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Mesh Generation for Atmospheric Boundary Layer Simulation in Wind Farm Design and Management

Procedia engineering 2015年 124卷 239-251页

作者： A. Gargallo-Peiró M. Avila H. Owen L. Prieto A. Folch Dpt. Computer Applications in Science and Engineering Barcelona Supercomputing Center C/ Gran Capitán 2-4 08034 Barcelona Spain Energy Resource Dpt. Iberdrola Renovables Energía C/ Tomás Redondo 1 28033 Madrid Spain

We propose a new automatic procedure to generate hybrid meshes to simulate turbulent flows for wind farm design and management. In particular, numerical modeling of wind farms involves a RANS simulation of the Atmospheric Boundary Layer (ABL) flow and modeling the turbines using the actuator disc theory. Therefore, the generated meshes have to fulfill several geometrical requirements to answer to the different modeling features. They must: capture the topography features that can influence the wind flow; have a boundary layer close to the terrain to resolve the ABL; be conformally adapted to the disc (turbine) to simulate the turbine effects on the wind flow; be adapted around the disc to capture the wake effect; and present a smooth mesh size transition around the disc to conform the mesh size of the ABL mesh, in which the turbines are immersed. We highlight that the mesh generation procedure is fully automatic once given the mesh size, a topography description, the wind inflow direction, a list of turbine insertion points, and the turbine models. To illustrate the applicability of the proposed procedure, we present two wind farm cases: an offshore wind farm mesh where we illustrate the computed wind deficit, and an onshore farm assimilating real topography data.

关键词： hybrid meshes hexahedral meshes quadrilateral meshes mesh optimization wind farm wind turbine atmospheric boundary layer

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MULTIFRAME BLIND DECONVOLUTION OF PASSIVE MILLIMETER WAVE IMAGES USING VARIATIONAL DIRICHLET BLUR KERNEL ESTIMATION

MULTIFRAME BLIND DECONVOLUTION OF PASSIVE MILLIMETER WAVE IM...

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IEEE International Conference on Image Processing

作者： Javier Mateos Antonio Lopez Miguel Vega Rafael Molina Aggelos K. Katsaggelos Dpt. de Ciencias de la Computacion e I. A. Univ. de Granada Dpt. de Lenguajes y Sistemas Informaticos Univ. de Granada Dpt. of Electrical Engineering and Computer Science Northwestern University

ISBN: (纸本)9781467399623

Passive Millimeter Wave Images currently used to detect hidden threats suffer from low resolution, blur, and a very low signal-to-noise-ratio. These shortcomings render threat detection, both visual and automatic, very challenging. Furthermore, due to the presence of very severe noise, most of the blind image restoration methods fail to recover the system blurring kernel from a single image. In this paper we propose a robust Bayesian multiframe blind image deconvolution method that approximates the posterior distribution of the blur by a Dirichlet distribution. We show that this approach naturally incorporates the non-negativity and normalization constraints for the blur and cope well with the image noise. The performance of the proposed method is tested on both synthetic and real images.

关键词： Passive millimeter wave imaging Blind image deconvolution Variational Dirichlet images deconvolution millimetre wave imaging Seeds blind deconvolution waves waveforms Posterior distribution image noise Blind multiframe

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UlsaNA: Universal language semantic analyzer 12

UlsaNA: Universal language semantic analyzer

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12th International Conference on Recent Advances in Natural Language Processing, RANLP 2019

作者： Pražák, Ondřej Konopík, Miloslav NTIS Faculty of Applied Sciences University of West Bohemia Technická 8 Plzeň306 14 Czech Republic Dpt. of Computer Science and Engineering Faculty of Applied Sciences University of West Bohemia Technická 8 Plzeň306 14 Czech Republic

ISBN: (纸本)9789544520557

We present a live cross-lingual system capable of producing shallow semantic annotations of natural language sentences for 51 languages at this time. The domain of the input sentences is in principle unconstrained. The system uses single training data (in English) for all the languages. The resulting semantic annotations are therefore consistent across different languages. We use CoNLL Semantic Role Labeling training data and Universal dependencies as the basis for the system. The system is publicly available and supports processing data in batches;therefore, it can be easily used by the community for research tasks. © 2019 Association for Computational Linguistics (ACL). All rights reserved.

关键词： Deep learning

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A power saving scheduling algorithm for multiple MSSs in large-scale IEEE 802.16e environments 10

A power saving scheduling algorithm for multiple MSSs in lar...

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6th International Wireless Communications and Mobile Computing Conference, IWCMC 2010

作者： Huang, Huai-Sheng Chen, Yu-Jen Wu, Shih-Lin Chen, Jen-Jee Dpt. of Information Management Chang Gung University Kweishan Taoyuan Taiwan Dpt. of Computer Science and Imformation Engineering Chang Gung University Kweishan Taoyuan Taiwan Department of Computer Science National Chiao Tung University Hsinchu Taiwan

ISBN: (纸本)9781450300629

Power Saving Class (PSC) is an essential issue on IEEE 802.16-2009. In previous research, many algorithms had been proposed to reduce the consumption of power, but most of them only considered multiple connections in a Mobile Subscriber Station (MSS);in fact, it does not fit in with the situation of real world. On the contrary, others proposed algorithms considering the situation of multiple MSSs with multiple connections;nevertheless, it is difficult to increase the amount of MSSs. In this paper, we propose an efficient algorithm, which refers to both categories and avoids state transitions. When packet size is much smaller or delay bound is more loosening, the result shows that our scheduling algorithm can serve almost double multiple MSSs with multiple connections and still maintain high sleep ratio for energy efficiency. Copyright © 2010 ACM.

关键词： Scheduling algorithms

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Long-term and spatial evaluation of the integrated performance of a window-shade system in an open space office located in Rome 2

Long-term and spatial evaluation of the integrated performan...

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Building Simulation Applications, BSA 2015 - 2nd IBPSA-Italy Conference

作者： Atzeri, Anna Maria Cappelletti, Francesca Tzempelikos, Athanasios Gasparella, Andrea Free University of Bolzano/Bozen Faculty of Science and Technology Italy University IUAV of Venezia Dpt. of Design and Planning in Complex Environments Venezia Italy Purdue University School of Civil Engineering Ray W. Herrick Labs West LafayetteIN United States

ISBN: (纸本)9788860460745

The building façades, as a boundary between external and internal environments, play a central role in energy reduction and suitable comfort conditions maintenance. Their evaluation requires an integrated assessment approach, focused on occupants' thermal and visual comfort, in time and space, as well as on maximizing daylight and achieving energy saving goals. In this paper, dynamic simulation is used to evaluate the integrated performance of different fenestration systems in an open space office located in Rome. The illuminating analysis has been performed using DIVA, and the results, processed by means of a Matlab code, have been used as an input for Energy Plus thermal and energy analysis. Then, the Energy Plus outputs have been post processed to calculate the solar radiation influence on occupants thermal comfort. Some new metrics have been introduced in such a way that it is possible to assess the comfort performance with comprehensive indicators. © 2015 by Bozen-Bolzano University Press Free University of Bozen-Bolzano All rights reserved.

关键词： Energy conservation

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Subdividing triangular and quadrilateral meshes in parallel to approximate curved geometries

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Procedia engineering 2017年 203卷 310-322页

作者： A. Gargallo-Peiró G. Houzeaux X. Roca Computer Applications in Science and Engineering Dpt. Barcelona Supercomputing Center-Centro Nacional de Supercomputación C/ Jordi Girona 29 Barcelona 08034 Spain

A parallel distributed approach to refine a mesh while preserving the curvature of a target geometry is presented. Our approach starts by generating a coarse linear mesh of the computational domain. Second, the former coarse mesh is curved to match the curvature of the target geometry. Then, the curved mesh is partitioned and the subdomain meshes are sent to the slaves. Finally, the curved elements are uniformly subdivided in parallel targeting the geometry approximated by the curved mesh. The result is a distributed finer linear mesh featuring improved geometric accuracy. The key ingredient of our implementation is to approximate the target geometry as a linear mesh equipped with an elemental field corresponding to an element-wise polynomial geometry representation. Thus, the distribution of the curved geometry is equivalent to partitioning the linear mesh and sending the subdomain meshes and the elemental fields to the slaves. The main application of the obtained finer linear mesh is to compute in parallel steady state flow solutions on real topographies. The qualitative results show that for 2D and 3D steady state flow solutions, on real and synthetic topographies, our parallel subdivision approach mitigates the artificial artifacts that might appear with standard straight-sided subdivision methods. We also check the parallel performance of the implementation by performing a weak scalability test in 2D.

关键词： Mesh subdivision Mesh multiplication Parallel mesh generation Parallel computing High-order mesh

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Maximin Fairness-profit Tradeoff in Project Budget Allocation

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Procedia computer science 2016年 100卷 313-320页

作者： Maurizio Naldi Gaia Nicosia Andrea Pacifici Ulrich Pferschy Dpt. of Computer Science and Civil Engineering University of Rome Tor Vergata Rome Italy Dipartimento di Ingegneria Universita’ Roma Tre Rome Italy Department of Statistics and Operations Research University of Graz Graz Austria

Companies typically select those projects that maximize their profit as the primary criterion, within the limited budget at their disposal. This criterion may lead to some company departments getting an exceedingly large share of the overall budget and induce a negative perception of unfairness among the less favourite ones. We investigate how profit optimization can be sought after while achieving the desired level of fairness at the same time. Adopting a maximin approach to fairness and using an Integer Linear Programming solver, we show that a linear trade-off is possible, since fairness and profit exhibit a nearly perfect linear anticorrelation. Fairness can be improved by even a relatively small reduction of profit, especially in large companies (i.e., managing a large number of projects).

关键词： Budget allocation Multi-project management Project Portfolio Fairness

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Miniaturized multi-band stopband filter using circular split ring resonator and null gap separations between all parallel lines

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Progress In Electromagnetics Research C 2020年 106卷 137-150页

作者： Ahmed, Badiaa Ait Aghzout, Otman Naghar, Azzeddin Alejos, Ana V. Dpt. of Computer Science Engineering SIGL-Lab. ENSA University of Abdelmalek Essaadi Tétouan Morocco BSA-Innovation LAB Radio Frequency Systems RFS Lannion France Dpt. of Signal Theory and communications University of Vigo Pontevedra Spain

This paper presents a new multi-band stopband filter loaded by a shorted metamaterial circuit. Firstly, two filters loaded by stubs and open ring resonators (ORRs) are studied and compared. The ORRs allow more effects in terms of miniaturization by a shifting toward low frequencies and rejection bandwidth (57.34%). To improve the filter efficiency, coupled split ring resonators (SRRs) are used. The final filter is characterized by a miniaturized size of 18.840 mm2, wide rejection bandwidth, high selectivity level, and multiple resonances over S, C, X, and Ku bands. L-C equivalent circuit model filter and other characteristics are investigated. A prototype of the filter with coupled SRRs has been fabricated and measured. Good matching among EM-simulation, equivalent circuit modelling, and measured results are achieved. © 2020, Electromagnetics Academy. All rights reserved.

关键词： Circuit simulation

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Fake News, Disinformation, and Deepfakes: Leveraging Distributed Ledger Technologies and Blockchain to Combat Digital Deception and Counterfeit Reality

arXiv

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arXiv 2019年

作者： Fraga-Lamas, Paula Fernández-Caramés, Tiago M. Dpt. of Computer Engineering Centro de investigación CITIC Faculty of Computer Science Universidade da Coruña A Coruña15071 Spain

The rise of ubiquitous deepfakes, misinformation, disinformation and post-truth, often referred to as fake news, raises concerns over the role of Internet and social media in modern democratic societies. Due to its rapid and widespread diffusion, digital deception has not only an individual or societal cost, but it can lead to significant economic losses or to risks to national security. Blockchain and other Distributed Ledger Technologies (DLTs) guarantee the provenance and traceability of data by providing a transparent, immutable and verifiable record of transactions while creating a peer-to-peer secure platform for storing and exchanging information. This overview aims to explore the potential of DLTs to combat digital deception, describing the most relevant applications and identifying their main open challenges. Moreover, some recommendations are enumerated to guide future researchers on issues that will have to be tackled to strengthen the resilience against cyber-threats on today's online media. Copyright © 2019, The Authors. All rights reserved.

关键词： Cybersecurity

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X-Ray fluorescence image super-resolution using dictionary learning

X-Ray fluorescence image super-resolution using dictionary l...

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IEEE IVMSP Workshop

作者： Qiqin Dai Emeline Pouyet Oliver Cossairt Marc Walton Francesca Casadio Aggelos Katsaggelos Dpt. of Electrical Engineering and Computer Science Northwestern University Center for Scientific Studies in the Arts (NU-ACCESS) Northwestern University

ISBN: (纸本)9781509019304

X-Ray fluorescence (XRF) scanning of works of art is becoming an increasingly popular non-destructive analytical method. The high quality XRF spectra is necessary to obtain significant information on both major and minor elements used for characterization and provenance analysis. However, there is a trade-off between the spatial resolution of an XRF scan and the Signal-to-Noise Ratio (SNR) of each pixel's spectrum, due to the limited scanning time. In this paper, we propose an XRF image super-resolution method to address this trade-off, thus obtaining a high spatial resolution XRF scan with high SNR. We use a sparse representation of each pixel using a dictionary trained from the spectrum samples of the image, while imposing a spatial smoothness constraint on the sparse coefficients. We then increase the spatial resolution of the sparse coefficient map using a conventional super-resolution method. Finally the high spatial resolution XRF image is reconstructed by the high spatial resolution sparse coefficient map and the trained spectrum dictionary.

关键词： Dictionaries Spatial resolution Image reconstruction Mathematical model Signal resolution Signal to noise ratio

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