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In this study, we analyzed the characteristics of the heavy rainfall events that occurred in Seoul in 2022 and compared them with the projections of the representative concentration pathway (RCP). The analysis results indicated that climate change is ongoing. In this era of climate crisis, based on the shared socioeconomic pathway (SSP) data, we projected the 20-year frequency rainfall for South Korea at intervals of 1 day/24 h. Our results indicate that the maximum rainfall (with a 24 h duration) will increase by ~18% in the second half of the 21st century, compared to the current maximum rainfall. Finally, we projected the intensity–duration–frequency (IDF) curve for the infrastructure design of Seoul. According to the projected IDF curve, across all durations, the rainfall intensity was the strongest in the early 21st century, indicating that at present, we are in the midst of a climate crisis. Thus, it is important to develop and implement effective urban and river flood management measures to mitigate the current effects of climate change. Notably, our study can serve as a reference for future studies on climate change and help policymakers and decision-makers develop relevant policies and mitigation strategies related to the effects of climate change. [ABSTRACT FROM AUTHOR]

Objective: Stimulant use instigates abstinence syndrome in humans. miRNAs are a critical component for the pathophysiology of stimulant abstinence. Here we sought to identify a miRNA marker of methamphetamine abstinence in the circulating extracellular vesicles (cEVs). Methods: miR-137 in the cEVs was quantified by qPCR in thirty-seven patients under methamphetamine abstinence and thirty-five age-matched healthy controls recruited from 2014 to 2016 from the general adult population in a hospital setting, Seoul, South Korea. Diagnostic power was evaluated by area under curve in the receiver-operating characteristics curve and other multiple statistical parameters. Results: Patients under methamphetamine abstinence exhibited a significant reduction in cEV miR-137. Overall, cEV miR-137 had high potential as a blood-based marker of methamphetamine abstinence. cEV miR-137 retained the diagnostic power irrespective of the duration of methamphetamine abstinence or methamphetamine use. Interestingly, cEV miR-137 interacted with age: Control participants displayed an aging-dependent reduction of cEV miR-137, while methamphetamine-abstinent patients showed an aging-dependent increase in cEV miR-137. Accordingly, cEV miR-137 had variable diagnostic power depending on age, in which cEV miR-137 more effectively discriminated methamphetamine abstinence in the younger population. Duration of methamphetamine use or abstinence, cigarette smoking status, depressive disorder, or antidepressant treatment did not interact with the methamphetamine abstinence-induced reduction of cEV miR-137. Conclusion: Our data collectively demonstrated that miR-137 in the circulating extracellular vesicles held high potential as a stable and accurate diagnostic marker of methamphetamine abstinence syndrome. [ABSTRACT FROM AUTHOR]

• The (Korean) Chinese neighborhood is a multilayered diasporic space. • The dominant and marginal values of the neighborhood make up different landscapes. • Commodified Chinese culture is placed in the center of the neighborhood. • The stigma of precarity is inscribed in visually marginalized places. • The different landscapes subtly signify an inclusion-exclusion dynamic. This study analyzes visual-material resources, spatial organization, and human activities taking place in a large (Korean) Chinese migrant neighborhood in Seoul, South Korea. Grounded in walking fieldwork, this study identifies how dominant and marginal values are imposed in commercial streets and their surroundings of the neighborhood. The main commercial area plays a central role in the neighborhood, appropriating commodified Chinese cultures. A large local market commodifies Chinese culture in promoting the market as a multicultural place, while many Chinese restaurants highlight Chineseness, attracting both migrant and local consumers. On the other hand, the stigma of precarity is inscribed in every corner of the long-time low-income area: signs of otherness and unstable lives in the commercial landscape signify marginalization. The values expressed by the migrant neighborhood subtly suggest how migrants have been both included and excluded in South Korean society. [ABSTRACT FROM AUTHOR]

Ambient PM2.5 samples were taken at 24-h intervals in three Korean cities from September 2002 to February 2004, and their ionic constituents were analyzed. The mean PM2.5 mass concentrations were 42.9, 42.8, and 40.8μgm−3 in Seoul, Chuncheon, and Ulsan, respectively. In Ulsan, the concentrations in the two winters (2002–2003 and 2003–2004) were statistically different each other because in 2002–2003 the airborne trajectories passed through metropolitan and industrialized areas, whereas in 2003–2004 they did not. Ionic constituents amounted to about 39, 35, and 60% of the PM2.5 masses measured in Seoul, Chuncheon, and Ulsan, respectively. Sulfate was the largest constituent in both Chuncheon and Ulsan, while nitrate was in Seoul. Potential source contribution function (PSCF) was applied in order to identify both the local and regional sources affecting enhanced PM2.5 concentrations in Korea. The southern industrialized area in Korea, including the cities Pohang and Ulsan, was identified as the local sources, and industrial facilities located in eastern China and southern Japan were determined to be the regional sources. [Copyright &y& Elsevier]

We present a fractal study of the public transportation system of Seoul, composed of subway and railway lines. The fractal dimension of the whole network is determined for several years, indicating an increase of D, which is the actual fractal dimension of the lines, from 1.15–1.35. We also determined the actual dimension of the ensemble of the stations (1.50). We discuss the significance of the fact that the fractal dimension of the stations is larger than that of the lines and conclude that it could be a measure of the quality of the system. Our results are compared with those concerning Paris, for which the two fractal dimensions have also been determined. [Copyright &y& Elsevier]

This study aimed to enhance the accuracy of extreme rainfall forecast, using a machine learning technique for forecasting hydrological impact. In this study, machine learning with XGBoost technique was applied for correcting the quantitative precipitation forecast (QPF) provided by the Korea Meteorological Administration (KMA) to develop a hydrological quantitative precipitation forecast (HQPF) for flood inundation modeling. The performance of machine learning techniques for HQPF production was evaluated with a focus on two cases: one for heavy rainfall events in Seoul and the other for heavy rainfall accompanied by Typhoon Kong-rey (1825). This study calculated the well-known statistical metrics to compare the error derived from QPF-based rainfall and HQPF-based rainfall against the observational data from the four sites. For the heavy rainfall case in Seoul, the mean absolute errors (MAE) of the four sites, i.e., Nowon, Jungnang, Dobong, and Gangnam, were 18.6 mm/3 h, 19.4 mm/3 h, 48.7 mm/3 h, and 19.1 mm/3 h for QPF and 13.6 mm/3 h, 14.2 mm/3 h, 33.3 mm/3 h, and 12.0 mm/3 h for HQPF, respectively. These results clearly indicate that the machine learning technique is able to improve the forecasting performance for localized rainfall. In addition, the HQPF-based rainfall shows better performance in capturing the peak rainfall amount and spatial pattern. Therefore, it is considered that the HQPF can be helpful to improve the accuracy of intense rainfall forecast, which is subsequently beneficial for forecasting floods and their hydrological impacts. [ABSTRACT FROM AUTHOR]

Due to global warming, the reducing air pollution is an important policy issue in the metropolitan area. Since the road mobile pollutant is the probable reason for the air quality pollution, the electric vehicle expansion is one of the main strategies for sustainable transportation systems. The expanded distribution of electric taxis depends on the important task of securing the investment feasibility compared to the currently operating liquefied petroleum gas (LPG) taxis. One thing to note is that a validity analysis is required to secure the sustainability of the switch from LPG to electric taxis and for the effective distribution of investment resources. This study has diagnosed the implementation potential of electric taxis by analyzing the operating and charging behaviors of electric taxis from actual digital tachometer data which is consist of speed, driving distance, power usages of power train and by carrying out the feasibility study and environmental analysis for implementing electric taxis. It was found that the financial feasibility exists in converting private taxis to electric taxis, and the implementation potential is high. Moreover, the environmental analysis showed that socioeconomic benefits would be created with reduced air pollutants and CO 2 from electric taxi operations. As a result of feasibility study, the implementation of electric taxis is feasible from both financial and environmental perspectives under the current subsidy situations. Thus, attempts for sustainable urban transportation structure should be supported by operating behaviors, charging infrastructure, regulations, policies, and battery technology for the promotion of electric taxis. [ABSTRACT FROM AUTHOR]