Inferring Activities from Social Media Data

Social media produce an unprecedented amount of information that can be extracted and used in transportation research, with one of the most promising areas being the inference of individuals’ activities. Whereas most studies in the literature focus on the direct use of social media data, this study presents an efficient framework that follows a user-centric approach for the inference of users’ activities from social media data. The framework was applied to data from Twitter, combined with inferred data from Foursquare that contains information about the type of location visited. The users’ data were then classified with a density-based spatial classification algorithm that allows for the definition of commonly visited locations, and the individual-based data were augmented with the known activity definition from Foursquare. On the basis of the known activities and the Twitter text, a set of classification algorithms was applied for the inference of activities. The results are discussed according to the types of activities recognized and the classification performance. The classification results allow for a wide application of the framework in the exploration of the activity space of individuals

Advances in crowd analysis for urban applications through urban event detection

The recent expansion of pervasive computing technology has contributed with novel means to pursue human activities in urban space. The urban dynamics unveiled by these means generate an enormous amount of data. These data are mainly endowed by portable and radio-frequency devices, transportation systems, video surveillance, satellites, unmanned aerial vehicles, and social networking services. This has opened a new avenue of opportunities, to understand and predict urban dynamics in detail, and plan various real-time services and applications in response to that. Over the last decade, certain aspects of the crowd, e.g., mobility, sentimental, size estimation and behavioral, have been analyzed in detail and the outcomes have been reported. This paper mainly conducted an extensive survey on various data sources used for different urban applications, the state-of-the-art on urban data generation techniques and associated processing methods in order to demonstrate their merits and capabilities. Then, available open-access crowd data sets for urban event detection are provided along with relevant application programming interfaces. In addition, an outlook on a support system for urban application is provided which fuses data from all the available pervasive technology sources and finally, some open challenges and promising research directions are outlined

Determinants of public transport use in Perth, Western Australia

This study examines the primary determinants explaining spatial and temporal variations in public transportation use in Perth using 2009 SmartRider data. The developed robust predictive model includes land use, urban form, socio-economic characteristics and public transport availability. Land-use development integrated with sustainable transportation systems, more frequent and densely distributed feeder bus service to train stations, density of low-income resident and university student populations are highlighted as important for policy making encouraging increased public transport use

Coping has limits: 'Mixed Presenters' emergency department presentations for self-harm and other reasons

Suicide is largely preventable, in part through effective emergency department (ED) care of people at risk of self-harm. Ample research on people presenting to ED for self-harm (including suicidal ideation, deliberate self-harm, and suicide attempts) exists, yet less is known about those who present also for other reasons within a short time of their self-harm visit. This information is important because ‘other’ ED presentations might indicate heightened future self-harm risk; ED patients presenting for other reasons might also be at risk of (oftentimes undetected) self-harm; and ED staff attitude, frequently negative for patients who present for self-harm, might represent a unique mind-set toward patients with these mixed or two-type presentations. This research investigated ‘Mixed Presenters’, people who presented to one ED at least twice within 28 days, once for self-harm and once for another reason. It sought to answer the following questions: Who are Mixed Presenters? What is the future serious self-harm risk of Mixed Presenters compared to Self-harm Only Presenters? What characterises the ED management of Mixed Presenters? This mixed method study used ED data from another study (MISP), which facilitated the identification of Mixed Presenters. The qualitative part involved semi-structured interviews with 27 Mixed Presenters from three DHBs. For the quantitative part, data from 1921 patients, 1554 (80.4%) Mixed Presenters and 377 (19.6%) Self-harm Only Presenters, from eight DHBs were linked to admission and mortality datasets and were analysed using survival analysis to compare serious self-harm risk between the groups. The findings of the qualitative and quantitative studies were reported separately and then triangulated. Mixed Presenters reported difficult life circumstances consisting of interwoven physical, mental health, and social struggles for which they received little help. The quantitative results showed Mixed Presenters to have a 60% reduced risk of future serious self-harm compared to Self-harm Only Presenters. Yet, interviews with Mixed Presenters revealed that the vast majority had a history of prior self-harm, were easily triggered to self-harm as a consequence of their life stressors, and on discharge from ED, nearly half were still at risk of self-harm. Mixed Presenters reluctantly sought ED care but acknowledged it provided safety. Many interviewees also disliked the ‘processing plant’ style in ED, where the focus was on risk assessment instead of their needs as people, and where some encountered judgemental staff. These findings show that it is important for ED staff to identify Mixed Presenters. Hence, integrated care is required, which is patient-centred and identifies and addresses physical and self-harm needs simultaneously, and thus ultimately lessens the need for Mixed Presenters to return to ED. Opportunities for disclosure of self-harm could be increased by introducing routine self-harm screening of ED presentations related to substance misuse, degenerative physical health conditions, chronic pain, mental health issues, and trauma. Future research needs to explore Mixed Presenters’ ‘other’ visits, examine their long-term risk of self-harm, and explore support people’s and ED staff’s views on Mixed Presenters so their ED care can be enhanced. Whilst two ED presentations for self-harm incurred a significantly higher risk for future serious self-harm compared to mixed presentations, Mixed Presenters’ often complex life circumstances, frequently linked to chronic and or/high self-harm risk, make targeted ED support for these patients nevertheless imperative