Vol. 69, n° 1-2, January-February 2014
Content available on Springerlink

Guest editors
Maryline Laurent, Télécom SudParis, France
Sara Foresti, Università degli Studi di Milano, Italy
Heng Xu, Pennsylviana State University, USA

Foreword

Maryline Laurent, Sara Foresti, Heng Xu

Privacy query rewriting algorithm instrumented by a privacy-aware access control model

Said Oulmakhzoune¹, Nora Cuppens-Boulahia¹, Frédéric Cuppens¹, Stéphane Morucci², Mahmoud Barhamgi³ and Djamal Benslimane³

(1) Institut Mines-Telecom/Telecom Bretagne, France
(2) SWID, Cesson-Sevigne, France
(3) Lyon 1 University, Villeurbanne, France

Abstract In this paper, we present an approach to instrument a Simple Protocol And RDF Query Language query rewriting algorithm enforcing privacy preferences. The term instrument is used to mean supplying appropriate constraints. We show how to design a real and effective instrumentation process of a rewriting algorithm using an existing privacy-aware access control model like PrivOrBAC. We take into account various dimensions of privacy preferences through the concepts of consent, accuracy, purpose, and recipient. We implement and evaluate our process of privacy enforcement based on a healthcare scenario.

Keywords Privacy-aware – PrivOrBAC – RDF – SPARQL – Rewriting algorithm

PriMa: a comprehensive approach to privacy protection in social network sites

Anna C. Squicciarini^{1, 3}, Federica Paci² and Smitha Sundareswaran¹  

(1) The Pennsylvania State University, USA
(2) University of Trento, Trento, Italy
(3) University Park, USA

Abstract With social networks (SNs) allowing their users to host large amounts of personal data on their platforms, privacy protection mechanisms are becoming increasingly important. The current privacy protection mechanisms offered by SNs mostly enforce access control policies based on users’ privacy settings. The task of setting privacy preferences may be tedious and confusing for the average user, who has hundreds of connections (e.g., acquaintances, colleagues, friends, etc.) and maintains an extensive profile on his main SN. Hence, users often end up with policies that do not sufficiently protect their personal information, thus facilitating potential privacy breaches and information misuse. In this paper, we propose PriMa (Privacy Manager), a privacy protection mechanism that supports semiautomated generation of access rules for users’ profile information, filling the gap between the privacy management needs of SN users and the existing SNs’ privacy protection mechanisms. PriMa access rules are generated using a multicriteria algorithm, so as to account for an extensive set of criteria to be considered when dealing with access control in SN sites. The resulting rules are simple yet powerful specifications, indicating the adequate level of protection for each user, and are dynamically adapted to the ever-changing requirements of the users’ preferences and SN configuration. We have implemented PriMa on a Drupal platform and as a third-party Facebook application. We have evaluated the performance of the PriMa application with respect to access rule generation.

Keywords Privacy – Social networks – Access control

Improving user content privacy on social networks using rights management systems

A survey on addressing privacy together with quality of context for context management in the Internet of Things

Sophie Chabridon¹, Romain Laborde², Thierry Desprats², Arnaud Oglaza², Pierrick Marie² and Samer Machara Marquez¹

(1) Télécom SudParis, France
(2) Université de Toulouse, France

Abstract Making the Internet of Things (IoT) a reality will contribute to extend the context-aware ability of numerous sensitive applications. We can foresee that the context of users will include not only their own spatio-temporal conditions but also those of the things situated in their ambient environment and at the same time, thanks to the IoT, those that are located in other remote spaces. Consequently, next-generation context managers have to interact with the IoT underlying technologies and must, even more than before, address both privacy and quality of context (QoC) requirements. In this article, we show that the notions of privacy and QoC are intimately related and sometimes contradictory and survey the recent works addressing them. Current solutions usually consider only one notion, and very few of them started to bridge privacy and QoC. We identify some of the remaining challenges that next-generation context managers have to deal with to favour users’ acceptability by providing both the optimal QoC level and the appropriate privacy protection.

Keywords Internet of Things – Context management – Privacy – Quality of context

On the uniqueness of Web browsing history patterns

Lukasz Olejnik¹ , Claude Castelluccia¹ and Artur Janc²  

(1) Inria Grenoble, France
(2) Google Inc., Mountain View, USA

Abstract We present the results of the first large-scale study of the uniqueness of Web browsing histories, gathered from a total of 368,284 Internet users who visited a history detection demonstration website. Our results show that for a majority of users (69 %), the browsing history is unique and that users for whom we could detect at least four visited websites were uniquely identified by their histories in 97 % of cases. We observe a significant rate of stability in browser history fingerprints: for repeat visitors, 38 % of fingerprints are identical over time, and differing ones were correlated with original history contents, indicating static browsing preferences (for history subvectors of size 50). We report a striking result that it is enough to test for a small number of pages in order to both enumerate users’ interests and perform an efficient and unique behavioral fingerprint; we show that testing 50 Web pages is enough to fingerprint 42 % of users in our database, increasing to 70 % with 500 Web pages.

Keywords Privacy – Web history – Fingerprinting

Privacy concerns in assisted living technologies

Vaibhav Garg¹ , L. Jean Camp¹ , Lesa Lorenzen-Huber¹ , Kalpana Shankar² and Kay Connelly¹  

(1) Indiana University Bloomington, USA
(2) University College Dublin, Ireland

Open topics

Video viewing: do auditory salient events capture visual attention?

Antoine Coutrot, Nathalie Guyader, Gelu Ionescu and Alice Caplier

Gipsa Laboratory, Saint Martin D’Heres, France

Abstract We assess whether salient auditory events contained in soundtracks modify eye movements when exploring videos. In a previous study, we found that, on average, nonspatial sound contained in video soundtracks impacts on eye movements. This result indicates that sound could play a leading part in visual attention models to predict eye movements. In this research, we go further and test whether the effect of sound on eye movements is stronger just after salient auditory events. To automatically spot salient auditory events, we used two auditory saliency models: the discrete energy separation algorithm and the energy model. Both models provide a saliency time curve, based on the fusion of several elementary audio features. The most salient auditory events were extracted by thresholding these curves. We examined some eye movement parameters just after these events rather than on all the video frames. We showed that the effect of sound on eye movements (variability between eye positions, saccade amplitude, and fixation duration) was not stronger after salient auditory events than on average over entire videos. Thus, we suggest that sound could impact on visual exploration not only after salient events but in a more global way.

Keywords Saliency – Eye movements – Sound Videos – Attention Multimodality – Audiovisual

An efficient channelizer tree for portable software defined radios

Fred Harris¹ , Elettra Venosa¹, Xiaofei Chen¹ and Chris Dick²  

(1) San Diego State University, USA
(2) Xilinx Corp, USA

Abstract Power consumption is one of the most critical issues in the portable software-defined radio devices. A software radio receiver has the need to downconvert, bandwidth limit, and downsample a single narrowband channel from a span of frequencies in the Nyquist zone collected by the input analog to digital converter. In this paper, we present two techniques that perform the receiver function more efficiently than the standard Gray chip architecture formed by its direct digital synthesizer (DDS), and two stages of downsampling with a cascade integrator comb (CIC) filter and a pair of half-band filters. We compare the workload of this conventional architecture to two new architectures by applying them to the task of extracting a single, 30 kHz wide, channel from a 30 MHz band sampled at 90 MHz. One proposed structure replaces the CIC filter with a 10-stage cascade of 2-to-1 downsampling half-band filters with successively narrower transition bandwidths. In the second proposed structure, the DDS is moved to the output of the filtering stages which perform a sequence of 2-to-1 downsampling operations in half-band filters that perform incidental spectral translation by aliasing. We enlarge the set of half-band filter that reside at 0 and fs/2, to also include the Hilbert transform half-band filters residing at ±fs/4. At every stage in the cascade, the selected band resides in one of the four half-band filters. The 2-to-1 downsampling with that filter reduces the bandwidth and aliases the desired center through a sequence of known center frequencies. The desired channel is recovered from the output of the final stage by a complex heterodyne applied (at the low output rate) to obtain the desired spectral shift to base band. The paper provides a detailed workload analysis of the proposed structure along with simulation results that prove its effectiveness.

Keywords Polyphase filter bank – Down converter channelizer – Software defined radio

Human perception-based distributed architecture for scalable video conferencing services: theoretical models and performance

Tien Anh Le and Hang Nguyen  

Télécom SudParis, France

Abstract This research work proposes a human perception-based distributed architecture for the multiparty video conferencing services. The new architecture can effectively reduce the unnecessary traffic of the multilayer video streams on the overlay network. Rich theoretical models of the three different architectures: the proposed perception-based distributed architecture, the conventional centralized architecture, and perception-based centralized architecture have been constructed by using queuing theory to reflect the traffic generated, transmitted, and processed by the three architectures. The performance has been considered in different aspects from the total waiting time to the required service rates. Together, the modeling tools, the analysis, and the numerical results help to answer the common concern about advantages and disadvantages of the centralized and distributed architectures. Overall, the proposed human perception-based distributed architecture can maintain a smaller total waiting time with a much smaller requirement of service rate in comparison with the conventional centralized architecture and perception-based centralized architecture.

Keywords Waiting time – End-to-end delay – Architecture analysis – Video conference – Service architecture – Distributed architecture – Centralized architecture Scalable video coding – Application layer multicast

Microcell prediction model based on support vector machine algorithm

Vladimir Slavkovic, Aleksandar Neskovic and Natasa Neskovic

University of Belgrade, Serbia

Abstract A new microcell prediction model for mobile radio environment is presented in this paper. The popular support vector machine algorithm is used as an optimizing tool to build a model. In order to validate the model quality, extensive electric field strength measurements were carried out in the city of Belgrade, for two different test transmitter locations. The analysis of the model has shown that proposed model is fast, accurate (on the order of the local mean measurements uncertainty), reliable, and suitable for computer implementation.

Keywords Microcell – Radio propagation – Prediction model – Support Vector – Machine algorithm