scholarly journals Physics-Informed Tensor-Train ConvLSTM for Volumetric Velocity Forecasting of the Loop Current

2021 ◽  
Vol 4 ◽  
Author(s):  
Yu Huang ◽  
Yufei Tang ◽  
Hanqi Zhuang ◽  
James VanZwieten ◽  
Laurent Cherubin
Keyword(s):  
Prediction Model ◽  
Function Analysis ◽  
Numerical Models ◽  
Spatial Scales ◽  
Time Frame ◽  
Higher Order ◽  
Multiple Time ◽  
Loop Current ◽  
Predictive Learning ◽  
High Level

According to the National Academies, a week long forecast of velocity, vertical structure, and duration of the Loop Current (LC) and its eddies at a given location is a critical step toward understanding their effects on the gulf ecosystems as well as toward anticipating and mitigating the outcomes of anthropogenic and natural disasters in the Gulf of Mexico (GoM). However, creating such a forecast has remained a challenging problem since LC behavior is dominated by dynamic processes across multiple time and spatial scales not resolved at once by conventional numerical models. In this paper, building on the foundation of spatiotemporal predictive learning in video prediction, we develop a physics informed deep learning based prediction model called—Physics-informed Tensor-train ConvLSTM (PITT-ConvLSTM)—for forecasting 3D geo-spatiotemporal sequences. Specifically, we propose (1) a novel 4D higher-order recurrent neural network with empirical orthogonal function analysis to capture the hidden uncorrelated patterns of each hierarchy, (2) a convolutional tensor-train decomposition to capture higher-order space-time correlations, and (3) a mechanism that incorporates prior physics from domain experts by informing the learning in latent space. The advantage of our proposed approach is clear: constrained by the law of physics, the prediction model simultaneously learns good representations for frame dependencies (both short-term and long-term high-level dependency) and inter-hierarchical relations within each time frame. Experiments on geo-spatiotemporal data collected from the GoM demonstrate that the PITT-ConvLSTM model can successfully forecast the volumetric velocity of the LC and its eddies for a period greater than 1 week.

Investigating patterns of in-channel wood deposition locations in a low-gradient, variably-confined alluvial river system

2018 ◽  
Vol 42 (2) ◽  
pp. 139-161 ◽  
Author(s):  
Derek J Martin ◽  
Carol P Harden ◽  
Liem Tran ◽  
Robert T Pavlowsky
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Statistical Tests ◽  
Spatial Scales ◽  
River System ◽  
Morphological Features ◽  
Periodic Patterns ◽  
Alluvial River ◽  
Morphological Variables ◽  
High Level

In-channel large wood (LW) plays an important role in the eco-morphological functionality of many river systems. This importance has been widely recognized, yet there continues to be a poor understanding of relationships between morphodynamics and locations of wood deposition within the channel, particularly in low-gradient, semi-confined rivers. This research investigates the following hypotheses: 1) LW deposition locations (DLs) occur periodically in relation to the periodic arrangement of morphological features in the Big River, Missouri, USA, a low-gradient, variably-confined, alluvial river system; 2) geomorphic controls on DLs in the Big River exert varying levels of influence at different spatial scales. A large-scale field inventory of LW DLs was performed along the Big River. A spectral analysis was then used to identify periodic patterns of DLs along the Big River and various statistical tests of association were used to investigate the relationships between DLs and morphological variables, and between periodicity (where identified) and morphological variables. The results suggest that under certain circumstances, DLs are spatially periodic, with periodicities ranging from 270 m to 1371 m, and in some cases exhibit periodicity at different spatial scales. Regression analysis was unable to statistically associate periodicity with morphological features; however, correlation and stepwise Poisson regression models suggest that channel-scale (100 m to 500 m) sinuosity, and valley width exert more influence on DLs than other variables. The lack of strong statistical associations suggests that either 1) LW dynamics in the Big River contain a high level of stochasticity or 2) controlling variables were not included in this analysis. These results support the need for better theoretical and numerical models of stochastic LW processes in order to better manage LW in complex geomorphic systems.

The Factor Structure and Psychometric Properties of the Resiliency Scale in Chinese Undergraduates

2010 ◽  
Vol 26 (3) ◽  
pp. 162-171 ◽  
Author(s):  
Lixia Cui ◽  
Xiujie Teng ◽  
Xupei Li ◽  
Tian P.S. Oei
Keyword(s):  
Factor Analysis ◽  
Psychometric Properties ◽  
Factor Structure ◽  
Undergraduate Students ◽  
Concurrent Validity ◽  
Higher Order ◽  
Criterion Variable ◽  
Confirmatory Factor ◽  
High Level ◽  
Chinese Undergraduates

The current study examined the factor structure and the psychometric properties of Sandra Prince-Embury’s Resiliency Scale for Adolescents (RESA) in Chinese undergraduates. A total of 726 undergraduate students were randomly divided into two subsamples: Sample A was used for the exploratory factor analysis (EFA) and Sample B was used for the confirmatory factor analysis (CFA). The EFA revealed that 56 items and a model of 10 factors with 3 higher order factors (as described by Sandra) were to be retained; CFA with Sample B confirmed this result. The overall scale and the subscales of the Chinese-RESA demonstrated a high level of internal consistency. Furthermore, concurrent validity was demonstrated by the correlation of the scale with other instruments such as the PANAS and the CSS, and the predictive validity was confirmed via three multiple regression analyses using the PANAS as a criterion variable: one for the 10 subscales of the C-RESA, one for the 3 higher order scales, and one for the total C-RESA. We concluded that the C-RESA may be used for research into Chinese undergraduates’ adaptive behaviors.

scholarly journals Corrosion of ternary borosilicate glass in acidic solution studied in operando by fluid-cell Raman spectroscopy

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Christoph Lenting ◽  
Thorsten Geisler
Keyword(s):  
Raman Spectroscopy ◽  
Nuclear Waste ◽  
Numerical Models ◽  
Adsorbed Water ◽  
Corrosion Mechanism ◽  
Borosilicate Glasses ◽  
Long Term Storage ◽  
In Operando ◽  
High Level ◽  
Fluid Cell

AbstractFluid-cell Raman spectroscopy is a space and time-resolving application allowing in operando studies of dynamic processes during solution–solid interactions. A currently heavily debated example is the corrosion mechanism of borosilicate glasses, which are the favoured material for the immobilization of high-level nuclear waste. With an upgraded fluid-cell lid design made entirely from the glass sample itself, we present the polymerization of the surface alteration layer over time in an initially acidic environment, including the differentiation between pore and surface-adsorbed water within it. Our results support an interface-coupled dissolution-precipitation model, which opposes traditional ion-exchange models for the corrosion mechanism. A sound description of the corrosion mechanism is essential for reliable numerical models to predict the corrosion rate of nuclear waste glasses during long-term storage in a geological repository.

scholarly journals Are We Doing ‘Systems’ Research? An Assessment of Methods for Climate Change Adaptation to Hydrohazards in a Complex World

2019 ◽  
Vol 11 (4) ◽  
pp. 1163 ◽  
Author(s):  
Melissa Bedinger ◽  
Lindsay Beevers ◽  
Lila Collet ◽  
Annie Visser
Keyword(s):  
Climate Change ◽  
Human Nature ◽  
Climate Change Adaptation ◽  
Time Scales ◽  
Spatial Scales ◽  
Local Context ◽  
Multiple Time Scales ◽  
Future Research ◽  
Multiple Time ◽  
Systems Research

Climate change is a product of the Anthropocene, and the human–nature system in which we live. Effective climate change adaptation requires that we acknowledge this complexity. Theoretical literature on sustainability transitions has highlighted this and called for deeper acknowledgment of systems complexity in our research practices. Are we heeding these calls for ‘systems’ research? We used hydrohazards (floods and droughts) as an example research area to explore this question. We first distilled existing challenges for complex human–nature systems into six central concepts: Uncertainty, multiple spatial scales, multiple time scales, multimethod approaches, human–nature dimensions, and interactions. We then performed a systematic assessment of 737 articles to examine patterns in what methods are used and how these cover the complexity concepts. In general, results showed that many papers do not reference any of the complexity concepts, and no existing approach addresses all six. We used the detailed results to guide advancement from theoretical calls for action to specific next steps. Future research priorities include the development of methods for consideration of multiple hazards; for the study of interactions, particularly in linking the short- to medium-term time scales; to reduce data-intensivity; and to better integrate bottom–up and top–down approaches in a way that connects local context with higher-level decision-making. Overall this paper serves to build a shared conceptualisation of human–nature system complexity, map current practice, and navigate a complexity-smart trajectory for future research.

Enabling social networks in an R&D organization

2006 ◽  
Vol 25 (4) ◽  
pp. 237-246
Author(s):  
Tomas Hellström
Keyword(s):  
Social Networks ◽  
Social Network ◽  
Qualitative Study ◽  
Network Formation ◽  
Higher Order ◽  
Practical Significance ◽  
Administrative Unit ◽  
High Level ◽  
Social Network Formation

This paper presents a qualitative study of mechanisms enabling social network formation in the R&D unit of a large technology-based organization. Drawing on interviews with 37 high-level technical and administrative unit members, a number of social network enablers could be discerned, which related to the need for effective location mechanisms, special “enrolment spaces”, and mechanisms for forging contacts. It was also possible to identify a number of higher-order factors for facilitation of network formation, namely hierarchical enablers and communicative and assimilative factors. Based on these results, the paper makes suggestions as to the theoretical and practical significance of social network enabling mechanisms in R&D organizations.

scholarly journals Scale-dependent intrinsic entropies of complex time series

2016 ◽  
Vol 374 (2065) ◽  
pp. 20150204 ◽  
Author(s):  
Jia-Rong Yeh ◽  
Chung-Kang Peng ◽  
Norden E. Huang
Keyword(s):  
Time Series ◽  
Time Scales ◽  
Spatial Scales ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Complex Time ◽  
Multi Scale ◽  
Mode Decomposition ◽  
Simulated Time ◽  
Simulated Time Series

Multi-scale entropy (MSE) was developed as a measure of complexity for complex time series, and it has been applied widely in recent years. The MSE algorithm is based on the assumption that biological systems possess the ability to adapt and function in an ever-changing environment, and these systems need to operate across multiple temporal and spatial scales, such that their complexity is also multi-scale and hierarchical. Here, we present a systematic approach to apply the empirical mode decomposition algorithm, which can detrend time series on various time scales, prior to analysing a signal’s complexity by measuring the irregularity of its dynamics on multiple time scales. Simulated time series of fractal Gaussian noise and human heartbeat time series were used to study the performance of this new approach. We show that our method can successfully quantify the fractal properties of the simulated time series and can accurately distinguish modulations in human heartbeat time series in health and disease.

scholarly journals Dynamics of Biweekly Oscillations in the Equatorial Indian Ocean*

2006 ◽  
Vol 36 (5) ◽  
pp. 827-846 ◽  
Author(s):  
Toru Miyama ◽  
Julian P. McCreary ◽  
Debasis Sengupta ◽  
Retish Senan
Keyword(s):  
Indian Ocean ◽  
Numerical Models ◽  
Energy Levels ◽  
Vertical Mixing ◽  
Equatorial Indian Ocean ◽  
Higher Order ◽  
Near Surface ◽  
Higher Order Modes ◽  
Model Control ◽  
Quikscat Winds

Abstract Variability of the wind field over the equatorial Indian Ocean is spread throughout the intraseasonal (10–60 day) band. In contrast, variability of the near-surface υ field in the eastern, equatorial ocean is concentrated at biweekly frequencies and is largely composed of Yanai waves. The excitation of this biweekly variability is investigated using an oceanic GCM and both analytic and numerical versions of a linear, continuously stratified (LCS) model in which solutions are represented as expansions in baroclinic modes. Solutions are forced by Quick Scatterometer (QuikSCAT) winds (the model control runs) and by idealized winds having the form of a propagating wave with frequency σ and wavenumber kw. The GCM and LCS control runs are remarkably similar in the biweekly band, indicating that the dynamics of biweekly variability are fundamentally linear and wind driven. The biweekly response is composed of local (nonradiating) and remote (Yanai wave) parts, with the former spread roughly uniformly along the equator and the latter strengthening to the east. Test runs to the numerical models separately forced by the τx and τy components of the QuikSCAT winds demonstrate that both forcings contribute to the biweekly signal, the response forced by τy being somewhat stronger. Without mixing, the analytic spectrum for Yanai waves forced by idealized winds has a narrowband (resonant) response for each baroclinic mode: Spectral peaks occur whenever the wavenumber of the Yanai wave for mode n is sufficiently close to kw and they shift from biweekly to lower frequencies with increasing modenumber n. With mixing, the higher-order modes are damped so that the largest ocean response is restricted to Yanai waves in the biweekly band. Thus, in the LCS model, resonance and mixing act together to account for the ocean's favoring the biweekly band. Because of the GCM's complexity, it cannot be confirmed that vertical mixing also damps its higher-order modes; other possible processes are nonlinear interactions with near-surface currents, and the model's low vertical resolution below the thermocline. Test runs to the LCS model show that Yanai waves from several modes superpose to form a beam (wave packet) that carries energy downward as well as eastward. Reflections of such beams from the near-surface pycnocline and bottom act to maintain near-surface energy levels, accounting for the eastward intensification of the near-surface, equatorial υ field in the control runs.

Expression of the murine homeobox-containing gene Hox-2.3 suggests multiple time-dependent and tissue-specific roles during development

Development ◽  
1990 ◽  
Vol 110 (4) ◽  
pp. 1159-1168 ◽  
Author(s):  
R. Vogels ◽  
W. de Graaff ◽  
J. Deschamps
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Expression Pattern ◽  
Subsequent Development ◽  
Multiple Time ◽  
Urogenital System ◽  
Homeotic Genes ◽  
Lateral Plate ◽  
Tissue Specific ◽  
High Level

This study reports the expression pattern of the murine homeobox-containing gene Hox-2.3 during development. Using in situ hybridization, we first detect Hox-2.3 transcripts in the allantois primordium at 7.5 days post coitum (p.c.). One day later transcripts are found in embryonic ectoderm and mesoderm. In 9.5- and 10.5- day embryos Hox-2.3 expression is observed in the central nervous system (CNS) from a rostral boundary in the upper spinal cord to the caudal end. Within this anteroposterior domain, Hox-2.3 expression is also found in the peripheral nervous system, in the mesoderm and in the hindgut epithelium. The rostral boundary in the mesoderm is located at the level of the 11th somite and thus shifted posteriorwards compared to the rostral boundary in the neural tube. During subsequent development, the initially broad expression pattern in the somitic, lateral plate and intermediate mesoderm becomes restricted to structures in the urogenital system. In adults, the spinal cord and the derivatives of the Wolffian and Mullerian ducts continue to express the gene at a high level. The described temporal and tissue-specific changes in expression of Hox-2.3 are suggestive of several levels of regulation as reported for Drosophila homeotic genes and argue for more than one role of the gene during development and in adults.

scholarly journals Evaluation of numerical models by FerryBox and fixed platform in situ data in the southern North Sea

Ocean Science ◽  
2015 ◽  
Vol 11 (6) ◽  
pp. 879-896 ◽  
Author(s):  
M. Haller ◽  
F. Janssen ◽  
J. Siddorn ◽  
W. Petersen ◽  
S. Dick
Keyword(s):  
North Sea ◽  
High Frequency ◽  
Numerical Models ◽  
Spatial Scales ◽  
Model Performance ◽  
Eastern Coast ◽  
Southern North Sea ◽  
In Situ Data ◽  
Oyster Ground ◽  
Study Results

Abstract. For understanding and forecasting of hydrodynamics in coastal regions, numerical models have served as an important tool for many years. In order to assess the model performance, we compared simulations to observational data of water temperature and salinity. Observations were available from FerryBox transects in the southern North Sea and, additionally, from a fixed platform of the MARNET network. More detailed analyses have been made at three different stations, located off the English eastern coast, at the Oyster Ground and in the German Bight. FerryBoxes installed on ships of opportunity (SoO) provide high-frequency surface measurements along selected tracks on a regular basis. The results of two operational hydrodynamic models have been evaluated for two different time periods: BSHcmod v4 (January 2009 to April 2012) and FOAM AMM7 NEMO (April 2011 to April 2012). While they adequately simulate temperature, both models underestimate salinity, especially near the coast in the southern North Sea. Statistical errors differ between the two models and between the measured parameters. The root mean square error (RMSE) of water temperatures amounts to 0.72 °C (BSHcmod v4) and 0.44 °C (AMM7), while for salinity the performance of BSHcmod is slightly better (0.68 compared to 1.1). The study results reveal weaknesses in both models, in terms of variability, absolute levels and limited spatial resolution. Simulation of the transition zone between the coasts and the open sea is still a demanding task for operational modelling. Thus, FerryBox data, combined with other observations with differing temporal and spatial scales, can serve as an invaluable tool not only for model evaluation, but also for model optimization by assimilation of such high-frequency observations.

scholarly journals The accuracy of alternative GDP growth forecasts: Do they represent a credible alternative to the official ones?

2015 ◽  
Vol 15 (3) ◽  
pp. 291-304
Author(s):  
Jiří Šindelář
Keyword(s):  
Trade Unions ◽  
Time Frame ◽  
Gdp Growth ◽  
Gradual Improvement ◽  
Error Measures ◽  
National Bank ◽  
Ministry Of Finance ◽  
Governmental Institutions ◽  
High Level ◽  
Growth Forecasts

Abstract The paper deals with the accuracy of the real GDP growth forecasts produced by two Czech non-governmental institutions: the Czech-Moravian Confederation of Trade Unions (CMKOS) and the Czech Banking Association (CBA) in the years 2007-2014 and 2011-2014 respectively. Utilizing a research method composed of simple (AFE), scale-dependent (RMSE) as well as relative (MASE) error measures, we found out that (i) CMKOS predictions achieved a lower forecasting error on average, beginning with a notable overestimation in the first turnover point from growth to decline (2008-2009), yet followed by gradual improvement resulting in superior accuracy over set benchmarks (Ministry of Finance, Czech National Bank, OECD) in later years (2010-2014). The CBA predictions, on the other hand, exhibited (ii) a high level of interconnection with official bodies (MF, CNB), but with overall inferior forecasting accuracy, despite the shorter time frame (2011-2014). Overall, the study suggests that of the two surveyed non-governmental bodies, only CMKOS forecasts represent a viable alternative to the official predictions published by the Ministry of Finance or the Czech National Bank, as CBA forecasts were found to be a less accurate satellite of these bodies.

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