Faculty Opinions recommendation of Maximum entropy and the state-variable approach to macroecology.

2008 ◽  
Author(s):  
Brian Maurer
Keyword(s):  
Maximum Entropy ◽  
The State ◽  
State Variable ◽  
Variable Approach

MAXIMUM ENTROPY AND THE STATE-VARIABLE APPROACH TO MACROECOLOGY

Ecology ◽  
2008 ◽  
Vol 89 (10) ◽  
pp. 2700-2711 ◽  
Author(s):  
J. Harte ◽  
T. Zillio ◽  
E. Conlisk ◽  
A. B. Smith
Keyword(s):  
Maximum Entropy ◽  
The State ◽  
State Variable ◽  
Variable Approach

Sensitivities by the state variable approach

SIMULATION ◽  
1967 ◽  
Vol 8 (6) ◽  
pp. 337-343 ◽  
Author(s):  
Thomas W. Kerlin
Keyword(s):  
Frequency Response ◽  
The State ◽  
Efficient Procedure ◽  
State Variable ◽  
Sensitivity Equations ◽  
Variable Approach ◽  
Computer Calculations ◽  
Simple Matrix ◽  
Large Systems ◽  
Digital Computers

The well-known procedures for calculating transient-re sponse sensitivities, frequency-response sensitivities, and pole sensitivities have been successfully and profitably applied for several years. However, the usual formulations are not well suited for analysis of large systems on modern analog or digital computers. Expressions for these sensitivi ties are developed in this paper using simple matrix ma nipulations (usually referred to as the state variable ap proach). The state variable formulation illustrates clearly the structure of the sensitivity equations and provides an efficient procedure for computer calculations.

Quantification of Numerical Stiffness for a Unified Viscoplastic Constitutive Model

1990 ◽  
Vol 112 (3) ◽  
pp. 271-276 ◽  
Author(s):  
S. M. Arnold
Keyword(s):  
Constitutive Model ◽  
State Space ◽  
Copper Alloy ◽  
Jacobian Matrix ◽  
The State ◽  
Maximum Difference ◽  
Material Parameters ◽  
State Variable ◽  
Variable Approach ◽  
State Point

Here the question of numerical stiffness pertaining to a unified viscoplastic constitutive model is examined. The viewpoint maintained throughout this study is the state variable approach. Stiffness is quantified by examining, analytically, the eigenvalues of the associated Jacobian matrix. Specific results, in the form of stiffness contours, for the material parameters characterizing the copper alloy NARloy-Z are presented in the associated uniaxial state space. The results indicate that the potential for numerical stiffness does exist, however the severity is highly dependent upon the location of the state point within the state space. Finally a qualitative analogy between the maximum difference in stiffness indicating eigenvalues and the G vectors of the corresponding state space is suggested.

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