• Food Science and Industry
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• v.55 no.3
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• pp.284-300
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• 2022

Indigenous fermented foods have played a vital role in human history, and continue to offer a multitude of diverse sensory characteristics. According to earthenware relic, the fermented fisheries products might be consumed in Korean peninsula from Paleolithic period. The traditional Korean fermented fish products are classified into four groups; Jeot-gal (sik-hae), Aek-jeot, Seasoned Jeot-gal, and Seasoned Aek-jeot. Jeot-gal is a fermented fishery with salt. Aek-jeot is a liquid part of Jeot-gal. Sik-hae is manufactured by fementing fishery with salt, cereal, malt powder, etc. Seasoned Jeot-gal is a salt-seasoned fish with red pepper powder, garlic, onion, etc. Seasoned Aek-jeot is a seasoned product by adding "salt-water" or "condiment" to Aek-jeot. The fermented fisheries industry has traditionally been succeeded mainly in a cottage scale to the middle of 20th century. Thereafter, together with the development of pelagic fishery, the fermented fisheries industry also developed constantly to an enterprise size.

• East Asian mathematical journal
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• v.38 no.4
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• pp.379-396
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• 2022

In this paper, we investigate distribution strategies in the Egyptian fraction, and through this, we examine the distribution strategies of (fraction)÷(fraction) and then provide some educational implications. The (natural number)÷(natural number) of the sharing situation has the meaning of 'share' per unit, which can be seen as a situation where the unit ratio is determined. These concepts can also naturally be extended to the case of (fraction)÷(fraction) by some problem posing situations. That is to say, the case of (fraction)÷(fraction) can be deduced the case (natural number)÷(natural number) by the re-statement of the problem.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.415-420
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• 2022

It is essential that continual assessments of the impact of mine-derived water as a long-lasting burden on freshwater environments. Abundance-based evaluations of benthic macroinvertebrates have been conducted to evaluate anthropogenic disturbances and devise policies to reduce their impact. In this study, the status of a stream habitat was evaluated based on the body length and biomass weight of benthic macroinvertebrates of the family Baetidae. Following the renewal of the mining water treatment plant, the abundance of Baetidae assemblages recovered to a level comparable to that of a reference site. However, relatively low values were found for both body length and biomass weight in Baetidae species inhabiting the reddened streambed area, suggesting that the habitat has not yet been completely recovered despite the recovery of the abundance of the Baetidae assemblages. Therefore, continuous investigation and evaluation of this disturbed stream are necessary until their growth conditions of the habitat have functionally recovered.

• Journal of Korean Association for Spatial Structures
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• v.23 no.4
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• pp.59-69
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• 2023

Recently, the occurrence frequency of earthquake has increased in Korea, and the interests for seismic reinforcement of existing school buildings have been raised. To this end, the seismic performance evaluations for school buildings that did not accomplish the seismic design are required. In particular, this study checks the eigenvalue analysis, pushover curves, maximum base shears, performance points and story drift ratios, and then analyzes the seismic performance characteristics according to bracing configuration of steel frame system reinforcement. Also, this study presents the practical field application methods through the comparison of analysis results for the seismic performance characteristics.

• Journal of Korean Association for Spatial Structures
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• v.24 no.2
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• pp.43-52
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• 2024

Phayathonzu temple in Myanmar was made of masonry bricks, and so it was vulnerable to lateral load such as earthquake. Especially, it has many difficulties in structural modeling and dynamic analysis because the discontinuous characteristics of masonry structure should be considered. So, it is necessary to provide the seismic performance evaluation technology through the inelastic dynamic modeling and analysis under earthquake loads for the safety security of masonry brick temple. Therefore, this study analyzes the seismic behavior characteristics and evaluates the seismic performance for the 479 structure with many cracks and deformations. Through the evaluation results, we found out the structural weak parts on earthquake loads.

• Korean Journal of Ecology and Environment
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• v.34 no.1 s.93
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• pp.30-44
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• 2001

In this study limnological characteristics of Lake Juam was surveyed from June 1993 to May 1994 in order to provides important information regarding water resources. Secchi disc transparency, epilimnetic chlorophyll a (chi-a), total nitrogen (TN), total phosphorus (TP) concentration and primary productivity were in the range of $2.0{\sim}4.5\;m$, $0.9{\sim}13.6\;mgChl/m^3$, 0.78$\{sim}$2.32 mgN/l, $11{\sim}56\;mgP/m^3$, $270{\sim}2.160\;mgCm^{-2}\;day^{-1}$, respectively. On the basis of TP, Chl-a and Secchi disc depth, the trophic state of Lake Juam can be classied as mesotrophic lake. The phosphorus inputs from non-point sources are concentrated in heavy rain episodes during the monsoon season. As a result, phosphorus concentration are higher in summer than in winter. TP loading from the watershed were estimated to be $0.9\;gPm^{-2}yr^{-1}$, which correspond to a boundary of the critical loading ($1.0\;gPm^{-2}yr^{-1}$) for eutrophication. From the results of the algal assay, both phosphous and nitrogen act as limiting nutrients in algal growth. The seasonal succession of phytoplankton community structure in Lake Juam was similar to that observed in other temperate lakes. Diatoms (Asterionella formosa and Aulacoseira granulate var. angustissima)fujacofeira BraHuJafa uar. aHgusHrsiaia) weredominant in spring and winter, cyanobacteria) were dominant in warm season. The organic carbon, nitrogen and phosphorus content of lake sediment were $9.5{\sim}14.0\;mgC/g$, $1.01{\sim}1.82\;mgN/g$ and $0.51{\sim}0.65\;mgP/g$, respectively. The allochthonous organic carbon loading from the watershed and autochthonous organic carbon loading by primary production of phytoplankton were determined to be 1,122 tC/yr and 6,718 tC/yr, respectively. To prevent eutrophication of Lake Juam, nutrient management of watershed should be focus on reduction of fertilizer application, proper treatment of manure, and conservation of topsoil as well as point source.

• Journal of Environmental Impact Assessment
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• v.21 no.3
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• pp.483-501
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• 2012

The purpose of this study was to apply a multi-metric model of Lentic Ecosystem Health Assessments(LEHA) for environmental impact assessments of Cheongpyung Reservoir during 2005 - 2006 and assessed the ecological model values. The ecosystem model of LEHA was composed of eleven metrics such as biological parameters($B_p$), physical parameters($P_p$), and chemical parameters($C_p$), and determined the rank of ecological health by the criteria. The variables of $B_p$ were metrics of % sensitive species($M_2$, NMS) and insectivore species($M_5$, % $I_n$), which decrease as the water quality degradates, and these metric values were low as 1.5% and 32.4%, respectively. In contrast, the proportions of tolerant species and omnivore species as the other $B_p$ parameters were 43% and 62%, respectively, which indicate a degradation and disturbance of the ecosystem. Riparian vegetation coverage($M_9$, % $V_c$) as a variable of $P_p$, were higher in the 2nd than 1st survey, and decreased toward the dam site from the headwaters. This was due to a habitat simplification(modifications) by frequent bottom dredging of sand and rocks. The variables of $C_p$ were two metrics of specific conductivity($M_{10}$, $C_I$) as an indicator of ionic contents(cations and anions) and the Trophic State Index(TSI) based on chlorophyll-a($M_{11}$, $TSI_{CHL}$) as an indicator of trophic state. These metric values of $C_p$ had high temporal variations, but low spatial variations on the main axis of the reservoir along with the ecological health of a good condition. The environmental impact assessments using the LEHA multi-metric model indicated that the model values of LEHA averaged 30.7 in 1st survey(fair - poor condition) vs. 28 in 2nd survey(poor condition), indicating a temporal variation of the ecological health. The model values of LEHA showed a minimum(28) in the lacustrine zone(S5) and ranged from 29 to 30 in the other locations sampled, indicating a low longitudinal variation. Overall, environmental impact assessments, based on LEHA model, suggest that chemical water quality conditions were in good, but biological conditions were disturbed due to habitat modifications by frequent dredgings in the system.

• Journal of the Korean earth science society
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• v.21 no.5
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• pp.563-582
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• 2000

Two Cretaceous(80-90 Ma) non-marine sedimentary basins, Namyang and Tando Basins, are distributed in the Namyang area, Hwaseonggun and in the Tando area, Ansanshi, Kyungki Province, Korea. The Namyang and Tando Basins are composed of 10 facies, which are pooped into 5 facies associations(FA). FA I consists of massive conglomerate facies, normally graded conglomerate facies and reversely graded conglomerate facies, which is interpreted to have been formed by laminated sandstone facies, massive conglomerate facies(channelized), which is thought to have been formed by sheet flow, stream flow and suspension sedimentation in an alluvial/braided plain environment. FA III consists of massive mudstone(pebbly) facies, laminated mudstone facies, massive sandstone facies and is interbedded by channel-fill conglomerate. It is interpreted to have been deposited by suspension settling during flooding and channel-fill deposition in a floodplain environment. FA IV consists of massive conglomerate facies, normally graded conglomerate facies, massive sandstone facies, normally graded sandstone facies, and laminated sandstone facies and is interbedded with mudstone facies. It is thought to have been deposited by debris flow and turbidity current in a fan-delta environment. FA V consists of massive mudstone facies, laminated mudstone facies, laminated sandstone facies and is interbedded by massive conglomerate bed. It is thought to have been formed by suspension sedimentation and low-density turbidity current in a lake. In the Namyang Basin FA I is distributed in the eastern and southern margin of the basin, FA II in the middle part of the basin as north-south tending band. and FA III in the western part. In the Tando Basin FA II is distributed in the middle part of eastern margin and in the northwestern margin, FA IV in the southwestern part, and FA V in the central part. Correlation of the facies associations shows that FA I and II in the Namyang Basin are distributed in the lower to middle part of stratigraphic sequence and FA III in the upper part of the sequence whereas FA II and IV in the Tando Basin are in the lower to middle part and FA V in the upper part of the sequence. These patterns of facies associations distribution suggest that the Namyang Basin was developed as an alluvial fan and alluvial/braided plain at first and then evolved into a floodplain whereas the Tando Basin was developed as a fan-delta and alluvial/braided plain at first and then evolved into a lake environment.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.286-294
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• 2003

This study was attempted to understand seasonal dynamics of phyto- and zooplankton communities in shallow, eutrophic Lake llgam and to compare them with the PEG (Plankton Ecology Group) model. Seasonal succession pattern of phytoplankton community was similar to PEG model as Chlorophyceae and Baciliphyceae increase during spring and autumn fellowed by increase of Cyanophyceae. However, based on the cell density and biomass, a dominant phytoplankton community differed with PEG model: Cyanophyceae had been a dominant community throughout a year, except for ice-cover period during which Chlorophyceae was a dominant group. In spring, when ice melted and dissolved nutrients in water column increased, the increase of Chlorophyceae occurred: when nutrients (DIN and DIP) rapidly decreased, Cyanophyceae increase occurred. Microcystis, Oscillatoria, Lyngbya, Merismopedia were maior dominant species of Cyanophyceae and their cell density and/or biomass was the highest in October 2000 (12.9${\pm}$5.8${\times}10^5$ cells/ml, 3.5${\pm}$0.9${\times}10^3{\mu}gC/l$). Cyanophyceae biomass showed positive relationship with chlorophyll a ($r^2$ = 0.71,P< 0.001) and TP concentration ($r^2$ = 0.62, P< 0.001). Small-sized rotifers such as Keratella cochlearis, increased between March and May when Chlorophyceae increased. Both high standing crop of copepods and cladocerans, such as Diaphanosoma brachyrum and Bosmina longirostris occurred between June and September accompanied with the increase of Dinophyceae and Bacillariophyceae. There was no evidence that clear-water phase was caused by zooplankton grazing. The diversity and evenness index of phyto- and/or zooplankton increased with chlorophyll a concentration. These results suggest zooplankton grazing and limiting nutrient deficiency could lead to change of phytoplankton biomass, but not the phytoplankton community in Lake llgam.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.382-394
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• 2008

The objective of this study was to analyze temporal trends of water chemistry and spatial heterogeneity between the dam site (Daecheong Reservoir, S1) and the downstream (S2$\sim$S4) using water quality dataset (obtained from the Ministry of Environment, Korea) during 2000$\sim$2007. Water quality, based on eight physical and chemical parameters, varied largely depending on the years, sampling sites, and the discharge volume. Conductivity and nutrients (TN and TP) showed a decreasing trend in the downstream (S4) rather than the dam site during the monsoon. Spatial variation increased toward downstream (S4) from Daecheong Reservoir (S1). Also, BOD and COD increased toward downstream. Because of input of nutrient and pollutant nearby S1, lentic ecosystem in monsoon, BOD and COD were slightly increased. whereas relatively decreased in S4, lotic ecosystem in monsoon, by dilution effect of nutrient and pollutant by discharge from upper dam, S1. Spatial variation of SS increased toward downstream (S4) by the side of Daecheong Reservoir (S1). Based on the dataset, efficient water quality management in the point source tributary streams is required for better water quality of downstream. Monthly characteristics of DO showed the lowest value in the monsoon that tend to increase water temperature. DO was lowest in October at S1 because turbid water, input to the Daecheong Reservoir in the monsoon affect to the postmonsoon period. In contrast, water temperature increased toward summer monsoon, in spite of some differences showed between S1 and S4 environment. Overall, the characteristics of water quality in downstream region have close correlation with discharge amount of Daecheong Reservoir. Thus, those characteristics can explain that discharge control of upper dam mainly affect to the water quality variation in downstream reach.