scholarly journals An Improved Weak Pressure Gradient Scheme for Single-Column Modeling

2014 ◽  
Vol 71 (7) ◽  
pp. 2415-2429 ◽  
Author(s):  
Jacob P. Edman ◽  
David M. Romps
Keyword(s):  
Pressure Gradient ◽  
Gravity Waves ◽  
Large Scale ◽  
Atmospheric Models ◽  
Wave Resonance ◽  
Single Column ◽  
The One ◽  
New Formulation ◽  
Weak Pressure Gradient ◽  
Steady State Solutions

Abstract A new formulation of the weak pressure gradient approximation (WPG) is introduced for parameterizing large-scale dynamics in limited-domain atmospheric models. This new WPG is developed in the context of the one-dimensional, linearized, damped, shallow-water equations and then extended to Boussinesq and compressible fluids. Unlike previous supradomain-scale parameterizations, this formulation of WPG correctly reproduces both steady-state solutions and first baroclinic gravity waves. In so doing, this scheme eliminates the undesirable gravity wave resonance in previous versions of WPG. In addition, this scheme can be extended to accurately model the emission of gravity waves with arbitrary vertical wavenumber.

Fast and Robust Dictionary-based Classification for Image Data

2021 ◽  
Vol 15 (6) ◽  
pp. 1-22
Author(s):  
Shaoning Zeng ◽  
Bob Zhang ◽  
Jianping Gou ◽  
Yong Xu ◽  
Wei Huang
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Image Data ◽  
Robust Classification ◽  
Theoretical System ◽  
Learned Dictionary ◽  
And Performance ◽  
The One ◽  
New Formulation ◽  
Two Stages

Dictionary-based classification has been promising in knowledge discovery from image data, due to its good performance and interpretable theoretical system. Dictionary learning effectively supports both small- and large-scale datasets, while its robustness and performance depends on the atoms of the dictionary most of the time. Empirically, using a large number of atoms is helpful to obtain a robust classification, while robustness cannot be ensured when setting a small number of atoms. However, learning a huge dictionary dramatically slows down the speed of classification, which is especially worse on the large-scale datasets. To address the problem, we propose a Fast and Robust Dictionary-based Classification (FRDC) framework, which fully utilizes the learned dictionary for classification by staging - and -norms to obtain a robust sparse representation. The new objective function, on the one hand, introduces an additional -norm term upon the conventional -norm optimization, which generates a more robust classification. On the other hand, the optimization based on both - and -norms is solved in two stages, which is much easier and faster than current solutions. In this way, even when using a limited size of dictionary, which makes sure the classification runs very fast, it still can gain higher robustness for multiple types of image data. The optimization is then theoretically analyzed in a new formulation, close but distinct to elastic-net, to prove it is crucial to improve the performance under the premise of robustness. According to our extensive experiments conducted on four image datasets for face and object classification, FRDC keeps generating a robust classification no matter whether using a small or large number of atoms. This guarantees a fast and robust dictionary-based image classification. Furthermore, when simply using deep features extracted via some popular pre-trained neural networks, it outperforms many state-of-the-art methods on the specific datasets.

scholarly journals Large-Scale Modes in a Rotating Atmosphere with Radiative–Convective Instability and WISHE

2005 ◽  
Vol 62 (11) ◽  
pp. 4084-4094 ◽  
Author(s):  
Zeljka Fuchs ◽  
David J. Raymond
Keyword(s):  
Gravity Waves ◽  
Large Scale ◽  
Normal Modes ◽  
Moist Convection ◽  
Mean Flow ◽  
Beta Plane ◽  
Additional Mode ◽  
Diabatic Processes ◽  
Relaxation Time Scale ◽  
The One

Abstract A highly simplified parameterization of diabatic processes is applied to linearized equations on a equatorial beta plane. The diabatic processes include moist convection, cloud–radiation interactions (CRI), and wind-induced surface heat exchange (WISHE). The precipitation rate is assumed to increase linearly as the vertically averaged saturation deficit decreases. The modeled modes are Matsuno’s normal modes, that is, Kelvin waves, mixed Rossby–gravity waves, Rossby waves, and inertio–gravity waves, and an additional mode called here a slow moisture mode. All of the Matsuno modes are damped and remain stable even when CRI and WISHE are turned on. Their phase speeds do not vary much from Matsuno’s adiabatic values except for very long wavelength Kelvin and Rossby modes, for which the phase speeds are reduced compared to the adiabatic values. The slow moisture modes are stationary and unstable under CRI, while WISHE causes them to propagate. Under CRI and WISHE together the slow moisture modes are unstable and eastward propagating for long wavelengths and slowly moving relative to the mean flow for short wavelengths. The dispersion relations of the slow moisture modes are one of nearly constant or decreasing frequency with increasing wavenumber. The most important model parameter is the tropospheric moisture relaxation time scale, which is chosen to be 1 day. The model failed to explain the observed phase speeds of convectively coupled Matsuno modes. Following Mapes, the authors suggest that other dynamics, more realistic than the one including only the first baroclinic mode, may be responsible for these modes.

Additional Pressure Drop at a Bifurcation Due to the Passage of Flexible Disks in a Large Scale Model

1994 ◽  
Vol 116 (4) ◽  
pp. 497-501 ◽  
Author(s):  
Mohammad F. Kiani ◽  
Giles R. Cokelet
Keyword(s):  
Pressure Drop ◽  
Pressure Gradient ◽  
Large Scale ◽  
Reynolds Numbers ◽  
Side Branch ◽  
Scale Model ◽  
Upstream Region ◽  
Additional Pressure ◽  
Large Scale Model ◽  
The One

The flow of red blood cells (RBC) through a microvascular capillary bifurcation was modeled in a large scale system in which rigid circular tubes and bifurcations (diameter = .95 cm) simulated capillaries and capillary bifurcations, flexible disks (undeformed diameter = 0.75 cm) simulated RBC and glycerol simulated plasma. At low Reynolds numbers (0.01 to 0.1), pressure drop was measured in the tubes upstream and downstream from the bifurcation as well as across the bifurcation itself, for various flow splits at the bifurcation while the inflow in the upstream tube was held constant. Pressure gradient across the bifurcation is taken to be the average of the upstream and downstream pressure gradients if the additional pressure drop at the bifurcation due to the partitioning of flow and disks is negligible. For the case of glycerol alone, the ratio of pressure gradient (G) at the bifurcation to the one at the upstream region was always greater than expected and reached 1.14 when the flow in the side branch was zero. With introduction of flexible disks into the system, G at the bifurcation was as much as 10 times the G at the upstream region as disks came in contact with, or close to, the dividing line of the bifurcation and paused momentarily before they entered one or the other side of the bifurcation. The largest G was for even flow split at the bifurcation and the smallest G was for the case where the flow in the side branch was smallest. Therefore, for the range of tube hematocrits (0–30 percent) and flow splits tested here, a significant additional pressure drop at the bifurcation is observed.

Atmospheric Subseasonal Variability and Circulation Regimes: Spectra, Trends, and Uncertainties

2020 ◽  
Vol 33 (21) ◽  
pp. 9375-9390
Author(s):  
Nedjeljka Žagar ◽  
Žiga Zaplotnik ◽  
Khalil Karami
Keyword(s):  
Gravity Waves ◽  
Large Scale ◽  
Rossby Waves ◽  
Wave Activity ◽  
Subseasonal Variability ◽  
Zonal Wavenumber ◽  
Equatorial Wave ◽  
Wave Patterns ◽  
Meridional Mode ◽  
The One

AbstractThe globally integrated subseasonal variability associated with the two main atmospheric circulation regimes, the balanced (or Rossby) and unbalanced (or inertia–gravity) regimes, is evaluated for the four reanalysis datasets: ERA-Interim, JRA-55, MERRA, and ERA5. The results quantify amplitudes and trends in midlatitude traveling and quasi-stationary Rossby wave patterns as well as in the equatorial wave activity across scales. A statistically significant reduction of subseasonal variability is found in Rossby waves with zonal wavenumber k = 6 along with an increase in variability in wavenumbers k = 3–5 in the summer seasons of both hemispheres. The four reanalyses also agree regarding increased variability in the large-scale Kelvin waves, mixed Rossby–gravity waves, and westward-propagating inertio-gravity waves with the lowest meridional mode. The amplitude and sign of trends in inertia–gravity modes with smaller zonal scales and greater meridional modes differ between the ERA-Interim and JRA-55 datasets on the one hand and the ERA5 and MERRA data on the other. An increased variability in the ERA-Interim and JRA-55 accounts for positive trends in their total subseasonal variability.

First grammar books in the Habsburg Monarchy: individual initiative and regulatory interference by the state (1760s–1770s)

2020 ◽  
Vol 2019 (2 (11)) ◽  
pp. 137-157
Author(s):  
Olga V. Khavanova ◽  
Keyword(s):  
Eighteenth Century ◽  
State Policy ◽  
Large Scale ◽  
Language Use ◽  
Linguistic Diversity ◽  
Mother Tongue ◽  
German Language ◽  
Habsburg Monarchy ◽  
Private Initiative ◽  
The One

The second half of the eighteenth century in the lands under the sceptre of the House of Austria was a period of development of a language policy addressing the ethno-linguistic diversity of the monarchy’s subjects. On the one hand, the sphere of use of the German language was becoming wider, embracing more and more segments of administration, education, and culture. On the other hand, the authorities were perfectly aware of the fact that communication in the languages and vernaculars of the nationalities living in the Austrian Monarchy was one of the principal instruments of spreading decrees and announcements from the central and local authorities to the less-educated strata of the population. Consequently, a large-scale reform of primary education was launched, aimed at making the whole population literate, regardless of social status, nationality (mother tongue), or confession. In parallel with the centrally coordinated state policy of education and language-use, subjects-both language experts and amateur polyglots-joined the process of writing grammar books, which were intended to ease communication between the different nationalities of the Habsburg lands. This article considers some examples of such editions with primary attention given to the correlation between private initiative and governmental policies, mechanisms of verifying the textbooks to be published, their content, and their potential readers. This paper demonstrates that for grammar-book authors, it was very important to be integrated into the patronage networks at the court and in administrative bodies and stresses that the Vienna court controlled the process of selection and financing of grammar books to be published depending on their quality and ability to satisfy the aims and goals of state policy.

The Green New Deal

2019 ◽  
Author(s):  
Robert C. Hockett
Keyword(s):  
New Deal ◽  
Large Scale ◽  
Public Investment ◽  
Climate Science ◽  
Time Frame ◽  
White Paper ◽  
Good News ◽  
Carbon Neutrality ◽  
The One ◽  
In Virtue Of

This white paper lays out the guiding vision behind the Green New Deal Resolution proposed to the U.S. Congress by Representative Alexandria Ocasio-Cortez and Senator Bill Markey in February of 2019. It explains the senses in which the Green New Deal is 'green' on the one hand, and a new 'New Deal' on the other hand. It also 'makes the case' for a shamelessly ambitious, not a low-ball or slow-walked, Green New Deal agenda. At the core of the paper's argument lies the observation that only a true national mobilization on the scale of those associated with the original New Deal and the Second World War will be up to the task of comprehensively revitalizing the nation's economy, justly growing our middle class, and expeditiously achieving carbon-neutrality within the twelve-year time-frame that climate science tells us we have before reaching an environmental 'tipping point.' But this is actually good news, the paper argues. For, paradoxically, an ambitious Green New Deal also will be the most 'affordable' Green New Deal, in virtue of the enormous productivity, widespread prosperity, and attendant public revenue benefits that large-scale public investment will bring. In effect, the Green New Deal will amount to that very transformative stimulus which the nation has awaited since the crash of 2008 and its debt-deflationary sequel.

“Community Interests” and the Role of International Law in the Creation of a Global Market for Agricultural Land

2018 ◽  
Author(s):  
Jochen von Bernstorff
Keyword(s):  
International Law ◽  
Large Scale ◽  
Agricultural Land ◽  
Food Sovereignty ◽  
Global Market ◽  
Negative Consequences ◽  
Cultural Rights ◽  
Land Grab ◽  
Large Scale Land ◽  
The One

The chapter explores the notion of “community interests” with regard to the global “land-grab” phenomenon. Over the last decade, a dramatic increase of foreign investment in agricultural land could be observed. Bilateral investment treaties protect around 75 per cent of these large-scale land acquisitions, many of which came with associated social problems, such as displaced local populations and negative consequences for food security in Third World countries receiving these large-scale foreign investments. Hence, two potentially conflicting areas of international law are relevant in this context: Economic, social, and cultural rights and the principles of permanent sovereignty over natural resources and “food sovereignty” challenging large-scale investments on the one hand, and specific norms of international economic law stabilizing them on the other. The contribution discusses the usefulness of the concept of “community interests” in cases where the two colliding sets of norms are both considered to protect such interests.

scholarly journals Influence of the Upstream Terrain on the Formation of a Cold Frontal Snowband in Northeast China

2021 ◽  
Author(s):  
Na Li ◽  
Baofeng Jiao ◽  
Lingkun Ran ◽  
Zongting Gao ◽  
Shouting Gao
Keyword(s):  
Gravity Waves ◽  
Northeast China ◽  
Large Scale ◽  
Control Experiment ◽  
Vertical Motion ◽  
Near Surface ◽  
Inertial Instability ◽  
Two Factors ◽  
Negative Effect ◽  
Conditional Instability

AbstractWe investigated the influence of upstream terrain on the formation of a cold frontal snowband in Northeast China. We conducted numerical sensitivity experiments that gradually removed the upstream terrain and compared the results with a control experiment. Our results indicate a clear negative effect of upstream terrain on the formation of snowbands, especially over large-scale terrain. By thoroughly examining the ingredients necessary for snowfall (instability, lifting and moisture), we found that the release of mid-level conditional instability, followed by the release of low-level or near surface instabilities (inertial instability, conditional instability or conditional symmetrical instability), contributed to formation of the snowband in both experiments. The lifting required for the release of these instabilities was mainly a result of frontogenetic forcing and upper gravity waves. However, the snowband in the control experiment developed later and was weaker than that in the experiment without upstream terrain. Two factors contributed to this negative topographic effect: (1) the mountain gravity waves over the upstream terrain, which perturbed the frontogenetic circulation by rapidly changing the vertical motion and therefore did not favor the release of instabilities in the absence of persistent ascending motion; and (2) the decrease in the supply of moisture as a result of blocking of the upstream terrain, which changed both the moisture and instability structures leeward of the mountains. A conceptual model is presented that shows the effects of the instabilities and lifting on the development of cold frontal snowbands in downstream mountains.

scholarly journals State Management for Cloud-Native Applications

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 423
Author(s):  
Márk Szalay ◽  
Péter Mátray ◽  
László Toka
Keyword(s):  
Large Scale ◽  
Distributed Databases ◽  
Access Time ◽  
Replica Placement ◽  
State Management ◽  
Placement Decisions ◽  
Dynamic Replication ◽  
Cloud Databases ◽  
Placement Algorithm ◽  
The One

The stateless cloud-native design improves the elasticity and reliability of applications running in the cloud. The design decouples the life-cycle of application states from that of application instances; states are written to and read from cloud databases, and deployed close to the application code to ensure low latency bounds on state access. However, the scalability of applications brings the well-known limitations of distributed databases, in which the states are stored. In this paper, we propose a full-fledged state layer that supports the stateless cloud application design. In order to minimize the inter-host communication due to state externalization, we propose, on the one hand, a system design jointly with a data placement algorithm that places functions’ states across the hosts of a data center. On the other hand, we design a dynamic replication module that decides the proper number of copies for each state to ensure a sweet spot in short state-access time and low network traffic. We evaluate the proposed methods across realistic scenarios. We show that our solution yields state-access delays close to the optimal, and ensures fast replica placement decisions in large-scale settings.

scholarly journals Constructing Large-Scale Genetic Maps Using an Evolutionary Strategy Algorithm

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 2269-2282
Author(s):  
D Mester ◽  
Y Ronin ◽  
D Minkov ◽  
E Nevo ◽  
A Korol
Keyword(s):  
Discrete Optimization ◽  
High Performance ◽  
Large Scale ◽  
Simulated Data ◽  
Real Data ◽  
Genetic Maps ◽  
Chromosome 1 ◽  
Evolutionary Strategy ◽  
Group A ◽  
The One

Abstract This article is devoted to the problem of ordering in linkage groups with many dozens or even hundreds of markers. The ordering problem belongs to the field of discrete optimization on a set of all possible orders, amounting to n!/2 for n loci; hence it is considered an NP-hard problem. Several authors attempted to employ the methods developed in the well-known traveling salesman problem (TSP) for multilocus ordering, using the assumption that for a set of linked loci the true order will be the one that minimizes the total length of the linkage group. A novel, fast, and reliable algorithm developed for the TSP and based on evolution-strategy discrete optimization was applied in this study for multilocus ordering on the basis of pairwise recombination frequencies. The quality of derived maps under various complications (dominant vs. codominant markers, marker misclassification, negative and positive interference, and missing data) was analyzed using simulated data with ∼50-400 markers. High performance of the employed algorithm allows systematic treatment of the problem of verification of the obtained multilocus orders on the basis of computing-intensive bootstrap and/or jackknife approaches for detecting and removing questionable marker scores, thereby stabilizing the resulting maps. Parallel calculation technology can easily be adopted for further acceleration of the proposed algorithm. Real data analysis (on maize chromosome 1 with 230 markers) is provided to illustrate the proposed methodology.

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