Towards trajectory anonymization: a generalization-based approach

Trajectory datasets are becoming popular due to the massive usage of GPS and locationbased services. In this paper, we address privacy issues regarding the identification of individuals in static trajectory datasets. We first adopt the notion of k-anonymity to trajectories and propose a novel generalization-based approach for anonymization of trajectories. We further show that releasing anonymized trajectories may still have some privacy leaks. Therefore we propose a randomization based reconstruction algorithm for releasing anonymized trajectory data and also present how the underlying techniques can be adapted to other anonymity standards. The experimental results on real and synthetic trajectory datasets show the effectiveness of the proposed techniques

Position discovery for a system of bouncing robots

International audienceA collection of n anonymous mobile robots is deployed on a unit-perimeter ring or a unit-length line segment. Every robot starts moving at constant speed, and bounces each time it meets any other robot or segment endpoint, changing its walk direction. We study the problem of position discovery, in which the task of each robot is to detect the presence and the initial positions of all other robots. The robots cannot communicate or perceive information about the environment in any way other than by bouncing nor they have control over their walks which are determined by their initial positions and their starting directions. Each robot has a clock allowing it to observe the times of its bounces. We give complete characterizations of all initial configurations for both the ring and the segment in which no position detection algorithm exists and we design optimal position detection algorithms for all feasible configurations

Towards trajectory anonymization: A generalization-based approach

Trajectory datasets are becoming,popular,due,to the massive,usage,of GPS and,location- based services. In this paper, we address privacy issues regarding the identification of individuals in static trajectory datasets. We first adopt the notion of k-anonymity,to trajectories and propose,a novel generalization-based approach,for anonymization,of trajectories. We further show,that releasing anonymized,trajectories may,still have,some,privacy,leaks. Therefore we propose,a randomization based,reconstruction,algorithm,for releasing anonymized,trajectory data and,also present how,the underlying,techniques,can be adapted,to other anonymity,standards. The experimental,results on real and,synthetic trajectory datasets show,the effectiveness of the proposed,techniques

Exploring historical location data for anonymity preservation in location-based services

We present a new approach for K-anonymity protection in Location-Based Services (LBSs). Specifically, we depersonalize location information by ensuring that each location reported for LBSs is a cloaking area that contains K different footprints--- historical locations of different mobile nodes. Therefore, the exact identity and location of the service requestor remain anonymous from LBS service providers. Existing techniques, on the other hand, compute the cloaking area using current locations of K neighboring hosts of the service requestor. Because of this difference, our approach significantly reduces the cloaking area, which in turn decreases query processing and communication overhead for returning query results to the requesting host. In addition, existing techniques also require frequent location updates from all nodes, regardless of whether or not these nodes are requesting LBSs. Most importantly, our approach is the first practical solution that provides K-anonymity trajectory protection needed to ensure anonymity when the mobile host requests LBSs continuously as it moves. Our solution depersonalizes a user\u27s trajectory (a time-series of the user\u27s locations) based on the historical trajectories of other users

Contribution of the voluntary sector to mental health crisis care in England: protocol for a multimethod study.

Introduction - Timely access to the right kind of support for people experiencing a mental health crisis can be problematic. The voluntary sector (VS) plays a key role in providing support and enabling access, but there is a knowledge gap concerning its contribution and interface with public services in mental health crisis care. Methods and analysis - This study aims to address this. The study has three empirical elements: (1) a national survey of voluntary sector organisations (VSOs) in England and national stakeholder interviews to develop a typology of organisations and interventions provided by VSOs; (2) detailed mapping of VS services in two regions through interviews and extending the national survey; (3) four case studies, identified from the regional mapping, of VS mental health crisis services and their interface with National Health Service (NHS) and local authority services, at both a system and individual level. Data collection will involve interviews with commissioners; VSO and NHS or local authority providers; and focus groups with people who have experience of VSO crisis support, both service users and carers; and mapping the crisis trajectory of 10 service users in each study site through narrative interviews with service users and informal carers to understand the experience of VSO crisis care and its impact. Ethics and dissemination - The University of Birmingham Humanities and Social Sciences Ethical Review Committee granted ethical approval (reference ERN_16-1183) for the national and regional elements of the study. Ethical review by the Health Research Authority will be required for the case study research once the sites have been identified from the first two elements of the study. A range of methods including a policy seminar, publication in academic journals and a tool kit for commissioners and practitioners will be produced to maximise the impact of the findings on policy and practice

David Stafford-Clark (1916-1999): seeing through a celebrity psychiatrist

This article uses the mass-media career of the British psychiatrist David Stafford-Clark (1916-1999) as a case study in the exercise of cultural authority by celebrity medical professionals in post-war Britain. Stafford-Clark rose to prominence in the mass media, particularly through his presenting work on medical and related topics for BBC TV and Radio, and was in the vanguard of psychiatrists and physicians who eroded professional edicts on anonymity. At the height of his career, he traded upon his celebrity status, and consequent cultural authority, to deliver mass media sermons on a variety of social, cultural, and political topics. Stafford-Clark tried to preserve his sense of personal and intellectual integrity by clinging to a belief that his authority in the public sphere was ultimately to be vindicated by his literary, intellectual, and spiritual significance. But as his credibility dwindled, he came to distrust the cultural intermediaries, such as broadcasters and publishers, who had supported him

Schizoid subjectivities? : Re-theorizing teen girls’ sexual cultures in an era of ‘sexualization’

Drawing on three case studies from two UK ethnographic research projects in urban and rural working-class communities, this article explores young teen girls’ negotiation of increasingly sex-saturated societies and cultures. Our analysis complicates contemporary debates around the ‘sexualization’ moral panic by troubling developmental and classed accounts of age-appropriate (hetero)sexuality. We explore how girls are regulated by, yet rework and resist expectations to perform as agentic sexual subjects across a range of spaces (e.g. streets, schools, homes, cyberspace). To conceptualize the blurring of generational and sexual binaries present in our data, we develop Deleuzian notions of ‘becomings’, ‘assemblages’ and ‘schizoid subjectivities’. These concepts help us to map the anti-linear transitions and contradictory performances of young femininity as always in-movement; where girls negotiate discourses of sexual knowingness and innocence, often simultaneously, yet always within a wider context of socio-cultural gendered/classed regulations

Deterministic Symmetry Breaking in Ring Networks

We study a distributed coordination mechanism for uniform agents located on a circle. The agents perform their actions in synchronised rounds. At the beginning of each round an agent chooses the direction of its movement from clockwise, anticlockwise, or idle, and moves at unit speed during this round. Agents are not allowed to overpass, i.e., when an agent collides with another it instantly starts moving with the same speed in the opposite direction (without exchanging any information with the other agent). However, at the end of each round each agent has access to limited information regarding its trajectory of movement during this round. We assume that $n$ mobile agents are initially located on a circle unit circumference at arbitrary but distinct positions unknown to other agents. The agents are equipped with unique identifiers from a fixed range. The {\em location discovery} task to be performed by each agent is to determine the initial position of every other agent. Our main result states that, if the only available information about movement in a round is limited to %information about distance between the initial and the final position, then there is a superlinear lower bound on time needed to solve the location discovery problem. Interestingly, this result corresponds to a combinatorial symmetry breaking problem, which might be of independent interest. If, on the other hand, an agent has access to the distance to its first collision with another agent in a round, we design an asymptotically efficient and close to optimal solution for the location discovery problem.Comment: Conference version accepted to ICDCS 201