• Journal of Drive and Control
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• v.18 no.4
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• pp.35-42
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• 2021

A personal mobility withstanding function for the disabled and vulnerable groups with difficulties in mobility was developed and structural and dynamics analysis was conducted. Personal mobility devices are a very helpful means of transportation for the disabled and vulnerable groups. In addition, the standing function allows individuals to perform a difficult task in while seated and offers a medical advantage to the user. In this study, a personal mobility device was designed and developed to help vulnerable groups and disabled people overcome limited mobility, and communicate with the general people at eye level through standing functions. Through structural and dynamic analysis, the structural safety, optimal speed during rotation, and lateral acceleration of the personal mobility device was analyzed. The analysis results are expected to contribute to the improvement of the users' convenience and stability of personal mobility.

• Coupled systems mechanics
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• v.11 no.1
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• pp.43-54
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• 2022

In order to analyse the thermal performance of battery systems in electric vehicles complex simulation models with high computational cost are necessary. Using reduced order methods, real-time applicable model can be developed and used for on-board monitoring. In this work a data driven model of the cooling plate as part of the battery system is built and derived from a computational fluid dynamics (CFD) model. The aim of this paper is to create a meta model of the cooling plate that estimates the temperature at the boundary for different heat flow rates, mass flows and inlet temperatures of the cooling fluid. In order to do so, the cooling plate is simulated in a CFD software (ANSYS Fluent ®). A data driven model is built using the design of experiment (DOE) and various approximation methods in Optimus ®. The model can later be combined with a reduced model of the thermal battery system. The assumption and simplification introduced in this paper enable an accurate representation of the cooling plate with a real-time applicable model.

• Journal of Wellness
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• v.6 no.3
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• pp.13-21
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• 2011

The purpose of this study was to examine the potential predictors of leisure behavior intention using the theory of planned behavior(TPB). A convenience sample of 369 participants was obtained from university students in Korea and America. For the purposes of this study, potential predictors of leisure behavior intention were selected from the following categories: attitude, subject norm, perceived behavior control, group conformity and face saving. In order to better understand the dynamics of the TPB process that influenced leisure behavior intention, this study used structural equation modeling(SEM) to test the TPB model. According to the results, attitude, subject norm, and perceived behavior control influenced to leisure behavior intention of both Korean and American university students and face saving influenced to leisure behavior intention of Korean university students. However, group conformity did not influence to leisure behavior intention of either Korean and American university students. For future study, more specific and decomposed factors are recommended to understand leisure behavior intention in theoretical way.

• Journal of Astronomy and Space Sciences
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• v.41 no.1
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• pp.35-42
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• 2024

Sungrazing comets, known for their proximity to the Sun, are traditionally classified into broad groups like Kreutz, Marsden, Kracht, Meyer, and non-group comets. While existing methods successfully categorize these groups, finer distinctions within the Kreutz subgroup remain a challenge. In this study, we introduce an automated classification technique using the densitybased spatial clustering of applications with noise (DBSCAN) algorithm to categorize sungrazing comets. Our method extends traditional classifications by finely categorizing the Kreutz subgroup into four distinct subgroups based on a comprehensive range of orbital parameters, providing critical insights into the origins and dynamics of these comets. Corroborative analyses validate the accuracy and effectiveness of our method, offering a more efficient framework for understanding the categorization of sungrazing comets.

• Korean Journal of Ichthyology
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• v.27 no.3
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• pp.217-227
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• 2015

Reproductive biology and population dynamics of Luciogobius guttatus were investigated. Higher gonadosomatic index (GSI) was observed from March~May. The fecundity ranged form 241 eggs at 3.1~4.0 cm (SL) to 716 eggs at 5.1~5.7 cm (SL). The relationship between length (SL) and fecundity (F) was $F=11.242SL^{2.464}$ ($R^2=0.65$) and fecundity increased with length. We estimated the SL at 50% group maturity as 2.6 cm. The spawning period was March~May. The von Bertalanffy growth function (VBGF) estimates were: $L_{\infty}=63.00mm$ TL; $K=0.85yr^{-1}$. The structure of recruitment pattern obtained by the FiSAT II program indicated one normally distributed group. The growth performance index (${\phi}$) was calculated with 3.53. Natural mortality rate (M) was $1.00yr^{-1}$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1543-1549
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• 2012

This study focuses on the state space model and the design of a state observer for the slip dynamics between rolls in STS cold cluster mills. First, a mathematical model of the roll slip is given as a nonlinear differential equation. Then, by using a Taylor series expansion, it is linearized as a state space model. Next, by using Gopinath's algorithm, a minimal-order state observer based on the state space model is designed to estimate the angular speed of all idle rolls except for an actuated roll that is measureable. Finally, a computer simulation is used to validate that the proposed state space model very well describes slip dynamics between, and moreover, the state observer very well estimates the angular speed of the idle roll.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.52-61
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• 2006

The aim of this study was to analyze the seasonal patterns of zooplankton community dynamics in the lower Nakdong River (Mulgum, RK; river kilometer; 27 km from the estuarine barrage), with a Self-Organizing Map (SOM) based on weekly sampled data collected over ten years(1994 ${\sim}$ 2003). It is well known that zooplankton groups had important role in the food web of freshwater ecosystems, however, less attention has been paid to this group compared with other community constituents. A non-linear patterning algorithm of the SOM was applied to discover the relationship among river environments and zooplankton community dynamics. Limnological variables (water temperature, dissolved oxygen, pH , Secchi transparency, turbidity, chlorophyll a, discharge, etc.) were taken into account to implement patterning seasonal changes of zooplankton community structures (consisting of rotifers, cladocerans and copepods). The trained SOM model allocated zooplankton on the map plane with limnological parameters. Three zooplankton groups had high similarities to one another in their changing seasonal patterns, Among the limnological variables, water temporature was highly related to the zooplankton community dynamics (especially for cladocerans). The SOM model illustrated the suppression of zooplankton due to the increased river discharge, particularly in summer. Chlorophyll a concentrations were separated from zooplankton data set on the map plane, which would intimate the herbivorous activity of dominant grazers. This study introduces the zooplankton dynamics associated with limnological parameters using a nonlinear method, and the information will be useful for managing the river ecosystem, with respect to the food web interactions.

• Cartoon and Animation Studies
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• s.40
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• pp.109-137
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• 2015

As Digital technology developed, drawing animation, using traditional production method which expresses many feelings with drawn lines loses the youth group, the primary audience, to the realism of the digital cinema. Drawing animation, which drew attention of the youth by the spectacles in the film such as hectic pace, dynamics and punch, declined for a while. However, it has been developed a way to express pace and dynamics of its own by establishing an effective directing method, which combines digital technology as it is needed. This study has a purpose to investigate what causes the dynamics and feeling of fast movement of the character in Japanese limited animation. Though some action-animated films that heroes with supernatural powers take the leading role that feeling of velocity and dynamics are emphasized we compare the directing method before and after the introduction of the digital technology. This research reaches the conclusion by factoring each Bergson and McLuhan's discussion to the intervention of indexical signs and the audience's participation according to skipping technique. This study has a significance of researching the element of drawing animation that maximizes the expansion of the senses by defying the limitation of the law of physics through its unique way of directing together with growth of the hero films, which will continue.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.1
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• pp.65-77
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• 2009

This study conducted a comparative analysis between Koreans and foreigners on how they feel of the 'Oreum' so that the data could be used to conserve and utilize 'Oreum' as a brand of Jeju, which is one of the natural and original sceneries of the island along with Halla Mountain. Four aerial photo slides were selected to be assessed among 18 overlooked views of 'Oreums' through quasi-preliminary and preliminary surveys. The assessment group was divided into native and foreigner groups. Image and preference were measured based on 7 step categorization on 26 adjectives, and factor analysis was implemented. The selected factors from factor analysis reflected that calmness was recognized as common image identification variable to natives and foreigners. However, foreigners choose 'dynamics', 'peculiarity' and 'grandeur' in order to explain the image while Koreans selected words in the order of 'attractiveness', 'grandeur', 'dynamics' and 'peculiarity'. This means Koreans identify the image of 'Oreum' as absolute beauty while foreigners see the dynamics and relative peculiarity as its attractive point. As a result of factor score, preference and multiple regression analysis, Koreans selected 'calmness', 'attractiveness' and 'dynamics' as important variables to explain preference. On the other hand, foreigners choose 'dynamics' and 'calmness' as well as 'evenness', 'peculiarity' and 'simplicity'. This represents that foreigners are highly influenced by the structural peculiarity and simplicity on the image preference.

• Journal of the Mineralogical Society of Korea
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• v.29 no.4
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• pp.209-220
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• 2016

Clay minerals are a major player to determine geochemical cycles of trace metals and carbon in the critical zone which covers the atmosphere down to groundwater aquifers. Molecular dynamics (MD) simulations can examine the Earth materials at an atomic level and, therefore, provide detailed fundamental-level insights related to physicochemical properties of clay minerals. In the current study, we have applied classical MD simulations with clayFF force field to dioctahedral clay minerals (i.e., gibbsite, kaolinite, and pyrophyllite) to analyze and compare structural parameters (lattice parameter, atomic pair distance) with experiments. We further calculated vibrational power spectra for the hydroxyls of the minerals by using the MD simulations results. The MD simulations predicted lattice parameters and interatomic distances respectively deviated less than 0.1~3.7% and 5% from the experimental results. The stretching vibrational wavenumber of the hydroxyl groups were calculated $200-300cm^{-1}$ higher than experiment. However, the trends in the frequencies among different surface hydroxyl groups of each mineral was consistent with experimental results. The angle formed by the surface hydroxyl group with the (001) plane and hydrogen bond distances of the surface hydroxyls were consistent with experimental result trends. The inner hydroxyls, however, showed results somewhat deviated from reported data in the literature. These results indicate that molecular dynamics simulations with clayFF can be a useful method in elucidating the roles of surface hydroxyl groups in the adsorption of metal ions to clay minerals.