• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.933-940
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• 2024

A macroscopic cross section generation model was developed for the conceptual horizontal, compact high temperature gas reactor (HC-HTGR). Because there are many sources of spectral effects in the design and analysis of the core, conventional LWR methods have limitations for accurate simulation of the HC-HTGR using a neutron diffusion core neutronics simulator. Several super-cell model configurations were investigated to consider the spectral effect of neighboring cells. A new history variable was introduced for the existing library format to more accurately account for the history effect from neighboring nodes and reactivity control drums. The macroscopic cross section library was validated through comparison with cross sections generated using full core Monte Carlo models and single cell cross section for both 3D core steady-state problems and 2D and 3D depletion problems. Core calculations were then performed with the AGREE HTR neutronics and thermal-fluid core simulator using super-cell cross sections. With the new history variable, the super-cell cross sections were in good agreement with the full core cross sections even for problems with significant spectrum change during fuel shuffling and depletion.

• Journal of The Korean Association For Science Education
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• v.31 no.5
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• pp.734-744
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• 2011

The purpose of this study was to identify middle school students' mental models on plate tectonics and to compare the mental models of verbal-learning-style students with those of visual-learning-style students. 94 student participants in 9th grade were requested to draw and explain three topics; generation of magma, the formation of the mountain range and the interior of the Earth. The criterions for analyzing the mental models are derived from the data of the drawing task. The research results were as follows: The mental models on the generation of magma were classified as 'unstable model,' 'partial casual model,' 'causal model,' and 'conceptual model.' On the other hand, the mental models on the interior of the Earth were classified as 'static unstable model,' 'dynamic unstable model,' and 'conceptual model.' Students holding 'unstable model' were unable to relate the plate collision and the magma generation. They showed a variety of alternative conceptions of study areas, such as 'magma is generated from the core' and 'the mountain is formed by rising of the plates themselves.' Also, visual-learning-style students showed higher proportion of conceptual models and lower proportion of unstable mental models than verbal-learning-style students on three topics. The findings revealed that the students tend to have different concepts on the plate tectonics depending on their learning style.

• Korean Journal of Construction Engineering and Management
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• v.5 no.4 s.20
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• pp.79-86
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• 2004

One of the most difficult tasks in pavement management information systems is establishing the links between performance measures of a structure and the design and construction inputs. In-situ pavement performance can be considered a response variable to many project input variables, such as design, construction, and traffic loading effects. If we are to fully understand the component of pavement performance and specify the inputs through design and construction specifications to achieve that performance we must develop quantitative relationship between input and response variables through a scientific, fully integrated Pavement Performance Analysis System (PPAS). Hence, the objective of this study is to design a database model required for developing an effective database template that will allow analysis of pavement performance measures based on design and construction information linked by location. In order to select the most appropriate database model, a conceptual database model (Entity Relationship Model) and dimensional model, which is believed to be the most effective modeling technique for data warehouse project, are designed and compared. It is believed that other state highway agencies could adopt the proposed design strategy for implementing a PPAS at the discretion of the state highway agencies.

• Journal of The Korean Association For Science Education
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• v.22 no.5
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• pp.1044-1070
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• 2002

Initial science teacher education in Hong Kong is provided by the Post-graduate Diploma in Education Programme (PGDE) for both pre-service and in-service secondary school teachers. This programme includes a balanced treatment of subject curriculum and teaching in science, general pedagogical knowledge and skills, educational psychology and school administration. The science courses in this programme also have some units that equip science teachers with the knowledge and skills that are essential for teaching a science curriculum that emphasises conceptual change and understanding of the nature and methods of science. This emphasis is illustrated by two studies: (1) Developing a conceptual change model of instruction in Biology teachers, and (2) Constructing understanding of the nature and methods of science.

• Korean Journal of Chemical Engineering
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• v.35 no.12
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• pp.2348-2354
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• 2018

We designed a conceptual model of the 2.3-BDO dehydration process using a hydroxyapatite-alumina catalyst and estimated its economic feasibility to predict the appropriate range of the purchase price of 2,3-BDO on commercial scale. The conceptual design and economic analysis can offer valuable information for the industrial application of 2,3-BDO because the most relevant studies have limitation in laboratory scale. Furthermore, the adequate range of 2,3-BDO price, in which the process has profitability, was investigated with the current market prices of 1,3-BD. The investigated price in terms of 2,3-BDO dehydration can pertain to estimation of the economic feasibility in 2,3-BDO production process.

• Advances in aircraft and spacecraft science
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• v.8 no.4
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• pp.331-344
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• 2021

Airframe internal and external specifications are the product of intensive intellectual efforts and technological breakthroughs distinguishing each aircraft manufacturer. Therefore, geometrical information characterizing aircraft primary aerodynamic surfaces remain classified. When attempting to model real aircraft, many members of the aeronautical community depend on their personal expertise and generic design principles to bypass the confidentiality obstacles and sketch real aircraft airfoils, which therefore vary for the same aircraft due to the different designers' initial assumptions. This paper presents a photogrammetric shape prediction method for deriving geometrical properties of real aircraft airframe by utilizing their publicly accessible static and dynamic visual content. The method is based on extracting the visually distinguishable curves at the fairing regions between aerodynamic surfaces and fuselage. Two case studies on B-29 and B-737 are presented showing how to approximate the sectional coordinates of their wing inboard airfoils and proving the good agreement between the geometrical and aerodynamic properties of the replicated airfoils to their original versions. Therefore, the paper provides a systematic reverse engineering approach that will enhance aircraft conceptual design and flight performance optimization studies.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2446-2451
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• 2000

This paper presents the conceptual model of open & distributed intelligent control network for BAS. The characteristics and definition of this network also is proposed from theoretical study of LonWorks and a comparison between LonWorks and conventional network.

• Journal of the Korean housing association
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• v.22 no.1
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• pp.43-55
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• 2011

The purpose this study is to develop indicators that measure the healthy housing condition of multi-family housing. The major findings are as follow: first, healthy housing was defined by physical, mental, social, and management aspects and proposed the conceptual model of hierarchy structure of evaluation of healthy housing by literature reviews. Second, evaluating items were selected based on literature reviews of existing indicators and preceding studies about both domestic and overseas multi-family housing. The evaluating indicators were identified as a total of 87 evaluating items which were composed of four dimensions and 16 attributes on the basis of the conceptual model. They cover comprehensive scope of the multi-family housing such as unit, building, complex, and site. Third, as the measurement, the 5-point ordinal scale measure was suggested. The evaluating measurement including measure standards, measure methods, and measure contents were developed by each evaluating items. Lastly, the weighting of evaluating indicators was developed by AHP method conducted by survey of an expert group. Items were identified as high contributors or low contributors. The weighting of these items could suggest several evaluations according to the situation. The level of healthy housing condition may be evaluated by both total evaluation and a specific field of evaluation.

• Journal of the Korean Society of Systems Engineering
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• v.19 no.1
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• pp.44-55
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• 2023

The defense M&S system, which has been classified as a weapon system between requirements determination and project implementation, is being developed by applying the weapon system development procedure of the Defense Acquisition Program Administration. The M&S system abstracts and models the real world to suit the intended use and proceeds with the process of developing it as a software-oriented system. Overseas, the conceptual model development stage is staged before entering the design stage after the requirements analysis. In addition, each step includes verification and validation processes. In Korea, while establishing and applying the weapon system development procedure based on the SE process, the M&S system is also applied in the same way as the general weapon system, limiting appropriate development outputs and verification and validation. In this study, the system development procedure of the M&S system is established and presented based on the relevant standards and SE process of developed countries.

• Korean Management Science Review
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• v.11 no.2
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• pp.43-63
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• 1994

A new model management framework is proposed to accommodate wide-spreading algebraic modeling languages (AMLs), and to facilitate a full range of model manipulation functions. To incorporate different modeling conventions of the leading AMLs (AMPL, GAMS, and SML) homogeneously, generic model concepts are introduced as a conceptual basis and are embodied by the structural and operational constructs of an Object-Oriented Database Management System(ODBMS), enabling the framework to consolidate components of DSSs(database, modelbase, and associated solvers) in a single formalism effectively. Empowered by a database query language, the new model management framework can provide uniform model management commands to models represented in different AMLs, and effectively facilitate integration of the DSS components. A prototype system of the framework has been developed on a commercial ODBMS, ObjectStore, and a C++ programming language.