This thesis proposes a DIY environmental sensing approach that empowers citizens to reinvigorate people's awareness of, and concern for, pollution. Current air pollution measuring techniques are described, and a new concept of participatory sensing is presented. I argue that technological advances in sensing, computation, storage, and communication now have the power to turn the near-ubiquitous mobile phone into a global mobile sensing device, and commence the participatory paradigm employing amateurs in environmental data collection. To test the thesis, PAIR, a prototype with interchangeable sensor, was developed. It aims to enable people to sense environment on-the-go and provide users with immediate feedback. Such data can make people learn about their environment, make them aware of air pollution causes, and eventually even bring behavioral changes. Consequently, a user survey and interviews identify strengths and weaknesses of the mobile sensing device, and based on the usability requirements, we conclude design recommendations for further development. Finally, we identify the main benefits amateur data collection and participatory sensing represent for urban dwellers, and we evaluate issues and challenges they have yet to overcome.

La dynamique humaine est un sujet essentiel de l'informatique centrée sur l’homme. Elle se concentre sur la compréhension des régularités sous-jacentes, des relations, et des changements dans les comportements humains. En analysant la dynamique humaine, nous pouvons comprendre non seulement des comportements individuels, tels que la présence d’une personne à un endroit précis, mais aussi des comportements collectifs, comme les mouvements sociaux. L’exploration de la dynamique humaine permet ainsi diverses applications, entre autres celles des services géo-dépendants personnalisés dans des scénarios de ville intelligente. Avec l'omniprésence des smartphones équipés de GPS, les réseaux sociaux de géolocalisation ont acquis une popularité croissante au cours des dernières années, ce qui rend les données de comportements des utilisateurs disponibles à grande échelle. Sur les dits réseaux sociaux de géolocalisation, les utilisateurs peuvent partager leurs activités en temps réel avec par l'enregistrement de leur présence à des points d'intérêt (POIs), tels qu’un restaurant. Ces données d'activité contiennent des informations massives sur la dynamique humaine. Dans cette thèse, nous explorons la dynamique humaine basée sur les données massives des réseaux sociaux de géolocalisation. Concrètement, du point de vue individuel, nous étudions la préférence de l'utilisateur quant aux POIs avec des granularités différentes et ses applications, ainsi que la régularité spatio-temporelle des activités des utilisateurs. Du point de vue collectif, nous explorons la forme d'activité collective avec les granularités de pays et ville, ainsi qu’en corrélation avec les cultures globales / Human dynamics is an essential aspect of human centric computing. As a transdisciplinary research field, it focuses on understanding the underlying patterns, relationships, and changes of human behavior. By exploring human dynamics, we can understand not only individual’s behavior, such as a presence at a specific place, but also collective behaviors, such as social movement. Understanding human dynamics can thus enable various applications, such as personalized location based services. However, before the availability of ubiquitous smart devices (e.g., smartphones), it is practically hard to collect large-scale human behavior data. With the ubiquity of GPS-equipped smart phones, location based social media has gained increasing popularity in recent years, making large-scale user activity data become attainable. Via location based social media, users can share their activities as real-time presences at Points of Interests (POIs), such as a restaurant or a bar, within their social circles. Such data brings an unprecedented opportunity to study human dynamics. In this dissertation, based on large-scale location centric social media data, we study human dynamics from both individual and collective perspectives. From individual perspective, we study user preference on POIs with different granularities and its applications in personalized location based services, as well as the spatial-temporal regularity of user activities. From collective perspective, we explore the global scale collective activity patterns with both country and city granularities, and also identify their correlations with diverse human cultures

De nos jours, il y a une demande croissante pour fournir de l'information temps réel à partir de l'environnement, e.g. état infectieux de maladies, force du signal, conditions de circulation, qualité de l'air. La prolifération des dispositifs de capteurs et la mobilité des personnes font de la Mobile Collaborative Sensing (MCS) un moyen efficace de détecter et collecter l'information à un faible coût. Dans MCS, au lieu de déployer des capteurs statiques dans une zone, les personnes disposant d'appareils mobiles jouent le rôle de capteurs mobiles. En général, une application MCS exige que l'appareil de chacun ait la capacité d'effectuer la détection et retourne les résultats à un serveur central, mais également de collaborer avec d'autres dispositifs. Pour que les résultats puissent représenter l'information physique d'une région cible et convenir, quel type de données peut être utilisé et quel type d'information doit être inclus dans les données collectées? Les données spatio-temporelles peuvent être utilisées par des applications pour bien représenter la région cible. Dans des applications différentes, l'information de localisation et de temps sont 2 types d'information communes, et en les utilisant la région cible d'une application est sous surveillance complète du temps et de l'espace. Différentes applications nécessitent de l'information différente pour atteindre des objectifs différents. E.g. dans cette thèse: i- MCS-Locating application: l'information de résistance du signal doit être incluse dans les données détectées par des dispositifs mobiles à partir d'émetteurs de signaux ; ii- MCS-Prédiction application : la relation entre les cas d'infection et les cas infectés doit être incluse dans les données par les dispositifs mobiles provenant des zones de flambée de la maladie ; iii- MCS-Routing application : l'information routière en temps réel provenant de différentes routes de circulation doit être incluse dans les données détectées par des dispositifs embarqués. Avec la détection de l'information physique d'une région cible, et la mise en interaction des dispositifs, 3 thèmes d'optimisation basés sur la détection sont étudiés et 4 travaux de recherche menés: -Mobile Collaboratif Détection Cadre : un cadre mobile de détection collaborative est conçu pour faciliter la coopérativité de la collecte, du partage et de l'analyse des données. Les données sont collectées à partir de sources et de points temporels différents. Pour le déploiement du cadre dans les applications, les défis clés pertinents et les problèmes ouverts sont discutés. -MCS-Locating : l'algorithme LiCS (Locating in Collaborative Sensing based Data Space) est proposé pour atteindre la localisation de la cible. LiCS utilise la puissance du signal reçu dans tous les périphériques sans fil comme empreintes digitales de localisation pour les différents emplacements. De sorte LiCS peut être directement pris en charge par l'infrastructure sans fil standard. Il utilise des données de trace d'appareils mobiles d'individus, et un modèle d'estimation d'emplacement. Il forme le modèle d'estimation de localisation en utilisant les données de trace pour atteindre la localisation de la cible collaborative. Cette collaboration entre périphériques est au niveau des données et est supportée par un modèle. -MCS-Prédiction: un modèle de reconnaissance est conçu pour acquérir dynamiquement la connaissance de structure de la RCN pertinente pendant la propagation de la maladie. Sur ce modèle, un algorithme de prédiction est proposé pour prédire le paramètre R. i.e. le nombre de reproduction qui est utilisé pour quantifier la dynamique de la maladie pendant sa propagation. -MCS-Routing : un algorithme de navigation écologique ‘eRouting’ est conçu en combinant l'information de trafic temps réel et un modèle d'énergie/émission basé sur des facteurs représentatifs. Sur la base de l'infrastructure standard d'un système de trafic intelligent, l'information sur le trafic est collectée / Nowadays, there is an increasing demand to provide real-time information from the environment, e.g., the infection status of infectious diseases, signal strength, traffic conditions, and air quality, to citizens in urban areas for various purposes. The proliferation of sensor-equipped devices and the mobility of people are making Mobile Collaborative Sensing (MCS) an effective way to sense and collect information at a low deployment cost. In MCS, instead of just deploying static sensors in an interested area, people with mobile devices play the role of mobile sensors to sense the information of their surroundings, and the communication network (3G, WiFi, etc.) is used to transfer data for MCS applications. Typically, a MCS application not only requires each participant's mobile device to possess the capability of performing sensing and returning sensed results to a central server, but also requires to collaborate with other mobile and static devices. In order to make sensed results well represent the physical information of a target region, and well be suitable to a certain application, what kind of data can be used for different applications, and what kind of information needs to be included into the collected sensing data? Spatio-temporal data can be used by different applications to well represent the target region. In different applications, location and time information is two kinds of common information, and by using such information, the target region of an application is under comprehensive monitoring from the view of time and space. Different applications require different information to achieve different sensing purposes. E.g. in this thesis: i- MCS-Locating application: signal strength information needs to be included into the sensed data by mobile devices from signal transmitters; ii- MCS-Prediction application: the relationship between infecting and infected cases needs to be included into the sensed data by mobile devices from disease outbreak areas; iii- MCS-Routing application: real-time traffic and road information from different traffic roads, e.g., traffic velocity and road gradient, needs to be included into the sensed data by road-embedded and vehicle-mounted devices. With sensing the physical information of a target region, and making mobile and static devices collaborate with each other in mind, in this thesis three sensing based optimization applications are studied, and following four research works are conducted: - a MCS Framework is designed to facilitate the cooperativity of data collection, sharing, and analysis among different devices. Data is collected from different sources and time points. For deploying the framework into applications, relevant key challenges and open issues are discussed. - MCS-Locating: an algorithm LiCS (Locating in Collaborative Sensing based Data Space) is proposed to achieve target locating. It uses Received Signal Strength that exists in any wireless devices as location fingerprints to differentiate different locations, so it can be directly supported by off-the-shelf wireless infrastructure. LiCS uses trace data from individuals' mobile devices, and a location estimation model. It trains the location estimation model by using the trace data to achieve collaborative target locating. Such collaboration between different devices is data-level, and model-supported. - MCS-Prediction: a recognition model is designed to dynamically acquire the structure knowledge of the relevant RCN during disease spread. On the basis of this model, a prediction algorithm is proposed to predict the parameter R. R is the reproductive number which is used to quantify the disease dynamics during disease spread. - MCS-Routing: an eco-friendly navigation algorithm, eRouting, is designed by combining real-time traffic information and a representative factor based energy/emission model. Based on the off-the-shelf infrastructure of an intelligent traffic system, the traffic information is collected

[pt] Jogos pervasivos móveis são jogos que combinam os mundos real e virtual em um espaço híbrido, permitindo interações não apenas com o mundo do jogo virtualmente criado, mas também com o ambiente físico que envolve os jogadores. A Internet de Coisas Móveis (IoMT) especifica situações em que os dispositivos na Internet das Coisas (IoT) podem ser movidos ou se moverem de forma autônoma, mantendo conectividade remota e acessibilidade de qualquer lugar na Internet. Seguindo o enorme sucesso dos recentes jogos pervasivos móveis e a iminente expansão de IoT, nós fornecemos uma integração para toda a tecnologia envolvida no desenvolvimento de um jogo pervasivo móvel que incorpora dispositivos IoT. Também propomos um jogo móvel pervasivo que avalia os benefícios da união de ambos os campos. Este protótipo de jogo explora maneiras de aumentar a experiência dos jogadores através de mecânicas pervasivas, aproveitando a motivação dos jogadores para realizar tarefas de sensoriamento. O jogo também incorpora aplicações sérias na jogabilidade, tais como a localização de instalações e serviços. / [en] Mobile pervasive games are a game genre that combines the real and virtual worlds in a hybrid space, allowing interactions with not only the virtually created game world, but also with the physical environment that surrounds the players. The Internet of Mobile Things (IoMT) specifies situations in which devices on the Internet of Things (IoT) can be moved or move autonomously, while maintaining remote connectivity and accessibility from anywhere on the internet. Following the huge success of recent mobile pervasive games and the coming IoT boom, we provide an integration for all the technology involved in the development of a mobile pervasive game that incorporates IoT devices. We also propose a mobile pervasive game that evaluates the benefits of the union of both fields. This game prototype explores ways of increasing the experience of players through pervasive mechanics while taking advantage of the player s motivation to perform sensing tasks. It also incorporates serious applications into the gameplay, such as the localization of facilities and services.

Participatory sensing systems need to gather information from a largenumber of participants. However, the openness of the system is a doubleedgedsword: by allowing practically any user to join, the system can beabused by an attacker who introduces a large number of virtual devices.This work proposes a hardened registration process for participatory sensingto raise the bar: registrations are screened through a number of defensivemeasures, towards rejecting spurious registrations that do not correspondto actual devices. This deprives an adversary from a relatively easytake-over and, at the same time, allows a flexible and open registrationprocess. The defensive measures are incorporated in the participatorysensing application. / Deltagande avkännings system behöver samlas från ett stort antal aktörer.Systems öppenhet är dock en dubbelsidigt värd: Genom att låta alla praktiskaanvändare deltagit, kan system utnyttja en av angripare som introducera ett stortantal virtuella enheter. I det här arbetet föreslå en härda registreringsprocess fördeltagare att identifiera höjning av ribban: registrering screenas genom ett antaldefensiva åtgärders, för att avvisa falska registreringar som inte motsvara aktuellaenheter. Detta berövar en motståndare från en relativt lätt övertagande och gersamtidigt en flexibel och öppen registreringsprocess. De defensiva åtgärdernainförlivas i deltagande avkännings applikation.

Participatory Sensing (PS) is a common mode of data collection where valuable data is gathered from many contributors, each providing data from the user’s or the device’s surroundings via a mobile device, such as a smartphone. This has the advantage of cost-efficiency and wide-scale data collection. One of the application areas for PS is the collection of traffic data. The cost of collecting roving sensor data, such as vehicle probe data, is significantly lower than that of traditional stationary sensors such as radar and inductive loops. The collected data could pave the way for providing accurate and high-resolution traffic information that is important to transportation planning. The problem with PS is that it is open, and anyone can register and participate in a sensing task. A malicious user is likely to submit false data without performing the sensing task for personal advantage or, even worse, to attack on a large scale with clear intentions. For example, in real-time traffic monitoring, attackers may report false alerts of traffic jams to divert traffic on the road ahead or directly interfere with the system’s observation and judgment of road conditions, triggering large-scale traffic guidance errors. An efficient method of assessing the trustworthiness of data is therefore required. The trustworthiness problem can be approximated as the problem of anomaly detection in time-series data. Traditional predictive model-based anomaly detection models include univariate models for univariate time series such as Auto Regressive Integrated Moving Average (ARIMA), hypothesis testing, and wavelet analysis, and recurrent neural networks (RNNs) for multiple time series such as Gated Recurrent Unit (GRU) and Long short-term memory (LSTM). When talking about traffic scenarios, some prediction models that consider both spatial and temporal dependencies are likely to perform better than those that only consider temporal dependencies, such as Diffusion Convolutional Recurrent Neural Network (DCRNN) and Spatial-Temporal Attention Wavenet (STAWnet). In this project, we built a detailed traffic condition participatory sensing scenario as well as an adversary model. The attacker’s intent is refined into four attack scenarios, namely faking congestion, prolonging congestion, and masking congestion from the beginning or midway through. On the basis, we established a mechanism for assessing the trustworthiness of the data using three traffic prediction models. One model is the time-dependent deep neural network prediction model DCRNN, and the other two are a simplified version of the model DCRNN-NoCov, which ignores spatial dependencies, and ARIMA. The ultimate goal of this evaluation mechanism is to give a list of attackers and to perform data filtering. We use the success rate of distinguishing users as benign or attackers as a metric to evaluate the system’s performance. In all four attack scenarios mentioned above, the system achieves a success rate of more than 80%, obtaining satisfactory results. We also discuss the more desirable attack strategies from the attacker’s point of view. / Participatory Sensing (PS) är ett vanligt sätt att samla in data där värdefulla data samlas in från många bidragsgivare, som alla tillhandahåller data från användarens eller enhetens omgivning via en mobil enhet, t.ex. en smartphone. Detta har fördelen av kostnadseffektivitet och omfattande datainsamling. Ett av tillämpningsområdena för PS är insamling av trafikdata. Kostnaden för att samla in data från mobila sensorer, t.ex. data från fordonssonderingar, är betydligt lägre än kostnaden för traditionella stationära sensorer, t.ex. radar och induktiva slingor. De insamlade uppgifterna skulle kunna bana väg för att tillhandahålla exakt och högupplöst trafikinformation som är viktig för transportplaneringen. Problemet med deltagande avkänning är att den är öppen och att vem som helst kan registrera sig och delta i en avkänningsuppgift. En illasinnad användare kommer sannolikt att lämna in falska uppgifter utan att utföra avkänningsuppgiften för personlig vinning eller, ännu värre, för att angripa en stor skala med tydliga avsikter. Vid trafikövervakning i realtid kan t.ex. angripare rapportera falska varningar om trafikstockningar för att avleda trafiken på vägen framåt eller direkt störa systemets observation och bedömning av vägförhållanden, vilket kan utlösa storskaliga fel i trafikstyrningen. Det finns därför ett akut behov av en effektiv metod för att bedöma uppgifternas tillförlitlighet. Problemet med trovärdighet kan approximeras som problemet med upptäckt av anomalier i tidsserier. Traditionella modeller för anomalidetektion som bygger på prediktiva modeller omfattar univariata modeller för univariata tidsserier, t.ex. ARIMA (Autoregressive Integrated Moving Average), hypotesprövning och waveletanalys, och återkommande neurala nätverk (RNN) för flera tidsserier, t.ex. GRU (Gated Recurrent Unit) och LSTM (Long short-term memory). När man talar om trafikscenarier kommer vissa prognosmodeller som tar hänsyn till både rumsliga och tidsmässiga beroenden sannolikt att prestera bättre än de som endast tar hänsyn till tidsmässiga beroenden, till exempel Diffusion Convolutional Recurrent Neural Network (DCRNN) och Spatial-Temporal Attention Wavenet (STAWnet). I det här projektet byggde vi upp ett detaljerat scenario för deltagande av trafikförhållanden och en motståndarmodell. Angriparens avsikt är raffinerad i fyra angreppsscenarier, nämligen att fejka trafikstockning, förlänga trafikstockning och maskera trafikstockning från början eller halvvägs in i processen. På grundval av detta har vi inrättat en mekanism för att bedöma uppgifternas tillförlitlighet med hjälp av tre typiska trafikprognosmodeller. Den ena modellen är den tidsberoende djupa neurala nätverksförutsägelsemodellen DCRNN, och de andra två är en förenklad version av modellen DCRNN-NoCov, som ignorerar rumsliga beroenden, och ARIMA. Det slutliga målet med denna utvärderingsmekanism är att ge en lista över angripare och att utföra datafiltrering. Vi använder framgångsfrekvensen när det gäller att särskilja användare som godartade eller angripare som ett mått för att utvärdera systemets prestanda. I alla fyra olika attackscenarier som nämns ovan uppnår systemet en framgångsfrekvens på mer än 80%, vilket ger tillfredsställande resultat. Vi diskuterar också de mer önskvärda angreppsstrategierna ur angriparens synvinkel.