Dynamic Deployment of Sensing Experiments in the Wild Using Smartphones

Part 1: Full Research PapersInternational audienceWhile scientific communities extensively exploit simulations to validate their theories, the relevance of their results strongly depends on the realism of the dataset they use as an input. This statement is particularly true when considering human activity traces, which tend to be highly unpredictable. In this paper, we therefore introduce APISENSE, a distributed crowdsensing platform for collecting realistic activity traces. In particular, APISENSE provides to scientists a participative platform to help them to easily deploy their sensing experiments in the wild. Beyond the scientific contributions of this platform, the technical originality of APISENSE lies in its Cloud orientation and the dynamic deployment of scripts within the mobile devices of the participants.We validate this platform by reporting on various crowdsensing experiments we deployed using Android smartphones and comparing our solution to existing crowdsensing platforms

Evaluating Sensor Data in the Context of Mobile Crowdsensing

With the recent rise of the Internet of Things the prevalence of mobile sensors in our daily life experienced a huge surge. Mobile crowdsensing (MCS) is a new emerging paradigm that realizes the utility and ubiquity of smartphones and more precisely their incorporated smart sensors. By using the mobile phones and data of ordinary citizens, many problems have to be solved when designing an MCS-application. What data is needed in order to obtain the wanted results? Should the calculations be executed locally or on a server? How can the quality of data be improved? How can the data best be evaluated? These problems are addressed by the design of a streamlined approach of how to create an MCS-application while having all these problems in mind. In order to design this approach, an exhaustive literature research on existing MCS-applications was done and to validate this approach a new application was designed with its help. The procedure of designing and implementing this application went smoothly and thus shows the applicability of the approach

Quality of Information in Mobile Crowdsensing: Survey and Research Challenges

Smartphones have become the most pervasive devices in people's lives, and are clearly transforming the way we live and perceive technology. Today's smartphones benefit from almost ubiquitous Internet connectivity and come equipped with a plethora of inexpensive yet powerful embedded sensors, such as accelerometer, gyroscope, microphone, and camera. This unique combination has enabled revolutionary applications based on the mobile crowdsensing paradigm, such as real-time road traffic monitoring, air and noise pollution, crime control, and wildlife monitoring, just to name a few. Differently from prior sensing paradigms, humans are now the primary actors of the sensing process, since they become fundamental in retrieving reliable and up-to-date information about the event being monitored. As humans may behave unreliably or maliciously, assessing and guaranteeing Quality of Information (QoI) becomes more important than ever. In this paper, we provide a new framework for defining and enforcing the QoI in mobile crowdsensing, and analyze in depth the current state-of-the-art on the topic. We also outline novel research challenges, along with possible directions of future work.Comment: To appear in ACM Transactions on Sensor Networks (TOSN

SenCity Workshop: Sensing Festivals as Cities

ACM allows authors to post the accepted, peer-reviewed version of their paper on the institutional repository. The published version is available at .In order to sense the mood of a city, we propose first looking at festivals. In festivals such as Glastonbury or Burning Man we see temporary cities where the inhabitants are engaged afresh with their environment and each other. Our position is that not only are there direct equivalences between larger festivals and cities, but in festivals the phenomena are often exaggerated, and the driving impulses often exploratory. These characteristics well suit research into sensing and intervening in the urban experience. To this end, we have built a corpus of sensor and social media data around a 18,000 attendee music festival and are developing ways of analysing and communicating it

From Personalized Medicine to Population Health: A Survey of mHealth Sensing Techniques

Mobile Sensing Apps have been widely used as a practical approach to collect behavioral and health-related information from individuals and provide timely intervention to promote health and well-beings, such as mental health and chronic cares. As the objectives of mobile sensing could be either \emph{(a) personalized medicine for individuals} or \emph{(b) public health for populations}, in this work we review the design of these mobile sensing apps, and propose to categorize the design of these apps/systems in two paradigms -- \emph{(i) Personal Sensing} and \emph{(ii) Crowd Sensing} paradigms. While both sensing paradigms might incorporate with common ubiquitous sensing technologies, such as wearable sensors, mobility monitoring, mobile data offloading, and/or cloud-based data analytics to collect and process sensing data from individuals, we present a novel taxonomy system with two major components that can specify and classify apps/systems from aspects of the life-cycle of mHealth Sensing: \emph{(1) Sensing Task Creation \& Participation}, \emph{(2) Health Surveillance \& Data Collection}, and \emph{(3) Data Analysis \& Knowledge Discovery}. With respect to different goals of the two paradigms, this work systematically reviews this field, and summarizes the design of typical apps/systems in the view of the configurations and interactions between these two components. In addition to summarization, the proposed taxonomy system also helps figure out the potential directions of mobile sensing for health from both personalized medicines and population health perspectives.Comment: Submitted to a journal for revie

Evidence-Aware Mobile Computational Offloading

Non Peer reviewe

Analysis of the Impact of Performance on Apps Retention

The non-stopping expansion of mobile technologies has produced the swift increase of smartphones with higher computational power, and sophisticated sensing and communication capabilities have provided the foundations to develop apps on the move with PC-like functionality. Indeed, nowadays apps are almost everywhere, and their number has increased exponentially with Apple AppStore, Google Play and other mobile app marketplaces offering millions of apps to users. In this scenario, it is common to find several apps providing similar functionalities to users. However, only a fraction of these applications has a long-term survival rate in app stores. Retention is a metric widely used to quantify the lifespan of mobile apps. Higher app retention corresponds to higher adoption and level of engagement. While existing scientific studies have analysed mobile users' behaviour and support the existence of factors that influence apps retention, the quantification about how do these factors affect long-term usage is still missing. In this thesis, we contribute to these studies quantifying and modelling one of the critical factors that affect app retention: performance. We deepen the analysis of performance based on two key-related variables: network connectivity and battery consumption. The analysis is performed by combining two large-scale crowdsensed datasets. The first includes measurements about network quality and the second about app usage and energy consumption. Our results show the benefits of data fusion to introduce richer contexts impossible of being discovered when analysing data sources individually. We also demonstrate that, indeed, high variations of these variables together and individually affect the likelihood of long-term app usage. But also, that retention is regulated by what users consider reasonable standards of performance, meaning that the improvement of latency and energy consumption does not guarantee higher retention. To provide further insights, we develop a model to predict retention using performance-related variables. Its accuracy in the results allows generalising the effect of performance in long-term usage across categories, locations and moderating variables

Crowdsensed Mobile Data Analytics

Mobile devices, especially smartphones, are nowadays an essential part of everyday life. They are used worldwide and across all the demographic groups - they can be utilized for multiple functionalities, including but not limited to communications, game playing, social interactions, maps and navigation, leisure, work, and education. With a large on-device sensor base, mobile devices provide a rich source of data. Understanding how these devices are used help us also to increase the knowledge of people's everyday habits, needs, and rituals. Data collection and analysis can thus be utilized in different recommendation and feedback systems that further increase usage experience of the smart devices. Crowdsensed computing describes a paradigm where multiple autonomous devices are used together to collect large-scale data. In the case of smartphones, this kind of data can include running and installed applications, different system settings, such as network connection and screen brightness, and various subsystem variables, such as CPU and memory usage. In addition to the autonomous data collection, user questionnaires can be used to provide a wider view to the user community. To understand smartphone usage as a whole, different procedures are needed for cleaning missing and misleading values and preprocessing information from various sets of variables. Analyzing large-scale data sets - rising in size to terabytes - requires understanding of different Big Data management tools, distributed computing environments, and efficient algorithms to perform suitable data analysis and machine learning tasks. Together, these procedures and methodologies aim to provide actionable feedback, such as recommendations and visualizations, for the benefit of smartphone users, researchers, and application development. This thesis provides an approach to a large-scale crowdsensed mobile analytics. First, this thesis describes procedures for cleaning and preprocessing mobile data collected from real-life conditions, such as current system settings and running applications. It shows how interdependencies between different data items are important to consider when analyzing the smartphone system state as a whole. Second, this thesis provides suitable distributed machine learning and statistical analysis methods for analyzing large-scale mobile data. The algorithms, such as the decision tree-based classification and recommendation system, and information analysis methods presented in this thesis, are implemented in the distributed cloud-computing environment Apache Spark. Third, this thesis provides approaches to generate actionable feedback, such as energy consumption and application recommendations, which can be utilized in the mobile devices themselves or when understanding large crowds of smartphone users. The application areas especially covered in this thesis are smartphone energy consumption analysis in the case of system settings and subsystem variables, trend-based application recommendation system, and analysis of demographic, geographic, and cultural factors in smartphone usage.Erilaiset älylaitteet, erityisesti älypuhelimet, ovat muodostuneet oleelliseksi osaksi arkipäivän elektroniikan käyttöä. Älypuhelinten käyttö ei rajoitu perinteisiin kommunikaatiotoimintoihin, vaan niillä on voitu korvata monia muita laitteita ja palveluita, kuten pelit, kartat, sosiaalinen media, ja monet Internetin kautta saavutettavat palvelut. Koska laitteita on saatavilla monissa eri hintaluokissa, ne ovat pääsääntöisesti lähes kaikkien saatavilla, myös maailmanlaajuisesti. Aina mukana kannettavan älypuhelimen käyttö tuottaa runsaasti henkilökohtaista tietoa, mikä tarjoaa mahdollisuuden analysoida käyttäjien päivittäistä elämää. Henkilökohtaisia suosituksia hyödyntäen käyttäjille voidaan tarjota tietoa, joka auttaa parantamaan käyttäjäkokemusta ja laajentamaan älylaitteen käyttömahdollisuuksia. Joukkoistava havainnointi tarkoittaa tiedonkeräysmenetelmää, jossa useat erilliset laitteet osallistuvat automaattisesti suuremman datajoukon kartuttamiseen. Puhelinlaitteista tällaista kerättävää dataa ovat muun muassa tieto suorituksessa olevista ja asennetuista sovelluksista, erilaiset järjestelmäasetukset, kuten verkkoyhteystiedot ja näytön kirkkaus, sekä lukuisat muut järjestelmätason parametrit, kuten suorittimen ja muistin käyttö. Automaattista datan keräystä voidaan täydentää käyttäjille lähetettävillä kyselyillä. Älypuhelimista kerättävän datan analysoinnissa on monia vaiheita, jotka tekevät koko prosessista haasteellisen. Automaattisesti kerättyyn dataan päätyy helposti virheitä ja puutteita, joiden käsittely on hallittava. Datan määrä kasvaa helposti teratavuluokkaan, jolloin analysointiin tarvitaan suurten datajoukkojen käsittelyyn sopivia hajautettuja laskenta-alustoja ja algoritmeja. Hyödyllisten suositusten generoimiseksi puhelinlaitteisiin liittyvän analyysin halutaan usein olevan reaaliaikaista, mikä asettaa lisää haasteita analyysin suorituskyvylle. Tässä väitöskirjassa esitetään menetelmiä joukkoistetusti havainnoidun älypuhelindatan käsittelemiseksi tehokkaasti ja hyödyllistä informaatiota tuottaen. Väitöskirjan alussa kuvaillaan älypuhelindatan keräämistä prosessina, datan esikäsittelyä ja siistimistä hyödylliseen ja käsiteltävään muotoon. Väitöskirja esittää, että puhelinlaitteen tila tulisi ottaa huomioon kokonaisuutena, jossa useat eri tekijät, kuten samanaikaisesti suoritettavat sovellukset ja toisiinsa liittyvät järjestelmäasetukset vaikuttavat toisiinsa. Tämän jälkeen väitöskirjassa esitetään joitakin sopivia tilastollisen analyysin ja koneoppimisen menetelmiä, joita väitöskirjan tutkimuksessa on käytetty älypuhelindatan analysointiin. Kaikki näistä menetelmistä ovat suoritettavissa hajautetussa laskentaympäristössä ja toteutettu Apache Spark -järjestelmää käyttäen. Lopuksi väitöskirja näyttää, kuinka analyysiä sovelletaan käytännössä käyttäjille suunnatun palautteen ja suositusten generointiin. Päähuomion saavat puhelinlaitteiden energiankulutuksen analysointi, puhelinsovellusten trendien havainnointi, ja erilaisten kulttuuristen ja sosioekonomisten taustatekijöiden huomiointi mobiilikäyttöä tutkittaessa

Inferring Context of Mobile Data Crowdsensed in the Wild

International audienceUnderstanding the sensing context of raw data is crucial for assessing the quality of large crowdsourced spatio-temporal datasets. Accelerometer's precision can vary considerably depending on whether the phone is in-pocket or out-pocket, i.e., held in hand. GPS accuracy can be very low in places like underground metro stations. Further, jump-lengths are shorter and have higher frequency when a person is indoor. Hence, we focus on contexts such as in/out-pocket, under/over-ground, and in/out-door that can be essential for reliably inferring human mobility attributes and properties (e.g., location, jump-length, and mobility activity like walking or driving) from crowdsensed data. Our work is motivated by the fact that most of the publicly available crowdsensing datasets (e.g. PRIVA'MOV and Beijing taxi dataset) do not include data from specialized sensors such as light, barometer, etc. considered by state-of-the-art algorithms for detecting the above mentioned contexts. Therefore, we focus on mining context from the limited features available in the publicly available mobility related crowdsensing datasets. Moreover, as ground truth is typically not available in these datasets, we pay special attention to minimizing the training or tuning efforts of the introduced algorithms. Our algorithms are unsupervised binary classifiers with a small memory footprint and execution time. As the lack of certain features prohibits us to consider state-of-the-art algorithms as baselines, we compare the performance of our heuristic algorithms against Machine Learning (ML) models built by an AutoML tool using the same set of features. Our experimental evaluation with a segment of the Ambiciti dataset demonstrates that when compared to the best baseline ML model w.r.t. balanced accuracy (see Table I), our algorithm for in/out-pocket performs equally well, while for under/over-ground and in/out-door contexts, for a specific hyper-parameter, our corresponding algorithms are within 4.3% and 1%, respectively. Concerning memory, our algorithms require 0kB, 4kB, and 0kB, respectively, while they take 0.08sec, 0.17sec and 0.003sec, respectively, for execution. Our algorithms are lightweight enough to be integrated into smartphone applications. Context information mined onboard thus remains private and can be used to annotate users' personal trajectories and incentivize them to participate in crowd-measurement campaigns