Search Results (204)

This paper investigates a UAV-assisted wireless communication system that integrates optical wireless communication (LiFi) with conventional RF links to enhance network capacity in crowd-gathering scenarios. While the unmanned aerial vehicle (UAV) serves as a flying base station providing downlink transmission to mobile ground users, the study places particular emphasis on the role of LiFi as a complementary physical layer technology within heterogeneous networks—an aspect closely connected to optical and photonics advancements. The proposed system is designed for environments such as theme parks and public events, where user groups move collectively toward points of interest (PoIs). To maintain quality of service (QoS) under dynamic mobility, we develop a joint optimization framework that simultaneously designs the UAV’s flight path and resource allocation over time. Given the problem’s non-convexity, a block coordinate descent (BCD) based approach is introduced, which decomposes the problem into power allocation and path planning subproblems. The power allocation step is solved using convex optimization techniques, while the path planning subproblem is handled via successive convex approximation (SCA). Simulation results demonstrate that the proposed algorithm achieves rapid convergence within 3–5 iterations while guaranteeing 100% heterogeneous QoS satisfaction, ultimately yielding nearly 15.00 bps/Hz system capacity enhancement over baseline approaches. These findings motivate the integration of coordinated three-dimensional trajectory planning for multi-UAV cooperation as a promising direction for further enhancement. Although LiFi is implemented in free-space optics rather than fiber-based sensing, this work highlights a relevant optical technology that may inspire future cross-domain applications, including those in optical sensing, where UAVs and reconfigurable optical links play a role. Full article

Arbuscular mycorrhizal fungi (AMF) form symbiotic associations with most vascular plants and play an important role in immobilizing heavy metals in soil. Urban green space ecosystems are increasingly affected by heavy metal pollution; however, how different types of green spaces influence AMF diversity, stability, and coexistence mechanisms under heavy metal stress remains unclear. Here, heavy metal-contaminated soil samples were collected from Zhengzhou, China—a large city in the warm temperate monsoon zone of the North China Plain—to conduct high-throughput sequencing and analyze AMF community assembly. (1) AMF community composition varied significantly among green space types, with higher diversity in park green spaces (Shannon = 21.24 ± 2.24) than in street green spaces (Shannon = 11.36 ± 1.17). (2) Heavy metals were the primary factors driving AMF community assembly. Stochastic processes, mainly dispersal limitation, dominated AMF assembly across sites, with a stronger influence in street green spaces. (3) Specialist taxa (mainly Glomus and Claroideoglomus) exhibited higher network connectivity and stability in park green spaces, whereas generalist taxa maintained network resilience in street green spaces. This study elucidates the ecological processes shaping AMF communities in urban ecosystems and provides a scientific basis for AMF-based approaches to heavy metal remediation and sustainable management of urban green spaces. Full article

Urban green spaces, as vital land use components, play a crucial role in promoting public mental health and well-being. This study investigates the differential restorative benefits and stress relief pathways in urban green spaces for populations with varying stress thresholds. This study employed a controlled experiment (pre-test–free activity–post-test) with 120 park users, integrating subjective scales (DASS-21, SRRS, etc.). We innovatively stratified participants by stress threshold to analyze recovery mechanisms. Key findings reveal: (1) Park visits were associated with significant restorative benefits across all stress groups (p < 0.05), yet the recovery patterns and potential pathways appear to be stress-threshold-dependent. (2) Our findings suggest distinct patterns: low-stress individuals benefit via cognitive-behavioral routes (environmental awareness, dynamic activities), while medium-high stress groups rely more on physiological regulation (environmental enclosure, static relaxation). (3) Crucially, these mechanisms suggest stratified landscape design strategies: multi-sensory interactive spaces for low-stress, static rest areas for medium-stress, and low-interference, high-enclosure meditative environments for high-stress individuals. However, given the single-group pre-post design, observed benefits should be interpreted as associations and plausible pathways rather than definitive causal effects. By introducing stress threshold stratification into restorative landscape research, this study provides actionable, evidence-based guidelines for optimizing urban green space planning and design. It offers a crucial scientific foundation for creating healthier, more inclusive, and sustainable urban environments that effectively address diverse mental health needs and contribute to public health promotion through sustainable land use practices. Full article

As urbanization advances toward refined territorial spatial governance, integrating comprehensive transportation and spatial vitality has become essential for sustainable urban development. Transit-oriented development (TOD) plays a key role in linking transportation infrastructure with the coordinated evolution of territorial space. However, the interaction mechanisms between the built environment and metro station area vitality in cold-region cities remain underexplored, particularly in relation to seasonal differentiation. Taking Harbin as a representative cold-region metropolis, this study investigates how built environment factors shape metro station area vitality across seasons and how their spatial mechanisms differ between winter and summer. An indicator system based on the “5D” framework was established, and K-means clustering was applied to classify stations into four coordinated spatial types. A composite vitality index integrating transportation, social, and economic dimensions was constructed to assess seasonal variations. Spearman correlation and XGBoost models identified dominant drivers at the global level, while the MGWR model revealed spatial heterogeneity. The results indicate that POI density exerts the strongest influence on metro station area vitality, contributing 47.95% in winter and 47.27% in summer. Residential density plays a more decisive role during summer, accounting for 18.90%. In contrast, winter vitality depends more on transportation accessibility, with the distance to parking facilities contributing 11.59%. Core urban stations consistently maintain high vitality, while peripheral areas have weaker performances, especially during winter. These findings clarify seasonally adaptive mechanisms linking the built environment and spatial vitality, providing evidence for coordinated optimization of metro systems and land-use planning in cold-region cities. Full article

The 15-minute city (15MC) model has gained increasing attention as a framework for promoting sustainable urban living by ensuring that essential services, including urban green spaces (UGSs), are accessible within short walking or cycling distances. UGSs play a vital role in public health, social interaction, and environmental resilience, yet questions remain about how equitably they are distributed and accessed in cities. This study assesses proximity and accessibility to UGSs in Porto, Portugal, through the lens of the 15MC. The methodology combined a GIS-based spatial analysis of walking and cycling catchments with a complementary questionnaire to capture user perceptions and travel behaviors. Results show that, while 84% and 100% of residents live within a 15-minute walking and cycling distance of a UGS, respectively, accessibility remains uneven, particularly for walking. Large peripheral parks contribute significantly to provision but remain less accessible to central neighborhoods, and cycling to UGSs is marginal due to fragmented and insufficient infrastructure, and residual cycling use. Subjective findings mirrored the spatial analysis, highlighting dissatisfaction with cycling conditions and only moderate satisfaction with pedestrian environments. The study emphasizes the need for integrated planning that improves local connectivity, infrastructure quality, and spatial equity to fully realize the 15MC vision. Full article

At present, the research on the microclimate of urban parks mainly focuses on the univariate or multivariate research contents of park design elements, and there are few analyses that can combine the park with the surrounding regional environment to jointly explore the cooling mechanism of park design elements. This study takes the People’s Park in Urumqi, a typical oasis city in an arid area, as the research object. Combined with different land use natures (park area/residential area), it analyzes the spatiotemporal variation law of temperature through mobile meteorological monitoring in different periods of summer and autumn and optimizes the buffer zone to further compare the performance of the multiple linear regression model and three machine learning models. The selection of the optimal model for collaborative analysis and comparison revealed the dominant variables and their threshold effects affecting the temperature of the park area and the residential area. The results show that: (1) In multi-scenario comparisons, a larger buffer has a better fitting effect. (2) The random forest model is the best model for temperature prediction in the study area. (3) The dominant factors of temperature in different seasons show significant differences, and only a few periods have cross-seasonal persistence. In the park area, the green coverage rate and road network density play a leading and influential role, while in the residential area, the influence of water cover ratio is more obvious. Furthermore, the influence direction of residential area indicators on temperature shows opposite trends in the morning and afternoon periods. (4) There are obvious limited-threshold effects on the influence of dominant factors on temperature in different regions. It is suggested that in the urban spatial layout, while considering the differences for different utilization Spaces, collaborative planning should be carried out. These findings offer new insights into temperature drivers and provide practical references for urban planners. Full article

Urban park green spaces (UPGSs) play a critical role in enhancing residents’ quality of life, particularly for older adults. However, inequities in accessibility and resource distribution remain persistent challenges in aging urban areas. To address this issue, this study takes Gulou District, Nanjing City, as an example and proposes a comprehensive framework to evaluate the overall quality of UPGSs. Furthermore, an enhanced Gaussian two-step floating catchment area (2SFCA) method is introduced that incorporates (1) a multidimensional park quality score derived from an objective evaluation system encompassing ecological conditions, service quality, age-friendly facilities, and basic infrastructure; and (2) a Gaussian distance decay function calibrated to reflect the walking and public transit mobility patterns of the older adults in the study area. The improved method calculates the accessibility values of UPGSs for older adults living in residential communities under the walking and public transportation scenarios. Finally, factors influencing the social equity of UPGSs are analyzed using Pearson correlation coefficients. The experimental results demonstrate that (1) high-accessibility service areas exhibit clustered distributions, with significant differences in accessibility levels across the transportation modes and clear spatial gradient disparities. Specifically, traditional residential neighborhoods often present accessibility blind spots under the walking scenario, accounting for 50.8%, which leads to insufficient accessibility to public green spaces. (2) Structural imbalance and inequities in public service provision have resulted in barriers to UPGS utilization for older adults in certain communities. On this basis, targeted improvement strategies based on accessibility characteristics under different transportation modes are proposed, including the establishment of multi-tiered networked UPGSs and the upgrading of slow-moving transportation infrastructure. The research findings can enhance service efficiency through evidence-based spatial resource reallocation, offering actionable insights for optimizing the spatial layout of UPGSs and advancing the equitable distribution of public services in urban core areas. Full article

Minor Southern Italian population centers present a fragmented and uneven urban landscape, resulting from abandonment and depopulation phenomena that have led, especially in historic city centers, to urban voids scattered with rubble, buildings in a state of ruin, and others with evident structural collapses. Within a broader urban regeneration strategy for these centers, aligned with current national and European policies, the recovery of these vacant spaces can play a decisive role in enhancing urban quality and the desired touristic appeal, with social, economic, and environmental implications. These areas may also become valuable resources for innovating the urban core in a green transition process, contributing to carbon neutrality goals while improving residents’ quality of life. This paper addresses the importance of pocket parks as systems of resilience against climate change and hydrogeological risks, as well as rainwater drainage systems in densely built urban areas with strong historical character. The study includes a case study application focusing on a location in the Sicilian hinterland, notable for its historical and architectural value. The urban center under examination, Naro in the province of Agrigento, has experienced significant depopulation over the past fifty years, and the designation of its provincial capital as the Italian Capital of Culture 2025 could provide the opportunity for revival through small-scale, low-cost, and sustainable actions. Full article

Urban parks play a crucial role in mitigating urban heat stress and maintaining ecological stability through their cold island effect (PCIE). However, studies examining how multidimensional urban morphology influences these effects, particularly from a diurnal perspective in island cities, remain limited. This study investigates 30 representative urban parks within a typical island city, exploring how two-dimensional and three-dimensional spatial morphological factors affect four key PCIE indicators: park cooling intensity (PCI), park cooling gradient (PCG), park cooling area (PCA) and park cooling efficiency (PCE) across different times of day and night. The results reveal that: (1) coastal zones exhibit significantly lower land surface temperature (LST) than inland zones, with peak LST occurring at 5:00 p.m.; (2) the four cold island indicators follow a diurnal pattern of 5:00 p.m. > 1:00 a.m. > 7:00 a.m.; (3) morphological construction factors—such as building density (BD) and built-up proportion (BP)—positively contribute to cooling effects at 7:00 a.m., while park perimeter (PP) enhances cooling performance at both 5:00 p.m. and 1:00 a.m. Additionally, vegetation characteristics surrounding parks, including the normalized difference vegetation index (NDVI) and green space proportion (GP), influence daytime cooling in directions opposite to those of the aforementioned construction-related factors. These findings offer valuable insights into the temporal dynamics and spatial determinants of urban park cooling in island cities, providing a scientific basis for scientifically informed park planning and contributing to healthier and more sustainable urban development. Full article

The building sector plays a key role in the transition toward climate neutrality, with national regulations across the EU requiring the construction of nearly zero-energy buildings (nZEBs). However, while energy performance has been extensively studied, less attention has been given to the problem of ensuring user comfort—both indoors and in the surrounding outdoor areas—under nZEB design constraints. This gap raises two key research objectives: (1) to evaluate whether a well-designed nZEB with extensive glazing maintains acceptable indoor thermal comfort and (2) to assess whether residents experience greater outdoor thermal comfort and satisfaction in small, sun-exposed private gardens or in larger, shaded communal green spaces. To address these objectives, a newly built residential estate near Kraków (Poland) was analyzed. The investigation included simulation-based assessments during the design phase and in situ measurements during building operation, complemented by a user survey on spatial preferences. Indoor comfort was evaluated for rooms with large glazed façades, as well as rooms with standard-sized windows, while outdoor comfort was assessed in both private gardens and a shared green courtyard. Results show that shading the southwest-oriented glazed façade with an overhanging terrace provided slightly lower temperatures in ground-floor rooms compared to rooms with standard unshaded windows. Outdoors, users experienced lower thermal comfort in small, unshaded gardens than in the larger, vegetated communal area (pocket park), which demonstrated greater capacity for temperature moderation and thermal stress reduction. Survey responses further indicate that potential future residents prefer the inclusion of a shared green–blue infrastructure area, even at the expense of building some housing units in semi-detached form, instead of maximizing the number of detached units with unshaded individual gardens. These findings emphasize the importance of addressing both indoor and outdoor comfort in residential nZEB design, showing that technological efficiency must be complemented by user-centered design strategies. This integrated approach can improve the well-being of residents while supporting climate change adaptation in the built environment. Full article

The Surface Cool Island (SCI) refers to localized reductions in land surface temperature (LST) produced by features that enhance evapotranspiration, shading, and energy flux regulation. In arid urban areas, vegetated parks play a key role in mitigating heat through these mechanisms. This study evaluates how park vegetation structure and spatial configuration influence SCI intensity (ΔTmax) and extent (Lmax) using multi-seasonal, day–night satellite observations in Mexicali, Mexico. A total of 435 parks were analyzed using Landsat 8/9 TIRS (30 m) for LST and Sentinel-2 MSI (10 m) for vegetation mapping via NDVI thresholding and supervised random forest (RF) classification. On average, parks lowered daytime LST by 0.81 °C (max: 6.41 °C), with a mean Lmax of 120 m; nighttime cooling was weaker (avg. ΔTmax: 0.37 °C; Lmax: 48 m). RF-derived metrics explained SCI variability more effectively (R² up to 0.64 for ΔTmax; 0.48 for Lmax) than NDVI-based metrics (R² < 0.35), highlighting the value of object-based land cover classification in capturing vegetation structure. This remote sensing framework offers a scalable method for assessing urban cooling performance and supports climate-adaptive green space design in hot-arid cities. Full article

With the increasing importance of urban green spaces in leisure, ecology, emergency management, and other functions, urban forest parks play a key role in enhancing urban tourism resilience. Tourists are closely related to this, but current research lacks discussion on the sustainable development of urban forests and tourism resilience from the perspective of tourist demand. Therefore, this study took Kunming Xishan Forest Park as an example, conducted a questionnaire survey of 385 tourists, and identified tourist demands and weights through in-depth analysis using the KANO model and AHP. The results data show that among the 23 demand indicators across five dimensions, six are must-be qualities, eight are one-dimensional qualities, six are attractive qualities, and three are indifferent qualities. Based on the AHP analysis, we further investigated the weight of each demand indicator. The results of this study not only provide practical support and strategic guidance for the spatial planning and design of urban forests, thereby enhancing the sustainable development of urban tourism resilience, but also contribute to theories of urban tourism resilience and offer a reference source for other cities with similar aspirations. Full article

Parks, as essential elements of urban green public spaces, play a crucial role in sustainable urban development. Their features have features confirmed to significantly affect park vitality. Prior research has indirectly indicated that park features might impact park vitality via interaction and synergy; however, such effects have been neglected in park vitality studies. The study area is South China, with data collected from 20 urban comprehensive parks in 8 representative cities. This study constructs linear mixed models of principal component main effects, interaction effects, and synergy effects to empirically examine the interaction of internal element features and the synergy of external environmental features affecting park vitality. The findings indicate: (1) Structural interaction effects exist among internal element features that impact park vitality. The structures of “medium plaza + small plaza” and “primary park road + open grassland” significantly enhance vitality. Conversely, the structure of “aquatic plant coverage area + lake + dense woodland” has a negative influence. Single structure features are ineffective in significantly influencing park vitality. (2) The inclusion of interaction terms between internal feature structures enhances the significance of their effects on vitality. The interaction of “medium plaza + small plaza” × “primary park road + open grassland” shows the strongest effect. (3) There is a synergy between internal and external features: with external features like accessibility and disposable income, certain internal interaction structures positively contribute to vitality. Additionally, the “service capacity” external environmental feature exhibits a negative synergy with internal element features. These findings provide theoretical and practical insights for sustainable urban park design, planning, and refined management in cities with similar socioeconomic and spatial contexts. Full article

The rapid industrialization and urbanization of the modern era caused widespread deforestation and ecological degradation, raising global concerns about sustainable planning, urban green space, and environmental governance. Around the turn of the 20th century, Guangdong Province in China suffered severe environmental decline due to extensive deforestation, threatening public health, ecological resilience, and urban livability. In response, returning Chinese intellectuals and foreign forestry experts introduced advanced Western forestry theories and practices to address these crises and promote green urban development. This study examines how these transnational forestry ideas were ideologically embraced, locally adapted, and institutionally embedded in modern Guangdong’s afforestation and urban greening efforts. Drawing on a systematic review of historical literature, forestry journals, and government archives, it identifies three key developments. (1) In ideology, figures such as Yat-sen Sun and German forester Fenzel played vital roles in raising public awareness of afforestation. (2) In practice, Guangdong developed a diversified greening model integrating commemorative, ecological, and aesthetic functions. This included transforming Arbor Day into a civic ritual honoring Yat-sen Sun, establishing nurseries and forest farms for large-scale afforestation, systematically planting street trees in urban centers, and creating forest parks that combined conservation, recreation, and historical commemoration. (3) In regulation, Guangdong formulated forestry laws inspired by Western models. By this way, Guangdong effectively addressed the management challenges in urban greening practices. It should also be emphasized that these modern-era practices have persisted in Guangdong, and their historical experience provides a valuable reference for present-day urban greening. Additionally, Fenzel’s methods for planning nurseries and forest farms can be seen as early prototypes of “evidence-based planning”. By highlighting a historically grounded yet under-explored case, this research offers new insights into the long-term evolution of urban greening strategies and provides lessons for current global efforts in sustainable land use and resilient urban design. Full article

Natural playgrounds have garnered growing attention as supportive environments for children’s mental health. This study develops an analytical framework grounded in affordance theory and incorporates the Pleasure–Arousal–Dominance (PAD) model to examine the relationships between physical environmental features—and their combinations—in natural playgrounds and children’s emotional perceptions. Using the Yunhu Natural Playground in Fuzhou, China, as a case study, we selected seven typical behavior setting units. Environmental features were assessed through UAV imagery and on-site observations, while PAD-based visual questionnaires were employed to collect emotional responses from 159 children. By applying correlation analysis, random forest, and regression tree models, this study identified key environmental predictors of children’s emotional responses and revealed heterogeneous mechanisms across the three emotional dimensions. The results indicated that seasonal flowering/fruiting plants, accessible lawns, and structured play facilities were critical in supporting children’s pleasure, arousal, and dominance. Specifically, pleasure was primarily associated with sensory enjoyment and contextual aesthetics, arousal favored open grassy areas, and dominance was linked to environments with clear structure and manipulability. Based on these findings, this study proposes a spatial configuration strategy characterized by “nature as foundation, play encouraged, and structure clarified” to promote the positive development of children’s multidimensional emotional experiences. This research contributes empirical evidence on the role of physical environmental features in supporting children’s play behaviors and expands the theoretical understanding of the “emotional effects” of green spaces. While the findings are exploratory and context-specific, they emphasize the critical role of the sensory–behavioral–emotional chain in shaping children’s well-being and provide theoretical and practical guidance for the design of emotionally supportive, child-friendly, natural play environments in schools, parks, and residential areas. Full article