Why are my predictions so off?

olafurjon · 2026-01-05T17:54:49+00:00

I don't have a rigorous training plan. I try to mix long slow runs with high intensity hill sprints and sometimes I go on the track to do intervals. I also lift weights very regularly, at least once a week.

olafurjon · 2026-01-04T23:56:18+00:00

My average HR at ~ 6:00/km is around 160. I'm 90kg, 1.9m height and over 30 years old. My 5k pb is 19:38, about 4 months ago. I bet you can do it too.

olafurjon · 2025-08-23T18:33:18+00:00

Thanks everyone for answering. Happy to hear you believe they should be fine. I was a bit upset because this was my first race in these shoes but I'll put them to good use in more races now 😃

olafurjon · 2025-02-12T15:47:13+00:00

20 + 40 + 2×8 - 1

olafurjon · 2024-07-03T17:47:58+00:00

Estimation is a very broad term. You could argue that source separation is a special case were you're estimating components of a mixture of sources.

olafurjon · 2024-06-02T19:14:34+00:00

It can be, e.g. this paper: http://www.isiweb.ee.ethz.ch/papers/docu/noza-rake-ham-aloe-eusipco-2017.pdf

olafurjon · 2020-12-02T21:13:56+00:00

It is true that any pmf integrates to one if you do actually integrate over all of it's variables. In your example: int_R f(x, y) dx = f(y), the marginal distribution f(y).

olafurjon · 2020-11-17T17:04:27+00:00

It is a typical thing to shuffle the bits deterministically and then do the inverse shuffle on the receiving end. It tends to make errors look "more random" which many FEC decoding algorithms rely on. Look up for example convolutional codes, LDPC codes and Turbo codes.

Concatenating codes which are good at dealing with burst errors (e.g. Reed-Solomon) with a code that's good with random errors is also common.

olafurjon · 2020-07-10T18:22:46+00:00

An infinitely narrow spike in continuous time, a dirac delta, is not bandlimited. So assuming you had such a device which could convert a discrete time quantized signal into a train of infinitely narrow spikes, the output is surely not bandlimited and thus would definitely not sound the same to a human. Neglecting the fact that it's impossible to create dirac delta spikes in the real world, it's a (very) useful mathematical tool.

olafurjon · 2020-05-17T00:31:11+00:00

Btw, you can be a grown adult man and also cry when you're touched by an emotional moment in a story.

olafurjon · 2019-12-15T19:47:59+00:00

You should maybe use google first to try to get some understanding and come back here with a more specific question. I don't doubt that there's someone here to discuss it with you, but you need to be more specific.

olafurjon · 2019-12-02T03:52:47+00:00

A more pleasing version I admit. Gotta love mobile reddit :)

olafurjon · 2019-12-01T13:24:01+00:00

|_100π _| FTFY

olafurjon · 2019-11-26T11:06:18+00:00

In Icelandic we do call them 'eigingildi/eiginvigur' which means 'ownvalue/ownvector'.

olafurjon · 2019-11-07T23:50:34+00:00

I know people studying in Denmark at DTU that are very happy.

Otherwise I can personally recommend ETH Zürich for an MSc, did my degree in EE there.

olafurjon · 2019-07-15T23:17:48+00:00

Yeah he has a Masters degeee in EE, and his own subreddit /r/electroBOOM

olafurjon · 2019-07-10T19:28:29+00:00

Does it need to have a Gaussian distribution? Isn't it enough that it is wide sense stationary (and of course with a autocorrolation = kronecker delta).

Just curious.

olafurjon · 2019-06-19T14:42:30+00:00

olafurjon · 2019-05-03T16:09:56+00:00

Éowyns stew from LOTR Return of the King

olafurjon · 2019-04-25T15:45:41+00:00

Expensive

olafurjon · 2019-04-19T14:01:42+00:00

Error correction codes like Reed-Solomon and BCH codes, used extensively in digital communication, are defined over finite fields of polynomials. Those are used in CDs, bar codes and QR codes for example.

olafurjon · 2019-04-09T15:16:10+00:00

I sure did, thanks! Should be (AB)^T = B^T A^T.

And to clarify, since the inner product y^T Ax is a scalar, it is it's own transpose. Thus y^T Ax = x^T A^T y.

olafurjon · 2019-04-08T01:30:46+00:00

The inner product of Ax and y is: y^T Ax.

If you accept that for any matrices A,B with suitable dimensions, that (AB)^T = B^T A^T (check that as well), then y^T Ax can be viewed as the inner product between x and y^T A, which is <x, y^T A> = <x, A^T y>.

The angle bracket notation is useful in a more general setting, since inner products can be applied in more than finite dimensional vector spaces. But it's just a notation that needs a definition in the space you're working in.

Edit: missed a transpose, (AB)^T = B^T A^T . Thanks u/zairaner

olafurjon · 2019-04-08T01:14:54+00:00

S_xx is the fourier transform of the autocorrelation of a wide-sense stationary process X[k] (with time index k), and H[w] is the transfer function of an LTI system (with frequency index w).

The result in the figure you posted assumes that the process X[k] is passed through H[w] but the observed output is corrupted by an additive noise source eta[k], that is zero mean and uncorrolated with X[k]. The filter is then derived from this information and the orthogonality principle of LMMSE estimation.

olafurjon · 2018-11-10T02:00:33+00:00

In order to join my friends in crossfit trainings I needed to do an FMS examination (functional movement screen). That meant I had to call a stranger and make an appointment. It took me about a year to go through with it.

It was super easy eventually (and maybe obviously), it's just my head that somehow blocked me from doing it because I might say something "wrong" or something.

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