The Grammar of Graphics

March 8th, 2016

R’s ggplot2 has the most elegant graph API that I know. This article by Hadley Wickham himself is a great introduction to some of the ideas underlying The Grammar of Graphics that he implemented. I think it contains a lot of great ideas for API design.

Passive investing is cheap, but not free

March 5th, 2016

Excellent article by Matt Levine

Passive investing is a way to make different fund managers compete with each other by forcing them to offer the same product. That competition lowers management fees for the customer. Unfortunately, the predictability of passive funds also makes them targets for other players in the market.

On one hand you have actively managed funds that are opaque and difficult for the consumer to monitor, and that charge high management fees which have to be balanced against their difficult-to-monitor performance. On the other hand, you have a low management fee passive fund which loses money to other market participants in an open market.

Seen this way, passive funds are still a better deal for consumers because it’s difficult to imagine anyone making an outsized profit without facing competition and having those profits be competed away / shared with the consumer.

NetSurveillance Web RTSP URL

February 27th, 2016

Spent way too long discovering this.


Was the 2015-2016 flu vaccine spot-on?

February 18th, 2016

The 2015-2016 trivalent flu vaccine protected against:

  • an A/California/7/2009 (H1N1)pdm09-like virus
  • an A/Switzerland/9715293/2013 (H3N2)-like virus
  • a B/Phuket/3073/2013-like virus. (This is a B/Yamagata lineage virus)

According to the latest Flu Express publication from the Taiwan CDC, the prevalent flus so far this season are:

  • A H1N1 (36.8%)
  • A H3N2 (63.2%)
  • B (25.2%)

Does this mean they got it completely right this year (for Taiwan at least)?

Do Critical Topics always bring Abrasive Conversations?

December 18th, 2015

The first rule of Improvisional Comedy the Yes, And rule, compels one to

accept what the other person has created (“Yes”) and then add something to it (“And”)

This is something that a skilled conversationist is good at. It poses trouble for the discussion of critical analyses however, because such discussions involve acts of disagreement (“No” – the negation of something the other person said) and of refocusing the discussion are to reduce incidental and nonessential complexity.

Being able to disagree productively and reach consensus regarding topic definitions is difficult, and something I’ve only managed to achieve with a handful of people who are all much more emotionally mature than I am. That’s really mostly other people figuring that I care much more about the topic than they do, however, and hardly an ideal resolution to the issue.

Ideally, in the face of disagreement, you would simply go up one layer in the abstraction stack, agree on the approach, and then figure out the specific bit of disagreement. By social convention, you start with the premise that both parties are rational, after which the search for the mistaken logic (which will be clear when identified) or for the differing premise can commence.

Hardly ever happens that way. Usually there’s too much ego involved, and enough entanglement with social status happens that it’s difficult to talk about the topic in isolation.

Where does Taiwanese air pollution come from?

December 16th, 2015

Conclusion: The pollution now (December) is from China, the pollution in November was locally generated.

Earlier this year, there was a bout of posts about whether the air pollution in Taiwan came from China. The air is apparently pretty bad right now, and this time I think it’s clear that it’s from China. I just pulled this screenshot from


Screen Shot 2015-12-16 at 2.02.24 PM

Observe that the pollution in Yilan Country, southeast of Taipei, is not that different from Taipei itself. This is what you would expect if the pollution came from far away. Compare this to the map from November (



Notice the huge disparity in homogeneity. Also, if I remember correctly, back then the wind was also unusually still. I think based on these facts, I would conclude that the pollution in November was locally generated and the pollution now is from a far away source, probably China. (Disregard the low pollution directly to the West, the wind doesn’t come from there. Also, there could be a time lag, so even the pollution levels in the direction of the wind source at the same point in time are not immediately relevant.)

If I had all the historical data in a csv, could probably do a better analysis than two snapshots, if anyone could point me to a source I’d be happy to do that.

What parts of Deep Learning are modern?

December 14th, 2015

Conclusion: outside of a very brief period in which pre-training with Unsupervised Learning was shown to be helpful, Deep Learning has largely been about hardware brute force, and learning how to use brute force to solve problems.

Terms I need to learn more about

  • Pattern Deformations

  • Hessian-free learning

  • Batch Normalisation (Thanks A Breitman)

  • Competing Units

Read the rest of this entry »

Deep Learning with Small Data

December 12th, 2015

I looked into the topic a bit more, and found this exchange, which I think makes sense to me.

The essence of the argument is that because Google etc. have a lot of data, they develop techniques that can make use of that data. However, if you do not have a lot of data, there are other, maybe less developed, techniques to use.

Neal Stephenson on The Problem with Personalised News Feeds

November 3rd, 2015

From The Diamond Age:

That the highest levels of the society received news written with ink on paper said much about the steps New Atlantis had taken to distinguish itself from other phyles.

Now nanotechnology had made nearly anything possible, and so the cultural role in deciding what should be done with it had become far more important than imagining what could be done with it. One of the insights of the Victorian Revival was that it was not necessarily a good thing for everyone to read a completely different newspaper in the morning; so the higher one rose in the society, the more similar one’s Times became to one’s peers’.

News has an important social function, and it’s often more important to read the same news as your peers than it is to read the news that is the most interesting to you.

Movies – Inside Out, The Little Prince

October 31st, 2015

Inside Out was amazing because it didn’t have a villain. In contrast, The Little Prince portrays all “normal” adults as villains. I never noticed this when I read the book years ago. Youthful angst is a frustration with being forced to obey rules that one can’t understand. Prince proposes resolving that dissonance by looking inward, and denigrates the customs of others as senseless and not worth interacting with. Contrast this French approach with the Japanese one in here.