Private Information Retrieval (PIR) protocols aim at ensuring a user that he can retrieve some part Di of a distributed database D without revealing the index i to the server(s). Most of known PIR protocols focus on decreasing the communication complexity between the client and the server(s). Recently, the use of PIR codes by Fazeli et. al. also lead to a huge reduction of the storage overhead ...

It is a well-known fact that the direct storing and comparison of the histogram for the purpose of content-based image retrieval (CBIR) is inefficient in terms of memory space and query processing time. It is shown that the set of Legendre chromaticity distribution moments (LCDM) provides a compact, fixed-length and computation effective representation of the colour contents of an image. Only a...

Informally, private information retrieval for k >= 1 databases (k-PIR) is an interactive scheme that enables a user to make access to (separated) k replicated copies of a database and privately retrieve any single bit out of the n bits of data stored in the database. In this model, “privacy” implies that the user retrieves the bit he is interested in but releases to each database nothing about ...

The information explosion in science has become a different problem, not the sheer amount per se, but the multiplicity and heterogeneity of massive sets of data sources. Relations mined from these heterogeneous sources, namely texts, database records, and ontologies have been mapped to Resource Description Framework (RDF) triples in an integrated database. The subject and object resources are e...

Private Information Retrieval (PIR), despite being well studied, is computationally costly and arduous to scale. We explore lower-cost relaxations of information-theoretic PIR, based on dummy queries, sparse vectors, and compositions with an anonymity system. We prove the security of each scheme using a flexible differentially private definition for private queries that can capture notions of i...

Over the last several decades, there have been numerous proposals for systems which can preserve the anonymity of the recipient of some data. Some have involved trusted third-parties or trusted hardware; others have been constructed on top of link-layer anonymity systems or mix-nets. In this paper, we evaluate a pseudonymous message system which takes the different approach of using Private Inf...

Private Information Retrieval (PIR), despite being well studied, is computationally costly and arduous to scale. We explore lower-cost relaxations of information-theoretic PIR, based on dummy queries, sparse vectors, and compositions with an anonymity system. We prove the security of each scheme using a flexible differentially private definition for private queries that can capture notions of i...

Private Information Retrieval (PIR), despite being well studied, is computationally costly and arduous to scale. We explore lower-cost relaxations of information-theoretic PIR, based on dummy queries, sparse vectors, and compositions with an anonymity system. We prove the security of each scheme using a flexible differentially private definition for private queries that can capture notions of i...

In this paper we describe our participation in the 2015 BioASQ challenge task on question answering (Phase A). Participants need to respond to the natural language questions in the format of documents, snippets, concepts and RDF triplets. In document retrieval, we build a generic retrieval model based on the sequential dependence model, Word Embedding and Ranking Model. In addition, from the vi...

A Private Information Retrieval (PIR) scheme is a protocol in which a user retrieves a record out of N from a replicated database, while hiding from the database which record has been retrieved, as long as the different replicas do not collude. A specially interesting sub-field of research, called singledatabase PIR, deals with the schemes that allow a user to retrieve privately an element of a...