scholarly journals Coupled Anharmonic Thermochemistry from Stratified Monte-Carlo Integration

2021 ◽  
Author(s):  
Gabriel Rath ◽  
Wassja Kopp ◽  
Kai Leonhard
Keyword(s):  
Monte Carlo ◽  
Gas Phase ◽  
Classical Method ◽  
Monte Carlo Sampling ◽  
Monte Carlo Integration ◽  
Anharmonic Corrections ◽  
Fully Coupled ◽  
Better Than ◽  
The Ideal

This study presents CIMCI, a new semi-classical method for handling fully coupled anharmonicity in gas-phase thermodynamics that promises to be black-boxable, to be<br>applicable for all kinds of anharmonicity, and to scale better at higher dimensionality than other methods for handling gas-phase molecular anharmonicity. The method<br>does so by using automatically and recursively stratified, simultaneous Monte Carlo integration of multiple functions. For the small systems analyzed by this study, the<br>method’s anharmonic corrections match reference data better than those of other blackbox anharmonic methods, e.g. VPT2. This holds even when sampling with CIMCI<br>is done with primitive force fields, e.g. UFF, while the competing methods are used with proper, comprehensive potentials, e.g. the M06-2X meta-hybrid DFT functional.<br>With further refinements in Monte Carlo sampling efficiency, in the quality of fast potentials practical for Monte Carlo sampling, and in automatic detection of which stereoisomers should be included during sampling, CIMCI has the potential to be the ideal anharmonic treatment for larger molecules where the large number of conformers<br>and the high dimensionality of coupled torsions present major difficulties for other, existing treatments for anharmonicity.<br>

scholarly journals Coupled Anharmonic Thermochemistry from Stratified Monte-Carlo Integration

2021 ◽  
Author(s):  
Gabriel Rath ◽  
Wassja Kopp ◽  
Kai Leonhard
Keyword(s):  
Monte Carlo ◽  
Gas Phase ◽  
Classical Method ◽  
Monte Carlo Sampling ◽  
Monte Carlo Integration ◽  
Anharmonic Corrections ◽  
Fully Coupled ◽  
Better Than ◽  
The Ideal

This study presents CIMCI, a new semi-classical method for handling fully coupled anharmonicity in gas-phase thermodynamics that promises to be black-boxable, to be<br>applicable for all kinds of anharmonicity, and to scale better at higher dimensionality than other methods for handling gas-phase molecular anharmonicity. The method<br>does so by using automatically and recursively stratified, simultaneous Monte Carlo integration of multiple functions. For the small systems analyzed by this study, the<br>method’s anharmonic corrections match reference data better than those of other blackbox anharmonic methods, e.g. VPT2. This holds even when sampling with CIMCI<br>is done with primitive force fields, e.g. UFF, while the competing methods are used with proper, comprehensive potentials, e.g. the M06-2X meta-hybrid DFT functional.<br>With further refinements in Monte Carlo sampling efficiency, in the quality of fast potentials practical for Monte Carlo sampling, and in automatic detection of which stereoisomers should be included during sampling, CIMCI has the potential to be the ideal anharmonic treatment for larger molecules where the large number of conformers<br>and the high dimensionality of coupled torsions present major difficulties for other, existing treatments for anharmonicity.<br>

Asteroid masses obtained with INPOP planetary ephemerides

2019 ◽  
Vol 492 (1) ◽  
pp. 589-602 ◽  
Author(s):  
A Fienga ◽  
C Avdellidou ◽  
J Hanuš
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Sampling ◽  
New Method ◽  
Navigation Data ◽  
The Earth ◽  
Better Than ◽  
Juno Mission

ABSTRACT In this paper, we present masses of 103 asteroids deduced from their perturbations on the orbits of the inner planets, in particular Mars and the Earth. These determinations and the INPOP19a planetary ephemerides are improved by the recent Mars orbiter navigation data and the updated orbit of Jupiter based on the Juno mission data. More realistic mass estimates are computed by a new method based on random Monte Carlo sampling that uses up-to-date knowledge of asteroid bulk densities. We provide masses with uncertainties better than 33${{\ \rm per\ cent}}$ for 103 asteroids. Deduced bulk densities are consistent with those observed within the main spectroscopic complexes.

scholarly journals Rejection Sampling Schemes for Simulating from Arbitrary Probability Densities

2020 ◽  
Vol 68 (1) ◽  
pp. 59-64
Author(s):  
Anamul Haque Sajib
Keyword(s):  
Monte Carlo ◽  
Computational Cost ◽  
The Other ◽  
Rejection Sampling ◽  
Mcmc Method ◽  
Empirical Comparison ◽  
Sampling Schemes ◽  
Probability Densities ◽  
Better Than

Simulating random variates from arbitrary non-normalized probability densities, very often they do not have familiar forms, is an increasingly important requirement in many different fields, especially in Bayesian statistics. Accept-reject algorithm is one of the commonly used methods to simulate random variates from such densities but restriction on choosing proposal density under this framework (heavier tails than the target density) limits its applicability to a larger extent. On the other hand, Markov Chain Monte Carlo (MCMC) method can choose proposal density arbitrary which makes this method applicable to a larger class of target densities5. In addition to MCMC method, a more general widely used method known as ratio-of-uniforms (RoU) which requires only two uniform variates to simulate one variates from such densities. However, no empirical comparison among these methods for simulating random variates from such densities was seen in the literature. In this paper, we limit our study only to MCMC and RoU methods to simulate random variates from such densities. Following the generation of random variates from such densities using these two methods, we compare the performance of these two methods based on quality of the generated samples. Finally, we conclude that RoU method performs better than MCMC method as far as quality of the generated sample (randomness) and computational cost are concerned. Dhaka Univ. J. Sci. 68(1): 59-64, 2020 (January)

Asteroid masses obtained with INPOP planetary ephemerides

2020 ◽  
Author(s):  
Agnes Fienga ◽  
Chrysa Avdellidou ◽  
Josef Hanus
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Sampling ◽  
New Method ◽  
Navigation Data ◽  
The Earth ◽  
Better Than ◽  
Juno Mission

&lt;p&gt;We present here masses of 103 asteroids deduced from their perturbations on the&lt;br /&gt;orbits of the inner planets, in particular Mars and the Earth. These determinations and the&lt;br /&gt;INPOP19a planetary ephemerides are improved by the recent Mars orbiter navigation data&lt;br /&gt;and the updated orbit of Jupiter based on the Juno mission data. More realistic mass estimates&lt;br /&gt;are computed by a new method based on random Monte-Carlo sampling that uses up-to-date&lt;br /&gt;knowledge of asteroid bulk densities. We provide masses with uncertainties better than 33%&lt;br /&gt;for 103 asteroids. Deduced bulk densities are consistent with those observed within the main&lt;br /&gt;spectroscopic complexes.&lt;/p&gt;

Application of Monte Carlo Integration to Three-Dimensional Fluorescence Spectrometry

1995 ◽  
Vol 49 (9) ◽  
pp. 1239-1242 ◽  
Author(s):  
Yuan Yan ◽  
Jin-Gou Xu ◽  
Zhu-Guang Lin ◽  
Yi-Bin Zhao ◽  
Guo-Zhen Chen
Keyword(s):  
Monte Carlo ◽  
Fluorescence Intensity ◽  
Single Point ◽  
Three Dimensional ◽  
Monte Carlo Integration ◽  
Fluorescence Spectrometry ◽  
Total Fluorescence ◽  
Better Than

In this paper, the sensitivity of three-dimensional fluorescence spectrometry (TDFS) is studied by using the total fluorescence intensity, calculated by Monte Carlo integration, instead of conventional single-point intensity. It has been proven that the sensitivity of the total fluorescence intensity method is nearly one hundred times better than that of the single-point intensity method for the determinations of fluorescein and tryptophan. The mechanism of the method has also been studied.

scholarly journals QUASI MONTE CARLO INTEGRATION IN GRID ENVIRONMENTS: FURTHER LEAPING EFFECTS

2006 ◽  
Vol 16 (03) ◽  
pp. 285-311 ◽  
Author(s):  
HEINZ HOFBAUER ◽  
ANDREAS UHL ◽  
PETER ZINTERHOF
Keyword(s):  
Monte Carlo ◽  
Numerical Integration ◽  
Distributed System ◽  
Monte Carlo Integration ◽  
Quasi Monte Carlo ◽  
Grid Environments ◽  
Made In

The splitting of Quasi-Monte Carlo (QMC) point sequences into interleaved substreams has been suggested to raise the speed of distributed numerical integration and to lower the traffic on the network. The usefulness of this approach in GRID environments is discussed. After specifying requirements for using QMC techniques in GRID environments in general we review and evaluate the proposals made in literature so far. In numerical integration experiments we investigate the quality of single leaped QMC point sequence substreams, comparing the respective properties of Sobol', Halton, Faure, Niederreiter-Xing, and Zinterhof sequences in detail. Numerical integration results obtained on a distributed system show that leaping sensitivity varies tremendously among the different sequences and we provide examples of deteriorated results caused by leaping effects, especially in heterogeneous settings which would be expected in GRID environments.

scholarly journals An Algebraic Pedotransfer Function to Calculate Standardized in situ Determined Field Capacity

2016 ◽  
Vol 8 (8) ◽  
pp. 158 ◽  
Author(s):  
Theophilo B. Ottoni Filho ◽  
Isaias F. Leal ◽  
José Ronaldo De Macedo ◽  
Bruno C. B. Reis
Keyword(s):  
Classical Method ◽  
Organic Matter Content ◽  
Field Capacity ◽  
Matter Content ◽  
Pedotransfer Function ◽  
Different Depths ◽  
The Individual ◽  
Better Than

<p>Despite the large applicability of the field capacity (FC) concept in hydrology and engineering, it presents various ambiguities and inconsistencies due to a lack of methodological procedure standardization. Experimental field and laboratory protocols taken from the literature were used in this study to determine the value of FC for different depths in 29 soil profiles, totaling 209 soil samples. The volumetric water content (theta) values were also determined at three suction values (6 kPa, 10 kPa, 33 kPa), along with bulk density (BD), texture (T) and organic matter content (OM). The protocols were devised based on the water processes involved in the FC concept aiming at minimizing hydraulic inconsistencies and procedural difficulty while maintaining the practical meaning of the concept. A high correlation between FC and theta(6 kPa) allowed the development of a pedotransfer function (Equation 3) quadratic for theta(6 kPa), resulting in an accurate and nearly bias-free calculation of FC for the four database geographic areas, with a global root mean squared residue (RMSR) of 0.026 m<sup>3</sup>·m<sup>-3</sup>. At the individual soil profile scale, the maximum RMSR was only 0.040 m<sup>3</sup>·m<sup>-3</sup>. The BD, T and OM data were generally of a low predicting quality regarding FC when not accompanied by the moisture variables. As all the FC values were obtained by the same experimental protocol and as the predicting quality of Equation 3 was clearly better than that of the classical method, which considers FC equal to theta(6), theta(10) or theta(33), we recommend using Equation 3 rather than the classical method, as well as the protocol presented here, to determine in-situ FC.</p>

Effects of self-seeding and crystal post-selection on the quality of Monte Carlo-integrated SFX data

2015 ◽  
Vol 22 (3) ◽  
pp. 644-652 ◽  
Author(s):  
Thomas Barends ◽  
Thomas A. White ◽  
Anton Barty ◽  
Lutz Foucar ◽  
Marc Messerschmidt ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Data Collection ◽  
Data Quality ◽  
Monte Carlo Integration ◽  
Cell Parameters ◽  
Mode Of Operation ◽  
Linac Coherent Light Source ◽  
Sources Of Variation ◽  
Serial Femtosecond Crystallography

Serial femtosecond crystallography (SFX) is an emerging method for data collection at free-electron lasers (FELs) in which single diffraction snapshots are taken from a large number of crystals. The partial intensities collected in this way are then combined in a scheme called Monte Carlo integration, which provides the full diffraction intensities. However, apart from having to perform this merging, the Monte Carlo integration must also average out all variations in crystal quality, crystal size, X-ray beam properties and other factors, necessitating data collection from thousands of crystals. Because the pulses provided by FELs running in the typical self-amplified spontaneous emission (SASE) mode of operation have very irregular, spiky spectra that vary strongly from pulse to pulse, it has been suggested that this is an important source of variation contributing to inaccuracies in the intensities, and that, by using monochromatic pulses produced through a process called self-seeding, fewer images might be needed for Monte Carlo integration to converge, resulting in more accurate data. This paper reports the results of two experiments performed at the Linac Coherent Light Source in which data collected in both SASE and self-seeded mode were compared. Importantly, no improvement attributable to the use of self-seeding was detected. In addition, other possible sources of variation that affect SFX data quality were investigated, such as crystal-to-crystal variations reflected in the unit-cell parameters; however, these factors were found to have no influence on data quality either. Possibly, there is another source of variation as yet undetected that affects SFX data quality much more than any of the factors investigated here.

Kepuasan Masyarakat Terhadap Pelayanan Kelurahan Setelah Pemekaran Di Tangerang Selatan

Liquidity ◽  
2018 ◽  
Vol 2 (2) ◽  
pp. 151-159
Author(s):  
Pitri Yandri
Keyword(s):  
Public Perception ◽  
Service Personnel ◽  
Urban Services ◽  
Hospitality Workers ◽  
Care Workers ◽  
Before And After ◽  
Cartesian Diagram ◽  
Better Than

The purpose of this study is (1) to analyze public perception on urban services before and after the expansion of the region, (2) analyze the level of people's satisfaction with urban services, and (3) analyze the determinants of the variables that determine what level of people's satisfaction urban services. This study concluded that first, after the expansion, the quality of urban services in South Tangerang City is better than before. Secondly, however, public satisfaction with the services only reached 48.53% (poor scale). Third, by using a Cartesian Diagram, the second priority that must be addressed are: (1) clarity of service personnel, (2) the discipline of service personnel, (3) responsibility for care workers; (4) the speed of service, (5) the ability of officers services, (6) obtain justice services, and (7) the courtesy and hospitality workers.

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