Since the advent of reforms and opening-up of China, the focus has been on urban development. However, rural development has garnered attention in recent years. This research explores energy performance improvement methods for rural houses in Xi’an, China. It aims to discuss the feasibility of designing a nearly zero-energy building (nZEB), based on typical residential rural housing in Xi’an, through proposing new construction methods and examining the strategies for the refurbishment of an existing house. Initially, a typical rural house was modelled based on data collected from a field survey and historical documents. Subsequently, suitable passive design strategies were explored in the rural house design both in terms of proposing new construction methods and examining the refurbishment strategies of an existing house. After implementation of the passive design, the annual energy demand was reduced from 112 kWh/m² to 68 kWh/m² (new construction) and from 112 kWh/m² to 85 kWh/m² (refurbished). Even though the passive design significantly reduced the energy demand of the house, it could not achieve the Chinese nZEB standard. Therefore, a photovoltaic (PV) system and a storage battery were incorporated to meet the standard. Eighty per cent of the south roof area of the newly constructed and refurbished house was installed with a PV system and a storage battery with a capacity of 50 kWh and 52 kWh, respectively. After installation of the proposed renewable energy, the annual energy demand from the house was decreased to 35 kWh/m² (new construction) and 51 kWh/m² (refurbished), which both achieved the Chinese nZEB standard (equal to or below 55 kWh/m²). The study shows the effectiveness of the methods used to design the nZEB and can be used to instruct the residents to build the nZEB in rural villages like Xi’an in China.

Globally speaking, Asian countries, especially East Asian countries, are facing acute national depopulation situation and severe rural shrinkage development. Based on the continuous surveys of town and village development in Japan, South Korea, and China, this study aims to provide an overview of social policies that have been implemented in the past or more recently in these three countries in response to rural shrinkage, and to outline the core philosophy of these practices to cope with the repercussions. In this paper, we analyze the overall process of rural depopulation and the present features of town and village development in three countries. We subsequently present the social policies over the last few decades and summarize them into four major groups. Furthermore, we highlight that the focus of social policies is not to seek possible ways to reestablish growth but to provide positive support and effective reform to adjust and satisfy the changing needs of towns and villages under the circumstances of shrinking development, including the optimization of public resource allocation, exploring institutional innovation to valorize abandoned assets, and developing endogenous potentials for future sustainable development. Qualitative methods from a combination of literature review, policy review, and field surveys have mainly been adopted in this research. The study of East Asian practices may be instructive for other Asia-Pacific countries, as well as European countries that have been experiencing or will eventually face the challenges of rural shrinkage.

With the rapid advancement of computer graphics and three-dimensional modeling technology, the processing and optimization of three-dimensional (3D) models have become contentious research topics. In the context of mobile devices or web applications, situations may arise where it becomes necessary to load a 3D model with a substantial memory footprint in real-time or dynamically adjust the level of detail of a model based on the scene’s proximity. In such cases, it is imperative to optimize the original model to ensure smoothness and responsiveness. Due to the simplicity of their algorithm, quadric error metrics (QEMs) can deliver excellent results in simplifying 3D models while maintaining high efficiency. Therefore, QEM is widely employed in engineering applications within the realm of computer graphics development. Moreover, in the pursuit of enhanced quality and efficiency, numerous scholars have improved it based on QEM algorithms. This study aims to provide a systematic review and summary of the principles and applications of current research on QEM algorithms. First, we conducted a bibliometric analysis of 128 studies in related fields spanning from 1998 to 2022 using CiteSpace. This allowed us to sort QEM algorithms and gain insights into their development status and emerging trends. Second, we delve into the fundamental principles and optimizations of the QEM algorithms to provide a deeper understanding of their implementation process. Following that, we explore the advantages and limitations of the QEM algorithms in practical applications and analyze their potential in various domains, including virtual reality and game development. Finally, this study outlines future research directions, which encompass the development of more efficient error metric calculation methods, the exploration of adaptive simplification strategies, and the investigation of potential synergies with deep learning technologies. Current research primarily centers on enhancing QEM algorithms by incorporating additional geometric constraints to better differentiate between flat and irregular areas. This enables a more accurate determination of the areas that should be prioritized for folding. Nevertheless, it is important to note that these improvements may come at the cost of reduced computational efficiency. Therefore, future research directions could involve exploring parallel computing techniques and utilizing GPUs to enhance computational efficiency.

In recent years, urban regeneration strategic plans have been implemented across South Korea to curb the negative impacts of depopulation, physical deterioration and economic decline. By adopting a people-centered regeneration process, context-sensitive plans are formulated by integrating local people’s perceptions and expectations. This paper examines urban regeneration plans implemented in Ami-dong Tombstone Cultural Village, a declining hillside village in Busan, using “people–place–process framework of place attachment” to analyze the process of articulating “sense of place” through community-driven approaches. Based on archival research, site investigations, secondary data and semi-structured interviews, the paper explores the revival of social capital, integration of place-sensitivity and improvement of everyday landscapes through affective, behavioral and cognitive responses of urban professionals and community members involved in the project. Findings of the study show that place attachment, sense of community and community participation in regeneration can help in re-creating meaningful places. Lessons from Ami-dong offer insights on ways to strengthen people–people and people–place relationships through design and planning processes in a declining context with an aging population.

With increasing consumption of primary energy and deterioration of the global environment, clean energy sources with large reserves, such as natural gas, have gradually gained a higher proportion of the global energy consumption structure. Monitoring and predicting consumption data play a crucial role in reducing energy waste and improving energy supply efficiency. However, owing to factors such as high monitoring device costs, safety risks associated with device installation, and low efficiency of manual meter reading, monitoring natural gas consumption data at the household level is challenging. Moreover, there is a lack of methods for predicting natural gas consumption at the household level in residential areas, which hinders the provision of accurate services to households and gas companies. Therefore, this study proposes a gas consumption monitoring method based on the K-nearest neighbours (KNN) algorithm. Using households in a residential area in Xi’an as research subjects, the feasibility of this monitoring method was validated, achieving a model recognition accuracy of 100%, indicating the applicability of the KNN algorithm for monitoring natural gas consumption data. In addition, this study proposes a framework for a natural gas consumption prediction system based on a backpropagation (BP) neural network.

The traditional clan-based structure of village society is gradually disintegrating due to rural population outflow and excessive tourism development. The construction of a diversified development model oriented toward the needs of local villagers is key to sustainable development and the preservation of cultural heritage. In this study, a case analysis of the Ding, Shijiagou, and Yanjing Villages in Shanxi Province was conducted. The research approach of “cognitive recognition–spatial structure–social connections” was used to integrate cognitive maps and space syntax with social network analysis to quantitatively analyze the cognitive elements in these villages, with the establishment of a collective cognitive map, global integration value maps, and villagers’ intention element cognitive networks based on functional types. The spatial cognition patterns and social network structures of these villages were explored and analyzed in relation to the complex interactions between villages from the perspectives of spatial cognitive preference, spatial accessibility, and social interaction to compensate for the limitations of using a single analytical approach. Differences in village cognition patterns were found—the efficient use of different types of space is influenced by spatial cognitive preferences; the degree of spatial integration affects the distribution of functional spaces, with high-integration areas tending to overlap with high-cognition spaces and featuring strong accessibility and connectivity; the density and stability of social networks significantly influence spatial cognition and the interaction patterns in villages; high-density networks enhance the frequency of interactions between villagers and the effectiveness of space utilization; and differentiation in spatial cognition among different groups may reduce village space integration, thereby influencing the overall social functions and cultural heritage of the village. Therefore, it is crucial to enhance the connectivity and influence of key nodes, optimize spatial layouts and social network structures, and introduce modern elements while preserving traditional culture, an approach that can promote social interaction and spatial vitality in the villages. This study provides a scientific basis and serves as a reference for the construction of sustainable development models for villages.