• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.429-435
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• 2006

In this study multi-zone modeling program CONTAM 2.4 which is developed by NIST is used for modeling the air disinfection system which is consist of dilution, filtration, ultra violet germicidal irradiation (UVGI) for removing the indoor microorganism such as bacteria and fungus. Developed models those protect occupants against indoor microorganism generated in our daily life are enable to use for immune building simulation tool. Also, results indicate that those models are enable to compute the real situation that is almost impossible of carrying out experiment and identify the disinfection rate with highly reliance. Results also suggest that engineers will use these models as a design tool for the immune building system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.6
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• pp.279-286
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• 2001

A load modeling, micro method, is performed by component load modeling, load composition rate estimation and aggregation of component load model, etc. The load model obtained from this process must be applied to actual load bus to verify it and to get reliable load model. But it is difficult to apply every load bus due to al lot of load buses and complex experiment. This paper proposed the field test method in load bus to verify the load modeling. For appropriate field test, representative load buses are selected by the proposed algorithm considering the composition rate of user category in all load buses. The field tests were performed at selected load buses to obtain load characteristics of bus by time and seasonal without blackout. The results of measurement and analysis are presented in detail.

• School Mathematics
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• v.16 no.3
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• pp.409-444
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• 2014

There have been many discussions of teaching and learning mathematics through modeling activities in mathematics education research community. Although there has been some agreement regarding modeling activity as an alternative way to support mathematics teaching and learning, there is still no clear consensus on these issues. This paper reports a case study which aims to identify ways to design modeling tasks and instruction to foster meta-level learning, and investigate how modeling activities can facilitate meta-level learning. From the results of teaching experiment, this study examines the potential of modeling activities in mathematics teaching and learning.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.93-101
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• 2021

The purpose of this study is to analyze the adequacy of production capacity of the assembly process system of mobile bath vehicle's top box panel and process design through a simulation analysis. Towards this end, the layout of the facility designed with pre-verification job using a simulation modeling and an experiment, and facility, logistics process, and personnel input method were made into a simulation model, and the design system's adequacy was evaluated through an experiment. To produce 120 mobile bath vehicles annually, it was analyzed that 14 general workers and seven skilled workers were adequate through the experiment. It was also identified that three painting process lines carried out through outsourcing were adequate. Production lead time was 201.7 hours on average and it was 230 hours maximum. To meet customer delivery service level of 95% within the deadline when establishing a customer order and vehicle delivery plan, it was analyzed that more than 215 hours of lead time is needed minimum. If the process cycle time is reduced to 85% upon system stabilization and skillfulness improvement, it was analyzed that annual output of 147 vehicles can be achieved without additional production line expansion.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.610-614
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• 2004

Recently, an active-clamp, full-bridge boost converter has been actively studied for high-power applications such as power factor correction and battery discharger. However, DC and AC modeling for this converter has not conquered. In this paper, a DC and small-signal AC modeling for the active-clamp, full-bridge boost converter is described. Based on the operation principle, the ac part of the converter can be replaced by a do counterpart. Then, a conceptual equivalent circuit is derived by rearranging the switches. The equivalent circuit for this converter consists of CCM (Continuous conduction mode) boost and DCM (Discontinuous conduction mode) buck converter. The analyses for the equivalent CCM boost and DCM buck converter are done using the model of PWM switch. The theoretical modeling results are confirmed through experiment or SIMPLIS simulation.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_1
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• pp.513-519
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• 2022

In this paper, we describe performances of P-PD controllers in the quadrotor system with steady-state error compensation by adding a corrective term to the system input. A decentralized control system using P-PD controllers was successfully implemented on a quadrotor platform. We also presented the results of a mathematical modeling analysis for control the quadrotor and experimental results for each response performance according to the heading reference value in accordance with the mathematical modeling and P-PD controller design. A control experiment with the real system was implemented for the test platform, and the results were evaluated and compared.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.88-93
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• 2003

This paper presents an efficient dynamic modeling method for open cracked rotor-bearing systems. An equivalent bending spring model is introduced to represent the structural weakening effect in the presence of cracks. The proposed modeling method is validated through a series of simulations and experiments. First, the proposed method is rigorously compared with a commercial finite element code. Then, an experiment is performed to validate the proposed modeling method. Finally, a numerical example is introduced to demonstrate the possible application of the proposed method in the crack diagnosis fur rotor systems.

• Journal of Information Technology Applications and Management
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• v.18 no.4
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• pp.95-118
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• 2011

In developing information systems, conceptual modeling is among the most fundamental means. The importance attributed to conceptual modeling has not only given rise to a lot of modeling methods, but also to the "yet another modeling approach (YAMA)" syndrome and the "not another modeling approach (NAMA)" hysteria. Criticism of conceptual modeling methods usually targets their lacking of theoretical foundations. In response to such criticism, various approaches towards theoretical foundations of conceptual modeling have been proposed so far. One of the recent responses to the quest for theoretical foundations of conceptual modeling is the reference to the philosophical ontology. The currently most prominent of diverse approaches towards ontological foundations of conceptual modeling appears to be the Bunge-Wand-Weber (BWW) ontology. Recent approaches attempt to regard BWW ontology as another conceptual data model as well as a criterion for evaluating various conceptual models. However, unfortunately, relatively few researches have been made on interoperability between the Entity-Relationship (ER) model, which is the most dominant conceptual data model, and ontology based model. In this paper, we investigate the interoperability between ontology and the ER model. In detail we (i) reclassify components of ER model with respect to ontology concepts, (ii) identify some components that cannot be directly represented in ontology notation, and (iii) present alternative representations to the components to acquire ontologically clear ER diagrams. Additionally, we (iv) present a set of mapping rules for converting the ontologically clear ER diagram into the corresponding ontology. In a case study, we show the process of converting an ER diagram for a concise Project Management System (PMS) into the ontologically clear ER diagram and the corresponding ontology. We also describe an experiment that we undertook to test whether users understand the Ontologically-Clear ER diagram better.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.455-456
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• 2006

This paper presents an automatic pose-normalized 3D face data acquisition method using 2D and 3D information. We propose an automatic pose-normalized 3D face acquisition method that accomplishes 3D face modeling and 3D face pose-normalization at once. The proposed method uses 2D information with AAM (Active Appearance Model) and 3D information with 3D normal vector. The 3D face modeling system consists of 2 cameras and 1 projector. In order to verify proposed pose-normalized 3D modeling method, we made an experiment for 2.5D face recognition. The experimental result shows that proposed method is robust against pose variation.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.93.6-93
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• 2001

This paper describes the results on the fuzzy control in the modeling equipment of the height-level of water, in comparison with the results of PID control in the same system. By using two types of the fuzzy control, it is reported that the response rapidity, smoothness and complexity of the fuzzy control are superior to PID control by the experiment results.