasks for the fifth graders in the primary school on the basis of this model. In order to achieve these aims, the following inquiry questions were set up: (1) to develop open-ended tasks and projects for the fifth graders, (2) to develop checklists for measuring the abilities of mathematical reasoning, problem solving, connection, communication of the fifth graders more deeply when performance assessment tasks are implemented and (3) to examine the appropriateness of performance tasks and checklists and to modify them when is needed through applying these tasks to pupils. The consequences of applying some tasks and analysing some work samples of pupils are as follows. Firstly, pupils need more diverse thinking ability. Secondly, pupils want in the ability of analysing the meaning of mathematical concepts in relation to real world. Thirdly, pupils can calculate precisely but they want in the ability of explaining their ideas and strategies. Fourthly, pupils can find patterns in sequences of numbers or figures but they have difficulty in generalizing these patterns, predicting and demonstrating. Fifthly, pupils are familiar with procedural knowledge more than conceptual knowledge. From these analyses, it is concluded that performance tasks and checklists developed in this study are improved assessment tools for measuring mathematical abilities of pupils, and that we should improve mathematics instruction for pupils to understand mathematical concepts deeply, solve problems, reason mathematically, connect mathematics to real world and other disciplines, and communicate about mathematics.

• Education of Primary School Mathematics
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• v.21 no.2
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• pp.209-221
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• 2018

Angle concepts have a multifaceted nature such as quantitative aspects as the amount of rotation, qualitative aspects as geometric shapes, and relationship aspects made with planes or lines. This study analysed angle concepts and introduction methods of angles in elementary mathematics textbooks which have been used from the Syllabus Period to the 2015 Revised Mathematics Curriculum. First, the concepts of angles in mathematics textbooks focus through the definitions, representations, and components of angles presented in mathematics textbooks are analyzed. Secondly, how various aspects of each angle are sequenced through the tasks or activties in the introduction of lesson is looked. As a result of analysis, the methods of introducing angles in the changes of mathematics textbooks have mainly focused on learning about geometric shapes and relations of components. In the mathematics classroom, students should experience various aspects of geometric shapes, rotations, relational aspects of points, lines and surfaces, and support and link them to form a wide range of concepts.

• School Mathematics
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• v.19 no.1
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• pp.1-18
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• 2017

In this study we analyse the features of process of problem posing and explore the development of mathematical knowledge of primary preservice teachers as result of their engagement in problem posing activity. Data was collected through the preservice teachers' class discussions. Analysis of the data shows that preservice teachers developed their ability to understand connections among mathematical concepts.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.12 no.2
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• pp.31-38
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• 2003

Amelogenesis imperfecta patients suffered common clinical problems of poor esthetics, teeth sensitivity, and loss of occlusal vertical dimension. Amelogenesis imperfecta is a group of inherited disorders primarily affecting dental enamel. Variants of amelogenesis imperfecta generally classified hypoplastic, hypocalcified, or hypomaturation types based on the primary enamel defects. The mildest problems were found in the pitted hypoplastic type whereas the most severe problems were encountered in the hypocalcified type amelogenesis imperfecta. Management stragies include composite resin veneer and jacket crowns for anterior teeth as well as steel crowns for posterior teeth. Knowledge of the clinical features and dental complications of each variants if amelogenesis impecta helps in the diagnosis of the condition and allows institution of early preventive measures. The objective of this paper is to provide a review of the current concepts of the wide spectrum of etiological factors involved in the pathogenesis of this significance clinical entity in the primary dentition.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.4 no.2
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• pp.1-6
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• 2008

Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source for nuclear hydrogen generation. The VHTR can produce hydrogen from heat and water by using a thermo-chemical process or from heat, water, and natural gas by steam reformer technology. A co-axial double-tube primary hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the VHTR. In this study, a preliminary design analysis for the primary HGD of the nuclear hydrogen system was carried out. These preliminary design activities include a determination of the size, a strength evaluation and an appropriate material selection. The determination of the size was undertaken based on various engineering concepts, such as a constant flow velocity model, a constant flow rate model, a constant hydraulic head model, and finally a heat balanced model.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.3
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• pp.264-270
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• 2011

A new method for creating a logical data model is proposed. The logical data model developed by the method defines table, primary key, foreign key, and fields. The framework of the logical data model is constructed by modeling the relationships between events and their related entity types. The proposed method consists of a series of objective and quantitative decisions such as maximum cardinality of relationships and functional dependency between the primary key and attributes. Even beginners to database design can use the methology as long as they understand such basic concepts about relational databases as primary key, foreign key, relationship cardinality, parent-child relationship, and functional dependency. The simple and systematic approach minimizes decision errors made by a database designer. In practial database design the method creates a logical data model in Boyce-Codd normal form unless the user of the method makes a critical decision error, which is very unlikely.