Dynamic Systems Modeling of Cortisol Stress Response

2008 ◽  
Author(s):  
D. M. Tilbury ◽  
B. T. Felt ◽  
N. Kaciroti ◽  
L. Wang ◽  
T. Tardif
Keyword(s):  
Dynamic Systems ◽  
Stress Responses ◽  
Model Fitting ◽  
Stressful Events ◽  
Single Input Single Output ◽  
Single Output ◽  
Cortisol Responses ◽  
Single Input ◽  
Systems Models ◽  
Discrete Time Models

This paper presents preliminary results for using dynamic systems models to describe cortisol responses to stressful events. Linear, single-input single-output discrete-time models are used. Choices that must be made regarding interpolation and input modeling are discussed in some detail. Results are presented that indicate an impulse model for the stressful input gives a better fit than no input, and that logarithmic transformation of the data before model fitting gives no better results than using the raw data. The issue of stability of the resulting models is discussed. In addition, the paper discusses how the resulting dynamic systems models can be used for statistical analysis, as well as for predicting future stress responses.

scholarly journals Robust Observer for a Class of Nonlinear SISO Dynamical Systems

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
David Rosas ◽  
Joaquin Alvarez ◽  
Patricia Rosas ◽  
Raul Rascon
Keyword(s):  
Dynamic Systems ◽  
Sliding Mode ◽  
Observer Design ◽  
Parameter Uncertainties ◽  
Single Input Single Output ◽  
Single Output ◽  
Equivalent Control ◽  
Bounded Disturbances ◽  
Single Input ◽  
Second Order Sliding Mode

A procedure to design an asymptotically stable second-order sliding mode observer for a class of single input single output (SISO) nonlinear systems in normal form is presented. The observer converges to the system state in spite of the existence of bounded disturbances and parameter uncertainties affecting the system dynamics. At the same time, the observer estimates the disturbances without the use of an additional filter to recover the equivalent control. The observer design is modular; each module of the observer is applied to each equation of state of the plant. Because of this, the proposed observer can be applied to a broader class of dynamic systems. The performance of the observer is illustrated in numerical and experimental form.

Comparative analysis of SISO and wavelength diversity-based FSO systems at different transmitter power levels

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Varun Srivastava ◽  
Abhilash Mandloi ◽  
Dhiraj Kumar Patel
Keyword(s):  
Optical Signal ◽  
Free Space Optical ◽  
Optical Source ◽  
Transmit Power ◽  
Single Input Single Output ◽  
Transmitter Power ◽  
Single Output ◽  
Communication Links ◽  
Single Input ◽  
Matching Performance

AbstractFree space optical (FSO) communication refers to a line of sight technology, which comprises optical source and detector to create a link without the use of physical connections. Similar to other wireless communication links, these are severely affected by losses that emerged due to atmospheric turbulence and lead to deteriorated intensity of the optical signal at the receiver. This impairment can be compensated easily by enhancing the transmitter power. However, increasing the transmitter power has some limitations as per radiation regulations. The requirement of high transmit power can be reduced by employing diversity methods. This paper presents, a wavelength-based diversity method with equal gain combining receiver, an effective technique to provide matching performance to single input single output at a comparatively low transmit power.

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