Marginal Release Under Local Differential Privacy

Many analysis and machine learning tasks require the availability of marginal statistics on multidimensional datasets while providing strong privacy guarantees for the data subjects. Applications for these statistics range from finding correlations in the data to fitting sophisticated prediction models. In this paper, we provide a set of algorithms for materializing marginal statistics under the strong model of local differential privacy. We prove the first tight theoretical bounds on the accuracy of marginals compiled under each approach, perform empirical evaluation to confirm these bounds, and evaluate them for tasks such as modeling and correlation testing. Our results show that releasing information based on (local) Fourier transformations of the input is preferable to alternatives based directly on (local) marginals

Private Multiplicative Weights Beyond Linear Queries

A wide variety of fundamental data analyses in machine learning, such as linear and logistic regression, require minimizing a convex function defined by the data. Since the data may contain sensitive information about individuals, and these analyses can leak that sensitive information, it is important to be able to solve convex minimization in a privacy-preserving way. A series of recent results show how to accurately solve a single convex minimization problem in a differentially private manner. However, the same data is often analyzed repeatedly, and little is known about solving multiple convex minimization problems with differential privacy. For simpler data analyses, such as linear queries, there are remarkable differentially private algorithms such as the private multiplicative weights mechanism (Hardt and Rothblum, FOCS 2010) that accurately answer exponentially many distinct queries. In this work, we extend these results to the case of convex minimization and show how to give accurate and differentially private solutions to *exponentially many* convex minimization problems on a sensitive dataset

TRA-954: SOLUTION MODEL FOR URBAN TRAFFIC CONGESTION: EGYPTIAN CASE STUDY

Traffic congestion is a major problem in many cities around the world resulting in massive delays, increased fuel wastage, environmental impact and other negative consequences affecting the daily life of each individual. From a transportation engineering point of view, making the correct decision to eliminate such congestion problems can be very difficult for decision-makers who carry the burden of analyzing large quantities of data which could be vague and conflicting in nature. Therefore, an effective and consistent system is required to simplify the decision-making process of the traffic congestion control. Traffic simulation could be that tool. The seriousness of traffic congestion in Egypt is the main motive for the study presented herein. The study aims at developing a model that sets guidelines on how to approach an urban congested traffic area, be able to tackle the problem and choose the effective engineering solution in terms of either geometry and/or structure. Sectors of El Nasr Road, Cairo with a total length of 2.4 km is chosen as a typical example of an urban area with traffic congestion hotspots. It serves as an excellent location to implement the traffic solution model on. The model is developed and implemented as follows: collection of traffic data, diagnosis of the congestion problems in terms of social, commercial, cultural, and behavioral aspects. The analysis of the data finger points out the flag areas by conducting total and peak traffic volume counts, simulation of the existing traffic conditions to get the delayed travel times of vehicles in that area. The analysis of the output would finally help decide whether such problem would be solved by geometric adjustments of the surface or the problem requires a multi-layered intersection

Patterns in rational base number systems

Number systems with a rational number $a/b > 1$ as base have gained interest in recent years. In particular, relations to Mahler's 3/2-problem as well as the Josephus problem have been established. In the present paper we show that the patterns of digits in the representations of positive integers in such a number system are uniformly distributed. We study the sum-of-digits function of number systems with rational base $a/b$ and use representations w.r.t. this base to construct normal numbers in base $a$ in the spirit of Champernowne. The main challenge in our proofs comes from the fact that the language of the representations of integers in these number systems is not context-free. The intricacy of this language makes it impossible to prove our results along classical lines. In particular, we use self-affine tiles that are defined in certain subrings of the ad\'ele ring $\mathbb{A}_\mathbb{Q}$ and Fourier analysis in $\mathbb{A}_\mathbb{Q}$. With help of these tools we are able to reformulate our results as estimation problems for character sums

A physical layer network coding based modify-and-forward with opportunistic secure cooperative transmission protocol

This paper investigates a new secure relaying scheme, namely physical layer network coding based modify-and-forward (PMF), in which a relay node linearly combines the decoded data sent by a source node with an encrypted key before conveying the mixed data to a destination node. We first derive the general expression for the generalized secrecy outage probability (GSOP) of the PMF scheme and then use it to analyse the GSOP performance of various relaying and direct transmission strategies. The GSOP performance comparison indicates that these transmission strategies offer different advantages depending on the channel conditions and target secrecy rates, and relaying is not always desirable in terms of secrecy. Subsequently, we develop an opportunistic secure transmission protocol for cooperative wireless relay networks and formulate an optimisation problem to determine secrecy rate thresholds (SRTs) to dynamically select the optimal transmission strategy for achieving the lowest GSOP. The conditions for the existence of the SRTs are derived for various channel scenarios

Gene expression profiling of noninvasive primary urothelial tumours using microarrays

At present, the mechanism leading to bladder cancer is still poorly understood, and our knowledge about early events in tumorigenesis is limited. This study describes the changes in gene expression occurring during the neoplastic transition from normal bladder urothelium to primary Ta tumours. Using DNA microarrays, we identified novel differentially expressed genes in Ta tumours compared to normal bladder, and genes that were altered in high-grade tumours. Among the mostly changed genes between normal bladder and Ta tumours, we found genes related to the cytoskeleton (keratin 7 and syndecan 1), and transcription (high mobility group AT-hook 1). Altered genes in high-grade tumours were related to cell cycle (cyclin-dependent kinase 4) and transcription (jun d proto-oncogene). Furthermore, we showed the presence of high keratin 7 transcript expression in bladder cancer, and Western blotting analysis revealed three major molecular isoforms of keratin 7 in the tissues. These could be detected in urine sediments from bladder tumour patients

The effect of image interactivity technology on the consumer experience : the case of hotels'websites

Cette thèse analyse l'effet de la Technologie d'Image Interactive (TII) sur l'expérience des consommateurs sur les sites web hôteliers. La TII est une fonctionnalité interactive permettant à l'utilisateur de modifier les caractéristiques de l'environnement en question afin d'imiter, ou même surpasser, l’expérience directe avec celui-ci mais dans un contexte virtuel. Malgré l’attractivité de cette technologie en marketing, son influence sur le comportement des consommateurs n'est pas entièrement prouvée et ses effets positifs ne sont pas toujours évidents. Elle requière d'ailleurs - des budgets - parfois substantiels - ; d'où l'intérêt de comparer l'efficacité de ses formes avant de les mettre en place. Ce travail doctoral cherche à identifier la forme qui favoriserait une expérience et des réponses optimales des consommateurs en répondant à la problématique suivante : "Dans quelle mesure la TII influence-t-elle l'expérience en ligne des voyageurs lors de la réservation hôtelière ainsi que leurs réponses comportementales ? Dans quelle mesure la perception de son interactivité joue-t-elle un rôle à cet égard ?". Par des études qualitatives et quantitatives, cette recherche met en correspondance les avis des professionnels et des vrais de consommateurs. Elle met en évidence le rôle médiateur de la perception de l'interactivité dans l'explication des effets de la TII sur l'expérience et le comportement des consommateurs. Ceci, en prenant en compte l'effet modérateur de certains traits individuels et situationnels. Ce faisant, ce travail met en perspective des implications théoriques, méthodologiques et managériales et propose de nouvelles pistes de recherches.This thesis analyzes the effect of Interactive Image Technology (IIT) on the consumer experience on hotel websites. IIT is an interactive functionality allowing the user to modify the characteristics of the environment in question in order to imitate, or even surpass, the direct experience with it but in a virtual context. Despite the attractiveness of this technology in marketing, its influence on consumer behavior is not fully proven and its positive effects are not always obvious. It also requires - budgets - sometimes substantial -; hence the interest of comparing the effectiveness of its forms before implementing them. This doctoral work seeks to identify the form that would promote an optimal consumer experience and responses by answering the following question: "To what extent does IIT influence the online experience of travelers when booking hotels as well as their behavioral responses? To what extent does the perception of its interactivity play a role in this regard? Through qualitative and quantitative studies, this research matches the opinions of professionals and real consumers. It highlights the mediating role of the perception of interactivity in explaining the effects of IIT on consumer experience and behavior. This, taking into account the moderating effect of certain individual and situational traits. In doing so, this work puts into perspective theoretical, methodological and managerial implications and proposes new avenues for research