629 karma · joined July 4, 2017
What I think should be there is a daemon doing autocommity and automatic sync with server. Even if you work from multiple machines.
Probably the biggest issue with INSs is accuracy of the raw IMU measurements. The acceleration must be integrated twice. That means any error in the measurement gets exponentially larger with time. Rotation velocity measurements are integrated only once (some IMUs measure absolute orientation but it is not the case here) so the error does not explode as fast. Is is the combination with translation that is problematic. If you rotate around vertical axis by 90deg +/- 1% and then travel for 1000km +/- 1% the rotation accuracy will cause bigger error in final location.
To have an INS capable of long time operation without any other means of drift correction one has to nail many other things.
- Gravitational constant varies and you have to have an accurate map of it. We might not have a good enough one. I don't know. The subs could collect their measurements and perform a large scale optimization to increase the accuracy of this map.
- The rotation of earth gets added to the rotation speed measurements. The rotation is not constant (hence the leap seconds from now and then). We have to be able to extrapolate it well enough.
- Sampling rate of the quantum IMU has to be high enough. How usefull is the most precise measurement if you can measure only once in 10 minutes? Traditional IMUs sample at 1 kHz and more.
- Does the new quantum gyroscope add enough value to the accuracy of the final IMU compared to Fibre-optic gyroscopes? They are incredibly accurate as they are based on laser interferometry and then can sample at high frequency. Plus they are an established technology which partially benefits from economy of scale [5] because they are used in airplanes [6].
- The measurements of both rotation velocity and acceleration have to be measured in 3 axes. Are the relative orientations and translations of those axes stable enough as the device moves?
- Is the noise present in the measurements corelated to something or is it truly random? The corelation could mean an systematic error to the state estimate.
- You will likely also have to have an atomic clock on board labeling each IMU measurement as soon as it is made. But this is not a problem nowadays as one can have a small Rubidium-based atomic clock in a package starting to resemble a chip [2] [3] [4].
- And of course you will need enough computing power to calculate everything. I'm not sure how modern hardware they are allowed on board of nuclear-carrying subs. This is slight problem for things like Mars rover as due to the testing requirements the main chip can be easily 30 years old when the rocket is launched [7].
Also, the situation is not as bad as we can utilize the sensor fusion and correct lots of errors caused by IMU measurements. From the top of my head one can obviously measure water pressure which estimates depth (with some error). Sea bed topology could be other type of measurement but my guess is that this measurement is too crude compared to the accuracy of the quantum-based INS.
[1] https://www.imperial.ac.uk/centre-for-cold-matter/research/q...
[2] https://eu.mouser.com/new/microchip/microchip-macsa5x-atomic...
[3] https://www.sparkfun.com/products/14830
[4] https://www.accubeat.com/nano-atomic-clock
[5] https://emcore.com/wp-content/uploads/2016/12/EMCORE-Commerc...
[6] https://www.airbus.com/en/products-services/space/equipment/...
[7] https://bigthink.com/hard-science/perseverance-rover-brain/
One scenario is when your goal is to make something new. Something, that would feel different and have different ergonomics. This is like inventing a Python when there are mostly C-style and Pascal-style languages.
Other is when you are interested in a particular behaviour of the language. Like type system. Why should you bother whether you write let x = 5; or int x = 5; when all you are interested in is its type. This is likely the case of this paper.
Then Haskell came. They presented a nice language based on something others were familiar with (lambda calculus). Since then, two interesting things happened as I understand it. Poeple started adding more nuanced optimization to lambda claculus based backend. This is similar to what LLVM does. Second thing is that instead of comming up with their own languages, most adopted Haskell-style syntax. Just look at modern of functional languages. The mostly look like Haskell (well, ML).
Why not to start from what people already know and love and bolt your experiments on top of that? What I do with my DSL AmpLang is to start with Python, throw away parts I don’t like and add the things I’m interested in. It seems to work well enough and my language feels familiar for Python developers. I did not test that but many of existing Python programs would work out of the box in AmpLang. Python grammar is very simple. Even more so for 3.9 which does not have pattern matching.
What I want to say is that I don't like this practice either but should we cancel businesses just because we don't like them? They are not stealing or anything. I'd say they are in a light grey business but for sure not black.
And I guess there is a bright side to this all too. At least for large-ish businesses. If nissan.com was owned by domain squatter then they would sell it to Nisan for 1M or something and both sides would be happy.
That being said I think from my personal experience that there is a bigger problem with the service. I got a very bad experience from a relatively new all-5-star host. The host lied to us and AirBnB, tried to get more than $1000 for various claims and so on. At the end AirBnB did a very poor job at mediating the claim. Then I wrote a review. I tried to be as objective as possible. AirBnB simply deleted the review. They didn't ask us to correct anything or anything. They straight out deleted it.
I believe that by doing so AirBnB is misleading both guests and their investors. This creates an impression that the service is better than it actually is. That is likely inflating their stock price. I personally believe that there should be a class action lawsuit or Hindenburg research paper about this for them to do anything about this.
If the app would scale a lot I would still need to go into all that trouble but at this early stage the benefits of really simple infrastructure is immense.
[1] https://www.reddit.com/r/UsbCHardware/comments/z2hncm/recent...
My take aways are: 1/ You can do RE without knowledge of assembler (which I know nothing about) 2/ C decompiler is useful and you will need to learn some patterns of how things get disassembled 3/ There are many good videos on youtube on how to get started 4/ There is a debugger to see what the program actually does but I never managed to get it running. That would be awesome feature to use.
Likely problem is with industries that are more difficult to electrify. Like aviation.
Having commercially viable e-Fuels would have a few advantages. You can keep your old car and be net-zero, sport cars would be a thing, you can decarbonize other types of transport which are more complicated to decarbonize than personal vehicles. Like maritime, airplanes, long haul tracking and so on. Its like killing many many birds with one stone.
At the momeny, the fact that ICE cars would be banned could be a red flag for new projects trying to push for e-Fuels as it limits their customer base. This is important because at the beginning they will be more expensive that crude-based products so you need to find a niche market where poeple are willing to pay premium for net-zero. I think that companies like Google, Apple and so on would be willing to pay maybe even 2x or 3x for the fuel if it guarantees true net zero (no offsets).
As for the efficiency. It is true that the e-Fuel based chain would be less efficient than all-electric but there is a way around it. Efficiency is mostly important to keep the costs low. If you need 1kWh on the output and the efficiency is 20% instead of 90%, you will need 5 kWh instead of 1.11 kWh on the input. But what if the input is next to free? Two ways of getting that. One is by having a surplus electricity which we will have a lot as we inevitably have much more installed capacity in solar than peak load. The other one is to build renewables where they work very well (like Mauritania for solar), produce e-Fuels on-site and than ship them globally. Economy of scale will allow you to decrease cost of e-Fuels dramatically.
It might seem like a long shot for you at the moment but I gave it a lot of thought and discussions and research and I think that this very realistic and very likely scenario.
PS: If you want to start a business in this area, let me know. I'd be very interested!
The answer depends on what kind of CV you're looking for. As for the old-fashioned CV I think that visual odometry, bundle adjustment and dense reconstruction are great things to play with and they have practical applications.
One hard-ish problem I used to work at is city-scale 3D reconstruction from photos. You can have street-level image data you collected to get the high detail and some aerial pictures to get the consistency for wide-area. A problem of matching street-level and aerial pictures is even interesting from research point of view (keyword is wide baseline image matching). With this you can build something similar to what Google Map has where you point your phone on the street and you get overlay directions. And if you call it mixed-reality metaverse, you can start a startup 6 months ago.
As for the NN-based I'll leave that for others.
I have already tried you.com but honestly the results were underwhelming. The suggestions of the results page were not very good. I was trying that while doing some Python. I guess other languages might be even worse.