Application of quadratically-constrained model predictive control in power systems

Simulations for the quadratically-constrained model predictive control (qc-MPC) with power system linear models are studied in this work. In qc-MPC, the optimization is imposed with two additional constraints to achieve the closed-loop system stability and the recursive-feasibility simultaneously. Instead of engaging the traditional terminal constraint for MPC, both constraints in qc-MPC are imposed on the first control vector of the MPC control sequence. As a result, qc-MPC has the potential for further extension to the control of network centric power systems. The algorithm of qc-MPC has been developed in a previous paper. Here, simulation studies with small-signal linear models of three typical power systems are presented to demonstrate its efficacy. We also develop a computational strategy for the decentralized static state-feedback control using the same quadratic dissipativity constraint as of the qc-MPC. Only state constraints are considered in the state feedback design. A comparison is then provided in the simulation study of qc-MPC relatively to the constrained-state feedback control.This publication is made possible by the Singapore National Research Foundation under its Campus for Research Excellence And Technological Enterprise (CREATE) programmeThis is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/ICARCV.2014.706430

Multiplexed model predictive control of interconnected systems

A Multiplexed Model Predictive Control (MMPC) scheme with Quadratic Dissipativity Constraint (QDC) for interconnected systems is presented in this paper. A centralized MMPC is designed for the global system, wherein the controls of subsystems are updated sequentially to reduce the computational time. In MMPC, the global state vector of the interconnected system is required by the optimization. The QDC is converted into an enforced stability constraint for the MMPC as an alternative to the terminal constraint and terminal cost in this approach. The nominal recursive feasibility for the global system and the iterative feasibility for the local subsystems are obtained via set operations on the invariant sets. The admissible sets for the control inputs are obtained and employed in this approach for the QDC-based stability constraint. The set operations are speed up by multiple magnitudes thanks to the implementation of multiplexed inputs in MMPC. Numerical simulations with Automatic Generation Control (AGC) in power systems having tie-lines demonstrate the theoretical development.The authors acknowledge the support by the Singapore National Research Foundation (NRF) under its Campus for Research Excellence And Technological Enterprise (CREATE) programme and the Cambridge Centre for Advanced Research in Energy Efficiency in Singapore (Cambridge CARES), C4T project.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/CDC.2015.740256

The Outstanding Decisions of the United States Supreme Court in 1954

We perform a kinematic and morphological analysis of 44 star-forming galaxies at z ̃ 2 in the COSMOS legacy field using near-infrared spectroscopy from Keck/MOSFIRE and F160W imaging from CANDELS/3D-HST as part of the ZFIRE survey. Our sample consists of cluster and field galaxies from 2.0 < z < 2.5 with K-band multi-object slit spectroscopic measurements of their Hα emission lines. Hα rotational velocities and gas velocity dispersions are measured using the Heidelberg Emission Line Algorithm (HELA), which compares directly to simulated 3D data cubes. Using a suite of simulated emission lines, we determine that HELA reliably recovers input S 0.5 and angular momentum at small offsets, but V 2.2/σ g values are offset and highly scattered. We examine the role of regular and irregular morphology in the stellar mass kinematic scaling relations, deriving the kinematic measurement S 0.5, and finding {log}({S}0.5)=(0.38+/- 0.07){log}(M/{M}☉ -10)+(2.04+/- 0.03) with no significant offset between morphological populations and similar levels of scatter (̃0.16 dex). Additionally, we identify a correlation between M ⋆ and V 2.2/σ g for the total sample, showing an increasing level of rotation dominance with increasing M ⋆, and a high level of scatter for both regular and irregular galaxies. We estimate the specific angular momenta (j disk) of these galaxies and find a slope of 0.36 ± 0.12, shallower than predicted without mass-dependent disk growth, but this result is possibly due to measurement uncertainty at M ⋆ < 9.5 However, through a Kolmogorov-Smirnov test we find irregular galaxies to have marginally higher j disk values than regular galaxies, and high scatter at low masses in both populations

Near infrared spectroscopy and star-formation histories of 3<z<4 quiescent galaxies

We present Keck-MOSFIRE H and K spectra for a sample of 24 candidate quiescent galaxies (QGs) at 3<z<4, identified from UVJ colors and photometric redshifts in the ZFOURGE and 3DHST surveys. We obtain spectroscopic redshifts for half of the sample, using absorption or emission lines, and confirm the high accuracy of the photometric redshifts with a median error of 1.2%. Two galaxies turn out to be dusty objects at lower redshifts (z<2.5), and are the only two detected in the sub-mm with ALMA. High equivalent-width [OIII] was observed in two galaxies, contributing up to 30% of the K-band flux and mimicking the colors of an old stellar population. This implies a failure rate of only 20% for the UVJ selection at these redshifts. Balmer absorption was identified in 4 of the brighest galaxies, confirming the absence of OB stars. Modeling all QGs with a wide range of star-formation histories, we find sSFR a factor of 10 below the main sequence (MS) for all but one galaxy, and less than 0.01 Gyr$^{-1}$ for half of the sample. This is consistent with the H$\beta$ and [OII] luminosities, and the ALMA non-detections. We then find that these QGs have quenched on average 300 Myr before observation, between z=3.5 and 5, and that they formed at z~5.5 with a mean SFR~300 Msun/yr. Considering an alternative selection of QGs based solely on the sSFR from SED modeling, we find that galaxies a factor 10 below the MS are 40% more numerous than UVJ-quiescent galaxies, implying that the UVJ selection is pure but incomplete. Current models fail at reproducing our observations and underestimate either the number density of QGs by more than an order of magnitude or the duration of their quiescence by a factor two. Overall, these results confirm the existence of an unexpected population of QGs at z>3, and offer the first insights on their formation history. [abridged]Comment: 30 pages (+ appendix), 18 figures, accepted for publication in A&

Galaxy Merger Fractions in Two Clusters at Z ∼ 2 Using the Hubble Space Telescope

We measure the fraction of galaxy-galaxy mergers in two clusters at z ,F∼ ,F2 using imaging and grism observations from the Hubble Space Telescope. The two galaxy cluster candidates were originally identified as overdensities of objects using deep mid-infrared imaging and observations from the Spitzer Space Telescope, and were subsequently followed up with HST/WFC3 imaging and grism observations. We identify galaxy-galaxy merger candidates using high-resolution imaging with the WFC3 in the F105W, F125W, and F160W bands. Coarse redshifts for the same objects are obtained with grism observations in G102 for the z ,F∼ ,F1.6 cluster (IRC0222A) and G141 for the z ,F∼ ,F2 cluster (IRC0222B). Using visual classifications as well as a variety of selection techniques, we measure merger fractions of in IRC0222A and in IRC0222B. In comparison, we measure a merger fraction of for field galaxies at z ,F∼ ,F2. Our study indicates that the galaxy-galaxy merger fraction in clusters at z ,F∼ ,F2 is enhanced compared to the field population, but note that more cluster measurements at this epoch are needed to confirm our findings

Causes and consequences of tipping points in river delta social-ecological systems

The sustainability of social-ecological systems within river deltas globally is in question as rapid development and environmental change trigger "negative” or “positive” tipping points depending on actors’ perspectives, e.g., regime shift from abundant sediment deposition to sediment shortage, agricultural sustainability to agricultural collapse or shift from rural to urban land. Using a systematic review of the literature, we show how cascading effects across anthropogenic, ecological, and geophysical processes have triggered numerous tipping points in the governance, hydrological and land use management of the world’s river deltas. Crossing tipping points had both positive and negative effects that generally enhanced economic development to the detriment of the environment. Assessment of deltas that featured prominently in the review revealed how outcomes of tipping points can inform the long-term trajectory of deltas towards sustainability or collapse. Management of key drivers at the delta scale can trigger positive tipping points to place social-ecological systems on a pathway towards sustainable development

Location of chlorogenic acid biosynthesis pathway and polyphenol oxidase genes in a new interspecific anchored linkage map of eggplant

© Gramazio et al.; licensee BioMed Central. 2014. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

Epitaxial growth of perovskite oxide films facilitated by oxygen vacancies

The authors would like to thank P. Yudin for valuable discussions, N. Nepomniashchaia for VASE studies, and S. Cichon for XPS analysis. The authors acknowledge support from the Czech Science Foundation (Grant No. 19-09671S), the European Structural and Investment Funds and the Ministry of Education, Youth and Sports of the Czech Republic through Programme ‘‘Research, Development and Education’’ (Project No. SOLID21 CZ.02.1.01/0.0/0.0/16-019/0000760), and ERA NET project Sun2Chem (E. K. and L. R.). Calculations have been done on the LASC Cluster in the ISSP UL.Single-crystal epitaxial films of technologically important and scientifically intriguing multifunctional ABO3 perovskite-type metal oxides are essential for advanced applications and understanding of these materials. In such films, a film-substrate misfit strain enables unprecedented crystal phases and unique properties that are not available in their bulk counterparts. However, the prerequisite growth of strained epitaxial films is fundamentally restricted by misfit relaxation. Here we demonstrate that introduction of a small oxygen deficiency concurrently stabilizes epitaxy and increases lattice strain in thin films of archetypal perovskite oxide SrTiO3. By combining experimental and theoretical methods, we found that lattice distortions around oxygen vacancies lead to anisotropic local stresses, which interact with the misfit strain in epitaxial films. Consequently, specific crystallographic alignments of the stresses are energetically favorable and can facilitate epitaxial growth of strained films. Because anisotropic oxygen-vacancy stresses are inherent to perovskite-type and many other oxides, we anticipate that the disclosed phenomenon of epitaxial stabilization by oxygen vacancies is relevant for a very broad range of functional oxides.This work is licensed under CC BY, CC BY-NC licenses.Czech Science Foundation (Grant No. 19-09671S); European Structural and Investment Funds and the Ministry of Education, Youth and Sports of the Czech Republic through Programme ‘‘Research, Development and Education’’ (Project No. SOLID21 CZ.02.1.01/0.0/0.0/16-019/0000760), and ERA NET project Sun2Chem; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO