Jan Krüger's blog

Cola improvements - with science

jk@jk.gs (Jan Krüger) — Mon, 23 Dec 2019 14:55:41 +0100

The most challenging part of making your own cola is getting a proper and stable emulsion of the flavour oils in the concentrate (and beyond, when actually making cola from that). If the emulsion isn’t all there, any of the following could happen:

Making Cola

jk@jk.gs (Jan Krüger) — Fri, 12 Jul 2019 00:28:13 +0200

I don’t even remember why I started, but I mix my own cola from first principles. It’s a fun hobby and I get to experiment with the flavour components – therefore, in theory, ending up with a cola that’s particularly close to what I like. It’s been taking a fair number of iterations, though. I’m currently on my third batch (two of 45 litres, this one is 22.5 litres). Here’s my journey, including the fine details that some other sources don’t mention. I’ll close with the recipe I used and what I’ll change in the next batch.

Goodbye, Wordpress

jk@jk.gs (Jan Krüger) — Tue, 15 Dec 2015 17:39:55 +0000

For about eight years this blog was powered by WordPress. When I tried to upgrade to HTTPS (thanks, Let’s Encrypt), I ran into slightly insurmountable issues with resource URLs generated by it. I never really liked WordPress all that much, anyway, beyond the sheer convenience, so I decided it was time to move on. I’ve always been fond of static website generators, because they remove most of the work the server has to do when someone tries to view a page, and so I started looking for one that can do both blogging and other stuff, and is reasonably customizable.

How to sing well, part 1: harsh reality + survival guide

jk@jk.gs (Jan Krüger) — Sat, 26 May 2012 01:02:18 +0000

Well then. There’s been a tiny little bit of interest. Good enough. Let’s talk about the fundamental requirement for getting better at singing – according to me, anyway. It’s in how you approach the whole process.

As I’ve said throughout the intro to this series, becoming an awesome singer consists of three kinds of tasks: doing the less of the wrong things, doing more of the good things, and doing both of that more consistently. All of these need to be approached in slightly different ways, but there’s one thing common to all of them:

You have no idea.

How to sing well: an introduction

jk@jk.gs (Jan Krüger) — Sat, 18 Feb 2012 01:09:04 +0000

Okay, this is hardly a new topic on the internet… but it’s yet another new topic on my blog (the strategy is to have as little focus as possible and thus make it completely impossible to “monetize” the blog). The topic, formulated as a question, is: how do you improve your singing? And your speaking, I guess. The problem with that topic is that there’s a lot of information about it on the internet, much of it either wrong, misleading or irrelevant. So I thought I’d add some more noise, and I’ll try to give you a few explanations of why I think certain parts might be more or less useful.

So, here’s an introduction to all the stuff you’ll find on the internet, and which parts of it really matter (if you ask me). (Note: I made substantial changes to this article shortly after first publishing it.)

dmsetup-tc: now works on 64 bit systems

jk@jk.gs (Jan Krüger) — Thu, 19 Jan 2012 13:21:29 +0000

Well, this is embarrassing. I thought I had done everything to avoid portability problems. But in trying to avoid them, I stepped right into them, doing something that by now I know very well not to do. Oh well, here’s an updated version of dmsetup-tc (which you can use to mount TrueCrypt®-encrypted Windows system drives/partitions on Linux). It’s no longer really necessary since the Linux version of TrueCrypt® added support for this back in version 6.

Open source licenses quick reference

jk@jk.gs (Jan Krüger) — Fri, 11 Mar 2011 01:04:26 +0000

There are a lot of open source licenses. Even if you look at only the OSI approved ones, that’s still a list of 67. And, of course, they are all different in subtle (and not-so-subtle) ways. Can you keep all the small details straight in your head? I know I can’t. That’s why I just made a quick reference page: HTML version: http://j.mp/opensource-licenses PDF version: download (A4 paper, 46 KB) It focuses on just a few commonly used licenses (at least from what I can see), but covers more criteria than the other comparisons I’ve seen so far.

mod_gnutls and StartSSL level 1 certificates: the problem (and solution)

jk@jk.gs (Jan Krüger) — Tue, 14 Dec 2010 20:49:47 +0000

Update: This patch is pretty outdated. There have been major rewrites in mod_gnutls since then. I’m not sure whether the current version properly supports subjectAltNames; I don’t use mod_gnutls myself anymore.

Yesterday, I wrote a small patch against mod_gnutls (that’s the GNU alternative to mod_ssl, and it’s leaner; and it supports SNI (server name indication), whereas even the version of mod_ssl in the upcoming Debian squeeze release doesn’t). It took me quite a while to figure out the problem in the first place, and I guess it’s a bit of a corner case, but I can’t imagine I’m the only person who might run into this problem, so here is an explanation.

Host your own (di)graph pastebin

jk@jk.gs (Jan Krüger) — Mon, 24 May 2010 00:34:16 +0000

I just had some time to procrastinate away, so I built a little open source graph pastebin web application called Instagraph. It’s based on GraphViz, PHP, MySQL and Apache. At least the first three need to be installed on your web server, and the fourth one is necessary unless you tweak your way around using the included .htaccess file (which makes use of mod_rewrite).

I’ve been wanting to write something like this for ages. Often enough I want to explain concepts in IRC and find myself struggling to present all the relationships between different things in an understandable way. Now I can just use a private Instagraph instance to make a nice picture that will speak a thousand words for me. Awesome.

Instagraph is woefully underdocumented but shouldn’t be too hard to set up. It’s also extremely simple and has no user interface to speak of.

Intuition for the unintuitive

jk@jk.gs (Jan Krüger) — Wed, 17 Feb 2010 22:35:36 +0000

Intuition is an interesting concept, and I believe that it’s a bit hard to really make sense of for people who don’t consider themselves intuitive. At least it didn’t make a lot of sense for me a year or two ago.

I suppose many think that intuition is something you are born with… some people just “know” certain things without being able to reason them out, and other people have to conduct an elaborate analysis of the facts in their minds to end up with the same conclusion. If that’s the way you think about it, you might believe that intuition is something of an unfair advantage.

Another widespread position seems to be that intuition is very risky… after all, intuition doesn’t give you the certainty that logical reasoning can give you, right? So perhaps if you go by that idea, you might say that it’s better to not use intuition at all.

I think that the answer is somewhere in between, as it often happens to be… and I’m going to tell you how intuition became a natural thing for me, even though I wasn’t exactly born with it, nor did I think it made sense to trust in it. But now I do have it, and I do trust it, because I use it in a way that I’m confident in. And don’t worry, I’m not going to cite the usual hogwash about left brain versus right brain… I’ll just explain a useful way of looking at intuition, and I’ll also waste a few words on how important I think it is for knowledge engineering.

A scientific defense of pseudoscience

jk@jk.gs (Jan Krüger) — Tue, 22 Dec 2009 22:55:05 +0000

Pseudoscience is significantly worse than what science claims to be, and that’s the problem: science isn’t actually what it claims to be. Many people who boast about their extremely scientifically oriented thinking don’t actually know what science is, and they’re actually thinking religiously or even dogmatically.

Whew. That’s a rather provocative first paragraph, isn’t it? I’ll have to be extremely scientific to avoid getting shouted at by would-be scientists. Don’t worry, dear scientists, I’m not against science! I’m a huge fan of it. Until some “scientist” starts making overly general statements. That’s where it stops making sense. Why? Well, let’s have a brief look at how science works.

Relatively absolute philosophy

jk@jk.gs (Jan Krüger) — Tue, 06 Oct 2009 16:32:14 +0000

Here is a (not necessarily complete) list of philosophical “isms” that I believe in. I don’t believe in “isms” lightly at all, because I feel that adopting an “istic” view is a rather drastic thing to do.

The following list will give you deep insight into the way I understand life, reality and science… if you want to find out, that is.

Stereo Pan 2.0: now with "subtle mode"

jk@jk.gs (Jan Krüger) — Wed, 19 Aug 2009 23:02:00 +0000

Oh well, better late than never. I present to you the next version of Stereo Pan (announcement for previous version), introducing a second mode of operation: the subtle mode. It’s called that because its effect is more subtle. Duh. A great property of it is that it doesn’t distort the sound if the output is downmixed to mono. If you downmix to mono while using Stereo Pan in its normal mode, you get a flanger-style effect on the sound.

My first journey into writing VST plugins: a stereo expander

jk@jk.gs (Jan Krüger) — Thu, 30 Jul 2009 08:20:47 +0000

(A newer version is available!)

So perhaps you noticed that I’m a musician and also a coder. What better than to combine both of those and write software I can use when making music?

My first project for this was writing a VST plugin (VST is a trademark of Steinberg Media Technologies GmbH and it’s basically an effect interface supported by a large number of DAW applications) that does stereo expanding. What’s that, then?

A trick that’s well known among musicians and mixing engineers for making something sound fuller is to record the exact same thing twice and then superimpose these two takes. A special case of that is putting one take in the left stereo channel and the other in the right. If you do that, it will sound a lot “wider” in the song, and it will also dominate the overall sound of the song a lot more.

Sometimes, though, you’re short on time or don’t have two takes of something handy (or it’s actually impossible to get two takes). Enter stereo expanders! They basically pretend that you recorded two takes, and pan them left/right for you. I’ve got one right here for you, and it’s free to download.

Pain made useful: a story

jk@jk.gs (Jan Krüger) — Sat, 30 May 2009 15:35:44 +0000

I haven’t posted anything for months, but I feel very strongly about an experience I had yesterday and I want to tell you about it. This is a story involving a person who had been feeling extremely strong pain for months and months, and myself.

At first glance this post will look like it’s rather unrelated to what I have posted about before. In fact, it’s about the human mind and about how it works, and about how it changes.

Please understand that I have to suppress a lot of details and slightly warp the story to protect the identity of that person. I just flipped a coin to determine that I’ll be presenting that person as male, and I’ll call him Chris. I don’t know any person called Chris, so I guess that’s okay.

So Chris had been trying everything he could find. Pain medication, stronger pain medication, elaborate diagnostics, alternative approaches to healing, everything. All doctors pretty much agreed that there was no physiological basis for the pain. Chris found that hard to accept, because that had to mean that it’s a psychosomatic thing; a signal from the body that things aren’t going right… a signal that change needs to happen. Still, he started looking into psychotherapy. A few attempts had no real effect; at some point he found a therapist who could indeed help him reduce the pain for a while (in exchange for a lot of money, of course). A permanent solution wasn’t in sight, though. The last thing he tried was an inpatient therapy, during which on some days he actually felt really good… but there wasn’t any method to it. The pain would keep on coming back.

Then we met, and we talked about it.

Managing your web passwords the portable and secure way

jk@jk.gs (Jan Krüger) — Sat, 07 Feb 2009 01:43:51 +0000

Dear users of browsers other than Firefox, I’m not talking to you now. Sorry. Dear remaining readers, have you ever disliked having to a) remember all of your different passwords for all websites or b) store them on your local computer so you can’t get at them from other places or c) use the same password everywhere even if that makes the impact of security issues a lot worse? I used to go with option b) but I didn’t really like it. Now I’ve found something else; allow me to share.

Song Fight(ish): Paper Thin

jk@jk.gs (Jan Krüger) — Mon, 22 Sep 2008 05:45:47 +0000

The submission timeframe for the current Song Fight, “Paper Thin”, ended four days ago and the submissions were just published. Unfortunately I didn’t manage to submit my song in time (I recorded most of it in the last few hours) but you can listen to it anyway.

Song Fight: Interesting Times

jk@jk.gs (Jan Krüger) — Thu, 04 Sep 2008 00:47:24 +0000

Good news! A couple of weeks ago I found the Song Fight website. Song Fight works like this: a song title is posted. You write a song for that title within a week and submit it to the fightmaster. When the week is up, the fightmaster will publish the list of all entries on the website. Visitors can now vote for songs until the songs of the next fight are published. The winner of a fight gets to brag… and not really anything else. Apart from a serious boost in creativity and musical skills when you make it a habit to participate, that is.

Yesterday (going by the local timezone) I submitted my first Song Fight entry for the title “Interesting Times”. It will be up on the Song Fight website shortly, and it’s now available here.

Using TrueCrypt®'s encrypted system partitions from Linux, now with less bugs

jk@jk.gs (Jan Krüger) — Sun, 17 Aug 2008 15:30:11 +0000

Take note if you had problems using dmsetup-tc, the program I published last month that allows you to use TrueCrypt®'s encrypted system drives/partitions (also called the “pre-boot authentication” feature) from Linux environments (and possibly other Unices). I have found a few rather embarassing bugs in it that made it rather unusable in pretty much all cases (it’s actually really astonishing that it even worked for myself…). So if previously you got a cryptic message like “fatal error: Success”, now would be a great time to try again.

How to use TrueCrypt®-encrypted Windows system drives on Linux

jk@jk.gs (Jan Krüger) — Wed, 23 Jul 2008 09:36:27 +0000

Update: I made this program in 2008. In the meantime, some other guy appears to have written his own, apparently much more complete re-implementation. Feel free to check it out here: https://github.com/bwalex/tc-play – chances are that if that one works for you, I won’t be updating dmsetup-tc anymore.

TrueCrypt® is a multi-platform on-the-fly drive encryption tool. It allows you to encrypt all your data in a filesystem and still use everything normally. On Windows, it supports encrypting the system (boot) partition (or the entire boot drive); you can even make TrueCrypt® encrypt your existing partitions live and continue working (though the I/O performance sucks until it’s finished encrypting everything), pause and resume the encryption process (even across reboots). In short: it’s rather useful.

Even though TrueCrypt® introduced Windows system encryption in version 5.0 in February 2008 (that’s five months ago), its Linux version still doesn’t support accessing these encrypted partitions at all (it does mount “normal” TrueCrypt® volumes though). Since I recently encrypted my entire Windows drive but couldn’t live without the music files stored on it, I now humbly present the result of two wasted nights: a solution.

Finally: the perfect CAPTCHA

jk@jk.gs (Jan Krüger) — Tue, 22 Apr 2008 17:11:03 +0000

CAPTCHAs: these warped images you have to copy text out of in order to submit comments on an ever-growing number of websites. The warped image approach has a number of serious flaws. Firstly, there is a strong correlation between the difficulty bots have with extracting the code from the image and the difficulty humans have with extracting the code from the image. In some cases, I hear it’s actually easier for machines than it is for humans.

My first take on the "Album A Day" challenge

jk@jk.gs (Jan Krüger) — Sun, 20 Apr 2008 23:18:00 +0000

Tom7, also known as Tom Murphy VII, has been challenging musicians to create an entire album in 24 hours. Consecutive hours, that is. In other words, this challenge is an excellent source of sleep deprivation and a great way to avoid doing things I ought to be doing instead. So I thought to myself: one day I simply must give this a try. That day was today (and yesterday). I proudly present my first Album-A-Day: You Vs.

HOWTO: encode a string into a complicated-looking trigonometric function

jk@jk.gs (Jan Krüger) — Thu, 03 Apr 2008 20:49:19 +0000

Today’s glance at reddit.com yielded a blog posting by a fellow who calls himself “Poromenos” and who recently wasted his day by designing a function made up of sines and cosines that encode the string “Hello world!". “Hey”, I immediately thought, “I can do that too! I’m an expert at wasting my day, after all.” Only I decided to go a step further and write a program that generates this sort of function. I’m lazy, remember?

Why Humanity Is Blocked

jk@jk.gs (Jan Krüger) — Sun, 25 Nov 2007 20:04:20 +0000

Please read carefully the following important message that does not come from the anonymous persons running whyfirefoxisblocked.com and whydiggisblocked.com. You’ve reached this page because the site you were trying to visit now blocks visitors from the human race and other beings capable of browsing the web. The users on continents such as America, Asia, Europe and Antarctica openly endorse critical thinking, a function of the human brain that allows humans to ignore irrelevant perceptions such as advertisement on web sites, and are well known for paying no huge amount of money to the owners of sites they visit.

Git cheat sheet, extended edition

jk@jk.gs (Jan Krüger) — Wed, 19 Sep 2007 00:51:52 +0000

A few days ago, I posted a cheat sheet for Git (just as last time, Git is a really cool revision control system). Let’s face it: it was ugly. Not something you would actually hang up where other people could see it, was it? Here’s the remedy, which also works on both A4 and Letter and is more detailed.

Git cheat sheet, take two

jk@jk.gs (Jan Krüger) — Thu, 13 Sep 2007 01:22:41 +0000

Update: Since I first posted this, I have created a new and (in my opinion) better Git cheat sheet. You might want to have a look at that one.

Today I came across Zack Rusin’s Git cheat sheet (just so we’re on the same page: Git is a really good distributed revision control system). I quite like the idea but unfortunately, Zack’s design is fairly useless to me because

the colors don’t print well on black and white;
it’s designed for Letter paper. Letter paper doesn’t exist around here. Give me A4.

While trying to change Zack’s file to address these issues, Inkscape kept crashing on me until I finally gave up and just started from scratch (in – don’t tell anyone – OpenOffice.org Draw). This is the result: Git Cheat Sheet (A4 PDF version).

Problems in life engineering

jk@jk.gs (Jan Krüger) — Wed, 25 Jul 2007 19:15:30 +0000

Okay, so there are problems in knowledge engineering, AGI in particular (to recall, AGI is a machine or program that can demonstrate intelligence on the complexity level of humans). More generally, in every domain of sufficiently complex structure, AI fails, sometimes spectacularly. A well-known example is the board game Go, for which nobody has managed yet to design a computer opponent that can beat players above the level of novice.

Yet humans manage many of these tasks seemingly without any problems. One might be tempted to think that the human brain is the ideal “thinking machine”. In reality, it has a staggering number of bugs which produce incorrect actions or results in a variety of situations.

Problems in knowledge engineering

jk@jk.gs (Jan Krüger) — Mon, 21 May 2007 23:42:46 +0000

Given the “right” philosophical attitude about how the world works, the ultimate goals of knowledge engineering, namely obtaining, processing, using and making accessible all kinds of knowledge, can definitely be achieved. This set of bold goals, however, presents researchers with very difficult problems. All attempts that exist today are restricted to small classes of knowledge.

Life, knowledge engineering and everything

jk@jk.gs (Jan Krüger) — Wed, 18 Apr 2007 11:32:58 +0000

What do life and knowledge engineering have in common? Everything. There, that’s all keywords from the topic. But I guess you’d like a little more detail.

About this site

jk@jk.gs (Jan Krüger) — Wed, 18 Apr 2007 10:57:55 +0000

Hi, my name is Jan. Thank you for stopping by on my personal website! Content Without further ado, let me tell you what you can not find here: Loads of personal information. I have maintained a website with information about myself and my general beliefs in the past, but I believe that this website is interesting to a larger audience and I can’t do everything at once. Additionally, rambling about yourself all the time gets old after a while.

Minimalist Code of Conduct

jk@jk.gs (Jan Krüger) — Mon, 01 Jan 0001 00:00:00 +0000

We believe that an elaborate code of conduct invites a lot of fighting over intricate details, much like law, and we do not have the resources to build up the equivalent of a legal system. Therefore we prefer keeping our rules as short as possible and filling the gaps with the mortar of human interaction: empathy. All we ask of members of this project is this: Please treat each other with respect and understanding.