• Ocean Systems Engineering
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• v.14 no.1
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• pp.85-99
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• 2024

Ocean surface currents have an essential role in the Earth's climate system and significantly impact the marine ecosystem, weather patterns, and human activities. However, predicting ocean surface currents remains challenging due to the complexity and variability of the oceanic processes involved. This review article provides an overview of the current research status, challenges, and opportunities in the prediction of ocean surface currents. We discuss the various observational and modelling approaches used to study ocean surface currents, including satellite remote sensing, in situ measurements, and numerical models. We also highlight the major challenges facing the prediction of ocean surface currents, such as data assimilation, model-observation integration, and the representation of sub-grid scale processes. In this article, we suggest that future research should focus on developing advanced modeling techniques, such as machine learning, and the integration of multiple observational platforms to improve the accuracy and skill of ocean surface current predictions. We also emphasize the need to address the limitations of observing instruments, such as delays in receiving data, versioning errors, missing data, and undocumented data processing techniques. Improving data availability and quality will be essential for enhancing the accuracy of predictions. The future research should focus on developing methods for effective bias correction, a series of data preprocessing procedures, and utilizing combined models and xAI models to incorporate data from various sources. Advancements in predicting ocean surface currents will benefit various applications such as maritime operations, climate studies, and ecosystem management.

• Environmental and Resource Economics Review
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• v.27 no.2
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• pp.233-260
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• 2018

The West Coast is known as one of the world's three largest intertidal mudflats but the mudflat ecosystems have been constantly destroyed by various reclamation projects and industrial complexes. This study intends to estimate the economic values of major ecosystem services provided by the Seocheon intertidal flats using a choice modeling method. The benefits of the intertidal flats are categorized as four different attributes: number of migratory birds (related to biodiversity and cultural services), production of fish and shellfish (regulating services and habitats), tourism activities (cultural services), and number of fishing households in local communities (cultural services). Study results show that the general public enjoys the economic benefits of 1.777 trillion won (900 million won/hectare) as of 2015 in order to preserve 1,200ha of Seocheon mudflat. Assuming that future generations continue to enjoy these economic benefits of mudflat conservation, the annual value converted is about 64.7 billion won/year, corresponding to 53.9 million won/hectare per year. Individuals are willing to pay are expected to maintain their entire life in the 1,000 households living in the Seocheon tidal-flat fishing village, with an average of 11,000 won per person and an additional 50,000 tourist activities per year. It was estimated to have the amount of payment of 9,000 won. An individual's marginal willingness to pay was estimated to be about 11,000 won per year for supporting a total of 1,000 fishing households, 6,000 won to provide tourism activities of 50,000 visitors, and 9,000 won to provide the habitats of 90,000 migratory birds. For segmentation analysis, residents of Seocheon did not place significant values for the attributes besides migratory bird conservation. However, those of Gunsan showed relatively low margtinal willingness to pay for conservation of migratory birds and fishing villages but showed similar preferences for the maintenance of tourism activities compared to the general public. The results imply that the introduction of economic incentive system is needed to effectively manage and conserve ecosystem services of specific intertidal flats.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.4
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• pp.201-210
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• 2007

Pollution by chemical substances such as POPs, EDCs and PBTs in the ecosystem has become more complex and varied, increasing the possibility of irreversible damage to human health or the ecosystem. It is necessary to have a exposure assessment in a multi-media environment for various chemical substances is required for efficient management. This study applied MUSEM(Multi-media Simplebox-systems Environmental Model), a multimedia environmental model that can simultaneously evaluate the possibility of exposure of hundreds of chemical substances in order to efficiently manage chemical substances that can have negative impact on human health or ecological environment through environmental contamination. MUSEM executed the modeling for Japan by setting all 47 prefectures of japan as the regional area for 62 chemical substances and the rest of the territory of japan, excluding regional area, as the continental area and made the estimation of concentration among environment media in each administrative area and made the sensitivity analysis on Tokyo area. The results of simulation for chemical distribution showed that most of the target chemicals located in water region. The result of sensitivity analysis for octanol-water partition rate showed that the concentration change of soil in urban/industrial area and sediment in freshwater was high. In the case of sensitivity analysis for degradation rate showed that the concentration change of freshwater, soil in urban/industrial area, and sediment in freshwater was high.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.6
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• pp.405-412
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• 2014

A number of algal bloom models (red-tide models) have been developed and applied to simulate the redtide growth and decline patterns as the interest on the phytoplankton blooms has been continuously increased. The quantitative error analysis of the model is of great importance because the accurate prediction of the red-tide occurrence and transport pattern can be used to setup the effective mitigations and counter-measures on the coastal ecosystem, aquaculture and fisheries damages. The word "red-tide model" is widely used without any clear definitions and references. It makes the comparative evaluation of the ecological models difficult and confusable. It is highly required to do the performance test of the red-tide models based on the suitable classification and appropriate error analysis because model structures are different even though the same/similar words (e.g., red-tide, algal bloom, phytoplankton growth, ecological or ecosystem models) are used. Thus, the references on the model classification are suggested and the advantage and disadvantage of the models are also suggested. The processes and methods on the performance test (quantitative error analysis) are recommend to the practical use of the red-tide model in the coastal seas. It is suggested in each stage of the modeling procedures, such as verification, calibration, validation, and application steps. These suggested references and methods can be attributed to the effective/efficient marine policy decision and the coastal ecosystem management plan setup considering the red-tide and/or ecological models uncertainty.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.1
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• pp.38-46
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• 2012

This study carried out current status, characteristics, and problems of coastal environment management on semi-enclosed Masan Bay in Korea and suggests cost-effective and eco-friendly water quality management policy. The pollutants from terrestrial sources into the Bay have apparently environmental pollution problems, such as eutrophication, red tide, and hypoxia. The carrying capacity of the Bay is estimated by hydrodynamic model and ecosystem model, material circulation including bivalve in ecosystem is analyzed by the growth model of bivalve. The resulting reduction in the input load was found to be 50~90%, which is unrealistic. When the efficiency of water quality improvement through bivalve farming was assessed based on the autochthonous COD, 30.7% of the total COD was allochthonous COD and 69.3% was autochthonous COD. The overall autochthonous COD reduction rate by bivalve aquaculture farm was found to be about 6.7%. This study indicate that bivalve farming is about 31% less expensive than advanced treatment facilities that remove both nitrogen and phosphorous.

• Economic and Environmental Geology
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• v.48 no.6
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• pp.477-490
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• 2015

In this study, we investigated the restoration possibility of the old streams by enhancing the rainwater infiltration in the watershed of Deokjin Park, Jeonju City. This study was performed by modeling groundwater discharge to the streams under various conditions. We assessed the amount and location of groundwater recharge enhancement to restore the streams and evaluated whether the baseflows of the restored streams are sufficient to keep the water ecosystem of the Deokjin Pond. The results show that the baseflow of the streams can persist for a longer time even during the dry season when the rainwater drainage system is recovered similarly to the those before development using low impact development (LID) techniques. The enhancements of recharge in the headwater area, which is the area around the zoo and Daeji Village in the Deokjin Park watershed, is useful to increase the baseflows of the downstream reaches. Furthermore, spreaded recharge over a widespread area is better to prevent the streams from drying than the intensive recharge at a few sites.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.94-106
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• 2008

As populations inhabiting in natural ecosystem are fragmented by artificial barriers and habitats are destructed by development, extinction possibility of species is getting higher. It is necessary to design and to manage conservation areas and corridors considering animals' movement and migration for sustainable species diversity in present circumstances. 'Least-cost modeling' is one commonly employed approach in which dispersal costs are assigned to distinct habitat types and the last-costly dispersal paths among habitat patches are calculated using a geographical information system (GIS). This study aims to design ecological corridor using least-cost path method and to apply it to a regional ecological network considering movability of medium-large size mammals. This study was carried out over the metropolitan area, which has been deforested by rapid urbanization. Nevertheless there is connected with Gangwon province, Baekdudaegan mountain range and DMZ, considered where many forest species can migrate to this region. This study employs such an approach to develop least-cost path models for medium-large size mammals, have inhabited for this entire region. Considering those species, two forest areas as a source of species supply and forest areas more than 1,000ha are selected as focal forest areas. Movement and migration paths from species supply sources to focal forest areas are calculated by applying landscape permeability theory using land cover map, road density map and land slope map. Results showed least-cost paths from species supply sources to focal forest areas on two species. Wildcat and roe deer are different in some least-cost paths caused by their landscape permeability but paths show generally same specifics. The result of considering regional distribution of expected movement and migration paths to regional ecological network, low altitude mountains of western metropolitan area are evaluated important area for species connectivity. In national or regional levels ecological connectivity is essential to promote species diversity and to preserve integrated ecosystem. This study concludes that developing least-cost models from similar empirical data could significantly improve the utility of these tools.

• Korean Journal of Construction Engineering and Management
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• v.19 no.4
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• pp.93-101
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• 2018

A city is like a living organism that is born, grows and become extinct within an ecosystem. In recent years, more and more cities have been planned by designers rather than spontaneously growing over time. This planning means that if a city is not appropriately designed at the beginning, it is very hard to fix or adjust it later. A poor urban design inconveniences many people, and forces them to adjust to it. For this reason, it is important to design a city as optimally as possible at the design phase. One of the reasons why a city is not designed optimally is complexity. Previous urban design methods have attempted to resolve the complexity by using a top-down problem-solving method based on the experience and knowledge of the urban planner. However, such an approach does not have the organic characteristics of a bottom-up problem-solving method of an artificial life, based on the creation principle of the ecosystem. Therefore, in this study the general principle of artificial life, which can provide a solution to the bigger problems that accumulate as a result of the solutions to small units of problems, is adopted. This enables us to draw various urban design alternatives, and it proves that the alternatives, despite being drawn through a limited modeling method, have almost no differences from those designed by an expert, and its possibilities of future development has also been verified.

• Ecology and Resilient Infrastructure
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• v.10 no.4
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• pp.161-170
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• 2023

We attempted to estimate the carbon accumulation of Hibiscus hamabo and Paliurus ramosissimus, semimangroves native to Jeju Island, by remote sensing and to build an artificial intelligence model that predicts its spatial variation with climatic factors. The aboveground carbon accumulation of semi-mangroves was estimated from the aboveground biomass density (AGBD) provided by the Global Ecosystem Dynamics Investigation (GEDI) lidar upscaled using the normalized difference vegetation index (NDVI) extracted from Sentinel-2 images. In Jeju Island, carbon accumulation per unit area was 16.6 t C/ha for H. hamabo and 21.1 t C/ha for P. ramosissimus. Total carbon accumulation of semi-mangroves was estimated at 11.5 t C on the entire coast of Jeju Island. Random forest analysis was applied to predict carbon accumulation in semi-mangroves according to environmental factors. The deviation of aboveground biomass compared to the distribution area of semi-mangrove forests in Jeju Island was calculated to analyze spatial variation of biomass. The main environmental factors affecting this deviation were the precipitation of the wettest month, the maximum temperature of the warmest month, isothermality, and the mean temperature of the wettest quarter. The carbon accumulation of semi-mangroves predicted by random forest analysis in Jeju Island showed spatial variation in the range of 12.0 t C/ha - 27.6 t C/ha. The remote sensing estimation method and the artificial intelligence prediction method of carbon accumulation in this study can be used as basic data and techniques needed for the conservation and creation of mangroves as carbon sink on the Korean Peninsula.

• Journal of Forest and Environmental Science
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• v.30 no.4
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• pp.351-361
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• 2014

Leaf area ($A_0$) and leaf biomass ($M_0$) estimation are significant prerequisites to studying tree physiological processes and modeling in the forest ecosystem. The objective of this study was to develop allometric models for estimating $A_0$ and $M_0$ of Swietenia mahagoni L. from different tree parameters such as DBH and tree height of mahogany plantations in the northeastern region of Bangladesh. A total of 850 healthy and well formed trees were selected randomly for sampling in the five study sites. Then, twenty two models were developed based on different statistical criteria that propose reliable and accurate models for estimating the $A_0$ and $M_0$ using non-destructive measurements. The results exposed that model iv and xv were selected on a single predictor of DBH and showed more statistically accuracy than other models. The selected models were also validated with an additional test data set on the basis of linear regression and t-test for mean difference between observed and predicted values. After that, a comparison between the best logarithmic and non-linear allometric model shows that the non-linear model produces systematic biases and underestimates $A_0$ and $M_0$ for larger trees. As a result, it showed that the bias-corrected logarithmic model iv and xv can be used to help quantify forest structure and functions, particularly valuable in future research for estimating $A_0$ and $M_0$ of S. mahagoni in this region.