Pokémon Go, a location-based game that uses augmented reality techniques, received unprecedented media coverage due to claims that it allowed for greater access to public spaces, increasing the number of people out on the streets, and generally improving health, social, and security indices. However, the true impact of Pokémon Go on people's mobility patterns in a city is still largely unknown. In this paper, we perform a natural experiment using data from mobile phone networks to evaluate the effect of Pokémon Go on the pulse of a big city: Santiago, capital of Chile. We found significant effects of the game on the floating population of Santiago compared to movement prior to the game's release in August 2016: in the following week, up to 13.8% more people spent time outside at certain times of the day, even if they do not seem to go out of their usual way. These effects were found by performing regressions using count models over the states of the cellphone network during each day under study. The models used controlled for land use, daily patterns, and points of interest in the city.Our results indicate that, on business days, there are more people on the street at commuting times, meaning that people did not change their daily routines but slightly adapted them to play the game. Conversely, on Saturday and Sunday night, people indeed went out to play, but favored places close to where they live.Even if the statistical effects of the game do not reflect the massive change in mobility behavior portrayed by the media, at least in terms of expanse, they do show how 'the street' may become a new place of leisure. This change should have an impact on long-term infrastructure investment by city officials, and on the drafting of public policies aimed at stimulating pedestrian traffic.

In Latin America, shopping malls seem to offer an open, safe and democratic version of the public space. However, it is often difficult to quantitatively measure whether they indeed foster, hinder, or are neutral with respect to social inclusion. In this work, we investigate if, and by how much, people from different social classes are attracted by the same malls. Using a dataset of mobile phone network records from 387,152 devices identified as customers of 16 malls in Santiago de Chile, we performed several analyses to study whether malls with higher social mixing attract more people. Our pipeline, which starts with the socioeconomic characterization of mall visitors, includes the estimation of social mixing and diversity of malls, the application of the gravity model of mobility, and the definition of a co-visitation model. Results showed that people tend to choose a profile of malls more in line with their own socioeconomic status and the distance from their home to the mall, and that higher mixing does positively contribute to the process of choosing a mall. We conclude that (a) there is social mixing in malls, and (b) that social mixing is a factor at the time of choosing which mall to go to. Thus, the potential for social mixing in malls could be capitalized by designing public policies regarding transportation and mobility to make some malls strong social inclusion hubs.

Cities are growing at a fast rate, and transportation networks need to adapt accordingly. To design, plan, and manage transportation networks, domain experts need data that reflect how people move from one place to another, at what times, for what purpose, and in what mode(s) of transportation. However, traditional data collection methods are not cost-effective or timely. For instance, travel surveys are very expensive, collected every ten years, a period of time that does not cope with quick city changes, and using a relatively small sample of people. In this paper, we propose an algorithmic pipeline to infer the distribution of mode of transportation usage in a city, using mobile phone network data. Our pipeline is based on a Topic-Supervised Non-Negative Matrix Factorization model, using a Weak-Labeling strategy on user trajectories with data obtained from open datasets, such as GTFS and OpenStreetMap. As a case study, we show results for the city of Santiago, Chile, which has a sophisticated intermodal public transportation system. Importantly, our pipeline delivers coherent results that are explainable, with interpretable parameters at each step. Finally, we discuss the potential applications and implications of such a system in transportation and urban planning.

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In this paper we propose three compact data structures to answer queries on temporal graphs. We define a temporal graph as a graph whose edges appear or disappear along time. Possible queries are related to adjacency along time, for example, to get the neighbors of a node at a given time point or interval.A naive representation consists of a time-ordered sequence of graphs, each of them valid at a particular time instant. The main issue of this representation is the unnecessary use of space if many nodes and their connections remain unchanged during a long period of time. The work in this paper proposes to store only what changes at each time instant.The ttk 2 -tree is conceptually a dynamic k 2 -tree [1] in which each leaf and internal node contains a change list of time instants when its bit value has changed. All the change lists are stored consecutively in a dynamic sequence. During query processing, the change lists are used to expand only valid regions in the dynamic k 2 -tree. It supports updates of the current or past states of the graph.The ltg-index is a set of snapshots and logs of changes between consecutive snapshots. The structure keeps a log for each node, storing the edge and the time where a change has been produced. To retrieve direct neighbors of a node, the previous snapshot is queried, and then the log is traversed adding or removing edges to the result.The differential k 2 -tree stores snapshots of some time instants in k 2 -trees. For the other time instants, a k 2 -tree is also built, but these are differential (they store the edges that differ from the last snapshot). To perform a query it accesses the k 2 -tree of the given time and the previous full snapshot. The edges that appear in exactly one of these two k 2 -trees will be the final results.We test our proposals using synthetic and real datasets. Our results show that the ltg-index obtains the smallest space in general. We also measure times for direct and reverse neighbor queries in a time instant or a time interval. For all these queries, the times of our best proposal range from tens of μs to several ms, depending on the size of the dataset and the number of results returned. The ltg-index is the fastest for direct queries (almost as fast as accessing a snapshot), but it is 5-20 times slower in reverse queries. The differential k 2 -tree is very fast in time instant queries, but slower in time interval queries. The ttk 2 -tree obtains similar times for direct and reverse queries and different time intervals, being the fastest in some reverse interval queries. It has also the advantage of being dynamic.

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People often base their mobility decisions on subjective aspects of travel experience, such as time perception, space usage, and safety. It is well recognized that different groups within a population will react differently to the same trip, however, current data collection methods might not consider the multi dimensional aspects of travel perception, which could lead to overlooking the needs of large population groups. In this paper, we propose to measure several aspects of the travel experience from the social media platform Twitter, with a focus on differences with respect to gender. We analyzed more than 400,000 tweets from 100,000 users about transportation from Santiago, Chile. Our main findings show that both genders express themselves differently, as women write about their emotions regarding travel (both, positive and negative feelings), that men express themselves using slang, making it difficult to interpret emotion. The strongest difference is related to harassment, not only on transportation, but also on the public space. Since these aspects are usually omitted from travel surveys, our work provides evidence on how Twitter allows the measurement of aspects of the transportation system in a city that have been studied in qualitative terms, complementing surveys with emotional and safety aspects that are as relevant as those traditionally measured.