Items tagged with: rejection
“Boeing 737 Max: What went wrong?” (BBC) contains a plot showing the angle of attack data being fed to Boeing’s MCAS software. Less than one minute into the flight, the left senso…
Article word count: 275
HN Discussion: https://news.ycombinator.com/item?id=19627490
Posted by VBprogrammer (karma: 2419)
Post stats: Points: 108 - Comments: 121 - 2019-04-10T18:31:56Z
#HackerNews #737 #and #boeing #crash #data #max #rejection #ridiculous #the
“Boeing 737 Max: What went wrong?” (BBC) contains a plot showing the angle of attack data being fed to Boeing’s MCAS software. Less than one minute into the flight, the left sensor spikes to an absurd roughly 70-degree angle of attack. Given the weight of an airliner, the abruptness of the change was impossible due to inertia. But to have avoided killing everyone on board, the software would not have needed a “how fast is this changing?” capability. It would simply have needed a few extra characters in an IF statement. Had the systems engineers and programmers checked Wikipedia, for example, (or maybe even their own web site) they would have learned that “The critical or stalling angle of attack is typically around 15° – 20° for many airfoils.” Beyond 25 degrees, therefore, it is either sensor error or the plane is stalling/spinning and something more than a slow trim is going to be required.
So, even without checking the left and right AOA sensors against each other (what previous and conventional stick pusher designs have done), all of the problems could potentially have been avoided by changing
IF AOA > 15 THEN RUNAWAY_TRIM();
IF AOA > 15 AND AOA < 25 THEN RUNAWAY_TRIM();
About 10 characters of code, in other words.
We fret about average humans being replaced by robots, but consider the Phoenix resident who sees that the outdoor thermometer is reading 452 degrees F on a June afternoon. Will the human say “Arizona does get hot in the summer so I’m not going to take my book outside for fear that it will burst into flames”? Or “I think I need to buy a new outdoor thermometer”?
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The scientific method relies on facts, established through repeated measurements and agreed upon universally, independently of who observed them. In quantum mechanics, the objectivity of observations…
Article word count: 146
HN Discussion: https://news.ycombinator.com/item?id=19404873
Posted by lisper (karma: 32554)
Post stats: Points: 124 - Comments: 62 - 2019-03-15T22:23:21Z
#HackerNews #experimental #observer-independence #quantum #rejection #the #world
(Submitted on 13 Feb 2019)
Abstract: The scientific method relies on facts, established through repeated measurements and agreed upon universally, independently of who observed them. In quantum mechanics, the objectivity of observations is not so clear, most dramatically exposed in Eugene Wignerʼs eponymous thought experiment where two observers can experience fundamentally different realities. While observer-independence has long remained inaccessible to empirical investigation, recent no-go-theorems construct an extended Wignerʼs friend scenario with four entangled observers that allows us to put it to the test. In a state-of-the-art 6-photon experiment, we here realise this extended Wignerʼs friend scenario, experimentally violating the associated Bell-type inequality by 5 standard deviations. This result lends considerable strength to interpretations of quantum theory already set in an observer-dependent framework and demands for revision of those which are not.
From: Martin Ringbauer PhD [view email]
[v1]Wed, 13 Feb 2019 19:00:07 UTC (1,967 KB)
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