Urban Flow Research Articles

Probabilistic Water Demand Forecasting Using Quantile Regression Algorithms

AbstractMachine and statistical learning algorithms can be reliably automated and applied at scale. Therefore, they can constitute a considerable asset for designing practical forecasting systems, such as those related to urban water demand. Quantile regression algorithms are statistical and machine learning algorithms that can provide probabilistic forecasts in a straightforward way, and have not been applied so far for urban water demand forecasting. In this work, we fill this gap, thereby proposing a new family of probabilistic urban water demand forecasting algorithms. We further extensively compare seven algorithms from this family in practical one‐day ahead urban water demand forecasting settings. More precisely, we compare five individual quantile regression algorithms (i.e., the quantile regression, linear boosting, generalized random forest, gradient boosting machine and quantile regression neural network algorithms), their mean combiner and their median combiner. The comparison is conducted by exploiting a large urban water flow data set, as well as several types of hydrometeorological time series (which are considered as exogenous predictor variables in the forecasting setting). The results mostly favor the linear boosting algorithm, probably due to the presence of shifts (and perhaps trends) in the urban water flow time series. The forecasts of the mean and median combiners are also found to be skillful.

Identification of Samin Community Culture in Bojonegoro Towards Environmental Sustainability in Rural Area

Globally, currently more than 50 percent of the world's population lives in urban areas. It is projected that 70 percent of the world's population will live in cities by 2050. Given the sheer scale of urbanization and its environmental implications, it is important to consider the interrelationships between urban and rural contexts in an integrated manner. Achieving sustainable development requires priorities and the implementation of tailored policies in both urban and rural areas. One way that can be done is to strengthen rural cultural values in communities and indigenous peoples. In this study, the case study raised is the cultural value of the Samin Bojonegoro community in maintaining cultural values and preventing the flow of urbanization of its population. The creation of a livable environment through the cultural values of the Samin community will be raised through this research through ethnographic approach with synchronic and diachronic presentation. As a result The Samin community, which is rooted in the culture of an agrarian society, has not changed much in terms of vegetation, land use, and cultural activities. This has an impact on environmental sustainability and cultural establishment so that it seems as if it has a border from outside influences while also protecting cities from urbanization flows and environmental burdens

Impact of COVID-19 pneumonia on population mobility in ethnic minority areas

The main channel for the spread of COVID-19 is macro and micro population flow, and population and material flow are important means to promote economic development and ensure people’s living standards, especially for ethnic areas with relatively backward economic development. Based on Baidu migration data, this paper confirms that population flow data has a strong correlation with urban GDP indicators, and quantitatively analyzes the population inflow, population outflow and intra-city population flow in cities in ethnic areas during the new coronavirus epidemic. Influenced by the epidemic, after the Spring Festival in 2020, China’s urban population flow showed a trend of first sharp decline and then a slow upward trend, and the reduction of population outflow and population inflow after the epidemic reflects the limited long-distance population flow in my country, while the increase in urban population flow reflects the post-epidemic population flow. Short-distance mobility increased slightly. The impact of the new coronavirus pneumonia epidemic on different ethnic regions across the country varies greatly. The northwestern ethnic regions are greatly affected by the epidemic. The average population flow in some cities has dropped by more than 50%, while the impact on the southwestern ethnic regions is relatively small. Analyzing the population flow and economic changes in ethnic areas during the epidemic, and demonstrating the impact of the epidemic in each city will help to formulate more effective prevention and control strategies and poverty alleviation measures for these areas. The analysis results can provide decision-making reference for relevant departments.

Lanthanides Release and Partitioning in Municipal Wastewater Effluents.

The use of lanthanides is increasing in our society, whether in communication technologies, transportation, electronics or medical imaging. Some lanthanides enter urban wastewater and flow through municipal wastewater treatment plants (WWTPs). However, little is known about the effectiveness of treatment processes to remove these elements and the concentrations released in effluents to receiving waters. The main objective of this study was to investigate the fate of lanthanides in various wastewater treatment processes. A secondary objective was to better understand the fate of medical gadolinium (Gd) complexes; anthropogenic inputs were differentiated from geological sources using an approach based on concentration normalization with respect to chondrite Post-Archean Australian Shale (PAAS). The hypothesis was that most lanthanides, especially of geological origin, are associated with the particulate phase and could be efficiently removed by WWTPs. To monitor these elements in different WWTPs, various urban influents and effluents from simple aerated lagoons to advanced treatments were sampled in Canada. The results showed that the rates of lanthanide removal by treatment processes decrease with their atomic number; from 95% for cerium (Ce) to 70% for lutetium (Lu), except for Gd, which was minimally removed. The normalization approach permitted the determination of the origin of Gd in these wastewaters, i.e., medical application versus the geological background. By distinguishing the geogenic Gd fraction from the anthropogenic one, the removal efficiency was evaluated according to the origin of the Gd; nearly 90% for geogenic Gd and a rate varying from 15% to 50% in the case of anthropogenic Gd. The processes using alum as the flocculating agent had the highest removal efficiency from wastewater.

Evaluation Index System of Economic and Social Development Pilot Area Based on Spatial Network Structure Analysis.

In order to improve the evaluation effect of the economic and social development pioneer area, this paper constructs the evaluation index system of the economic and social development pioneer area based on the spatial network structure analysis method and obtains an intelligent analysis system. Moreover, from the perspective of economic development information flow, this paper uses information flow direction analysis method and advantage flow analysis method to discuss the structural characteristics of urban economic development network in the economic belt, providing new methods and perspectives for the study of urban economic development flow. In addition, this paper attempts to propose a universal method for quantitative research on the “flow space” structure of urban economic development as the forward-looking content of urban economic development. According to the simulation test results, it can be seen that the evaluation index system of the economic and social development pilot area based on the analysis of the spatial network structure proposed in this paper has a good effect.

Understanding urban fluid flows urgent for dispersing pollution

Arch vortices, which form between buildings in cities, create concentrated areas of poor air quality

On the generation and destruction mechanisms of arch vortices in urban fluid flows

This study uses higher-order dynamic mode decomposition to analyze a high-fidelity database of the turbulent flow in an urban environment consisting of two buildings separated by a certain distance. We recognize the characteristics of the well-known arch vortex forming on the leeward side of the first building and document this vortex's generation and destruction mechanisms based on the resulting temporal modes. We show that the arch vortex plays a prominent role in the dispersion of pollutants in urban environments, where its generation leads to an increase in their concentration; therefore, the reported mechanisms are of extreme importance for urban sustainability.

Measuring urban water circularity: Development and implementation of a Water Circularity Indicator

Urban Water Management (UWM) involves balancing the inflows and outflows of water such that water entering and leaving the system boundary reduces with time. Several frameworks and indicators have been formulated for UWM with a limited focus to achieve circularity of water flows at all the phases of the engineered urban water cycle. A novel indicator called ‘Water Circularity Indicator’ (WCI) is developed in this study to assess, monitor and improve the circularity of urban water flows. The WCI is derived from Material Circularity Indicator developed by Ellen McArthur Foundation and Granta design. In the current study, WCI is initially validated using 100 scenarios considering the variation of 5Rs, i.e., reduce, reuse, recycle, reclaim and restore. Further, WCI is compared with other indicators focusing on urban water management from the literature. The evaluation of results indicate that WCI correlates with most of the indicators selected for comparison. The WCI uses the water mass balance principle in its derivation and distinctively captures reuse, recycling, reclamation and restoration strategies in a single indicator value compared to other indicators. The WCI provides maximum information in a single indicator value ranging from 0 to 1.0. A higher value of WCI indicates lesser extraction of virgin water resources and wastewater disposal with maximum water circulation within the city under consideration. The novelty of WCI lies in its unique approach of considering all 5Rs and easy interpretation for decision-makers across multiple domains. WCI is recommended to be used by city authorities and policy makers for achieving water goals and for Circular Economy (CE) implementation. Policies can be formulated based on WCI to enhance CE in the water sector and reduce virgin water consumption, ultimately leading to water conservation.

Decision support for sustainable urban mobility: A case study of the Rhine-Ruhr area

• A framework for integrated innovation policy of sustainable urban mobility is set. • A multi-actor and multi-level approach is considered. • Transformation process is step-wise guided. • An interactive scenario-simulation tool for the decision makers is developed. • Mobility demand and supply must be balanced to transform sustainable urban future. Sustainable urban governance considers the simultaneous reduction of traffic-related pollution, social equity for mobility access, healthy market competition among the service providers, and convenient use of multi-modal transportation enabled by digital technologies. However, the rise of more complex urban systems challenges decision-making processes to design and implement environmentally sustainable, economically viable, and socially acceptable urban mobility systems. The paper sets an innovative and collaborative decision-making framework for integrated sustainable urban policy design. Firstly, schematic integration of urban flows from disintegrated operation systems toward fully integrated, inclusive, and sustainable urban systems is conceptualized. Based on this concept a multi-level decision-making process within urban mobility policies is designed relying on a Multi-Criteria Decision Aid (MCDA) for resource allocation decisions at the micro, meso, and macro levels. Thereby, a range of urban futures is adequately addressed, be it smart, sustainable city concepts, peri-urbanization, and business as usual scenarios. The integrated model for a pilot case of the metropolitan region of Rhine-Ruhr is tested in this paper. If Sustainable City scenario is the desired one, push and pull measures should be equally weighted. Based on MCDA sensitivity analysis, policy recommendations and a practical hands-on tool for urban planning are derived.

Challenges in Quantifying Losses in a Partly Urbanised Catchment: A South Australian Case Study

Quantifying hydrological losses in a catchment is crucial for developing an effective flood forecasting system and estimating design floods. This can be a complicated and challenging task when the catchment is urbanised as the interaction of pervious and impervious (both directly connected and indirectly connected) areas makes responses to rainfall hard to predict. This paper presents the challenges faced in estimating initial losses (IL) and proportional losses (PL) of the partly urbanised Brownhill Creek catchment in South Australia. The loss components were calculated for 57 runoff generating rainfall events using the non-parametric IL-PL method and parametric method based on two runoff routing models, Runoff Routing Burroughs (RORB) and Rainfall-Runoff Routing (RRR). The analysis showed that the RORB model provided the most representative median IL and PL for the rural portion of the study area as 9 mm and 0.81, respectively. However, none of the methods can provide a reliable loss value for the urban portion because there is no runoff contribution from unconnected areas for each event. However, the estimated non-parametric IL of 1.37 mm can be considered as IL of EIA of the urban portion. Several challenges were identified in the loss estimation process, mainly when selecting appropriate storm events, collecting data with the available temporal resolution, extracting baseflow, and determining the main-stream transmission losses, which reduced the urban flow by 5.7%. The effect of hydrograph shape in non-parametric loss estimation and how combined runoff from the effective impervious area and unconnected (combined indirectly connected impervious and pervious) areas affects the loss estimation process using the RORB and RRR models are further discussed. We also demonstrate the importance of identifying the catchment specific conditions appropriately when quantifying baseflow and runoff of selected events for loss estimation.

A Tourist Behavior Analysis Framework Guided by Geo-Information Tupu Theory and Its Application in Dengfeng City, China

With the development of tourism and the change in urban functions, the analysis of the spatial pattern of urban tourist flows has become increasingly important. Existing studies have explored and analyzed tourist behavior well, using the appropriate digital footprint data and research methods. However, most studies have ignored internal mechanisms analysis and tourism decision making. This paper proposed a novel framework for tourist behavior analysis inspired by geo-information Tupu, including three modules of the spatiotemporal database, symptom, diagnosis, and implementation. The spatiotemporal database module is mainly used for data acquisition and data cleaning of the digital footprint of tourists. The symptom module is mainly used for revealing the spatial patterns and network structures of tourist flows. The diagnosis and implementation module is mainly used for internal mechanism analysis and tourism decision making under different tourist flow patterns. This paper applied the proposed research framework to Dengfeng City, China, using online travel diaries as the source of digital footprint data, to analyze its tourist behavior. The results were as follows: tourist flows of Dengfeng were unevenly distributed, thus forming an obvious core–periphery structure with intense internal competition and unbalanced power. The difference in tourism resources between its northern and southern areas remains a challenge for future tourism development in Dengfeng.

Accessibility and Economic Connections between Cities of the New Western Land–Sea Corridor in China—Enlightenments to the Passageway Strategy of Gansu Province

In 2019, China proposed the New Western Land–Sea Corridor (NWLSC) to strengthen economic and trade cooperation between China and Southeast Asia. As an important province in western China, Gansu plays a crucial role in transportation and cultural exchange in the Silk Road Economic Belt (SREB). Thus, how to develop the strategic passageway of Gansu Province becomes the research focus. In order to enhance the radiation effect of the NWLSC on the northwestern region and help Gansu Province expand its pattern of expanding, this paper firstly selects 16 core cities in this Corridor by using an accessibility method and an urban flow intensity method; then, analyzing the status of accessibility and the economic connection patterns between those cities; and lastly, obtaining conclusions that the accessibility of space layout is “corridor style”, the spatial distribution of urban flow intensity is balanced, and Gansu should actively participate in southbound gateway and gain the full advantages of the “golden passageway”. To sum up, this paper is innovative in terms of regional selection, research methods, and theoretical significance.

Intelligent Decision Support System for Modeling Transport and Passenger Flows in Human-Centric Urban Transport Systems

Engineering human-centric urban transport systems should be carried out using information technology in forecasting traffic and passenger flows. One of the most important objects of urban transport systems’ progress is modeling patterns of transport flows and their distribution on the road network. These patterns are determined by the subjective choice of city residents of traffic routes using public and private transport. This study aimed to form a sequence of stages of modeling transport and passenger flows in human-centric urban transport systems and passenger flows in the human-centric urban intelligent transport systems and to determine the patterns of change to the gravity function of employees of municipal services. It was revealed that the trip distribution function of workers of urban service enterprises can be described by the attributes of the structure of the city, socio-economic data, and attributes characterizing the zones and its residents.

Pick-Up and Delivery Problem for Sequentially Consolidated Urban Transportation with Mixed and Multi-Pupropse Vehicle Fleet

Different urban transportation flows (e.g., passenger journeys, freight distribution, and waste management) are conventionally separately handled by corresponding single-purpose vehicles (SVs). The multi-purpose vehicle (MV) is a novel vehicle concept that can enable the sequential sharing of different transportation flows by changing the so-called modules, thus theoretically improving the efficiency of urban transportation through the utilization of higher vehicles. In this study, a variant of the pick-up and delivery problem with time windows is established to describe the sequential sharing problem considering both MVs and SVs with features of multiple depots, partial recharging strategies, and fleet sizing. MVs can change their load modules to carry all item types that can also be carried by SVs. To solve the routing problem, an adaptive large neighborhood search (ALNS) algorithm is developed with new problem-specific heuristics. The proposed ALNS is tested on 15 small-size cases and evaluated using a commercial MIP solver. Results show that the proposed algorithm is time-efficient and able to generate robust and high-quality solutions. We investigate the performance of the ALNS algorithm by analyzing convergence and selection probabilities of the heuristic solution that destroy and repair operators. On 15 large-size instances, we compare results for pure SV, pure MV, and mixed fleets, showing that the introduction of MVs can allow smaller fleet sizes while approximately keeping the same total travel distance as for pure SVs.

Impact of urban structure on infectious disease spreading

The ongoing SARS-CoV-2 pandemic has been holding the world hostage for several years now. Mobility is key to viral spreading and its restriction is the main non-pharmaceutical interventions to fight the virus expansion. Previous works have shown a connection between the structural organization of cities and the movement patterns of their residents. This puts urban centers in the focus of epidemic surveillance and interventions. Here we show that the organization of urban flows has a tremendous impact on disease spreading and on the amenability of different mitigation strategies. By studying anonymous and aggregated intra-urban flows in a variety of cities in the United States and other countries, and a combination of empirical analysis and analytical methods, we demonstrate that the response of cities to epidemic spreading can be roughly classified in two major types according to the overall organization of those flows. Hierarchical cities, where flows are concentrated primarily between mobility hotspots, are particularly vulnerable to the rapid spread of epidemics. Nevertheless, mobility restrictions in such types of cities are very effective in mitigating the spread of a virus. Conversely, in sprawled cities which present many centers of activity, the spread of an epidemic is much slower, but the response to mobility restrictions is much weaker and less effective. Investing resources on early monitoring and prompt ad-hoc interventions in more vulnerable cities may prove helpful in containing and reducing the impact of future pandemics.

Model construction of urban agglomeration expansion simulation considering urban flow and hierarchical characteristics

Model construction of urban agglomeration expansion simulation considering urban flow and hierarchical characteristics

Building a BUS: Technoscience and the emerging mode of organising interventions in Indian Cities

Despite the growing economic footprint of cities, surprisingly little attention has been devoted to understanding the relation between technoscience and cities. The field of urban technoscience seeks to develop a body of knowledge to plan and design vital urban metabolic flows including water, waste, sanitation, movement, and energy. Underlying this field is the urgency to intervene in cities to solve urban problems in a scientific fashion through the development of infrastructure plans and designs. As vital sites for India’s current political economy, cities are now witness to systematic attempts to alter the technoscientific base of cities in the country. How is this shift happening in India? Drawing upon research in Science and Technology Studies (STS), history of urban planning, and allied social science fields, this paper characterizes the shift as BUS – Big Urban Science and Engineering. The paper provides an analysis of BUS and concludes with some implications of BUS for urban change in India.

Freight Demand Distribution in a Suburban Area: Calibration of an Acquisition Model with Floating Car Data

The paper deals with the interaction between freight flows, land use, and economy of a suburban area. In urban freight distribution, the process of freight acquisition of commercial establishments represents a crucial element. Therefore, it is necessary to plan city logistics in order to reduce the negative externalities generated by freight transport without depressing the economic and social vitality. In order to estimate and evaluate the performance and impacts generated by urban freight distribution, Transport System Models (TSMs) play an important role in reproducing and forecasting the process of distribution of final products to retailers and consumers. In recent years, Information and Communication Technologies (ICTs) have made new sources of data in great amounts available at lower costs than data provided from traditional surveys. Among the different data sources, Floating Car Data (FCD), obtained through GPS trackers installed on board the vehicles, offer partial insights into the examined process with lower cost and provide continuous information in space and time. In order to obtain reliable results, it is necessary to combine TSMs and ICTs as observed data could feed Transport System Models and could allow their calibration and therefore their application in real cases. In the above context, the paper deals with TSMs related to estimating urban freight demand flows. The work carried out concerns the specification-calibration-validation of a freight zonal acquisition model by means of FCD related to interzonal trips of commercial vehicles inside the Locride area (Reggio Calabria, Italy). The obtained models, estimated from FCD, could support the a priori evaluation of city logistics measures. The results are more important considering that they are obtained in an area with a lack of transport monitoring technologies. They could be adopted in other similar areas and confirm that adequate planning of city logistics determines advantages for environmental, social, and economic sustainability.

Modelling cascade dynamics of passenger flow congestion in urban rail transit network induced by train delay

A research into congestion propagation mechanism of urban rail transit passenger flow in train delay scenario is of great significance to the formulation of coordinated limitation measures of passenger flow among the operation lines in urban rail transit networks. This paper presents a methodology for modelling cascade dynamics of passenger flow congestion. In this method, firstly, a computing method of network passenger flow states based on load entropy is proposed to describe the overall load conditions of passenger flow in the network. Secondly, a rail transit network is developed and the computation formulas of load and capacity of nodes have been established combining with a comprehensive consideration of nodes’ topological passenger flow attributes. Thirdly, Trip Betweenness Centrality of nodes is proposed and calculated. Considering the function of rail transit line capacity and load distribution strategy, the passenger flow congestion in train delay scenario is established to calculate cascade dynamics of congestion and the state transition of urban rail transit network. A real case study on Beijing Metro Line 10 is used to demonstrate the proposed methodology. The results show that the load values of nodes and the distances from the initial failure nodes can be determined for the spreading scope of passenger flow congestion in disrupted metro line and adjacent metro lines.

Quantitative physical model of vulnerability of buildings to urban flow slides in construction solid waste landfills: a case study of the 2015 Shenzhen flow slide

Quantitative physical model of vulnerability of buildings to urban flow slides in construction solid waste landfills: a case study of the 2015 Shenzhen flow slide