• Journal of Soil and Groundwater Environment
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• v.25 no.1
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• pp.25-36
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• 2020

In a redox transition zone, geochemical reactions are facilitated by active bacteria that mediate reactions involving electrons, and arsenic (As) and iron (Fe) cycles are the major electron transfer reactions occurring at such a site. In this study, the effect of repetitive redox changes on soil bacterial community in As-contaminated soil was investigated. The results revealed that bacterial community changed actively in response to redox changes, and bacterial diversity gradually decreased as the cycle repeated. Proportion of strict aerobes and anaerobes decreased, while microaerophilic species such as Azospirillum oryzae group became the predominant species, accounting for 72.7% of the total counts after four weeks of incubation. Bacterial species capable of reducing Fe or As (e.g., Clostridium, Desulfitobacterium) belonging to diverse phylogenetic groups were detected. Indices representing richness (i.e., Chao 1) and phylogenetic diversity decreased from 1,868 and 1,926 to 848 and 1,121, respectively. Principle component analysis suggests that repetitive redox fluctuation, rather than oxic or anoxic status itself, is an important factor in determining the change of soil bacterial community, which in turn affects the cycling of As and Fe in redox transition zones.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1593-1604
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• 2016

Recently, bacterial quorum quenching (QQ) has been proven to have potential as an innovative approach for biofouling control in membrane bioreactors (MBRs) for advanced wastewater treatment. Although information regarding the microbial community is crucial for the development of QQ strategies, little information exists on the microbial ecology in QQ-MBRs. In this study, the microbial communities of biofilm were investigated in relation to the effect of QQ on anoxic/oxic MBRs. Two laboratory-scale MBRs were operated with and without QQ-beads (QQ-bacteria entrapped in beads). The transmembrane pressure increase in the QQ-MBRs was delayed by approximately 100-110% compared with conventional- and vacant-MBRs (beads without QQ-bacteria) at 45 kPa. In terms of the microbial community, QQ gradually favored the development of a diverse and even community. QQ had an effect on both the bacterial composition and change rate of the bacterial composition. Proteobacteria and Bacteroidetes were the most dominant phyla in the biofilm, and the average relative composition of Proteobacteria was low in the QQ-MBR. Thiothrix sp. was the dominant bacterium in the biofilm. The relative composition of Thiothrix sp. was low in the QQ-MBR. These findings provide useful information that can inform the development of a new QQ strategy.

• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1168-1177
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• 2018

The aim of this study was to investigate the microbial community of three tannery wastewater treatment plants (WWTPs) involved in nitrification by Illumina MiSeq sequencing. The results showed that highly diverse communities were present in tannery wastewater. A total of six phyla, including Proteobacteria (37-41%), Bacteroidetes (6.04-16.80), Planctomycetes (3.65-16.55), Chloroflexi (2.51-11.48), Actinobacteria (1.91-9.21), and Acidobacteria (3.04-6.20), were identified as the main phyla, and Proteobacteria dominated in all the samples. Within Proteobacteria, Beta-proteobacteria was the most abundant class, with the sequence percentages ranging from 9.66% to 17.44%. Analysis of the community at the genus level suggested that Thauera, Gp4, Ignavibacterium, Phycisphaera, and Arenimonas were the core genera shared by at least two tannery WWTPs. A detailed analysis of the abundance of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) indicated that Nitrosospira, Nitrosomonas, and Nitrospira were the main AOB and NOB in tannery wastewater, respectively, which exhibited relatively high abundance in all samples. In addition, real-time quantitative PCR was conducted to validate the results by quantifying the abundance of the AOB and total bacteria, and similar results were obtained. Overall, the results presented in this study may provide new insights into our understanding of key microorganisms and the entire community of tannery wastewater and contribute to improving the nitrogen removal efficiency.

• Journal of odor and indoor environment
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• v.16 no.1
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• pp.54-63
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• 2017

The Automobile HVAC system is a habitat for odor-associated fungal communities. We investigated the odor-associated fungal community in an automobile HVAC system using a high-throughput DNA sequencing method. The fungal community structure was evaluated via metagenome analysis. At the phylum level, Ascomycota and Basidiomycota were detected, accounting for 43.41% and 56.49% of the fungal community in the HVAC system, respectively. Columnosphaeria (8.31%), Didymella (5.60%), Davidiella (5.50%), Microxyphium (4.24%), unclassified Pleosporales (2.90%), and Cladosporium (2.79%) were abundant at phylum of Ascomycota and Christiansenia (36.72%), Rhodotorula (10.48%), and Sporidiobolus (2.34%) were abundant at phylum of Basidiomycota. A total of 22 genera of fungi were isolated and identified from the evaporators of the HVAC systems which support fungal growth and biofilm formation. Among them, Cladosporium, Penicillium, Aspergillus, and Alternaria are the most representative odor-associated fungi in HVAC systems. They were reported to form biofilm on the surface of HVAC systems with other bacteria by hypha. In addition, they produce various mVOCs such as 3-methyl-1-butanol, acetic acid, butanoic acid, and methyl isobutyl ketone. Our findings may be useful for extending the understanding of odor-associated fungal communities in automobile HVAC systems.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.4
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• pp.97-104
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• 2021

Despite the practical limitations of calculating the amount of inflow and supply related to the operation of agricultural reservoirs, the role of agricultural reservoirs is gradually being emphasized. In particular, as interest in disaster safety has increased, the demand for preliminary measures to prepare for disasters has been rising, for instance, pre-discharging agricultural reservoirs for flood control. The aim of this study is to analyze the plans for the flood season reservoir operation considering pre-discharge period and water level limit. Accordingly, we optimized the simulation of daily storage using the ratio correction factor (RCFs) and analyzed the amount of inflow and supply using K-HAS. In addition we developed the drought determination coefficient (k) as a indicator of water availability and applied it for supplementing the risk level criteria in the Drought Crisis Response Manual. The results showed that it would be difficult to set the water level limit during the flood period in the situation of little water supply for flood control in agricultural reservoirs. Therefore, it is necessary to operate the reservoir management regulations after measures such as securing additional storage water are established in the future.

• Asia pacific journal of information systems
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• v.31 no.3
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• pp.415-432
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• 2021

The growth of social media has enabled firms to create virtual organizations (online communities) in which value can be co-created with members. Yet, current typologies of firm-sponsored online communities focus either on the firm or participants, and not the interaction between them. This paper provides a systematic review of the online community literature from 2000 to 2018 to develop an understanding of the types of firm-sponsored online communities and the co-creation of value within them. Four types of sponsored online communities are found. These can be differentiated based on the output for the sponsoring firm and the level of self-organization of the communities. This study contributes to the discussion of value co-creation by (i) shedding light on differences among firm-sponsored online community types based on the level and nature of interaction within an online community; and (ii) examining the perceived value co-created through community interactive experiences.

• Journal of Environmental Science International
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• v.23 no.3
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• pp.335-357
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• 2014

This study aims at classifying and interpreting on the vegetation structure and the vegetation transition over 25 years (between 1986 and 2010), and the correlation with the change of some conditions (the vegetation height and coverage on each layer and the climate factors as WI, CI, mean annual temperature, mean annual total precipitation etc.) in the Evergreen Broad-Leaved Forest,, Hong-Do island. The EBLF is classified into five units of vegetation (Hedera rhombea-Machilus thunbergii community (M-M comm.), Castanopsis sieboldii forest (Machilus japonica-Castanopsis sieboldii community; Raphiolepis indica var. umbellata-C. sieboldii community), community (Qa comm.), Carpinus turczaninovii community (Ct comm.), Camellia japonica stand (Cj stand)). The vegetation transition by CCA had high correlation with the height and coverage on each layer and the climate factors, and it did the succession (transition) that the M-M comm. (2010) from Mallotus japonicus community Machilus thunbergii community Carpinus coreana community (Cc comm.) Aucuba japonica community (Aj comm.) Trachelos permum asiaticum var. intermedium-Quercus acuta community (TQ comm.) (1986), the communities of C. sieboldii forest (2010) from Aj comm. TQ comm. Raphiolepis umbellata-Camellia japonica community (RC comm.) (1986), the Qa comm. (2010) from Ardisia japonica-Castanopsis sieboldii community (AC comm.) and TQ comm. (1986), the Ct comm. (2010) from Cc comm. RC comm. Aj comm. Quercus serrata community and the Cj stand (2010) from AC comm. (1986). the height and coverage on each layer are also changed.

• The Korean Journal of Ecology
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• v.26 no.5
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• pp.255-261
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• 2003

To analyze ecological characteristics of the Ulmus pumila community, an on-the-spot survey was conducted in August, 1998 in the Dong River, Gangwon-do, South Korea. The Ulmus pumila community is partially distributed in Dong River's midstream and upper stream. Topographical characteristics of this community are significant in the point bar or sandbank of the river. The community is classified into two types, disturbed and non-disturbed types, by the effect of flooding. The Ulmus pumila community (bush forests of Siberian elms) is a representative community which forms riparian forests, but its distribution is rare in South Korea. Only in Dong River is the Ulmus pumila distributed enough to form a community, and none is known that is lager than this community in South Korea. The non-disturbance type progresses more homogeneously than the disturbance type because it is formed on riverside banks where it is affected less by flooding. We concluded that the Ulmus pumila community in this study area has characteristics of riparian forests. In South Korea, Ulmus pumila community can be regarded as important element of vegetation landscape constituting riparian forests. Specifically, these riparian forests are evaluated as high in conservation value due to their being formed spontaneously. Moreover, Dong River is regarded as the southern limit of Ulmus pumila, which has a northern origin. The species or community needs continuous interests and conservation countermeasures because there are limitations in its spread of distribution by natural or artificial efforts.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.65-73
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• 2018

This study aims to analyzes the Relationship Between Community Consciousness and Residents' Participation in Tourism Development. Starting in 2004, the Rural Tourism Development Project, which has been promoted in Korea, is taking a bottom-up approach that values the participation of residents. And Resident's Participation is also an important criterion for selecting business sites. As the farming community becomes more modern, the community consciousness is declining. But Community consciousness is an important factor for the sustainable maintenance of rural villages. And if community members share a sense of homogeneity, they can identify problems that communities have, and they can solve them with responsibility. Community consciousness can be called the basic infrastructure of residents' participation. Rural tourism feature different characteristics from other tourist areas in that the residential space of local residents is the destination of the tours. As a result, the influence on tourism development is directly affected, so the attitude of local residents is an important success factor unlike other tourism developments. The study analyzed the community consciousness and participation in Tourism Development, which is a significant success factor in rural areas. The survey which included 200 residents of the DMZ Peace Village Site, was concluded that the member's perception and ttachment among Community Consciousness affected the Residents' Participation, and that Economic Influence among tourist development attitudes affected the Residents' Participation. It based on the results in rural tourism development for the residents' participation should be considered with a plan to enhance the economic life satisfaction and promote the economic impact on the area.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.3
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• pp.97-105
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• 2021

Most of the rural development projects for the welfare of residents are mainly new construction and remodeling projects for community buildings such as village halls and senior citizens. However, in the case of the construction industry, it has been studied that 23% of the total carbon dioxide emissions generated in Korea are generated in the building-related sector. (GGIC, 2015) In order to reduce the emission of environmental pollutants resulting from construction of rural community buildings, there is a need to establish a system for rural buildings by predicting the environmental impact. As a result of this study, the emissions of air pollutants from buildings in rural communities were analyzed by dividing into seven stages: material production, construction, operation, maintenance, demolition, recycling, and transportation activities related to disposal. As a result, 12 kg of carbon dioxide (CO), 0.06 kg of carbon monoxide (CO), 0.02 kg of methane (CH), 0.04 kg of nitrogen oxides (NO), 0.02 kg of sulfurous acid gas (SO), and non-methane volatile organics per 1m of buildings in rural communities It was analyzed that 0.02 kg of compound (NMVOC) and 0.00011 kg of nitrous oxide (NO) were released. This study proved that environmentally friendly design is possible with a quantitative methodology for the comparison of operating energy and air pollutant emissions through the design specification change based on the statement of the rural community building. It is considered that it can function as basic data for further research by collecting major structural changes and materials of rural community buildings.