• Journal of Power Electronics
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• v.19 no.2
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• pp.519-528
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• 2019

The unified power quality conditioner (UPQC) is an effective custom power device that is used at the point of common coupling to protect loads from voltage and current-related PQ issues. Currently, most researchers have studied series unit and parallel unit models and an idealized transformer model. However, the interactions of the series and parallel converters in AC-link are difficult to analyze. This study utilizes an equivalent transformer model to accomplish an electric connection of series and parallel converters in the AC-link and to establishes a precise unified mathematical model of the UPQC. The strong coupling interactions of series and parallel units are analyzed, and they show a remarkable dependence on the excitation impedance of transformers. Afterward, a feed-forward decoupling method based on a unified model that contains the uncertainty components of the load impedance is applied. Thus, this study presents an adaptive method to estimate load impedance. Furthermore, simulation and experimental results verify the accuracy of the proposed modeling and decoupling algorithm.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.1089-1100
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• 2018

In this paper, we analyze the feasibility of establishing a precise sensor model for high-resolution satellite imagery using unified control points. For this purpose, we integrated unified control points and the aerial orthoimages from the national land information map (http://map.ngii.go.kr/ms/map/NlipMap.do) operated by the National Geographic Information Institute (NGII). Then, we collected the image coordinates corresponding to the unified control point's location in the satellite image. The unified control points were used as observation data for establishing a precise sensor model. For the experiment, we compared the results of precise sensor modeling using GNSS survey data and those using unified control points. Our experimental results showed that it is possible to establish a precise sensor model with around 2 m accuracy when using unified control points.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.136-138
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• 2003

UML cannot meet all the requirements offered in different software system for diverse application domain. GNSS (Global Navigation Satellite System) application domain is an especial environment that requires precise measurement and precision calculation of real-world geographical entities with the help of GPS (Global Position System) in both temporal and spatial factor. Therefore in the paper new extended iconic stereotypes for better modeling GNSS application in the UML Diagram are proposed, and the implementation of a program called StereotypeCreator, which is able to create iconic stereotypes used in one of the most popular visual modeling tools for software development, Rational Rose, will be also proposed.

• Journal of KIISE:Software and Applications
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• v.32 no.6
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• pp.473-485
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• 2005

UML activity diagram is useful to model business process and workflow by reason of its suitability to present dynamic aspect of system. However it Is difficult to present precise semantics which is taken as important in workflow system with the guide provided by OMG to the UML activity diagram. This paper suggests workfolw system modelling methodology by applying ASM semantics to the activity diagram after extending its semantics to correspond to workflow system characteristics. Through the exact definition to formal semactics based on ASM it is possible to effectively model workflow.