XRay: Enhancing the Web's Transparency with Differential Correlation

Today's Web services - such as Google, Amazon, and Facebook - leverage user data for varied purposes, including personalizing recommendations, targeting advertisements, and adjusting prices. At present, users have little insight into how their data is being used. Hence, they cannot make informed choices about the services they choose. To increase transparency, we developed XRay, the first fine-grained, robust, and scalable personal data tracking system for the Web. XRay predicts which data in an arbitrary Web account (such as emails, searches, or viewed products) is being used to target which outputs (such as ads, recommended products, or prices). XRay's core functions are service agnostic and easy to instantiate for new services, and they can track data within and across services. To make predictions independent of the audited service, XRay relies on the following insight: by comparing outputs from different accounts with similar, but not identical, subsets of data, one can pinpoint targeting through correlation. We show both theoretically, and through experiments on Gmail, Amazon, and YouTube, that XRay achieves high precision and recall by correlating data from a surprisingly small number of extra accounts.Comment: Extended version of a paper presented at the 23rd USENIX Security Symposium (USENIX Security 14

Reorganization of sea urchin gene regulatory networks at least 268 million years ago as revealed by oldest fossil cidaroid echinoid

Echinoids, or sea urchins, are rare in the Palaeozoic fossil record, and thus the details regarding the early diversification of crown group echinoids are unclear. Here we report on the earliest probable crown group echinoid from the fossil record, recovered from Permian (Roadian-Capitanian) rocks of west Texas, which has important implications for the timing of the divergence of crown group echinoids. The presence of apophyses and rigidly sutured interambulacral areas with two columns of plates indicates this species is a cidaroid echinoid. The species, Eotiaris guadalupensis, n. sp. is therefore the earliest stem group cidaroid. The occurrence of this species in Roadian strata pushes back the divergence of cidaroids and euechinoids, the clades that comprise all living echinoids, to at least 268.8 Ma, ten million years older than the previously oldest known cidaroid. Furthermore, the genomic regulation of development in echinoids is amongst the best known, and this new species informs the timing of large-scale reorganization in echinoid gene regulatory networks that occurred at the cidaroid-euechinoid divergence, indicating that these changes took place by the Roadian stage of the Permian

The self-reported quality of life of Lithuanian children with asthma was comparable to Western populations

This study received European Finding from the Improvement of Training of High Qualification Specialists for the Development of Research-Intensive Economic Sub-Sectors – NKPDOKT structural support project (project number VP1-3.1-ŠMM-01-V-03-001).Peer reviewedPostprin

Why the (dis)agreement? Family context and child-parent perspectives on health-related quality of life and psychological problems in paediatric asthma

Introduction. Children’s health-related quality of life (HrQoL) and psychological problems are important outcomes to consider in clinical decision making in pediatric asthma. However, children’s and parents’ reports often differ. The present study aimed to examine the levels of agreement/disagreement between children’s and parents’ reports of HrQoL and psychological problems and to identify socio-demographic, clinical and family variables associated with the extent and direction of (dis)agreement. Method. The sample comprised 279 dyads of Portuguese children with asthma who were between 8 and 18 years of age (M = 12.13; SD = 2.56) and one of their parents. The participants completed self- and proxy-reported questionnaires on pediatric generic HrQoL (KIDSCREEN-10), chronic-generic HrQoL (DISABKIDS-37) and psychological problems (Strengths and Difficulties Questionnaire). Children’s and parents’ perceptions of family relationships were measured with the Family Environment Scale and the caregiving burden was assessed using the Revised Burden Measure. Results. The child-parent agreement on reported HrQoL and psychological problems was poor to moderate (intraclass correlation coefficients between .32 and .47). The rates of child-parent discrepancies ranged between 52.7% (psychological problems) and 68.8% (generic HrQoL), with 50.5% and 31.5% of the parents reporting worse generic and chronic-generic HrQoL, respectively, and 33.3% reporting more psychological problems than their children. The extent and direction of disagreement were better explained by family factors than by socio-demographic and clinical variables: a greater caregiving burden was associated with increased discrepancies in both directions and children’s and parents’ perceptions of less positive family relationships were associated with discrepancies in different directions. Conclusion. Routine assessment of pediatric HrQoL and psychological problems in healthcare and research contexts should include self- and parent-reported data as complementary sources of information, and also consider the family context. The additional cost of conducting a more in-depth assessment of pediatric adaptation outcomes can be offset through more efficient allocation of health resources.This study was supported by the R&D Unit Institute of Cognitive Psychology, Vocational and Social Development of the University of Coimbra (PEst-OE/PSI/UI0192/2011); and by the Portuguese Foundation for Science and Technology (PhD Grant SFRH/BD/69885/2010)

Compiler-assisted Adaptive Software Testing

Modern software is becoming increasingly complex and is plagued with vulnerabilities that are constantly exploited by attackers. The vast numbers of bugs found in security-critical systems and the diversity of errors presented in commercial off-the-shelf software require effective, scalable testing frameworks. Unfortunately, the current testing ecosystem is heavily fragmented, with the majority of toolchains targeting limited classes of errors and applications without offering provably strong guarantees. With software codebases continuously becoming more diverse and complex, the large-scale deployment of monolithic, non-adaptive analysis engines is likely to increase the aforementioned fragmentation. Instead, modern software testing requires adaptive, hybrid techniques that target errors selectively. This dissertation argues that adopting context-aware analyses will enable us to set the foundations for retargetable testing frameworks while further increasing the accuracy and extensibility of existing toolchains. To this end, we initially examine how compiler analyses can become context-aware, prioritizing certain errors over others of the same type. As a use case of our proposed approach, we extend a state-of-the-art compiler's integer error detection pipeline to suppress reports of benign errors by up to 89% in real-world workloads, while allowing for reporting of serious errors. Subsequently, we demonstrate how compiler-based instrumentation can be utilized by feedback-driven evolutionary fuzzers to provide multifaceted analyses targeting broader classes of bugs. In this direction, we present differential diversity (δ-diversity), we propose a generic methodology for offering state-aware guidance in feedback-driven frameworks, and we demonstrate how to retrofit state-of-the-art fuzzers to target broader classes of errors. We provide two such prototype implementations: NEZHA, the first differential generic fuzzer capable of handling logic bugs, as well as SlowFuzz, the first generic fuzzer targeting complexity vulnerabilities. We applied both prototypes on production software, and demonstrate their effectiveness. We found that NEZHA discovered hundreds of logic discrepancies across a wide variety of applications (SSL/TLS libraries, parsers, etc.), while SlowFuzz successfully generated inputs triggering slowdowns in complex, real-world software, including zip parsers, regular expression libraries, and hash table implementations

Data fusion algorithms development for a spatially dispersed system of bistatic radar sensors for three dimensional multiple target tracking

During the last decade, the sensor technology advances together with the enormous computational power increase, have led to the replacement of complex and expensive sensors with systems of multiple simple low cost spatially distributed sensors. Key role towards this direction possesses the development of modern, efficient and computationally feasible data processing algorithms. The multistatic radar consists a system of multiple spatially distributed bistatic radar sensors, with main objective the detection and tracking of multiple targets in the field of view. The bistatic principle and the low frequency use, increase the probability of detection of targets with low radar cross section due to shaping, radar absorbent materials or small size. The use of multiple bistatic receivers lends to the system characteristics of survivability and robustness. The simple operation principle of each bistatic sensor forces the use of complex data processing algorithms at the central fusion node where all the bistatic measurements are processed for the three dimensional position and velocity extraction of each target. Main objective of this doctoral thesis is the study and selection of the appropriate data processing algorithms for the multistatic radar central station. Firstly, the basic system principles of operation are presented, the bistatic receiver local data processing is then outlined and experimental results of a first lab prototype are reported. Thorough investigation of filtering, data association, track management and data fusion algorithms is conducted. The most proper algorithm, concerning track accuracy and consistency, reliability, practicality, robustness, simplicity and computational feasibility, for each process is afterwards selected through analytical simulations. Finally, a thorough performance evaluation of the proposed composite data processing algorithm is presented. The algorithm and system performance was evaluated not only through comprehensive simulation, since an experimental multistatic radar prototype was constructed and tested as well.Την τελευταία δεκαετία, η ανάπτυξη της επιστήμης των αισθητήρων και η ραγδαία αύξηση της υπολογιστικής ισχύος, οδήγησαν στην αντικατάσταση των σύνθετων και ακριβών αισθητήρων του παρελθόντος από συστήματα πολλαπλών χωρικά κατανεμημένων αισθητήρων χαμηλού κόστους. Βασικό ρόλο στην κατεύθυνση αυτή έπαιξε η ανάπτυξη σύγχρονων, αποτελεσματικών και υπολογιστικά εφικτών αλγορίθμων επεξεργασίας δεδομένων πολλαπλών αισθητήρων. Το πολυστατικό σύστημα ραντάρ αποτελεί ένα σύστημα πολλαπλών, χωρικά κατανεμημένων διστατικών αισθητήρων ραντάρ με κύριο σκοπό την ανίχνευση και παρακολούθηση στόχων μικρής ενεργού επιφάνειας ραντάρ. Η διστατική αρχή και η χρήση χαμηλών συχνοτήτων αυξάνουν την πιθανότητα ανίχνευσης στόχων με μικρή ενεργό επιφάνεια ραντάρ, είτε λόγω σχηματοποίησης ή χρήσης απορροφητικών υλικών, είτε λόγω μικρού μεγέθους αντίστοιχα. Η πολυστατικότητα προσδίδει επίσης χαρακτηριστικά επιβιωσιμότητας και ανθεκτικότητας στο σύστημα. Η απλή λειτουργία του κάθε διστατικού αισθητήρα επιβάλλει τη χρήση εξειδικευμενών αλγορίθμων επεξεργασίας δεδομένων στον κεντρικό κόμβο σύντηξης δεδομένων, όπου συγκεντρώνονται όλα τα δεδομένα για την εξαγωγή της τρισδιάστατης θέσης και ταχύτητας κάθε στόχου που βρίσκεται μέσα στην περιοχή επιτήρησης του συστήματος. Κύριο αντικείμενο της παρούσης διδακτορικής διατριβής αποτελεί η μελέτη και επιλογή των κατάλληλων αλγορίθμων επεξεργασίας δεδομένων για τον κεντρικό σταθμό του πολυστατικού συστήματος ραντάρ. Αφού πρώτα παρουσιάζονται συνοπτικά οι βασικές αρχές λειτουργίας του συστήματος, μελετάται η τοπική επεξεργασία δεδομένων στον κάθε διστατικό αισθητήρα ραντάρ και παρουσιάζονται τα πειραματικά αποτελέσματα ενός εργαστηριακού πρωτοτύπου διστατικού ραντάρ που κατασκευάσθηκε αρχικά. Στη συνέχεια μελετιόνται διεξοδικά οι αλγόριθμοι εκτίμησης κατάστασης στόχου, συσχέτισης δεδομένων, διαχείρισης ιχνών και σύντηξης δεδομένων που θα μπορούσαν να χρησιμοποιηθούν. Μέσω εκτενών προσομοιώσεων επιλέγεται η κατάλληλη μέθοδος για κάθε διαδικασία, με κριτήριο την βέλτιστη ακρίβεια παρακολούθησης σε συνδυασμό με την ελάχιστη υπολογιστική πολυπλοκότητα, την πρακτικότητα, την αξιοπιστία και την απλότητα. Τελικά, αξιολογείται η απόδοση του προτεινόμενου αλγορίθμου συνολικά, που αποτελεί συνδυασμό των επιλεγμένων μεθόδων. Η αξιολόγηση γίνεται όχι μόνο μέσω εκτενών προσομοιώσεων αλλά και σε πραγματικές συνθήκες καθώς κατασκευάστηκε ένα πειραματικό πρωτότυπο πολυστατικό σύστημα το οποίο και δοκιμάστηκε με απόλυτη επιτυχία σε συνθήκες πραγματικού χρόνου και περιβάλλοντος