scholarly journals UN Stabilisation Operations and the Problem of Non-Linear Change: A Relational Approach to Intervening in Governance Ecosystems

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Adam C. Day ◽  
Charles T. Hunt
Keyword(s):  
Linear Change ◽  
Relational Approach ◽  
Non Linear

The Maximum Transient Resonance Response of Rotating Blades With Regard to Centrifugal Force and Non-Linear Damping Effects

1997 ◽  
Author(s):  
Horst D. Irretier
Keyword(s):  
Centrifugal Force ◽  
Natural Frequencies ◽  
Linear Change ◽  
Rotating Blades ◽  
Operation Process ◽  
Non Linear ◽  
Linear Damping ◽  
Pass Through ◽  
Run Up ◽  
Approximate Formulas

During the operation process in many types of fluid flow machines the rotating blades pass through various resonances e.g. during run-up or run-down or other transient conditions. Therefore, for the high cycle fatigue problem of the blades it might be important to consider the transient vibratory response of the blades during these passages through resonance and to get knowledge about the occuring maximum vibratory stresses. In the paper, approximate formulas are presented which allow the estimation of the maximum transient response of the blades. Thereby, the influence of the change of the natural frequencies due to the increasing or decreasing centrifugal force field during the run-up or run-down, respectively, is taken into consideration. Basically, the approximate formulas are based on a linear change of the natural frequencies versus time and on a linear viscous type of damping. Extensions to account for parabolic changes which are more realistic for centrifugal effects and for non-linear damping models e.g. friction damping or turbulence damping are discussed.

scholarly journals Application of the Gaussian anamorphosis to assimilation in a 3-D coupled physical-ecosystem model of the North Atlantic with the EnKF: a twin experiment

2009 ◽  
Vol 6 (1) ◽  
pp. 617-652 ◽  
Author(s):  
E. Simon ◽  
L. Bertino
Keyword(s):  
North Atlantic ◽  
Coupled Model ◽  
Surface Concentration ◽  
Ecosystem Model ◽  
Concentration Data ◽  
Linear Change ◽  
The North ◽  
Change Of Variables ◽  
Non Linear ◽  
Non Gaussian

Abstract. We consider the application of the Ensemble Kalman Filter (EnKF) to a coupled ocean ecosystem model (HYCOM-NORWECOM). Such models, especially the ecosystem models, are characterized by strongly non-linear interactions active in ocean blooms and present important limitations for the use of data assimilation methods based on linear statistical analysis. Besides the non-linearity of the model, one is confronted with physical/biological limitations, the analysis state having to be consistent with the model, especially with the constraints of positiveness of some variables. Furthermore the non-Gaussian distributions of the biogeochemical variables break an important assumption of the linear analysis, leading to a loss of optimality of the filter. We present an extension of the EnKF dealing with these limitations by introducing a non-linear change of variables (anamorphosis function) in order to execute the analysis step in a Gaussian space. We present also the initial results of the application of this non-Gaussian extension of the EnKF to the assimilation of simulated chlorophyll surface concentration data in a North Atlantic configuration of the HYCOM NORWECOM coupled model.

Resilience and Non-Linear Change in Island Tourism

2013 ◽  
Vol 15 (1) ◽  
pp. 43-67 ◽  
Author(s):  
Amran Hamzah ◽  
Mark P. Hampton
Keyword(s):  
Linear Change ◽  
Non Linear

[P3-345]: BETA-AMYLOID BURDEN PREDICTS NON-LINEAR CHANGE IN BOLD MODULATION TO COGNITIVE CHALLENGE IN HEALTHY AGING

2017 ◽  
Vol 13 (7S_Part_22) ◽  
pp. P1086-P1087
Author(s):  
Chris M. Foster ◽  
Kristen M. Kennedy ◽  
Marci M. Horn ◽  
David A. Hoagey ◽  
Karen M. Rodrigue
Keyword(s):  
Healthy Aging ◽  
Beta Amyloid ◽  
Amyloid Burden ◽  
Linear Change ◽  
Non Linear ◽  
Cognitive Challenge

scholarly journals Application of the Gaussian anamorphosis to assimilation in a 3-D coupled physical-ecosystem model of the North Atlantic with the EnKF: a twin experiment

Ocean Science ◽  
2009 ◽  
Vol 5 (4) ◽  
pp. 495-510 ◽  
Author(s):  
E. Simon ◽  
L. Bertino
Keyword(s):  
North Atlantic ◽  
Coupled Model ◽  
Surface Concentration ◽  
Ecosystem Model ◽  
Concentration Data ◽  
Linear Change ◽  
The North ◽  
Change Of Variables ◽  
Non Linear ◽  
Non Gaussian

Abstract. We consider the application of the Ensemble Kalman Filter (EnKF) to a coupled ocean ecosystem model (HYCOM-NORWECOM). Such models, especially the ecosystem models, are characterized by strongly non-linear interactions active in ocean blooms and present important difficulties for the use of data assimilation methods based on linear statistical analysis. Besides the non-linearity of the model, one is confronted with the model constraints, the analysis state having to be consistent with the model, especially with respect to the constraints that some of the variables have to be positive. Furthermore the non-Gaussian distributions of the biogeochemical variables break an important assumption of the linear analysis, leading to a loss of optimality of the filter. We present an extension of the EnKF dealing with these difficulties by introducing a non-linear change of variables (anamorphosis function) in order to execute the analysis step in a Gaussian space, namely a space where the distributions of the transformed variables are Gaussian. We present also the initial results of the application of this non-Gaussian extension of the EnKF to the assimilation of simulated chlorophyll surface concentration data in a North Atlantic configuration of the HYCOM-NORWECOM coupled model.

[IC-P-117]: BETA-AMYLOID BURDEN PREDICTS NON-LINEAR CHANGE IN BOLD MODULATION TO COGNITIVE CHALLENGE IN HEALTHY AGING

2017 ◽  
Vol 13 (7S_Part_2) ◽  
pp. P91-P91
Author(s):  
Chris M. Foster ◽  
Kristen M. Kennedy ◽  
Marci M. Horn ◽  
David A. Hoagey ◽  
Karen M. Rodrigue
Keyword(s):  
Healthy Aging ◽  
Beta Amyloid ◽  
Amyloid Burden ◽  
Linear Change ◽  
Non Linear ◽  
Cognitive Challenge
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