This study explored questions of (1) whether certain areas of South Korea experienced inequal accessibility to public health centers, private hospitals/clinics, and general hospitals by car and public transportation using gaussian mixture models (GMM) and (2) whether socially disadvantaged socioeconomic groups faced disproportionate burdens on accessibility to the multi-tier healthcare services employing ordinary least square regression models (OLS). This study used nationwide accessibility indicators in South Korea measured by Korea Transport Institute in 2019. The main findings were as follows: First, the results of the GMM indicate that the degree of accessibility to healthcare services was significantly lower in rural, mountainous, and seaside locations compared to metropolitan areas. Second, there was more considerable inequality in public transportation accessibility than car accessibility. Third, the findings of the OLS reveal a significant relationship between accessibility indicators and socioeconomic variables, such as age, gender, disability, and residential location, which indicates socioeconomic inequality in accessibility in South Korea. This study contributes to shedding light on understanding the spatial and socioeconomic inequality in accessibility across the nation and offering policy implications.

This research investigated spatial inequalities in transportation accessibility to social infrastructures (SIs) in South Korea, using a multi-dimensional methodological approach, including descriptive/bivariate analysis, explanatory factor analysis (EFA), K-Mean cluster analysis, and multinomial logit model (MNL). Our study confirmed pronounced spatial disparities in transportation accessibility to SIs, highlighting significantly lower access in rural and remote regions compared to urban centers and densely populated areas, consistent with existing literature. Building on prior findings, several additional findings were identified. First, we uncovered significant positive correlations among accessibility to different types of SIs in four critical categories: green and recreation spaces, health and aged care facilities, educational institutions, and justice and emergency services, revealing prevalent spatial inequality patterns. Second, we identified three distinct accessibility clusters (High, Middle, and Low) across the critical SI categories. Specifically, residents within the High cluster benefited from the closest average network distances to all SIs, while those in the Low cluster faced significant accessibility burdens (e.g., 22.9 km for welfare facilities, 20.1 km for hospitals, and 19.2 km for elderly care facilities). Third, MNL identified factors such as population density and housing prices as pivotal in spatial stratification of accessibility. Specifically, areas with lower SI accessibility tended to have a higher proportion of elderly residents. Also, decreased accessibility correlated with diminished traffic volumes across all transportation modes, particularly public transportation. This research contributes to enhancing our understanding of spatial inequalities in transportation accessibility to SIs and offers insights crucial for transportation and urban planning.

Three novel classes of porphyrazine‐like structures were synthesized to form modular structures in which lipophilicity and water solubility can be tuned. Subtle modification of solubility is an important criterion in selecting a compound for biological photosensitization. The general structure takes the form H₂[pz(A_nB_4−n)], where the core is a porphyrazine (pz) group, A is a pyrrole ring with two sulfide linkages (SR moieties) and B is a pyrrole fused with a 4,7‐bis(isopropyloxy)benzo group, with n = 4, 3 and 2. These molecules possess their longest wavelength absorption band between 700 and 810 nm, hence laser beams of higher tissue penetration depth could be used to illuminate them in photodynamic therapy (PDT). Armed with absorption bands in the far‐red and near‐infrared (near‐IR), and a capability to tune the solubility, these molecules could make for better sensitizers because of optimized uptake by lipidic membranes and better optical properties. We tested several derivatives of the A₄, A₃B and A₂B₂ structures for their singlet oxygen quantum yields in methanol and in liposomes, using 9,10‐dimethyl anthracene (DMA) as a singlet oxygen target. Singlet oxygen quantum yields in liposomes ranged from 0.01 to 0.44, with the A₂B₂ group showing the most promise. In the binding assay to find the equilibrium binding constant, K_b, we detected fluorescence changes due to a change in environment. Peripheral long‐chain moieties (the R group in the SR moieties) dominate lipid binding. These moieties range in the hydrophobicity that they induce from C₈H₁₇ and benzene, which rendered the molecule totally insoluble in water, to polyethylene glycol (PEG) and carboxylate groups, which imparted water solubility. Each molecule had between 4 and 8 such identical chains. Chains bearing an ether or ester link resulted in measurable equilibrium constants, with a higher K_b for ether substituents. Results for K_b ranged from 0.23 to 26.52 (mg mL⁻¹)⁻¹. A delicate balance exists between water solubility and good partitioning to membranes. In general, a higher oxygen‐to‐carbon ratio in the chains improves binding. Fewer chains and a centrally coordinated zinc ion further improve binding and singlet oxygen production.

Many transit agencies in the United States plan to automate their fare collection and limit–or even eliminate–the use of cash fares, with the goals of expediting boarding, collecting data, and lowering costs. Yet about 10% of US adults lack a bank account or credit card, and many rely on restrictive cellphone data plans or do not have access to the internet or a smartphone. These riders will find it difficult to access transit in the future. This paper examines transit users’ experiences with fare technologies using a survey of riders in three cities. Our analysis reveals which riders are most at risk of being excluded, and how mitigation strategies could work to overcome barriers to cash-less transit. We find that a significant number of riders (∼30%) currently use cash on-board buses. If on-board cash fares were to be removed, a significant share of these riders appear able to switch to other options, though many imagine they will continue to use cash in some way (e.g. at retail or ticket vending machines); a small number claim they would no longer be able to ride transit if on-board cash fares were removed. Older and lower-income riders are more at risk of exclusion as they often lack access to smartphones or the internet. A significant number rely on less dependable internet sources, such as public Wi-Fi, potentially inhibiting some from using smartphone and internet-based payment systems. Findings suggest approaches to reduce the number of riders excluded from transit during fare technology adoption.

This study explored the economic influence of introducing fully autonomous trucks (ATs) on the total cost of operation (TCO) from the viewpoint of freight transport operators. We utilized the cost–benefit analysis and scenario planning frameworks using a case study of a middle-mile route between a port and a large logistics distribution center in South Korea, where an autonomous truck pilot project has been running for several years. We employed a data source obtained from Hanjin Transportation Co., LTD., which enables us to reflect the actual expenses of operating freight transportation in the context of the study route. The findings of this study indicate that ATs would attain substantial operation cost savings for freight transport operators across all five scenarios, ranging from the most pessimistic to the most optimistic. Specifically, results of the base scenario reveal that monthly TCO decreases by 56.25, 47.04, 42.97, and 41.73 percent for 1-, 5-, 12-, and 25-ton trucks, respectively. The cost reduction per month was USD 2399 for a 1-ton truck, USD 2891 for a 5-ton truck, and USD 3438 for a 12-ton truck. Even in the most pessimistic scenario, the operation cost savings for operating with ATs in the route are USD 1415, USD 1642, USD 1985, and USD 2222 per month for 1-, 5-, 12-, and 25-ton trucks, respectively. When factoring in changes in cost, the wage reduction for vehicle drivers was substantial (USD 2430, USD 2835, USD 3240, and USD 3645 for 1-, 5-, 12-, and 25-ton trucks, respectively). However, remote operation was a new cost factor that increased TCO, which increased by USD 243,384,357 in the base case. This study’s findings have multiple implications, including (1) informing economic efficiency and productivity of operating autonomous vehicles (AVs), (2) providing insights on indicative cost estimates for AV operations, (3) providing valuable information for making informed investment decisions, and (4) supporting the notion that freight transport is an especially attractive market for AVs.