Fuzzy logic

====================== Yes, the hype is thick and fuzzy. :) I cannot defend fuzz logic, as I have never worked with it. But I know of s ome successful NN applications. Please allow me to give a long view with gross over-simplification. When sc ience erupted, (1700), the scientists went after the low hanging fruit. If physicists could not solve a problem, they passed it on to chemists who th en gave it to biologists. This originated the saying, "Difficult stuff roll s downhill." So today we have the accumulation of difficult problems which typically are multi-dimensional, vague (fuzzy), and contextual. This includ es problems like the cause of cancer, cause of senescence and death, variou s mechanisms of the human mind, collapse of civilizations, non-material bei ngs, etc. jb

I did a successful project with FL (energy reduction in a batch cycle device), and my all-singing all-dancing Zojirushi rice maker is allegedly neural-fuzzy.

Have not used FL directly for quite some time, there's usually another more conventional way to do things that's about as good, maybe better.

On a sunny day (Fri, 24 Jan 2014 16:12:38 -0500) it happened Spehro Pefhany wrote in :

I have written some neural net stuff many many years ago, there are nice libraries for Linux for that too. 'Fuzzy' has always been a hype, most of us have combined sort of digital and analog circuits or let's say circuits that were analog in some aspect and digital in some other aspect. I do not see the whole talking about it, few transistors schematic will do. Already in the sixties there was babble about 'fuzzy'. IIRC I did fuzzy with thyristors back then...

Maybe this is an other fuzzy?

is based upon human-like way of thinking and it is powerful tool for analysis of multidimensional data. Now, free web online calculator is available.

ogic.html

Just in case OP never answers: THe only notable change is that "fuzzy logic" is no longer (mis-)managements darling buzz phrase / sound bite / silver bullet.

That would be "quote-equals-quote-next-character", to me ;-)

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)

Whaddabout ".ne.".

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)

Would '\=' be better? (or '/='?)

Seems context is worth something. "Overloading", you know.

Too bad USENET never adopted escapes into Tex markup.

\neq

As in this:

Best regards, Spehro Pefhany

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=_NextPart_000_003E_01CF1A8B.BD2F1730 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

That's what HTML is for :^)

≤ =E2=89=A4 ≥ =E2=89=A5 ∝ =E2=88=9D Although =E2=88=9E is ∞, not \infty Ω =CE=A9 versus ω =CF=89 case sensitivity

I'm sure Berners-Lee had experience with TeX, writing papers or some = such.

Or, well... when were entities introduced? Were they HTML 1.0? Maybe = it was a later consortium thing in a later version.

Tim

I've always wondered why math support is so poor in HTML, especially because of where it came from. I wasn't aware of Mathjax. Thanks for the hint Spehro.

Jeroen Belleman

/= is C* for divide by.

\= is, I think, Prolog for not the same as. (*) and ceveral other languages that use C-like syntax

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No overloading?

such.

Another tool. I would have tried MathML first.

?-)

Hi, we have this subsea project where one of the challenges is to install a circuit board on the outside of a retrievable subsea installation (20" pipe), rated for 350 bar (5000 PSI) enviromental pressure, so the pressure load will be somewhat cyclic between 0 and 350 bar.

Some other equipment installed on this pipe is embedded in a hard, polyurethane (PUR) potting. So I am thinking to also embed the circuit board into this PUR potting. Since the surrounding potting material is quite hard, ShA 80, and that it is significant differences in the compressibility or bulk modulus of the PCB laminate (FR4) and the potting material, we are concerned that the compression differences between the PCB and the potting material will lead to high stress levels on the components mounted on the PCB. The components on the PCB is a few D2Packs and some 0603 resistors. The size of the PCB is 50x50 mm.

Two obvious alternatives is to put the PCB inside a 1-atm container. or submerge the PCB in some pressure compensated oil container. The reason not to choose one of these is to keep the size and complexity low.

So I am now thinking that this circuit board should first be potted in a form of softer potting material before it is embedded in the harder PUR potting surrounding the 20" pipe. So now I am wondering where to find, or what kind of soft potting material to chose for this purpose? And if this is really the best route to choose? Anny thoughts / experiences / suggestions, anyone?

Thanks..

Br, Rune

Misplaced message. I will repost in a new tread. Sorry about that.

Hi, we have this subsea project where one of the challenges is to install a circuit board on the outside of a retrievable subsea installation (20" pipe), rated for 350 bar (5000 PSI) enviromental pressure, so the pressure load will be somewhat cyclic between 0 and 350 bar.

Some other equipment installed on this pipe is embedded in a hard, polyurethane (PUR) potting. So I am thinking to also embed the circuit board into this PUR potting. Since the surrounding potting material is quite hard, ShA 80, and that it is significant differences in the compressibility or bulk modulus of the PCB laminate (FR4) and the potting material, we are concerned that the compression differences between the PCB and the potting material will lead to high stress levels on the components mounted on the PCB. The components on the PCB is a few D2Packs and some 0603 resistors. The size of the PCB is 50x50 mm.

Two obvious alternatives is to put the PCB inside a 1-atm container. or submerge the PCB in some pressure compensated oil container. The reason not to choose one of these is to keep the size and complexity low.

So I am now thinking that this circuit board should first be potted in a form of softer potting material before it is embedded in the harder PUR potting surrounding the 20" pipe. So now I am wondering where to find, or what kind of soft potting material to chose for this purpose? And if this is really the best route to choose? Anny thoughts / experiences / suggestions, anyone?

Thanks..

Br, Rune

Am 28.01.2014 11:18, schrieb Rune:

FR4 will swell in mineral oil and crack the vias. Kapton required. (BTW Kapton prepregs have a short shelf live. One needs a trustable manufacturer.)

No idea abt. potting. I have currently the opposite problem, i.e. outgassing.

regards, Gerhard

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There's no reason I can think of why I wouldn't go with a 1 
atmosphere pressure vessel.

For many years we had a product encapsulated by a professional encapsulating firm in very hard filled epoxy and they protected the pcb (which included diodes with glass-metal seals) by first dip and brush coating in a softer semi-flexible potting resin.

Now I look up the shore hardness of that softer resin and see it quoted at D45 which I reckon is not far off A80 so I think you may find your PUR resin at A80 will be alright with any compatible barrier that is just a bit softer.

Mind you our product never went to depth! HTH