6 ms·

That happens in Olympic Games https://www.olympic.org/news/double-gold-medal-joy-as-oleksiak-and-manuel-finish-in-dead-heat https://www.olympic.org/news/double

by cesis 5y ago

That happens in Olympic Games https://www.olympic.org/news/double-gold-medal-joy-as-oleksiak-and-manuel-finish-in-dead-heat https://www.olympic.org/news/double-gold-medal-joy-as-oleksi...

doikor 5y ago
This happens in swimming because of the tolerance of making an olympic spec pool. A good swimmer goes a bit over 2mm every 0.001s. The pools have 3cm tolerance meaning the lanes are not the exact same length (it would be crazy expensive to make pools to smaller tolerances) So to solve this they just don't measure beyond hundreds (no human can swim fast enough that the distance they travel within 0.01s could make a difference). And thus can not use photo finish either as again the lanes are not guaranteed to be the same length. https://interestingengineering.com/significant-digits-and-pool-tolerances-are-why-there-are-so-many-ties-in-swimming https://interestingengineering.com/significant-digits-and-po... edit: In other sports like running it is easy to have accurate track length as you just paint the lines after building the track so you can have it as accurate as you want (+photo finish). In swimming it just does not work like that.
- xxs 5y ago
  Swimming is worse than that as the inner lanes have inherent advantage of less water drag as the waves bounce off the walls. Of course inner lanes are seeded with the fastest timings from the previous heat.
  - doikor 5y ago
    This is why modern competition pools are 10 lanes wide but only the inner 8 are used in competitions.
- Ichthypresbyter 5y ago
  Exactly- in a few days earlier, Mahe Drysdale of New Zealand won gold in the men's single sculls after being maybe a centimetre ahead of Damir Martin of Croatia at the line: https://www.telegraph.co.uk/content/dam/news/2016/08/13/drysdale_photo_finish_trans_NvBQzQNjv4BqtR1WRZ4lb6BOb1-FBRpn-lFGGjcI28awSNtOPAVs6pc.png https://www.telegraph.co.uk/content/dam/news/2016/08/13/drys... (Drysdale is in the black boat).
- eru 5y ago
  Well, they could have everyone swim one after another in the same lane. It's not like there's much interaction between racers, as there is eg in a boxing match. (Of course, this would totally ruin the sport for spectators. Following this logic, for any sport with no interaction, everyone could just stay home and run around their own track whenever they feel like and just send in their times to a central record keeper.)
  - xxs 5y ago
    Having a competitor next to you provides a stronger absolute result. It's believed to be a standard natural selection/evolution effect. Even pain tolerances increase.
    - usrusr 5y ago
      Also conditions change over time. Indoor pools are much less affected than e.g. a ski run in inclement weather or ski flying where competitions are basically lotteries in who gets a favorable gust, but subtle changes in e.g. air oxygen content could easily cause performance differences in the range we are talking about here.
      - xxs 5y ago
        >ski flying where competitions are basically lotteries in who gets a favorable gust That has always bothered me that there are some calculations/arbitrary numbers based on the wind... to a point the length of the ramp gets adjusted. I recall when the V shape was introduced, initially it was shunned by the judges for bad style (negative points), regardless it was obviously aerodynamically better. However, swimming would also be affected as the water temperature won't be constant either.
        eru 5y ago
        Many swimming competitions are indoors, so water temperature can be adjusted to a standard easily for them. (But you are right about outdoor pools. They are much more of a hassle to adjust the temperature for.)
- Someone 5y ago
  That still doesn’t guarantee that the winner was the fastest. Let’s say real times were 58.994999 and 58.995000 seconds. The first gets registered as 58.99, the second as 59.00. Actual difference is a millionth of a second, or, at 2 meters a second, 2μm. I think they do this in swimming more because swimmers, certainly at shorter distances, more race themselves than their competitors. That’s a huge difference with road cycling, where typically the front riders in a sprint could get over the finish earlier, if they wanted to, but don’t want to do that, as, if they did that, their competition would tail them up to the last few meters and then jump over them. Rowing is somewhat of a middle ground. They do use finish photos, even though there’s the same. “Tracks aren’t guaranteed to be the same length” problem as in swimming. A famous example is the men’s scull final in the 2016 Olympics: https://www.olympicchannel.com/en/video/detail/mahe-drysdale-wins-single-sculls-gold-after-photo-finish/ https://www.olympicchannel.com/en/video/detail/mahe-drysdale... I don’t understand why you think it’s easy to have accurate track length in running. Temperature may affect track length. A lot more importantly, I don’t think it’s even doable in events where runners all start in their own track but are allowed to move to the inner track after x meters. But again, it’s less important there because runners race against each other there more than in short swim races.
  - xxs 5y ago
    >Let’s say real times were 58.994999 and 58.995000 seconds. How do you achieve a million frames per second? Even analog input (like touching - which would be capacitive [hence more tolerances]) will have a very hard time registering that, just based on cable and PCB traces length, temperature differences (which affect silicon and resistance in general). 7 digit precision is a non-trivial task for non-controlled environment. For example 8.5 digit voltmeters take one 1 minute for a single measurement and they have to have extremely good temperature controls. Then for the microsecond precision you have to consider the speed of sound just to propagate to participants to hear the gun.
    - sokoloff 5y ago
      They’re not hypothesizing a measurement device recording those times and then rounding. They’re just setting up a “let’s take as a given that this is what really happened in the world” and asking what errors our processes could do if we do a series of imprecise measurements and then compare those measurements. Side note: my HP 3458A can do a small handful of 8.5 digit DCV measurements per second.
- tzs 5y ago
  > This happens in swimming because of the tolerance of making an olympic spec pool. A good swimmer goes a bit over 2mm every 0.001s. The pools have 3cm tolerance meaning the lanes are not the exact same length (it would be crazy expensive to make pools to smaller tolerances). It would be crazy expensive to make the pools to such a small tolerance, perhaps, but it is not the length of the pool that actually counts, is it? It is the distance to the touch pad that counts. Would it be crazy expensive to make the touch pad mounting system adjustable so that the position of each lane's pad could be adjusted to millimeter or even sub-millimeter tolerances?
  - doikor 5y ago
    Main problem is old pools that don't have space for this (would make the pool under length). In general the same rules are used in all levels of competition. The only difference at the moment is minimum pool depth for world championships and olympics which is a bit deeper. But yes in general new competition pools are built to be slightly larger than 50m and you just adjust the pads at the ends.
  - opwieurposiu 5y ago
    You could equalize the length of the lanes, but there are water currents that give different lanes "headwinds" or "tailwinds". These are caused by the pumps, wave action, and thermal convection.
  - toast0 5y ago
    Many swim races are more than one lap, so you would have to adjust the touch pads for lap count.

by cesis 5y ago

That happens in Olympic Games https://www.olympic.org/news/double-gold-medal-joy-as-oleksiak-and-manuel-finish-in-dead-heat https://www.olympic.org/news/double-gold-medal-joy-as-oleksi...

doikor 5y ago

This happens in swimming because of the tolerance of making an olympic spec pool. A good swimmer goes a bit over 2mm every 0.001s. The pools have 3cm tolerance meaning the lanes are not the exact same length (it would be crazy expensive to make pools to smaller tolerances) So to solve this they just don't measure beyond hundreds (no human can swim fast enough that the distance they travel within 0.01s could make a difference). And thus can not use photo finish either as again the lanes are not guaranteed to be the same length. https://interestingengineering.com/significant-digits-and-pool-tolerances-are-why-there-are-so-many-ties-in-swimming https://interestingengineering.com/significant-digits-and-po... edit: In other sports like running it is easy to have accurate track length as you just paint the lines after building the track so you can have it as accurate as you want (+photo finish). In swimming it just does not work like that.

xxs 5y ago
Swimming is worse than that as the inner lanes have inherent advantage of less water drag as the waves bounce off the walls. Of course inner lanes are seeded with the fastest timings from the previous heat.
- doikor 5y ago
  This is why modern competition pools are 10 lanes wide but only the inner 8 are used in competitions.
Ichthypresbyter 5y ago
Exactly- in a few days earlier, Mahe Drysdale of New Zealand won gold in the men's single sculls after being maybe a centimetre ahead of Damir Martin of Croatia at the line: https://www.telegraph.co.uk/content/dam/news/2016/08/13/drysdale_photo_finish_trans_NvBQzQNjv4BqtR1WRZ4lb6BOb1-FBRpn-lFGGjcI28awSNtOPAVs6pc.png https://www.telegraph.co.uk/content/dam/news/2016/08/13/drys... (Drysdale is in the black boat).
eru 5y ago
Well, they could have everyone swim one after another in the same lane. It's not like there's much interaction between racers, as there is eg in a boxing match. (Of course, this would totally ruin the sport for spectators. Following this logic, for any sport with no interaction, everyone could just stay home and run around their own track whenever they feel like and just send in their times to a central record keeper.)
- xxs 5y ago
  Having a competitor next to you provides a stronger absolute result. It's believed to be a standard natural selection/evolution effect. Even pain tolerances increase.
  - usrusr 5y ago
    Also conditions change over time. Indoor pools are much less affected than e.g. a ski run in inclement weather or ski flying where competitions are basically lotteries in who gets a favorable gust, but subtle changes in e.g. air oxygen content could easily cause performance differences in the range we are talking about here.
    - xxs 5y ago
      >ski flying where competitions are basically lotteries in who gets a favorable gust That has always bothered me that there are some calculations/arbitrary numbers based on the wind... to a point the length of the ramp gets adjusted. I recall when the V shape was introduced, initially it was shunned by the judges for bad style (negative points), regardless it was obviously aerodynamically better. However, swimming would also be affected as the water temperature won't be constant either.
      - eru 5y ago
        Many swimming competitions are indoors, so water temperature can be adjusted to a standard easily for them. (But you are right about outdoor pools. They are much more of a hassle to adjust the temperature for.)
Someone 5y ago
That still doesn’t guarantee that the winner was the fastest. Let’s say real times were 58.994999 and 58.995000 seconds. The first gets registered as 58.99, the second as 59.00. Actual difference is a millionth of a second, or, at 2 meters a second, 2μm. I think they do this in swimming more because swimmers, certainly at shorter distances, more race themselves than their competitors. That’s a huge difference with road cycling, where typically the front riders in a sprint could get over the finish earlier, if they wanted to, but don’t want to do that, as, if they did that, their competition would tail them up to the last few meters and then jump over them. Rowing is somewhat of a middle ground. They do use finish photos, even though there’s the same. “Tracks aren’t guaranteed to be the same length” problem as in swimming. A famous example is the men’s scull final in the 2016 Olympics: https://www.olympicchannel.com/en/video/detail/mahe-drysdale-wins-single-sculls-gold-after-photo-finish/ https://www.olympicchannel.com/en/video/detail/mahe-drysdale... I don’t understand why you think it’s easy to have accurate track length in running. Temperature may affect track length. A lot more importantly, I don’t think it’s even doable in events where runners all start in their own track but are allowed to move to the inner track after x meters. But again, it’s less important there because runners race against each other there more than in short swim races.
- xxs 5y ago
  >Let’s say real times were 58.994999 and 58.995000 seconds. How do you achieve a million frames per second? Even analog input (like touching - which would be capacitive [hence more tolerances]) will have a very hard time registering that, just based on cable and PCB traces length, temperature differences (which affect silicon and resistance in general). 7 digit precision is a non-trivial task for non-controlled environment. For example 8.5 digit voltmeters take one 1 minute for a single measurement and they have to have extremely good temperature controls. Then for the microsecond precision you have to consider the speed of sound just to propagate to participants to hear the gun.
  - sokoloff 5y ago
    They’re not hypothesizing a measurement device recording those times and then rounding. They’re just setting up a “let’s take as a given that this is what really happened in the world” and asking what errors our processes could do if we do a series of imprecise measurements and then compare those measurements. Side note: my HP 3458A can do a small handful of 8.5 digit DCV measurements per second.
tzs 5y ago
> This happens in swimming because of the tolerance of making an olympic spec pool. A good swimmer goes a bit over 2mm every 0.001s. The pools have 3cm tolerance meaning the lanes are not the exact same length (it would be crazy expensive to make pools to smaller tolerances). It would be crazy expensive to make the pools to such a small tolerance, perhaps, but it is not the length of the pool that actually counts, is it? It is the distance to the touch pad that counts. Would it be crazy expensive to make the touch pad mounting system adjustable so that the position of each lane's pad could be adjusted to millimeter or even sub-millimeter tolerances?
- doikor 5y ago
  Main problem is old pools that don't have space for this (would make the pool under length). In general the same rules are used in all levels of competition. The only difference at the moment is minimum pool depth for world championships and olympics which is a bit deeper. But yes in general new competition pools are built to be slightly larger than 50m and you just adjust the pads at the ends.
- opwieurposiu 5y ago
  You could equalize the length of the lanes, but there are water currents that give different lanes "headwinds" or "tailwinds". These are caused by the pumps, wave action, and thermal convection.
- toast0 5y ago
  Many swim races are more than one lap, so you would have to adjust the touch pads for lap count.