Urban Terrain Research Articles

Comparative study on deep and machine learning approaches for predicting wind pressures on tall buildings

Wind-structures interaction has been extensively examined in the last few decades using field measurements, full scale measurements and wind tunnel testing. These experimental approaches are considered costly and time consuming. The need for a reliable analytical approach that can be used for examining wind-effects on buildings is clear. Although Computational Fluid Dynamics (CFD) is one of the other alternative numerical options yet might not reached the level of confidence to be reliably used to finalize the structural design. On the other hand, a limited number of studies have been carried out using soft computing methods to examine wind-induced loads on structures. However, its promising results, more work is still required towards achieving the full analytical prediction of wind effects on structures. This study investigates the use of different soft-computing techniques in predicting wind pressures on tall buildings. Two deep learning methods viz deep belief network (DBN) and deep neural network (DNN), and five machine learning methods namely feedforward neural network, extreme learning machine, weighted extreme learning machine, random forest, and gradient boosting machine were evaluated, and compared in predicting the design wind pressures on tall buildings. Wind tunnel datasets, used in the current study to develop the proposed computing models, were collected from testing three tall buildings having the same full-scale horizontal dimensions of (40 m and 80 m) and different heights of (80 m, 120 m and 160 m). The buildings were tested at a scale of 1:400 in urban terrain exposure. Mean and fluctuating wind pressure coefficients on the building with the height of 120 m are herein predicted using the seven computing methods and the results were compared to the corresponding measured pressures. Overall, the examined methods performed well in the wind pressure prediction process. Furthermore, the employed DNN was found to have the best performance in predicting mean and fluctuating wind pressures with the highest correlation coefficients. Hence, the DNN was also used in predicting the mean and fluctuating wind pressures on the two other buildings with heights of 80 m and 160 m. Experimental results indicate that the employed DNN model can be effectively used in predicting wind-induced pressures on tall buildings.

Effects of Attached Afterbody Shapes on Wind Forces on Rectangular Tall Buildings

ABSTRACTThe knowledge of aerodynamic forces has important implications for the wind‐resistant design of tall buildings. At present, the aerodynamic characteristics of conventional rectangular‐shaped tall buildings have been extensively studied, while those of irregular‐shaped tall buildings have received relatively less attention. Therefore, in the current study, several tall building models are designed to investigate the aerodynamic characteristics of a rectangular tall building with and without attaching different shapes of afterbody. The influences of the afterbody shapes (i.e., semicircle, rectangle, and triangle attached to a rectangular tall building called the basic model in this paper), atmospheric boundary layer (ABL) flows, and models' aspect ratios on the aerodynamic forces are analyzed and discussed in detail based on wind tunnel test of pressure measurements on the models. It is shown that the attached afterbodies can significantly increase the local fluctuating lift coefficients and base fluctuating moment coefficients comparing to those of the basic model. Moreover, a larger aspect ratio causes the increase of local fluctuating lift coefficients and base fluctuating moment coefficients of the basic model attached with rectangular afterbody in suburban terrain. On the other hand, the above increases are strongly attenuated or even suppressed by the ABL flow over urban terrain. The results of this study are expected to provide useful information for the wind‐resistant design of irregular‐shaped tall buildings.

An improve crested porcupine algorithm for UAV delivery path planning in challenging environments

With the rapid advancement of drone technology and the growing applications in the field of drone engineering, the demand for precise and efficient path planning in complex and dynamic environments has become increasingly important. Traditional algorithms struggle with complex terrain, obstacles, and weather changes, often falling into local optima. This study introduces an Improved Crown Porcupine Optimizer (ICPO) for drone path planning, which enables drones to better avoid obstacles, optimize flight paths, and reduce energy consumption. Inspired by porcupines' defense mechanisms, a visuo-auditory synergy perspective is adopted, improving early convergence by balancing visual and auditory defenses. The study also employs a good point set population initialization strategy to enhance diversity and eliminates the traditional population reduction mechanism. To avoid local optima in later stages, a novel periodic retreat strategy inspired by porcupines' precise defenses is introduced for better position updates. Analysis on the IEEE CEC2022 test set shows that ICPO almost reaches the optimal value, demonstrating robustness and stability. In complex mountainous terrain, ICPO achieved optimal values of 778.1775 and 954.0118; in urban terrain, 366.2789 and 910.1682 and ranked first among the compared algorithms, proving its effectiveness and reliability in drone delivery path planning. Looking ahead, the ICPO will provide greater efficiency and safety for drone path planning in navigating complex environments.

The last cityscapes: public cemetery management in Kumasi’s Urban Terrain

ABSTRACT Land is inelastic in supply. The judicious use of land within the urban land space is thus critical. Regrettably, little research has been done on planning and managing public cemeteries in Kumasi, Ghana. This study, incorporating insights from four public cemeteries and feedback from 79 participants, assesses the legislative and policy frameworks governing cemetery management in Kumasi. It also examines the condition of these cemeteries and identifies the challenges to their proper upkeep. Data were gathered through structured interviews and direct observation and were analysed thematically. Findings indicate that cemetery management in Kumasi is a collaborative task between Traditional Authorities and the local government, each operating under their respective but similar laws. Some of these cemeteries need more essential facilities, making them substandard in their current state, primarily due to financial limitations that impede effective management. This study makes recommendations to guide the effective and sustainable management of public cemeteries in Kumasi and beyond.

Revolutionizing Urban Pest Management with Sensor Fusion and Precision Fumigation Robotics

Effective pest management in urban areas is critically challenged by the rapid proliferation of mosquito breeding sites. Traditional fumigation methods expose human operators to harmful chemicals, posing significant health risks ranging from respiratory problems to long-term chronic conditions. To address these issues, a novel fumigation robot equipped with sensor fusion technology for optimal pest control in urban landscapes is proposed. The proposed robot utilizes light detection and ranging data, depth camera inputs processed through the You Only Look Once version 8 (YOLOv8) algorithm for precise object recognition, and inertial measurement unit data. These technologies allow the robot to accurately identify and localize mosquito breeding hotspots using YOLOv8, achieving a precision of 0.81 and a mean average precision of 0.74. The integration of these advanced sensor technologies allows for detailed and reliable mapping, enhancing the robot’s navigation through complex urban terrains and ensuring precise targeting of fumigation efforts. In a test case, the robot demonstrated a 62.5% increase in efficiency by significantly reducing chemical usage through targeted hotspot fumigation. By automating the detection and treatment of breeding sites, the proposed method boosts the efficiency and effectiveness of pest management operations and significantly diminishes the health risks associated with chemical exposure for human workers. This approach, featuring real-time object recognition and dynamic adaptation to environmental changes, represents a substantial advancement in urban pest management, offering a safer and more effective solution to a persistent public health issue.

DualNet-PoiD: A Hybrid Neural Network for Highly Accurate Recognition of POIs on Road Networks in Complex Areas with Urban Terrain

DualNet-PoiD: A Hybrid Neural Network for Highly Accurate Recognition of POIs on Road Networks in Complex Areas with Urban Terrain

Holy Infrastructures: Catholicism, Detroit Borderlands, and the Elements

Abstract Through an ethnographic rendering of the Catholic Church at the Detroit-Windsor borderland, this article foregrounds the ways elemental forces, including water, earth/soil, and air, form an interconnected entity that constitutes part of the theopolitical and religious scaffolding of Holy Infrastructures. We argue that the repetitive inscription of social and affective flows within an urban terrain generates infrastructure projects that contract forces of variable intensity into alliance or disjuncture. The interrelation of these forces as Holy Infrastructure, offers vital information on (dis/en)abling racialized forms of hosting and being hosted by the divine within urban settings, specifically as it pertains to theological labor at multiple scales. Indeed, we understand holiness in Catholic Detroit as a performative sovereignty of partition that mediates a desire for unbrokenness and spatiotemporal rapture. The topologies of Holy Infrastructure thus give rise to overlapping but divergent “wholes” within the racialized urban terrain, offering insight into the Church as a loose network of horizontal alliances that may enforce or subvert hierarchy. Our focus on elemental forces allows us to move beyond abstractions and focus on how theological projects take shape in physical space within an urban ecology. Indeed, Holy Infrastructures come into focus most clearly in relation to the intersection of theology with environmental, climatic, and territorial projects. By approaching Church and State as co-constitutive, we show how Holy Infrastructures offer insight into the racialized and gendered terrain of contemporary Detroit.

Model Analysis Principles for the Design of Public Spaces in Bistrița-Târgu Mureș Urban Axis

Model Analysis Principles for the Design of Public Spaces in the Bistrița-Târgu Mureș Urban Axis. The physical urban terrain across cities continually evolves through insights, consultations, deliberate redesigning or random acts by community members and natural forces that reshape the urban landscapes and how urban spaces are used. This research establishes a set of normative principles that planners and others can use when planning and regulating the design and management of public space. Data were collected in the period March 2023 – January 2024. Based on a comprehensive analysis of public space in the city, the paper sets out a number of general principles relating to the essential, but often missing, strategic planning framework for developing and regenerating public spaces, providing seven more detailed considerations for assessing the quality of public space design and a proposal for spatial planning. This is an unreservedly positive framework for shaping public space, based on the idea that public spaces in our cities come in many different shapes and forms, but that together they add immense value to the experience and potential of urban areas. The research takes place in the Bistrița-Târgu Mureș urban axis, the field research carried out as part of the study results in a set of three principles of urban spatial planning that examine proposals for the design of public spaces. Keywords: public space, design principles, planning, Bistrița-Târgu Mureș urban axis

Impact of natural urban terrain on the pedestrian wind environment in neighborhoods: A CFD study with both wind and buoyancy-driven scenarios

The impact of topography on airflow has been studied at different scales, however the influence of urban natural terrain on local wind conditions is unclear. In this study, the impact of natural urban terrain on mean wind speed at the pedestrian level is investigated. A numerical study is conducted using a Large Eddy Simulation (LES) model for a high-density residential neighbourhood in Singapore with the natural terrain and a flat surface. The following two wind variations are examined (1) low wind speed and high temperature conditions for which the atmospheric boundary layer exhibits unstable thermal stratification; (2) annually averaged wind conditions with neutral thermal stratification. The results show that the overall impact of natural urban terrain on pedestrian wind speed is pronounced when the wind environment exhibits unstable thermal stratification i.e. buoyancy driven flows, compared with wind driven flows. For both cases, the results indicate a localized effect based on building density and proximity to steep terrain with spatial averages as high as approximately 0.8 m/s. In areas characterized by low density, fewer surrounding buildings, or open spaces, it is advisable to model the topography when it is shallow or steeply sloping. For medium density built areas, natural urban terrain modelling is also recommended. However, it is observed that in a high-density region, pedestrian wind flow is more strongly affected by the surrounding buildings than the terrain. These results are potentially important to balance computational cost and accuracy in urban wind simulations in urban areas with various densities and microclimate scenarios.

Relevance of IPR in Small Businesses

Small businesses in India have always been one of the major occupations in rural as well as urban terrain and they are major source of income for the middle class group. As urbanization has increased the demand for the small services like grocery shops, bakeries, vegetable shops, laundry shops, juice centers, sweet shops, small hotels etc. Majorly the urban population is a mix of all the classes of people but a considerable portion is occupied by the middle and low income group, which has resulted in requirement of small services, and retail shops. As of a result of which the small businesses mushroom in the different localities, in different sizes so that they can cater to all the segments of consumers. Small business organizations contribute to the economy significantly by distributing the finished goods to the ultimate consumers, and they also create jobs in smaller units. The large business organizations contribute to economy by creating jobs in a bulk, economies of scale. The large scale organizations have the accessibility to hire legal professionals like legal advisers and naturally they give the suggestions on legal aspects for a smooth conduct of the business. In this context large or medium sized organizations have proximity to legal protection for their inventions, design, copyrights, trademarks etc, and they consciously protect their rights by patents or trademark and so on. In this article we have made an attempt to understand the extent of application of IPR in small and micro businesses.

Depolarization effects when receiving radio waves on a moving object for various types and characteristics of the path

Depolarization is a change in the plane of oscillation of the vector of an electromagnetic wave during its propagation. It is important to take into account the depolarization of electromagnetic waves when designing a radio path, since each component (vertical and horizontal), depending on the propagation conditions, will have its own attenuation coefficient. In this regard, the choice of one or another type of polarization (linear, circular and elliptical) for a specific radio path will have a significant impact on the level of the received signal. In the course of this work, the most significant factors leading to the depolarization of electromagnetic waves along the propagation paths were identified. These factors included: scattering on bodies of suburban terrain (ground, forests, etc.), reflections (in combination with multipath propagation) from bodies of urban terrain, random (inclined) position of the antenna mobile terminal, Faraday rotation and dispersion in precipitation. As a result of the analysis of depolarization factors, mathematical models were formed that, due to their applied nature, made it possible to predict the effect of depolarization on the quality of reception by a subscriber station installed on a moving object, and also showed the relevance of using antenna systems with automated polarization adaptation.

Empowering more balanced energy futures: The role of the digital economy in alleviating China's energy trilemma at the city-level

This study explores the influence of the Digital Economy (DE) on the Energy Trilemma (ET) across Chinese cities from 2008 to 2021. Leveraging an extensive panel dataset encompassing 276 cities, we constructed a city-level ET index, categorized cities using k-means clustering, and employed IV-GMM regression to scrutinize the impact of DE. Our findings reveal that DE is instrumental in tackling ET issues, with significant variations attributed to city-specific attributes, including centralized heating systems and the complexity of urban terrain. The mediation analysis pinpoints the optimization of industrial structures, technological progress, and the attraction of foreign investment as key conduits through which DE exerts its influence on ET. These insights highlight the pivotal role of DE as an essential instrument for bolstering sustainable energy frameworks. They also emphasize the necessity for city-specific digital economy policies to effectively address the unique ET challenges faced by each municipality. Additionally, the study underscores the positive influence of openness to foreign investment in the energy sector as a strategy for confronting ET challenges.

Policing, Power, and Protests: Landscapes of Surveillance in Private and Public Spaces in Lower Manhattan

In decades since 11 September 2001 (9/11), surveillance and policing within the United States have increased manifold and, with them, protests against the systemic racism and classism embedded in these practices. These practices go back beyond the 21st century—these modes of policing, power, and protests against them are not new. Due to urban spaces’ concentration of political, economic, and social power and the sheer density of people, they can quickly take on material and symbolic importance that can last for centuries. As public protests increase, so do countermeasures from those wielding power in the forms of both formal and informal policing and surveillance. These policing measures also leave material traces in the landscape, working to create a palimpsest of trauma across urban terrains. The lineage of a surveillance landscape as seen in policing, power, and protest in Lower Manhattan, will be explored through a documentary archaeological approach to examine the residual trauma left in public spaces.

Numerical and Analytical Estimation of the Wind Speed Causing Overturning of the Fast-Erecting Crane—Part II

The currently presented work is a continuation of the previous one, where the estimation of the forces induced by the wind flow acting on the fast-erecting crane. In that work, the values of the aerodynamic forces were determined experimentally and numerically for the sectional models of the tower and jib. Next, the obtained results were compared with the appropriate standards. Now, the main aim is to determine the critical wind speed causing the overturning of the whole structure. At the very beginning, the numerical analysis of the simplified model of the crane on the real scale is studied. The computations are performed with the use of the ANSYS FLUENT R22. The simulations are performed for three different wind profiles, namely: urban terrain, village terrain, and open terrain. Moreover, the various geometric configurations of the crane in the wind direction are studied. The k-ε model of turbulent flow is exploited. The obtained critical values of the wind speed are confronted with those that are obtained from standards and estimations based on the results obtained from previous investigations performed for sectional models. The influence of the load carried by the crane is also taken into consideration in the overturning of the structure.

Advancing rapid urban flood prediction: a spatiotemporal deep learning approach with uneven rainfall and attention mechanism

ABSTRACT Urban floods pose a significant threat to human communities, making its prediction essential for comprehensive flood risk assessment and the formulation of effective resource allocation strategies. Data-driven deep learning approaches have gained traction in urban emergency flood prediction, addressing the efficiency constraints of physical models. However, the spatial structure of rainfall, which has a profound influence on urban flooding, is often overlooked in many deep learning investigations. In this study, we introduce a novel deep learning model known as CRU-Net equipped with an attention mechanism to predict inundation depths in urban terrains based on spatiotemporal rainfall patterns. This method utilizes eight topographic parameters related to the height of urban waterlogging, combined with spatial rainfall data as inputs to the model. Comparative evaluations between the developed CRU-Net and two other deep learning models, U-Net and ResU-Net, reveal that CRU-Net adeptly interprets the spatiotemporal traits of rainfall and accurately estimates flood depths, emphasizing deep inundation and flood-vulnerable regions. The model demonstrates exceptional accuracy, evidenced by a root mean square error of 0.054 m and a Nash–Sutcliffe efficiency of 0.975. CRU-Net also accurately predicts over 80% of inundation locations with depths exceeding 0.3 m. Remarkably, CRU-Net delivers predictions for 3 million grids in 2.9 s, showcasing its efficiency.

Fast iterative shooter localization in urban terrain using ray casting.

This study presents a method for real-time capable localization of impulsive acoustic events in urban terrain, omitting the need for precomputation phases, such as in time matching or impulse response matching. Using ray casting, solutions of the wave equation are computed using a boundary discretization of intersected objects, forming a weighted graph using line of sight checks, and deploying an A* search graph traversal algorithm for the calculation of the propagation time. Subsequently, the wave amplitude along the identified eigenrays is computed. The study discusses the properties and suitability of cost functions based on time differences of arrival, amplitude differences of arrival, and a combined cost function for iterative ray-based localization. The method is validated using pressure data of the muzzle blasts of various firearms collected via unattended ground sensors during an experimental campaign at the military urban combat facility in Walenstadt, Switzerland.

Data driven assessment of rock mass quality in red-bed hilly area: a case study of Guang’an city, SW China

The evaluation of geological suitability for urban underground space (UUS) development is an indispensable prerequisite for its optimal utilization. As the actual carrier of underground facilities, the evaluation of rock mass quality plays a crucial role in assessing geological suitability. However, it is notable that the evaluation of rock mass quality has regrettably remained somewhat marginalized within the broader framework of the geological suitability assessment in recent years. The selection of pertinent indicators for the evaluation of rock mass quality inherently presents an appreciable degree of subjectivity. Predominantly subjective evaluation methods continue to dominate the field, while the application of objective algorithms, such as unsupervised clustering, remains in its nascent stage. Furthermore, there is a lack of comprehensive investigations into distinct combinations of attributes. This limitation confines the broader applicability of the evaluation outcomes in the context of urban underground space. Within this study, we meticulously amassed rock core test data from over 40 boreholes of engineering geological significance within the urban planning ambit of Guang'An City. Utilizing the K-means unsupervised clustering algorithm and the Principal Component Analysis (PCA) algorithm. We successfully conducted an unsupervised clustering procedure with nine distinct physical and mechanical attributes. This yielded an aggregation into five discernible clusters. Building upon the derived clustering outcomes, a stratification of rock mass quality was effectuated into three distinct tiers: Level 1 (characterized by pure sandstone), Level 2 (primarily dominated by sandstone), and Level 3 (denoting fair conditions predominantly influenced by mudstone). This structured stratification facilitates a relatively objective and comprehensive evaluation of rock mass quality within the context of the red-bed hilly terrain. In the course of this analytical trajectory, we conducted a dissection of the clustering efficacy. For strongly correlated attributes, we propose a preliminary dimensionality reduction procedure prior to the clustering endeavor. Moreover, we recommend intervals of 10 m for the stratified evaluation in red bed hilly urban terrains.

Bombay cinema’s mapping impulse: Location, suspense and atmosphere

This article examines the use of locations in a cross-section of contemporary Bombay films. The complicated workings of various kinds of production infrastructures typically shape cinema’s topographical motivations and sense of scale. Through a comparative analysis of films shot in and around Bombay with a film shot in a location outside India, I establish how the aesthetic drives of vertical, horizontal and atmospheric urbanism have generated a cartographic diversity in the cinematic imagination of contemporary India. The focus is on suspense films and their creative use of location shooting to invoke physical and psychological expressions of space. These are small-budget films where scale and navigational possibilities are managed carefully. In Anurag Kashyap’s Ugly (2013), the hunt for a kidnapped child unveils a gritty urban terrain and the failed dreams of its damaged protagonists. Vikramaditya Motwane’s Trapped (2016) showcases the slow breakdown of a man who inadvertently gets locked into an apartment on the 35th floor of an empty, half-constructed, high-rise building with no electricity, food or water. Unlike Ugly and Trapped, which speak to Bombay’s constant play with feelings of desperation and survival, Badla (2019) transports us to the cold, wintry landscape of Scotland to create an atmosphere for a psychological exposition of crime and revenge.

Community-Scale Classification and Governance Policy Implications for Demographic, Economic, and Land-Use Linkages in Mega-Cities

Analyzing the spatio-temporal relationship between socio-economics and land-use structure at the micro-scale is crucial for effective spatial governance in large cities. This paper focuses on Beijing, utilizing long time-series remote sensing images and multi-source data spanning 30 years. We employ spatio-temporal clustering based on kilometer grid cells and a community-scale multi-factor aggregation method to categorize the linkages and spatio-temporal matching of population, GDP, land development, and ecological protection at the community level in a problem-oriented approach. Results indicate significant changes in Beijing’s population, GDP, and land use, with a 11.53% increase in land development intensity. We identify significant temporal and spatial disparities between population–GDP dynamics, population–land development trends, and GDP–land development patterns, underscoring the multifaceted challenges inherent in urban governance. Areas characterized by lagging population concentration, sluggish economic growth, rampant land development, and ecological fragility collectively encapsulate notable portions of Beijing’s expansive urban terrain. Mismatches pose governance risks, with medium to high-risk communities comprising 18.08% of community units and high-risk types representing 4.27% in Beijing. These discrepancies pose formidable governance risks, with communities ranging from moderate to high-risk categories, necessitating tailored interventions to address their unique challenges. This systematic exploration of comprehensive governance issues within mega-cities promises to furnish decision-makers with invaluable insights, facilitating nuanced and strategic urban governance approaches tailored to the intricacies of urban dynamics and challenges.

Across-wind response characteristics of tall-square towers in urban flow: An experimental study focused on the aeroelastic effects

To fully use the land resource in the urban regions of metropolises, high-rise buildings of large aspect ratio maybe preferred for the new constructions. To systematically investigate the across-wind responses of these quite slender structures, the urban boundary layer flow of high turbulence intensity was simulated in the wind tunnel, and aeroelastic tests realized by the pivot model setup were carried out for the square cross section towers of various heights resulting in large aspect ratios (λ = 12, 16, 20). No appreciable aeroelastic behaviors have been observed for the λ = 12 tower even for a very low damping ratio (0.57%). This is in line with the many previous studies for the tall-square tower with an aspect ratio not higher than 10, likely due to the very high turbulence intensity in the urban terrain, mitigating the occurrence of possible aeroelastic behaviors. In contrast, the λ = 16 and (especially) the λ = 20 towers exhibit strong oscillations known as the across-wind galloping, evidenced by the monotonic increase in the amplitude–velocity curve and the clear characteristics of simple-harmonic oscillations. Moreover, it is observed that for a certain range of low damping ratios, these large oscillations were initiated at the same wind speed very close to the vortex-resonance wind speed. The interaction mechanism between vortex induced vibration and galloping is thus supposed responsible for this observation (even in urban flow). Finally, peak across-wind responses at various damping ratios were provided as well, serving as a useful reference for the future design of similar tall-square towers.