Search results for "key"

On the Cryptanalysis of Two Cryptographic Algorithms That Utilize Chaotic Neural Networks

2015

This paper deals with the security and efficiency issues of two cipher algorithms which utilize the principles of Chaotic Neural Networks (CNNs). The two algorithms that we consider are (1) the CNN-Hash, which is a one-way hash function based on the Piece-Wise Linear Chaotic Map (PWLCM) and the One-Way Coupled Map Lattice (OCML), and (2) the Delayed CNN-Based Encryption (DCBE), which is an encryption algorithm based on the delayed CNN. Although both of these cipher algorithms have their own salient characteristics, our analysis shows that, unfortunately, the CNN-Hash is not secure because it is neither Second-Preimage resistant nor collision resistant. Indeed, one can find a collision with …

Canonical Retina-to-Cortex Vision Model Ready for Automatic Differentiation

2020

Canonical vision models of the retina-to-V1 cortex pathway consist of cascades of several Linear+Nonlinear layers. In this setting, parameter tuning is the key to obtain a sensible behavior when putting all these multiple layers to work together. Conventional tuning of these neural models very much depends on the explicit computation of the derivatives of the response with regard to the parameters. And, in general, this is not an easy task. Automatic differentiation is a tool developed by the deep learning community to solve similar problems without the need of explicit computation of the analytic derivatives. Therefore, implementations of canonical visual neuroscience models that are ready…

Evaluation of changes in space control due to passing behavior in elite soccer using Voronoi-cells

2015

A soccer player’s ability to make an “effective” pass in a play situation is considered one of the key skills characterizing successful performance in elite soccer.

A Logical Key Hierarchy Based approach to preserve content privacy in Decentralized Online Social Networks

2020

Distributed Online Social Networks (DOSNs) have been proposed to shift the control over user data from a unique entity, the online social network provider, to the users of the DOSN themselves. In this paper we focus on the problem of preserving the privacy of the contents shared to large groups of users. In general, content privacy is enforced by encrypting the content, having only authorized parties being able to decrypt it. When efficiency has to be taken into account, new solutions have to be devised that: i) minimize the re-encryption of the contents published in a group when the composition of the group changes; and, ii) enable a fast distribution of the cryptographic keys to all the m…

An ultrathin suspended hydrophobic porous membrane for high-efficiency water desalination

2017

Abstract An ultrathin highly fluorinated porous membrane was designed for a large production of desalted water at very low energy consumption. Imprinting water droplets were used through a low thermally conductive tetra-fluoroethylene (TFE)/2,2,4-trifluoro-5-tri-fluorometoxy-1,3-dioxol (TIT) (HYFLON AD 60) solution and the generated porous nanofilm was suspended onto a polyethersulfone (PES) honeycomb texture. The very tiny fluorinated thickness together with a large number of small-shaped pores provided the membrane for enhanced anti-wetting surface properties, extremely reduced resistance to water vapor transfer and outstanding thermal efficiency. Fine materials structure-transport relati…

Epistemic and didactic values of the demonstrative process in different cultures: a case study in Geometry with Chinese and Italian students

2011

Electric vehicles and psychology

2021

The popularity of electric vehicles is evidenced by the broad range of manufacturers presenting new models of plug-in hybrid and battery vehicles. However, the success of the revolution or, rather, the rebirth of electric vehicles, is hanging by a thread, as it lacks the involvement of a large number of users, and many psychological mechanisms hinder it. What are users’ true feelings about this new world of vehicles? Are people ready for the fifth level of automation, i.e., fully automatic driving and the absence of the driving position? The purpose of this paper is to present and discuss the psychological aspects that influence the adoption of electric vehicles. Topics such as the chicken …

The photovoltaic growth in the European Union requires stronger RES support

2016

Since the adoption of the EU Directive, 2001/77/EC, the production of electricity from renewable energy sources has progressed. Apart from the indicative target proposed by the Directive, actually no other tools of policy monitoring exist. To fill this gap, we propose a dynamic method able to capture this multidimensional phenomenon, providing an assessment tool to measure the technical efficiency performances of EU countries in the photovoltaic sector (1996–2010). Results show how technical efficiencies of countries are, from one hand, due to problems belonging to the economic and political contexts in which they operate, on the other hand driven by specific political support schemes adopt…

Origins of the outperformance of venture backed initial public offerings : a French study

2010

In this thesis, we analyze the contractual relationship between private equity investors and entrepreneurs/managers of small and medium sized firms. More specifically, we focus on the real contribution of these financial intermediaries to the Initial Public Offering (IPO) performance of financed firms. While considering venture capitalists’ involvement in the governance of financed firms as the main explaining factor, we use the Corporate Governance theory as the relevant theoretical framework. Thus, we firstly point out the agency theory perspective and secondly the resource and knowledge based view perspective to examine the determinants of venture capitalists’ involvement and the impact …

Survey sampling for functionnal data : building asymptotic confidence bands and considering auxiliary information

2011

When collections of functional data are too large to be exhaustively observed, survey sampling techniques provide an effective way to estimate global quantities such as the population mean function, without being obligated to store all the data. In this thesis, we propose a Horvitz–Thompson estimator of the mean trajectory, and with additional assumptions on the sampling design, we state a functional Central Limit Theorem and deduce asymptotic confidence bands. For a fixed sample size, we show that stratified sampling can greatly improve the estimation compared to simple random sampling. In addition, we extend Neyman’s rule of optimal allocation to the functional context. Taking into accoun…