Real Urban Environment Research Articles

Impacts of building modifications on the turbulent flow and heat transfer in urban surface boundary layers

This study examines turbulent airflow and upward heat transport in real urban environments using a building-resolving large-eddy simulation model to understand the characteristics of turbulent airflow and upward heat transport when geometrical distributions of buildings are modified. The target areas were two real urban districts within Osaka City, Japan, having different morphological features. In the numerical experiments, the initial condition was set to a neutral condition in which temperature is uniformly distributed vertically, and buildings emitted heat at a constant rate. The results in the two districts indicated that the features of turbulence and heat transport distinctly differed with different building arrangement. Specifically, taller buildings significantly decelerated airflows and induced warming behind buildings. More high-rise buildings (which resulted in a larger building variability) in a district with a larger building density caused a large heat flux and warming at higher levels. The sensitivity experiments in which a density and height variability of buildings were modified showed that a building density at higher levels and a building height variability significantly influenced warming at upper levels. An increased building height variability weakened wind speed and disturbed horizontal heat advection, whereas a large building density caused numerous heat sources.

Cities in electronic games: how they present and impact real urban areas?

ABSTRACT This study investigates the interactions between virtual cities in electronic (video) games and real urban environments, highlighting a significant gap in the literature regarding the influence of real cities on virtual counterparts and vice versa. Drawing on classical urban theories, it sets two primary objectives: to systematically review how real cities are represented in games and to explore the impacts of virtual cities on real urban areas. Through typological analysis, it identifies two pathways – form and function – through which real cities manifest in games, using specific cases like Cities: Skylines to illustrate these pathways. The principle for virtual city design is also outlined, with an emphasis on the “selection” and “subtraction” of real urban elements in designing processes. Additionally, it discusses how virtual cities impact urban tourism, fostering phenomena like anime pilgrimages, and urban planning, and enhancing public engagement in planning processes. Finally, this research contributes to some newly emerging theories such as Digital Twins by elucidating the interactive relationship between physical and virtual urban spaces.

The Development of a Prototype Solution for Detecting Wear and Tear in Pedestrian Crossings

Crosswalks play a fundamental role in road safety. However, over time, many suffer wear and tear that makes them difficult to see. This project presents a solution based on the use of computer vision techniques for identifying and classifying the level of wear on crosswalks. The proposed system uses a convolutional neural network (CNN) to analyze images of crosswalks, determining their wear status. The design includes a prototype system mounted on a vehicle, equipped with cameras and processing units to collect and analyze data in real time as the vehicle traverses traffic routes. The collected data are then transmitted to a web application for further analysis and reporting. The prototype was validated through extensive tests in a real urban environment, comparing its assessments with manual inspections conducted by experts. Results from these tests showed that the system could accurately classify crosswalk wear with a high degree of accuracy, demonstrating its potential for aiding maintenance authorities in efficiently prioritizing interventions.

Greener view, safer drive: Using repeated field experiments and deep transfer learning technique to investigate impacts of urban road landscapes on driving performance

Driving in urban environments is an essential part of urban residents’ daily life. We still know little about impacts of a wide range of greenness on driving performance in real urban environments, after controlling for socioeconomic, demographic, driving record, and other environmental factors. This missing knowledge prevents policymakers and professionals from using appropriate planning and design of green landscapes to create safe driving environments for numerous urban residents. This study aimed to address this significant knowledge gap by using real-world driving experiments. Each of thirty-four residents performed seven driving tasks so 238 driving tasks were completed in total. Each task lasted one hour and followed a randomly assigned sequence. Road greenness and other environmental characteristics were analyzed using deep transfer learning semantic segmentation based on live videos (30 frames per second), recorded by a camera positioned to capture the driver’s eye view. A serial communication technology, known as Controller Area Network bus (CANbus), was employed to continuously measure driving performance using four parameters. A series of hierarchical regression analyses yielded three major findings: First, an increased mean of greenness was associated with improved driving performance, as demonstrated by all four parameters. Second, an increased variation of greenness was also associated with better driving performance in three parameters. Finally, the mean of greenness displayed a stronger positive relationship with driving performance than the variation of greenness in three parameters. The findings imply that both the quantity and quality of green landscapes are critical for promoting driving performance in urban areas.

Large-eddy simulation of aerosol concentrations in a realistic urban environment: Model validation and transport mechanism

Air pollution in urban environments exhibits large spatial and temporal variations due to high heterogeneous air flow and emissions. To address the complexity of local air pollutant dynamics, a comprehensive large-eddy simulation using the PALM model system v6.0 was conducted. The distribution of flow and vehicle emitted aerosol particles in a realistic urban environment in Malmö, Sweden, was studied and evaluated against on-site measurements made using portable instrumentation on a spring morning in 2021. The canyon transport mechanisms were investigated, and the convective and turbulent mass-transport rates compared to clarify their role in aerosol transport. The horizontal distribution of aerosols showed acceptable evaluation metrics for both mass and number. Flow and pollutant concentrations were more complex than those in idealized street canyon networks. Vertical turbulent mass-transport rate was found to dominate the mass transport process compared with the convective transport rate, contributing more than 70% of the pollutant transport process. Our findings highlight the necessity of examining various aerosol metric due their distinct dispersion behaviour. This study introduces a comprehensive high-resolution modelling framework that accounts for dynamic meteorological and aerosol background boundary conditions, real-time traffic emission, and detailed building features, offering a robust toll for local urban air quality assessment.

Periodic approaching flows and pollutant dispersion of a single-sided generic building with natural ventilation

In real urban environments, wind velocities often exhibit significant time-dependent variations. However, the impact of these fluctuations on ventilation performance is not frequently addressed in the literature. To accurately predict the building ventilation performance, this paper intends to elucidate the influence of the unsteady approaching flow. Four distinct inflows, characterized by periodic sinusoidal fluctuations, are evaluated using large-eddy simulation (LES). A single-sided building model with natural ventilation is constructed and validated through a wind tunnel experiment. Four periodic inflows consist of combinations of two frequencies (f = 0.1 and 0.3 Hz) and two amplitudes (A = 0.06 and 0.09). This paper mainly compares the results of airflow patterns and ventilation performance with those of stable inflows. The results indicate that periodic inflows cause greater fluctuations in the velocity fields on the leeward side. At higher frequencies and lower amplitudes, the vertical distribution of indoor bottom vortices is relatively dispersed. It shows that periodic flows lead to noticeable changes in the ventilation rate, with a deviation between instantaneous and average Q* ranging from 13.8% to 16.5%. Compared to the stable inflow, the impacts of periodic inflows on ventilation performance vary over time; 6% and 9% variations in incoming velocities result in deviations of up to 17.5% in ventilation rates. The frequencies and amplitudes of the periodic inflows do not exhibit a linear relation with ventilation rate. Therefore, it is prudent to be cautious about adopting averaged incoming wind velocities in predicting ventilation performance. This study helps in the more accurate prediction of single-sided natural ventilation.

EMDet: An entropy blending and multi-link parallel feature enhancement detection model for gas pipeline weak leakage detection

To improve the detection accuracy of gas pipeline leakage detection (PLD) especially when the leakage is weak, we propose a hybrid deep learning model, named EMDet in this paper, which incorporates two proposed algorithms called entropy blending (EB) and multi-link parallel feature enhancement (MPFE). Firstly, the EB algorithm is used to determine the optimal number of decomposition layer Lo and the optimal intrinsic mode function Io for variational mode decomposition (VMD), elevating the leakage-related information in Io. Then, three coarse-grained scales have been applied to extract effective and robust features, where the coarse-grained scales are calculated based on the sizes required by the MPFE algorithm. Moreover, the MPFE algorithm is proposed to enhance the representation of features, thereby improving the detection accuracy of PLD. After that, the performance of the proposed EMDet has been evaluated on the negative pressure wave (NPW) data collected from realistic urban environments. Compared with the state-of-the-art PLD models, the performance of EMDet not only reaches the total accuracy of 98.67%, the F1-score of 98.65%, and the fault detection rate of 98.68%, but also reduces the false alarm rate to 0.66% and the missing alarm rate to 1.32%. Finally, the robustness results demonstrate the superior performance and broad application prospects of EMDet for PLD.

Hybrid learning strategies for multivariate time series forecasting of network quality metrics

This work addresses the challenge of forecasting temporal metrics that characterize cellular traffic behavior. The ultimate goal is to provide network operators with a valuable tool for modeling mobile network traffic and optimizing connected resources. The idea is to estimate beforehand the temporal evolution of some Quality-of-Experience (QoE) and Quality-of-Service (QoS) metrics, which is helpful for accurately tuning the allocation of network resources. Remarkably, these metrics (expressed as time series) are typically correlated, and changes in one time series can affect others in a variety of ways and to different extents. For example, high network delay (a QoS-related metric) is associated with degradation in voice quality over time (a QoE-related metric). Accordingly, we address the problem of cellular traffic forecasting with correlated time series, proposing three innovative hybrid learning strategies designed by combining the advantages of two approaches: (i) a statistical approach, implemented through the Vector Autoregressive (VAR) model, which encodes each metric as a combination of past values of the same metric along with a combination of values of other related metrics, resulting in a multivariate structure; and (ii) an approach based on deep learning techniques (specifically, CNN, LSTM, and GRU) which operate on such a multivariate structure to perform the forecasting. The resulting performance demonstrates the benefits of the proposed hybrid schemes (VAR-CNN, VAR-LSTM, VAR-GRU) over their pure counterparts, with a significant reduction in forecasting errors. The network metrics were gathered in a real urban cellular environment, where the presence of exogenous factors (e.g., interferences, weather conditions, etc.) makes the forecasting assessment particularly challenging.

A distributed route network planning method with congestion pricing for drone delivery services in cities

Unmanned aerial vehicle (UAV)-based commercial services, exemplified by drone delivery, have captured wide interest in tech companies, entrepreneurs, and policymakers. Structured route-based UAV operations have been implemented for traffic management of UAVs in support of commercial delivery services in cities. Yet, its essence, multi-path planning with constraints is not well solved in the existing literature. Centralized planning might result in inefficiencies and unfairness in the allocation of precious urban airspace to individual routes. This paper describes a novel distributed route planning method to support UAV operations in a high-density urban environment. The method allows each origin–destination (OD) pair to compete against other OD pairs for an optimized route (e.g. shortest distance), coordinated by a system-level evaluation, leading to a network design that maximizes the performance of not only the individual routes but also the entire system. The core concept is the introduction of congestion pricing, a soft constraint to coordinate the allocation of airspace. The method is tested in standard 2D scenarios and compared with other state-of-the-art methods. The results show that (1) the method is able to generate routes with short individual distances as well as occupying the least airspace by the route network; (2) in some complex scenarios, the method is able to find a solution in a short period of time while other state-of-the-art method fails. The method has also been applied to a real urban environment (Mong Kok in Hong Kong) to demonstrate its capability.

Cloud Based Data Centre for Managing Logistics in the Disaster

Considering the many man-made and natural disasters that have occurred in recent years, such as the September 2001 earthquake and the tsunami in Japan, the importance of problem solving processes cannot be ignored. The total damage caused by the disaster in Japan alone is estimated at more than $300 billion. Transportation and communications play an important role in disaster response and management to minimize loss of life, economic costs and impacts. Our research includes the development of emergency response systems for disasters of all sizes, focused on transportation systems designed to use and communicate information and technology. In this article, we discuss the use of technology for disaster management using smart transportation, including mobile, mobile and cloud. The system is intelligent because it can collect information from many places and locations, including the situation and make decisions regarding the use of the communication process, making the vehicle more efficient. Hybrid vehicle communications based on vehicle-to-vehicle and vehicle-to-infrastructure protocols are being exploited opportunistically. The effectiveness of our system has been demonstrated by simulating the impact of disasters on the real urban environment and comparing the situation with our existing disaster management systems. We declare that the adoption of our plan has led to the improvement and stabilization of traffic and evacuation.

Electric charging stations for electric vehicles in a traffic flow simulation model

This article substantiates the need to use simulation modeling in planning the location of parking lots equipped with charging stations for electric cars. Moscow is actively developing infrastructure for the use of electric cars for personal use, but there is a limited number of charging stations in the city districts. This increases the load on the transportation framework of the capital. Creating a simulation model of the transport system allows us to identify its “bottlenecks” related to the effective organization of road traffic and the creation of a sustainable environment. The use of methods of structural analysis, synthesis, groupings, information and simulation modeling allowed to establish all key objects of the problem area, their qualitative and quantitative characteristics necessary to create a simulation model. The created simulation model is based on the developed formal models of changes in the states of each class of objects, corresponding to the behavior in the real urban environment. To demonstrate the obtained results, a three-dimensional model corresponding to the simulation model is developed.

Городской вид как культурная ценность

The article analyzes cityscapes from the point of view of their value for the formation and preservation of the spatial and temporal unity of the cultural landscape of the historical city. The author distinguishes between cityscapes (urban views) as images of any urban location or composition and cityscapes (urban views) as configurations of architectural and other material spaces that we can observe in a real urban environment. The cityscape is defined in this article as a freely perceived, “readable” architectural urban composition, having high artistic significance and “supporting” the surrounding urban tissue, being the most important factor in the activity of citizens and guests of the city, and is also “responsible” for a specific identity urban space as a whole. A cityscape usually consists of several spatial patterns. The space of a traditional Russian city is formed as a system of urban views that reveal both its geographical design and its sacred semantics. Damage (destruction) of one or more cityscapes leads to degradation of the urban environment as a whole. The author defines the main reasons for the destruction of cityscapes and determines the consequences of these processes. The author concludes that cityscapes (urban views), as spatial structures that form the supporting frame of the visual environment, are fundamental part of the entire culture structure called ‘the city’. The system of urban views carries a number of integration functions: logistic, aesthetic, semiotic, local-historical, cultural-identification, social. The system of cityscapes directly reveals the specifics of the city. The preservation of cityscapes as fundamental pillars of the urban environment and as cultural heritage values ensures the actuality of the historical past, the spatialtemporal unity of an identical urban environment, and also instills in citizens a sense of belonging to their city, which exists only in a ‘long time’ of culture.

Визуальная репрезентация исторического города в цифровых медиа

The article analyses the visual representation of the historical city in digital media as one of the leading ways of urban identity forming. The author shows that the connection of the image with the city, which is a territorial carrier of visual and symbolic information, and with city digital representation is established and coordinated with the help of an intermediary – digital media, including social networks. On the example of Veliky Novgorod, it is investigated how the image of the city in the media environment shapes the idea of the real urban space for most Internet users. The article identifies the main elements of urban space that emphasize Veliky Novgorod’s status as a historical city: culturalhistorical and natural-landscape. The visual representation of the historic city emphasizes the uniqueness of a place and expresses local identity, which allows to distinguish a certain urban space in the endless flow of visual data. At the same time, the author notes that digital media do not display the entire urban space, but only the part that is recorded and then actively disseminated by Internet users. Such incompleteness of the visual representation of the historical city provokes the emergence of socio-cultural distortions: the reproduction of basic visual patterns works to form a stereotypical image that does not reflect the heterogeneity of the real urban environment.

Стресс-факторы городской цифровой среды: личностные детерминанты восприимчивости

Background. Modern digital urban environment, as a representation of real urban environment, functions according to the rules of living environment, including its being a real source of stress. The solution of practical tasks to improve the quality of life in the conditions of modern urban environment determine the relevance of research on stress factors of digital urban environment and the study of their possible determinants. Objectives. The study aims to assess the role of personal characteristics of young people, determining subjectively faster reaction to stress factors of digital urban environment. Study Participants. The study involved 619 participants aged from 17 to 25 years (41% males, 59% females), students of colleges and universities of Ekaterinburg. Methods. To study the subjective significance of stress factors of the digital environment, the authors created a specialised questionnaire, which involved the assessment of the 34 proposed stress factors on a scale from 0 to 4 points. The psychodiagnostic techniques HEXACO and “Dark Triad” were used to study personal characteristics of the respondents. Factor analysis, Cronbach's alpha, and linear regression analysis were used to process quantitative data. Results. As a result of factorization, 4 groups of stress factors in the digital urban environment as perceived by young people were identified: imperfection of urban digital services and applications; information coercion and security risks; aggressive behaviour and low culture of interaction of subjects in the Internet; aesthetic unattractiveness of urban digital space. Regression analysis made it possible to build statistically significant models for each of the four identified factors. It was found that the main predictors for sensitivity to stressors of the digital urban environment are negative personality traits. Conclusions. The materials of the conducted research indicate the importance of personality characteristics in determining stress reactions of young people to negative factors of digital urban space, but reflect the variability of their impact on stress: weakening the effect of some types of stressors, but at the same time enhancing the effect of other stressors.

Development of a networked photonic‐enabled staring radar testbed for urban surveillance

AbstractUrban surveillance of slow‐moving small targets such as drones and birds in low to medium airspace using radar presents significant challenges. Detecting, locating and identifying such low observable targets in strong clutter requires both innovation in radar hardware design and optimisation of processing algorithms. To this end, the University of Birmingham (UoB) has set‐up a testbed of two L‐band staring radars to support performance benchmarking using datasets of target and clutter from realistic urban environment. This testbed is also providing the vehicle to understand how novel radar architectures can enhance radar capabilities. Some of the challenges in installing the radar at the UoB campus are highligted. Detailed benchmarking results are provided from urban monostatic and bistatic field trials that form the basis for performance comparison against future hardware modification. The solution to the challenge of interfacing the radar to the external oscillators is described and stand‐alone bench tests with the candidate oscillators are reported. The testbed provides a valuable capability to undertake detailed analysis of performance of Quantum photonic‐enabled radar and allows for its comparison with conventional oscillator technology for surveillance of low observable targets in the presence of urban clutter.

MDP-based connectivity and availability models for Internet of Vehicles

Smart and connected vehicles have enabled a series of services and applications in intelligent transportation. Such vehicles introduce a new paradigm that supports the Internet of Vehicles, where content and resource sharing happens dynamically through Vehicle to Everything (V2X) communication. Communication technologies, such as vehicular and cellular networks, are expected to reliably support connections and mobile computing. However, due to challenges related to highly dynamic topologies in urban environments, the feasibility and reliability of vehicular communications in real urban environments have been discussed in recent works. In light of solving the issues that originated from unstable connectivity, we propose an MDP-based connectivity model which estimates link stability for data delivery. Moreover, from analyses, it was evident that the predictability of individual vehicle connectivity directly depends on the repeatability of its connection patterns. Consequently, we propose an availability model which identifies the suitability of connectivity status to determine the vehicles that provide high availability conditioned on their mobility.

Analysis of UAV path planning effectiveness and evaluation index scores combined with urban logistics scenarios

Using logistics drones for distribution is an optional solution to the problems of saturated logistics industry, insufficient transportation capacity, and high work pressure on employees in real cities. In a realistic urban environment, it is of practical significance to establish a logistics drone path planning model to improve the efficiency of logistics drones by fully considering the multiple requirements of both logistics service parties, such as time and location, and aiming at minimizing transportation costs. Aiming at this problem, this paper analyzes and studies the path planning problem of unmanned aerial vehicles based on the factors that need to be considered in actual life logistics distribution. Firstly, the actual scenario requirements of logistics UAV applications are analyzed and a path planning algorithm for this scenario is enumerated. Subsequently, mathematical models are established from both path planning and customer satisfaction to assess the performance of logistics drones. Then, a comparative analysis of four existing classical path planning algorithms is conducted, and simulated annealing algorithm is used to optimize logistics delivery scenarios for path planning. Finally, combining the mathematical model and simulated annealing algorithm constructed in the previous article, logistics UAV simulation experiments are conducted in urban distribution scenarios and an ideal path planning model is obtained. The work of this article provides a certain reference basis for logistics companies in the application of logistics UAVs and the selection of path planning methods.

Heat exposure variations and mitigation in a densely populated neighborhood during a hot day: Towards a people-oriented approach to urban climate management

Climate change and increasing urbanization call for the effective adaptation of cities to extreme heat. To improve the applicability of the research, sophisticated computational fluid dynamics models are being developed to capture the complexity of climate in a real urban environment, while a human-oriented paradigm is emerging concurrently. In this paper we present a synergy of these approaches by analyzing outdoor thermal exposure on five different pedestrian routes in Prague-Dejvice (Czech Republic), employing the PALM modeling system and realistic use-cases. Our simulations reveal important spatio-temporal variability in the Universal Thermal Climate Index (UTCI) in the urban neighborhood. Our findings particularly emphasize the negative effect of open spaces, such as gaps between buildings and shorter buildings, on the thermal exposure of pedestrians. These configurations allow more direct irradiation to reach ground level, while the other adverse climatic characteristics of midrise/highrise developments are largely preserved. The effect of urban greenery is quite variable during the day. Trees can reduce UTCI by up to 10 °C, but this strongly depends on the location (e.g., distance from neighboring buildings). Irrigated grass reduces UTCI by about 1.8 °C, but dried grass has little heat mitigation effect. In conclusion, our results suggest that expert-based knowledge together with sophisticated and fine-scale models can identify effective heat stress reduction measures without draconian changes to, or investments in, the urban environment.

Virtual environments in the nineteenth century: the spectacle of old London

ABSTRACT This article considers the appeal of immersive recreations of old London for nineteenth-century audiences. When discussed by scholars now, they are most often presented as conduits of official ideology engaged in promoting a triumphalist narrative of bourgeois ascendance. Here, I explore their appeal to popular audiences, arguing that they presented a more ambivalent set of meanings than is generally recognised and highlighting instances in which the beholders’ experience departed from the stated intentions of the makers or organisers. The article draws out the pervasiveness of the riverside motif, which I argue carried a subtext of yearning for a lost harmony between urban and natural environments in the modern metropolis. The immersive illusionism of these reconstructions has been associated with the idea of “passive” spectatorship in which the viewer is enthralled and their critical faculties dulled or immobilised. I argue against this that the immediacy of old London attractions allowed them to become part of the dream geography of modern spectators severed from their own past. As “mind’s eye” images, they functioned as phantasmagoric interstitial spaces that could be called upon to inform and transform the real urban environment, and in which emotions such as loss, trauma and desire could be worked out through the free play of the imagination.

How does particulate matter affect plant transcriptome and microbiome?

Phylloremediation for the reduction of air particulate matter (PM) is an interesting opportunity to significantly contribute to improve the air quality of urban environment. The aim of this study was to: 1) gain insight into the gene regulatory networks modulating leaf responses to polluted air, 2) identify possible changes in the leaf microbiome due to particulate matter in the real urban environment. The leaf transcriptome and microbiome were analyzed for Photinia x fraseri L. plants cultivated for three months in pots in two close-by areas under different levels of air PMs (low and high). PCA and heat map analysis showed that 28 differentially expressed genes in common between the three pairwise comparisons were able to clearly discriminate plants under higher PM levels. The pollutants were mainly sensed by plants through a restructuring modification of cell wall and membrane due to the main repression of lipid desaturases. In addition, high PMs showed a clear repression of genes belonging to primary metabolism pathways involved in C assimilation. Microbiome analysis showed no significant changes in taxonomic diversity indexes for the bacterial communities, whereas fungi belonging to the genera Epicoccum and Dioszegia were differently affected by the different exposure to PM levels. A model of transcriptional regulation to air PMs in plants has been proposed.