Tell Me Your Ads and I'll Tell You Who You Are

Google AdSense, one of the most popular Online Advertise Networks, uses a mix of two techniques to deliver ads: contextual ads and behavioral ads, but it is not clear when or how much of the both they actually use. In this work, we raise several concerns regarding behavioral ads. End-users have very little control: once behavioral ads are allowed (which is the default setting), it is hard to predict what part about a user's past interests they will reveal. Our goal in this work is to understand and quantify the loss of online privacy through behavioral advertising

Interdependent and Multi-Subject Privacy: Threats, Analysis and Protection

In Alan Westin's generally accepted definition of privacy, he describes it as an individual's right 'to control, edit, manage, and delete information about them[selves] and decide when, how, and to what extent information is communicated to others.' Therefore, privacy is an individual and independent human right. The great Mahatma Gandhi once said that 'interdependence is and ought to be as much the ideal of man as selfsufficiency. Man is a social being.' To ensure this independent right to inherently social beings, it will be difficult, if not impossible. This is especially true as today's world is highly interconnected, technology evolves rapidly, data sharing is increasingly abundant, and regulations do not provide sufficient guidance in the realm of interdependency. In this thesis, we explore the topic of interdependent privacy from an adversarial point of view by exposing threats, as well as from an end-user point of view, by exploring awareness, preferences and privacy protection needs. First, we quantify the effect of co-locations on location privacy, considering an adversary such as a social-network operator that has access to this information: Not only can a user be localized due to her reported locations and mobility patterns, but also due to those of her friends (and the friends of her friends and so on). We formalize this problem and propose effective inference algorithms that substantially reduce the complexity of localization attacks that make use of co-locations. Our results show that an adversary can effectively incorporate co-locations in attacks to substantially reduce users' location privacy; this exposes a real and severe threat. Second, we investigate the interplay between the privacy risks and the social benefits of users when sharing (co-)locations on OSNs. We propose a game-theoretic framework for analyzing users' strategic behaviors. We conduct a survey of Facebook users and quantify their benefits of sharing vs. viewing information and their preference for privacy vs. benefits. Our survey exposes deficits in users' awareness of privacy risks in OSNs. Our results further show how users' individual preferences influence, sometimes in a negative way, each other's decisions. Third, we consider various types of interdependent and multi-subject data (photo, colocation, genome, etc.) that often have privacy implications for data subjects other than the uploader, yet can be shared without their consent or awareness. We propose a system for sharing such data in a consensual and privacy-preserving manner. We implement it in the case of photos, by relying on image-processing and cryptographic techniques, as well as on a two-tier architecture. We conduct a survey of Facebook users; it indicates that there is interest in such a system, and that users have increasing privacy concerns due to prejudice or discrimination that they have been or could still easily be exposed to. In conclusion, this thesis provides new insights on users' privacy in the context of interdependence and constitutes a step towards the design of novel privacy-protection mechanisms. It should be seen as a warning message for service providers and regulatory institutions: Unless the interdependent aspects of privacy are considered, this fundamental human right can never be guaranteed

The (Co)-Location Sharing Game

Most popular location-based social networks, such as Facebook and Foursquare, let their (mobile) users post location and co-location (involving other users) information. Such posts bring social benefits to the users who post them but also to their friends who view them. Yet, they also represent a severe threat to the users’ privacy, as co-location information introduces interdependences between users. We propose the first game-theoretic framework for analyzing the strategic behaviors, in terms of information sharing, of users of OSNs. To design parametric utility functions that are representative of the users’ actual preferences, we also conduct a survey of 250 Facebook users and use conjoint analysis to quantify the users’ benefits of sharing vs. viewing (co)-location information and their preference for privacy vs. benefits. Our survey findings expose the fact that, among the users, there is a large variation, in terms of these preferences. We extensively evaluate our framework through data-driven numerical simulations. We study how users’ individual preferences influence each other’s decisions, we identify several factors that significantly affect these decisions (among which, the mobility data of the users), and we determine situations where dangerous patterns can emerge (e.g., a vicious circle of sharing, or an incentive to over-share) – even when the users share similar preferences

Location Privacy with Probabilistic Co-Location Profiles [work in progress]

International audienceData collected from location-based applications could have an impact on the location privacy of users. Several works concern protection privacy of users that share our own locations. As concern co-location information, some new studies start to show their implication in location privacy declining. This paper is a preliminary contribution in this direction and its purpose is to highlight a first result in our work. We quantify the impact of implicit co-location information by a simple algorithm able to improve the probability of inference of a base line algorithm

Quantifying Interdependent Privacy Risks with Location Data

International audienceCo-location information about users is increasingly available online. For instance, mobile users more and more frequently report their co-locations with other users in the messages and in the pictures they post on social networking websites by tagging the names of the friends they are with. The users' IP addresses also constitute a source of co-location information. Combined with (possibly obfuscated) location information, such co-locations can be used to improve the inference of the users' locations, thus further threatening their location privacy: As co-location information is taken into account, not only a user's reported locations and mobility patterns can be used to localize her, but also those of her friends (and the friends of their friends and so on). In this paper, we study this problem by quantifying the effect of co-location information on location privacy, considering an adversary such as a social network operator that has access to such information. We formalize the problem and derive an optimal inference algorithm that incorporates such co-location information, yet at the cost of high complexity. We propose some approximate inference algorithms, including a solution that relies on the belief propagation algorithm executed on a general Bayesian network model, and we extensively evaluate their performance. Our experimental results show that, even in the case where the adversary considers co-locations of the targeted user with a single friend, the median location privacy of the user is decreased by up to 62% in a typical setting. We also study the effect of the different parameters (e.g., the settings of the location-privacy protection mechanisms) in different scenarios

PERSPECTIVES AND LIMITS OF MANDIBULAR LATERAL INCISOR INTRUSION ASSOCIATED WITH PERIODONTAL DISEASE. A FEM STUDY

Introduction. FEM is a reliable tool for researching the impact of orthodontic therapy on the affected periodontal tissues. Material and methods. Using Catia V5R16 and Abaqus software we analysed various clinical scenarios for intruding the lateral mandibular incisor in different situations of horizontal bone loss (HBL). Results and Discussions. When intruding the lateral mandibular incisors we noticed that the equivalent tensions are increasing together with the extent of HBL and the magnitude of the applied force. Conclusions. When optimal intrusive forces are applied at the level of the mandibular lateral incisor, the periodontal status of the patient will not represent a restriction for the interdisciplinary treatment

Specificity of Sustainable Structural Dynamics of Local Economy in Romanian Tourist Resorts

The lack of sustainable development strategies of the tourist resorts from Romania caused the structural dynamics of their economy to record large fluctuations under the impact of determinants with unpredictable developments. The spectacular dynamics have led to developments difficult to predict, in many situations that generate environmental conflicts, where the economic pressure has exceeded the support capacity of the natural environment. In this study, we aim to analyze the dynamic relationship between tourism and the other components of the economy, from each resort from Romania. The significant growth of tourism in recent years requires new approaches, relevant for understanding the role of tourism in increasing the complexity of the local economy. Measuring the role of tourism in the development of local economy was achieved by building an economic database for all tourist resorts from Romania (according to Government Decision No. 107 of 2018), at the four-digit NACE code level (Classification of National Economy Activities), for the economic indicators considered relevant: number of companies, number of employees, and turnover and profit, for the period 2000–2016, as well as at territorial administrative unit level. Detailed analyses revealed very different structural dynamics, the spectacular dynamics, lacking a coherent strategic framework, led in all situations to the emergence of environmental conflicts. Tourist resorts in which tourism has become an essential component of economic development have based their development on capitalization of local resources, which led to multiplication effects, materialized in a spectacular evolution of the local economy, and an increasing pressure on the natural environment