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Feedback variable

A = Input Element. b = Feedback Variable. d = Disturbance or Load Variable. Gh = Feedback Sensor Transfer Function. Gp = Process Transfer Function. ... [Pg.200]

The feedback variables go with first order time delays r i towards their final values flioo- The variables of the subthreshold oscillations activate much slower than those for episode generation. In both subsystems, the positive feedback is faster than the negative feedback ... [Pg.203]

While the above simulations describe how the disease pattern vary as a function of the disease state, the following simulations show that our model can also account for kindling phenomena and autonomous progression. This needs some model extensions which were made in reference to the above-mentioned assumption of episode sensitization which are assumed to be due to residues (memory traces) of previous disease episodes. For simplicity, and because the real mechanisms are unknown, we introduced an additional, positive feedback loop which is implemented exactly in the same way as the other feedback variables [4—7, 25]. The model now also includes a dynamic disease variable Sp (Fig. 7.4a). The specialities are that it only activates when a disease episode occurs (episode sensitization) and that it has long relaxation times (memory trace). [Pg.205]

S-NDR Systems The Electrode Potential as Negative Feedback Variable. 142... [Pg.89]

In most electrochemical systems displaying nonlinear phenomena, the electrode potential is an essential variable, that is, it participates in one of the above-mentioned feedback loops.1 In the overwhelming number of cases it takes on the role of the activator variable, but occasionally it also acts as the negative feedback variable. Depending on the mechanistic role of the electrode potential, the instabilities that prevail the dynamic properties in these two classes of systems are fundamentally different. [Pg.92]

The existence of bistability in the //under conditions under which chemical variable, on which the current depends, exhibits bistability as a function of DL. Thus, in S-NDR systems we have to require that the dynamic equations contain a chemical autocatalysis. As set forth below, m takes the role of the negative feedback variable. The positive feedback might be due to chemical autocatalytic reaction steps as is the case in Zn deposition [157, 158] or CO bulk oxidation on Pt [159], S-shaped current-potential characteristics may also arise in systems with potential-dependent surface phase transitions between a disordered (dilute) and an ordered (condensed) adsorption state due to attractive interactions among the adsorbed molecules. [Pg.143]

Concepts developed in nonlinear dynamics facilitated the classification of nonlinear phenomena in electrochemical systems and revealed the origins of the diversity of temporal and spatial patterns in electrochemical systems. The diversity results on the one hand from the fact that the electrode potential might act as a positive or as a negative feedback variable. On the other hand, it is a consequence of the different kinds of spatial coupling present in an electrochemical cell and of the unique property that the extent of the spatial couplings is influenced by parameters that can be easily manipulated in an experiment. [Pg.198]

In this chapter, the experimentally observed wave forms are not reviewed from the point of view of dynamic systems theory. Rather, we focus on the physical mechanisms that cause complex oscillatory behavior. In general, the phenomena considered require the presence of autocatalysis and two negative feedback loops. Recall that simple oscillations are caused by the interaction of an autocatalytic variable and one negative feedback variable. Thus it is plausible to look for an additional variable that introduces a second negative feedback loop into the two mechanisms considered in the last section. [Pg.53]

The first goal in our methodology is to transform an algorithm given in nested-loop form, which may include non-constant dependencies, to an equivalent URE with localized parametric DVs. The motivation for this starting point is also discussed in chapter 4. The applicability of such a transformation is restricted by the complexity of the index functions of the feedback variables. Therefore, our attention is focused on WSACs [20], which are characterized by identical linear index functions of the feedback variable. In this approach UREs are derived directly, in contrast to the technique described in chapter 4 where the dependence graph (DG) is extracted. [Pg.98]

A variable that appears in both sides of a statement is called a feedback variable. Any element of the set A (F(i)) i G / is called a variable instance. Variables with common name but diiferent index functions are considered as... [Pg.98]

According to the above conditions, broadcasting occurs when a variable appears in the right-hand side of the statement only. Fan-in is associated with feedback variables and exists when the statement can be written in the following form ... [Pg.100]

We recall that, for a sufficiently long relaxation time T, the feedback variable y provides a delayed feedback that causes the system, which is bistable for appropriate values of A. and /ir as a result of the cubic terms in the rate equation for x, to become oscillatory. [Pg.223]

Transition tables for asynchronous circuits can convey significant information more quickly by placing circles about the next states that are stable, unstable next states are uncircled. The output and feedback variables have been labeled Q to identify them as state variables. This identifies the transition table for the asynchronous circuit with the transition table of the synchronous circuit. There is usually at least one next state entry that is, the same as the current state in each row. If this were not true then that state would not be stable. The procedure for obtaining a transition table is summarized in Table 1.28. [Pg.82]

The portion of the control element which determines the difference between the set point and the measured feedback variable. [Pg.254]

In measurement, the difference between the value found and the true value in control, the set point minus the measured value of the feedback variable. [Pg.255]

The portion of the control loop which estabhshes the primary feedback variable in terms of the controlled variable. [Pg.255]

The void feedback variable comes from flie coolant and its potential to undergo phase changes inside the core. One example of a negative feedback coefficient can be found in a BWR that uses water as the moderator. If the power level increases inside... [Pg.58]


See other pages where Feedback variable is mentioned: [Pg.224]    [Pg.95]    [Pg.111]    [Pg.151]    [Pg.54]    [Pg.637]    [Pg.100]    [Pg.490]   
See also in sourсe #XX -- [ Pg.98 ]




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