• Journal of the Korea Computer Graphics Society
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• v.23 no.3
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• pp.105-113
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• 2017

This paper presents a novel on-line trajectory optimization framework based on automatic time warping, which performs the time warping of a reference motion while optimizing character motion control. Unlike existing physics-based character animation methods where sampling times for a reference motion are uniform or fixed during optimization in general, our method considers the change of sampling times on top of the dynamics of character motion in the same optimization, which allows the character to effectively respond to external pushes with optimal time warping. In order to do so, we formulate an optimal control problem which takes into account both the full-body dynamics and the change of sampling time for a reference motion, and present a model predictive control framework that produces an optimal control policy for character motion and sampling time by repeatedly solving the problem for a fixed-span time window while shifting it along the time axis. Our experimental results show the robustness of our framework to external perturbations and the effectiveness on rhythmic motion synthesis in accordance with a given piece of background music.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.272-279
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• 2013

The fermented puer tea leaves were high concentrated extracted with 50% ethanolic solution in this study. Also, evaluating the anti-oxidative activity and anti-aging effect of this extract, we expected to apply the cosmetic industry. The yield of fermented puer tea extract was 17.9%. The total polyphenol content was 37.5%, tannin content was 7.5%, polysaccharide was 17.9%, unknown compound was 22%, and water content was 8%. Anti-oxidative activity (in-vitro) of fermented puer tea extract by DPPH method was $33.7{\pm}1.8%$ in 30mg/mL, $39.4{\pm}2.2%$ in 50mg/mL respectively. Therefore, we could know that anti-oxidative activity of fermented puer tea extract was effect higher than tocopheryl acetate and greentea extract. The collagen synthesis activity (in-vitro) of fermented puer tea extract was increased with $102.9{\pm}9.9%$ in 1 mg/mL, $111.5{\pm}9.9%$ in 5 mg/mL, $122.7{\pm}12.2%$ in 10 mg/mL, $131.5{\pm}13.7%$ in 30 mg/mL (*p-value£0.05, n=3). Skin moisturizing activity of fermented puer tea extract after application 8 hours was increased 38.5% higher than control samples both tocopheryl acetate and greentea extract. Total moisturizing effect was increased about 32.7% compared to before treatment. Fermented puer tea extract of this study can be applied to the skin care cosmetics industry.

• Membrane Journal
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• v.33 no.6
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• pp.362-368
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• 2023

This research article explores the application of Polymer of Intrinsic Microporosity (PIM-1) as a cutting-edge material for CO₂ gas separation membranes in response to the escalating global concern over climate change and the imperative to reduce greenhouse gas emissions. The study delves into the synthesis, molecular weight control, and fabrication of PIM-1 membranes, providing comprehensive insights through various characterization techniques. The intrinsic microporosity of PIM-1, arising from its unique crosslinked and rigid structure, is harnessed for selective gas permeation, particularly of carbon dioxide. The article emphasizes the tunable chemical properties of PIM-1, allowing for customization and optimization of gas separation membranes. By controlling the molecular weight, higher molecular weight (H-PIM-1) membranes are demonstrated to exhibit superior CO₂ permeability and selectivity compared to lower molecular weight counterparts (L-PIM-1). The study's findings highlight the critical role of molecular weight in tailoring PIM-1 membrane properties, contributing to the advancement of next-generation membrane technologies for efficient and selective CO₂ capture-an essential step in addressing the pressing global challenge of climate change.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.542-549
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• 2023

Since the growing interest in surrogate modeling, there has been continuous research aimed at simulating nonlinear chemical processes using data-driven machine learning. However, the opaque nature of machine learning models, which limits their interpretability, poses a challenge for their practical application in industry. Therefore, this study aims to analyze chemical processes using Explainable Artificial Intelligence (XAI), a concept that improves interpretability while ensuring model accuracy. While conventional sensitivity analysis of chemical processes has been limited to calculating and ranking the sensitivity indices of variables, we propose a methodology that utilizes XAI to not only perform global and local sensitivity analysis, but also examine the interactions among variables to gain physical insights from the data. For the ammonia synthesis process, which is the target process of the case study, we set the temperature of the preheater leading to the first reactor and the split ratio of the cold shot to the three reactors as process variables. By integrating Matlab and Aspen Plus, we obtained data on ammonia production and the maximum temperatures of the three reactors while systematically varying the process variables. We then trained tree-based models and performed sensitivity analysis using the SHAP technique, one of the XAI methods, on the most accurate model. The global sensitivity analysis showed that the preheater temperature had the greatest effect, and the local sensitivity analysis provided insights for defining the ranges of process variables to improve productivity and prevent overheating. By constructing alternative models for chemical processes and using XAI for sensitivity analysis, this work contributes to providing both quantitative and qualitative feedback for process optimization.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.2
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• pp.86-96
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• 2006

Ecoclimap-1, a new complete surface parameter global database at a 1-km resolution, was previously presented. It is intended to be used to initialize the soil-vegetation- atmosphere transfer schemes in meteorological and climate models. Surface parameters in the Ecoclimap-1 database are provided in the form of a per-class value by an ecoclimatic base map from a simple merging of land cover and climate maps. The principal objective of this ecoclimatic map is to consider intra-class variability of life cycle that the usual land cover map cannot describe. Although the ecoclimatic map considering land cover and climate is used, the intra-class variability was still too high inside some classes. In this study, a new strategy is defined; the idea is to use the information contained in S10 NDVI SPOT/VEGETATION profiles to split a land cover into more homogeneous sub-classes. This utilizes an intra-class unsupervised sub-clustering methodology instead of simple merging. This study was performed to provide a new ecolimatic map over Northeast Asia in the framework of Ecoclimap-2 global database construction for surface parameters. We used the University of Maryland's 1km Global Land Cover Database (UMD) and a climate map to determine the initial number of clusters for intra-class sub-clustering. An unsupervised classification process using six years of NDVI profiles allows the discrimination of different behavior for each land cover class. We checked the spatial coherence of the classes and, if necessary, carried out an aggregation step of the clusters having a similar NDVI time series profile. From the mapping system, 29 ecosystems resulted for the study area. In terms of climate-related studies, this new ecosystem map may be useful as a base map to construct an Ecoclimap-2 database and to improve the surface climatology quality in the climate model.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.99.1-100
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• 2003

E. intermedium Blocontrol activity of a P. chlororaphis rhizobacteium O6, depends to the synthesis of extracellular secondary metabolites and exoenzymes, thought to antagonize the pathogenicity of a variety of phytopathogenic fungi. The production of secondary metabolites and exoenzymes in O6, depends essentially on the GacS-mediated signal transduction pathway, which activates largely unknown signal transduction pathway. To exploit the GacS-mediated signal transdcution pathway involved in activation of ph genes that are necessary for biosynthesis of phenazine from P. chlororaphis O6, we cloned and sequenced the phz operon, rpoS gene encoding stationary specific sigma factor, ppx gene encoding polyphosphatase, and lon gene encoding ion protease. Expression of each gene in wild type and GacS mutant were analyzed by RT-PCR. Transcripts from rpoS, phzI enconing acylhomoserine lactone (AHL) synthase, and ph structural genes in the GacS mutant were reduced in each of these growth phases compared to the wild type. The GacS or Lon mutant was found to be deficient in the production of phenzines, exoenzymes, and the acylhomoserine lactone. These mutants were not complemented by ph operon and addition of exogenous AHL. These results indicate that the GacS global regulatory systems controls phenazine production at multiple levels. Future research will focus to identifying the GacS-mediated regulatory cascade involving in production of phenazine in P. chlororaphis.

• Journal of Preventive Medicine and Public Health
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• v.46 no.2
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• pp.105-110
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• 2013

Objectives: The mass media play a crucial role in risk communication regarding climate change. The aim of this study was to investigate the trend in journalistic reports on climate change in the daily newspapers of Korea. Methods: We selected 9 daily newspapers in Korea, which according to the ABC Association, represented 77% of newspaper circulation, out of a total of 44 Korean daily newspapers. The collected articles were from 2009 to 2011. All of the articles were sorted into the following 8 categories: greenhouse gas, climate change conventions, sea level rise, Intergovernmental Panel on Climate Change synthesis reports, expected damage and effect, use of fossil fuels, global warming, and mitigation or adaptation. A chi-squared test was done on the articles, which were counted and classified into cause, effect, and measurement of climate change according to the newspaper's majority or minority ownership structure. Results: From the 9 selected newspapers, the number of articles on climate change by month was greatest in December 2009. Generally, the articles vague about climate change (lack of precise data, negative or skeptical tone, and improper use of terminology) were much more common than the articles presenting accurate knowledge. A statistical difference was found based on ownership structure: the majority-owned newspapers addressed the cause of climate change, while the minority-owned newspapers referred more to climate change measurement. Conclusions: Our investigation revealed that generally Korean daily newspapers did not deliver accurate information about climate change. The coverage of the newspapers showed significant differences according to the ownership structure.

• The Journal of the Korea Contents Association
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• v.18 no.4
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• pp.89-98
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• 2018

Due to the increasing global prevalence of dementia, such as Alzheimer disease, there is a growing public health concern about its prevention. The purpose of this study was to conduct a systematic review for a narrative synthesis and critical appraisal of current published research related to dementia prevention programs among Koreans. To conduct a systematic review, the data bases KoreaMed, Riss4u and 9 Nursing Journals were searched using the key words dementia prevention and cognitive function. Articles published between 2000~2014 and related to dementia prevention programs were reviewed. Two hundred-fifty references were searched but only 29 studies met our inclusion criteria to review. We found that dementia prevention programs focused on: exercise, 11 studies (37.9%); multi-therapy, 9 studies (31.0%); and cognitive enhancement activity, 4 studies(13.8%). The majority of studies (n=19, 65.5%) included adults over 65 while two studies targeted adults over 75. The current literature indicates that future research is needed to develop and provide appropriate and effective dementia prevention programs among Korean older adults.

• Journal of Powder Materials
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• v.22 no.3
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• pp.163-168
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• 2015

Ti alloys are extensively used in high-technology application because of their strength, oxidation resistance at high temperature. However, Ti alloys tend to be classified very difficult to cut material. In this paper, The powder synthesis, spark plasma sintering (SPS), bulk material properties such as electrical conductivity and thermal conductivity are systematically examined on $Ti_2AlN$ and $Ti_2AlC$ materials having most light-weight and oxidation resistance among the MAX phases. The bulk samples mainly consisted of $Ti_2AlN$ and $Ti_2AlC$ materials with density close to theoretical value were synthesized by a SPS method. Machining characteristics such as machining time, surface quality are analyzed with measurement of voltage and current waveform according to machining condition of micro-electrical discharge machining with micro-channel shape.

• Elastomers and Composites
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• v.52 no.2
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• pp.99-104
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• 2017

Due to the depletion of fossil oil and the increasing oil price, bio-plastic is currently topical. Bio-based plastics are synthesized from plant resources, unlike conventional petroleum-based counterparts. Therefore, the former minimizes global warming and reduces carbon dioxide emission. Fossil polycarbonate (PC)has good mechanical and optical properties, but its synthesis requires bisphenol-A and phosgene gas, which are toxic to humans. To address these problems, the fused deposition 3D printing process (hereafter, FDM) is studied using environmentally-friendly and high-strength bio-based PC. A comparisonof the environmental impact and tensile strength of fossil PC versus bio-based PC is presented herein, demonstrating that bio-based PC is more environmentally-friendly with higher tensile strength than fossil PC. The advantages of bio-based PC are applied in the FDM process for the fabrication of environmentally-friendly baby toys.