• Nuclear Engineering and Technology
• /
• v.52 no.12
• /
• pp.2743-2759
• /
• 2020

A detailed computational fluid dynamics (CFD) simulation analysis model was developed using ANSYS CFX 16.1 and analyzed to simulate the basic design and internal flow characteristics of a 180 MW small modular reactor (SMR) with a natural circulation flow system. To analyze the natural circulation phenomena without a pump for the initial flow generation inside the reactor, the flow characteristics were evaluated for each output assuming various initial powers relative to the critical condition. The eddy phenomenon and the flow imbalance phenomenon at each output were confirmed, and a flow leveling structure under the core was proposed for an optimization of the internal natural circulation flow. In the steady-state analysis, the temperature distribution and heat transfer speed at each position considering an increase in the output power of the core were calculated, and the conceptual design of the SMR had a sufficient thermal margin (31.4 K). A transient model with the output ranging from 0% to 100% was analyzed, and the obtained values were close to the T_hot and T_cold temperature difference value estimated in the conceptual design of the SMR. The K-factor was calculated from the flow analysis data of the CFX model and applied to an analysis model in RELAP5/MOD3.3, the optimal analysis system code for nuclear power plants. The CFX analysis results and RELAP analysis results were evaluated in terms of the internal flow characteristics per core output. The two codes, which model the same nuclear power plant, have different flow analysis schemes but can be used complementarily. In particular, it will be useful to carry out detailed studies of the timing of the steam generator intervention when an SMR is activated. The thermal and hydraulic characteristics of the models that applied porous media to the core & steam generators and the models that embodied the entire detail shape were compared and analyzed. Although there were differences in the ability to analyze detailed flow characteristics at some low powers, it was confirmed that there was no significant difference in the thermal hydraulic characteristics' analysis of the SMR system's conceptual design.

• Journal of The Korean Association For Science Education
• /
• v.22 no.2
• /
• pp.357-377
• /
• 2002

This study is for better understanding about the process of students' conceptual change. As a starting point, it is assumed that the process of students' conceptual change can be viewed as the process of the successive refinement and articulation of students' conceptual framework. Based on the theoretical review of conceptual change literature, various processes, which can be involved in the above assumed process, can be found. And also, by analyzing the process of development of scientific knowledge about Planck's blackbody radiation law and Bohr's atom, six types of processes of refinement and articulation of scientific knowledge can be found. It is hoped that these theoretical discussions can guide the direction for obtaining and interpreting the students' real responses during the process of conceptual change.

• The Mathematical Education
• /
• v.47 no.1
• /
• pp.11-25
• /
• 2008

The characteristics of the pseudo-conceptual or the pseudo-analytical behaviors according to the achievement level(i.e. advanced group, proficient group, basic group, and below-basic group) in grade 9 are as follows. The pseudo-conceptual or pseudo-analytical behaviors to get credit from teachers become conspicuous in lower achievement level. The high achieving students showed more pseudo-conceptual or pseudo-analytical behaviors without undergoing the process of reflection or control. The proficient group was short of control in computation, and the advanced group didn't control well in representation. The proficient group tended to depend on a past successful algorithm and behave habitually. Therefore, it is needed to teach mathematics according to the characteristic of pseudo-conceptual or pseudo-analytic behaviors shown in each achievement level.

• Journal of the military operations research society of Korea
• /
• v.31 no.2
• /
• pp.105-115
• /
• 2005

To ensure interoperability among TADILs, we need inter-operational system of tactical data link that allows sharing of specific, planned information among different TADILs. In this paper, we have proposed the design of a conceptual software architecture of inter-operational system. For developing of a conceptual software architecture, we analyze the actual condition of ADSI used in the US military and identify functions and quality-attributes. Based on these factors, we design the conceptual software architecture for inter-operational system of tactical data link using Attribute-Driven Design(ADD) method. ADD is consist of three phases - choose the module to decompose, refine the module, repeat the steps for every module that needs further decomposition. To evaluate of ADD results, we apply the Software Architecture Analysis Method(SAAM) which is consist of making evaluation scenarios, choosing indirect scenarios, evaluation scenarios' interaction, and creating an overall evaluation. Through the evaluation, we verify the conceptual software architecture of inter-operational system.

• International Journal of Computer Science & Network Security
• /
• v.21 no.3
• /
• pp.153-164
• /
• 2021

The increasing importance of such fields as embedded systems, pervasive computing, and hybrid systems control is increasing attention to the time-dependent aspects of system modeling. In this paper, we focus on modeling conceptual time. Conceptual time is time represented in conceptual modeling, where the notion of time does not always play a major role. Time modeling in computing is far from exhibiting a unified and comprehensive framework, and is often handled in an ad hoc manner. This paper contributes to the establishment of a broader understanding of time in conceptual modeling based on a software and system engineering model denoted thinging machine (TM). TM modeling is founded on a one-category ontology called a thimac (thing/machine) that is used to elaborate the design and analysis of ontological presumptions. The issue under study is a sample of abstract modeling domains as exemplified by time. The goal is to provide better understanding of the TM model by supplementing it with a conceptualization of time aspects. The results reveal new characteristics of time and related notions such as space, events, and system behavior.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.11
• /
• pp.1458-1469
• /
• 2004

In this study, color names focusing on the purple series, appearing in the clothing of the Joseon Dynasty, were classified systematically, and the conceptual meaning of each name were investigated through various methods. The results are as follows; First, the color names of purple-series were classified systematically. According to the integration scheme of morphemes, color names could be divided into two categories; single names and composite names. Color names could also be classified into universal and limited names according to the areal distribution of literatures. Secondly, the conceptual meaning of the color names of purple-series were considered. The conceptual meaning could be divided into two categories; one 'etymological and dyeing methodological meaning', the other 'color systematic meaning' By studying the dictionary definition of color names, comparing and analyzing the material composition of colors, the etymological and dyeing methodological meaning could be grasped. Furthermore, the color systematic meaning of each name could be grasped through the cluster analysis of L*, a*, b* values measured from the relics of clothing. Thirdly, the conceptual semantic structure were established on the basis of conceptual meanings of purple-series color names. The conceptual semantic structure of purple-series color names is forming discrete structure with the dyeing method and material of dyes as their semantic components.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.910
• /
• pp.1253-1264
• /
• 2004

The purpose of this study is to develop clothing shopping orientation[CSO] scale reflecting the conceptual structure of CSO. For this purpose, a questionnaire composed of comprehensive 85 CSO items was developed through 2-step preliminary tests. Data was collected from two samples. One sample(n=559) was for scale development and the other sample(n=235) was for cross validity test. Descriptive analysis, correlation analysis, exploratory factor analysis, regression analysis, ANOVA, and confirmatory factor analysis were used for data analysis. For each lower-dimension within the CSO conceptual structure model, 1-2 items were selected based on the quantitative and the qualitative standards. As a result, a CSO scale composed of 31 items was developed, and reliability, construct validity, cross validity, convergent validity, discriminant validity, and criterion validity of the scale were verified. This study has significance in offering the standardized scale to both the academic and the practical fields.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.29 no.3_4 s.141
• /
• pp.535-546
• /
• 2005

The purposes of this study are to verify the validity of the conceptual structure of clothing shopping orientation(CSO) developed in the previous research, and to explore the difference of CSO structure between male and female consumer groups. For those purposes, data of 499 male and female consumers were collected. Confirmatory factor analysis, ANOVA, and simultaneous factor analysis were used for data analysis. The results are as follows. First, as a result of confirmatory factor analysis, the validity of conceptual structure of CSO was verified. Second, as a result of ANOVA, male and female showed significantly different CSO at the lower-dimensions level, and as a result of simultaneous factor analysis, male and female showed significantly different relationships between dimensions within the structure. This means that the CSOs of both male and female can be explained by the same CSO structure model, but the specific relationships between CSO dimensions are different by the gender of consumers. Finally, directions for fashion marketing mix concerning the CSO structures of male and female were suggested.

• International Journal of Advanced Culture Technology
• /
• v.11 no.4
• /
• pp.255-262
• /
• 2023

The purpose of this study was to clarify the concept of LGBT cultural competence in nurses. This study used Walker and Avant's 8 steps of conceptual analysis. The specific steps are: (1) selecting the concept, (2) selecting the purpose of concept analysis, (3) identifying the scope of concept use, (4) identifying the determinant attributes of the concept, (5) presenting model cases, (6) additional cases of the concept (boundary cases, opposite cases, and related cases), (7) identifying antecedents and consequences, and (8) presenting empirical evidence. As a result, five attributes of nurses' LGBT cultural competence were identified in the final 12 articles: cultural experience and cultural acceptance, cultural knowledge, cultural attitude and awareness, and cultural skills. Antecedents included diversification of society, heteronormative healthcare environment, continuing education and training, intercultural understanding, and open-mindedness. Outcomes of cultural competence were identified as reducing LGBT health inequalities and providing quality care. In conclusion, this study contributes to providing a basis for improving the quality of nursing care by providing more culturally appropriate care to the target population through conceptual analysis and understanding of nurses' LGBT cultural competence. Furthermore, it is necessary to continue research on the development of tools to measure nurses' LGBT cultural competence and the development of nursing intervention programmes that can be applied in nursing practice.

• International Journal of Aeronautical and Space Sciences
• /
• v.16 no.4
• /
• pp.624-635
• /
• 2015

Design space exploration has been much neglected in aircraft conceptual design phase, which often leads to a waste of time and cost in design, manufacture and operation process. It is necessary to explore design space based on operational system-of-systems (SoS) simulation during the early phase for a competitive design. This paper proposes a methodology to analyze aircraft performance parameters in four steps: combination of parameters, object analysis, operational simulation, and key-parameters analysis. Meanwhile, the design space of an unmanned aerial vehicle applied in earthquake search and rescue SoS is explored based on this methodology. The results show that applying SoS simulation into design phase has important reference value for designers on aircraft conceptual design.