• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.66-76
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• 2011

The Sightseeing ITS is defined as a system that gives tourists and inhabitants the information concerned with road network conditions, parking, sightseeing spots, and travel time in the relevant area. When focusing on tourists' excursion behaviors in sightseeing areas, however, it is sometimes found that they feel much annoyed with insufficient information about the area. While they also have a variety of needs to get information and make a decision about their excursions, it becomes one of important subjects to understand the actual circumstances of their information usage and to identify the causal relationship between their excursion patterns and the obtained information. This paper aims to investigate basic issues toward development of Sightseeing ITS and to modify an analytical model of tourist's excursion behavior considering information usage at Fuji five lakes Area, which is a representative sightseeing place in Japan. The relationship was analyzed using a structural equation model: information usage at the scheduling stage has an impact on tourists' individual cognition of the sightseeing area, tourists' individual cognition affects information usage at the excursion stage, and information usage at the excursion stage affects behavior during excursions. It is found that tourists' decision making behaviors on their excursion tend to depend on the information usage. This implies essential results to construct effective and customer oriented ITS.

• Progress in Superconductivity and Cryogenics
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• v.22 no.2
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• pp.7-11
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• 2020

When rivers and lakes are contaminated with numerous contaminants, usually the contaminants are finally deposited on the sediments of the waterbody. Many clean up technologies have been developed for the contaminated sediments. Among several technologies dredging is one of the best methods because dredging removes all the contaminated sediments from the water and the contaminated sediments can be completely treated with physical and chemical methods. However the most worried phenomenon is suspension of fine particles during the dredging process. The suspended particle can release contaminants into water and resulted in spread of the contaminants and the increase of risk due to the resuspension of the precipitated contaminants such as heavy metals and toxic organic compounds. Therefore the success of the dredging process depends on the prevention of resuspension of fine particles. Advanced dredging processes employ pumping the sediment with water onto a ship and release the turbid water pumped with sediment into waterbody after collection of sediment solids. Before release of the turbid water into lake or river, just a few minutes allowed to precipitate the suspended particle due to the limited area on a dredging ship. However the fine particle cannot be removed by the gravitational settling over a few minutes. Environmental technology such as coagulation and precipitation could be applied for the settling of fine particles. However, the process needs coagulants and big settling tanks. For the quick settling of the fine particles suspended during dredging process magnetic separation has been tested in current study. Magnetic force increased the settling velocity and the increased settling process can reduce the volume of settling tank usually located in a ship for dredging. The magnetic assisted settling also decreased the heavy metal release through the turbid water by precipitating highly contaminated particles with magnetic force.

• Journal of Ecology and Environment
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• v.32 no.4
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• pp.257-265
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• 2009

We estimated monthly and annual secondary productivity of pelagic zooplankton in Lake Paldang and Lake Cheongpyong. Secondary productivity was calculated by combining estimated zooplankton biomass and biomass-specific productivity for each site and depth from March to November 2008. In addition to somatic production, we measured production of eggs and exuviae for three dominant species: Daphnia galeata, Bosmina longirostris, Cyclops sp. In terms of biomass, B. longirostris was dominant in Lake Paldang in April and May, B. longirostris showed explosive biomass growth, especially in May. In June and July, B. longirostris and D. galeata were both dominant. Lake Cheongpyeong showed much lower zooplankton biomass than Lake Paldang. In August, there was little or no biomass in both lakes probably due to heavy rain. The Gyeongan River contributed most of the secondary productivity and B. longirostris contributed the most secondary productivity in Lake Paldang. D. galeata also contributed in the Gyeongan River, the South Han River and at the Paldang Dam in spring and fall. Overall, Lake Cheongpyeong showed lower secondary productivity than Lake Paldang. B. longirostris made the largest contribution to secondary productivity in the Cheongpyeong Dam area while D. galeata contributed the most near Nami Island. Somatic production constituted ~80% of the total secondary productivity (the sum of somatic, egg and exuvia production) for D. galeata and B. longirostris. Although production-to-biomass (P/B) ratios were usually <<1 B. longirostris sometimes showed very high P/B ratios, probably due to fish predation. D. galeata showed much lower P/B ratios than B. longirostris after the summer at most sites.

• Journal of Ecology and Environment
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• v.41 no.8
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• pp.213-222
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• 2017

Background: This study was conducted to assess the physicochemical water quality and the altitudinal distribution of low-temperature and mountain epilithic diatom (LTMD) community in Buk and Hangae streams that are located in Seorak Mountain with the height of 1708 m in Korea. And the community characteristics of LTMD found in the Buk and Hangae streams were compared to that of LTMD from the Han River system. Results: The physicochemical water qualities of Buk and Hangae streams were determined to be very clean. As a result of analyzing the community composition, 135 taxa of epilithic diatoms were determined, and 22 taxa appeared including Hannaea arcus var. subarcus which are known to have low-temperature and mountain ecological characteristics in the literatures. The relative frequencies of LTMD were 37.0~0.9% range from the upper to lower regions. Although Diatoma tenuis, Eunotia minor, and Gomphonema affine are known to be ubiquitous in streams and lakes, in this research, the three taxa were added into low-temperature and mountain epilithic diatom, since D. tenuis and E. minor appeared only in altitudes above 600 m, and G. affine had the highest relative frequency during spring and fall in altitudes above 700 m, when water temperature was around $10^{\circ}C$. Conclusions: Among the 24 taxa of low-temperature and mountain epilithic diatom (LTMD) (including the 3 taxa added in this study), 14 taxa (Diatoma hyemalis, D. mesodon, D. tenuis, Hannaea arcus, H. arcus var. subarcus, Ulnaria inaequalis, Eunotia bilunaris, E. implicata, E. minor, E. muscicola, E. silvahercynia, E. septena, Delicata delicatula, and Gomphonema affine) represented the characteristics of LTMD very well; they grow best in water temperatures below $15^{\circ}C$ in Buk and Hangae streams and Han River system.

• Journal of Environmental Science International
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• v.24 no.9
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• pp.1101-1121
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• 2015

The seasonal variation of phytoplankton communities and its standing crops in accordance with environmental factors were investigated at Yeongrang-ho, Cheongcho-ho, Mae-ho and Hyang-ho which are located in the East coast of Korea during April to October 2011. High concentrations of T-N and T-P were observed in four lagoons due to the inflowing nutrients from farmlands and residential areas near lagoons. Nutrient salts mainly composed of nitrogen and phosphate caused the eutrophication of the lakes, leading to the robust growth of phytoplankton. During the period of investigation, 64 to 107 taxa of phytoplankton were observed in four lagoons. Diatoms were the most dominant species with high density. Non-point pollution source was estimated as the main cause of water pollution of lagoons. Trophic states of lagoons evaluated using the value of TSI and TSIKO indicated that all the investigated lagoons were in the eutrophication state.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.393-399
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• 2004

Useful genes can be Screened from various environments by construction of metagenomic DNA libraries. In this study, water samples were collected from several lakes in mid Korea, and analyzed by T-RFLP to examine diversities of the microbial communities. The crude DNAs r were extracted by the SDS-based freezing-thawing method, and then further purified using an $UltraClean^{TM}$ kit (MoBio, USA). The metagenomic libraries were constructed with the DNAs partially digested with EcoR I, BamH I, and Sac II in Escherichia coli DH 10B using the pBACe3.6 vector. About 44.0 Mb of metagenomic libraries were obtained with average inserts 13-15 kb in size. The bphC genes responsible for degradation of aromatic hydrocarbons via mets-cleavage were identified from the metagenomic libraries by colony hybridization using the bphC specific sequence as a probe. The 2,3-dihydroxybiphenyl (2, 3-DHBP) dioxygenase gene (bphC ), capable of degradation of 2,3-DHBP, was cloned and its nucleotide Sequences analyzed. The genes consisted of 966 and 897 base pairs with an ATG initiation codon and a TGA termination codon. The activity of the 2,3-DHBP dioxygenase was highly expressed to 2,3-DHBP and Showed a broad substrate range to 2,3-DHBP, catechol, 3-methylcatechol and 4-methylcatechol. These results in-dicated that the bphC gene identified from the metagenomes derived from lake water might be useful in the development of a potent strain for degradation of aromatic pollutants.

• Journal of Environmental Science International
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• v.25 no.3
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• pp.361-371
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• 2016

Ministry of Environment has been operating water quality monitoring network in order to obtain the basic data for the water environment policies and comprehensively understand the water quality status of public water bodies such as rivers and lakes. The observed water quality data is very important to analyze by applying statistical methods because there are seasonal fluctuations. Typically, monthly water quality data has to analyze that the transition comprise a periodicity since the change has the periodicity according to the change of seasons. In this study, trends, SOM and RDA analysis were performed at the Mulgeum station using water quality data for temperature, BOD, COD, pH, SS, T-N, T-P, Chl-a and Colon-bacterium observed from 1989 to 2013 in the Nakdong River. As a result of trends, SOM and RDA, the Mulgeum station was found that the water quality is improved, but caution is required in order to ensure safe water supply because concentrations in water quality were higher in the early spring(1~3 month) the most.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.1
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• pp.61-65
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• 2006

This paper is concerned with a quantitative computational trust model which lakes into account multiple evaluation criteria and uses the recommendation from others in order to get the trust value for entities. In the proposed trust model, the trust for an entity is defined as the expectation for the entity to yield satisfactory outcomes in the given situation. Once an interaction has been made with an entity, it is assumed that outcomes are observed with respect to evaluation criteria. When the trust information is needed, the satisfaction degree, which is the probability to generate satisfactory outcomes for each evaluation criterion, is computed based on the outcome probability distributions and the entity's preference degrees on the outcomes. Then, the satisfaction degrees for evaluation criteria are aggregated into a trust value. At that time, the reputation information is also incorporated into the trust value. This paper presents in detail how the trust model works.

• Interaction and multiscale mechanics
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• v.2 no.3
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• pp.321-332
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• 2009

Recent development in composites containing phase-transforming particles, such as vanadium dioxide or barium titanate, reveals the overall stiffness and viscoelastic damping of the composites may be unbounded (Lakes et al. 2001, Jaglinski et al. 2007). Negative stiffness is induced from phase transformation predicted by the Landau phase transformation theory. Although this unbounded phenomenon is theoretically supported with the composite homogenization theory, detailed stress analyses of the composites are still lacking. In this work, we analyze the stress distribution of the Hashin-Shtrikman (HS) composite and its two-dimensional variant, namely a circular inclusion in a square plate, under the assumption that the Young's modulus of the inclusion is negative. Assumption of negative stiffness is a priori in the present analysis. For stress analysis, a closed form solution for the HS model and finite element solutions for the 2D composite are presented. A static loading condition is adopted to estimate the effective modulus of the composites by the ratio of stress to average strain on the loading edges. It is found that the interfacial stresses between the circular inclusion and matrix increase dramatically when the negative stiffness is so tuned that overall stiffness is unbounded. Furthermore, it is found that stress distributions in the inclusion are not uniform, contrary to Eshelby's theorem, which states, for two-phase, infinite composites, the inclusion's stress distribution is uniform when the shape of the inclusion has higher symmetry than an ellipse. The stability of the composites is discussed from the viewpoint of deterioration of perfect interface conditions due to excessive interfacial stresses.

• Journal of the Korean Chemical Society
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• v.48 no.5
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• pp.467-472
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• 2004

Cyanobacterial toxins, microcystins which exist in korean lakes show strong toxicity to fish, cattles and human. In this study, we tried to degrade microcystin LR using various chemical oxidants, Chlorine, Potassium permanganate and Hydrogen Peroxide. The detection method for the concentrations of microcystin LR in water samples was Enzyme-Linked Immunosorbent Assay (ELISA) method using the monoclonal antibody of microcystin. Chlorine degraded microcystin LR effectively at the concentration of 800 pg/mL microcystin LR and 12 ppm chlorine. The reaction took 40 minutes at pH 7. Potassium Permanganate also degraded microcystin LR successfully at the concentration of 2000 pg/mL microcystin LR and 1.2 ppm chlorine. The degradation reaction took 60 minutes at pH 7. In the case of hydrogen peroxide, the degradation rate of microcystin LR was very slow because of the slow reaction rate.