1,280 research outputs found

    Using Simon's Algorithm to Attack Symmetric-Key Cryptographic Primitives

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    We present new connections between quantum information and the field of classical cryptography. In particular, we provide examples where Simon's algorithm can be used to show insecurity of commonly used cryptographic symmetric-key primitives. Specifically, these examples consist of a quantum distinguisher for the 3-round Feistel network and a forgery attack on CBC-MAC which forges a tag for a chosen-prefix message querying only other messages (of the same length). We assume that an adversary has quantum-oracle access to the respective classical primitives. Similar results have been achieved recently in independent work by Kaplan et al. Our findings shed new light on the post-quantum security of cryptographic schemes and underline that classical security proofs of cryptographic constructions need to be revisited in light of quantum attackers.Comment: 14 pages, 2 figures. v3: final polished version, more formal definitions adde

    Supersymmetric solutions of SU(2)-Fayet-Iliopoulos-gauged N=2,d=4 supergravity

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    We explore the construction of supersymmetric solutions of theories of N=2,d=4 supergravity with a SU(2) gauging and SU(2) Fayet-Iliopoulos terms. In these theories an SU(2) isometry subgroup of the Special Kahler manifold is gauged together with a SU(2) R-symmetry subgroup. We construct several solutions of the CP3 quadratic model directly in four dimensions and of the ST[2,6] model by dimensional reduction of the solutions found by Cariglia and Mac Conamhna in N=(1,0),d=6 supergravity with the same kind of gauging. In the CP3 model, we construct an AdS2xS2 solution which is only 1/8 BPS and an RxH3 solution that also preserves 1 of the 8 possible supersymmetries. We show how to use dimensional reduction as in the ungauged case to obtain RnxSm and also AdSnxSm-type solutions (with different radii) in - and 4 dimensions from the 6-dimensional AdS3xS3 solution.Comment: Latex 2e file, 37 pages, 1 figure. A paragraph on Fayet-Iliopoulos gaugings rewritten and minor typos corrected. Version to be published in Nuclear Physics

    A Schematic Framework to Assess Mini Hydro Potentials in the Italian Regional Energy and Environmental Plans

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    In compliance with EU legislation (Directive 2009/28/EC, that establishes for each Member State a target calculated according to the share of energy from renewable sources in its gross final consumption to 2020) and Italian regulatory framework (DM 15/03/12- Burden Sharing, that defines the regional objectives regarding renewable sources), each Italian Region must develop its own Regional Energy and Environmental Plan (PEAR). In order to promote the renewable energy sources (RES) production and to achieve a better energy efficiency use, the PEARS should propose to adopt a distributed multi generation (DMG) strategy. The main aim of this paper is a preliminary assessment of mini hydro potential and perspectives (P <1 MW) in Italian PEARS. Mini hydro is a mature and developed technology in Italy, and it represents a valiant opportunity for both local territories and the whole national system. Furthermore, thanks to its small size (low economic investment and environmental impact) and its versatility, it has the characteristics for a long-term development with direct industrial implications (i.e. energy cooperative and short supply chain). Specifically, the PEARS of four Regions were analysed, identifying the different information about mini hydro and comparing characteristics and potential. The results obtained are summarized in a schematic framework useful to draw a preliminary PEARS guideline that indicates strategies and policies, harmonizing public and private initiatives and structuring a local-scale economy through a mini hydro based DMG

    A GIS-based model to assess electric energy consumptions and usable renewable energy potential in Lazio region at municipality scale

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    The ongoing energy transition processes need a rapprochement between the places of energy production and consumption with the aim of creating innovative and integrated territorial models. Consequentially, models and strategies for increasing the use of local and renewable energy sources (RES) play a key rule for enhancing energy independence and sustainability of the considered areas. The main objective of this study is to analyse the energy system of the Lazio Region in Italy, comparing electricity consumptions and production from renewable sources at municipality scale. In order to estimate the electricity consumptions and the local production by RES, the main sectors of electricity consumption together with the potential of the available RES for the electricity production have been analysed. The obtained results pinpointed the main critical aspects of the Lazio region, that are mainly focalized in the city of Rome and in the most densely inhabited municipalities. Furthermore, research outputs provide an overall framework on the regional RES potential and allowed the formulation of proposals aimed at overcoming the identified criticalities and increasing the share of electricity production from renewables. Finally, the research approach could be replicated in other areas, providing a useful process for decision makers and stakeholders

    Energy use in residential buildings: Impact of building automation control systems on energy performance and flexibility

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    This work shows the results of a research activity aimed at characterizing the energy habits of Italian residential users. In detail, by the energy simulation of a buildings sample, the opportunity to implement a demand/response program (DR) has been investigated. Italian residential utilities are poorly electrified and flexible loads are low. The presence of an automation system is an essential requirement for participating in a DR program and, in addition, it can allow important reductions in energy consumption. In this work the characteristics of three control systems have been defined, based on the services incidence on energy consumptions along with a sensitivity analysis on some energy drivers. Using the procedure established by the European Standard EN 15232, the achievable energy and economic savings have been evaluated. Finally, a financial analysis of the investments has been carried out, considering also the incentives provided by the Italian regulations. The payback time is generally not very long: depending on the control system features it varies from 7 to 10 years; moreover, the automation system installation within dwellings is a relatively simple activity, which is characterized by a limited execution times and by an initial expenditure ranging in 1000 € to 4000 €, related to the three sample systems

    An overview on safety issues related to hydrogen and methane blend applications in domestic and industrial use

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    The share of electrical energy hailing from renewable sources in the European electricity mix is increasing. The match between renewable power supply and demand has become the greatest challenge to cope with. Gas infrastructure can accommodate large volumes of electricity converted into gas whenever this supply of renewable power is larger than the grid capacity or than the electricity demand. The Power-to-Gas (P2G) process chain could play a significant role in the future energy system. Renewable electric energy can be transformed into storable hydrogen via electrolysis and subsequent methanation. The aim of this paper is to provide an overview of the required technical adaptations of the most common devices for end users such as heating plants, CHP systems, home gas furnaces and cooking surfaces, wherever these are fuelled with methane and hydrogen blends in variable percentages by volume. Special attention will be given to issues related to essential safety standards, firstly comparing existing Italian and European regulations in this regard, and secondly highlighting the potential need for legislation to regulate the suitability of hydrogen methane blends. Finally, a list of foreseeable technical solutions will be provided and discussed thoroughly

    Why We Teach: Autobiographies of Traditionally and Alternatively Certified Pre-Service Social Studies Teachers

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    This study describes the analysis of the social studies autobiographies of 46 students compiled over a 15 month period. Two major questions were addressed: (1) what motivational patterns are revealed in these autobiographies and (2) what differences and similarities exist in the autobiographies of students seeking alternative and traditional certification. Both groups noted the influence of family and other significant adults, and the influence of social studies teachers, both K-12 and postsecondary, in their decisions to pursue social studies teaching careers. There were more similarities than differences between the two groups. The autobiographies echoed influences that are found in the literature, and reveal that active learning opportunities and inspiring teachers are important in motivating students to pursue careers in social studies education

    BPS black holes in a non-homogeneous deformation of the stu model of N=2N=2, D=4D=4 gauged supergravity

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    We consider a deformation of the well-known stu model of N=2N=2, D=4D=4 supergravity, characterized by a non-homogeneous special K\"{a}hler manifold, and by the smallest electric-magnetic duality Lie algebra consistent with its upliftability to five dimensions. We explicitly solve the BPS attractor equations and construct static supersymmetric black holes with radial symmetry, in the context of U(1)\text{U}(1) dyonic Fayet-Iliopoulos gauging, focussing on axion-free solutions. Due to non-homogeneity of the scalar manifold, the model evades the analysis recently given in the literature. The relevant physical properties of the resulting black hole solution are discussed.Comment: 26 pages, uses jheppub.st
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