615 reputation
416
bio website dcook.org/work
location Tokyo, Japan
age
visits member for 2 years, 11 months
seen Sep 16 at 19:49

UPDATE: My new book, "Data Push Apps with HTML5 SSE" is out and selling! Get it from O'Reilly here: http://shop.oreilly.com/product/0636920030928.do Or from Amazon here: http://www.amazon.com/dp/1449371930 Or from any good bookseller.


I'm director at QQ Trends, a company that solves difficult data and software challenges for our clients. (We often have freelance projects, so get in touch if interested.)

UPDATE: currently looking for a part-time CSS/JS programmer. 理想は東京所在、日本語が読める方。Interesting project(s), you will definitely learn something.

(And, of course, please do get in touch if you have interesting challenges that you would like our world-class experts to work on!)

Typical work: doing fun stuff with data (fixing, mining, etc.), web sites (front and back-ends), trading strategies. Research: trading strategies, computer go, machine translation, understanding context, AI search algorithms. Languages: C++, PHP, R, javascript, and many more.

I'm British, living and working in Tokyo for almost 20 years. Human Languages: English, Japanese (fairly fluent, 1 kyu), some German, Chinese and Arabic.

(Contact me at dc at qqtrend dot com: please mention you are coming from StackOverflow, so I know it is not spam.)


Easy ways to irritate me on StackExchange sites (whether my own question or someone else's): 1. Downvote without a comment (N/A/ if someone already left a comment and you just agree with it, of course); 2. Answer in comments. Other than that I'm a really easy-going pragmatic guy :-)


Sep
4
comment ROC: difference between discrete and continuous?
Thanks, that is a very clear example.
Sep
4
comment ROC: difference between discrete and continuous?
BTW, re: PerformanceAnalytics, "most of the functions assume arithmetic returns". I now notice user508's comment at quant.stackexchange.com/a/1082/1587 says "PerformanceAnalytics defaults to log returns." :-(
Sep
4
comment ROC: difference between discrete and continuous?
Thanks Joshua. The article was also very useful in pointing out the terminology, which was where a lot of my confusion had come from! (discrete == simple == arithmetic) (continuous == log == geometric)
Sep
3
asked ROC: difference between discrete and continuous?
Aug
22
comment Is this a common variation of sharpe ratio?
Thanks; now I know what I'm looking for I see R also has functions for DownsideDeviation, SemiVariance, etc. I didn't ask in the other question as: a)it was off-topic; b) you'd already expressed your bias, and I wanted to hear arguments against ;-)
Aug
22
comment Drawdown calculation for strategies
@Freddy BTW, I started a question about your comment on Sharpe Ratio: quant.stackexchange.com/q/3986/1587
Aug
22
asked Is this a common variation of sharpe ratio?
Aug
15
revised portfolio optimisation with VaR (or CVaR) constraints
Added link to the book referenced
Aug
14
suggested suggested edit on portfolio optimisation with VaR (or CVaR) constraints
Aug
5
comment Why use a column database for tick/bar data?
@JL344 Re the "Row-oriented databases just aren't designed to handle a huge number of tables as effectively as a huge number of rows in one table." comment, it seems this is a good point. MySQL uses one file per table, so it should be fairly unlimited. However see (serverfault.com/q/83438/87322) where meta queries can become notably slow once you have thousands of tables, apparently. (This is a MySQL bug that is fixable, rather than a flaw with the row-oriented concept.)
Aug
5
comment Why use a column database for tick/bar data?
@JL344 One table per symbol of OHLCV data in a row-oriented DB is very different from the column-oriented DB. In the former they are are stored in row order; in the latter they are stored in column order. In the former appending a new row requires appending, say, 44 bytes, to a single file; in the later it requires appending 8-12 bytes to each of 5 separate disk files. That is their advantage; the gist of Q1 and Q2 is for this usage scenario do column-oriented DBs bring any other advantage?
Aug
5
comment Why use a column database for tick/bar data?
@JL344 You didn't mention the row-oriented approach of one table per symbol (see the UPDATE in my question). Is there a reason people are not using that approach?
Aug
3
comment Why use a column database for tick/bar data?
@Freddy Thanks for the update, sorry I only just saw it. It sounds like you are confusing NoSQL DBs (which, to me, means MongoDB, CouchDB, Cassandra, Redis, etc.) with column-oriented databases? Or do you regard them all as NoSQL solutions?
Jul
17
comment Are there any standard techniques for adding realistic synthetic microstructure noise to a price series?
@Serg Is this (using the difference between future and current) any better than using the difference between previous and current? I.e. your answer implies that if the market is about to get more volatile (bigger jumps between prices) then there is more noise in current. Is that an observable phenomena?
Jul
10
comment Why use a column database for tick/bar data?
@chrisaycock By "aggregate" do you mean things like turning ticks into 1m bars, 1m bars into hourly bars, etc.? And/or do you mean making moving averages and other more complicated indicators? And/or something else?
Jul
10
comment Why use a column database for tick/bar data?
Thanks @chrisaycock I had read one of those in my hunt yesterday, but the first link I'd missed and it was very informative (I'm still working through the linked 85-page PDF, but that looks useful too). I've added more information to my question to explain why I don't feel the linked-to answers fully answer my question.
Jul
10
revised Why use a column database for tick/bar data?
Explain why I don't think other similars questions are answering the question here.
Jul
10
revised Efficiently storing real-time intraday data in an application agnostic way
edited tags
Jul
9
comment Why use a column database for tick/bar data?
Another question: I usually think in terms of one table per symbol (instrument/contract). Reading between the lines of your answer, when you have a column-oriented DB do you keep all symbols in one table?
Jul
9
comment Why use a column database for tick/bar data?
Thanks for the reply Freddy. When you say column DBs are all about Key/Value, what is the key? When I think tick/bar data, the key is a datestamp, but that is a row-oriented concept, isn't it?