5 ms·

Or build sufficient back pressure mechanisms so that the cargo doesn’t get loaded in the first place or better still the goods doesn’t get manufactured and so o

Or build sufficient back pressure mechanisms so that the cargo doesn’t get loaded in the first place or better still the goods doesn’t get manufactured and so on. Send the feedback as far up the source as possible.

kqr 5y ago
Right, and now you're using the argument of the top level comment. Look at the port. Is ingress consistently larger than egress? Then limit ingress. Now look at the ocean. Is ingress consistently larger than egress? Then limit ingress. Now look at the exporting ports. Is ingress consistently larger than egress? Limit ingress. Now look at trucks going to the port. Is ingress consistently larger than egress? Limit ingress. Now look at the factories that load trucks. Is ingress consistently larger than egress? Limit ingress. ---- Back pressure builds on looking at one queue and asking if arrivals come faster than departures go -- exactly what the top-level comment suggested.
simonh 5y ago
The problem there is signal lag. When the backlog at the port is cleared and you signal the factory to start production again, it might take 3 months for the products to start arriving at the port again. If the port gets congested again and you stop production it might take a month for the goods already made and on their way to stop arriving. But you can also redirect cargo to different ports, or increase the price you charge for servicing cargo. Even if you dump containers you don’t have to do so randomly. Customers could even mark containers as rejectable, or non critical and therefore first to go to a backlog for a discount. I found the article really interesting. For most IT use cases jobs are generic but thanks for raising the port example.
- btilly 5y ago
  The signal lag is a huge problem. When you go a few stages through a supply chain, a gradual variation in consumer demand turns into huge whiplashes in demand. This is called "the bullwhip effect" and is a huge problem in supply chain management. See https://www.cips.org/knowledge/procurement-topics-and-skills/operations-management/bullwhip-effect-in-supply-chain/ https://www.cips.org/knowledge/procurement-topics-and-skills... for more.
gpderetta 5y ago
AKA "there are no truly unbounded queues, only queues you do not know the bounds yet". Back Pressure is good (but also hard).

kqr 5y ago

Right, and now you're using the argument of the top level comment. Look at the port. Is ingress consistently larger than egress? Then limit ingress. Now look at the ocean. Is ingress consistently larger than egress? Then limit ingress. Now look at the exporting ports. Is ingress consistently larger than egress? Limit ingress. Now look at trucks going to the port. Is ingress consistently larger than egress? Limit ingress. Now look at the factories that load trucks. Is ingress consistently larger than egress? Limit ingress. ---- Back pressure builds on looking at one queue and asking if arrivals come faster than departures go -- exactly what the top-level comment suggested.

simonh 5y ago

The problem there is signal lag. When the backlog at the port is cleared and you signal the factory to start production again, it might take 3 months for the products to start arriving at the port again. If the port gets congested again and you stop production it might take a month for the goods already made and on their way to stop arriving. But you can also redirect cargo to different ports, or increase the price you charge for servicing cargo. Even if you dump containers you don’t have to do so randomly. Customers could even mark containers as rejectable, or non critical and therefore first to go to a backlog for a discount. I found the article really interesting. For most IT use cases jobs are generic but thanks for raising the port example.

btilly 5y ago
The signal lag is a huge problem. When you go a few stages through a supply chain, a gradual variation in consumer demand turns into huge whiplashes in demand. This is called "the bullwhip effect" and is a huge problem in supply chain management. See https://www.cips.org/knowledge/procurement-topics-and-skills/operations-management/bullwhip-effect-in-supply-chain/ https://www.cips.org/knowledge/procurement-topics-and-skills... for more.

gpderetta 5y ago

AKA "there are no truly unbounded queues, only queues you do not know the bounds yet". Back Pressure is good (but also hard).