Writing PDEs as differential equations on Hilbert space

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SUMMARY

The discussion focuses on the control of the 1-D heat equation represented as a differential equation on Hilbert space. The equation is expressed as \(\frac{\partial u(x,t)}{\partial t} = \frac{\partial^2 u(x,t)}{\partial x^2}\) with boundary conditions \(u(0,t)=0\) and \(u_x(1,t)=w(t)\), where \(w(t)\) is the control input. The authors reformulate the equation to \(v(t) = Av(t) + \delta_1(x)w(t)\), where \(A\) is the double differential operator and \(v(t) = u(\cdot,t)\) is the state in the \(L_2(0,1)\) space. The discussion seeks clarification on the equivalence of the two formulations.

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agahlawa
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Hi,

I was reading a paper on control of the 1-D heat equation with boundary control, the equation being
\frac{\partial u(x,t)}{\partial x}= \frac{\partial^2 u(x,t)}{\partial x^2} with boundary conditions:

u(0,t)=0 and u_x(1,t)=w(t), where w(t) is the control input.

The authors then proceed to write the equation as:

v(t)=Av(t)+\delta_1(x)w(t) where A is the double differential operator, v(t)=u(\cdot,t) is the state with L_2(0,1) being the state space and \delta_1 being the dirac delta distribution centered at x=1.

I understand the idea behind putting A but I do not understand how the two equations are same.

Any help is much appreciated.
Thanks.
 
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I will be following this thread. :smile:

agahlawa said:
Hi,

\frac{\partial u(x,t)}{\partial x}= \frac{\partial^2 u(x,t)}{\partial x^2}
Any help is much appreciated.
Thanks.

For a diffusion equation, the first derivative is wrt to time.
\frac{\partial u(x,t)}{\partial t}= \frac{\partial^2 u(x,t)}{\partial x^2}
 
agahlawa said:
Hi,

I was reading a paper on control of the 1-D heat equation with boundary control, the equation being
\frac{\partial u(x,t)}{\partial t}= \frac{\partial^2 u(x,t)}{\partial x^2} with boundary conditions:

u(0,t)=0 and u_x(1,t)=w(t), where w(t) is the control input.

The authors then proceed to write the equation as:

v(t)=Av(t)+\delta_1(x)w(t) where A is the double differential operator, v(t)=u(\cdot,t) is the state with L_2(0,1) being the state space and \delta_1 being the dirac delta distribution centered at x=1.

I understand the idea behind putting A but I do not understand how the two equations are same.

Any help is much appreciated.
Thanks.

Sorry, was a typo. Fixed. Thank you.
 

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