85 research outputs found
From LTL and Limit-Deterministic B\"uchi Automata to Deterministic Parity Automata
Controller synthesis for general linear temporal logic (LTL) objectives is a
challenging task. The standard approach involves translating the LTL objective
into a deterministic parity automaton (DPA) by means of the Safra-Piterman
construction. One of the challenges is the size of the DPA, which often grows
very fast in practice, and can reach double exponential size in the length of
the LTL formula. In this paper we describe a single exponential translation
from limit-deterministic B\"uchi automata (LDBA) to DPA, and show that it can
be concatenated with a recent efficient translation from LTL to LDBA to yield a
double exponential, \enquote{Safraless} LTL-to-DPA construction. We also report
on an implementation, a comparison with the SPOT library, and performance on
several sets of formulas, including instances from the 2016 SyntComp
competition
Reversible Metal-Semiconductor Transition of ssDNA-Decorated Single-Walled Carbon Nanotubes
A field effect transistor (FET) measurement of a SWNT shows a transition from
a metallic one to a p-type semiconductor after helical wrapping of DNA. Water
is found to be critical to activate this metal-semiconductor transition in the
SWNT-ssDNA hybrid. Raman spectroscopy confirms the same change in electrical
behavior. According to our ab initio calculations, a band gap can open up in a
metallic SWNT with wrapped ssDNA in the presence of water molecules due to
charge transfer.Comment: 13 pages, 6 figure
Dissociation of ssDNA - Single-Walled Carbon Nanotube Hybrids by Watson-Crick Base Pairing
The unwrapping event of ssDNA from the SWNT during the Watson-Crick base
paring is investigated through electrical and optical methods, and binding
energy calculations. While the ssDNA-metallic SWNT hybrid shows the p-type
semiconducting property, the hybridization product recovered metallic
properties. The gel electrophoresis directly verifies the result of wrapping
and unwrapping events which was also reflected to the Raman shifts. Our
molecular dynamics simulations and binding energy calculations provide
atomistic description for the pathway to this phenomenon. This nano-physical
phenomenon will open up a new approach for nano-bio sensing of specific
sequences with the advantages of efficient particle-based recognition, no
labeling, and direct electrical detection which can be easily realized into a
microfluidic chip format.Comment: 4 pages, 4 figure
Typology of seismic motion and seismic engineering design
The paper deals with the influence of the seismic motion typology on the structural response
and with engineering design under exceptional actions. Various aspects of seismic motion typology that lead
to exceptional actions on the structures are covered. The influence of near fault ground motions, the effect of
local site parameters and the magnification of the seismic action on short-period structures are among the parameters
identified as dominant for the structural response. The paper presents also a methodology for handling
uncertainty in engineering design, based on the mathematical framework of fuzzy analysis. Finally the
paper presents various applications of performance based design, which is viewed as a tool as a tool for the
analysis of structural behaviour under extreme seismic events. The influence of connection behaviour on the
structural response is studied, and applications of the capacity design methodology and of the direct displacement
design approach for the evaluation of reinforce concrete structures are presented
Predicting carbon dioxide and energy fluxes across global FLUXNET sites with regression algorithms
Gianluca Tramontana was supported by the GEOCARBON EU FP7 project (GA 283080). Dario Papale, Martin Jung and Markus Reichstein acknowledge funding from the EU FP7 project GEOCARBON (grant agreement no. 283080) and the EU H2020 BACI project (grant agreement no. 640176). Gustau Camps-Valls wants to acknowledge the support by an ERC Consolidator Grant with grant agreement 647423 (SEDAL). Kazuhito Ichii was supported by Environment Research and Technology Development Funds (2-1401) from the Ministry of the Environment of Japan and the JAXA Global Change Observation Mission (GCOM) project (no. 115). Christopher R. Schwalm was supported by National Aeronautics and Space Administration (NASA) grants nos. NNX12AP74G, NNX10AG01A, and NNX11AO08A. M. Altaf Arain thanks the support of Natural Sciences and Engineering Research Council (NSREC) of Canada. Penelope Serrano Ortiz was partially supported by the GEISpain project (CGL2014-52838-C2-1-R) funded by the Spanish Ministry of Economy and Competitiveness and the European Union ERDF funds. Sebastian Wolf acknowledges support from a Marie Curie International Outgoing Fellowship (European Commission, grant 300083). The FLUXCOM initiative is coordinated by Martin Jung, Max Planck Institute for Biogeochemistry (Jena, Germany). This work used eddy-covariance data acquired by the FLUXNET community and in particular by the following networks: AmeriFlux (US Department of Energy, Biological and Environmental Research, Terrestrial Carbon Program (DE-FG02-04ER63917 and DE-FG02-04ER63911)), AfriFlux, AsiaFlux, CarboAfrica, CarboEuropeIP, CarboItaly, CarboMont, ChinaFlux, FluxnetCanada (supported by CFCAS, NSERC, BIOCAP, Environment Canada, and NRCan), GreenGrass, KoFlux, LBA, NECC, OzFlux, TCOS-Siberia, USCCC. We acknowledge the financial support to the eddy-covariance data harmonization provided by CarboEuropeIP, FAO-GTOS-TCO, iLEAPS, the Max Planck Institute for Biogeochemistry, the National Science Foundation, the University of Tuscia and the US Department of Energy, and the databasing and technical support from Berkeley Water Center, Lawrence Berkeley National Laboratory, Microsoft Research eScience, Oak Ridge National Laboratory, the University of California - Berkeley, and the University of Virginia.Spatio-temporal fields of land–atmosphere fluxes derived from data-driven models can complement simulations by process-based land surface models. While a number of strategies for empirical models with eddy-covariance flux data have been applied, a systematic intercomparison of these methods has been missing so far. In this study, we performed a cross-validation experiment for predicting carbon dioxide, latent heat, sensible heat and net radiation fluxes across different ecosystem types with 11 machine learning (ML) methods from four different classes (kernel methods, neural networks, tree methods, and regression splines). We applied two complementary setups: (1) 8-day average fluxes based on remotely sensed data and (2) daily mean fluxes based on meteorological data and a mean seasonal cycle of remotely sensed variables. The patterns of predictions from different ML and experimental setups were highly consistent. There were systematic differences in performance among the fluxes, with the following ascending order: net ecosystem exchange (R2  0.6), gross primary production (R2> 0.7), latent heat (R2 > 0.7), sensible heat (R2 > 0.7), and net radiation (R2 > 0.8). The ML methods predicted the across-site variability and the mean seasonal cycle of the observed fluxes very well (R2 > 0.7), while the 8-day deviations from the mean seasonal cycle were not well predicted (R2 < 0.5). Fluxes were better predicted at forested and temperate climate sites than at sites in extreme climates or less represented by training data (e.g., the tropics). The evaluated large ensemble of ML-based models will be the basis of new global flux products.European Union (EU)
GA 283080
283080
640176European Research Council (ERC)
647423Ministry of the Environment, Japan
2-1401JAXA Global Change Observation Mission (GCOM) project
115National Aeronautics & Space Administration (NASA)
NNX12AP74G
NNX10AG01A
NNX11AO08ANatural Sciences and Engineering Research Council of CanadaGEISpain project - Spanish Ministry of Economy and Competitiveness
CGL2014-52838-C2-1-REuropean Commission Joint Research Centre
300083United States Department of Energy (DOE)
DE-FG02-04ER63917
DE-FG02-04ER63911FAO-GTOS-TCOiLEAPSMax Planck Institute for BiogeochemistryNational Science Foundation (NSF)University of Tusci
The effect of social interactions in the primary life cycle of motion pictures
We model the consumption life cycle of theater attendance for single movies
by taking into account the size of the targeted group and the effect of social
interactions. We provide an analytical solution of such model, which we
contrast with empirical data from the film industry obtaining good agreement
with the diverse types of behaviors empirically found. The model grants a
quantitative measure of the valorization of this cul- tural good based on the
relative values of the coupling between agents who have watched the movie and
those who have not. This represents a measurement of the observed quality of
the good that is extracted solely from its dynamics, independently of critics
reviews.Comment: 9 Pages, 3 figure
Omega-Regular Objectives in Model-Free Reinforcement Learning
We provide the first solution for model-free reinforcement learning of ω-regular objectives for Markov decision processes (MDPs). We present a constructive reduction from the almost-sure satisfaction of ω-regular bjectives to an almost-sure reachability problem, and extend this technique to learning how to control an unknown model so that the chance of satisfying the objective is maximized. We compile ω-regular properties into limit-deterministic B¨uchi automata instead of the traditional Rabin automata; this choice sidesteps difficulties that have marred previous proposals. Our approach allows us to apply model-free, off-the-shelf reinforcement learning algorithms to compute optimal strategies from the observations of the MDP. We present an experimental evaluation of our technique on benchmark learning problems
Active microrheology and simultaneous visualization of sheared phospholipid monolayers
Two-dimensional films of surface-active agents—from phospholipids and proteins to nanoparticles and colloids—stabilize fluid interfaces, which are essential to the science, technology and engineering of everyday life. The 2D nature of interfaces present unique challenges and opportunities: coupling between the 2D films and the bulk fluids complicates the measurement of surface dynamic properties, but allows the interfacial microstructure to be directly visualized during deformation. Here we present a novel technique that combines active microrheology with fluorescence microscopy to visualize fluid interfaces as they deform under applied stress, allowing structure and rheology to be correlated on the micron-scale in monolayer films. We show that even simple, single-component lipid monolayers can exhibit viscoelasticity, history dependence, a yield stress and hours-long time scales for elastic recoil and aging. Simultaneous visualization of the monolayer under stress shows that the rich dynamical response results from the cooperative dynamics and deformation of liquid-crystalline domains and their boundaries
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Evaluating the Benefits of Aphasia Intervention Delivered in Virtual Reality: Results of a Quasi-Randomised Study
Introduction
This study evaluated an intervention for people with aphasia delivered in a novel virtual reality platform called EVA Park. EVA Park contains a number of functional and fantastic locations and allows for interactive communication between multiple users. Twenty people with aphasia had 5 weeks’ intervention, during which they received daily language stimulation sessions in EVA Park from a support worker. The study employed a quasi randomised design, which compared a group that received immediate intervention with a waitlist control group. Outcome measures explored the effects of intervention on communication and language skills, communicative confidence and feelings of social isolation. Compliance with the intervention was also explored through attrition and usage data.
Results
There was excellent compliance with the intervention, with no participants lost to follow up and most (18/20) receiving at least 88% of the intended treatment dose. Intervention brought about significant gains on a measure of functional communication. Gains were achieved by both groups of participants, once intervention was received, and were well maintained. Changes on the measures of communicative confidence and feelings of social isolation were not achieved. Results are discussed with reference to previous aphasia therapy findings
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