Island In South Korea Research Articles

A Report on the Accidental Introduction of Asian House Gecko (<i>Hemidactylus frenatus</i> Duméril et Bibron, 1836) into the Heuksan Island of South Korea

Recently, as trade between countries has flourished, the sale of living creatures has become more active. In this process, whether intentional or not, the introduction of non-native species is increasing as well. When non-native species are intentionally introduced, the route is evident which enables swift management. However, when accidentally introduced, the management of non-native species is difficult, because the route of the introduction is unclear. In this paper, we report a non-native species introduced into a small island in South Korea. On July 17, 2020, a gecko species was found on Heuksan Island. Based on its external traits, the gecko was identified as Hemidactylus frenatus, one of the rapidly increasing invasive species in the world. The gecko was dead in a packed box upon discovery, 88 km from the nearest port, and about 320 km from Seoul, where the package was shipped from. This case is yet another evidence of how non-native species can be introduced to other countries and even islands.

Microstructural and microchemical analysis of zircon in a syenite lithic fragment from Ulleung Island volcano, South Korea

Abstract Background The intricate textural patterns commonly observed in metamorphosed and recrystallized zircon (ZrSiO4) underscore the crucial necessity of understanding the underlying mechanisms governing their formation to ensure accurate interpretation of the chemical and isotope data they contain. This study employed a combination of microanalytical techniques, including electron backscattered diffraction (EBSD) analysis, electron microprobe (EMP) mapping, and scanning electron microscope (SEM) imaging, to investigate the processes of formation and modification of zircon in a late Pleistocene (~ 35 ka) syenite enclosed within the Nari Tephra Formation on Ulleung Island in South Korea. Findings Under cathodoluminescence (CL), zircons within the syenite reveal dark, featureless, or oscillatory-zoned cores containing numerous inclusions of britholite. These cores are partially or entirely replaced by inward-penetrating bright-CL domains that exhibit minimal inclusion presence. Despite these changes, the external morphologies of the zircons remain largely unchanged, and the faded oscillatory zoning is preserved in the replaced regions. EMP mapping discloses amoebiform micro-domains with high Y, U, and Th concentrations within the dark-CL cores, while the bright-CL domains are relatively deficient in these trace elements. Microstructural analysis of the zircons using EBSD mapping indicates no significant misorientation between the dark-CL cores and the bright-CL rims. Deformation-related low-angle boundaries by lattice distortion are clearly observed in certain grains, cutting across the discrete SEM and EMP domains, and often aligned along submicron pore trails. Conclusions Microstructural and microchemical analyses carried out in this study establish that the zircons within the Ulleung syenite have undergone subsolidus recrystallization, a process likely influenced by the presence of fresh melts or fluids. This recrystallization process could be attributed to either coupled dissolution and reprecipitation or thermoactivated particle and defect volume diffusion due to inherent lattice strain. The subsequent deformation observed in the zircons might be a result of increased stress within the magma system after the recrystallization.

An integrated ecosystem service-based approach for the sustainable management of forested islands in South Korea

Implementing sustainable island forest management policies requires categorizing the islands into groups based on key indicators and establishing a consistent management system. This study proposes a novel framework to support an ecosystem service-based approach to managing forested islands in South Korea. First, a typology of six forested island categories is established based on varying extents of natural vegetation cover (as a percentage of forest cover) and connectivity to the mainland. An analytic hierarchy process (AHP) analysis was conducted with island forest experts to identify priority ecosystem services (ESs) for the sustainable management of each island type. On connected islands, provisioning services (natural resources and natural medicines) are more important than regulatory (erosion control) or supporting services (genetic diversity). On unconnected islands, particularly those with a small proportion of natural vegetation, regulatory services (erosion control) require a greater emphasis on management. Since Type 3 islands require urgent management as connectivity to the mainland makes natural vegetation=sparse island forest ecosystems vulnerable to anthropogenic activities, the land-use scoring method was performed on Jin-do. Comparisons between the AHP-derived expert demand for key island ESs and the spatial distribution of ES supply potential revealed mismatches between supply and demand for erosion control, freshwater supply and habitat provision. The framework developed in this study can help guide policy and decision-making processes and indicate where interventions should be focused to achieve sustainable island management.

Quantitative analysis of fucose in fucoidans from Sargassum spp. in Jeju Island, South Korea using 3-methyl-1-phenyl-5-pyrazolone derivatization and RP-HPLC-UV method

Sargassum species are representative brown algae found worldwide, with 27 species native to the coast of Jeju Island in South Korea. Fucoidans are derived from brown algae and exhibit a variety of biological activities. Analysis of the monosaccharide composition is necessary for an in-depth study of fucoidans. However, quantitative analysis of fucoidans with complex structures according to species and habitat is insufficient. Furthermore, complex pre-processing is often required to analyze sugars, making it less economical. This study aimed to validate high-performance liquid chromatography (HPLC)-UV analysis based on 3-methyl-1-phenyl-5-pyrazolone (PMP) derivatization of monosaccharides. The proposed method had a short running time and could be repeated economically using UV detection. The detected PMP-fucose was confirmed to be uninterfered by comparing the analytical chromatograms of the internal standard solution. This analytical method was characterized for system suitability, precision, accuracy, linearity, limit of detection (LOD), and limit of quantification (LOQ), demonstrating satisfactory results. The quantification was verified by comparison with the quantitative results of commercial fucoidan obtained using high-performance anion-exchange chromatography (HPAEC) coupled with pulsed amperometric detection (PAD). Furthermore, the antioxidant effects of algal polysaccharides from Sargassum spp. isolated on Jeju Island was evaluated using a zebrafish model. Polysaccharides from Sargassum coreanum (SCpol) and Sargassum autumnale (SApol) showed remarkable free radical scavenging activities. In addition to the results obtained in the zebrafish experiments, all species-derived polysaccharides showed antioxidant potential. In conclusion, this study demonstrates a useful analytical method using HPLC-UV and PMP derivatives for the effective determination of monosaccharide contents, including fucose, in Sargassum spp.

The Association Between Short Sleep Duration and Depressive Symptoms Among Elderly Farmers

Objectives: This study was conducted to identify the association between short sleep duration and depressive symptoms among elderly farmers.Methods: This study analyzed the Safety for Agricultural Injuries of Farmers cohort data collected from September 2015 to June 2018. The data were based on an agricultural survey of the health and behaviors of adult farmers on Jeju Island in South Korea. Depressive symptoms were defined as a score of 8 or higher according to the short form of the geriatric depression scale. Short sleep duration was defined as less than 6 hours of average daily sleep duration.Results: The analysis included 507 participants, aged over 60 years. Of these, 87 (17.2%) demonstrated depressive symptoms. The prevalence of depressive symptoms differed significantly between farmers with <6 h (25.8%) and those with ≥6 h (13.5%) of sleep (<i>p</i>=0.001). Multivariable analyses confirmed that short sleep duration was significantly associated with depressive symptoms (odds ratio=1.876, 95% confidence interval=1.129–3.118).Conclusions: Our findings suggest that short sleep duration increases the risk of depressive symptoms among elderly farmers. Adequate daily sleep duration may prevent depressive symptoms in the population.

Proposed optimized energy plan for the largest island of South Korea based on full renewable energy resources

The current study's objective is to evaluate wind and solar energy and select the finest kind of energy systems having minimum levelized of energy systems by using Home Pro software for Jeju Island, the largest island in South Korea. Using Weibull and mean wind speed diagrams, the wind conditions in the initial section of this study are explained. To assess the wind potential of every area, size and form criteria are offered. It was found that two main wind directions were southeast or southwest, with southwest being more common. Finally, based on the wind conditions at each site and IEC recommendations, a set of five wind turbines that were best suited for each location were shortlisted. Each wind turbine's performance was assessed using technical criteria, that is, monthly energy production, annual energy production, and capacity factors. Similar to this, economic considerations such as the levelized cost of electricity, internal rate of return, payback period, and net present value were also made. A Hanjin model HJWT 87/2000 is best suitable for Jeju Island in the event of an off-shore wind farm, according to the findings. To explore the implications of modifying the hub height of the turbines on the economics of wind generating, a thorough economic sensitivity analysis is also included. The second section explains the solar potential of the Island. The average solar energy potential of Jeju Island is estimated to be 13.775 Mj·m2·day−1. To cover the energy demand and supply gap for Jaju Island, various types of local electricity generators and batteries have been studied for finding the optimal energy system for the island.

Genomic potential and physiological characteristics of C1 metabolism in novel acetogenic bacteria.

Acetogenic bacteria can utilize C1 compounds, such as carbon monoxide (CO), formate, and methanol, via the Wood-Ljungdahl pathway (WLP) to produce biofuels and biochemicals. Two novel acetogenic bacteria of the family Eubacteriaceae ES2 and ES3 were isolated from Eulsukdo, a delta island in South Korea. We conducted whole genome sequencing of the ES strains and comparative genome analysis on the core clusters of WLP with Acetobacterium woodii DSM1030T and Eubacterium limosum ATCC8486T. The methyl-branch cluster included a formate transporter and duplicates or triplicates copies of the fhs gene, which encodes formyl-tetrahydrofolate synthetase. The formate dehydrogenase cluster did not include the hydrogenase gene, which might be replaced by a functional complex with a separate electron bifurcating hydrogenase (HytABCDE). Additionally, duplicated copies of the acsB gene, encoding acetyl-CoA synthase, are located within or close to the carbonyl-branch cluster. The serum bottle culture showed that ES strains can utilize a diverse range of C1 compounds, including CO, formate, and methanol, as well as CO2. Notably, ES2 exhibited remarkable resistance to high concentrations of C1 substrates, such as 100% CO (200 kPa), 700 mM formate, and 500 mM methanol. Moreover, ES2 demonstrated remarkable growth rates under 50% CO (0.45 h-1) and 200 mM formate (0.34 h-1). These growth rates are comparable to or surpassing those previously reported in other acetogenic bacteria. Our study introduces novel acetogenic ES strains and describes their genetic and physiological characteristics, which can be utilized in C1-based biomanufacturing.

Landscape and Marine Environmental Factors Jointly Regulate the Intertidal Species Richness and Community Structure in the Islands of South Korea

Most studies on island biogeography have focused on the terrestrial taxa; however, there are few studies on the drivers of diversity and community structure of intertidal organisms on islands. We evaluated the effect of landscape and marine environmental factors on the species richness (SR), functional diversity (FD), and community structure (SES.MFD) of intertidal invertebrates among the overall, inhabited, and uninhabited islands. Using the data on the intertidal organisms from 78 islands in South Korea, we implemented variable selection and piecewise structural equation modeling to determine the causal relationships between the SR, FD, and SES.MFD with four landscapes (i.e., island area, coastline length, distance from the mainland, and structural connectivity) and three marine environment factors (i.e., mean annual sea surface temperature variation, wind speed, and evapotranspiration). The coastline length had a positive effect on the SR and SES.MFD in the overall islands including inhabited and uninhabited islands. The SR and FD were negatively affected by the variation in sea surface temperature. The relative importance of the landscape and marine environmental factors differed between the inhabited and uninhabited islands. That is, the inhabited islands were mainly affected by the coastline length, whereas uninhabited islands were regulated by marine environmental factors. Our results demonstrated that the biotic factors of the island intertidal ecosystems are controlled by the interactions between the biotic and various environmental factors. Moreover, the results emphasize that the water stress on the intertidal organisms due to climate change may lead to a loss of biodiversity and functional clustering.

Revealing the impact of renewable uncertainty on grid-assisted power-to-X: A data-driven reliability-based design optimization approach

Designing a reliable power-to-X (PtX) process that uses renewable energy and grid electricity as backup power is challenging due to the uncertain nature of renewables and potential limits on grid usage. To address this challenge, this paper proposes a data-driven, reliability-based optimization approach for designing a grid-assisted PtX process and understanding how the uncertainty of time-series renewable profile affects its design and optimal sizing. This approach uses generative adversarial networks (GANs) to capture the complex patterns of renewables in temporal and spatial dimensions, rather than simply treating uncertainty as a probabilistic range as in conventional methods. The optimization considers both the mean and variance of production cost as objectives, while also taking into account the level of grid energy penetration as a probabilistic constraint through the reliability analysis. A power allocation and performance evaluation model is developed and used in conjunction with the optimization to assess uncertainty propagation through the PtX process and evaluate the impact of renewable uncertainty on process performance. A case study involving the production of methanol on Jeju Island in South Korea demonstrates how the mean and variance of production cost and other performance indicators can be balanced in the reliable design of PtX processes under renewable energy uncertainty, providing insights for decision-making in such situations.

Bronchitis, COPD, and pneumonia after viral endemic of patients with leprosy on Sorok Island in South Korea

Viral respiratory diseases (VRDs) cause lung inflammation and inflammatory cytokine production. We study whether dapsone is responsible for its observed preventive treatment effects of the sustained viral RNA interferon response. Around 2008 and 2012, Korea’s Dementia Management Act stipulated drastic changes in the administration of dementia medication by medical staff. Participants were randomized and we compared leprosy patients with VRDs after prescribing dapsone as a standard treatment from 2005 to 2019. Significance was evaluated based on the dapsone-prescribed (+) subgroup and the dapsone-unprescribed (−) subgroup of the VRD diagnosed (+) and VRD undiagnosed (−) subgroup. We analyzed VRD ( +)/(− with dapsone (+)/(−) group and used a T-test, and designed the equation of acetylation with dapsone and acetylcholine (AA) equation. The 6394 VRD participants who received the dapsone intervention compared to the 3255 VRD participants in the control group demonstrated at T2 VRD (+) dapsone (−) (mean (M) = 224.80, SD = 97.50): T3 VRD (−) dapsone (+) (M = 110.87, SD = 103.80), proving that VRD is low when dapsone is taken and high when it is not taken. The t value is 3.10, and the p value is 0.004395 (significant at p < 0.05). After an increase in VRDs peaked in 2009, bronchitis, COPD, and pneumonia surged in 2013. The AA equation was strongly negatively correlated with the prevalence of bronchitis and chronic obstructive pulmonary disease (COPD): with bronchitis, r(15) = −0.823189, p = 0.005519, and with COPD, r(15) = −0.8161, p = 0.000207 (significant at p < 0.05). Dapsone treated both bronchitis and COPD. This study provides theoretical clinical data to limit acetylcholine excess during the VRD pandemic for bronchitis, COPD, and pneumonia.

Economic Analysis of P2G Green Hydrogen Generated by Existing Wind Turbines on Jeju Island

Every wind turbine is subject to fluctuations in power generation, depending on climatic conditions. When electricity supply exceeds demand, wind turbines are forced to implement curtailment, causing a reduction in generation efficiency and commercial loss to turbine owners. Since the frequency and amount of curtailment of wind turbines increases as the amount of renewable energy become higher on Jeju Island in South Korea, Jeju is configuring a Power to Gas (P2G) water-electrolysis system that will be connected to an existing wind farm to use the “wasted energy”. In this study, economic analysis was performed by calculating the production cost of green hydrogen, and sensitivity analysis evaluated the variance in hydrogen cost, depending on several influential factors. Approaches to lower hydrogen costs are necessary for the following reasons. The operating company needs a periodical update of hydrogen sale prices by reflecting a change in the system margin price (SMP) with the highest sensitivity to hydrogen cost. Technical development to reduce hydrogen costs in order to reduce power consumption for producing hydrogen and a decrease in annual reduction rate for the efficiency of water electrolysis is recommended. Discussions and research regarding government policy can be followed to lower the hydrogen cost.

Environmental Factors Associated with the Eukaryotic Microbial Diversity of Ulleungdo Volcanic Island in South Korea

Environmental Factors Associated with the Eukaryotic Microbial Diversity of Ulleungdo Volcanic Island in South Korea

The way to the ‘comedy of commons’ of a new business model-finding from Naples in Italy, and Jeju Island in South Korea

ABSTRACT In this study, we seek to examine the success factors of the classical common goods of various capitalist economies and to apply them to diverse platforms that appear as new common goods. Our research question is as follows: Are there any common success factors that can be applied to produce and use common goods across economic conditions? With the goal of identifying the grounded theory of common goods, the study employed the interview method using a semi-structured questionnaire. Furthermore, it conducted participatory observation and a literature review of case studies as well as a comparative study of 20 Korean commons and 20 Italy commons. According to cases of common goods in Jeju, South Korea, the coupling effects of several public policies could motivate the privatization of common goods. Second, an empty area in common goods consists of a high level of participation with democratization and a low level of common condition. High participation with democratization can avoid privatization and increase new open business models of common goods. Third, active open innovation with a high participation in democratization and expansion of new business models based on tacit knowledge of common goods could be the activating engine of regional innovation systems.

Volunteer tourists’ environmentally friendly behavior and support for sustainable tourism development using Value-Belief-Norm theory: Moderating role of altruism

Jeju Island in South Korea is a popular tourism destination designated as a biosphere reserve by the Natural Sciences Sector of UNESCO. However, a rapid influx of tourists into the island has caused major environmental problems, which may be reduced through volunteer tourism. This study predicts volunteer tourists' support for sustainable tourism development by applying the Value-Belief-Norm (VBN) theory and the concept of altruism. The study collected 308 responses from volunteer tourists who participated in an environmental program called Clean Olle. The findings confirmed the relationships between tourists' values, beliefs, and personal norms that predicted environmentally friendly behavior and support for sustainable tourism. Altruism, an important motivation for volunteering, reinforced tourists' environmentally friendly behavior. The study contributes to better understanding the volunteer tourists' role in sustainable tourism development and provides suggestions for destination management organizations (DMOs) in developing volunteer programs that motivate tourists’ altruism to engage in environmentally friendly behavior.

Isolation and screening of indigenous microalgae species for domestic and livestock wastewater treatment, biodiesel production, and carbon sequestration

The use of indigenous microalgae strains for locally generated domestic (DWW) and livestock wastewater (LWW) treatment is essential for effective and economical applications. Phototrophic microalgae-based biofuel production also contributes to carbon sequestration via CO2 fixation. However, simultaneous consideration of both isolation and screening procedures for locally collected indigenous microalgae strains is not common in the literature. We aimed to isolate indigenous microalgae strains from locally collected samples on coastlines and islands in South Korea. Among five isolated strains, Chlorella sorokiniana JD1-1 was selected for DWW and LWW treatment due to its ability to grow in waste resources. This strain showed a higher specific growth rate in DWW than artificial growth medium (BG-11) with a range of 0.137-0.154d-1. During cultivation, 96.5%-97.1% of total nitrogen in DWW and 89.2% in LWW was removed. Over 99% of total phosphorus in DWW and 96.4% in LWW was also removed. Finally, isolated C. sorokiniana JD1-1 was able to fix CO2 within a range of 0.0646-0.1043g CO2 L-1d-1. These results support the domestic applications of carbon sequestration-efficient microalgae in the waste-to-energy nexus.

Surface urban heat island in South Korea's new towns with different urban planning.

A new town is strategically built within a short period compared to naturally developed cities. It is considered an appropriate study area for analyzing the urban climate problems such as surface urban heat islands (SUHIs) that is differently generated according to urban planning and development. In this study, we suggest comprehensive method for determining and comparing changes in surface UHI distribution during 1989-2048 in two new towns with different urban planning. First, a substantial increase in built-up areas was observed from 1989 (< 5%) to 2018 (> 40%) in both new towns. However, SUHI phenomenon-increasing patterns were different of about 12.25% depending on urban planning and urban morphology. Results also showed the importance of vertical and horizontal structures which can have a great influence on SUHI intensity and accordingly, the difference in SUHI distribution between two new towns was confirmed. Moreover, without effective mitigation, the built-up area in both new towns is estimated to increase to approximately 60%, and the SUHI intensity in most areas to increase by 4°C in 2048. In addition, the spread and intensification of the SUHI phenomenon are predicted to be greater due to the characteristics of the building structure and the active urban expansion. Thus, these results combined with architectural assessment models can improve the understanding of thermal environmental impacts of urbanization and provide directions for sustainable urban development and renovation.

Cost analysis of off-grid renewable hybrid power generation system on Ui Island, South Korea

Diesel engine power plants are still widely used on many remote islands in South Korea, despite their disadvantages. Aiming to solve economic and environmental pollution problems, a remote island case study was conducted on Ui Island, aiming to offer a zero-emissions solution by using renewable energy sources in an off-grid application. Power was generated from solar, wind, and hydrogen sources. Li-ion batteries and hydrogen were used as energy storage systems. In addition, PV/battery, wind/battery, PV/wind/battery, PV/battery/PEMFC, wind/battery/PEMFC, and PV/wind/battery/PEMFC systems were simulated using the HOMER software to determine the optimal sizes and techno-economic feasibility. The results show that the PV/wind/battery/PEMFC system is the best system. The configuration of the system consists of 990-kW PV panels, 700-kW wind turbines, a 1088-kWh Li-ion battery bank, 534-kW converter, 300-kW PEMWE system, 300-kg hydrogen tank, and 100-kW PEMFC system. The total NPC of the system is $5,276,069, and the LCOE is 0.366 $/kWh. • A dynamic techno-economic model is developed for renewable power plant design. • Two types of ESSs are integrated with green power plants for off-grid solutions. • The LCOE can be reduced by 16% using the proposed solution.

A Short-Term Power Output Forecasting Based on Augmented Naïve Bayes Classifiers for High Wind Power Penetrations

Renewable-power-generating resources can provide unlimited clean energy and emit at most minute amounts of air pollutants and greenhouse gases, whereas fossil fuels are contributing to environmental pollution problems and climate change. The share of global power capacity comprising renewable-power-generating resources is increasing. However, due to the variability and uncertainty of wind resources, predicting the power output of these resources remains a key problem that must be resolved to establish stable power system operation and planning. In this study, we propose an ensemble prediction model for wind-power-generating resources based on augmented naïve Bayes classifiers. To select the principal component that affects the wind power outputs from among various meteorological factors, such as temperature, wind speed, and wind direction, prediction of wind-power-generating resources was performed using multiple linear regression (MLR) and a naïve Bayes classification model based on the selected meteorological factors. We proposed applying the analogue ensemble (AnEn) algorithm and the ensemble learning technique to predict the wind power. To validate this proposed hybrid prediction model, we analyzed empirical data from the wind farm of Jeju Island in South Korea and found that the proposed model has lower error than the single prediction models.

Probabilistic power output model of wind generating resources for network congestion management

With the growing importance of renewable energy generating resources around the world, the government is working towards expanding the share of renewable energy to 20% of total power generation considering the limitation of coal-fired and nuclear generation by 2030 in South Korea. However, the growing number of wind generating resources being connected to the electrical power system presents a challenge for transmission grid planning to increase the penetration of wind power while maintaining high levels of reliability and security of the electrical power system. In this paper, we propose a probabilistic power output model of wind generating resources for network congestion management. We use the historical data from the wind farms located on Jeju Island in South Korea to fit the Weibull distribution and implement Monte Carlo simulations. The simulation results, which represent network congestion with probabilistic values, are applied to the empirically modeled power grid of Jeju Island and a steady-state security evaluation is performed. The proposed probabilistic approach will be a key role to reduce the risk of over-investment in power transmission facilities compared to the deterministic approach to develop the generation mix scenarios with high wind power penetrations.

Effects of Tip Speed Ratios on the Blade Forces of a Small H-Darrieus Wind Turbine

Lift force is an important parameter for the performance evaluation of an H-Darrieus wind turbine. The rotational direction of the streamlined force is effective on the performance of the wind turbine. In order to analyze the flow characteristics around the turbine blades in real-time, a numerical analysis using three-dimensional unsteady Reynold-averaged Navier–Stokes equations has been introduced. Experimental data were obtained from a field test facility constructed on an island in South Korea and was introduced to compare the numerical simulation results with measured data. The optimum tip speed ratio (TSR) was investigated via a multi-variable optimization approach and was determined to be 3.5 for the NACA 0015 blade profile. The turbine displays better performance with the maximum power coefficient at the optimum TSR. It is due to the delay in the flow separation from the blade surface and the relatively lower strength of the tip vortices. Furthermore, the ratio between lift and drag forces is also the highest at the optimum TSR, as most of the aerodynamic force is directly converted into lift force. For one rotation of the turbine blade at the optimum TSR, the first quarter of motion produces the highest lift as the static pressure difference is maximum at the leading edge, which helps to generate maximum lift. At a TSR less than the optimum TSR, small-lift generation is dominant, whereas at a higher TSR, large drag production is observed. Both of these lead to lower performance of the turbine. Apart from the TSR, the optimum wind angle of attack is also investigated, and the results are prepared against each TSR.