Design Of Urban Systems Research Articles

Commuting behaviors response to living and working built environment: Dissecting interaction effects from varied supply and demand masses

Most developed megacities have experienced poly-centralization and suburbanization, leading to job-housing mismatches and negative outcomes such as increased commuting distances and frequencies. Recognizing the scarcity of structural analysis concerning the attractiveness of commuting's geographic endpoints, this study examines the diverse impact of the built environment at living and working locations on commuting flows, considering various supply-demand masses and distance levels. Utilizing a Gradient Boosting Decision Tree (GBDT) model, the study highlights the importance of job-housing ratio, POI diversity, and subway station proximity in employment locations, while informal area rates and subway proximity remain significant in residential locations. A three-dimensional analysis further indicates that achieving a perfect job-housing balance in megacities remains a dream, with each area presenting unique challenges requiring tailored solutions beyond a one-size-fits-all approach. Potential policies, such as planning large residential areas in the inner suburbs and upgrading convenient infrastructure in the outer suburbs, are proposed. Furthermore, with the uncovered distinct interaction effects of built environment on commuting behavior across various masses and distances, common perceptions related to mixed-use land and the role of informal settlement, are critically challenged. This extends our understanding of sustainable urban system design and provides references for planning policies.

Agroecology for the City—Spatialising ES-Based Design in Peri-Urban Contexts

The design of urban systems that allow growth while also maximising ecosystem services is identified as an important priority for creating a Good Anthropocene. An ecosystem service (ES)-based approach to landscape interventions maximises the provision of ESs, and in doing so, repairs and reinforces threatened ecological planetary boundaries. As an urbanising planet, cities are critical frontiers of human interaction with these planetary boundaries, and therefore a critical arena for ES-based intervention. Globally, the predominant pattern of urbanisation is dedensification, an outwardly expanding trend where cities are growing in physical extent at a higher rate than their population growth. We therefore require spatially explicit tools capable of reconciling dedensification and Good Anthropocene visions. We propose a methodology that integrates agroecology and urbanisation and is focussed specifically on the supply of targeted regulating ESs. This ‘Agroecology for the City’ differs from conventional urban agriculture discourse and its preoccupation with food security. Our research interest is agroecological farm systems’ (AFSs) capacity to provide critical life support services in a spatially effective manner to urban systems. Our recent research introduced a new GIS-based model (ESMAX) and a spatial agroecology approach that identified AFS configurations at a 1 ha scale which maximised the supply of three regulating ESs, as well as multifunctional performance across all three ESs combined. In the present research, we apply this process at a larger scale, with 1 ha and 4 ha AFS parcels being integrated with a real-world 200 ha peri-urban residential development. The AFS parcels and built-up areas are configured differently to maximise the supply of ESs identified as critical by the local community. We found that arrangements with AFS parcels interspersed evenly with built-up areas provided the best multifunctionality across the four ESs tested. This supports pathways for a Good Anthropocene that work with the global urbanising reality of dedensification and underpin the need for a hybrid science of rural/urban systems.

Guest Editorial: Special Issue on “Sustainable urban energy systems – Governance and citizen involvement”

Cities are responsible for over 75% of the total amount of global greenhouse gas emissions. They are also home to the majority of the Earth's population. Ambitious climate mitigation goals can only be realized by transforming fossil based urban energy systems into sustainable, low-carbon ones. This is a multidisciplinary challenge that goes way beyond the technological dimension. In the Special Issue to which this Guest Editorial contributes, a multi-disciplinary perspective is used, exploring governance, institutional, ethical and other aspects, pertaining to citizen involvement in sustainable urban energy systems. The main research questions are, “How can we address key challenges to the analysis and design of sustainable urban energy systems, as regards their governance and institutions, values, social acceptance, and citizen involvement?”, and “How can this contribute to shaping a multi-disciplinary academic research agenda?” Based on the main findings from the ten contributions to the Special Issue key challenges to sustainable urban energy system design, planning, and implementation are presented, including suggestions for future research.

ROSMOSE: A web-based decision support tool for the design and optimization of industrial and urban energy systems

Energy efficiency is crucial for the sustainable operation of industrial and urban sectors. However, practicing engineers seldom have access to open-source tools that can readily evaluate and compare scenarios. In this work, a novel web-based tool called ROSMOSE is developed and proposed for analyzing the energy efficiency of industrial and urban systems and comparing potential process integration options. This optimization framework computes and graphically represents the minimum energy requirements, the pinch temperatures, and the Grand and integrated Carnot composite curves of process systems. Results are used to design utility systems that meet energy demands, while minimizing a specified objective function, such as total cost or environmental impacts. The Quarto environment, in which ROSMOSE is built upon, allows the integration of various open-source software and tools, such as database handling software, process modeling suites, and optimization solvers, along with interactive data visualization and reporting tools. This paper discusses the application of ROSMOSE for the energy integration and total site optimization of a dairy process consisting of milk treatment, and cream and cheese production to demonstrate the tool features. Other integration options, such as the use of heat pumps or solar panels, and the production of soft drinks or biogas as value-added byproducts, are also proposed and evaluated. As a result, from 75 % to 90 % in fuel savings and up to 80 % CO2 emissions reduction in the dairy plant are identified by optimizing the utility systems integration. Moreover, complete electrification via heat pumps eliminates any fossil fuel needs and it results in 85 % energy savings and up to 96 % CO2 emissions reduction. The activation of renewable electricity sources, such as solar power, made plausible this fully electrified scenario. Finally, optimized waste management strategies led to in-house fuel production and net export of biogas to the grid, but they also reduce cheese yield by prioritizing the biogas production from whey upgrading process. In this way, decision-makers have access to a clear performance comparison for a list of system configurations to draw informed trade-offs. A similar approach could be adopted to aid decision-making for the design and operation of other industrial and urban energy systems using ROSMOSE.

Integrated urban land cover analysis using deep learning and post‐classification correction

AbstractThe quantification of urban impervious area has important implications for the design and management of urban water and environmental infrastructure systems. This study proposes a deep learning model to classify 15‐cm aerial imagery of urban landscapes, coupled with a vector‐oriented post‐classification processing algorithm for automatically retrieving canopy‐covered impervious surfaces. In a case study in Corpus Christi, TX, deep learning classification covered an area of approximately 312 km2 (or 14.86 billion 0.15‐m pixels), and the post‐classification effort led to the retrieval of over 4 km2 (or 0.18 billion pixels) of additional impervious area. The results also suggest the underestimation of urban impervious area by existing methods that cannot consider the canopy‐covered impervious surfaces. By improving the identification and quantification of various impervious surfaces at the city scale, this study could directly benefit a variety of environmental and infrastructure management practices and enhance the reliability and accuracy of processed‐based models for urban hydrology and water infrastructure.

Life cycle assessment of urban road networks: Quantifying carbon footprints and forecasting future material stocks

This study introduces a comprehensive framework designed to assess the carbon footprint of urban road networks, covering all stages from production to maintenance. Complementing this framework, a dedicated prediction model is also developed. Utilizing a machine learning methodology, specifically the Gradient Boosting Decision Tree (GBDT) algorithm, this model aims to accurately predict the material stock of urban road networks, thereby enhancing the overall understanding of their environmental impact. A case study focusing on Nanjing's infrastructure revealed that material production constitutes 78 % of the total emissions. Additionally, it was observed that the growth in the carbon footprint of Nanjing's urban road network has slowed down in recent years. The machine learning-based model, analyzing data from 2014 to 2020, accurately predicted the total material stock for 2021 and the stocks of different road construction materials, with a relative error under 2 %. This approach aids in the design of carbon-neutral urban transport systems and represents a stride in combating climate change.

Domestic sewage dispersion scenarios as a subsidy to the design of urban sewage systems in the Lower Amazon River, Amapá, Brazil

The final in natura discharge of urban domestic sewage in rivers in the Amazon is a widespread practice. In addition, there is an evident lack of knowledge about the self-depurative characteristics of the receiving water bodies in these rivers. This problem is a challenge for designing sanitary sewage system (SSS) projects in the region. We aimed to numerically simulate hydrodynamic scenarios to study pollutant dispersion processes in an urban stretch impacted by domestic sewage in the Lower Amazon River (Amapá, Brazil) using a hydrodynamic model calibrated and coupled to a dispersive model (Lagrangian) (SisBaHiA). The following methodological steps were performed: (a) bathymetric and liquid discharge experimental campaigns using acoustic techniques (acoustic doppler current profiler—ADCP); (b) identification of point and diffuse sources of pollution in the Santana Channel (CSA) and North Channel of the Amazon River (NCM) in Macapá; (c) calibration of the hydrodynamic model and simulation of the dispersive process of domestic sewage plumes; (d) simulation of dispersive process scenarios in two seasonal hydrological periods and different tidal phases. The results of the simulations indicated significant spatiotemporal variations in the plumes, suggesting critical restriction of water quality in the dry period. The hotspot water collection supply station for ETA-CAESA was found to be the most threatened site by diffuse and point source loads. The simulated impacts showed that concentration variation worsens seasonally, restricting the multiple uses of water in both seasonal periods, regardless of tide phase. The pollutant plumes near the coastal-urban zone were apparently more inhibited by the influence of currents, and, due to the greater dilution capacity in the center of the channel, by the effect reversing with the approximation to the riverbank. The research hypotheses were supported: (a) the process of self-depuration of pollutants in the NCM has considerable limitations in shallow areas, and (b) SSS design projects in the region of the Amazon estuarine complex require hydrodynamic and strict water quality assessment, especially when their hydrological-seasonal and bathymetric characteristics are significantly unfavorable to dispersive processes. Thus, a hydrodynamic analysis should be the primary criterion in designing any SSS projects in this stretch of the estuarine Amazon region.

Potential-risk and no-regret options for urban energy system design — A sensitivity analysis

This study identifies supply options for sustainable urban energy systems, which are robust to external system changes. A multi-criteria optimization model is used to minimize greenhouse gas (GHG) emissions and financial costs of a reference system. Sensitivity analyses examine the impact of changing boundary conditions related to GHG emissions, energy prices, energy demands, and population density. Options that align with both financial and emission reduction and are robust to system changes are called “no-regret” options. Options sensitive to system changes are labeled as “potential-risk” options.There is a conflict between minimizing GHG emissions and financial costs. In the reference case, the emission-optimized scenario enables a reduction of GHG emissions (−93%), but involves higher costs (+160%) compared to the financially-optimized scenario.No-regret options include photovoltaic systems, decentralized heat pumps, thermal storages, electricity exchange between sub-systems and with higher-level systems, and reducing energy demands through building insulation, behavioral changes, or the decrease of living space per inhabitant. Potential-risk options include solar thermal systems, natural gas technologies, high-capacity battery storages, and hydrogen for building energy supply.When energy prices rise, financially-optimized systems approach the least-emission system design. The maximum profitability of natural gas technologies was already reached before the 2022 European energy crisis.

Utilising participatory approaches to enhance social acceptance in the design of urban recycling systems

Utilising participatory approaches to enhance social acceptance in the design of urban recycling systems

Development of Composite Pedestrian Level of Service Model in Urban Milieu at Midblock Sections

The pedestrian mode is gaining recognition as a basic building block in urban system design. Increasing attention is being given to developing vehicle-free zones to reduce urban pollution and return the inner city to its former role as a place for personal interaction. Attempts are being made to improve the walking experience, to make it more safe, convenient, and attractive especially in urban milieu to promote sustainable development. To provide the best pedestrian environment, it is necessary to understand pedestrian level of service. Conventional techniques of LOS determination consider the basic mobility characteristics of the pedestrian. The objective of this study is to develop a more accurate method of estimating level of service of pedestrians by developing composite indicators that integrate both qualitative and quantitative factors affecting both pedestrian and roadway conditions in the pedestrian movement. The relative importance of these multifaceted factors is assessed using Saaty scale and an Analytic Hierarchy Process is applied to determine the level of service. Field investigations include road network characterization and inventory studies, vehicular / pedestrian traffic characterization studies, pedestrian opinion surveys, expert opinion surveys. The approach has been applied to a major arterial road in Hyderabad city, Telangana, India in Mehdipatnam zone where pedestrian interactions are relatively high due to the commercial activity along the corridors. The stretches considered in the study exhibited Level of service "B" and "C" which implied necessary improvements to promote a good level of service.

Discharge coefficients formulae of grate inlets of complicated conditions for urban floods simulation and urban drainage systems design

With the acceleration of climate change and urbanization, all over the world is widely facing serious urban flooding problems. Grate inlets are key elements for the discharge exchange of surface flows and underground sewer flows in urban floods, so the accurate calculation of the overflow discharges of the grate inlets is related to the accurate simulation of the urban flood evolution process, which also plays an important role in the design of sustainable urban drainage systems. This study investigated the discharge coefficients of six types of grate inlets under different approaching discharges, transverse and longitudinal road slopes through 285 indoor 1:1 tests, mainly focusing on the supercritical flow conditions with less attention before. The experimental results show that: (1) With all other parameters being equal, as the interception discharge Q increases, the discharge coefficient increases. When the approaching Froude number increases, the discharge coefficient also decreases. The performance of parallel grate inlets in terms of discharge coefficients is not significantly different from that of vertical grate inlets. (2) Using Buckingham’s theorem of dimensional analysis, 12 groups of accurate grate inlets discharge coefficient calculation formulae were creatively proposed. The average relative errors of the 12 groups of formulae are 0.37% ∼ 5.41%, indicating that the calculated values of the formulae and the measured values are in good agreement. (3) The discharge coefficients of grate inlets were found to show a strong dependence on the Froude number of the approaching discharge, being in agreement with previous study result. But the relative error of individual data in this method is large, so the use of equations with more influencing parameters is recommended. A novel and effective method was also proposed to calculate the interception discharge of the grate inlets by iteration. This study can provide important references for the design and selection of grate inlets for urban drainage systems and also provide support for accurate simulation of urban floods.

A Petri Nets-Based Simulation Methodology for Modular Modeling and Performance Evaluation of Car-Sharing Networks

In the field of urban and green mobility, electric car-sharing networks have recently emerged as one of the promising alternatives, dealing with both environmental and transportation issues. Despite the increasing success of the shared mobility concept over the world, the design and management of such urban mobility systems implies strategic, tactical and operational challenges. To support designers and operators, all these issues constitute an emerging and challenging research topic, aiming to develop techniques and tools for modeling, analysis and optimization of such complex systems. In this contribution, based on the modeling and analysis power of stochastic timed Petri nets, a discrete event simulation approach is developed, taking into account their dynamic behavior complexities due to their self-service mode and characteristics including capacities of the stations, energy availability, rebalancing and maintenance activities. A real-life application is presented, to demonstrate the applicability and the potential of the proposed modeling and simulation analysis approach. <i>Note to Practitioners</i>&#x2014;To support designers, providers and managers of shared mobility programs, performance and optimization models and decision-making tools are needed. In this contribution, we deals with a powerful and modular stochastic timed Petri net methodology suitable for performance modeling and simulation analysis of such complex dynamical systems. The authors believe that this discrete event dynamic approach has significant promise for the future and to influence economic viability and operational efficiency of such emerging urban transportation systems.

Promoting the design of future urban metro systems to improve air pollution: Based on metal element pollution in Chinese metro system

Metro system metal element pollution and its human hazards have gained widespread attention. Using the Chinese metro as representative of a modern urban metro system, we investigated pollution levels, sources, and their health effects, to provide a basis for designing future healthy, sustainable urban metro environments. Through searching and analyzing previous studies on metal elements in the Chinese metro system, we showed that tunnels are the most contaminated areas for metal elements due to mechanical wear, while platforms, carriages, and halls are mainly affected by airflow diffusion. Using the UNEP-SETAC toxicity (USEtox) model to calculate health impacts, we determined that metal elements caused approximately 700 deaths per 1 million people annually. According to the US Environmental Protection Agency (US EPA) health risk model, health risks were evaluated from respiratory exposure for child and adult passengers, drivers, station attendants, and security checkers. Total incremental lifetime cancer risk (TILCR) for all populations was higher than 10−4, indicating a high carcinogenic risk. Finally, based on international studies, we propose corresponding strategies to improve metro system sustainability.

Multi-stage creep behavior of frozen granular soils: experimental evidence and constitutive modeling

The significance of ground freezing is becoming ever more germane as the design of new urban tunneling systems requires more complex geometries and higher bearing capacities, which are limited with conventional construction methods. Ground freezing is an advanced construction technique to make the water-saturated subsoil impermeable and temporarily increase its strength and stiffness. This study reports experimental investigations consisting of single-stage and multi-stage creep tests under uniaxial loading. The comparison of the different loading types reveals the influence of the stress–strain history on the rate- and temperature-dependent behavior of frozen granular soils. We extend the constitutive model for frozen soils proposed by Cudmani et al. (2022, Géotechnique, doi:10.1680/jgeot.21.00012) to consider stepwise loading and creep by coupling creep time with stress–strain history. Moreover, we simulate element tests and compare the simulations with our own experimental data as well as data from the literature to achieve the first step in validating the extended model. The good agreement of the numerical and experimental results confirms the constitutive model’s ability to capture the main features of the complex mechanical behavior of frozen granular soils for single-stage as well as multi-stage loading under constant temperatures.

Can transportation network companies improve urban air quality?

The environmental impacts of transportation network companies (TNCs) have been under intense debate with conflicting claims. However, there are limited empirical studies that quantify TNCs’ environmental impacts. This study examines the impact of TNCs on urban air quality in 388 metropolitan statistical areas (MSAs) in the U.S. over the period from 2010 to 2018. Based on difference-in-differences and yearly regression models, we generate three major findings: (1) The entry of TNCs has a positive impact on the overall urban air quality measured by AQI; (2) despite the positive impact on the overall air quality, TNC entry increases CO and NO2 pollution; and (3) TNC entry reduces PM10 pollution but has no statistically significant impact on PM2.5 pollution, and the effect on PM10 reduction takes 2 years to appear. The findings provide useful insights into the management and design of shared mobility and urban transport systems.

Application of Analytical Probabilistic Models in Urban Runoff Control Systems’ Planning and Design: A Review

Urban stormwater is known to cause a myriad of problems, ranging from flooding to water quality degradations. This paper provides an extensive review of analytical probabilistic model (APMs) used in the design of urban runoff control systems. APMs are closed-form mathematical expressions representing a long-term system’s output performance derived from the probability distribution of the system’s input variables. Once derived, the APMs are easy to handle, allow for sensitive analysis, and can be co-opted into optimization frameworks. The implementation of APM in the planning and design of runoff control systems will not only help address the runoff quantity and quality problems of urban stormwater, but will also go a long way in optimizing the benefits derived from the systems. This paper reviews studies that document the negative impacts of urbanization on runoff quantity and quality, and the best management practices (BMPs) used to mitigate the impacts. Three design methodologies used in urban stormwater control systems were reviewed. A detailed review of research on the development and use of APMs in urban stormwater management in various runoff control systems is presented, and recommendations are proffered.

THE OPERATIONAL CHARACTERISTICS AND THE UNWRITTEN DESIGN MANNERS OF THE DESIGN MANAGEMENT SYSTEM WITHOUT GUIDELINE BY FIXED MEMBERS

I clarify the operational characteristics of the Nagasaki Urban Design System and the unwritten design manners in this report. I can point out as operational characteristics that the fixed members give advice while long-term, that it is applied to both of public and private projects, that it has no guideline, that they advise after watching the site and the actual product, and that the planners who can understand this system are chosen. vertical louvers of buildings, white tones, rooftop greening and voluminous green, hiding fences, reuse of historic materials, and similar designing are unwritten design manners.

The Influence of Plant Type, Substrate and Irrigation Regime on Living Wall Performance in a Semi-Arid Climate

Living walls are fast becoming a ubiquitous feature of modern living and are widely implemented in commercial buildings in both internal and external environments. However, there are several challenges associated with maintaining healthy plant growth on these water sensitive urban design systems. This experimental study of an instrumented prototype-scale living wall has found that there is a close relationship between the plants, substrates and adopted irrigation regimes. In this study, plant selection was found to be more critical than either substrate or irrigation regime selection. This research also found that both the location of the plants on the wall and irrigation volume significantly affected the plants’ ultimate total dry weight. In particular, plants were found to grow taller on the upper section of the living wall compared to the middle and lower sections. It is recommended that particular attention should be given to plant location and the amount of irrigation water supplied at different positions on the living wall.

Flood Mitigation Performance of Permeable Pavements in an Urbanised Catchment in Melbourne, Australia (Elizabeth Street Catchment): Case Study

Permeable pavement (PP) systems have been shown to provide onsite stormwater management as well as contaminant removal benefits. Therefore, significant research has taken place in recent years to analyse the performance of these structures in terms of the volume of stormwater harvested and the water quality improvements at small scales. However, there is limited understanding of their performance for reducing stormwater runoff volume to prevent natural disasters, such as catchment-scale flooding. With larger flooding events projected to occur more frequently as a result of urbanisation and climate change, PP systems have the potential to mitigate loss by reducing peak flows and runoff volumes. Therefore, this research investigates the performance of PP at the catchment scale under a range of design rainfall and land-use scenarios. Results indicate that the integration of permeable pavements in urban settings is effective in mitigating surface flooding in an urbanised catchment in Melbourne, Australia by reducing the peak flows by 7–16%. However, in practice, flood reduction ability can markedly decrease with time due to the clogging of pavements. Our results provide preliminary data to show that the integration of permeable pavements into the existing urban landscape can reduce the risk of flooding by providing areas for water to infiltrate if maintained properly. These results are envisioned to assist councils and stormwater managers with the option evaluation of the water-sensitive urban design systems and selecting the appropriate stormwater management measures.

Formal Modeling and Verification of the Functionality of Electronic Urban Railway Control Systems Through a Case Study

This paper presents a formal model-based methodology to support railway engineers in the design of safe electronic urban railway control systems. The purpose of our research is to overcome the deficiencies of existing traditional design methodologies, namely the incompleteness and the potential presence of contradictions in the system specification resulting from non-formal development techniques. We illustrate the application of the methodology via a case study of a tram-road level crossing protection system. It was chosen partly because it has a simple architecture and a small number of elements, thus it fits the scope limitations of this article. At the same time, it is suitable for presenting all essential features of our methodology. The proposed solution provides a specification/verification environment that facilitates the construction of correct, complete, consistent, and verifiable functional specifications during the development, while hiding all the formal method-related details from the railway engineers writing the specifications. Using this formal model-based methodology, a high-quality functional specification can be achieved, which is guaranteed to be more exhaustive and will contain fewer errors than traditional development.