Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 33 for “"Nonstationarity"”.
-
Exploring spatial heterogeneity of CPUE year trend and nonstationarity in fisheries stock assessment, an example based on Atlantic Weakfish (Cynoscion regalis)
Quantitative population dynamics modeling is needed to evaluate the stock status and fisheries management plans to provide robust model and management strategies. Atlantic Weakfish (Cynoscion regalis), one important commercial and recreational fish species along the west coast of Atlantic Ocean …
-
Hydrological Frequency Analysis under Nonstationary Conditions
… and other changes in the watersheds may induce nonstationarity in hydrometeorological variables. Under nonstationary scenarios, the nonstationary HFA (NS-HFA) is the theoretical choice. To implement the NS-HFA with more confidence, further understanding of the impacts of nonstationarity on the …
-
Assessing the Robustness of Deep Learning Streamflow Models Under Climate Change
… the robustness of these models under climate nonstationarity by creating train and test data splits thatare designed to simulate climate bias. By training on forcing data from hydrological years of high (low) aridity and testing on data from hydrological years of low (high) aridity, we can …
-
Analysis of long-term precipitation sequencing patterns in North America
… events, is an important factor in describing nonstationarity in climate variability. It is a vital, yet often overlooked part of developing long-term climate predictions. Precipitation sequencing, which is based on rainfall of all magnitudes, is not well understood in part because much of …
-
Finding theoretical and empirical solutions to the three major puzzles of exchange rate economics : applications in respect of Southern African macroeconomic data
… uses Bayesian unit root testing and nonlinear nonstationarity tests associated with the smooth transition autoregressive family of models. According to Bayesian unit root test results, the nonstationarity hypothesis received small posterior probability relative to other hypotheses. In this …
-
Multivariate hydrological frequency analysis and risk mapping
… independence transformation approach etc.; (2) nonstationarity was found more or less existed in the rainfall and streamflow time series, but according to the nonstationary test, in most cases, the stationarity assumption may be approximately valid; (3) the multivariate frequency analysis …
-
Spatial dynamics modeling for data-poor species using examples of longline seabird bycatch and endangered white abalone
… weighted approach to explore spatial nonstationarity in seabird bycatch, i.e., spatial variation in the parameters that describe relationships between biological processes and environmental factors. Estimates of parameters exhibited high spatial variation. With the white abalone …
-
Transport of solutes in complex hydrogeological media
… structures displayed a trend, suggesting nonstationarity of the concentration field and the spatial continuity was higher in the transverse directions than the longitudinal direction.
-
Improving Seismic-to-well Ties
… time warping and addressing slowly time-variant nonstationarity in a sliding Gaussian window.
-
State-dependent model, multi-step-ahead, multiple forecasts: Experience with the United States unemployment rate series
… extended to account for both nonlinearity and nonstationarity. Also, some of the existing tests for linearity in the time domain have been applied and indicate the existence of bilinear type nonlinearity in the series. Models fitted in the state dependent framework and the bilinear models have …
-
Estimating uncertainty models for speech source localization in real-world environments
… problem in this way, we take advantage of the nonstationarity of speech in a way that is similar to the psychoacoustics of the precedence effect. For source separation, we use the same weighting function as part of a simple probabilistic generative model of localization cues. We combine this …
-
Performance analysis of subaperture processing using a large aperture planar towed array
… limited spatial coherence of signals and nonstationarity of high bearing rate interference sources common in littoral regions of strategic importance. This thesis presents subarray processing as a method of improving passive detection performance using such large arrays. This thesis …
-
Stochastic analysis of dense nonaqueous phase liquid dissolution in naturally heterogeneous subsurface systems
… by a stochastic analysis, which includes nonstationarity in the concentration field to address both boundary and downstream effects. An extrapolation of the effective properties is performed for the large spatial variability of hydraulic and dissolution parameters. The extrapolation is …
-
On stationary and nonstationary fatigue load modeling using autoregressive moving average (ARMA) models
… used to determine the success of the modeling of nonstationarity. Justification of the method is obtained through comparison of rainflow cycle distributions and resulting fatigue lives of original and simulated loadings. Due to the relatively small number of Fourier coefficients needed together …
-
A STUDY OF UNIT ROOT TESTING
… we propose the use of graphical aids to detect nonstationarity as well as determine an appropriate model for the stochastic part of the series. To test for the presence of a unit root we recommend the testing strategy of Dickey, Bell and Miller. Three real time series were analyzed using the …
-
Statistical analysis of low level atmospheric turbulence
… the possible trend in the time series. The nonstationarity of the time series was determined by applying a non-parametric statistical test on the statistical quantities of each block in the time series. The smoothed spectral density estimates have been obtained by using cosine tapering data …
-
Data-based Mechanistic Modelling (DBM) of Nonlinear Environmental Systems.
… such time variable parameters may reflect either nonstationarity or nonlinearity; the latter arising if the variations are also shown to be state dependent. Statistical time series methods for estimating time varying parameters (TVP) and the use of these methods in state dependent parameter …
-
*Interactive Genetic Algorithms for Adaptive Decision Making in Groundwater Monitoring Design
… of various human factors, such as human fatigue, nonstationarity in preferences, and the cognitive learning process of the human decision maker, have also been addressed while constructing the proposed systems. The result of this research is a highly adaptive and enhanced interactive …
-
Development and Uncertainty Quantification of Hurricane Surge Response Functions and Sea-Level Rise Adjustments for Coastal Bays
… trends, such as rising sea levels, introduce nonstationarity into the simulated and historical surge datasets. A common approach to estimating total flood elevations is to take the sum of projected sea-level rise (SLR) and present day surge (static approach); however, this does not account for …
-
Analyzing the Effect of Moving Resonance on Seismic Response of Structures using Wavelet Transforms
… (frequency content) with time (spectral nonstationarity).The phenomenon of moving resonance which occurs when the frequency content of the ground motion shifts in a similar manner as the natural frequencies of the structural response, is likely a contributor to variability. This brings …
Page 1 of 2