• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.1033-1041
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• 2014

Rapid urbanization of Korea was an unprecedented example in the world and urban population increased significantly. As a result, unbalanced distribution of population is serious problem in Korea because approximately 50% of the population is concentrated in the capital area that is 10% of nation's territory, thereby occurring various urban problems including UHI. Hence, Sejong Special Autonomous City was inaugurated officially on 2 July 2012 in order to decentralize population of capital area and induce more balanced regional development. The Sejong City has been changed drastically over a period of years as developed practically since the late 2000's and is expected to have new problems of urbanization. The land cover change due to urbanization is the main cause of UHI that urban area is significantly warmer than its surrounding areas and UHI is not only affecting urban climate change but also natural environment. So the purpose of this research is to analyze level of urbanization and UHI effect and to provide the correlation analysis between Land Surface Temperature and spectral indices. To achieve this, satellite imagery from LANDSAT were used. NDVI, NDBI, and UI were calculated using red, near-infrared, mid-infrared ($0.63{\mu}m-1.75{\mu}m$) images and LST was retrieved utilizing thermal infrared ($10.4{\mu}m-12.5{\mu}m$) image. Based on each index and LST, Changes of NDVI, UI and UHI through TVI were analyzed in Sejong City. UHI effect increased around newly constructed multi-functional administrative city, the correlation between LST and NDVI was negative and UI was strong positive.

• Journal of Distribution Science
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• v.11 no.4
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• pp.51-60
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• 2013

Purpose - The objective of this paper is to investigate the effect of asset specificity, the level of information sharing, the importance of information sharing, and an integrated collaborative environment on supply chain performance. Research design, data, and methodology - Data collection was implemented as follows: questionnaires were distributed to 250 companies that have business ties with Halla Climate Control Corporation. The empirical study to test our hypothesis was based on statistical analysis (using SPSS 18.0 and AMOS 18.0). The hypothesis of this paper is that the asset specificity variable has positive effects on the following variables: Level of information sharing, the importance of information sharing, and integrated collaborative environment. Moreover the variables, the level of information sharing, and the importance of information sharing are strongly influenced by the variable integrated collaborative environment, and these when combined, have an effect on the dependent variable, supply chain performance. We tested our hypothesized model utilizing path analysis with latent variables. Results - According to the results of our analysis, hypothesis H1, which tests whether there is a relationship between asset specificity and the integrated collaborative environment, is supported at the 0.01 level. Hypotheses H2 and H3 were also confirmed, and asset specificity had positive effects (+) on the level of information sharing variable. The importance of the information sharing variable was statistically significant at the 0.01 level. Hypotheses H4 and H5 posited that the integrated collaborative environment variable would have a positive effect on the level of information sharing; the importance of information sharing variable was strongly supported statistically, with a significant p-value below. Moreover, the level of information sharing (H6), and the importance of information sharing (H7) variables also had a statistically relevant influence on supply chain performance. As a result, existence of a collaborative system between companies would influence supply chain performance by strengthening real-time information access and information sharing. Thus, it is important to construct a collaborative environment where information sharing among companies and cooperation is possible. Conclusions - First, with rapid changes in the business environment, it becomes necessary for enterprises to acquire the right information in order to properly implement SCM. For successful SCM, firms should understand the importance of collaboration with supply chain partners and an internally built collaboration system, which in turn will better promote a partnership commitment with suppliers as well as collaborative integration with buyers. A collaborative system, as we suggest in this paper, facilitates the maintenance of a long-term relationship of trust, and can help reinforce information sharing. Second, it is necessary to increase information sharing over time via a collaborative system so that employees of the suppliers become aware of the system. The more proactive and positive attitudes are towards such a collaborative system by the managerial group, the higher the level of information sharing will be among the users. Successful SCM performance is achieved by information sharing through a collaborative environment rather than by investing only in setting up an information system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.679-686
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• 2010

To investigate the contribution of macroalgae to biogeochemical nutrients and carbon cycles, we measured the uptake rates of nutrients and $CO_2$ by Undaria pinnatifida using an incubation method in an acrylic chamber. From January to March 2010, U. pinnatifida was sampled at Ilkwang, a well-known area of macroalgae culture in Korea. The initial and final concentrations of nutrients, dissolved oxygen, total alkalinity, and pH of the chamber water were measured, and production/uptake rates were calculated using concentration changes, chamber volume, and incubation time. The production rate of dissolved oxygen by U. pinnatifida (n = 32) was about $5.4{\pm}4.0\;{\mu}mol\;g_{fw}^{-1\;}h^{-1}$. The uptake rate of total dissolved inorganic carbon (TDIC), calculated by total alkalinity and pH, was $7.9{\pm}6.5\;{\mu}mol\;g_{fw}^{-1}\;h^{-1}$. Nutrients uptake averaged $141.7{\pm}119.2$ nmol N $g_{fw}^{-1}\;h^{-1}$ and $15.0{\pm}9.1$ nmol P $g_{fw}^{-1}\;h^{-1}$. A positive linear correlation ($r^2$ = 9.6) existed between the production rate of dissolved oxygen and the uptake rate of total dissolved inorganic carbon, suggesting that these two factors serve as good indicators of U. pinnatifida photosynthesis. The relationships between fresh weight and uptake rates of nutrients and $CO_2$ suggested that younger specimens (<~50 g fresh weight) are much more efficient at nutrients and $CO_2$ uptake than are specimens >50 g. The amount of carbon uptake by the total biomass of U. pinnatifida in Korea during the year of 2008 was about 0.001-0.002% of global ocean carbon uptake. Thus, more research should be focused on macroalgae-based biogeochemical cycles to evaluate the roles and contributions of macroalgae to the global carbon cycle.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.2
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• pp.93-106
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• 2011

This review has dealt with definition, size, history, and status of mesocosm, and also discussed several problems and trouble shootings related to the building of mesocosm, and finally will suggest the future directions of this scientific tool. Due to the restriction of the space, the discussion mainly focused on "the mesocosm building for the soft-bottom ecosystem". The mesocosm is defined as "medium-sized, self-sustaining, and man-controllable ecosystem". This type of studies has already initiated since 1960, but nowadays it expands to the diverse fields of science and technologies, such as toxicology, limnology, environmental sciences and engineering, and even geochemistry. As a scientific tool, the mesocosm requires following aspects; replicability, repeatability, and ecological realism or accuracy. Several technical problems have to be solved for the perfect building of mesocosm. They are known as scaling, composition of seawater/sediment, light intensity, turbulence, hydraulic residence time, and top predator. These trouble shootings are provided at the discussion in detail. In the context, I expect two promising directions in the future; 1. Objectivity based on the diverse statistical methodologies, 2. "Living ecosystem modelling" coordinated with the mathematical modelling. With these, the mesocosm will be more powerful tool for the scientists and engineers to investigate the chemical and the ecological responses to the toxic materials and global climate changes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.4
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• pp.251-256
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• 2016

The increase in carbon stock and sustainability of crop production are the main challenges in agricultural fields relevant to climate change. Methane is the most important greenhouse gas emitted from paddy fields. This study was conducted to investigate the effects of tillage and cultivation methods on methane emissions in rice production in 2014 and 2015. Different combinations of tillage and cultivation were implemented, including conventional tillage-transplanting (T-T), tillage-wet hill seeding (T-W), minimum tillage-dry seeding (MT-D), and no-tillage-dry seeding (NT-D). The amount of methane emitted was the highest in T-T treatment. In MT-D and NT-D treatments, methane emissions were significantly decreased by 77%, compared with that in T-T treatment. Conversely, the soil total carbon (STC) content was higher in MT-D and NT-D plots than in tillage plots. In both years, methane emissions were highly correlated with the dry weight of rice ($R^2=0.62{\sim}0.96$), although the cumulative emissions during the rice growing period was higher in 2014 than in 2015. T-T treatment showed the highest $R^2$ (0.93) among the four treatments. Rice grain yields did not significantly differ with the tillage and cultivation methods used. These results suggest that NT-D practice in rice production could reduce the methane emissions and increase the STC content without loss in grain yield.

• Economic and Environmental Geology
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• v.43 no.2
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• pp.197-205
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• 2010

Recently abrupt climate changes have been occurred in global and regional scales and $CO_2$ reduction technologies became an important solution for global warming. As a method of the solution shallow underground thermal energy storage (UTES) has been applied as a reliable technology in most countries developing renewable energy. The geothermal energy system using thermal source of soil, rock, and ground water in aquifer or cavern located in shallow ground is designed based on the concept of thermal energy recovery and storage. UTES technology of Korea is in early stage and consistent researches are demanded to develop environmental friendly, economical and efficient UTES systems. Aquifers in Korea are suitable for various type of ground water source heat pump system. However due to poor understanding and regulations on various UTES high efficient geothermal systems have not been developed. Therefore simple closed U-tube type geothermal heat pump systems account for more than 90% of the total geothermal system installation in Korea. To prevent becoming wide-spread of inefficient systems, UTES systems considering to the hydrogeothemal properties of the ground should be developed and installed. Also international collaboration is necessary, and continuous UTES researches can improve the efficiency of shallow geothermal systems.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.322-326
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• 2016

The distribution of floodplain vegetation is mainly affected by hydrological and hydraulic processes. In this study, we investigated changes in the vegetation distribution due to flood discharge alteration, and the relationship between the vegetation types and the flood frequency during the last ten-year period in the Cheongmi-cheon Stream. Flood discharge of the Cheongmi-cheon Stream tended to decrease from 2006 to 2016. It has greatly decreased to less than $160m^3/s$ since 2013. This resulted in the settlement of Phragmites japonica to the wide sand bar at the Cheongmi-cheon Stream, even though it had sparse vegetation before 2013. The sand bar was fully covered with P. japonica in 2016. Vegetation communities in the floodplain were classified by dominant species, i.e. the annual-hygrophytic, the perennial hygrophytic and the mesophytic communities. Analysis of the relationship between the vegetation communities and the flood frequency shows the annual hygrophytes, perennial hygrophytes and the mesophytes communities distributed in the range of under 1 year, 1-10 year and over 7 year flood inundation area, respectively. In conclusion, distribution of the floodplain vegetation is closely related with the flood discharge and frequency in the Cheongmi-cheon Stream.

• Korean Journal of Remote Sensing
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• v.27 no.4
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• pp.457-466
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• 2011

The objectives of this study are to produce level 3 type LULC map and analysis of phenological features of North Korea, ISODATA clustering of the 88scenes of MVC of MODIS NDVI in 2008 and 8scenes in 2009 was carried out. Analysis of phenological phases based mapping method was conducted, In level 2 type map, the confusion matrix was summarized and Kappa coefficient was calculated. Total of 27 typical habitat types that represent the dominant species or vegetation density that cover land surface of North Korea in 2008 were made. The total of 27 classes includes the 17 forest biotopes, 7 different croplands, 2 built up types and one water body. Dormancy phase of winter (${\sigma}^2$ = 0.348) and green up phase in spring (${\sigma}^2$ = 0.347) displays phenological dynamics when much vegetation growth changes take place. Overall accuracy is (851/955) 85.85% and Kappa coefficient is 0.84. Phenological phase based mapping method was possible to minimize classification error when analyzing the inaccessible land of North Korea.

• Journal of Korea Water Resources Association
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• v.49 no.7
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• pp.579-588
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• 2016

Changes in precipitation due to climate change is made to induce the local and intensive rainfall, it is increasing damage caused by inland inundation. Therefore, it requires a technique for predicting damage caused by flooding. In this study, in order to determine whether this flood inundated by any route when the levee was destroyed, Which can simulate the path of the flood inundation model was developed for the SIMOD (Simplified Inundation MODel). Multi Direction Method (MDM) for differential distributing the adjacent cells by using the slope and Flat-Water Assumption (FWA)-If more than one level higher in the cell adjacent to the cell level is the lowest altitude that increases the water level is equal to the adjacent cells- were applied For the evaluation of the model by setting the flooding scenarios were estimated hourly range from the target area. SIMOD model can significantly reduce simulation time because they use a simple input data of topography (DEM) and inflow flood. Since it is possible to predict results within minutes, if you can only identify inflow flood through the runoff model or levee collapse model. Therefore, it could be used to establish an evacuation plan due to flooding, such as EAP (Emergency Action Plan).

• Journal of Korea Water Resources Association
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• v.43 no.11
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• pp.995-1009
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• 2010

Accelerated soil erosion due to extreme climate change, such as increased rainfall intensity, and human-induced environmental changes, is a widely recognized problem. Existing soil erosion models are generally based on the gross erosion concept to compute annual upland soil loss in tons per acre per year. However, such models are not suitable for event-based simulations of erosion and deposition in time and space. Recent advances in computer geographic information system (GIS) technologies have allowed hydrologists to develop physically based models, and the trend in erosion prediction is towards process-based models, instead of conceptually lumped models. This study aims to propose an effective and robust distributed rainfall-sediment yield-runoff model consisting of basic element modules: a rainfall-runoff module based on the kinematic wave method for subsurface and surface flow, and a runoff-sediment yield-runoff model based on the unit stream power method. The model was tested on the Cheoncheon catchment, upstream of the Yongdam dam using hydrological data for three extreme flood events due to typhoons. The model provided acceptable simulation results with respect to both discharge and sediment discharge even though the simulated sedigraphs were underestimated, compared to observations. The spatial distribution of erosion and deposition demonstrated that eroded sediment loads were deposited in the cells along the channel network, which have a short overland flow length and a gentle local slope while the erosion rate increased as rainfall became larger. Additionally, spatially heterogeneous rainfall intensity, dependant on Thiessen polygons, led to spatially-distinct erosion and deposition patterns.