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—Participatory sensing systems (PSSs) have the potential to become fundamental tools to support the study, in large scale, of urban social behavior and city dynamics. To that end, this work characterizes the photo sharing system Instagram, considered one of the currently most popular PSS on the Internet. Based on a dataset of approximately 2.3 million(More)
Food and drink are two of the most basic needs of human beings. However, as society evolved, food and drink became also a strong cultural aspect, being able to describe strong differences among people. Traditional methods used to analyze cross-cultural differences are mainly based on surveys and, for this reason, they are very difficult to represent a(More)
—With the recent advances in technology, we have the opportunity to study the city dynamics at a large scale. A fundamental step is to be able to sense extensive areas. Participatory sensor networks have the potential to become a very fundamental tool to study social behavior at a large scale. Currently, there are some location sharing services, such as(More)
A fundamental step to achieve the Ubiquitous Computing vision is to sense the environment. The research in Wireless Sensor Networks has provided several tools, techniques and algorithms to solve the problem of sensing in limited size areas, such as forests or volcanoes. However, sensing large scale areas, such as large metropolises, countries, or even the(More)
We here investigate the potential of participatory sensor networks derived from location sharing systems, such as Foursquare, to understand the human dynamics of cities. We propose the City Image visualization technique, which builds a transition graph mapping people's movements between location categories, and demonstrate its use to identify similarities(More)
—Cities are not identical and evolve over time, and sensing in large scale can be used to capture these differences. Research in Wireless Sensor Networks has provided several tools, techniques and algorithms to solve the problem of sensing in restricted scenarios (e.g., factory). However, sensing large scale areas, such as big cities, brings many challenges(More)
—The ubiquitous availability of computing technology such as smartphones, tablets and other easily portable devices, and the worldwide adoption of social networking sites make it increasingly possible for one to be connected and continuously contribute to this massively distributed information publishing 5 process. In this scenario, people act as social(More)
Traffic jam is a contemporary society problem in urban areas. There are specific sources of information about traffic conditions in the Web, such as Bing Maps. This system presents real-time information about the traffic conditions (e.g., free or congested). Recently, participatory sensing systems, such as Foursquare and Instagram, are becoming very(More)
Food and drink are two of the most basic needs of human beings. However, as society evolved, food and drink became also a strong cultural aspect, being able to describe strong differences among people. Traditional methods used to analyze cross-cultural differences are mainly based on surveys and, for this reason, they are very difficult to represent a(More)