scholarly journals Prediction limits of mobile phone activity modelling

2017 ◽  
Vol 4 (2) ◽  
pp. 160900 ◽  
Author(s):  
Dániel Kondor ◽  
Sebastian Grauwin ◽  
Zsófia Kallus ◽  
István Gódor ◽  
Stanislav Sobolevsky ◽  
...  
Keyword(s):  
Mobile Phone ◽  
Spatial Scales ◽  
Urban Environments ◽  
Full Spectrum ◽  
Left Behind ◽  
Social Events ◽  
Prediction Limits ◽  
Spatio Temporal ◽  
City Structure ◽  
The City

Thanks to their widespread usage, mobile devices have become one of the main sensors of human behaviour and digital traces left behind can be used as a proxy to study urban environments. Exploring the nature of the spatio-temporal patterns of mobile phone activity could thus be a crucial step towards understanding the full spectrum of human activities. Using 10 months of mobile phone records from Greater London resolved in both space and time, we investigate the regularity of human telecommunication activity on urban scales. We evaluate several options for decomposing activity timelines into typical and residual patterns, accounting for the strong periodic and seasonal components. We carry out our analysis on various spatial scales, showing that regularity increases as we look at aggregated activity in larger spatial units with more activity in them. We examine the statistical properties of the residuals and show that it can be explained by noise and specific outliers. Also, we look at sources of deviations from the general trends, which we find to be explainable based on knowledge of the city structure and places of attractions. We show examples how some of the outliers can be related to external factors such as specific social events.

Dietary choices in a generalist herbivore, the eastern cottontail Sylvilagus floridanus, in urban landscapes

Behaviour ◽  
2021 ◽  
pp. 1-19
Author(s):  
Mohammad A. Abu Baker ◽  
Sara E. Emerson ◽  
Jessica Gorman ◽  
Joel S. Brown
Keyword(s):  
Spatial Scales ◽  
Urban Environments ◽  
College Campuses ◽  
High Protein ◽  
Urban Landscapes ◽  
Sylvilagus Floridanus ◽  
Generalist Herbivore ◽  
Left Behind ◽  
Dietary Choices ◽  
Midwestern Usa

Abstract We tested for dietary choices of foods varying in nutrient composition by cottontail rabbits on two college campuses in midwestern USA. We quantified choices among pellets of varying nutritional quality at artificial food patches. Dietary choices differed between seasons and locations. Spring giving-up densities (GUDs: food left behind) did not show differences in food choices and were lower than summer GUDs. In Appleton, the cottontails favoured both high protein and fibre pellets, whereas the medium protein and fibre pellets were favoured in Chicago. The cottontails maintained their choice of high protein, high fibre pellets at three spatial scales. The cottontails varied food intake to balance their protein, salt and fibre needs at different times and locations. Studying dietary choices and the effect of resource quality on foraging responses by urban wildlife provides a useful tool to study ecological interactions and can help minimize damage in urban environments such as parks.

scholarly journals Urban tree pests and natural enemies respond to habitat at different spatial scales

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Sarah E Parsons ◽  
Steven D Frank
Keyword(s):  
Natural Enemies ◽  
Spatial Scales ◽  
Structural Complexity ◽  
Urban Environments ◽  
Urban Trees ◽  
Urban Habitat ◽  
Urban Tree ◽  
Impervious Cover ◽  
Enemies Hypothesis ◽  
The City

Abstract Trees provide many ecosystem services in our urban environments. However, city trees are often stressed by pests that are typically higher than those in nearby natural areas. Our research highlights a potential mismatch in scale between the habitat elements that affect the densities of pests and their natural enemies on city trees. We tested a well-known ecological concept, the enemies hypothesis, in the city, where relationships of pests and their enemies have not been thoroughly studied. To test our hypothesis that natural enemies and aphid predation services on urban trees increase with more local structural complexity around trees, we collected data on crape myrtle trees on NC State University’s campus from 2016 to 2017. We measured local structural complexity of vegetation around study trees, quantified impervious cover among other urban habitat elements, collected crape myrtle aphids (Tinocallis kahawaluokalani) and their natural enemies on trees, and performed predation experiments. We found that aphid abundance was positively correlated with more impervious cover within 100 m of crape myrtle trees. Alternatively, greater local structural complexity within the 10 × 10 m area around crape myrtles correlated with a higher abundance of natural enemies. Aphid predation was mostly predicted by local structural complexity and impervious cover within 20 m of crape myrtle trees. Together, these findings suggest that although the impervious nature of our cities may mean higher densities of some pests, local landscapes around trees can play an important role in maintaining natural enemies and predation services that help regulate pest populations.

scholarly journals The time geography of segregation during working hours

2018 ◽  
Vol 5 (10) ◽  
pp. 180749 ◽  
Author(s):  
Teodoro Dannemann ◽  
Boris Sotomayor-Gómez ◽  
Horacio Samaniego
Keyword(s):  
Mobile Phone ◽  
Working Hours ◽  
Activity Space ◽  
Time Geography ◽  
Detection Algorithms ◽  
Spatio Temporal ◽  
Commuting Distances ◽  
Strong Segregation ◽  
The City ◽  
Randomization Analysis

While segregation is usually evaluated at the residential level, the recent influx of large streams of data describing urbanites’ movement across the city allows to generate detailed descriptions of spatio-temporal segregation patterns across the activity space of individuals. For instance, segregation across the activity space is usually thought to be lower compared with residential segregation given the importance of social complementarity, among other factors, shaping the economies of cities. However, these new dynamic approaches to segregation convey important methodological challenges. This paper proposes a methodological framework to investigate segregation during working hours. Our approach combines three well-known mathematical tools: community detection algorithms, segregation metrics and random walk analysis. Using Santiago (Chile) as our model system, we build a detailed home–work commuting network from a large dataset of mobile phone pings and spatially partition the city into several communities. We then evaluate the probability that two persons at their work location will come from the same community. Finally, a randomization analysis of commuting distances and angles corroborates the strong segregation description for Santiago provided by the sociological literature. While our findings highlights the benefit of developing new approaches to understand dynamic processes in the urban environment, unveiling counterintuitive patterns such as segregation at our workplace also shows a specific example in which the exposure dimension of segregation is successfully studied using the growingly available streams of highly detailed anonymized mobile phone registries.

scholarly journals Predation and Scavenging in the City: A Review of Spatio-Temporal Trends in Research

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 46
Author(s):  
Álvaro Luna ◽  
Pedro Romero-Vidal ◽  
Eneko Arrondo
Keyword(s):  
Urban Areas ◽  
Scientific Literature ◽  
Temporal Trends ◽  
Urban Environments ◽  
Tropical Regions ◽  
Conservation Implications ◽  
Spatio Temporal ◽  
The City ◽  
Trophic Role

Many researchers highlight the role of urban ecology in a rapidly urbanizing world. Despite the ecological and conservation implications relating to carnivores in cities, our general understanding of their potential role in urban food webs lacks synthesis. In this paper, we reviewed the scientific literature on urban carnivores with the aim of identifying major biases in this topic of research. In particular, we explored the number of articles dealing with predation and scavenging, and assessed the geographical distribution, biomes and habitats represented in the scientific literature, together with the richness of species reported and their traits. Our results confirmed that scavenging is largely overlooked compared to predation in urban carnivore research. Moreover, research was biased towards cities located in temperate biomes, while tropical regions were less well-represented, a pattern that was more evident in the case of articles on scavenging. The species reported in both predation and scavenging articles were mainly wild and domestic mammals with high meat-based diets and nocturnal habits, and the majority of the studies were conducted in the interior zone of cities compared to peri-urban areas. Understanding the trophic role of carnivores in urban environments and its ecological consequences will require full recognition of both their predation and scavenging facets, which is especially desirable given the urban sprawl that has been predicted in the coming decades.

Minimetrò in Perugia as leverage for urban regeneration

TERRITORIO ◽  
2020 ◽  
pp. 148-163
Author(s):  
Luca Fondacci
Keyword(s):  
Urban Regeneration ◽  
Urban Environments ◽  
Low Carbon ◽  
Sustainable Mobility ◽  
Field Surveys ◽  
Peripheral Area ◽  
Alternative Means ◽  
Considerable Impact ◽  
The City ◽  
Historical Centre

In the 1970s, the fragile historical centre of the city of Perugia was a key area where the binomial of sustainable mobility and urban regeneration was developed and applied. At the turn of the xxi century, the low carbon automatic people-mover Minimetrò broadened that application from the city's historical centre to the outskirts, promoting the enhancement of several urban environments. This paper is the outcome of an investigation of original sources, field surveys and direct interviews, which addresses the Minimetrò as the backbone of a wide regeneration process which has had a considerable impact on the economic development of a peripheral area of the city which was previously devoid of any clear urban sense. The conclusion proposes some solutions to improve the nature of the Minimetrò as an experimental alternative means of transport.

Using augmented reality for navigation in space. Creating Visual Dictionaries

2020 ◽  
Author(s):  
Aida Khakimova ◽  
Oleg Zolotarev ◽  
Lyudmila Sharapova ◽  
Daler Mirzoev ◽  
Aleksanra Belaya ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Visual Image ◽  
Cultural Codes ◽  
The Subject ◽  
Spatio Temporal ◽  
The City

The image of the city is a spatio-temporal continuum in which everything is interconnected, it exists as a single monolith expressing itself in the general atmosphere. The visual image of the city may contain two planes of meanings: culturally ratified and universally valid, expressed by cultural codes, and also significant only to those who are viewing the image. Therefore, the content of the visual image depends on who the subject of perception is, what he pays attention to and in what situation the process of perception of the image occurs.

scholarly journals Acute Effects on Impact Accelerations Running with Objects in the Hand

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 550
Author(s):  
Roberto Sanchis-Sanchis ◽  
Alberto Encarnación-Martínez ◽  
Jose I. Priego-Quesada ◽  
Inmaculada Aparicio ◽  
Irene Jimenez-Perez ◽  
...  
Keyword(s):  
Mobile Phone ◽  
Step Length ◽  
Stride Frequency ◽  
Acute Effects ◽  
Shock Attenuation ◽  
Acceleration Rate ◽  
Recreational Runners ◽  
Impact Acceleration ◽  
Spatio Temporal ◽  
Extra Weight

Amateur runners usually run carrying implements in their hands (keys, a mobile phone, or a bottle of water). However, there is a lack of literature about the effects of different handloads on impact accelerations. Thus, this study aimed to analyse the effects of carrying different objects in the hand on impact accelerations during running. Nineteen male recreational runners (age 24.3 ± 6.8 years, training volume of 25 ± 7.38 km/week) performed twenty minutes of running on a treadmill at 2.78 m/s with four different conditions: no extra weight, with keys, with a mobile phone, and with a bottle of water. Impact acceleration and spatio-temporal parameters were analysed through a wireless triaxial accelerometry system composed of three accelerometers: two placed in each tibia and one placed on the forehead. A higher tibia acceleration rate in the dominant leg was observed when participants ran holding both a mobile phone (p = 0.027; ES = 0.359) and a bottle of water (p = 0.027; ES = 0.359), compared to no extra weight. No changes were observed in peak acceleration, acceleration magnitude, and shock attenuation in any other conditions. Likewise, neither stride frequency nor step length was modified. Our results suggest that recreational runners should not worry about carrying objects in their hands, like a mobile phone or a bottle of water, in short races because their effect seems minimal.

scholarly journals Facilitating fine-grained intra-urban dengue forecasting by integrating urban environments measured from street-view images

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Kang Liu ◽  
Ling Yin ◽  
Meng Zhang ◽  
Min Kang ◽  
Ai-Ping Deng ◽  
...  
Keyword(s):  
Machine Learning ◽  
High Risk ◽  
Feature Vector ◽  
Urban Environments ◽  
Environmental Feature ◽  
Fine Grained ◽  
Environmental Features ◽  
Street View ◽  
The City ◽  
Dengue Epidemic

Abstract Background Dengue fever (DF) is a mosquito-borne infectious disease that has threatened tropical and subtropical regions in recent decades. An early and targeted warning of a dengue epidemic is important for vector control. Current studies have primarily determined weather conditions to be the main factor for dengue forecasting, thereby neglecting that environmental suitability for mosquito breeding is also an important factor, especially in fine-grained intra-urban settings. Considering that street-view images are promising for depicting physical environments, this study proposes a framework for facilitating fine-grained intra-urban dengue forecasting by integrating the urban environments measured from street-view images. Methods The dengue epidemic that occurred in 167 townships of Guangzhou City, China, between 2015 and 2019 was taken as a study case. First, feature vectors of street-view images acquired inside each township were extracted by a pre-trained convolutional neural network, and then aggregated as an environmental feature vector of the township. Thus, townships with similar physical settings would exhibit similar environmental features. Second, the environmental feature vector is combined with commonly used features (e.g., temperature, rainfall, and past case count) as inputs to machine-learning models for weekly dengue forecasting. Results The performance of machine-learning forecasting models (i.e., MLP and SVM) integrated with and without environmental features were compared. This indicates that models integrating environmental features can identify high-risk urban units across the city more precisely than those using common features alone. In addition, the top 30% of high-risk townships predicted by our proposed methods can capture approximately 50–60% of dengue cases across the city. Conclusions Incorporating local environments measured from street view images is effective in facilitating fine-grained intra-urban dengue forecasting, which is beneficial for conducting spatially precise dengue prevention and control.

Forest path condition monitoring based on crowd-based trajectory data analysis

2020 ◽  
pp. 1-18
Author(s):  
Francisco Arcas-Tunez ◽  
Fernando Terroso-Saenz
Keyword(s):  
Information Acquisition ◽  
Road Network ◽  
Road Networks ◽  
Trajectory Data ◽  
Country Road ◽  
Wide Range ◽  
Sport Activities ◽  
Path Condition ◽  
Spatio Temporal ◽  
The City

The development of Road Information Acquisition Systems (RIASs) based on the Mobile Crowdsensing (MCS) paradigm has been widely studied for the last years. In that sense, most of the existing MCS-based RIASs focus on urban road networks and assume a car-based scenario. However, there exist a scarcity of approaches that pay attention to rural and country road networks. In that sense, forest paths are used for a wide range of recreational and sport activities by many different people and they can be also affected by different problems or obstacles blocking them. As a result, this work introduces SAMARITAN, a framework for rural-road network monitoring based on MCS. SAMARITAN analyzes the spatio-temporal trajectories from cyclists extracted from the fitness application Strava so as to uncover potential obstacles in a target road network. The framework has been evaluated in a real-world network of forest paths in the city of Cieza (Spain) showing quite promising results.

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