Some Robocar updates, since with Burning Man and Singularity U my posting volume has been down:

Today an op-ed by John Sununu and Harold Ford Jr. of "Broadband For America" (a group of cable companies and other ISPs which says it is really a grass-roots organization) declared that the net needs a better pricing model for what Netflix is doing. For a group of ISPs, they really seem to not understand how the internet works and how pricing works, so I felt it was worthwhile to describe how things work with a remarkably close analogy. (I have no association with Netflix, I am not even a customer, but I do stream video on the net.)

You can liken the internet to a package delivery service that works somewhat differently from traditional ones like the postal service or FedEx. The internet's pricing model is "I pay for my line to the middle, and you pay for your line to the middle and we don't account for the costs of individual traffic."

In the package model, imagine a big shipping depot. Shippers send packages to this depot, and it's the recipient's job to get the package from the depot to their house. The shippers pay for their end, you pay for your end, and both share the cost of creating the depot.

Because most people don't want to go directly to the depot to get their packages, a few "last mile" delivery companies have sprung up. For a monthly fee, they will deliver anything that shows up at the depot addressed to you directly to your house. They advertise in fact, that for the flat fee, they will deliver as many packages as show up, subject to a fairly high maximum rate per unit of time (called bandwidth in the internet world.) They promote and compete on this unlimited service.

To be efficient, the delivery companies don't run a private truck from the depot to your house all the time. Instead, they load up a truck with all the packages for your neighbourhood, and it does one delivery run. Some days you have a lot of packages and your neighbours have few. Other days you have few and they have a lot. The truck is sized to handle the high end of the total load for all the neighbours. However, it can't handle it if a large number of the neighbours all want to use a large fraction of their total load on the same day, they just didn't buy enough trucks for that, even though they advertised they were selling that.

This is not unreasonable. A majority of the businesses in the world that sell flat rate service work this way, not just internet companies. Though there are a few extra twists in this case:

• The last mile companies have a government granted franchise. Only a couple can get permission to operate. (In reality -- only a few companies have got permission to have wires strung on poles or under the street.)
• Some of the last mile companies also used to be your exclusive source for some goods (in this case phone service and TV) and are concerned that now there are competitors delivering those things to the customers.

The problem arises because new services like Netflix suddenly have created a lot more demand to ship packages. More than the last mile companies counted on. They're seeing the truck fill up and need to run more trucks. But they proudly advertised unlimited deliveries from the depot to their customers. So now, in the op-ed, they're asking that companies like Netflix, in addition to paying the cost of shipping to the depot, pay some of the cost for delivery from the depot to the customer. If they did this, companies would pass this cost on to the customer, even though the customer already paid for that last mile delivery.

Tuesday we and Aneesh Chopra, CTO of the USA come to Singularity University and among many things, he was asked about immigration. (In part because our class comes from 35 countries and many of them would love to be entrepreneurs in the USA.) Chopra announced some immigration rule clarifications that had come out that day which will help things somewhat. They did rule clarifications because getting congress to do meaningful reform is very hard.

This is a challenge to blog readers to come up with (or find examples in practice) of good systems to allocate students to parallel sessions based on their preferences. I've just concluded one round of this, and the bidding system I built worked OK, but is not perfect.

The problem: Around 80 students. On 10 days over 4 weeks they will be split into 3-5 different parallel sessions on those days. Many sessions have a cap on the number of students, and more students will have them as a 1st choice than can fit. Some sessions can take many students and won't fill up. The students can express their preference as ranking, or with numeric values.

This is known in the literature as the Allocation problem, and there are various approaches, though none I found seemed to fit just right, either being easy to code or having existing running code. But I am keen on pointers.

The goals:

• Maximize student satisfaction/minimize disappointment. Giving a student their 1st choice is good. Giving 3rd or 4th choices is bad.
• The system must be easy for the students to understand and use.
• Fairness. This has many meanings, but ideally mismatches that can't be avoided should be distributed. If somebody gets a 4th choice one day, they perhaps should have a better shot at a 1st choice on another day.
• It's nice if there's a means of applying penalties to students who violate rules, sneak into sessions etc. Academic violations can result in less chance at getting your 1st choice.
• It should be flexible. Sessions may have to be changed or many not fully finalize until a week before the session.
• It is nice to handle quirks, like duplicated sessions a student takes only once, but where the student might have preferences for one of the instances over another. There may also be pre-requisites, so only students who take one session can have the sequel.
• Things change and manual tweaking can be advised.

Rank sessions in order, 1st come, 1st served

This was used in the prior year. Much like a traditional sign-up sheet in some ways, students could indicate their choices in order. If more students had a session as 1st choice than would fit, the ones who filled out their form first got in. This gave priority over all 10 days and so it was changed to rotate each week to distribute who was first in line.