Search Results (1,625)

Global Navigation Satellite System (GNSS)/leveling-derived observed geoid heights are widely used to validate gravimetric geoid models and to construct hybrid geoid models for practical height transformation. However, in tectonically active and subsidence-prone regions, these observations may contain errors caused by vertical deformation, benchmark instability, reference-frame differences, and temporal mismatch between GNSS and leveling measurements. This study evaluates the quality of recent GNSS/leveling-derived observed geoid heights in Taiwan and investigates the effects of these inconsistencies on hybrid geoid construction and Light Detection and Ranging (LiDAR)-based coastal low-elevation classification. A vertical velocity field was first used to correct the height changes occurring between the observation epochs of the GNSS-derived ellipsoidal heights and the leveling-derived orthometric heights. The resulting observed geoid heights were then assessed using Leave-One-Out Cross Validation (LOOCV) and an iterative 3σ outlier screening procedure to identify spatially inconsistent observations. The refined dataset was used to construct a hybrid geoid by modeling a correction surface between the gravimetric geoid and the corrected observed geoid heights. A 30% random holdout evaluation shows that the hybrid correction substantially reduces residuals within the screened GNSS/leveling network, decreasing the mean residual from −0.222 m to 0.003 m and the RMSE from 0.236 m to 0.041 m. The two geoid models were subsequently applied to a 20 m LiDAR-derived elevation dataset to evaluate their effects on orthometric-height conversion and coastal low-elevation classification. Although the broad pattern of coastal low-lands remains similar, local centimeter- to decimeter-level height differences can alter the classification of pixels near critical elevation thresholds, particularly in Taiwan’s flat western coastal plain. These results demonstrate that deformation-aware quality control of GNSS/leveling-derived geoid heights and hybrid geoid refinement are important not only for height modernization but also for reliable remote-sensing-based coastal elevation assessment. Full article

U.S. land-grant universities, with their campus departments, regional research centers, and county extension offices, play a unique role in promoting innovation in the circular bioeconomy. We examine various public–private R&D partnerships being undertaken by the University of Arizona to evaluate university roles in agricultural innovation. This study adapts Pray and Birner’s International Bioeconomy Innovation System (IBIS) framework to analyze regional innovation systems. The framework assesses systems in terms of the Public Research and Education Domain, Business Domain, Bridging Institutions, Demand for Innovations, Policies and Regulations, and Socio-cultural Factors. The framework is applied to projects including rural STEM (science, technology, engineering and math) training, vertical farming, aquaponics, microbial algae production, and food production in outer space. Projects emphasized introducing circularity in water-scarce production systems, reflecting regional resource scarcity. Supply chains are not linear with a single industry putting wastes to use in its own internal production. Rather, circularity means the creation of value webs where production processes span multiple value chains. This means introducing circularity is not just a bioengineering problem but also a marketing problem. Rural areas in Arizona face a bioeconomy workforce development dilemma where STEM-adept students tend to leave rural areas, while prospective employers may not locate in rural areas because of the lack of STEM-trained workers. A new federal-university program aims to break this cycle. Many of the case studies introduced circularity to meet environmental compliance goals or reduce carbon emissions. Greater consistency regarding climate change policy could bolster future bioeconomy development. Full article

The vertical redistribution of human activities and surface thermal changes poses challenges to Himalayan resilience. Using Nepal’s 77 districts, this study integrates land-use maps for 2000, 2020, and 2023 with annual MODIS land surface temperature (LST) data for 2000–2023. Trend analysis, fixed thermal thresholds, displacement correspondence tests, lag analysis, and GeoDetector were employed to examine land-use restructuring, thermal variability, and their spatial associations. Results show that: (1) Built-up land expanded from 527 to 1817 km², with its mean elevation increasing from 412 to 617 m. However, national mean LST, fixed-threshold hot-area extent, and hot-area mean elevation exhibited no significant monotonic trends. (2) Land-use and thermal displacements showed no consistent spatial correspondence or stable temporal lag, indicating regional vertical decoupling rather than delayed thermal migration. (3) Built-up expansion was positively associated with local LST trends. (4) Spatial associations between thermal heterogeneity and elevation, built-up land proportion, and population density, highlighting the spatial heterogeneity of topographic conditions and human activities in relation to regional thermal changes. These asynchronous vertical responses highlight potential development and ecological pressures in mid-elevation transition zones, suggesting a shift from predominantly horizontal spatial regulation toward elevation-sensitive, vertically adaptive planning for Himalayan resilience. Full article

Metro systems are expected to promote compact development, land-use diversity, pedestrian activity, and reduced automobile dependence, but these outcomes vary across station areas. This study examines how morphological, configurational, public-realm, behavioral, and governance conditions differ across three contrasting station-area transformation patterns during the planning and implementation of the Riyadh Metro. A comparative mixed-method case study examines Al Hamra, Granada, and the King Abdullah Financial District (KAFD), representing established suburban, commercial, and comprehensively planned high-density contexts. Methods combine GIS-based morphological comparison of two reference conditions, 2010 and 2023, Space Syntax and visibility analysis, field observation, photographic documentation, interviews, focus groups, and governance analysis. Because the 2023 condition predates passenger service, the comparison concerns station-area conditions during a period that overlapped metro planning and construction rather than the effects of an operating metro system. The design does not distinguish metro-related change from concurrent urban-development processes and therefore does not attribute the observed differences to the metro. Results show three contrasting empirical patterns: Al Hamra retained a corridor-dominant configuration with persistent lateral neighborhood discontinuities; Granada concentrated development and configurational prominence around established commercial destinations; and KAFD developed the most extensive formally connected network but with greater multi-level route complexity. Triangulation with field observations and participant evidence supported the interpretation of these patterns as Adaptive Retrofit, Commercial Convergence, and Programmed Vertical TOD Enclave, respectively. Full article

The paper presents the design, development, and simulation of an intelligent control system for the pitch-decoupled vertical takeoff and landing (VTOL) unmanned aerial vehicle (UAV). In contrast to conventional tilt-rotor VTOL UAVs, the mechanical structure of the pitch-decoupled VTOL UAV allows passive transition from vertical to horizontal flight modes, and vice versa, without the use of additional servo actuators. A detailed kinematic scheme and the dynamic equations of motion of the pitch-decoupled VTOL UAV equipped with a two-degree-of-freedom robotic arm are developed using Denavit–Hartenberg parameters and Euler–Lagrange equations. The aerodynamic stability of the UAV is investigated, and the aerodynamic coefficients used in the complete dynamics model are derived. On this basis, a multivariable control system is developed. To address the well-known transition-phase issues of VTOL UAVs, a neural controller is designed using the reinforcement learning actor-critic method. It is shown that the proposed neural controller enables a smooth and accurate transition phase and subsequent horizontal flight for the pitch-decoupled VTOL UAV. Full article

Loess landslides represent a severe geohazard in the Loess Plateau, posing significant challenges to sustainable development and regional safety. This study analyzed 111 landslides (1976–2018) and 529 marginal fissures in the South Jingyang Tableland (SJT) to reveal the distribution and failure modes of the landslide cluster. Preparation factors, including stratigraphic lithology, geomorphic features, and discontinuity systems (vertical/tectonic joints, unloading fissures, weak layers, and marginal fissures), were evaluated alongside triggering factors such as precipitation, irrigation, and river erosion. The main takeaways of this study are as follows. (1) A comprehensive database of 111 loess landslides (1976–2018) and 529 marginal fissures was constructed for the SJT, representing the longest and most complete chronological record available for this region. (2) Landslide activity within the Jiangliu landslide cluster (LC) exhibits an approximately decadal clustering pattern, with a temporal spacing of 9.6 ± 2.8 years between successive active periods, providing a basis for medium-term hazard forecasting in comparable settings. (3) The evolution of marginal fissures is controlled by the margin’s geometry and their interaction with slope failure processes, and the strong correlation between fissure development and landslide initiation enables the use of fissure monitoring as an early warning indicator. (4) The evolutionary mechanism follows a sequence of initial tectonic activity → rising groundwater → formation of the critical slide structure → water accumulation in fissures → single landslide → subsequent clustering. This process, termed a “water-induced loess catastrophe” (WILC), provides a conceptual framework for understanding landslide clustering on loess tablelands. (5) The database construction methodology, the decadal clustering analysis, and the WILC model collectively offer transferable tools for medium-term hazard forecasting, fissure-based early warning, and sustainable land-use planning on loess tablelands, not only in the SJT, but also in other loess regions with similar geological and hydrological settings. Full article

Carbon fiber reinforced polymer (CFRP) is extensively utilized in aerospace, transportation, and particularly in the rapidly evolving low-altitude economy sector represented by unmanned aerial vehicles and electric vertical take-off and landing aircraft. However, laser drilling of CFRP presents significant challenges, especially in processing deep micro-holes, due to pronounced thermal effects and hole taper. In this study, a picosecond fiber laser beam was directed into a spiral scanning machining head to establish a precision micro-hole machining system. A two-step machining strategy assisted by high-pressure compressed air was proposed: the first step employs full spiral scanning for efficient through-hole drilling, while the second step utilizes half spiral scanning to form near-zero taper circular holes. The through-hole generated in the first step facilitates the passage of high-pressure assist gas, effectively removing ablation debris and providing cooling to the inner wall. Circular holes with a diameter of 400 μm and an aspect ratio of 5:1 were successfully fabricated on CFRP with high efficiency. Both the hole entrance/exit and the inner wall exhibited excellent quality: the heat-affected zone width at the entrance was 8.1 μm, with a taper as low as 0.0045. The inner wall was extremely smooth, featuring an average roughness of 0.379 μm. The fibers and resin remained tightly bonded, and the material structure at the fiber ends was well preserved. The system demonstrated high processing efficiency and excellent consistency in fabricating deep micro-hole arrays, indicating strong potential for industrial applications. Full article

Long-term monoculture management of plantation forests has caused declining soil fertility and biodiversity loss, a key bottleneck for sustainable forestry. Understory cultivation of medicinal plants, forming a multi-layered vertical structure, offers a promising pathway to improve land-use efficiency while balancing ecological protection and economic benefit. Using the framework “plant functional traits–soil processes–ecosystem functions,” this paper examines how forest–medicinal plant agroforestry systems affect soil quality and the understory environment. Aboveground traits (specific leaf area, leaf dry matter content) regulate soil carbon stability via litter input, while belowground traits (root architecture, exudates) drive soil structure and nutrient cycling through rhizosphere effects. These systems optimize soil pore structure through root penetration, influence organic matter accumulation via litter decomposition and root carbon input, and enhance nutrient availability via mycorrhizal symbiosis and organic acid secretion. However, poor long-term management may cause acidification, nutrient imbalance, and replant problems. Diversified carbon inputs also reshape microbial community structure, functional genes, and enzyme activities, while enhanced plant diversity regulates understory microclimate (light, temperature, moisture). Finally, the paper outlines future research directions and proposes a core “context-dependency” hypothesis, emphasizing that effect direction and intensity are nonlinearly modulated by forest type, medicinal species, and management duration. Full article

Ground-based monitoring networks often provide uneven spatial coverage, limiting the characterization of air-quality in heterogeneous regions. This study proposes a data-driven framework that identifies spatially coherent atmospheric regimes from multi-gas satellite observations. The framework is applied to investigate the seasonal distribution of PM_2.5-related trace-gas indicators and aerosol loading over the Lazio region, central Italy, using TROPOMI-derived vertical column densities of NO₂, HCHO, and CO products together with MODIS-MAIAC Aerosol Optical Depth, and integrating satellite observations with land-cover, topographic, and ground-based NO₂ data. In this approach, TROPOMI provides spatially continuous information on atmospheric composition, unsupervised clustering identifies multi-gas patterns, and land information supports the interpretation of drivers of emission. The seasonal analysis showed winter NO₂ maxima associated with combustion-related emissions, urban areas, and transport corridors, while HCHO peaked during summer, reflecting enhanced VOC-related photochemical activity. CO displayed a more diffuse spatial distribution, consistent with its longer atmospheric lifetime and broader combustion-related sources. The multivariate classification highlighted the Sacco Valley as a multi-pollutant area, the Tiber Valley as a peri-urban agricultural corridor, and the Lepini Mountains as a cleaner sector. The proposed framework provides spatially explicit information useful for interpreting regional air-quality variability, identifying under-monitored sectors, and supporting monitoring and mitigation strategies. Full article

The Louis Botha Transit-Oriented Development (TOD) was introduced to address apartheid-era urban fragmentation. However, the extent to which the TOD initiative has translated into tangible built-form outcomes remains unclear. This study empirically evaluates TOD performance along the Louis Botha Corridor, covering eight precincts along the 13.16 km stretch. The precincts include Hillbrow, Berea, Orange Grove, Highlands North, Balfour, Bramley, Wynberg, and Marlboro. The measurable parameters are Building Footprint Density (BFD), Floor Area Ratio (FAR), land-use composition, and transit accessibility. The results show a corridor-wide average BFD of 0.2689 and average FAR of 0.5046, indicating moderate but uneven development intensity. Wynberg emerges as the highest-intensity node, (BFD 0.4049 and FAR 0.8196), while Hillbrow exhibits strong vertical intensification with a high FAR of 0.7098 despite a lower BFD (0.1925). In contrast, Marlboro, Berea, Balfour, Orange Grove, and Highlands North have a FARs below the corridor average of 0.5046. Land-use analysis reveals a corridor-level balance (53.14% residential, 44.40% non-residential); however, at the precinct level, monofunctional use prevails, with residential dominance in Orange Grove (87.96%), Highlands North (79.39%), and Berea (75.86%). Transit accessibility analysis indicates inconsistent station spacing (mean = 1.68 km; SD = 0.75 km), with about 87.51% of walking distances exceeding 400 m, which exceeds recommended TOD thresholds. The findings underscore the need for precinct-specific densification policies and stronger coordination between transit investment, development control, and urban governance to achieve more inclusive, transit-supportive urban growth. Full article

Vertical profiles of eddy dissipation rate (EDR) are obtained for the first time in Hong Kong by a network of Doppler LIDAR systems in the territory. The method of calculation of the EDR from LIDAR system data is reviewed. The results of measurements are analyzed. A strong southerly wind case and two strong easterly wind cases are considered. The measured EDR profiles seem to be related to mechanical turbulence due to local terrain. However, by comparison between measured EDR profiles and the simulated EDR profiles from a high resolution mesoscale meteorological model, it appears that local land use also affects the EDR measurements, which may have a representativeness issue for the turbulence in a region around the measurement site. Application values of such measurements and future research directions are discussed in this paper. Full article

Out-of-hospital cardiac arrest (OHCA) remains one of the leading causes of death worldwide, with patient survival strongly dependent on rapid defibrillation. Although unmanned aerial vehicles (UAVs) have recently been investigated for Automated External Defibrillator (AED) delivery, the existing solutions are predominantly based on low-speed multirotor platforms with limited operational range and cruise velocity. This paper presents the conceptual development and preliminary analyses of a high-speed VTOL tailsitter UAV intended for rapid AED delivery missions. The proposed flying-wing platform combines vertical take-off and landing capability, hover flight during payload deployment, and cruise flight at 160 km/h. The work includes initial design assumptions, mission profile definition, and preliminary propulsion-related analyses forming part of a broader UAV development project conducted at Wrocław University of Science and Technology. The presented study addresses the technological gap in high-speed medical UAV platforms capable of combining efficient forward flight with precise hover capability for emergency-response applications. Full article

Visitors encounter museums through movement, as galleries, routes, and levels become visible and accessible from successive bodily positions. Yet, stair approaches, landings, balconies, and gallery thresholds are often treated as residual connectors rather than as spaces that help stage museum sequences. This study examines that role through eight selected liminal conditions at Steven Holl’s Kiasma Museum of Contemporary Art, Helsinki: four spiral-linked spaces, two atrium balconies, and two gallery thresholds. Grounded in embodied, ecological, and enactive accounts of perception, the study analysed eight paths using sequential isovist profiles interpreted alongside plans, sections, and observations. The transitions reorganise visibility and locomotor access in distinct ways along the route rather than sharing a common metric pattern. Spiral-linked spaces relate local movement to a recurring vertical circulation system, balconies provide visual relations across levels while withholding direct movement between them, and gallery thresholds withdraw one gallery setting and establish another progressively or abruptly. These findings show that spaces commonly treated as circulation can prepare, connect, separate, withdraw, and disclose successive museum settings. Sequential isovist analysis describes how this configurational work unfolds, specifying permanent environmental conditions relevant to embodied spatial cognition and to museum and exhibition sequencing, without taking geometry as evidence of experience or curatorial intention. Full article

Canal heritage settlements in the Jiangnan water-network region constitute a built-environment legacy of sustained, long-term human–water co-adaptation, yet their traditional morphologies and spatial fabrics are undergoing rapid restructuring amid accelerated industrialization and urbanization. Existing analytical approaches remain largely confined to two-dimensional buffer-zone analysis and planar kernel-density estimation, which cannot distinguish whether contact relationships among historical layers represent conformable contacts or angular unconformities, and have failed to translate geological stratigraphic succession into an operational framework for built heritage conservation. Drawing on landscape stratigraphy theory, this study converts historical layering, path dependency, and spatial inheritance into quantifiable GIS indicators, employing an extrusion index, a path-dependency index, a Gaussian residual field model, and Geodetector factor-interaction analysis to interrogate spatial evolution mechanisms. Most settlements exhibit stable stratigraphic layering, while a subset display angular unconformity linked to institutional displacement events and others demonstrate structural wedging toward canal frontages driven by commercial densification. Commercial points of interest retain the strongest clustering lock-in on historical waterway networks, while transportation points of interest remain linearly constrained along the historical canal corridor. Archaeological remnants remain significantly spatially coupled with contemporary land-use patterns through residual field effects even after abandonment or functional weakening. Water-network density and historical period exhibit enhanced synergistic effects on settlement spatial differentiation. These findings indicate that the spatial evolution of canal heritage settlements follows a stratigraphic logic, in which the vertical embeddedness of historical infrastructure is associated with the horizontal elasticity of contemporary spatial responses. The proposed metrics furnish replicable quantitative tools for heritage zoning and sustainable conservation planning. Full article