Dense Urban Areas Research Articles

Aging-in-Place and Home Modifications for Urban Regeneration

The rapidly growing aging population is a global phenomenon imposing societal challenges on many cities. ‘Aging-in-place’ as a popular concept accommodates both the elderly desire to age in a familiar environment and adaptive old home modifications for aging. However, this concept has not been explored in-depth systematically in the urban regeneration context. This article explores a form of aging-in-place that is suitable for large and dense residential urban areas using the case of Hong Kong as an example of a laisse-faire fast-growing dense city, with a focus on home modifications. As in many other Asian cities, with a low tax rate and without a pension scheme, the elderly in Hong Kong are concerned more with the basic needs of health care and rely on public housing. Housing affordability is the primary concern. The government is expected to take the lead in aging-in-place in urban regeneration, in particular, to provide necessary home modifications for the elderly who live in public housing with primary health care provisions. A survey of 294 respondents revealed that housing expenditures, housing size, income level, and residential location are indicators of whether home modifications or health care in cities such as Hong Kong can be afforded by the locals, under tight budget constraints.

What is the Right Size for a Residential Building Parcel Locker?

Common-carrier parcel lockers present a solution for decreasing delivery times, traffic congestion, and emissions in dense urban areas through consolidation of deliveries. Multi-story residential buildings with large number of residents, and thus a high volume of online package orders, are one of the best venues for installing parcel lockers. But what is the right size for a residential building locker that would suit the residents’ and building managers’ needs? Because of the novelty of parcel lockers, there is no clear guideline for determining the right locker size and configuration for a residential building given the resident population. A small locker would result in packages exceeding capacity and being left in the lobby, increasing the building manager’s workload and confusing and inconveniencing users. On the other hand, a large locker is more expensive, more difficult to install, and unappealing to residents. To answer this question, we installed a common-carrier parcel locker in a residential building in downtown Seattle, WA, U.S.A. Through collecting detailed data on locker usage from the locker provider company, we studied and quantified carriers’ delivery patterns and residents’ online shopping and package pickup behaviors. We then used this information to model the locker delivery and pickup process, and simulated several locker configurations to find the one that best suits the delivery needs of the building. These findings could aid urban planners and building managers in choosing the right size for residential building lockers that meet delivery demand while minimizing costs and contributing to environmental benefits.

Applicability Analysis of Trunk Drainage Sewer System for Reduction of Inundation in Urban Dense Areas

Urban development naturally aggravates flood damage, causing severe damage yearly. Preparation for flood damage is a part of urban planning, but it is not easy to establish clear mitigation measures in densely populated urban areas. This study analyzed the applicability of trunk drainage sewers as an alternative to installing abatement facilities, a typical structural measure for reducing flood damage in dense urban areas. The study areas included three areas in South Korea where flood damage had previously occurred, and the input parameters of the flood analysis model were calibrated based on the measured runoff, followed by testing with inundation traces. The results of three watersheds were qualitatively evaluated using the Lee Sallee Shape Index (LSSI) method. The applicability of the trunk drainage sewer system in the Gunja and Dowon watersheds were “Excellent” and “Good” in the Dorim watershed. The analysis results for each trunk drainage sewer condition indicated that the peak flow reduction was the greatest at 40% and 60% dimensionless upstream area ratio (DUAR) for 1000–5000 m3 and 10,000 m3, respectively. High hydrological applicability under the same rainfall conditions was demonstrated consequent to analyzing the applicability of the installation of a typical reduction facility and trunk drainage sewer.

Results of the research, development and production seminar for drilling and blasting

The article provides the results of the research, development and production seminar on drilling and blasting in surface and underground mine workings and special blasting. The seminar was organized by the Ural Association of Shotfirers (Vzryvniki Urala) and held on 26 May, 2022 on the territory of the UMMC Museum Complex in the town of Verkhnyaya Pyshma, with the participation of the Institute of Mining UB RAS and the Ural Department of Rostekhnadzor. Reports on the following topics were presented: special blasting in explosive welding of metals and explosive demolition; experience with nonexplosive mixtures and devices, including pulsed gas generators, in dense urban areas; the outcome of developing and testing the procedure of studying rock mass strength properties in the course of blasthole roller drilling in open pits; forthcoming innovations in Federal Law no. 116 on Industrial Safety of hazardous production sites; relevance, features and conditions of blasting under safety shelters; mining conditions for underground mining at the Donskay Mining and Processing Plant in Kazakhstan. The theoretical part of the seminar was followed by a tour of the exhibition centers of the UMMC Museum Complex including military and automotive museums, the “Wings of Victory” aviation exhibition, the “Ceremonial Regiment” exhibition centre, and an open exposition site with railway and artillery equipment.

Construction of Urban Green Space Network in Kashgar City, China

With the new round of western development being pushed forward and territorial spatial planning being put into place, northwest China’s urbanization rate has sped up. Urbanization will inevitably affect the city’s general landscape pattern and features, aggravating the landscape’s fragmentation and destroying the urban ecological environment. That threatens the well-being of the residents and the city’s biodiversity. Urban green space provides a habitat for the creatures in the city, and its connectivity provides corridors. Researchers and planners have developed green space networks to protect urban biodiversity and satisfy urban residents’ needs for recreation and ecologically friendly open space. This study uses RS, GIS, SeNtinel Application Platform (SNAP), and Conefor Sensinode. Applying the landscape connectivity index, least-cost path model, and corridor curvature analysis to identify potential recreation and biodiversity conservation corridors with a reasonable width, identifies good quality green space patches and corridors, or which ones need improvement. The results show that: (1) The patches selected by the possible connectivity index (PC) calculated with a threshold of 100 m in the urban area of Kashgar have higher recreational attributes. (2) There are 24 effective recreational corridors in Kashgar, with a total length of 43.44 km, and 53 effective biodiversity conservation corridors, a total of 78.23 km. Suppose recreational and ecological functions are considered to build a comprehensive green space network. The 50 m recreational corridor is mainly distributed in the center, and the 30 m biodiversity conservation corridor is primarily distributed on edge. (3) We can determine the location of the new green space suitable for protection or development by analyzing the corridor curvature. Through the constructed green space network, we can find that green space planning has severe fragmentation, unfair distribution, and other problems. Based on these issues, optimizing urban green space can promote the connectivity of urban green space. Furthermore, studying the width of corridors suitable for dense urban areas is conducive to protecting urban biodiversity and resident well-being.

Mapping daytime thermal patterns of Bologna municipality (Italy) during a heatwave: A new methodology for cities adaptation to global climate change

Remotely sensed Land Surface Temperature (LST) is widely used to characterize Surface Urban Heat Island (SUHI) intensity and spatial variability. SUHI may differ significantly from the Urban Heat Island (UHI), which is related to air temperature and is more representative of human wellbeing. The lack of information and results on UHI development is due to the difficulty in having measurements with high spatial density within the city and the uncertainties in finding relationships between air and surface temperatures. Characterizing UHI is fundamental when dealing with human thermal wellbeing especially when extreme events occur. A new index, named Urban Heatwave Thermal Index (UHTI), was presented here to quantify daytime air temperature variability patterns in an urban environment during a meteorological heatwave. UHTI integrates a) air temperature recorded by local sensors; b) structural microclimatic Envi-met fluidodynamic modeling simulations; and c) remotely sensed environmental indicators. UHTI is a reliable representation of thermal criticalities in the city for its inhabitants. A case study on Bologna (Italy) municipality is presented. Moreover, UHTI was calculated and compared with the Urban Thermal Field Variance Index (UTFVI), commonly used for urban climate characterization. Results showed a high degree of correlation (R2 = 0.795) between the two indexes; residual mapping and hot-spot detection indicated that their biggest differences are next to dense urban fabric areas like historical centers and water body areas.

Ropewalks and the linear city

Sailing ships required miles of rope for rigging, and its frequent replacement. Most ports of any size had roperies or rope manufactures that transformed hemp or other materials through combing, twisting, and tarring to produce a strong product that would resist the stresses of strain and water. A ready supply of rope supported expanding navies and merchant companies, and competition for more efficient production spurred competition between port cities. To make long lengths of rope, uninterrupted straight areas were needed close to the waterfront. Sometimes these were covered spaces, sometimes streets or walks set aside for the purpose. Ropewalks shaped ports through the creation of linear demarcations against the irregular edge where water meets land. Rope manufacture was an essential industry for ports but also a frequent site of fires that often did great damage to dense urban areas. The importance of rope as a pre-modern industry is gone yet the traces of it remain in the extended port landscape.

Исследование и разработка компонентов газогенераторных составов на основе нитрата натрия для повышения безопасности при разрушении искусственных объектов

In the process of extraction of the piece stone and in the destruction of concrete and brick buildings in dense urban areas, the issue of safety and efficiency of work is very important. For reducing the percussive action during blasting operations, various methods and means are used. Currently, when extracting block stone, the substances are used that can create pressure in the hole due to the combustion reaction in the deflagration mode. The article is devoted to the research and development of gas-generating compositions based on the sodium nitrate to improve safety during the destruction of artificial objects. Sodium nitrate was chosen as an oxidizer, this is primarily due to the low cost of sodium nitrate, low sensitivity to mechanical and detonation effects, and a significantly lower content of harmful compounds in the combustion products compared to analogues. Magnesium and carbon (from a gas mask and walnut) were used as fuel. Tests for the flammability of mixtures and thermodynamic calculations of combustion parameters were carried out to determine the optimal ratio of the initial components. It was established that a sufficiently high efficiency and uniformity of combustion are observed at a ratio of the initial components of 60 % — NaNO3, 20 % — Mg, 20 % — C. X-ray phase analysis of solid combustion products was carried out. It is shown that the main products are magnesium oxide and sodium carbonate. Field experiments on the destruction of concrete blocks were carried out. The performed studies and field tests showed high efficiency and safety of the use of the developed gas generator composition for the destruction of artificial objects, which can be used for the directed destruction of artificial objects or rocks of medium strength with a coefficient of 8 on the scale of the professor MM. Protodyakonov. The destruction of the concrete block occurred without the scattering of individual stone fragments, the formation and propagation of a shock air wave.

Landsat observation of urban growth and land use change using NDVI and NDBI analysis

Landsat observation has numerous potentials as a quantitative approach in regional scale monitoring of urban growth and environmental change. To achieve this approach, three Landsat data of year 1991 (TM), 2005 (ETM+) and 2019 (OLI-TIRS) has been acquired, classified, and accurately assessed. The research assesses spatio-temporal urban growth, its pattern and land use land cover (LULC) changes of using Normalized Difference Vegetation Index (NDVI) and Normalized Difference Building Index (NDBI) analysis. NDVI were performed for vegetation monitoring especially on loss of vegetation land while NDBI were performed for identification of dense urban and built-up areas. The NDVI and NDBI density results show a significant decreased of vegetation land and a leap up increased of urban and built-up land use. This indicates a significant rapid growth development and a vast transformation of agricultural and forest land into low density development. A rapid urban growth of regional development corridor has significant influence on environment change especially to their periphery. The utilization of both NDVI and NDBI as surrogates has the capability to provide dynamic view and improve the accuracy of land use land cover change analysis. The study showed urban growth has quadrupled from 1991 to 2019 with most rapid growth was from 1991 to 2005 due to greater low-density development and a discontinue growth pattern in the past years compare with much sustainable higher-density development in the recent years.

Development of methodological approaches to conducting monitoring of traffic noise and its assessment using acoustic modelling methods

Introduction. At present, considerable attention is paid to the problems of noise pollution in urban and rural settlements. Transport is the main source of noise in the structure of complaints about unfavourable living conditions in dense urban areas. Material and methods. Materials for selecting the most significant criteria or grouping the objects of surveillance were in situ instrumental measurements of noise levels and the results of acoustic calculations obtained during the processing of an acoustic model. In situ measurements of noise levels were made in St. Petersburg on the territory of residential areas. The acoustic models were built using the software “Acoustics 3D”. Noise source parameters were set according to the data obtained during field measurements. Results. During the development of methodological approaches, the criteria for grouping the objects of surveillance were defined. In accordance with the selected criteria, were formed 8 surveillance groups. As a result of the measurements, the difference in noise levels between the typical points within the group was no found to exceed 2 dB. To verify the developed criteria here acoustic modelling was performed. Limitations. On the territory of St. Petersburg over the year, study included one thousand measurements. Conclusion. The developed criteria make it possible to expand the list of control objects while reducing labour costs for conducting socio-hygienic monitoring, while maintaining the objectivity of the results of the acoustic pollution levels of the territory.

Mobile charging stations for EV charging management in urban areas: A case study in Chattanooga

The advancement of fixed charging stations (FCS) has facilitated electric vehicle (EV) charging and increased EV adoption. FCSs are especially important in dense urban areas, where home charging is not an option. However, FCSs’ construction is limited by budget, fragile power grid infrastructure, and site constraints, among others. Therefore, suitable locations for building FCSs are limited. Even in the presence of FCSs, EV drivers face challenges such as long charging times and inconvenient charging locations. Mobile charging stations (MCS), which allow for scheduling and convenient charging, can be a supplementary charging technology to address these shortcomings and allow rapid expansion of charging infrastructure, assuming the MCS can be scheduled efficiently. This paper develops an optimization framework for the optimal charging management of EVs considering a multi-charger system integrating different types of FCSs and MCSs. Considering the EV driver’s travel trajectory and time value, the proposed framework finds the optimal charging technology and location to minimize the EV user’s overall charging cost and time. The model is implemented in Chattanooga, TN, USA, where the evaluation results demonstrated that MCSs are the optimal charging method for many EV users. Moreover, the results indicated that MCS mitigates the power grid stress caused by EV charging during peak hours.

Mitigating Effect of Urban Green Spaces on Surface Urban Heat Island during Summer Period on an Example of a Medium Size Town of Zvolen, Slovakia

Climate change affects the urban population’s health and quality of life. Urban green spaces (UGS) underpin several essential ecosystem services, amongst them climate regulation. Urban vegetation mitigates high temperatures and, thus, reduces the heat stress for urban residents. The study aimed to verify whether the Surface Urban Heat Island (SUHI) effect manifests itself even in a medium size town (Zvolen, Slovakia) surrounded by agricultural and forested landscape and to quantify the temperature mitigating effect of urban green spaces. Land surface temperature (LST) and SUHI distribution were derived from the Landsat data during the summer months of 2010–2021. To statistically prove the cooling effect of the urban vegetation, we tested (by one-way ANOVA) LST within three urban zones of the Zvolen municipality defined by the Copernicus imperviousness density data: (a) dense urban area (31–100% impervious surfaces), (b) discontinuous urban area (1–30% impervious surfaces), (c) urban green spaces (0% impervious surfaces), and the open land surrounding the town (0% impervious surfaces). The results showed a statistical difference in temperatures between all urban areas (all zones) and the open land. Moreover, the UGS temperature was statistically different compared to the other urban zones. The mean temperature difference through the years 2010–2021 between urban green spaces and the dense urban area was 3.5 °C, with a maximum of 4.9 °C and a minimum 1.7 °C in favor of the urban spaces. Moreover, the temperature of urban green spaces and open land varied during the studied summer period. The warmer the weather, the higher the difference, while at the end of August, on a notably colder day, there was no significant difference between them. The results confirmed that UGS are significantly cooler during hot days, and they can mitigate the local climate.

Joint routing of conventional and range-extended electric vehicles in a large metropolitan network

Range-extended electric vehicles combine the higher efficiency and environmental benefits of battery-powered electric motors with the longer mileage and autonomy of conventional internal combustion engines. This combination is particularly advantageous for time-constrained delivery routing in dense urban areas, where battery recharging along routes can be too time-consuming to economically justify the use of all-electric vehicles. However, switching from electric to conventional fossil fuel modes also results in higher costs and emissions and lower efficiency. This paper analyzes this heterogeneous vehicle routing problem and describes two solution methods: an exact branch-price-and-cut algorithm and an iterated tabu search metaheuristic. From a methodological perspective, we find that the exact algorithm consistently obtains tight lower bounds that also serve to certify the metaheuristic solutions as near-optimal. From a policy standpoint, we examine a large-scale real-world case study concerning parcel deliveries in the Chicago metropolitan area and quantify various operational metrics including energy costs and vehicle miles traveled. We find that by deploying roughly 20% of range-extended vehicles with a modest all-electric range of 33 miles, parcel distributors can save energy costs by up to 17% while incurring less than 0.5% increase in vehicle miles traveled. Increasing the range to 60 miles further reduces costs by only 4%, which can alternatively be achieved by decreasing the average service time by 1 minute or increasing driver working time by 1 hour. Our study reveals several key areas of improvement on which vehicle manufacturers, distributors, and policy makers can focus their attention.

Calculation-theoretical justification of the compensation grouting parameters for the metropolitan railway protection from sedimentary deformations

An increase in the volume and scale of underground space development, including the construction of metropolitan railway facilities in large cities, is accompanied by a significant impact on the surrounding urban development, which requires the development and implementation of a set of special measures to protect buildings and structures from excess deformations. At the same time, numerous above-ground and underground structures are involved in the area of influence of the construction, including existing metropolitan railway facilities, as well as residential buildings and above-ground transport facilities. Сurrently, one of the most effective methods that provide reliable facilities protection from sedimentary deformations is the compensation grouting method. The article outlines the theoretical foundations for the use of compensation grouting technology to protect buildings and structures from excess sedimentary deformations during the construction of transport infrastructure facilities in dense urban areas. A mathematical model has been developed that corresponds to the actual geometry of the computational area of the metropolitan railway lobby with a soil base, the actual physical and mechanical characteristics of the materials of its structures, and the soil mass. The article presents the computer modeling results, with its help determined volumes, pressure, sequence, and injection sites. Based on calculated data, the duration of the special solution compensatory injection was determined to maintain a stable position of the foundations of the metropolitan railway escalator tunnels by forming the calculated stress-strain state of the soil mass at the ground slab base of the structure to provide a given preventive lift, the dependences of the lift deformations on pressure and the grouting volumes of special mixtures were established. Based on the obtained data, a procedure was developed for the production of work to maintain the planned-altitude position of metropolitan railway facilities at all construction stages and operation of the multifunctional complex.

ENERGY AND LIFE CYCLE COST SAVING POTENTIAL OF BUILDINGS USING GREEN WALLS: A CASE STUDY FROM SRI LANKA

ABSTRACT With its numerous benefits, the concept of green walls can be used as one of the solutions to address global warming and climatic changes while improving the natural vegetation in dense urban areas. However, perception about the initial and maintenance cost of green walls along with lack of awareness about operational cost savings seems to influence the slow uptake of green wall applications. In that context, this research aimed to assess the Life Cycle Cost (LCC) of green walls in comparison to a conventional wall towards exploring the operational cost benefits which are the most convincing decision criteria for clients/investors. The study involved a case study analysis of an indirect green façade and a comparative conventional wall. The data required to perform the LCC analysis were collected through documentary reviews and on-site temperature measurements. The analysis shows that the initial cost of a green wall is 15% higher than a comparable conventional wall. However, operational and maintenance costs of green walls result in 64% and 25% savings due to potential energy cost-saving, and minimum external redecoration time interval, respectively. This results in an overall LCC saving of 45% over conventional walls with a reasonably expected lifetime of fifty years. As a departing point of previous studies, this study provides empirical evidence on the LCC of green walls in comparison to a conventional wall in a residential facility, from a tropical climate perspective.

Architecture of Air Transport Medicine Facilities

The article is devoted to the study of the organization of air medicine and the architectural design of helipads in hospitals located in an urban environment. Also, the article has an attempt to draw public attention to the inevitable development of air medical aviation as a new and promising type of emergency medical transport in dense urban areas, which, in the processes of urbanization, will be aggravated by blocking the possibility of automobile movement in the city. The purpose of the article is to analyze the main problems and difficulties that accompany the design and operation of medical helipads in an urban environment, as well as to propose and systematize the main features and parameters that must be considered when designing helipads in hospitals. Methodology: the study consists of a systematic, and comprehensive analysis of the problems of architectural design of hospital helipads. The study used the analysis of literary, normative, informational sources, graphic-analytical methods, photographs and field research. The research methodology consists of a set of methods of practical, theoretical, empirical, retrospective and factor analysis. Conclusions: when designing a heliport in a hospital, it is essential to provide the shortest and safest route for a patient to the intensive care unit or operating room. Helipads for medical use are best located directly on the hospital grounds (on the roof of a hospital building or outbuilding, on the ground). It is also necessary to take into account the presence of a network of public heliports, which will create the possibility of landing and takeoff of medical helicopters in different parts of the urban space.

Vector Tracking Based on Factor Graph Optimization for GNSS NLOS Bias Estimation and Correction

Position and location constitute critical context for Internet of Things (IoT) devices. Global navigation satellite systems (GNSSs) are the primary apparatus providing precise position and location information for IoT devices in outdoor environments. However, in dense urban areas, non-line-of-sight (NLOS) signals will induce large errors in GNSS pseudorange measurements due to the additional signal transmission paths. The vector tracking (VT) technique utilizing a Kalman filter (KF) to estimate navigation solutions has been investigated in NLOS detection, and its advantages have been demonstrated. However, the estimation of NLOS-induced bias has not been thoroughly investigated in the VT framework. In this article, we focus on the estimation and correction of NLOS-induced errors within the VT framework. First, graph optimization (GO) instead of a KF is incorporated with VT to optimize the estimation of navigation solutions. The NLOS-induced bias is then added to the VT state vector as the variable for real-time estimation. Compared with the KF-VT method, in GO-VT, the state transformation and the measurement model are regarded as constraints to optimize the state vector estimation. Hence, the GO-VT framework is more flexible than the KF approach in dealing with state vector changes. An iterative process is conducted to solve for the optimization results; a multiple-correlator scheme is employed in GO-VT to provide the initial values of the NLOS-induced bias. Three collected GPS L1 data sets (static and dynamic) are used to evaluate the proposed method. The statistical results support the conclusion that GO-VT with state augmentation achieves superior position estimation in urban areas.

NB-IoT Coverage and Sensor Node Connectivity in Dense Urban Environments: An Empirical Study

Wireless sensor networks have enabled smart infrastructures and novel applications. With the recent roll-out of Narrowband IoT (NB-IoT) cellular radio technology, wireless sensors can be widely deployed for data collection in cities around the world. However, empirical evidence regarding the coverage and connectivity of NB-IoT in dense urban areas is limited. This article presents an empirical study that focuses on evaluating the coverage and connectivity of NB-IoT in a dense urban environment. We have designed an NB-IoT sensor node and deployed over 100 of them in high-rise apartment buildings in Hong Kong. These sensor nodes utilize a commercial NB-IoT network to collect high-resolution water flow data for machine learning model training and provide timely feedback to users. We collect and analyze the empirical NB-IoT signal measurements from the sensor nodes deployed in various challenging outdoor and indoor environments for over three months. These empirical measurements reveal correlations between NB-IoT connectivity and sensor installation environments. We also observe that inter-cell interference, as a result of coverage by multiple neighboring NB-IoT cells in a dense urban environment, is a source of connectivity degradation. We discuss potential issues that IoT application designers and system integrators might encounter in practical NB-IoT devices deployment, and we propose a transmission decision algorithm based on signal measurements for mitigating energy wasted due to transmission failures. Finally, we demonstrate the results and the benefits of using high-resolution water flow data collected by our purpose-built NB-IoT sensor nodes for studying the patterns of domestic water consumption in Hong Kong.

Towards globally relevant, small-footprint dewatering solutions: Optimal conditioner dose for highly variable blackwater from non-sewered sanitation

Globally, the sanitation needs of three billion people are met by non-sewered sanitation. Small-footprint treatment technologies are needed that are appropriate for dense urban areas. Blackwater (BW) (or fecal sludge), contains more than 95% liquid, and dewatering it without conditioning requires large footprints. Chemically-enhanced dewatering with conditioners is a promising option to increase dewatering performance and reduce required footprints. However, before implementation of this solution there is a need for increased knowledge on selection and dosing of conditioners. This study evaluated bio-based and synthetic conditioners (chitosan, tannin-, and starch-based, synthetic with and without poly-acrylamide) with 14 types of BW from five countries. The supernatant after settling with jar-tests was analyzed to quantify optimal dose and dewatering performance. The reduction of total chemical oxygen demand (COD) was >55%, achieved by removal of particulate constituents with mainly soluble COD remaining in the supernatant. A reduction in particulate COD could lead to increased efficiency of soluble COD in supernatant treatment. Bio-based conditioners are as effective as synthetic conditioners, and when performance was variable, it was due to differing properties of TSS, TS, EC and pH. Optimal conditioner dose for synthetic conditioners and chitosan could be predicted using concentrations of total solids (TS) (R2 > 0.7), whereas optimal dose for starch- and tannin-based conditioners could be predicted with electrical conductivity (EC) (R2 > 0.8), and colloid titration (R2 > 0.8). In addition, real-time optical TSS and EC sensors could accurately predict chitosan dose for fresh BW treated at source (R2 = 0.97, R2 = 0.95). This study validates that use of conditioners for dewatering with highly variable BW can be implemented with real-time measurements for optimal dose, in globally relevant implementations.

Single- and Multiagent Actor–Critic for Initial UAV’s Deployment and 3-D Trajectory Design

This article considers a wireless network consisting of unmanned aerial vehicles (UAVs), deployed as aerial base stations, and a large number of terrestrial users randomly distributed in a dense urban area. The main objective of this work is to maximize the downlink rate of users along with clustering of users and 2-D initial placement of UAVs, which effectively minimizes the clustering error. To achieve this goal, we estimate the next users’ locations with deep echo-state network (ESN) to find the movement pattern of users with high accuracy. Then, we propose the single- and multiagent actor–critic (AC) algorithms for UAVs’ initial deployment and trajectory design, where the multiagent scheme employs an efficient bandwidth allocation. Simulation results supported by a real data set of the terrestrial users’ coordinates indicate that, when the deep ESN algorithm is used, the accuracy is 93.75% for longitude and 88.36% for latitude compared to the simple ESN performance. Moreover, the use of single- and multiagent AC algorithms display better performance in terms of downlink rate and convergence speed than value-based algorithms such as deep <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -network schemes.