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1,733 results on '"Kim, Hyun Kyung"'

153. Augmenting Qualitative Simulation with Global Filtering

Author

Kim, Hyun-Kyung

Abstract

Capturing correct changes both locally and globally is crucial to predicting the behavior of physical systems. However, due to the nature of qualitative simulation techniques, they cannot avoid losing some information which is useful for finding precise global behavior. This paper describes how global constraints are represented and m a nipulated in current simulation systems, using a model of an internal combustion engine. The basic idea of our approach is to automatically generate additional information for maintaining global constraints during simulation so that simulation techniques can filter global behaviors with the sufficient information. This is done by automatically introducing variables and controlling their values to guide correct transitions between the behaviors. W e express this idea within the framework of Qualitative Process (QP) theory. This technique has been implemented and integrated into an existing qualitative simulation program QPE.

Published
1992

156. Qualitative Reasoning about the Geometry of Fluid Flow

Author

Kim, Hyun-Kyung

Abstract

Understanding the interaction between dynamics and geometry is crucial to capturing commonsense physics. This paper presents a qualitative analysis of the direction of fluid flow. This analysis is dependent on qualitative descriptions of the surface geometry of rigid bodies in contact with the fluid and a pressure change in fluid. The key problem in designing an intelligent system to reason about fluid motion is how to partition the fluid at an appropriate level of representation. The basic idea of our approach is to incrementally generate the qualitatively different parts of fluid. We do this by dynamically analyzing the intereiction of geometry and pressure disturbance. Using this technique, we can derive all possible fluid flows.

Published
1990

170. Controlling Dendrite Formation for Long-Term Cyclability and Fast Li+Diffusion Kinetics in Solid-State Electrolyte Li7La3Zr2O12

Author

Sim, Jae-Won, Lee, Rae-Hyun, Kim, Hyun-Kyung, Lee, Jong Kyu, Yoon, Jung Rag, and Lee, Seung-Hwan

Abstract

Ga-doped Li7La3Zr2O12(Ga-LLZO) solid-state electrolyte is a promising material for advanced batteries due to its superior ionic conductivity and mechanical properties. However, Ga-LLZO is challenged by high grain boundary (GB) resistance and dendrite propagation. Therefore, in this study, we suggest the two-step sintering (TSS) method for controlling the microstructure, resulting in lower GB resistance and achieving superior dendrite resistance. To elucidate the cycling performance, a critical current density (CCD) test was performed on a Ga-LLZO sample fabricated with TSS. As a result, the Ga-LLZO sample fabricated with TSS demonstrates a superior CCD value of 0.32 mA cm–2as well as shows stable cycling at a current density of 0.2 mA cm–2. According to the impedance analysis, the sample fabricated with TSS demonstrates a significant increase in ionic conductivity compared to the sample fabricated with the conventional sintering (CS) method. This phenomenon implies that the enhanced sintering technique of TSS can reduce the GB resistance and dendrite formation by achieving the densification and tight GB. Extensive investigation into the dendrite formation mechanism has provided compelling evidence that dendrites are not solely composed of pure Li but rather consist of a compound containing both C and O elements. This finding significantly contributes to the understanding of the composition and nature of dendrites in Ga-LLZO, shedding light on their role in the acceleration of the phase decomposition process.

Published
2023
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191. sj-docx-1-cat-10.1177_10760296221123310 - Supplemental material for Assessment of Rotational Thromboelastometry and Thrombin Generation Assay to Identify Risk of High Blood Loss and Re-Operation After Cardiac Surgery

Author

Jeong, Dajeong, Kim, Seon Young, Gu, Ja-Yoon, and Kim, Hyun Kyung

Subjects
FOS: Clinical medicine, Cardiology, 111599 Pharmacology and Pharmaceutical Sciences not elsewhere classified
Abstract

Supplemental material, sj-docx-1-cat-10.1177_10760296221123310 for Assessment of Rotational Thromboelastometry and Thrombin Generation Assay to Identify Risk of High Blood Loss and Re-Operation After Cardiac Surgery by Dajeong Jeong, Seon Young Kim and Ja-Yoon Gu, Hyun Kyung Kim in Clinical and Applied Thrombosis/Hemostasis

Published
2022
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