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Статті в журналах з теми "Multi-Well correlations":
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Huang, Sheng-Jun, and Zhi-Hua Zhou. "Multi-Label Learning by Exploiting Label Correlations Locally." Proceedings of the AAAI Conference on Artificial Intelligence 26, no. 1 (September 20, 2021): 949–55. http://dx.doi.org/10.1609/aaai.v26i1.8287.
Анотація:
It is well known that exploiting label correlations is important for multi-label learning. Existing approaches typically exploit label correlations globally, by assuming that the label correlations are shared by all the instances. In real-world tasks, however, different instances may share different label correlations, and few correlations are globally applicable. In this paper, we propose the ML-LOC approach which allows label correlations to be exploited locally. To encode the local influence of label correlations, we derive a LOC code to enhance the feature representation of each instance. The global discrimination fitting and local correlation sensitivity are incorporated into a unified framework, and an alternating solution is developed for the optimization. Experimental results on a number of image, text and gene data sets validate the effectiveness of our approach.
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Bikondoa, Oier. "On the use of two-time correlation functions for X-ray photon correlation spectroscopy data analysis." Journal of Applied Crystallography 50, no. 2 (February 17, 2017): 357–68. http://dx.doi.org/10.1107/s1600576717000577.
Анотація:
Multi-time correlation functions are especially well suited to study non-equilibrium processes. In particular, two-time correlation functions are widely used in X-ray photon correlation experiments on systems out of equilibrium. One-time correlations are often extracted from two-time correlation functions at different sample ages. However, this way of analysing two-time correlation functions is not unique. Here, two methods to analyse two-time correlation functions are scrutinized, and three illustrative examples are used to discuss the implications for the evaluation of the correlation times and functional shape of the correlations.
3
Li, Yi-An, Dong-Fang Wang, Song Zhang, and Yu-Gang Ma. "System scan of the multiplicity correlation between forward and backward rapidities in relativistic heavy-ion collisions using a multi-phase transport model *." Chinese Physics C 46, no. 4 (April 1, 2022): 044101. http://dx.doi.org/10.1088/1674-1137/ac3bc9.
Анотація:
Abstract A systematic study on forward–backward (FB) multiplicity correlations from large systems to small ones through a multi-phase transport model (AMPT) has been performed and the phenomenon that correlation strength increases with centrality can be explained by taking the distribution of events as the superposition of a series of Gaussian distributions. It is also found that correlations in the plane can imply the shape of the event. Furthermore, long-range correlations originate from the fluctuations associated with the source information. FB correlations allow us to decouple long-range correlations from short-range correlations, and may provide a chance to investigate the α-clustering structure in initial colliding light nuclei as well. It seems the tetrahedron 16O + 16O collision gives a more uniform and symmetrical fireball, that emits the final particles more isotropically or independently in the longitudinal direction, indicating that the forward–backward multiplicity correlation could be used to identify the pattern of α-clustered 16O in future experiments.
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MARABEL ROMO, JACINTO. "WORST-OF OPTIONS AND CORRELATION SKEW UNDER A STOCHASTIC CORRELATION FRAMEWORK." International Journal of Theoretical and Applied Finance 15, no. 07 (November 2012): 1250051. http://dx.doi.org/10.1142/s0219024912500513.
Анотація:
This article considers a multi-asset model based on Wishart processes that accounts for stochastic volatility and for stochastic correlations between the underlying assets, as well as between their volatilities. The model accounts for the existence of correlation term structure and correlation skew. The article shows that the Wishart specification can generate different patterns corresponding to the correlation skew for a wide range of correlation term structures. Another advantage of the model is that it is analytically tractable and, hence, it is possible to obtain semi-closed-form solutions for the prices of plain vanilla options, as well as for the price of exotic derivatives. In this sense, this article develops semi-closed-form formulas for the price of European worst-of options with barriers and/or forward-start features. To motivate the introduction of the Wishart volatility model, the article compares the prices obtained under this model and under a multi-asset stochastic volatility model with constant instantaneous correlations. The results reveal the existence of a stochastic correlation premium and show that the consideration of stochastic correlation is a key element for the valuation of these structures.
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Feng, Lei, Bo An, and Shuo He. "Collaboration Based Multi-Label Learning." Proceedings of the AAAI Conference on Artificial Intelligence 33 (July 17, 2019): 3550–57. http://dx.doi.org/10.1609/aaai.v33i01.33013550.
Анотація:
It is well-known that exploiting label correlations is crucially important to multi-label learning. Most of the existing approaches take label correlations as prior knowledge, which may not correctly characterize the real relationships among labels. Besides, label correlations are normally used to regularize the hypothesis space, while the final predictions are not explicitly correlated. In this paper, we suggest that for each individual label, the final prediction involves the collaboration between its own prediction and the predictions of other labels. Based on this assumption, we first propose a novel method to learn the label correlations via sparse reconstruction in the label space. Then, by seamlessly integrating the learned label correlations into model training, we propose a novel multi-label learning approach that aims to explicitly account for the correlated predictions of labels while training the desired model simultaneously. Extensive experimental results show that our approach outperforms the state-of-the-art counterparts.
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Cao, Yang, Detian Liu, Qizheng Yin, Fei Xue, and Hengliang Tang. "MSASGCN : Multi-Head Self-Attention Spatiotemporal Graph Convolutional Network for Traffic Flow Forecasting." Journal of Advanced Transportation 2022 (June 17, 2022): 1–15. http://dx.doi.org/10.1155/2022/2811961.
Анотація:
Traffic flow forecasting is an essential task of an intelligent transportation system (ITS), closely related to intelligent transportation management and resource scheduling. Dynamic spatial-temporal dependencies in traffic data make traffic flow forecasting to be a challenging task. Most existing research cannot model dynamic spatial and temporal correlations to achieve well-forecasting performance. The multi-head self-attention mechanism is a valuable method to capture dynamic spatial-temporal correlations, and combining it with graph convolutional networks is a promising solution. Therefore, we propose a multi-head self-attention spatiotemporal graph convolutional network (MSASGCN) model. It can effectively capture local correlations and potential global correlations of spatial structures, can handle dynamic evolution of the road network, and, in the time dimension, can effectively capture dynamic temporal correlations. Experiments on two real datasets verify the stability of our proposed model, obtaining a better prediction performance than the baseline algorithms. The correlation metrics get significantly reduced compared with traditional time series prediction methods and deep learning methods without using graph neural networks, according to MAE and RMSE results. Compared with advanced traffic flow forecasting methods, our model also has a performance improvement and a more stable prediction performance. We also discuss some problems and challenges in traffic forecasting.
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Lin, Bridget M., Hunyong Cho, Chuwen Liu, Jeff Roach, Apoena Aguiar Ribeiro, Kimon Divaris, and Di Wu. "BZINB Model-Based Pathway Analysis and Module Identification Facilitates Integration of Microbiome and Metabolome Data." Microorganisms 11, no. 3 (March 16, 2023): 766. http://dx.doi.org/10.3390/microorganisms11030766.
Анотація:
Integration of multi-omics data is a challenging but necessary step to advance our understanding of the biology underlying human health and disease processes. To date, investigations seeking to integrate multi-omics (e.g., microbiome and metabolome) employ simple correlation-based network analyses; however, these methods are not always well-suited for microbiome analyses because they do not accommodate the excess zeros typically present in these data. In this paper, we introduce a bivariate zero-inflated negative binomial (BZINB) model-based network and module analysis method that addresses this limitation and improves microbiome–metabolome correlation-based model fitting by accommodating excess zeros. We use real and simulated data based on a multi-omics study of childhood oral health (ZOE 2.0; investigating early childhood dental caries, ECC) and find that the accuracy of the BZINB model-based correlation method is superior compared to Spearman’s rank and Pearson correlations in terms of approximating the underlying relationships between microbial taxa and metabolites. The new method, BZINB-iMMPath, facilitates the construction of metabolite–species and species–species correlation networks using BZINB and identifies modules of (i.e., correlated) species by combining BZINB and similarity-based clustering. Perturbations in correlation networks and modules can be efficiently tested between groups (i.e., healthy and diseased study participants). Upon application of the new method in the ZOE 2.0 study microbiome–metabolome data, we identify that several biologically-relevant correlations of ECC-associated microbial taxa with carbohydrate metabolites differ between healthy and dental caries-affected participants. In sum, we find that the BZINB model is a useful alternative to Spearman or Pearson correlations for estimating the underlying correlation of zero-inflated bivariate count data and thus is suitable for integrative analyses of multi-omics data such as those encountered in microbiome and metabolome studies.
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Pumpe, Daniel, Martin Reinecke, and Torsten A. Enßlin. "Denoising, deconvolving, and decomposing multi-domain photon observations." Astronomy & Astrophysics 619 (November 2018): A119. http://dx.doi.org/10.1051/0004-6361/201832781.
Анотація:
Astronomical imaging based on photon count data is a non-trivial task. In this context we show how to denoise, deconvolve, and decompose multi-domain photon observations. The primary objective is to incorporate accurate and well motivated likelihood and prior models in order to give reliable estimates about morphologically different but superimposed photon flux components present in the data set. Thereby we denoise and deconvolve photon counts, while simultaneously decomposing them into diffuse, point-like and uninteresting background radiation fluxes. The decomposition is based on a probabilistic hierarchical Bayesian parameter model within the framework of information field theory (IFT). In contrast to its predecessor D3PO, D4PO reconstructs multi-domain components. Thereby each component is defined over its own direct product of multiple independent domains, for example location and energy. D4PO has the capability to reconstruct correlation structures over each of the sub-domains of a component separately. Thereby the inferred correlations implicitly define the morphologically different source components, except for the spatial correlations of the point-like flux. Point-like source fluxes are spatially uncorrelated by definition. The capabilities of the algorithm are demonstrated by means of a synthetic, but realistic, mock data set, providing spectral and spatial information about each detected photon. D4PO successfully denoised, deconvolved, and decomposed a photon count image into diffuse, point-like and background flux, each being functions of location as well as energy. Moreover, uncertainty estimates of the reconstructed fields as well as of their correlation structure are provided employing their posterior density function and accounting for the manifolds the domains reside on.
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Hoffreumon, Timothée, and Ognyan Oreshkov. "The Multi-round Process Matrix." Quantum 5 (January 20, 2021): 384. http://dx.doi.org/10.22331/q-2021-01-20-384.
Анотація:
We develop an extension of the process matrix (PM) framework for correlations between quantum operations with no causal order that allows multiple rounds of information exchange for each party compatibly with the assumption of well-defined causal order of events locally. We characterise the higher-order process describing such correlations, which we name the multi-round process matrix (MPM), and formulate a notion of causal nonseparability for it that extends the one for standard PMs. We show that in the multi-round case there are novel manifestations of causal nonseparability that are not captured by a naive application of the standard PM formalism: we exhibit an instance of an operator that is both a valid PM and a valid MPM, but is causally separable in the first case and can violate causal inequalities in the second case due to the possibility of using a side channel.
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Dobrowolski, Janusz A. "Noise Characterization of Differential Multi- Element Multiport Networks - the Wave Approach." International Journal of Electronics and Telecommunications 61, no. 4 (December 1, 2015): 395–401. http://dx.doi.org/10.2478/eletel-2015-0052.
Анотація:
Abstract In this paper there is presented and discussed a general analysis method for noise characterization of noisy multielement multiport differential networks. It is based on mixed mode, differential and common mode, noise waves representation of noise, generalized mixed-mode scattering parameters and generalized mixed-mode noise wave correlation parameters for the network. There are derived analytical relation between the noise figure for a given output port and the noise matrix and the scattering parameters of the network, as well as the correlations between the input port noise waves. The signal to noise ratio degradation factor is derived and discussed, too. Presented results can be implemented directly in a CAD software for noise analysis of differential microwave multi-element multiport networks with differential as well as with conventional single ended ports.
Дисертації з теми "Multi-Well correlations":
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Baville, Paul. "Stratigraphic correlation uncertainty : On the impact of the sediment transport direction in computer-assisted multi-well correlation." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0111.
Анотація:
La modélisation du sous-sol est un moyen de prédire la structure et la connectivité des unités stratigraphiques en honorant les observations de subsurface. Ces observations sont en général échantillonées le long de puits à grande échelle horizontale (kilomètre) mais à petite échelle verticale (mètre). Il y a deux types de données de puits : (1) les diagraphies, qui correspondent à des acquisitions géophysiques quasi-continus (échatillonage régulier) le long du puits (e.g., gamma ray, sonic, porosité neutron), et (2) les régions, qui correspondent à des propriétés réservoir discrètes définies par des profondeurs maximales et minimales le long du puits (e.g., biozones, zones structurales, faciès sédimentaires). Des marqueurs sont interprétés le long des puits et peuvent être associés pour générer un ensemble d'associations de marqueurs conformes, appelé des corrélations de puits. Ces corrélations de puits peuvent être réalisées manuellement (approche déterministe) par des experts, mais cela peut être sujet à des biais et ne garantit pas la reproductibilité. Les corrélations de puits peuvent également être générées automatiquement (approche déterministe ou probabiliste) en calculant à l'aide d'un algorithme un grand nombre de corrélations de puits conformes et en classant ces réalisations en fonction de leurs vraisemblances. La vraisemblance de ces corrélations de puits assistées par ordinateur est directement liée au principe de corrélation utilisé pour associer les marqueurs. Ces travaux de thèse introduisent deux principes de corrélation, qui tendent à reproduire la chronostratigraphie et les processus de dépôts à l'échelle de la paraséquence : (1) "un marqueur (décrit par un faciès et une distalité pris au centre d'un intervalle ayant un faciès constant et une distalité constante) ne peut pas être associé avec un autre marqueur décrit par un faciès plus profond à une position plus proximale, ou un faciès moins profond à une position plus distale", et (2) "plus la différence entre une interpolation chronostratigraphique (entre les marqueurs) et un profil de dépôt conceptuel est faible, plus la probabilité d'association des marqueurs est élevée". Ces deux principes de corrélation sont d'abord validés avec des solutions analytiques et appliqués sur des cas synthétiques. Ils ont ensuite été utilisés (1) pour prédire la connectivité des unités stratigraphiques à partir de données de puits sans connaissances solides sur les environnements de dépôt en inférant les paramètres de corrélation, ou (2) pour évaluer la probabilité d'un environnement de dépôt hypothétique en générant des réalisations stochastiques et en évaluant les incertitudes. Les methodes sont appliquées sur un système silicoclastique de dépôts deltaïques côtiers ciblant un réservoir du Jurassique Moyen dans le South Viking Graben en Mer du Nord. Ces travaux de thèse permettent (1) de définir deux principes de corrélation spécifiques définis par quelques paramètres qui peuvent être utilisés pour générer des corrélations de puits stochastiques dans les systèmes deltaïques côtiers, et (2) d'ouvrir la voie vers une combinaison simple de principes de corrélation spécifiques pour obtenir une meilleure caractérisation des systèmes deltaïques côtiers en évaluant les incertitudesSubsurface modeling is a way to predict the structure and the connectivity of stratigraphic units by honoring subsurface observations. These observations are commonly be sampled along wells at a large and sparse horizontal scale (kilometer-scale) but at a fine vertical scale (meter-scale). There are two types of well data: (1) well logs, corresponding to quasi-continuous (regular sampling) geophysical measurements along the well path (e.g., gamma ray, sonic, neutron porosity), and (2) regions, corresponding to categorical reservoir properties and defined by their top and bottom depths along the well path (e.g., biozones, structural zones, sedimentary facies). Markers are interpreted along the well path and can be associated in order to generate a consistent set of marker associations called well correlations. These well correlations may be generated manually (deterministic approach) by experts, but this may be prone to biases and does not ensure reproducibility. Well correlations may also be generated automatically (deterministic or probabilistic approach) by computing with an algorithm a large number of consistent well correlations and by ranking these realizations according to their likelihood. The likelihood of these computer-assisted well correlations are directly linked to the principle of correlation used to associate markers. This work introduces two principles of correlation, which tend to reproduce the chronostratigraphy and the depositional processes at the parasequence scale: (1) "a marker (described by facies and distality taken at the center of an interval having a constant facies and a constant distality) cannot be associated with another marker described by a depositionally deeper facies at a more proximal position, or a depositionally shallower facies at a more distal position", and (2) "the lower the difference between a chronostratigraphic interpolation (in between markers) and a conceptual depositional profile, the higher the likelihood of the marker association". These two principles of correlation are first benchmarked with analytical solutions and applied on synthetic cases. They have then been used (1) to predict the connectivity of stratigraphic units from well data without strong knowledge on depositional environments by inferring the correlation parameters, or (2) to evaluate the likelihood of a hypothetical depositional environment by generating stochastic realizations and assessing the uncertainties. The methods are applied on a siliciclastic coastal deltaic system targeting a Middle Jurassic reservoir in the South Viking Graben in the North Sea.This work enables (1) to define two specific principles of correlation defined by a few parameters that can be used to generate stochastically well correlations within coastal deltaic systems, and (2) to open the path towards a simple combination of specific principles of correlation to obtain a better characterization of coastal deltaic systems by assessing the uncertainties
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Venturi, Linda. "Etude des propriétés de photoluminescence de nano-matériaux sous champ électrique intense." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR118.
Анотація:
Dans cette thèse, la tomographie à sonde atomique assistée par laser est couplée in situ à un banc de photoluminescence (PL), où le rayonnement laser pulsé est utilize pour déclencher l’évaporation ionique des échantillons et, simultanément, pour activer l’émission à partir des centres optiquement actifs présents dans le matériau. Pour ce travail, deux matériaux différents ont été sélectionnés : des nano-aiguilles de diamant avec des défauts optiquement actifs intégrés (centres de couleur) et une hétérostructure multi-quantique (MQW) ZnO / (Mg, Zn)O, qui contient des émetteurs quantiques d’épaisseurs différentes. Grâce à cette configuration originale de photoluminescence, l’influence du champ électrique sur la structure fine de certains centres de couleur, noyés dans les nano-aiguilles de diamant, a été observée. La première étude s’est concentrée sur le centre neutre de vacance d’azote (NV0), qui est l’un des centres de couleur les plus étudiés dans la littérature. L’évolution de la signature optique NV0, en fonction du biais appliqué, a permis d’évaluer la contrainte mécanique (> 1 GPa) et le champ électrique agissant sur les pointes de diamant. Ces résultats démontrent une nouvelle méthode originale pour effectuer la piezo-spectroscopie sans contact des systems nanométriques sous une contrainte de traction uniaxiale, générée par le champ électrique. Cette méthode a également été appliquée à un autre centre de couleur, dont la nature n’est toujours pas claire dans la littérature, émettant à 2,65 eV, et plus sensible que les centres de couleur NV0 au champ de contrainte / déformation. Des nouveaux résultats sur ses propriétés opto-mécaniques ont été obtenus, mais son identité reste à comprendre. Le champ d’évaporation du diamant étant très élevé, les nano-aiguilles de diamant n’ont pas été analysées à l’aide de La-APT. Par conséquent, la technique couplée in situ a été appliquée afin d’étudier l’hétérostructure ZnO / (Mg, Zn) O MQW, en accédant à la structure, à la composition et à la signature optique de l’échantillon sondé dans une seule expérience. Les spectres de photoluminescence acquis par le spécimen au cours de son évaporation en cours représentent une source unique d’informations pour la compréhension du mécanisme de l’interaction lumière-matière et la physique de la photoémission sous champ électrique élevé. La corrélation des informations structurelles et optiques, liées à cette hétérostructure MQW, démontre que la technique couplée in situ peut chevaucher la limite de diffraction du laser PL et que, comme pour les nano-aiguilles de diamant, il est possible d’estimer le stress de traction induit. Les résultats obtenus par couplage in situ de la technique La-APT avec la spectroscopie PL montrent qu’un tel instrument est une technique innovante et puissante pour effectuer des recherches à l’échelle nanométrique. Pour cette raison, ce travail peut ouvrir de nouvelles perspectives pour une compréhension approfondie de la physique liée aux systèmes étudiés en parallèle avec l’amélioration continue de la configuration expérimentaleIn this thesis, the Laser-assisted Atom Probe Tomography is coupled in-situ with a photoluminescence (PL) bench, where the pulsed laser radiation is used to trigger the ion evaporation from the specimens and, simultaneously, to activate the emission from optically active centers present into the material. For this work, two different materials were selected: diamond nano-needles with embed- ded optically active defects (color centers) and a ZnO/(Mg,Zn)O multi-quantum-well (MQW) heterostructure, which contains quantum emitters of different thicknesses. Thanks to this original photoluminescence setup, the influence of the electric field on the fine structure of some color centers, embedded into the diamond nanoneedles, was observed. The first study focused on the neutral nitrogen-vacancy center (NV0), which is one among the most studied color centers in literature. The evolution of the NV0 optical signature, as a function of the applied bias, allowed to evaluate the mechanical stress (> 1 GPa) and the electric-field acting on diamond tips. These results demon- strate an original new method to perform contactless piezo-spectroscopy of nanoscale systems under uniaxial tensile stress, generated by the electric field. This method was applied also on another color center, which nature is still not clear in literature, emitting at 2.65 eV, and more sensitive than the NV0 color centers to the stress/strain field. New results on its opto-mechanical properties were obtained, but its identity still needs to be understood. Since the evaporation field of diamond is really high, the diamond nanoneedles were not analyzed using La-APT. Therefore the coupled in-situ technique was applied in order to study the ZnO/(Mg,Zn)O MQW heterostructure, accessing to the structure, composition and optical signature of the probed specimen in only one experiment. The photoluminescence spectra acquired by the specimen during its ongoing evaporation represents a unique source of information for the understanding of the mechanism of light-matter interaction and the physics of photoemission under high electric field. The correlation of the structural and optical information, related to this MQW heterostructure, demonstrates that the coupled in-situ technique can overlap the diffraction limit of the PL laser and that, as done for the diamond nanoneedles, is pos- sible to estimate the induced-tensile-stress. The results achieved by the in-situ coupling of the La-APT technique with the PL spec- troscopy show that such instrument is an innovative and powerful technique to perform research at the nanometric scale. For this reason, this work can open new perspectives for a deeply understanding of the physicics related to the studied systems in parallel with the continuous enhancement of the experimental setup
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Su, Bo-Chang, and 蘇柏菖. "Study on the correlation between microstructures and cathodoluminescence of the AlGaInN/AlGaN multi-quantum well LED." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/95611340361129914080.
Анотація:
碩士國立中山大學
物理學系研究所
92
The spectral range of quaternary AlGaInN/AlGaN MQWs extends from UV to IR. Nitride-based green and blue LEDs reveal a high efficiency for the further application. Integrating LEDs of three element colors can perform white light. The optical properties of GaN MQWs are very sensitive to the growth conditions of MQWs. The ununiformity is not fabrication desired but needs to prevent, which is necessary to understand and to precisely control through its growth condition for manufacture the LED. In this work the sample has a luminescence varied from orange to purple across the whole wafer. In this work, the correlations between optical and structural properties in these samples have been studied by means of Transmission Electron Microscopy (TEM), energy dispersive X-ray spectrometry (EDS), and cathodoluminescence (CL) measurements.
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Jarvis, Thomas William. "Novel tools for ultrafast spectroscopy." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-12-4456.
Анотація:
Exciton dynamics in semiconductor nanostructures are dominated by the effects of many-body physics. The application of coherent spectroscopic tools, such as two-dimensional Fourier transform spectroscopy (2dFTS), to the study of these systems can reveal signatures of these effects, and in combination with sophisticated theoretical modeling, can lead to more complete understanding of the behaviour of these systems.
2dFTS has previously been applied to the study of GaAs quantum well samples. In this thesis, we outline a precis of the technique before describing our own experiments using 2dFTS in a partially collinear geometry. This geometry has previously been used to study chemical systems, but we believe these experiments to be the first such performed on semiconductor samples. We extend this technique to a reflection mode 2dFTS experiment, which we believe to be the first such measurement.
In order to extend the techniques of coherent spectroscopy to structured systems, we construct an experimental apparatus that permits us to control the beam geometry used to perform four-wave mixing reflection measurements. To isolate extremely weak signals from intense background fields, we extend a conventional lock-in detection scheme to one that treats the optical fields exciting the sample on an unequal footing. To the best of our knowledge, these measurements represent a novel spectroscopic tool that has not previously been described.text
Книги з теми "Multi-Well correlations":
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Zucker, Robert A., and Sandra A. Brown, eds. The Oxford Handbook of Adolescent Substance Abuse. Oxford University Press, 2015. http://dx.doi.org/10.1093/oxfordhb/9780199735662.001.0001.
Анотація:
This Handbook explores the origins, development, and course of substance use as it emerges and unfolds in adolescence. Given the large causal network involved in adolescent substance use and abuse as well as its powerful impact, both at the time of use and in terms of the long term outcomes and complications of use, the domains covered by this volume range from infancy to adulthood, and from molecular genetics to social policy. The book is organized into eight sections, beginning with a review of the conceptual framework. It explains why a developmental framework is essential in understanding the adolescent period and goes on to discuss the epidemiology of substance use and abuse. It then examines the similarities and differences among the different drugs of abuse, namely: nicotine, alcohol, marijuana, prescription drugs, and other illicit drugs. The remaining sections deal with etiology and course in the context of adolescent development; the correlation between developmental tasks and adolescent substance abuse; clinical symptomatology and comorbidity; and the different assessment and intervention methods that have been developed to address the problem of adolescent alcohol and other drug abuse. These interventions include targeted prevention approaches, family-based treatments, twelve-step approaches, and inpatient and outpatient models. The book concludes with a chapter that analyzes the multi-level structure of public policy for the prevention of alcohol, tobacco, and drug problems among the youth.
Частини книг з теми "Multi-Well correlations":
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Lorenzi, Marco, Marie Deprez, Irene Balelli, Ana L. Aguila, and Andre Altmann. "Integration of Multimodal Data." In Machine Learning for Brain Disorders, 573–97. New York, NY: Springer US, 2012. http://dx.doi.org/10.1007/978-1-0716-3195-9_19.
Анотація:
AbstractThis chapter focuses on the joint modeling of heterogeneous information, such as imaging, clinical, and biological data. This kind of problem requires to generalize classical uni- and multivariate association models to account for complex data structure and interactions, as well as high data dimensionality.Typical approaches are essentially based on the identification of latent modes of maximal statistical association between different sets of features and ultimately allow to identify joint patterns of variations between different data modalities, as well as to predict a target modality conditioned on the available ones. This rationale can be extended to account for several data modalities jointly, to define multi-view, or multi-channel, representation of multiple modalities. This chapter covers both classical approaches such as partial least squares (PLS) and canonical correlation analysis (CCA), along with most recent advances based on multi-channel variational autoencoders. Specific attention is here devoted to the problem of interpretability and generalization of such high-dimensional models. These methods are illustrated in different medical imaging applications, and in the joint analysis of imaging and non-imaging information, such as -omics or clinical data.
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Jiang, Zhonglian, Xiao Chu, Zhen Yu, Jianqun Guo, and Xiumin Chu. "Technical Status Evaluation of River Training Works Based on the Improved DS Evidence Theory." In Lecture Notes in Civil Engineering, 1565–76. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-6138-0_138.
Анотація:
AbstractA large number of river training works have been built in the inland waterway regulation projects to improve ship navigation conditions. However, water damages to river training works happen frequently in practice. Technical status evaluation of river training works is regarded as a fundamental content of inland waterway maintenance. Due to the various influencing factors and complex mechanisms, the content involved in the standard files is recognized as qualitative and no quantitative evaluation method is recommended so far. The technical status of river training works is currently evaluated through on-site investigation which is time-consuming and individual-dependent. By means of multi-source sensors, massive status data of river training works could be obtained instantaneously. Study on the technical evaluation model based on the multi-source information fusion theory attracts more attention in recent years. The classical DS evidence theory could fail as evidence conflict occurs. Thus, the Pearson’s correlation coefficient is calculated and utilized to update the probability distribution in the present study. A novel technical status evaluation model based on the improved DS evidence theory is established. The model is further verified through three case studies of traditional river training works (spur dike and flexible mattress belt) in the Yangtze River, China. The model outputs are consistent with the technical survey reports as well as the published research article. Quantitative and accurate evaluation of river training works could be accomplished by applying the proposed evaluation model. Moreover, the model could be embedded in the Inland Electronic Chart Display and Information System. The present study would provide theoretical basis for inland waterway maintenance and infrastructure monitoring in the future.
3
Qiu, Waishan, Wenjing Li, Xun Liu, and Xiaokai Huang. "Subjectively Measured Streetscape Qualities for Shanghai with Large-Scale Application of Computer Vision and Machine Learning." In Proceedings of the 2021 DigitalFUTURES, 242–51. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-5983-6_23.
Анотація:
AbstractRecently, many new studies emerged to apply computer vision (CV) to street view imagery (SVI) dataset to objectively extract the view indices of various streetscape features such as trees to proxy urban scene qualities. However, human perceptions (e.g., imageability) have a subtle relationship to visual elements which cannot be fully captured using view indices. Conversely, subjective measures using survey and interview data explain more human behaviors. However, the effectiveness of integrating subjective measures with SVI dataset has been less discussed. To address this, we integrated crowdsourcing, CV, and machine learning (ML) to subjectively measure four important perceptions suggested by classical urban design theory. We first collected experts’ rating on sample SVIs regarding the four qualities which became the training labels. CV segmentation was applied to SVI samples extracting streetscape view indices as the explanatory variables. We then trained ML models and achieved high accuracy in predicting the scores. We found a strong correlation between predicted complexity score and the density of urban amenities and services Point of Interests (POI), which validates the effectiveness of subjective measures. In addition, to test the generalizability of the proposed framework as well as to inform urban renewal strategies, we compared the measured qualities in Pudong to other five renowned urban cores worldwide. Rather than predicting perceptual scores directly from generic image features using convolution neural network, our approach follows what urban design theory suggested and confirms various streetscape features affecting multi-dimensional human perceptions. Therefore, its result provides more interpretable and actionable implications for policymakers and city planners.
4
Li, Qingwei, Zhiyong Liu, Lijie Du, Dan Zhang, Yalei Yang, Shan Su, Xiangbo Zhao, and Zhichong Qi. "Prediction Method of the Boreability and Performance for Hard Rock TBM Tunnel." In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220922.
Анотація:
TBM boreability and performance prediction has always been a hot research topic. In this paper, taking one large diameter long tunnel excavated by a gripper hard rock TBM in Northeastern China as research background, based on a large number of boring data on site and mono-factorial regression analysis of the correlations among Field Penetration Index (FPI) and geological parameters, a multi-factorial regression correlation formula of FPI with rock uniaxial compressive strength (UCS) and rock mass integrity coefficient (Kv) was established. Furthermore, the regression correlation formula of TBM penetration (P) with FPI and the formula of thrust (F) with FPI were given. And a classification method of TBM tunnel surrounding rock based on FPI was proposed. Therefore, according to the above formulae, the analysis of boreability, the calculations of TBM penetration, advance rate and the required thrust, and the classification of rock mass can be performed, which provide a theoretical method for the estimation of TBM boreability, performance prediction, specifications design as well as the project planning and duration-cost analysis.
5
Gautam, Anshul, and Christian Hilty. "Fast 2D NMR and Hyperpolarization." In Fast 2D Solution-state NMR, 347–76. The Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/bk9781839168062-00347.
Анотація:
This chapter presents an overview of both the methodology and applications of fast two-dimensional (2D) NMR using nuclear spin hyperpolarization. Fast 2D NMR methods extend the information available from NMR experiments through spin correlations while allowing the utilization of large signals from hyperpolarized spins for the study of fast processes. Hyperpolarization methods typically provide orders of magnitude in NMR signal enhancement. In many cases, however, the mechanism of generating hyperpolarization imposes a technical limit on the number of repetitions of an experiment. Conventional multi-dimensional NMR methods, which rely on re-polarization of spins between each scan, are therefore not directly applicable. Two-dimensional or pseudo 2D NMR experiments can nevertheless be implemented using specific techniques such as ultrafast pulsed-field gradient encoding, sequential scanning with scan-to-scan preservation of spin polarization, or off-resonance decoupling. Intermolecular or intramolecular spin polarization transfer and the observation of correlations between reactants and products can be integrated into these experiments. These and other techniques can be used for the determination of mechanisms in fast chemical reactions or the elucidation of molecular interactions. Applications targeting small molecules, as well as biological macromolecules, protein structure, and protein folding, have been demonstrated.
6
Cao, Yushi, Yanran Li, Yon Shin Teo, Yan Zheng, Zhexin Liang, and Shang-Wei Lin. "An Automatic Test Plan Generation Approach for Automotive Software Testing." In Frontiers in Artificial Intelligence and Applications. IOS Press, 2023. http://dx.doi.org/10.3233/faia230220.
Анотація:
The automotive industry is shifting from hardware-centric to software-centric with the emergence of various intelligent features powered by software. This poses a new challenge for software testers to ensure software reliability by designing test plans that satisfy the test objectives while abiding by the constraints like scope, time, as well as various automotive safety standards. This paper proposed an automatic test plan generation framework built on the evolutionary algorithm. A novel encoding mechanism is proposed to represent the multi-dimensional test plan, while a belief model is proposed to reveal the underlying correlations between the relevant test attributes. Experiments conducted on an actual automotive software in production environment developed by our industry partner show that our method can achieve around 50% improvements in finding defects and covering high-priority test cases as compared to typical evolutionary algorithms while abiding by multiple constraints such as the total run time and custom objectives set by users.
7
Cai, Tianxing. "Application of Biologically Inspired Techniques for Industrial and Environmental Research via Air Quality Monitoring Network." In Advances in Data Mining and Database Management, 272–98. IGI Global, 2014. http://dx.doi.org/10.4018/978-1-4666-6078-6.ch013.
Анотація:
Industrial and environmental research will always involve the study of the cause-effect relationship between the emissions and the surrounding environment. Qualitative and mixed methods researchers have employed a variety of Information and Communication Technology (ICT) tools, simulated or virtual environments, information systems, information devices, and data analysis tools in this field. Machine-enhanced analytics has enabled the identification of aspects of interest such as correlations and anomalies from large datasets. Chemical facilities have high risks to originate air emission events. Based on an available air-quality monitoring network, the data integration technologies are applied to identify the scenarios of the possible emission source and the dynamic pollutant monitor result, so as to timely and effectively support diagnostic and prognostic decisions. In this chapter, the application of artificial neural networks for such applications have been developed according to the real application purpose. It includes two stages of modeling and optimization work: 1) the determination of background normal emission rates from multiple emission sources and 2) single-objective or multi-objective optimization for impact scenario identification and quantification. They have the capability to identify the potential emission profile and spatial-temporal characterization of pollutant dispersion for a specific region, including reverse estimation of the air quality issues. The methodology provides valuable information for accidental investigations and root cause analysis for an emission event; meanwhile, it helps evaluate the regional air quality impact caused by such an emission event as well. Case studies are employed to demonstrate the efficacy of the developed methodology.
8
Kirişci, Murat. "Novel Multi-Attribute Group-Decision Making Method with TOPSIS: A Fermatean Fuzzy Hypersoft Sets and Correlation Coefficients Approach." In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde221119.
Анотація:
One goal of this research is to provide Fermatean fuzzy hypersoft sets and investigate their basic properties. The second goal of this research is to develop the concept and properties of the correlation coefficient and weighted correlation coefficient for the Fermatean fuzzy hypersoft set, as well as to introduce aggregation operators such as the Fermatean fuzzy hypersoft weighted average and Fermatean fuzzy hypersoft weighted geometric operators in the Fermatean fuzzy hypersoft set scenario. A prioritization technique for order preference by similarity to the ideal solution (TOPSIS) is presented using correlation coefficients and weighted correlation coefficients in a Fermatean fuzzy hypersoft set. A technique for solving the multi-attribute group decision-making problem is planned using the developed methodology. In addition, examples of medical decision-making are presented to demonstrate the importance and application of the developed methodology.
9
Kivle, Ineta. "Skaitļu polifonija: imitācija vai simulācija? 111111111 × 111111111 = 12345678987654321." In Izmērītais laiks un telpa, 15–24. LU Akadēmiskais apgāds, 2022. http://dx.doi.org/10.22364/ilt.22.02.
Анотація:
Number relates to intelligible reality: it gives a clear reference to quantity and demonstrates how mind is connected with sensitive world, or how numbers simulate self-referential codes and signs. Numbers as metaphysical order, element of ontological structures, measure of harmony, movement and transformation are applicable for comparison of various philosophical approaches. Philosophical approach seeks abstract and universal being of numbers that connotes with ideas, shapes, and forms – the number always is something definite. On the one hand, numbers are independent of capacities of subjective mind, whereas on the other, numbers are constituted by human mind as a measure of order, proportion, harmony, quantity, etc. As the main philosophical characterizations of number are considered the stances permeating all spectrum of human activities, elucidating functions of being and justifying rational order of the world, as well as constructed realities – simulacrum, hyperreality, digital world, etc. Simulation, as well as imitation relates to reality in different ways, it depends on what is thought by reality. Reality as being of actual existence always changes its horizons from real objects to images and words, from intellect and emotions to signs and images, from signs to signs, etc. Faculty of ancient cosmos to be imitated is not more real than hyperreality with its functions of simulation – they both are realities of philosophical environments of different cultures. The main difference between imitation and simulation confirms existence of two realities: one is concerned with human’s activities that imitate nature, cosmos and other peoples and make references from intelligible to sensitive, from perceptual world to intelligible; another is hyperreality with its own realm that is without references to real human life and activities. Ancient philosophy concerns several aspects of number from cosmic dimensions to sensitive and calculative world, reaching different realms of human activities – democracy and politics, music, harmony of spheres, sounds, rhythm, relationship between cosmos, music and mathematics, etc. Baudrillard creates a new condition of society that have no ground – that is hyperreality, simulacra determined by the force of the code of numeral correlations. Baudrillard gives the examples of consumer objects as codes and shows how one numeral correlation of signs is constituted by structural relations with other signs. Self-referentiality of signs stimulates a separation from real objects, coding systems manage society through signs and digital logic of code. Signs simulate signs, numbers simulate numeral codes – in such flux of data, the subjectivity of human is deconstructed. The concept of number shows two different models of society: one is hypostatic – coming upwards and downwards with a reference to another reality and respect to corresponding truth; the other is a horizontally generated multiplicity – the deconstruction of the real into details without references to another reality and rejection of corresponding truth. However, there is a common stance: Ancient Cosmos as well as Hyperreality are created exploring typical mathematical operations, where numbers justify stability and clear order of created realities. The question is: how do we see numbers in reality? The “polyphony of numbers” works differently in each of these realities. The generally accepted definition that polyphony forms a complex and multi-layered simultaneous process of different components applies equally to the imitation and simulation of numbers, as well as to ancient philosophy and postmodern theories of hyperreality. The difference is in the direction, sequence and understanding of polyphonic reality. The polyphony of numbers explains not only the realities of thoughts that can be separated in historical time, but also the different manifestations of numbers in sounds, colours, and objects. The primary resources of the study are Plato’ dialogues; Plotinus. The Enneads. Tractate On Number; Jean Baudrillard. Simulacra and Simulations.
10
Boothroyd, Andrew T. "Nuclear Scattering." In Principles of Neutron Scattering from Condensed Matter, 127–84. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198862314.003.0005.
Анотація:
This chapter contains an overview of the different types of structural dynamics found in condensed matter, and the associated neutron scattering cross-sections. The scattering dynamics of the harmonic oscillator is discussed, and an expression for the Debye-Waller factor is obtained. In the case of crystalline solids, the vibrational spectrum in the harmonic approximation is described, including the phonon dispersion and the cross-sections for one-phonon coherent and incoherent scattering. Multi-phonon scattering is discussed briefly. For non-crystalline matter, the time-dependent van Hove correlation and response functions are introduced, and their relation to the scattering cross-section established. An approximate expression for the correlation function is obtained from the classical form. Partial correlation and response functions are defined for multicomponent systems. The technique of neutron Compton scattering as a probe of single-particle recoil dynamics is described. Quasielastic and neutron spin-echo spectroscopy are introduced, as well as examples of relaxational dynamics which these techniques can measure.
Тези доповідей конференцій з теми "Multi-Well correlations":
1
Zhang, Qian-Wen, Ximing Zhang, Zhao Yan, Ruifang Liu, Yunbo Cao, and Min-Ling Zhang. "Correlation-Guided Representation for Multi-Label Text Classification." In Thirtieth International Joint Conference on Artificial Intelligence {IJCAI-21}. California: International Joint Conferences on Artificial Intelligence Organization, 2021. http://dx.doi.org/10.24963/ijcai.2021/463.
Анотація:
Multi-label text classification is an essential task in natural language processing. Existing multi-label classification models generally consider labels as categorical variables and ignore the exploitation of label semantics. In this paper, we view the task as a correlation-guided text representation problem: an attention-based two-step framework is proposed to integrate text information and label semantics by jointly learning words and labels in the same space. In this way, we aim to capture high-order label-label correlations as well as context-label correlations. Specifically, the proposed approach works by learning token-level representations of words and labels globally through a multi-layer Transformer and constructing an attention vector through word-label correlation matrix to generate the text representation. It ensures that relevant words receive higher weights than irrelevant words and thus directly optimizes the classification performance. Extensive experiments over benchmark multi-label datasets clearly validate the effectiveness of the proposed approach, and further analysis demonstrates that it is competitive in both predicting low-frequency labels and convergence speed.
2
Han, Kai, Yunhe Wang, Han Shu, Chuanjian Liu, Chunjing Xu, and Chang Xu. "Attribute Aware Pooling for Pedestrian Attribute Recognition." In Twenty-Eighth International Joint Conference on Artificial Intelligence {IJCAI-19}. California: International Joint Conferences on Artificial Intelligence Organization, 2019. http://dx.doi.org/10.24963/ijcai.2019/341.
Анотація:
This paper expands the strength of deep convolutional neural networks (CNNs) to the pedestrian attribute recognition problem by devising a novel attribute aware pooling algorithm. Existing vanilla CNNs cannot be straightforwardly applied to handle multi-attribute data because of the larger label space as well as the attribute entanglement and correlations. We tackle these challenges that hampers the development of CNNs for multi-attribute classification by fully exploiting the correlation between different attributes. The multi-branch architecture is adopted for fucusing on attributes at different regions. Besides the prediction based on each branch itself, context information of each branch are employed for decision as well. The attribute aware pooling is developed to integrate both kinds of information. Therefore, attributes which are indistinct or tangled with others can be accurately recognized by exploiting the context information. Experiments on benchmark datasets demonstrate that the proposed pooling method appropriately explores and exploits the correlations between attributes for the pedestrian attribute recognition.
3
Bai, Junwen, Shufeng Kong, and Carla Gomes. "Disentangled Variational Autoencoder based Multi-Label Classification with Covariance-Aware Multivariate Probit Model." In Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. California: International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/595.
Анотація:
Multi-label classification is the challenging task of predicting the presence and absence of multiple targets, involving representation learning and label correlation modeling. We propose a novel framework for multi-label classification, Multivariate Probit Variational AutoEncoder (MPVAE), that effectively learns latent embedding spaces as well as label correlations. MPVAE learns and aligns two probabilistic embedding spaces for labels and features respectively. The decoder of MPVAE takes in the samples from the embedding spaces and models the joint distribution of output targets under a Multivariate Probit model by learning a shared covariance matrix. We show that MPVAE outperforms the existing state-of-the-art methods on important computational sustainability applications as well as on other application domains, using public real-world datasets. MPVAE is further shown to remain robust under noisy settings. Lastly, we demonstrate the interpretability of the learned covariance by a case study on a bird observation dataset.
4
Xiong, Hongjie, Sangcheol Yoon, and Yu Jiang. "A Novel Method to Speedup Calibrating Horizontal Well Performance Model with Multi-Stage Fracturing Treatments and Its Applications in Delaware Basin." In SPE Reservoir Simulation Conference. SPE, 2021. http://dx.doi.org/10.2118/203935-ms.
Анотація:
Abstract The multi-stage fracture treatments create complex fracture networks with various proppant type, size, and concentration distributed within and along fractures through reservoir rock, where larger size and higher concentrations usually result in higher long-term conductivity. To model the fracture conductivity reduction with depletion, we traditionally use a single monotonic relationship between fracture conductivity and pressure, which is proper for a single proppant concentration but obviously hard to describe the situation in the horizontal wells with complex concentration distributions. This paper is to present a new method to speed-up the calibration process of well performance models with multi-million cells and its two applications in the Wolfcamp reservoir in the Delaware Basin. To study well performance and completion effectiveness of 3000 horizontal wells over University Lands acreage in the Permian Basin, we have built a series of well performance models with complex fracture networks (SPE 189855 and 194367). We have used those models to methodically investigate the drivers of well completion parameters and well spacing on well performance and field development value (URTeC 554). In the process of building multiple robust well performance models, we found out it is hard and time-consuming to calibrate a well performance model with multi-million cells based upon a single correlation between fracture conductivity and pressure. We first modeled the complex fracture networks and fracture conductivity distributions based upon the historical completion pumping data; we then developed multiple correlations to characterize fracture conductivity reduction and closure behaviors with pressure depletion based upon initial fracture conductivities (as the result of proppant type, size, and concentration) and reservoir geomechanical properties. We found out that this method significantly reduced our model calibration time. We then applied our method to multiple case studies in the Permian Basin to test and improve the method. We have thus developed a method to mimic the fracture conductivity reduction and closure behavior in the horizontal wells with complex fracture networks. The paper will layout the theoretical foundation and detail our method to develop the multiple correlations to model fracture conductivity reduction and fracture closure behaviors in the horizontal well performance models in the unconventional reservoirs. We will then show two case studies to illustrate how we have applied our method to speed up the model calibration process. Based upon the multiple applications into our model calibration process, we have concluded that the method is very effective to calibrate the well performance model with complex fracture networks. The method can be used for engineers to simplify and speedup calibrating horizontal well performance models. Therefore, engineers can more effectively build more robust well performance models to optimize field development plans in the unconventional reservoirs.
5
Cottin, Guillaume, Emmanuel Laroche, Nicolas Savary, and Pierre Millan. "Modeling of the Heat Flux for Multi-Hole Cooling Applications." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46330.
Анотація:
The aims of this work are to achieve a better understanding of thermal fluxes around a multi-perforated plate and obtain correlations for heat transfer coefficient on the hot as well as cold side and in a perforation. A 3-dimensional, RANS, conjugate simulation and an adiabatic one are performed for different aerothermal conditions already studied experimentally. Convective heat flux, wall temperature and adiabatic temperature are averaged on a periodic pattern around each hole. A mean heat transfer coefficient is calculated based on these quantities and correlations are deduced for this coefficient. Such results as fluid temperature rise in a perforation or the contribution of flux in the perforations to the whole cooling flux are also given in this article.
6
Hall, Joseph W., Jeremy Pinier, Andre´ Hall, and Mark Glauser. "Two-Point Correlations of the Near and Far-Field Pressure in a Transonic Jet." In ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98458.
Анотація:
To better understand the relationship between the near-field pressure and the acoustic far-field, multi-point measurements of the near-field pressure around the periphery of a cold Mach 0.85 round jet are compared to simultaneous multi-point far-field acoustic pressure measurements. The results indicate that the near-field pressure is low dimensional and the instantaneous contribution from both azimuthal mode 0 and 1 is sufficient to accurately recover the dynamics of the near-field pressure. Correlations of the acoustic far-field with the contribution of each azimuthal mode to the near field pressure, however, indicate that only azimuthal mode 0 is well correlated with the far-field pressure, suggesting that the acoustic source in the jet is predominantly axisymmetric. The correlation of the higher azimuthal pressure modes with the far-field acoustic pressure is extremely poor suggesting that the axisymmetric source is weakened by the presence of higher azimuthal modes in the near field of the jet.
7
Yan, Yan, and Gregory S. Chirikjian. "Molecular Replacement for Multi-Domain Structures Using Packing Models." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-48583.
Анотація:
Molecular replacement (MR) is frequently used to obtain phase information for a unit cell packed with a macromolecule of unknown structure. The goal of MR searches is to place a homologous/similar molecule in the unit cell so as to maximize the correlation with x-ray diffraction data. MR software packages typically perform rotation and translation searches separately. This works quite well for single-domain proteins. However, for multi-domain structures and complexes, computational requirements can become prohibitive and the desired peaks can become hidden in a noisy landscape. The main contribution of our approach is that computationally expensive MR searches in continuous configuration space are replaced by a search on a relatively small discrete set of candidate packing arrangements of a multi-rigid-body model. These candidate arrangements are generated by collision detections on a coarse grid in the configuration space first. The list of feasible arrangements is short because packing constraints together with unit cell symmetry and geometry impose strong constraints. After computing Patterson correlations of the collision-free arrangements, an even shorter list can be obtained using the 10 candidates with highest correlations. In numerical trials, we found that a candidate from the feasible set is usually similar to the arrangement of the target structure within the unit cell. To further improve the accuracy, a Rapidly-exploring Random Tree (RRT) can be applied in the neighborhood of this packing arrangement. Our approach is demonstrated with multi-domain models in silico for 3D, with ellipsoids representing both the domains of the model and target structures. Configurations are defined by sets of angles between the ellipsoids. Our results show that an approximate configuration can be found with mean absolute error (MAE) less than 5 degrees.
8
Li, Ruihuang, Changqing Zhang, Qinghua Hu, Pengfei Zhu, and Zheng Wang. "Flexible Multi-View Representation Learning for Subspace Clustering." In Twenty-Eighth International Joint Conference on Artificial Intelligence {IJCAI-19}. California: International Joint Conferences on Artificial Intelligence Organization, 2019. http://dx.doi.org/10.24963/ijcai.2019/404.
Анотація:
In recent years, numerous multi-view subspace clustering methods have been proposed to exploit the complementary information from multiple views. Most of them perform data reconstruction within each single view, which makes the subspace representation unpromising and thus can not well identify the underlying relationships among data. In this paper, we propose to conduct subspace clustering based on Flexible Multi-view Representation (FMR) learning, which avoids using partial information for data reconstruction. The latent representation is flexibly constructed by enforcing it to be close to different views, which implicitly makes it more comprehensive and well-adapted to subspace clustering. With the introduction of kernel dependence measure, the latent representation can flexibly encode complementary information from different views and explore nonlinear, high-order correlations among these views. We employ the Alternating Direction Minimization (ADM) method to solve our problem. Empirical studies on real-world datasets show that our method achieves superior clustering performance over other state-of-the-art methods.
9
Kawahara, Akimaro, Michio Sadatomi, Yutaro Nakamoto, and Takatoshi Masuda. "Study of Interfacial Friction Force for Bubble Flows in a 2×1 Rods Channel Simplifying BWR." In 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-30270.
Анотація:
Most of recent subchannel analysis codes are based on a multi-fluid model, and accurate evaluation of the constitutive equations in the model is essential. In order to get an accurate one of the interfacial friction force in two-phase bubble flows, experimental data on drag coefficient and interfacial area concentration have been obtained for air-water flows in 2×1 rods channel simplifying a BWR fuel rod bundle. In order to know the effects of liquid properties on the data, temperature of the test water was changed from 18 to 50 °C. The data are compared with the existing correlations reported in literatures. As a result, Hibiki and Ishii (2001) semi-theoretical correlation is found to give the best prediction against the present interfacial area concentration data. Delhaye and Bricard (1994) correlation also gives reasonably good prediction if their correlation were modified by incorporating liquid property effects. As for the drag coefficient, no correlation exist which can predict well the present data. Therefore, we developed a new correlation including three dimensionless numbers, i.e., bubble Capillary number, Morton number and Eo¨tvo¨s number. The correlation could predict well Liu et al.’s data (2008) as well as the present data.
10
Heidari, Mohammad, Christopher Istchenko, William Bailey, and Terry Stone. "Use of Horizontal Drift-Flux Models For Simulating Wellbore Flow in SAGD Operations." In SPE Reservoir Simulation Conference. SPE, 2021. http://dx.doi.org/10.2118/203955-ms.
Анотація:
Abstract The paper examines new horizontal drift-flux correlations for their ability to accurately model phase flow rates and pressure drops in horizontal and undulating wells that are part of a Steam-Assisted Gravity Drainage (SAGD) field operation. Pressure profiles within each well correlate to the overall performance of the pair. SAGD is a low-pressure process that is sensitive to reservoir heterogeneity and other factors, hence accurate simulation of in situ wellbore pressures is critical for both mitigating uneven steam chamber evolution and optimizing wellbore design and operation. Recently published horizontal drift-flux correlations have been implemented in a commercial thermal reservoir simulator with a multi-segment well model. Valid for horizontally drilled wells with undulations, they complement previously reported drift-flux models developed for vertical and inclined wells down to approximately 5 degrees from horizontal. The formulation of these correlations has a high degree of nonlinearity. These models are tested in simulations of SAGD field operations. First, an overview of drift-flux models is discussed. This differentiates those based on vertical flow with gravity segregation to those that model horizontal flow with stratified and slug flow regimes. Second, the most recent and significant drift-flux correlation by Bailey et al. (2018, and hereafter referred to as Bailey-Tang-Stone) was robustly designed to be used in the well model of a reservoir simulator, can handle all inclination angles and was optimized to experimental data from the largest available databases to date. This and earlier drift-flux models are reviewed as to their strengths and weaknesses. Third, governing equations and implementation details are given of the Bailey-Tang-Stone model. Fourth, six case studies are presented that illustrate homogeneous and drift-flux flow model differences for various well scenarios.
Звіти організацій з теми "Multi-Well correlations":
1
Ayoul-Guilmard, Q., S. Ganesh, M. Nuñez, R. Tosi, F. Nobile, R. Rossi, and C. Soriano. D5.4 Report on MLMC for time dependent problems. Scipedia, 2021. http://dx.doi.org/10.23967/exaqute.2021.2.005.
Анотація:
In this report, we study the use of Multi-Level Monte Carlo (MLMC) methods for time dependent problems. It was found that the usability of MLMC methods depends strongly on whether or not the underlying time dependent problem is chaotic in nature. Numerical experiments are conducted on both simple problems, as well as fluid flow problems of practical interest to the ExaQUte project, to demonstrate this. For the non-chaotic cases, the hypotheses that enable the use of MLMC methods were found to be satisfied. For the chaotic cases, especially the case of high Reynolds’ number fluid flow, the hypotheses were not satisfied. However, it was found that correlations between the different levels were high enough to merit the use of multi-fidelity or control-variate approaches. It was also noted that MLMC methods could work for chaotic problems if the time window of analysis were chosen to be small enough. Future studies are proposed to examine this possibility.
2
Wideman, Jr., Robert F., Nicholas B. Anthony, Avigdor Cahaner, Alan Shlosberg, Michel Bellaiche, and William B. Roush. Integrated Approach to Evaluating Inherited Predictors of Resistance to Pulmonary Hypertension Syndrome (Ascites) in Fast Growing Broiler Chickens. United States Department of Agriculture, December 2000. http://dx.doi.org/10.32747/2000.7575287.bard.
Анотація:
Background PHS (pulmonary hypertension syndrome, ascites syndrome) is a serious cause of loss in the broiler industry, and is a prime example of an undesirable side effect of successful genetic development that may be deleteriously manifested by factors in the environment of growing broilers. Basically, continuous and pinpointed selection for rapid growth in broilers has led to higher oxygen demand and consequently to more frequent manifestation of an inherent potential cardiopulmonary incapability to sufficiently oxygenate the arterial blood. The multifaceted causes and modifiers of PHS make research into finding solutions to the syndrome a complex and multi threaded challenge. This research used several directions to better understand the development of PHS and to probe possible means of achieving a goal of monitoring and increasing resistance to the syndrome. Research Objectives (1) To evaluate the growth dynamics of individuals within breeding stocks and their correlation with individual susceptibility or resistance to PHS; (2) To compile data on diagnostic indices found in this work to be predictive for PHS, during exposure to experimental protocols known to trigger PHS; (3) To conduct detailed physiological evaluations of cardiopulmonary function in broilers; (4) To compile data on growth dynamics and other diagnostic indices in existing lines selected for susceptibility or resistance to PHS; (5) To integrate growth dynamics and other diagnostic data within appropriate statistical procedures to provide geneticists with predictive indices that characterize resistance or susceptibility to PHS. Revisions In the first year, the US team acquired the costly Peckode weigh platform / individual bird I.D. system that was to provide the continuous (several times each day), automated weighing of birds, for a comprehensive monitoring of growth dynamics. However, data generated were found to be inaccurate and irreproducible, so making its use implausible. Henceforth, weighing was manual, this highly labor intensive work precluding some of the original objectives of using such a strategy of growth dynamics in selection procedures involving thousands of birds. Major conclusions, solutions, achievements 1. Healthy broilers were found to have greater oscillations in growth velocity and acceleration than PHS susceptible birds. This proved the scientific validity of our original hypothesis that such differences occur. 2. Growth rate in the first week is higher in PHS-susceptible than in PHS-resistant chicks. Artificial neural network accurately distinguished differences between the two groups based on growth patterns in this period. 3. In the US, the unilateral pulmonary occlusion technique was used in collaboration with a major broiler breeding company to create a commercial broiler line that is highly resistant to PHS induced by fast growth and low ambient temperatures. 4. In Israel, lines were obtained by genetic selection on PHS mortality after cold exposure in a dam-line population comprising of 85 sire families. The wide range of PHS incidence per family (0-50%), high heritability (about 0.6), and the results in cold challenged progeny, suggested a highly effective and relatively easy means for selection for PHS resistance 5. The best minimally-invasive diagnostic indices for prediction of PHS resistance were found to be oximetry, hematocrit values, heart rate and electrocardiographic (ECG) lead II waves. Some differences in results were found between the US and Israeli teams, probably reflecting genetic differences in the broiler strains used in the two countries. For instance the US team found the S wave amplitude to predict PHS susceptibility well, whereas the Israeli team found the P wave amplitude to be a better valid predictor. 6. Comprehensive physiological studies further increased knowledge on the development of PHS cardiopulmonary characteristics of pre-ascitic birds, pulmonary arterial wedge pressures, hypotension/kidney response, pulmonary hemodynamic responses to vasoactive mediators were all examined in depth. Implications, scientific and agricultural Substantial progress has been made in understanding the genetic and environmental factors involved in PHS, and their interaction. The two teams each successfully developed different selection programs, by surgical means and by divergent selection under cold challenge. Monitoring of the progress and success of the programs was done be using the in-depth estimations that this research engendered on the reliability and value of non-invasive predictive parameters. These findings helped corroborate the validity of practical means to improve PHT resistance by research-based programs of selection.