Re: [N3-tech] simulator results

Hi All, Since we had some problems to schedule the meeting today, I will write down some comments I had on the results you obtained from the first version on the simulator. The we can discuss further in the next meeting... in the meantime you can prepare questions for me too ;-) First of all I would like to know if the result of the 10 different receivers is averaged at the end. I think so, right? Then, can you summarize here the formulas (or algorithms) you used on the simulations? You are only simulating the Brownian motion here and not the collisions between molecules... right? I can notice a delay in the concentration peak from Rx placed at 1000nm on... this is in fact a confirmation that there is a delay in the propagation and this is not possible to result from the solution of Fick's laws but only either from a simulation of the Brownian motion (nano-simulation) or from the solution of the Telegraph's equation from the relativistic diffusion theory. Actually the Telegraph equation should approach this behavior but at the same time I'm not expecting that it will model perfectly this delay behavior... as always in physics... the math is only an approximation of the real behavior, and the relativistic theory is a "first approximation" of the delay in the diffusion process... I see there are many fluctuation in the signal and this partly explains what I'm studying right now: the particle counting noise, which is caused by the fluctuation in the number of particles going back and forth in and out from the volume of the receiver... how big is the volume you're using to count the molecules? This is an important parameter... I assume it is spherical with a given radius. Well, according to the analysis I did, the power of the particle counting noise should have inverse proportionality with respect to this radius... is could be extremely interesting to test this behavior. I've also analyzed how to cut down the power of the particle counting noise without having a big received: it looks like the diffusion process has a sort of correlation time, beyond which we can consider two concentration measures as independent. If this correlation time, which happens to be equal to the radius of the receiver volume squared and divided by the diffusion coefficient, is enough lower than the inverse of the bandwidth of the system, then we can do multiple measures of the same concentration value (and consider the concentration quasi-constant) and have a mean value estimator of the concentration which is less noisy. the "negative" peak at approx 1750nm is quite interesting... we should investigate more on why this is happening... I'll think about it too... The channel transfer function shows a low-pass behavior with some fluctuations on the top. Are these fluctuations spaced in some regular way? Like following certain harmonics or a fixed law in frequency? Is the first graph you show the impulse response at 1micron? How many receivers are there in this computations? 1 or 10 like before? When you shift the FFT could you also shift the frequency values having the zero in the middle of the graph? So far these are my comments, but I think we can discuss further about these interesting results and brainstorm a bit on how to proceed. Thanks a lot and sorry for the delay... many things are going on at the same time for all of us and I wanted to make this comments without time pressure ;-) Please, let me know your answers to my comments, as well as any remarks you have on my explanations. Max -----Original Message----- From: n3-tech-bounces(a)n3cat.upc.edu [mailto:n3-tech-bounces@n3cat.upc.edu] On Behalf Of garralda(a)ac.upc.edu Sent: Tuesday, March 23, 2010 3:46 PM To: n3-tech(a)n3cat.upc.edu Subject: [N3-tech] simulator results hello everybody, these are some results obtained using the first version of the simulator. The pdf contains the graphics we told you (Massimiliano). if anyone has some data about realistic values for the amount of transmitted molecules (transmitted power) or any other comment i would appreciate it. Regards Nora