3,218 research outputs found

    Vector plotting as an indication of the approach to flutter

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    A binary flexure-torsion analysis was made to check theoretically a method for predicting flutter which depends on plotting vectorially the amplitudes of response relative to the exciting force and extracting the relevant damping rate. The results of this calculation are given in graphs both of the vector plots themselves and of the estimated damping rate against forward speed. The estimated damping rates are compared with calculated values. The method has the advantage that in a flight flutter test damping can be estimated from continuous excitation records: the method is an extension of the Kennedy and Pancu technique used in ground resonance testing

    Quantum Fully Homomorphic Encryption With Verification

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    Fully-homomorphic encryption (FHE) enables computation on encrypted data while maintaining secrecy. Recent research has shown that such schemes exist even for quantum computation. Given the numerous applications of classical FHE (zero-knowledge proofs, secure two-party computation, obfuscation, etc.) it is reasonable to hope that quantum FHE (or QFHE) will lead to many new results in the quantum setting. However, a crucial ingredient in almost all applications of FHE is circuit verification. Classically, verification is performed by checking a transcript of the homomorphic computation. Quantumly, this strategy is impossible due to no-cloning. This leads to an important open question: can quantum computations be delegated and verified in a non-interactive manner? In this work, we answer this question in the affirmative, by constructing a scheme for QFHE with verification (vQFHE). Our scheme provides authenticated encryption, and enables arbitrary polynomial-time quantum computations without the need of interaction between client and server. Verification is almost entirely classical; for computations that start and end with classical states, it is completely classical. As a first application, we show how to construct quantum one-time programs from classical one-time programs and vQFHE.Comment: 30 page

    EPR Steering Inequalities from Entropic Uncertainty Relations

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    We use entropic uncertainty relations to formulate inequalities that witness Einstein-Podolsky-Rosen (EPR) steering correlations in diverse quantum systems. We then use these inequalities to formulate symmetric EPR-steering inequalities using the mutual information. We explore the differing natures of the correlations captured by one-way and symmetric steering inequalities, and examine the possibility of exclusive one-way steerability in two-qubit states. Furthermore, we show that steering inequalities can be extended to generalized positive operator valued measures (POVMs), and we also derive hybrid-steering inequalities between alternate degrees of freedom.Comment: 10 pages, 2 figure

    Quality of life in patients with intermittent claudication

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    © 2017, The Author(s). Background: Intermittent claudication (IC) is a common condition that causes pain in the lower limbs when walking and has been shown to severely impact the quality of life (QoL) of patients. The QoL is therefore often regarded as an important measure in clinical trials investigating intermittent claudication. To date, no consensus exits on the type of life questionnaire to be used. This review aims to examine the QoL questionnaires used in trials investigating peripheral arterial disease (PAD). Material and methods: A systematic review of randomised clinical trials including a primary analysis of QoL via questionnaire was performed. Trials involving patients with diagnosed PAD were included (either clinically or by questionnaire). Any trial which had QoL as the primary outcome data was included with no limit being placed on the type of questionnaire used. Results: The search yielded a total of 1845 articles of which 31 were deemed appropriate for inclusion in the review. In total, 14 different QoL questionnaires were used across 31 studies. Of the questionnaires 24.06% were missing at least one domain when reported in the results of the study. Mean standard deviation varied widely based on the domain reported, particularly within the SF36. Discussion: Despite previous recommendations for Europewide standardisation of quality of life assessment, to date no such tool exists. This review demonstrated that a number of different questionnaires remain in use, that their completion is often inadequate and that further evidence-based guidelines on QoL assessment are required to guide future research

    Architecture and Systemics - in Praise of Roughness

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    Architecture is a complex idea in its own right. In architectural culture, systemic references are not new. Design theories, in Europe as well as in USA, have often referred to many concepts more or less strictly linked to Systemics and to scientific domains such as Information theories and Cybernetics. Quite often, such references have been a mere metaphorical suggestion or, as in the field of “rational” design and process engineering, they mostly have heavy functional overtones. Such is the idea of “performance”, whose original definition was meant as an industrial design tool pursuing optimization, linking together the users’ needs and the requirements an artifact must possess to satisfy those needs. But, as we know, “bottom up” emergence processes have nothing to do with “top down” design strategies for optimization. Nevertheless, the idea of performance conveys the meaning of a strong influence intercurring between two entities, one of them on the “giving” and the other one on the “taking” sides, both of them interacting through feedback. For this reason, I believe the idea of performance should not be discarded lightheartedly. Rather, a “softer” notion of performance, linked to the realm of social perception and attachment to places, should be brought to thorough definition. It might be useful to find a more productive, non-metaphorical use of systemic references to understand and (then) to design - or to redevelop - human settlements

    The role of electric vehicles in decarbonising Australia's road transport sector: modelling ambitious scenarios

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    Transitioning to net-zero greenhouse gas (GHG) emissions by 2050 is becoming increasingly urgent, requiring accelerated efforts to decarbonise all economic sectors, including transport, a growing emissions source. A transition to battery electric vehicles (BEV) would accelerate the decarbonisation of road transport and provide other benefits. But in Australia, BEV uptake has been negligible, and the scale and pace required to reach net-zero emissions by 2050 has not been addressed to date. This study applies a national-scale integrated macroeconomic model (iSDG-Australia) to project Australia's future road transport demand, vehicle mix, energy consumption and GHG emissions by 2050. It models five scenarios incorporating different levels of economic and population growth, vehicle longevity, ambitions for BEV uptake, fleet renewal, forced phase-out of fossil-fuelled vehicles and shifts to renewable electricity. Scenario projections are benchmarked on their zero-emission vehicle mix, fuel and electricity consumption, GHG emissions, and broader social and economic impacts. We conclude the scale and pace of change must be transformational rather than transitional, requiring urgent policy action. An ambitious and rapid transition to 100% BEVs in new vehicle sales, accelerated fleet renewal, and a shift to renewable electricity generation could achieve a net-zero outcome for Australia's road transport sector by 2050

    A complete genome sequence ofLactobacillus helveticus R0052, a commercial probiotic strain

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    Lactobacillus helveticus R0052 is a commercially available strain that is widely used in probiotic preparations. The genome sequence consisted of 2,129,425 bases. Comparative analysis showed that it was unique among L. helveticus strains in that it contained genes encoding mucus-binding proteins similar to those found in Lactobacillus acidophilus

    Unforgeable Quantum Encryption

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    We study the problem of encrypting and authenticating quantum data in the presence of adversaries making adaptive chosen plaintext and chosen ciphertext queries. Classically, security games use string copying and comparison to detect adversarial cheating in such scenarios. Quantumly, this approach would violate no-cloning. We develop new techniques to overcome this problem: we use entanglement to detect cheating, and rely on recent results for characterizing quantum encryption schemes. We give definitions for (i.) ciphertext unforgeability , (ii.) indistinguishability under adaptive chosen-ciphertext attack, and (iii.) authenticated encryption. The restriction of each definition to the classical setting is at least as strong as the corresponding classical notion: (i) implies INT-CTXT, (ii) implies IND-CCA2, and (iii) implies AE. All of our new notions also imply QIND-CPA privacy. Combining one-time authentication and classical pseudorandomness, we construct schemes for each of these new quantum security notions, and provide several separation examples. Along the way, we also give a new definition of one-time quantum authentication which, unlike all previous approaches, authenticates ciphertexts rather than plaintexts.Comment: 22+2 pages, 1 figure. v3: error in the definition of QIND-CCA2 fixed, some proofs related to QIND-CCA2 clarifie
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