Application of GIS to assess the accessibility of urban streets in Baghdad city

Accessibility has an important impact on shaping human activity patterns on all of the spatial scales. This study presented an evaluation of accessibility levels with private to commercial centers for three selected routes in Baghdad city. The study involved more than 45 days transport survey for private vehicles in Baghdad city using Global Positioning System (GPS) probe for recording indicators of traffic performance. Gravity model was used to measure accessibility index as an implementation of GIS-based model by using link geography and the spatial boundary of analysis in order to build route networks at three routes in Baghdad City, Bayaa intersection - Bab Al-Muatham intersection (Route 1), Bayaa intersection - Bab Al-Muatham intersection (Route 2) and 14 Ramadan Street - Bab Al-Muatham intersection (Route 3). It was found that Route 1 has the high accessibility index with 0.67 in compare with Route 2 and 3 (0.58 and 0.59), respectively. The reason that Route 1 had the highest accessibility index due to the high access point and low traffic volume as compared with the other two routes.

Modeling intra-urban human activity patterns using crowdsourcing GPS and Geosocial Media Data

The way people live in cities forms human activity patterns, which affects how urban systems work. Therefore, it is essential to understand human activity patterns, where precise prediction of human movements and mechanistic modelling of human activity patterns are the two keys. Most of existing work on prediction of human movements cannot deal with activity changes, leading to a negative impact on the predictive accuracy. Furthermore, the majority of current work on modelling human activity patterns are mainly researched from spatiotemporal perspectives, but the motivation behind is usually being neglected, which is crucial to understanding activity changes. The objective of this study is to develop models and methods to better understand human activity patterns using crowdsourcing and geosocial media data. Thus, in this thesis, a method is first developed to detect activity changes, based on which a Markov chain-based model is developed to predict human movements. Then, semantics is introduced to uncover the motivation associated with the corresponding spatiotemporal patterns, which can infer what people do and discuss in a location at a specific time. Finally, human activity patterns are modelled from both spatiotemporal and semantic perspectives. A 6-year GPS dataset of human movement in Beijing, China was used to evaluate the proposed predictive model. The results show that the predictive model can yield accurate prediction of the movement for those users who have significant activity changes (with R2 improved from 0.295 to 0.762). A whole-year geo-tagged tweets posted within Toronto, Canada was acquired to analyze human activity patterns. A network model was finally created by the proposed approach to represent human activity patterns. The experimental findings demonstrate that most of the individuals (61%) have a regular activity pattern, while only a small number of people (10%) have a different activity pattern from the mass. With the inclusion of semantic information together with the spatiotemporal data as well as detecting the activity changes, such an approach can enhance the capability of human mobility and activity modelling, and thus pave the way for a more mechanistic understanding of how urban systems are being shaped, as well as how their sub-systems/components interact.

Modeling intra-urban human activity patterns using crowdsourcing GPS and Geosocial Media Data

The way people live in cities forms human activity patterns, which affects how urban systems work. Therefore, it is essential to understand human activity patterns, where precise prediction of human movements and mechanistic modelling of human activity patterns are the two keys. Most of existing work on prediction of human movements cannot deal with activity changes, leading to a negative impact on the predictive accuracy. Furthermore, the majority of current work on modelling human activity patterns are mainly researched from spatiotemporal perspectives, but the motivation behind is usually being neglected, which is crucial to understanding activity changes. The objective of this study is to develop models and methods to better understand human activity patterns using crowdsourcing and geosocial media data. Thus, in this thesis, a method is first developed to detect activity changes, based on which a Markov chain-based model is developed to predict human movements. Then, semantics is introduced to uncover the motivation associated with the corresponding spatiotemporal patterns, which can infer what people do and discuss in a location at a specific time. Finally, human activity patterns are modelled from both spatiotemporal and semantic perspectives. A 6-year GPS dataset of human movement in Beijing, China was used to evaluate the proposed predictive model. The results show that the predictive model can yield accurate prediction of the movement for those users who have significant activity changes (with R2 improved from 0.295 to 0.762). A whole-year geo-tagged tweets posted within Toronto, Canada was acquired to analyze human activity patterns. A network model was finally created by the proposed approach to represent human activity patterns. The experimental findings demonstrate that most of the individuals (61%) have a regular activity pattern, while only a small number of people (10%) have a different activity pattern from the mass. With the inclusion of semantic information together with the spatiotemporal data as well as detecting the activity changes, such an approach can enhance the capability of human mobility and activity modelling, and thus pave the way for a more mechanistic understanding of how urban systems are being shaped, as well as how their sub-systems/components interact.

The rhythms of the night: increase in online night activity and emotional resilience during the spring 2020 Covid-19 lockdown

Context The lockdown orders established in multiple countries in response to the Covid-19 pandemic are arguably one of the most widespread and deepest shock experienced by societies in recent years. Studying their impact trough the lens of social media offers an unprecedented opportunity to understand the susceptibility and the resilience of human activity patterns to large-scale exogenous shocks. Firstly, we investigate the changes that this upheaval has caused in online activity in terms of time spent online, themes and emotion shared on the platforms, and rhythms of content consumption. Secondly, we examine the resilience of certain platform characteristics, such as the daily rhythms of emotion expression. Data Two independent datasets about the French cyberspace: a fine-grained temporal record of almost 100 thousand YouTube videos and a collection of 8 million Tweets between February 17 and April 14, 2020. Findings In both datasets we observe a reshaping of the circadian rhythms with an increase of night activity during the lockdown. The analysis of the videos and tweets published during lockdown shows a general decrease in emotional contents and a shift from themes like work and money to themes like death and safety. However, the daily patterns of emotions remain mostly unchanged, thereby suggesting that emotional cycles are resilient to exogenous shocks.