5,464 research outputs found

    A quasilinear differential inclusion for viscous and rate-independent damage systems in non-smooth domains

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    This paper focuses on rate-independent damage in elastic bodies. Since the driving energy is nonconvex, solutions may have jumps as a function of time, and in this situation it is known that the classical concept of energetic solutions for rate-independent systems may fail to accurately describe the behavior of the system at jumps. Therefore we resort to the (by now well-established) vanishing viscosity approach to rate-independent modeling, and approximate the model by its viscous regularization. In fact, the analysis of the latter PDE system presents remarkable difficulties, due to its highly nonlinear character. We tackle it by combining a variational approach to a class of abstract doubly nonlinear evolution equations, with careful regularity estimates tailored to this specific system, relying on a q-Laplacian type gradient regularization of the damage variable. Hence for the viscous problem we conclude the existence of weak solutions, satisfying a suitable energy-dissipation inequality that is the starting point for the vanishing viscosity analysis. The latter leads to the notion of (weak) parameterized solution to our rate-independent system, which encompasses the influence of viscosity in the description of the jump regime

    Multipartite entanglement detection for hypergraph states

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    We study the entanglement properties of quantum hypergraph states of nn qubits, focusing on multipartite entanglement. We compute multipartite entanglement for hypergraph states with a single hyperedge of maximum cardinality, for hypergraph states endowed with all possible hyperedges of cardinality equal to n−1n-1 and for those hypergraph states with all possible hyperedges of cardinality greater than or equal to n−1n-1. We then find a lower bound to the multipartite entanglement of a generic quantum hypergraph state. We finally apply the multipartite entanglement results to the construction of entanglement witness operators, able to detect genuine multipartite entanglement in the neighbourhood of a given hypergraph state. We first build entanglement witnesses of the projective type, then propose a class of witnesses based on the stabilizer formalism, hence called stabilizer witnesses, able to reduce the experimental effort from an exponential to a linear growth in the number of local measurement settings with the number of qubits

    Experimental Detection of Quantum Channels

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    We demonstrate experimentally the possibility of efficiently detecting properties of quantum channels and quantum gates. The optimal detection scheme is first achieved for non entanglement breaking channels of the depolarizing form and is based on the generation and detection of polarized entangled photons. We then demonstrate channel detection for non separable maps by considering the CNOT gate and employing two-photon hyperentangled states.Comment: 8 pages, 9 figure

    Experimental generation of entanglement from classical correlations via non-unital local noise

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    We experimentally show how classical correlations can be turned into quantum entanglement, via the presence of non-unital local noise and the action of a CNOT gate. We first implement a simple two-qubit protocol in which entanglement production is not possible in the absence of local non-unital noise, while entanglement arises with the introduction of noise, and is proportional to the degree of noisiness. We then perform a more elaborate four-qubit experiment, by employing two hyperentangled photons initially carrying only classical correlations. We demonstrate a scheme where the entanglement is generated via local non-unital noise, with the advantage to be robust against local unitaries performed by an adversary.Comment: 8 pages, 4 figure

    Experimental and numerical analysis of a scaled dry-joint arch on moving supports

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    This paper aims to investigate the response of a scaled segmental dry-joint masonry arch to the settlement of one support. An experimental test and numerical simulations were performed by applying incremental vertical displacements at the right support up to collapse. The experimental test was carried out on a 1:10 small-scale model of the arch made of bi-component composite blocks with dry joints. Numerical simulations were performed using a finite element (FE) micro-modelling approach, where the arch was discretised as a set of very stiff voussoirs connected by nonlinear interfaces. Experimental and numerical results were compared in terms of displacement capacity and collapse mechanisms. The sensitivity of the numerical results to the interface stiffness was also evaluated.Peer ReviewedPostprint (author's final draft

    Psycho-relational well-being in women with sexual pain: a preliminary study

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    Female sexual pain is a complex multi-factorial condition. Most of the research has focused on underlying biomedical factors. Although psychological and relational factors have been studied as possible correlates, data are still controversial. The aim of the present study was to investigate psychological and relational well-being in women who complain of sexual pain. The hypothesis was that sexual pain is associated with worse scores

    EC-CENTRIC: An Energy- and Context-Centric Perspective on IoT Systems and Protocol Design

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    The radio transceiver of an IoT device is often where most of the energy is consumed. For this reason, most research so far has focused on low power circuit and energy efficient physical layer designs, with the goal of reducing the average energy per information bit required for communication. While these efforts are valuable per se, their actual effectiveness can be partially neutralized by ill-designed network, processing and resource management solutions, which can become a primary factor of performance degradation, in terms of throughput, responsiveness and energy efficiency. The objective of this paper is to describe an energy-centric and context-aware optimization framework that accounts for the energy impact of the fundamental functionalities of an IoT system and that proceeds along three main technical thrusts: 1) balancing signal-dependent processing techniques (compression and feature extraction) and communication tasks; 2) jointly designing channel access and routing protocols to maximize the network lifetime; 3) providing self-adaptability to different operating conditions through the adoption of suitable learning architectures and of flexible/reconfigurable algorithms and protocols. After discussing this framework, we present some preliminary results that validate the effectiveness of our proposed line of action, and show how the use of adaptive signal processing and channel access techniques allows an IoT network to dynamically tune lifetime for signal distortion, according to the requirements dictated by the application

    Organizational Factors Affecting Charitable Giving in the Environmental Nonprofit Context

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    Nonprofit organizations operating in the environmental protection and conservation sector face challenging fundraising issues in collecting from individual donors the money needed to accomplish their goals. The purpose of this study was to investigate which organizational factors can play a role in influencing the ability of these organizations to collect charitable contributions. By applying an extended version of the economic model of giving to a sample of 142 environmental nonprofits from the United States, the results of the regression analyses show that the following factors allow these organizations to attract more donations: devoting a high percentage of donations to programs, promoting the organization\u2019s image through fundraising activities, having a large amount of assets that ensures a sustainable financial structure, and providing online information that demonstrates how the organization has dealt with its mission. Moreover, the study reveals that providing high amounts of disclosure on the organization\u2019s website can have a conditional effect on fundraising expenses by boosting the positive effect of these expenses on donations. The results of this study contribute to the debate on the effectiveness of organizational factors in attracting funds from donors willing to support environmental nonprofits