Monday, January 30, 2006

Uit het schetsboek van... 

My brother Barthel Brussee started his own blog Uit het schetsboek van.... He is an artist, so he has an interesting life and has the progress of his painting and sculptures to show. He is quite productive (one post a day).

I think I should put some of his work on the special new streetart recommendation website produced by students of the HKU (hoge school voor de kunsten)
ondergrond. Check it out at www.ondergrond.org

Uit het schetsboek van... 

My brother < href= "www.barthelbrussee.nl">Barthel Brussee started his own blog Uit het schetsboek van.... He is an artist, so he has an interesting life and has the progress of his painting and sculptures to show. He is quite productive (one post a day, he has more posts than I ever did), and he writes well (in Dutch) I think!

Hmm, I think I should put some of his work on the special new streetart recommendation website produced by students of the HKU (hoge school voor de kunsten)
ondergrond. Check it out at www.ondergrond.org

Tuesday, December 20, 2005

Anjo Anjewierden: What is a Topic? 

Because it is the holliday season, Anjo Anjewierden asks what is the topic ?. Now anybody who has ever attended a party (which are seasonally superabundant at the moment) and casually joins in a conversation, knows that it may take a while to actually find out. One reason is ofcourse that some conversations (especially at parties) serve no other purpose than giving the participants the idea that they belong to the same group, or, like the more flirtatious ones, that the participant(s) want to raise the level of intimacy. Thus, if you are an outsider to the group, you may come to the conclusion people are discussing work, when what they really do is building on the shared experience they have, to stress their commonality and shared interest. To some extend that seems to be the case for blogs as well, especially if they address a community that is somewhat interacting. However at least I would already be quite happy when we can detect the more superficial topic automatically.

Lilia equates the topic with the tag you would be putting on document like a blog. She has a point, but I would think that a tag's primary purpose is to make it possible to find something back by generating enough and sufficiently general associations (mirroring the precission recall dichotomy in information retrieval). On the other hand I think that, when asked the question "what are you talking about" I think they will try to give characterisation that is sufficiently precise in a given context. In a sense this may explain why Anjo is succesful with a simple information retrieval measure like TF/IDF, which is after all designed to find terms that are distinguished in a document compared to other documents (the context !). Without having read the full conversation a word like Blogwalk, Sigmund or Skype, may be quite enough as a characterisation. On the other hand Lilia, who has been engaged in the conversations, has more of a context. She will therefore subconsciously remember similar dicussions and change her context correspondingly.

Now what do I mean by similar discussions? I wish I knew exacty, but lets take the discussion on skype and pressence as an example. They both have high frequency and high TF/IDF in this discussion. In falling measure of TF/IDF score Anjo finds presence, Skype, communication, IM (= Instant Messaging, I guess), communication tool. Knowing Lilia, I know that she knows, that skype is a communication tool that supports instant messaging and presence, and that presence is the capability to tell whether you are avalailable for communication (so there you have ontological relations). Now what does it mean that Lilia remembers similar discussions. I don't know exactly ofcourse, because I don't really know everything she has read, and moreover the human brain is subtle. But let us suppose that using her ontological knowledge she will first "score" a hit for communication tool for every mention of skype, and score a "bit of a hit" for presence and quite a bit for communication (because this subject is dear to her hart). This puts communication tool, presence and Instant Messaging higher up the list. Again knowing Lilia, I know that she read blogged and talked about these subjects. Thus, consiously or subconsciously, I think she subconsciously changed her context (if you want to think in IR terms, changed the "document collection in which to compute TF/IDF scores) and asked herself what is it that characterised this dicussion in this more specialised context. In this context (and her social and blog circle) skype, IM and presence are not so characteristic anymore, so my guess (not having read the discussion) is that she comes up with a characterisation like

presence with skype

or likely more specific characterisations such as

How do you switch on presence in skype


presence in skype is really great/awful/mediocre


skype now does presence too !



It is thus not so surprising that she wants to have a Sigmund type cooccurence analysis of the conversation, because cooccurrence tends to emphasize the relations between terms rather than just the terms themselves, although being a statistical method, it cannot really see what kind of semantic relations may underly observed cooccurences.

Now I hope I know Lilia well enough, that my belief that she does not mind me blogging about what she thinks, is true :-).

Wednesday, November 02, 2005

The nonsense of 'knowledge management' 

Yesterday Anjo Anjewierden and I noticed that my blogs hardly, if ever, mentioned knowledge management. Today Olga Steen pestered me to look into knowledge management journals. This made me stumble into this blistering but IMHO mostly accurate analyis of knowledge management of professor TD Wilson as a cut and paste replacement for information management and training from management consultancies. Fortunately that didn't stop Anjo and me from having a fruitful discussion on how to get a grip on (proxies of) knowledge flows.

Monday, September 12, 2005

Jephte, an oratorium by G. Carissimi, september 17, 2005 11h, Jacobus Kerk Enschede. 

My choir montessera, the soloists Ilse van Griensven, Govert Valkenburg and Steffen Posthuma will perform Jephte, a beautiful oratorium by G. Carissimi (1605-1674). The choirs Il crocodillo cante and kamerkoor twente will perform "Musikalische Exequien" van H. Schütz. Both choirs are conducted by Jeanet Bosch. The performances are part of the Enschede Muziek Festival . You need a festival button to attend this, and many other performances. Choir members, like me, sell them for 5 euro.

time : saturday september 17 2005 11:00h.
location : Jacobus kerk Enschede
requires : festival button for 5 euro

Carissimi's oratorium Jephte is something like a small opera. The storyline, indeed large parts of the (latin) text, come straight from Judges 11. It is a dramatic story. Jephte (Jephthah) is called upon by the people of Israel to lead them into battle against the Ammonites. If you have just read Judges 11, you know that Jephte has an axe to grind, being the illegitimate son of Gilead and having been send away from his ancestral home for that reason. We are also informed that the casus belli echos problems we are only too familiar with in 21st century middle east: fertile lands have been promised to different people by their different gods. In Carissimi's Jephte this information is ignored. The historian (sung by the bass Steffen Posthuma) merely explains that the Ammonites have not been behaving reasonably and that Jephte is forced to lead Israel into battle against them. Then the central drama is set in motion: Jephte (sung by the tenor Govert Valkenburg) promises to sacrifice as a burn offer (holocaustum) the first being that will come from his house (primus de domo mei) if he is victorious. It is a solemn oath to plea for the favours of a jealous God. Jephte needs all the help he can get, and Israel is in great danger but it is a reckless gamble none the less. My girlfriend told me that her mother would tell her that Jephte expected his little dog to greet him. Cruel enough for a child, but Jephte lives in an age when human life had a different value, certainly of less value than honour and glory.

Jephte goes into battle and fights. He and his army drive back the heathens (fugite!, cedite! impii!, flee!, backward!, thy heathens!), and the Ammonites run for it (corruite). Twenty Ammonite cities are wiped of the earth in one big sweep. Finally, the Ammonites are humiliated before the Israellites while loudly lamenting their fate. Interestingly, Carisimi makes this "ululantes" sound very sad, it is the victims that we hear lamenting. An alternative interprestation is that victory marks the point where there is no going back and fate will take its inevitable course. Jephte promised sacrifice to God on victory, and God has delivered. In the next "scene", Jephte lives his finest hour: all of Israel is praising its leader in war who bestowed them with glory, honour and victory (laudemus belli principem, qui dedit nobis gloriam et Israel victoriam).

Returning home, his daughter, his only child, comes out of the door with tambourines to sing his praise. Fate has struck. Jephte immediately realises what has happened and cries out in pain to his daughter (heu, heu filia mea). His oath has entangled both of them in the web of fate (decepisti sum, et tu pariter). Jephte's daughter (sung by Ilse van Griensven) while seeing her father's anguish, fails to understand it (cur pater, decepisti sum). So Jephte, howling of sorrow, explains that he has sworn to God will have to sacrifice her in a burn offer. Jephte's daughter accepts fate. She offers herself as a sacrifice for the glorious victory of her father and her people(ecce, filia tua uni genita, echoing the ecce homo of Gods only son Christ) . She merely begs for one favour. Jephthe is only too glad to offer some comfort, however small, to her grave heart. She wants to go into the hills with her girlfriends to mourn. Jephte sends his daughter to the hills (Vade, filia). She mourns her virginity, mourns not bearing a son that will weep at her tomb, mourns not living life now that everybody rejoices victory. She wants the valeys and caves to echo with horrifying sounds, reminding me of natures reaction to Christs death so vividly described by the Blitzen und Donner in Bach's passion according to st. Mathews . In the grand final chorus (plorate filii Israel) all weep for her, the dissonants of the lamentamini making her pain audible.

The virgins lamenting Jephtes daughter

We spend a long time rehearsing the piece and it took a long time before the pieces finally came together. Sometimes, rehearing is frustrating, you feel like you don't make any progress. However, we have lots of good laughs in between, and I generally come home singing sotto voce and feeling happy after rehearsals, even after being scolded by Jeanet (our conductor) for not practising enough. And performing such a piece with the accompanying instruments, hearing how the main drama between Jephte and his daughter is unfolding between Ilse and Govert is enough to give you goose bumps[1]. We performed the piece twice before in a joint concert with Novafonie , and it was a great succes. I hope we will be at least as succesful this time.

[1] Steffen does a great Job too, but Carissimi has not given the historian as dramatic a role.

Wednesday, April 06, 2005

Anjo Anjewierden: Comment on Getting Wet 

In Anjo Anjewierden: Comment on Getting Wet Anjo describes a model of a blogging community as a network of pipes. We have been discussing this earlier and I originally proposed him an electrical model which is very similar physically, where links are modelled as resistors.

Actually I think the electrical network model is slightly richer. At first approximation you could make the "resistance" R of each link uniform say 1 Ohm. But on second thought there is also a characteristic time lag to be taken into account : the time in (days say) it typically takes for the reader to discover the link. In this electrical model the easiest way to model that (IMHO) is to to think of a blogger as a capicitor that is being charged. For a lag of a day with a 1 ohm resistor, the capacitance C would be 24*60*60 Farad. As is well known in electrical engineering, this makes the blog a frequency dependent purely imaginary node in the resistance network.

Z = 2pi sqrt(-1) f C

I find it sort of amusing that blogs turn up imaginary but as Robert Dijkgraaf pointed out in the NRC this weekend, nature is certainly complex. Every time a blog enters the network at time T that corresponds to an electrical (delta) pulse with spectrum exp( 2pi sqrt(-1) fT ) / 2pi.

Note that this gives the model two degrees of freedom : R and C.

This capitance model should give qualitatively different results from those of a pure resistor network with a more or less static current distribution. The reason is that the pulses contain lots of high frequency components and those HF components see little resistance in the capicitors. However at the edges of the network the pulses are smeared out and you effectively see a net avarage direct current component (this is how the rectifier in a computers powersupply works). That direct current component then trickles through slowly to other networks if they are connected.
What this models intuitively is that within a lively community the timescales for the spread of information can be quite different from that between the edges of two communities.

By the way we should only count links pointing _to_ a blog as they can be read by someone else and allow information to be passed on to someone else. In a related vein the model ignores the fact that information streams cannot be negative. We should just ignore this, unless we get large negative *average* flows.

Thursday, January 13, 2005

Information overload 

Like Anjo I made some slides on information overload.

Information Overload

What is the problem ?  

  • Information overload is a form of cognitive (over)load
  • It comes from having to filter and judge more potentially useful information than a person can handle
Corollary : the Less is More principle:
There is a point where the extra benefit of providing more information is negative because it increases the cognitive load (cost) of getting at the more useful information.
The cost of not knowing may outweigh the cost of finding out.

Examples of Information overload

  • Overflowing mailboxes
  • Google queries with 12000 hits
  • so many (e-mails, papers, reports, meetings, conferences, blogs, documentation. memo's) to read/attend that there is no time to think anymore

What causes Information overload

  • Too much too insufficiently relevant information which technogy makes too easy to make available in ``raw'' form.
  • Anxiety to remain "in the loop'' and social pressure to keep people "in the loop".
  • Insufficient context: Judging and interpreting information is harder if you don't have the context of the producer. People often don't notice because they think the context is ``obvious'', and it is hard for Technology to preserve the context.
    •  many children will explain things by giving an example. Sometimes giving an example seems childish but are good examples undervalued ? 

What is the Result of Info overload ?

  • causes stress
  • People think they ought to know because they potentially can
  • Creates defensive strategies
    •   "Better" to stop looking for info
    •   "Look under the lattern for the lost key" i.e. only look where you can still see through the mess
    • spreadsheet syndrome : the world is what my spreadsheet says, if that fails make the world conform the spreadsheat
  • Loss of oversight
  • Hard to distinguish details from the essentials
  • time loss
    • how much on what actually ???

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© Copyright 2004-2006 Rogier Brussee.
These are my personal views and do not necessarily reflect those of my employer.