phugoid

Value(s): Building a Better World for All by Mark Carney, the current prime minister of Canada. He starts out with his perspective on the history of economics and money - it reads a bit like a textbook.

He has a knack for being critical and optimistic at the same time. Funny too!

Hardware-wise, the industry has moved from hydraulic to electric motion jacks. It's great if you can avoid pumping high pressure hydraulic fluid. You want to think about capacity to handle the mass you'll put on top. Also, number of degrees of freedom and dynamic response (can it give you twitchy movements, can it also give you large accelerations by massively tilting the platform).

You have a layer that translates the desired accelerations from a physics model (say at 60 Hz) into filtered motion jack length commands (say 400 Hz or more). You don't need massive compute, just keep the latency down and ensure a steady stream of commands to the jacks.

The experience you get from the simulator comes from multiple systems hitting your senses at the same time. You yank a joystick and expect to feel a motion cue and see something in the visual system. For flight sims used in pilot training, you need a response within 150 msec and you want the motion and visual to be in sync to avoid motion sickness.

A car simulator would be a lot more twitchy than passenger aircraft, 150 msec may be too slow.

This really made my day! I was a flight simulator engineer for 20 years and it brings back fond memories of a project I worked on.

Simulating the passenger cabin is important for crew evacuation trainers. Those are large, lifelike fuselage sections that you put on a hydraulic motion platform and run flight/crash/evac training scenarios.

To get a realistic out-the-window view, the trainers I worked on had a PC monitor behind each window opening. We used FlightGear in a master-slave setup: the master node simulates physics and feeds accelerations to the hydraulic platform, and the slave nodes generate out-the-window visuals for each window.

HN is a spark plug that caused various forward motions and explosions in my life.

I learned about open source and Linux; in time that went from a new hobby to a change of direction in my career.

I learned about startups, and figured I should try since I'm also a genius who can build a great product. It took quite a bit of money and time lost to convince me otherwise.

I found out about the online CS Masters program at Georgia Tech and did that a few years ago, this led to moving countries and getting a job doing AI.

Maybe we read different articles, but "Build an initial product" is what he said to do _after_ the hypothesis testing.

Even with a pretty good model, if you introduce new failures that were not anticipated/tested, there's a risk that the system will not behave as per the aircraft. Now you're giving "negative training" to your pilots, maybe worse than no training at all.

Also, imagine you're an airline with thousands of pilots and dozens of instructors: you're running an airline and a school at the same time. You need to build a curriculum of training and testing that will standardize your pilots. There's room for thinking outside the box but not too much.

> Do simulators have the same hardware as real planes, or do they have a software model of the airplane?

If you're looking at the highest fidelity level D simulators, the instruments and controls in the cockpit are either the same parts as the aircraft, or functionally identical (but cheaper).

> If you simulated a broken AoA sensor, would the simulated plane behave similar to the real plane? Would the MCAS system have the same bugs in the simulator as in the one in the real aircraft?

One of the big costs in building a simulator is buying the data package from the aircraft manufacturer, with the aero model and details of system internals, things like electrical and hydraulic schematics. Sim makers build a software model of these internals at a pretty low level. For the most part, if you introduce a fault in some part of the system it will behave the right way as an emerging property, not because you're forcing the system to have the right outputs.

Some software components from the aircraft get installed on the simulator with the same hardware platform from the aircraft, others get run as executables on the simulator's computers, and others get re-implemented from scratch (lots of FORTRAN and C).

That kind of detail comes into play when the instructors introduce multiple failures at the same time - pilots have to take corrective actions to make the faults go away or manage them - if you don't model the systems at a pretty low level you'll never high fidelity.

> Can you try new scenarios in a simulator, or can you just try scenarios that the simulator was designed to run?

There is a list of malfunctions available to the instructor, who runs the session from the back of the "cockpit" on touch panels. For the most part, these malfunctions cover failures that are anticipated by the aircraft manufacturers, and the corrective actions / system behavior are well understood. Each fault is tested to make sure it works properly. You don't go and fail some random component in the system.

When an important failure happens in the real aircraft, it might get added as a training scenario to simulators already in operation.

A good book can immerse you in someone else's way of thinking, in their world. I think the time it takes to read is an essential part of that process, in the same way that watching a two-hour movie can move you more than the 20 second preview that gives it all away.

For example, I ran across this gem recently:

"In the same way as people who've been to a concert carry about with them the melody and haunting quality of pieces they've just heard, interfering with their thinking and preventing them from concentrating on anything serious, so the talk of snobs and parasites sticks in our ears long after we've heard it. And it's far from easy to eradicate these haunting notes from the memory; they stay with us, lasting on and on, coming back to us every so often."

I would never connect those two ideas. It's beautiful. The writer is Seneca, a Roman who was born around the time of Christ. He was idealistic yet street-smart, lofty though sometimes petty, and very opinionated. I enjoyed walking a mile in his sandals.

The author seems very pleased to experience the power gradient of being surrounded by hungry students looking to join the club.

"You’ve got a lot of learning to do - minimum nine months - before you even get to working with me."

Such an unpleasant disposition. People who demand humility of others could use a bit of more of it.

Definitely not a degree mill. Have a look a their well-established OMSCS program, which offers an MSc in Computer Science. This is an offshoot of it.

Getting in to their OMSCS program is far from guaranteed - they have lots of older applicants and they evaluate each on its own merits.

Right now, I am taking the equivalent course to yours in an online CS masters program.

The best thing they've done is structure the entire course around building a web database app. They provide a real-world description of what's needed, and break it down into big chunks that are synchronized to the content of the course's three exams. This gives a clear over-arching goal to the class. For people who have never build web db apps, they will really feel like they've accomplished something by the end.

Probably an impossible-to-find asset. Such a collaborative effort is likely to attract the most vocal and opinionated people, many of whom do not have children of their own. I am simply extrapolating from the median author of the parenting books I've read (and thrown away afterwards).

You may find that successful parents who balance two or more kids with full-time jobs and some measure of sanity will not have the interest or energy to put into such a project. The more enlightened among them may also hold their tongues, having realized that what works for their kids is not universal.

If OP lives in a city, it shouldn't be hard to find a sharp college kid who will tutor.

I force myself to read a book about it, from cover to cover; then I start using it. That gives me a helicopter survey of what the language looks like and its main ideas.

Of course I forget all the details, that's what books are for. It does seems more effective than just trying to map what I know from other languages into the new one.