• Journal for History of Mathematics
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• v.17 no.3
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• pp.109-120
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• 2004

This study investigated three pre-service teachers' mathematical problem solving among hand-in-write-ups and final projects for each subject. All participants' activities and computer explorations were observed and video taped. If it was possible, an open-ended individual interview was performed before, during, and after each exploration. The method of data collection was observation, interviewing, field notes, students' written assignments, computer works, and audio and videotapes of pre- service teachers' mathematical problem solving activities. At the beginning of the mathematical problem solving activities, all participants did not have strong procedural and conceptual knowledge of the graph, making a model by using data, and general concept of a sine function, but they built strong procedural and conceptual knowledge and connected them appropriately through mathematical problem solving activities by using the computer technology.

• Journal of Sport and Applied Science
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• v.6 no.2
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• pp.19-25
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• 2022

Purpose: This study attempts to investigate causal and intervening conditions for sport participation of Korean immigrants in the United States. Research design, data, and methodology: Grounded theory approach was used to develop a conceptual framework that presents the psychosocial processes that occur in immigrants' experience of sport participation. Participants were selected purposefully for information-rich cases. Korean immigrants with current experience of having periodically participated in sports were the criterion for sample selection. Based on selection criteria, 9 Korean immigrants took part in interview. The interview discussions were taped and transcribed verbatim into a Word file. The process for data analysis included four grounded theory approaches of purposive and theoretical sampling, an open and axial coding, memo writing, and finally the development of the conceptual framework. Results: Six concepts were revealed in the causal conditions that facilitate the process of immigrants' sport participation in the states: Personal experience, significant others, personality, physical environment, psychological well-being, and social connection. Three concepts were revealed as the intervening conditions that block the process of immigrants' sport participation in the states: Conflict with cultural change of organization, Pressure at workplace, and Economic constraints. Conclusions: Conceptual model presents causal and intervening factors. Further implications were discussed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.126-132
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• 2004

The database design for the management of bridge measurement information is presented in this paper. To express the associated data generated during the whole process of ambient measurement efficiently, requirements analysis for database construction is performed. And to define objects and organize schema conceptual and logical design are performed, which convert data model into logical schema. Finally, physical design is performed using DDL(data defined language). This database is based on the object-relational data modeling approach that has rich expressive power and good reusability in comparison with the traditional entity-relational modeling.

• Journal of the Korean earth science society
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• v.39 no.2
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• pp.193-207
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• 2018

The purpose of this study was to analyze trends in conceptual change research in the field of Earth Science education conducted in Korea and to provide them as basic data of future concept change research. The trends of conceptual change research were analyzed in terms of keywords, year of publication, source of research, purpose of research, subject, area of research, and research method. This study was carried out on a total of 126 conceptual change papers of Earth Science education published from 1989 to July 2017. This study showed the following conclusions: First, the conceptual change research papers used more the term 'conceptual change' than 'misconceptions' and 'preconceptions'. Second, the conceptual change paper has achieved a large amount of growth in the 2000s. Third, conceptual change research tended to proceed to the subject of master's dissertation. Fourth, there were a lot of researches to find out the misconceptions and change them into the right concept, the conceptual change paper used free response test for misconceptions, and cognitive conflict instruction model and CAI (Computer Assisted Instruction) teaching strategy for misconceptions. Fifth, elementary school students were studied the most. Sixth, the study of conceptual changes in the field of Earth Science was high in the astronomical and atmospheric areas. Finally, although quantitative analysis methods were used in the early days of research, in the 2010s, qualitative analysis methods were widely used. In this paper, we proposed research on conceptual change for pre- and in-service teachers, expansion of research on conceptual changes in various fields such as geology, oceanography, atmosphere in Earth Science, investigation of causes of misconception in Earth Science and research on individual's affective factors, and so on.

• Journal of the Korean Society of Safety
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• v.34 no.3
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• pp.102-110
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• 2019

This paper describes the work and results of the preliminary Probabilistic Safety Assessment (PSA) for a research reactor in the design phase. This preliminary PSA was undertaken to assess the level of safety for the design of a research reactor and to evaluate whether it is probabilistically safe to operate and reliable to use. The scope of the PSA described here is a Level 1 PSA which addresses the risks associated with core damage. After reviewing the documents and its conceptual design, eight typical initiating events are selected regarding internal events during the normal operation of the reactor. Simple fault tree models for the PSA are developed instead of the detailed model at this conceptual design stage. A total of 32 core damage accident sequences for an internal event analysis were identified and quantified using the AIMS-PSA. LOCA-I has a dominant contribution to the total CDF by a single initiating event. The CDF from the internal events of a research reactor is estimated to be 7.38E-07/year. The CDF for the representative initiating events is less than 1.0E-6/year even though conservative assumptions are used in reliability data. The conceptual design of the research reactor is designed to be sufficiently safe from the viewpoint of safety.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1183-1188
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• 2009

Estimating project costs during the early stage of conceptual planning is very important when deciding whether to approve the project and allocate an appropriate budget. However, due to greater uncertainties involved in a project, it is challenging to estimate costs during this initial stage within a reasonable tolerance. This paper attempts to develop a cost-estimate model for public road projects under these circumstances and limitations. In the conceptual planning stage of a road project, there is only limited information for cost estimation, for example, such input data as total length of the route, origin and destination, number of lanes, general geographic characteristics of the route, and other basic attributes. This implies that the model should individuate suitable but restricted information without considering detailed features such as quantity of earthwork and a detailed route of a given condition. With these limited facts, this paper applies a case-based reasoning (CBR) method to solve a new problem by deriving similar past problems, which in turn is used to estimate the cost of a given project based on best-fitted previous cases. To develop a CBR cost-estimate model, the authors classified 8 representative variables, including project type, the number of lanes, total length, road design grades, etc. Then, we developed the CBR model, primarily by using 180 actual cases of public road projects, procured over the last decade. With the CBR model, it was found that the degree of error in estimation can be reasonably reduced, to below approximately 30% compared to the final costs estimated upon the completion of detailed design.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.178-181
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• 2003

The temporal GIS data modeling methods are discussed in this paper. At first, two conceptual models of spatio-temporal data are introduced, and then some typical STDMs based on these two models are summed up and compared. After that, the spatio-temporal changes are analyzed thoroughly, and then how to model spatio -temporal data from different aspects is discussed. At last, several issues that need further research are pointed out.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.417-424
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• 2009

For a construction project to progress smoothly, effective cost estimation is vital, particularly in the conceptual and schematic design stages. In these early phases, despite the fact that initial estimates are highly sensitive to changes in project scope, owners require accurate forecasts which reflect their supplying information. Thus, cost estimators need effective estimation strategies. Practically, parametric cost estimates are the most commonly used method in these initial phases, which utilizes historical cost data (Karshenas 1984, Kirkham 2007). Hence, compilation of historical data regarding appropriate cost variance governing parameters is a prime requirement. However, precedent practice of data mining (data preprocessing) for denoising internal errors or abnormal values is needed before compilation. As an effort to deal with this issue, this research proposed a statistical methodology for data preprocessing and verified that data preprocessing has a positive impact on the enhancement of estimate accuracy and stability. Moreover, Statistically Preprocessed data Based Parametric (SPBP) cost models are developed based on multiple regression equations and verified their effectiveness compared with conventional cost models.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.12 no.19
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• pp.89-98
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• 1989

This research addresses the most sophisticated level of complexity of current electronic data processing(EDP) technology realtime, distributed data base(DDB) system. The major objective is to develop guidelines for the control and audit of these sophisticated system, since the control and audit philosophies, control features, and audit techniques applicable to traditional EDP systems are no longer fully appropriate for, or relevant to, these stat-of-art systems. An attempt is made to develop an internally consistent audit and control Conceptual Framework summarizing and integrating the material developed in this research, which then leads into the analysis of the control and audit model.

• Water for future
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• v.29 no.5
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• pp.223-233
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• 1996

Daily streamflow model, DAWAST, considering the meteorologic and geographic characteristics of the Korean watersheds has been developed to simulate the daily streamflow with the input data of daily rainfall and pan evaporation. The model is the conceptual one with three sub-models which are optimization, generalization, and regionalization models. The conceptual model consists of three linear reservoirs representing the surface, unsaturated, and saturated soil zones and water balance analysis was carried out in each soil zones on a daily basis. Optimization model calibrates the parameters by optimization technique and is applicable to the watersheds where the daily streamflow data are available Generalization model predicts the parameters by regression equations considering the geographic, soil type, land use, and hydrogeologic characteristics of watershed and is appicable to ungaged medium or small watersheds. Regionalization model cites the parameters from the analysed ones considering river system, latitude and longitude, and is applicable to ungaged large watersheds.