Challenging Urban Environment Research Articles

Bucharest – the role of spatial planning in a challenging urban environment

Bucharest, Romania’s dynamic capital of over 1.7 million people, grapples with complex urban challenges deeply rooted in its history. In six centuries, the city has witnessed foreign occupations, natural disasters, as well as radical structural transformations during the Communist era. Today, Bucharest faces challenges similar to other post-socialist cities, such as uncontrolled suburbanization or traffic congestion. Registering significant economic growth in the last fifteen years, the city seeks to harness its potential, using innovative urban planning to create a more competitive and liveable European capital.

Feather corticosterone reveals that urban great tits experience lower corticosterone exposure than forest individuals during dominance-rank establishment

Although the consequences of urbanization for the physiological health of animals are the focus of much active research, an overlooked aspect is how physiology could be indirectly modulated by the urban environment via changes in intraspecific behavioural interactions, particularly among gregarious species. Both urbanization and the establishment, as well as maintenance, of hierarchical rank position are processes that could incur physiological stress. Measurements of glucocorticoids (GCs) in relation to urbanization, however, have yielded inconsistent results. In most cases, GCs have been measured in blood, offering only a 'snapshot' of an animal's current physiological state. Because circulating GCs are incorporated into growing feathers or hair, measurements of feather/hair GCs offer a longer term measure of stress exposure reflecting the whole period of feather/hair growth. During two calendar years, we collected tail feathers from 188 urban and forest great tits (P. major) across multiple sampling sites and analysed corticosterone (CORT-the main GC in birds) levels, reflecting CORT exposure during the extended period in late summer and early autumn when great tits moult and winter flocks are formed. Urban individuals exhibited consistently lower feather CORT (fCORT) levels than forest birds indicating lower overall exposure to CORT during this period. The lower fCORT levels in urban individuals could represent an adaptation to cope with the more challenging urban environment, physiological constraints on stress axis function or a trade-off between the ability to respond to stressors and predation risk during moult. Despite the expectation that CORT responses to urbanization are highly context-dependent, the spatial consistency of our results and agreement with a multi-population study of fCORT in European blackbirds (Turdus merula) suggests a generalization of the effect of urbanization on CORT exposure during post-breeding moult (i.e. not site- or species-specific).

“A simple post-growth life”: The Green Camp Gallery Project as Lived Ecotopia in Urban South Africa

ABSTRACT Utopias in Africa is an emerging academic field. While we are witnessing an increasing number of fictional and ideological utopias, little attention is paid to lived utopias. The Green Camp Gallery Project is such a lived utopia, which predominantly strives for realizing desired future imaginations in daily practices. Localized in the urban context of Durban (South Africa), in a derelict house in the industrial area, the Green Camp strives for a “simple post-growth life,” which is closely related to nature and the philosophy of Ubuntu. In so doing, the Green Camp responds to the overlapping crisis of urbanity and offers an alternative future aspiration. The Green Camp is not perfect and it is not able to solve the deep problems of South African society, but it offers an “island” of hope and imagination in a challenging urban environment. At the same time the lived utopia reveals the agency of the urban marginalized and contradicts widespread assumptions concerning environmentalism. Based on a qualitative study, the article takes an unusual perspective by analyzing the imagination of lived utopia in an emerging utopian hotspot—Africa.

BIKES: Bicycle Itinerancy Kalman Filter With Embedded Sensors for Challenging Urban Environment

The use of bicycles is regaining popularity, especially in city centers where they can be used as quickly as cars and reduce carbon footprint. However, in these dense urban environments, navigation methods based on GNSS technologies do not provide sufficient accuracy for cyclist navigation and safety. To mitigate the challenges of indoor-like surroundings, a new positioning algorithm: BIKES (Bicycle Itinerancy Kalman filter with Embedded Sensors) was developed. This extended Kalman filter processes deeply degraded GNSS data to update velocity and position estimates with differential computation approaches working even in degraded environments. GNSS signals are combined with inertial and magnetic data to continuously estimate the trajectory when GNSS is unavailable. BIKES’ performance was tested in real-life conditions on a 3 km long path in the city center downtown Nantes and compared to Google Fused Location Provider estimates. A mean positioning error below 1 m with a 0.5 m standard deviation is achieved. These results are 4 times better than the Google solution. This algorithm allows also distinguishing if the cyclist is riding on a bike path, the sidewalk, or the road, which is critical for guidance systems.

Monocular Visual-Inertial-Wheel Odometry Using Low-Grade IMU in Urban Areas

In this article, we propose a new methodology to fuse visual-inertial measurements for land vehicles in a challenging urban environment in which a GNSS signal is not available nor reliable. Motivated by a degenerate case caused by a large bias of a MEMS IMU, we redesign a system model of visual-inertial odometry in a framework of extended Kalman filter. In particular, the system model is propagated through a reduced inertial sensor system composed of a 3-axis gyroscope, a 2-axis accelerometer, and a single-axis odometer. An analytical observability derivation reveals unobservable bases of our estimator, and these directions are resolved by using intermittent position measurements from a GNSS receiver. Furthermore, we inspect the uncertainties of the state vector in a Monte-Carlo simulation that agrees with our theoretical results. The proposed method is validated through the KITTI benchmark dataset and an extensive field testing showing a position drift as 1.25% in tunnels on average and a mean position error of 2.81m in the street canyon over a 6.7km driving.

Modeling evidential grids using semantic context information for dynamic scene perception

Uncertainty about urban environments stems not only from imprecise pose estimation and noisy information in images but also from the lack of semantic information. This article presents an approach to improve the perception capability of intelligent vehicles in complex urban environments. The new method uses the meta-knowledge extracted from semantic context images associated with depth information to model occupancy grids from stereo vision. It uses the evidential formalism of the Dempster–Shafer theory to manage uncertainties involved in grid discretization, partial observation of the environment and also dynamic elements present in the scene. Real experiments carried out in a challenging urban environment using the KITTI benchmark are reported, from which meaningful evaluations compared to the standard evidential grid are done to show that the proposed method is able to better handle semantic, dynamic and uncertainty aspects in the environment representation.

Improving GPS Code Phase Positioning Accuracy in Urban Environments Using Machine Learning

The accuracy of location information, mainly provided by the global positioning system (GPS) sensor, is critical for Internet-of-Things applications in smart cities. However, built environments attenuate GPS signals by reflecting or blocking them resulting in some cases multipath and non-line-of-sight (NLOS) reception. These effects cause range errors that degrade GPS positioning accuracy. Enhancements in the design of antennae and receivers deliver a level of reduction of multipath. However, NLOS signal reception and residual effects of multipath are still to be mitigated sufficiently for improvements in range errors and positioning accuracy. Recent machine learning-based methods have shown promise in improving pseudorange-based position solutions by considering multiple variables from raw GPS measurements. However, positioning accuracy is limited by low accuracy signal reception classification. Unlike the existing methods, which use machine learning to directly predict the signal reception classification, we use a gradient boosting decision tree (GBDT)-based method to predict the pseudorange errors by considering the signal strength, satellite elevation angle and pseudorange residuals. With the predicted pseudorange errors, two variations of the algorithm are proposed to improve positioning accuracy. The first corrects pseudorange errors and the other either corrects or excludes the signals determined to contain the effects of multipath and NLOS signals. The results for a challenging urban environment characterized by high-rise buildings on one side, show that the 3-D positioning accuracy of the pseudorange error correction-based positioning measured in terms of the root mean square error is 23.3 m, an improvement of more than 70% over the conventional methods.

Carved in Stone: Field Trials of Virtual Reflectance Transformation Imaging (V-RTI) in Classical Telmessos (Fethiye)

ABSTRACT Virtual Reflectance Transformation Imaging (V-RTI) is a hybrid method that combines 3D, Virtual Reality (VR) and 2D+ technologies into a rapid, lightweight, and user-friendly method of recording archaeological monuments in the field. The resultant image file can be interactively lit from various positions to highlight surface texture and detail not generally visible to the naked eye. In this article, we describe the V-RTI method and critically compare it to the current standard Highlight (H-RTI) method. We present results of a field trial of V-RTI in a challenging urban environment that yielded a new inscription, new readings, and epigraphic palimpsests that significantly change our understanding of the ancient Lycian city of Telmessos. We conclude that V-RTI is a valuable new tool for recording at-risk heritage worldwide and should be considered a default recording tool for field survey and conservation for many different classes of field monument.

Ground Vehicle Navigation in GNSS-Challenged Environments Using Signals of Opportunity and a Closed-Loop Map-Matching Approach

A ground vehicle navigation approach in a global navigation satellite system (GNSS)-challenged environments is developed, which uses signals of opportunity (SOPs) in a closed-loop map-matching fashion. The proposed navigation approach employs a particle filter that estimates the ground vehicle’s state by fusing pseudoranges drawn from ambient SOP transmitters with road data stored in commercial maps. The problem considered assumes the ground vehicle to have a priori knowledge about its initial states as well as the position of SOPs. The proposed closed-loop approach estimates the vehicle’s states for subsequent time as it navigates without the GNSS signals. In this approach, a particle filter is employed to continuously estimate the vehicle’s position and velocity along with the clock error states of the vehicle-mounted receiver and SOP transmitters. The simulation and experimental results with cellular long-term evolution (LTE) SOPs are presented, evaluating the efficacy and accuracy of the proposed framework in different driving environments. The experimental results demonstrate a position root-mean-squared error (RMSE) of: 1.6 m over a 825-m trajectory in an urban environment with five cellular LTE SOPs, 3.9 m over a 1.5-km trajectory in a suburban environment with two cellular LTE SOPs, and 3.6 m over a 345-m trajectory in a challenging urban environment with two cellular LTE SOPs. It is demonstrated that incorporating the proposed map-matching algorithm reduced the position RMSE by 74.88%, 58.15%, and 46.18% in these three environments, respectively, from the RMSE obtained by an LTE-only navigation solution.

A SYSTEMATIC COMPARISON OF DIRECT AND IMAGE-BASED GEOREFERENCING IN CHALLENGING URBAN AREAS

Abstract. Image-based mobile mapping systems enable an efficient acquisition of georeferenced image sequences, which can be used for geo-data capture in subsequent steps. In order to provide accurate measurements in a given reference frame while e.g. aiming at high fidelity 3D urban models, high quality georeferencing of the captured multi-view image sequences is required. Moreover, sub-pixel accurate orientations of these highly redundant image sequences are needed in order to optimally perform steps like dense multi-image matching as a prerequisite for 3D point cloud and mesh generation. While direct georeferencing of image-based mobile mapping data performs well in open areas, poor GNSS coverage in urban canyons aggravates fulfilling these high accuracy requirements, even with high-grade inertial navigation equipment. Hence, we conducted comprehensive investigations aiming at assessing the quality of directly georeferenced sensor orientations as well as the expected improvement by image-based georeferencing in a challenging urban environment. Our study repeatedly delivered mean trajectory deviations of up to 80 cm. By performing image-based georeferencing using bundle adjustment for a limited set of cameras and a limited number of ground control points, mean check point residuals could be lowered from approx. 40 cm to 4 cm. Furthermore, we showed that largely automated image-based georeferencing is capable of detecting and compensating discontinuities in directly georeferenced trajectories.

A SYSTEMATIC COMPARISON OF DIRECT AND IMAGE-BASED GEOREFERENCING IN CHALLENGING URBAN AREAS

Image-based mobile mapping systems enable an efficient acquisition of georeferenced image sequences, which can be used for geo-data capture in subsequent steps. In order to provide accurate measurements in a given reference frame while e.g. aiming at high fidelity 3D urban models, high quality georeferencing of the captured multi-view image sequences is required. Moreover, sub-pixel accurate orientations of these highly redundant image sequences are needed in order to optimally perform steps like dense multi-image matching as a prerequisite for 3D point cloud and mesh generation. While direct georeferencing of image-based mobile mapping data performs well in open areas, poor GNSS coverage in urban canyons aggravates fulfilling these high accuracy requirements, even with high-grade inertial navigation equipment. Hence, we conducted comprehensive investigations aiming at assessing the quality of directly georeferenced sensor orientations as well as the expected improvement by image-based georeferencing in a challenging urban environment. Our study repeatedly delivered mean trajectory deviations of up to 80 cm. By performing image-based georeferencing using bundle adjustment for a limited set of cameras and a limited number of ground control points, mean check point residuals could be lowered from approx. 40 cm to 4 cm. Furthermore, we showed that largely automated image-based georeferencing is capable of detecting and compensating discontinuities in directly georeferenced trajectories.

Soma in the City: How does listening and responding to a ‘somatic podcast’ affect one’s relationship to urban space?

Abstract This article describes a small piece of research carried out as part of an MA in Dance and Somatic Well–being at the University of Central Lancashire. The basis of the research was: a) An interest in bridging the gulf between somatic perceptual/movement practice and being in a challenging urban environment. b) Curiosity in how using digital technology can possibly create more, rather than less, connection to psychophysical self and environment. It assumed embodied person–environment mutuality and reciprocity, and was influenced by ecopsychology, the value of attending to movement, and by the somatic practices, particularly the Alexander Technique. The research methodology is influenced by Moustakas’ heuristic approach and involved an embodied first–person practice–led development of the content of the podcast. There were six participants and research ‘data’ was drawn from the time we shared together ‘post–podcast’. Conclusions were drawn from extracting themes from the subjective experience of the individuals.

Mapping Urban Tree Species Using Very High Resolution Satellite Imagery: Comparing Pixel-Based and Object-Based Approaches

We assessed the potential of multi-spectral GeoEye imagery for biodiversity assessment in an urban context in Bangalore, India. Twenty one grids of 150 by 150 m were randomly located in the city center and all tree species within these grids mapped in the field. The six most common species, collectively representing 43% of the total trees sampled, were selected for mapping using pixel-based and object-based approaches. All pairs of species were separable based on spectral reflectance values in at least one band, with Peltophorum pterocarpum being most distinct from other species. Object-based approaches were consistently superior to pixel-based methods, which were particularly low in accuracy for tree species with small canopy sizes, such as Cocos nucifera and Roystonea regia. There was a strong and significant correlation between the number of trees determined on the ground and from object-based classification. Overall, object-based approaches appear capable of discriminating the six most common species in a challenging urban environment, with substantial heterogeneity of tree canopy sizes.

Electric Bicycles as a New Active Transportation Modality to Promote Health

Electrically assisted bicycles (EAB) are an emerging transportation modality favored for environmental reasons. Some physical effort is required to activate the supporting engine, making it a potential active commuting option. We hypothesized that using an EAB in a hilly city allows sedentary subjects to commute comfortably, while providing a sufficient effort for health-enhancing purposes. Sedentary subjects performed four different trips at a self-selected pace: walking 1.7 km uphill from the train station to the hospital (WALK), biking 5.1 km from the lower part of town to the hospital with a regular bike (BIKE), or EAB at two different power assistance settings (EAB high, EAB std). HR, oxygen consumption, and need to shower were recorded. Eighteen sedentary subjects (12 female, 6 male) age 36 ± 10 yr were included, with V·O 2max of 39.4 ± 5.4 mL·min(-1)·kg(-1). Time to complete the course was 22 (WALK), 19 (EAB high), 21 (EAB std), and 30 (BIKE) min. Mean %V·O 2max was 59.0%, 54.9%, 65.7%, and 72.8%. Mean %HRmax was 71.5%, 74.5%, 80.3%, and 84.0%. There was no significant difference between WALK and EAB high, but all other comparisons were different (P < 0.05). Two subjects needed to shower after EAB high, 3 needed to shower after WALK, 8 needed to shower after EAB std, and all 18 needed to shower after BIKE. WALK and EAB high elicited 6.5 and 6.1 METs (no difference), whereas it was 7.3 and 8.2 for EAB std and BIKE. EAB is a comfortable and ecological transportation modality, helping sedentary people commute to work and meet physical activity guidelines. Subjects appreciated ease of use and mild effort needed to activate the engine support climbing hills, without the need to shower at work. EAB can be promoted in a challenging urban environment to promote physical activity and mitigate pollution issues.

Hiplife, Cultural Agency and the Youth Counter-Public in the Ghanaian Public Sphere

In Ghana globalization is transforming society and creating a challenging urban environment for youth: high unemployment, seemingly unstoppable cultural erosion, and a harsh disparity between personal ambition and opportunities for advancement. Structural transformation has relegated youth to the margins of society. This article examines ‘hiplife’, a growing Ghanaian youth musical genre that fuses American hip hop and Ghanaian highlife, as a dynamic intersection of these trends. This article shows that hiplife forms the foundation of a distinct youth counter-public, giving youth a unique platform to project their voice into the public sphere and challenge the exclusion of the dominant adult public. Ultimately, hiplife strengthens the public sphere through the generation of public discourse. Through an examination of the hiplife movement in an economic, political and social context, this article demonstrates both the experience of socio-cultural change and the agency of youth as a force behind socio-cultural change.

Mothering young children with disabilities in a challenging urban environment.

This study examined the occupations of mothering very young children with physical disabilities. Two single, urban, Black mothers in their mid-20s were interviewed with a semistructured protocol. The audiotaped, transcribed data were analyzed with a phenomenological method. The context of the challenging urban environment was a constant influence that shaped the participants' occupations of mothering. The major over-arching theme derived from the data was that mothering was "what I got to do" in relation to their particular child. Two sub-themes were identified: (a) mothering as caring and (b) the impact of social supports on the occupations of mothering. To plan meaningful, effective interventions, occupational therapy practitioners need to understand the context in which mothering occupations occur and to ensure that mothers' caring occupations and social support needs are addressed in the therapeutic partnership.