• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.1
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• pp.30-37
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• 2011

This paper presents a circuit configuration of multilevel inverter to synthesize a large number of output voltage levels by connecting a full-bridge inverter to a 5-level inverter in series. We analyze the characteristics by computer-aided simulations and experiments when it has input voltage sources which have the same and the power of three in the amplitude. In addition, it is compared with the conventional transformer based multilevel inverter.

• Communications for Statistical Applications and Methods
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• v.27 no.2
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• pp.211-224
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• 2020

Sensitivity and specificity are popular measures described by the receiver operating characteristic (ROC) curve. There are also two other measures such as the positive predictive value (PPV) and negative predictive value (NPV); however, the PPV and NPV cannot be represented by the ROC curve. Based on the total operating characteristic (TOC) curve suggested by Pontius and Si (International Journal of Geographical Information Science, 97, 570-583, 2014), explanatory methods are proposed to geometrically describe the PPV and NPV by the TOC curve. It is found that the PPV can be regarded as the slope of the right-angled triangle connecting the origin to a certain point on the TOC curve, while 1 - NPV can be represented as the slope of the right-angled triangle connecting a certain point to the top right corner of the TOC curve. When the neutral zone exists, the PPV and 1-NPV can be described as the slopes of two other right-angled triangles of the TOC curve. Therefore, both the PPV and NPV can be estimated using the TOC curve, whether or not the neutral zone is present.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.91-99
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• 2004

An unstructured tetrahedral mesh generation algorithm has been presented. In order to construct better meshes in interior region by using an advancing front technique, a connecting operator and a local finishing operator II have been developed in addition to the existing operators. Before applying digging operators that generate new nodes inside of a meshing region, a connecting operator is employed that uses existing nodes which satisfy certain conditions for producing well-conditioned elements. The local finishing operator II is introduced to terminate the meshing process more flexibly on remaining subregions. With these new operators, tetrahedral meshing process becomes more robust and good quality of meshes are constructed.

• Journal of information and communication convergence engineering
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• v.17 no.2
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• pp.142-148
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• 2019

Relatively few countries provide separate bicycle lanes for cyclists. Hence, tools for suggesting cycling routes are essential for a safe and pleasant cycling experience. This study aims to develop a mobile application to build cycling routes based on user preferences, specifically location, search radius, ride distance, and number of optimal routes. Our application calls the Strava API to retrieve Strava cycling segments crowdsourced from the cycling community. Then, it creates a graph consisting of the start and end points of these segments. Beginning from a user-specified location, the depth-first search algorithm (DFS) is applied to find routes that conform to the user's preferences. Next, a set of optimal routes is obtained by computing a trade-off ratio for every discovered route. This ratio is calculated from the lengths of all segments and the lengths of all connecting paths. The connected routes can be displayed on a map on an Android device or exported as a GPX file to a bike computer. Future work must be performed to improve the design of the user interface and user experience.

• Genomics & Informatics
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• v.17 no.2
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• pp.13.1-13.3
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• 2019

The usage of controlled biomedical vocabularies is the cornerstone that enables seamless interoperability when using a common data model across multiple data sites. The Observational Health Data Science and Informatics (OHDSI) initiative combines over 100 controlled vocabularies into its own. However, the OHDSI vocabulary is limited in the sense that it combines multiple terminologies and does not provide a direct way to link them outside of their own self-contained scope. This issue makes the tasks of enriching feature sets by using external resources extremely difficult. In order to address these shortcomings, we have created a linked data version of the OHDSI vocabulary, connecting it with already established linked resources like bioportal, bio2rdf, etc. with the ultimate purpose of enabling the interoperability of resources previously foreign to the OHDSI universe.

• Journal of the Korean Institute of Navigation
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• v.17 no.3
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• pp.15-47
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• 1993

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.245-245
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• 2003

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2002.05a
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• pp.127-132
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• 2002

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.184-187
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• 1986

A time-division-mutiplexed switching system is implemented for connecting various computers and terminals in the laboratory environment.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2004.11a
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• pp.125-130
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• 2004