[HN Gopher] Mathematical Optimization for Cargo Ships
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Mathematical Optimization for Cargo Ships
Author : alphabetting
Score : 66 points
Date : 2024-06-05 00:00 UTC (22 hours ago)
(HTM) web link (research.google)
(TXT) w3m dump (research.google)
| algo_trader wrote:
| Apparently, container optimization was unsolved for very large
| fleets. I did not know this.
|
| Google OR improves existing solutions by 10%-20% utilization
| which is incredible.
| smarm52 wrote:
| It sounds like a packing problem. I'm not deeply familiar with
| the field, but I don't believe there is a general solution.
|
| https://en.wikipedia.org/wiki/Packing_problems
| hermitcrab wrote:
| Optimally placing containers on ships must be a very
| difficult problem. Consider you might want:
|
| -heavier containers at the bottom for stability
|
| -refrigerated containers on the inside to reduce heat loss
|
| -containers to be unloaded first near the top
|
| etc
|
| And all in 3 dimensions!
| IncreasePosts wrote:
| All of the refrigerated containers I have seen have had a
| built in generator/AC unit...why would shippers care about
| heat loss, unless they are providing the energy to
| refrigerate the containers?
| hermitcrab wrote:
| I assume the shippers are providing the power for
| refrigerated containers. Otherwise they would need to
| have batteries or fuel that could last potentially weeks
| at sea. Anyone know?
| ianburrell wrote:
| Container ships do provide power to refrigerated
| containers. My understanding is that refrigerated
| containers are in row with the door accessible and power
| hookup. I was looking at photo of the row, and how
| container ships have extra power system to power them. It
| looked like it was far down with stacks of containers
| around and presumably on top.
| akira2501 wrote:
| That generator is for very short periods of time spent in
| transit. Once it's on the ship it's directly connected to
| ships power. This also has implications for it's
| placement as not all rows of stacks on a ship have power
| cables run out to them.
|
| Also, because of the short time requirement, and some
| extreme low temperature requirements on some cargo, it
| needs to be in a place where it can be disconnected and
| very quickly craned off the ship.
|
| The engineer making and breaking the connections will
| generally have to manually log the time of these actions
| and the time of the unload. It's all a very interesting
| and somewhat complicated process.
| Terr_ wrote:
| > -heavier containers at the bottom for stability
|
| In the same vein, port /starboard / bow / stern balance.
|
| > -containers to be unloaded first near the top
|
| Containers with the same destination in separate places so
| that multiple cranes can run in parallel without infringing
| on each other's work-zones.
| xnx wrote:
| I don't think this relates to the physical loading of the
| containers on ships at all. It is concerned with 3 problems:
| "Network design determines the order in which vessels visit
| ports, network scheduling determines the times they arrive
| and leave, and container routing chooses the journey that
| containers take from origin to destination."
| 3abiton wrote:
| This is big news for supply chains!
| whimsicalism wrote:
| I am very curious if anyone will actually use this API endpoint
| they're releasing
| https://developers.google.com/optimization/service/shipping/...
|
| It's very cool nonetheless
| mcint wrote:
| Probably it'd be irresponsible not to try it. I'm curious if
| this is the full shape of the problems and constraints faced by
| planners. Flexport is the $3.3bn (revenue) company in this
| space also based in SF.
| whimsicalism wrote:
| oh yes i remember them! - they were the first company to
| reject me for a job
| malfist wrote:
| Don't worry, they imported an Amazon exec who laid waste to
| the culture, set everything on fire, didn't accomplish
| anything and then was fired. You know, the typical amazon
| exec.
| mcint wrote:
| I still wonder about stowage plans for these. I guess t's the
| next level down to solve approximately after the route plan for
| each container. They come later and have constraints that are
| more contingent than the global system level view.
|
| Ballpark, optimistically, shore cranes can do 30-50 moves per
| hour, 2 or 4, maybe 6 cranes per vessel, and you have to unpack
| shell layer by layer.
|
| * Ultra Large Container Vessel (ULCV): 14,501 TEU and higher
|
| * New Panamax: 10,000-14,500 TEU
|
| * Post-Panamax: 5,101-10,000 TEU
|
| * Panamax: 3,001-5,100 TEU
|
| 24,000 TEU (Twenty-foot Equivalent Units), say 12k 40-foot
| containers 4 cranes * 50 containers/crane-hour *
| 24 hours/day = 1.2k containers / day
|
| https://en.wikipedia.org/wiki/Stowage_plan_for_container_shi...
|
| Stowage plans for ships also have weight, balance, power, and
| value acceptability criteria beyond availability at a port.
|
| These overheads made me curious enough to write up some napkin
| math, since they mention cut-and-run early departures from ports.
| akasakahakada wrote:
| Make me think of every shopowner or manager of local restaurants
| or something said they had headache planning schedule for part-
| time employees. Some even say that is the reason they are paid
| well. I thought, but why don't you just use some algorithms to
| solve it?
| spankalee wrote:
| The same Operations Research group has scheduling examples for
| restaurants:
| https://developers.google.com/optimization/service/schedulin...
| thinkingkong wrote:
| This seems pretty incredible but Im mostly surprised Google is
| dipping their toes into this domain at all. Feels fairly outside
| the Google wheelhouse. I could understand Alphabet having another
| company provide this kind of functionality but it just seems out
| of place.
|
| Who are they competing with?
| spankalee wrote:
| I wouldn't think of this as a full-fledged business yet, but as
| a way for the Operations Research team to get their work tried
| out in the real world.
|
| If they're really improving the state-of-the-art, to the degree
| that real money is saved, and the industries are big enough,
| these APIs will probably get used a lot and moved out of
| research or licensed.
| rapfaria wrote:
| It is really worth a try when demurrage is not even accounted
| for?
|
| https://developers.google.com/optimization/service/reference...
| snapetom wrote:
| I'm in the terminal side of this business. While this seems very
| interesting, and I'm sure some line will poke at it, it seems
| very academic. I'm curious if they actually partnered with a
| shipping line to come up with this.
|
| On the terminal side, all I can say is that I am knee-deep in
| container optimizations right now and it's a damn nightmare.
| Every terminal does things extremely differently, even if the
| terminal is owned by the same company. Even the terminology is
| often different within a company. You optimize for one terminal,
| and you have to build 80% of it from scratch for the next
| terminal. Any solution is incredibly difficult to scale.
| nickff wrote:
| I'm very curious about what you folks do! How much effort is
| expended on this optimization? Perhaps in terms of FTE
| developers per terminal.
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