Jeju Island Research Articles

Neuroimaging Characteristics of Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) in Korean Based on Jeju Cohort: A Pictorial Essay

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary small artery vasculopathy caused by mutations in the NOTCH3 gene on chromosome 19. Jeju Island has the highest reported prevalence of CADASIL patients in the world. Even though most studies on the neuroimaging characteristics of CADASIL have focused on Western populations, there are notable differences in Korean CADASIL patients compared to those in Western countries, which may impact their clinical manifestations and prognosis. Herein, this pictorial essay presents the neuroimaging patterns of CADASIL in patients in Korea, with an emphasis on the differences observed from previous reports based on a Western patient population.

Coinfection of Severe Fever With Thrombocytopenia Syndrome Virus and Coxiella burnetii in Developmental Stage of Hard Ticks in Subtropical Region of Korea.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is transmitted through tick bites. Ticks are potential vectors for the bacterium Coxiella burnetii that causes Query fever. Here, we analyzed SFTSV and C. burnetii co-infection rates in ticks in rural areas of Jeju Island, South Korea. Free ticks were collected from the natural environment of the island between 2016 and 2019, and SFTSV RNA was extracted. Additionally, ribosomal RNA gene sequencing was used to identify Coxiella species. Haemaphysalis longicornis was the most common tick species followed by H. flava. Tick number gradually increased from April, peaked in August, and was lowest in March. Of all the collected ticks, 82.6% (2,851/3,458) were nymphs, 17.9% (639/3,458) adults, and 0.1% (4/3,458) larvae. SFTSV-infected ticks comprised 12.6% of all ticks; their numbers were the lowest in November-December, increased from January, and were mostly identified in the adult stage during June-August. C. burnetii infections were detected in 4.4% of the SFTSV-infected H. longicornis ticks. C. burnetii co-infection was mainly observed in the nymph stage of H. longicornis, with the highest infection rate in January, followed by December and November. Our findings suggest that Jeju Island has a high SFTSV and potential C. burnetii infection in ticks. This study provides important insights regarding SFTS and Q fever risk to humans in South Korea.

Impact on Platooning of Autonomous Vehicles using Macro to Micro simulations

Social costs increase as traffic problems continue. Driverless vehicles are attracting attention as a way to overcome this issue. Many said that fully autonomous driving is not a distant future. As one of the autonomous vehicle operations, vehicle platooning has been paid attention. Therefore, this study analyzes the effects of vehicle platooning on the road network. As a large-scale network, Jeju island, one of the cities in Korea was selected to test the platooning arrangement. A macro simulation was developed and calibrated based on the collected traffic counts, and then the network and assigned paths were imported to the micro simulation, which is capable of forming the platoon. The analysis was conducted by changing various parameters of the platooning vehicle. According to the investigation, it can be seen that as the market share of autonomous vehicles increases, delays decrease, and speed increases. Traffic efficiency was improved through platooning in general. It is expected that the results of this study can be used as primary data to develop an optimal traffic flow management strategy for cluster operation.

An Effect of Wind Veer on Wind Turbine Performance

An investigation was performed to identify the wind veer impact on wind turbine power performance at a wind farm located on Jeju Island, South Korea. A 2 MW wind turbine was used as a test turbine. An 80 m-tall met mast was located 220 m away from the test wind turbine and a ground lidar was installed close to the met mast. The wind veer conditions were divided into four types: veering in upper and lower rotor (VV), veering in upper and backing in lower rotor (VB), backing in upper and lower rotor (BB) and backing in upper and veering in lower rotor (BV). The frequency of the four types was identified at the wind farm. The characteristics of wind veer was analysed in terms of diurnal variation and wind speed. In addition, the power curves of the four types were compared with that under no veer condition. Also, the power deviation coefficient (PDC) derived from the power outputs was calculated to identify the effect of the four types on the turbine power performance. As a result, the frequencies of the types, VV, VB, BB and BV were 62.7 %, 4.9 %, 9.2 % and 23.1 %, respectively. The PDCs for the types VV and BV were 3.0 % and 4.2 %, respectively, meaning a power gain while those for the types VB and BB were -2.9 % and -3.9 %, respectively, meaning a power loss.

Discovery of a New Sea Spider Belonging to the Genus Pycnogonum (Pycnogonida: Pycnogonidae) in the Mesophotic Zone of Jejudo Island, Korea.

A new species of the genus Pycnogonum was discovered in the mesophotic zone of Munseom Islet, Jejudo Island, Korea. Pycnogonum (Nulloviger) bifurcatum sp. nov. is the first case of sea spiders in Korean fauna not only included in the subgenus Nulloviger but also collected in the mesophotic zone of Munseom Islet. The new species is morphologically close to Pycnogonum (Pycnogonum) asiaticum and P. (N.) carinatum, sharing the granular integument, the dorsomedian tubercles on the trunk, and the post-ocular tubercle. The new species can be easily distinguished from the congeners by combination of the following characteristics: the prominent dorsomedian tubercles on the trunk, the lateral processes 1-3 touching each other, and the small auxiliary claws. A key is provided to distinguish 12 species of the subgenus Nulloviger morphologically, and molecular data of the new species are provided for species identification and further studies.

Extensive characterization of 28 complete chloroplast genomes of Hydrangea species: A perspective view of their organization and phylogenetic and evolutionary relationships

The tribe Hydrangeeae displays a unique, distinctive disjunct distribution encompassing East Asia, North America and Hawaii. Despite its complex trait variations and polyphyletic nature, comprehensive phylogenomic and biogeographical studies on this tribe have been lacking. To address this gap, we sequenced and characterized 28 plastomes of Hydrangeeae. Our study highlights the highly conserved nature of Hydrangeaceae chloroplast (cp) genomes in terms of gene content and arrangement. Notably, synapomorphic characteristics of tandem repeats in the conserved domain of accD were observed in the Macrophyllae, Chinenses, and Dichroa sections within the Hydrangeeae tribe. Additionally, we found lower expression of accD in these sections using structure prediction and quantitative real-time PCR analysis. Phylogenomic analyses revealed the subdivision of the Hydrangeeae tribe into two clades with robust support values. Consistent with polyphyletic relationships, sect. Broussaisia was identified as the basal group in the tribe Hydrangeeae. Our study also provides insights into the phylogenetic relationships of Hydrangea petiolaris in the Jeju and Ulleung Island populations, suggesting the need for further studies with more samples and molecular data. Divergence time estimation and biogeographical analyses suggested that the common ancestors of the tribe Hydrangeeae likely originated from North America and East Asia during the Paleocene period via the Bering Land Bridge, potentially facilitating migration within the tribe between these regions. In conclusion, this study enhances our understanding of the evolutionary history and biogeography of the tribe Hydrangeeae, shedding light on the dispersal patterns and origins of this intriguing plant group with its unique disjunct distribution.

Monitoring of Microplastics and Styrene Oligomers in the Atmosphere

Objectives:Plastic pollution is a very important environmental issue. The objective of this study is to monitor microplastics and styrene oligomers (SOs) as artificial chemical species that can be derived from polystyrene (PS) plastics. Methods:In order to achieve the above objective, this study collected atmospheric samples from the air of Gwangju City and Jeju Island and analyzed the concentrations of microplastics and SOs chemical species using Fourier transformed infrared spectroscopy (FTIR) and gas chromatography/mass spectroscopy (GC/MS). In this study, a stainless steel filter was used for the sampling of microplastics and SOs species.Results and Discussion:In 2019, the average concentration of SOs in the atmosphere of Gwangju City was 0.24 (± 0.56) µg/m<sup>3</sup>, and in 2020, the average concentration of SOs in Gwangju City was 0.10 (± 0.16)µg/m<sup>3</sup>. Those average concentration in Jeju Island in 2020 was monitored to be 0.11 (± 0.07) µg/m<sup>3</sup>. Moreover, the concentration of microplastics present in the atmosphere of Gwangju City and Jeju Island in 2020 ranged from 0.13 particles/m<sup>3</sup> to 1.13 particles/m<sup>3</sup>. In this time, 9 types of microplastics were detected, and the most frequently detected microplastics were polyethylene (PE), polypropylene (PP), ethylene vinyl acetate (EVA), and acrylate materials. The monitored microplastic shapes were both fibers and fragments, suggesting that atmospheric microplastics are mainly released from fibers or caused by friction and breakage. Consequently, SOs and microplastics can be new pollution indicators for evaluating air quality. Conclusion:This study is the first attempt to monitor SOs compounds and microplastics, so it is expected to contribute to the evaluation of the extent of plastic pollution.

조선총독부의 민족종교 탄압과 제주도 무극대도 사건

The Mugeuk Daedokyo Incident on Jeju Island was a significant incident that occurred on Jeju Island in 1937 when Japan was moving toward militarism. According to the verdict, 20 people were convicted in this case. The most common crimes they were charged with were “impiety to the Japanese Emperor” and “National security law.” ‘Impiety to the Japanese Emperor” consisted in the fact that they foresaw that the Japanese Emperor would soon be dethroned, and “National security law” was invoked as they said that Japan’s imperialism would soon collapse and Joseon would become independent. Additionally, Military penal law and Navy penal law were involved as Japan said that it would lose in the Sino-Japanese War. This incident was part of an independence movement that desired the defeat of Japan and Korea's independence. To block the support of the general public for the religious leader Kang Seung-tae, the Japanese government played on social issues such as “fraud,” “rape,” and “violation of doctors’ rules.” charged with immorality.
 The Imperial Japanese divided the religions of colonial Korea into two types. Japan’s state religions, “Shinto” and “Buddhism,” and “Christianity,” were classified as religions and administered by the Religious Division of the Academic Affairs Bureau of the Japanese Government-General of Korea. Ethnic religions that desired human liberation, national liberation, and national independence were classified as “similar religions,” and were controlled by the Government-General’s Police Bureau, which suppressed independence activists. Religions classified as pseudo-religions were all ethnic religions that dreamed of national liberation.
 Even after the liberation of Korea, this religious classification made by the Japanese was accepted as it was, and those involved in the Mugeukdaedo incident were excluded from the national conferment of a decoration. Kang Seung-tae, the leader of the Mugeuk Daedokyo, was treated as a person of interest to the point that even after serving his six-year sentence, the Japanese Empire would not release him, because the view of the Japanese Government- General, who treated him as a pseudo religious leader, was maintained even after liberation.
 Now is the time to frame the Mugeukdaedo incident on Jeju Island as one of the fiercest national liberation movements of the 1930s.

신품종 적색종 용과의 인공수분 시간대 및 착과량에 따른 수량 비교

Jeju Island is changing from temperate to subtropical climate. The demand for tropical fruits has increased significantly during the past decades as consumers seek healthy and more diverse food products. The cactacease family of Dragon fruit(Hylocereus spp.) knowns as pitaya, includes 18 species that originated in Mexico and Central and South America. Dragon fruit has been reported not only for its nutritive and medical value such as beta-carotene, lycopene, and vitamin E, but also other antioxidants which enhance for immune system. These flowers are large that usually open at night and close early in the morning, so artificial pollination through bats and bees or hand pollination can enhance the fruit quality. If pollination is missed during flower bloom, the characteristics such as fruit weight, length, diameter, total soluble solids contents(TSS, °brix), and acidity decrease. In order to stably maintain the appropriate fruit qualities it is necessary to set the pollinate time point and fruit number per cladodes. This study was conducted to investigate suitable artificial pollinate time point and fruit number per cladodes in order to the development of cultivation method. There were no differences in fruit set, quantity, and fruit characteristics in hand pollination in the morning and afternoon. Greenhouses in Jeju Island, where dragon fruits are grown, do not have night lights installed, so they prefer to hand-pollinate in the morning. Cladodes with 1 to 3 fruits were randomly selected and investigated in order to establish the optimal number of fruits per cladode and to cultivate them stably. There were no statistical differences in fruit set, fruit weight, length, diameter, TSS, acidity among fruit number per fruit cladodes. Also, there were no significant differences in the daily changes in fruit length and diameter during fruit development and maturation. The fruit length and diameter daily change was highest until the 12th day of anthesis and decreased with time. The present study imply that early management during fruit growth development is important. Plants with 3 fruiting per cladode were no problem in the fruit set and fruit characteristics, but a number of floral buds (more three) could fall before anthesis depend on plant condition. Based on this study, 1-2 fruiting per cladode is most effective in setting to stable production.

지식재산 확산을 위한 제주 향토 문화 활용 지식재산 경진대회(상표, 디자인)를 통한 생물자원의 권리화 사례 연구

The 'Jeju Local Culture Utilizing Trademark and Design Contest' is held as part of disseminating intellectual property and nurturing human resources with the goal of creating a leading model for intellectual property education, the only base in the Jeju region including subtropical biological industry such as citrus. This contest has been operated since 2019 in collaboration with related organizations in Jeju Island. The purpose of the contest is to induce the creation of intellectual property through the realization of creative ideas using the local culture of Jeju Island, and to discover intellectual property talents to strengthen employment and start-up capabilities. The target audience is elementary, middle and high school students, undergraduate and graduate students, and the general public residing in Jeju Island. The fields of participation are divided into trademark and design fields using Jeju language and Jeju culture. Ideas of various age groups are being discovered and combined with local culture. The submitted works are reviewed and the best works are selected and supported so that they can be turned into rights. Through this study, we intend to review the operation cases and results of competitions utilizing local culture, and suggest best practices for nurturing intellectual property talents and securing regional-specific intellectual property rights.

<i>Saxifraga cortusifolia</i> (Saxifragaceae): A new record for the Korean flora from Jejudo Island

<i>Saxifraga cortusifolia</i> Siebold & Zucc. (Saxifragaceae, sect. <i>Irregulares</i>, ser. <i>Rufescentes</i>), a species considered endemic along mountain streams throughout Honshu, Shikoku, and Kyushu in Japan, was discovered as a wild population in the Cheona Valley in Haean-dong, Jeju-si on Jeju-do Island of Korea. The population consisted of three subpopulations occupying narrow areas 10 × 10 m<sup>2</sup>, 5 × 5 m<sup>2</sup>, and 10 × 5 m<sup>2</sup> in size. The number of individuals in the three subpopulations was confirmed to exceed 100. Most of the individuals were on or below rocks at the edge of the valley. A morphological description, detailed photos, and a key to related taxa in Korea are presented.

A Study of the relationship between the myth of two islands and traditional residence space: focusing on the myth of fire god and kitchen space in Jeju and Okinawa Island

A Study of the relationship between the myth of two islands and traditional residence space: focusing on the myth of fire god and kitchen space in Jeju and Okinawa Island - Jeju Island;Okinawa;resentment culture;kitchen god;fire god

Temporal variation in the community structure of green tide forming macroalgae (Chlorophyta; genus <i>Ulva</i>) on the coast of Jeju Island, Korea based on DNA barcoding

Temporal variation in the community structure of green tide forming macroalgae (Chlorophyta; genus <i>Ulva</i>) on the coast of Jeju Island, Korea based on DNA barcoding

Study on an advanced borehole heat exchanger for ground source heat pump operating in volcanic island: Case study of Jeju island, South Korea

This paper presents an advanced borehole heat exchanger that has been developed in order to apply a ground source heat pump to a volcanic island where the existing borehole heat exchangers are inapplicable by local ordinance. The advanced borehole heat exchanger was fabricated and installed at a verification-test site to evaluate its heat capacity in terms of refrigeration ton (RT). The proposed heat exchanger was also compared with the conventional heat exchanger that was made of high-density polyethylene (HDPE) heat exchanger. The thermal response test was carried out by flowing water at various temperatures into the heat exchangers at the fixed flow rate of 180 L/min. The results revealed that the maximum heat capacity for the developed heat exchanger was measured at 63.9 kW, which is 160% higher than that of the high-density polyethylene heat exchanger (39.9 kW). It was also found that the developed HX has the highest heat gain achieving 94 kW as compare to 21 kW for high-density polyethylene-Hx.

A Case Study on the Preliminary Study for Disaster Prevention of Storm Surge: Arrangement of Structures

Climate change is accelerating worldwide due to the recent rise in global temperature, and the intensity of typhoons is increasing due to the rise in seawater temperature around the Korean Peninsula. An increase in typhoon intensity is expected to increase not only wind damage, but also coastal damage caused by storm surge. Accordingly, in this study, a study of the method of reducing storm surges was conducted for the purpose of disaster prevention in order to respond to the increasing damage from storm surges. Storm surges caused by typhoons can be expected to be affected by structures located on the track of typhoon, and the effects of storm surges were studied by the eastern coast and the barrier island along the coast of the Gulf of Mexico in the United States. This study focused on this aspect and conducted related research, considering that storm surges in the southern coastal area of the Korean Peninsula could be directly or indirectly affected by Jeju Island, which is located on the track of typhoon. In order to analyze the impact of Jeju Island on storm surges, simulations were performed in various situations using a numerical analysis model. The results of using Jeju Island are thought to be able to be used to study new disaster prevention structures that respond to super typhoons.

Spatiotemporal overlap between Siberian roe deer (Capreolus pygargus tianschanicus) and sympatric mammalian species on Jeju Island, South Korea

Abstract Analysis of spatiotemporal partitioning is pivotal to shed light on interspecific coexistence. Most research efforts have involved large-sized carnivores and their prey species, whereas little attention has been given to ungulate in the predator-free ecosystems. We assessed seasonal activity patterns and spatiotemporal overlap among the Siberian roe deer (Capreolus pygargus tianschanicus) and its sympatric species through camera-trapping from October 2017 and September 2020 in Jeju Island, South Korea. Trap events when compared seasonally, roe deer show higher activity in summer (34.9%), a pronounced low in winter (14.1%), and a moderate in autumn (23.8%) and in spring (26.9%). Roe deer exhibited bimodal activity patterns and had the highest spatiotemporal overlap and composite score with sika deer (Cervus nippon). Our results are among the few available data on the interaction of sympatric species and suggest strong overlapping with sika deer. This study provides important insight into species coexistence in predator-free habitats, which would be important for management initiatives.

Climate Change and Tourism Sustainability in Jeju Island Landscape

The transformation of tourism as a reaction to climate change involves the adoption of a low-carbon route, which comprises policy and institution reforms, behavior changes, and climate change action as major components. Using Jeju Island in the Republic of Korea as a case study, this research highlights the potential of an organic relationship between climate change reaction and the development of sustainable tourism. The situation on Jeju Island, which is detailed in this study, highlights the link between low-carbon tourism and initiatives for mitigating climate change. This article outlines how climate action congruent with climate change and sustainable tourism may be implemented on Jeju Island. In addition, the link between climate change and sustainable tourism is studied in depth by evaluating the likelihood of the failure of a number of climate change-response programs. This approach emphasizes how the example of Jeju Island might be a small step toward addressing climate change and sustainable tourism issues in developing countries.

Independent Power Producer Approach to Optimal Design and Operation of IES with Wind Power Plants

In South Korea, Renewable Energy Sources (RES) have been increasing with the application of energy policies, such as Feed in Tariff (FIT) and the Renewable Portfolio Standard (RPS). However, a rapid increase in RES supply leads to an uncertain power supply due to the intermittent output of RES. A representative example is the curtailment of Wind Turbines (WT), which frequently occurs in Jeju Island, South Korea. The proportion of RES power on Jeju Island is 67%, and there are cases where WT is curtailed among the operable sections to maintain the balance of power supply and demand. This paper applies Power-to-Gas (P2G) technology to hydrogenate, store, and utilize unused power to solve this problem. In this paper, Aewol-eup in Jeju Island is selected as a target site for case study. An Integrated Energy System (IES) for various energy operations is designed to control RES output. This paper proposes the optimal facility configuration and finally drives the optimal design and operation solution of IES by analyzing the objective functions and focusing on the Independent Power Producer (IPP) perspective.

Generalization of U-Net Semantic Segmentation for Forest Change Detection in South Korea Using Airborne Imagery

Forest change detection is essential to prevent the secondary damage occurring by landslides causing profound results to the environment, ecosystem, and human society. The remote sensing technique is a solid candidate for identifying the spatial distribution of the forest. Even though the acquiring and processing of remote sensing images are costly and time- and labor-consuming, the development of open source data platforms relieved these burdens by providing free imagery. The open source images also accelerate the generation of algorithms with large datasets. Thus, this study evaluated the generalizability of forest change detection by using open source airborne images and the U-Net model. U-Net model is convolutional deep learning architecture to effectively extract the image features for semantic segmentation tasks. The airborne and tree annotation images of the capital area in South Korea were processed for building U-Net input, while the pre-trained U-Net structure was adopted and fine-tuned for model training. The U-Net model provided robust results of the segmentation that classified forest and non-forest regions, having pixel accuracies, F1 score, and intersection of union (IoU) of 0.99, 0.97, and 0.95, respectively. The optimal epoch and excluded ambiguous label contributed to maintaining virtuous segmentation of the forest region. In addition, this model could correct the false label images because of showing exact classification results when the training labels were incorrect. After that, by using the open map service, the well-trained U-Net model classified forest change regions of Chungcheong from 2009 to 2016, Gangwon from 2010 to 2019, Jeolla from 2008 to 2013, Gyeongsang from 2017 to 2019, and Jeju Island from 2008 to 2013. That is, the U-Net was capable of forest change detection in various regions of South Korea at different times, despite the training on the model with only the images of the capital area. Overall, this study demonstrated the generalizability of a deep learning model for accurate forest change detection.

Primary production by phytoplankton in the territorial seas of the Republic of Korea

The primary production (PP) by phytoplankton in marine ecosystems is essential for carbon cycling and fueling food webs. Hence, estimating the PP in the territorial sea of each country is a necessary step to achieving carbon neutrality. To estimate the PP in the territorial sea of the Republic of Korea from 2005 to 2021, we analyzed various physiochemical parameters, such as sea surface temperature (SST), Secchi depth, and concentrations of chlorophyll-a and nutrients in the seas of five regions, including the East Sea, West Sea, western South Sea, eastern South Sea, and the waters off Jeju Island. During the 17-year study period, the SST tended to increase, while the nutrient concentrations declined, except in the Jeju area. Overall, the PP did not show a specific temporal trend, but daily PP in the western South Sea was the highest among the five regions. Moreover, the maximum PP in the Korean territorial waters (76,450 km2 ) was estimated at 11,227 Gg C y-1, which accounts for 0.03% of the global PP. The results may give insights into a better understanding of the PP, further resource utilization, and environmental sustainability in the studied region.