1,800,913 research outputs found

    Trade-off informed adaptive and robust real options water resources planning

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    Planning water resource systems is challenged primarily by two realities. First, uncertainty is inherent in the predictions of future supplies and demands due for example to hydrological variability and climate change. To build societal resilience water planners should seek to enhance the adaptability and robustness of water resource system interventions. Second, water resource developments typically involve competing interests which implies considering the trade-offs and synergies implied by the highest performing combinations of development options is useful. This work describes a real options based planning framework that generates adaptive and robust water system design alternatives able to consider and trade-off different goals. The framework can address different types of uncertainties and suggests the highest performing designs across multiple evaluation criteria, such as financial costs and water supply service performance metrics. Using a global city's water resource and supply system as a demonstration of the approach, we explore the trade-offs between a long-term water management plan's infrastructure services (service resilience, reliability, vulnerability) and its financial costs under supply and demand uncertainty. The set of trade-off solutions consist of different investment plans which are adaptive and robust to future changing conditions. Results show that the highest performing plans lower net present value (NPV) of needed investments by up to 18%, while maintaining similar performance across the other objectives. The real option value of delaying investments as much as possible approaches up to 14% of total NPV

    The Scalability-Efficiency/Maintainability-Portability Trade-off in Simulation Software Engineering: Examples and a Preliminary Systematic Literature Review

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    Large-scale simulations play a central role in science and the industry. Several challenges occur when building simulation software, because simulations require complex software developed in a dynamic construction process. That is why simulation software engineering (SSE) is emerging lately as a research focus. The dichotomous trade-off between scalability and efficiency (SE) on the one hand and maintainability and portability (MP) on the other hand is one of the core challenges. We report on the SE/MP trade-off in the context of an ongoing systematic literature review (SLR). After characterizing the issue of the SE/MP trade-off using two examples from our own research, we (1) review the 33 identified articles that assess the trade-off, (2) summarize the proposed solutions for the trade-off, and (3) discuss the findings for SSE and future work. Overall, we see evidence for the SE/MP trade-off and first solution approaches. However, a strong empirical foundation has yet to be established; general quantitative metrics and methods supporting software developers in addressing the trade-off have to be developed. We foresee considerable future work in SSE across scientific communities.Comment: 9 pages, 2 figures. Accepted for presentation at the Fourth International Workshop on Software Engineering for High Performance Computing in Computational Science and Engineering (SEHPCCSE 2016

    Evolving Phillips trade-off

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    We characterise the evolution of the U.S. unemployment-inflation trade-off since the late XIX century era via a Bayesian time-varying parameters structural VAR. The Great Inflation episode appears as historically unique along several dimensions. In particular, the shape of the ‘Phillips loop’–which is defined in terms of the impulse-response functions of inflation and unemployment’s deviations from equilibrium–was, during those years, clearly out of line with respect to the rest of the sample period for all structural innovations except money demand shocks. During the Great Depression, on the other hand, the Phillips trade-off did not exhibit any peculiar qualitative feature, so that, when seen through these lenses, the 1930s only stand out because of the sheer size of the macroeconomic fluctuation. The historical evolution of the Phillips trade-off exhibits virtually no connection with the evolution of the extent of trade openness of the U.S. economy. Although, by itself, this does not rule out a possible impact of globalisation on the slope of the trade-off in recent years, it clearly suggests that, historically, the evolution of the trade-off has been dominated by factors other than trade openness. JEL Classification: E30, E32Bayesian VARs, Globalisation, Great Depression, Great Inflation, identified VARs, Lucas Critique, Phillips trade-off, stochastic volatility, time-varying parameters

    Generalized remote state preparation: Trading cbits, qubits and ebits in quantum communication

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    We consider the problem of communicating quantum states by simultaneously making use of a noiseless classical channel, a noiseless quantum channel and shared entanglement. We specifically study the version of the problem in which the sender is given knowledge of the state to be communicated. In this setting, a trade-off arises between the three resources, some portions of which have been investigated previously in the contexts of the quantum-classical trade-off in data compression, remote state preparation and superdense coding of quantum states, each of which amounts to allowing just two out of these three resources. We present a formula for the triple resource trade-off that reduces its calculation to evaluating the data compression trade-off formula. In the process, we also construct protocols achieving all the optimal points. These turn out to be achievable by trade-off coding and suitable time-sharing between optimal protocols for cases involving two resources out of the three mentioned above.Comment: 15 pages, 2 figures, 1 tabl

    Evaluating the impact of the Alcohol Act on off-trade alcohol sales: a natural experiment in Scotland

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    <b>Background and aims</b> A ban on multi-buy discounts of off-trade alcohol was introduced as part of the Alcohol Act in Scotland in October 2011. The aim of this study was to assess the impact of this legislation on alcohol sales, which provide the best indicator of population consumption.<p></p> <b>Design Setting and Participants</b> Interrupted time-series regression was used to assess the impact of the Alcohol Act on alcohol sales among off-trade retailers in Scotland. Models accounted for underlying seasonal and secular trends and were adjusted for disposable income, alcohol prices and substitution effects. Data for off-trade retailers in England and Wales combined (EW) provided a control group.<p></p> <b>Measurements</b> Weekly data on the volume of pure alcohol sold by off-trade retailers in Scotland and EW between January 2009 and September 2012.<p></p> <b>Findings</b> The introduction of the legislation was associated with a 2.6% (95% CI -5.3 to 0.2%, P = 0.07) decrease in off-trade alcohol sales in Scotland, but not in EW (-0.5%, -4.6 to 3.9%, P = 0.83). A statistically significant reduction was observed in Scotland when EW sales were adjusted for in the analysis (-1.7%, -3.1 to -0.3%, P = 0.02). The decline in Scotland was driven by reduced off-trade sales of wine (-4.0%, -5.4 to -2.6%, P < 0.001) and pre-mixed beverages (-8.5%, -12.7 to -4.1%, P < 0.001). There were no associated changes in other drink types in Scotland, or in sales of any drink type in EW.<p></p> <b>Conclusions</b> The introduction of the Alcohol Act in Scotland in 2011 was associated with a decrease in total off-trade alcohol sales in Scotland, largely driven by reduced off-trade wine sales

    Multiple Observers Can Share the Nonlocality of Half of an Entangled Pair by Using Optimal Weak Measurements

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    We investigate the trade-off between information gain and disturbance for a class of weak von Neumann measurements on spin-12\frac{1}{2} particles, and derive the unusual measurement pointer state that saturates this trade-off. We then consider the fundamental question of sharing the non-locality of a single particle of an entangled pair among multiple observers, and demonstrate that by exploiting the information gain disturbance trade-off, one can obtain an arbitrarily long sequence of consecutive and independent violations of the CHSH-Bell inequality.Comment: 16 pages, 6 figures, PRL versio

    Sparsity-accuracy trade-off in MKL

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    We empirically investigate the best trade-off between sparse and uniformly-weighted multiple kernel learning (MKL) using the elastic-net regularization on real and simulated datasets. We find that the best trade-off parameter depends not only on the sparsity of the true kernel-weight spectrum but also on the linear dependence among kernels and the number of samples.Comment: 8pages, 2 figure

    Security Trade-offs in Ancilla-Free Quantum Bit Commitment in the Presence of Superselection Rules

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    Security trade-offs have been established for one-way bit commitment in quant-ph/0106019. We study this trade-off in two superselection settings. We show that for an `abelian' superselection rule (exemplified by particle conservation) the standard trade-off between sealing and binding properties still holds. For the non-abelian case (exemplified by angular momentum conservation) the security trade-off can be more subtle, which we illustrate by showing that if the bit-commitment is forced to be ancilla-free an asymptotically secure quantum bit commitment is possible.Comment: 7 pages Latex; v2 has 8 pages and additional references and clarifications, this paper is to appear in the New Journal of Physic
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