Advogato: Personal info for chalst

chalst is currently certified at Master level.

Name: Charles Stewart
Member since: 2000-09-19 22:55:04
Last Login: 2008-05-09 18:37:55

Notes: Contribute to free software? Well...

I'm a freelance copy-editor and consultant working from Berlin, working mainly for academic publishers in computer science, philosophy, mathematics and linguistics. Until May 2006 I was a post-doctoral theoretical computer scientist . I use and promote all kinds of free software tools, such as pdftex, Gnu ghostscript and libart.

I'm in a 18 year love-hate relationship with UNIX, and I've been using GNU utilities since my very first days. I've been aware of Linux since about 1994, but only took the plunge of using it in early 1999. Today I use Debian Linux linux and FreeBSD most days, though I'm mostly using a non-free OS to provide my GUI...

I've been coding for 25 years (started on a Sinclair ZX80) but mostly for personal consumption or a few of my close colleagues. I have rather a preference for functional languages, though I use C, C++, Java and Objective C when they are appropriate, and I make a lot of use of Tcl for system admin tasks. I haven't made much in the way of substantial contributions to important free software projects.

Shamefully out of date contact info is available on my business card, but the email address, at least, should work. I post comments more often to Lambda the Ultimate than here; I don't often crosspost.

Projects

Contributor on librep
Lead Developer on scol
Helper on scsh
Contributor on Wikipedia

Articles Posted by chalst

David Welton's Language Popularity article 25 Sep 2004 at 17:34 UTC
Today is the second anniversary... 11 Sep 2003 at 12:06 UTC
The DOJ abdicates its ethical responsibility 28 Jan 2002 at 11:59 UTC

Recent blog entries by chalst

Syndication: RSS 2.0

24 Apr 2008 »

Food prices: the ideological assault on food security
Daniel Davies asks What's that got to do with the price of wheat, rice, maize and ethanol?, talking about the dismantling of food security infrastructure in the third world, carried out in the name of free market dogmatism. Quote:

I think the underlying idea, in as much as there was one, was that international aid was a more efficient way of providing food security than domestic reserves and price controls. Which has a certain plausibility to it, as long as you only look at one country at a time and assume that food shortages will be caused by ecological famines, which are more or less uncorrelated between regions, rather than a global inflation in food prices which overwhelms the capacity of the food aid industry, and which arrives at a time of fiscal strain in donor nations. Of course, the general approach of assuming that one's risks are uncorrelated and manageable is one that has been causing all sorts of problems in the world economy of late.

22 Apr 2008 (updated 22 Apr 2008 at 12:36 UTC) »

Some trust-metric references
All the references listed below link to PDFs, with my comments in italics.

Weeks, 2001. Understanding Trust Management Systems. Crucial paper for understanding much recent work on trust-metrics. Presents framework, motivates it with examples, and shows PKI can be modelled using it.
Carbone, Nielsen and Sassone, 2003. A Formal Model for Trust in Dynamic Networks.. Proposes a simple domain- theoretic formalisation of what a model of trust is that provides the basis for some significant later work.
Twigg and Dimmock, 2003. Attack-Resistance of Computational Trust Models. Synthetic exposition of several trust-metrics that have some degree of attack resistance. Good exposition of Raph's metric, sgives alternate proof of attack resistance by order-theoretic reasoning.
Moreton and Twigg, 2003. Trading in Trust, Tokens, and Stamps. Proposes system for adding trust trading to trust-metrics by stamps, and argues for advantages of this system. Interesting for Advogato: could provide a more principled means of bringing in new members than just rejigging weights.
Ziegler and Lausen, 2005. Propagation Models for Trust and Distrust in Social Networks. Motivates criteria for success of trust-metrics when applied to social networks, including attack resistance. Proposes a new algorithm, which they call Appleseed and which is based on the spreading activation technique, which they compare to Raph's version. This work is based in part on Ziegler's PhD thesis, Towards Decentralized Recommender Systems.

I'm curious as to the origin of Raph's talk of "good", "bad", and "confused" nodes. Is it his novel usage, or did he get it from elsewhere?

I'm amused also to read references sections that cite Raph's abandoned trust -metrics thesis as if it was a successfully defended one. Folks who run into the thesis he did write will no doubt conclude he is one of the select few who wrote two PhDs concurrently...

17 Apr 2008 »

Food prices
I've been thinking and worrying about food prices more and more over the last four weeks, and I see that skvidal shares my worries.

In fact, he doesn't worry enough! When he talks of food prices "spiking", there's more to the story. The S&P-GSCI agricultural commodity price index, which is the main aggregate food price index, has shown a nearly three fold increase from Jan 2005 until the beginning of this year. Given the terrible access to credit poor farmers face, this is likely to mean that food prices, already difficult for many to afford, will get higher as the year progresses. If there is nothing done to relieve the situation, it will spell immense suffering and political instability in much of the world.

It's a scary picture, and if it isn't ignored by the world media, not enough attention is drawn to just how serious this all is. It's pretty damn clear that the story matters more than the bloody farce in Iraq (which has contributed to it by pushing up oil prices), and it is more important than the financial turmoil shaking the world right now (though that will make it harder to do anything to help).

Can we do anything to help? Skvidal has suggestions: I wonder if growing food is an option for me? lkcl's article Singularity of computing, might have something to do with food price stability in the future, though I don't suppose this kind of thinking about technology can help with this year's crisis.

13 Apr 2008 »

What should I believe?
On Friday, the Financial Times tells me how Germans feel Schadenfreude towards Anglophone countries, because the economic pain those countries are suffering will pass them by, because of the fairly healthy state of the German finance system, growing internal demand, and because the peculiar makeup of Germany's export markets puts it in a good position to weather the coming global economic downturn.

On Saturday the Financial Times tells me how Germany is headed for a nasty fall, because domestic demand is faltering, and its export-centric economy is particularly vulnerable to the coming global economic downturn.

26 Mar 2008 (updated 26 Mar 2008 at 12:22 UTC) »

Advogato certifications again
I've just certed henrique, despite his not having a link to anything identifying him and saying what free software projects he is involved in.

This is generally against my policy, but the Henrique Romano involved in Django and some other python projects doesn't seem to have a home page, and he does post contentful diary entries here, so...

As a general point for newcomers seeking certs, I, and I think others, pay more attention to diary entries than account creation, and to some extent I trust local diary content more than RSS feeds.

186 older entries...

chalst certified others as follows: