• Korean Journal of Remote Sensing
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• v.24 no.1
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• pp.65-78
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• 2008

This study compares the relative accuracy and consistency of four split-window land surface temperature (LST) algorithms (Becker and Li, Kerr et ai., Price, Ulivieri et al.) using 24 sets of Terra (Aqua)/Moderate Resolution Imaging Spectroradiometer (MODIS) data, observed ground grass temperature and air temperature over South Korea. The effective spectral emissivities of two thermal infrared bands have been retrieved by vegetation coverage method using the normalized difference vegetation index. The intercomparison results among the four LST algorithms show that the three algorithms (Becker-Li, Price, and Ulivieri et al.) show very similar performances. The LST estimated by the Becker and Li's algorithm is the highest, whereas that by the Kerr et al.'s algorithm is the lowest without regard to the geographic locations and seasons. The performance of four LST algorithms is significantly better during cold season (night) than warm season (day). And the LST derived from Terra/MODIS is closer to the observed LST than that of Aqua/MODIS. In general, the performances of Becker-Li and Ulivieri et al algorithms are systematically better than the others without regard to the day/night, seasons, and satellites. And the root mean square error and bias of Ulivieri et al. algorithm are consistently less than that of Becker-Li for the four seasons.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.25 no.4
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• pp.296-311
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• 2021

Topological Data Analysis (TDA), a relatively new field of data analysis, has proved very useful in a variety of applications. The main persistence tool from TDA is persistent homology in which data structure is examined at many scales. Representations of persistent homology include persistence barcodes and persistence diagrams, both of which are not straightforward to reconcile with traditional machine learning algorithms as they are sets of intervals or multisets. The problem of faithfully representing barcodes and persistent diagrams has been pursued along two main avenues: kernel methods and vectorizations. One vectorization is the Betti sequence, or Betti curve, derived from the persistence barcode. While the Betti sequence has been used in classification problems in various applications, to our knowledge, the stability of the sequence has never before been discussed. In this paper we show that the Betti sequence is unstable under the 1-Wasserstein metric with regards to small perturbations in the barcode from which it is calculated. In addition, we propose a novel stabilized version of the Betti sequence based on the Gaussian smoothing seen in the Stable Persistence Bag of Words for persistent homology. We then introduce the normalized cumulative Betti sequence and provide numerical examples that support the main statement of the paper.

• International Journal of Contents
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• v.17 no.4
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• pp.101-118
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• 2021

The prevalence of We-Media short videos has attracted emerging independent fashion designers (EIFD), a new force in the fashion industry directing their brand promotion to We-Media for amassing online followers. However, compared to famous content generators, EIFDs' creative, design-based visual appeal has not provided them with the significant edge. The former's success is admittedly supported by the platform backstage algorithm. Yet, the content is the cornerstone for building relationship between the sender and the reception. The authentic perception of the content is one of the basic appeals for which the audience chooses to follow the source. Therefore, with the EIFD short video as the research content, this study is established from the audience's perspective to understand the different dimensions of their authentic perceptions of EIFDs short video. The study was conducted mainly in the form of the Q method. The collection of 52 Q samples were realized through the Focus Group Interview and literature review on multidimensional authenticity. Thirty-six subjects participated in the sorting of the Q-sets. Finally, four dimensions of audience authenticity perceptions of EIFDs were derived: 'ingenuity', 'relevant', 'transparent', and 'experiential'. The corresponding short video content design strategies are suggested for effective communication of EIFDs and their personal brands.

• Geomechanics and Engineering
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• v.17 no.6
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• pp.583-595
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• 2019

In this paper, a comprehensive investigation of the dynamic response of a long-bridge subjected to spatially varying earthquake ground motions (SVEGM) is performed based on a proposed analytical model which includes the effect of soil-structure interaction (SSI). The spatial variability of ground motions is simulated by the powerful record generator, SIMQKE II. Modeling of the SSI in the system is simplified by replacing the pile foundations and soil with sets of independent equivalent linear springs and dashpots along the pile groups. One of the most fundamental objectives of this study is to examine how well the proposed model simulates the dynamic response of a bridge system. For this purpose, the baseline data required for the evaluation process is derived from analyzing a 3D numerical model of the bridge system which is validated in this paper. To emphasize the importance of the SVEGM and SSI, bridge responses are also determined for the uniform ground motion and fixed base cases. This study proposing a compatible analytical model concerns the relative importance of the SSI and SVEGM and shows that these effects cannot be neglected in the seismic analysis of long-bridges.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.3
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• pp.271-279
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• 2021

Ultrasound-assisted extraction (UAE) conditions, including extraction time, extraction temperature, and ethanol concentration, were optimized to increase the total flavonoid content (TFC), tyrosinase inhibitory activity (TIA), and collagenase inhibitory activity (CIA) of Spirulina platensis through central composite design (CCD). For the optimization of the three dependent variables, a quadratic regression model was derived from 17 experimental sets for the simultaneous maximization of TFC, TIA, and CIA. The predicted optimal UAE conditions were 44.0 min of extraction time, 82.8℃ of extraction temperature, and 96.0% of ethanol concentration. Under these conditions, 0.93 mg QE/g DM of TFC, 81.9% of CIA, and 92.1% of TIA were predicted. The CCD-based UAE optimization enabled an increase in TFC, CIA, and TIA, thereby confirming that the S. platensis extract can be used in the development of a cosmetic material with skin whitening and anti-wrinkle effects.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.481-486
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• 2021

Machine learning algorithms adopt criterion function as a key component to measure the quality of their model derived from data. Cluster analysis also uses this function to rate the clustering result. All the criterion functions have in general certain types of favoritism in producing high quality clusters. These clusters are then described by attributes and their values. Category utility and partition utility play an important role in cluster analysis. These are fully analyzed in this research particularly in terms of how they are related to the favoritism in the final results. In this research, several data sets are selected and analyzed to show how different results are induced from these criterion functions.

• Journal of Korean Public Health Nursing
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• v.36 no.2
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• pp.196-211
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• 2022

Purpose: This is a phenomenological study to improve the quality of nursing and understand its essence by comprehensively analyzing job experience of nursing managers in small and medium. Methods: This study focused on deriving the common empirical attributes of all the study participants, rather than their individual attributes. Data on the job experiences of nine nurse managers in small and medium-sized hospitals were collected and analyzed using Colaizzi's phenomenological method. Result: The job experiences of nurse managers in small and medium hospitals were classified after analysis into 14 theme cluster sets and 34 themes in five categories. The categories derived were 'A feeling of pressure as if taking responsibility for the entire hospital', 'Taking on the difficulties of hiring a nurse alone.' 'Difficulty in mediating conflicts within the organization', 'Struggling to endure', 'To take root in the field with a sense of ownership'. Conclusion: This study is meaningful in helping nursing managers in small and medium hospitals perform their duties more efficiently and stably by understanding their job experience.

• Korean Journal of Pharmacognosy
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• v.53 no.3
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• pp.119-124
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• 2022

Vaginal microbiome deeply influences vaginal health via production of messenger molecules. The healthy vaginal pH ranges between 3.5 and 4.5. However, dysbiosis of vaginal microbiome increases the pH level, leading to the incidence of vaginitis. The commensal vaginal bacterium Dermabacter vaginalis-which was isolated from the vaginal fluid of a Korean female-was incubated in acidic and neutral pH to simulate healthy and vaginitis conditions, respectively. The chemical profiles of the two different cultures were compared using HPLC. The compound showing distinctive difference between the two sets of data was presumed to be a chemical messenger, which was identified as cyclo(L-pro-L-met) by analysis of NMR, MS, and specific rotation data. Synthesis was achieved in three steps (overall yield 15%), enabling structure confirmation and antimicrobial evaluation against vaginal pathogens. Cyclo(L-pro-L-met) showed antifungal activity against Candida albicans, a major cause of vulvovaginal candidiasis.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.530-545
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• 2023

As an alternative to conventional management options for a lot of concrete waste from decommissioning of nuclear power plants, a set of scenarios for controlled recycling of decommissioning concrete waste as engineered barriers of a radioactive waste repository was proposed, and a comprehensive safety assessment model and framework covering both pre-and post-closure phases was newly developed. The new methodology was applied to a reference vault-type repository, and the ratios of derived concentration limits to unconditional clearance levels of eighteen radionuclides for controlled recycling were provided for three sets of dose criteria (0.01, 1, and 20 mSv/y for the pre-closure and 0.01 mSv/y for the post-closure phases). It turns out that decommissioning concrete waste whose concentration is much higher than the unconditional clearance level can be recycled even when the dose criterion 0.01 mSv/y is applied. Moreover, a case study on ABWR bio-shield shows that the fraction of recyclable concrete waste increases significantly by increasing the dose criterion for the radiation worker in the pre-closure phase or the duration of storage prior to recycling. The results of this study are expected to contribute to demonstrating the feasibility of controlled recycling of a lot of decommissioning concrete waste within nuclear sectors.

• Structural Engineering and Mechanics
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• v.86 no.4
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• pp.519-533
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• 2023

This work focuses on the dynamic analysis of thermal barrier coated straight and curved turbine blades modelled as functionally graded sandwich panel under thermal environment. The pre- twisted straight/curved blade model is considered to be fixed to the hub and, the complete assembly of the hub and blade are assumed to be rotating. The functionally graded sandwich composite blade is comprised of functionally graded face-sheet material and metal alloy core. The constituents' material properties are assumed to be temperature-dependent, however, the overall properties are evaluated using Voigt's micromechanical scheme in conjunction with the modified power-law functions. The blade model kinematics is based on the equivalent single-layer shear deformation theory. The equations of motion are derived using the extended Hamilton's principle by including the effect of centrifugal forces, and further solved via 2D- isoparametric finite element approximations. The mesh refinement and validation tests are performed to illustrate the stability and accurateness of the present model. In addition, frequency characteristics of the pre-twisted rotating sandwich blades are computed under thermal environment at various sets of parametric conditions such as twist angles, thickness ratios, aspect ratios, layer thickness ratios, volume fractions, rotational velocity and blade curvatures which can be further useful for designing the blade type structures under turbine operating conditions.