1,986 research outputs found

    Quantum-enhanced reinforcement learning for finite-episode games with discrete state spaces

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    Quantum annealing algorithms belong to the class of metaheuristic tools, applicable for solving binary optimization problems. Hardware implementations of quantum annealing, such as the quantum annealing machines produced by D-Wave Systems, have been subject to multiple analyses in research, with the aim of characterizing the technology's usefulness for optimization and sampling tasks. Here, we present a way to partially embed both Monte Carlo policy iteration for finding an optimal policy on random observations, as well as how to embed (n) sub-optimal state-value functions for approximating an improved state-value function given a policy for finite horizon games with discrete state spaces on a D-Wave 2000Q quantum processing unit (QPU). We explain how both problems can be expressed as a quadratic unconstrained binary optimization (QUBO) problem, and show that quantum-enhanced Monte Carlo policy evaluation allows for finding equivalent or better state-value functions for a given policy with the same number episodes compared to a purely classical Monte Carlo algorithm. Additionally, we describe a quantum-classical policy learning algorithm. Our first and foremost aim is to explain how to represent and solve parts of these problems with the help of the QPU, and not to prove supremacy over every existing classical policy evaluation algorithm.Comment: 17 pages, 7 figure

    Top quark properties at the Tevatron

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    Precise determination of the top quark properties allows for stringent tests of the Standard Model. In this paper we report the latest results from the CDF and DØ Collaborations on a data sample of p¯p collisions at 1.96TeV collected at the Fermilab Tevatron up to an integrated luminosity of 4.8 fb−1

    A comparison between different treeline types shows contrasting responses to climate fluctuations

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    Treeline position is mainly determined by growth season temperature, but the response of treelines to climate warming is not uniform worldwide. We compared treeline structure, dynamics and thermal profile in nearby areas with different treeline type, species composition and bioclimatic conditions. We performed a detailed survey of different treeline types in three areas of Italian Alps and northern Apennines. Every tree individual was recorded along altitudinal transects from the closed forest to the species limit. Treeline structure and dynamics were described through altitudinal limits of tree height, density and age. Data were elaborated by principal components analysis. Temperature regime of the three sites was assessed from homogeneous historical climatic data. Treeline was different in the three areas for species composition, shape and dynamics. Both Alpine sites showed diffuse treeline, but only one showed advancing dynamics. Apennine treeline was abrupt and static, with higher temperature at the tree limit. Our study showed the variable dynamics of treelines within a relatively restricted area and the connection between treeline shape and dynamics. An important role is played by species composition, determined by bioclimatic and historical features. These factors should be taken into account when modelling future treeline dynamics at global scale

    Comparative energy and economic performance analysis of an electrochromic window and automated external venetian blind

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    Abstract A virtual test cell representing a portion of an office building was modeled in order to evaluate the energy balance and the economic convenience related to the use, as solar control devices, of a switchable electrochromic glazing system (EG) and of an automated external venetian blind system (VB). Furthermore, results were compared with a so-called base case (BC) of the glazed component, with no exterior solar shading. The virtual test cell is supposed located in Milan, Italy. The operation of both shading systems was set in order to minimize undesirable solar heat gains during cooling season and to maximize them during heating season and also in order to optimize the daylighting performance without having glare effect on the work plane. The energy balance of the selected systems was done considering the annual primary energy consumption for heating, cooling, lighting, shading system operation and the glazed systems' embodied energy annual quota. Finally, a further comparison in terms of economic convenience was done. Simulations were performed using EnergyPlus 7.0 dynamic simulation engine in conjunction with BESTenergy Graphic User Interface

    Renovation of an UNESCO Heritage Settlement in Southern Italy: ASHP and BIPV for a "Spread Hotel" Project☆

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    Abstract Many small historical settlements in Mediterranean areas have a great value in terms of architectural and cultural heritage. Therefore it happens that the socio–economic situation of many of these settlements is backward and depressed. A succesful way to develop these important environments is to implement tourism, a profitable and available economical resource. "Spread Hotel" or "Diffuse Hotel" or "Albergo Diffuso" is an innovative concept which aims to renovate decayed buildings situated in historical locations. New economical inputs are needed to revitalize these settlements and their social tissue. "Diffuse Hotel" concept is very diffused in Italy due to its rich historical heritage. The present paper displays a renovation project of a rural historical settlement into a "Spread Hotel". The site under analysis is located in Palazzolo Acreide, Sicily, Italy. The settlement strongly needed to be refurbished in order to provide habitability and to guarantee a proper level of comfort according to italian standards. The area is also listed in the UNESCO Heritage. The "Diffuse Hotel" at a national level is considered as an affordable and comfortable concept that enables the travellers to experiance Italy through a tipical, historical and comfortable hotel. The historical built enviroment preservation is strategic in Italy and can strongly support economical revitalization. European Community supports the development of "Spread Hotels" projects in order to improve economical capacity of depressed areas by financing refurbishment programs. In this contest the authors present how "Palazzolo Acreide" renovation project was done. In particular, the design strategy was to respect the local characteristics, improve thermal performance and HVAC systems and exploting the on site renewable energy. In fact, in the Mediterranean areas solar radiation is a incredible resource to provide energy to the buildings

    Glyco-gold nanoparticles: Synthesis and applications

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    Glyco-gold nanoparticles combine in a single entity the peculiar properties of gold nanoparticles with the biological activity of carbohydrates. The result is an exciting nanosystem, able to mimic the natural multivalent presentation of saccharide moieties and to exploit the peculiar optical properties of the metallic core. In this review, we present recent advances on glyco-gold nanoparticle applications in different biological fields, highlighting the key parameters which inspire the glyco nanoparticle design

    Acetal pH-sensitive linkers for glycol-protein conjugation

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