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Comment I've been bitten by this (Score 1) 40

I make a local cache of debian packages on one of my VMs, using apt-mirror. From time to time one of the packages would fail its checksum - reloading it from the offsite source would usually work. When I changed the VM's ethernet device to a virtual e1000, the problems went away. I later found an interesting cabling issue that was causing transmission errors between a switch the the physical host.

Comment Watching what flies in & out of your capital. (Score 4, Interesting) 88

I can seen the airport of my nation's capital from my balcony. I have a similar setup logging the position reports to a PostGIS DB, which allows some interesting queries ("Give me all the position reports found beneath a certain altitude within a certain polygon that describes a runway, sorted by airframe and timestamp") which allows you to determine what planes landed and took off.

Looking up who owns the aircraft can be done online, and it's funny when something owned by a holding company in the Caymans flies in. Now if only there was an online API that allowed one to query the visitors list for the legislative bodies, one could tie the data together, along with the record of votes cast, and jump to some intriguing conclusions.

Comment BRIN index looks useful. (Score 2) 104

I'm logging around 500,000 position reports for aircraft each day, which are naturally ordered by time (I also index on the ICAO24 airframe number). A lot of the queries I do involve the timestamps, which of course are only moving in one direction during the course of the day.

Comment I've seen this happen (Score 1) 96

I log ADS-B traffic to a PostGIS DB, and as part of the deduplication and data cleaning process, I look at the position reports, time & distance between them and the logged speed to see if they make sense. I sometimes have to add a fudge factor of up to 50km. ADS-B packets can get corrupted in ways that dump1090 can't fix up or detect, and I thought that the errors were due to that. Dump1090 has its own quirks when you're pulling position reports down from its JSON interface, but it's easier than pulling the ADS-B messages directly from its other interfaces and attempting to reconstruct the plane's track from that.

Comment Love the GIS Extensions for PostGRES (Score 1) 244

A former employer uses PostGIS extensively. It's more sophisticated than the support offered in MySQL (which only uses planar geometry) and is pretty much the standard in the GIS world. I'm writing an app which logs ADS-B position reports from planes, and it makes it trivial to detect when aircraft are landing or taking off from an airport - you can query if a point's within a polygon, and depending on speed, rate of ascent/descent and altitude, can come to some conclusions.

Comment Just like aircraft & ADS-B (Score 1) 25

Large commercial aircraft have to have a transponder that transmits (among other things) their height, bearing, speed and position. Each one has a unique identifier (ICAO24 hex code). All aircraft will be required to be equipped with these things after 2020. You can track them with a home mode aerial, a Raspberry Pi & a DVB-T dongle, using SDR. It's all broadcast in the clear (it has to be - the logistics of making sure everyone has keys for decryption would be a nightmare).

Comment Re: Thanks, assholes (Score 1) 573

The guns/suicide link comes from studies from Harvard (http://www.hsph.harvard.edu/news/magazine/guns-and-suicide/), The University of Southern California (as linked before) and the New England Journal of Medicine (http://www.nejm.org/doi/full/10.1056/NEJMp0805923). So you might want to reconsider your views on it. The Japan thing is a separate country with a very different culture, so a red herring. The above suicide studies are all within the US, so culture factors are already controlled for.

Given the wide variance of crime rates within the US, I would suggest that the states with higher murder rates implemented tougher gun laws as a response to high murder rates. The leakage of guns from adjacent states with lax laws would hamper those law's effectiveness. In order for it to work, the laws would have to be country wide, but I don't see that happening.

I'm quite happy for you to live your life as you wish, providing you don't go about gratuitously harming others. I just don't want a cultural meme, which has shown itself to be problematic, to say the least, to be exported to my country.

Comment Re: Thanks, assholes (Score 1) 573

Australia banned lead in gasoline in the early 80s (I remember it happening).

Lead poisoning leads to poor impulse control, aggression etc, all of which are implicated in murder, assault, robbery and other crimes. If you look closely at the crime stats for Australia in those previous replies, you'll see that the homicide rate did indeed drop, but other crimes, such as robberies etc, including armed robberies, not so much. Indeed they stayed fairly constant, and in some cases even rose.

So you could argue that it's a combination of a couple of factors - less brain damaged people and reduced availability of tools to commit murder.

In the US, the proportion of households with guns has been steadily dropping (http://rt.com/usa/gun-ownership-decline-us-111/) so a similar mix of causes would be in effect there.

And as mentioned before, you're 3 times as likely to commit suicide and twice as likely to be murdered if you have a gun in the house. More & more people are wising up to that fact, and that's why the proportion of households with guns is dropping.

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