The search session has expired. Please query the service again.
Displaying 101 –
120 of
143
No other concepts have shaken so deeply the bases of engineering like those of positive
and negative feedback. They have played a most prominent role in engineering since the beginning
of the previous century. The birth certificate of positive feedback can be traced back to a pair of
patents by Edwin H. Armstrong in 1914 and 1922, whereas that of negative feedback is already
lost in time. We present in this paper a short review on the feedback's origins in the fields of
engineering and biology....
Biological systems are able to switch their neural systems into inhibitory states and it is therefore important to build mathematical models that can explain such phenomena. If we interpret such inhibitory modes as `positive' or `negative' steady states of neural networks, then we will need to find the corresponding fixed points. This paper shows positive fixed point theorems for a particular class of cellular neural networks whose neuron units are placed at the vertices of a regular polygon. The...
In this paper, sharp a priori estimate of the periodic solutions is obtained for the discrete analogue of the continuous time ratio-dependent predator-prey system, which is governed by nonautonomous difference equations, modelling the dynamics of the competing preys and one predator having nonoverlapping generations. Based on more precise a priori estimate and the continuation theorem of the coincidence degree, an easily verifiable sufficient criterion of the existence of positive periodic solutions...
An existence theorem is proved for the scalar convolution type integral equation .
We consider the number of trophic levels in a food chain given by the
equilibrium state for a simple mathematical model with ordinary differential
equations which govern the temporal variation of the energy reserve in each
trophic level. When a new trophic level invades over the top of the chain,
the chain could lengthen by one trophic level.
We can derive the condition that such lengthening could
occur, and prove that the possibly longest chain is globally stable.
In some specific cases,...
Currently displaying 101 –
120 of
143