[SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- From: "Ing. Giancarlo Guida" <gianguida@xxxxxxxx>
- To: Mark.Randol@xxxxxxxxxx
- Date: Sun, 02 Apr 2006 16:59:19 -0100
Hi folks,
I'd like to add my two cents to this interesting discussion.
From my point of view the most important quality of a model ( and
therefore simulation)
it is not its accuracy...
but its simplicity.
A smart engineer is able to create a simple model to have a look at
complex reality
because he knows which variable count more than other
what effects are more important than the details
and will understand from simple model how to manage the reality.
A "bad" engineer will be afraid of everything and will not be able to
eliminate
unnecessary details form his model
he will always look for super fast machine and super accurate simulator
just because he is not sure what really counts in the reality he is studying
and is better to wait a couple of days of calculation time that think
about his design...:-)))))
A good model will never be simple enough
Giancarlo
Mark Randol ha scritto:
> Time to test my new Out of the Office Reply filter...
>
> My fave is rather old. =20
> "The reason circuits don't work as designed is paper doesn't conduct
> electricity." - unknown? =20
>
> Maybe now it should be monitor faces instead of paper.
>
> The problem is that simulator vendors and professional modeling folks
> (again, not the ones that make million$) tout the accuracy of their
> methods and inexperienced (sometimes even ones that know better)
> engineers and management get the idea that everything is golden. I'm
> sure the folks know better, and don't 'intend' to leave that impression,
> but it's left there sitting on the table anyway, mingled among the full
> color brochures.
>
> Even the real systems are 'wrong'. Otherwise why would each one be a
> little different even with 'identical' setups. Even measurements have a
> degree if 'wrongness', even when performed properly.
>
> Skepticism of initial results is one of an engineer's most important
> tools.=20
>
> --
> Mark Randol, RF Evaluation & Application Engineer
> ON Semiconductor
> 901 S. Mopac Expressway
> Barton Oaks IV, Suite 343
> Austin, TX 78746
> 512-329-5640 (voice), 512-329-8151 (FAX)
> =20
>
>
>> -----Original Message-----
>> From: si-list-bounce@xxxxxxxxxxxxx=20
>> [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Faraydon Pakbaz
>> Sent: Friday, March 31, 2006 8:54 AM
>> To: art_porter@xxxxxxxxxxx
>> Cc: brett.grossman@xxxxxxxxx; si-list@xxxxxxxxxxxxx;=20
>> si-list-bounce@xxxxxxxxxxxxx
>> Subject: [SI-LIST] Re: Theory v. practice, following Re:=20
>> DesignCon quote
>> =20
>> The word accuracy is Fuzzy and Uncertain. There is no such=20
>> thing as a precise simulation or model but it cannot be=20
>> called inaccurate. Without out the color "white"
>> the color "black" is
>> meaningless. We rise and fall with simulation and models in=20
>> Engineering and Science. The model and simulation is a window=20
>> that we look at real system. Every Simulation and model is=20
>> accurate to certain degree. To call modeling and simulation=20
>> inaccurate is misleading.
>> =20
>> =20
>> Regards;
>> =20
>> Don Pakbaz
>> =20
>> Silicon Solutions Engineering
>> IBM Systems & Technology Group
>> =20
>> =20
>> =20
>> =20
>> =20
>> <art_porter@agile =20
>> =20
>> nt.com> =20
>> =20
>> =20
>> To=20
>> 03/31/2006 09:40 Faraydon =20
>> =20
>> AM =20
>> Pakbaz/Burlington/IBM@IBMUS, =20
>> =20
>> <brett.grossman@xxxxxxxxx> =20
>> =20
>> cc=20
>> =20
>> <si-list@xxxxxxxxxxxxx>, =20
>> =20
>> <si-list-bounce@xxxxxxxxxxxxx> =20
>> =20
>> Subject=20
>> RE: [SI-LIST] Re:=20
>> Theory v. =20
>> practice, following=20
>> Re: DesignCon =20
>> quote =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> Of course models and simulations are inaccurate. That's the=20
>> whole point. If they were 100.00000% accurate they would be=20
>> too complex to be useful and would take forever to run. I'm=20
>> reminded of the story of the man who was visiting a country=20
>> where the locals told him that at one time in the past they=20
>> had had a very detailed map that showed every mouse hole,=20
>> every blade of grass, very tree leaf, every speck of dust.=20
>> The problem was that when they unrolled the map it was bigger=20
>> than the country. And not only that, it was out of date=20
>> within a millisecond.
>> =20
>> Think about the abstractions we use all the time: R, L, and=20
>> C. There really are no such things as pure resistors,=20
>> capacitors, or inductors in the real world. There are=20
>> electromagnetic waves and fields (or at least we think there=20
>> are). But if you had to use Maxwell's equations with an=20
>> infinitely fine spatial mesh to solve every circuit, we'd=20
>> still be watching TV by candlelight.
>> =20
>> Art Porter
>> Agilent Technologies
>> =20
>> -----Original Message-----
>> From: si-list-bounce@xxxxxxxxxxxxx=20
>> [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Faraydon Pakbaz
>> Sent: Thursday, March 30, 2006 6:52 PM
>> To: brett.grossman@xxxxxxxxx
>> Cc: si-list@xxxxxxxxxxxxx; si-list-bounce@xxxxxxxxxxxxx
>> Subject: [SI-LIST] Re: Theory v. practice, following Re:=20
>> DesignCon quote
>> =20
>> OK OK...Hold on a second happy quoters ....We are all exited=20
>> and impressed over something that is not a true or false=20
>> statement but it is a paradox....
>> =20
>> Statements like:
>> =20
>> "All simulations are wrong but some simulations are useful"
>> =20
>> or
>> =20
>> "All models are wrong but some models are useful"
>> =20
>> make no sense consider the following:
>> =20
>> Epimenides was a Cretan who made one immortal statement:=20
>> "All Cretans are liars."
>> =20
>> Did he told the truth or lied?
>> =20
>> The answer is neither. Think about it.
>> =20
>> When someone makes a statement about simulation and model=20
>> like that, it means he/she is a very frustrated person( it=20
>> happens all the time in signal integrity analysis).
>> If I want to have a perfect
>> model or perfect simulation, I need to model or include every=20
>> variable in my simulation or model.
>> So if I want to spend the time to do that, I might as well=20
>> built the system or design etc. I will save lot of time to=20
>> market and I will be a hero. Read "Kurt Godel"
>> incompleteness theorem. No axiomatic
>> system can be perfect because it will be self reflecting and=20
>> will create paradox. Bertrand Russell and Alfred North=20
>> Whitehead made such a false claim in their "Principia=20
>> Mathematica" and Godel put the end to it. The art of matter=20
>> is how to use 7 variables instead of 100 variables to get an=20
>> insight into the design or system by simulation. Take=20
>> simulation and modeling seriously. Very very seriously.
>> =20
>> Regards;
>> =20
>> Don Pakbaz
>> =20
>> Silicon Solutions Engineering
>> IBM Systems & Technology Group
>> =20
>> =20
>> =20
>> =20
>> "Grossman, Brett"
>> <brett.grossman@i
>> ntel.com> =20
>> To
>> Sent by: <si-list@xxxxxxxxxxxxx>
>> si-list-bounce@fr =20
>> cc
>> eelists.org
>> =20
>> Subject
>> [SI-LIST] Re: Theory=20
>> v. practice,
>> 03/30/2006 07:32 following Re: DesignCon quote
>> PM
>> =20
>> =20
>> Please respond to
>> brett.grossman
>> =20
>> =20
>> =20
>> =20
>> =20
>> =20
>> Amen, to see the quotes (I am a collector).
>> =20
>> One of my favorites ( I would attribute to Scott McMorrow on=20
>> this list just because it was the first place I saw it).
>> =20
>> Relating to the success of some who are perhaps not the most=20
>> deserving.
>> "Even a blind squirrel finds a nut sometimes"
>> =20
>> =20
>> -----Original Message-----
>> From: si-list-bounce@xxxxxxxxxxxxx=20
>> [mailto:si-list-bounce@xxxxxxxxxxxxx]
>> On Behalf Of Richard Feldman
>> Sent: Thursday, March 30, 2006 1:42 PM
>> To: si-list@xxxxxxxxxxxxx
>> Cc: schumach@xxxxxx
>> Subject: [SI-LIST] Theory v. practice, following Re: DesignCon quote
>> =20
>> It's rare and refreshing to see an online quotation with its=20
>> attribution retained or restored!
>> Wikiquote (thanks to hint from Pat Zabinski) just helped me=20
>> to link an author to this old favorite:
>> =20
>> "In theory, there is no difference between theory and=20
>> practice.=3D3D20 But, in practice, there is."
>> =20
>> From Wikiquote
>> Jan L. A. van de Snepscheut (1953-1994), computer scientist=20
>> and educator This has also been attributed to Yogi Berra.
>> =20
>> -Rich
>> =20
>>
>>> -----Original Message-----
>>> From: si-list-bounce@xxxxxxxxxxxxx On Behalf Of Richard Schumacher
>>> Sent: Thursday, March 30, 2006 12:56 PM
>>> To: si-list@xxxxxxxxxxxxx
>>> Subject: [SI-LIST] Re: DesignCon quote =3D3D20 Here's a=20
>>>
>> reference to an=20
>>
>>> even older citation, which I can't now check:
>>> ..."[George] Box used it as a heading in a book chapter in=20
>>>
>> 1979.=3D3D20=20
>>
>>> =3D3D20 -----Original Message-----
>>> From: si-list-bounce@xxxxxxxxxxxxx On Behalf Of Zabinski, Patrick J.
>>> Sent: Thursday, March 30, 2006 2:36 PM
>>> To: si-list@xxxxxxxxxxxxx
>>> Subject: [SI-LIST] Re: DesignCon quote =3D3D20 I found a slightly=20
>>> different citation on WikiQuote, which suggests =3D
>>>
>> =3D3D3D
>>
>>> George Box and Norman Draper had two phrasings ...
>>> Wherever it came from, I like it...
>>> =3D3D20
>>> Pat
>>>
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Other related posts:
- » [SI-LIST] Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
- » [SI-LIST] Re: Theory v. practice, following Re: DesignCon quote
