3,656 research outputs found

    Parsing as Reduction

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    We reduce phrase-representation parsing to dependency parsing. Our reduction is grounded on a new intermediate representation, "head-ordered dependency trees", shown to be isomorphic to constituent trees. By encoding order information in the dependency labels, we show that any off-the-shelf, trainable dependency parser can be used to produce constituents. When this parser is non-projective, we can perform discontinuous parsing in a very natural manner. Despite the simplicity of our approach, experiments show that the resulting parsers are on par with strong baselines, such as the Berkeley parser for English and the best single system in the SPMRL-2014 shared task. Results are particularly striking for discontinuous parsing of German, where we surpass the current state of the art by a wide margin

    Parsing as reduction

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    We reduce phrase-representation parsing to dependency parsing. Our reduction is grounded on a new intermediate representation, “head-ordered dependency trees,” shown to be isomorphic to constituent trees. By encoding order information in the dependency labels, we show that any off-the-shelf, trainable dependency parser can be used to produce constituents. When this parser is non-projective, we can perform discontinuous parsing in a very natural manner. Despite the simplicity of our approach, experiments show that the resulting parsers are on par with strong baselines, such as the Berkeley parser for English and the best single system in the SPMRL-2014 shared task. Results are particularly striking for discontinuous parsing of German, where we surpass the current state of the art by a wide margin.Ministerio de Ciencia e Innovación | Ref. TIN2010-18552-C03-01Xunta de Galicia | Ref. R2014/029Xunta de Galicia | Ref. R2014/034Fundação para a Ciência e a Tecnologia | Ref. UID/EEA/50008/2013Fundação para a Ciência e a Tecnologia | Ref. PTDC/EEI-SII/2312/201

    Study of the performance of TBM in the excavation of granite rock masses of the north of Portugal using the Qtbm system

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    O sistema QTBM é uma metodologia empírica para a previsão dos rendimentos esperados na escavação de túneis com tuneladoras TBM, nomeadamente, as velocidades de penetração (PR) e de avanço (AR). Neste trabalho, esta metodologia é aplicada a uma base de dados geotécnica coligida durante as obras de construção de uma obra subterrânea hidroeléctrica na zona Norte de Portugal, com o objectivo de avaliar a adequabilidade de utilização de TBM na escavação de túneis em maciços graníticos típicos dessa região. Esta base de dados continha 1230 determinações de vários dos parâmetros necessários. Para os parâmetros em falta foram estabelecidos intervalos de confiança e realizadas análises de sensibilidade à sua variação. Deste estudo verificou-se que o maciço em questão apresenta boas características para ser escavado com recurso a tuneladora já que são expectáveis rendimentos bastante aceitáveis.The QTBM system is an empirical methodology for the performance prediction in tunnels excavated with TBM, namely the penetration and advance rates. In this work this methodology is applied to a database collected during the construction of a hydroelectric underground work built in the North of Portugal to evaluate the adequacy of using TBM in the excavation of tunnels in granite rock masses typical from that region. This database contained 1230 determinations of several parameters. For the ones missing, confidence intervals were set and sensitivity analysis was carried to evaluate the impact to their variation. From this study it was concluded that the analysed rock mass presents good characteristics to be excavated using TBM since the expected performance is rather acceptable

    Bidirectional DC-DC Converter with High Voltage Gain for the Charge/Discharge Control of Storage Systems

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    Trabalho apresentado em 10th Electric Power Quality and Supply Reliability Conference, 29-31 de agosto, Tallin, EstóniaThis paper presents a study of a bidirectional dc-dc converter with high voltage gain to regulate the charge and discharge of electrochemical storage systems. The converter is characterized by quadratic voltage gain characteristics in both directions. In this context it can be used to regulate a dc interface between the storage system and a dc/ac converter connected to the electrical grid. It will be analysed the converter in ideal and non-ideal conditions. A control system to regulate the output voltages and currents are also proposed. Simulation results are presented in order to validate the control system associated to the converter for the charge/discharge of the storage system.N/

    A SRM for a PV Powered Water Pumping System Based on a Multilevel Converter and DC/DC Dual Output Converter

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    Trabalho apresentado em 7th International Conference on Smart and Sustainable Technologies - Splitech 2022, 5-8 julho 2022, Bol, CroatiaThis paper focuses on a proposal for a system based on a photovoltaic (PV) supply for a powered water pumping. The system consists in a switched reluctance machine (SRM) controlled by a multilevel converter and fed by PV panels associated to a DC/DC converter. The multilevel power converter proposed to control the SRM was designed to minimize the switches and to support the balance of the two input capacitors. The DC/DC converter consists in a hybrid solution that merges a Buck- Boost converter with a Sepic converter. They use a topology solution in which the input current presents a reduced ripple and only requires one switch. This DC/DC converter is also characterized by a dual output to adapt to the multilevel converter. The control system and a maximum power point tracking (MPPT) algorithm are also presented. The operation of this system will be verified by tests that are done by computer simulations.N/

    Study, design and development of a new add-on function for the FRICTORQ® - Friction Test Instrument

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    The assessment of handle properties is of utmost importance in materials in our everyday life. There is a wide range of materials there are used in contact with the human skin, which may cause several unpleasant skin reactions. The FRICTORQ® is a laboratory equipment developed by the authors to measure the friction coefficient in fabrics, to enable a quantitative assessment of touch/handle, in order to predict the comfort behaviour of 2D/3D structures when used or touched by humans. In a further development, the FRICTORQ® was redesigned to accommodate a new testing kit function to determine the friction coefficient of fabrics in a liquid environment. This new design will be explained and the results obtained while testing different swimwear fabrics and hospital garments will be also presented and discussed

    Testing System for PV Grid-Connected Power Condition Systems with Support for Ancillary Services

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    Funding Information: This work was supported by national funds through FCT—Fundação para a Ciência e a Tecnologia with reference UID/CEC/50021/2020 and UID/EEA/00066/2020. Publisher Copyright: © 2023 by the authors.Due to the high spread of photovoltaic (PV) systems in the low voltage distribution grids there is a substantial number of requirements for the connection of these systems. Therefore, several tests should be performed before the integration of the PV systems into the grid. Moreover, new requirements have been established that are most likely to be implemented in the near future. To provide these tests and verify if PV systems are in accordance with requirements and recommendations, a testing setup for the PV systems was developed. This testing system consists of a controllable power source prepared to receive energy and to inject it into the grid. In fact, that system imposes a controllable voltage, in amplitude and frequency, to the PV system to simulate the perturbations of the grid. Since the system under test must inject energy in accordance with the standards’ specifications, then the controllable power source that emulates the grid must receive that energy. Moreover, it should also be prepared for PV systems that are able to provide ancillary services, including new ones that support imbalanced networks. A fast and robust control system will be used for this controllable power source. Several experimental tests from the developed prototype are presented.publishersversionpublishe

    Soil stabilisation using alkaline activation of fly ash for self-compacting rammed earth construction

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    This paper studies the effectiveness of alkaline activation of low-calcium fly ash on the improvement of residual granitic soils to be used on rammed-earth construction. Different liquid:solid ratios, alkali concentrations and Na2O : ash ratios were tested. Effect of calcium hidroxide, sodium chloride and concrete superplasticiser is also reported. Compressive strength up to 7 days at 60ºC was determined. Results show that, in terms of mechanical strength, there is an optimum value for the activator:solids ratio and the alkali concentration, and that a decrease in the Na2O:ash ratio results in strength increase. No improvement was observed with the sodium chloride or the superplasticiser, while the calcium produced only a short term increase in strength. SEM/EDS analysis were used to analyse microstructural development, showing that strength is fairly related to the Si:Al and Na:Si ratios

    Shear behaviour of rammed earth walls repaired by means of grouting

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    Southern Portugal presents a rich heritage constituted by several constructions made from unstabilised rammed earth (URE), which are threatened by several factors, ranging from lack of conservation to a non-negligible seismic hazard. These threatens are enhanced by the fact that little is known about the shear behaviour of URE constructions. The preservation of this heritage requires definitely the development of this knowledge and, in addition, the development of adequate intervention solutions. This paper presents an experimental program where the shear behaviour of URE is assessed by means of diagonal compression tests on representative wallet-specimens. Furthermore, the use of mud grouts in repairing cracks was also assessed. The results showed that the shear behaviour of URE depends on the binding capacity promoted by the clay fraction and on the friction and interlocking promoted by the coarse aggregates. The repair by injection was shown to promote satisfactory shear strength recovery of the specimens, but was less effective in recovering the initial shear stiffness.Fundação para a Ciência e a Tecnologia (FCT

    Big data warehouse framework for smart revenue management

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    Revenue Management’s most cited definitions is probably “to sell the right accommodation to the right customer, at the right time and the right price, with optimal satisfaction for customers and hoteliers”. Smart Revenue Management (SRM) is a project, which aims the development of smart automatic techniques for an efficient optimization of occupancy and rates of hotel accommodations, commonly referred to, as revenue management. One of the objectives of this project is to demonstrate that the collection of Big Data, followed by an appropriate assembly of functionalities, will make possible to generate a Data Warehouse necessary to produce high quality business intelligence and analytics. This will be achieved through the collection of data extracted from a variety of sources, including from the web. This paper proposes a three stage framework to develop the Big Data Warehouse for the SRM. Namely, the compilation of all available information, in the present case, it was focus only the extraction of information from the web by a web crawler – raw data. The storing of that raw data in a primary NoSQL database, and from that data the conception of a set of functionalities, rules, principles and semantics to select, combine and store in a secondary relational database the meaningful information for the Revenue Management (Big Data Warehouse). The last stage will be the principal focus of the paper. In this context, clues will also be giving how to compile information for Business Intelligence. All these functionalities contribute to a holistic framework that, in the future, will make it possible to anticipate customers and competitor’s behavior, fundamental elements to fulfill the Revenue Managemen
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