• Korean Journal of Environmental Biology
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• v.26 no.4
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• pp.292-302
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• 2008

The purpose of this study was to analyze the trophic structures and the energy flows in the lower reaches of the Nakdong River using the Ecopath model (Walter et al., 1997). The sampling and analyses were carried out at 6 sampling sites of the lower reaches of the Nakdong River on May and November in 2007. Total of 9 groups detritus, macrophytes, phytoplankton, zooplankton, zoobenthos, Cyprinus carpio, Hemibarbus labeo, Micropterus salmoides and other fishes were considered to assess the trophic relationship, energy flows and interactions among them in the study. As a result, it was concluded that the lower reaches of the Nakdong River was consisted of producers (Detritus, Macrophytes, Phytoplankton), primary consumers (Zooplankton, Zoobenthos, Cyprinus carpio, Hemibarbus labeo, Other fishes) and secondary consumer (Micropterus salmoides). The total system throughput was estimated at 2.7 kg m$^{-2}$ year$^{-1}$ including a consumption of 52%, exports of 9.1%, respiratory flows of 18.0% and flows into detritus of 20.9%. MTI (mixed trophic impacts) analysis demonstrated that Pseudobagrus fulvidraco had positive impact on Cyprinus carpio, Carassius cuvieri and Carassius auratus. On the other hand, other fishes had negative impact on Cyprinus carpio, Carassius cuvieri and Carassius auratus. Also, all the functional groups except detritus had a negative impact on themselves.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.1
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• pp.66-77
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• 2005

We have investigated microclimatic controls on the spatiotemporal variations of net primary production (NPP) of a rugged forested watershed using the process-based biogeochemical model (BIOME-BGC). To validate the model simulation of water and carbon cycles at the plot scale, we have conducted field survey over deciduous broadleaf forest (DBF) and evergreen needleleaf forest (ENF) since 2000. The modeled values of soil temperature, soil moisture and soil respiration showed high correlation with those from the field measurements. The modeled seasonal changes of NPP showed high correlation with air temperature but no significant correlation with water related parameters. The precipitation frequency turned out to be the best climatic factor to explain the annual variation of NPP. Furthermore, NPP of ENF was more sensitive to precipitation frequency than that of DBF. With changes in vegetation cover and topography, the spatial distribution of NPP was of great heterogeneity, which was negatively correlated with the magnitude of NPP. Despite the annual precipitation of 1,400mm, NPP at the study site was constrained by the amount of water available for the vegetation. Such a modeling result should be verified by the field measurements.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.536-544
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• 2017

This study was carried out to find out the physiological activity effect of Sicyos angulatus L. extract which is known as an ecosystem disturbance plant and confirm the availability as a functional cosmetic material. Total polyphenol and flavonoid contents were measured, and DPPH radical scavenging, intracellular ROS, and its inhibitory effect on the expression Nitric oxide of and COX-2 were evaluated. The content of polyphenol and flavonoid was found to be 3.079 mg(CA)/100g and 72 mg(Q)/100g of Sicyos angulatus L. extract and antioxidant activity through high radical scavenging activity was confirmed. ~Significant cytotoxicity was not observed up to a concentration of $100{\mu}g/mL$ in RAW 264.7 cells and HDF cells and concentration-dependent inhibition of ROS production in HDF cells, inhibition of high NO production and inhibition of COX-2 protein expression in RAW 264.7 cells were confirmed. Through these results, we found the possibility of use as a functional cosmetic material with excellent antioxidant effect and antioxidant and anti-inflammatory effects through inhibition of intracellular ROS generation, inhibition of NO generation, and inhibition of COX-2 protein expression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.192-201
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• 2018

This study intends to find efficient support methods for small and medium-sized businesses (SMBs) especially in the increasingly important mobile sector. We investigated regarding perceptions of mobile sector-specific support programs and their current state of usage, and perceptions of the new mobile market and the present conditions of each stage of production based on analysis of a survey that included 204 respondents in each SMB to achieve this goal. Concretely, detections through this research were the reasons for non-selection of support businesses, the future prospective mobile business area, the company's own first-preference item and the reason for the preference, plus new mobile areas of willingness to apply the company's own product and its own first-preference item, and the reason for the preference. In addition, we found out covering costs and revenue size of the maximum-revenue product for each stage (from the first to the fourth stage), the kind of a product's execution method connected to the product (e.g. self-production, outsourcing to another company to produce a product), and the execution method for pre-products. We can suggest a policy regarding efficient support alternatives for SMBs related to the mobile sector thanks to these findings.

• Korean Journal of Ecology and Environment
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• v.50 no.4
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• pp.422-431
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• 2017

The biogeochemical information of riverine organic matter gives a detailed and integrated recording of natural and anthropogenic activity within a watershed. To investigate the changes in quality and quantity of organic carbon transporting from mountain to ocean via river channels, we estimated the concentrations of dissolved (DOC) and particulate organic carbon (POC), and then traced the source origin of POC using stable carbon isotopes ratio before and after summer rainfalls in the Tamjin River and Ganjin Bay, Korea. Along the small watershed, a total of 13 sites including headwaters, dam reservoir, river and estuary were established for the study. We found some interesting findings in the aspect of distribution of DOC/POC concentration changing their origin sources dynamically flowing downstream. In particular, the river channel transport downstream mainly DOC to river mouth, although upper dam reservoir increased POC concentration by phytoplankton production in summer. Whereas, in the river mouth and estuary, POC was dominated not only by local supply from nearby reed saltmarsh, but also by marine phytoplankton production, respectively. The findings can contribute to increasing the understanding of riverine organic carbon transport in upper large dam and lower open estuary system.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.4
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• pp.219-233
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• 2013

We employed the ecological niche modeling framework using GARP (Genetic Algorithm for Ruleset Production) to model the current and future geographic distribution of Pinus densiflora based on environmental predictor variable datasets such as climate data including the RCP 8.5 emission climate change scenario, geographic and topographic characteristics, soil and geological properties, and MODIS enhanced vegetation index (EVI) at 4 $km^2$ resolution. National Forest Inventory (NFI) derived occurrence and abundance records from about 4,000 survey sites across the whole country were used for response variables. The current and future potential geographic distribution of Pinus densiflora, one of the tree species dominating the present Korean forest was modeled and mapped. Future models under RCP 8.5 scenarios for Pinus densiflora suggest large areas predicted under current climate conditions may be contracted by 2090 showing range shifts northward and to higher altitudes. Area Under Curve (AUC) values of the modeled result was 0.67. Overall, the results of this study were successful in showing the current distribution of major tree species and projecting their future changes. However, there are still many possible limitations and uncertainties arising from the select of the presence-absence data and the environmental predictor variables for model input. Nevertheless, ecological niche modeling can be a useful tool for exploring and mapping the potential response of the tree species to climate change. The final models in this study may be used to identify potential distribution of the tree species based on the future climate scenarios, which can help forest managers to decide where to allocate effort in the management of forest ecosystem under climate change in Korea.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.23-29
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• 2018

The litter production, the nutrient concentration of each component of litterfall, and the amounts of nutrient into the forest floor via litterfall were assessed for 5 years from January 2009 through December 2013 in a Pinus densiflora forest in Mt. Worak National Park. The average amounts of leaf litter, branch and bark, reproductive organs(flowers and cones), and miscellaneous categories for 5 years were $1.940{\pm}0.21$, $0.505{\pm}0.15$, $0.259{\pm}0.09$, and $0.737{\pm}0.14t\;ha^{-1}yr^{-1}$, respectively. The average percentage of leaf litter, branch and bark, reproductive organs and miscellaneous categories for 5 years were 56.4, 14.7, 7.5, and 21.4%, respectively. The amounts of total litterfall in 2009, 2010, 2011, 2012, and 2013 were 2.810, 3.796, 3.268, 3.284, and $4.045ton\;ha^{-1}yr^{-1}$, respectively. The average amounts of litterfall for 5 years were $3.441{\pm}0.4ton\;ha^{-1}yr^{-1}$. The average amounts of N, P, K, Ca, and Mg returned to the forest floor via litterfall for 5 years in this Pinus densiflora forest were $22.73{\pm}4.92$, $1.05{\pm}0.42$, $4.26{\pm}1.69$, $8.48{\pm}4.62$, and $2.42{\pm}1.01kg\;ha^{-1}yr^{-1}$, respectively.

• Korean Journal of Environment and Ecology
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• v.25 no.4
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• pp.573-580
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• 2011

Litter production, nutrient concentration of each component of litterfall and amount of nutrients input to forest floor via litterfall were investigated for four years from May 2005 through April 2009 in Quercus variabilis forest at Mt. Worak National Park. Amount of litterfall in 2005, 2006, 2007, 2008 were 5.181, 5.372, 5.314, 5.361 ton $ha^{-1}yr^{-1}$, respectively. Average amount of litterfall for four years was 5.307${\pm}$0.09 ton $ha^{-1}yr^{-1}$. Average percentage of leaf litter, branch and bark, reproductive organ and the miscellaneous for four years were 67.5${\pm}$1.9, 13.3${\pm}$0.8, 10.1${\pm}$0.5 and 9.1${\pm}$1.2%, respectively. Average amount of N, P, K, Ca and Mg returned to forest floor via litterfall for four years in this Q. variabilis forest were 44.47${\pm}$6.70, 2.50${\pm}$0.25, 12.26${\pm}$0.30, 17.23${\pm}$2.32 and 9.56${\pm}$0.54 kg $ha^{-1}yr^{-1}$, respectively.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.242-252
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• 2016

A process-based ecosystem model, BIOME-BGC, was applied to simulate seasonal and inter-annual dynamics of carbon and water processes for potential evergreen needleleaf forest (ENF) biome in Korea. Two simulation sites, Milyang and Unljin, were selected to reflect warm-and-dry and cool-and-wet climate regimes, where massive diebacks of pines including Pinus densiflora, P. koraiensis and P thunbergii, were observed in 2009 and 2014, respectively. Standard Precipitation Index (SPI) showed periodic drought occurrence at every 5 years or so for both sites. Since mid-2000s, droughts occurred with hotter climate condition. Among many model variables, Cpool (i.e., a temporary carbon pool reserving photosynthetic compounds before allocations for new tissue production) was identified as a useful proxy variable of tree carbon starvation caused by reduction of gross primary production (GPP) and/or increase of maintenance respiration (Rm). Temporal Cpool variation agreed well with timings of pine tree diebacks for both sites. Though water stress was important, winter- and spring-time warmer temperature also played critical roles in reduction of Cpool, especially for the cool-and-wet Uljin. Shallow soil depth intensified the drought effect, which was, however, marginal for soil depth shallower than 0.5 m. Our modeling analysis implicates seasonal drought and warmer climate can intensify vulnerability of ENF dieback in Korea, especially for shallower soils, in which multi-year continued stress is of concern more than short-term episodic stress.

• Journal of the Korean Institute of Landscape Architecture
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• v.13 no.1
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• pp.79-94
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• 1985

This study was carried out to give basic information about the environmental conservation in Masan District. It included the actual vegetation the degree of human disturbance of vegetation, plant biomass and biomass production. The natural vegetation was nonexistent and the major plant communities of the secondary forest was P. thunbergii-Q. acutissima and Quercus forest. P. thunbergii-Q. acutissima community area was 29.2% of Masan District and the secondary forest and the afforestation area was 48% and 13% of Masan District respectively. The ecological diversity of the plant community was high value in Q. acutissima- P. thunbergii, Q.aliena and Carpinus laxiflora-Q.variabilis communicty. As the investigation of the ecological succession in Masan Forest, P. thunbergii community is edaphic climax and mixed forest will be changed gradually dominant species of Quercus species. It was implied that Genus Quercus hadnever beenso easily taken ever by the Genus Pinus which forms the edaphic climax at vast areas of forest land. In the degree of human disturbance of vegetation, the degree 7 (secondary forest 1) was 52.8% and the green spaces in Masan cover 65%, which nongreen spaces 35 %. Total amount of plant biomass produced from Masan District was estimated to be 160, 470.95 tons. Annual Production of dry matter biomass amounts to be 32,940.64 tons. Estimated amount for O$_2$produced annually from the vegetated area in Masan was 34,856 tons.