Re: New Standards for Freight Cars Models


Bruce Smith
 

On May 27, 2008, at 1:07 AM, Didrik A. Voss wrote:
Gentlemen,
There are women present in the hobby, and it certainly does nothing to improve their sense belonging if folks representing the NMRA continue to ignore or insult them...

Didrik Voss response:
The article was reviewed by two electronics engineers; one with a
Master Degree and one with a PhD. Both have over 20 years experience
working for major international electronics firms. What are your
credentials?
Other than having recently reached the pinacle of academic rank and therefor feeling obliged to pontificate on all subjects, whether I have knowledge of them or not <G>? My scientific credentials are public knowledge. My area of expertise is molecular medicine. However, before you go "Ah-Ha!" I have a working knowledge of electronics associated with electrophysiology and am frequently called upon to review grant proposals and papers that have electrical components to the work. I am not a DCC expert, nor do I pretend to be one, although I think I probably have a better than average ability to understand what goes on inside those "black boxes". When necessary, I consult my "better-half" who is a solid-state physicist, currently specializing in silicon carbide device synthesis.

However, my concerns with your article did not lie specifically with the electronics, and thus I am not surprised that the technical details were deemed "correct" by the experts. Rather, I was concerned that the basic hypothesis was flawed, a situation that does not require an electrical engineer to identify. I have donated that issue of Scale Rails to my daughter Brianna's school (she, BTW, is a model railroader with a "lifetime pass" to our listmeister's layout and decidedly not covered by your salutation) so if you would like more specific comments, please send me an electronic copy and I will be happy to re-read it, provide you with the reasoning that led to my concerns and discuss this with you further.

Didrik Voss response:
If you re-read the article, you will realize the one locomotive
failed due to a dummy plug with a capacitor that causes the DCC
command station to shut down. The other locomotive had a dummy plug
without the capacitor included. Both locomotives passed the other
three Standards (S-2, S-4, S-7).
Do you have any idea whether the difference in the dummy plugs is systematic or coincidental? There are a number of possible explanations on why two models from the same company might have different dummy plugs - which is correct in this instance? With an N of 1 for each locomotive model, I submit that you cannot tell me what the chance is of having a "failing plug" in the next model off the shelf, because, you did not look... As such, this is a text-book example of an unsupported conclusion based on insufficient sample size.

Regards
Bruce

Bruce F. Smith
Auburn, AL
http://www.vetmed.auburn.edu/index.pl/bruce_f._smith2

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