NIST blew WTC7 Stage 1 analysis

Dragon37 said:
So let me get this right. Your claim...
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To whom are you referring ?

is that the building was collapsing BEFORE the proposed NIST time?
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Read the thread title and OP.

I see you don't pay much heed to those sorts of things either so you don't even consider that both motion and lens distortion could be giving your data false positives.
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Early motion is under a pixel in magnitude. Lens distortion is negligible. Camera motion is extracted via subtraction of static region data.
 
uglypig said:
[qimg]http://femr2.ucoz.com/_ph/7/2/666377698.jpg[/qimg]

[qimg]http://i711.photobucket.com/albums/ww114/peterene/fig_5_20.jpg[/qimg]

Only two pics, folks. Some very large local collapse followed by 2 minutes of global deformation. That's why NIST's model doesn't reach freefall. The global collapse took two whole minutes. So it doesn't surprise me that it entered freefall.
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I'm not going to look at all of the video analysis, although it looks very interesting. So given you are 100% correct, then I would applaud your efforts. Seems like you just confirmed that the collapse was due to gradual structural failure and not a sudden impulse such as controlled demolition would induce. Good job!
 
femr2 said:
To whom are you referring ?
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It doesn't matter


Read the thread title and OP.
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I did and I read your posts and everyone elses and you are saying that the NIST stage 1 is in error when you both pretty much confirm the same thing. There was motion and the building collapsed from a progressive event and nothing more.


Early motion is under a pixel in magnitude. Lens distortion is negligible. Camera motion is extracted via subtraction of static region data.
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Right, right a single pixel out of reference with it's surroundings and for a short period of time. So what? Again your failure to take the long view has resulted in you confirming a progressive collapse and not a sudden event. You have "confirmed" the event is much longer than most toothers claim. You claim the inside was essentially removed before the exterior structure fell. You confirm it was twisting and distorting as it did so. And with claiming all of this and that the movement/distortion was lateral you have set a up a perfect reason why there was a short spell of freefall.

Congratulations you have successfully debunked not only yourself but the rest of the truthers that have moved from their failing to prove an inside job with the WTC 1 and 2 to WTC 7 9/11's Grassy Knoll. Guess what you just proved there was no one on that 9/11 grassy knoll.
 
of course you also seem to have no supporting evidence that this motion is exclusive to CD.
 
Dragon37 said:
It doesn't matter
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It does when you are making bizarre and erronious suggestion of "claims" I have not made :rolleyes:

you are saying that the NIST stage 1 is in error
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Correct.

Right, right a single pixel out of reference with it's surroundings and for a short period of time.
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What ?

Again your failure to take the long view
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LOL. What are you talking about ? I think perhaps you are confused about who you are conversing with.

You have "confirmed" the event is much longer than most toothers claim.
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Correct.

You claim the inside was essentially removed before the exterior structure fell.
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No I don't.

You confirm it was twisting and distorting as it did so.
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Confirm ? Hmm. NIST didn't look at early motion data.

And with claiming all of this and that the movement/distortion was lateral
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You are getting yourself all twisted/distorted.

you have set a up a perfect reason why there was a short spell of freefall
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I doubt early motion has anything to do with latter rate of descent.

Congratulations you have successfully debunked not only yourself
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ROFL. Myself ? In what way ? Who do you think you are conversing with ? :rolleyes:
 
femr2 said:
Correct. Erronious placement of the elusive T0. Effectively arbitary placement of Stage 1 end-point.


Correct(ish), though as I've said, the NIST decision to define such "staging" at all was not a good idea. They misinterpreted early motion direction, yes, but there are additional reasons why the 1.75s timing is inaccurate.


As you know, East Penthouse descent preceeded release of the NW corner (and North facade) by ~6s. Motion of the building was detectable minutes prior to release...


...and the preceeding few minutes...


Where would you suggest the "start" is ?


Further to my previous posts here, I thought I'd expand, as many folk don't tend to follow enclosed links...

NIST T0 Selection

By usage of the brightness profile in NIST Figure 12-75 the exact pixel and (interlaced) frame that NIST selected was determined...



Source Video | CBS-Net Dub7 47.avi (RAW NIST FOIA - 1Gb DV File)
Pixel | 304, 171
Frame | 5398

That point is the exact start of the NIST Stage 1.

It is also ~6s after the start of the East Penthouse descent.

The following graph shows motion of the NW corner relative to the NIST T0 and their East Penthouse release time...


As you can see, relative to NW corner motion, the NIST T0 looks pretty meaningless.

The NIST release time for the East Penthouse is also inaccurate, but that's not relevant for this thread. (It's much closer to exactly 6s prior to their T0).


NIST chose that spot with the assumption that detected motion after that point in time was vertical. In fact that motion is initially primarily North->South, as the formation of the "kink" was misinterpreted by NIST to be vertical in nature.

If they had compared the roofline profile of their chosen Cam#3 viewpoint...

...against that seen from the Dan Rather viewpoint...

...it would have been obvious that the "kink" was formed primarily North->South.

There are other ways to prove such, but comparison of the two images above (which are synchronised at the same point in time) is by far the simplest way to present the NIST interpretation error.

So, the start point of NIST "Stage 1" is, at best, flawed.

However, given that T0 (release) placement is always slightly subjective, that can be put aside, and focus can be placed upon the actual 1.75s "Stage 1" interval...


NIST Stage 1 Interval

Here is a graph of the NIST acceleration profile as derived from the equation provided, along with the Stage 1 1.75s timing...


Well, it would seem that NIST didn't derive their (time derivative of curve fit) velocity equation for acceleration, as that would put their stage 1 (which is defined by NIST as being terminated when "freefall" was attained) a little later on.

So how did they come up with the time ?

I'd suggest a guesstimate, using eye-balled velocity graph slope as a rough indicator.

Is it therefore surprising that their Stage 1 period is inaccurate ?


A more correct "Stage 1" Timing

If Stage 1 "means" the time between release and the start of the period of approximately freefall descent, then firstly acceleration profile data must be determined...



...then simply measure the time between release and maximum acceleration...

~1s

(Just before the 12s mark to just before the 13s mark)

If you want to suggest the end-point should be a little earlier (as the maximum acceleration is over "freefall", fine. That would put "Stage 1" period down to ~0.75s.

As you also know, there are a number of additional factors which affect the NIST data...

The NIST data suffers from the following (non-exhaustive) series of technical issues, each of which reduce the quality, validity and relevance of the data in various measures...

  • NIST did not deinterlace their source video. This has two main detrimental effects: 1) Each image they look at is actually a composite of two separate points in time, and 2) Instant halving of the number of frames available...half the available video data information. Tracing features using interlaced video is a really bad idea, especially for features changing vertical position. I have gone into detail on issues related to tracing of features using interlaced video data previously.
  • NIST did not sample every frame, reducing the sampling rate considerably and reducing available data redundancy for the purposes of noise reduction and derivation of velocity and acceleration profile data.
  • NIST used an inconsistent inter-sample time-step, skipping roughly every 56 out of 60 available unique images. They ignored over 90% of the available positional data.
  • NIST likely used a manual (by hand-eye) tracking process using two single pixel columns, rather than a tried and tested feature tracking method such as those provided in systems such as SynthEyes. Manual tracking introduces a raft of accuracy issues. Feature tracking systems such as SynthEyes employ an automated region-based system which entails upscaling of the target region, application of LancZos3 filtering and pattern matching (with FOM) to provide a sub-pixel accurate relative location of initial feature pattern in subsequent frames in video.
  • NIST tracked the *roofline* using a pixel column, rather than an actual feature of the building. This means that the trace is not actually of a point of the building, as the building does not descend completely vertically. This means the tracked pixel column is actually a rather meaningless point on the roofline which wanders left and right as the building moves East and West.
  • NIST chose an initial trace location which precluded starting the trace before the East Penthouse had already descended (as the East Penthouse obscured their trace location). Consequently they no way of gathering early motion data, or quantifying long term noise levels.
  • NIST chose a trace endpoint which could not be traced from their selected T0 time, and so subsequently merged data from two separate traces together, without accounting for change in scaling metric.
  • NIST used the Cam#3 viewpoint which includes significant perspective effects (such as early motion being north-south rather than up-down and yet appearing to be vertical motion). It also means that each horizontal position across the facade requires calculation of a unique scaling metric, which NIST did not bother to do.
  • NIST did not perform perspective correction upon the resultant trace data.
  • NIST did not recognise that the initial movement at their chosen pixel column was primarily north-south movement resulting from twisting of the building before the release point of the north facade.
  • NIST did not perform static point extraction (H, V). Even when the camera appears static, there is still (at least) fine movement. Subtraction of static point movement from trace data significantly reduces camera shake noise, and so reduces track data noise.
  • NIST did not choose a track point which could actually be identified from the beginning to the end of the trace, and so they needed to splice together information from separate points. Without perspective correction the scaling metrics for these two points resulted in data skewing, especially of the early motion.
  • NIST performed only a linear approximation for acceleration, choosing not to further derive their chosen displacement function.
  • NISTs displacement function, if derived to obtain acceleration/time contains a ~1s period of over-g acceleration. Whilst that in itself is fine, it's at the wrong time, and in their conclusions they ignore it.
  • NISTs displacement function, if derived to obtain acceleration/time does not suggest a 2.25s period of roughly gravitational acceleration.
  • The displacement data appears to have been extracted initially from the T0 pixel column, but using the scaling factor determined for a point above Region B, further skewing the displacement data.


As I have said many times, WTC7 was in motion several minutes prior to release. Those proposing explosives->immediate descent must ask themselves what was causing the early motion.
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Seems tfk is not really interested in discussing his thread... ?
 
This has been repeated a few times by C7 about Femr2:

"He claims to know better than the experts at NIST and a teacher with a BS in physics and a masters degree in math. He does not!"

If one removes the reference to Chandler, he sounds just like many posters here when this information was first presented.


Sounds just like TFK.


The 2 polarities, the "debunkers" here and AE911T, have much more in common than is admitted.

Both polarities taken together constitute an artificially narrowed false choice.


TFK, you can jump in at any time.
 
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http://www.internationalskeptics.com/forums/showpost.php?p=8331926&postcount=11
tfk said:
If you want, I'll happily go back there and show clearly:

1. where you intentionally quote-mined one of my postings to present an impression that was (& that you KNEW was) 180° divergent from my opinion.
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Please do.

That's called "lying", femr.
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Can you justify that slur ?

2. Where there are several blatant errors in your repeat-at-every-opportunity, tedious list of "NIST deficiencies" in their collapse timing data.
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Please do.

That's called "incompetent", femr.
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Can you justify that slur ?

3. Where you and your buddies in your 9/11 Tree house have completely screwed the pooch on your back-slapping, in-bred, rah-rah conclusion about NIST's "erroneous beginning & end of stage 1 portion" of the descent of WTC7.
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Strike-out mine. I'm not responsible for what anyone else says.

Please do.

You screwed this particular pooch because your club is comprised of a bunch of incompetents (synonymous with "Truther") & you are all way too enthusiastic about achieving a "yeah, yeah, that's right. NIST blew it" conclusion to ANY question.
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Again, I'm not responsible for what anyone else says.

By all means, please do state your case for the inflamatory remarks above.
 
http://www.internationalskeptics.com/forums/showpost.php?p=8331779&postcount=10
tfk said:
femr makes absurd claims about the precision of his subpixel resolution
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Firstly, where are these "absurd claims" ?

Accuracy estimates were performed to the same rigour as NIST included within their WTC7 moire method texts.

We've seen the comparisons to the NIST WTC7 sub-pixel traces (west edge moire method, not the awful NIST vertical displacement method) many times, so how about the WTC2 impact response...

NIST (moire method)...
131016691.jpg


femr2...


Note the displacement scale...inches.

Note the significant reduction of noise in my data.

Same thing in pixels...


All that motion is "sub pixel" Tom.

Care to dismiss the entire NIST vibration study ?

It's 1-5A 7.3.3 and the entire 1-5A Appendix K if you don't know where to look.
 
ozeco41 said:
femr2 - yours must be wrong because:

your trace is in red not blue; AND

you are femr2; AND

the sky could not be blue......;)




:boxedin:
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:)

Thought I'd replicate the sum of four decaying modes determined by NIST, and compare to my data...

d1 = [A + B(t - t0)] + Ce-D(t-t0)sin[2π(t - t0)/E + F]

521853540.jpg




They are not even the same colour !!11!1 :)
 
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Is this another of those famous f2 and mt threads that really don't belong in a 'conspiracy' subforum, because they don't propose any conspiracy?

I mean, if all it is is simply NIST bashing and patting yourselves on the back, where's the conspiracy?
 
NoahFence said:
Is this another of those famous f2 and mt threads that really don't belong in a 'conspiracy' subforum, because they don't propose any conspiracy?
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If you go back and read the original post, you'll see that this is something of a call-out thread in which tfk invited achimspok and uglypig to argue for the title of this thread. uglypig is now banned, and achimspok appears to have said everything he wants to say.

In recent posts, femr2 has been quoting tfk out of context. The quotation comes from something tfk wrote in femr2's (deliberately?) incompetent poll thread. That post is one of 21 posts in that poll thread that were moved to AAH because they responded to a derail initiated by Major_Tom. femr2 has also been omitting Note also the three things that tfk offered to show clearly. I have little doubt that tfk could show the first of those things. As for the second of those things, I personally think the majority of femr2's list is reasonably accurate, and at least one of its more tendentious items is phrased less misleadingly than in femr2's posts of last year, but I wouldn't be greatly surprised if tfk were able to identify a few errors that might qualify as "blatant". As for the third, I think both femr2 and tfk are arguing over their personal interpretations of a thing that has no truly objective definition, although the "back-slapping, in-bred, rah-rah" part sounds accurate.

In short, I think femr2 is trying to use this thread to resurrect a derail that took place in an altogether different thread and has since been moved to AAH.

NoahFence said:
I mean, if all it is is simply NIST bashing and patting yourselves on the back, where's the conspiracy?
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I guess it's a conspiracy if NIST didn't get every single detail 100% right. Odd. In my mind, or course, all I care about is that it has been shown to the satisfaction of the vast majority of experts around the world that in essence fire and damage brought the buildings down, no inside job necessary.

Those details IMO don't belong in a conspiracy forum and should reside in an engineering or scientific discussion instead.
 
NoahFence said:
Is this another of those famous f2 and mt threads that really don't belong in a 'conspiracy' subforum, because they don't propose any conspiracy?
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lol. Nope. It's a thread started by tfk with an opening line of...
tfk said:
I've set up this thread for achimspok & uglypig to make their arguments that NIST blew the calculation of the Stage 1 of WTC7 collapse.
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I've presented a fairly detailed short technical response.
 
W.D.Clinger said:
In recent posts, femr2 has been quoting tfk out of context.
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Nope. Directly about this thread topic.

Note also the three things that tfk offered to show clearly. I have little doubt that tfk could show the first of those things. As for the second of those things, I personally think the majority of femr2's list is reasonably accurate, and at least one of its more tendentious items is phrased less misleadingly than in femr2's posts of last year, but I wouldn't be greatly surprised if tfk were able to identify a few errors that might qualify as "blatant". As for the third, I think both femr2 and tfk are arguing over their personal interpretations of a thing that has no truly objective definition, although the "back-slapping, in-bred, rah-rah" part sounds accurate.
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I have simply invited tfk to do what he said he was happy to do ("I'll happily go back there and show clearly...")

Please do, tfk.

Also, W.D.Clinger, if you want to highlight what you think are errors, then do so. No point keeping them to yourself now, is there ?

I'll add that in the process he also added accusation of me "lying" and being "incompetent" within this thread.

He should back up such accusations with the politely requested response.

In short, I think femr2 is trying to use this thread to resurrect a derail that took place in an altogether different thread and has since been moved to AAH.
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You think wrong.
 
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femr2 said:
lol. Nope. It's a thread started by tfk with an opening line of...


I've presented a fairly detailed short technical response.
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I'm well aware of how it started.

I'm talking about what it is now. Sexy graphs and charts, no substance. No conclusions.

NIST is wrong.

FEMR is right.

rinse and repeat.
 
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