• Fashion & Textile Research Journal
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• v.23 no.6
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• pp.799-809
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• 2021

This study aimed to grasp the perceptions and trends in fashion platforms and fashion smart factories using big data analysis. As a research method, big data analysis, fashion platform, and smart factory were identified through literature and prior studies, and text mining analysis and network analysis were performed after collecting text from the web environment between April 2019 and April 2021. After data purification with Textom, the words of fashion platform (1,0591 pieces) and fashion smart factory (9750 pieces) were used for analysis. Key words were derived, the frequency of appearance was calculated, and the results were visualized in word cloud and N-gram. The top 70 words by frequency of appearance were used to generate a matrix, structural equivalence analysis was performed, and the results were displayed using network visualization and dendrograms. The collected data revealed that smart factory had high social issues, but consumer interest and academic research were insufficient, and the amount and frequency of related words on the fashion platform were both high. As a result of structural equalization analysis, it was found that fashion platforms with strong connectivity between clusters are creating new competitiveness with service platforms that add sharing, manufacturing, and curation functions, and fashion smart factories can expect future value to grow together, according to digital technology innovation and platforms. This study can serve as a foundation for future research topics related to fashion platforms and smart factories.

• Journal of Electrochemical Science and Technology
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• v.14 no.1
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• pp.96-104
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• 2023

Synergistically increased oxygen evolution reaction (OER) of manganese oxide (MnO₂) catalyst is introduced with surface-modified halloysite nanotube (Fe₃O₄-HNTs) structure. The flake shaped MnO₂ catalyst is attached on the nanotube template (Fe₃O₄-HNTs) by series of wet chemical and hydrothermal method. The strong interaction between MnO₂ and Fe₃O₄-HNTs maximized active surface area and inter-connectivity for festinate charge transfer reaction for OER. The synergistical effect between Fe₃O₄ layer and MnO₂ catalyst enhance the Mn³⁺/Mn⁴⁺ ratio by partial replacement of Mn ions with Fe. The relatively increased Mn³⁺/Mn⁴⁺ ratio on MnO₂@FHNTs induced 𝜎^* orbital (e_g) occupation close to single electron, improving the OER performances. The MnO₂@FHNTs catalyst exhibited the reduced overpotential of 0.42 V (E vs. RHE) at 10 mA/cm² and Tafel slope of (99 mV/dec), compared with that of MnO₂ with unmodified HNTs (0.65 V, 219 mV/dec) and pristine MnO₂ (0.53 V, 205 mV/dec). The present study provides simple and innovative method to fabricate nano fiberized OER catalyst for a broad application of energy conversion and storage systems.

• Journal of Biomedical Engineering Research
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• v.39 no.3
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• pp.124-133
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• 2018

We tried to investigate the changes in cortical activities according to emotional valence states during watching video clips. We examined the neural basis of two emotional states (positive and negative) using spectral power analysis and brain functional connectivity analysis of cortical current density time-series reconstructed from high-density electroencephalograms (EEGs). Fifteen healthy participants viewed a series of thirty-two 2 min emotional video clips. Sixty-four channel EEGs were recorded. Distributed cortical sources were reconstructed using weighted minimum norm estimation. The temporal and spatial characteristics of spectral source powers showing significant differences between positive and negative emotion were examined. Also, correlations between gamma-band activities and affective valence ratings were determined. We observed the changes of cortical current density time-series according to emotional states modulated by video clip. Gamma-band activities showed significant difference between emotional states for thirty seconds at the middle and the latter half of the video clip, mainly in prefrontal area. It was also significantly anti-correlated with the self-ratings of emotional valence. In addition, the gamma-band activities in frontal and temporal areas were strongly phase-synchronized, more strongly for negative emotional states. Cortical activities in frontal and temporal areas showed high spectral power and inter-regional phase synchronization in gamma-band during negative emotional states. It is inferred that the higher amygdala activation induced by negative stimuli resulted in strong emotional effects and caused strong local and global synchronization of neural activities in gamma-band in frontal and temporal areas.

• Journal of KIISE:Information Networking
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• v.34 no.3
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• pp.226-238
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• 2007

In this paper, we present a novel fully distributed topology control protocol that can construct the multiple-ring topology of Minimal Connected Dominating Set (MCDS) as the transport backbone for mobile ad hoc networks. It makes a topology from the minimal nodes that are chosen from all the nodes, and the constructed topology is comprised of the minimal physical links while preserving connectivity. This topology reduces the interference. The all nodes work as the nodes of the distributed parallel Boltzmann machine, of which the objective function is consisted of two Boltzmann factors: the link degree and the connection domination degree. To define these Boltzmann factors, we extend the Connected Dominating Set into a fuzzy set, and also define the fuzzy set of nodes by which the multiple-ring topology can be constructed. To construct the transport backbone of the mobile ad hoc network, the proposed protocol chooses the nodes that are the strong members of these two fuzzy sets as the clusterheads. We also ran simulations to provide the quantitative comparison against the related works in terms of the packet loss rate and the energy consumption rate. As a result, we show that the network that is constructed by the proposed protocol has far better than the other ones with respect to the packet loss rate and the energy consumption rate.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.10-24
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• 2013

The state-of-arts of multiscale simulation (MSS) in science and engineering is briefly presented and MSS for process development (PD-MSS) is proposed to effectively apply the MSS to the process development. The four-level PD-MSS is composed of PLS (process-level simulation), FLS (fluid-level simulation), mFLS (microfluid-level simulation) and MLS (molecular-level simulation). Characteristics and methods of each level, as well as connectivity between the four levels are described. For example in PD-MSS, absorption column, fluidized-bed reactor, and adsorption process are introduced. For successful MSS, it is necessary to understand the multiscale nature in chemical engineering problems, to develop models representing physical phenomena at each scale and between scales, to develop softwares implementing mathematical models on computer, and to have strong computing facilities. MSS should be performed within acceptable accuracy of simulation results, available computation capacity, and reasonable efficiency of calculation. Macroscopic and microscopic scale simulations have been developed relatively well but mesoscale simulation shows a bottleneck in MSS. Therefore, advances on mesoscale models and simulation tools are required to accurately and reliably predict physical phenomena. PD-MSS will find its way into a sustainable technology being able to shorten the duration and to reduce the cost for process development.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.127-142
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• 2024

This study aimed to understand the interrelationships between tree species in plant communities through Plant Social Network (PSN) analysis using a large amount of vegetation data surveyed in an island area belonging to a warm-temperate boreal forest. The Machilus thunbergii, Castanopsis sieboldii, and Ligustrum japonicum, which belong to the canopy layer, Pittosporum tobira and Ardisia japonica, which belong to the shrub layer and Trachelospermum asiaticum and Stauntonia hexaphylla, which belong to the vines, appearing in evergreen broad-leaved climax forest community, showed strong positive association(+) with each other. These tree species had a negative association or no friendly relationship with deciduous broad-leaved species due to the large difference in location environments. Divided into 4 group modularizations in the PSN sociogram, evergreen broad-leaved tree species in Group I and deciduous broad-leaved tree species in Group II showed high centrality and connectivity. It was analyzed that the arrangement of tree species (nodes) and the degree of connection (grouping) of the sociogram can indirectly estimate environmental factors and characteristics of plant communities like DCA. Tree species with high centrality and influence in the PSN included T. asiaticum, Eurya japonica, Lindera obtusiloba, and Styrax japonicus. These tree species are common with a wide range of ecological niches and appear to have the characteristics and survival strategies of opportunistic species that commonly appear in forest gaps and damaged areas. They will play a major role in inter-species interactions and structural and functional changes in plant communities. In the future, long-term research and in-depth discussions are needed to determine how these species actually influence plant community changes through interactions

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.2
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• pp.71-86
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• 2021

This study was conducted to find information on the university's image from words related to 'Korea National College of Agriculture and Fisheries (KNCAF)' in Naver News. For this purpose, word frequency analysis, TF-IDF evaluation and semantic network analysis were performed using web crawling technology. In word frequency analysis, 'agriculture', 'education', 'support', 'farmer', 'youth', 'university', 'business', 'rural', 'CEO' were important words. In the TF-IDF evaluation, the key words were 'farmer', 'dron', 'agricultural and livestock food department', 'Jeonbuk', 'young farmer', 'agriculture', 'Chonju', 'university', 'device', 'spreading'. In the semantic network analysis, the Bigrams showed high correlations in the order of 'youth' - 'farmer', 'digital' - 'agriculture', 'farming' - 'settlement', 'agriculture' - 'rural', 'digital' - 'turnover'. As a result of evaluating the importance of keywords as five central index, 'agriculture' ranked first. And the keywords in the second place of the centrality index were 'farmers' (Cc, Cb), 'education' (Cd, Cp) and 'future' (Ce). The sperman's rank correlation coefficient by centrality index showed the most similar rank between Degree centrality and Pagerank centrality. The KNCAF articles of Naver News were used as important words such as 'agriculture', 'education', 'support', 'farmer', 'youth' in terms of word frequency. However, in the evaluation including document frequency, the words such as 'farmer', 'dron', 'Ministry of Agriculture, Food and Rural Affairs', 'Jeonbuk', and 'young farmers' were found to be key words. The centrality analysis considering the network connectivity between words was suitable for evaluation by Cd and Cp. And the words with strong centrality were 'agriculture', 'education', 'future', 'farmer', 'digital', 'support', 'utilization'.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.3
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• pp.153-165
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• 2023

The purpose of this study is to propose effective scenarios for green areas in apartment complexes that can improve the connection between green spaces considering wind flow, thermal comfort, and mitigation of the urban heat island effect. The study site was an apartment complex in Godeok-dong, Gangdong-gu, Seoul, Korea. The site selection was based on comparing temperatures and discomfort index data collected from June to August 2020. Initially, the thermal and wind environment of the current site was analyzed. Based on the findings, three scenarios were proposed, taking into account both green patches and corridor elements: Scenario 1 (green patch), Scenario 2 (green corridor), and Scenario 3 (green patch & corridor). Subsequently, each scenario's wind speed, wind flow, and thermal comfort were analyzed using ENVI-met to compare their effectiveness in mitigating the urban heat island effect. The study results demonstrated that green patches contributed to increased wind speed and improved wind flow, leading to a reduction of 31..20% in the predicted mean vote (PMV) and 68.59% in the predicted percentage of dissatisfied (PET). On the other hand, green corridors facilitated the connection of wind paths and further increased wind speed compared to green patches. They proved to be more effective than green patches in mitigating the urban heat island, resulting in a reduction of 92.47% in PMV and 90.14% in PET. The combination of green patches and green corridors demonstrated the greatest increase in wind speed and strong connectivity within the apartment complex, resulting in a reduction of 95.75% in PMV and 95.35% in PET. However, patches in narrow areas were found to be more effective in improving thermal comfort than green corridors. Therefore, to effectively mitigate the urban heat island effect, enhancing green areas by incorporating green corridors in conjunction with green patches is recommended. This study can serve as fundamental data for planning green areas to mitigate future urban heat island effects in apartment complexes. Additionally, it can be considered a method to improve urban resilience in response to the challenges posed by the urban heat island effect.