Secure and efficient anonymization of distributed confidential databases

Let us consider the following situation: \(t\) entities (e.g., hospitals) hold different databases containing different records for the same type of confidential (e.g., medical) data. They want to deliver a protected version of this data to third parties (e.g., pharmaceutical researchers), preserving in some way both the utility and the privacy of the original data. This can be done by applying a statistical disclosure control (SDC) method. One possibility is that each entity protects its own database individually, but this strategy provides less utility and privacy than a collective strategy where the entities cooperate, by means of a distributed protocol, to produce a global protected dataset. In this paper, we investigate the problem of distributed protocols for SDC protection methods. We propose a simple, efficient and secure distributed protocol for the specific SDC method of rank shuffling. We run some experiments to evaluate the quality of this protocol and to compare the individual and collective strategies for solving the problem of protecting a distributed database. With respect to other distributed versions of SDC methods, the new protocol provides either more security or more efficiency, as we discuss through the paper.     

Metal Adsorption on Clays from Pyrite Contaminated Soil

A clayey soil contaminated with pyrite was treated with the addition of a base in laboratory experiments. The subsequent rise in pH is an efficient mechanism to retain the metals released by the sulfide weathering. Iron concentrations decrease as pH increases owing to the formation of secondary hydroxide phases, such as ferrihydrite. Aluminum and the aqueous divalent metals, such as Cu, Zn, Ni, Co, Cd, and Mn also decrease in concentration as pH increases. The fall in concentration can be accounted for by the formation of complexes on the surface of illite, which forms about 20 wt?% of the soil. Given the proportion of illite and the thickness of clayey soils in the Aznalcóllar region, the addition of a base such as lime or lime-containing flying ash could be an efficient remediation process. By contrast, the addition of more efficient exchangers such as zeolite continues to be recommended for sandy soils and gravels from the area with low clay contents.     

Orientation preserving mesh optimisation and preconditioning

A robust mesh optimisation method is presented that directly enforces the resulting deformation to be orientation preserving. Motivated by aspects from mathematical elasticity, the energy functional of the mesh deformation can be related to a stored‐energy functional of a hyperelastic material. Formulating the functional in the principal invariants of the deformation gradient allows fine‐grained control over the resulting deformation. Solution techniques for the arising nonconvex and highly nonlinear system are presented. As existing preconditioners are not sufficient, a partial differential equation–based preconditioner is developed.     

Combined Defect and Heterojunction Engineering in ZnTe/CoTe2@NC Sulfur Hosts Toward Robust Lithium–Sulfur Batteries

Lithium–sulfur batteries (LSBs) are feasible candidates for the next generation of energy storage devices, but the shuttle effect of lithium polysulfides (LiPSs) and the poor electrical conductivity of sulfur and lithium sulfides limit their application. Herein, a sulfur host based on nitrogen-doped carbon (NC) coated with small amount of a transition metal telluride (TMT) catalyst is proposed to overcome these limitations. The properties of the sulfur redox catalyst are tuned by adjusting the anion vacancy concentration and engineering a ZnTe/CoTe₂ heterostructures. Theoretical calculations and experimental data demonstrate that tellurium vacancies enhance the adsorption of LiPSs, while the formed TMT/TMT and TMT/C heterostructures as well as the overall architecture of the composite simultaneously provide high Li⁺ diffusion and fast electron transport. As a result, v-ZnTe/CoTe₂@NC/S sulfur cathodes show excellent initial capacities up to 1608 mA h g⁻¹ at 0.1C and stable cycling with an average capacity decay rate of 0.022% per cycle at 1C during 500 cycles. Even at a high sulfur loading of 5.4 mg cm^–2, a high capacity of 1273 mA h g⁻¹ at 0.1C is retained, and when reducing the electrolyte to 7.5 µL mg⁻¹, v-ZnTe/CoTe₂@NC/S still maintains a capacity of 890.8 mA h g⁻¹ after 100 cycles at 0.1C.     

RDSR-V. Reliable Dynamic Source Routing for video-streaming over mobile ad hoc networks

Mobile ad hoc networks (MANETs) are infrastructureless networks formed by wireless mobile devices with limited battery life. In MANETs for civilian applications, the network nodes may not belong to a single authority and they may not have a common goal. These MANETs are particularly vulnerable to selfish behavior, as some nodes may prefer saving resources to forward data. There are a few generic reputation-based systems for MANETs which could be used to enforce cooperation among nodes. However, we envision that the system performance can be highly improved by using cross-layer techniques that take into account the specific characteristics of each particular service. In this article, we propose a distributed and easy-to-implement routing mechanism based on reputation for the provision of MPEG-2 video-streaming services over MANETs. The main novelty that we introduce regarding the existent literature is that our proposal is service aware, that is to say, we consider the video-streaming service characteristics to develop a cross-layer design with the routing protocol. In addition, we do not introduce extra signaling overhead to monitor reputation because we use the standard video-streaming end-to-end signaling. Finally, simulation results show that our proposal clearly outperforms both standard Dynamic Source Routing (DSR) and OCEAN (a generic reputation-based mechanism).     

Automatic generation of basic behavior schemas from UML class diagrams

The specification of a software system must include all relevant static and dynamic aspects of the domain. Dynamic aspects are usually specified by means of a behavioral schema consisting of a set of system operations that the user may execute to update the system state. To be useful, such a set must be complete (i.e. through these operations, users should be able to modify the population of all elements in the class diagram) and executable (i.e. for each operation, there must exist a system state over which the operation can be successfully applied). A manual specification of these operations is an error-prone and time-consuming activity. Therefore, the aim of this paper is to present a strategy for the automatic generation of a basic behavior schema. Operations in the schema are drawn from the static aspects of the domain as defined in the UML class diagram and take into account possible dependencies among them to ensure the completeness and executability of the operations. We believe our approach is especially useful in a Model-Driven Development setting, where the full implementation of the system is derived from its specification. In this context, our approach facilitates the definition of the behavioral specification and ensures its quality obtaining, as a result, an improved code generation phase.     

Towards a model-driven approach for multiexperience AI-based user interfaces

Software and Systems Modeling - Software systems start to include other types of interfaces beyond the “traditional” Graphical-User Interfaces (GUIs). In particular, Conversational User...     

Hierarchical On-line Appearance-Based Tracking for 3D head pose,eyebrows, lips,eyelids and irises

In this paper, we propose an On-line Appearance-Based Tracker (OABT) for simultaneous tracking of 3D head pose, lips, eyebrows, eyelids and irises in monocular video sequences. In contrast to previously proposed tracking approaches, which deal with face and gaze tracking separately, our OABT can also be used for eyelid and iris tracking, as well as 3D head pose, lips and eyebrows facial actions tracking. Furthermore, our approach applies an on-line learning of changes in the appearance of the tracked target. Hence, the prior training of appearance models, which usually requires a large amount of labeled facial images, is avoided. Moreover, the proposed method is built upon a hierarchical combination of three OABTs, which are optimized using a Levenberg–Marquardt Algorithm (LMA) enhanced with line-search procedures. This, in turn, makes the proposed method robust to changes in lighting conditions, occlusions and translucent textures, as evidenced by our experiments. Finally, the proposed method achieves head and facial actions tracking in real-time.     

Economic model of a Cloud provider operating in a federated Cloud

Resource provisioning in Cloud providers is a challenge because of the high variability of load over time. On the one hand, the providers can serve most of the requests owning only a restricted amount of resources, but this forces to reject customers during peak hours. On the other hand, valley hours incur in under-utilization of the resources, which forces the providers to increase their prices to be profitable. Federation overcomes these limitations and allows providers to dynamically outsource resources to others in response to demand variations. Furthermore, it allows providers with underused resources to rent them to other providers. Both techniques make the provider getting more profit when used adequately. Federation of Cloud providers requires having a clear understanding of the consequences of each decision. In this paper, we present a characterization of providers operating in a federated Cloud which helps to choose the most convenient decision depending on the environment conditions. These include when to outsource to other providers, rent free resources to other providers (i.e., insourcing), or turn off unused nodes to save power. We characterize these decisions as a function of several parameters and implement a federated provider that uses this characterization to exploit federation. Finally, we evaluate the profitability of using these techniques using the data from a real provider.     

A Fair and Secure Cluster Formation Process for Ad Hoc Networks

An efficient approach for organizing large ad hoc networks is to divide the nodes into multiple clusters and designate, for each cluster, a clusterhead which is responsible for holding intercluster control information. The role of a clusterhead entails rights and duties. On the one hand, it has a dominant position in front of the others because it manages the connectivity and has access to other node’s sensitive information. But on the other hand, the clusterhead role also has some associated costs. Hence, in order to prevent malicious nodes from taking control of the group in a fraudulent way and avoid selfish attacks from suitable nodes, the clusterhead needs to be elected in a secure way. In this paper we present a novel solution that guarantees the clusterhead is elected in a cheat-proof manner.