1,661 research outputs found
VCC-LF dataset
No full textThis is readme for VCC-LF dataset.
This dataset provides light field mat files that capture by Lytro I.
The light field resolusion is [h,w,u,v,d].
If you use these data or our toolkit code, please cite our paper properly
@inproceedings{ lirsiggraphasia2019,
title={Hierarchical and View-invariant Light Field Segmentation by Maximizing Entropy Rate on 4D Ray Graphs},
author={Li, Rui and Heidrich, Wolfgang},
booktitle={ACM Transactions on Graphics (Proc. SIGGRAPH Asia)},
year={2019},
publisher={ACM}
LF-copying without LF
No full textAbstractA copying approach to ellipsis is presented, whereby the locus of copying is not a level of derived syntactic structure (LF), but rather the derivation itself. The ban on preposition stranding in sprouting follows without further stipulation, and other, seemingly structure sensitive, empirical generalizations about elliptical constructions, including the preposition stranding generalization, follow naturally as well. Destructive operations which ‘repair’ non-identical antecedents are recast in terms of exact identity of derivations with parameters. In the context of a compositional semantic interpretation scheme, the derivational copying approach to ellipsis presented here is revealed to be a particular instance of a proform theory, thus showing that the distinctions between, and arguments about, syntactic and semantic theories of ellipsis need to be revisited
Temperate southern Australian coastal waters are characterised by surprisingly high rates of nitrogen fixation and diversity of diazotrophs
No full textBiological dinitrogen (N2) fixation is one mechanism by which specific microorganisms (diazotrophs) can ameliorate nitrogen (N) limitation. Historically, rates of N2 fixation were believed to be limited outside of the low nutrient tropical and subtropical open ocean; however, emerging evidence suggests that N2 fixation is also a significant process within temperate coastal waters. Using a combination of amplicon sequencing, targeting the nitrogenase reductase gene (nifH ), quantitative nifH PCR, and 15N2 stable isotope tracer experiments, we investigated spatial patterns of diazotroph assemblage structure and N2 fixation rates within the temperate coastal waters of southern Australia during Austral autumn and summer. Relative to previous studies in open ocean environments, including tropical northern Australia, and tropical and temperate estuaries, our results indicate that high rates of N2 fixation (10—64 nmol L¯1 d¯1) can occur within the large inverse estuary Spencer Gulf, while comparatively low rates of N2 fixation (2 nmol L¯1 d¯1) were observed in the adjacent continental shelf waters. Across the dataset, low concentrations ofNO3/NO2 were significantly correlated with the highest N2 fixation rates, suggesting that N2 fixation could be an important source of new N in the region as dissolved inorganic N concentrations are typically limiting. Overall, the underlying diazotrophic community was dominated by nifH sequences from Cluster 1 unicellular cyanobacteria of the UCYN-A clade, as well as non-cyanobacterial diazotrophs related to Pseudomonas stutzeri, and Cluster 3 sulfate- reducing deltaproteobacteria. Diazotroph community composition was significantly influenced by salinity and SiO4 concentrations, reflecting the transition from UCYN-A- dominated assemblages in the continental shelf waters, to Cluster 3-dominated assem- blages in the hypersaline waters of the inverse estuary. Diverse, transitional diazotrophic communities, comprised of a mixture of UCYN-A and putative heterotrophic bacteria, were observed at the mouth and southern edge of Spencer Gulf, where the highest N2 fixation rates were observed. In contrast to observations in other environments, no seasonal patterns in N2 fixation rates and diazotroph community structure were apparent. Collectively, our findings are consistent with the emerging view that N2Lauren F. Messer, Mark V. Brown, Paul D. Van Ruth, Mark Doubell and
Justin R. Seymou
Polynomial Approximation in Ep(D) with 0 < p < 1
No full textAbstractIn this paper, we construct approximants by means of interpolation polynomialsto prove Jackson′s theorem and the Bernstein inequality in Ep(D) with 0 < p < 1
Mean Convergence of Interpolation Polynomials in a Domain with Corners
No full textAbstractIn this paper, we prove mean convergence of interpolation polynomials in a domain with some corners
Machine learning and digital twins: monitoring and control for dynamic security in power systems
No full textThe reader of the chapter will be able to connect techniques from machine learning (ML) and digital twins (DTs) to gain insights for monitoring and control of (dynamic) security for electrical power systems. DTs are validated and verified high-fidelity (hf) models providing high simulation accuracy. DTs can be used for simulation of the supervised process of system operation and are therefore able to provide synthetic studied data, where measurement data are scarce. However, for some real-time applications in monitoring and control, such high-fidelity simulation models are not appropriate due to the corresponding computational barrier. There, ML aims to create an application-specific, low-fidelity (lf) approximation of the digital twin. Such trained lf models are used in real-time applications where computational time is scarce and lf information is sufficient. The conceptual intersection of hf and lf models has been little explored and becomes increasingly complex. This chapter aims to provide a conceptual overview of how such hf and lf models can be combined. This chapter is split into two parts where the first part is to introduce ML, lf models, and digital twins, hf models, for power systems analysis, and the second chapter is to use these two types of models to form purpose-driven surrogate lf models, illustrated on the example of dynamic security assessment (DSA). In the first part, the concepts for using DTs as hf models for online power system studies and their corresponding tuning of model parameters are introduced. Subsequently, ML i.e., lf models, are introduced and their corresponding training frameworks. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Intelligent Electrical Power Grid
Deep spectroscopic luminosity function of Abell 85 : no evidence for a steep upturn of the faint-end slope
No full textIA, AD and ALS acknowledge partial support from the INFN grant InDark and from the grant Progetti di Ateneo TO Call 2012 0011 ‘Marco Polo’ of the University of Torino.We present a new deep determination of the spectroscopic luminosity function (LF) within the virial radius of the nearby and massive Abell 85 (A85) cluster down to the dwarf regime (M* + 6) using Very Large Telescope/Visible Multi-Object Spectrograph (VLT/VIMOS) spectra for ∼2000 galaxies with mr ≤ 21 mag and 〈μe,r〉 ≤ 24 mag arcsec−2. The resulting LF from 438 cluster members is best modelled by a double Schechter function due to the presence of a statistically significant upturn at the faint end. The amplitude of this upturn (αf ~ -1.58+0.19-0.15), however, is much smaller than that of the Sloan Digital Sky Survey (SDSS) composite photometric cluster LF by Popesso et al., αf ∼ −2. The faint-end slope of the LF in A85 is consistent, within the uncertainties, with that of the field. The red galaxy population dominates the LF at low luminosities, and is the main factor responsible for the upturn. The fact that the slopes of the spectroscopic LFs in the field and in a cluster as massive as A85 are similar suggests that the cluster environment does not play a major role in determining the abundance of low-mass galaxies.Peer reviewe
An Auto-Zero-Stabilized Voltage Buffer With a Quiet Chopping Scheme and Constant Sub-pA Input Current
No full textThis article describes an auto-zero stabilized voltage buffer that achieves low offset and low noise with sub-pA input current. A high gain stabilization loop is used to periodically cancel the buffer’s offset. The loop itself is periodically disconnected from the buffer and auto-zeroed, during which its bandwidth is reduced to reduce the associated noise folding. However, this also reduces its offset correction range, and so to avoid overloading, its initial offset is digitally trimmed. To break up the correlation between the residual low-frequency (LF) noise of the auto-zero and stabilization phases, the loop is periodically chopped, which significantly reduces the buffer’s LF noise. Finally, the duty-cycle of the two phases is optimized to bring the buffer’s LF noise density close to 2–√ times its white noise density (14 nV/ Hz−−−√ ), which is the fundamental limit of an AZ amplifier. The buffer also achieves a constant and low input current (0.8 pA), as well as a state-of-the-art offset (0.4 μV ).Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Diversity and activity of diazotrophs in great barrier reef surface waters
No full text© 2017 Messer, Brown, Furnas, Carney, McKinnon and Seymour. Discrepancies between bioavailable nitrogen (N) concentrations and phytoplankton growth rates in the oligotrophic waters of the Great Barrier Reef (GBR) suggest that undetermined N sources must play a significant role in supporting primary productivity. One such source could be biological dinitrogen (N2) fixation through the activity of "diazotrophic" bacterioplankton. Here, we investigated N2 fixation and diazotroph community composition over 10° S of latitude within GBR surface waters. Qualitative N2 fixation rates were found to be variable across the GBR but were relatively high in coastal, inner and outer GBR waters, reaching 68 nmol L-1 d-1. Diazotroph assemblages, identified by amplicon sequencing of the nifH gene, were dominated by the cyanobacterium Trichodesmium erythraeum, γ-proteobacteria from the Gamma A clade, and δ-proteobacterial phylotypes related to sulfate-reducing genera. However, diazotroph communities exhibited significant spatial heterogeneity, correlated with shifts in dissolved inorganic nutrient concentrations. Specifically, heterotrophic diazotrophs generally increased in relative abundance with increasing concentrations of phosphate and N, while Trichodesmium was proportionally more abundant when concentrations of these nutrients were low. This study provides the first in-depth characterization of diazotroph community composition and N2 fixation dynamics within the oligotrophic, N-limited surface waters of the GBR. Our observations highlight the need to re-evaluate N cycling dynamics within oligotrophic coral reef systems, to include diverse N2 fixing assemblages as a potentially significant source of dissolved N within the water column
Optimal flow for general multi-carrier energy systems,including load flow equations
No full textOptimization is an important tool for the operation of an energy system. Multi-carrier energy systems (MESs) have recently become more important. Load ow (LF) equations are used within optimization to determine if physical network limits are violated. The way these LF equations are included in the optimal ow (OF) problem, influences the solvability of the OF problem and the convergence of the optimization algorithms. This paper considers two ways to include the LF equations within the OF problem for general MESs. In the first formulation, optimization is over the combined control and system-state variables, with the LF equations included explicitly as equality constraints. In the second formulation, optimization is over the control variables only. The system-state variables are solved from the LF equations in a separate subsystem, given the control variables. Hence, the LF equations are included only implicitly in the second formulation. The two formulations are compared theoretically. The effect of the two formulations on the solvability of the OF problem is illustrated by optimizing two MESs. Both formulation I and formulation II result in a solvable OF problem. For the two example MESs, the optimization algorithms require significantly fewer iterations with formulation II than with formulation I. For formulation II, the direct and the adjoint approach can be used to determine the required derivatives within the optimization algorithms. Scaling is needed to solve the OF problem for MESs. Both matrix scaling and per unit scaling can be used, but they are not equivalent. Numerical Analysi
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