Article View: sci.nonlinear
Article #43Re: Turtles All the Way Down
From: Harry Erwin
Date: Sat, 15 Oct 1994 15:19
Date: Sat, 15 Oct 1994 15:19
30 lines
2559 bytes
2559 bytes
My numerical integration prof just walked us through advective systems last night (a 3-hour lecture delivered in 2.5 hours--my mental digestive processes are still churning). He discussed the practical limitations on the various integration schemes: Central difference in space, forward euler in time: tends to have monotonicity problems. Stochastic resonance processes in neural systems would not do well with this scheme. First order upwind: conditionally stable, but diffusion occurs. Neurons are known to show hyperacuity in some contexts by detecting the tight synchronization of inputs. This scheme would have problems doing that. Lax-Wendroff: conditionally stable but non-monotonic. Again, problems in the context of stochastic resonance. Flux-corrected transport: fully conservative and preserves monotonicity. I would expect problems though with distributed synchronization of neurons. I'm beginning to get the impression that current PDE schemes can be expected to find the aspects of neuron dynamics that I'm interested in 'at the bleeding edge.' Godunov's theorem seems to imply that an accurate neural system model has to make use of non-linear schemes. -- Harry Erwin Internet: herwin@gmu.edu Just a dumb graduate student working on Katchalsky network models.... (And if you believe that, I have a ranch in California to sell you.)
Technical Details
Message-ID:
<37orud$5ln@portal.gmu.edu>Path:
arc1-ca.pugleaf.net!bga.com!news.sprintlink.net!pipex!uunet!hearst.acc.Virginia.EDU!portal.gmu.edu!vanish!herwinReferences:
<37kblp$ak1@universe.digex.net> <37kln5$nh3@portal.gmu.edu> <37l2d0$hpr@mp.cs.niu.edu> <Cxo7oo.I8w@murdoch.acc.Virginia.EDU>Show Full Headers
Complete Article Headers
X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fa00e,2046408eafcfd07 X-Google-Attributes: gidfa00e,public X-Google-Thread: 1045ed,fd68b54591b3153e X-Google-Attributes: gid1045ed,public X-Google-Thread: 10681a,fd68b54591b3153e X-Google-Attributes: gid10681a,public X-Google-Thread: 10ca9b,fd68b54591b3153e X-Google-Attributes: gid10ca9b,public X-Google-ArrivalTime: 1994-10-15 08:45:13 PST Path: arc1-ca.pugleaf.net!bga.com!news.sprintlink.net!pipex!uunet!hearst.acc.Virginia.EDU!portal.gmu.edu!vanish!herwin From: herwin@vanish (Harry Erwin) Newsgroups: sci.nonlinear,sci.cognitive,bionet.neuroscience,comp.ai.philosophy Subject: Re: Turtles All the Way Down Followup-To: sci.nonlinear,sci.cognitive,bionet.neuroscience,comp.ai.philosophy Date: 15 Oct 1994 15:19:41 GMT Organization: George Mason University Lines: 30 Message-ID: <37orud$5ln@portal.gmu.edu> References: <37kblp$ak1@universe.digex.net> <37kln5$nh3@portal.gmu.edu> <37l2d0$hpr@mp.cs.niu.edu> <Cxo7oo.I8w@murdoch.acc.Virginia.EDU> NNTP-Posting-Host: science.gmu.edu Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Newsreader: TIN [version 1.2 PL2]