Ask HN: What interesting problems are you working on?

I'm pulling in trips (when does an agent leave, where do they depart from and go to, what mode of transport do they use) from https://www.psrc.org/activity-based-travel-model-soundcast, which is a very fancy model that uses land use, census, vehicle counts, etc. This is the most realistic data that's public, from what I've found.

Map data comes from OpenStreetMap. Aside from the problems I mentioned with inferring good geometry for some intersections, it's pretty solid.

Drivers in A/B Street have to find parking, and walk between buildings to parked cars. So the amount of on- and off-street parking in an area is pretty important; there might be lots of congestion in the sim if I don't know about parking. I'm inferring on-street from http://data-seattlecitygis.opendata.arcgis.com/datasets/bloc..., which is extremely inaccurate, and I have no data source yet for private parking attached to individual buildings.

Until I have some of this data, calibrating the sim against reality is pretty tough.

I've been working on a video editor (https://phot-awe.com), for more than 1.5 years.

Biggest challenge has been speed: first proof of concept was a prototype that was kinda' slow (C#/WPF/Windows). I've re-written it using the lowest level possible stuf from WPF, and that took me a looot (roughly 3-4 months, to also make it easy to extend/modify). That was an improvement of roughtly 3-4 times, but for non-trivial stuff, it was too slow (and especially saving the final video was insaaaanely slow). So, I did another rewrite in UWP, and this took another 4+ months.

Now, I'm really happy about the speed - it's 3-4 times faster than before, and at saving, it's 10-12 times faster.

In order to make it happen, I've worked insane hours (and still am) - but that's that. Right now (the following 2 months) I'm focusing on stability and some improvements. Hope to have apretty cool new feature ready in roughly 3-4 months, and we'll see.

Challenges: countless, probably I could write a book ;)

1. Parsing existing videos - in WPF that was insanely hard, and it took me a lot of time to come up with a viable solution (which when porting to UWP, I ended up throwing away)

2. Estimates - I was pretty good at estimating how long a task would take. But due to the fact that everything was new to me (basically, animating using low level APIs was close to undocumented), so pretty much everything took 4-5 times more than I expected. This was soooo exhausting and depressing, since at some point I just stopped estimating, because I knew it would take me longer.

3. Changing the UI due to user feedback - basically, I ended up redesigning 80% of the UI to make it easier to use. What I thought would take me 1 week, ended up taking me 1+ months.

4. Tackleing everything at once: trying to implement a new feature, while dealing with bugs people would find or dealing with issues that would come up when trying to implement the feature. And dealing with issues that came up from the photographers I collaborate with (those that create the app's effects/transitions).

5. Porting to a new technology (UWP/WinRT). This is something that I hope I never have to do again - I was forced to do it, because of the speed gains. I had to reimplement / retest every control I initially developed - that's one thing. The other one is dealing with the idiocracy of WinRT - which loves async stuff / and also loves limitations. Also, the UWP documentation is soooo bad compared to WPF - and there are very few resources, because most people are put off by it (not going to go into detail as to why, that's another book I could write). Not for the faint of hearted. 6. Compilation times - on the old technology (WPF), everything was insanely awesome. On UWP, compilation times are roughly 6 times slower. That is baaaaaaaaad. I'm doing all sorts of workarounds to make things faster.

I'm working on an automation app https://github.com/rmpr/atbswp to make automation accessible to non technical people. I used something like that called tinytask back in time on windows (mostly to play automatically my Asphalt 8 airborne races :p) but when I switched to linux I noticed that nothing like that exist, so this is aimed to address that. Right now the practical use I saw is for automating live demos during conferences for example.

I like this as a single aggregate measurement to base scores on. Some of the difficulty comes from displaying this score as the simulation runs through the day. At first the average might look great (a change helps the bus in the early AM), but then rush hour hits, and the change actually makes things worse. Or maybe a re-timed traffic signal helps buses going northbound in one spot, but hurts the southbound buses, so also seeing the change between each pair of stops is important. https://imgur.com/Fk1GfKG is what I've got for this so far, but I think a different way to visualize this is necessary. :)

> I also think supply of nuclear fuel can be an issue, although there are some concepts for other types than uranium.

There are 3 fission fuels occurring in nature: Th232, U235, U238

Actually, our reserves of Uranium are greater (by energy available to generate) than all of our Coal, Oil and Natural Gas reserves combined.

Our Thorium reserves are even greater than those.

In fact, Thorium is extracted as a byproduct of Rare Earth Metal extraction, and so we currently mine enough Th232 per year to replace the entire global energy and fuel industry even though there is no demand for Th232 extraction. Kind of mind blowing.

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> [fission] it is expensive in deployment

I don't see where this idea comes from - in real life, regions which are powered by more fission have significantly cheaper electricity than those who are powered by less.

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> the problem with nuclear waste

I genuinely don't think there is a problem with nuclear waste, and that this concern is a myth / misunderstanding based on a mix of fear-mongering via conflation with nuclear weapons and a lack of comparison.

Consider the following: all energy sources have waste products - nothing is 100% efficient.

Fossil fuels pump literally billions of tonnes of toxic gas into the air as their waste product. It moves around, we can't store it, and it is responsible for the deaths of millions of people each year through air pollution.

Renewables production has the same issue (although different gases), and also tends to pollute the water and local environment with other toxic chemicals and metals.

Nuclear fission produces the most dense, least amount of waste of any source, which is solid and easy to manage. We know where quite literally all of it is, and it doesn't hurt anybody or negatively affect the environment in any way as long as you keep it store somewhere.

As far as I'm concerned, nuclear energy does not have a waste problem, it has a waste solution. Global warming is the problem with energy waste, more specifically it is the problem with hydrocarbon waste.

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> Another example is Norway that uses 98% hydro power. Sure, they have topological advantages not available everywhere. But technologies like this could open up more possibilities.

Agree with you. Renewables tend to vary in effectiveness based on location - in those locations which are well-suited for them, I think they should be used! Though I'm not sure what you mean by "could open up more possibilities" - we've had hydro power for thousands of years.

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> I doubt that Germany closing plants was a terrible decision.

Note the following excerpt from Mike Shellenberger on Twitter:

  Germany’s renewables experiment is over. 

  By 2025 it will have spent $580B to make
  electricity nearly 2x more expensive & 10x
  more carbon-intensive than France’s. 

  The reason renewables can’t power modern
  civilization is because they were never
  meant to.

  A major new study of Germany's nuclear
  phase-out finds

  - it imposes "an annual cost of
    roughly $12B/year"

  - "over 70% of the cost is from the 1,100
    excess deaths/year from air pollution
    from coal plants operating in place of
    the shutdown nuclear plants"