gh02t
gh02t on Hacker News
Denon actually tend to play nicely with local control, with telnet, RS-232 serial, and local network APIs that are easy to use. My Denon receiver worked OOTB with Home Assistant.
This is also a problem in classical HPC, there aren't very many algorithms that can scale linearly with cores. That's partially why so many HPC algorithms tend to be built on matrix multiplication and Monte Carlo, because those do tend to scale near arbitrarily.
You were one generation before me, I started college in 2007. By then it was all those super cheap little 4 port Netgear switches most people reading this have probably owned at some point. I don't remember us having official dorm wifi but we were allowed to have our own wireless routers, probably an IT nightmare by today's standards. I recall we also all got publicly routable IP4s.
Hubs were still just barely still relevant when I first started learning networking, but it was late enough that I don't think I've ever encountered one in serious use. Especially after port mirroring became a common feature even on affordable switches. I think we had an old pile of industrial/scientific test equipment in grad school nobody wanted to touch that was using an old Cisco hub, but my memory is fuzzy.
I've definitely never seen any old Thicknet networks in use, though I have seen Token Ring in active use semi-recently. I never learned anything about Token Ring other than I remember old CompTIA mentioning it existed.
I do have a fondness for seeing this old tech that was way out of my reach or just barely too old to encounter back in the day being used, it's so neat to learn about. ClabRetro on YouTube is one of my few "drop everything and watch a new video" creators.
People may forget that Ethernet originally had a shared transmission medium and collisions were a serious limitation. Switching was a later addition that mostly solved collisions and really paved the way for Ethernet as we know it today.
GL.iNet is more open (they run an OpenWRT fork that they open source with a proprietary GUI on top). They have a beta for a mesh system on top of that:
https://www.gl-inet.com/en-us/pages/mesh . I haven't tried the mesh, but I have had very good experiences with a few of their routers and they are what I recommend to friends.
Ubiquiti mesh stuff works very well and is an overall polished experience. Supposedly their APs are at least distantly descended from OpenWRT but they are not open source. Their platform is pretty open in terms of integrating with other stuff and not locking you in, at least.
See ntopng, it provides a nice monitoring UI for exactly this type of scenario. It's higher level than Wireshark, more focused on high level traffic analysis.
I have a Studio 2 for work and even on windows it runs like absolute garbage. Almost unbelievably slow at everything and locks up frequently. Maybe I have a dud with some sort subtle hardware fault but it's by far the worst computer I've owned. Not a good look for a premium priced laptop that is supposed to be a showcase for Microsoft.
And yeah, can't run Linux on it either to try and salvage it because of all the weird and undocumented hardware.
SELinux was originally designed by the NSA to serve their needs, which are probably a bit more intense than "normal" users, and that was over 25 years ago. I'm not convinced a fresh effort couldn't do better, though I'm more skeptical that anyone is willing to invest the resources.
They do use the official client, but it also makes it fairly easy to bridge tailscale networks with regular wireguard clients with normal routing rules.
PfSense and OPNsense both support Tailscale and can integrate it with their normal routing/firewall behavior. I think OpenWRT can as well but I haven't tried it.
The prospect of going to a website I've never visited before, getting a captcha, and it saying "we don't think those are YOUR feet, access denied" is a little TOO believable.
"We reserve the right to retain your security feet pics indefinitely, but won't use them
for advertising purposes. We may use them for other
business purposes, subject to change at any time without notification."
--new TOS
Then, a few months later x.ai announces a new SOTA frontier model, FeetGrok.
25 years is the standard time horizon for automatic declassification, and someone high up probably decided to collect things together to publicize in an attempt to score some political kudos.
Speakers can act as part of a useful microphone circuit but you're missing all the amplifiers and ADCs and other stuff to use it as one in any sane speaker driver circuit. They'd have to intentionally add all that, which maybe they would, but it'd be easier to just stick a tiny $0.05 all in one microphone chip on there.
Yeah I think I explained it badly. They sorta stream through the detector until they interact, and then potentially undergo multiple compton scatters or photoelectric absorption (or other weird stuff) that produce secondary particles that actually excite a region around the discrete interactions and those excited atoms are what produces the observable signal. Then (at least for a scintillator) the atoms that got excited relax and release a flash of light with a characteristic decay time that is the main limit on how precisely you can resolve individual gammas. Semiconductors are kinda similar but dislodging electron-hole pairs; the higher mobility of these pairs is why the resolution is so much tighter. Imaging detectors have more electronics attached, e.g. two photomultipliers at each end or pixellated photomultipliers, and timing analysis of these pulses is how you get position. Things like a full energy deposition peaks happen when the gamma ray dies in the detector, but it doesn't necessarily dump its energy all in one spot. Since you have to wait for all the excited atoms to decay or the total charge from electron-hole pairs to be collected you have to integrate the total amount of light/charge over some window to get the total energy deposited. Sometimes they escape out the other side and take some of their remaining energy with them, which causes some distinct features in the spectrum too.
The timing and electronics for doing position sensing of the gamma path through the detector (i.e., what you need to reconstruct an image) are... complex. Dead time and false correlates (e.g. another gamma in the detector at the same time, aka false coincidences) are a thing and they are factors that contribute to uncertainties. There's a bunch of statistical analysis you have to do to try and correct for these effects and pull the signal out of the noise. In a Compton camera, you can correlate the first scatter's trajectory back into a cone of possible incident directions, which you then stack up to form a picture. Hence why I said the image you get out is very blobby and more like a heat map than an image. But you pay a price in efficiency, as you can only count some fraction of the actual interactions in the detector now. I'm a bit rusty on the really nuts and bolts details, I don't work with this type of detector anymore. We mostly try to avoid using this type of detector for our localization, because they are crazy expensive and complex.
Spinning shield is a thought people have had but it doesn't work very well in practice (for gamma imaging). Usually you want to avoid anything that blocks gammas as much as possible because you need every one you can get. I wanted to try spinning one of the scintillator logs we used, which is more or less the same idea, but it isn't practical either for a bunch of reasons.
Gammas tend to act more like particles in the detector. They don't stop all at once, they tend interact multiple times and deposit their energy in multiple places along a line via a ton of different physical interactions. My description was simplifying and conflating things a bit, you can look up optically segmented detectors, as well as Compton scatter cameras if you want a better answer. There are other imaging approaches, too.
It was probably an imaging radiation detector regardless, the spinny bit would likely be some sort of camera to add context to the radiation image.
Imaging detectors can get a lot fancier than just two planes. One design is basically segmented crystals and you look at the timing between the separate segments light up as a gamma ray passes through each quadrant. You can then work backwards from those sub nanosecond time difference to get the direction, and stack up a bunch of events to make a sort of picture (more like a blobby heat map).
For neutrons there is an even crazier imaging technique called a coded aperture that I won't even try to describe here. Suffice to say it's very clever and unintuitive.
The cheapest worthwhile detectors out there are the Radiacode ones. They are excellent for what they are, but they run around $300. Cheaper Geiger counters are unfortunately kinda useless, at least for this.
Unfortunately smart phone cameras kinda suck performance wise. Radiation detectors fundamentally need some mass to actually absorb and detect radiation, so while cameras are basically similar to semiconductor radiation detectors the performance is so bad as to be useless. I haven't really ever seen the camera detectors be used for anything useful.
Radiacode detectors are about the only affordable detector with actually useful performance out there, and they are around $300. Which is also drastically cheaper than anything else out there, the next cheapest actually useful detector out there that I know of is 10x that price.
Not us, but probably an imaging radiation detector with LIDAR. Its another technology for search, with its own tradeoffs and advantages. We are friends with a couple companies that make that tech, but it's a different thread of R&D. Arguably a bit more mature; doing localization like we do with "normal" detectors on the ground is pretty challenging. We've done pretty realistic joint exercises with the military with our tech (called QkRad) but nobody has actually fielded it in a real emergency yet. We are around TRL 7 if you know that terminology.
These sort of loss events happen much more often than is reported widely. Not like something that happens every day, but there are a non negligible number of events every year. The Nuclear Threat Initiative catalogs publicly known events if you want to browse.
They are more prevalent than you think, especially in places like ports and airports. But part of the problem is they are typically
expensive for anything more sophisticated than a basic Geiger counter, like most commercial offerings start at $5k and can very quickly go into the hundreds of thousands or millions of dollars per unit. And they require a lot of training to use effectively.
At least in the US there is also a pretty substantial network of teams and equipment for providing radiological technical support in an emergency. Examples of this are DoE RAP and the USNG CST. Now part of the motivation for this work was that a lot of the techniques for actually doing a search are fairly primitive, but there is a major support network with most of the tools and skills ready to go 24/7. It tends to all be very low key and fly under the radar, mostly because even a hint of one of these teams being deployed tends to cause a panic.
Ha, that's me. Thanks for posting this. It's late where I am but I can answer questions. I took a brief break on this topic after I graduated and worked on other stuff, but the company I'm at now has done a lot of subsequent work on this, including making it practical in the field. Though as I mentioned in the prior thread, bridging the valley of death and selling it as a product is still a challenge.
Good luck. I'd wager that most methods to protect your privacy aren't nearly as effective as we think they are. While I don't think it means that you shouldn't try to protect your information, I typically assume that anything short of very extreme measures is only mildly effective.
> Newer linux folks like it because they're used to it, people who don't like it use devuan, gentoo, or one of the others that still lets one use openRC or whatever else.
This is a bad generalization. Counterpoint, I've been using Linux as a daily driver for like 25 years now (and have also used other Unixes/likes fairly extensively). I have my gripes with systemd, but I personally prefer to use it over OpenRC etc. I don't think I'm alone, either, as distros like Devuan are pretty far down on usage lists. There are plenty of Greybeards out there who dislike systemd enough to use something else, but I suspect there are at least as many out there who like it or don't care enough to use an alternative.
Companies like Red Hat/IBM operate in Illinois and for better or worse have controlling interests in Linux and across open source projects pretty broadly. Wouldn't they be forced to include the capability in their products, which then percolate out to everyone just by network effects?
Actually, someone walking around with a detector and us localizing in real time is what the current state is. There's been a lot of development since this dissertation to let it run in real time, and to integrate with tactical radiation detectors that the military/police/civil defense teams tend to use. Unfortunately that's mostly unpublished work at present.
This incident inspired my PhD dissertation on radiation source search. The techniques to search for sources like this are remarkably primitive, even today. My company works on this tech, but it's hard to get traction because the US government basically stopped investing in CBRN technology around when the Cold War ended, and hardly any other countries take it seriously as a threat.
Not that search techniques would have helped stop this incident, they basically didn't even know it was lost until the capsule was already broken and people were dying.
And they got that position of dominance more via shady deals and sketchy practices than by producing excellent software. Microsoft has done some good engineering, but that's not what made them what they are.