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: 2008-05-16 16:57:56

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Shamefully out of date contact info is available on my business card, but the email address, at least, should work.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

15 May 2008 (updated 15 May 2008 at 12:46 UTC) »

Monotone vs. git
Observe: Reconsidering the work flow and how the SCM system fits in on the Openembedded-devel mailing list.

Questions:

The motivation for the move was difficulties they had with mtn's propagate. What, I wonder, were they were doing different with their repositories than other users?
Mamona migrated their repository to git. How does this work? Are there conversion tools? Did they agree upon a time when all of the developers converted their repositories? Or did they have encroaching gradualism, where a gatekeeper converted, and others converted when they needed to talk to the gatekeeper?

Postscript: I guess tailor can handle the project migration.

15 May 2008 (updated 15 May 2008 at 11:48 UTC) »

Food prices: stabilisation?
The Financial Times observes that the UN FAO food prices index has stabilised, showing a tiny decrease for April (216.7, compared to the revised 217.0 for March). I'm guessing that this is a response to the high predicted wheat harvests for this year. This is, by no means, the end to the food price crisis, but it might end the recent supply panic.

Martin Wolf's column for two weeks ago, Food crisis is a chance to reform global agriculture, argued that speculation is unlikely to have played much role in the ramping up of food prices, since food price inventories have been so low. So we shouldn't expect any sort of speculative unwinding of food prices: they are unlikely to "bounce down" in the way that stock markets have done. Instead the reason for high food prices has been rapidly growing supply not keeping up with even more rapidly growing demand (part of which is the growing demand for meat, particularly in China) and cost of inputs to agriculture, particularly oil.

Paul Collier's comment on Martin Wolf's article argues that a general acceptance of GM foods, particularly in Europe, and promotion of large-scale agriculture (ie. industrialised), particularly in Africa, is an important part of any effective response to high food prices. Just threw that in, in case this post was lacking in controversial assertions.

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.

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