Earticle

This study notes that energy consumption in the domestic building sector recently accounts for more than 20% of the total final energy use, with residential buildings representing the highest share—approximately 54.9% as of 2024. This outcome results from multiple factors, including an increase in the number of households, diversification of housing types, and improvement in living standards, indicating that the residential sector has emerged as a key area in national energy policy and carbon-neutral strategies. Therefore, this study aims to analyze temporal changes in energy consumption and energy use intensity (EUI, kgoe/㎡) for detailed residential building types——single-family house, lodging house, multi-family house, low-rise house, medium-rise house, and apartment house—using multi-year integrated data from 2018 to 2024. Through this analysis, the study seeks to identify the effects of housing-type transitions on energy consumption structures and to provide foundational data for developing housing-type-specific reduction strategies and low-carbon residential policies.

In Japan's suburban residential areas, while traditional community events are declining as the population ages, it has been noted that small-scale, low-impact events run spontaneously by residents may be sustainable. This study focuses on the "Burabura Festival" in Oshizawadai Kita, Kozoji New Town, as well as its development in adjacent and neighboring districts, to clarify (I) organizational structure and management methods, (2) relationship with government and neighborhood association support, (3) factors for continuation, and (4) diffusion routes to other areas. The methods employed were semi-structured interviews with the initiators and organizers of the diffusion areas, analysis of materials from booklets and handouts, and on-site observation at the initiative's site. As a result, the low burden design of minimal integration by the secretariat (initiator) and executive committee, distribution to all households and word-of-mouth-centered publicity, free participation and no selection of stalls, and common tool-centered costs supported sustainability. In addition, "loose knowledge transmission" through inspection tours, word of mouth, booklets, and other means led to the establishment of indigenous management styles in other regions, such as those without a secretariat and those led by welfare organizations. These results suggest that resident-led events with low institutional dependence can be an effective model for revitalizing community activities in suburban residential areas.

In modern Korean society, housing is recognized as an important investment asset beyond a simple living space, and residential consumption culture varies according to individual tendencies and values. This study aims to cluster apartment residents by housing selection determinants and analyze differences in residential environment priorities between groups, thereby providing insights for housing suppliers to respond to diverse consumer needs. A survey was conducted on 96 apartment residents in Gwangju Metropolitan City. The data were analyzed using cluster analysis and IPA (Importance-Performance Analysis). Reliability and validity of the measurement instruments were confirmed through statistical verification. Two distinct resident types were identified: the 'Future Value Leading' group (58 residents, 60.4%) and the 'Conservative Reality-Considering' group (38 residents, 39.6%). The 'Future Value Leading' group showed investment-oriented tendencies, emphasizing asset value, complex reputation, and premium finishes. Their IPA results showed importance and satisfaction scores of 3.96 and 3.53 respectively, with priority improvements needed in structural safety, brand value, and parking facilities. The 'Conservative Reality-Considering' group demonstrated pragmatic tendencies, emphasizing energy efficiency, environmental friendliness, and social consideration. Their scores were 3.79 and 3.25 respectively, with priorities in energy performance, recycling facilities, and barrier-free design.The findings suggest that differentiated approaches are necessary in apartment housing planning and remodeling. For remodeling projects, resident type diagnosis should precede planning to align improvement priorities with dominant resident characteristics. Housing suppliers should develop customized strategies reflecting each group's values, and policymakers should promote inclusive housing policies accommodating diverse residential preferences.

This study experimentally investigated the effects of fire door thickness on airtightness and thermal insulation performance for apartment unit entrance doors. Fire door specimens with thicknesses of 45, 55, 65, and 75 mm were tested for airtightness in accordance with KS F 2292 and for thermal transmittance in accordance with KS F 2278. The airtightness test results showed that all specimens satisfied the Grade 1 requirement. However, no consistent reduction in infiltration rate was observed with increasing door thickness. In contrast, thermal insulation performance exhibited a clear dependence on thickness. The thermal transmittance (U-value) decreased from 1.58 [W/(m²·K)] at 45 mm to 1.23 [W/(m²·K)] at 75 mm. Regression analysis revealed a strong negative correlation between door thickness and thermal transmittance (r = −0.958, p < 0.05). These results indicate that airtightness and thermal insulation performance respond differently to changes in fire door thickness.

This study analyzes aging degradation in apartment fire doors and proposes maintenance improvements. 146 fire resistance test cases from defect lawsuits (2022–2024) were quantitatively analyzed. Although the data involves selection bias from high-risk samples, it offers empirical insights into fire door performance. The results showed a 54.1% overall failure rate, soaring to 94.1% in apartments over 10 years old, indicating a severe loss of safety functionality. This degradation stems from physical aging and historical practices, particularly the use of honeycomb cores (80.6% failure) and pivot hinges (37.8% failure). Since 2013, a shift toward mineral wool cores and butt hinges has significantly improved stability. Simulations proved that timely replacement of gaskets and hardware could reduce failure rates to the 40% range. The study suggests a differential management strategy: prioritizing the replacement of older doors with honeycomb cores and pivot hinges while strengthening preventive maintenance for modern systems.

To expand aviation infrastructure in the Jeju region, distribute air travel demand, and ensure a smooth flow of air transport, a multi-airport system-operating two airports within the Jeju region-has been adopted. In such systems, where two or more airports coexist in one region, airport operations are inevitably influenced by inter-airport competition for operating revenue, legal and regulatory constraints, and political decision-making processes. Accordingly, this study analyzes the architectural planning characteristics of role sharing at the Jeju Second Airport based on air travel demand at the existing Jeju Airport by airline route category (international/domestic) and by airline business model (FSC, Full-Service Carrier/LCC, Low-Cost Carrier), and multi-airport role-sharing scenarios presented in the “Research Service for Establishing the Basic Plan for Jeju Second Airport”. Demand is examined with particular attention to FSC and LCC segments. By doing so, the study seeks to assess the adequacy of the passenger terminal scale proposed in the “Basic Plan for the Jeju Second Airport Construction Project” and to identify areas for improvement, ultimately proposing directions for a more efficient operational strategy for the Jeju multi-airport system.

In this study, the electrical and mechanical properties of compression members strengthened with self-sensing cement grout for section enlargement were investigated. When section enlargement was performed using self-sensing cement grout, the compressive strength increased, and the fractional change in resistance (FCR) tended to decrease as load and strain increased. WWhen a stress level corresponding to 25% of the compressive strength was applied and subsequently removed, the FCR returned to a value similar to that before loading due to elastic recovery. In contrast, when a stress level of 50% was applied, the strain progressed into the plastic region, leading to permanent strain. Consequently, the FCR decreased further. Additionally, the FCR-Stress and FCR-Strain relationships obtained through the estimation equations exhibited a strong correlation.

The decline in the school-age population has led to a serious issue of underutilized school facilities, making it necessary to explore strategies for repurposing school sites. In this context, understanding utilization approaches according to the characteristics of closed school sites has become crucial. This study focuses on closed school sites in small- and medium-sized cities outside the Seoul metropolitan area, where school closures are more prevalent, and classifies their use into three categories: sold, reuse, and non-use. Using the Ministry of Education’s data on the utilization status of closed school properties, the study analyzes differences in locational and site characteristics across these groups. For quantitative variables, ANOVA was employed to compare means, while for categorical variables, chi-square tests were conducted to examine proportional differences. The results reveal that closed school sites with good accessibility, abundant population and demand, and urbanized surroundings are more likely to be reused. In addition, sites that are larger in size, rectangular in shape, and have higher official land values were found to be primarily reused.