Trust-based security for the OLSR routing protocol

International audienceThe trust is always present implicitly in the protocols based on cooperation, in particular, between the entities involved in routing operations in Ad hoc networks. Indeed, as the wireless range of such nodes is limited, the nodes mutually cooperate with their neighbors in order to extend the remote nodes and the entire network. In our work, we are interested by trust as security solution for OLSR protocol. This approach fits particularly with characteristics of ad hoc networks. Moreover, the explicit trust management allows entities to reason with and about trust, and to take decisions regarding other entities. In this paper, we detail the techniques and the contributions in trust-based security in OLSR. We present trust-based analysis of the OLSR protocol using trust specification language, and we show how trust-based reasoning can allow each node to evaluate the behavior of the other nodes. After the detection of misbehaving nodes, we propose solutions of prevention and countermeasures to resolve the situations of inconsistency, and counter the malicious nodes. We demonstrate the effectiveness of our solution taking different simulated attacks scenarios. Our approach brings few modifications and is still compatible with the bare OLSR

A Decoupled 3D Facial Shape Model by Adversarial Training

Data-driven generative 3D face models are used to compactly encode facial shape data into meaningful parametric representations. A desirable property of these models is their ability to effectively decouple natural sources of variation, in particular identity and expression. While factorized representations have been proposed for that purpose, they are still limited in the variability they can capture and may present modeling artifacts when applied to tasks such as expression transfer. In this work, we explore a new direction with Generative Adversarial Networks and show that they contribute to better face modeling performances, especially in decoupling natural factors, while also achieving more diverse samples. To train the model we introduce a novel architecture that combines a 3D generator with a 2D discriminator that leverages conventional CNNs, where the two components are bridged by a geometry mapping layer. We further present a training scheme, based on auxiliary classifiers, to explicitly disentangle identity and expression attributes. Through quantitative and qualitative results on standard face datasets, we illustrate the benefits of our model and demonstrate that it outperforms competing state of the art methods in terms of decoupling and diversity.Comment: camera-ready version for ICCV'1

İbn Haldun’un gözünden Arap Baharı

The “Arab state” has also gone through phases, the five stages of the state life cycle as described by Ibn Khaldun, and it has also known many transformations. How can we analyze these political and social transformations and how are they interacting with each other from a Khaldunian perspective? How can we understand this current particular phase between the fall of the “Arab state”, as we’ve known it until now, and the rise of a “new” one in the light of Ibn Khaldun’s theory? A new phase characterized by ethnic conflicts that have taken a more apparent and obvious form in the aftermath of the Arab Spring. What are possible avenues to get rid of despotism and violence? The present paper is an attempt to answer these questions applying Ibn Khaldun’s theoretical framework to the current events and context of the Arab world.“Arap devleti” de İbn Haldun’un betimlediği gibi devlet hayat döngüsünün beş aşamasından geçmiştir. Ayrıca birçok dönüşüme de tanık olmuştur. Bu bağlamda siyasi ve toplumsal dönüşümleri ve birbirleriyle olan etkileşimleri nasıl analiz edebiliriz? Şu zamana kadar bildiğimiz kadarıyla “Arap devletinin” çöküşü ile “yeni” olanın yükselişi arasında kalan bu mevcut özel aşamayı İbn Haldun’un teorisi ışığında nasıl anlayabiliriz? Bu yeni aşama, Arap Baharı sonrasında daha aşikâr bir hal almış olan etnik çatışmalarla nitelendirilmektedir. Despotizm ve şiddetten kurtulmak için olası çıkış yolları nelerdir? Bu makalede bu sorulara İbn Haldun’un mevcut olaylar ve Arap dünyası bağlamına ilişkin teorik çerçevesi uygulanarak cevap verme çabası bulunmaktadır

High Temperature Characterization of Ge2Sb2Te5Thin Films for Phase Change Memory Applications

The recent proliferation of portable communication devices or data storage equipment is strongly related to the development of memory technology. Non-volatile semiconductor solid-state memories are needed for high-capacity storage media, high-speed operation and low power consumption, with stringent requirements of retention and endurance. Phase change memory (PCM) is currently seen as one of the most promising candidates for a future storage-class memory with the potential to be close to dynamic random-access memory (DRAM) in speed but with much longer retention times and as dense as flash memory. PCM devices utilize chalcogenide materials (most commonly Ge2Sb2Te5 or GST) that can be switched rapidly and reversibly between amorphous and crystalline phases with orders of magnitude difference in electrical resistivity. Since PCM devices operate at elevated (current-induced) temperatures and are significantly impacted by thermoelectric effects it is very important to determine the high temperature material properties of GST. Resistivity, carrier mobility, and carrier concentration in semiconducting materials are three key parameters indispensable for device modeling. In this work two measurement setups for high temperature thin film characterizations were developed, a Seebeck setup and a Hall setup. The Seebeck coefficient measurement setup is fully automated and uses resistive and inductive heaters to control the temperature gradient and can reach temperatures up to ~650 °C. The Hall measurement setup, developed based on the van der Paw method for characterization of semiconducting thin films, can measure thin film samples of a wide resistivity range from room temperature to ~500 °C. The resistivity, carrier concentration, and Hall carrier mobility are calculated from I-V measurements and the constant magnetic field applied in ‘up’ and ‘down’ directions. Measurement results on GST thin films with different thicknesses revealed interesting correlations between S-T and ρ-T characteristics and showed that GST behaves as a unipolar p-type semiconducting material from room temperature up to melting. The thermoelectric properties of the GST films were also correlated to the average grain sizes obtained from in-situ XRD measurements during crystallization. These studies show that the activation energy of carriers in mixed phase amorphous-fcc GST is a linear function of the Peltier coefficient. From these results and the ρ-T characteristics, the expected Seebeck coefficient of single crystal fcc GST is obtained. Using the experimental results for resistivity and Seebeck coefficient, together with a phase separation model, the temperature-dependent thermal conductivity of the mixed phase GST is extracted

MARINE: Man-in-the-middle attack resistant trust model IN connEcted vehicles

Vehicular Ad-hoc NETwork (VANET), a novel technology holds a paramount importance within the transportation domain due to its abilities to increase traffic efficiency and safety. Connected vehicles propagate sensitive information which must be shared with the neighbors in a secure environment. However, VANET may also include dishonest nodes such as Man-in-the-Middle (MiTM) attackers aiming to distribute and share malicious content with the vehicles, thus polluting the network with compromised information. In this regard, establishing trust among connected vehicles can increase security as every participating vehicle will generate and propagate authentic, accurate and trusted content within the network. In this paper, we propose a novel trust model, namely, Man-in-the-middle Attack Resistance trust model IN connEcted vehicles (MARINE), which identifies dishonest nodes performing MiTM attacks in an efficient way as well as revokes their credentials. Every node running MARINE system first establishes trust for the sender by performing multi-dimensional plausibility checks. Once the receiver verifies the trustworthiness of the sender, the received data is then evaluated both directly and indirectly. Extensive simulations are carried out to evaluate the performance and accuracy of MARINE rigorously across three MiTM attacker models and the bench-marked trust model. Simulation results show that for a network containing 35% MiTM attackers, MARINE outperforms the state of the art trust model by 15%, 18%, and 17% improvements in precision, recall and F-score, respectively.N/A

Global Dialogue Among Religions: An Islamic Perspective

The author raises questions about some aspects of the role of the theologian in a global world. He points out that the issues that theology faced in the past do not always directly connect with today’s issues. In the past, a Muslim theologian was considered an expert in theology, law and Sufism. But many definitive categories from the past seem antiquated in today’s complicated post-modern, globalizing world. We must now formulate our discourse in such a way as to be meaningful within our respective communities, but also within a larger pluralistic audience. Dialogue facilitates the process of distinguishing between the essential and the contingent. It can purify us of cultural ideology or imperialist religiosity. The Focolare offers a model for this wide-open dialogue, especially where tradition seems to conflict with innovation