Actually I think that GeoGebra is by far the most intuitive and for-the-people that a math toolbox can be. When I picked it up in Highschool, I didn’t need to google a thing about it, contrary to the CAS Systems I use nowadays... (Maybe not a fair comparison)
Except that there's no "I don't understand" button where you can tell the author what you don't understand. So it's basically a one-way textbook with no feedback mechanism for the author to discover his assumptions and clarify them.
Also did this in cryptography + coding theory class back in university days.
Our final exam had a practical code breaking test where we had a bunch of utilities and had to crack 3 different cyphers. I've always recounted it fondly.
That’s a bullshit argument. My SO‘s Lenovo Laptops USB A ports broke. My USB-C Ports seem significantly more robust, not by implementation but by design. I don’t care about some five dollar China dongle- I care about the connectors of my computer and in this regard there is not a single connector that can compete with USB-C.
I said "That's why I no longer have a Mac and have a Windows laptop instead." It's not an argument. It's simply a statement of fact that explains a choice I've made for myself.
I literally switched from a user serviceable Mac laptop with plenty of ports (15" 2011 MBP) to user serviceable PC laptops with plenty of ports, with one of the primary reasons being that the newer Macbook models didn't satisfy my desire to have a full suite of ports that includes ethernet.
As for broken ports/connectors, I've had zero port failures in almost 3 decades of laptop ownership, and I don't consider myself to be very gentle plugging/unplugging my peripherals.
At the moment, I have 2 laptops with USB-C and 3 without. I personally don't see a huge difference in robustness between the USB-C and USB-A ports. Even when I buy a USB-C laptop, I still make sure that it still has at least one USB-A port so I can have dongle-free interoperability with my peripherals.
You can't compensate because you don't know which one is wrong. However you can make MCAS inactive whenever the two sensors are disagreeing with each other.
This is why the parent poster is arguing for 3 sensors (and the real reason for tripling). If not all sensors agree but 2/3 do, it is more probable that the two sensors are correct than the 1 sensor disagreeing.
Right, but the MCAS system as it was implemented during those two crashes did not disable itself when the two sensors disagreed. It could have, but didn't. Boeing is apparently changing that, and I believe that change to be sufficient.
MCAS being automatically disabled when the sensors agree but leaving the pilots with electronic trim control seems like a perfectly adequate solution. The MCAS system was never even necessary for flight, it was only necessary for certification. In the situations where it's meant to be active, which are a limited subset of all high angle of attack scenarios, it's fine system to have if it's working correctly. But it should never be active outside of that limited set of scenarios. It should never be active when both angle of attack sensors aren't indicating a high angle of attack within a reasonable distance of each other.
Frankly, if two sensors are indicating a high angle of attack and one is not, it's probably still sensible to disable MCAS. I don't have any of the real numbers, but the chance of a 737 being in a low speed high angle of attack scenario is low in the first place, possibly sufficiently low that "two sensors being wrong and the aircraft being in level flight" might be more likely than "aircraft is near stall and one sensor is wrong."
To know for sure we'd need at least the hard data on what modes of failure these sensors have, how likely any of those modes is to occur and what the expected readouts from those failure modes are, and how likely a 737 is to encounter a low speed stall scenario. We, or at least I, don't have any of that. But my gut says that two sensors are sufficient iff the MCAS system is only active when they agree.
Furthermore, the chance of two sensors being wrong actually goes up if you have three sensors, rather than two. Correct me if I'm wrong, stats was never my strong point, but it seems to me like the cumulative binomial distribution is relevant here:
#lang racket
(require math/number-theory)
(define (general-binomial p k n)
(* (binomial n k)
(expt p k)
(expt (- 1 p)
(- n k))))
(define (cumulative-general-binomial p k1 k2 n)
(apply +
(map
(λ (k) (general-binomial p k n))
(range k1 (add1 k2)))))
Chance of a single sensor failing, if each has a 1% chance of failure (sanity check):
> (cumulative-general-binomial .01 1 1 1)
0.01
Chance of two or three out of three sensors failing, if each has a 1% chance of failure:
MCAS should turn off as soon as a single sensor fails, and three sensors are therefore unnecessary. Two sensors are sufficient to detect when a single sensor fails. If you only have two sensors and two fail, then MCAS remains active and your plane crashes. But that's not likely to happen. However that's more likely to happen if you have three sensors and try to use two sensors to vote out a third, in order to keep MCAS active when a sensor fails. In that configuration, a double failure (causing a crash) is three times more likely.
My conclusion is turn off MCAS as soon as even one sensor disagrees with the others. And if that's how MCAS is configured, then three sensors is unnecessary overkill. If you want overkill, you may as well double up the sensors on both sides and have four instead of three; all the better right?
Eh, that kind of makes a certain amount of sense, but I don't think that's quite right. Determining which of the two sensors is less-extreme supposes knowledge about the airframe's current state. If he aircraft is currently in a very high angle of attack low speed stall, then the sensor that says everything is A-Okay is the extreme sensor.
I understand that's not what you mean, that the sensor indicating a situation closes to nominal flight should be chosen, but I think the sticky part is that MCAS isn't a system meant for normal flight conditions. MCAS is only supposed to be active when the aircraft is in an extreme scenario. So in fact if the sensor with "less-extreme adjustment" is preferred, in a way that actually means the system functions as I suggested: MCAS is disabled if the sensors disagree. But not quite. In your scheme if both the sensors are extreme but disagree, MCAS would be active to the lesser extent. But in my scheme, if both sensors are extreme but disagree, MCAS would be totally inactive (while leaving the pilot with electronic stabilizer trim control of course, allowing the pilot to manually do anything MCAS would be capable of doing.)
The environmental Argument is interesting as I am thinking about getting AirPods precisely because Im sick of throwing away my regular in Ears because the headphone jacks keep breaking when I carry them crumbled in my jeans. (I hate having them tangle around while not in use). As an earlier poster pointed out: It all depends on your use case and preferences.
Shure, and many other good companies, make earphones with removable cables. These MMCX cables can be bought relatively cheaply (decent ones on Amazon france seem to be about EUR 15 onwards). Even better, the ones that come with the earphones are burly as fuck, and as I said, mine have lasted three years with no damage or loose soldering to report.
I did a review of Shure in ear monitors. They sent me their entire product lineup, though I only reviewed two of their products. The highest priced monitor had a cable break 2 years later, with only minimal use in that period. They had/have outstanding customer support for this class of monitor, and replaced it for free. Cable broke 6 months later. They would have replaced that too, but I didn't pay for the monitors, and felt like it was right to push it. These are the type of in ear monitors musicians use on stage during performances, and easily run of $1k. They sounded fantastic, but they were as reliable as Apple's $30 corded airbuds.
Don't know what to tell you, except my experience didn't match yours. The only special thing I do to care for them is to fold them in figure-of-eights so that there isn't much stress on the cables when stowed. They've gotten caught in doorknobs etc. during my time of owning them, but still going strong.
I think one of the basics ways for us to combat this kind of situations is to be more mindful about the people who do good. A single, thankful email from someone who profited from his work goes a long way.
