https://ofdollarsanddata.com/how-to-invest-a-lump-sum/, posted 22 Feb by peter in finance math
In a paper from 2012, Vanguard found that 66% of the time it is better to invest your money right away (“Lump Sum”) rather than buying in over 12 months (“DCA”). I don’t disagree with Vanguard’s results (my results were strikingly similar), but I don’t think they went deep enough in explaining why this is true.
The main reason Lump Sum outperforms DCA is because most markets generally rise over time. Because of this positive long-term trend, DCA typically buys at higher average prices than Lump Sum. Additionally, in those rare instances where DCA does outperforms Lump Sum (i.e. in falling markets), it is difficult to stick to DCA. So the times where DCA has the largest advantage are also the times where it can be the hardest for investors to stick to their plan.
Yet today, the US continues to hold overseas territory. Besides Guam, American Samoa, the Northern Mariana Islands, Puerto Rico, the US Virgin Islands and a handful of minor outlying islands, the US maintains roughly 800 overseas military bases around the world.
None of this, however – not the large colonies, small islands, or military bases – has made much of a dent on the mainland mind. One of the truly distinctive features of the US’s empire is how persistently ignored it has been. This is, it is worth emphasising, unique. The British weren’t confused as to whether there was a British empire. They had a holiday, Empire Day, to celebrate it. France didn’t forget that Algeria was French. It is only the US that has suffered from chronic confusion about its own borders.
https://www.nytimes.com/2019/02/02/opinion/sunday/children-bored.html, posted 3 Feb by peter in cognition education opinion parenting
It’s especially important that kids get bored — and be allowed to stay bored — when they’re young. That it not be considered “a problem” to be avoided or eradicated by the higher-ups, but instead something kids grapple with on their own.
We’ve stopped training children to do this. Rather than teach them to absorb material that is slower, duller and decidedly two-dimensional, like a lot of worthwhile information is, schools cave in to what they say children expect: fun. Teachers spend more time concocting ways to “engage” students through visuals and “interactive learning” (read: screens, games) tailored to their Candy Crushed attention spans. Kids won’t listen to long lectures, goes the argument, so it’s on us to serve up learning in easier-to-swallow portions.
posted 31 Jan by peter
Top10VPN, for example, recently took a closer look at 150 VPN apps being offered in the Android marketplace and found that 90% of them violated consumer privacy in some fashion, either by the inclusion of DNS leaks, a failure to adequately secure and store user data, or by embedding malware:
"Simon Migliano, the head of this research, reports that at over 38 VPN apps tested positive for DNS leaks, exposing private data to hundreds of insecure links. Also, over 27 VPN apps were flagged as potential sources of malware when tested by VirusTotal.
Apart from this, the research also found intrusive permissions in over 99 apps. These permissions included user location, device information, use of the microphone, camera access and more."
https://www.nytimes.com/2019/01/17/arts/music/stradivarius-sound-bank-recording-cremona.html, posted 19 Jan by peter in art audio history music
On Jan. 7, the police cordoned off the streets. The auditorium’s ventilation and elevators were turned off. Every light bulb in the concert hall was unscrewed to eliminate a faint buzzing sound.
Upstairs in the museum, Mr. Cacciatori put on a pair of velvet gloves and took a 1615 Amati viola from its glass display case. He inspected it thoroughly, and then a security guard escorted him and the instrument down two flight of stairs to the auditorium.
The curator handed the instrument to Wim Janssen, a Dutch viola player, who walked to the center of the stage.
So what most likely happened is that we have scientists describing the progression of climate change. They give the uncertainty range and the press decides to only mention the lower boundary of this range. Then they somehow turn it into a deadline, put this in many headlines and never tell their readers where the number comes from. This made #12years a somewhat viral political meme. Chinese whispers of the worst kind. Journalists please listen to Peter Hadfield: check the source.
posted 31 Dec by peter
This article explains Reed-Solomon erasure codes and the problems they solve in gory detail, with the aim of providing enough background to understand how the PAR1 and PAR2 file formats work, the details of which will be covered in future articles.
I’m assuming that the reader is familiar with programming, but has not had much exposure to coding theory or linear algebra. Thus, I’ll review the basics and treat the results we need as a “black box”, stating them and moving on. However, I’ll give self-contained proofs of those results in a companion article.
So let’s start with the problem we’re trying to solve! Let’s say you have n files of roughly the same size, and you want to guard against m of them being lost or corrupted. To do so, you generate m parity files ahead of time, and if in the future you lose up to m of the data files, you can use an equal number of parity files to recover the lost data files.
posted 16 Dec by peter