ShotSpotter requests to be held in contempt rather than disclose its methodology

Now part of that might be because of the defacto police strike in response to "defund the police", but the noise went on long enough and was heard in nearby wealthy cities enough that actually motivated police forces were pushing to fix the problem and yet shotspotter proved useless.

This leads to the allegation that shotspotter doesn't actually work at all and is just there so when a hothead young cop does something wrong without thinking the police department can, after the fact, get shotspotter to gin up some probable cause.

I really wanted to include references to the research I did, but I was laid off at short notice (ahem, fired) for unspecified reasons, but it might have had to do with not introducing myself with pronouns. Not that I'm against it, I just felt that my freedom included the freedom to not use them. I was let go on a dime and didn't get to collect my research before I left.

But to briefly summarize how these systems specify their accuracy, it's usually with a range of angles. e.g. +/- 10 degrees horizontal, and +- 15 degrees vertical. I just did a quick google search to try to see if anyone has rolled up the various devices like I did, but nothing. However, here's one decent, non-paywalled paper that shows results under very ideal conditions:

http://nms.lcs.mit.edu/papers/ipsn07-girod.pdf

As far as my words: "no device on the market, nor algorithm could figure out that close of a pinpoint", not your words: "why it doesn't work," consider the accuracy in an empty field in the above paper, but then add in several factors, including: 1. reflections, particularly in a dense urban environment, can causing reverberation 2. humidity and temperature fluctuations, particularly as they vary vertically causing acoustic lensing effects. also temperature fluctuations affecting sensor differently from air. e.g. direct sun heating sensor. 3. extremely high dynamic range of the signal. 4. synchronization of detectors, 5. vandalism of detectors 6. accuracy of layout of detectors, 7. characterization of detector beam. 8. detector distance

This is not to say most of these can't be mitigated and improved, but they cost more money and time to work on all of them at the same time. The highly idealized results (open blank field) of a single shot in the above paper gave results +/- 8m in one direction and +/- 5m in the other direction with an average sensor distance of ~60m. So you're seeing about ~15% error in one direction and 6% in the other under ideal conditions and within a very short range. As sound propagates, the PV field evolves exponentially and it blurs and gets quieter and background noises interfere more.

Note that I mentioend the systems generally specify angles (polar coords), but i used rectilinear here bc I have a diff job and don't have the time to convert just for the sake of this convo, but that would be a step I wish I had time for.

If you want even more inside information from that side of the family, I will let you know that parallel construction with pseudo-private information is very real. This member, again trying to relate to me, brags about using social media to figure out many cases, hinting at having advanced access to e.g. facebook. I would go so far as to say that if you want to get away with crime, police will likely defer their attention to the low-hanging fruit of what they can solve with social media.

for those who asked for papers, here some that I vaguely recognize from my research. Most of these are paywalled, and I used my privileged access from a fancy school to get to them:

https://ieeexplore.ieee.org/abstract/document/5680318

https://tj.uettaxila.edu.pk/index.php/technical-journal/arti...

https://ieeexplore.ieee.org/abstract/document/8635092

https://www.spiedigitallibrary.org/conference-proceedings-of...

https://link.springer.com/chapter/10.1007/978-81-322-1823-4_...

https://ieeexplore.ieee.org/abstract/document/6637700

https://ieeexplore.ieee.org/abstract/document/7098998

https://ieeexplore.ieee.org/document/8289452

> Be kind. Don't be snarky. Have curious conversation; don't cross-examine. Please don't fulminate. Please don't sneer, including at the rest of the community.

Expensive and low-yield for whom? For the officer who's been directed their by the robot, they're incentivized to do so; it makes them look like they're doing their jobs instead of doing nothing. What's built into the system to penalize them for inconveniencing / endangering a bunch of people with nothing to show for it?